/deps/v8/src/jsregexp.cc
C++ | 6113 lines | 4598 code | 684 blank | 831 comment | 1004 complexity | aef8ad3ebb01bc84c3cbdd8aea488a1e MD5 | raw file
Possible License(s): 0BSD, Apache-2.0, MPL-2.0-no-copyleft-exception, JSON, WTFPL, CC-BY-SA-3.0, Unlicense, ISC, BSD-3-Clause, MIT, AGPL-3.0
- // Copyright 2012 the V8 project authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "src/v8.h"
- #include "src/ast.h"
- #include "src/base/platform/platform.h"
- #include "src/compilation-cache.h"
- #include "src/compiler.h"
- #include "src/execution.h"
- #include "src/factory.h"
- #include "src/jsregexp-inl.h"
- #include "src/jsregexp.h"
- #include "src/ostreams.h"
- #include "src/parser.h"
- #include "src/regexp-macro-assembler.h"
- #include "src/regexp-macro-assembler-irregexp.h"
- #include "src/regexp-macro-assembler-tracer.h"
- #include "src/regexp-stack.h"
- #include "src/runtime.h"
- #include "src/string-search.h"
- #ifndef V8_INTERPRETED_REGEXP
- #if V8_TARGET_ARCH_IA32
- #include "src/ia32/regexp-macro-assembler-ia32.h" // NOLINT
- #elif V8_TARGET_ARCH_X64
- #include "src/x64/regexp-macro-assembler-x64.h" // NOLINT
- #elif V8_TARGET_ARCH_ARM64
- #include "src/arm64/regexp-macro-assembler-arm64.h" // NOLINT
- #elif V8_TARGET_ARCH_ARM
- #include "src/arm/regexp-macro-assembler-arm.h" // NOLINT
- #elif V8_TARGET_ARCH_MIPS
- #include "src/mips/regexp-macro-assembler-mips.h" // NOLINT
- #elif V8_TARGET_ARCH_MIPS64
- #include "src/mips64/regexp-macro-assembler-mips64.h" // NOLINT
- #elif V8_TARGET_ARCH_X87
- #include "src/x87/regexp-macro-assembler-x87.h" // NOLINT
- #else
- #error Unsupported target architecture.
- #endif
- #endif
- #include "src/interpreter-irregexp.h"
- namespace v8 {
- namespace internal {
- MaybeHandle<Object> RegExpImpl::CreateRegExpLiteral(
- Handle<JSFunction> constructor,
- Handle<String> pattern,
- Handle<String> flags) {
- // Call the construct code with 2 arguments.
- Handle<Object> argv[] = { pattern, flags };
- return Execution::New(constructor, ARRAY_SIZE(argv), argv);
- }
- static JSRegExp::Flags RegExpFlagsFromString(Handle<String> str) {
- int flags = JSRegExp::NONE;
- for (int i = 0; i < str->length(); i++) {
- switch (str->Get(i)) {
- case 'i':
- flags |= JSRegExp::IGNORE_CASE;
- break;
- case 'g':
- flags |= JSRegExp::GLOBAL;
- break;
- case 'm':
- flags |= JSRegExp::MULTILINE;
- break;
- }
- }
- return JSRegExp::Flags(flags);
- }
- MUST_USE_RESULT
- static inline MaybeHandle<Object> ThrowRegExpException(
- Handle<JSRegExp> re,
- Handle<String> pattern,
- Handle<String> error_text,
- const char* message) {
- Isolate* isolate = re->GetIsolate();
- Factory* factory = isolate->factory();
- Handle<FixedArray> elements = factory->NewFixedArray(2);
- elements->set(0, *pattern);
- elements->set(1, *error_text);
- Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
- Handle<Object> regexp_err = factory->NewSyntaxError(message, array);
- return isolate->Throw<Object>(regexp_err);
- }
- ContainedInLattice AddRange(ContainedInLattice containment,
- const int* ranges,
- int ranges_length,
- Interval new_range) {
- DCHECK((ranges_length & 1) == 1);
- DCHECK(ranges[ranges_length - 1] == String::kMaxUtf16CodeUnit + 1);
- if (containment == kLatticeUnknown) return containment;
- bool inside = false;
- int last = 0;
- for (int i = 0; i < ranges_length; inside = !inside, last = ranges[i], i++) {
- // Consider the range from last to ranges[i].
- // We haven't got to the new range yet.
- if (ranges[i] <= new_range.from()) continue;
- // New range is wholly inside last-ranges[i]. Note that new_range.to() is
- // inclusive, but the values in ranges are not.
- if (last <= new_range.from() && new_range.to() < ranges[i]) {
- return Combine(containment, inside ? kLatticeIn : kLatticeOut);
- }
- return kLatticeUnknown;
- }
- return containment;
- }
- // More makes code generation slower, less makes V8 benchmark score lower.
- const int kMaxLookaheadForBoyerMoore = 8;
- // In a 3-character pattern you can maximally step forwards 3 characters
- // at a time, which is not always enough to pay for the extra logic.
- const int kPatternTooShortForBoyerMoore = 2;
- // Identifies the sort of regexps where the regexp engine is faster
- // than the code used for atom matches.
- static bool HasFewDifferentCharacters(Handle<String> pattern) {
- int length = Min(kMaxLookaheadForBoyerMoore, pattern->length());
- if (length <= kPatternTooShortForBoyerMoore) return false;
- const int kMod = 128;
- bool character_found[kMod];
- int different = 0;
- memset(&character_found[0], 0, sizeof(character_found));
- for (int i = 0; i < length; i++) {
- int ch = (pattern->Get(i) & (kMod - 1));
- if (!character_found[ch]) {
- character_found[ch] = true;
- different++;
- // We declare a regexp low-alphabet if it has at least 3 times as many
- // characters as it has different characters.
- if (different * 3 > length) return false;
- }
- }
- return true;
- }
- // Generic RegExp methods. Dispatches to implementation specific methods.
- MaybeHandle<Object> RegExpImpl::Compile(Handle<JSRegExp> re,
- Handle<String> pattern,
- Handle<String> flag_str) {
- Isolate* isolate = re->GetIsolate();
- Zone zone(isolate);
- JSRegExp::Flags flags = RegExpFlagsFromString(flag_str);
- CompilationCache* compilation_cache = isolate->compilation_cache();
- MaybeHandle<FixedArray> maybe_cached =
- compilation_cache->LookupRegExp(pattern, flags);
- Handle<FixedArray> cached;
- bool in_cache = maybe_cached.ToHandle(&cached);
- LOG(isolate, RegExpCompileEvent(re, in_cache));
- Handle<Object> result;
- if (in_cache) {
- re->set_data(*cached);
- return re;
- }
- pattern = String::Flatten(pattern);
- PostponeInterruptsScope postpone(isolate);
- RegExpCompileData parse_result;
- FlatStringReader reader(isolate, pattern);
- if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
- &parse_result, &zone)) {
- // Throw an exception if we fail to parse the pattern.
- return ThrowRegExpException(re,
- pattern,
- parse_result.error,
- "malformed_regexp");
- }
- bool has_been_compiled = false;
- if (parse_result.simple &&
- !flags.is_ignore_case() &&
- !HasFewDifferentCharacters(pattern)) {
- // Parse-tree is a single atom that is equal to the pattern.
- AtomCompile(re, pattern, flags, pattern);
- has_been_compiled = true;
- } else if (parse_result.tree->IsAtom() &&
- !flags.is_ignore_case() &&
- parse_result.capture_count == 0) {
- RegExpAtom* atom = parse_result.tree->AsAtom();
- Vector<const uc16> atom_pattern = atom->data();
- Handle<String> atom_string;
- ASSIGN_RETURN_ON_EXCEPTION(
- isolate, atom_string,
- isolate->factory()->NewStringFromTwoByte(atom_pattern),
- Object);
- if (!HasFewDifferentCharacters(atom_string)) {
- AtomCompile(re, pattern, flags, atom_string);
- has_been_compiled = true;
- }
- }
- if (!has_been_compiled) {
- IrregexpInitialize(re, pattern, flags, parse_result.capture_count);
- }
- DCHECK(re->data()->IsFixedArray());
- // Compilation succeeded so the data is set on the regexp
- // and we can store it in the cache.
- Handle<FixedArray> data(FixedArray::cast(re->data()));
- compilation_cache->PutRegExp(pattern, flags, data);
- return re;
- }
- MaybeHandle<Object> RegExpImpl::Exec(Handle<JSRegExp> regexp,
- Handle<String> subject,
- int index,
- Handle<JSArray> last_match_info) {
- switch (regexp->TypeTag()) {
- case JSRegExp::ATOM:
- return AtomExec(regexp, subject, index, last_match_info);
- case JSRegExp::IRREGEXP: {
- return IrregexpExec(regexp, subject, index, last_match_info);
- }
- default:
- UNREACHABLE();
- return MaybeHandle<Object>();
- }
- }
- // RegExp Atom implementation: Simple string search using indexOf.
- void RegExpImpl::AtomCompile(Handle<JSRegExp> re,
- Handle<String> pattern,
- JSRegExp::Flags flags,
- Handle<String> match_pattern) {
- re->GetIsolate()->factory()->SetRegExpAtomData(re,
- JSRegExp::ATOM,
- pattern,
- flags,
- match_pattern);
- }
- static void SetAtomLastCapture(FixedArray* array,
- String* subject,
- int from,
- int to) {
- SealHandleScope shs(array->GetIsolate());
- RegExpImpl::SetLastCaptureCount(array, 2);
- RegExpImpl::SetLastSubject(array, subject);
- RegExpImpl::SetLastInput(array, subject);
- RegExpImpl::SetCapture(array, 0, from);
- RegExpImpl::SetCapture(array, 1, to);
- }
- int RegExpImpl::AtomExecRaw(Handle<JSRegExp> regexp,
- Handle<String> subject,
- int index,
- int32_t* output,
- int output_size) {
- Isolate* isolate = regexp->GetIsolate();
- DCHECK(0 <= index);
- DCHECK(index <= subject->length());
- subject = String::Flatten(subject);
- DisallowHeapAllocation no_gc; // ensure vectors stay valid
- String* needle = String::cast(regexp->DataAt(JSRegExp::kAtomPatternIndex));
- int needle_len = needle->length();
- DCHECK(needle->IsFlat());
- DCHECK_LT(0, needle_len);
- if (index + needle_len > subject->length()) {
- return RegExpImpl::RE_FAILURE;
- }
- for (int i = 0; i < output_size; i += 2) {
- String::FlatContent needle_content = needle->GetFlatContent();
- String::FlatContent subject_content = subject->GetFlatContent();
- DCHECK(needle_content.IsFlat());
- DCHECK(subject_content.IsFlat());
- // dispatch on type of strings
- index = (needle_content.IsAscii()
- ? (subject_content.IsAscii()
- ? SearchString(isolate,
- subject_content.ToOneByteVector(),
- needle_content.ToOneByteVector(),
- index)
- : SearchString(isolate,
- subject_content.ToUC16Vector(),
- needle_content.ToOneByteVector(),
- index))
- : (subject_content.IsAscii()
- ? SearchString(isolate,
- subject_content.ToOneByteVector(),
- needle_content.ToUC16Vector(),
- index)
- : SearchString(isolate,
- subject_content.ToUC16Vector(),
- needle_content.ToUC16Vector(),
- index)));
- if (index == -1) {
- return i / 2; // Return number of matches.
- } else {
- output[i] = index;
- output[i+1] = index + needle_len;
- index += needle_len;
- }
- }
- return output_size / 2;
- }
- Handle<Object> RegExpImpl::AtomExec(Handle<JSRegExp> re,
- Handle<String> subject,
- int index,
- Handle<JSArray> last_match_info) {
- Isolate* isolate = re->GetIsolate();
- static const int kNumRegisters = 2;
- STATIC_ASSERT(kNumRegisters <= Isolate::kJSRegexpStaticOffsetsVectorSize);
- int32_t* output_registers = isolate->jsregexp_static_offsets_vector();
- int res = AtomExecRaw(re, subject, index, output_registers, kNumRegisters);
- if (res == RegExpImpl::RE_FAILURE) return isolate->factory()->null_value();
- DCHECK_EQ(res, RegExpImpl::RE_SUCCESS);
- SealHandleScope shs(isolate);
- FixedArray* array = FixedArray::cast(last_match_info->elements());
- SetAtomLastCapture(array, *subject, output_registers[0], output_registers[1]);
- return last_match_info;
- }
- // Irregexp implementation.
- // Ensures that the regexp object contains a compiled version of the
- // source for either ASCII or non-ASCII strings.
- // If the compiled version doesn't already exist, it is compiled
- // from the source pattern.
- // If compilation fails, an exception is thrown and this function
- // returns false.
- bool RegExpImpl::EnsureCompiledIrregexp(
- Handle<JSRegExp> re, Handle<String> sample_subject, bool is_ascii) {
- Object* compiled_code = re->DataAt(JSRegExp::code_index(is_ascii));
- #ifdef V8_INTERPRETED_REGEXP
- if (compiled_code->IsByteArray()) return true;
- #else // V8_INTERPRETED_REGEXP (RegExp native code)
- if (compiled_code->IsCode()) return true;
- #endif
- // We could potentially have marked this as flushable, but have kept
- // a saved version if we did not flush it yet.
- Object* saved_code = re->DataAt(JSRegExp::saved_code_index(is_ascii));
- if (saved_code->IsCode()) {
- // Reinstate the code in the original place.
- re->SetDataAt(JSRegExp::code_index(is_ascii), saved_code);
- DCHECK(compiled_code->IsSmi());
- return true;
- }
- return CompileIrregexp(re, sample_subject, is_ascii);
- }
- static bool CreateRegExpErrorObjectAndThrow(Handle<JSRegExp> re,
- bool is_ascii,
- Handle<String> error_message,
- Isolate* isolate) {
- Factory* factory = isolate->factory();
- Handle<FixedArray> elements = factory->NewFixedArray(2);
- elements->set(0, re->Pattern());
- elements->set(1, *error_message);
- Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
- Handle<Object> regexp_err =
- factory->NewSyntaxError("malformed_regexp", array);
- isolate->Throw(*regexp_err);
- return false;
- }
- bool RegExpImpl::CompileIrregexp(Handle<JSRegExp> re,
- Handle<String> sample_subject,
- bool is_ascii) {
- // Compile the RegExp.
- Isolate* isolate = re->GetIsolate();
- Zone zone(isolate);
- PostponeInterruptsScope postpone(isolate);
- // If we had a compilation error the last time this is saved at the
- // saved code index.
- Object* entry = re->DataAt(JSRegExp::code_index(is_ascii));
- // When arriving here entry can only be a smi, either representing an
- // uncompiled regexp, a previous compilation error, or code that has
- // been flushed.
- DCHECK(entry->IsSmi());
- int entry_value = Smi::cast(entry)->value();
- DCHECK(entry_value == JSRegExp::kUninitializedValue ||
- entry_value == JSRegExp::kCompilationErrorValue ||
- (entry_value < JSRegExp::kCodeAgeMask && entry_value >= 0));
- if (entry_value == JSRegExp::kCompilationErrorValue) {
- // A previous compilation failed and threw an error which we store in
- // the saved code index (we store the error message, not the actual
- // error). Recreate the error object and throw it.
- Object* error_string = re->DataAt(JSRegExp::saved_code_index(is_ascii));
- DCHECK(error_string->IsString());
- Handle<String> error_message(String::cast(error_string));
- CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
- return false;
- }
- JSRegExp::Flags flags = re->GetFlags();
- Handle<String> pattern(re->Pattern());
- pattern = String::Flatten(pattern);
- RegExpCompileData compile_data;
- FlatStringReader reader(isolate, pattern);
- if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
- &compile_data,
- &zone)) {
- // Throw an exception if we fail to parse the pattern.
- // THIS SHOULD NOT HAPPEN. We already pre-parsed it successfully once.
- USE(ThrowRegExpException(re,
- pattern,
- compile_data.error,
- "malformed_regexp"));
- return false;
- }
- RegExpEngine::CompilationResult result =
- RegExpEngine::Compile(&compile_data,
- flags.is_ignore_case(),
- flags.is_global(),
- flags.is_multiline(),
- pattern,
- sample_subject,
- is_ascii,
- &zone);
- if (result.error_message != NULL) {
- // Unable to compile regexp.
- Handle<String> error_message = isolate->factory()->NewStringFromUtf8(
- CStrVector(result.error_message)).ToHandleChecked();
- CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
- return false;
- }
- Handle<FixedArray> data = Handle<FixedArray>(FixedArray::cast(re->data()));
- data->set(JSRegExp::code_index(is_ascii), result.code);
- int register_max = IrregexpMaxRegisterCount(*data);
- if (result.num_registers > register_max) {
- SetIrregexpMaxRegisterCount(*data, result.num_registers);
- }
- return true;
- }
- int RegExpImpl::IrregexpMaxRegisterCount(FixedArray* re) {
- return Smi::cast(
- re->get(JSRegExp::kIrregexpMaxRegisterCountIndex))->value();
- }
- void RegExpImpl::SetIrregexpMaxRegisterCount(FixedArray* re, int value) {
- re->set(JSRegExp::kIrregexpMaxRegisterCountIndex, Smi::FromInt(value));
- }
- int RegExpImpl::IrregexpNumberOfCaptures(FixedArray* re) {
- return Smi::cast(re->get(JSRegExp::kIrregexpCaptureCountIndex))->value();
- }
- int RegExpImpl::IrregexpNumberOfRegisters(FixedArray* re) {
- return Smi::cast(re->get(JSRegExp::kIrregexpMaxRegisterCountIndex))->value();
- }
- ByteArray* RegExpImpl::IrregexpByteCode(FixedArray* re, bool is_ascii) {
- return ByteArray::cast(re->get(JSRegExp::code_index(is_ascii)));
- }
- Code* RegExpImpl::IrregexpNativeCode(FixedArray* re, bool is_ascii) {
- return Code::cast(re->get(JSRegExp::code_index(is_ascii)));
- }
- void RegExpImpl::IrregexpInitialize(Handle<JSRegExp> re,
- Handle<String> pattern,
- JSRegExp::Flags flags,
- int capture_count) {
- // Initialize compiled code entries to null.
- re->GetIsolate()->factory()->SetRegExpIrregexpData(re,
- JSRegExp::IRREGEXP,
- pattern,
- flags,
- capture_count);
- }
- int RegExpImpl::IrregexpPrepare(Handle<JSRegExp> regexp,
- Handle<String> subject) {
- subject = String::Flatten(subject);
- // Check the asciiness of the underlying storage.
- bool is_ascii = subject->IsOneByteRepresentationUnderneath();
- if (!EnsureCompiledIrregexp(regexp, subject, is_ascii)) return -1;
- #ifdef V8_INTERPRETED_REGEXP
- // Byte-code regexp needs space allocated for all its registers.
- // The result captures are copied to the start of the registers array
- // if the match succeeds. This way those registers are not clobbered
- // when we set the last match info from last successful match.
- return IrregexpNumberOfRegisters(FixedArray::cast(regexp->data())) +
- (IrregexpNumberOfCaptures(FixedArray::cast(regexp->data())) + 1) * 2;
- #else // V8_INTERPRETED_REGEXP
- // Native regexp only needs room to output captures. Registers are handled
- // internally.
- return (IrregexpNumberOfCaptures(FixedArray::cast(regexp->data())) + 1) * 2;
- #endif // V8_INTERPRETED_REGEXP
- }
- int RegExpImpl::IrregexpExecRaw(Handle<JSRegExp> regexp,
- Handle<String> subject,
- int index,
- int32_t* output,
- int output_size) {
- Isolate* isolate = regexp->GetIsolate();
- Handle<FixedArray> irregexp(FixedArray::cast(regexp->data()), isolate);
- DCHECK(index >= 0);
- DCHECK(index <= subject->length());
- DCHECK(subject->IsFlat());
- bool is_ascii = subject->IsOneByteRepresentationUnderneath();
- #ifndef V8_INTERPRETED_REGEXP
- DCHECK(output_size >= (IrregexpNumberOfCaptures(*irregexp) + 1) * 2);
- do {
- EnsureCompiledIrregexp(regexp, subject, is_ascii);
- Handle<Code> code(IrregexpNativeCode(*irregexp, is_ascii), isolate);
- // The stack is used to allocate registers for the compiled regexp code.
- // This means that in case of failure, the output registers array is left
- // untouched and contains the capture results from the previous successful
- // match. We can use that to set the last match info lazily.
- NativeRegExpMacroAssembler::Result res =
- NativeRegExpMacroAssembler::Match(code,
- subject,
- output,
- output_size,
- index,
- isolate);
- if (res != NativeRegExpMacroAssembler::RETRY) {
- DCHECK(res != NativeRegExpMacroAssembler::EXCEPTION ||
- isolate->has_pending_exception());
- STATIC_ASSERT(
- static_cast<int>(NativeRegExpMacroAssembler::SUCCESS) == RE_SUCCESS);
- STATIC_ASSERT(
- static_cast<int>(NativeRegExpMacroAssembler::FAILURE) == RE_FAILURE);
- STATIC_ASSERT(static_cast<int>(NativeRegExpMacroAssembler::EXCEPTION)
- == RE_EXCEPTION);
- return static_cast<IrregexpResult>(res);
- }
- // If result is RETRY, the string has changed representation, and we
- // must restart from scratch.
- // In this case, it means we must make sure we are prepared to handle
- // the, potentially, different subject (the string can switch between
- // being internal and external, and even between being ASCII and UC16,
- // but the characters are always the same).
- IrregexpPrepare(regexp, subject);
- is_ascii = subject->IsOneByteRepresentationUnderneath();
- } while (true);
- UNREACHABLE();
- return RE_EXCEPTION;
- #else // V8_INTERPRETED_REGEXP
- DCHECK(output_size >= IrregexpNumberOfRegisters(*irregexp));
- // We must have done EnsureCompiledIrregexp, so we can get the number of
- // registers.
- int number_of_capture_registers =
- (IrregexpNumberOfCaptures(*irregexp) + 1) * 2;
- int32_t* raw_output = &output[number_of_capture_registers];
- // We do not touch the actual capture result registers until we know there
- // has been a match so that we can use those capture results to set the
- // last match info.
- for (int i = number_of_capture_registers - 1; i >= 0; i--) {
- raw_output[i] = -1;
- }
- Handle<ByteArray> byte_codes(IrregexpByteCode(*irregexp, is_ascii), isolate);
- IrregexpResult result = IrregexpInterpreter::Match(isolate,
- byte_codes,
- subject,
- raw_output,
- index);
- if (result == RE_SUCCESS) {
- // Copy capture results to the start of the registers array.
- MemCopy(output, raw_output, number_of_capture_registers * sizeof(int32_t));
- }
- if (result == RE_EXCEPTION) {
- DCHECK(!isolate->has_pending_exception());
- isolate->StackOverflow();
- }
- return result;
- #endif // V8_INTERPRETED_REGEXP
- }
- MaybeHandle<Object> RegExpImpl::IrregexpExec(Handle<JSRegExp> regexp,
- Handle<String> subject,
- int previous_index,
- Handle<JSArray> last_match_info) {
- Isolate* isolate = regexp->GetIsolate();
- DCHECK_EQ(regexp->TypeTag(), JSRegExp::IRREGEXP);
- // Prepare space for the return values.
- #if defined(V8_INTERPRETED_REGEXP) && defined(DEBUG)
- if (FLAG_trace_regexp_bytecodes) {
- String* pattern = regexp->Pattern();
- PrintF("\n\nRegexp match: /%s/\n\n", pattern->ToCString().get());
- PrintF("\n\nSubject string: '%s'\n\n", subject->ToCString().get());
- }
- #endif
- int required_registers = RegExpImpl::IrregexpPrepare(regexp, subject);
- if (required_registers < 0) {
- // Compiling failed with an exception.
- DCHECK(isolate->has_pending_exception());
- return MaybeHandle<Object>();
- }
- int32_t* output_registers = NULL;
- if (required_registers > Isolate::kJSRegexpStaticOffsetsVectorSize) {
- output_registers = NewArray<int32_t>(required_registers);
- }
- SmartArrayPointer<int32_t> auto_release(output_registers);
- if (output_registers == NULL) {
- output_registers = isolate->jsregexp_static_offsets_vector();
- }
- int res = RegExpImpl::IrregexpExecRaw(
- regexp, subject, previous_index, output_registers, required_registers);
- if (res == RE_SUCCESS) {
- int capture_count =
- IrregexpNumberOfCaptures(FixedArray::cast(regexp->data()));
- return SetLastMatchInfo(
- last_match_info, subject, capture_count, output_registers);
- }
- if (res == RE_EXCEPTION) {
- DCHECK(isolate->has_pending_exception());
- return MaybeHandle<Object>();
- }
- DCHECK(res == RE_FAILURE);
- return isolate->factory()->null_value();
- }
- Handle<JSArray> RegExpImpl::SetLastMatchInfo(Handle<JSArray> last_match_info,
- Handle<String> subject,
- int capture_count,
- int32_t* match) {
- DCHECK(last_match_info->HasFastObjectElements());
- int capture_register_count = (capture_count + 1) * 2;
- JSArray::EnsureSize(last_match_info,
- capture_register_count + kLastMatchOverhead);
- DisallowHeapAllocation no_allocation;
- FixedArray* array = FixedArray::cast(last_match_info->elements());
- if (match != NULL) {
- for (int i = 0; i < capture_register_count; i += 2) {
- SetCapture(array, i, match[i]);
- SetCapture(array, i + 1, match[i + 1]);
- }
- }
- SetLastCaptureCount(array, capture_register_count);
- SetLastSubject(array, *subject);
- SetLastInput(array, *subject);
- return last_match_info;
- }
- RegExpImpl::GlobalCache::GlobalCache(Handle<JSRegExp> regexp,
- Handle<String> subject,
- bool is_global,
- Isolate* isolate)
- : register_array_(NULL),
- register_array_size_(0),
- regexp_(regexp),
- subject_(subject) {
- #ifdef V8_INTERPRETED_REGEXP
- bool interpreted = true;
- #else
- bool interpreted = false;
- #endif // V8_INTERPRETED_REGEXP
- if (regexp_->TypeTag() == JSRegExp::ATOM) {
- static const int kAtomRegistersPerMatch = 2;
- registers_per_match_ = kAtomRegistersPerMatch;
- // There is no distinction between interpreted and native for atom regexps.
- interpreted = false;
- } else {
- registers_per_match_ = RegExpImpl::IrregexpPrepare(regexp_, subject_);
- if (registers_per_match_ < 0) {
- num_matches_ = -1; // Signal exception.
- return;
- }
- }
- if (is_global && !interpreted) {
- register_array_size_ =
- Max(registers_per_match_, Isolate::kJSRegexpStaticOffsetsVectorSize);
- max_matches_ = register_array_size_ / registers_per_match_;
- } else {
- // Global loop in interpreted regexp is not implemented. We choose
- // the size of the offsets vector so that it can only store one match.
- register_array_size_ = registers_per_match_;
- max_matches_ = 1;
- }
- if (register_array_size_ > Isolate::kJSRegexpStaticOffsetsVectorSize) {
- register_array_ = NewArray<int32_t>(register_array_size_);
- } else {
- register_array_ = isolate->jsregexp_static_offsets_vector();
- }
- // Set state so that fetching the results the first time triggers a call
- // to the compiled regexp.
- current_match_index_ = max_matches_ - 1;
- num_matches_ = max_matches_;
- DCHECK(registers_per_match_ >= 2); // Each match has at least one capture.
- DCHECK_GE(register_array_size_, registers_per_match_);
- int32_t* last_match =
- ®ister_array_[current_match_index_ * registers_per_match_];
- last_match[0] = -1;
- last_match[1] = 0;
- }
- // -------------------------------------------------------------------
- // Implementation of the Irregexp regular expression engine.
- //
- // The Irregexp regular expression engine is intended to be a complete
- // implementation of ECMAScript regular expressions. It generates either
- // bytecodes or native code.
- // The Irregexp regexp engine is structured in three steps.
- // 1) The parser generates an abstract syntax tree. See ast.cc.
- // 2) From the AST a node network is created. The nodes are all
- // subclasses of RegExpNode. The nodes represent states when
- // executing a regular expression. Several optimizations are
- // performed on the node network.
- // 3) From the nodes we generate either byte codes or native code
- // that can actually execute the regular expression (perform
- // the search). The code generation step is described in more
- // detail below.
- // Code generation.
- //
- // The nodes are divided into four main categories.
- // * Choice nodes
- // These represent places where the regular expression can
- // match in more than one way. For example on entry to an
- // alternation (foo|bar) or a repetition (*, +, ? or {}).
- // * Action nodes
- // These represent places where some action should be
- // performed. Examples include recording the current position
- // in the input string to a register (in order to implement
- // captures) or other actions on register for example in order
- // to implement the counters needed for {} repetitions.
- // * Matching nodes
- // These attempt to match some element part of the input string.
- // Examples of elements include character classes, plain strings
- // or back references.
- // * End nodes
- // These are used to implement the actions required on finding
- // a successful match or failing to find a match.
- //
- // The code generated (whether as byte codes or native code) maintains
- // some state as it runs. This consists of the following elements:
- //
- // * The capture registers. Used for string captures.
- // * Other registers. Used for counters etc.
- // * The current position.
- // * The stack of backtracking information. Used when a matching node
- // fails to find a match and needs to try an alternative.
- //
- // Conceptual regular expression execution model:
- //
- // There is a simple conceptual model of regular expression execution
- // which will be presented first. The actual code generated is a more
- // efficient simulation of the simple conceptual model:
- //
- // * Choice nodes are implemented as follows:
- // For each choice except the last {
- // push current position
- // push backtrack code location
- // <generate code to test for choice>
- // backtrack code location:
- // pop current position
- // }
- // <generate code to test for last choice>
- //
- // * Actions nodes are generated as follows
- // <push affected registers on backtrack stack>
- // <generate code to perform action>
- // push backtrack code location
- // <generate code to test for following nodes>
- // backtrack code location:
- // <pop affected registers to restore their state>
- // <pop backtrack location from stack and go to it>
- //
- // * Matching nodes are generated as follows:
- // if input string matches at current position
- // update current position
- // <generate code to test for following nodes>
- // else
- // <pop backtrack location from stack and go to it>
- //
- // Thus it can be seen that the current position is saved and restored
- // by the choice nodes, whereas the registers are saved and restored by
- // by the action nodes that manipulate them.
- //
- // The other interesting aspect of this model is that nodes are generated
- // at the point where they are needed by a recursive call to Emit(). If
- // the node has already been code generated then the Emit() call will
- // generate a jump to the previously generated code instead. In order to
- // limit recursion it is possible for the Emit() function to put the node
- // on a work list for later generation and instead generate a jump. The
- // destination of the jump is resolved later when the code is generated.
- //
- // Actual regular expression code generation.
- //
- // Code generation is actually more complicated than the above. In order
- // to improve the efficiency of the generated code some optimizations are
- // performed
- //
- // * Choice nodes have 1-character lookahead.
- // A choice node looks at the following character and eliminates some of
- // the choices immediately based on that character. This is not yet
- // implemented.
- // * Simple greedy loops store reduced backtracking information.
- // A quantifier like /.*foo/m will greedily match the whole input. It will
- // then need to backtrack to a point where it can match "foo". The naive
- // implementation of this would push each character position onto the
- // backtracking stack, then pop them off one by one. This would use space
- // proportional to the length of the input string. However since the "."
- // can only match in one way and always has a constant length (in this case
- // of 1) it suffices to store the current position on the top of the stack
- // once. Matching now becomes merely incrementing the current position and
- // backtracking becomes decrementing the current position and checking the
- // result against the stored current position. This is faster and saves
- // space.
- // * The current state is virtualized.
- // This is used to defer expensive operations until it is clear that they
- // are needed and to generate code for a node more than once, allowing
- // specialized an efficient versions of the code to be created. This is
- // explained in the section below.
- //
- // Execution state virtualization.
- //
- // Instead of emitting code, nodes that manipulate the state can record their
- // manipulation in an object called the Trace. The Trace object can record a
- // current position offset, an optional backtrack code location on the top of
- // the virtualized backtrack stack and some register changes. When a node is
- // to be emitted it can flush the Trace or update it. Flushing the Trace
- // will emit code to bring the actual state into line with the virtual state.
- // Avoiding flushing the state can postpone some work (e.g. updates of capture
- // registers). Postponing work can save time when executing the regular
- // expression since it may be found that the work never has to be done as a
- // failure to match can occur. In addition it is much faster to jump to a
- // known backtrack code location than it is to pop an unknown backtrack
- // location from the stack and jump there.
- //
- // The virtual state found in the Trace affects code generation. For example
- // the virtual state contains the difference between the actual current
- // position and the virtual current position, and matching code needs to use
- // this offset to attempt a match in the correct location of the input
- // string. Therefore code generated for a non-trivial trace is specialized
- // to that trace. The code generator therefore has the ability to generate
- // code for each node several times. In order to limit the size of the
- // generated code there is an arbitrary limit on how many specialized sets of
- // code may be generated for a given node. If the limit is reached, the
- // trace is flushed and a generic version of the code for a node is emitted.
- // This is subsequently used for that node. The code emitted for non-generic
- // trace is not recorded in the node and so it cannot currently be reused in
- // the event that code generation is requested for an identical trace.
- void RegExpTree::AppendToText(RegExpText* text, Zone* zone) {
- UNREACHABLE();
- }
- void RegExpAtom::AppendToText(RegExpText* text, Zone* zone) {
- text->AddElement(TextElement::Atom(this), zone);
- }
- void RegExpCharacterClass::AppendToText(RegExpText* text, Zone* zone) {
- text->AddElement(TextElement::CharClass(this), zone);
- }
- void RegExpText::AppendToText(RegExpText* text, Zone* zone) {
- for (int i = 0; i < elements()->length(); i++)
- text->AddElement(elements()->at(i), zone);
- }
- TextElement TextElement::Atom(RegExpAtom* atom) {
- return TextElement(ATOM, atom);
- }
- TextElement TextElement::CharClass(RegExpCharacterClass* char_class) {
- return TextElement(CHAR_CLASS, char_class);
- }
- int TextElement::length() const {
- switch (text_type()) {
- case ATOM:
- return atom()->length();
- case CHAR_CLASS:
- return 1;
- }
- UNREACHABLE();
- return 0;
- }
- DispatchTable* ChoiceNode::GetTable(bool ignore_case) {
- if (table_ == NULL) {
- table_ = new(zone()) DispatchTable(zone());
- DispatchTableConstructor cons(table_, ignore_case, zone());
- cons.BuildTable(this);
- }
- return table_;
- }
- class FrequencyCollator {
- public:
- FrequencyCollator() : total_samples_(0) {
- for (int i = 0; i < RegExpMacroAssembler::kTableSize; i++) {
- frequencies_[i] = CharacterFrequency(i);
- }
- }
- void CountCharacter(int character) {
- int index = (character & RegExpMacroAssembler::kTableMask);
- frequencies_[index].Increment();
- total_samples_++;
- }
- // Does not measure in percent, but rather per-128 (the table size from the
- // regexp macro assembler).
- int Frequency(int in_character) {
- DCHECK((in_character & RegExpMacroAssembler::kTableMask) == in_character);
- if (total_samples_ < 1) return 1; // Division by zero.
- int freq_in_per128 =
- (frequencies_[in_character].counter() * 128) / total_samples_;
- return freq_in_per128;
- }
- private:
- class CharacterFrequency {
- public:
- CharacterFrequency() : counter_(0), character_(-1) { }
- explicit CharacterFrequency(int character)
- : counter_(0), character_(character) { }
- void Increment() { counter_++; }
- int counter() { return counter_; }
- int character() { return character_; }
- private:
- int counter_;
- int character_;
- };
- private:
- CharacterFrequency frequencies_[RegExpMacroAssembler::kTableSize];
- int total_samples_;
- };
- class RegExpCompiler {
- public:
- RegExpCompiler(int capture_count, bool ignore_case, bool is_ascii,
- Zone* zone);
- int AllocateRegister() {
- if (next_register_ >= RegExpMacroAssembler::kMaxRegister) {
- reg_exp_too_big_ = true;
- return next_register_;
- }
- return next_register_++;
- }
- RegExpEngine::CompilationResult Assemble(RegExpMacroAssembler* assembler,
- RegExpNode* start,
- int capture_count,
- Handle<String> pattern);
- inline void AddWork(RegExpNode* node) { work_list_->Add(node); }
- static const int kImplementationOffset = 0;
- static const int kNumberOfRegistersOffset = 0;
- static const int kCodeOffset = 1;
- RegExpMacroAssembler* macro_assembler() { return macro_assembler_; }
- EndNode* accept() { return accept_; }
- static const int kMaxRecursion = 100;
- inline int recursion_depth() { return recursion_depth_; }
- inline void IncrementRecursionDepth() { recursion_depth_++; }
- inline void DecrementRecursionDepth() { recursion_depth_--; }
- void SetRegExpTooBig() { reg_exp_too_big_ = true; }
- inline bool ignore_case() { return ignore_case_; }
- inline bool ascii() { return ascii_; }
- FrequencyCollator* frequency_collator() { return &frequency_collator_; }
- int current_expansion_factor() { return current_expansion_factor_; }
- void set_current_expansion_factor(int value) {
- current_expansion_factor_ = value;
- }
- Zone* zone() const { return zone_; }
- static const int kNoRegister = -1;
- private:
- EndNode* accept_;
- int next_register_;
- List<RegExpNode*>* work_list_;
- int recursion_depth_;
- RegExpMacroAssembler* macro_assembler_;
- bool ignore_case_;
- bool ascii_;
- bool reg_exp_too_big_;
- int current_expansion_factor_;
- FrequencyCollator frequency_collator_;
- Zone* zone_;
- };
- class RecursionCheck {
- public:
- explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) {
- compiler->IncrementRecursionDepth();
- }
- ~RecursionCheck() { compiler_->DecrementRecursionDepth(); }
- private:
- RegExpCompiler* compiler_;
- };
- static RegExpEngine::CompilationResult IrregexpRegExpTooBig(Isolate* isolate) {
- return RegExpEngine::CompilationResult(isolate, "RegExp too big");
- }
- // Attempts to compile the regexp using an Irregexp code generator. Returns
- // a fixed array or a null handle depending on whether it succeeded.
- RegExpCompiler::RegExpCompiler(int capture_count, bool ignore_case, bool ascii,
- Zone* zone)
- : next_register_(2 * (capture_count + 1)),
- work_list_(NULL),
- recursion_depth_(0),
- ignore_case_(ignore_case),
- ascii_(ascii),
- reg_exp_too_big_(false),
- current_expansion_factor_(1),
- frequency_collator_(),
- zone_(zone) {
- accept_ = new(zone) EndNode(EndNode::ACCEPT, zone);
- DCHECK(next_register_ - 1 <= RegExpMacroAssembler::kMaxRegister);
- }
- RegExpEngine::CompilationResult RegExpCompiler::Assemble(
- RegExpMacroAssembler* macro_assembler,
- RegExpNode* start,
- int capture_count,
- Handle<String> pattern) {
- Heap* heap = pattern->GetHeap();
- bool use_slow_safe_regexp_compiler = false;
- if (heap->total_regexp_code_generated() >
- RegExpImpl::kRegWxpCompiledLimit &&
- heap->isolate()->memory_allocator()->SizeExecutable() >
- RegExpImpl::kRegExpExecutableMemoryLimit) {
- use_slow_safe_regexp_compiler = true;
- }
- macro_assembler->set_slow_safe(use_slow_safe_regexp_compiler);
- #ifdef DEBUG
- if (FLAG_trace_regexp_assembler)
- macro_assembler_ = new RegExpMacroAssemblerTracer(macro_assembler);
- else
- #endif
- macro_assembler_ = macro_assembler;
- List <RegExpNode*> work_list(0);
- work_list_ = &work_list;
- Label fail;
- macro_assembler_->PushBacktrack(&fail);
- Trace new_trace;
- start->Emit(this, &new_trace);
- macro_assembler_->Bind(&fail);
- macro_assembler_->Fail();
- while (!work_list.is_empty()) {
- work_list.RemoveLast()->Emit(this, &new_trace);
- }
- if (reg_exp_too_big_) return IrregexpRegExpTooBig(zone_->isolate());
- Handle<HeapObject> code = macro_assembler_->GetCode(pattern);
- heap->IncreaseTotalRegexpCodeGenerated(code->Size());
- work_list_ = NULL;
- #ifdef DEBUG
- if (FLAG_print_code) {
- CodeTracer::Scope trace_scope(heap->isolate()->GetCodeTracer());
- OFStream os(trace_scope.file());
- Handle<Code>::cast(code)->Disassemble(pattern->ToCString().get(), os);
- }
- if (FLAG_trace_regexp_assembler) {
- delete macro_assembler_;
- }
- #endif
- return RegExpEngine::CompilationResult(*code, next_register_);
- }
- bool Trace::DeferredAction::Mentions(int that) {
- if (action_type() == ActionNode::CLEAR_CAPTURES) {
- Interval range = static_cast<DeferredClearCaptures*>(this)->range();
- return range.Contains(that);
- } else {
- return reg() == that;
- }
- }
- bool Trace::mentions_reg(int reg) {
- for (DeferredAction* action = actions_;
- action != NULL;
- action = action->next()) {
- if (action->Mentions(reg))
- return true;
- }
- return false;
- }
- bool Trace::GetStoredPosition(int reg, int* cp_offset) {
- DCHECK_EQ(0, *cp_offset);
- for (DeferredAction* action = actions_;
- action != NULL;
- action = action->next()) {
- if (action->Mentions(reg)) {
- if (action->action_type() == ActionNode::STORE_POSITION) {
- *cp_offset = static_cast<DeferredCapture*>(action)->cp_offset();
- return true;
- } else {
- return false;
- }
- }
- }
- return false;
- }
- int Trace::FindAffectedRegisters(OutSet* affected_registers,
- Zone* zone) {
- int max_register = RegExpCompiler::kNoRegister;
- for (DeferredAction* action = actions_;
- action != NULL;
- action = action->next()) {
- if (action->action_type() == ActionNode::CLEAR_CAPTURES) {
- Interval range = static_cast<DeferredClearCaptures*>(action)->range();
- for (int i = range.from(); i <= range.to(); i++)
- affected_registers->Set(i, zone);
- if (range.to() > max_register) max_register = range.to();
- } else {
- affected_registers->Set(action->reg(), zone);
- if (action->reg() > max_register) max_register = action->reg();
- }
- }
- return max_register;
- }
- void Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler,
- int max_register,
- const OutSet& registers_to_pop,
- const OutSet& registers_to_clear) {
- for (int reg = max_register; reg >= 0; reg--) {
- if (registers_to_pop.Get(reg)) {
- assembler->PopRegister(reg);
- } else if (registers_to_clear.Get(reg)) {
- int clear_to = reg;
- while (reg > 0 && registers_to_clear.Get(reg - 1)) {
- reg--;
- }
- assembler->ClearRegisters(reg, clear_to);
- }
- }
- }
- void Trace::PerformDeferredActions(RegExpMacroAssembler* assembler,
- int max_register,
- const OutSet& affected_registers,
- OutSet* registers_to_pop,
- OutSet* registers_to_clear,
- Zone* zone) {
- // The "+1" is to avoid a push_limit of zero if stack_limit_slack() is 1.
- const int push_limit = (assembler->stack_limit_slack() + 1) / 2;
- // Count pushes performed to force a stack limit check occasionally.
- int pushes = 0;
- for (int reg = 0; reg <= max_register; reg++) {
- if (!affected_registers.Get(reg)) {
- continue;
- }
- // The chronologically first deferred action in the trace
- // is used to infer the action needed to restore a register
- // to its previous state (or not, if it's safe to ignore it).
- enum DeferredActionUndoType { IGNORE, RESTORE, CLEAR };
- DeferredActionUndoType undo_action = IGNORE;
- int value = 0;
- bool absolute = false;
- bool clear = false;
- int store_position = -1;
- // This is a little tricky because we are scanning the actions in reverse
- // historical order (newest first).
- for (DeferredAction* action = actions_;
- action != NULL;
- action = action->next()) {
- if (action->Mentions(reg)) {
- switch (action->action_type()) {
- case ActionNode::SET_REGISTER: {
- Trace::DeferredSetRegister* psr =
- static_cast<Trace::DeferredSetRegister*>(action);
- if (!absolute) {
- value += psr->value();
- absolute = true;
- }
- // SET_REGISTER is currently only used for newly introduced loop
- // counters. They can have a significant previous value if they
- // occour in a loop. TODO(lrn): Propagate this information, so
- // we can set undo_action to IGNORE if we know there is no value to
- // restore.
- undo_action = RESTORE;
- DCHECK_EQ(store_position, -1);
- DCHECK(!clear);
- break;
- }
- case ActionNode::INCREMENT_REGISTER:
- if (!absolute) {
- value++;
- }
- DCHECK_EQ(store_position, -1);
- DCHECK(!clear);
- undo_action = RESTORE;
- break;
- case ActionNode::STORE_POSITION: {
- Trace::DeferredCapture* pc =
- static_cast<Trace::DeferredCapture*>(action);
- if (!clear && store_position == -1) {
- store_position = pc->cp_offset();
- }
- // For captures we know that stores and clears alternate.
- // Other register, are never cleared, and if the occur
- // inside a loop, they might be assigned more than once.
- if (reg <= 1) {
- // Registers zero and one, aka "capture zero", is
- // always set correctly if we succeed. There is no
- // need to undo a setting on backtrack, because we
- // will set it again or fail.
- undo_action = IGNORE;
- } else {
- undo_action = pc->is_capture() ? CLEAR : RESTORE;
- }
- DCHECK(!absolute);
- DCHECK_EQ(value, 0);
- break;
- }
- case ActionNode::CLEAR_CAPTURES: {
- // Since we're scanning in reverse order, if we've already
- // set the position we have to ignore historically earlier
- // clearing operations.
- if (store_position == -1) {
- clear = true;
- }
- undo_action = RESTORE;
- DCHECK(!absolute);
- DCHECK_EQ(value, 0);
- break;
- }
- default:
- UNREACHABLE();
- break;
- }
- }
- }
- // Prepare for the undo-action (e.g., push if it's going to be popped).
- if (undo_action == RESTORE) {
- pushes++;
- RegExpMacroAssembler::StackCheckFlag stack_check =
- RegExpMacroAssembler::kNoStackLimitCheck;
- if (pushes == push_limit) {
- stack_check = RegExpMacroAssembler::kCheckStackLimit;
- pushes = 0;
- }
- assembler->PushRegister(reg, stack_check);
- registers_to_pop->Set(reg, zone);
- } else if (undo_action == CLEAR) {
- registers_to_clear->Set(reg, zone);
- }
- // Perform the chronologically last action (or accumulated increment)
- // for the register.
- if (store_position != -1) {
- assembler->WriteCurrentPositionToRegister(reg, store_position);
- } else if (clear) {
- assembler->ClearRegisters(reg, reg);
- } else if (absolute) {
- assembler->SetRegister(reg, value);
- } else if (value != 0) {
- assembler->AdvanceRegister(reg, value);
- }
- }
- }
- // This is called as we come into a loop choice node and some other tricky
- // nodes. It normalizes the state of the code generator to ensure we can
- // generate generic code.
- void Trace::Flush(RegExpCompiler* compiler, RegExpNode* successor) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- DCHECK(!is_trivial());
- if (actions_ == NULL && backtrack() == NULL) {
- // Here we just have some deferred cp advances to fix and we are back to
- // a normal situation. We may also have to forget some information gained
- // through a quick check that was already performed.
- if (cp_offset_ != 0) assembler->AdvanceCurrentPosition(cp_offset_);
- // Create a new trivial state and generate the node with that.
- Trace new_state;
- successor->Emit(compiler, &new_state);
- return;
- }
- // Generate deferred actions here along with code to undo them again.
- OutSet affected_registers;
- if (backtrack() != NULL) {
- // Here we have a concrete backtrack location. These are set up by choice
- // nodes and so they indicate that we have a deferred save of the current
- // position which we may need to emit here.
- assembler->PushCurrentPosition();
- }
- int max_register = FindAffectedRegisters(&affected_registers,
- compiler->zone());
- OutSet registers_to_pop;
- OutSet registers_to_clear;
- PerformDeferredActions(assembler,
- max_register,
- affected_registers,
- ®isters_to_pop,
- ®isters_to_clear,
- compiler->zone());
- if (cp_offset_ != 0) {
- assembler->AdvanceCurrentPosition(cp_offset_);
- }
- // Create a new trivial state and generate the node with that.
- Label undo;
- assembler->PushBacktrack(&undo);
- Trace new_state;
- successor->Emit(compiler, &new_state);
- // On backtrack we need to restore state.
- assembler->Bind(&undo);
- RestoreAffectedRegisters(assembler,
- max_register,
- registers_to_pop,
- registers_to_clear);
- if (backtrack() == NULL) {
- assembler->Backtrack();
- } else {
- assembler->PopCurrentPosition();
- assembler->GoTo(backtrack());
- }
- }
- void NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- // Omit flushing the trace. We discard the entire stack frame anyway.
- if (!label()->is_bound()) {
- // We are completely independent of the trace, since we ignore it,
- // so this code can be used as the generic version.
- assembler->Bind(label());
- }
- // Throw away everything on the backtrack stack since the start
- // of the negative submatch and restore the character position.
- assembler->ReadCurrentPositionFromRegister(current_position_register_);
- assembler->ReadStackPointerFromRegister(stack_pointer_register_);
- if (clear_capture_count_ > 0) {
- // Clear any captures that might have been performed during the success
- // of the body of the negative look-ahead.
- int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1;
- assembler->ClearRegisters(clear_capture_start_, clear_capture_end);
- }
- // Now that we have unwound the stack we find at the top of the stack the
- // backtrack that the BeginSubmatch node got.
- assembler->Backtrack();
- }
- void EndNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- return;
- }
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- if (!label()->is_bound()) {
- assembler->Bind(label());
- }
- switch (action_) {
- case ACCEPT:
- assembler->Succeed();
- return;
- case BACKTRACK:
- assembler->GoTo(trace->backtrack());
- return;
- case NEGATIVE_SUBMATCH_SUCCESS:
- // This case is handled in a different virtual method.
- UNREACHABLE();
- }
- UNIMPLEMENTED();
- }
- void GuardedAlternative::AddGuard(Guard* guard, Zone* zone) {
- if (guards_ == NULL)
- guards_ = new(zone) ZoneList<Guard*>(1, zone);
- guards_->Add(guard, zone);
- }
- ActionNode* ActionNode::SetRegister(int reg,
- int val,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(SET_REGISTER, on_success);
- result->data_.u_store_register.reg = reg;
- result->data_.u_store_register.value = val;
- return result;
- }
- ActionNode* ActionNode::IncrementRegister(int reg, RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(INCREMENT_REGISTER, on_success);
- result->data_.u_increment_register.reg = reg;
- return result;
- }
- ActionNode* ActionNode::StorePosition(int reg,
- bool is_capture,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(STORE_POSITION, on_success);
- result->data_.u_position_register.reg = reg;
- result->data_.u_position_register.is_capture = is_capture;
- return result;
- }
- ActionNode* ActionNode::ClearCaptures(Interval range,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(CLEAR_CAPTURES, on_success);
- result->data_.u_clear_captures.range_from = range.from();
- result->data_.u_clear_captures.range_to = range.to();
- return result;
- }
- ActionNode* ActionNode::BeginSubmatch(int stack_reg,
- int position_reg,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(BEGIN_SUBMATCH, on_success);
- result->data_.u_submatch.stack_pointer_register = stack_reg;
- result->data_.u_submatch.current_position_register = position_reg;
- return result;
- }
- ActionNode* ActionNode::PositiveSubmatchSuccess(int stack_reg,
- int position_reg,
- int clear_register_count,
- int clear_register_from,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(POSITIVE_SUBMATCH_SUCCESS, on_success);
- result->data_.u_submatch.stack_pointer_register = stack_reg;
- result->data_.u_submatch.current_position_register = position_reg;
- result->data_.u_submatch.clear_register_count = clear_register_count;
- result->data_.u_submatch.clear_register_from = clear_register_from;
- return result;
- }
- ActionNode* ActionNode::EmptyMatchCheck(int start_register,
- int repetition_register,
- int repetition_limit,
- RegExpNode* on_success) {
- ActionNode* result =
- new(on_success->zone()) ActionNode(EMPTY_MATCH_CHECK, on_success);
- result->data_.u_empty_match_check.start_register = start_register;
- result->data_.u_empty_match_check.repetition_register = repetition_register;
- result->data_.u_empty_match_check.repetition_limit = repetition_limit;
- return result;
- }
- #define DEFINE_ACCEPT(Type) \
- void Type##Node::Accept(NodeVisitor* visitor) { \
- visitor->Visit##Type(this); \
- }
- FOR_EACH_NODE_TYPE(DEFINE_ACCEPT)
- #undef DEFINE_ACCEPT
- void LoopChoiceNode::Accept(NodeVisitor* visitor) {
- visitor->VisitLoopChoice(this);
- }
- // -------------------------------------------------------------------
- // Emit code.
- void ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler,
- Guard* guard,
- Trace* trace) {
- switch (guard->op()) {
- case Guard::LT:
- DCHECK(!trace->mentions_reg(guard->reg()));
- macro_assembler->IfRegisterGE(guard->reg(),
- guard->value(),
- trace->backtrack());
- break;
- case Guard::GEQ:
- DCHECK(!trace->mentions_reg(guard->reg()));
- macro_assembler->IfRegisterLT(guard->reg(),
- guard->value(),
- trace->backtrack());
- break;
- }
- }
- // Returns the number of characters in the equivalence class, omitting those
- // that cannot occur in the source string because it is ASCII.
- static int GetCaseIndependentLetters(Isolate* isolate,
- uc16 character,
- bool ascii_subject,
- unibrow::uchar* letters) {
- int length =
- isolate->jsregexp_uncanonicalize()->get(character, '\0', letters);
- // Unibrow returns 0 or 1 for characters where case independence is
- // trivial.
- if (length == 0) {
- letters[0] = character;
- length = 1;
- }
- if (!ascii_subject || character <= String::kMaxOneByteCharCode) {
- return length;
- }
- // The standard requires that non-ASCII characters cannot have ASCII
- // character codes in their equivalence class.
- return 0;
- }
- static inline bool EmitSimpleCharacter(Isolate* isolate,
- RegExpCompiler* compiler,
- uc16 c,
- Label* on_failure,
- int cp_offset,
- bool check,
- bool preloaded) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- bool bound_checked = false;
- if (!preloaded) {
- assembler->LoadCurrentCharacter(
- cp_offset,
- on_failure,
- check);
- bound_checked = true;
- }
- assembler->CheckNotCharacter(c, on_failure);
- return bound_checked;
- }
- // Only emits non-letters (things that don't have case). Only used for case
- // independent matches.
- static inline bool EmitAtomNonLetter(Isolate* isolate,
- RegExpCompiler* compiler,
- uc16 c,
- Label* on_failure,
- int cp_offset,
- bool check,
- bool preloaded) {
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- bool ascii = compiler->ascii();
- unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- int length = GetCaseIndependentLetters(isolate, c, ascii, chars);
- if (length < 1) {
- // This can't match. Must be an ASCII subject and a non-ASCII character.
- // We do not need to do anything since the ASCII pass already handled this.
- return false; // Bounds not checked.
- }
- bool checked = false;
- // We handle the length > 1 case in a later pass.
- if (length == 1) {
- if (ascii && c > String::kMaxOneByteCharCodeU) {
- // Can't match - see above.
- return false; // Bounds not checked.
- }
- if (!preloaded) {
- macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
- checked = check;
- }
- macro_assembler->CheckNotCharacter(c, on_failure);
- }
- return checked;
- }
- static bool ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler,
- bool ascii,
- uc16 c1,
- uc16 c2,
- Label* on_failure) {
- uc16 char_mask;
- if (ascii) {
- char_mask = String::kMaxOneByteCharCode;
- } else {
- char_mask = String::kMaxUtf16CodeUnit;
- }
- uc16 exor = c1 ^ c2;
- // Check whether exor has only one bit set.
- if (((exor - 1) & exor) == 0) {
- // If c1 and c2 differ only by one bit.
- // Ecma262UnCanonicalize always gives the highest number last.
- DCHECK(c2 > c1);
- uc16 mask = char_mask ^ exor;
- macro_assembler->CheckNotCharacterAfterAnd(c1, mask, on_failure);
- return true;
- }
- DCHECK(c2 > c1);
- uc16 diff = c2 - c1;
- if (((diff - 1) & diff) == 0 && c1 >= diff) {
- // If the characters differ by 2^n but don't differ by one bit then
- // subtract the difference from the found character, then do the or
- // trick. We avoid the theoretical case where negative numbers are
- // involved in order to simplify code generation.
- uc16 mask = char_mask ^ diff;
- macro_assembler->CheckNotCharacterAfterMinusAnd(c1 - diff,
- diff,
- mask,
- on_failure);
- return true;
- }
- return false;
- }
- typedef bool EmitCharacterFunction(Isolate* isolate,
- RegExpCompiler* compiler,
- uc16 c,
- Label* on_failure,
- int cp_offset,
- bool check,
- bool preloaded);
- // Only emits letters (things that have case). Only used for case independent
- // matches.
- static inline bool EmitAtomLetter(Isolate* isolate,
- RegExpCompiler* compiler,
- uc16 c,
- Label* on_failure,
- int cp_offset,
- bool check,
- bool preloaded) {
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- bool ascii = compiler->ascii();
- unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- int length = GetCaseIndependentLetters(isolate, c, ascii, chars);
- if (length <= 1) return false;
- // We may not need to check against the end of the input string
- // if this character lies before a character that matched.
- if (!preloaded) {
- macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
- }
- Label ok;
- DCHECK(unibrow::Ecma262UnCanonicalize::kMaxWidth == 4);
- switch (length) {
- case 2: {
- if (ShortCutEmitCharacterPair(macro_assembler,
- ascii,
- chars[0],
- chars[1],
- on_failure)) {
- } else {
- macro_assembler->CheckCharacter(chars[0], &ok);
- macro_assembler->CheckNotCharacter(chars[1], on_failure);
- macro_assembler->Bind(&ok);
- }
- break;
- }
- case 4:
- macro_assembler->CheckCharacter(chars[3], &ok);
- // Fall through!
- case 3:
- macro_assembler->CheckCharacter(chars[0], &ok);
- macro_assembler->CheckCharacter(chars[1], &ok);
- macro_assembler->CheckNotCharacter(chars[2], on_failure);
- macro_assembler->Bind(&ok);
- break;
- default:
- UNREACHABLE();
- break;
- }
- return true;
- }
- static void EmitBoundaryTest(RegExpMacroAssembler* masm,
- int border,
- Label* fall_through,
- Label* above_or_equal,
- Label* below) {
- if (below != fall_through) {
- masm->CheckCharacterLT(border, below);
- if (above_or_equal != fall_through) masm->GoTo(above_or_equal);
- } else {
- masm->CheckCharacterGT(border - 1, above_or_equal);
- }
- }
- static void EmitDoubleBoundaryTest(RegExpMacroAssembler* masm,
- int first,
- int last,
- Label* fall_through,
- Label* in_range,
- Label* out_of_range) {
- if (in_range == fall_through) {
- if (first == last) {
- masm->CheckNotCharacter(first, out_of_range);
- } else {
- masm->CheckCharacterNotInRange(first, last, out_of_range);
- }
- } else {
- if (first == last) {
- masm->CheckCharacter(first, in_range);
- } else {
- masm->CheckCharacterInRange(first, last, in_range);
- }
- if (out_of_range != fall_through) masm->GoTo(out_of_range);
- }
- }
- // even_label is for ranges[i] to ranges[i + 1] where i - start_index is even.
- // odd_label is for ranges[i] to ranges[i + 1] where i - start_index is odd.
- static void EmitUseLookupTable(
- RegExpMacroAssembler* masm,
- ZoneList<int>* ranges,
- int start_index,
- int end_index,
- int min_char,
- Label* fall_through,
- Label* even_label,
- Label* odd_label) {
- static const int kSize = RegExpMacroAssembler::kTableSize;
- static const int kMask = RegExpMacroAssembler::kTableMask;
- int base = (min_char & ~kMask);
- USE(base);
- // Assert that everything is on one kTableSize page.
- for (int i = start_index; i <= end_index; i++) {
- DCHECK_EQ(ranges->at(i) & ~kMask, base);
- }
- DCHECK(start_index == 0 || (ranges->at(start_index - 1) & ~kMask) <= base);
- char templ[kSize];
- Label* on_bit_set;
- Label* on_bit_clear;
- int bit;
- if (even_label == fall_through) {
- on_bit_set = odd_label;
- on_bit_clear = even_label;
- bit = 1;
- } else {
- on_bit_set = even_label;
- on_bit_clear = odd_label;
- bit = 0;
- }
- for (int i = 0; i < (ranges->at(start_index) & kMask) && i < kSize; i++) {
- templ[i] = bit;
- }
- int j = 0;
- bit ^= 1;
- for (int i = start_index; i < end_index; i++) {
- for (j = (ranges->at(i) & kMask); j < (ranges->at(i + 1) & kMask); j++) {
- templ[j] = bit;
- }
- bit ^= 1;
- }
- for (int i = j; i < kSize; i++) {
- templ[i] = bit;
- }
- Factory* factory = masm->zone()->isolate()->factory();
- // TODO(erikcorry): Cache these.
- Handle<ByteArray> ba = factory->NewByteArray(kSize, TENURED);
- for (int i = 0; i < kSize; i++) {
- ba->set(i, templ[i]);
- }
- masm->CheckBitInTable(ba, on_bit_set);
- if (on_bit_clear != fall_through) masm->GoTo(on_bit_clear);
- }
- static void CutOutRange(RegExpMacroAssembler* masm,
- ZoneList<int>* ranges,
- int start_index,
- int end_index,
- int cut_index,
- Label* even_label,
- Label* odd_label) {
- bool odd = (((cut_index - start_index) & 1) == 1);
- Label* in_range_label = odd ? odd_label : even_label;
- Label dummy;
- EmitDoubleBoundaryTest(masm,
- ranges->at(cut_index),
- ranges->at(cut_index + 1) - 1,
- &dummy,
- in_range_label,
- &dummy);
- DCHECK(!dummy.is_linked());
- // Cut out the single range by rewriting the array. This creates a new
- // range that is a merger of the two ranges on either side of the one we
- // are cutting out. The oddity of the labels is preserved.
- for (int j = cut_index; j > start_index; j--) {
- ranges->at(j) = ranges->at(j - 1);
- }
- for (int j = cut_index + 1; j < end_index; j++) {
- ranges->at(j) = ranges->at(j + 1);
- }
- }
- // Unicode case. Split the search space into kSize spaces that are handled
- // with recursion.
- static void SplitSearchSpace(ZoneList<int>* ranges,
- int start_index,
- int end_index,
- int* new_start_index,
- int* new_end_index,
- int* border) {
- static const int kSize = RegExpMacroAssembler::kTableSize;
- static const int kMask = RegExpMacroAssembler::kTableMask;
- int first = ranges->at(start_index);
- int last = ranges->at(end_index) - 1;
- *new_start_index = start_index;
- *border = (ranges->at(start_index) & ~kMask) + kSize;
- while (*new_start_index < end_index) {
- if (ranges->at(*new_start_index) > *border) break;
- (*new_start_index)++;
- }
- // new_start_index is the index of the first edge that is beyond the
- // current kSize space.
- // For very large search spaces we do a binary chop search of the non-ASCII
- // space instead of just going to the end of the current kSize space. The
- // heuristics are complicated a little by the fact that any 128-character
- // encoding space can be quickly tested with a table lookup, so we don't
- // wish to do binary chop search at a smaller granularity than that. A
- // 128-character space can take up a lot of space in the ranges array if,
- // for example, we only want to match every second character (eg. the lower
- // case characters on some Unicode pages).
- int binary_chop_index = (end_index + start_index) / 2;
- // The first test ensures that we get to the code that handles the ASCII
- // range with a single not-taken branch, speeding up this important
- // character range (even non-ASCII charset-based text has spaces and
- // punctuation).
- if (*border - 1 > String::kMaxOneByteCharCode && // ASCII case.
- end_index - start_index > (*new_start_index - start_index) * 2 &&
- last - first > kSize * 2 &&
- binary_chop_index > *new_start_index &&
- ranges->at(binary_chop_index) >= first + 2 * kSize) {
- int scan_forward_for_section_border = binary_chop_index;;
- int new_border = (ranges->at(binary_chop_index) | kMask) + 1;
- while (scan_forward_for_section_border < end_index) {
- if (ranges->at(scan_forward_for_section_border) > new_border) {
- *new_start_index = scan_forward_for_section_border;
- *border = new_border;
- break;
- }
- scan_forward_for_section_border++;
- }
- }
- DCHECK(*new_start_index > start_index);
- *new_end_index = *new_start_index - 1;
- if (ranges->at(*new_end_index) == *border) {
- (*new_end_index)--;
- }
- if (*border >= ranges->at(end_index)) {
- *border = ranges->at(end_index);
- *new_start_index = end_index; // Won't be used.
- *new_end_index = end_index - 1;
- }
- }
- // Gets a series of segment boundaries representing a character class. If the
- // character is in the range between an even and an odd boundary (counting from
- // start_index) then go to even_label, otherwise go to odd_label. We already
- // know that the character is in the range of min_char to max_char inclusive.
- // Either label can be NULL indicating backtracking. Either label can also be
- // equal to the fall_through label.
- static void GenerateBranches(RegExpMacroAssembler* masm,
- ZoneList<int>* ranges,
- int start_index,
- int end_index,
- uc16 min_char,
- uc16 max_char,
- Label* fall_through,
- Label* even_label,
- Label* odd_label) {
- int first = ranges->at(start_index);
- int last = ranges->at(end_index) - 1;
- DCHECK_LT(min_char, first);
- // Just need to test if the character is before or on-or-after
- // a particular character.
- if (start_index == end_index) {
- EmitBoundaryTest(masm, first, fall_through, even_label, odd_label);
- return;
- }
- // Another almost trivial case: There is one interval in the middle that is
- // different from the end intervals.
- if (start_index + 1 == end_index) {
- EmitDoubleBoundaryTest(
- masm, first, last, fall_through, even_label, odd_label);
- return;
- }
- // It's not worth using table lookup if there are very few intervals in the
- // character class.
- if (end_index - start_index <= 6) {
- // It is faster to test for individual characters, so we look for those
- // first, then try arbitrary ranges in the second round.
- static int kNoCutIndex = -1;
- int cut = kNoCutIndex;
- for (int i = start_index; i < end_index; i++) {
- if (ranges->at(i) == ranges->at(i + 1) - 1) {
- cut = i;
- break;
- }
- }
- if (cut == kNoCutIndex) cut = start_index;
- CutOutRange(
- masm, ranges, start_index, end_index, cut, even_label, odd_label);
- DCHECK_GE(end_index - start_index, 2);
- GenerateBranches(masm,
- ranges,
- start_index + 1,
- end_index - 1,
- min_char,
- max_char,
- fall_through,
- even_label,
- odd_label);
- return;
- }
- // If there are a lot of intervals in the regexp, then we will use tables to
- // determine whether the character is inside or outside the character class.
- static const int kBits = RegExpMacroAssembler::kTableSizeBits;
- if ((max_char >> kBits) == (min_char >> kBits)) {
- EmitUseLookupTable(masm,
- ranges,
- start_index,
- end_index,
- min_char,
- fall_through,
- even_label,
- odd_label);
- return;
- }
- if ((min_char >> kBits) != (first >> kBits)) {
- masm->CheckCharacterLT(first, odd_label);
- GenerateBranches(masm,
- ranges,
- start_index + 1,
- end_index,
- first,
- max_char,
- fall_through,
- odd_label,
- even_label);
- return;
- }
- int new_start_index = 0;
- int new_end_index = 0;
- int border = 0;
- SplitSearchSpace(ranges,
- start_index,
- end_index,
- &new_start_index,
- &new_end_index,
- &border);
- Label handle_rest;
- Label* above = &handle_rest;
- if (border == last + 1) {
- // We didn't find any section that started after the limit, so everything
- // above the border is one of the terminal labels.
- above = (end_index & 1) != (start_index & 1) ? odd_label : even_label;
- DCHECK(new_end_index == end_index - 1);
- }
- DCHECK_LE(start_index, new_end_index);
- DCHECK_LE(new_start_index, end_index);
- DCHECK_LT(start_index, new_start_index);
- DCHECK_LT(new_end_index, end_index);
- DCHECK(new_end_index + 1 == new_start_index ||
- (new_end_index + 2 == new_start_index &&
- border == ranges->at(new_end_index + 1)));
- DCHECK_LT(min_char, border - 1);
- DCHECK_LT(border, max_char);
- DCHECK_LT(ranges->at(new_end_index), border);
- DCHECK(border < ranges->at(new_start_index) ||
- (border == ranges->at(new_start_index) &&
- new_start_index == end_index &&
- new_end_index == end_index - 1 &&
- border == last + 1));
- DCHECK(new_start_index == 0 || border >= ranges->at(new_start_index - 1));
- masm->CheckCharacterGT(border - 1, above);
- Label dummy;
- GenerateBranches(masm,
- ranges,
- start_index,
- new_end_index,
- min_char,
- border - 1,
- &dummy,
- even_label,
- odd_label);
- if (handle_rest.is_linked()) {
- masm->Bind(&handle_rest);
- bool flip = (new_start_index & 1) != (start_index & 1);
- GenerateBranches(masm,
- ranges,
- new_start_index,
- end_index,
- border,
- max_char,
- &dummy,
- flip ? odd_label : even_label,
- flip ? even_label : odd_label);
- }
- }
- static void EmitCharClass(RegExpMacroAssembler* macro_assembler,
- RegExpCharacterClass* cc,
- bool ascii,
- Label* on_failure,
- int cp_offset,
- bool check_offset,
- bool preloaded,
- Zone* zone) {
- ZoneList<CharacterRange>* ranges = cc->ranges(zone);
- if (!CharacterRange::IsCanonical(ranges)) {
- CharacterRange::Canonicalize(ranges);
- }
- int max_char;
- if (ascii) {
- max_char = String::kMaxOneByteCharCode;
- } else {
- max_char = String::kMaxUtf16CodeUnit;
- }
- int range_count = ranges->length();
- int last_valid_range = range_count - 1;
- while (last_valid_range >= 0) {
- CharacterRange& range = ranges->at(last_valid_range);
- if (range.from() <= max_char) {
- break;
- }
- last_valid_range--;
- }
- if (last_valid_range < 0) {
- if (!cc->is_negated()) {
- macro_assembler->GoTo(on_failure);
- }
- if (check_offset) {
- macro_assembler->CheckPosition(cp_offset, on_failure);
- }
- return;
- }
- if (last_valid_range == 0 &&
- ranges->at(0).IsEverything(max_char)) {
- if (cc->is_negated()) {
- macro_assembler->GoTo(on_failure);
- } else {
- // This is a common case hit by non-anchored expressions.
- if (check_offset) {
- macro_assembler->CheckPosition(cp_offset, on_failure);
- }
- }
- return;
- }
- if (last_valid_range == 0 &&
- !cc->is_negated() &&
- ranges->at(0).IsEverything(max_char)) {
- // This is a common case hit by non-anchored expressions.
- if (check_offset) {
- macro_assembler->CheckPosition(cp_offset, on_failure);
- }
- return;
- }
- if (!preloaded) {
- macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
- }
- if (cc->is_standard(zone) &&
- macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
- on_failure)) {
- return;
- }
- // A new list with ascending entries. Each entry is a code unit
- // where there is a boundary between code units that are part of
- // the class and code units that are not. Normally we insert an
- // entry at zero which goes to the failure label, but if there
- // was already one there we fall through for success on that entry.
- // Subsequent entries have alternating meaning (success/failure).
- ZoneList<int>* range_boundaries =
- new(zone) ZoneList<int>(last_valid_range, zone);
- bool zeroth_entry_is_failure = !cc->is_negated();
- for (int i = 0; i <= last_valid_range; i++) {
- CharacterRange& range = ranges->at(i);
- if (range.from() == 0) {
- DCHECK_EQ(i, 0);
- zeroth_entry_is_failure = !zeroth_entry_is_failure;
- } else {
- range_boundaries->Add(range.from(), zone);
- }
- range_boundaries->Add(range.to() + 1, zone);
- }
- int end_index = range_boundaries->length() - 1;
- if (range_boundaries->at(end_index) > max_char) {
- end_index--;
- }
- Label fall_through;
- GenerateBranches(macro_assembler,
- range_boundaries,
- 0, // start_index.
- end_index,
- 0, // min_char.
- max_char,
- &fall_through,
- zeroth_entry_is_failure ? &fall_through : on_failure,
- zeroth_entry_is_failure ? on_failure : &fall_through);
- macro_assembler->Bind(&fall_through);
- }
- RegExpNode::~RegExpNode() {
- }
- RegExpNode::LimitResult RegExpNode::LimitVersions(RegExpCompiler* compiler,
- Trace* trace) {
- // If we are generating a greedy loop then don't stop and don't reuse code.
- if (trace->stop_node() != NULL) {
- return CONTINUE;
- }
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- if (trace->is_trivial()) {
- if (label_.is_bound()) {
- // We are being asked to generate a generic version, but that's already
- // been done so just go to it.
- macro_assembler->GoTo(&label_);
- return DONE;
- }
- if (compiler->recursion_depth() >= RegExpCompiler::kMaxRecursion) {
- // To avoid too deep recursion we push the node to the work queue and just
- // generate a goto here.
- compiler->AddWork(this);
- macro_assembler->GoTo(&label_);
- return DONE;
- }
- // Generate generic version of the node and bind the label for later use.
- macro_assembler->Bind(&label_);
- return CONTINUE;
- }
- // We are being asked to make a non-generic version. Keep track of how many
- // non-generic versions we generate so as not to overdo it.
- trace_count_++;
- if (FLAG_regexp_optimization &&
- trace_count_ < kMaxCopiesCodeGenerated &&
- compiler->recursion_depth() <= RegExpCompiler::kMaxRecursion) {
- return CONTINUE;
- }
- // If we get here code has been generated for this node too many times or
- // recursion is too deep. Time to switch to a generic version. The code for
- // generic versions above can handle deep recursion properly.
- trace->Flush(compiler, this);
- return DONE;
- }
- int ActionNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- if (budget <= 0) return 0;
- if (action_type_ == POSITIVE_SUBMATCH_SUCCESS) return 0; // Rewinds input!
- return on_success()->EatsAtLeast(still_to_find,
- budget - 1,
- not_at_start);
- }
- void ActionNode::FillInBMInfo(int offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- if (action_type_ == BEGIN_SUBMATCH) {
- bm->SetRest(offset);
- } else if (action_type_ != POSITIVE_SUBMATCH_SUCCESS) {
- on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start);
- }
- SaveBMInfo(bm, not_at_start, offset);
- }
- int AssertionNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- if (budget <= 0) return 0;
- // If we know we are not at the start and we are asked "how many characters
- // will you match if you succeed?" then we can answer anything since false
- // implies false. So lets just return the max answer (still_to_find) since
- // that won't prevent us from preloading a lot of characters for the other
- // branches in the node graph.
- if (assertion_type() == AT_START && not_at_start) return still_to_find;
- return on_success()->EatsAtLeast(still_to_find,
- budget - 1,
- not_at_start);
- }
- void AssertionNode::FillInBMInfo(int offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- // Match the behaviour of EatsAtLeast on this node.
- if (assertion_type() == AT_START && not_at_start) return;
- on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start);
- SaveBMInfo(bm, not_at_start, offset);
- }
- int BackReferenceNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- if (budget <= 0) return 0;
- return on_success()->EatsAtLeast(still_to_find,
- budget - 1,
- not_at_start);
- }
- int TextNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- int answer = Length();
- if (answer >= still_to_find) return answer;
- if (budget <= 0) return answer;
- // We are not at start after this node so we set the last argument to 'true'.
- return answer + on_success()->EatsAtLeast(still_to_find - answer,
- budget - 1,
- true);
- }
- int NegativeLookaheadChoiceNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- if (budget <= 0) return 0;
- // Alternative 0 is the negative lookahead, alternative 1 is what comes
- // afterwards.
- RegExpNode* node = alternatives_->at(1).node();
- return node->EatsAtLeast(still_to_find, budget - 1, not_at_start);
- }
- void NegativeLookaheadChoiceNode::GetQuickCheckDetails(
- QuickCheckDetails* details,
- RegExpCompiler* compiler,
- int filled_in,
- bool not_at_start) {
- // Alternative 0 is the negative lookahead, alternative 1 is what comes
- // afterwards.
- RegExpNode* node = alternatives_->at(1).node();
- return node->GetQuickCheckDetails(details, compiler, filled_in, not_at_start);
- }
- int ChoiceNode::EatsAtLeastHelper(int still_to_find,
- int budget,
- RegExpNode* ignore_this_node,
- bool not_at_start) {
- if (budget <= 0) return 0;
- int min = 100;
- int choice_count = alternatives_->length();
- budget = (budget - 1) / choice_count;
- for (int i = 0; i < choice_count; i++) {
- RegExpNode* node = alternatives_->at(i).node();
- if (node == ignore_this_node) continue;
- int node_eats_at_least =
- node->EatsAtLeast(still_to_find, budget, not_at_start);
- if (node_eats_at_least < min) min = node_eats_at_least;
- if (min == 0) return 0;
- }
- return min;
- }
- int LoopChoiceNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- return EatsAtLeastHelper(still_to_find,
- budget - 1,
- loop_node_,
- not_at_start);
- }
- int ChoiceNode::EatsAtLeast(int still_to_find,
- int budget,
- bool not_at_start) {
- return EatsAtLeastHelper(still_to_find,
- budget,
- NULL,
- not_at_start);
- }
- // Takes the left-most 1-bit and smears it out, setting all bits to its right.
- static inline uint32_t SmearBitsRight(uint32_t v) {
- v |= v >> 1;
- v |= v >> 2;
- v |= v >> 4;
- v |= v >> 8;
- v |= v >> 16;
- return v;
- }
- bool QuickCheckDetails::Rationalize(bool asc) {
- bool found_useful_op = false;
- uint32_t char_mask;
- if (asc) {
- char_mask = String::kMaxOneByteCharCode;
- } else {
- char_mask = String::kMaxUtf16CodeUnit;
- }
- mask_ = 0;
- value_ = 0;
- int char_shift = 0;
- for (int i = 0; i < characters_; i++) {
- Position* pos = &positions_[i];
- if ((pos->mask & String::kMaxOneByteCharCode) != 0) {
- found_useful_op = true;
- }
- mask_ |= (pos->mask & char_mask) << char_shift;
- value_ |= (pos->value & char_mask) << char_shift;
- char_shift += asc ? 8 : 16;
- }
- return found_useful_op;
- }
- bool RegExpNode::EmitQuickCheck(RegExpCompiler* compiler,
- Trace* trace,
- bool preload_has_checked_bounds,
- Label* on_possible_success,
- QuickCheckDetails* details,
- bool fall_through_on_failure) {
- if (details->characters() == 0) return false;
- GetQuickCheckDetails(
- details, compiler, 0, trace->at_start() == Trace::FALSE_VALUE);
- if (details->cannot_match()) return false;
- if (!details->Rationalize(compiler->ascii())) return false;
- DCHECK(details->characters() == 1 ||
- compiler->macro_assembler()->CanReadUnaligned());
- uint32_t mask = details->mask();
- uint32_t value = details->value();
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- if (trace->characters_preloaded() != details->characters()) {
- assembler->LoadCurrentCharacter(trace->cp_offset(),
- trace->backtrack(),
- !preload_has_checked_bounds,
- details->characters());
- }
- bool need_mask = true;
- if (details->characters() == 1) {
- // If number of characters preloaded is 1 then we used a byte or 16 bit
- // load so the value is already masked down.
- uint32_t char_mask;
- if (compiler->ascii()) {
- char_mask = String::kMaxOneByteCharCode;
- } else {
- char_mask = String::kMaxUtf16CodeUnit;
- }
- if ((mask & char_mask) == char_mask) need_mask = false;
- mask &= char_mask;
- } else {
- // For 2-character preloads in ASCII mode or 1-character preloads in
- // TWO_BYTE mode we also use a 16 bit load with zero extend.
- if (details->characters() == 2 && compiler->ascii()) {
- if ((mask & 0xffff) == 0xffff) need_mask = false;
- } else if (details->characters() == 1 && !compiler->ascii()) {
- if ((mask & 0xffff) == 0xffff) need_mask = false;
- } else {
- if (mask == 0xffffffff) need_mask = false;
- }
- }
- if (fall_through_on_failure) {
- if (need_mask) {
- assembler->CheckCharacterAfterAnd(value, mask, on_possible_success);
- } else {
- assembler->CheckCharacter(value, on_possible_success);
- }
- } else {
- if (need_mask) {
- assembler->CheckNotCharacterAfterAnd(value, mask, trace->backtrack());
- } else {
- assembler->CheckNotCharacter(value, trace->backtrack());
- }
- }
- return true;
- }
- // Here is the meat of GetQuickCheckDetails (see also the comment on the
- // super-class in the .h file).
- //
- // We iterate along the text object, building up for each character a
- // mask and value that can be used to test for a quick failure to match.
- // The masks and values for the positions will be combined into a single
- // machine word for the current character width in order to be used in
- // generating a quick check.
- void TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
- RegExpCompiler* compiler,
- int characters_filled_in,
- bool not_at_start) {
- Isolate* isolate = compiler->macro_assembler()->zone()->isolate();
- DCHECK(characters_filled_in < details->characters());
- int characters = details->characters();
- int char_mask;
- if (compiler->ascii()) {
- char_mask = String::kMaxOneByteCharCode;
- } else {
- char_mask = String::kMaxUtf16CodeUnit;
- }
- for (int k = 0; k < elms_->length(); k++) {
- TextElement elm = elms_->at(k);
- if (elm.text_type() == TextElement::ATOM) {
- Vector<const uc16> quarks = elm.atom()->data();
- for (int i = 0; i < characters && i < quarks.length(); i++) {
- QuickCheckDetails::Position* pos =
- details->positions(characters_filled_in);
- uc16 c = quarks[i];
- if (c > char_mask) {
- // If we expect a non-ASCII character from an ASCII string,
- // there is no way we can match. Not even case independent
- // matching can turn an ASCII character into non-ASCII or
- // vice versa.
- details->set_cannot_match();
- pos->determines_perfectly = false;
- return;
- }
- if (compiler->ignore_case()) {
- unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- int length = GetCaseIndependentLetters(isolate, c, compiler->ascii(),
- chars);
- DCHECK(length != 0); // Can only happen if c > char_mask (see above).
- if (length == 1) {
- // This letter has no case equivalents, so it's nice and simple
- // and the mask-compare will determine definitely whether we have
- // a match at this character position.
- pos->mask = char_mask;
- pos->value = c;
- pos->determines_perfectly = true;
- } else {
- uint32_t common_bits = char_mask;
- uint32_t bits = chars[0];
- for (int j = 1; j < length; j++) {
- uint32_t differing_bits = ((chars[j] & common_bits) ^ bits);
- common_bits ^= differing_bits;
- bits &= common_bits;
- }
- // If length is 2 and common bits has only one zero in it then
- // our mask and compare instruction will determine definitely
- // whether we have a match at this character position. Otherwise
- // it can only be an approximate check.
- uint32_t one_zero = (common_bits | ~char_mask);
- if (length == 2 && ((~one_zero) & ((~one_zero) - 1)) == 0) {
- pos->determines_perfectly = true;
- }
- pos->mask = common_bits;
- pos->value = bits;
- }
- } else {
- // Don't ignore case. Nice simple case where the mask-compare will
- // determine definitely whether we have a match at this character
- // position.
- pos->mask = char_mask;
- pos->value = c;
- pos->determines_perfectly = true;
- }
- characters_filled_in++;
- DCHECK(characters_filled_in <= details->characters());
- if (characters_filled_in == details->characters()) {
- return;
- }
- }
- } else {
- QuickCheckDetails::Position* pos =
- details->positions(characters_filled_in);
- RegExpCharacterClass* tree = elm.char_class();
- ZoneList<CharacterRange>* ranges = tree->ranges(zone());
- if (tree->is_negated()) {
- // A quick check uses multi-character mask and compare. There is no
- // useful way to incorporate a negative char class into this scheme
- // so we just conservatively create a mask and value that will always
- // succeed.
- pos->mask = 0;
- pos->value = 0;
- } else {
- int first_range = 0;
- while (ranges->at(first_range).from() > char_mask) {
- first_range++;
- if (first_range == ranges->length()) {
- details->set_cannot_match();
- pos->determines_perfectly = false;
- return;
- }
- }
- CharacterRange range = ranges->at(first_range);
- uc16 from = range.from();
- uc16 to = range.to();
- if (to > char_mask) {
- to = char_mask;
- }
- uint32_t differing_bits = (from ^ to);
- // A mask and compare is only perfect if the differing bits form a
- // number like 00011111 with one single block of trailing 1s.
- if ((differing_bits & (differing_bits + 1)) == 0 &&
- from + differing_bits == to) {
- pos->determines_perfectly = true;
- }
- uint32_t common_bits = ~SmearBitsRight(differing_bits);
- uint32_t bits = (from & common_bits);
- for (int i = first_range + 1; i < ranges->length(); i++) {
- CharacterRange range = ranges->at(i);
- uc16 from = range.from();
- uc16 to = range.to();
- if (from > char_mask) continue;
- if (to > char_mask) to = char_mask;
- // Here we are combining more ranges into the mask and compare
- // value. With each new range the mask becomes more sparse and
- // so the chances of a false positive rise. A character class
- // with multiple ranges is assumed never to be equivalent to a
- // mask and compare operation.
- pos->determines_perfectly = false;
- uint32_t new_common_bits = (from ^ to);
- new_common_bits = ~SmearBitsRight(new_common_bits);
- common_bits &= new_common_bits;
- bits &= new_common_bits;
- uint32_t differing_bits = (from & common_bits) ^ bits;
- common_bits ^= differing_bits;
- bits &= common_bits;
- }
- pos->mask = common_bits;
- pos->value = bits;
- }
- characters_filled_in++;
- DCHECK(characters_filled_in <= details->characters());
- if (characters_filled_in == details->characters()) {
- return;
- }
- }
- }
- DCHECK(characters_filled_in != details->characters());
- if (!details->cannot_match()) {
- on_success()-> GetQuickCheckDetails(details,
- compiler,
- characters_filled_in,
- true);
- }
- }
- void QuickCheckDetails::Clear() {
- for (int i = 0; i < characters_; i++) {
- positions_[i].mask = 0;
- positions_[i].value = 0;
- positions_[i].determines_perfectly = false;
- }
- characters_ = 0;
- }
- void QuickCheckDetails::Advance(int by, bool ascii) {
- DCHECK(by >= 0);
- if (by >= characters_) {
- Clear();
- return;
- }
- for (int i = 0; i < characters_ - by; i++) {
- positions_[i] = positions_[by + i];
- }
- for (int i = characters_ - by; i < characters_; i++) {
- positions_[i].mask = 0;
- positions_[i].value = 0;
- positions_[i].determines_perfectly = false;
- }
- characters_ -= by;
- // We could change mask_ and value_ here but we would never advance unless
- // they had already been used in a check and they won't be used again because
- // it would gain us nothing. So there's no point.
- }
- void QuickCheckDetails::Merge(QuickCheckDetails* other, int from_index) {
- DCHECK(characters_ == other->characters_);
- if (other->cannot_match_) {
- return;
- }
- if (cannot_match_) {
- *this = *other;
- return;
- }
- for (int i = from_index; i < characters_; i++) {
- QuickCheckDetails::Position* pos = positions(i);
- QuickCheckDetails::Position* other_pos = other->positions(i);
- if (pos->mask != other_pos->mask ||
- pos->value != other_pos->value ||
- !other_pos->determines_perfectly) {
- // Our mask-compare operation will be approximate unless we have the
- // exact same operation on both sides of the alternation.
- pos->determines_perfectly = false;
- }
- pos->mask &= other_pos->mask;
- pos->value &= pos->mask;
- other_pos->value &= pos->mask;
- uc16 differing_bits = (pos->value ^ other_pos->value);
- pos->mask &= ~differing_bits;
- pos->value &= pos->mask;
- }
- }
- class VisitMarker {
- public:
- explicit VisitMarker(NodeInfo* info) : info_(info) {
- DCHECK(!info->visited);
- info->visited = true;
- }
- ~VisitMarker() {
- info_->visited = false;
- }
- private:
- NodeInfo* info_;
- };
- RegExpNode* SeqRegExpNode::FilterASCII(int depth, bool ignore_case) {
- if (info()->replacement_calculated) return replacement();
- if (depth < 0) return this;
- DCHECK(!info()->visited);
- VisitMarker marker(info());
- return FilterSuccessor(depth - 1, ignore_case);
- }
- RegExpNode* SeqRegExpNode::FilterSuccessor(int depth, bool ignore_case) {
- RegExpNode* next = on_success_->FilterASCII(depth - 1, ignore_case);
- if (next == NULL) return set_replacement(NULL);
- on_success_ = next;
- return set_replacement(this);
- }
- // We need to check for the following characters: 0x39c 0x3bc 0x178.
- static inline bool RangeContainsLatin1Equivalents(CharacterRange range) {
- // TODO(dcarney): this could be a lot more efficient.
- return range.Contains(0x39c) ||
- range.Contains(0x3bc) || range.Contains(0x178);
- }
- static bool RangesContainLatin1Equivalents(ZoneList<CharacterRange>* ranges) {
- for (int i = 0; i < ranges->length(); i++) {
- // TODO(dcarney): this could be a lot more efficient.
- if (RangeContainsLatin1Equivalents(ranges->at(i))) return true;
- }
- return false;
- }
- RegExpNode* TextNode::FilterASCII(int depth, bool ignore_case) {
- if (info()->replacement_calculated) return replacement();
- if (depth < 0) return this;
- DCHECK(!info()->visited);
- VisitMarker marker(info());
- int element_count = elms_->length();
- for (int i = 0; i < element_count; i++) {
- TextElement elm = elms_->at(i);
- if (elm.text_type() == TextElement::ATOM) {
- Vector<const uc16> quarks = elm.atom()->data();
- for (int j = 0; j < quarks.length(); j++) {
- uint16_t c = quarks[j];
- if (c <= String::kMaxOneByteCharCode) continue;
- if (!ignore_case) return set_replacement(NULL);
- // Here, we need to check for characters whose upper and lower cases
- // are outside the Latin-1 range.
- uint16_t converted = unibrow::Latin1::ConvertNonLatin1ToLatin1(c);
- // Character is outside Latin-1 completely
- if (converted == 0) return set_replacement(NULL);
- // Convert quark to Latin-1 in place.
- uint16_t* copy = const_cast<uint16_t*>(quarks.start());
- copy[j] = converted;
- }
- } else {
- DCHECK(elm.text_type() == TextElement::CHAR_CLASS);
- RegExpCharacterClass* cc = elm.char_class();
- ZoneList<CharacterRange>* ranges = cc->ranges(zone());
- if (!CharacterRange::IsCanonical(ranges)) {
- CharacterRange::Canonicalize(ranges);
- }
- // Now they are in order so we only need to look at the first.
- int range_count = ranges->length();
- if (cc->is_negated()) {
- if (range_count != 0 &&
- ranges->at(0).from() == 0 &&
- ranges->at(0).to() >= String::kMaxOneByteCharCode) {
- // This will be handled in a later filter.
- if (ignore_case && RangesContainLatin1Equivalents(ranges)) continue;
- return set_replacement(NULL);
- }
- } else {
- if (range_count == 0 ||
- ranges->at(0).from() > String::kMaxOneByteCharCode) {
- // This will be handled in a later filter.
- if (ignore_case && RangesContainLatin1Equivalents(ranges)) continue;
- return set_replacement(NULL);
- }
- }
- }
- }
- return FilterSuccessor(depth - 1, ignore_case);
- }
- RegExpNode* LoopChoiceNode::FilterASCII(int depth, bool ignore_case) {
- if (info()->replacement_calculated) return replacement();
- if (depth < 0) return this;
- if (info()->visited) return this;
- {
- VisitMarker marker(info());
- RegExpNode* continue_replacement =
- continue_node_->FilterASCII(depth - 1, ignore_case);
- // If we can't continue after the loop then there is no sense in doing the
- // loop.
- if (continue_replacement == NULL) return set_replacement(NULL);
- }
- return ChoiceNode::FilterASCII(depth - 1, ignore_case);
- }
- RegExpNode* ChoiceNode::FilterASCII(int depth, bool ignore_case) {
- if (info()->replacement_calculated) return replacement();
- if (depth < 0) return this;
- if (info()->visited) return this;
- VisitMarker marker(info());
- int choice_count = alternatives_->length();
- for (int i = 0; i < choice_count; i++) {
- GuardedAlternative alternative = alternatives_->at(i);
- if (alternative.guards() != NULL && alternative.guards()->length() != 0) {
- set_replacement(this);
- return this;
- }
- }
- int surviving = 0;
- RegExpNode* survivor = NULL;
- for (int i = 0; i < choice_count; i++) {
- GuardedAlternative alternative = alternatives_->at(i);
- RegExpNode* replacement =
- alternative.node()->FilterASCII(depth - 1, ignore_case);
- DCHECK(replacement != this); // No missing EMPTY_MATCH_CHECK.
- if (replacement != NULL) {
- alternatives_->at(i).set_node(replacement);
- surviving++;
- survivor = replacement;
- }
- }
- if (surviving < 2) return set_replacement(survivor);
- set_replacement(this);
- if (surviving == choice_count) {
- return this;
- }
- // Only some of the nodes survived the filtering. We need to rebuild the
- // alternatives list.
- ZoneList<GuardedAlternative>* new_alternatives =
- new(zone()) ZoneList<GuardedAlternative>(surviving, zone());
- for (int i = 0; i < choice_count; i++) {
- RegExpNode* replacement =
- alternatives_->at(i).node()->FilterASCII(depth - 1, ignore_case);
- if (replacement != NULL) {
- alternatives_->at(i).set_node(replacement);
- new_alternatives->Add(alternatives_->at(i), zone());
- }
- }
- alternatives_ = new_alternatives;
- return this;
- }
- RegExpNode* NegativeLookaheadChoiceNode::FilterASCII(int depth,
- bool ignore_case) {
- if (info()->replacement_calculated) return replacement();
- if (depth < 0) return this;
- if (info()->visited) return this;
- VisitMarker marker(info());
- // Alternative 0 is the negative lookahead, alternative 1 is what comes
- // afterwards.
- RegExpNode* node = alternatives_->at(1).node();
- RegExpNode* replacement = node->FilterASCII(depth - 1, ignore_case);
- if (replacement == NULL) return set_replacement(NULL);
- alternatives_->at(1).set_node(replacement);
- RegExpNode* neg_node = alternatives_->at(0).node();
- RegExpNode* neg_replacement = neg_node->FilterASCII(depth - 1, ignore_case);
- // If the negative lookahead is always going to fail then
- // we don't need to check it.
- if (neg_replacement == NULL) return set_replacement(replacement);
- alternatives_->at(0).set_node(neg_replacement);
- return set_replacement(this);
- }
- void LoopChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
- RegExpCompiler* compiler,
- int characters_filled_in,
- bool not_at_start) {
- if (body_can_be_zero_length_ || info()->visited) return;
- VisitMarker marker(info());
- return ChoiceNode::GetQuickCheckDetails(details,
- compiler,
- characters_filled_in,
- not_at_start);
- }
- void LoopChoiceNode::FillInBMInfo(int offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- if (body_can_be_zero_length_ || budget <= 0) {
- bm->SetRest(offset);
- SaveBMInfo(bm, not_at_start, offset);
- return;
- }
- ChoiceNode::FillInBMInfo(offset, budget - 1, bm, not_at_start);
- SaveBMInfo(bm, not_at_start, offset);
- }
- void ChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
- RegExpCompiler* compiler,
- int characters_filled_in,
- bool not_at_start) {
- not_at_start = (not_at_start || not_at_start_);
- int choice_count = alternatives_->length();
- DCHECK(choice_count > 0);
- alternatives_->at(0).node()->GetQuickCheckDetails(details,
- compiler,
- characters_filled_in,
- not_at_start);
- for (int i = 1; i < choice_count; i++) {
- QuickCheckDetails new_details(details->characters());
- RegExpNode* node = alternatives_->at(i).node();
- node->GetQuickCheckDetails(&new_details, compiler,
- characters_filled_in,
- not_at_start);
- // Here we merge the quick match details of the two branches.
- details->Merge(&new_details, characters_filled_in);
- }
- }
- // Check for [0-9A-Z_a-z].
- static void EmitWordCheck(RegExpMacroAssembler* assembler,
- Label* word,
- Label* non_word,
- bool fall_through_on_word) {
- if (assembler->CheckSpecialCharacterClass(
- fall_through_on_word ? 'w' : 'W',
- fall_through_on_word ? non_word : word)) {
- // Optimized implementation available.
- return;
- }
- assembler->CheckCharacterGT('z', non_word);
- assembler->CheckCharacterLT('0', non_word);
- assembler->CheckCharacterGT('a' - 1, word);
- assembler->CheckCharacterLT('9' + 1, word);
- assembler->CheckCharacterLT('A', non_word);
- assembler->CheckCharacterLT('Z' + 1, word);
- if (fall_through_on_word) {
- assembler->CheckNotCharacter('_', non_word);
- } else {
- assembler->CheckCharacter('_', word);
- }
- }
- // Emit the code to check for a ^ in multiline mode (1-character lookbehind
- // that matches newline or the start of input).
- static void EmitHat(RegExpCompiler* compiler,
- RegExpNode* on_success,
- Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- // We will be loading the previous character into the current character
- // register.
- Trace new_trace(*trace);
- new_trace.InvalidateCurrentCharacter();
- Label ok;
- if (new_trace.cp_offset() == 0) {
- // The start of input counts as a newline in this context, so skip to
- // ok if we are at the start.
- assembler->CheckAtStart(&ok);
- }
- // We already checked that we are not at the start of input so it must be
- // OK to load the previous character.
- assembler->LoadCurrentCharacter(new_trace.cp_offset() -1,
- new_trace.backtrack(),
- false);
- if (!assembler->CheckSpecialCharacterClass('n',
- new_trace.backtrack())) {
- // Newline means \n, \r, 0x2028 or 0x2029.
- if (!compiler->ascii()) {
- assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
- }
- assembler->CheckCharacter('\n', &ok);
- assembler->CheckNotCharacter('\r', new_trace.backtrack());
- }
- assembler->Bind(&ok);
- on_success->Emit(compiler, &new_trace);
- }
- // Emit the code to handle \b and \B (word-boundary or non-word-boundary).
- void AssertionNode::EmitBoundaryCheck(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- Trace::TriBool next_is_word_character = Trace::UNKNOWN;
- bool not_at_start = (trace->at_start() == Trace::FALSE_VALUE);
- BoyerMooreLookahead* lookahead = bm_info(not_at_start);
- if (lookahead == NULL) {
- int eats_at_least =
- Min(kMaxLookaheadForBoyerMoore, EatsAtLeast(kMaxLookaheadForBoyerMoore,
- kRecursionBudget,
- not_at_start));
- if (eats_at_least >= 1) {
- BoyerMooreLookahead* bm =
- new(zone()) BoyerMooreLookahead(eats_at_least, compiler, zone());
- FillInBMInfo(0, kRecursionBudget, bm, not_at_start);
- if (bm->at(0)->is_non_word())
- next_is_word_character = Trace::FALSE_VALUE;
- if (bm->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE;
- }
- } else {
- if (lookahead->at(0)->is_non_word())
- next_is_word_character = Trace::FALSE_VALUE;
- if (lookahead->at(0)->is_word())
- next_is_word_character = Trace::TRUE_VALUE;
- }
- bool at_boundary = (assertion_type_ == AssertionNode::AT_BOUNDARY);
- if (next_is_word_character == Trace::UNKNOWN) {
- Label before_non_word;
- Label before_word;
- if (trace->characters_preloaded() != 1) {
- assembler->LoadCurrentCharacter(trace->cp_offset(), &before_non_word);
- }
- // Fall through on non-word.
- EmitWordCheck(assembler, &before_word, &before_non_word, false);
- // Next character is not a word character.
- assembler->Bind(&before_non_word);
- Label ok;
- BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
- assembler->GoTo(&ok);
- assembler->Bind(&before_word);
- BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
- assembler->Bind(&ok);
- } else if (next_is_word_character == Trace::TRUE_VALUE) {
- BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
- } else {
- DCHECK(next_is_word_character == Trace::FALSE_VALUE);
- BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
- }
- }
- void AssertionNode::BacktrackIfPrevious(
- RegExpCompiler* compiler,
- Trace* trace,
- AssertionNode::IfPrevious backtrack_if_previous) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- Trace new_trace(*trace);
- new_trace.InvalidateCurrentCharacter();
- Label fall_through, dummy;
- Label* non_word = backtrack_if_previous == kIsNonWord ?
- new_trace.backtrack() :
- &fall_through;
- Label* word = backtrack_if_previous == kIsNonWord ?
- &fall_through :
- new_trace.backtrack();
- if (new_trace.cp_offset() == 0) {
- // The start of input counts as a non-word character, so the question is
- // decided if we are at the start.
- assembler->CheckAtStart(non_word);
- }
- // We already checked that we are not at the start of input so it must be
- // OK to load the previous character.
- assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, &dummy, false);
- EmitWordCheck(assembler, word, non_word, backtrack_if_previous == kIsNonWord);
- assembler->Bind(&fall_through);
- on_success()->Emit(compiler, &new_trace);
- }
- void AssertionNode::GetQuickCheckDetails(QuickCheckDetails* details,
- RegExpCompiler* compiler,
- int filled_in,
- bool not_at_start) {
- if (assertion_type_ == AT_START && not_at_start) {
- details->set_cannot_match();
- return;
- }
- return on_success()->GetQuickCheckDetails(details,
- compiler,
- filled_in,
- not_at_start);
- }
- void AssertionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- switch (assertion_type_) {
- case AT_END: {
- Label ok;
- assembler->CheckPosition(trace->cp_offset(), &ok);
- assembler->GoTo(trace->backtrack());
- assembler->Bind(&ok);
- break;
- }
- case AT_START: {
- if (trace->at_start() == Trace::FALSE_VALUE) {
- assembler->GoTo(trace->backtrack());
- return;
- }
- if (trace->at_start() == Trace::UNKNOWN) {
- assembler->CheckNotAtStart(trace->backtrack());
- Trace at_start_trace = *trace;
- at_start_trace.set_at_start(true);
- on_success()->Emit(compiler, &at_start_trace);
- return;
- }
- }
- break;
- case AFTER_NEWLINE:
- EmitHat(compiler, on_success(), trace);
- return;
- case AT_BOUNDARY:
- case AT_NON_BOUNDARY: {
- EmitBoundaryCheck(compiler, trace);
- return;
- }
- }
- on_success()->Emit(compiler, trace);
- }
- static bool DeterminedAlready(QuickCheckDetails* quick_check, int offset) {
- if (quick_check == NULL) return false;
- if (offset >= quick_check->characters()) return false;
- return quick_check->positions(offset)->determines_perfectly;
- }
- static void UpdateBoundsCheck(int index, int* checked_up_to) {
- if (index > *checked_up_to) {
- *checked_up_to = index;
- }
- }
- // We call this repeatedly to generate code for each pass over the text node.
- // The passes are in increasing order of difficulty because we hope one
- // of the first passes will fail in which case we are saved the work of the
- // later passes. for example for the case independent regexp /%[asdfghjkl]a/
- // we will check the '%' in the first pass, the case independent 'a' in the
- // second pass and the character class in the last pass.
- //
- // The passes are done from right to left, so for example to test for /bar/
- // we will first test for an 'r' with offset 2, then an 'a' with offset 1
- // and then a 'b' with offset 0. This means we can avoid the end-of-input
- // bounds check most of the time. In the example we only need to check for
- // end-of-input when loading the putative 'r'.
- //
- // A slight complication involves the fact that the first character may already
- // be fetched into a register by the previous node. In this case we want to
- // do the test for that character first. We do this in separate passes. The
- // 'preloaded' argument indicates that we are doing such a 'pass'. If such a
- // pass has been performed then subsequent passes will have true in
- // first_element_checked to indicate that that character does not need to be
- // checked again.
- //
- // In addition to all this we are passed a Trace, which can
- // contain an AlternativeGeneration object. In this AlternativeGeneration
- // object we can see details of any quick check that was already passed in
- // order to get to the code we are now generating. The quick check can involve
- // loading characters, which means we do not need to recheck the bounds
- // up to the limit the quick check already checked. In addition the quick
- // check can have involved a mask and compare operation which may simplify
- // or obviate the need for further checks at some character positions.
- void TextNode::TextEmitPass(RegExpCompiler* compiler,
- TextEmitPassType pass,
- bool preloaded,
- Trace* trace,
- bool first_element_checked,
- int* checked_up_to) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- Isolate* isolate = assembler->zone()->isolate();
- bool ascii = compiler->ascii();
- Label* backtrack = trace->backtrack();
- QuickCheckDetails* quick_check = trace->quick_check_performed();
- int element_count = elms_->length();
- for (int i = preloaded ? 0 : element_count - 1; i >= 0; i--) {
- TextElement elm = elms_->at(i);
- int cp_offset = trace->cp_offset() + elm.cp_offset();
- if (elm.text_type() == TextElement::ATOM) {
- Vector<const uc16> quarks = elm.atom()->data();
- for (int j = preloaded ? 0 : quarks.length() - 1; j >= 0; j--) {
- if (first_element_checked && i == 0 && j == 0) continue;
- if (DeterminedAlready(quick_check, elm.cp_offset() + j)) continue;
- EmitCharacterFunction* emit_function = NULL;
- switch (pass) {
- case NON_ASCII_MATCH:
- DCHECK(ascii);
- if (quarks[j] > String::kMaxOneByteCharCode) {
- assembler->GoTo(backtrack);
- return;
- }
- break;
- case NON_LETTER_CHARACTER_MATCH:
- emit_function = &EmitAtomNonLetter;
- break;
- case SIMPLE_CHARACTER_MATCH:
- emit_function = &EmitSimpleCharacter;
- break;
- case CASE_CHARACTER_MATCH:
- emit_function = &EmitAtomLetter;
- break;
- default:
- break;
- }
- if (emit_function != NULL) {
- bool bound_checked = emit_function(isolate,
- compiler,
- quarks[j],
- backtrack,
- cp_offset + j,
- *checked_up_to < cp_offset + j,
- preloaded);
- if (bound_checked) UpdateBoundsCheck(cp_offset + j, checked_up_to);
- }
- }
- } else {
- DCHECK_EQ(TextElement::CHAR_CLASS, elm.text_type());
- if (pass == CHARACTER_CLASS_MATCH) {
- if (first_element_checked && i == 0) continue;
- if (DeterminedAlready(quick_check, elm.cp_offset())) continue;
- RegExpCharacterClass* cc = elm.char_class();
- EmitCharClass(assembler,
- cc,
- ascii,
- backtrack,
- cp_offset,
- *checked_up_to < cp_offset,
- preloaded,
- zone());
- UpdateBoundsCheck(cp_offset, checked_up_to);
- }
- }
- }
- }
- int TextNode::Length() {
- TextElement elm = elms_->last();
- DCHECK(elm.cp_offset() >= 0);
- return elm.cp_offset() + elm.length();
- }
- bool TextNode::SkipPass(int int_pass, bool ignore_case) {
- TextEmitPassType pass = static_cast<TextEmitPassType>(int_pass);
- if (ignore_case) {
- return pass == SIMPLE_CHARACTER_MATCH;
- } else {
- return pass == NON_LETTER_CHARACTER_MATCH || pass == CASE_CHARACTER_MATCH;
- }
- }
- // This generates the code to match a text node. A text node can contain
- // straight character sequences (possibly to be matched in a case-independent
- // way) and character classes. For efficiency we do not do this in a single
- // pass from left to right. Instead we pass over the text node several times,
- // emitting code for some character positions every time. See the comment on
- // TextEmitPass for details.
- void TextNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- LimitResult limit_result = LimitVersions(compiler, trace);
- if (limit_result == DONE) return;
- DCHECK(limit_result == CONTINUE);
- if (trace->cp_offset() + Length() > RegExpMacroAssembler::kMaxCPOffset) {
- compiler->SetRegExpTooBig();
- return;
- }
- if (compiler->ascii()) {
- int dummy = 0;
- TextEmitPass(compiler, NON_ASCII_MATCH, false, trace, false, &dummy);
- }
- bool first_elt_done = false;
- int bound_checked_to = trace->cp_offset() - 1;
- bound_checked_to += trace->bound_checked_up_to();
- // If a character is preloaded into the current character register then
- // check that now.
- if (trace->characters_preloaded() == 1) {
- for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
- if (!SkipPass(pass, compiler->ignore_case())) {
- TextEmitPass(compiler,
- static_cast<TextEmitPassType>(pass),
- true,
- trace,
- false,
- &bound_checked_to);
- }
- }
- first_elt_done = true;
- }
- for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
- if (!SkipPass(pass, compiler->ignore_case())) {
- TextEmitPass(compiler,
- static_cast<TextEmitPassType>(pass),
- false,
- trace,
- first_elt_done,
- &bound_checked_to);
- }
- }
- Trace successor_trace(*trace);
- successor_trace.set_at_start(false);
- successor_trace.AdvanceCurrentPositionInTrace(Length(), compiler);
- RecursionCheck rc(compiler);
- on_success()->Emit(compiler, &successor_trace);
- }
- void Trace::InvalidateCurrentCharacter() {
- characters_preloaded_ = 0;
- }
- void Trace::AdvanceCurrentPositionInTrace(int by, RegExpCompiler* compiler) {
- DCHECK(by > 0);
- // We don't have an instruction for shifting the current character register
- // down or for using a shifted value for anything so lets just forget that
- // we preloaded any characters into it.
- characters_preloaded_ = 0;
- // Adjust the offsets of the quick check performed information. This
- // information is used to find out what we already determined about the
- // characters by means of mask and compare.
- quick_check_performed_.Advance(by, compiler->ascii());
- cp_offset_ += by;
- if (cp_offset_ > RegExpMacroAssembler::kMaxCPOffset) {
- compiler->SetRegExpTooBig();
- cp_offset_ = 0;
- }
- bound_checked_up_to_ = Max(0, bound_checked_up_to_ - by);
- }
- void TextNode::MakeCaseIndependent(bool is_ascii) {
- int element_count = elms_->length();
- for (int i = 0; i < element_count; i++) {
- TextElement elm = elms_->at(i);
- if (elm.text_type() == TextElement::CHAR_CLASS) {
- RegExpCharacterClass* cc = elm.char_class();
- // None of the standard character classes is different in the case
- // independent case and it slows us down if we don't know that.
- if (cc->is_standard(zone())) continue;
- ZoneList<CharacterRange>* ranges = cc->ranges(zone());
- int range_count = ranges->length();
- for (int j = 0; j < range_count; j++) {
- ranges->at(j).AddCaseEquivalents(ranges, is_ascii, zone());
- }
- }
- }
- }
- int TextNode::GreedyLoopTextLength() {
- TextElement elm = elms_->at(elms_->length() - 1);
- return elm.cp_offset() + elm.length();
- }
- RegExpNode* TextNode::GetSuccessorOfOmnivorousTextNode(
- RegExpCompiler* compiler) {
- if (elms_->length() != 1) return NULL;
- TextElement elm = elms_->at(0);
- if (elm.text_type() != TextElement::CHAR_CLASS) return NULL;
- RegExpCharacterClass* node = elm.char_class();
- ZoneList<CharacterRange>* ranges = node->ranges(zone());
- if (!CharacterRange::IsCanonical(ranges)) {
- CharacterRange::Canonicalize(ranges);
- }
- if (node->is_negated()) {
- return ranges->length() == 0 ? on_success() : NULL;
- }
- if (ranges->length() != 1) return NULL;
- uint32_t max_char;
- if (compiler->ascii()) {
- max_char = String::kMaxOneByteCharCode;
- } else {
- max_char = String::kMaxUtf16CodeUnit;
- }
- return ranges->at(0).IsEverything(max_char) ? on_success() : NULL;
- }
- // Finds the fixed match length of a sequence of nodes that goes from
- // this alternative and back to this choice node. If there are variable
- // length nodes or other complications in the way then return a sentinel
- // value indicating that a greedy loop cannot be constructed.
- int ChoiceNode::GreedyLoopTextLengthForAlternative(
- GuardedAlternative* alternative) {
- int length = 0;
- RegExpNode* node = alternative->node();
- // Later we will generate code for all these text nodes using recursion
- // so we have to limit the max number.
- int recursion_depth = 0;
- while (node != this) {
- if (recursion_depth++ > RegExpCompiler::kMaxRecursion) {
- return kNodeIsTooComplexForGreedyLoops;
- }
- int node_length = node->GreedyLoopTextLength();
- if (node_length == kNodeIsTooComplexForGreedyLoops) {
- return kNodeIsTooComplexForGreedyLoops;
- }
- length += node_length;
- SeqRegExpNode* seq_node = static_cast<SeqRegExpNode*>(node);
- node = seq_node->on_success();
- }
- return length;
- }
- void LoopChoiceNode::AddLoopAlternative(GuardedAlternative alt) {
- DCHECK_EQ(loop_node_, NULL);
- AddAlternative(alt);
- loop_node_ = alt.node();
- }
- void LoopChoiceNode::AddContinueAlternative(GuardedAlternative alt) {
- DCHECK_EQ(continue_node_, NULL);
- AddAlternative(alt);
- continue_node_ = alt.node();
- }
- void LoopChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- if (trace->stop_node() == this) {
- int text_length =
- GreedyLoopTextLengthForAlternative(&(alternatives_->at(0)));
- DCHECK(text_length != kNodeIsTooComplexForGreedyLoops);
- // Update the counter-based backtracking info on the stack. This is an
- // optimization for greedy loops (see below).
- DCHECK(trace->cp_offset() == text_length);
- macro_assembler->AdvanceCurrentPosition(text_length);
- macro_assembler->GoTo(trace->loop_label());
- return;
- }
- DCHECK(trace->stop_node() == NULL);
- if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- return;
- }
- ChoiceNode::Emit(compiler, trace);
- }
- int ChoiceNode::CalculatePreloadCharacters(RegExpCompiler* compiler,
- int eats_at_least) {
- int preload_characters = Min(4, eats_at_least);
- if (compiler->macro_assembler()->CanReadUnaligned()) {
- bool ascii = compiler->ascii();
- if (ascii) {
- if (preload_characters > 4) preload_characters = 4;
- // We can't preload 3 characters because there is no machine instruction
- // to do that. We can't just load 4 because we could be reading
- // beyond the end of the string, which could cause a memory fault.
- if (preload_characters == 3) preload_characters = 2;
- } else {
- if (preload_characters > 2) preload_characters = 2;
- }
- } else {
- if (preload_characters > 1) preload_characters = 1;
- }
- return preload_characters;
- }
- // This class is used when generating the alternatives in a choice node. It
- // records the way the alternative is being code generated.
- class AlternativeGeneration: public Malloced {
- public:
- AlternativeGeneration()
- : possible_success(),
- expects_preload(false),
- after(),
- quick_check_details() { }
- Label possible_success;
- bool expects_preload;
- Label after;
- QuickCheckDetails quick_check_details;
- };
- // Creates a list of AlternativeGenerations. If the list has a reasonable
- // size then it is on the stack, otherwise the excess is on the heap.
- class AlternativeGenerationList {
- public:
- AlternativeGenerationList(int count, Zone* zone)
- : alt_gens_(count, zone) {
- for (int i = 0; i < count && i < kAFew; i++) {
- alt_gens_.Add(a_few_alt_gens_ + i, zone);
- }
- for (int i = kAFew; i < count; i++) {
- alt_gens_.Add(new AlternativeGeneration(), zone);
- }
- }
- ~AlternativeGenerationList() {
- for (int i = kAFew; i < alt_gens_.length(); i++) {
- delete alt_gens_[i];
- alt_gens_[i] = NULL;
- }
- }
- AlternativeGeneration* at(int i) {
- return alt_gens_[i];
- }
- private:
- static const int kAFew = 10;
- ZoneList<AlternativeGeneration*> alt_gens_;
- AlternativeGeneration a_few_alt_gens_[kAFew];
- };
- // The '2' variant is has inclusive from and exclusive to.
- // This covers \s as defined in ECMA-262 5.1, 15.10.2.12,
- // which include WhiteSpace (7.2) or LineTerminator (7.3) values.
- static const int kSpaceRanges[] = { '\t', '\r' + 1, ' ', ' ' + 1,
- 0x00A0, 0x00A1, 0x1680, 0x1681, 0x180E, 0x180F, 0x2000, 0x200B,
- 0x2028, 0x202A, 0x202F, 0x2030, 0x205F, 0x2060, 0x3000, 0x3001,
- 0xFEFF, 0xFF00, 0x10000 };
- static const int kSpaceRangeCount = ARRAY_SIZE(kSpaceRanges);
- static const int kWordRanges[] = {
- '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, 0x10000 };
- static const int kWordRangeCount = ARRAY_SIZE(kWordRanges);
- static const int kDigitRanges[] = { '0', '9' + 1, 0x10000 };
- static const int kDigitRangeCount = ARRAY_SIZE(kDigitRanges);
- static const int kSurrogateRanges[] = { 0xd800, 0xe000, 0x10000 };
- static const int kSurrogateRangeCount = ARRAY_SIZE(kSurrogateRanges);
- static const int kLineTerminatorRanges[] = { 0x000A, 0x000B, 0x000D, 0x000E,
- 0x2028, 0x202A, 0x10000 };
- static const int kLineTerminatorRangeCount = ARRAY_SIZE(kLineTerminatorRanges);
- void BoyerMoorePositionInfo::Set(int character) {
- SetInterval(Interval(character, character));
- }
- void BoyerMoorePositionInfo::SetInterval(const Interval& interval) {
- s_ = AddRange(s_, kSpaceRanges, kSpaceRangeCount, interval);
- w_ = AddRange(w_, kWordRanges, kWordRangeCount, interval);
- d_ = AddRange(d_, kDigitRanges, kDigitRangeCount, interval);
- surrogate_ =
- AddRange(surrogate_, kSurrogateRanges, kSurrogateRangeCount, interval);
- if (interval.to() - interval.from() >= kMapSize - 1) {
- if (map_count_ != kMapSize) {
- map_count_ = kMapSize;
- for (int i = 0; i < kMapSize; i++) map_->at(i) = true;
- }
- return;
- }
- for (int i = interval.from(); i <= interval.to(); i++) {
- int mod_character = (i & kMask);
- if (!map_->at(mod_character)) {
- map_count_++;
- map_->at(mod_character) = true;
- }
- if (map_count_ == kMapSize) return;
- }
- }
- void BoyerMoorePositionInfo::SetAll() {
- s_ = w_ = d_ = kLatticeUnknown;
- if (map_count_ != kMapSize) {
- map_count_ = kMapSize;
- for (int i = 0; i < kMapSize; i++) map_->at(i) = true;
- }
- }
- BoyerMooreLookahead::BoyerMooreLookahead(
- int length, RegExpCompiler* compiler, Zone* zone)
- : length_(length),
- compiler_(compiler) {
- if (compiler->ascii()) {
- max_char_ = String::kMaxOneByteCharCode;
- } else {
- max_char_ = String::kMaxUtf16CodeUnit;
- }
- bitmaps_ = new(zone) ZoneList<BoyerMoorePositionInfo*>(length, zone);
- for (int i = 0; i < length; i++) {
- bitmaps_->Add(new(zone) BoyerMoorePositionInfo(zone), zone);
- }
- }
- // Find the longest range of lookahead that has the fewest number of different
- // characters that can occur at a given position. Since we are optimizing two
- // different parameters at once this is a tradeoff.
- bool BoyerMooreLookahead::FindWorthwhileInterval(int* from, int* to) {
- int biggest_points = 0;
- // If more than 32 characters out of 128 can occur it is unlikely that we can
- // be lucky enough to step forwards much of the time.
- const int kMaxMax = 32;
- for (int max_number_of_chars = 4;
- max_number_of_chars < kMaxMax;
- max_number_of_chars *= 2) {
- biggest_points =
- FindBestInterval(max_number_of_chars, biggest_points, from, to);
- }
- if (biggest_points == 0) return false;
- return true;
- }
- // Find the highest-points range between 0 and length_ where the character
- // information is not too vague. 'Too vague' means that there are more than
- // max_number_of_chars that can occur at this position. Calculates the number
- // of points as the product of width-of-the-range and
- // probability-of-finding-one-of-the-characters, where the probability is
- // calculated using the frequency distribution of the sample subject string.
- int BoyerMooreLookahead::FindBestInterval(
- int max_number_of_chars, int old_biggest_points, int* from, int* to) {
- int biggest_points = old_biggest_points;
- static const int kSize = RegExpMacroAssembler::kTableSize;
- for (int i = 0; i < length_; ) {
- while (i < length_ && Count(i) > max_number_of_chars) i++;
- if (i == length_) break;
- int remembered_from = i;
- bool union_map[kSize];
- for (int j = 0; j < kSize; j++) union_map[j] = false;
- while (i < length_ && Count(i) <= max_number_of_chars) {
- BoyerMoorePositionInfo* map = bitmaps_->at(i);
- for (int j = 0; j < kSize; j++) union_map[j] |= map->at(j);
- i++;
- }
- int frequency = 0;
- for (int j = 0; j < kSize; j++) {
- if (union_map[j]) {
- // Add 1 to the frequency to give a small per-character boost for
- // the cases where our sampling is not good enough and many
- // characters have a frequency of zero. This means the frequency
- // can theoretically be up to 2*kSize though we treat it mostly as
- // a fraction of kSize.
- frequency += compiler_->frequency_collator()->Frequency(j) + 1;
- }
- }
- // We use the probability of skipping times the distance we are skipping to
- // judge the effectiveness of this. Actually we have a cut-off: By
- // dividing by 2 we switch off the skipping if the probability of skipping
- // is less than 50%. This is because the multibyte mask-and-compare
- // skipping in quickcheck is more likely to do well on this case.
- bool in_quickcheck_range = ((i - remembered_from < 4) ||
- (compiler_->ascii() ? remembered_from <= 4 : remembered_from <= 2));
- // Called 'probability' but it is only a rough estimate and can actually
- // be outside the 0-kSize range.
- int probability = (in_quickcheck_range ? kSize / 2 : kSize) - frequency;
- int points = (i - remembered_from) * probability;
- if (points > biggest_points) {
- *from = remembered_from;
- *to = i - 1;
- biggest_points = points;
- }
- }
- return biggest_points;
- }
- // Take all the characters that will not prevent a successful match if they
- // occur in the subject string in the range between min_lookahead and
- // max_lookahead (inclusive) measured from the current position. If the
- // character at max_lookahead offset is not one of these characters, then we
- // can safely skip forwards by the number of characters in the range.
- int BoyerMooreLookahead::GetSkipTable(int min_lookahead,
- int max_lookahead,
- Handle<ByteArray> boolean_skip_table) {
- const int kSize = RegExpMacroAssembler::kTableSize;
- const int kSkipArrayEntry = 0;
- const int kDontSkipArrayEntry = 1;
- for (int i = 0; i < kSize; i++) {
- boolean_skip_table->set(i, kSkipArrayEntry);
- }
- int skip = max_lookahead + 1 - min_lookahead;
- for (int i = max_lookahead; i >= min_lookahead; i--) {
- BoyerMoorePositionInfo* map = bitmaps_->at(i);
- for (int j = 0; j < kSize; j++) {
- if (map->at(j)) {
- boolean_skip_table->set(j, kDontSkipArrayEntry);
- }
- }
- }
- return skip;
- }
- // See comment above on the implementation of GetSkipTable.
- bool BoyerMooreLookahead::EmitSkipInstructions(RegExpMacroAssembler* masm) {
- const int kSize = RegExpMacroAssembler::kTableSize;
- int min_lookahead = 0;
- int max_lookahead = 0;
- if (!FindWorthwhileInterval(&min_lookahead, &max_lookahead)) return false;
- bool found_single_character = false;
- int single_character = 0;
- for (int i = max_lookahead; i >= min_lookahead; i--) {
- BoyerMoorePositionInfo* map = bitmaps_->at(i);
- if (map->map_count() > 1 ||
- (found_single_character && map->map_count() != 0)) {
- found_single_character = false;
- break;
- }
- for (int j = 0; j < kSize; j++) {
- if (map->at(j)) {
- found_single_character = true;
- single_character = j;
- break;
- }
- }
- }
- int lookahead_width = max_lookahead + 1 - min_lookahead;
- if (found_single_character && lookahead_width == 1 && max_lookahead < 3) {
- // The mask-compare can probably handle this better.
- return false;
- }
- if (found_single_character) {
- Label cont, again;
- masm->Bind(&again);
- masm->LoadCurrentCharacter(max_lookahead, &cont, true);
- if (max_char_ > kSize) {
- masm->CheckCharacterAfterAnd(single_character,
- RegExpMacroAssembler::kTableMask,
- &cont);
- } else {
- masm->CheckCharacter(single_character, &cont);
- }
- masm->AdvanceCurrentPosition(lookahead_width);
- masm->GoTo(&again);
- masm->Bind(&cont);
- return true;
- }
- Factory* factory = masm->zone()->isolate()->factory();
- Handle<ByteArray> boolean_skip_table = factory->NewByteArray(kSize, TENURED);
- int skip_distance = GetSkipTable(
- min_lookahead, max_lookahead, boolean_skip_table);
- DCHECK(skip_distance != 0);
- Label cont, again;
- masm->Bind(&again);
- masm->LoadCurrentCharacter(max_lookahead, &cont, true);
- masm->CheckBitInTable(boolean_skip_table, &cont);
- masm->AdvanceCurrentPosition(skip_distance);
- masm->GoTo(&again);
- masm->Bind(&cont);
- return true;
- }
- /* Code generation for choice nodes.
- *
- * We generate quick checks that do a mask and compare to eliminate a
- * choice. If the quick check succeeds then it jumps to the continuation to
- * do slow checks and check subsequent nodes. If it fails (the common case)
- * it falls through to the next choice.
- *
- * Here is the desired flow graph. Nodes directly below each other imply
- * fallthrough. Alternatives 1 and 2 have quick checks. Alternative
- * 3 doesn't have a quick check so we have to call the slow check.
- * Nodes are marked Qn for quick checks and Sn for slow checks. The entire
- * regexp continuation is generated directly after the Sn node, up to the
- * next GoTo if we decide to reuse some already generated code. Some
- * nodes expect preload_characters to be preloaded into the current
- * character register. R nodes do this preloading. Vertices are marked
- * F for failures and S for success (possible success in the case of quick
- * nodes). L, V, < and > are used as arrow heads.
- *
- * ----------> R
- * |
- * V
- * Q1 -----> S1
- * | S /
- * F| /
- * | F/
- * | /
- * | R
- * | /
- * V L
- * Q2 -----> S2
- * | S /
- * F| /
- * | F/
- * | /
- * | R
- * | /
- * V L
- * S3
- * |
- * F|
- * |
- * R
- * |
- * backtrack V
- * <----------Q4
- * \ F |
- * \ |S
- * \ F V
- * \-----S4
- *
- * For greedy loops we reverse our expectation and expect to match rather
- * than fail. Therefore we want the loop code to look like this (U is the
- * unwind code that steps back in the greedy loop). The following alternatives
- * look the same as above.
- * _____
- * / \
- * V |
- * ----------> S1 |
- * /| |
- * / |S |
- * F/ \_____/
- * /
- * |<-----------
- * | \
- * V \
- * Q2 ---> S2 \
- * | S / |
- * F| / |
- * | F/ |
- * | / |
- * | R |
- * | / |
- * F VL |
- * <------U |
- * back |S |
- * \______________/
- */
- void ChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- int choice_count = alternatives_->length();
- #ifdef DEBUG
- for (int i = 0; i < choice_count - 1; i++) {
- GuardedAlternative alternative = alternatives_->at(i);
- ZoneList<Guard*>* guards = alternative.guards();
- int guard_count = (guards == NULL) ? 0 : guards->length();
- for (int j = 0; j < guard_count; j++) {
- DCHECK(!trace->mentions_reg(guards->at(j)->reg()));
- }
- }
- #endif
- LimitResult limit_result = LimitVersions(compiler, trace);
- if (limit_result == DONE) return;
- DCHECK(limit_result == CONTINUE);
- int new_flush_budget = trace->flush_budget() / choice_count;
- if (trace->flush_budget() == 0 && trace->actions() != NULL) {
- trace->Flush(compiler, this);
- return;
- }
- RecursionCheck rc(compiler);
- Trace* current_trace = trace;
- int text_length = GreedyLoopTextLengthForAlternative(&(alternatives_->at(0)));
- bool greedy_loop = false;
- Label greedy_loop_label;
- Trace counter_backtrack_trace;
- counter_backtrack_trace.set_backtrack(&greedy_loop_label);
- if (not_at_start()) counter_backtrack_trace.set_at_start(false);
- if (choice_count > 1 && text_length != kNodeIsTooComplexForGreedyLoops) {
- // Here we have special handling for greedy loops containing only text nodes
- // and other simple nodes. These are handled by pushing the current
- // position on the stack and then incrementing the current position each
- // time around the switch. On backtrack we decrement the current position
- // and check it against the pushed value. This avoids pushing backtrack
- // information for each iteration of the loop, which could take up a lot of
- // space.
- greedy_loop = true;
- DCHECK(trace->stop_node() == NULL);
- macro_assembler->PushCurrentPosition();
- current_trace = &counter_backtrack_trace;
- Label greedy_match_failed;
- Trace greedy_match_trace;
- if (not_at_start()) greedy_match_trace.set_at_start(false);
- greedy_match_trace.set_backtrack(&greedy_match_failed);
- Label loop_label;
- macro_assembler->Bind(&loop_label);
- greedy_match_trace.set_stop_node(this);
- greedy_match_trace.set_loop_label(&loop_label);
- alternatives_->at(0).node()->Emit(compiler, &greedy_match_trace);
- macro_assembler->Bind(&greedy_match_failed);
- }
- Label second_choice; // For use in greedy matches.
- macro_assembler->Bind(&second_choice);
- int first_normal_choice = greedy_loop ? 1 : 0;
- bool not_at_start = current_trace->at_start() == Trace::FALSE_VALUE;
- const int kEatsAtLeastNotYetInitialized = -1;
- int eats_at_least = kEatsAtLeastNotYetInitialized;
- bool skip_was_emitted = false;
- if (!greedy_loop && choice_count == 2) {
- GuardedAlternative alt1 = alternatives_->at(1);
- if (alt1.guards() == NULL || alt1.guards()->length() == 0) {
- RegExpNode* eats_anything_node = alt1.node();
- if (eats_anything_node->GetSuccessorOfOmnivorousTextNode(compiler) ==
- this) {
- // At this point we know that we are at a non-greedy loop that will eat
- // any character one at a time. Any non-anchored regexp has such a
- // loop prepended to it in order to find where it starts. We look for
- // a pattern of the form ...abc... where we can look 6 characters ahead
- // and step forwards 3 if the character is not one of abc. Abc need
- // not be atoms, they can be any reasonably limited character class or
- // small alternation.
- DCHECK(trace->is_trivial()); // This is the case on LoopChoiceNodes.
- BoyerMooreLookahead* lookahead = bm_info(not_at_start);
- if (lookahead == NULL) {
- eats_at_least = Min(kMaxLookaheadForBoyerMoore,
- EatsAtLeast(kMaxLookaheadForBoyerMoore,
- kRecursionBudget,
- not_at_start));
- if (eats_at_least >= 1) {
- BoyerMooreLookahead* bm =
- new(zone()) BoyerMooreLookahead(eats_at_least,
- compiler,
- zone());
- GuardedAlternative alt0 = alternatives_->at(0);
- alt0.node()->FillInBMInfo(0, kRecursionBudget, bm, not_at_start);
- skip_was_emitted = bm->EmitSkipInstructions(macro_assembler);
- }
- } else {
- skip_was_emitted = lookahead->EmitSkipInstructions(macro_assembler);
- }
- }
- }
- }
- if (eats_at_least == kEatsAtLeastNotYetInitialized) {
- // Save some time by looking at most one machine word ahead.
- eats_at_least =
- EatsAtLeast(compiler->ascii() ? 4 : 2, kRecursionBudget, not_at_start);
- }
- int preload_characters = CalculatePreloadCharacters(compiler, eats_at_least);
- bool preload_is_current = !skip_was_emitted &&
- (current_trace->characters_preloaded() == preload_characters);
- bool preload_has_checked_bounds = preload_is_current;
- AlternativeGenerationList alt_gens(choice_count, zone());
- // For now we just call all choices one after the other. The idea ultimately
- // is to use the Dispatch table to try only the relevant ones.
- for (int i = first_normal_choice; i < choice_count; i++) {
- GuardedAlternative alternative = alternatives_->at(i);
- AlternativeGeneration* alt_gen = alt_gens.at(i);
- alt_gen->quick_check_details.set_characters(preload_characters);
- ZoneList<Guard*>* guards = alternative.guards();
- int guard_count = (guards == NULL) ? 0 : guards->length();
- Trace new_trace(*current_trace);
- new_trace.set_characters_preloaded(preload_is_current ?
- preload_characters :
- 0);
- if (preload_has_checked_bounds) {
- new_trace.set_bound_checked_up_to(preload_characters);
- }
- new_trace.quick_check_performed()->Clear();
- if (not_at_start_) new_trace.set_at_start(Trace::FALSE_VALUE);
- alt_gen->expects_preload = preload_is_current;
- bool generate_full_check_inline = false;
- if (FLAG_regexp_optimization &&
- try_to_emit_quick_check_for_alternative(i) &&
- alternative.node()->EmitQuickCheck(compiler,
- &new_trace,
- preload_has_checked_bounds,
- &alt_gen->possible_success,
- &alt_gen->quick_check_details,
- i < choice_count - 1)) {
- // Quick check was generated for this choice.
- preload_is_current = true;
- preload_has_checked_bounds = true;
- // On the last choice in the ChoiceNode we generated the quick
- // check to fall through on possible success. So now we need to
- // generate the full check inline.
- if (i == choice_count - 1) {
- macro_assembler->Bind(&alt_gen->possible_success);
- new_trace.set_quick_check_performed(&alt_gen->quick_check_details);
- new_trace.set_characters_preloaded(preload_characters);
- new_trace.set_bound_checked_up_to(preload_characters);
- generate_full_check_inline = true;
- }
- } else if (alt_gen->quick_check_details.cannot_match()) {
- if (i == choice_count - 1 && !greedy_loop) {
- macro_assembler->GoTo(trace->backtrack());
- }
- continue;
- } else {
- // No quick check was generated. Put the full code here.
- // If this is not the first choice then there could be slow checks from
- // previous cases that go here when they fail. There's no reason to
- // insist that they preload characters since the slow check we are about
- // to generate probably can't use it.
- if (i != first_normal_choice) {
- alt_gen->expects_preload = false;
- new_trace.InvalidateCurrentCharacter();
- }
- if (i < choice_count - 1) {
- new_trace.set_backtrack(&alt_gen->after);
- }
- generate_full_check_inline = true;
- }
- if (generate_full_check_inline) {
- if (new_trace.actions() != NULL) {
- new_trace.set_flush_budget(new_flush_budget);
- }
- for (int j = 0; j < guard_count; j++) {
- GenerateGuard(macro_assembler, guards->at(j), &new_trace);
- }
- alternative.node()->Emit(compiler, &new_trace);
- preload_is_current = false;
- }
- macro_assembler->Bind(&alt_gen->after);
- }
- if (greedy_loop) {
- macro_assembler->Bind(&greedy_loop_label);
- // If we have unwound to the bottom then backtrack.
- macro_assembler->CheckGreedyLoop(trace->backtrack());
- // Otherwise try the second priority at an earlier position.
- macro_assembler->AdvanceCurrentPosition(-text_length);
- macro_assembler->GoTo(&second_choice);
- }
- // At this point we need to generate slow checks for the alternatives where
- // the quick check was inlined. We can recognize these because the associated
- // label was bound.
- for (int i = first_normal_choice; i < choice_count - 1; i++) {
- AlternativeGeneration* alt_gen = alt_gens.at(i);
- Trace new_trace(*current_trace);
- // If there are actions to be flushed we have to limit how many times
- // they are flushed. Take the budget of the parent trace and distribute
- // it fairly amongst the children.
- if (new_trace.actions() != NULL) {
- new_trace.set_flush_budget(new_flush_budget);
- }
- EmitOutOfLineContinuation(compiler,
- &new_trace,
- alternatives_->at(i),
- alt_gen,
- preload_characters,
- alt_gens.at(i + 1)->expects_preload);
- }
- }
- void ChoiceNode::EmitOutOfLineContinuation(RegExpCompiler* compiler,
- Trace* trace,
- GuardedAlternative alternative,
- AlternativeGeneration* alt_gen,
- int preload_characters,
- bool next_expects_preload) {
- if (!alt_gen->possible_success.is_linked()) return;
- RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
- macro_assembler->Bind(&alt_gen->possible_success);
- Trace out_of_line_trace(*trace);
- out_of_line_trace.set_characters_preloaded(preload_characters);
- out_of_line_trace.set_quick_check_performed(&alt_gen->quick_check_details);
- if (not_at_start_) out_of_line_trace.set_at_start(Trace::FALSE_VALUE);
- ZoneList<Guard*>* guards = alternative.guards();
- int guard_count = (guards == NULL) ? 0 : guards->length();
- if (next_expects_preload) {
- Label reload_current_char;
- out_of_line_trace.set_backtrack(&reload_current_char);
- for (int j = 0; j < guard_count; j++) {
- GenerateGuard(macro_assembler, guards->at(j), &out_of_line_trace);
- }
- alternative.node()->Emit(compiler, &out_of_line_trace);
- macro_assembler->Bind(&reload_current_char);
- // Reload the current character, since the next quick check expects that.
- // We don't need to check bounds here because we only get into this
- // code through a quick check which already did the checked load.
- macro_assembler->LoadCurrentCharacter(trace->cp_offset(),
- NULL,
- false,
- preload_characters);
- macro_assembler->GoTo(&(alt_gen->after));
- } else {
- out_of_line_trace.set_backtrack(&(alt_gen->after));
- for (int j = 0; j < guard_count; j++) {
- GenerateGuard(macro_assembler, guards->at(j), &out_of_line_trace);
- }
- alternative.node()->Emit(compiler, &out_of_line_trace);
- }
- }
- void ActionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- LimitResult limit_result = LimitVersions(compiler, trace);
- if (limit_result == DONE) return;
- DCHECK(limit_result == CONTINUE);
- RecursionCheck rc(compiler);
- switch (action_type_) {
- case STORE_POSITION: {
- Trace::DeferredCapture
- new_capture(data_.u_position_register.reg,
- data_.u_position_register.is_capture,
- trace);
- Trace new_trace = *trace;
- new_trace.add_action(&new_capture);
- on_success()->Emit(compiler, &new_trace);
- break;
- }
- case INCREMENT_REGISTER: {
- Trace::DeferredIncrementRegister
- new_increment(data_.u_increment_register.reg);
- Trace new_trace = *trace;
- new_trace.add_action(&new_increment);
- on_success()->Emit(compiler, &new_trace);
- break;
- }
- case SET_REGISTER: {
- Trace::DeferredSetRegister
- new_set(data_.u_store_register.reg, data_.u_store_register.value);
- Trace new_trace = *trace;
- new_trace.add_action(&new_set);
- on_success()->Emit(compiler, &new_trace);
- break;
- }
- case CLEAR_CAPTURES: {
- Trace::DeferredClearCaptures
- new_capture(Interval(data_.u_clear_captures.range_from,
- data_.u_clear_captures.range_to));
- Trace new_trace = *trace;
- new_trace.add_action(&new_capture);
- on_success()->Emit(compiler, &new_trace);
- break;
- }
- case BEGIN_SUBMATCH:
- if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- } else {
- assembler->WriteCurrentPositionToRegister(
- data_.u_submatch.current_position_register, 0);
- assembler->WriteStackPointerToRegister(
- data_.u_submatch.stack_pointer_register);
- on_success()->Emit(compiler, trace);
- }
- break;
- case EMPTY_MATCH_CHECK: {
- int start_pos_reg = data_.u_empty_match_check.start_register;
- int stored_pos = 0;
- int rep_reg = data_.u_empty_match_check.repetition_register;
- bool has_minimum = (rep_reg != RegExpCompiler::kNoRegister);
- bool know_dist = trace->GetStoredPosition(start_pos_reg, &stored_pos);
- if (know_dist && !has_minimum && stored_pos == trace->cp_offset()) {
- // If we know we haven't advanced and there is no minimum we
- // can just backtrack immediately.
- assembler->GoTo(trace->backtrack());
- } else if (know_dist && stored_pos < trace->cp_offset()) {
- // If we know we've advanced we can generate the continuation
- // immediately.
- on_success()->Emit(compiler, trace);
- } else if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- } else {
- Label skip_empty_check;
- // If we have a minimum number of repetitions we check the current
- // number first and skip the empty check if it's not enough.
- if (has_minimum) {
- int limit = data_.u_empty_match_check.repetition_limit;
- assembler->IfRegisterLT(rep_reg, limit, &skip_empty_check);
- }
- // If the match is empty we bail out, otherwise we fall through
- // to the on-success continuation.
- assembler->IfRegisterEqPos(data_.u_empty_match_check.start_register,
- trace->backtrack());
- assembler->Bind(&skip_empty_check);
- on_success()->Emit(compiler, trace);
- }
- break;
- }
- case POSITIVE_SUBMATCH_SUCCESS: {
- if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- return;
- }
- assembler->ReadCurrentPositionFromRegister(
- data_.u_submatch.current_position_register);
- assembler->ReadStackPointerFromRegister(
- data_.u_submatch.stack_pointer_register);
- int clear_register_count = data_.u_submatch.clear_register_count;
- if (clear_register_count == 0) {
- on_success()->Emit(compiler, trace);
- return;
- }
- int clear_registers_from = data_.u_submatch.clear_register_from;
- Label clear_registers_backtrack;
- Trace new_trace = *trace;
- new_trace.set_backtrack(&clear_registers_backtrack);
- on_success()->Emit(compiler, &new_trace);
- assembler->Bind(&clear_registers_backtrack);
- int clear_registers_to = clear_registers_from + clear_register_count - 1;
- assembler->ClearRegisters(clear_registers_from, clear_registers_to);
- DCHECK(trace->backtrack() == NULL);
- assembler->Backtrack();
- return;
- }
- default:
- UNREACHABLE();
- }
- }
- void BackReferenceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
- RegExpMacroAssembler* assembler = compiler->macro_assembler();
- if (!trace->is_trivial()) {
- trace->Flush(compiler, this);
- return;
- }
- LimitResult limit_result = LimitVersions(compiler, trace);
- if (limit_result == DONE) return;
- DCHECK(limit_result == CONTINUE);
- RecursionCheck rc(compiler);
- DCHECK_EQ(start_reg_ + 1, end_reg_);
- if (compiler->ignore_case()) {
- assembler->CheckNotBackReferenceIgnoreCase(start_reg_,
- trace->backtrack());
- } else {
- assembler->CheckNotBackReference(start_reg_, trace->backtrack());
- }
- on_success()->Emit(compiler, trace);
- }
- // -------------------------------------------------------------------
- // Dot/dotty output
- #ifdef DEBUG
- class DotPrinter: public NodeVisitor {
- public:
- DotPrinter(OStream& os, bool ignore_case) // NOLINT
- : os_(os),
- ignore_case_(ignore_case) {}
- void PrintNode(const char* label, RegExpNode* node);
- void Visit(RegExpNode* node);
- void PrintAttributes(RegExpNode* from);
- void PrintOnFailure(RegExpNode* from, RegExpNode* to);
- #define DECLARE_VISIT(Type) \
- virtual void Visit##Type(Type##Node* that);
- FOR_EACH_NODE_TYPE(DECLARE_VISIT)
- #undef DECLARE_VISIT
- private:
- OStream& os_;
- bool ignore_case_;
- };
- void DotPrinter::PrintNode(const char* label, RegExpNode* node) {
- os_ << "digraph G {\n graph [label=\"";
- for (int i = 0; label[i]; i++) {
- switch (label[i]) {
- case '\\':
- os_ << "\\\\";
- break;
- case '"':
- os_ << "\"";
- break;
- default:
- os_ << label[i];
- break;
- }
- }
- os_ << "\"];\n";
- Visit(node);
- os_ << "}" << endl;
- }
- void DotPrinter::Visit(RegExpNode* node) {
- if (node->info()->visited) return;
- node->info()->visited = true;
- node->Accept(this);
- }
- void DotPrinter::PrintOnFailure(RegExpNode* from, RegExpNode* on_failure) {
- os_ << " n" << from << " -> n" << on_failure << " [style=dotted];\n";
- Visit(on_failure);
- }
- class TableEntryBodyPrinter {
- public:
- TableEntryBodyPrinter(OStream& os, ChoiceNode* choice) // NOLINT
- : os_(os),
- choice_(choice) {}
- void Call(uc16 from, DispatchTable::Entry entry) {
- OutSet* out_set = entry.out_set();
- for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
- if (out_set->Get(i)) {
- os_ << " n" << choice() << ":s" << from << "o" << i << " -> n"
- << choice()->alternatives()->at(i).node() << ";\n";
- }
- }
- }
- private:
- ChoiceNode* choice() { return choice_; }
- OStream& os_;
- ChoiceNode* choice_;
- };
- class TableEntryHeaderPrinter {
- public:
- explicit TableEntryHeaderPrinter(OStream& os) // NOLINT
- : first_(true),
- os_(os) {}
- void Call(uc16 from, DispatchTable::Entry entry) {
- if (first_) {
- first_ = false;
- } else {
- os_ << "|";
- }
- os_ << "{\\" << AsUC16(from) << "-\\" << AsUC16(entry.to()) << "|{";
- OutSet* out_set = entry.out_set();
- int priority = 0;
- for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
- if (out_set->Get(i)) {
- if (priority > 0) os_ << "|";
- os_ << "<s" << from << "o" << i << "> " << priority;
- priority++;
- }
- }
- os_ << "}}";
- }
- private:
- bool first_;
- OStream& os_;
- };
- class AttributePrinter {
- public:
- explicit AttributePrinter(OStream& os) // NOLINT
- : os_(os),
- first_(true) {}
- void PrintSeparator() {
- if (first_) {
- first_ = false;
- } else {
- os_ << "|";
- }
- }
- void PrintBit(const char* name, bool value) {
- if (!value) return;
- PrintSeparator();
- os_ << "{" << name << "}";
- }
- void PrintPositive(const char* name, int value) {
- if (value < 0) return;
- PrintSeparator();
- os_ << "{" << name << "|" << value << "}";
- }
- private:
- OStream& os_;
- bool first_;
- };
- void DotPrinter::PrintAttributes(RegExpNode* that) {
- os_ << " a" << that << " [shape=Mrecord, color=grey, fontcolor=grey, "
- << "margin=0.1, fontsize=10, label=\"{";
- AttributePrinter printer(os_);
- NodeInfo* info = that->info();
- printer.PrintBit("NI", info->follows_newline_interest);
- printer.PrintBit("WI", info->follows_word_interest);
- printer.PrintBit("SI", info->follows_start_interest);
- Label* label = that->label();
- if (label->is_bound())
- printer.PrintPositive("@", label->pos());
- os_ << "}\"];\n"
- << " a" << that << " -> n" << that
- << " [style=dashed, color=grey, arrowhead=none];\n";
- }
- static const bool kPrintDispatchTable = false;
- void DotPrinter::VisitChoice(ChoiceNode* that) {
- if (kPrintDispatchTable) {
- os_ << " n" << that << " [shape=Mrecord, label=\"";
- TableEntryHeaderPrinter header_printer(os_);
- that->GetTable(ignore_case_)->ForEach(&header_printer);
- os_ << "\"]\n";
- PrintAttributes(that);
- TableEntryBodyPrinter body_printer(os_, that);
- that->GetTable(ignore_case_)->ForEach(&body_printer);
- } else {
- os_ << " n" << that << " [shape=Mrecord, label=\"?\"];\n";
- for (int i = 0; i < that->alternatives()->length(); i++) {
- GuardedAlternative alt = that->alternatives()->at(i);
- os_ << " n" << that << " -> n" << alt.node();
- }
- }
- for (int i = 0; i < that->alternatives()->length(); i++) {
- GuardedAlternative alt = that->alternatives()->at(i);
- alt.node()->Accept(this);
- }
- }
- void DotPrinter::VisitText(TextNode* that) {
- Zone* zone = that->zone();
- os_ << " n" << that << " [label=\"";
- for (int i = 0; i < that->elements()->length(); i++) {
- if (i > 0) os_ << " ";
- TextElement elm = that->elements()->at(i);
- switch (elm.text_type()) {
- case TextElement::ATOM: {
- Vector<const uc16> data = elm.atom()->data();
- for (int i = 0; i < data.length(); i++) {
- os_ << static_cast<char>(data[i]);
- }
- break;
- }
- case TextElement::CHAR_CLASS: {
- RegExpCharacterClass* node = elm.char_class();
- os_ << "[";
- if (node->is_negated()) os_ << "^";
- for (int j = 0; j < node->ranges(zone)->length(); j++) {
- CharacterRange range = node->ranges(zone)->at(j);
- os_ << AsUC16(range.from()) << "-" << AsUC16(range.to());
- }
- os_ << "]";
- break;
- }
- default:
- UNREACHABLE();
- }
- }
- os_ << "\", shape=box, peripheries=2];\n";
- PrintAttributes(that);
- os_ << " n" << that << " -> n" << that->on_success() << ";\n";
- Visit(that->on_success());
- }
- void DotPrinter::VisitBackReference(BackReferenceNode* that) {
- os_ << " n" << that << " [label=\"$" << that->start_register() << "..$"
- << that->end_register() << "\", shape=doubleoctagon];\n";
- PrintAttributes(that);
- os_ << " n" << that << " -> n" << that->on_success() << ";\n";
- Visit(that->on_success());
- }
- void DotPrinter::VisitEnd(EndNode* that) {
- os_ << " n" << that << " [style=bold, shape=point];\n";
- PrintAttributes(that);
- }
- void DotPrinter::VisitAssertion(AssertionNode* that) {
- os_ << " n" << that << " [";
- switch (that->assertion_type()) {
- case AssertionNode::AT_END:
- os_ << "label=\"$\", shape=septagon";
- break;
- case AssertionNode::AT_START:
- os_ << "label=\"^\", shape=septagon";
- break;
- case AssertionNode::AT_BOUNDARY:
- os_ << "label=\"\\b\", shape=septagon";
- break;
- case AssertionNode::AT_NON_BOUNDARY:
- os_ << "label=\"\\B\", shape=septagon";
- break;
- case AssertionNode::AFTER_NEWLINE:
- os_ << "label=\"(?<=\\n)\", shape=septagon";
- break;
- }
- os_ << "];\n";
- PrintAttributes(that);
- RegExpNode* successor = that->on_success();
- os_ << " n" << that << " -> n" << successor << ";\n";
- Visit(successor);
- }
- void DotPrinter::VisitAction(ActionNode* that) {
- os_ << " n" << that << " [";
- switch (that->action_type_) {
- case ActionNode::SET_REGISTER:
- os_ << "label=\"$" << that->data_.u_store_register.reg
- << ":=" << that->data_.u_store_register.value << "\", shape=octagon";
- break;
- case ActionNode::INCREMENT_REGISTER:
- os_ << "label=\"$" << that->data_.u_increment_register.reg
- << "++\", shape=octagon";
- break;
- case ActionNode::STORE_POSITION:
- os_ << "label=\"$" << that->data_.u_position_register.reg
- << ":=$pos\", shape=octagon";
- break;
- case ActionNode::BEGIN_SUBMATCH:
- os_ << "label=\"$" << that->data_.u_submatch.current_position_register
- << ":=$pos,begin\", shape=septagon";
- break;
- case ActionNode::POSITIVE_SUBMATCH_SUCCESS:
- os_ << "label=\"escape\", shape=septagon";
- break;
- case ActionNode::EMPTY_MATCH_CHECK:
- os_ << "label=\"$" << that->data_.u_empty_match_check.start_register
- << "=$pos?,$" << that->data_.u_empty_match_check.repetition_register
- << "<" << that->data_.u_empty_match_check.repetition_limit
- << "?\", shape=septagon";
- break;
- case ActionNode::CLEAR_CAPTURES: {
- os_ << "label=\"clear $" << that->data_.u_clear_captures.range_from
- << " to $" << that->data_.u_clear_captures.range_to
- << "\", shape=septagon";
- break;
- }
- }
- os_ << "];\n";
- PrintAttributes(that);
- RegExpNode* successor = that->on_success();
- os_ << " n" << that << " -> n" << successor << ";\n";
- Visit(successor);
- }
- class DispatchTableDumper {
- public:
- explicit DispatchTableDumper(OStream& os) : os_(os) {}
- void Call(uc16 key, DispatchTable::Entry entry);
- private:
- OStream& os_;
- };
- void DispatchTableDumper::Call(uc16 key, DispatchTable::Entry entry) {
- os_ << "[" << AsUC16(key) << "-" << AsUC16(entry.to()) << "]: {";
- OutSet* set = entry.out_set();
- bool first = true;
- for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
- if (set->Get(i)) {
- if (first) {
- first = false;
- } else {
- os_ << ", ";
- }
- os_ << i;
- }
- }
- os_ << "}\n";
- }
- void DispatchTable::Dump() {
- OFStream os(stderr);
- DispatchTableDumper dumper(os);
- tree()->ForEach(&dumper);
- }
- void RegExpEngine::DotPrint(const char* label,
- RegExpNode* node,
- bool ignore_case) {
- OFStream os(stdout);
- DotPrinter printer(os, ignore_case);
- printer.PrintNode(label, node);
- }
- #endif // DEBUG
- // -------------------------------------------------------------------
- // Tree to graph conversion
- RegExpNode* RegExpAtom::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- ZoneList<TextElement>* elms =
- new(compiler->zone()) ZoneList<TextElement>(1, compiler->zone());
- elms->Add(TextElement::Atom(this), compiler->zone());
- return new(compiler->zone()) TextNode(elms, on_success);
- }
- RegExpNode* RegExpText::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return new(compiler->zone()) TextNode(elements(), on_success);
- }
- static bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
- const int* special_class,
- int length) {
- length--; // Remove final 0x10000.
- DCHECK(special_class[length] == 0x10000);
- DCHECK(ranges->length() != 0);
- DCHECK(length != 0);
- DCHECK(special_class[0] != 0);
- if (ranges->length() != (length >> 1) + 1) {
- return false;
- }
- CharacterRange range = ranges->at(0);
- if (range.from() != 0) {
- return false;
- }
- for (int i = 0; i < length; i += 2) {
- if (special_class[i] != (range.to() + 1)) {
- return false;
- }
- range = ranges->at((i >> 1) + 1);
- if (special_class[i+1] != range.from()) {
- return false;
- }
- }
- if (range.to() != 0xffff) {
- return false;
- }
- return true;
- }
- static bool CompareRanges(ZoneList<CharacterRange>* ranges,
- const int* special_class,
- int length) {
- length--; // Remove final 0x10000.
- DCHECK(special_class[length] == 0x10000);
- if (ranges->length() * 2 != length) {
- return false;
- }
- for (int i = 0; i < length; i += 2) {
- CharacterRange range = ranges->at(i >> 1);
- if (range.from() != special_class[i] ||
- range.to() != special_class[i + 1] - 1) {
- return false;
- }
- }
- return true;
- }
- bool RegExpCharacterClass::is_standard(Zone* zone) {
- // TODO(lrn): Remove need for this function, by not throwing away information
- // along the way.
- if (is_negated_) {
- return false;
- }
- if (set_.is_standard()) {
- return true;
- }
- if (CompareRanges(set_.ranges(zone), kSpaceRanges, kSpaceRangeCount)) {
- set_.set_standard_set_type('s');
- return true;
- }
- if (CompareInverseRanges(set_.ranges(zone), kSpaceRanges, kSpaceRangeCount)) {
- set_.set_standard_set_type('S');
- return true;
- }
- if (CompareInverseRanges(set_.ranges(zone),
- kLineTerminatorRanges,
- kLineTerminatorRangeCount)) {
- set_.set_standard_set_type('.');
- return true;
- }
- if (CompareRanges(set_.ranges(zone),
- kLineTerminatorRanges,
- kLineTerminatorRangeCount)) {
- set_.set_standard_set_type('n');
- return true;
- }
- if (CompareRanges(set_.ranges(zone), kWordRanges, kWordRangeCount)) {
- set_.set_standard_set_type('w');
- return true;
- }
- if (CompareInverseRanges(set_.ranges(zone), kWordRanges, kWordRangeCount)) {
- set_.set_standard_set_type('W');
- return true;
- }
- return false;
- }
- RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return new(compiler->zone()) TextNode(this, on_success);
- }
- RegExpNode* RegExpDisjunction::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- ZoneList<RegExpTree*>* alternatives = this->alternatives();
- int length = alternatives->length();
- ChoiceNode* result =
- new(compiler->zone()) ChoiceNode(length, compiler->zone());
- for (int i = 0; i < length; i++) {
- GuardedAlternative alternative(alternatives->at(i)->ToNode(compiler,
- on_success));
- result->AddAlternative(alternative);
- }
- return result;
- }
- RegExpNode* RegExpQuantifier::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return ToNode(min(),
- max(),
- is_greedy(),
- body(),
- compiler,
- on_success);
- }
- // Scoped object to keep track of how much we unroll quantifier loops in the
- // regexp graph generator.
- class RegExpExpansionLimiter {
- public:
- static const int kMaxExpansionFactor = 6;
- RegExpExpansionLimiter(RegExpCompiler* compiler, int factor)
- : compiler_(compiler),
- saved_expansion_factor_(compiler->current_expansion_factor()),
- ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) {
- DCHECK(factor > 0);
- if (ok_to_expand_) {
- if (factor > kMaxExpansionFactor) {
- // Avoid integer overflow of the current expansion factor.
- ok_to_expand_ = false;
- compiler->set_current_expansion_factor(kMaxExpansionFactor + 1);
- } else {
- int new_factor = saved_expansion_factor_ * factor;
- ok_to_expand_ = (new_factor <= kMaxExpansionFactor);
- compiler->set_current_expansion_factor(new_factor);
- }
- }
- }
- ~RegExpExpansionLimiter() {
- compiler_->set_current_expansion_factor(saved_expansion_factor_);
- }
- bool ok_to_expand() { return ok_to_expand_; }
- private:
- RegExpCompiler* compiler_;
- int saved_expansion_factor_;
- bool ok_to_expand_;
- DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpExpansionLimiter);
- };
- RegExpNode* RegExpQuantifier::ToNode(int min,
- int max,
- bool is_greedy,
- RegExpTree* body,
- RegExpCompiler* compiler,
- RegExpNode* on_success,
- bool not_at_start) {
- // x{f, t} becomes this:
- //
- // (r++)<-.
- // | `
- // | (x)
- // v ^
- // (r=0)-->(?)---/ [if r < t]
- // |
- // [if r >= f] \----> ...
- //
- // 15.10.2.5 RepeatMatcher algorithm.
- // The parser has already eliminated the case where max is 0. In the case
- // where max_match is zero the parser has removed the quantifier if min was
- // > 0 and removed the atom if min was 0. See AddQuantifierToAtom.
- // If we know that we cannot match zero length then things are a little
- // simpler since we don't need to make the special zero length match check
- // from step 2.1. If the min and max are small we can unroll a little in
- // this case.
- static const int kMaxUnrolledMinMatches = 3; // Unroll (foo)+ and (foo){3,}
- static const int kMaxUnrolledMaxMatches = 3; // Unroll (foo)? and (foo){x,3}
- if (max == 0) return on_success; // This can happen due to recursion.
- bool body_can_be_empty = (body->min_match() == 0);
- int body_start_reg = RegExpCompiler::kNoRegister;
- Interval capture_registers = body->CaptureRegisters();
- bool needs_capture_clearing = !capture_registers.is_empty();
- Zone* zone = compiler->zone();
- if (body_can_be_empty) {
- body_start_reg = compiler->AllocateRegister();
- } else if (FLAG_regexp_optimization && !needs_capture_clearing) {
- // Only unroll if there are no captures and the body can't be
- // empty.
- {
- RegExpExpansionLimiter limiter(
- compiler, min + ((max != min) ? 1 : 0));
- if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
- int new_max = (max == kInfinity) ? max : max - min;
- // Recurse once to get the loop or optional matches after the fixed
- // ones.
- RegExpNode* answer = ToNode(
- 0, new_max, is_greedy, body, compiler, on_success, true);
- // Unroll the forced matches from 0 to min. This can cause chains of
- // TextNodes (which the parser does not generate). These should be
- // combined if it turns out they hinder good code generation.
- for (int i = 0; i < min; i++) {
- answer = body->ToNode(compiler, answer);
- }
- return answer;
- }
- }
- if (max <= kMaxUnrolledMaxMatches && min == 0) {
- DCHECK(max > 0); // Due to the 'if' above.
- RegExpExpansionLimiter limiter(compiler, max);
- if (limiter.ok_to_expand()) {
- // Unroll the optional matches up to max.
- RegExpNode* answer = on_success;
- for (int i = 0; i < max; i++) {
- ChoiceNode* alternation = new(zone) ChoiceNode(2, zone);
- if (is_greedy) {
- alternation->AddAlternative(
- GuardedAlternative(body->ToNode(compiler, answer)));
- alternation->AddAlternative(GuardedAlternative(on_success));
- } else {
- alternation->AddAlternative(GuardedAlternative(on_success));
- alternation->AddAlternative(
- GuardedAlternative(body->ToNode(compiler, answer)));
- }
- answer = alternation;
- if (not_at_start) alternation->set_not_at_start();
- }
- return answer;
- }
- }
- }
- bool has_min = min > 0;
- bool has_max = max < RegExpTree::kInfinity;
- bool needs_counter = has_min || has_max;
- int reg_ctr = needs_counter
- ? compiler->AllocateRegister()
- : RegExpCompiler::kNoRegister;
- LoopChoiceNode* center = new(zone) LoopChoiceNode(body->min_match() == 0,
- zone);
- if (not_at_start) center->set_not_at_start();
- RegExpNode* loop_return = needs_counter
- ? static_cast<RegExpNode*>(ActionNode::IncrementRegister(reg_ctr, center))
- : static_cast<RegExpNode*>(center);
- if (body_can_be_empty) {
- // If the body can be empty we need to check if it was and then
- // backtrack.
- loop_return = ActionNode::EmptyMatchCheck(body_start_reg,
- reg_ctr,
- min,
- loop_return);
- }
- RegExpNode* body_node = body->ToNode(compiler, loop_return);
- if (body_can_be_empty) {
- // If the body can be empty we need to store the start position
- // so we can bail out if it was empty.
- body_node = ActionNode::StorePosition(body_start_reg, false, body_node);
- }
- if (needs_capture_clearing) {
- // Before entering the body of this loop we need to clear captures.
- body_node = ActionNode::ClearCaptures(capture_registers, body_node);
- }
- GuardedAlternative body_alt(body_node);
- if (has_max) {
- Guard* body_guard =
- new(zone) Guard(reg_ctr, Guard::LT, max);
- body_alt.AddGuard(body_guard, zone);
- }
- GuardedAlternative rest_alt(on_success);
- if (has_min) {
- Guard* rest_guard = new(compiler->zone()) Guard(reg_ctr, Guard::GEQ, min);
- rest_alt.AddGuard(rest_guard, zone);
- }
- if (is_greedy) {
- center->AddLoopAlternative(body_alt);
- center->AddContinueAlternative(rest_alt);
- } else {
- center->AddContinueAlternative(rest_alt);
- center->AddLoopAlternative(body_alt);
- }
- if (needs_counter) {
- return ActionNode::SetRegister(reg_ctr, 0, center);
- } else {
- return center;
- }
- }
- RegExpNode* RegExpAssertion::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- NodeInfo info;
- Zone* zone = compiler->zone();
- switch (assertion_type()) {
- case START_OF_LINE:
- return AssertionNode::AfterNewline(on_success);
- case START_OF_INPUT:
- return AssertionNode::AtStart(on_success);
- case BOUNDARY:
- return AssertionNode::AtBoundary(on_success);
- case NON_BOUNDARY:
- return AssertionNode::AtNonBoundary(on_success);
- case END_OF_INPUT:
- return AssertionNode::AtEnd(on_success);
- case END_OF_LINE: {
- // Compile $ in multiline regexps as an alternation with a positive
- // lookahead in one side and an end-of-input on the other side.
- // We need two registers for the lookahead.
- int stack_pointer_register = compiler->AllocateRegister();
- int position_register = compiler->AllocateRegister();
- // The ChoiceNode to distinguish between a newline and end-of-input.
- ChoiceNode* result = new(zone) ChoiceNode(2, zone);
- // Create a newline atom.
- ZoneList<CharacterRange>* newline_ranges =
- new(zone) ZoneList<CharacterRange>(3, zone);
- CharacterRange::AddClassEscape('n', newline_ranges, zone);
- RegExpCharacterClass* newline_atom = new(zone) RegExpCharacterClass('n');
- TextNode* newline_matcher = new(zone) TextNode(
- newline_atom,
- ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
- position_register,
- 0, // No captures inside.
- -1, // Ignored if no captures.
- on_success));
- // Create an end-of-input matcher.
- RegExpNode* end_of_line = ActionNode::BeginSubmatch(
- stack_pointer_register,
- position_register,
- newline_matcher);
- // Add the two alternatives to the ChoiceNode.
- GuardedAlternative eol_alternative(end_of_line);
- result->AddAlternative(eol_alternative);
- GuardedAlternative end_alternative(AssertionNode::AtEnd(on_success));
- result->AddAlternative(end_alternative);
- return result;
- }
- default:
- UNREACHABLE();
- }
- return on_success;
- }
- RegExpNode* RegExpBackReference::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return new(compiler->zone())
- BackReferenceNode(RegExpCapture::StartRegister(index()),
- RegExpCapture::EndRegister(index()),
- on_success);
- }
- RegExpNode* RegExpEmpty::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return on_success;
- }
- RegExpNode* RegExpLookahead::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- int stack_pointer_register = compiler->AllocateRegister();
- int position_register = compiler->AllocateRegister();
- const int registers_per_capture = 2;
- const int register_of_first_capture = 2;
- int register_count = capture_count_ * registers_per_capture;
- int register_start =
- register_of_first_capture + capture_from_ * registers_per_capture;
- RegExpNode* success;
- if (is_positive()) {
- RegExpNode* node = ActionNode::BeginSubmatch(
- stack_pointer_register,
- position_register,
- body()->ToNode(
- compiler,
- ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
- position_register,
- register_count,
- register_start,
- on_success)));
- return node;
- } else {
- // We use a ChoiceNode for a negative lookahead because it has most of
- // the characteristics we need. It has the body of the lookahead as its
- // first alternative and the expression after the lookahead of the second
- // alternative. If the first alternative succeeds then the
- // NegativeSubmatchSuccess will unwind the stack including everything the
- // choice node set up and backtrack. If the first alternative fails then
- // the second alternative is tried, which is exactly the desired result
- // for a negative lookahead. The NegativeLookaheadChoiceNode is a special
- // ChoiceNode that knows to ignore the first exit when calculating quick
- // checks.
- Zone* zone = compiler->zone();
- GuardedAlternative body_alt(
- body()->ToNode(
- compiler,
- success = new(zone) NegativeSubmatchSuccess(stack_pointer_register,
- position_register,
- register_count,
- register_start,
- zone)));
- ChoiceNode* choice_node =
- new(zone) NegativeLookaheadChoiceNode(body_alt,
- GuardedAlternative(on_success),
- zone);
- return ActionNode::BeginSubmatch(stack_pointer_register,
- position_register,
- choice_node);
- }
- }
- RegExpNode* RegExpCapture::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- return ToNode(body(), index(), compiler, on_success);
- }
- RegExpNode* RegExpCapture::ToNode(RegExpTree* body,
- int index,
- RegExpCompiler* compiler,
- RegExpNode* on_success) {
- int start_reg = RegExpCapture::StartRegister(index);
- int end_reg = RegExpCapture::EndRegister(index);
- RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success);
- RegExpNode* body_node = body->ToNode(compiler, store_end);
- return ActionNode::StorePosition(start_reg, true, body_node);
- }
- RegExpNode* RegExpAlternative::ToNode(RegExpCompiler* compiler,
- RegExpNode* on_success) {
- ZoneList<RegExpTree*>* children = nodes();
- RegExpNode* current = on_success;
- for (int i = children->length() - 1; i >= 0; i--) {
- current = children->at(i)->ToNode(compiler, current);
- }
- return current;
- }
- static void AddClass(const int* elmv,
- int elmc,
- ZoneList<CharacterRange>* ranges,
- Zone* zone) {
- elmc--;
- DCHECK(elmv[elmc] == 0x10000);
- for (int i = 0; i < elmc; i += 2) {
- DCHECK(elmv[i] < elmv[i + 1]);
- ranges->Add(CharacterRange(elmv[i], elmv[i + 1] - 1), zone);
- }
- }
- static void AddClassNegated(const int *elmv,
- int elmc,
- ZoneList<CharacterRange>* ranges,
- Zone* zone) {
- elmc--;
- DCHECK(elmv[elmc] == 0x10000);
- DCHECK(elmv[0] != 0x0000);
- DCHECK(elmv[elmc-1] != String::kMaxUtf16CodeUnit);
- uc16 last = 0x0000;
- for (int i = 0; i < elmc; i += 2) {
- DCHECK(last <= elmv[i] - 1);
- DCHECK(elmv[i] < elmv[i + 1]);
- ranges->Add(CharacterRange(last, elmv[i] - 1), zone);
- last = elmv[i + 1];
- }
- ranges->Add(CharacterRange(last, String::kMaxUtf16CodeUnit), zone);
- }
- void CharacterRange::AddClassEscape(uc16 type,
- ZoneList<CharacterRange>* ranges,
- Zone* zone) {
- switch (type) {
- case 's':
- AddClass(kSpaceRanges, kSpaceRangeCount, ranges, zone);
- break;
- case 'S':
- AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges, zone);
- break;
- case 'w':
- AddClass(kWordRanges, kWordRangeCount, ranges, zone);
- break;
- case 'W':
- AddClassNegated(kWordRanges, kWordRangeCount, ranges, zone);
- break;
- case 'd':
- AddClass(kDigitRanges, kDigitRangeCount, ranges, zone);
- break;
- case 'D':
- AddClassNegated(kDigitRanges, kDigitRangeCount, ranges, zone);
- break;
- case '.':
- AddClassNegated(kLineTerminatorRanges,
- kLineTerminatorRangeCount,
- ranges,
- zone);
- break;
- // This is not a character range as defined by the spec but a
- // convenient shorthand for a character class that matches any
- // character.
- case '*':
- ranges->Add(CharacterRange::Everything(), zone);
- break;
- // This is the set of characters matched by the $ and ^ symbols
- // in multiline mode.
- case 'n':
- AddClass(kLineTerminatorRanges,
- kLineTerminatorRangeCount,
- ranges,
- zone);
- break;
- default:
- UNREACHABLE();
- }
- }
- Vector<const int> CharacterRange::GetWordBounds() {
- return Vector<const int>(kWordRanges, kWordRangeCount - 1);
- }
- class CharacterRangeSplitter {
- public:
- CharacterRangeSplitter(ZoneList<CharacterRange>** included,
- ZoneList<CharacterRange>** excluded,
- Zone* zone)
- : included_(included),
- excluded_(excluded),
- zone_(zone) { }
- void Call(uc16 from, DispatchTable::Entry entry);
- static const int kInBase = 0;
- static const int kInOverlay = 1;
- private:
- ZoneList<CharacterRange>** included_;
- ZoneList<CharacterRange>** excluded_;
- Zone* zone_;
- };
- void CharacterRangeSplitter::Call(uc16 from, DispatchTable::Entry entry) {
- if (!entry.out_set()->Get(kInBase)) return;
- ZoneList<CharacterRange>** target = entry.out_set()->Get(kInOverlay)
- ? included_
- : excluded_;
- if (*target == NULL) *target = new(zone_) ZoneList<CharacterRange>(2, zone_);
- (*target)->Add(CharacterRange(entry.from(), entry.to()), zone_);
- }
- void CharacterRange::Split(ZoneList<CharacterRange>* base,
- Vector<const int> overlay,
- ZoneList<CharacterRange>** included,
- ZoneList<CharacterRange>** excluded,
- Zone* zone) {
- DCHECK_EQ(NULL, *included);
- DCHECK_EQ(NULL, *excluded);
- DispatchTable table(zone);
- for (int i = 0; i < base->length(); i++)
- table.AddRange(base->at(i), CharacterRangeSplitter::kInBase, zone);
- for (int i = 0; i < overlay.length(); i += 2) {
- table.AddRange(CharacterRange(overlay[i], overlay[i + 1] - 1),
- CharacterRangeSplitter::kInOverlay, zone);
- }
- CharacterRangeSplitter callback(included, excluded, zone);
- table.ForEach(&callback);
- }
- void CharacterRange::AddCaseEquivalents(ZoneList<CharacterRange>* ranges,
- bool is_ascii,
- Zone* zone) {
- Isolate* isolate = zone->isolate();
- uc16 bottom = from();
- uc16 top = to();
- if (is_ascii && !RangeContainsLatin1Equivalents(*this)) {
- if (bottom > String::kMaxOneByteCharCode) return;
- if (top > String::kMaxOneByteCharCode) top = String::kMaxOneByteCharCode;
- }
- unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- if (top == bottom) {
- // If this is a singleton we just expand the one character.
- int length = isolate->jsregexp_uncanonicalize()->get(bottom, '\0', chars);
- for (int i = 0; i < length; i++) {
- uc32 chr = chars[i];
- if (chr != bottom) {
- ranges->Add(CharacterRange::Singleton(chars[i]), zone);
- }
- }
- } else {
- // If this is a range we expand the characters block by block,
- // expanding contiguous subranges (blocks) one at a time.
- // The approach is as follows. For a given start character we
- // look up the remainder of the block that contains it (represented
- // by the end point), for instance we find 'z' if the character
- // is 'c'. A block is characterized by the property
- // that all characters uncanonicalize in the same way, except that
- // each entry in the result is incremented by the distance from the first
- // element. So a-z is a block because 'a' uncanonicalizes to ['a', 'A'] and
- // the k'th letter uncanonicalizes to ['a' + k, 'A' + k].
- // Once we've found the end point we look up its uncanonicalization
- // and produce a range for each element. For instance for [c-f]
- // we look up ['z', 'Z'] and produce [c-f] and [C-F]. We then only
- // add a range if it is not already contained in the input, so [c-f]
- // will be skipped but [C-F] will be added. If this range is not
- // completely contained in a block we do this for all the blocks
- // covered by the range (handling characters that is not in a block
- // as a "singleton block").
- unibrow::uchar range[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- int pos = bottom;
- while (pos <= top) {
- int length = isolate->jsregexp_canonrange()->get(pos, '\0', range);
- uc16 block_end;
- if (length == 0) {
- block_end = pos;
- } else {
- DCHECK_EQ(1, length);
- block_end = range[0];
- }
- int end = (block_end > top) ? top : block_end;
- length = isolate->jsregexp_uncanonicalize()->get(block_end, '\0', range);
- for (int i = 0; i < length; i++) {
- uc32 c = range[i];
- uc16 range_from = c - (block_end - pos);
- uc16 range_to = c - (block_end - end);
- if (!(bottom <= range_from && range_to <= top)) {
- ranges->Add(CharacterRange(range_from, range_to), zone);
- }
- }
- pos = end + 1;
- }
- }
- }
- bool CharacterRange::IsCanonical(ZoneList<CharacterRange>* ranges) {
- DCHECK_NOT_NULL(ranges);
- int n = ranges->length();
- if (n <= 1) return true;
- int max = ranges->at(0).to();
- for (int i = 1; i < n; i++) {
- CharacterRange next_range = ranges->at(i);
- if (next_range.from() <= max + 1) return false;
- max = next_range.to();
- }
- return true;
- }
- ZoneList<CharacterRange>* CharacterSet::ranges(Zone* zone) {
- if (ranges_ == NULL) {
- ranges_ = new(zone) ZoneList<CharacterRange>(2, zone);
- CharacterRange::AddClassEscape(standard_set_type_, ranges_, zone);
- }
- return ranges_;
- }
- // Move a number of elements in a zonelist to another position
- // in the same list. Handles overlapping source and target areas.
- static void MoveRanges(ZoneList<CharacterRange>* list,
- int from,
- int to,
- int count) {
- // Ranges are potentially overlapping.
- if (from < to) {
- for (int i = count - 1; i >= 0; i--) {
- list->at(to + i) = list->at(from + i);
- }
- } else {
- for (int i = 0; i < count; i++) {
- list->at(to + i) = list->at(from + i);
- }
- }
- }
- static int InsertRangeInCanonicalList(ZoneList<CharacterRange>* list,
- int count,
- CharacterRange insert) {
- // Inserts a range into list[0..count[, which must be sorted
- // by from value and non-overlapping and non-adjacent, using at most
- // list[0..count] for the result. Returns the number of resulting
- // canonicalized ranges. Inserting a range may collapse existing ranges into
- // fewer ranges, so the return value can be anything in the range 1..count+1.
- uc16 from = insert.from();
- uc16 to = insert.to();
- int start_pos = 0;
- int end_pos = count;
- for (int i = count - 1; i >= 0; i--) {
- CharacterRange current = list->at(i);
- if (current.from() > to + 1) {
- end_pos = i;
- } else if (current.to() + 1 < from) {
- start_pos = i + 1;
- break;
- }
- }
- // Inserted range overlaps, or is adjacent to, ranges at positions
- // [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are
- // not affected by the insertion.
- // If start_pos == end_pos, the range must be inserted before start_pos.
- // if start_pos < end_pos, the entire range from start_pos to end_pos
- // must be merged with the insert range.
- if (start_pos == end_pos) {
- // Insert between existing ranges at position start_pos.
- if (start_pos < count) {
- MoveRanges(list, start_pos, start_pos + 1, count - start_pos);
- }
- list->at(start_pos) = insert;
- return count + 1;
- }
- if (start_pos + 1 == end_pos) {
- // Replace single existing range at position start_pos.
- CharacterRange to_replace = list->at(start_pos);
- int new_from = Min(to_replace.from(), from);
- int new_to = Max(to_replace.to(), to);
- list->at(start_pos) = CharacterRange(new_from, new_to);
- return count;
- }
- // Replace a number of existing ranges from start_pos to end_pos - 1.
- // Move the remaining ranges down.
- int new_from = Min(list->at(start_pos).from(), from);
- int new_to = Max(list->at(end_pos - 1).to(), to);
- if (end_pos < count) {
- MoveRanges(list, end_pos, start_pos + 1, count - end_pos);
- }
- list->at(start_pos) = CharacterRange(new_from, new_to);
- return count - (end_pos - start_pos) + 1;
- }
- void CharacterSet::Canonicalize() {
- // Special/default classes are always considered canonical. The result
- // of calling ranges() will be sorted.
- if (ranges_ == NULL) return;
- CharacterRange::Canonicalize(ranges_);
- }
- void CharacterRange::Canonicalize(ZoneList<CharacterRange>* character_ranges) {
- if (character_ranges->length() <= 1) return;
- // Check whether ranges are already canonical (increasing, non-overlapping,
- // non-adjacent).
- int n = character_ranges->length();
- int max = character_ranges->at(0).to();
- int i = 1;
- while (i < n) {
- CharacterRange current = character_ranges->at(i);
- if (current.from() <= max + 1) {
- break;
- }
- max = current.to();
- i++;
- }
- // Canonical until the i'th range. If that's all of them, we are done.
- if (i == n) return;
- // The ranges at index i and forward are not canonicalized. Make them so by
- // doing the equivalent of insertion sort (inserting each into the previous
- // list, in order).
- // Notice that inserting a range can reduce the number of ranges in the
- // result due to combining of adjacent and overlapping ranges.
- int read = i; // Range to insert.
- int num_canonical = i; // Length of canonicalized part of list.
- do {
- num_canonical = InsertRangeInCanonicalList(character_ranges,
- num_canonical,
- character_ranges->at(read));
- read++;
- } while (read < n);
- character_ranges->Rewind(num_canonical);
- DCHECK(CharacterRange::IsCanonical(character_ranges));
- }
- void CharacterRange::Negate(ZoneList<CharacterRange>* ranges,
- ZoneList<CharacterRange>* negated_ranges,
- Zone* zone) {
- DCHECK(CharacterRange::IsCanonical(ranges));
- DCHECK_EQ(0, negated_ranges->length());
- int range_count = ranges->length();
- uc16 from = 0;
- int i = 0;
- if (range_count > 0 && ranges->at(0).from() == 0) {
- from = ranges->at(0).to();
- i = 1;
- }
- while (i < range_count) {
- CharacterRange range = ranges->at(i);
- negated_ranges->Add(CharacterRange(from + 1, range.from() - 1), zone);
- from = range.to();
- i++;
- }
- if (from < String::kMaxUtf16CodeUnit) {
- negated_ranges->Add(CharacterRange(from + 1, String::kMaxUtf16CodeUnit),
- zone);
- }
- }
- // -------------------------------------------------------------------
- // Splay tree
- OutSet* OutSet::Extend(unsigned value, Zone* zone) {
- if (Get(value))
- return this;
- if (successors(zone) != NULL) {
- for (int i = 0; i < successors(zone)->length(); i++) {
- OutSet* successor = successors(zone)->at(i);
- if (successor->Get(value))
- return successor;
- }
- } else {
- successors_ = new(zone) ZoneList<OutSet*>(2, zone);
- }
- OutSet* result = new(zone) OutSet(first_, remaining_);
- result->Set(value, zone);
- successors(zone)->Add(result, zone);
- return result;
- }
- void OutSet::Set(unsigned value, Zone *zone) {
- if (value < kFirstLimit) {
- first_ |= (1 << value);
- } else {
- if (remaining_ == NULL)
- remaining_ = new(zone) ZoneList<unsigned>(1, zone);
- if (remaining_->is_empty() || !remaining_->Contains(value))
- remaining_->Add(value, zone);
- }
- }
- bool OutSet::Get(unsigned value) const {
- if (value < kFirstLimit) {
- return (first_ & (1 << value)) != 0;
- } else if (remaining_ == NULL) {
- return false;
- } else {
- return remaining_->Contains(value);
- }
- }
- const uc16 DispatchTable::Config::kNoKey = unibrow::Utf8::kBadChar;
- void DispatchTable::AddRange(CharacterRange full_range, int value,
- Zone* zone) {
- CharacterRange current = full_range;
- if (tree()->is_empty()) {
- // If this is the first range we just insert into the table.
- ZoneSplayTree<Config>::Locator loc;
- DCHECK_RESULT(tree()->Insert(current.from(), &loc));
- loc.set_value(Entry(current.from(), current.to(),
- empty()->Extend(value, zone)));
- return;
- }
- // First see if there is a range to the left of this one that
- // overlaps.
- ZoneSplayTree<Config>::Locator loc;
- if (tree()->FindGreatestLessThan(current.from(), &loc)) {
- Entry* entry = &loc.value();
- // If we've found a range that overlaps with this one, and it
- // starts strictly to the left of this one, we have to fix it
- // because the following code only handles ranges that start on
- // or after the start point of the range we're adding.
- if (entry->from() < current.from() && entry->to() >= current.from()) {
- // Snap the overlapping range in half around the start point of
- // the range we're adding.
- CharacterRange left(entry->from(), current.from() - 1);
- CharacterRange right(current.from(), entry->to());
- // The left part of the overlapping range doesn't overlap.
- // Truncate the whole entry to be just the left part.
- entry->set_to(left.to());
- // The right part is the one that overlaps. We add this part
- // to the map and let the next step deal with merging it with
- // the range we're adding.
- ZoneSplayTree<Config>::Locator loc;
- DCHECK_RESULT(tree()->Insert(right.from(), &loc));
- loc.set_value(Entry(right.from(),
- right.to(),
- entry->out_set()));
- }
- }
- while (current.is_valid()) {
- if (tree()->FindLeastGreaterThan(current.from(), &loc) &&
- (loc.value().from() <= current.to()) &&
- (loc.value().to() >= current.from())) {
- Entry* entry = &loc.value();
- // We have overlap. If there is space between the start point of
- // the range we're adding and where the overlapping range starts
- // then we have to add a range covering just that space.
- if (current.from() < entry->from()) {
- ZoneSplayTree<Config>::Locator ins;
- DCHECK_RESULT(tree()->Insert(current.from(), &ins));
- ins.set_value(Entry(current.from(),
- entry->from() - 1,
- empty()->Extend(value, zone)));
- current.set_from(entry->from());
- }
- DCHECK_EQ(current.from(), entry->from());
- // If the overlapping range extends beyond the one we want to add
- // we have to snap the right part off and add it separately.
- if (entry->to() > current.to()) {
- ZoneSplayTree<Config>::Locator ins;
- DCHECK_RESULT(tree()->Insert(current.to() + 1, &ins));
- ins.set_value(Entry(current.to() + 1,
- entry->to(),
- entry->out_set()));
- entry->set_to(current.to());
- }
- DCHECK(entry->to() <= current.to());
- // The overlapping range is now completely contained by the range
- // we're adding so we can just update it and move the start point
- // of the range we're adding just past it.
- entry->AddValue(value, zone);
- // Bail out if the last interval ended at 0xFFFF since otherwise
- // adding 1 will wrap around to 0.
- if (entry->to() == String::kMaxUtf16CodeUnit)
- break;
- DCHECK(entry->to() + 1 > current.from());
- current.set_from(entry->to() + 1);
- } else {
- // There is no overlap so we can just add the range
- ZoneSplayTree<Config>::Locator ins;
- DCHECK_RESULT(tree()->Insert(current.from(), &ins));
- ins.set_value(Entry(current.from(),
- current.to(),
- empty()->Extend(value, zone)));
- break;
- }
- }
- }
- OutSet* DispatchTable::Get(uc16 value) {
- ZoneSplayTree<Config>::Locator loc;
- if (!tree()->FindGreatestLessThan(value, &loc))
- return empty();
- Entry* entry = &loc.value();
- if (value <= entry->to())
- return entry->out_set();
- else
- return empty();
- }
- // -------------------------------------------------------------------
- // Analysis
- void Analysis::EnsureAnalyzed(RegExpNode* that) {
- StackLimitCheck check(that->zone()->isolate());
- if (check.HasOverflowed()) {
- fail("Stack overflow");
- return;
- }
- if (that->info()->been_analyzed || that->info()->being_analyzed)
- return;
- that->info()->being_analyzed = true;
- that->Accept(this);
- that->info()->being_analyzed = false;
- that->info()->been_analyzed = true;
- }
- void Analysis::VisitEnd(EndNode* that) {
- // nothing to do
- }
- void TextNode::CalculateOffsets() {
- int element_count = elements()->length();
- // Set up the offsets of the elements relative to the start. This is a fixed
- // quantity since a TextNode can only contain fixed-width things.
- int cp_offset = 0;
- for (int i = 0; i < element_count; i++) {
- TextElement& elm = elements()->at(i);
- elm.set_cp_offset(cp_offset);
- cp_offset += elm.length();
- }
- }
- void Analysis::VisitText(TextNode* that) {
- if (ignore_case_) {
- that->MakeCaseIndependent(is_ascii_);
- }
- EnsureAnalyzed(that->on_success());
- if (!has_failed()) {
- that->CalculateOffsets();
- }
- }
- void Analysis::VisitAction(ActionNode* that) {
- RegExpNode* target = that->on_success();
- EnsureAnalyzed(target);
- if (!has_failed()) {
- // If the next node is interested in what it follows then this node
- // has to be interested too so it can pass the information on.
- that->info()->AddFromFollowing(target->info());
- }
- }
- void Analysis::VisitChoice(ChoiceNode* that) {
- NodeInfo* info = that->info();
- for (int i = 0; i < that->alternatives()->length(); i++) {
- RegExpNode* node = that->alternatives()->at(i).node();
- EnsureAnalyzed(node);
- if (has_failed()) return;
- // Anything the following nodes need to know has to be known by
- // this node also, so it can pass it on.
- info->AddFromFollowing(node->info());
- }
- }
- void Analysis::VisitLoopChoice(LoopChoiceNode* that) {
- NodeInfo* info = that->info();
- for (int i = 0; i < that->alternatives()->length(); i++) {
- RegExpNode* node = that->alternatives()->at(i).node();
- if (node != that->loop_node()) {
- EnsureAnalyzed(node);
- if (has_failed()) return;
- info->AddFromFollowing(node->info());
- }
- }
- // Check the loop last since it may need the value of this node
- // to get a correct result.
- EnsureAnalyzed(that->loop_node());
- if (!has_failed()) {
- info->AddFromFollowing(that->loop_node()->info());
- }
- }
- void Analysis::VisitBackReference(BackReferenceNode* that) {
- EnsureAnalyzed(that->on_success());
- }
- void Analysis::VisitAssertion(AssertionNode* that) {
- EnsureAnalyzed(that->on_success());
- }
- void BackReferenceNode::FillInBMInfo(int offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- // Working out the set of characters that a backreference can match is too
- // hard, so we just say that any character can match.
- bm->SetRest(offset);
- SaveBMInfo(bm, not_at_start, offset);
- }
- STATIC_ASSERT(BoyerMoorePositionInfo::kMapSize ==
- RegExpMacroAssembler::kTableSize);
- void ChoiceNode::FillInBMInfo(int offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- ZoneList<GuardedAlternative>* alts = alternatives();
- budget = (budget - 1) / alts->length();
- for (int i = 0; i < alts->length(); i++) {
- GuardedAlternative& alt = alts->at(i);
- if (alt.guards() != NULL && alt.guards()->length() != 0) {
- bm->SetRest(offset); // Give up trying to fill in info.
- SaveBMInfo(bm, not_at_start, offset);
- return;
- }
- alt.node()->FillInBMInfo(offset, budget, bm, not_at_start);
- }
- SaveBMInfo(bm, not_at_start, offset);
- }
- void TextNode::FillInBMInfo(int initial_offset,
- int budget,
- BoyerMooreLookahead* bm,
- bool not_at_start) {
- if (initial_offset >= bm->length()) return;
- int offset = initial_offset;
- int max_char = bm->max_char();
- for (int i = 0; i < elements()->length(); i++) {
- if (offset >= bm->length()) {
- if (initial_offset == 0) set_bm_info(not_at_start, bm);
- return;
- }
- TextElement text = elements()->at(i);
- if (text.text_type() == TextElement::ATOM) {
- RegExpAtom* atom = text.atom();
- for (int j = 0; j < atom->length(); j++, offset++) {
- if (offset >= bm->length()) {
- if (initial_offset == 0) set_bm_info(not_at_start, bm);
- return;
- }
- uc16 character = atom->data()[j];
- if (bm->compiler()->ignore_case()) {
- unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
- int length = GetCaseIndependentLetters(
- Isolate::Current(),
- character,
- bm->max_char() == String::kMaxOneByteCharCode,
- chars);
- for (int j = 0; j < length; j++) {
- bm->Set(offset, chars[j]);
- }
- } else {
- if (character <= max_char) bm->Set(offset, character);
- }
- }
- } else {
- DCHECK_EQ(TextElement::CHAR_CLASS, text.text_type());
- RegExpCharacterClass* char_class = text.char_class();
- ZoneList<CharacterRange>* ranges = char_class->ranges(zone());
- if (char_class->is_negated()) {
- bm->SetAll(offset);
- } else {
- for (int k = 0; k < ranges->length(); k++) {
- CharacterRange& range = ranges->at(k);
- if (range.from() > max_char) continue;
- int to = Min(max_char, static_cast<int>(range.to()));
- bm->SetInterval(offset, Interval(range.from(), to));
- }
- }
- offset++;
- }
- }
- if (offset >= bm->length()) {
- if (initial_offset == 0) set_bm_info(not_at_start, bm);
- return;
- }
- on_success()->FillInBMInfo(offset,
- budget - 1,
- bm,
- true); // Not at start after a text node.
- if (initial_offset == 0) set_bm_info(not_at_start, bm);
- }
- // -------------------------------------------------------------------
- // Dispatch table construction
- void DispatchTableConstructor::VisitEnd(EndNode* that) {
- AddRange(CharacterRange::Everything());
- }
- void DispatchTableConstructor::BuildTable(ChoiceNode* node) {
- node->set_being_calculated(true);
- ZoneList<GuardedAlternative>* alternatives = node->alternatives();
- for (int i = 0; i < alternatives->length(); i++) {
- set_choice_index(i);
- alternatives->at(i).node()->Accept(this);
- }
- node->set_being_calculated(false);
- }
- class AddDispatchRange {
- public:
- explicit AddDispatchRange(DispatchTableConstructor* constructor)
- : constructor_(constructor) { }
- void Call(uc32 from, DispatchTable::Entry entry);
- private:
- DispatchTableConstructor* constructor_;
- };
- void AddDispatchRange::Call(uc32 from, DispatchTable::Entry entry) {
- CharacterRange range(from, entry.to());
- constructor_->AddRange(range);
- }
- void DispatchTableConstructor::VisitChoice(ChoiceNode* node) {
- if (node->being_calculated())
- return;
- DispatchTable* table = node->GetTable(ignore_case_);
- AddDispatchRange adder(this);
- table->ForEach(&adder);
- }
- void DispatchTableConstructor::VisitBackReference(BackReferenceNode* that) {
- // TODO(160): Find the node that we refer back to and propagate its start
- // set back to here. For now we just accept anything.
- AddRange(CharacterRange::Everything());
- }
- void DispatchTableConstructor::VisitAssertion(AssertionNode* that) {
- RegExpNode* target = that->on_success();
- target->Accept(this);
- }
- static int CompareRangeByFrom(const CharacterRange* a,
- const CharacterRange* b) {
- return Compare<uc16>(a->from(), b->from());
- }
- void DispatchTableConstructor::AddInverse(ZoneList<CharacterRange>* ranges) {
- ranges->Sort(CompareRangeByFrom);
- uc16 last = 0;
- for (int i = 0; i < ranges->length(); i++) {
- CharacterRange range = ranges->at(i);
- if (last < range.from())
- AddRange(CharacterRange(last, range.from() - 1));
- if (range.to() >= last) {
- if (range.to() == String::kMaxUtf16CodeUnit) {
- return;
- } else {
- last = range.to() + 1;
- }
- }
- }
- AddRange(CharacterRange(last, String::kMaxUtf16CodeUnit));
- }
- void DispatchTableConstructor::VisitText(TextNode* that) {
- TextElement elm = that->elements()->at(0);
- switch (elm.text_type()) {
- case TextElement::ATOM: {
- uc16 c = elm.atom()->data()[0];
- AddRange(CharacterRange(c, c));
- break;
- }
- case TextElement::CHAR_CLASS: {
- RegExpCharacterClass* tree = elm.char_class();
- ZoneList<CharacterRange>* ranges = tree->ranges(that->zone());
- if (tree->is_negated()) {
- AddInverse(ranges);
- } else {
- for (int i = 0; i < ranges->length(); i++)
- AddRange(ranges->at(i));
- }
- break;
- }
- default: {
- UNIMPLEMENTED();
- }
- }
- }
- void DispatchTableConstructor::VisitAction(ActionNode* that) {
- RegExpNode* target = that->on_success();
- target->Accept(this);
- }
- RegExpEngine::CompilationResult RegExpEngine::Compile(
- RegExpCompileData* data,
- bool ignore_case,
- bool is_global,
- bool is_multiline,
- Handle<String> pattern,
- Handle<String> sample_subject,
- bool is_ascii,
- Zone* zone) {
- if ((data->capture_count + 1) * 2 - 1 > RegExpMacroAssembler::kMaxRegister) {
- return IrregexpRegExpTooBig(zone->isolate());
- }
- RegExpCompiler compiler(data->capture_count, ignore_case, is_ascii, zone);
- // Sample some characters from the middle of the string.
- static const int kSampleSize = 128;
- sample_subject = String::Flatten(sample_subject);
- int chars_sampled = 0;
- int half_way = (sample_subject->length() - kSampleSize) / 2;
- for (int i = Max(0, half_way);
- i < sample_subject->length() && chars_sampled < kSampleSize;
- i++, chars_sampled++) {
- compiler.frequency_collator()->CountCharacter(sample_subject->Get(i));
- }
- // Wrap the body of the regexp in capture #0.
- RegExpNode* captured_body = RegExpCapture::ToNode(data->tree,
- 0,
- &compiler,
- compiler.accept());
- RegExpNode* node = captured_body;
- bool is_end_anchored = data->tree->IsAnchoredAtEnd();
- bool is_start_anchored = data->tree->IsAnchoredAtStart();
- int max_length = data->tree->max_match();
- if (!is_start_anchored) {
- // Add a .*? at the beginning, outside the body capture, unless
- // this expression is anchored at the beginning.
- RegExpNode* loop_node =
- RegExpQuantifier::ToNode(0,
- RegExpTree::kInfinity,
- false,
- new(zone) RegExpCharacterClass('*'),
- &compiler,
- captured_body,
- data->contains_anchor);
- if (data->contains_anchor) {
- // Unroll loop once, to take care of the case that might start
- // at the start of input.
- ChoiceNode* first_step_node = new(zone) ChoiceNode(2, zone);
- first_step_node->AddAlternative(GuardedAlternative(captured_body));
- first_step_node->AddAlternative(GuardedAlternative(
- new(zone) TextNode(new(zone) RegExpCharacterClass('*'), loop_node)));
- node = first_step_node;
- } else {
- node = loop_node;
- }
- }
- if (is_ascii) {
- node = node->FilterASCII(RegExpCompiler::kMaxRecursion, ignore_case);
- // Do it again to propagate the new nodes to places where they were not
- // put because they had not been calculated yet.
- if (node != NULL) {
- node = node->FilterASCII(RegExpCompiler::kMaxRecursion, ignore_case);
- }
- }
- if (node == NULL) node = new(zone) EndNode(EndNode::BACKTRACK, zone);
- data->node = node;
- Analysis analysis(ignore_case, is_ascii);
- analysis.EnsureAnalyzed(node);
- if (analysis.has_failed()) {
- const char* error_message = analysis.error_message();
- return CompilationResult(zone->isolate(), error_message);
- }
- // Create the correct assembler for the architecture.
- #ifndef V8_INTERPRETED_REGEXP
- // Native regexp implementation.
- NativeRegExpMacroAssembler::Mode mode =
- is_ascii ? NativeRegExpMacroAssembler::ASCII
- : NativeRegExpMacroAssembler::UC16;
- #if V8_TARGET_ARCH_IA32
- RegExpMacroAssemblerIA32 macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_X64
- RegExpMacroAssemblerX64 macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_ARM
- RegExpMacroAssemblerARM macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_ARM64
- RegExpMacroAssemblerARM64 macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_MIPS
- RegExpMacroAssemblerMIPS macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_MIPS64
- RegExpMacroAssemblerMIPS macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #elif V8_TARGET_ARCH_X87
- RegExpMacroAssemblerX87 macro_assembler(mode, (data->capture_count + 1) * 2,
- zone);
- #else
- #error "Unsupported architecture"
- #endif
- #else // V8_INTERPRETED_REGEXP
- // Interpreted regexp implementation.
- EmbeddedVector<byte, 1024> codes;
- RegExpMacroAssemblerIrregexp macro_assembler(codes, zone);
- #endif // V8_INTERPRETED_REGEXP
- // Inserted here, instead of in Assembler, because it depends on information
- // in the AST that isn't replicated in the Node structure.
- static const int kMaxBacksearchLimit = 1024;
- if (is_end_anchored &&
- !is_start_anchored &&
- max_length < kMaxBacksearchLimit) {
- macro_assembler.SetCurrentPositionFromEnd(max_length);
- }
- if (is_global) {
- macro_assembler.set_global_mode(
- (data->tree->min_match() > 0)
- ? RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK
- : RegExpMacroAssembler::GLOBAL);
- }
- return compiler.Assemble(¯o_assembler,
- node,
- data->capture_count,
- pattern);
- }
- }} // namespace v8::internal