/thirdparty/breakpad/common/dwarf/cfi_assembler.cc
http://github.com/tomahawk-player/tomahawk · C++ · 198 lines · 124 code · 26 blank · 48 comment · 14 complexity · 95c23c97c3828f31e365d330b48bc46d MD5 · raw file
- // Copyright (c) 2010, Google Inc.
- // All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are
- // met:
- //
- // * Redistributions of source code must retain the above copyright
- // notice, this list of conditions and the following disclaimer.
- // * Redistributions in binary form must reproduce the above
- // copyright notice, this list of conditions and the following disclaimer
- // in the documentation and/or other materials provided with the
- // distribution.
- // * Neither the name of Google Inc. nor the names of its
- // contributors may be used to endorse or promote products derived from
- // this software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
- // cfi_assembler.cc: Implementation of google_breakpad::CFISection class.
- // See cfi_assembler.h for details.
- #include "common/dwarf/cfi_assembler.h"
- #include <assert.h>
- #include <stdlib.h>
- namespace google_breakpad {
- using dwarf2reader::DwarfPointerEncoding;
-
- CFISection &CFISection::CIEHeader(u_int64_t code_alignment_factor,
- int data_alignment_factor,
- unsigned return_address_register,
- u_int8_t version,
- const string &augmentation,
- bool dwarf64) {
- assert(!entry_length_);
- entry_length_ = new PendingLength();
- in_fde_ = false;
- if (dwarf64) {
- D32(kDwarf64InitialLengthMarker);
- D64(entry_length_->length);
- entry_length_->start = Here();
- D64(eh_frame_ ? kEHFrame64CIEIdentifier : kDwarf64CIEIdentifier);
- } else {
- D32(entry_length_->length);
- entry_length_->start = Here();
- D32(eh_frame_ ? kEHFrame32CIEIdentifier : kDwarf32CIEIdentifier);
- }
- D8(version);
- AppendCString(augmentation);
- ULEB128(code_alignment_factor);
- LEB128(data_alignment_factor);
- if (version == 1)
- D8(return_address_register);
- else
- ULEB128(return_address_register);
- return *this;
- }
- CFISection &CFISection::FDEHeader(Label cie_pointer,
- u_int64_t initial_location,
- u_int64_t address_range,
- bool dwarf64) {
- assert(!entry_length_);
- entry_length_ = new PendingLength();
- in_fde_ = true;
- fde_start_address_ = initial_location;
- if (dwarf64) {
- D32(0xffffffff);
- D64(entry_length_->length);
- entry_length_->start = Here();
- if (eh_frame_)
- D64(Here() - cie_pointer);
- else
- D64(cie_pointer);
- } else {
- D32(entry_length_->length);
- entry_length_->start = Here();
- if (eh_frame_)
- D32(Here() - cie_pointer);
- else
- D32(cie_pointer);
- }
- EncodedPointer(initial_location);
- // The FDE length in an .eh_frame section uses the same encoding as the
- // initial location, but ignores the base address (selected by the upper
- // nybble of the encoding), as it's a length, not an address that can be
- // made relative.
- EncodedPointer(address_range,
- DwarfPointerEncoding(pointer_encoding_ & 0x0f));
- return *this;
- }
- CFISection &CFISection::FinishEntry() {
- assert(entry_length_);
- Align(address_size_, dwarf2reader::DW_CFA_nop);
- entry_length_->length = Here() - entry_length_->start;
- delete entry_length_;
- entry_length_ = NULL;
- in_fde_ = false;
- return *this;
- }
- CFISection &CFISection::EncodedPointer(u_int64_t address,
- DwarfPointerEncoding encoding,
- const EncodedPointerBases &bases) {
- // Omitted data is extremely easy to emit.
- if (encoding == dwarf2reader::DW_EH_PE_omit)
- return *this;
- // If (encoding & dwarf2reader::DW_EH_PE_indirect) != 0, then we assume
- // that ADDRESS is the address at which the pointer is stored --- in
- // other words, that bit has no effect on how we write the pointer.
- encoding = DwarfPointerEncoding(encoding & ~dwarf2reader::DW_EH_PE_indirect);
- // Find the base address to which this pointer is relative. The upper
- // nybble of the encoding specifies this.
- u_int64_t base;
- switch (encoding & 0xf0) {
- case dwarf2reader::DW_EH_PE_absptr: base = 0; break;
- case dwarf2reader::DW_EH_PE_pcrel: base = bases.cfi + Size(); break;
- case dwarf2reader::DW_EH_PE_textrel: base = bases.text; break;
- case dwarf2reader::DW_EH_PE_datarel: base = bases.data; break;
- case dwarf2reader::DW_EH_PE_funcrel: base = fde_start_address_; break;
- case dwarf2reader::DW_EH_PE_aligned: base = 0; break;
- default: abort();
- };
- // Make ADDRESS relative. Yes, this is appropriate even for "absptr"
- // values; see gcc/unwind-pe.h.
- address -= base;
- // Align the pointer, if required.
- if ((encoding & 0xf0) == dwarf2reader::DW_EH_PE_aligned)
- Align(AddressSize());
- // Append ADDRESS to this section in the appropriate form. For the
- // fixed-width forms, we don't need to differentiate between signed and
- // unsigned encodings, because ADDRESS has already been extended to 64
- // bits before it was passed to us.
- switch (encoding & 0x0f) {
- case dwarf2reader::DW_EH_PE_absptr:
- Address(address);
- break;
- case dwarf2reader::DW_EH_PE_uleb128:
- ULEB128(address);
- break;
- case dwarf2reader::DW_EH_PE_sleb128:
- LEB128(address);
- break;
- case dwarf2reader::DW_EH_PE_udata2:
- case dwarf2reader::DW_EH_PE_sdata2:
- D16(address);
- break;
- case dwarf2reader::DW_EH_PE_udata4:
- case dwarf2reader::DW_EH_PE_sdata4:
- D32(address);
- break;
- case dwarf2reader::DW_EH_PE_udata8:
- case dwarf2reader::DW_EH_PE_sdata8:
- D64(address);
- break;
- default:
- abort();
- }
- return *this;
- };
- const u_int32_t CFISection::kDwarf64InitialLengthMarker;
- const u_int32_t CFISection::kDwarf32CIEIdentifier;
- const u_int64_t CFISection::kDwarf64CIEIdentifier;
- const u_int32_t CFISection::kEHFrame32CIEIdentifier;
- const u_int64_t CFISection::kEHFrame64CIEIdentifier;
- } // namespace google_breakpad