/contrib/llvm/tools/lld/tools/lld/lld.cpp
C++ | 169 lines | 112 code | 16 blank | 41 comment | 33 complexity | 9a3884b1a10d99d082e4549bd0afc098 MD5 | raw file
- //===- tools/lld/lld.cpp - Linker Driver Dispatcher -----------------------===//
- //
- // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- // See https://llvm.org/LICENSE.txt for license information.
- // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- //
- //===----------------------------------------------------------------------===//
- //
- // This file contains the main function of the lld executable. The main
- // function is a thin wrapper which dispatches to the platform specific
- // driver.
- //
- // lld is a single executable that contains four different linkers for ELF,
- // COFF, WebAssembly and Mach-O. The main function dispatches according to
- // argv[0] (i.e. command name). The most common name for each target is shown
- // below:
- //
- // - ld.lld: ELF (Unix)
- // - ld64: Mach-O (macOS)
- // - lld-link: COFF (Windows)
- // - ld-wasm: WebAssembly
- //
- // lld can be invoked as "lld" along with "-flavor" option. This is for
- // backward compatibility and not recommended.
- //
- //===----------------------------------------------------------------------===//
- #include "lld/Common/Driver.h"
- #include "lld/Common/Memory.h"
- #include "llvm/ADT/STLExtras.h"
- #include "llvm/ADT/SmallVector.h"
- #include "llvm/ADT/StringSwitch.h"
- #include "llvm/ADT/Triple.h"
- #include "llvm/ADT/Twine.h"
- #include "llvm/Support/CommandLine.h"
- #include "llvm/Support/InitLLVM.h"
- #include "llvm/Support/Path.h"
- #include <cstdlib>
- using namespace lld;
- using namespace llvm;
- using namespace llvm::sys;
- enum Flavor {
- Invalid,
- Gnu, // -flavor gnu
- WinLink, // -flavor link
- Darwin, // -flavor darwin
- Wasm, // -flavor wasm
- };
- LLVM_ATTRIBUTE_NORETURN static void die(const Twine &s) {
- errs() << s << "\n";
- exit(1);
- }
- static Flavor getFlavor(StringRef s) {
- return StringSwitch<Flavor>(s)
- .CasesLower("ld", "ld.lld", "gnu", Gnu)
- .CasesLower("wasm", "ld-wasm", Wasm)
- .CaseLower("link", WinLink)
- .CasesLower("ld64", "ld64.lld", "darwin", Darwin)
- .Default(Invalid);
- }
- static cl::TokenizerCallback getDefaultQuotingStyle() {
- if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
- return cl::TokenizeWindowsCommandLine;
- return cl::TokenizeGNUCommandLine;
- }
- static bool isPETargetName(StringRef s) {
- return s == "i386pe" || s == "i386pep" || s == "thumb2pe" || s == "arm64pe";
- }
- static bool isPETarget(std::vector<const char *> &v) {
- for (auto it = v.begin(); it + 1 != v.end(); ++it) {
- if (StringRef(*it) != "-m")
- continue;
- return isPETargetName(*(it + 1));
- }
- // Expand response files (arguments in the form of @<filename>)
- // to allow detecting the -m argument from arguments in them.
- SmallVector<const char *, 256> expandedArgs(v.data(), v.data() + v.size());
- cl::ExpandResponseFiles(saver, getDefaultQuotingStyle(), expandedArgs);
- for (auto it = expandedArgs.begin(); it + 1 != expandedArgs.end(); ++it) {
- if (StringRef(*it) != "-m")
- continue;
- return isPETargetName(*(it + 1));
- }
- return false;
- }
- static Flavor parseProgname(StringRef progname) {
- #if __APPLE__
- // Use Darwin driver for "ld" on Darwin.
- if (progname == "ld")
- return Darwin;
- #endif
- #if LLVM_ON_UNIX
- // Use GNU driver for "ld" on other Unix-like system.
- if (progname == "ld")
- return Gnu;
- #endif
- // Progname may be something like "lld-gnu". Parse it.
- SmallVector<StringRef, 3> v;
- progname.split(v, "-");
- for (StringRef s : v)
- if (Flavor f = getFlavor(s))
- return f;
- return Invalid;
- }
- static Flavor parseFlavor(std::vector<const char *> &v) {
- // Parse -flavor option.
- if (v.size() > 1 && v[1] == StringRef("-flavor")) {
- if (v.size() <= 2)
- die("missing arg value for '-flavor'");
- Flavor f = getFlavor(v[2]);
- if (f == Invalid)
- die("Unknown flavor: " + StringRef(v[2]));
- v.erase(v.begin() + 1, v.begin() + 3);
- return f;
- }
- // Deduct the flavor from argv[0].
- StringRef arg0 = path::filename(v[0]);
- if (arg0.endswith_lower(".exe"))
- arg0 = arg0.drop_back(4);
- return parseProgname(arg0);
- }
- // If this function returns true, lld calls _exit() so that it quickly
- // exits without invoking destructors of globally allocated objects.
- //
- // We don't want to do that if we are running tests though, because
- // doing that breaks leak sanitizer. So, lit sets this environment variable,
- // and we use it to detect whether we are running tests or not.
- static bool canExitEarly() { return StringRef(getenv("LLD_IN_TEST")) != "1"; }
- /// Universal linker main(). This linker emulates the gnu, darwin, or
- /// windows linker based on the argv[0] or -flavor option.
- int main(int argc, const char **argv) {
- InitLLVM x(argc, argv);
- std::vector<const char *> args(argv, argv + argc);
- #ifdef __FreeBSD__
- return !elf::link(args, true);
- #else
- switch (parseFlavor(args)) {
- case Gnu:
- if (isPETarget(args))
- return !mingw::link(args);
- return !elf::link(args, canExitEarly());
- case WinLink:
- return !coff::link(args, canExitEarly());
- case Darwin:
- return !mach_o::link(args, canExitEarly());
- case Wasm:
- return !wasm::link(args, canExitEarly());
- default:
- die("lld is a generic driver.\n"
- "Invoke ld.lld (Unix), ld64.lld (macOS), lld-link (Windows), wasm-ld"
- " (WebAssembly) instead");
- }
- #endif
- }