| //===- 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/Host.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) { |
| llvm::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); |
| switch (parseFlavor(args)) { |
| case Gnu: |
| if (isPETarget(args)) |
| return !mingw::link(args, canExitEarly(), llvm::outs(), llvm::errs()); |
| return !elf::link(args, canExitEarly(), llvm::outs(), llvm::errs()); |
| case WinLink: |
| return !coff::link(args, canExitEarly(), llvm::outs(), llvm::errs()); |
| case Darwin: |
| return !mach_o::link(args, canExitEarly(), llvm::outs(), llvm::errs()); |
| case Wasm: |
| return !wasm::link(args, canExitEarly(), llvm::outs(), llvm::errs()); |
| default: |
| die("lld is a generic driver.\n" |
| "Invoke ld.lld (Unix), ld64.lld (macOS), lld-link (Windows), wasm-ld" |
| " (WebAssembly) instead"); |
| } |
| } |