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josh11bandJosh L
47bfa375af
As discussed in #4530 . This required switching to using `llvm::IntrusiveRefCntPtr` in a number of places. --------- Co-authored-by: Josh L <josh11b@users.noreply.github.com>
122 lines
4.2 KiB
C++
122 lines
4.2 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/driver/link_subcommand.h"
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#include "llvm/TargetParser/Triple.h"
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#include "toolchain/driver/clang_runner.h"
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namespace Carbon {
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auto LinkOptions::Build(CommandLine::CommandBuilder& b) -> void {
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b.AddStringPositionalArg(
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{
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.name = "OBJECT_FILE",
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.help = R"""(
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The input object files.
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)""",
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},
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[&](auto& arg_b) {
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arg_b.Required(true);
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arg_b.Append(&object_filenames);
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});
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b.AddStringOption(
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{
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.name = "output",
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.value_name = "FILE",
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.help = R"""(
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The linked file name. The output is always a linked binary.
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)""",
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},
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[&](auto& arg_b) {
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arg_b.Required(true);
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arg_b.Set(&output_filename);
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});
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codegen_options.Build(b);
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}
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static void AddOSFlags(llvm::StringRef target,
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llvm::SmallVectorImpl<llvm::StringRef>& args) {
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llvm::Triple triple(target);
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switch (triple.getOS()) {
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case llvm::Triple::Darwin:
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case llvm::Triple::MacOSX:
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// On macOS we need to set the sysroot to a viable SDK. Currently, this
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// hard codes the path to be the unversioned symlink. The prefix is also
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// hard coded in Homebrew and so this seems likely to work reasonably
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// well. Homebrew and I suspect the Xcode Clang both have this hard coded
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// at build time, so this seems reasonably safe but we can revisit if/when
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// needed.
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args.push_back(
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"--sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk");
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// We also need to insist on a modern linker, otherwise the driver tries
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// too old and deprecated flags. The specific number here comes from an
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// inspection of the Clang driver source code to understand where features
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// were enabled, and this appears to be the latest version to control
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// driver behavior.
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//
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// TODO: We should replace this with use of `lld` eventually.
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args.push_back("-mlinker-version=705");
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break;
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default:
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// By default, just let the Clang driver handle everything.
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break;
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}
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}
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static constexpr CommandLine::CommandInfo SubcommandInfo = {
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.name = "link",
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.help = R"""(
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Link Carbon executables.
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This subcommand links Carbon executables by combining object files.
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TODO: Support linking binary libraries, both archives and shared libraries.
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TODO: Support linking against binary libraries.
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)""",
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};
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LinkSubcommand::LinkSubcommand() : DriverSubcommand(SubcommandInfo) {}
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auto LinkSubcommand::Run(DriverEnv& driver_env) -> DriverResult {
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// TODO: Currently we use the Clang driver to link. This works well on Unix
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// OSes but we likely need to directly build logic to invoke `link.exe` on
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// Windows where `cl.exe` doesn't typically cover that logic.
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// Use a reasonably large small vector here to minimize allocations. We expect
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// to link reasonably large numbers of object files.
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llvm::SmallVector<llvm::StringRef, 128> clang_args;
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// We link using a C++ mode of the driver.
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clang_args.push_back("--driver-mode=g++");
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// Use LLD, which we provide in our install directory, for linking.
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clang_args.push_back("-fuse-ld=lld");
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// Disable linking the C++ standard library until can build and ship it as
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// part of the Carbon toolchain. This clearly won't work once we get into
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// interop, but for now it avoids spurious failures and distraction. The plan
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// is to build and bundle libc++ at which point we can replace this with
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// pointing at our bundled library.
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// TODO: Replace this when ready.
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clang_args.push_back("-nostdlib++");
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// Add OS-specific flags based on the target.
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AddOSFlags(options_.codegen_options.target, clang_args);
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clang_args.push_back("-o");
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clang_args.push_back(options_.output_filename);
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clang_args.append(options_.object_filenames.begin(),
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options_.object_filenames.end());
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ClangRunner runner(driver_env.installation, options_.codegen_options.target,
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driver_env.fs, driver_env.vlog_stream);
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return {.success = runner.Run(clang_args)};
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}
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} // namespace Carbon
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