mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-29 13:24:57 +01:00
Chandler CarruthandJon Ross-Perkins
8d1d491ad0
This removes the separately built and installed LLD binary. The symlinks used by Clang when directly invoking LLD now point back to the main `carbon-busybox` binary and dispatch through the newly added subcommand. With this change we're down to shipping a single busybox binary in the toolchain, removing duplicate installed copies of LLD and all its LLVM dependencies. =] The LLD subcommand works a bit differently from the `clang` subcommand because the CLI for LLD is specific to which platform flavor of linker is being invoked. As part of this, I've extracted some of the common functionality in the Clang runner into a base class that can be re-used. I expect to use this again in a follow-up change to add subcommands to run other LLVM tools. --------- Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
114 lines
3.9 KiB
C++
114 lines
3.9 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/lld_subcommand.h"
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#include "llvm/TargetParser/Host.h"
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#include "llvm/TargetParser/Triple.h"
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#include "toolchain/driver/lld_runner.h"
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namespace Carbon {
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auto LldOptions::Build(CommandLine::CommandBuilder& b) -> void {
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// We want to select a default platform based on the default target. Since
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// that requires some dynamic inspection of the target, do that here.
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std::string default_target = llvm::sys::getDefaultTargetTriple();
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llvm::Triple default_triple(default_target);
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switch (default_triple.getObjectFormat()) {
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case llvm::Triple::MachO:
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platform = Platform::MachO;
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break;
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// We default to the GNU or Unix platform as ELF is a plausible default
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// and LLD doesn't support any generic invocations.
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default:
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case llvm::Triple::ELF:
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platform = Platform::Elf;
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break;
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}
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b.AddOneOfOption(
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{
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.name = "platform",
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.help = R"""(
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Platform linking style to use. The default is selected to match the default
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target's platform.
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)""",
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},
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[&](auto& arg_b) {
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arg_b.SetOneOf(
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{
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arg_b.OneOfValue("elf", Platform::Elf),
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// Some of LLD documentation uses "Unix" or "GNU", so
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// include an alias here.
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arg_b.OneOfValue("gnu", Platform::Elf),
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arg_b.OneOfValue("unix", Platform::Elf),
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arg_b.OneOfValue("macho", Platform::MachO),
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// Darwin is also sometimes used, include it as an alias here.
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arg_b.OneOfValue("darwin", Platform::MachO),
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},
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&platform);
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});
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b.AddStringPositionalArg(
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{
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.name = "ARG",
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.help = R"""(
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Arguments passed to LLD.
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)""",
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},
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[&](auto& arg_b) { arg_b.Append(&args); });
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}
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static constexpr CommandLine::CommandInfo SubcommandInfo = {
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.name = "lld",
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.help = R"""(
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Runs LLD with the provided arguments.
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Note that a specific LLD platform must be selected, and it is actually that
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particular platform's LLD-driver that is run with the arguments. There is no
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generic LLD command line.
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For a given platform, this is equivalent to running that platform's LLD alias
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directly, and provides the full command line interface.
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Use `carbon lld --platform=elf -- ARGS` to separate the `ARGS` forwarded to LLD
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from the flags passed to the Carbon subcommand.
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Note that typically it is better to use a higher level command to link code,
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such as invoking `carbon link` with the relevant flags. However, this subcommand
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supports when you already have a specific invocation using existing command line
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syntaxes, as well as testing and debugging of the underlying tool.
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)""",
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};
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LldSubcommand::LldSubcommand() : DriverSubcommand(SubcommandInfo) {}
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// TODO: This lacks a lot of features from the main driver code. We may need to
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// add more.
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// https://github.com/llvm/llvm-project/blob/main/clang/tools/driver/driver.cpp
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auto LldSubcommand::Run(DriverEnv& driver_env) -> DriverResult {
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LldRunner runner(driver_env.installation, driver_env.vlog_stream);
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// Don't run LLD when fuzzing, as we're not currently in a good position to
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// debug and fix fuzzer-found bugs within LLD.
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if (driver_env.fuzzing) {
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CARBON_DIAGNOSTIC(
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LLDFuzzingDisallowed, Error,
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"preventing fuzzing of `lld` subcommand due to external library");
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driver_env.emitter.Emit(LLDFuzzingDisallowed);
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return {.success = false};
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}
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switch (options_.platform) {
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case LldOptions::Platform::Elf:
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return {.success = runner.ElfLink(options_.args)};
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case LldOptions::Platform::MachO:
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return {.success = runner.MachOLink(options_.args)};
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}
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CARBON_FATAL("Failed to find and run a valid LLD platform link!");
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}
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} // namespace Carbon
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