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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
3070e5cfc6
When finding an executable, this validates that the returned binary is a symlink back to the same thing as /proc/self/exe, also using that as a fallback for different things. Looking back at #3912, we started using `findProgramByName` in order to avoid path canonicalization done by `GetMainExecutable`. That created issues as in #5096, wherein an `argv[0]` that's not explicit enough (`llvm-symbolizer` instead of the full path, done in [LLVM's Signals.cpp](https://github.com/llvm/llvm-project/blob/4f60f45130c6bd96c79e468fe9927a29af760f56/llvm/lib/Support/Signals.cpp#L198)) leads to incorrect results (finding an `llvm-symbolizer` in `$PATH`). One option to fix this would be to patch LLVM to provide an absolute path for `llvm-symbolizer`. However, I'll suggest that passing a filename in `argv[0]` is not terribly uncommon, and could be a migration limitation if we force it. The failure mode is also opaque; for example: ``` $ /bin/sh -c "exec -a llvm-symbolizer ./bazel-bin/toolchain/carbon" error: expected carbon-busybox symlink at `/usr/lib/llvm-19/bin/llvm-symbolizer` ``` Combined with the `setenv` of `LLVM_SYMBOLIZER_PATH` in `busybox_main.cpp`, this is intended to fix #5096.
104 lines
3.8 KiB
C++
104 lines
3.8 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 <unistd.h>
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#include <cstdlib>
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#include <string>
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#include "common/bazel_working_dir.h"
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#include "common/error.h"
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#include "common/init_llvm.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/LLVMDriver.h"
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#include "toolchain/driver/driver.h"
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#include "toolchain/install/busybox_info.h"
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#include "toolchain/install/install_paths.h"
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namespace Carbon {
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// The actual `main` implementation. Can return an exit code or an `Error`
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// (which causes EXIT_FAILRUE).
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static auto Main(int argc, char** argv) -> ErrorOr<int> {
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InitLLVM init_llvm(argc, argv);
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// Start by resolving any symlinks.
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CARBON_ASSIGN_OR_RETURN(auto busybox_info, GetBusyboxInfo(argv[0]));
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auto fs = llvm::vfs::getRealFileSystem();
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// Resolve paths before calling SetWorkingDirForBazel.
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std::string exe_path = busybox_info.bin_path.string();
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const auto install_paths = InstallPaths::MakeExeRelative(exe_path);
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if (install_paths.error()) {
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return Error(*install_paths.error());
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}
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// If `LLVM_SYMBOLIZER_PATH` is unset, sets it. Signals.cpp would do some more
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// path resolution which this overrides in favor of using the busybox itself
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// for symbolization.
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setenv("LLVM_SYMBOLIZER_PATH",
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(install_paths.llvm_install_bin() + "llvm-symbolizer").c_str(),
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/*overwrite=*/0);
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SetWorkingDirForBazel();
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llvm::SmallVector<llvm::StringRef> args;
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args.reserve(argc + 1);
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if (busybox_info.mode) {
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// Map busybox modes to the relevant subcommands with any flags needed to
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// emulate the requested command. Typically, our busyboxed binaries redirect
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// to a specific subcommand with some flags set and then pass the remaining
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// busybox arguments as positional arguments to that subcommand.
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//
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// TODO: Add relevant flags to the `clang` subcommand and add `clang`-based
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// symlinks to this like `clang++`.
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auto subcommand_args =
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llvm::StringSwitch<llvm::SmallVector<llvm::StringRef>>(
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*busybox_info.mode)
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// The `clang` program name used configures the default for its
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// `--driver-mode` flag. The first of these is redundant with the
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// default, but we group it here for clarity.
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.Case("clang", {"clang", "--"})
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.Case("clang++", {"clang", "--", "--driver-mode=g++"})
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.Case("clang-cl", {"clang", "--", "--driver-mode=cl"})
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.Case("clang-cpp", {"clang", "--", "--driver-mode=cpp"})
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// LLD has platform-specific program names that we translate into
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// platform flags.
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.Case("ld.lld", {"lld", "--platform=gnu", "--"})
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.Case("ld64.lld", {"lld", "--platform=darwin", "--"})
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// We also support a number of LLVM tools with a trivial translation
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// to subcommands. If any of these end up needing more advanced
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// translation, that can be factored into the `.def` file to provide custom
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// expansion here.
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#define CARBON_LLVM_TOOL(Id, Name, BinName, MainFn) \
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.Case(BinName, {"llvm", Name, "--"})
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#include "toolchain/base/llvm_tools.def"
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.Default({*busybox_info.mode, "--"});
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args.append(subcommand_args);
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}
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args.append(argv + 1, argv + argc);
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Driver driver(fs, &install_paths, stdin, &llvm::outs(), &llvm::errs(),
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/*fuzzing=*/false, /*enable_leaking=*/true);
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bool success = driver.RunCommand(args).success;
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return success ? EXIT_SUCCESS : EXIT_FAILURE;
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}
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} // namespace Carbon
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auto main(int argc, char** argv) -> int {
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auto result = Carbon::Main(argc, argv);
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if (result.ok()) {
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return *result;
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} else {
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llvm::errs() << "error: " << result.error() << "\n";
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return EXIT_FAILURE;
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}
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}
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