forked from OSchip/llvm-project
84 lines
3.2 KiB
C++
84 lines
3.2 KiB
C++
//===-Caching.cpp - LLVM Link Time Optimizer Cache Handling ---------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the Caching for ThinLTO.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/LTO/Caching.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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using namespace llvm::lto;
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Expected<NativeObjectCache> lto::localCache(StringRef CacheDirectoryPath,
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AddFileFn AddFile) {
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if (std::error_code EC = sys::fs::create_directories(CacheDirectoryPath))
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return errorCodeToError(EC);
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return [=](unsigned Task, StringRef Key) -> AddStreamFn {
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// First, see if we have a cache hit.
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SmallString<64> EntryPath;
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sys::path::append(EntryPath, CacheDirectoryPath, Key);
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if (sys::fs::exists(EntryPath)) {
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AddFile(Task, EntryPath);
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return AddStreamFn();
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}
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// This native object stream is responsible for commiting the resulting
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// file to the cache and calling AddFile to add it to the link.
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struct CacheStream : NativeObjectStream {
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AddFileFn AddFile;
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std::string TempFilename;
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std::string EntryPath;
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unsigned Task;
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CacheStream(std::unique_ptr<raw_pwrite_stream> OS, AddFileFn AddFile,
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std::string TempFilename, std::string EntryPath,
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unsigned Task)
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: NativeObjectStream(std::move(OS)), AddFile(std::move(AddFile)),
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TempFilename(std::move(TempFilename)),
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EntryPath(std::move(EntryPath)), Task(Task) {}
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~CacheStream() {
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// Make sure the file is closed before committing it.
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OS.reset();
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// This is atomic on POSIX systems.
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if (auto EC = sys::fs::rename(TempFilename, EntryPath))
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report_fatal_error(Twine("Failed to rename temporary file ") +
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TempFilename + ": " + EC.message() + "\n");
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AddFile(Task, EntryPath);
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}
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};
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return [=](size_t Task) -> std::unique_ptr<NativeObjectStream> {
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// Write to a temporary to avoid race condition
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int TempFD;
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SmallString<64> TempFilenameModel, TempFilename;
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sys::path::append(TempFilenameModel, CacheDirectoryPath, "Thin-%%%%%%.tmp.o");
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std::error_code EC =
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sys::fs::createUniqueFile(TempFilenameModel, TempFD, TempFilename,
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sys::fs::owner_read | sys::fs::owner_write);
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if (EC) {
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errs() << "Error: " << EC.message() << "\n";
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report_fatal_error("ThinLTO: Can't get a temporary file");
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}
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// This CacheStream will move the temporary file into the cache when done.
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return llvm::make_unique<CacheStream>(
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llvm::make_unique<raw_fd_ostream>(TempFD, /* ShouldClose */ true),
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AddFile, TempFilename.str(), EntryPath.str(), Task);
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};
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};
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}
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