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llvm-mirror/include/llvm/LTO/LTOBackend.h
Wei Mi d8e32b94e9 [ThinLTO] During module importing, close one source module before open
another one for distributed mode.

Currently during module importing, ThinLTO opens all the source modules,
collect functions to be imported and append them to the destination module,
then leave all the modules open through out the lto backend pipeline. This
patch refactors it in the way that one source module will be closed before
another source module is opened. All the source modules will be closed after
importing phase is done. It will save some amount of memory when there are
many source modules to be imported.

Note that this patch only changes the distributed thinlto mode. For in
process thinlto mode, one source module is shared acorss different thinlto
backend threads so it is not changed in this patch.

Differential Revision: https://reviews.llvm.org/D99554
2021-03-30 14:37:29 -07:00

79 lines
3.1 KiB
C++

//===-LTOBackend.h - LLVM Link Time Optimizer Backend ---------------------===//
//
// 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 implements the "backend" phase of LTO, i.e. it performs
// optimization and code generation on a loaded module. It is generally used
// internally by the LTO class but can also be used independently, for example
// to implement a standalone ThinLTO backend.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LTO_LTOBACKEND_H
#define LLVM_LTO_LTOBACKEND_H
#include "llvm/ADT/MapVector.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/LTO/LTO.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/IPO/FunctionImport.h"
namespace llvm {
class BitcodeModule;
class Error;
class Module;
class Target;
namespace lto {
/// Runs middle-end LTO optimizations on \p Mod.
bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
const ModuleSummaryIndex *ImportSummary,
const std::vector<uint8_t> &CmdArgs);
/// Runs a regular LTO backend. The regular LTO backend can also act as the
/// regular LTO phase of ThinLTO, which may need to access the combined index.
Error backend(const Config &C, AddStreamFn AddStream,
unsigned ParallelCodeGenParallelismLevel, Module &M,
ModuleSummaryIndex &CombinedIndex);
/// Runs a ThinLTO backend.
/// If \p ModuleMap is not nullptr, all the module files to be imported have
/// already been mapped to memory and the corresponding BitcodeModule objects
/// are saved in the ModuleMap. If \p ModuleMap is nullptr, module files will
/// be mapped to memory on demand and at any given time during importing, only
/// one source module will be kept open at the most.
Error thinBackend(const Config &C, unsigned Task, AddStreamFn AddStream,
Module &M, const ModuleSummaryIndex &CombinedIndex,
const FunctionImporter::ImportMapTy &ImportList,
const GVSummaryMapTy &DefinedGlobals,
MapVector<StringRef, BitcodeModule> *ModuleMap,
const std::vector<uint8_t> &CmdArgs = std::vector<uint8_t>());
Error finalizeOptimizationRemarks(
std::unique_ptr<ToolOutputFile> DiagOutputFile);
/// Returns the BitcodeModule that is ThinLTO.
BitcodeModule *findThinLTOModule(MutableArrayRef<BitcodeModule> BMs);
/// Variant of the above.
Expected<BitcodeModule> findThinLTOModule(MemoryBufferRef MBRef);
/// Distributed ThinLTO: collect the referenced modules based on
/// module summary and initialize ImportList. Returns false if the
/// operation failed.
bool initImportList(const Module &M, const ModuleSummaryIndex &CombinedIndex,
FunctionImporter::ImportMapTy &ImportList);
}
}
#endif