dc85d5263e
This feature is enabled by `-codegen-data-thinlto-two-rounds`, which effectively runs the `-codegen-data-generate` and `-codegen-data-use` in two rounds to enable global outlining with ThinLTO. 1. The first round: Run both optimization + codegen with a scratch output. Before running codegen, we serialize the optimized bitcode modules to a temporary path. 2. From the scratch object files, we merge them into the codegen data. 3. The second round: Read the optimized bitcode modules and start the codegen only this time. Using the codegen data, the machine outliner effectively performs the global outlining. Depends on #90934, #110461 and #110463. This is a patch for https://discourse.llvm.org/t/rfc-enhanced-machine-outliner-part-2-thinlto-nolto/78753.
83 lines
3.4 KiB
C++
83 lines
3.4 KiB
C++
//===-LTOBackend.h - LLVM Link Time Optimizer Backend ---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the "backend" phase of LTO, i.e. it performs
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// optimization and code generation on a loaded module. It is generally used
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// internally by the LTO class but can also be used independently, for example
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// to implement a standalone ThinLTO backend.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LTO_LTOBACKEND_H
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#define LLVM_LTO_LTOBACKEND_H
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#include "llvm/ADT/MapVector.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#include "llvm/IR/ModuleSummaryIndex.h"
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#include "llvm/LTO/LTO.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Transforms/IPO/FunctionImport.h"
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namespace llvm {
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class BitcodeModule;
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class Error;
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class Module;
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class Target;
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namespace lto {
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/// Runs middle-end LTO optimizations on \p Mod.
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bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
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bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
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const ModuleSummaryIndex *ImportSummary,
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const std::vector<uint8_t> &CmdArgs);
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/// Runs a regular LTO backend. The regular LTO backend can also act as the
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/// regular LTO phase of ThinLTO, which may need to access the combined index.
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Error backend(const Config &C, AddStreamFn AddStream,
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unsigned ParallelCodeGenParallelismLevel, Module &M,
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ModuleSummaryIndex &CombinedIndex);
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/// Runs a ThinLTO backend.
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/// If \p ModuleMap is not nullptr, all the module files to be imported have
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/// already been mapped to memory and the corresponding BitcodeModule objects
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/// are saved in the ModuleMap. If \p ModuleMap is nullptr, module files will
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/// be mapped to memory on demand and at any given time during importing, only
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/// one source module will be kept open at the most. If \p CodeGenOnly is true,
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/// the backend will skip optimization and only perform code generation. If
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/// \p IRAddStream is not nullptr, it will be called just before code generation
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/// to serialize the optimized IR.
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Error thinBackend(const Config &C, unsigned Task, AddStreamFn AddStream,
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Module &M, const ModuleSummaryIndex &CombinedIndex,
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const FunctionImporter::ImportMapTy &ImportList,
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const GVSummaryMapTy &DefinedGlobals,
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MapVector<StringRef, BitcodeModule> *ModuleMap,
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bool CodeGenOnly, AddStreamFn IRAddStream = nullptr,
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const std::vector<uint8_t> &CmdArgs = std::vector<uint8_t>());
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Error finalizeOptimizationRemarks(
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std::unique_ptr<ToolOutputFile> DiagOutputFile);
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/// Returns the BitcodeModule that is ThinLTO.
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BitcodeModule *findThinLTOModule(MutableArrayRef<BitcodeModule> BMs);
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/// Variant of the above.
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Expected<BitcodeModule> findThinLTOModule(MemoryBufferRef MBRef);
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/// Distributed ThinLTO: collect the referenced modules based on
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/// module summary and initialize ImportList. Returns false if the
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/// operation failed.
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bool initImportList(const Module &M, const ModuleSummaryIndex &CombinedIndex,
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FunctionImporter::ImportMapTy &ImportList);
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}
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}
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#endif
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