llvm/lib/Bitcode/Writer/BitcodeWriterPass.cpp
Teresa Johnson 7ca333b425 [ThinLTO] Move summary computation from BitcodeWriter to new pass
Summary:
This is the first step in also serializing the index out to LLVM
assembly.

The per-module summary written to bitcode is moved out of the bitcode
writer and to a new analysis pass (ModuleSummaryIndexWrapperPass).
The pass itself uses a new builder class to compute index, and the
builder class is used directly in places where we don't have a pass
manager (e.g. llvm-as).

Because we are computing summaries outside of the bitcode writer, we no
longer can use value ids created by the bitcode writer's
ValueEnumerator. This required changing the reference graph edge type
to use a new ValueInfo class holding a union between a GUID (combined
index) and Value* (permodule index). The Value* are converted to the
appropriate value ID during bitcode writing.

Also, this enables removal of the BitWriter library's dependence on the
Analysis library that was previously required for the summary computation.

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D18763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265941 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-11 13:58:45 +00:00

84 lines
3.0 KiB
C++

//===- BitcodeWriterPass.cpp - Bitcode writing pass -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// BitcodeWriterPass implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Bitcode/BitcodeWriterPass.h"
#include "llvm/Analysis/ModuleSummaryAnalysis.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
using namespace llvm;
PreservedAnalyses BitcodeWriterPass::run(Module &M) {
std::unique_ptr<ModuleSummaryIndex> Index;
if (EmitSummaryIndex)
Index = ModuleSummaryIndexBuilder(&M).takeIndex();
WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, Index.get(),
EmitModuleHash);
return PreservedAnalyses::all();
}
namespace {
class WriteBitcodePass : public ModulePass {
raw_ostream &OS; // raw_ostream to print on
bool ShouldPreserveUseListOrder;
bool EmitSummaryIndex;
bool EmitModuleHash;
public:
static char ID; // Pass identification, replacement for typeid
WriteBitcodePass() : ModulePass(ID), OS(dbgs()) {
initializeWriteBitcodePassPass(*PassRegistry::getPassRegistry());
}
explicit WriteBitcodePass(raw_ostream &o, bool ShouldPreserveUseListOrder,
bool EmitSummaryIndex, bool EmitModuleHash)
: ModulePass(ID), OS(o),
ShouldPreserveUseListOrder(ShouldPreserveUseListOrder),
EmitSummaryIndex(EmitSummaryIndex), EmitModuleHash(EmitModuleHash) {
initializeWriteBitcodePassPass(*PassRegistry::getPassRegistry());
}
const char *getPassName() const override { return "Bitcode Writer"; }
bool runOnModule(Module &M) override {
const ModuleSummaryIndex *Index =
EmitSummaryIndex
? &(getAnalysis<ModuleSummaryIndexWrapperPass>().getIndex())
: nullptr;
WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, Index,
EmitModuleHash);
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
if (EmitSummaryIndex)
AU.addRequired<ModuleSummaryIndexWrapperPass>();
}
};
}
char WriteBitcodePass::ID = 0;
INITIALIZE_PASS_BEGIN(WriteBitcodePass, "write-bitcode", "Write Bitcode", false,
true)
INITIALIZE_PASS_DEPENDENCY(ModuleSummaryIndexWrapperPass)
INITIALIZE_PASS_END(WriteBitcodePass, "write-bitcode", "Write Bitcode", false,
true)
ModulePass *llvm::createBitcodeWriterPass(raw_ostream &Str,
bool ShouldPreserveUseListOrder,
bool EmitSummaryIndex, bool EmitModuleHash) {
return new WriteBitcodePass(Str, ShouldPreserveUseListOrder,
EmitSummaryIndex, EmitModuleHash);
}