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llvm-mirror/lib/Analysis/ProfileDataLoaderPass.cpp
Bob Wilson 1540efb8f2 Revert "Add LLVMContext::emitWarning methods and use them. <rdar://problem/12867368>"
This reverts r171041. This was a nice idea that didn't work out well.
Clang warnings need to be associated with warning groups so that they can
be selectively disabled, promoted to errors, etc. This simplistic patch didn't
allow for that. Enhancing it to provide some way for the backend to specify
a front-end warning type seems like overkill for the few uses of this, at
least for now.

llvm-svn: 174748
2013-02-08 21:48:29 +00:00

189 lines
7.1 KiB
C++

//===- ProfileDataLoaderPass.cpp - Set branch weight metadata from prof ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass loads profiling data from a dump file and sets branch weight
// metadata.
//
// TODO: Replace all "profile-metadata-loader" strings with "profile-loader"
// once ProfileInfo etc. has been removed.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "profile-metadata-loader"
#include "llvm/Analysis/Passes.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ProfileDataLoader.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
STATISTIC(NumEdgesRead, "The # of edges read.");
STATISTIC(NumTermsAnnotated, "The # of terminator instructions annotated.");
static cl::opt<std::string>
ProfileMetadataFilename("profile-file", cl::init("llvmprof.out"),
cl::value_desc("filename"),
cl::desc("Profile file loaded by -profile-metadata-loader"));
namespace {
/// This pass loads profiling data from a dump file and sets branch weight
/// metadata.
class ProfileMetadataLoaderPass : public ModulePass {
std::string Filename;
public:
static char ID; // Class identification, replacement for typeinfo
explicit ProfileMetadataLoaderPass(const std::string &filename = "")
: ModulePass(ID), Filename(filename) {
initializeProfileMetadataLoaderPassPass(*PassRegistry::getPassRegistry());
if (filename.empty()) Filename = ProfileMetadataFilename;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
virtual const char *getPassName() const {
return "Profile loader";
}
virtual void readEdge(unsigned, ProfileData&, ProfileData::Edge,
ArrayRef<unsigned>);
virtual unsigned matchEdges(Module&, ProfileData&, ArrayRef<unsigned>);
virtual void setBranchWeightMetadata(Module&, ProfileData&);
virtual bool runOnModule(Module &M);
};
} // End of anonymous namespace
char ProfileMetadataLoaderPass::ID = 0;
INITIALIZE_PASS_BEGIN(ProfileMetadataLoaderPass, "profile-metadata-loader",
"Load profile information from llvmprof.out", false, true)
INITIALIZE_PASS_END(ProfileMetadataLoaderPass, "profile-metadata-loader",
"Load profile information from llvmprof.out", false, true)
char &llvm::ProfileMetadataLoaderPassID = ProfileMetadataLoaderPass::ID;
/// createProfileMetadataLoaderPass - This function returns a Pass that loads
/// the profiling information for the module from the specified filename,
/// making it available to the optimizers.
ModulePass *llvm::createProfileMetadataLoaderPass() {
return new ProfileMetadataLoaderPass();
}
ModulePass *llvm::createProfileMetadataLoaderPass(const std::string &Filename) {
return new ProfileMetadataLoaderPass(Filename);
}
/// readEdge - Take the value from a profile counter and assign it to an edge.
void ProfileMetadataLoaderPass::readEdge(unsigned ReadCount,
ProfileData &PB, ProfileData::Edge e,
ArrayRef<unsigned> Counters) {
if (ReadCount >= Counters.size()) return;
unsigned weight = Counters[ReadCount];
assert(weight != ProfileDataLoader::Uncounted);
PB.addEdgeWeight(e, weight);
DEBUG(dbgs() << "-- Read Edge Counter for " << e
<< " (# "<< (ReadCount) << "): "
<< PB.getEdgeWeight(e) << "\n");
}
/// matchEdges - Link every profile counter with an edge.
unsigned ProfileMetadataLoaderPass::matchEdges(Module &M, ProfileData &PB,
ArrayRef<unsigned> Counters) {
if (Counters.size() == 0) return 0;
unsigned ReadCount = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
if (F->isDeclaration()) continue;
DEBUG(dbgs() << "Loading edges in '" << F->getName() << "'\n");
readEdge(ReadCount++, PB, PB.getEdge(0, &F->getEntryBlock()), Counters);
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s) {
readEdge(ReadCount++, PB, PB.getEdge(BB,TI->getSuccessor(s)),
Counters);
}
}
}
return ReadCount;
}
/// setBranchWeightMetadata - Translate the counter values associated with each
/// edge into branch weights for each conditional branch (a branch with 2 or
/// more desinations).
void ProfileMetadataLoaderPass::setBranchWeightMetadata(Module &M,
ProfileData &PB) {
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
if (F->isDeclaration()) continue;
DEBUG(dbgs() << "Setting branch metadata in '" << F->getName() << "'\n");
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
unsigned NumSuccessors = TI->getNumSuccessors();
// If there is only one successor then we can not set a branch
// probability as the target is certain.
if (NumSuccessors < 2) continue;
// Load the weights of all edges leading from this terminator.
DEBUG(dbgs() << "-- Terminator with " << NumSuccessors
<< " successors:\n");
SmallVector<uint32_t, 4> Weights(NumSuccessors);
for (unsigned s = 0 ; s < NumSuccessors ; ++s) {
ProfileData::Edge edge = PB.getEdge(BB, TI->getSuccessor(s));
Weights[s] = (uint32_t)PB.getEdgeWeight(edge);
DEBUG(dbgs() << "---- Edge '" << edge << "' has weight "
<< Weights[s] << "\n");
}
// Set branch weight metadata. This will set branch probabilities of
// 100%/0% if that is true of the dynamic execution.
// BranchProbabilityInfo can account for this when it loads this metadata
// (it gives the unexectuted branch a weight of 1 for the purposes of
// probability calculations).
MDBuilder MDB(TI->getContext());
MDNode *Node = MDB.createBranchWeights(Weights);
TI->setMetadata(LLVMContext::MD_prof, Node);
NumTermsAnnotated++;
}
}
}
bool ProfileMetadataLoaderPass::runOnModule(Module &M) {
ProfileDataLoader PDL("profile-data-loader", Filename);
ProfileData PB;
ArrayRef<unsigned> Counters = PDL.getRawEdgeCounts();
unsigned ReadCount = matchEdges(M, PB, Counters);
if (ReadCount != Counters.size()) {
errs() << "WARNING: profile information is inconsistent with "
<< "the current program!\n";
}
NumEdgesRead = ReadCount;
setBranchWeightMetadata(M, PB);
return ReadCount > 0;
}