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diff --git a/lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp b/lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp
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-//===- OptimalEdgeProfiling.cpp - Insert counters for opt. edge profiling -===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass instruments the specified program with counters for edge profiling.
-// Edge profiling can give a reasonable approximation of the hot paths through a
-// program, and is used for a wide variety of program transformations.
-//
-//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "insert-optimal-edge-profiling"
-#include "llvm/Transforms/Instrumentation.h"
-#include "MaximumSpanningTree.h"
-#include "ProfilingUtils.h"
-#include "llvm/ADT/DenseSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/Passes.h"
-#include "llvm/Analysis/ProfileInfo.h"
-#include "llvm/Analysis/ProfileInfoLoader.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-using namespace llvm;
-
-STATISTIC(NumEdgesInserted, "The # of edges inserted.");
-
-namespace {
- class OptimalEdgeProfiler : public ModulePass {
- bool runOnModule(Module &M);
- public:
- static char ID; // Pass identification, replacement for typeid
- OptimalEdgeProfiler() : ModulePass(ID) {
- initializeOptimalEdgeProfilerPass(*PassRegistry::getPassRegistry());
- }
-
- void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequiredID(ProfileEstimatorPassID);
- AU.addRequired<ProfileInfo>();
- }
-
- virtual const char *getPassName() const {
- return "Optimal Edge Profiler";
- }
- };
-}
-
-char OptimalEdgeProfiler::ID = 0;
-INITIALIZE_PASS_BEGIN(OptimalEdgeProfiler, "insert-optimal-edge-profiling",
- "Insert optimal instrumentation for edge profiling",
- false, false)
-INITIALIZE_PASS_DEPENDENCY(ProfileEstimatorPass)
-INITIALIZE_AG_DEPENDENCY(ProfileInfo)
-INITIALIZE_PASS_END(OptimalEdgeProfiler, "insert-optimal-edge-profiling",
- "Insert optimal instrumentation for edge profiling",
- false, false)
-
-ModulePass *llvm::createOptimalEdgeProfilerPass() {
- return new OptimalEdgeProfiler();
-}
-
-inline static void printEdgeCounter(ProfileInfo::Edge e,
- BasicBlock* b,
- unsigned i) {
- DEBUG(dbgs() << "--Edge Counter for " << (e) << " in " \
- << ((b)?(b)->getName():"0") << " (# " << (i) << ")\n");
-}
-
-bool OptimalEdgeProfiler::runOnModule(Module &M) {
- Function *Main = M.getFunction("main");
- if (Main == 0) {
- errs() << "WARNING: cannot insert edge profiling into a module"
- << " with no main function!\n";
- return false; // No main, no instrumentation!
- }
-
- // NumEdges counts all the edges that may be instrumented. Later on its
- // decided which edges to actually instrument, to achieve optimal profiling.
- // For the entry block a virtual edge (0,entry) is reserved, for each block
- // with no successors an edge (BB,0) is reserved. These edges are necessary
- // to calculate a truly optimal maximum spanning tree and thus an optimal
- // instrumentation.
- unsigned NumEdges = 0;
-
- for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
- if (F->isDeclaration()) continue;
- // Reserve space for (0,entry) edge.
- ++NumEdges;
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
- // Keep track of which blocks need to be instrumented. We don't want to
- // instrument blocks that are added as the result of breaking critical
- // edges!
- if (BB->getTerminator()->getNumSuccessors() == 0) {
- // Reserve space for (BB,0) edge.
- ++NumEdges;
- } else {
- NumEdges += BB->getTerminator()->getNumSuccessors();
- }
- }
- }
-
- // In the profiling output a counter for each edge is reserved, but only few
- // are used. This is done to be able to read back in the profile without
- // calulating the maximum spanning tree again, instead each edge counter that
- // is not used is initialised with -1 to signal that this edge counter has to
- // be calculated from other edge counters on reading the profile info back
- // in.
-
- Type *Int32 = Type::getInt32Ty(M.getContext());
- ArrayType *ATy = ArrayType::get(Int32, NumEdges);
- GlobalVariable *Counters =
- new GlobalVariable(M, ATy, false, GlobalValue::InternalLinkage,
- Constant::getNullValue(ATy), "OptEdgeProfCounters");
- NumEdgesInserted = 0;
-
- std::vector<Constant*> Initializer(NumEdges);
- Constant *Zero = ConstantInt::get(Int32, 0);
- Constant *Uncounted = ConstantInt::get(Int32, ProfileInfoLoader::Uncounted);
-
- // Instrument all of the edges not in MST...
- unsigned i = 0;
- for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
- if (F->isDeclaration()) continue;
- DEBUG(dbgs() << "Working on " << F->getName() << "\n");
-
- // Calculate a Maximum Spanning Tree with the edge weights determined by
- // ProfileEstimator. ProfileEstimator also assign weights to the virtual
- // edges (0,entry) and (BB,0) (for blocks with no successors) and this
- // edges also participate in the maximum spanning tree calculation.
- // The third parameter of MaximumSpanningTree() has the effect that not the
- // actual MST is returned but the edges _not_ in the MST.
-
- ProfileInfo::EdgeWeights ECs =
- getAnalysis<ProfileInfo>(*F).getEdgeWeights(F);
- std::vector<ProfileInfo::EdgeWeight> EdgeVector(ECs.begin(), ECs.end());
- MaximumSpanningTree<BasicBlock> MST(EdgeVector);
- std::stable_sort(MST.begin(), MST.end());
-
- // Check if (0,entry) not in the MST. If not, instrument edge
- // (IncrementCounterInBlock()) and set the counter initially to zero, if
- // the edge is in the MST the counter is initialised to -1.
-
- BasicBlock *entry = &(F->getEntryBlock());
- ProfileInfo::Edge edge = ProfileInfo::getEdge(0, entry);
- if (!std::binary_search(MST.begin(), MST.end(), edge)) {
- printEdgeCounter(edge, entry, i);
- IncrementCounterInBlock(entry, i, Counters); ++NumEdgesInserted;
- Initializer[i++] = (Zero);
- } else{
- Initializer[i++] = (Uncounted);
- }
-
- // InsertedBlocks contains all blocks that were inserted for splitting an
- // edge, this blocks do not have to be instrumented.
- DenseSet<BasicBlock*> InsertedBlocks;
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
- // Check if block was not inserted and thus does not have to be
- // instrumented.
- if (InsertedBlocks.count(BB)) continue;
-
- // Okay, we have to add a counter of each outgoing edge not in MST. If
- // the outgoing edge is not critical don't split it, just insert the
- // counter in the source or destination of the edge. Also, if the block
- // has no successors, the virtual edge (BB,0) is processed.
- TerminatorInst *TI = BB->getTerminator();
- if (TI->getNumSuccessors() == 0) {
- ProfileInfo::Edge edge = ProfileInfo::getEdge(BB, 0);
- if (!std::binary_search(MST.begin(), MST.end(), edge)) {
- printEdgeCounter(edge, BB, i);
- IncrementCounterInBlock(BB, i, Counters); ++NumEdgesInserted;
- Initializer[i++] = (Zero);
- } else{
- Initializer[i++] = (Uncounted);
- }
- }
- for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s) {
- BasicBlock *Succ = TI->getSuccessor(s);
- ProfileInfo::Edge edge = ProfileInfo::getEdge(BB,Succ);
- if (!std::binary_search(MST.begin(), MST.end(), edge)) {
-
- // If the edge is critical, split it.
- bool wasInserted = SplitCriticalEdge(TI, s, this);
- Succ = TI->getSuccessor(s);
- if (wasInserted)
- InsertedBlocks.insert(Succ);
-
- // Okay, we are guaranteed that the edge is no longer critical. If
- // we only have a single successor, insert the counter in this block,
- // otherwise insert it in the successor block.
- if (TI->getNumSuccessors() == 1) {
- // Insert counter at the start of the block
- printEdgeCounter(edge, BB, i);
- IncrementCounterInBlock(BB, i, Counters); ++NumEdgesInserted;
- } else {
- // Insert counter at the start of the block
- printEdgeCounter(edge, Succ, i);
- IncrementCounterInBlock(Succ, i, Counters); ++NumEdgesInserted;
- }
- Initializer[i++] = (Zero);
- } else {
- Initializer[i++] = (Uncounted);
- }
- }
- }
- }
-
- // Check if the number of edges counted at first was the number of edges we
- // considered for instrumentation.
- assert(i == NumEdges && "the number of edges in counting array is wrong");
-
- // Assign the now completely defined initialiser to the array.
- Constant *init = ConstantArray::get(ATy, Initializer);
- Counters->setInitializer(init);
-
- // Add the initialization call to main.
- InsertProfilingInitCall(Main, "llvm_start_opt_edge_profiling", Counters);
- return true;
-}
-