From f771dae69aee00a16dbfb7e712bf26ab2b9d9cde Mon Sep 17 00:00:00 2001 From: Andreas Neustifter Date: Tue, 1 Sep 2009 19:03:44 +0000 Subject: OptimalEdgeProfiling: Creation of profiles. This adds the instrumentation and runtime part of OptimalEdgeProfiling. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80712 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Instrumentation/CMakeLists.txt | 1 + .../Instrumentation/OptimalEdgeProfiling.cpp | 186 +++++++++++++++++++++ 2 files changed, 187 insertions(+) create mode 100644 lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp (limited to 'lib/Transforms') diff --git a/lib/Transforms/Instrumentation/CMakeLists.txt b/lib/Transforms/Instrumentation/CMakeLists.txt index 83e12e12d8..be6a451f57 100644 --- a/lib/Transforms/Instrumentation/CMakeLists.txt +++ b/lib/Transforms/Instrumentation/CMakeLists.txt @@ -2,6 +2,7 @@ add_llvm_library(LLVMInstrumentation BlockProfiling.cpp EdgeProfiling.cpp MaximumSpanningTree.cpp + OptimalEdgeProfiling.cpp ProfilingUtils.cpp RSProfiling.cpp ) diff --git a/lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp b/lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp new file mode 100644 index 0000000000..b6b996d7a3 --- /dev/null +++ b/lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp @@ -0,0 +1,186 @@ +//===- 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 "ProfilingUtils.h" +#include "llvm/Constants.h" +#include "llvm/Function.h" +#include "llvm/LLVMContext.h" +#include "llvm/Module.h" +#include "llvm/Pass.h" +#include "llvm/Analysis/Passes.h" +#include "llvm/Analysis/ProfileInfo.h" +#include "llvm/Support/Compiler.h" +#include "llvm/Support/Debug.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Transforms/Instrumentation.h" +#include "llvm/ADT/Statistic.h" +#include "MaximumSpanningTree.h" +#include +using namespace llvm; + +STATISTIC(NumEdgesInserted, "The # of edges inserted."); + +namespace { + class VISIBILITY_HIDDEN OptimalEdgeProfiler : public ModulePass { + bool runOnModule(Module &M); + ProfileInfo *PI; + public: + static char ID; // Pass identification, replacement for typeid + OptimalEdgeProfiler() : ModulePass(&ID) {} + + void getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequiredID(ProfileEstimatorPassID); + AU.addRequired(); + } + + virtual const char *getPassName() const { + return "Optimal Edge Profiler"; + } + }; +} + +char OptimalEdgeProfiler::ID = 0; +static RegisterPass +X("insert-optimal-edge-profiling", + "Insert optimal instrumentation for edge profiling"); + +ModulePass *llvm::createOptimalEdgeProfilerPass() { + return new OptimalEdgeProfiler(); +} + +inline static void printEdgeCounter(ProfileInfo::Edge e, + BasicBlock* b, + unsigned i) { + DEBUG(errs() << "--Edge Counter for " << (e) << " in " \ + << ((b)?(b)->getNameStr():"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! + } + + std::set BlocksToInstrument; + 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! + BlocksToInstrument.insert(BB); + if (BB->getTerminator()->getNumSuccessors() == 0) { + // Reserve space for (BB,0) edge. + ++NumEdges; + } else { + NumEdges += BB->getTerminator()->getNumSuccessors(); + } + } + } + + const Type *Int32 = Type::getInt32Ty(M.getContext()); + const ArrayType *ATy = ArrayType::get(Int32, NumEdges); + GlobalVariable *Counters = + new GlobalVariable(M, ATy, false, GlobalValue::InternalLinkage, + Constant::getNullValue(ATy), "OptEdgeProfCounters"); + NumEdgesInserted = 0; + + std::vector Initializer(NumEdges); + Constant* zeroc = ConstantInt::get(Int32, 0); + Constant* minusonec = ConstantInt::get(Int32, ProfileInfo::MissingValue); + + // 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(errs()<<"Working on "<getNameStr()<<"\n"); + + PI = &getAnalysisID(ProfileEstimatorPassID,*F); + MaximumSpanningTree MST = MaximumSpanningTree(&(*F),PI,true); + + // Create counter for (0,entry) edge. + 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++] = (zeroc); + } else{ + Initializer[i++] = (minusonec); + } + + for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { + if (!BlocksToInstrument.count(BB)) continue; // Don't count new blocks + // 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. + TerminatorInst *TI = BB->getTerminator(); + if (TI->getNumSuccessors() == 0) { + // Create counter for (BB,0), edge. + 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++] = (zeroc); + } else{ + Initializer[i++] = (minusonec); + } + } + 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. + SplitCriticalEdge(TI,s,this); + Succ = TI->getSuccessor(s); + + // 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++] = (zeroc); + } else { + Initializer[i++] = (minusonec); + } + } + } + } + + // check if indeed all counters have been used + assert(i==NumEdges && "the number of edges in counting array is wrong"); + + // assign initialiser to 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; +} + -- cgit v1.2.3