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
diff --git a/lib/Transforms/Instrumentation/CMakeLists.txt b/lib/Transforms/Instrumentation/CMakeLists.txt
index 83e12e1..be6a451 100644
--- a/lib/Transforms/Instrumentation/CMakeLists.txt
+++ b/lib/Transforms/Instrumentation/CMakeLists.txt
@@ -2,6 +2,7 @@
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 0000000..b6b996d
--- /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 <set>
+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<ProfileInfo>();
+ }
+
+ virtual const char *getPassName() const {
+ return "Optimal Edge Profiler";
+ }
+ };
+}
+
+char OptimalEdgeProfiler::ID = 0;
+static RegisterPass<OptimalEdgeProfiler>
+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<BasicBlock*> 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<Constant*> 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 "<<F->getNameStr()<<"\n");
+
+ PI = &getAnalysisID<ProfileInfo>(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;
+}
+