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-rw-r--r--lib/Analysis/ProfileVerifierPass.cpp343
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+//===- ProfileVerifierPass.cpp - LLVM Pass to estimate profile info -------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a pass that checks profiling information for
+// plausibility.
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "profile-verifier"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/ProfileInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Debug.h"
+#include <set>
+using namespace llvm;
+
+static cl::opt<bool,false>
+ProfileVerifierDisableAssertions("profile-verifier-noassert",
+ cl::desc("Disable assertions"));
+
+namespace {
+ class VISIBILITY_HIDDEN ProfileVerifierPass : public FunctionPass {
+
+ struct DetailedBlockInfo {
+ const BasicBlock *BB;
+ double BBWeight;
+ double inWeight;
+ int inCount;
+ double outWeight;
+ int outCount;
+ };
+
+ ProfileInfo *PI;
+ std::set<const BasicBlock*> BBisVisited;
+ std::set<const Function*> FisVisited;
+ bool DisableAssertions;
+
+ // When debugging is enabled, the verifier prints a whole slew of debug
+ // information, otherwise its just the assert. These are all the helper
+ // functions.
+ bool PrintedDebugTree;
+ std::set<const BasicBlock*> BBisPrinted;
+ void debugEntry(DetailedBlockInfo*);
+ void printDebugInfo(const BasicBlock *BB);
+
+ public:
+ static char ID; // Class identification, replacement for typeinfo
+
+ explicit ProfileVerifierPass () : FunctionPass(&ID) {
+ DisableAssertions = ProfileVerifierDisableAssertions;
+ }
+ explicit ProfileVerifierPass (bool da) : FunctionPass(&ID),
+ DisableAssertions(da) {
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<ProfileInfo>();
+ }
+
+ const char *getPassName() const {
+ return "Profiling information verifier";
+ }
+
+ /// run - Verify the profile information.
+ bool runOnFunction(Function &F);
+ void recurseBasicBlock(const BasicBlock*);
+
+ bool exitReachable(const Function*);
+ double ReadOrAssert(ProfileInfo::Edge);
+ void CheckValue(bool, const char*, DetailedBlockInfo*);
+ };
+} // End of anonymous namespace
+
+char ProfileVerifierPass::ID = 0;
+static RegisterPass<ProfileVerifierPass>
+X("profile-verifier", "Verify profiling information", false, true);
+
+namespace llvm {
+ FunctionPass *createProfileVerifierPass() {
+ return new ProfileVerifierPass(ProfileVerifierDisableAssertions);
+ }
+}
+
+void ProfileVerifierPass::printDebugInfo(const BasicBlock *BB) {
+
+ if (BBisPrinted.find(BB) != BBisPrinted.end()) return;
+
+ double BBWeight = PI->getExecutionCount(BB);
+ if (BBWeight == ProfileInfo::MissingValue) { BBWeight = 0; }
+ double inWeight = 0;
+ int inCount = 0;
+ std::set<const BasicBlock*> ProcessedPreds;
+ for ( pred_const_iterator bbi = pred_begin(BB), bbe = pred_end(BB);
+ bbi != bbe; ++bbi ) {
+ if (ProcessedPreds.insert(*bbi).second) {
+ ProfileInfo::Edge E = PI->getEdge(*bbi,BB);
+ double EdgeWeight = PI->getEdgeWeight(E);
+ if (EdgeWeight == ProfileInfo::MissingValue) { EdgeWeight = 0; }
+ errs() << "calculated in-edge " << E << ": " << EdgeWeight << "\n";
+ inWeight += EdgeWeight;
+ inCount++;
+ }
+ }
+ double outWeight = 0;
+ int outCount = 0;
+ std::set<const BasicBlock*> ProcessedSuccs;
+ for ( succ_const_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
+ bbi != bbe; ++bbi ) {
+ if (ProcessedSuccs.insert(*bbi).second) {
+ ProfileInfo::Edge E = PI->getEdge(BB,*bbi);
+ double EdgeWeight = PI->getEdgeWeight(E);
+ if (EdgeWeight == ProfileInfo::MissingValue) { EdgeWeight = 0; }
+ errs() << "calculated out-edge " << E << ": " << EdgeWeight << "\n";
+ outWeight += EdgeWeight;
+ outCount++;
+ }
+ }
+ errs()<<"Block "<<BB->getNameStr()<<" in "<<BB->getParent()->getNameStr()
+ <<",BBWeight="<<BBWeight<<",inWeight="<<inWeight<<",inCount="<<inCount
+ <<",outWeight="<<outWeight<<",outCount"<<outCount<<"\n";
+
+ // mark as visited and recurse into subnodes
+ BBisPrinted.insert(BB);
+ for ( succ_const_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
+ bbi != bbe; ++bbi ) {
+ printDebugInfo(*bbi);
+ }
+}
+
+void ProfileVerifierPass::debugEntry (DetailedBlockInfo *DI) {
+ errs() << "TROUBLE: Block " << DI->BB->getNameStr() << " in "
+ << DI->BB->getParent()->getNameStr() << ":";
+ errs() << "BBWeight=" << DI->BBWeight << ",";
+ errs() << "inWeight=" << DI->inWeight << ",";
+ errs() << "inCount=" << DI->inCount << ",";
+ errs() << "outWeight=" << DI->outWeight << ",";
+ errs() << "outCount=" << DI->outCount << "\n";
+ if (!PrintedDebugTree) {
+ PrintedDebugTree = true;
+ printDebugInfo(&(DI->BB->getParent()->getEntryBlock()));
+ }
+}
+
+// This compares A and B but considering maybe small differences.
+static bool Equals(double A, double B) {
+ double maxRelativeError = 0.0000001;
+ if (A == B)
+ return true;
+ double relativeError;
+ if (fabs(B) > fabs(A))
+ relativeError = fabs((A - B) / B);
+ else
+ relativeError = fabs((A - B) / A);
+ if (relativeError <= maxRelativeError) return true;
+ return false;
+}
+
+// This checks if the function "exit" is reachable from an given function
+// via calls, this is necessary to check if a profile is valid despite the
+// counts not fitting exactly.
+bool ProfileVerifierPass::exitReachable(const Function *F) {
+ if (!F) return false;
+
+ if (FisVisited.count(F)) return false;
+
+ Function *Exit = F->getParent()->getFunction("exit");
+ if (Exit == F) {
+ return true;
+ }
+
+ FisVisited.insert(F);
+ bool exits = false;
+ for (const_inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
+ if (const CallInst *CI = dyn_cast<CallInst>(&*I)) {
+ exits |= exitReachable(CI->getCalledFunction());
+ if (exits) break;
+ }
+ }
+ return exits;
+}
+
+#define ASSERTMESSAGE(M) \
+ errs() << (M) << "\n"; \
+ if (!DisableAssertions) assert(0 && (M));
+
+double ProfileVerifierPass::ReadOrAssert(ProfileInfo::Edge E) {
+ double EdgeWeight = PI->getEdgeWeight(E);
+ if (EdgeWeight == ProfileInfo::MissingValue) {
+ errs() << "Edge " << E << " in Function "
+ << ProfileInfo::getFunction(E)->getNameStr() << ": ";
+ ASSERTMESSAGE("ASSERT:Edge has missing value");
+ return 0;
+ } else {
+ return EdgeWeight;
+ }
+}
+
+void ProfileVerifierPass::CheckValue(bool Error, const char *Message,
+ DetailedBlockInfo *DI) {
+ if (Error) {
+ DEBUG(debugEntry(DI));
+ errs() << "Block " << DI->BB->getNameStr() << " in Function "
+ << DI->BB->getParent()->getNameStr() << ": ";
+ ASSERTMESSAGE(Message);
+ }
+ return;
+}
+
+// This calculates the Information for a block and then recurses into the
+// successors.
+void ProfileVerifierPass::recurseBasicBlock(const BasicBlock *BB) {
+
+ // Break the recursion by remembering all visited blocks.
+ if (BBisVisited.find(BB) != BBisVisited.end()) return;
+
+ // Use a data structure to store all the information, this can then be handed
+ // to debug printers.
+ DetailedBlockInfo DI;
+ DI.BB = BB;
+ DI.outCount = DI.inCount = DI.inWeight = DI.outWeight = 0;
+
+ // Read predecessors.
+ std::set<const BasicBlock*> ProcessedPreds;
+ pred_const_iterator bpi = pred_begin(BB), bpe = pred_end(BB);
+ // If there are none, check for (0,BB) edge.
+ if (bpi == bpe) {
+ DI.inWeight += ReadOrAssert(PI->getEdge(0,BB));
+ DI.inCount++;
+ }
+ for (;bpi != bpe; ++bpi) {
+ if (ProcessedPreds.insert(*bpi).second) {
+ DI.inWeight += ReadOrAssert(PI->getEdge(*bpi,BB));
+ DI.inCount++;
+ }
+ }
+
+ // Read successors.
+ std::set<const BasicBlock*> ProcessedSuccs;
+ succ_const_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
+ // If there is an (0,BB) edge, consider it too. (This is done not only when
+ // there are no successors, but every time; not every function contains
+ // return blocks with no successors (think loop latch as return block)).
+ double w = PI->getEdgeWeight(PI->getEdge(BB,0));
+ if (w != ProfileInfo::MissingValue) {
+ DI.outWeight += w;
+ DI.outCount++;
+ }
+ for (;bbi != bbe; ++bbi) {
+ if (ProcessedSuccs.insert(*bbi).second) {
+ DI.outWeight += ReadOrAssert(PI->getEdge(BB,*bbi));
+ DI.outCount++;
+ }
+ }
+
+ // Read block weight.
+ DI.BBWeight = PI->getExecutionCount(BB);
+ CheckValue(DI.BBWeight == ProfileInfo::MissingValue,
+ "ASSERT:BasicBlock has missing value", &DI);
+
+ // Check if this block is a setjmp target.
+ bool isSetJmpTarget = false;
+ if (DI.outWeight > DI.inWeight) {
+ for (BasicBlock::const_iterator i = BB->begin(), ie = BB->end();
+ i != ie; ++i) {
+ if (const CallInst *CI = dyn_cast<CallInst>(&*i)) {
+ Function *F = CI->getCalledFunction();
+ if (F && (F->getNameStr() == "_setjmp")) {
+ isSetJmpTarget = true; break;
+ }
+ }
+ }
+ }
+ // Check if this block is eventually reaching exit.
+ bool isExitReachable = false;
+ if (DI.inWeight > DI.outWeight) {
+ for (BasicBlock::const_iterator i = BB->begin(), ie = BB->end();
+ i != ie; ++i) {
+ if (const CallInst *CI = dyn_cast<CallInst>(&*i)) {
+ FisVisited.clear();
+ isExitReachable |= exitReachable(CI->getCalledFunction());
+ if (isExitReachable) break;
+ }
+ }
+ }
+
+ if (DI.inCount > 0 && DI.outCount == 0) {
+ // If this is a block with no successors.
+ if (!isSetJmpTarget) {
+ CheckValue(!Equals(DI.inWeight,DI.BBWeight),
+ "ASSERT:inWeight and BBWeight do not match", &DI);
+ }
+ } else if (DI.inCount == 0 && DI.outCount > 0) {
+ // If this is a block with no predecessors.
+ if (!isExitReachable)
+ CheckValue(!Equals(DI.BBWeight,DI.outWeight),
+ "ASSERT:BBWeight and outWeight do not match", &DI);
+ } else {
+ // If this block has successors and predecessors.
+ if (DI.inWeight > DI.outWeight && !isExitReachable)
+ CheckValue(!Equals(DI.inWeight,DI.outWeight),
+ "ASSERT:inWeight and outWeight do not match", &DI);
+ if (DI.inWeight < DI.outWeight && !isSetJmpTarget)
+ CheckValue(!Equals(DI.inWeight,DI.outWeight),
+ "ASSERT:inWeight and outWeight do not match", &DI);
+ }
+
+
+ // Mark this block as visited, rescurse into successors.
+ BBisVisited.insert(BB);
+ for ( succ_const_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
+ bbi != bbe; ++bbi ) {
+ recurseBasicBlock(*bbi);
+ }
+}
+
+bool ProfileVerifierPass::runOnFunction(Function &F) {
+ PI = &getAnalysis<ProfileInfo>();
+
+ // Prepare global variables.
+ PrintedDebugTree = false;
+ BBisVisited.clear();
+
+ // Fetch entry block and recurse into it.
+ const BasicBlock *entry = &F.getEntryBlock();
+ recurseBasicBlock(entry);
+
+ if (!DisableAssertions)
+ assert((PI->getExecutionCount(&F)==PI->getExecutionCount(entry)) &&
+ "Function count and entry block count do not match");
+ return false;
+}
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