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llvm-project/llvm/lib/Analysis/ProfileVerifierPass.cpp

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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/Format.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 {
template<class FType, class BType>
class ProfileVerifierPassT : public FunctionPass {
struct DetailedBlockInfo {
const BType *BB;
double BBWeight;
double inWeight;
int inCount;
double outWeight;
int outCount;
};
ProfileInfoT<FType, BType> *PI;
std::set<const BType*> BBisVisited;
std::set<const FType*> 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 BType*> BBisPrinted;
void debugEntry(DetailedBlockInfo*);
void printDebugInfo(const BType *BB);
public:
static char ID; // Class identification, replacement for typeinfo
explicit ProfileVerifierPassT () : FunctionPass(ID) {
initializeProfileVerifierPassPass(*PassRegistry::getPassRegistry());
DisableAssertions = ProfileVerifierDisableAssertions;
}
explicit ProfileVerifierPassT (bool da) : FunctionPass(ID),
DisableAssertions(da) {
initializeProfileVerifierPassPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<ProfileInfoT<FType, BType> >();
}
const char *getPassName() const {
return "Profiling information verifier";
}
/// run - Verify the profile information.
bool runOnFunction(FType &F);
void recurseBasicBlock(const BType*);
bool exitReachable(const FType*);
double ReadOrAssert(typename ProfileInfoT<FType, BType>::Edge);
void CheckValue(bool, const char*, DetailedBlockInfo*);
};
typedef ProfileVerifierPassT<Function, BasicBlock> ProfileVerifierPass;
template<class FType, class BType>
void ProfileVerifierPassT<FType, BType>::printDebugInfo(const BType *BB) {
if (BBisPrinted.find(BB) != BBisPrinted.end()) return;
double BBWeight = PI->getExecutionCount(BB);
if (BBWeight == ProfileInfoT<FType, BType>::MissingValue) { BBWeight = 0; }
double inWeight = 0;
int inCount = 0;
std::set<const BType*> ProcessedPreds;
for (const_pred_iterator bbi = pred_begin(BB), bbe = pred_end(BB);
bbi != bbe; ++bbi ) {
if (ProcessedPreds.insert(*bbi).second) {
typename ProfileInfoT<FType, BType>::Edge E = PI->getEdge(*bbi,BB);
double EdgeWeight = PI->getEdgeWeight(E);
if (EdgeWeight == ProfileInfoT<FType, BType>::MissingValue) { EdgeWeight = 0; }
dbgs() << "calculated in-edge " << E << ": "
<< format("%20.20g",EdgeWeight) << "\n";
inWeight += EdgeWeight;
inCount++;
}
}
double outWeight = 0;
int outCount = 0;
std::set<const BType*> ProcessedSuccs;
for ( succ_const_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
bbi != bbe; ++bbi ) {
if (ProcessedSuccs.insert(*bbi).second) {
typename ProfileInfoT<FType, BType>::Edge E = PI->getEdge(BB,*bbi);
double EdgeWeight = PI->getEdgeWeight(E);
if (EdgeWeight == ProfileInfoT<FType, BType>::MissingValue) { EdgeWeight = 0; }
dbgs() << "calculated out-edge " << E << ": "
<< format("%20.20g",EdgeWeight) << "\n";
outWeight += EdgeWeight;
outCount++;
}
}
dbgs() << "Block " << BB->getName() << " in "
<< BB->getParent()->getName() << ":"
<< "BBWeight=" << format("%20.20g",BBWeight) << ","
<< "inWeight=" << format("%20.20g",inWeight) << ","
<< "inCount=" << inCount << ","
<< "outWeight=" << format("%20.20g",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);
}
}
template<class FType, class BType>
void ProfileVerifierPassT<FType, BType>::debugEntry (DetailedBlockInfo *DI) {
dbgs() << "TROUBLE: Block " << DI->BB->getName() << " in "
<< DI->BB->getParent()->getName() << ":"
<< "BBWeight=" << format("%20.20g",DI->BBWeight) << ","
<< "inWeight=" << format("%20.20g",DI->inWeight) << ","
<< "inCount=" << DI->inCount << ","
<< "outWeight=" << format("%20.20g",DI->outWeight) << ","
<< "outCount=" << DI->outCount << "\n";
if (!PrintedDebugTree) {
PrintedDebugTree = true;
printDebugInfo(&(DI->BB->getParent()->getEntryBlock()));
}
}
// This compares A and B for equality.
static bool Equals(double A, double B) {
return A == B;
}
// 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.
template<class FType, class BType>
bool ProfileVerifierPassT<FType, BType>::exitReachable(const FType *F) {
if (!F) return false;
if (FisVisited.count(F)) return false;
FType *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)) {
FType *F = CI->getCalledFunction();
if (F) {
exits |= exitReachable(F);
} else {
// This is a call to a pointer, all bets are off...
exits = true;
}
if (exits) break;
}
}
return exits;
}
#define ASSERTMESSAGE(M) \
{ dbgs() << "ASSERT:" << (M) << "\n"; \
if (!DisableAssertions) assert(0 && (M)); }
template<class FType, class BType>
double ProfileVerifierPassT<FType, BType>::ReadOrAssert(typename ProfileInfoT<FType, BType>::Edge E) {
double EdgeWeight = PI->getEdgeWeight(E);
if (EdgeWeight == ProfileInfoT<FType, BType>::MissingValue) {
dbgs() << "Edge " << E << " in Function "
<< ProfileInfoT<FType, BType>::getFunction(E)->getName() << ": ";
ASSERTMESSAGE("Edge has missing value");
return 0;
} else {
if (EdgeWeight < 0) {
dbgs() << "Edge " << E << " in Function "
<< ProfileInfoT<FType, BType>::getFunction(E)->getName() << ": ";
ASSERTMESSAGE("Edge has negative value");
}
return EdgeWeight;
}
}
template<class FType, class BType>
void ProfileVerifierPassT<FType, BType>::CheckValue(bool Error,
const char *Message,
DetailedBlockInfo *DI) {
if (Error) {
DEBUG(debugEntry(DI));
dbgs() << "Block " << DI->BB->getName() << " in Function "
<< DI->BB->getParent()->getName() << ": ";
ASSERTMESSAGE(Message);
}
return;
}
// This calculates the Information for a block and then recurses into the
// successors.
template<class FType, class BType>
void ProfileVerifierPassT<FType, BType>::recurseBasicBlock(const BType *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 = 0;
DI.inWeight = DI.outWeight = 0;
// Read predecessors.
std::set<const BType*> ProcessedPreds;
const_pred_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 BType*> 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 != ProfileInfoT<FType, BType>::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 == ProfileInfoT<FType, BType>::MissingValue,
"BasicBlock has missing value", &DI);
CheckValue(DI.BBWeight < 0,
"BasicBlock has negative value", &DI);
// Check if this block is a setjmp target.
bool isSetJmpTarget = false;
if (DI.outWeight > DI.inWeight) {
for (typename BType::const_iterator i = BB->begin(), ie = BB->end();
i != ie; ++i) {
if (const CallInst *CI = dyn_cast<CallInst>(&*i)) {
FType *F = CI->getCalledFunction();
if (F && (F->getName() == "_setjmp")) {
isSetJmpTarget = true; break;
}
}
}
}
// Check if this block is eventually reaching exit.
bool isExitReachable = false;
if (DI.inWeight > DI.outWeight) {
for (typename BType::const_iterator i = BB->begin(), ie = BB->end();
i != ie; ++i) {
if (const CallInst *CI = dyn_cast<CallInst>(&*i)) {
FType *F = CI->getCalledFunction();
if (F) {
FisVisited.clear();
isExitReachable |= exitReachable(F);
} else {
// This is a call to a pointer, all bets are off...
isExitReachable = true;
}
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),
"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),
"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),
"inWeight and outWeight do not match", &DI);
if (DI.inWeight < DI.outWeight && !isSetJmpTarget)
CheckValue(!Equals(DI.inWeight,DI.outWeight),
"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);
}
}
template<class FType, class BType>
bool ProfileVerifierPassT<FType, BType>::runOnFunction(FType &F) {
PI = getAnalysisIfAvailable<ProfileInfoT<FType, BType> >();
if (!PI)
ASSERTMESSAGE("No ProfileInfo available");
// Prepare global variables.
PrintedDebugTree = false;
BBisVisited.clear();
// Fetch entry block and recurse into it.
const BType *entry = &F.getEntryBlock();
recurseBasicBlock(entry);
if (PI->getExecutionCount(&F) != PI->getExecutionCount(entry))
ASSERTMESSAGE("Function count and entry block count do not match");
return false;
}
template<class FType, class BType>
char ProfileVerifierPassT<FType, BType>::ID = 0;
}
INITIALIZE_PASS_BEGIN(ProfileVerifierPass, "profile-verifier",
"Verify profiling information", false, true)
INITIALIZE_AG_DEPENDENCY(ProfileInfo)
INITIALIZE_PASS_END(ProfileVerifierPass, "profile-verifier",
"Verify profiling information", false, true)
namespace llvm {
FunctionPass *createProfileVerifierPass() {
return new ProfileVerifierPass(ProfileVerifierDisableAssertions);
}
}
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