//===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasAnalysisEvaluator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
static cl::opt<bool> PrintMust("print-must", cl::ReallyHidden);
static cl::opt<bool> PrintMustRef("print-mustref", cl::ReallyHidden);
static cl::opt<bool> PrintMustMod("print-mustmod", cl::ReallyHidden);
static cl::opt<bool> PrintMustModRef("print-mustmodref", cl::ReallyHidden);
static cl::opt<bool> EvalAAMD("evaluate-aa-metadata", cl::ReallyHidden);
static void PrintResults(AliasResult AR, bool P, const Value *V1,
const Value *V2, const Module *M) {
if (PrintAll || P) {
std::string o1, o2;
{
raw_string_ostream os1(o1), os2(o2);
V1->printAsOperand(os1, true, M);
V2->printAsOperand(os2, true, M);
}
if (o2 < o1)
std::swap(o1, o2);
errs() << " " << AR << ":\t" << o1 << ", " << o2 << "\n";
}
}
static inline void PrintModRefResults(const char *Msg, bool P, Instruction *I,
Value *Ptr, Module *M) {
if (PrintAll || P) {
errs() << " " << Msg << ": Ptr: ";
Ptr->printAsOperand(errs(), true, M);
errs() << "\t<->" << *I << '\n';
}
}
static inline void PrintModRefResults(const char *Msg, bool P, CallBase *CallA,
CallBase *CallB, Module *M) {
if (PrintAll || P) {
errs() << " " << Msg << ": " << *CallA << " <-> " << *CallB << '\n';
}
}
static inline void PrintLoadStoreResults(AliasResult AR, bool P,
const Value *V1, const Value *V2,
const Module *M) {
if (PrintAll || P) {
errs() << " " << AR << ": " << *V1 << " <-> " << *V2 << '\n';
}
}
static inline bool isInterestingPointer(Value *V) {
return V->getType()->isPointerTy()
&& !isa<ConstantPointerNull>(V);
}
PreservedAnalyses AAEvaluator::run(Function &F, FunctionAnalysisManager &AM) {
runInternal(F, AM.getResult<AAManager>(F));
return PreservedAnalyses::all();
}
void AAEvaluator::runInternal(Function &F, AAResults &AA) {
const DataLayout &DL = F.getParent()->getDataLayout();
++FunctionCount;
SetVector<Value *> Pointers;
SmallSetVector<CallBase *, 16> Calls;
SetVector<Value *> Loads;
SetVector<Value *> Stores;
for (auto &I : F.args())
if (I.getType()->isPointerTy()) // Add all pointer arguments.
Pointers.insert(&I);
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
if (I->getType()->isPointerTy()) // Add all pointer instructions.
Pointers.insert(&*I);
if (EvalAAMD && isa<LoadInst>(&*I))
Loads.insert(&*I);
if (EvalAAMD && isa<StoreInst>(&*I))
Stores.insert(&*I);
Instruction &Inst = *I;
if (auto *Call = dyn_cast<CallBase>(&Inst)) {
Value *Callee = Call->getCalledOperand();
// Skip actual functions for direct function calls.
if (!isa<Function>(Callee) && isInterestingPointer(Callee))
Pointers.insert(Callee);
// Consider formals.
for (Use &DataOp : Call->data_ops())
if (isInterestingPointer(DataOp))
Pointers.insert(DataOp);
Calls.insert(Call);
} else {
// Consider all operands.
for (Instruction::op_iterator OI = Inst.op_begin(), OE = Inst.op_end();
OI != OE; ++OI)
if (isInterestingPointer(*OI))
Pointers.insert(*OI);
}
}
if (PrintAll || PrintNoAlias || PrintMayAlias || PrintPartialAlias ||
PrintMustAlias || PrintNoModRef || PrintMod || PrintRef || PrintModRef)
errs() << "Function: " << F.getName() << ": " << Pointers.size()
<< " pointers, " << Calls.size() << " call sites\n";
// iterate over the worklist, and run the full (n^2)/2 disambiguations
for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
I1 != E; ++I1) {
auto I1Size = LocationSize::afterPointer();
Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
if (I1ElTy->isSized())
I1Size = LocationSize::precise(DL.getTypeStoreSize(I1ElTy));
for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
auto I2Size = LocationSize::afterPointer();
Type *I2ElTy = cast<PointerType>((*I2)->getType())->getElementType();
if (I2ElTy->isSized())
I2Size = LocationSize::precise(DL.getTypeStoreSize(I2ElTy));
AliasResult AR = AA.alias(*I1, I1Size, *I2, I2Size);
switch (AR) {
case NoAlias:
PrintResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
++NoAliasCount;
break;
case MayAlias:
PrintResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
++MayAliasCount;
break;
case PartialAlias:
PrintResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
++PartialAliasCount;
break;
case MustAlias:
PrintResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
++MustAliasCount;
break;
}
}
}
if (EvalAAMD) {
// iterate over all pairs of load, store
for (Value *Load : Loads) {
for (Value *Store : Stores) {
AliasResult AR = AA.alias(MemoryLocation::get(cast<LoadInst>(Load)),
MemoryLocation::get(cast<StoreInst>(Store)));
switch (AR) {
case NoAlias:
PrintLoadStoreResults(AR, PrintNoAlias, Load, Store, F.getParent());
++NoAliasCount;
break;
case MayAlias:
PrintLoadStoreResults(AR, PrintMayAlias, Load, Store, F.getParent());
++MayAliasCount;
break;
case PartialAlias:
PrintLoadStoreResults(AR, PrintPartialAlias, Load, Store, F.getParent());
++PartialAliasCount;
break;
case MustAlias:
PrintLoadStoreResults(AR, PrintMustAlias, Load, Store, F.getParent());
++MustAliasCount;
break;
}
}
}
// iterate over all pairs of store, store
for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
I1 != E; ++I1) {
for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
AliasResult AR = AA.alias(MemoryLocation::get(cast<StoreInst>(*I1)),
MemoryLocation::get(cast<StoreInst>(*I2)));
switch (AR) {
case NoAlias:
PrintLoadStoreResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
++NoAliasCount;
break;
case MayAlias:
PrintLoadStoreResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
++MayAliasCount;
break;
case PartialAlias:
PrintLoadStoreResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
++PartialAliasCount;
break;
case MustAlias:
PrintLoadStoreResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
++MustAliasCount;
break;
}
}
}
}
// Mod/ref alias analysis: compare all pairs of calls and values
for (CallBase *Call : Calls) {
for (auto Pointer : Pointers) {
auto Size = LocationSize::afterPointer();
Type *ElTy = cast<PointerType>(Pointer->getType())->getElementType();
if (ElTy->isSized())
Size = LocationSize::precise(DL.getTypeStoreSize(ElTy));
switch (AA.getModRefInfo(Call, Pointer, Size)) {
case ModRefInfo::NoModRef:
PrintModRefResults("NoModRef", PrintNoModRef, Call, Pointer,
F.getParent());
++NoModRefCount;
break;
case ModRefInfo::Mod:
PrintModRefResults("Just Mod", PrintMod, Call, Pointer, F.getParent());
++ModCount;
break;
case ModRefInfo::Ref:
PrintModRefResults("Just Ref", PrintRef, Call, Pointer, F.getParent());
++RefCount;
break;
case ModRefInfo::ModRef:
PrintModRefResults("Both ModRef", PrintModRef, Call, Pointer,
F.getParent());
++ModRefCount;
break;
case ModRefInfo::Must:
PrintModRefResults("Must", PrintMust, Call, Pointer, F.getParent());
++MustCount;
break;
case ModRefInfo::MustMod:
PrintModRefResults("Just Mod (MustAlias)", PrintMustMod, Call, Pointer,
F.getParent());
++MustModCount;
break;
case ModRefInfo::MustRef:
PrintModRefResults("Just Ref (MustAlias)", PrintMustRef, Call, Pointer,
F.getParent());
++MustRefCount;
break;
case ModRefInfo::MustModRef:
PrintModRefResults("Both ModRef (MustAlias)", PrintMustModRef, Call,
Pointer, F.getParent());
++MustModRefCount;
break;
}
}
}
// Mod/ref alias analysis: compare all pairs of calls
for (CallBase *CallA : Calls) {
for (CallBase *CallB : Calls) {
if (CallA == CallB)
continue;
switch (AA.getModRefInfo(CallA, CallB)) {
case ModRefInfo::NoModRef:
PrintModRefResults("NoModRef", PrintNoModRef, CallA, CallB,
F.getParent());
++NoModRefCount;
break;
case ModRefInfo::Mod:
PrintModRefResults("Just Mod", PrintMod, CallA, CallB, F.getParent());
++ModCount;
break;
case ModRefInfo::Ref:
PrintModRefResults("Just Ref", PrintRef, CallA, CallB, F.getParent());
++RefCount;
break;
case ModRefInfo::ModRef:
PrintModRefResults("Both ModRef", PrintModRef, CallA, CallB,
F.getParent());
++ModRefCount;
break;
case ModRefInfo::Must:
PrintModRefResults("Must", PrintMust, CallA, CallB, F.getParent());
++MustCount;
break;
case ModRefInfo::MustMod:
PrintModRefResults("Just Mod (MustAlias)", PrintMustMod, CallA, CallB,
F.getParent());
++MustModCount;
break;
case ModRefInfo::MustRef:
PrintModRefResults("Just Ref (MustAlias)", PrintMustRef, CallA, CallB,
F.getParent());
++MustRefCount;
break;
case ModRefInfo::MustModRef:
PrintModRefResults("Both ModRef (MustAlias)", PrintMustModRef, CallA,
CallB, F.getParent());
++MustModRefCount;
break;
}
}
}
}
static void PrintPercent(int64_t Num, int64_t Sum) {
errs() << "(" << Num * 100LL / Sum << "." << ((Num * 1000LL / Sum) % 10)
<< "%)\n";
}
AAEvaluator::~AAEvaluator() {
if (FunctionCount == 0)
return;
int64_t AliasSum =
NoAliasCount + MayAliasCount + PartialAliasCount + MustAliasCount;
errs() << "===== Alias Analysis Evaluator Report =====\n";
if (AliasSum == 0) {
errs() << " Alias Analysis Evaluator Summary: No pointers!\n";
} else {
errs() << " " << AliasSum << " Total Alias Queries Performed\n";
errs() << " " << NoAliasCount << " no alias responses ";
PrintPercent(NoAliasCount, AliasSum);
errs() << " " << MayAliasCount << " may alias responses ";
PrintPercent(MayAliasCount, AliasSum);
errs() << " " << PartialAliasCount << " partial alias responses ";
PrintPercent(PartialAliasCount, AliasSum);
errs() << " " << MustAliasCount << " must alias responses ";
PrintPercent(MustAliasCount, AliasSum);
errs() << " Alias Analysis Evaluator Pointer Alias Summary: "
<< NoAliasCount * 100 / AliasSum << "%/"
<< MayAliasCount * 100 / AliasSum << "%/"
<< PartialAliasCount * 100 / AliasSum << "%/"
<< MustAliasCount * 100 / AliasSum << "%\n";
}
// Display the summary for mod/ref analysis
int64_t ModRefSum = NoModRefCount + RefCount + ModCount + ModRefCount +
MustCount + MustRefCount + MustModCount + MustModRefCount;
if (ModRefSum == 0) {
errs() << " Alias Analysis Mod/Ref Evaluator Summary: no "
"mod/ref!\n";
} else {
errs() << " " << ModRefSum << " Total ModRef Queries Performed\n";
errs() << " " << NoModRefCount << " no mod/ref responses ";
PrintPercent(NoModRefCount, ModRefSum);
errs() << " " << ModCount << " mod responses ";
PrintPercent(ModCount, ModRefSum);
errs() << " " << RefCount << " ref responses ";
PrintPercent(RefCount, ModRefSum);
errs() << " " << ModRefCount << " mod & ref responses ";
PrintPercent(ModRefCount, ModRefSum);
errs() << " " << MustCount << " must responses ";
PrintPercent(MustCount, ModRefSum);
errs() << " " << MustModCount << " must mod responses ";
PrintPercent(MustModCount, ModRefSum);
errs() << " " << MustRefCount << " must ref responses ";
PrintPercent(MustRefCount, ModRefSum);
errs() << " " << MustModRefCount << " must mod & ref responses ";
PrintPercent(MustModRefCount, ModRefSum);
errs() << " Alias Analysis Evaluator Mod/Ref Summary: "
<< NoModRefCount * 100 / ModRefSum << "%/"
<< ModCount * 100 / ModRefSum << "%/" << RefCount * 100 / ModRefSum
<< "%/" << ModRefCount * 100 / ModRefSum << "%/"
<< MustCount * 100 / ModRefSum << "%/"
<< MustRefCount * 100 / ModRefSum << "%/"
<< MustModCount * 100 / ModRefSum << "%/"
<< MustModRefCount * 100 / ModRefSum << "%\n";
}
}
namespace llvm {
class AAEvalLegacyPass : public FunctionPass {
std::unique_ptr<AAEvaluator> P;
public:
static char ID; // Pass identification, replacement for typeid
AAEvalLegacyPass() : FunctionPass(ID) {
initializeAAEvalLegacyPassPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AAResultsWrapperPass>();
AU.setPreservesAll();
}
bool doInitialization(Module &M) override {
P.reset(new AAEvaluator());
return false;
}
bool runOnFunction(Function &F) override {
P->runInternal(F, getAnalysis<AAResultsWrapperPass>().getAAResults());
return false;
}
bool doFinalization(Module &M) override {
P.reset();
return false;
}
};
}
char AAEvalLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(AAEvalLegacyPass, "aa-eval",
"Exhaustive Alias Analysis Precision Evaluator", false,
true)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_END(AAEvalLegacyPass, "aa-eval",
"Exhaustive Alias Analysis Precision Evaluator", false,
true)
FunctionPass *llvm::createAAEvalPass() { return new AAEvalLegacyPass(); }
