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

188 lines
7.1 KiB
C++
Raw Normal View History

//===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a simple N^2 alias analysis accuracy evaluator.
// Basically, for each function in the program, it simply queries to see how the
// alias analysis implementation answers alias queries between each pair of
// pointers in the function.
//
// This is inspired and adapted from code by: Naveen Neelakantam, Francesco
// Spadini, and Wojciech Stryjewski.
//
//===----------------------------------------------------------------------===//
#include "llvm/Function.h"
#include "llvm/iOther.h"
#include "llvm/iTerminators.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/InstIterator.h"
#include "Support/CommandLine.h"
#include <set>
using namespace llvm;
namespace {
cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
class AAEval : public FunctionPass {
unsigned NoAlias, MayAlias, MustAlias;
unsigned NoModRef, Mod, Ref, ModRef;
public:
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<AliasAnalysis>();
AU.setPreservesAll();
}
bool doInitialization(Module &M) {
NoAlias = MayAlias = MustAlias = 0;
NoModRef = Mod = Ref = ModRef = 0;
return false;
}
bool runOnFunction(Function &F);
bool doFinalization(Module &M);
};
RegisterOpt<AAEval>
X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
}
static inline void PrintResults(const char *Msg, bool P, Value *V1, Value *V2,
Module *M) {
if (P) {
std::cerr << " " << Msg << ":\t";
WriteAsOperand(std::cerr, V1, true, true, M) << ", ";
WriteAsOperand(std::cerr, V2, true, true, M) << "\n";
}
}
bool AAEval::runOnFunction(Function &F) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
std::set<Value *> Pointers;
std::set<CallSite> CallSites;
for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
if (isa<PointerType>(I->getType())) // Add all pointer arguments
Pointers.insert(I);
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
if (isa<PointerType>((*I)->getType())) // Add all pointer instructions
Pointers.insert(*I);
for (User::op_iterator OI = (*I)->op_begin(); OI != (*I)->op_end(); ++OI)
if (isa<PointerType>((*OI)->getType()))
Pointers.insert(*OI);
}
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
if (CallInst *CI = dyn_cast<CallInst>(*I))
CallSites.insert(CallSite(CI));
else if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
CallSites.insert(CallSite(II));
}
if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
PrintNoModRef || PrintMod || PrintRef || PrintModRef)
std::cerr << "Function: " << F.getName() << "\n";
// iterate over the worklist, and run the full (n^2)/2 disambiguations
for (std::set<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
I1 != E; ++I1)
for (std::set<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2)
switch (AA.alias(*I1, 0, *I2, 0)) {
case AliasAnalysis::NoAlias:
PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
++NoAlias; break;
case AliasAnalysis::MayAlias:
PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
++MayAlias; break;
case AliasAnalysis::MustAlias:
PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
++MustAlias; break;
default:
std::cerr << "Unknown alias query result!\n";
}
// Mod/ref alias analysis: compare all pairs of calls and values
for (std::set<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
V != Ve; ++V)
for (std::set<CallSite>::iterator C = CallSites.begin(),
Ce = CallSites.end(); C != Ce; ++C) {
Instruction *I = C->getInstruction();
switch (AA.getModRefInfo(*C, *V, (*V)->getType()->getPrimitiveSize())) {
case AliasAnalysis::NoModRef:
PrintResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
++NoModRef; break;
case AliasAnalysis::Mod:
PrintResults("Mod", PrintMod, I, *V, F.getParent());
++Mod; break;
case AliasAnalysis::Ref:
PrintResults("Ref", PrintRef, I, *V, F.getParent());
++Ref; break;
case AliasAnalysis::ModRef:
PrintResults("ModRef", PrintModRef, I, *V, F.getParent());
++ModRef; break;
default:
std::cerr << "Unknown alias query result!\n";
}
}
return false;
}
bool AAEval::doFinalization(Module &M) {
unsigned AliasSum = NoAlias + MayAlias + MustAlias;
std::cerr << "===== Alias Analysis Evaluator Report =====\n";
if (AliasSum == 0) {
std::cerr << " Alias Analysis Evaluator Summary: No pointers!\n";
} else {
std::cerr << " " << AliasSum << " Total Alias Queries Performed\n";
std::cerr << " " << NoAlias << " no alias responses ("
<< NoAlias*100/AliasSum << "%)\n";
std::cerr << " " << MayAlias << " may alias responses ("
<< MayAlias*100/AliasSum << "%)\n";
std::cerr << " " << MustAlias << " must alias responses ("
<< MustAlias*100/AliasSum <<"%)\n";
std::cerr << " Alias Analysis Evaluator Pointer Alias Summary: "
<< NoAlias*100/AliasSum << "%/" << MayAlias*100/AliasSum << "%/"
<< MustAlias*100/AliasSum << "%\n";
}
// Display the summary for mod/ref analysis
unsigned ModRefSum = NoModRef + Mod + Ref + ModRef;
if (ModRefSum == 0) {
std::cerr << " Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!\n";
} else {
std::cerr << " " << ModRefSum << " Total ModRef Queries Performed\n";
std::cerr << " " << NoModRef << " no mod/ref responses ("
<< NoModRef*100/ModRefSum << "%)\n";
std::cerr << " " << Mod << " mod responses ("
<< Mod*100/ModRefSum << "%)\n";
std::cerr << " " << Ref << " ref responses ("
<< Ref*100/ModRefSum <<"%)\n";
std::cerr << " " << ModRef << " mod & ref responses ("
<< ModRef*100/ModRefSum <<"%)\n";
std::cerr << " Alias Analysis Evaluator Mod/Ref Summary: "
<< NoModRef*100/ModRefSum << "%/" << Mod*100/ModRefSum << "%/"
<< Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";
}
return false;
}