1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
3 // This file implements a simple N^2 alias analysis accuracy evaluator.
4 // Basically, for each function in the program, it simply queries to see how the
5 // alias analysis implementation answers alias queries between each pair of
6 // pointers in the function.
8 // This is inspired and adapted from code by: Naveen Neelakantam, Francesco
9 // Spadini, and Wojciech Stryjewski.
11 //===----------------------------------------------------------------------===//
13 #include "llvm/Analysis/AliasAnalysis.h"
14 #include "llvm/Pass.h"
15 #include "llvm/Function.h"
16 #include "llvm/Support/InstIterator.h"
17 #include "llvm/Type.h"
20 class AAEval : public FunctionPass {
21 unsigned No, May, Must;
24 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
25 AU.addRequired<AliasAnalysis>();
29 bool doInitialization(Module &M) { No = May = Must = 0; return false; }
30 bool runOnFunction(Function &F);
31 bool doFinalization(Module &M);
35 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
38 bool AAEval::runOnFunction(Function &F) {
39 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
41 std::vector<Value *> Pointers;
43 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
44 if (isa<PointerType>(I->getType())) // Add all pointer arguments
45 Pointers.push_back(I);
47 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
48 if (isa<PointerType>((*I)->getType())) // Add all pointer instructions
49 Pointers.push_back(*I);
51 // iterate over the worklist, and run the full (n^2)/2 disambiguations
52 for (std::vector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
54 for (std::vector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2)
55 switch (AA.alias(*I1, *I2)) {
56 case AliasAnalysis::NoAlias: ++No; break;
57 case AliasAnalysis::MayAlias: ++May; break;
58 case AliasAnalysis::MustAlias: ++Must; break;
60 std::cerr << "Unknown alias query result!\n";
66 bool AAEval::doFinalization(Module &M) {
67 unsigned Sum = No+May+Must;
68 std::cerr << "===== Alias Analysis Evaluator Report =====\n";
69 std::cerr << " " << Sum << " Total Alias Queries Performed\n";
70 std::cerr << " " << No << " no alias responses (" << No*100/Sum << "%)\n";
71 std::cerr << " " << May << " may alias responses (" << May*100/Sum << "%)\n";
72 std::cerr << " " << Must << " must alias responses (" <<Must*100/Sum<<"%)\n";