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/Type.h"
17 #include "llvm/Support/InstIterator.h"
18 #include "llvm/Assembly/Writer.h"
19 #include "Support/CommandLine.h"
22 cl::opt<bool> PrintNo ("print-no-aliases", cl::ReallyHidden);
23 cl::opt<bool> PrintMay ("print-may-aliases", cl::ReallyHidden);
24 cl::opt<bool> PrintMust("print-must-aliases", cl::ReallyHidden);
26 class AAEval : public FunctionPass {
27 unsigned No, May, Must;
30 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
31 AU.addRequired<AliasAnalysis>();
35 bool doInitialization(Module &M) { No = May = Must = 0; return false; }
36 bool runOnFunction(Function &F);
37 bool doFinalization(Module &M);
41 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
44 static inline void PrintResults(const char *Msg, bool P, Value *V1, Value *V2) {
46 std::cerr << " " << Msg << ":\t";
47 WriteAsOperand(std::cerr, V1) << ", ";
48 WriteAsOperand(std::cerr, V2) << "\n";
52 bool AAEval::runOnFunction(Function &F) {
53 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
55 std::vector<Value *> Pointers;
57 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
58 if (isa<PointerType>(I->getType())) // Add all pointer arguments
59 Pointers.push_back(I);
61 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
62 if (isa<PointerType>((*I)->getType())) // Add all pointer instructions
63 Pointers.push_back(*I);
65 if (PrintNo || PrintMay || PrintMust)
66 std::cerr << "Function: " << F.getName() << "\n";
68 // iterate over the worklist, and run the full (n^2)/2 disambiguations
69 for (std::vector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
71 for (std::vector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2)
72 switch (AA.alias(*I1, 0, *I2, 0)) {
73 case AliasAnalysis::NoAlias:
74 PrintResults("No", PrintNo, *I1, *I2);
76 case AliasAnalysis::MayAlias:
77 PrintResults("May", PrintMay, *I1, *I2);
79 case AliasAnalysis::MustAlias:
80 PrintResults("Must", PrintMust, *I1, *I2);
83 std::cerr << "Unknown alias query result!\n";
89 bool AAEval::doFinalization(Module &M) {
90 unsigned Sum = No+May+Must;
91 std::cerr << "===== Alias Analysis Evaluator Report =====\n";
93 std::cerr << " Alias Analysis Evaluator Summary: No pointers!\n";
97 std::cerr << " " << Sum << " Total Alias Queries Performed\n";
98 std::cerr << " " << No << " no alias responses (" << No*100/Sum << "%)\n";
99 std::cerr << " " << May << " may alias responses (" << May*100/Sum << "%)\n";
100 std::cerr << " " << Must << " must alias responses (" <<Must*100/Sum<<"%)\n";
101 std::cerr << " Alias Analysis Evaluator Summary: " << No*100/Sum << "%/"
102 << May*100/Sum << "%/" << Must*100/Sum<<"%\n";