1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a simple N^2 alias analysis accuracy evaluator.
11 // Basically, for each function in the program, it simply queries to see how the
12 // alias analysis implementation answers alias queries between each pair of
13 // pointers in the function.
15 // This is inspired and adapted from code by: Naveen Neelakantam, Francesco
16 // Spadini, and Wojciech Stryjewski.
18 //===----------------------------------------------------------------------===//
20 #include "llvm/Analysis/AliasAnalysis.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Function.h"
23 #include "llvm/Type.h"
24 #include "llvm/Support/InstIterator.h"
25 #include "llvm/Assembly/Writer.h"
26 #include "Support/CommandLine.h"
30 cl::opt<bool> PrintNo ("print-no-aliases", cl::ReallyHidden);
31 cl::opt<bool> PrintMay ("print-may-aliases", cl::ReallyHidden);
32 cl::opt<bool> PrintMust("print-must-aliases", cl::ReallyHidden);
34 class AAEval : public FunctionPass {
35 unsigned No, May, Must;
38 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
39 AU.addRequired<AliasAnalysis>();
43 bool doInitialization(Module &M) { No = May = Must = 0; return false; }
44 bool runOnFunction(Function &F);
45 bool doFinalization(Module &M);
49 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
52 static inline void PrintResults(const char *Msg, bool P, Value *V1, Value *V2) {
54 std::cerr << " " << Msg << ":\t";
55 WriteAsOperand(std::cerr, V1) << ", ";
56 WriteAsOperand(std::cerr, V2) << "\n";
60 bool AAEval::runOnFunction(Function &F) {
61 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
63 std::set<Value *> Pointers;
65 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
66 if (isa<PointerType>(I->getType())) // Add all pointer arguments
69 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
70 if (isa<PointerType>((*I)->getType())) // Add all pointer instructions
72 for (User::op_iterator OI = (*I)->op_begin(); OI != (*I)->op_end(); ++OI)
73 if (isa<PointerType>((*OI)->getType()))
77 if (PrintNo || PrintMay || PrintMust)
78 std::cerr << "Function: " << F.getName() << "\n";
80 // iterate over the worklist, and run the full (n^2)/2 disambiguations
81 for (std::set<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
83 for (std::set<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2)
84 switch (AA.alias(*I1, 0, *I2, 0)) {
85 case AliasAnalysis::NoAlias:
86 PrintResults("No", PrintNo, *I1, *I2);
88 case AliasAnalysis::MayAlias:
89 PrintResults("May", PrintMay, *I1, *I2);
91 case AliasAnalysis::MustAlias:
92 PrintResults("Must", PrintMust, *I1, *I2);
95 std::cerr << "Unknown alias query result!\n";
101 bool AAEval::doFinalization(Module &M) {
102 unsigned Sum = No+May+Must;
103 std::cerr << "===== Alias Analysis Evaluator Report =====\n";
105 std::cerr << " Alias Analysis Evaluator Summary: No pointers!\n";
109 std::cerr << " " << Sum << " Total Alias Queries Performed\n";
110 std::cerr << " " << No << " no alias responses (" << No*100/Sum << "%)\n";
111 std::cerr << " " << May << " may alias responses (" << May*100/Sum << "%)\n";
112 std::cerr << " " << Must << " must alias responses (" <<Must*100/Sum<<"%)\n";
113 std::cerr << " Alias Analysis Evaluator Summary: " << No*100/Sum << "%/"
114 << May*100/Sum << "%/" << Must*100/Sum<<"%\n";