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//===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Andrew Lenharth and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This simple pass checks alias analysis users to ensure that if they
// create a new value, they do not query AA without informing it of the value.
// It acts as a shim over any other AA pass you want.
//
// Yes keeping track of every value in the program is expensive, but this is
// a debugging pass.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Passes.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Instructions.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Support/Compiler.h"
#include <set>
using namespace llvm;
namespace {
class VISIBILITY_HIDDEN AliasDebugger
: public ModulePass, public AliasAnalysis {
//What we do is simple. Keep track of every value the AA could
//know about, and verify that queries are one of those.
//A query to a value that didn't exist when the AA was created
//means someone forgot to update the AA when creating new values
std::set<const Value*> Vals;
public:
static const char ID; // Class identification, replacement for typeinfo
AliasDebugger() : ModulePass((intptr_t)&ID) {}
bool runOnModule(Module &M) {
InitializeAliasAnalysis(this); // set up super class
for(Module::global_iterator I = M.global_begin(),
E = M.global_end(); I != E; ++I)
Vals.insert(&*I);
for(Module::iterator I = M.begin(),
E = M.end(); I != E; ++I){
Vals.insert(&*I);
if(!I->isDeclaration()) {
for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end();
AI != AE; ++AI)
Vals.insert(&*AI);
for (Function::const_iterator FI = I->begin(), FE = I->end();
FI != FE; ++FI)
for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI)
Vals.insert(&*BI);
}
}
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AliasAnalysis::getAnalysisUsage(AU);
AU.setPreservesAll(); // Does not transform code
}
//------------------------------------------------
// Implement the AliasAnalysis API
//
AliasResult alias(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size) {
assert(Vals.find(V1) != Vals.end() && "Never seen value in AA before");
assert(Vals.find(V2) != Vals.end() && "Never seen value in AA before");
return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
}
ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) {
assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
return AliasAnalysis::getModRefInfo(CS, P, Size);
}
ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
return AliasAnalysis::getModRefInfo(CS1,CS2);
}
void getMustAliases(Value *P, std::vector<Value*> &RetVals) {
assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
return AliasAnalysis::getMustAliases(P, RetVals);
}
bool pointsToConstantMemory(const Value *P) {
assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
return AliasAnalysis::pointsToConstantMemory(P);
}
/// getModRefBehavior - Return the behavior of the specified function if
/// called from the specified call site. The call site may be null in which
/// case the most generic behavior of this function should be returned.
virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
std::vector<PointerAccessInfo> *Info) {
assert(Vals.find(F) != Vals.end() && "Never seen value in AA before");
return AliasAnalysis::getModRefBehavior(F, CS, Info);
}
virtual void deleteValue(Value *V) {
assert(Vals.find(V) != Vals.end() && "Never seen value in AA before");
AliasAnalysis::deleteValue(V);
}
virtual void copyValue(Value *From, Value *To) {
Vals.insert(To);
AliasAnalysis::copyValue(From, To);
}
};
const char AliasDebugger::ID = 0;
RegisterPass<AliasDebugger> X("debug-aa", "AA use debugger");
RegisterAnalysisGroup<AliasAnalysis> Y(X);
}
Pass *llvm::createAliasDebugger() { return new AliasDebugger(); }
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