forked from OSchip/llvm-project
399 lines
14 KiB
C++
399 lines
14 KiB
C++
//===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a simple N^2 alias analysis accuracy evaluator.
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// Basically, for each function in the program, it simply queries to see how the
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// alias analysis implementation answers alias queries between each pair of
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// pointers in the function.
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//
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// This is inspired and adapted from code by: Naveen Neelakantam, Francesco
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// Spadini, and Wojciech Stryjewski.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Passes.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
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static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
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static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
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static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
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static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
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static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
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static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
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static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
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static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
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static cl::opt<bool> EvalAAMD("evaluate-aa-metadata", cl::ReallyHidden);
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namespace {
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class AAEval : public FunctionPass {
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unsigned NoAliasCount, MayAliasCount, PartialAliasCount, MustAliasCount;
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unsigned NoModRefCount, ModCount, RefCount, ModRefCount;
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public:
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static char ID; // Pass identification, replacement for typeid
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AAEval() : FunctionPass(ID) {
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initializeAAEvalPass(*PassRegistry::getPassRegistry());
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequired<AliasAnalysis>();
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AU.setPreservesAll();
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}
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bool doInitialization(Module &M) override {
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NoAliasCount = MayAliasCount = PartialAliasCount = MustAliasCount = 0;
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NoModRefCount = ModCount = RefCount = ModRefCount = 0;
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if (PrintAll) {
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PrintNoAlias = PrintMayAlias = true;
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PrintPartialAlias = PrintMustAlias = true;
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PrintNoModRef = PrintMod = PrintRef = PrintModRef = true;
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}
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return false;
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}
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bool runOnFunction(Function &F) override;
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bool doFinalization(Module &M) override;
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};
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}
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char AAEval::ID = 0;
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INITIALIZE_PASS_BEGIN(AAEval, "aa-eval",
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"Exhaustive Alias Analysis Precision Evaluator", false, true)
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INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
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INITIALIZE_PASS_END(AAEval, "aa-eval",
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"Exhaustive Alias Analysis Precision Evaluator", false, true)
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FunctionPass *llvm::createAAEvalPass() { return new AAEval(); }
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static void PrintResults(const char *Msg, bool P, const Value *V1,
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const Value *V2, const Module *M) {
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if (P) {
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std::string o1, o2;
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{
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raw_string_ostream os1(o1), os2(o2);
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V1->printAsOperand(os1, true, M);
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V2->printAsOperand(os2, true, M);
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}
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if (o2 < o1)
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std::swap(o1, o2);
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errs() << " " << Msg << ":\t"
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<< o1 << ", "
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<< o2 << "\n";
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}
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}
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static inline void
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PrintModRefResults(const char *Msg, bool P, Instruction *I, Value *Ptr,
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Module *M) {
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if (P) {
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errs() << " " << Msg << ": Ptr: ";
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Ptr->printAsOperand(errs(), true, M);
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errs() << "\t<->" << *I << '\n';
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}
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}
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static inline void
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PrintModRefResults(const char *Msg, bool P, CallSite CSA, CallSite CSB,
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Module *M) {
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if (P) {
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errs() << " " << Msg << ": " << *CSA.getInstruction()
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<< " <-> " << *CSB.getInstruction() << '\n';
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}
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}
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static inline void
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PrintLoadStoreResults(const char *Msg, bool P, const Value *V1,
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const Value *V2, const Module *M) {
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if (P) {
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errs() << " " << Msg << ": " << *V1
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<< " <-> " << *V2 << '\n';
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}
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}
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static inline bool isInterestingPointer(Value *V) {
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return V->getType()->isPointerTy()
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&& !isa<ConstantPointerNull>(V);
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}
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bool AAEval::runOnFunction(Function &F) {
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const DataLayout &DL = F.getParent()->getDataLayout();
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AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
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SetVector<Value *> Pointers;
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SetVector<CallSite> CallSites;
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SetVector<Value *> Loads;
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SetVector<Value *> Stores;
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for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
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if (I->getType()->isPointerTy()) // Add all pointer arguments.
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Pointers.insert(I);
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for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
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if (I->getType()->isPointerTy()) // Add all pointer instructions.
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Pointers.insert(&*I);
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if (EvalAAMD && isa<LoadInst>(&*I))
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Loads.insert(&*I);
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if (EvalAAMD && isa<StoreInst>(&*I))
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Stores.insert(&*I);
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Instruction &Inst = *I;
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if (auto CS = CallSite(&Inst)) {
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Value *Callee = CS.getCalledValue();
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// Skip actual functions for direct function calls.
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if (!isa<Function>(Callee) && isInterestingPointer(Callee))
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Pointers.insert(Callee);
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// Consider formals.
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for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
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AI != AE; ++AI)
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if (isInterestingPointer(*AI))
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Pointers.insert(*AI);
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CallSites.insert(CS);
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} else {
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// Consider all operands.
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for (Instruction::op_iterator OI = Inst.op_begin(), OE = Inst.op_end();
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OI != OE; ++OI)
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if (isInterestingPointer(*OI))
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Pointers.insert(*OI);
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}
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}
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if (PrintNoAlias || PrintMayAlias || PrintPartialAlias || PrintMustAlias ||
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PrintNoModRef || PrintMod || PrintRef || PrintModRef)
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errs() << "Function: " << F.getName() << ": " << Pointers.size()
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<< " pointers, " << CallSites.size() << " call sites\n";
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// iterate over the worklist, and run the full (n^2)/2 disambiguations
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for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
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I1 != E; ++I1) {
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uint64_t I1Size = MemoryLocation::UnknownSize;
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Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
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if (I1ElTy->isSized()) I1Size = DL.getTypeStoreSize(I1ElTy);
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for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
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uint64_t I2Size = MemoryLocation::UnknownSize;
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Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
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if (I2ElTy->isSized()) I2Size = DL.getTypeStoreSize(I2ElTy);
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switch (AA.alias(*I1, I1Size, *I2, I2Size)) {
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case NoAlias:
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PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
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++NoAliasCount;
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break;
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case MayAlias:
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PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
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++MayAliasCount;
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break;
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case PartialAlias:
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PrintResults("PartialAlias", PrintPartialAlias, *I1, *I2,
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F.getParent());
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++PartialAliasCount;
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break;
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case MustAlias:
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PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
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++MustAliasCount;
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break;
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}
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}
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}
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if (EvalAAMD) {
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// iterate over all pairs of load, store
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for (SetVector<Value *>::iterator I1 = Loads.begin(), E = Loads.end();
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I1 != E; ++I1) {
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for (SetVector<Value *>::iterator I2 = Stores.begin(), E2 = Stores.end();
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I2 != E2; ++I2) {
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switch (AA.alias(MemoryLocation::get(cast<LoadInst>(*I1)),
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MemoryLocation::get(cast<StoreInst>(*I2)))) {
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case NoAlias:
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PrintLoadStoreResults("NoAlias", PrintNoAlias, *I1, *I2,
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F.getParent());
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++NoAliasCount;
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break;
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case MayAlias:
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PrintLoadStoreResults("MayAlias", PrintMayAlias, *I1, *I2,
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F.getParent());
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++MayAliasCount;
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break;
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case PartialAlias:
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PrintLoadStoreResults("PartialAlias", PrintPartialAlias, *I1, *I2,
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F.getParent());
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++PartialAliasCount;
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break;
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case MustAlias:
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PrintLoadStoreResults("MustAlias", PrintMustAlias, *I1, *I2,
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F.getParent());
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++MustAliasCount;
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break;
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}
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}
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}
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// iterate over all pairs of store, store
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for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
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I1 != E; ++I1) {
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for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
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switch (AA.alias(MemoryLocation::get(cast<StoreInst>(*I1)),
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MemoryLocation::get(cast<StoreInst>(*I2)))) {
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case NoAlias:
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PrintLoadStoreResults("NoAlias", PrintNoAlias, *I1, *I2,
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F.getParent());
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++NoAliasCount;
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break;
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case MayAlias:
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PrintLoadStoreResults("MayAlias", PrintMayAlias, *I1, *I2,
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F.getParent());
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++MayAliasCount;
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break;
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case PartialAlias:
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PrintLoadStoreResults("PartialAlias", PrintPartialAlias, *I1, *I2,
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F.getParent());
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++PartialAliasCount;
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break;
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case MustAlias:
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PrintLoadStoreResults("MustAlias", PrintMustAlias, *I1, *I2,
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F.getParent());
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++MustAliasCount;
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break;
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}
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}
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}
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}
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// Mod/ref alias analysis: compare all pairs of calls and values
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for (SetVector<CallSite>::iterator C = CallSites.begin(),
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Ce = CallSites.end(); C != Ce; ++C) {
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Instruction *I = C->getInstruction();
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for (SetVector<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
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V != Ve; ++V) {
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uint64_t Size = MemoryLocation::UnknownSize;
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Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
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if (ElTy->isSized()) Size = DL.getTypeStoreSize(ElTy);
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switch (AA.getModRefInfo(*C, *V, Size)) {
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case MRI_NoModRef:
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PrintModRefResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
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++NoModRefCount;
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break;
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case MRI_Mod:
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PrintModRefResults("Just Mod", PrintMod, I, *V, F.getParent());
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++ModCount;
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break;
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case MRI_Ref:
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PrintModRefResults("Just Ref", PrintRef, I, *V, F.getParent());
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++RefCount;
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break;
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case MRI_ModRef:
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PrintModRefResults("Both ModRef", PrintModRef, I, *V, F.getParent());
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++ModRefCount;
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break;
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}
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}
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}
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// Mod/ref alias analysis: compare all pairs of calls
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for (SetVector<CallSite>::iterator C = CallSites.begin(),
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Ce = CallSites.end(); C != Ce; ++C) {
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for (SetVector<CallSite>::iterator D = CallSites.begin(); D != Ce; ++D) {
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if (D == C)
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continue;
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switch (AA.getModRefInfo(*C, *D)) {
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case MRI_NoModRef:
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PrintModRefResults("NoModRef", PrintNoModRef, *C, *D, F.getParent());
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++NoModRefCount;
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break;
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case MRI_Mod:
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PrintModRefResults("Just Mod", PrintMod, *C, *D, F.getParent());
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++ModCount;
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break;
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case MRI_Ref:
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PrintModRefResults("Just Ref", PrintRef, *C, *D, F.getParent());
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++RefCount;
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break;
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case MRI_ModRef:
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PrintModRefResults("Both ModRef", PrintModRef, *C, *D, F.getParent());
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++ModRefCount;
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break;
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}
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}
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}
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return false;
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}
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static void PrintPercent(unsigned Num, unsigned Sum) {
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errs() << "(" << Num*100ULL/Sum << "."
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<< ((Num*1000ULL/Sum) % 10) << "%)\n";
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}
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bool AAEval::doFinalization(Module &M) {
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unsigned AliasSum =
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NoAliasCount + MayAliasCount + PartialAliasCount + MustAliasCount;
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errs() << "===== Alias Analysis Evaluator Report =====\n";
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if (AliasSum == 0) {
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errs() << " Alias Analysis Evaluator Summary: No pointers!\n";
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} else {
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errs() << " " << AliasSum << " Total Alias Queries Performed\n";
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errs() << " " << NoAliasCount << " no alias responses ";
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PrintPercent(NoAliasCount, AliasSum);
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errs() << " " << MayAliasCount << " may alias responses ";
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PrintPercent(MayAliasCount, AliasSum);
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errs() << " " << PartialAliasCount << " partial alias responses ";
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PrintPercent(PartialAliasCount, AliasSum);
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errs() << " " << MustAliasCount << " must alias responses ";
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PrintPercent(MustAliasCount, AliasSum);
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errs() << " Alias Analysis Evaluator Pointer Alias Summary: "
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<< NoAliasCount * 100 / AliasSum << "%/"
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<< MayAliasCount * 100 / AliasSum << "%/"
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<< PartialAliasCount * 100 / AliasSum << "%/"
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<< MustAliasCount * 100 / AliasSum << "%\n";
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}
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// Display the summary for mod/ref analysis
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unsigned ModRefSum = NoModRefCount + ModCount + RefCount + ModRefCount;
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if (ModRefSum == 0) {
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errs() << " Alias Analysis Mod/Ref Evaluator Summary: no "
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"mod/ref!\n";
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} else {
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errs() << " " << ModRefSum << " Total ModRef Queries Performed\n";
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errs() << " " << NoModRefCount << " no mod/ref responses ";
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PrintPercent(NoModRefCount, ModRefSum);
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errs() << " " << ModCount << " mod responses ";
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PrintPercent(ModCount, ModRefSum);
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errs() << " " << RefCount << " ref responses ";
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PrintPercent(RefCount, ModRefSum);
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errs() << " " << ModRefCount << " mod & ref responses ";
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PrintPercent(ModRefCount, ModRefSum);
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errs() << " Alias Analysis Evaluator Mod/Ref Summary: "
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<< NoModRefCount * 100 / ModRefSum << "%/"
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<< ModCount * 100 / ModRefSum << "%/" << RefCount * 100 / ModRefSum
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<< "%/" << ModRefCount * 100 / ModRefSum << "%\n";
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}
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return false;
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}
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