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//===- llvm/PassAnalysisSupport.h - Analysis Pass Support code --*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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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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// This file defines stuff that is used to define and "use" Analysis Passes.
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// This file is automatically #included by Pass.h, so:
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// NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
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// Instead, #include Pass.h
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_PASS_ANALYSIS_SUPPORT_H
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#define LLVM_PASS_ANALYSIS_SUPPORT_H
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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//===----------------------------------------------------------------------===//
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// AnalysisUsage - Represent the analysis usage information of a pass. This
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// tracks analyses that the pass REQUIRES (must be available when the pass
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// runs), REQUIRES TRANSITIVE (must be available throughout the lifetime of the
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// pass), and analyses that the pass PRESERVES (the pass does not invalidate the
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// results of these analyses). This information is provided by a pass to the
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// Pass infrastructure through the getAnalysisUsage virtual function.
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typedef SmallVector<AnalysisID, 32> VectorType;
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// Sets of analyses required and preserved by a pass
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VectorType Required, RequiredTransitive, Preserved;
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AnalysisUsage() : PreservesAll(false) {}
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// addRequired - Add the specified ID to the required set of the usage info
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AnalysisUsage &addRequiredID(const void *ID);
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AnalysisUsage &addRequiredID(char &ID);
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template<class PassClass>
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AnalysisUsage &addRequired() {
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return addRequiredID(PassClass::ID);
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AnalysisUsage &addRequiredTransitiveID(char &ID);
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template<class PassClass>
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AnalysisUsage &addRequiredTransitive() {
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return addRequiredTransitiveID(PassClass::ID);
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// addPreserved - Add the specified ID to the set of analyses preserved by
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AnalysisUsage &addPreservedID(const void *ID) {
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Preserved.push_back(ID);
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AnalysisUsage &addPreservedID(char &ID) {
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Preserved.push_back(&ID);
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// addPreserved - Add the specified Pass class to the set of analyses
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// preserved by this pass.
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template<class PassClass>
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AnalysisUsage &addPreserved() {
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Preserved.push_back(&PassClass::ID);
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// addPreserved - Add the Pass with the specified argument string to the set
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// of analyses preserved by this pass. If no such Pass exists, do nothing.
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// This can be useful when a pass is trivially preserved, but may not be
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// linked in. Be careful about spelling!
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AnalysisUsage &addPreserved(StringRef Arg);
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// setPreservesAll - Set by analyses that do not transform their input at all
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void setPreservesAll() { PreservesAll = true; }
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bool getPreservesAll() const { return PreservesAll; }
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/// setPreservesCFG - This function should be called by the pass, iff they do
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/// 1. Add or remove basic blocks from the function
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/// 2. Modify terminator instructions in any way.
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/// This function annotates the AnalysisUsage info object to say that analyses
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/// that only depend on the CFG are preserved by this pass.
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void setPreservesCFG();
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const VectorType &getRequiredSet() const { return Required; }
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const VectorType &getRequiredTransitiveSet() const {
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return RequiredTransitive;
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const VectorType &getPreservedSet() const { return Preserved; }
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//===----------------------------------------------------------------------===//
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// AnalysisResolver - Simple interface used by Pass objects to pull all
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// analysis information out of pass manager that is responsible to manage
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class AnalysisResolver {
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AnalysisResolver(); // DO NOT IMPLEMENT
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explicit AnalysisResolver(PMDataManager &P) : PM(P) { }
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inline PMDataManager &getPMDataManager() { return PM; }
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// Find pass that is implementing PI.
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Pass *findImplPass(AnalysisID PI) {
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Pass *ResultPass = 0;
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for (unsigned i = 0; i < AnalysisImpls.size() ; ++i) {
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if (AnalysisImpls[i].first == PI) {
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ResultPass = AnalysisImpls[i].second;
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// Find pass that is implementing PI. Initialize pass for Function F.
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Pass *findImplPass(Pass *P, AnalysisID PI, Function &F);
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void addAnalysisImplsPair(AnalysisID PI, Pass *P) {
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std::pair<AnalysisID, Pass*> pir = std::make_pair(PI,P);
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AnalysisImpls.push_back(pir);
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/// clearAnalysisImpls - Clear cache that is used to connect a pass to the
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/// the analysis (PassInfo).
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void clearAnalysisImpls() {
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AnalysisImpls.clear();
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// getAnalysisIfAvailable - Return analysis result or null if it doesn't exist
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Pass *getAnalysisIfAvailable(AnalysisID ID, bool Direction) const;
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// AnalysisImpls - This keeps track of which passes implements the interfaces
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// that are required by the current pass (to implement getAnalysis()).
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std::vector<std::pair<AnalysisID, Pass*> > AnalysisImpls;
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// PassManager that is used to resolve analysis info
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/// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
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/// get analysis information that might be around, for example to update it.
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/// This is different than getAnalysis in that it can fail (if the analysis
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/// results haven't been computed), so should only be used if you can handle
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/// the case when the analysis is not available. This method is often used by
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/// transformation APIs to update analysis results for a pass automatically as
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/// the transform is performed.
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template<typename AnalysisType>
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AnalysisType *Pass::getAnalysisIfAvailable() const {
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assert(Resolver && "Pass not resident in a PassManager object!");
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const void *PI = &AnalysisType::ID;
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Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
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if (ResultPass == 0) return 0;
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// Because the AnalysisType may not be a subclass of pass (for
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// AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
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// adjust the return pointer (because the class may multiply inherit, once
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// from pass, once from AnalysisType).
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return (AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
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/// getAnalysis<AnalysisType>() - This function is used by subclasses to get
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/// to the analysis information that they claim to use by overriding the
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/// getAnalysisUsage function.
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template<typename AnalysisType>
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AnalysisType &Pass::getAnalysis() const {
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assert(Resolver && "Pass has not been inserted into a PassManager object!");
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return getAnalysisID<AnalysisType>(&AnalysisType::ID);
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template<typename AnalysisType>
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AnalysisType &Pass::getAnalysisID(AnalysisID PI) const {
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assert(PI && "getAnalysis for unregistered pass!");
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assert(Resolver&&"Pass has not been inserted into a PassManager object!");
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// PI *must* appear in AnalysisImpls. Because the number of passes used
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// should be a small number, we just do a linear search over a (dense)
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Pass *ResultPass = Resolver->findImplPass(PI);
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assert (ResultPass &&
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"getAnalysis*() called on an analysis that was not "
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"'required' by pass!");
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// Because the AnalysisType may not be a subclass of pass (for
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// AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
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// adjust the return pointer (because the class may multiply inherit, once
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// from pass, once from AnalysisType).
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return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
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/// getAnalysis<AnalysisType>() - This function is used by subclasses to get
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/// to the analysis information that they claim to use by overriding the
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/// getAnalysisUsage function.
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template<typename AnalysisType>
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AnalysisType &Pass::getAnalysis(Function &F) {
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assert(Resolver &&"Pass has not been inserted into a PassManager object!");
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return getAnalysisID<AnalysisType>(&AnalysisType::ID, F);
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template<typename AnalysisType>
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AnalysisType &Pass::getAnalysisID(AnalysisID PI, Function &F) {
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assert(PI && "getAnalysis for unregistered pass!");
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assert(Resolver && "Pass has not been inserted into a PassManager object!");
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// PI *must* appear in AnalysisImpls. Because the number of passes used
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// should be a small number, we just do a linear search over a (dense)
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Pass *ResultPass = Resolver->findImplPass(this, PI, F);
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assert(ResultPass && "Unable to find requested analysis info");
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// Because the AnalysisType may not be a subclass of pass (for
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// AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
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// adjust the return pointer (because the class may multiply inherit, once
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// from pass, once from AnalysisType).
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return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
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} // End llvm namespace