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//===- llvm/Analysis/MemoryDependenceAnalysis.h - Memory Deps --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines an analysis that determines, for a given memory operation,
// what preceding memory operations it depends on. It builds on alias analysis
// information, and tries to provide a lazy, caching interface to a common kind
// of alias information query.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_MEMORY_DEPENDENCE_H
#define LLVM_ANALYSIS_MEMORY_DEPENDENCE_H
#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
class Function;
class FunctionPass;
class Instruction;
class MemoryDependenceAnalysis : public FunctionPass {
private:
// A map from instructions to their dependency, with a boolean
// flags for whether this mapping is confirmed or not
typedef DenseMap<Instruction*, std::pair<Instruction*, bool> >
depMapType;
depMapType depGraphLocal;
// A map from instructions to their non-local dependencies.
typedef DenseMap<Instruction*, DenseMap<BasicBlock*, Value*> >
nonLocalDepMapType;
nonLocalDepMapType depGraphNonLocal;
// A reverse mapping form dependencies to the dependees. This is
// used when removing instructions to keep the cache coherent.
typedef DenseMap<Value*, SmallPtrSet<Instruction*, 4> >
reverseDepMapType;
reverseDepMapType reverseDep;
// A reverse mapping form dependencies to the non-local dependees.
reverseDepMapType reverseDepNonLocal;
public:
void ping(Instruction* D);
// Special marker indicating that the query has no dependency
// in the specified block.
static Instruction* const NonLocal;
// Special marker indicating that the query has no dependency at all
static Instruction* const None;
// Special marker indicating a dirty cache entry
static Instruction* const Dirty;
static char ID; // Class identification, replacement for typeinfo
MemoryDependenceAnalysis() : FunctionPass(&ID) {}
/// Pass Implementation stuff. This doesn't do any analysis.
///
bool runOnFunction(Function &) {return false; }
/// Clean up memory in between runs
void releaseMemory() {
depGraphLocal.clear();
depGraphNonLocal.clear();
reverseDep.clear();
reverseDepNonLocal.clear();
}
/// getAnalysisUsage - Does not modify anything. It uses Value Numbering
/// and Alias Analysis.
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
/// getDependency - Return the instruction on which a memory operation
/// depends, starting with start.
Instruction* getDependency(Instruction* query, Instruction* start = 0,
BasicBlock* block = 0);
/// getNonLocalDependency - Fills the passed-in map with the non-local
/// dependencies of the queries. The map will contain NonLocal for
/// blocks between the query and its dependencies.
void getNonLocalDependency(Instruction* query,
DenseMap<BasicBlock*, Value*>& resp);
/// removeInstruction - Remove an instruction from the dependence analysis,
/// updating the dependence of instructions that previously depended on it.
void removeInstruction(Instruction* rem);
/// dropInstruction - Remove an instruction from the analysis, making
/// absolutely conservative assumptions when updating the cache. This is
/// useful, for example when an instruction is changed rather than removed.
void dropInstruction(Instruction* drop);
private:
Instruction* getCallSiteDependency(CallSite C, Instruction* start,
BasicBlock* block);
void nonLocalHelper(Instruction* query, BasicBlock* block,
DenseMap<BasicBlock*, Value*>& resp);
};
} // End llvm namespace
#endif
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