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//===- LiveVariables.h - Live Variable Analysis for Source CFGs -*- C++ --*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Ted Kremenek and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements Live Variables analysis for source-level CFGs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIVEVARIABLES_H
#define LLVM_CLANG_LIVEVARIABLES_H
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include <iosfwd>
#include <vector>
namespace clang {
class Stmt;
class DeclRefStmt;
class Decl;
class CFG;
class CFGBlock;
class LiveVariables {
public:
struct VarInfo {
/// AliveBlocks - Set of blocks of which this value is alive completely
/// through. This is a bit set which uses the basic block number as an
/// index.
llvm::BitVector AliveBlocks;
/// Kills - List of statements which are the last use of a variable
/// (kill it) in their basic block. The first pointer in the pair
/// is the statement in the list of statements of a basic block where
/// this occurs, while the DeclRefStmt is the subexpression of this
/// statement where the actual last reference takes place.
std::vector< std::pair<const Stmt*,const DeclRefStmt*> > Kills;
void print(std::ostream& OS) const;
};
struct VPair {
VarInfo V;
unsigned Idx;
};
typedef llvm::DenseMap<const Decl*, VPair > VarInfoMap;
typedef llvm::DenseMap<const CFGBlock*, llvm::BitVector > BlockLivenessMap;
public:
LiveVariables() : NumDecls(0) {}
/// runOnCFG - Computes live variable information for a given CFG.
void runOnCFG(const CFG& cfg);
/// KillsVar - Return true if the specified statement kills the
/// specified variable.
bool KillsVar(const Stmt* S, const Decl* D) const;
/// IsLive - Return true if a variable is live at beginning of a specified
// block.
bool IsLive(const CFGBlock* B, const Decl* D) const;
/// getVarInfo - Return the liveness information associated with a given
/// variable.
VarInfo& getVarInfo(const Decl* D);
const VarInfo& getVarInfo(const Decl* D) const;
/// getVarInfoMap
VarInfoMap& getVarInfoMap() { return VarInfos; }
const VarInfoMap& getVarInfoMap() const { return VarInfos; }
// printLiveness
void printLiveness(const llvm::BitVector& V, std::ostream& OS) const;
// printBlockLiveness
void printBlockLiveness(std::ostream& OS) const;
void DumpBlockLiveness() const;
// getLiveAtBlockEntryMap
BlockLivenessMap& getLiveAtBlockEntryMap() { return LiveAtBlockEntryMap; }
const BlockLivenessMap& getLiveAtBlockEntryMap() const {
return LiveAtBlockEntryMap;
}
// getNumDecls
unsigned& getNumDecls() { return NumDecls; }
unsigned getNumDecls() const { return NumDecls; }
protected:
unsigned NumDecls;
VarInfoMap VarInfos;
BlockLivenessMap LiveAtBlockEntryMap;
};
} // end namespace clang
#endif
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