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//===- llvm/Analysis/AliasAnalysis.h - Alias Analysis Interface -*- C++ -*-===//
//
// This file defines the generic AliasAnalysis interface, which is used as the
// common interface used by all clients of alias analysis information, and
// implemented by all alias analysis implementations.
//
// Implementations of this interface must implement the various virtual methods,
// which automatically provides functionality for the entire suite of client
// APIs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_ALIAS_ANALYSIS_H
#define LLVM_ANALYSIS_ALIAS_ANALYSIS_H
class Value;
class CallInst;
class InvokeInst;
class BasicBlock;
class Instruction;
struct AliasAnalysis {
/// Alias analysis result - Either we know for sure that it does not alias, we
/// know for sure it must alias, or we don't know anything: The two pointers
/// _might_ alias. This enum is designed so you can do things like:
/// if (AA.alias(P1, P2)) { ... }
/// to check to see if two pointers might alias.
///
enum Result { NoAlias = 0, MayAlias = 1, MustAlias = 2 };
/// alias - The main low level interface to the alias analysis implementation.
/// Returns a Result indicating whether the two pointers are aliased to each
/// other. This is the interface that must be implemented by specific alias
/// analysis implementations.
///
virtual Result alias(const Value *V1, const Value *V2) = 0;
/// canCallModify - Return a Result that indicates whether the specified
/// function call can modify the memory location pointed to by Ptr.
///
virtual Result canCallModify(const CallInst &CI, const Value *Ptr) = 0;
/// canInvokeModify - Return a Result that indicates whether the specified
/// function invoke can modify the memory location pointed to by Ptr.
///
virtual Result canInvokeModify(const InvokeInst &I, const Value *Ptr) = 0;
/// canBasicBlockModify - Return true if it is possible for execution of the
/// specified basic block to modify the value pointed to by Ptr.
///
bool canBasicBlockModify(const BasicBlock &BB, const Value *Ptr);
/// canInstructionRangeModify - Return true if it is possible for the
/// execution of the specified instructions to modify the value pointed to by
/// Ptr. The instructions to consider are all of the instructions in the
/// range of [I1,I2] INCLUSIVE. I1 and I2 must be in the same basic block.
///
bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
const Value *Ptr);
virtual ~AliasAnalysis(); // We want to be subclassed
};
#endif
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