//===- llvm/Analysis/AliasAnalysis.h - Alias Analysis Interface -*- C++ -*-===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file defines the generic AliasAnalysis interface, which is used as the
#define LLVM_ANALYSIS_ALIAS_ANALYSIS_H
#include "llvm/Support/CallSite.h"
-#include "llvm/Pass.h" // Need this for IncludeFile
+#include "llvm/System/IncludeFile.h"
+#include <vector>
namespace llvm {
class LoadInst;
class StoreInst;
+class VAArgInst;
class TargetData;
+class Pass;
+class AnalysisUsage;
class AliasAnalysis {
protected:
/// called multiple times.
///
void InitializeAliasAnalysis(Pass *P);
-
- // getAnalysisUsage - All alias analysis implementations should invoke this
- // directly (using AliasAnalysis::getAnalysisUsage(AU)) to make sure that
- // TargetData is required by the pass.
+
+ /// getAnalysisUsage - All alias analysis implementations should invoke this
+ /// directly (using AliasAnalysis::getAnalysisUsage(AU)).
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
public:
+ static char ID; // Class identification, replacement for typeinfo
AliasAnalysis() : TD(0), AA(0) {}
virtual ~AliasAnalysis(); // We want to be subclassed
- /// getTargetData - Every alias analysis implementation depends on the size of
- /// data items in the current Target. This provides a uniform way to handle
- /// it.
+ /// getTargetData - Return a pointer to the current TargetData object, or
+ /// null if no TargetData object is available.
+ ///
+ const TargetData *getTargetData() const { return TD; }
+
+ /// getTypeStoreSize - Return the TargetData store size for the given type,
+ /// if known, or a conservative value otherwise.
///
- const TargetData &getTargetData() const { return *TD; }
+ unsigned getTypeStoreSize(const Type *Ty);
//===--------------------------------------------------------------------===//
/// Alias Queries...
/// bits which may be or'd together.
///
enum ModRefResult { NoModRef = 0, Ref = 1, Mod = 2, ModRef = 3 };
-
-
+
+
/// ModRefBehavior - Summary of how a function affects memory in the program.
/// Loads from constant globals are not considered memory accesses for this
/// interface. Also, functions may freely modify stack space local to their
//
// This property corresponds to the GCC 'const' attribute.
DoesNotAccessMemory,
-
- // AccessesArguments - This function accesses function arguments in
- // non-volatile and well known ways, but does not access any other memory.
+
+ // AccessesArguments - This function accesses function arguments in well
+ // known (possibly volatile) ways, but does not access any other memory.
//
- // Clients may call getArgumentAccesses to get specific information about
- // how pointer arguments are used.
+ // Clients may use the Info parameter of getModRefBehavior to get specific
+ // information about how pointer arguments are used.
AccessesArguments,
-
+
// AccessesArgumentsAndGlobals - This function has accesses function
- // arguments and global variables in non-volatile and well-known ways, but
+ // arguments and global variables well known (possibly volatile) ways, but
// does not access any other memory.
//
- // Clients may call getArgumentAccesses to get specific information about
- // how pointer arguments and globals are used.
+ // Clients may use the Info parameter of getModRefBehavior to get specific
+ // information about how pointer arguments are used.
AccessesArgumentsAndGlobals,
-
+
// OnlyReadsMemory - This function does not perform any non-local stores or
// volatile loads, but may read from any memory location.
//
// This property corresponds to the GCC 'pure' attribute.
OnlyReadsMemory,
-
+
// UnknownModRefBehavior - This indicates that the function could not be
// classified into one of the behaviors above.
UnknownModRefBehavior
};
-
+
/// PointerAccessInfo - This struct is used to return results for pointers,
/// globals, and the return value of a function.
struct PointerAccessInfo {
/// the function, a GlobalVariable, or null, corresponding to the return
/// value for the function.
Value *V;
-
+
/// ModRefInfo - Whether the pointer is loaded or stored to/from.
///
ModRefResult ModRefInfo;
-
+
/// AccessType - Specific fine-grained access information for the argument.
/// If none of these classifications is general enough, the
/// getModRefBehavior method should not return AccessesArguments*. If a
/// ScalarAccess - The pointer is dereferenced.
///
ScalarAccess,
-
+
/// ArrayAccess - The pointer is indexed through as an array of elements.
///
ArrayAccess,
-
+
/// ElementAccess ?? P->F only?
-
+
/// CallsThrough - Indirect calls are made through the specified function
/// pointer.
- CallsThrough,
+ CallsThrough
};
- };
-
- /// getModRefBehavior - Return the behavior of the specified function if
- /// called from the specified call site. The call site may be null in which
- /// case the most generic behavior of this function should be returned.
- virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
- std::vector<PointerAccessInfo> *Info = 0);
-
- /// doesNotAccessMemory - If the specified function is known to never read or
- /// write memory, return true. If the function only reads from known-constant
- /// memory, it is also legal to return true. Functions that unwind the stack
- /// are not legal for this predicate.
+ };
+
+ /// getModRefBehavior - Return the behavior when calling the given call site.
+ virtual ModRefBehavior getModRefBehavior(CallSite CS,
+ std::vector<PointerAccessInfo> *Info = 0);
+
+ /// getModRefBehavior - Return the behavior when calling the given function.
+ /// For use when the call site is not known.
+ virtual ModRefBehavior getModRefBehavior(Function *F,
+ std::vector<PointerAccessInfo> *Info = 0);
+
+ /// doesNotAccessMemory - If the specified call is known to never read or
+ /// write memory, return true. If the call only reads from known-constant
+ /// memory, it is also legal to return true. Calls that unwind the stack
+ /// are legal for this predicate.
///
- /// Many optimizations (such as CSE and LICM) can be performed on calls to it,
- /// without worrying about aliasing properties, and many functions have this
- /// property (e.g. 'sin' and 'cos').
+ /// Many optimizations (such as CSE and LICM) can be performed on such calls
+ /// without worrying about aliasing properties, and many calls have this
+ /// property (e.g. calls to 'sin' and 'cos').
///
/// This property corresponds to the GCC 'const' attribute.
///
+ bool doesNotAccessMemory(CallSite CS) {
+ return getModRefBehavior(CS) == DoesNotAccessMemory;
+ }
+
+ /// doesNotAccessMemory - If the specified function is known to never read or
+ /// write memory, return true. For use when the call site is not known.
+ ///
bool doesNotAccessMemory(Function *F) {
- return getModRefBehavior(F, CallSite()) == DoesNotAccessMemory;
+ return getModRefBehavior(F) == DoesNotAccessMemory;
}
- /// onlyReadsMemory - If the specified function is known to only read from
- /// non-volatile memory (or not access memory at all), return true. Functions
- /// that unwind the stack are not legal for this predicate.
+ /// onlyReadsMemory - If the specified call is known to only read from
+ /// non-volatile memory (or not access memory at all), return true. Calls
+ /// that unwind the stack are legal for this predicate.
///
/// This property allows many common optimizations to be performed in the
/// absence of interfering store instructions, such as CSE of strlen calls.
///
/// This property corresponds to the GCC 'pure' attribute.
///
+ bool onlyReadsMemory(CallSite CS) {
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ return MRB == DoesNotAccessMemory || MRB == OnlyReadsMemory;
+ }
+
+ /// onlyReadsMemory - If the specified function is known to only read from
+ /// non-volatile memory (or not access memory at all), return true. For use
+ /// when the call site is not known.
+ ///
bool onlyReadsMemory(Function *F) {
- /// FIXME: If the analysis returns more precise info, we can reduce it to
- /// this.
- return getModRefBehavior(F, CallSite()) == OnlyReadsMemory;
+ ModRefBehavior MRB = getModRefBehavior(F);
+ return MRB == DoesNotAccessMemory || MRB == OnlyReadsMemory;
}
///
virtual bool hasNoModRefInfoForCalls() const;
+public:
/// Convenience functions...
ModRefResult getModRefInfo(LoadInst *L, Value *P, unsigned Size);
ModRefResult getModRefInfo(StoreInst *S, Value *P, unsigned Size);
ModRefResult getModRefInfo(InvokeInst *I, Value *P, unsigned Size) {
return getModRefInfo(CallSite(I), P, Size);
}
+ ModRefResult getModRefInfo(VAArgInst* I, Value* P, unsigned Size) {
+ return AliasAnalysis::ModRef;
+ }
ModRefResult getModRefInfo(Instruction *I, Value *P, unsigned Size) {
switch (I->getOpcode()) {
+ case Instruction::VAArg: return getModRefInfo((VAArgInst*)I, P, Size);
case Instruction::Load: return getModRefInfo((LoadInst*)I, P, Size);
case Instruction::Store: return getModRefInfo((StoreInst*)I, P, Size);
case Instruction::Call: return getModRefInfo((CallInst*)I, P, Size);
}
};
+/// isNoAliasCall - Return true if this pointer is returned by a noalias
+/// function.
+bool isNoAliasCall(const Value *V);
+
+/// isIdentifiedObject - Return true if this pointer refers to a distinct and
+/// identifiable object. This returns true for:
+/// Global Variables and Functions (but not Global Aliases)
+/// Allocas and Mallocs
+/// ByVal and NoAlias Arguments
+/// NoAlias returns
+///
+bool isIdentifiedObject(const Value *V);
+
+} // End llvm namespace
+
// Because of the way .a files work, we must force the BasicAA implementation to
// be pulled in if the AliasAnalysis header is included. Otherwise we run
// the risk of AliasAnalysis being used, but the default implementation not
// being linked into the tool that uses it.
-//
-extern void BasicAAStub();
-static IncludeFile HDR_INCLUDE_BASICAA_CPP((void*)&BasicAAStub);
-
-} // End llvm namespace
+FORCE_DEFINING_FILE_TO_BE_LINKED(AliasAnalysis)
+FORCE_DEFINING_FILE_TO_BE_LINKED(BasicAliasAnalysis)
#endif
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