#include "llvm/Function.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Instructions.h"
+#include "llvm/LLVMContext.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
// Register the AliasAnalysis interface, providing a nice name to refer to.
-static RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
+INITIALIZE_ANALYSIS_GROUP(AliasAnalysis, "Alias Analysis", NoAA)
char AliasAnalysis::ID = 0;
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
AliasAnalysis::AliasResult
-AliasAnalysis::alias(const Value *V1, unsigned V1Size,
- const Value *V2, unsigned V2Size) {
+AliasAnalysis::alias(const Location &LocA, const Location &LocB) {
assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
- return AA->alias(V1, V1Size, V2, V2Size);
+ return AA->alias(LocA, LocB);
}
-bool AliasAnalysis::pointsToConstantMemory(const Value *P) {
+bool AliasAnalysis::pointsToConstantMemory(const Location &Loc,
+ bool OrLocal) {
assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
- return AA->pointsToConstantMemory(P);
+ return AA->pointsToConstantMemory(Loc, OrLocal);
}
void AliasAnalysis::deleteValue(Value *V) {
}
AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(CallSite CS1, CallSite CS2) {
- // FIXME: we can do better.
+AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
+ const Location &Loc) {
assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
- return AA->getModRefInfo(CS1, CS2);
-}
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ if (MRB == DoesNotAccessMemory)
+ return NoModRef;
-//===----------------------------------------------------------------------===//
-// AliasAnalysis non-virtual helper method implementation
-//===----------------------------------------------------------------------===//
+ ModRefResult Mask = ModRef;
+ if (onlyReadsMemory(MRB))
+ Mask = Ref;
-AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(LoadInst *L, Value *P, unsigned Size) {
- return alias(L->getOperand(0), getTypeStoreSize(L->getType()),
- P, Size) ? Ref : NoModRef;
+ if (onlyAccessesArgPointees(MRB)) {
+ bool doesAlias = false;
+ if (doesAccessArgPointees(MRB))
+ for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+ AI != AE; ++AI)
+ if (!isNoAlias(Location(*AI), Loc)) {
+ doesAlias = true;
+ break;
+ }
+
+ if (!doesAlias)
+ return NoModRef;
+ }
+
+ // If Loc is a constant memory location, the call definitely could not
+ // modify the memory location.
+ if ((Mask & Mod) && pointsToConstantMemory(Loc))
+ Mask = ModRefResult(Mask & ~Mod);
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Mask;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any mask we've managed to compute.
+ return ModRefResult(AA->getModRefInfo(CS, Loc) & Mask);
}
AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
- // If the stored address cannot alias the pointer in question, then the
- // pointer cannot be modified by the store.
- if (!alias(S->getOperand(1),
- getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
+AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+
+ // If CS1 or CS2 are readnone, they don't interact.
+ ModRefBehavior CS1B = getModRefBehavior(CS1);
+ if (CS1B == DoesNotAccessMemory) return NoModRef;
+
+ ModRefBehavior CS2B = getModRefBehavior(CS2);
+ if (CS2B == DoesNotAccessMemory) return NoModRef;
+
+ // If they both only read from memory, there is no dependence.
+ if (onlyReadsMemory(CS1B) && onlyReadsMemory(CS2B))
return NoModRef;
- // If the pointer is a pointer to constant memory, then it could not have been
- // modified by this store.
- return pointsToConstantMemory(P) ? NoModRef : Mod;
+ AliasAnalysis::ModRefResult Mask = ModRef;
+
+ // If CS1 only reads memory, the only dependence on CS2 can be
+ // from CS1 reading memory written by CS2.
+ if (onlyReadsMemory(CS1B))
+ Mask = ModRefResult(Mask & Ref);
+
+ // If CS2 only access memory through arguments, accumulate the mod/ref
+ // information from CS1's references to the memory referenced by
+ // CS2's arguments.
+ if (onlyAccessesArgPointees(CS2B)) {
+ AliasAnalysis::ModRefResult R = NoModRef;
+ if (doesAccessArgPointees(CS2B))
+ for (ImmutableCallSite::arg_iterator
+ I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) {
+ R = ModRefResult((R | getModRefInfo(CS1, *I, UnknownSize)) & Mask);
+ if (R == Mask)
+ break;
+ }
+ return R;
+ }
+
+ // If CS1 only accesses memory through arguments, check if CS2 references
+ // any of the memory referenced by CS1's arguments. If not, return NoModRef.
+ if (onlyAccessesArgPointees(CS1B)) {
+ AliasAnalysis::ModRefResult R = NoModRef;
+ if (doesAccessArgPointees(CS1B))
+ for (ImmutableCallSite::arg_iterator
+ I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I)
+ if (getModRefInfo(CS2, *I, UnknownSize) != NoModRef) {
+ R = Mask;
+ break;
+ }
+ if (R == NoModRef)
+ return R;
+ }
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Mask;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any mask we've managed to compute.
+ return ModRefResult(AA->getModRefInfo(CS1, CS2) & Mask);
}
AliasAnalysis::ModRefBehavior
-AliasAnalysis::getModRefBehavior(CallSite CS,
- std::vector<PointerAccessInfo> *Info) {
- if (CS.doesNotAccessMemory())
- // Can't do better than this.
- return DoesNotAccessMemory;
- ModRefBehavior MRB = getModRefBehavior(CS.getCalledFunction(), Info);
- if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
- return OnlyReadsMemory;
- return MRB;
+AliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+
+ ModRefBehavior Min = UnknownModRefBehavior;
+
+ // Call back into the alias analysis with the other form of getModRefBehavior
+ // to see if it can give a better response.
+ if (const Function *F = CS.getCalledFunction())
+ Min = getModRefBehavior(F);
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Min;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any result we've managed to compute.
+ return ModRefBehavior(AA->getModRefBehavior(CS) & Min);
}
AliasAnalysis::ModRefBehavior
-AliasAnalysis::getModRefBehavior(Function *F,
- std::vector<PointerAccessInfo> *Info) {
- if (F) {
- if (F->doesNotAccessMemory())
- // Can't do better than this.
- return DoesNotAccessMemory;
- if (F->onlyReadsMemory())
- return OnlyReadsMemory;
- if (unsigned id = F->getIntrinsicID())
- return getModRefBehavior(id);
- }
- return UnknownModRefBehavior;
+AliasAnalysis::getModRefBehavior(const Function *F) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->getModRefBehavior(F);
}
-AliasAnalysis::ModRefBehavior AliasAnalysis::getModRefBehavior(unsigned iid) {
-#define GET_INTRINSIC_MODREF_BEHAVIOR
-#include "llvm/Intrinsics.gen"
-#undef GET_INTRINSIC_MODREF_BEHAVIOR
+//===----------------------------------------------------------------------===//
+// AliasAnalysis non-virtual helper method implementation
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::Location AliasAnalysis::getLocation(const LoadInst *LI) {
+ return Location(LI->getPointerOperand(),
+ getTypeStoreSize(LI->getType()),
+ LI->getMetadata(LLVMContext::MD_tbaa));
}
+AliasAnalysis::Location AliasAnalysis::getLocation(const StoreInst *SI) {
+ return Location(SI->getPointerOperand(),
+ getTypeStoreSize(SI->getValueOperand()->getType()),
+ SI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location AliasAnalysis::getLocation(const VAArgInst *VI) {
+ return Location(VI->getPointerOperand(),
+ UnknownSize,
+ VI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+
+AliasAnalysis::Location
+AliasAnalysis::getLocationForSource(const MemTransferInst *MTI) {
+ uint64_t Size = UnknownSize;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(MTI->getLength()))
+ Size = C->getValue().getZExtValue();
+
+ // FIXME: Can memcpy/memmove have TBAA tags?
+ return Location(MTI->getRawSource(), Size, 0);
+}
+
+AliasAnalysis::Location
+AliasAnalysis::getLocationForDest(const MemIntrinsic *MTI) {
+ uint64_t Size = UnknownSize;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(MTI->getLength()))
+ Size = C->getValue().getZExtValue();
+
+ // FIXME: Can memcpy/memmove have TBAA tags?
+ return Location(MTI->getRawDest(), Size, 0);
+}
+
+
+
AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
- ModRefBehavior MRB = getModRefBehavior(CS);
- if (MRB == DoesNotAccessMemory)
+AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) {
+ // Be conservative in the face of volatile.
+ if (L->isVolatile())
+ return ModRef;
+
+ // If the load address doesn't alias the given address, it doesn't read
+ // or write the specified memory.
+ if (!alias(getLocation(L), Loc))
return NoModRef;
-
- ModRefResult Mask = ModRef;
- if (MRB == OnlyReadsMemory)
- Mask = Ref;
- else if (MRB == AliasAnalysis::AccessesArguments) {
- bool doesAlias = false;
- for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
- AI != AE; ++AI)
- if (!isNoAlias(*AI, ~0U, P, Size)) {
- doesAlias = true;
- break;
- }
- if (!doesAlias)
- return NoModRef;
- }
+ // Otherwise, a load just reads.
+ return Ref;
+}
- if (!AA) return Mask;
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
+ // Be conservative in the face of volatile.
+ if (S->isVolatile())
+ return ModRef;
- // If P points to a constant memory location, the call definitely could not
- // modify the memory location.
- if ((Mask & Mod) && AA->pointsToConstantMemory(P))
- Mask = ModRefResult(Mask & ~Mod);
+ // If the store address cannot alias the pointer in question, then the
+ // specified memory cannot be modified by the store.
+ if (!alias(getLocation(S), Loc))
+ return NoModRef;
+
+ // If the pointer is a pointer to constant memory, then it could not have been
+ // modified by this store.
+ if (pointsToConstantMemory(Loc))
+ return NoModRef;
- return ModRefResult(Mask & AA->getModRefInfo(CS, P, Size));
+ // Otherwise, a store just writes.
+ return Mod;
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(const VAArgInst *V, const Location &Loc) {
+ // If the va_arg address cannot alias the pointer in question, then the
+ // specified memory cannot be accessed by the va_arg.
+ if (!alias(getLocation(V), Loc))
+ return NoModRef;
+
+ // If the pointer is a pointer to constant memory, then it could not have been
+ // modified by this va_arg.
+ if (pointsToConstantMemory(Loc))
+ return NoModRef;
+
+ // Otherwise, a va_arg reads and writes.
+ return ModRef;
}
// AliasAnalysis destructor: DO NOT move this to the header file for
/// getTypeStoreSize - Return the TargetData store size for the given type,
/// if known, or a conservative value otherwise.
///
-unsigned AliasAnalysis::getTypeStoreSize(const Type *Ty) {
- return TD ? TD->getTypeStoreSize(Ty) : ~0u;
+uint64_t AliasAnalysis::getTypeStoreSize(const Type *Ty) {
+ return TD ? TD->getTypeStoreSize(Ty) : UnknownSize;
}
/// canBasicBlockModify - Return true if it is possible for execution of the
/// specified basic block to modify the value pointed to by Ptr.
///
bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB,
- const Value *Ptr, unsigned Size) {
- return canInstructionRangeModify(BB.front(), BB.back(), Ptr, Size);
+ const Location &Loc) {
+ return canInstructionRangeModify(BB.front(), BB.back(), Loc);
}
/// canInstructionRangeModify - Return true if it is possible for the execution
///
bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
const Instruction &I2,
- const Value *Ptr, unsigned Size) {
+ const Location &Loc) {
assert(I1.getParent() == I2.getParent() &&
"Instructions not in same basic block!");
- BasicBlock::iterator I = const_cast<Instruction*>(&I1);
- BasicBlock::iterator E = const_cast<Instruction*>(&I2);
+ BasicBlock::const_iterator I = &I1;
+ BasicBlock::const_iterator E = &I2;
++E; // Convert from inclusive to exclusive range.
for (; I != E; ++I) // Check every instruction in range
- if (getModRefInfo(I, const_cast<Value*>(Ptr), Size) & Mod)
+ if (getModRefInfo(I, Loc) & Mod)
return true;
return false;
}
/// function.
bool llvm::isNoAliasCall(const Value *V) {
if (isa<CallInst>(V) || isa<InvokeInst>(V))
- return CallSite(const_cast<Instruction*>(cast<Instruction>(V)))
+ return ImmutableCallSite(cast<Instruction>(V))
.paramHasAttr(0, Attribute::NoAlias);
return false;
}
/// identifiable object. This returns true for:
/// Global Variables and Functions (but not Global Aliases)
/// Allocas and Mallocs
-/// ByVal and NoAlias Arguments, if Interprocedural is false
-/// NoAlias returns, if Interprocedural is false
+/// ByVal and NoAlias Arguments
+/// NoAlias returns
///
-bool llvm::isIdentifiedObject(const Value *V, bool Interprocedural) {
+bool llvm::isIdentifiedObject(const Value *V) {
if (isa<AllocaInst>(V))
return true;
if (isa<GlobalValue>(V) && !isa<GlobalAlias>(V))
return true;
- if (!Interprocedural) {
- if (isNoAliasCall(V))
- return true;
- if (const Argument *A = dyn_cast<Argument>(V))
- return A->hasNoAliasAttr() || A->hasByValAttr();
- }
+ if (isNoAliasCall(V))
+ return true;
+ if (const Argument *A = dyn_cast<Argument>(V))
+ return A->hasNoAliasAttr() || A->hasByValAttr();
return false;
}
-
-// Because of the way .a files work, we must force the BasicAA implementation to
-// be pulled in if the AliasAnalysis classes are pulled in. Otherwise we run
-// the risk of AliasAnalysis being used, but the default implementation not
-// being linked into the tool that uses it.
-DEFINING_FILE_FOR(AliasAnalysis)
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