#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(ImmutableCallSite CS,
- const Value *P, unsigned Size) {
- // Don't assert AA because BasicAA calls us in order to make use of the
- // logic here.
+ const Location &Loc) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
ModRefBehavior MRB = getModRefBehavior(CS);
if (MRB == DoesNotAccessMemory)
return NoModRef;
ModRefResult Mask = ModRef;
- if (MRB == OnlyReadsMemory)
+ if (onlyReadsMemory(MRB))
Mask = Ref;
- else if (MRB == AliasAnalysis::AccessesArguments) {
+
+ if (onlyAccessesArgPointees(MRB)) {
bool doesAlias = false;
- for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
- AI != AE; ++AI)
- if (!isNoAlias(*AI, ~0U, P, Size)) {
- doesAlias = true;
- break;
- }
+ 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 P points to a constant memory location, the call definitely could not
+ // If Loc is a constant memory location, the call definitely could not
// modify the memory location.
- if ((Mask & Mod) && pointsToConstantMemory(P))
+ if ((Mask & Mod) && pointsToConstantMemory(Loc))
Mask = ModRefResult(Mask & ~Mod);
- // If this is BasicAA, don't forward.
+ // 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, P, Size) & Mask);
+ return ModRefResult(AA->getModRefInfo(CS, Loc) & Mask);
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) {
- // Don't assert AA because BasicAA calls us in order to make use of the
- // logic here.
+ 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 (CS2B == DoesNotAccessMemory) return NoModRef;
// If they both only read from memory, there is no dependence.
- if (CS1B == OnlyReadsMemory && CS2B == OnlyReadsMemory)
+ if (onlyReadsMemory(CS1B) && onlyReadsMemory(CS2B))
return NoModRef;
AliasAnalysis::ModRefResult Mask = ModRef;
// If CS1 only reads memory, the only dependence on CS2 can be
// from CS1 reading memory written by CS2.
- if (CS1B == OnlyReadsMemory)
+ 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 (CS2B == AccessesArguments) {
+ if (onlyAccessesArgPointees(CS2B)) {
AliasAnalysis::ModRefResult R = NoModRef;
- 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;
- }
+ 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 (CS1B == AccessesArguments) {
+ if (onlyAccessesArgPointees(CS1B)) {
AliasAnalysis::ModRefResult R = NoModRef;
- 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 (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 BasicAA, don't forward.
+ // 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
AliasAnalysis::ModRefBehavior
AliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
- // Don't assert AA because BasicAA calls us in order to make use of the
- // logic here.
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
ModRefBehavior Min = UnknownModRefBehavior;
if (const Function *F = CS.getCalledFunction())
Min = getModRefBehavior(F);
- // If this is BasicAA, don't forward.
+ // 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 std::min(AA->getModRefBehavior(CS), Min);
+ return ModRefBehavior(AA->getModRefBehavior(CS) & Min);
}
AliasAnalysis::ModRefBehavior
return AA->getModRefBehavior(F);
}
-AliasAnalysis::DependenceResult
-AliasAnalysis::getDependence(const Instruction *First,
- DependenceQueryFlags FirstFlags,
- const Instruction *Second,
- DependenceQueryFlags SecondFlags) {
- assert(AA && "AA didn't call InitializeAliasAnalyais in its run method!");
- return AA->getDependence(First, FirstFlags, Second, SecondFlags);
-}
-
//===----------------------------------------------------------------------===//
// 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(const LoadInst *L, const Value *P, unsigned Size) {
+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(L->getOperand(0), getTypeStoreSize(L->getType()), P, Size))
+ if (!alias(getLocation(L), Loc))
return NoModRef;
// Otherwise, a load just reads.
}
AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(const StoreInst *S, const Value *P, unsigned Size) {
+AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
// Be conservative in the face of volatile.
if (S->isVolatile())
return ModRef;
// If the store address cannot alias the pointer in question, then the
// specified memory cannot be modified by the store.
- if (!alias(S->getOperand(1),
- getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
+ 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(P))
+ if (pointsToConstantMemory(Loc))
return NoModRef;
// Otherwise, a store just writes.
}
AliasAnalysis::ModRefResult
-AliasAnalysis::getModRefInfo(const VAArgInst *V, const Value *P, unsigned Size) {
+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(V->getOperand(0), UnknownSize, P, Size))
+ 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(P))
+ if (pointsToConstantMemory(Loc))
return NoModRef;
// Otherwise, a va_arg reads and writes.
return ModRef;
}
-AliasAnalysis::DependenceResult
-AliasAnalysis::getDependenceViaModRefInfo(const Instruction *First,
- DependenceQueryFlags FirstFlags,
- const Instruction *Second,
- DependenceQueryFlags SecondFlags) {
- if (const LoadInst *L = dyn_cast<LoadInst>(First)) {
- // Be over-conservative with volatile for now.
- if (L->isVolatile())
- return Unknown;
-
- // Forward this query to getModRefInfo.
- switch (getModRefInfo(Second,
- L->getPointerOperand(),
- getTypeStoreSize(L->getType()))) {
- case NoModRef:
- // Second doesn't reference First's memory, so they're independent.
- return Independent;
-
- case Ref:
- // Second only reads from the memory read from by First. If it
- // also writes to any other memory, be conservative.
- if (Second->mayWriteToMemory())
- return Unknown;
-
- // If it's loading the same size from the same address, we can
- // give a more precise result.
- if (const LoadInst *SecondL = dyn_cast<LoadInst>(Second)) {
- unsigned LSize = getTypeStoreSize(L->getType());
- unsigned SecondLSize = getTypeStoreSize(SecondL->getType());
- if (alias(L->getPointerOperand(), LSize,
- SecondL->getPointerOperand(), SecondLSize) ==
- MustAlias) {
- // If the loads are the same size, it's ReadThenRead.
- if (LSize == SecondLSize)
- return ReadThenRead;
-
- // If the second load is smaller, it's only ReadThenReadSome.
- if (LSize > SecondLSize)
- return ReadThenReadSome;
- }
- }
-
- // Otherwise it's just two loads.
- return Independent;
-
- case Mod:
- // Second only writes to the memory read from by First. If it
- // also reads from any other memory, be conservative.
- if (Second->mayReadFromMemory())
- return Unknown;
-
- // If it's storing the same size to the same address, we can
- // give a more precise result.
- if (const StoreInst *SecondS = dyn_cast<StoreInst>(Second)) {
- unsigned LSize = getTypeStoreSize(L->getType());
- unsigned SecondSSize = getTypeStoreSize(SecondS->getType());
- if (alias(L->getPointerOperand(), LSize,
- SecondS->getPointerOperand(), SecondSSize) ==
- MustAlias) {
- // If the load and the store are the same size, it's ReadThenWrite.
- if (LSize == SecondSSize)
- return ReadThenWrite;
- }
- }
-
- // Otherwise we don't know if it could be writing to other memory.
- return Unknown;
-
- case ModRef:
- // Second reads and writes to the memory read from by First.
- // We don't have a way to express that.
- return Unknown;
- }
-
- } else if (const StoreInst *S = dyn_cast<StoreInst>(First)) {
- // Be over-conservative with volatile for now.
- if (S->isVolatile())
- return Unknown;
-
- // Forward this query to getModRefInfo.
- switch (getModRefInfo(Second,
- S->getPointerOperand(),
- getTypeStoreSize(S->getValueOperand()->getType()))) {
- case NoModRef:
- // Second doesn't reference First's memory, so they're independent.
- return Independent;
-
- case Ref:
- // Second only reads from the memory written to by First. If it
- // also writes to any other memory, be conservative.
- if (Second->mayWriteToMemory())
- return Unknown;
-
- // If it's loading the same size from the same address, we can
- // give a more precise result.
- if (const LoadInst *SecondL = dyn_cast<LoadInst>(Second)) {
- unsigned SSize = getTypeStoreSize(S->getValueOperand()->getType());
- unsigned SecondLSize = getTypeStoreSize(SecondL->getType());
- if (alias(S->getPointerOperand(), SSize,
- SecondL->getPointerOperand(), SecondLSize) ==
- MustAlias) {
- // If the store and the load are the same size, it's WriteThenRead.
- if (SSize == SecondLSize)
- return WriteThenRead;
-
- // If the load is smaller, it's only WriteThenReadSome.
- if (SSize > SecondLSize)
- return WriteThenReadSome;
- }
- }
-
- // Otherwise we don't know if it could be reading from other memory.
- return Unknown;
-
- case Mod:
- // Second only writes to the memory written to by First. If it
- // also reads from any other memory, be conservative.
- if (Second->mayReadFromMemory())
- return Unknown;
-
- // If it's storing the same size to the same address, we can
- // give a more precise result.
- if (const StoreInst *SecondS = dyn_cast<StoreInst>(Second)) {
- unsigned SSize = getTypeStoreSize(S->getValueOperand()->getType());
- unsigned SecondSSize = getTypeStoreSize(SecondS->getType());
- if (alias(S->getPointerOperand(), SSize,
- SecondS->getPointerOperand(), SecondSSize) ==
- MustAlias) {
- // If the stores are the same size, it's WriteThenWrite.
- if (SSize == SecondSSize)
- return WriteThenWrite;
-
- // If the second store is larger, it's only WriteSomeThenWrite.
- if (SSize < SecondSSize)
- return WriteSomeThenWrite;
- }
- }
-
- // Otherwise we don't know if it could be writing to other memory.
- return Unknown;
-
- case ModRef:
- // Second reads and writes to the memory written to by First.
- // We don't have a way to express that.
- return Unknown;
- }
-
- } else if (const VAArgInst *V = dyn_cast<VAArgInst>(First)) {
- // Forward this query to getModRefInfo.
- if (getModRefInfo(Second, V->getOperand(0), UnknownSize) == NoModRef)
- // Second doesn't reference First's memory, so they're independent.
- return Independent;
-
- } else if (ImmutableCallSite FirstCS = cast<Value>(First)) {
- // If both instructions are calls/invokes we can use the two-callsite
- // form of getModRefInfo.
- if (ImmutableCallSite SecondCS = cast<Value>(Second))
- // getModRefInfo's arguments are backwards from intuition.
- switch (getModRefInfo(SecondCS, FirstCS)) {
- case NoModRef:
- // Second doesn't reference First's memory, so they're independent.
- return Independent;
-
- case Ref:
- // If they're both read-only, there's no dependence.
- if (FirstCS.onlyReadsMemory() && SecondCS.onlyReadsMemory())
- return Independent;
-
- // Otherwise it's not obvious what we can do here.
- return Unknown;
-
- case Mod:
- // It's not obvious what we can do here.
- return Unknown;
-
- case ModRef:
- // I know, right?
- return Unknown;
- }
- }
-
- // For anything else, be conservative.
- return Unknown;
-}
-
-AliasAnalysis::ModRefBehavior
-AliasAnalysis::getIntrinsicModRefBehavior(unsigned iid) {
-#define GET_INTRINSIC_MODREF_BEHAVIOR
-#include "llvm/Intrinsics.gen"
-#undef GET_INTRINSIC_MODREF_BEHAVIOR
-}
-
// AliasAnalysis destructor: DO NOT move this to the header file for
// AliasAnalysis or else clients of the AliasAnalysis class may not depend on
// the AliasAnalysis.o file in the current .a file, causing alias analysis
/// 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::const_iterator I = &I1;
++E; // Convert from inclusive to exclusive range.
for (; I != E; ++I) // Check every instruction in range
- if (getModRefInfo(I, Ptr, Size) & Mod)
+ if (getModRefInfo(I, Loc) & Mod)
return true;
return false;
}
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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