void visitFunction(Function &F);
void visitCallSite(CallSite CS);
- void visitMemoryReference(Instruction &I, Value *Ptr, unsigned Align,
+ void visitMemoryReference(Instruction &I, Value *Ptr,
+ unsigned Size, unsigned Align,
const Type *Ty, unsigned Flags);
void visitCallInst(CallInst &I);
Instruction &I = *CS.getInstruction();
Value *Callee = CS.getCalledValue();
- visitMemoryReference(I, Callee, 0, 0, MemRef::Callee);
+ visitMemoryReference(I, Callee, ~0u, 0, 0, MemRef::Callee);
if (Function *F = dyn_cast<Function>(findValue(Callee, /*OffsetOk=*/false))) {
Assert1(CS.getCallingConv() == F->getCallingConv(),
FT->getNumParams() == NumActualArgs,
"Undefined behavior: Call argument count mismatches callee "
"argument count", &I);
-
- // TODO: Check argument types (in case the callee was casted)
- // TODO: Check ABI-significant attributes.
-
- // TODO: Check noalias attribute.
-
- // TODO: Check sret attribute.
+ // Check argument types (in case the callee was casted) and attributes.
+ Function::arg_iterator PI = F->arg_begin(), PE = F->arg_end();
+ CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+ for (; AI != AE; ++AI) {
+ Value *Actual = *AI;
+ if (PI != PE) {
+ Argument *Formal = PI++;
+ Assert1(Formal->getType() == Actual->getType(),
+ "Undefined behavior: Call argument type mismatches "
+ "callee parameter type", &I);
+
+ // Check that noalias arguments don't alias other arguments. The
+ // AliasAnalysis API isn't expressive enough for what we really want
+ // to do. Known partial overlap is not distinguished from the case
+ // where nothing is known.
+ if (Formal->hasNoAliasAttr() && Actual->getType()->isPointerTy())
+ for (CallSite::arg_iterator BI = CS.arg_begin(); BI != AE; ++BI) {
+ Assert1(AI == BI ||
+ AA->alias(*AI, ~0u, *BI, ~0u) != AliasAnalysis::MustAlias,
+ "Unusual: noalias argument aliases another argument", &I);
+ }
+
+ // Check that an sret argument points to valid memory.
+ if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
+ const Type *Ty =
+ cast<PointerType>(Formal->getType())->getElementType();
+ visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
+ TD ? TD->getABITypeAlignment(Ty) : 0,
+ Ty, MemRef::Read | MemRef::Write);
+ }
+ }
+ }
}
if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
case Intrinsic::memcpy: {
MemCpyInst *MCI = cast<MemCpyInst>(&I);
- visitMemoryReference(I, MCI->getSource(), MCI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MCI->getDest(), ~0u, MCI->getAlignment(), 0,
MemRef::Write);
- visitMemoryReference(I, MCI->getDest(), MCI->getAlignment(), 0,
+ visitMemoryReference(I, MCI->getSource(), ~0u, MCI->getAlignment(), 0,
MemRef::Read);
// Check that the memcpy arguments don't overlap. The AliasAnalysis API
}
case Intrinsic::memmove: {
MemMoveInst *MMI = cast<MemMoveInst>(&I);
- visitMemoryReference(I, MMI->getSource(), MMI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MMI->getDest(), ~0u, MMI->getAlignment(), 0,
MemRef::Write);
- visitMemoryReference(I, MMI->getDest(), MMI->getAlignment(), 0,
+ visitMemoryReference(I, MMI->getSource(), ~0u, MMI->getAlignment(), 0,
MemRef::Read);
break;
}
case Intrinsic::memset: {
MemSetInst *MSI = cast<MemSetInst>(&I);
- visitMemoryReference(I, MSI->getDest(), MSI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MSI->getDest(), ~0u, MSI->getAlignment(), 0,
MemRef::Write);
break;
}
"Undefined behavior: va_start called in a non-varargs function",
&I);
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
case Intrinsic::vacopy:
- visitMemoryReference(I, CS.getArgument(0), 0, 0, MemRef::Write);
- visitMemoryReference(I, CS.getArgument(1), 0, 0, MemRef::Read);
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0, MemRef::Write);
+ visitMemoryReference(I, CS.getArgument(1), ~0u, 0, 0, MemRef::Read);
break;
case Intrinsic::vaend:
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
// Stackrestore doesn't read or write memory, but it sets the
// stack pointer, which the compiler may read from or write to
// at any time, so check it for both readability and writeability.
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
}
}
}
-// TODO: Add a length argument and check that the reference is in bounds
+// TODO: Check that the reference is in bounds.
void Lint::visitMemoryReference(Instruction &I,
- Value *Ptr, unsigned Align, const Type *Ty,
- unsigned Flags) {
+ Value *Ptr, unsigned Size, unsigned Align,
+ const Type *Ty, unsigned Flags) {
+ // If no memory is being referenced, it doesn't matter if the pointer
+ // is valid.
+ if (Size == 0)
+ return;
+
Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
Assert1(!isa<ConstantPointerNull>(UnderlyingObject),
"Undefined behavior: Null pointer dereference", &I);
Assert1(!isa<UndefValue>(UnderlyingObject),
"Undefined behavior: Undef pointer dereference", &I);
+ Assert1(!isa<ConstantInt>(UnderlyingObject) ||
+ !cast<ConstantInt>(UnderlyingObject)->isAllOnesValue(),
+ "Unusual: All-ones pointer dereference", &I);
+ Assert1(!isa<ConstantInt>(UnderlyingObject) ||
+ !cast<ConstantInt>(UnderlyingObject)->isOne(),
+ "Unusual: Address one pointer dereference", &I);
if (Flags & MemRef::Write) {
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(UnderlyingObject))
}
void Lint::visitLoadInst(LoadInst &I) {
- visitMemoryReference(I, I.getPointerOperand(), I.getAlignment(), I.getType(),
- MemRef::Read);
+ visitMemoryReference(I, I.getPointerOperand(),
+ AA->getTypeStoreSize(I.getType()), I.getAlignment(),
+ I.getType(), MemRef::Read);
}
void Lint::visitStoreInst(StoreInst &I) {
- visitMemoryReference(I, I.getPointerOperand(), I.getAlignment(),
- I.getOperand(0)->getType(), MemRef::Write);
+ visitMemoryReference(I, I.getPointerOperand(),
+ AA->getTypeStoreSize(I.getOperand(0)->getType()),
+ I.getAlignment(),
+ I.getOperand(0)->getType(), MemRef::Write);
}
void Lint::visitXor(BinaryOperator &I) {
}
void Lint::visitVAArgInst(VAArgInst &I) {
- visitMemoryReference(I, I.getOperand(0), 0, 0,
+ visitMemoryReference(I, I.getOperand(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
}
void Lint::visitIndirectBrInst(IndirectBrInst &I) {
- visitMemoryReference(I, I.getAddress(), 0, 0, MemRef::Branchee);
+ visitMemoryReference(I, I.getAddress(), ~0u, 0, 0, MemRef::Branchee);
}
void Lint::visitExtractElementInst(ExtractElementInst &I) {
// TODO: Look through sext or zext cast, when the result is known to
// be interpreted as signed or unsigned, respectively.
+ // TODO: Look through eliminable cast pairs.
// TODO: Look through calls with unique return values.
// TODO: Look through vector insert/extract/shuffle.
V = OffsetOk ? V->getUnderlyingObject() : V->stripPointerCasts();
if (LoadInst *L = dyn_cast<LoadInst>(V)) {
BasicBlock::iterator BBI = L;
BasicBlock *BB = L->getParent();
+ SmallPtrSet<BasicBlock *, 4> VisitedBlocks;
for (;;) {
+ if (!VisitedBlocks.insert(BB)) break;
if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
BB, BBI, 6, AA))
return findValueImpl(U, OffsetOk, Visited);
- BB = L->getParent()->getUniquePredecessor();
+ if (BBI != BB->begin()) break;
+ BB = BB->getUniquePredecessor();
if (!BB) break;
BBI = BB->end();
}
+ } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (Value *W = PN->hasConstantValue(DT))
+ return findValueImpl(W, OffsetOk, Visited);
} else if (CastInst *CI = dyn_cast<CastInst>(V)) {
if (CI->isNoopCast(TD ? TD->getIntPtrType(V->getContext()) :
Type::getInt64Ty(V->getContext())))
return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
- } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
- if (Value *W = PN->hasConstantValue(DT))
- return findValueImpl(W, OffsetOk, Visited);
} else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
Ex->idx_begin(),
Ex->idx_end()))
if (W != V)
return findValueImpl(W, OffsetOk, Visited);
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ // Same as above, but for ConstantExpr instead of Instruction.
+ if (Instruction::isCast(CE->getOpcode())) {
+ if (CastInst::isNoopCast(Instruction::CastOps(CE->getOpcode()),
+ CE->getOperand(0)->getType(),
+ CE->getType(),
+ TD ? TD->getIntPtrType(V->getContext()) :
+ Type::getInt64Ty(V->getContext())))
+ return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
+ } else if (CE->getOpcode() == Instruction::ExtractValue) {
+ const SmallVector<unsigned, 4> &Indices = CE->getIndices();
+ if (Value *W = FindInsertedValue(CE->getOperand(0),
+ Indices.begin(),
+ Indices.end()))
+ if (W != V)
+ return findValueImpl(W, OffsetOk, Visited);
+ }
}
// As a last resort, try SimplifyInstruction or constant folding.