struct StrCpyChkOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
- // These optimizations require TargetData.
- if (!TD) return 0;
-
const FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!isa<PointerType>(FT->getParamType(0)) ||
- !isa<PointerType>(FT->getParamType(1)) ||
- !isa<IntegerType>(FT->getParamType(2)))
+ !isa<PointerType>(FT->getParamType(1)))
return 0;
ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(3));
if (!SizeCI)
return 0;
- // We don't have any length information, just lower to a plain strcpy.
- if (SizeCI->isAllOnesValue())
+ // If a) we don't have any length information, or b) we know this will
+ // fit then just lower to a plain strcpy. Otherwise we'll keep our
+ // strcpy_chk call which may fail at runtime if the size is too long.
+ // TODO: It might be nice to get a maximum length out of the possible
+ // string lengths for varying.
+ if (SizeCI->isAllOnesValue() ||
+ SizeCI->getZExtValue() >= GetStringLength(CI->getOperand(2)))
return EmitStrCpy(CI->getOperand(1), CI->getOperand(2), B);
return 0;