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path: root/lib/Transforms/Utils/SimplifyLibCalls.cpp
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-rw-r--r--lib/Transforms/Utils/SimplifyLibCalls.cpp51
1 files changed, 49 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index bd28ec35273..032a2fdfcf6 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -183,14 +183,30 @@ struct StrCpyChkOpt : public InstFortifiedLibCallOptimization {
FT->getParamType(2) != TD->getIntPtrType(Context))
return 0;
+ Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
+ if (Dst == Src) // __strcpy_chk(x,x) -> x
+ return Src;
+
// If a) we don't have any length information, or b) we know this will
// fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
// st[rp]cpy_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 (isFoldable(2, 1, true)) {
- Value *Ret = EmitStrCpy(CI->getArgOperand(0), CI->getArgOperand(1), B, TD,
- TLI, Name.substr(2, 6));
+ Value *Ret = EmitStrCpy(Dst, Src, B, TD, TLI, Name.substr(2, 6));
+ return Ret;
+ } else {
+ // Maybe we can stil fold __strcpy_chk to __memcpy_chk.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return 0;
+
+ // This optimization require DataLayout.
+ if (!TD) return 0;
+
+ Value *Ret =
+ EmitMemCpyChk(Dst, Src,
+ ConstantInt::get(TD->getIntPtrType(Context), Len),
+ CI->getArgOperand(2), B, TD, TLI);
return Ret;
}
return 0;
@@ -497,6 +513,35 @@ struct StrNCmpOpt : public LibCallOptimization {
}
};
+struct StrCpyOpt : public LibCallOptimization {
+ virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Verify the "strcpy" function prototype.
+ FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != B.getInt8PtrTy())
+ return 0;
+
+ Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
+ if (Dst == Src) // strcpy(x,x) -> x
+ return Src;
+
+ // These optimizations require DataLayout.
+ if (!TD) return 0;
+
+ // See if we can get the length of the input string.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return 0;
+
+ // We have enough information to now generate the memcpy call to do the
+ // copy for us. Make a memcpy to copy the nul byte with align = 1.
+ B.CreateMemCpy(Dst, Src,
+ ConstantInt::get(TD->getIntPtrType(*Context), Len), 1);
+ return Dst;
+ }
+};
+
} // End anonymous namespace.
namespace llvm {
@@ -520,6 +565,7 @@ class LibCallSimplifierImpl {
StrRChrOpt StrRChr;
StrCmpOpt StrCmp;
StrNCmpOpt StrNCmp;
+ StrCpyOpt StrCpy;
void initOptimizations();
public:
@@ -548,6 +594,7 @@ void LibCallSimplifierImpl::initOptimizations() {
Optimizations["strncat"] = &StrNCat;
Optimizations["strchr"] = &StrChr;
Optimizations["strrchr"] = &StrRChr;
+ Optimizations["strcpy"] = &StrCpy;
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {