Teach simplify libcall to transform __strcpy_chk to __memcpy_chk to enable optimizations down stream.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99282 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 5 deletions

diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 22f3628cf7..058cd3c561 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -49,10 +49,13 @@ protected:
   Function *Caller;
   const TargetData *TD;
   LLVMContext* Context;
+  bool OptChkCall;  // True if it's optimizing a *_chk libcall.
 public:
-  LibCallOptimization() { }
+  LibCallOptimization() : OptChkCall(false) { }
   virtual ~LibCallOptimization() {}
 
+  void setOptChkCall(bool c) { OptChkCall = c; }
+
   /// CallOptimizer - This pure virtual method is implemented by base classes to
   /// do various optimizations.  If this returns null then no transformation was
   /// performed.  If it returns CI, then it transformed the call and CI is to be
@@ -352,8 +355,10 @@ struct StrNCmpOpt : public LibCallOptimization {
 struct StrCpyOpt : public LibCallOptimization {
   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
     // Verify the "strcpy" function prototype.
+    unsigned NumParams = OptChkCall ? 3 : 2;
     const FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+    if (FT->getNumParams() != NumParams ||
+        FT->getReturnType() != FT->getParamType(0) ||
         FT->getParamType(0) != FT->getParamType(1) ||
         FT->getParamType(0) != Type::getInt8PtrTy(*Context))
       return 0;
@@ -371,8 +376,13 @@ struct StrCpyOpt : public LibCallOptimization {
 
     // We have enough information to now generate the memcpy call to do the
     // concatenation for us.  Make a memcpy to copy the nul byte with align = 1.
-    EmitMemCpy(Dst, Src,
-               ConstantInt::get(TD->getIntPtrType(*Context), Len), 1, B, TD);
+    if (OptChkCall)
+      EmitMemCpyChk(Dst, Src,
+                    ConstantInt::get(TD->getIntPtrType(*Context), Len),
+                    CI->getOperand(3), B, TD);
+    else
+      EmitMemCpy(Dst, Src,
+                 ConstantInt::get(TD->getIntPtrType(*Context), Len), 1, B, TD);
     return Dst;
   }
 };
@@ -1162,7 +1172,8 @@ namespace {
     StringMap<LibCallOptimization*> Optimizations;
     // String and Memory LibCall Optimizations
     StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrCmpOpt StrCmp;
-    StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrNCpyOpt StrNCpy; StrLenOpt StrLen;
+    StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
+    StrNCpyOpt StrNCpy; StrLenOpt StrLen;
     StrToOpt StrTo; StrStrOpt StrStr;
     MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
     // Math Library Optimizations
@@ -1228,6 +1239,10 @@ void SimplifyLibCalls::InitOptimizations() {
   Optimizations["memmove"] = &MemMove;
   Optimizations["memset"] = &MemSet;
 
+  // _chk variants of String and Memory LibCall Optimizations.
+  StrCpyChk.setOptChkCall(true);
+  Optimizations["__strcpy_chk"] = &StrCpyChk;
+
   // Math Library Optimizations
   Optimizations["powf"] = &Pow;
   Optimizations["pow"] = &Pow;