[llvm-commits] [llvm] r99282 - in /llvm/trunk: lib/Transforms/Scalar/SimplifyLibCalls.cpp lib/Transforms/Utils/BuildLibCalls.cpp test/Transforms/SimplifyLibCalls/StrCpy.ll

Chris Lattner clattner at apple.com
Tue Mar 23 14:42:40 PDT 2010


On Mar 23, 2010, at 8:48 AM, Evan Cheng wrote:

> Author: evancheng
> Date: Tue Mar 23 10:48:04 2010
> New Revision: 99282
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=99282&view=rev
> Log:
> Teach simplify libcall to transform __strcpy_chk to __memcpy_chk to enable optimizations down stream.

Hi Evan,

> +++ llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp Tue Mar 23 10:48:04 2010
> @@ -49,10 +49,13 @@
>   Function *Caller;
>   const TargetData *TD;
>   LLVMContext* Context;
> +  bool OptChkCall;  // True if it's optimizing a *_chk libcall.

This is state is not appropriate to add to LibCallOptimization.  If you want to do this, it should be added as a constructor option to StrCpyOpt.

-Chris

> 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 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 @@
> 
>     // 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 @@
>     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 @@
>   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;
> 
> Modified: llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp?rev=99282&r1=99281&r2=99282&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp Tue Mar 23 10:48:04 2010
> @@ -108,7 +108,7 @@
> 
> 
> /// EmitMemCpy - Emit a call to the memcpy function to the builder.  This always
> -/// expects that the size has type 'intptr_t' and Dst/Src are pointers.
> +/// expects that Len has type 'intptr_t' and Dst/Src are pointers.
> Value *llvm::EmitMemCpy(Value *Dst, Value *Src, Value *Len,
>                         unsigned Align, IRBuilder<> &B, const TargetData *TD) {
>   Module *M = B.GetInsertBlock()->getParent()->getParent();
> @@ -120,6 +120,30 @@
>                        ConstantInt::get(B.getInt32Ty(), Align));
> }
> 
> +/// EmitMemCpyChk - Emit a call to the __memcpy_chk function to the builder.
> +/// This expects that the Len and ObjSize have type 'intptr_t' and Dst/Src
> +/// are pointers.
> +Value *llvm::EmitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
> +                           IRBuilder<> &B, const TargetData *TD) {
> +  Module *M = B.GetInsertBlock()->getParent()->getParent();
> +  AttributeWithIndex AWI;
> +  AWI = AttributeWithIndex::get(~0u, Attribute::NoUnwind);
> +  LLVMContext &Context = B.GetInsertBlock()->getContext();
> +  Value *MemCpy = M->getOrInsertFunction("__memcpy_chk",
> +                                         AttrListPtr::get(&AWI, 1),
> +                                         B.getInt8PtrTy(),
> +                                         B.getInt8PtrTy(),
> +                                         B.getInt8PtrTy(),
> +                                         TD->getIntPtrType(Context),
> +                                         TD->getIntPtrType(Context), NULL);
> +  Dst = CastToCStr(Dst, B);
> +  Src = CastToCStr(Src, B);
> +  CallInst *CI = B.CreateCall4(MemCpy, Dst, Src, Len, ObjSize);
> +  if (const Function *F = dyn_cast<Function>(MemCpy->stripPointerCasts()))
> +    CI->setCallingConv(F->getCallingConv());
> +  return CI;
> +}
> +
> /// EmitMemMove - Emit a call to the memmove function to the builder.  This
> /// always expects that the size has type 'intptr_t' and Dst/Src are pointers.
> Value *llvm::EmitMemMove(Value *Dst, Value *Src, Value *Len,
> 
> Modified: llvm/trunk/test/Transforms/SimplifyLibCalls/StrCpy.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyLibCalls/StrCpy.ll?rev=99282&r1=99281&r2=99282&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/SimplifyLibCalls/StrCpy.ll (original)
> +++ llvm/trunk/test/Transforms/SimplifyLibCalls/StrCpy.ll Tue Mar 23 10:48:04 2010
> @@ -1,30 +1,37 @@
> ; Test that the StrCpyOptimizer works correctly
> -; RUN: opt < %s -simplify-libcalls -S | \
> -; RUN:   not grep {call.*strcpy}
> +; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
> 
> ; This transformation requires the pointer size, as it assumes that size_t is
> ; the size of a pointer.
> -target datalayout = "-p:64:64:64"
> +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
> 
> - at hello = constant [6 x i8] c"hello\00"		; <[6 x i8]*> [#uses=1]
> - at null = constant [1 x i8] zeroinitializer		; <[1 x i8]*> [#uses=1]
> - at null_hello = constant [7 x i8] c"\00hello\00"		; <[7 x i8]*> [#uses=1]
> + at hello = constant [6 x i8] c"hello\00"
> 
> declare i8* @strcpy(i8*, i8*)
> 
> -declare i32 @puts(i8*)
> +declare i8* @__strcpy_chk(i8*, i8*, i32) nounwind
> 
> -define i32 @main() {
> -	%target = alloca [1024 x i8]		; <[1024 x i8]*> [#uses=1]
> -	%arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0		; <i8*> [#uses=2]
> -	store i8 0, i8* %arg1
> -	%arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0		; <i8*> [#uses=1]
> -	%rslt1 = call i8* @strcpy( i8* %arg1, i8* %arg2 )		; <i8*> [#uses=1]
> -	%arg3 = getelementptr [1 x i8]* @null, i32 0, i32 0		; <i8*> [#uses=1]
> -	%rslt2 = call i8* @strcpy( i8* %rslt1, i8* %arg3 )		; <i8*> [#uses=1]
> -	%arg4 = getelementptr [7 x i8]* @null_hello, i32 0, i32 0		; <i8*> [#uses=1]
> -	%rslt3 = call i8* @strcpy( i8* %rslt2, i8* %arg4 )		; <i8*> [#uses=1]
> -	call i32 @puts( i8* %rslt3 )		; <i32>:1 [#uses=0]
> -	ret i32 0
> +declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly
> +
> +; rdar://6839935
> +
> +define i32 @t1() {
> +; CHECK: @t1
> +  %target = alloca [1024 x i8]
> +  %arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
> +  %arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
> +  %rslt1 = call i8* @strcpy( i8* %arg1, i8* %arg2 )
> +; CHECK: @llvm.memcpy.i32
> +  ret i32 0
> }
> 
> +define i32 @t2() {
> +; CHECK: @t2
> +  %target = alloca [1024 x i8]
> +  %arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
> +  %arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
> +  %tmp1 = call i32 @llvm.objectsize.i32(i8* %arg1, i1 false)
> +  %rslt1 = call i8* @__strcpy_chk(i8* %arg1, i8* %arg2, i32 %tmp1)
> +; CHECK: @__memcpy_chk
> +  ret i32 0
> +}
> 
> 
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