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fix rdar://8251384, another case where we could access beyond the 

end of a struct.  This improves the case when the struct being passed
contains 3 floats, either due to a struct or array of 3 things.  Before
we'd generate this IR for the testcase:

define float @bar(double %X.coerce0, double %X.coerce1) nounwind {
entry:
  %X = alloca %struct.foof, align 8               ; <%struct.foof*> [#uses=2]
  %0 = bitcast %struct.foof* %X to %1*            ; <%1*> [#uses=2]
  %1 = getelementptr %1* %0, i32 0, i32 0         ; <double*> [#uses=1]
  store double %X.coerce0, double* %1
  %2 = getelementptr %1* %0, i32 0, i32 1         ; <double*> [#uses=1]
  store double %X.coerce1, double* %2
  %tmp = getelementptr inbounds %struct.foof* %X, i32 0, i32 2 ; <float*> [#uses=1]
  %tmp1 = load float* %tmp                        ; <float> [#uses=1]
  ret float %tmp1
}

which compiled (with optimization) to:

_bar:                                   ## @bar
## BB#0:                                ## %entry
	movd	%xmm1, %rax
	movd	%eax, %xmm0
	ret

Now we produce:

define float @bar(double %X.coerce0, float %X.coerce1) nounwind {
entry:
  %X = alloca %struct.foof, align 8               ; <%struct.foof*> [#uses=2]
  %0 = bitcast %struct.foof* %X to %0*            ; <%0*> [#uses=2]
  %1 = getelementptr %0* %0, i32 0, i32 0         ; <double*> [#uses=1]
  store double %X.coerce0, double* %1
  %2 = getelementptr %0* %0, i32 0, i32 1         ; <float*> [#uses=1]
  store float %X.coerce1, float* %2
  %tmp = getelementptr inbounds %struct.foof* %X, i32 0, i32 2 ; <float*> [#uses=1]
  %tmp1 = load float* %tmp                        ; <float> [#uses=1]
  ret float %tmp1
}

and:

_bar:                                   ## @bar
## BB#0:                                ## %entry
	movaps	%xmm1, %xmm0
	ret

llvm-svn: 109776
This commit is contained in:
Chris Lattner 2010-07-29 18:13:09 +00:00
parent be2bb0d337
commit 7f4b81af7a
2 changed files with 38 additions and 21 deletions
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49
clang/lib/CodeGen/TargetInfo.cpp
View File

@ -719,7 +719,8 @@ class X86_64ABIInfo : public ABIInfo {
const llvm::Type *Get16ByteVectorType(QualType Ty) const;
const llvm::Type *GetSSETypeAtOffset(const llvm::Type *IRType,
unsigned IROffset) const;
unsigned IROffset, QualType SourceTy,
unsigned SourceOffset) const;
const llvm::Type *GetINTEGERTypeAtOffset(const llvm::Type *IRType,
unsigned IROffset, QualType SourceTy,
unsigned SourceOffset) const;
@ -1211,21 +1212,6 @@ const llvm::Type *X86_64ABIInfo::Get16ByteVectorType(QualType Ty) const {
return llvm::VectorType::get(llvm::Type::getDoubleTy(getVMContext()), 2);
}
/// GetSSETypeAtOffset - Return a type that will be passed by the backend in the
/// low 8 bytes of an XMM register, corresponding to the SSE class.
const llvm::Type *X86_64ABIInfo::GetSSETypeAtOffset(const llvm::Type *IRType,
unsigned IROffset) const {
// The only two choices we have are either double or <2 x float>.
// FIXME: <2 x float> doesn't pass as one XMM register yet. Don't enable this
// code until it does.
return llvm::Type::getDoubleTy(getVMContext());
}
/// BitsContainNoUserData - Return true if the specified [start,end) bit range
/// is known to either be off the end of the specified type or being in
/// alignment padding. The user type specified is known to be at most 128 bits
@ -1311,6 +1297,27 @@ static bool BitsContainNoUserData(QualType Ty, unsigned StartBit,
return false;
}
/// GetSSETypeAtOffset - Return a type that will be passed by the backend in the
/// low 8 bytes of an XMM register, corresponding to the SSE class.
const llvm::Type *X86_64ABIInfo::
GetSSETypeAtOffset(const llvm::Type *IRType, unsigned IROffset,
QualType SourceTy, unsigned SourceOffset) const {
// The only two choices we have are either double, <2 x float>, or float. We
// pass as float if the last 4 bytes is just padding. This happens for
// structs that contain 3 floats.
if (BitsContainNoUserData(SourceTy, SourceOffset*8+32,
SourceOffset*8+64, getContext()))
return llvm::Type::getFloatTy(getVMContext());
// FIXME: <2 x float> doesn't pass as one XMM register yet. Don't enable this
// code until it does.
//return llvm::VectorType::get(llvm::Type::getFloatTy(getVMContext()), 2);
return llvm::Type::getDoubleTy(getVMContext());
}
/// GetINTEGERTypeAtOffset - The ABI specifies that a value should be passed in
/// an 8-byte GPR. This means that we either have a scalar or we are talking
/// about the high or low part of an up-to-16-byte struct. This routine picks
@ -1420,7 +1427,7 @@ classifyReturnType(QualType RetTy) const {
// AMD64-ABI 3.2.3p4: Rule 4. If the class is SSE, the next
// available SSE register of the sequence %xmm0, %xmm1 is used.
case SSE:
ResType = GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 0);
ResType = GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 0, RetTy, 0);
break;
// AMD64-ABI 3.2.3p4: Rule 6. If the class is X87, the value is
@ -1460,7 +1467,7 @@ classifyReturnType(QualType RetTy) const {
}
case SSE: {
const llvm::Type *HiType =
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 8);
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 8, RetTy, 8);
ResType = llvm::StructType::get(getVMContext(), ResType, HiType,NULL);
break;
}
@ -1483,7 +1490,7 @@ classifyReturnType(QualType RetTy) const {
// extra bits in an SSE reg.
if (Lo != X87) {
const llvm::Type *HiType =
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 8);
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(RetTy), 8, RetTy, 8);
ResType = llvm::StructType::get(getVMContext(), ResType, HiType, NULL);
}
break;
@ -1539,7 +1546,7 @@ ABIArgInfo X86_64ABIInfo::classifyArgumentType(QualType Ty, unsigned &neededInt,
// order from %xmm0 to %xmm7.
case SSE:
++neededSSE;
ResType = GetSSETypeAtOffset(CGT.ConvertTypeRecursive(Ty), 0);
ResType = GetSSETypeAtOffset(CGT.ConvertTypeRecursive(Ty), 0, Ty, 0);
break;
}
@ -1569,7 +1576,7 @@ ABIArgInfo X86_64ABIInfo::classifyArgumentType(QualType Ty, unsigned &neededInt,
case X87Up:
case SSE: {
const llvm::Type *HiType =
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(Ty), 8);
GetSSETypeAtOffset(CGT.ConvertTypeRecursive(Ty), 8, Ty, 8);
ResType = llvm::StructType::get(getVMContext(), ResType, HiType, NULL);
++neededSSE;
break;

10
clang/test/CodeGen/x86_64-arguments.c
View File

@ -210,3 +210,13 @@ struct S0 { char f0[8]; char f2; char f3; char f4; };
void f30(struct S0 p_4) {
// CHECK: define void @f30(i64 %p_4.coerce0, i24 %p_4.coerce1)
}
// Pass the third element as a float when followed by tail padding.
// rdar://8251384
struct f31foo { float a, b, c; };
float f31(struct f31foo X) {
// CHECK: define float @f31(double %X.coerce0, float %X.coerce1)
return X.c;
}