Author: baldrick
Date: Mon Feb 4 11:21:32 2008
New Revision: 46710
URL: http://llvm.org/viewvc/llvm-project?rev=46710&view=rev
Log:
Fix PR1942, hopefully correctly. This is the same
as the previous fix except that a temporary buffer
is not used if CALL_EXPR_RETURN_SLOT_OPT is true.
This flag is sometimes used to indicate front-end
semantic requirements and cannot be ignored. Also,
unlike in the previous fixes, keep the mucking around
with RESULT_DECL in EmitMODIFY_EXPR, only tweak it to
match the logic in expand_assignment (expr.c). While
there I introduced some symbolic names, tweaked some
existing names and cleaned up trailing whitespace.
Modified:
llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp
llvm-gcc-4.2/trunk/gcc/llvm-internal.h
Modified: llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp?rev=46710&r1=46709&r2=46710&view=diff
==============================================================================
--- llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp (original)
+++ llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp Mon Feb 4 11:21:32 2008
@@ -2308,6 +2308,7 @@
CallingConv::ID &CallingConvention;
LLVMBuilder &Builder;
const MemRef *DestLoc;
+ MemRef BufLoc;
std::vector<Value*> LocStack;
FunctionCallArgumentConversion(tree exp, SmallVector<Value*, 16> &ops,
@@ -2339,7 +2340,19 @@
assert(LocStack.size() == 1 && "Imbalance!");
LocStack.clear();
}
-
+
+ // CopyOutResult - If the (aggregate) return result was redirected to a
+ // buffer, copy it to the final destination.
+ void CopyOutResult(tree result_type) {
+ if (BufLoc.Ptr && DestLoc) {
+ // A buffer was used for the aggregate return result. Copy it out now.
+ assert(ConvertType(result_type) ==
+ cast<PointerType>(BufLoc.Ptr->getType())->getElementType() &&
+ "Inconsistent result types!");
+ TheTreeToLLVM->EmitAggregateCopy(*DestLoc, BufLoc, result_type);
+ }
+ }
+
/// HandleScalarResult - This callback is invoked if the function returns a
/// simple scalar result value.
void HandleScalarResult(const Type *RetTy) {
@@ -2354,27 +2367,34 @@
void HandleAggregateResultAsScalar(const Type *ScalarTy) {
// There is nothing to do here.
}
-
+
/// HandleAggregateShadowArgument - This callback is invoked if the
function
/// returns an aggregate value by using a "shadow" first parameter. If
/// RetPtr is set to true, the pointer argument itself is returned from the
/// function.
void HandleAggregateShadowArgument(const PointerType *PtrArgTy,
bool RetPtr) {
- // We need to pass a buffer to return into. If the caller uses the
- // result, DestLoc will be set. If it ignores it, it could be unset,
- // in which case we need to create a dummy buffer.
- // FIXME: The alignment and volatility of the buffer are being ignored!
- Value *DestPtr;
+ // We need to pass memory to write the return value into.
+ // FIXME: alignment and volatility are being ignored!
+ assert(!DestLoc || PtrArgTy == DestLoc->Ptr->getType());
+
if (DestLoc == 0) {
- DestPtr = TheTreeToLLVM->CreateTemporary(PtrArgTy->getElementType());
+ // The result is unused, but still needs to be stored somewhere.
+ Value *Buf =
TheTreeToLLVM->CreateTemporary(PtrArgTy->getElementType());
+ CallOperands.push_back(Buf);
+ } else if (CALL_EXPR_RETURN_SLOT_OPT(CallExpression)) {
+ // Letting the call write directly to the final destination is safe and
+ // may be required. Do not use a buffer.
+ CallOperands.push_back(DestLoc->Ptr);
} else {
- DestPtr = DestLoc->Ptr;
- assert(PtrArgTy == DestPtr->getType());
+ // Letting the call write directly to the final destination may not be
+ // safe (eg: if DestLoc aliases a parameter) and is not required - pass
+ // a buffer and copy it to DestLoc after the call.
+ BufLoc = TheTreeToLLVM->CreateTempLoc(PtrArgTy->getElementType());
+ CallOperands.push_back(BufLoc.Ptr);
}
- CallOperands.push_back(DestPtr);
}
-
+
void HandleScalarArgument(const llvm::Type *LLVMTy, tree type) {
assert(!LocStack.empty());
Value *Loc = LocStack.back();
@@ -2543,7 +2563,9 @@
cast<InvokeInst>(Call)->setParamAttrs(PAL);
EmitBlock(NextBlock);
}
-
+
+ Client.CopyOutResult(TREE_TYPE(exp));
+
if (Call->getType() == Type::VoidTy)
return 0;
@@ -2626,50 +2648,48 @@
/// EmitMODIFY_EXPR - Note that MODIFY_EXPRs are rvalues only!
///
Value *TreeToLLVM::EmitMODIFY_EXPR(tree exp, const MemRef *DestLoc) {
+ tree lhs = TREE_OPERAND (exp, 0);
+ tree rhs = TREE_OPERAND (exp, 1);
+
// If this is the definition of an SSA variable, set its DECL_LLVM to the
// RHS.
- bool Op0Signed = !TYPE_UNSIGNED(TREE_TYPE(TREE_OPERAND(exp, 0)));
- bool Op1Signed = !TYPE_UNSIGNED(TREE_TYPE(TREE_OPERAND(exp, 1)));
- if (isGCC_SSA_Temporary(TREE_OPERAND(exp, 0))) {
+ bool LHSSigned = !TYPE_UNSIGNED(TREE_TYPE(lhs));
+ bool RHSSigned = !TYPE_UNSIGNED(TREE_TYPE(rhs));
+ if (isGCC_SSA_Temporary(lhs)) {
// If DECL_LLVM is already set, this is a multiply defined GCC temporary.
- if (DECL_LLVM_SET_P(TREE_OPERAND(exp, 0))) {
- HandleMultiplyDefinedGCCTemp(TREE_OPERAND(exp, 0));
+ if (DECL_LLVM_SET_P(lhs)) {
+ HandleMultiplyDefinedGCCTemp(lhs);
return EmitMODIFY_EXPR(exp, DestLoc);
}
-
- Value *RHS = Emit(TREE_OPERAND(exp, 1), 0);
- RHS = CastToAnyType(RHS, Op1Signed,
- ConvertType(TREE_TYPE(TREE_OPERAND(exp, 0))),
- Op0Signed);
- SET_DECL_LLVM(TREE_OPERAND(exp, 0), RHS);
+
+ Value *RHS = Emit(rhs, 0);
+ RHS = CastToAnyType(RHS, RHSSigned, ConvertType(TREE_TYPE(lhs)),
LHSSigned);
+ SET_DECL_LLVM(lhs, RHS);
return RHS;
- } else if (TREE_CODE(TREE_OPERAND(exp, 0)) == VAR_DECL &&
- DECL_REGISTER(TREE_OPERAND(exp, 0)) &&
- TREE_STATIC(TREE_OPERAND(exp, 0))) {
+ } else if (TREE_CODE(lhs) == VAR_DECL && DECL_REGISTER(lhs) &&
+ TREE_STATIC(lhs)) {
// If this is a store to a register variable, EmitLV can't handle the dest
// (there is no l-value of a register variable). Emit an inline asm node
// that copies the value into the specified register.
- Value *RHS = Emit(TREE_OPERAND(exp, 1), 0);
- RHS = CastToAnyType(RHS, Op1Signed,
- ConvertType(TREE_TYPE(TREE_OPERAND(exp, 0))),
- Op0Signed);
- EmitModifyOfRegisterVariable(TREE_OPERAND(exp, 0), RHS);
+ Value *RHS = Emit(rhs, 0);
+ RHS = CastToAnyType(RHS, RHSSigned, ConvertType(TREE_TYPE(lhs)),
LHSSigned);
+ EmitModifyOfRegisterVariable(lhs, RHS);
return RHS;
}
-
- LValue LV = EmitLV(TREE_OPERAND(exp, 0));
- bool isVolatile = TREE_THIS_VOLATILE(TREE_OPERAND(exp, 0));
- unsigned Alignment = expr_align(TREE_OPERAND(exp, 0)) / 8;
+
+ LValue LV = EmitLV(lhs);
+ bool isVolatile = TREE_THIS_VOLATILE(lhs);
+ unsigned Alignment = expr_align(lhs) / 8;
if (!LV.isBitfield()) {
- const Type *ValTy = ConvertType(TREE_TYPE(TREE_OPERAND(exp, 1)));
+ const Type *ValTy = ConvertType(TREE_TYPE(rhs));
if (ValTy->isFirstClassType()) {
// Non-bitfield, scalar value. Just emit a store.
- Value *RHS = Emit(TREE_OPERAND(exp, 1), 0);
+ Value *RHS = Emit(rhs, 0);
// Convert RHS to the right type if we can, otherwise convert the
pointer.
const PointerType *PT = cast<PointerType>(LV.Ptr->getType());
if (PT->getElementType()->canLosslesslyBitCastTo(RHS->getType()))
- RHS = CastToAnyType(RHS, Op1Signed, PT->getElementType(), Op0Signed);
+ RHS = CastToAnyType(RHS, RHSSigned, PT->getElementType(), LHSSigned);
else
LV.Ptr = BitCastToType(LV.Ptr, PointerType::getUnqual(RHS->getType()));
StoreInst *SI = Builder.CreateStore(RHS, LV.Ptr, isVolatile);
@@ -2680,27 +2700,27 @@
// Non-bitfield aggregate value.
MemRef NewLoc(LV.Ptr, Alignment, isVolatile);
- if (DestLoc) {
- Emit(TREE_OPERAND(exp, 1), &NewLoc);
- EmitAggregateCopy(*DestLoc, NewLoc, TREE_TYPE(exp));
- } else if (TREE_CODE(TREE_OPERAND(exp, 0)) != RESULT_DECL) {
- Emit(TREE_OPERAND(exp, 1), &NewLoc);
+ // In case we are returning the contents of an object which overlaps
+ // the place the value is being stored, use a safe function when copying
+ // a value through a pointer into a structure value return block.
+ if (TREE_CODE (lhs) == RESULT_DECL && TREE_CODE (rhs) == INDIRECT_REF) {
+ MemRef Tmp = CreateTempLoc(ConvertType(TREE_TYPE(rhs)));
+ Emit(rhs, &Tmp);
+ EmitAggregateCopy(NewLoc, Tmp, TREE_TYPE(rhs));
} else {
- // We do this for stores into RESULT_DECL because it is possible for that
- // memory area to overlap with the object being stored into it; see
- // gcc.c-torture/execute/20010124-1.c.
-
- MemRef Tmp = CreateTempLoc(ConvertType(TREE_TYPE(TREE_OPERAND(exp,1))));
- Emit(TREE_OPERAND(exp, 1), &Tmp);
- EmitAggregateCopy(NewLoc, Tmp, TREE_TYPE(TREE_OPERAND(exp,1)));
+ Emit(rhs, &NewLoc);
}
+
+ if (DestLoc)
+ EmitAggregateCopy(*DestLoc, NewLoc, TREE_TYPE(exp));
+
return 0;
}
- // Last case, this is a store to a bitfield, so we have to emit a
+ // Last case, this is a store to a bitfield, so we have to emit a
// read/modify/write sequence.
- Value *RHS = Emit(TREE_OPERAND(exp, 1), 0);
+ Value *RHS = Emit(rhs, 0);
if (!LV.BitSize)
return RHS;
@@ -2716,7 +2736,7 @@
assert(ValSizeInBits >= LV.BitSize && "Bad bitfield lvalue!");
assert(2*ValSizeInBits > LV.BitSize+LV.BitStart && "Bad bitfield lvalue!");
- Value *BitSource = CastToAnyType(RHS, Op1Signed, ValTy, Op0Signed);
+ Value *BitSource = CastToAnyType(RHS, RHSSigned, ValTy, LHSSigned);
for (unsigned I = 0; I < Strides; I++) {
unsigned Index = BYTES_BIG_ENDIAN ? Strides - I - 1 : I; // LSB first
Modified: llvm-gcc-4.2/trunk/gcc/llvm-internal.h
URL:
http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/llvm-internal.h?rev=46710&r1=46709&r2=46710&view=diff
==============================================================================
--- llvm-gcc-4.2/trunk/gcc/llvm-internal.h (original)
+++ llvm-gcc-4.2/trunk/gcc/llvm-internal.h Mon Feb 4 11:21:32 2008
@@ -386,6 +386,13 @@
/// instruction's type is a pointer to the specified type.
AllocaInst *CreateTemporary(const Type *Ty);
+ /// CreateTempLoc - Like CreateTemporary, but returns a MemRef.
+ MemRef CreateTempLoc(const Type *Ty);
+
+ /// EmitAggregateCopy - Copy the elements from SrcLoc to DestLoc, using the
+ /// GCC type specified by GCCType to know which elements to copy.
+ void EmitAggregateCopy(MemRef DestLoc, MemRef SrcLoc, tree_node *GCCType);
+
private: // Helper functions.
/// StartFunctionBody - Start the emission of 'fndecl', outputing all
@@ -406,10 +413,6 @@
/// the previous block falls through into it, add an explicit branch.
void EmitBlock(BasicBlock *BB);
- /// EmitAggregateCopy - Copy the elements from SrcLoc to DestLoc, using the
- /// GCC type specified by GCCType to know which elements to copy.
- void EmitAggregateCopy(MemRef DestLoc, MemRef SrcLoc, tree_node *GCCType);
-
/// EmitAggregateZero - Zero the elements of DestLoc.
///
void EmitAggregateZero(MemRef DestLoc, tree_node *GCCType);
@@ -443,9 +446,6 @@
BasicBlock *getPostPad(unsigned RegionNo);
private:
- /// CreateTempLoc - Like CreateTemporary, but returns a MemRef.
- MemRef CreateTempLoc(const Type *Ty);
-
void EmitAutomaticVariableDecl(tree_node *decl);
/// isNoopCast - Return true if a cast from V to Ty does not change any bits.
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