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[mips][PR19612] Fix va_arg for big-endian mode.

Summary:
Big-endian mode was not correctly adjusting the offset for types smaller
than an ABI slot.

Fixes PR19612

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: sstankovic, llvm-commits

Differential Revision: http://reviews.llvm.org/D4556

llvm-svn: 223007
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@dsandersllvm
dsandersllvm committed Dec 1, 2014
1 parent 2c03fbf commit 4feb6fe
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Showing 4 changed files with 1,185 additions and 11 deletions.
69 changes: 67 additions & 2 deletions llvm/lib/Target/Mips/MipsISelLowering.cpp
View file
Expand Up @@ -251,7 +251,6 @@ MipsTargetLowering::MipsTargetLowering(MipsTargetMachine &TM,
setOperationAction(ISD::SETCC, MVT::f32, Custom);
setOperationAction(ISD::SETCC, MVT::f64, Custom);
setOperationAction(ISD::BRCOND, MVT::Other, Custom);
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::FCOPYSIGN, MVT::f32, Custom);
setOperationAction(ISD::FCOPYSIGN, MVT::f64, Custom);
setOperationAction(ISD::FP_TO_SINT, MVT::i32, Custom);
Expand Down Expand Up @@ -343,7 +342,8 @@ MipsTargetLowering::MipsTargetLowering(MipsTargetMachine &TM,

setOperationAction(ISD::EH_RETURN, MVT::Other, Custom);

setOperationAction(ISD::VAARG, MVT::Other, Expand);
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::VAARG, MVT::Other, Custom);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
setOperationAction(ISD::VAEND, MVT::Other, Expand);

Expand Down Expand Up @@ -392,6 +392,11 @@ MipsTargetLowering::MipsTargetLowering(MipsTargetMachine &TM,

setMinFunctionAlignment(Subtarget.isGP64bit() ? 3 : 2);

// The arguments on the stack are defined in terms of 4-byte slots on O32
// and 8-byte slots on N32/N64.
setMinStackArgumentAlignment(
(Subtarget.isABI_N32() || Subtarget.isABI_N64()) ? 8 : 4);

setStackPointerRegisterToSaveRestore(Subtarget.isABI_N64() ? Mips::SP_64
: Mips::SP);

Expand Down Expand Up @@ -792,6 +797,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const
case ISD::SELECT_CC: return lowerSELECT_CC(Op, DAG);
case ISD::SETCC: return lowerSETCC(Op, DAG);
case ISD::VASTART: return lowerVASTART(Op, DAG);
case ISD::VAARG: return lowerVAARG(Op, DAG);
case ISD::FCOPYSIGN: return lowerFCOPYSIGN(Op, DAG);
case ISD::FRAMEADDR: return lowerFRAMEADDR(Op, DAG);
case ISD::RETURNADDR: return lowerRETURNADDR(Op, DAG);
Expand Down Expand Up @@ -1755,6 +1761,65 @@ SDValue MipsTargetLowering::lowerVASTART(SDValue Op, SelectionDAG &DAG) const {
MachinePointerInfo(SV), false, false, 0);
}

SDValue MipsTargetLowering::lowerVAARG(SDValue Op, SelectionDAG &DAG) const {
SDNode *Node = Op.getNode();
EVT VT = Node->getValueType(0);
SDValue Chain = Node->getOperand(0);
SDValue VAListPtr = Node->getOperand(1);
unsigned Align = Node->getConstantOperandVal(3);
const Value *SV = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
SDLoc DL(Node);
unsigned ArgSlotSizeInBytes =
(Subtarget.isABI_N32() || Subtarget.isABI_N64()) ? 8 : 4;

SDValue VAListLoad = DAG.getLoad(getPointerTy(), DL, Chain, VAListPtr,
MachinePointerInfo(SV), false, false, false,
0);
SDValue VAList = VAListLoad;

// Re-align the pointer if necessary.
// It should only ever be necessary for 64-bit types on O32 since the minimum
// argument alignment is the same as the maximum type alignment for N32/N64.
//
// FIXME: We currently align too often. The code generator doesn't notice
// when the pointer is still aligned from the last va_arg (or pair of
// va_args for the i64 on O32 case).
if (Align > getMinStackArgumentAlignment()) {
assert(((Align & (Align-1)) == 0) && "Expected Align to be a power of 2");

VAList = DAG.getNode(ISD::ADD, DL, VAList.getValueType(), VAList,
DAG.getConstant(Align - 1,
VAList.getValueType()));

VAList = DAG.getNode(ISD::AND, DL, VAList.getValueType(), VAList,
DAG.getConstant(-(int64_t)Align,
VAList.getValueType()));
}

// Increment the pointer, VAList, to the next vaarg.
unsigned ArgSizeInBytes = getDataLayout()->getTypeAllocSize(VT.getTypeForEVT(*DAG.getContext()));
SDValue Tmp3 = DAG.getNode(ISD::ADD, DL, VAList.getValueType(), VAList,
DAG.getConstant(RoundUpToAlignment(ArgSizeInBytes, ArgSlotSizeInBytes),
VAList.getValueType()));
// Store the incremented VAList to the legalized pointer
Chain = DAG.getStore(VAListLoad.getValue(1), DL, Tmp3, VAListPtr,
MachinePointerInfo(SV), false, false, 0);

// In big-endian mode we must adjust the pointer when the load size is smaller
// than the argument slot size. We must also reduce the known alignment to
// match. For example in the N64 ABI, we must add 4 bytes to the offset to get
// the correct half of the slot, and reduce the alignment from 8 (slot
// alignment) down to 4 (type alignment).
if (!Subtarget.isLittle() && ArgSizeInBytes < ArgSlotSizeInBytes) {
unsigned Adjustment = ArgSlotSizeInBytes - ArgSizeInBytes;
VAList = DAG.getNode(ISD::ADD, DL, VAListPtr.getValueType(), VAList,
DAG.getIntPtrConstant(Adjustment));
}
// Load the actual argument out of the pointer VAList
return DAG.getLoad(VT, DL, Chain, VAList, MachinePointerInfo(), false, false,
false, 0);
}

static SDValue lowerFCOPYSIGN32(SDValue Op, SelectionDAG &DAG,
bool HasExtractInsert) {
EVT TyX = Op.getOperand(0).getValueType();
Expand Down
1 change: 1 addition & 0 deletions llvm/lib/Target/Mips/MipsISelLowering.h
View file
Expand Up @@ -482,6 +482,7 @@ namespace llvm {
SDValue lowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSETCC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerVASTART(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerVAARG(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerFABS(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
Expand Down
22 changes: 13 additions & 9 deletions llvm/test/CodeGen/Mips/cconv/arguments-hard-float-varargs.ll
View file
Expand Up @@ -4,11 +4,11 @@
; RUN-TODO: llc -march=mips64 -relocation-model=static -mattr=-n64,+o32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=O32 %s
; RUN-TODO: llc -march=mips64el -relocation-model=static -mattr=-n64,+o32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=O32 %s

; RUN: llc -march=mips64 -relocation-model=static -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=N32 --check-prefix=NEW %s
; RUN: llc -march=mips64el -relocation-model=static -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=N32 --check-prefix=NEW %s
; RUN: llc -march=mips64 -relocation-model=static -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=N32 --check-prefix=NEW --check-prefix=NEWBE %s
; RUN: llc -march=mips64el -relocation-model=static -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM32 --check-prefix=N32 --check-prefix=NEW --check-prefix=NEWLE %s

; RUN: llc -march=mips64 -relocation-model=static -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM64 --check-prefix=N64 --check-prefix=NEW %s
; RUN: llc -march=mips64el -relocation-model=static -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM64 --check-prefix=N64 --check-prefix=NEW %s
; RUN: llc -march=mips64 -relocation-model=static -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM64 --check-prefix=N64 --check-prefix=NEW --check-prefix=NEWBE %s
; RUN: llc -march=mips64el -relocation-model=static -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=SYM64 --check-prefix=N64 --check-prefix=NEW --check-prefix=NEWLE %s

; Test the effect of varargs on floating point types in the non-variable part
; of the argument list as specified by section 2 of the MIPSpro N32 Handbook.
Expand All @@ -34,6 +34,7 @@ entry:
%b = va_arg i8** %ap, double
%1 = getelementptr [11 x double]* @doubles, i32 0, i32 2
store volatile double %b, double* %1
call void @llvm.va_end(i8* %ap2)
ret void
}

Expand Down Expand Up @@ -98,6 +99,7 @@ entry:
%b = va_arg i8** %ap, float
%1 = getelementptr [11 x float]* @floats, i32 0, i32 2
store volatile float %b, float* %1
call void @llvm.va_end(i8* %ap2)
ret void
}

Expand Down Expand Up @@ -140,16 +142,18 @@ entry:
; Increment the pointer then get the varargs arg
; LLVM will rebind the load to the stack pointer instead of the varargs pointer
; during lowering. This is fine and doesn't change the behaviour.
; N32/N64 is using ori instead of addiu/daddiu but (although odd) this is fine
; since the stack is always aligned.
; Also, in big-endian mode the offset must be increased by 4 to retrieve the
; correct half of the argument slot.
;
; O32-DAG: addiu [[VAPTR]], [[VAPTR]], 4
; O32-DAG: sw [[VAPTR]], 4($sp)
; N32-DAG: ori [[VAPTR]], [[VAPTR]], 4
; N32-DAG: addiu [[VAPTR]], [[VAPTR]], 8
; N32-DAG: sw [[VAPTR]], 4($sp)
; N64-DAG: ori [[VAPTR]], [[VAPTR]], 4
; N64-DAG: daddiu [[VAPTR]], [[VAPTR]], 8
; N64-DAG: sd [[VAPTR]], 0($sp)
; O32-DAG: lwc1 [[FTMP1:\$f[0-9]+]], 12($sp)
; NEW-DAG: lwc1 [[FTMP1:\$f[0-9]+]], 8($sp)
; NEWLE-DAG: lwc1 [[FTMP1:\$f[0-9]+]], 8($sp)
; NEWBE-DAG: lwc1 [[FTMP1:\$f[0-9]+]], 12($sp)
; ALL-DAG: swc1 [[FTMP1]], 8([[R2]])

declare void @llvm.va_start(i8*)
Expand Down

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