Small structs for PPC64 SVR4 must be passed right-justified in registers.
lib/Target/PowerPC/PPCISelLowering.{h,cpp}
Rename LowerFormalArguments_Darwin to LowerFormalArguments_Darwin_Or_64SVR4.
Rename LowerFormalArguments_SVR4 to LowerFormalArguments_32SVR4.
Receive small structs right-justified in LowerFormalArguments_Darwin_Or_64SVR4.
Rename LowerCall_Darwin to LowerCall_Darwin_Or_64SVR4.
Rename LowerCall_SVR4 to LowerCall_32SVR4.
Pass small structs right-justified in LowerCall_Darwin_Or_64SVR4.
test/CodeGen/PowerPC/structsinregs.ll
New test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164228 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 3b22ac4..2e8fa18 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1717,16 +1717,16 @@
SmallVectorImpl<SDValue> &InVals)
const {
if (PPCSubTarget.isSVR4ABI() && !PPCSubTarget.isPPC64()) {
- return LowerFormalArguments_SVR4(Chain, CallConv, isVarArg, Ins,
- dl, DAG, InVals);
- } else {
- return LowerFormalArguments_Darwin(Chain, CallConv, isVarArg, Ins,
+ return LowerFormalArguments_32SVR4(Chain, CallConv, isVarArg, Ins,
dl, DAG, InVals);
+ } else {
+ return LowerFormalArguments_Darwin_Or_64SVR4(Chain, CallConv, isVarArg, Ins,
+ dl, DAG, InVals);
}
}
SDValue
-PPCTargetLowering::LowerFormalArguments_SVR4(
+PPCTargetLowering::LowerFormalArguments_32SVR4(
SDValue Chain,
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg>
@@ -1944,7 +1944,7 @@
}
SDValue
-PPCTargetLowering::LowerFormalArguments_Darwin(
+PPCTargetLowering::LowerFormalArguments_Darwin_Or_64SVR4(
SDValue Chain,
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg>
@@ -1959,6 +1959,7 @@
EVT PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
bool isPPC64 = PtrVT == MVT::i64;
+ bool isSVR4ABI = PPCSubTarget.isSVR4ABI();
// Potential tail calls could cause overwriting of argument stack slots.
bool isImmutable = !(getTargetMachine().Options.GuaranteedTailCallOpt &&
(CallConv == CallingConv::Fast));
@@ -2019,10 +2020,12 @@
default: llvm_unreachable("Unhandled argument type!");
case MVT::i32:
case MVT::f32:
- VecArgOffset += isPPC64 ? 8 : 4;
+ VecArgOffset += 4;
break;
case MVT::i64: // PPC64
case MVT::f64:
+ // FIXME: We are guaranteed to be !isPPC64 at this point.
+ // Does MVT::i64 apply?
VecArgOffset += 8;
break;
case MVT::v4f32:
@@ -2076,8 +2079,11 @@
// ObjSize is the true size, ArgSize rounded up to multiple of registers.
ObjSize = Flags.getByValSize();
ArgSize = ((ObjSize + PtrByteSize - 1)/PtrByteSize) * PtrByteSize;
- // Objects of size 1 and 2 are right justified, everything else is
- // left justified. This means the memory address is adjusted forwards.
+ // FOR DARWIN: Objects of size 1 and 2 are right justified, everything
+ // else is left justified. This means the memory address is adjusted
+ // forwards.
+ // FOR 64-BIT SVR4: All aggregates smaller than 8 bytes must be passed
+ // right-justified.
if (ObjSize==1 || ObjSize==2) {
CurArgOffset = CurArgOffset + (4 - ObjSize);
}
@@ -2085,7 +2091,8 @@
int FI = MFI->CreateFixedObject(ObjSize, CurArgOffset, true);
SDValue FIN = DAG.getFrameIndex(FI, PtrVT);
InVals.push_back(FIN);
- if (ObjSize==1 || ObjSize==2) {
+ if (ObjSize==1 || ObjSize==2 ||
+ (ObjSize==4 && isSVR4ABI)) {
if (GPR_idx != Num_GPR_Regs) {
unsigned VReg;
if (isPPC64)
@@ -2093,10 +2100,11 @@
else
VReg = MF.addLiveIn(GPR[GPR_idx], &PPC::GPRCRegClass);
SDValue Val = DAG.getCopyFromReg(Chain, dl, VReg, PtrVT);
+ EVT ObjType = (ObjSize == 1 ? MVT::i8 :
+ (ObjSize == 2 ? MVT::i16 : MVT::i32));
SDValue Store = DAG.getTruncStore(Val.getValue(1), dl, Val, FIN,
MachinePointerInfo(),
- ObjSize==1 ? MVT::i8 : MVT::i16,
- false, false, 0);
+ ObjType, false, false, 0);
MemOps.push_back(Store);
++GPR_idx;
}
@@ -2107,8 +2115,8 @@
}
for (unsigned j = 0; j < ArgSize; j += PtrByteSize) {
// Store whatever pieces of the object are in registers
- // to memory. ArgVal will be address of the beginning of
- // the object.
+ // to memory. ArgOffset will be the address of the beginning
+ // of the object.
if (GPR_idx != Num_GPR_Regs) {
unsigned VReg;
if (isPPC64)
@@ -2118,7 +2126,16 @@
int FI = MFI->CreateFixedObject(PtrByteSize, ArgOffset, true);
SDValue FIN = DAG.getFrameIndex(FI, PtrVT);
SDValue Val = DAG.getCopyFromReg(Chain, dl, VReg, PtrVT);
- SDValue Store = DAG.getStore(Val.getValue(1), dl, Val, FIN,
+ SDValue Shifted = Val;
+
+ // For 64-bit SVR4, small structs come in right-adjusted.
+ // Shift them left so the following logic works as expected.
+ if (ObjSize < 8 && isSVR4ABI) {
+ SDValue ShiftAmt = DAG.getConstant(64 - 8 * ObjSize, PtrVT);
+ Shifted = DAG.getNode(ISD::SHL, dl, PtrVT, Val, ShiftAmt);
+ }
+
+ SDValue Store = DAG.getStore(Val.getValue(1), dl, Shifted, FIN,
MachinePointerInfo(),
false, false, 0);
MemOps.push_back(Store);
@@ -2308,8 +2325,8 @@
return Chain;
}
-/// CalculateParameterAndLinkageAreaSize - Get the size of the paramter plus
-/// linkage area for the Darwin ABI.
+/// CalculateParameterAndLinkageAreaSize - Get the size of the parameter plus
+/// linkage area for the Darwin ABI, or the 64-bit SVR4 ABI.
static unsigned
CalculateParameterAndLinkageAreaSize(SelectionDAG &DAG,
bool isPPC64,
@@ -2718,7 +2735,7 @@
// Thus for a call through a function pointer, the following actions need
// to be performed:
// 1. Save the TOC of the caller in the TOC save area of its stack
- // frame (this is done in LowerCall_Darwin()).
+ // frame (this is done in LowerCall_Darwin_Or_64SVR4()).
// 2. Load the address of the function entry point from the function
// descriptor.
// 3. Load the TOC of the callee from the function descriptor into r2.
@@ -2969,25 +2986,25 @@
Ins, DAG);
if (PPCSubTarget.isSVR4ABI() && !PPCSubTarget.isPPC64())
- return LowerCall_SVR4(Chain, Callee, CallConv, isVarArg,
- isTailCall, Outs, OutVals, Ins,
- dl, DAG, InVals);
+ return LowerCall_32SVR4(Chain, Callee, CallConv, isVarArg,
+ isTailCall, Outs, OutVals, Ins,
+ dl, DAG, InVals);
- return LowerCall_Darwin(Chain, Callee, CallConv, isVarArg,
- isTailCall, Outs, OutVals, Ins,
- dl, DAG, InVals);
+ return LowerCall_Darwin_Or_64SVR4(Chain, Callee, CallConv, isVarArg,
+ isTailCall, Outs, OutVals, Ins,
+ dl, DAG, InVals);
}
SDValue
-PPCTargetLowering::LowerCall_SVR4(SDValue Chain, SDValue Callee,
- CallingConv::ID CallConv, bool isVarArg,
- bool isTailCall,
- const SmallVectorImpl<ISD::OutputArg> &Outs,
- const SmallVectorImpl<SDValue> &OutVals,
- const SmallVectorImpl<ISD::InputArg> &Ins,
- DebugLoc dl, SelectionDAG &DAG,
- SmallVectorImpl<SDValue> &InVals) const {
- // See PPCTargetLowering::LowerFormalArguments_SVR4() for a description
+PPCTargetLowering::LowerCall_32SVR4(SDValue Chain, SDValue Callee,
+ CallingConv::ID CallConv, bool isVarArg,
+ bool isTailCall,
+ const SmallVectorImpl<ISD::OutputArg> &Outs,
+ const SmallVectorImpl<SDValue> &OutVals,
+ const SmallVectorImpl<ISD::InputArg> &Ins,
+ DebugLoc dl, SelectionDAG &DAG,
+ SmallVectorImpl<SDValue> &InVals) const {
+ // See PPCTargetLowering::LowerFormalArguments_32SVR4() for a description
// of the 32-bit SVR4 ABI stack frame layout.
assert((CallConv == CallingConv::C ||
@@ -3192,7 +3209,7 @@
}
SDValue
-PPCTargetLowering::LowerCall_Darwin(SDValue Chain, SDValue Callee,
+PPCTargetLowering::LowerCall_Darwin_Or_64SVR4(SDValue Chain, SDValue Callee,
CallingConv::ID CallConv, bool isVarArg,
bool isTailCall,
const SmallVectorImpl<ISD::OutputArg> &Outs,
@@ -3201,6 +3218,8 @@
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
+ bool isSVR4ABI = PPCSubTarget.isSVR4ABI();
+
unsigned NumOps = Outs.size();
EVT PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
@@ -3308,12 +3327,22 @@
}
// FIXME memcpy is used way more than necessary. Correctness first.
+ // Note: "by value" is code for passing a structure by value, not
+ // basic types.
if (Flags.isByVal()) {
+ // Note: Size includes alignment padding, so
+ // struct x { short a; char b; }
+ // will have Size = 4. With #pragma pack(1), it will have Size = 3.
+ // These are the proper values we need for right-justifying the
+ // aggregate in a parameter register for 64-bit SVR4.
unsigned Size = Flags.getByValSize();
- if (Size==1 || Size==2) {
- // Very small objects are passed right-justified.
- // Everything else is passed left-justified.
- EVT VT = (Size==1) ? MVT::i8 : MVT::i16;
+ // FOR DARWIN ONLY: Very small objects are passed right-justified.
+ // Everything else is passed left-justified.
+ // FOR 64-BIT SVR4: All aggregates smaller than 8 bytes must
+ // be passed right-justified.
+ if (Size==1 || Size==2 ||
+ (Size==4 && isSVR4ABI)) {
+ EVT VT = (Size==1) ? MVT::i8 : ((Size==2) ? MVT::i16 : MVT::i32);
if (GPR_idx != NumGPRs) {
SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, PtrVT, Chain, Arg,
MachinePointerInfo(), VT,
@@ -3341,15 +3370,67 @@
// Copy entire object into memory. There are cases where gcc-generated
// code assumes it is there, even if it could be put entirely into
// registers. (This is not what the doc says.)
- SDValue MemcpyCall = CreateCopyOfByValArgument(Arg, PtrOff,
- CallSeqStart.getNode()->getOperand(0),
- Flags, DAG, dl);
- // This must go outside the CALLSEQ_START..END.
- SDValue NewCallSeqStart = DAG.getCALLSEQ_START(MemcpyCall,
- CallSeqStart.getNode()->getOperand(1));
- DAG.ReplaceAllUsesWith(CallSeqStart.getNode(), NewCallSeqStart.getNode());
- Chain = CallSeqStart = NewCallSeqStart;
- // And copy the pieces of it that fit into registers.
+
+ // FIXME: The above statement is likely due to a misunderstanding of the
+ // documents. At least for 64-bit SVR4, all arguments must be copied
+ // into the parameter area BY THE CALLEE in the event that the callee
+ // takes the address of any formal argument. That has not yet been
+ // implemented. However, it is reasonable to use the stack area as a
+ // staging area for the register load.
+
+ // Skip this for small aggregates under 64-bit SVR4, as we will use
+ // the same slot for a right-justified copy, below.
+ if (Size >= 8 || !isSVR4ABI) {
+ SDValue MemcpyCall = CreateCopyOfByValArgument(Arg, PtrOff,
+ CallSeqStart.getNode()->getOperand(0),
+ Flags, DAG, dl);
+ // This must go outside the CALLSEQ_START..END.
+ SDValue NewCallSeqStart = DAG.getCALLSEQ_START(MemcpyCall,
+ CallSeqStart.getNode()->getOperand(1));
+ DAG.ReplaceAllUsesWith(CallSeqStart.getNode(),
+ NewCallSeqStart.getNode());
+ Chain = CallSeqStart = NewCallSeqStart;
+ }
+
+ // FOR 64-BIT SVR4: When a register is available, pass the
+ // aggregate right-justified.
+ if (isSVR4ABI && Size < 8 && GPR_idx != NumGPRs) {
+ // The easiest way to get this right-justified in a register
+ // is to copy the structure into the rightmost portion of a
+ // local variable slot, then load the whole slot into the
+ // register.
+ // FIXME: The memcpy seems to produce pretty awful code for
+ // small aggregates, particularly for packed ones.
+ // FIXME: It would be preferable to use the slot in the
+ // parameter save area instead of a new local variable.
+ SDValue Const = DAG.getConstant(8 - Size, PtrOff.getValueType());
+ SDValue AddPtr = DAG.getNode(ISD::ADD, dl, PtrVT, PtrOff, Const);
+ SDValue MemcpyCall = CreateCopyOfByValArgument(Arg, AddPtr,
+ CallSeqStart.getNode()->getOperand(0),
+ Flags, DAG, dl);
+
+ // Place the memcpy outside the CALLSEQ_START..END.
+ SDValue NewCallSeqStart = DAG.getCALLSEQ_START(MemcpyCall,
+ CallSeqStart.getNode()->getOperand(1));
+ DAG.ReplaceAllUsesWith(CallSeqStart.getNode(),
+ NewCallSeqStart.getNode());
+ Chain = CallSeqStart = NewCallSeqStart;
+
+ // Load the slot into the register.
+ SDValue Load = DAG.getLoad(PtrVT, dl, Chain, PtrOff,
+ MachinePointerInfo(),
+ false, false, false, 0);
+ MemOpChains.push_back(Load.getValue(1));
+ RegsToPass.push_back(std::make_pair(GPR[GPR_idx++], Load));
+
+ // Done with this argument.
+ ArgOffset += PtrByteSize;
+ continue;
+ }
+
+ // For small aggregates (Darwin only) and aggregates >= PtrByteSize,
+ // copy the pieces of the object that fit into registers from the
+ // parameter save area.
for (unsigned j=0; j<Size; j+=PtrByteSize) {
SDValue Const = DAG.getConstant(j, PtrOff.getValueType());
SDValue AddArg = DAG.getNode(ISD::ADD, dl, PtrVT, Arg, Const);