Tail call optimization improvements:
Move platform independent code (lowering of possibly overwritten
arguments, check for tail call optimization eligibility) from
target X86ISelectionLowering.cpp to TargetLowering.h and
SelectionDAGISel.cpp.
Initial PowerPC tail call implementation:
Support ppc32 implemented and tested (passes my tests and
test-suite llvm-test).
Support ppc64 implemented and half tested (passes my tests).
On ppc tail call optimization is performed if
caller and callee are fastcc
call is a tail call (in tail call position, call followed by ret)
no variable argument lists or byval arguments
option -tailcallopt is enabled
Supported:
* non pic tail calls on linux/darwin
* module-local tail calls on linux(PIC/GOT)/darwin(PIC)
* inter-module tail calls on darwin(PIC)
If constraints are not met a normal call will be emitted.
A test checking the argument lowering behaviour on x86-64 was added.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50477 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index d3f410e..37b8e7b 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -26,9 +26,11 @@
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Intrinsics.h"
+#include "llvm/ParameterAttributes.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
@@ -412,6 +414,8 @@
case PPCISD::MTFSB1: return "PPCISD::MTFSB1";
case PPCISD::FADDRTZ: return "PPCISD::FADDRTZ";
case PPCISD::MTFSF: return "PPCISD::MTFSF";
+ case PPCISD::TAILCALL: return "PPCISD::TAILCALL";
+ case PPCISD::TC_RETURN: return "PPCISD::TC_RETURN";
}
}
@@ -1317,6 +1321,20 @@
return FPR;
}
+/// CalculateStackSlotSize - Calculates the size reserved for this argument on
+/// the stack.
+static unsigned CalculateStackSlotSize(SDOperand Arg, SDOperand Flag,
+ bool isVarArg, unsigned PtrByteSize) {
+ MVT::ValueType ArgVT = Arg.getValueType();
+ ISD::ArgFlagsTy Flags = cast<ARG_FLAGSSDNode>(Flag)->getArgFlags();
+ unsigned ArgSize =MVT::getSizeInBits(ArgVT)/8;
+ if (Flags.isByVal())
+ ArgSize = Flags.getByValSize();
+ ArgSize = ((ArgSize + PtrByteSize - 1)/PtrByteSize) * PtrByteSize;
+
+ return ArgSize;
+}
+
SDOperand
PPCTargetLowering::LowerFORMAL_ARGUMENTS(SDOperand Op,
SelectionDAG &DAG,
@@ -1338,10 +1356,15 @@
bool isPPC64 = PtrVT == MVT::i64;
bool isMachoABI = Subtarget.isMachoABI();
bool isELF32_ABI = Subtarget.isELF32_ABI();
+ // Potential tail calls could cause overwriting of argument stack slots.
+ unsigned CC = MF.getFunction()->getCallingConv();
+ bool isImmutable = !(PerformTailCallOpt && (CC==CallingConv::Fast));
unsigned PtrByteSize = isPPC64 ? 8 : 4;
unsigned ArgOffset = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
-
+ // Area that is at least reserved in caller of this function.
+ unsigned MinReservedArea = ArgOffset;
+
static const unsigned GPR_32[] = { // 32-bit registers.
PPC::R3, PPC::R4, PPC::R5, PPC::R6,
PPC::R7, PPC::R8, PPC::R9, PPC::R10,
@@ -1426,7 +1449,7 @@
// even GPR_idx value or to an even ArgOffset value.
SmallVector<SDOperand, 8> MemOps;
-
+ unsigned nAltivecParamsAtEnd = 0;
for (unsigned ArgNo = 0, e = Op.Val->getNumValues()-1; ArgNo != e; ++ArgNo) {
SDOperand ArgVal;
bool needsLoad = false;
@@ -1440,6 +1463,23 @@
unsigned CurArgOffset = ArgOffset;
+ // Varargs or 64 bit Altivec parameters are padded to a 16 byte boundary.
+ if (ObjectVT==MVT::v4f32 || ObjectVT==MVT::v4i32 ||
+ ObjectVT==MVT::v8i16 || ObjectVT==MVT::v16i8) {
+ if (isVarArg || isPPC64) {
+ MinReservedArea = ((MinReservedArea+15)/16)*16;
+ MinReservedArea += CalculateStackSlotSize(Op.getValue(ArgNo),
+ Op.getOperand(ArgNo+3),
+ isVarArg,
+ PtrByteSize);
+ } else nAltivecParamsAtEnd++;
+ } else
+ // Calculate min reserved area.
+ MinReservedArea += CalculateStackSlotSize(Op.getValue(ArgNo),
+ Op.getOperand(ArgNo+3),
+ isVarArg,
+ PtrByteSize);
+
// FIXME alignment for ELF may not be right
// FIXME the codegen can be much improved in some cases.
// We do not have to keep everything in memory.
@@ -1614,7 +1654,8 @@
// that we ran out of physical registers of the appropriate type.
if (needsLoad) {
int FI = MFI->CreateFixedObject(ObjSize,
- CurArgOffset + (ArgSize - ObjSize));
+ CurArgOffset + (ArgSize - ObjSize),
+ isImmutable);
SDOperand FIN = DAG.getFrameIndex(FI, PtrVT);
ArgVal = DAG.getLoad(ObjectVT, Root, FIN, NULL, 0);
}
@@ -1622,6 +1663,25 @@
ArgValues.push_back(ArgVal);
}
+ // Set the size that is at least reserved in caller of this function. Tail
+ // call optimized function's reserved stack space needs to be aligned so that
+ // taking the difference between two stack areas will result in an aligned
+ // stack.
+ PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+ // Add the Altivec parameters at the end, if needed.
+ if (nAltivecParamsAtEnd) {
+ MinReservedArea = ((MinReservedArea+15)/16)*16;
+ MinReservedArea += 16*nAltivecParamsAtEnd;
+ }
+ MinReservedArea =
+ std::max(MinReservedArea,
+ PPCFrameInfo::getMinCallFrameSize(isPPC64, isMachoABI));
+ unsigned TargetAlign = DAG.getMachineFunction().getTarget().getFrameInfo()->
+ getStackAlignment();
+ unsigned AlignMask = TargetAlign-1;
+ MinReservedArea = (MinReservedArea + AlignMask) & ~AlignMask;
+ FI->setMinReservedArea(MinReservedArea);
+
// If the function takes variable number of arguments, make a frame index for
// the start of the first vararg value... for expansion of llvm.va_start.
if (isVarArg) {
@@ -1720,6 +1780,131 @@
return DAG.getNode(ISD::MERGE_VALUES, RetVT, &ArgValues[0], ArgValues.size());
}
+/// CalculateParameterAndLinkageAreaSize - Get the size of the paramter plus
+/// linkage area.
+static unsigned
+CalculateParameterAndLinkageAreaSize(SelectionDAG &DAG,
+ bool isPPC64,
+ bool isMachoABI,
+ bool isVarArg,
+ unsigned CC,
+ SDOperand Call,
+ unsigned &nAltivecParamsAtEnd) {
+ // Count how many bytes are to be pushed on the stack, including the linkage
+ // area, and parameter passing area. We start with 24/48 bytes, which is
+ // prereserved space for [SP][CR][LR][3 x unused].
+ unsigned NumBytes = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
+ unsigned NumOps = (Call.getNumOperands() - 5) / 2;
+ unsigned PtrByteSize = isPPC64 ? 8 : 4;
+
+ // Add up all the space actually used.
+ // In 32-bit non-varargs calls, Altivec parameters all go at the end; usually
+ // they all go in registers, but we must reserve stack space for them for
+ // possible use by the caller. In varargs or 64-bit calls, parameters are
+ // assigned stack space in order, with padding so Altivec parameters are
+ // 16-byte aligned.
+ nAltivecParamsAtEnd = 0;
+ for (unsigned i = 0; i != NumOps; ++i) {
+ SDOperand Arg = Call.getOperand(5+2*i);
+ SDOperand Flag = Call.getOperand(5+2*i+1);
+ MVT::ValueType ArgVT = Arg.getValueType();
+ // Varargs Altivec parameters are padded to a 16 byte boundary.
+ if (ArgVT==MVT::v4f32 || ArgVT==MVT::v4i32 ||
+ ArgVT==MVT::v8i16 || ArgVT==MVT::v16i8) {
+ if (!isVarArg && !isPPC64) {
+ // Non-varargs Altivec parameters go after all the non-Altivec
+ // parameters; handle those later so we know how much padding we need.
+ nAltivecParamsAtEnd++;
+ continue;
+ }
+ // Varargs and 64-bit Altivec parameters are padded to 16 byte boundary.
+ NumBytes = ((NumBytes+15)/16)*16;
+ }
+ NumBytes += CalculateStackSlotSize(Arg, Flag, isVarArg, PtrByteSize);
+ }
+
+ // Allow for Altivec parameters at the end, if needed.
+ if (nAltivecParamsAtEnd) {
+ NumBytes = ((NumBytes+15)/16)*16;
+ NumBytes += 16*nAltivecParamsAtEnd;
+ }
+
+ // The prolog code of the callee may store up to 8 GPR argument registers to
+ // the stack, allowing va_start to index over them in memory if its varargs.
+ // Because we cannot tell if this is needed on the caller side, we have to
+ // conservatively assume that it is needed. As such, make sure we have at
+ // least enough stack space for the caller to store the 8 GPRs.
+ NumBytes = std::max(NumBytes,
+ PPCFrameInfo::getMinCallFrameSize(isPPC64, isMachoABI));
+
+ // Tail call needs the stack to be aligned.
+ if (CC==CallingConv::Fast && PerformTailCallOpt) {
+ unsigned TargetAlign = DAG.getMachineFunction().getTarget().getFrameInfo()->
+ getStackAlignment();
+ unsigned AlignMask = TargetAlign-1;
+ NumBytes = (NumBytes + AlignMask) & ~AlignMask;
+ }
+
+ return NumBytes;
+}
+
+/// CalculateTailCallSPDiff - Get the amount the stack pointer has to be
+/// adjusted to accomodate the arguments for the tailcall.
+static int CalculateTailCallSPDiff(SelectionDAG& DAG, bool IsTailCall,
+ unsigned ParamSize) {
+
+ if (!IsTailCall) return 0;
+
+ PPCFunctionInfo *FI = DAG.getMachineFunction().getInfo<PPCFunctionInfo>();
+ unsigned CallerMinReservedArea = FI->getMinReservedArea();
+ int SPDiff = (int)CallerMinReservedArea - (int)ParamSize;
+ // Remember only if the new adjustement is bigger.
+ if (SPDiff < FI->getTailCallSPDelta())
+ FI->setTailCallSPDelta(SPDiff);
+
+ return SPDiff;
+}
+
+/// IsEligibleForTailCallElimination - Check to see whether the next instruction
+/// following the call is a return. A function is eligible if caller/callee
+/// calling conventions match, currently only fastcc supports tail calls, and
+/// the function CALL is immediatly followed by a RET.
+bool
+PPCTargetLowering::IsEligibleForTailCallOptimization(SDOperand Call,
+ SDOperand Ret,
+ SelectionDAG& DAG) const {
+ // Variable argument functions are not supported.
+ if (!PerformTailCallOpt ||
+ cast<ConstantSDNode>(Call.getOperand(2))->getValue() != 0) return false;
+
+ if (CheckTailCallReturnConstraints(Call, Ret)) {
+ MachineFunction &MF = DAG.getMachineFunction();
+ unsigned CallerCC = MF.getFunction()->getCallingConv();
+ unsigned CalleeCC = cast<ConstantSDNode>(Call.getOperand(1))->getValue();
+ if (CalleeCC == CallingConv::Fast && CallerCC == CalleeCC) {
+ // Functions containing by val parameters are not supported.
+ for (unsigned i = 0; i != ((Call.getNumOperands()-5)/2); i++) {
+ ISD::ArgFlagsTy Flags = cast<ARG_FLAGSSDNode>(Call.getOperand(5+2*i+1))
+ ->getArgFlags();
+ if (Flags.isByVal()) return false;
+ }
+
+ SDOperand Callee = Call.getOperand(4);
+ // Non PIC/GOT tail calls are supported.
+ if (getTargetMachine().getRelocationModel() != Reloc::PIC_)
+ return true;
+
+ // At the moment we can only do local tail calls (in same module, hidden
+ // or protected) if we are generating PIC.
+ if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+ return G->getGlobal()->hasHiddenVisibility()
+ || G->getGlobal()->hasProtectedVisibility();
+ }
+ }
+
+ return false;
+}
+
/// isCallCompatibleAddress - Return the immediate to use if the specified
/// 32-bit value is representable in the immediate field of a BxA instruction.
static SDNode *isBLACompatibleAddress(SDOperand Op, SelectionDAG &DAG) {
@@ -1735,6 +1920,102 @@
DAG.getTargetLoweringInfo().getPointerTy()).Val;
}
+struct TailCallArgumentInfo {
+ SDOperand Arg;
+ SDOperand FrameIdxOp;
+ int FrameIdx;
+
+ TailCallArgumentInfo() : FrameIdx(0) {}
+};
+
+/// StoreTailCallArgumentsToStackSlot - Stores arguments to their stack slot.
+static void
+StoreTailCallArgumentsToStackSlot(SelectionDAG &DAG,
+ SDOperand Chain,
+ const SmallVector<TailCallArgumentInfo, 8> &TailCallArgs,
+ SmallVector<SDOperand, 8> &MemOpChains) {
+ for (unsigned i = 0, e = TailCallArgs.size(); i != e; ++i) {
+ SDOperand Arg = TailCallArgs[i].Arg;
+ SDOperand FIN = TailCallArgs[i].FrameIdxOp;
+ int FI = TailCallArgs[i].FrameIdx;
+ // Store relative to framepointer.
+ MemOpChains.push_back(DAG.getStore(Chain, Arg, FIN,
+ PseudoSourceValue::getFixedStack(),
+ FI));
+ }
+}
+
+/// EmitTailCallStoreFPAndRetAddr - Move the frame pointer and return address to
+/// the appropriate stack slot for the tail call optimized function call.
+static SDOperand EmitTailCallStoreFPAndRetAddr(SelectionDAG &DAG,
+ MachineFunction &MF,
+ SDOperand Chain,
+ SDOperand OldRetAddr,
+ SDOperand OldFP,
+ int SPDiff,
+ bool isPPC64,
+ bool isMachoABI) {
+ if (SPDiff) {
+ // Calculate the new stack slot for the return address.
+ int SlotSize = isPPC64 ? 8 : 4;
+ int NewRetAddrLoc = SPDiff + PPCFrameInfo::getReturnSaveOffset(isPPC64,
+ isMachoABI);
+ int NewRetAddr = MF.getFrameInfo()->CreateFixedObject(SlotSize,
+ NewRetAddrLoc);
+ int NewFPLoc = SPDiff + PPCFrameInfo::getFramePointerSaveOffset(isPPC64,
+ isMachoABI);
+ int NewFPIdx = MF.getFrameInfo()->CreateFixedObject(SlotSize, NewFPLoc);
+
+ MVT::ValueType VT = isPPC64 ? MVT::i64 : MVT::i32;
+ SDOperand NewRetAddrFrIdx = DAG.getFrameIndex(NewRetAddr, VT);
+ Chain = DAG.getStore(Chain, OldRetAddr, NewRetAddrFrIdx,
+ PseudoSourceValue::getFixedStack(), NewRetAddr);
+ SDOperand NewFramePtrIdx = DAG.getFrameIndex(NewFPIdx, VT);
+ Chain = DAG.getStore(Chain, OldFP, NewFramePtrIdx,
+ PseudoSourceValue::getFixedStack(), NewFPIdx);
+ }
+ return Chain;
+}
+
+/// CalculateTailCallArgDest - Remember Argument for later processing. Calculate
+/// the position of the argument.
+static void
+CalculateTailCallArgDest(SelectionDAG &DAG, MachineFunction &MF, bool isPPC64,
+ SDOperand Arg, int SPDiff, unsigned ArgOffset,
+ SmallVector<TailCallArgumentInfo, 8>& TailCallArguments) {
+ int Offset = ArgOffset + SPDiff;
+ uint32_t OpSize = (MVT::getSizeInBits(Arg.getValueType())+7)/8;
+ int FI = MF.getFrameInfo()->CreateFixedObject(OpSize, Offset);
+ MVT::ValueType VT = isPPC64 ? MVT::i64 : MVT::i32;
+ SDOperand FIN = DAG.getFrameIndex(FI, VT);
+ TailCallArgumentInfo Info;
+ Info.Arg = Arg;
+ Info.FrameIdxOp = FIN;
+ Info.FrameIdx = FI;
+ TailCallArguments.push_back(Info);
+}
+
+/// EmitTCFPAndRetAddrLoad - Emit load from frame pointer and return address
+/// stack slot. Returns the chain as result and the loaded frame pointers in
+/// LROpOut/FPOpout. Used when tail calling.
+SDOperand PPCTargetLowering::EmitTailCallLoadFPAndRetAddr(SelectionDAG & DAG,
+ int SPDiff,
+ SDOperand Chain,
+ SDOperand &LROpOut,
+ SDOperand &FPOpOut) {
+ if (SPDiff) {
+ // Load the LR and FP stack slot for later adjusting.
+ MVT::ValueType VT = PPCSubTarget.isPPC64() ? MVT::i64 : MVT::i32;
+ LROpOut = getReturnAddrFrameIndex(DAG);
+ LROpOut = DAG.getLoad(VT, Chain, LROpOut, NULL, 0);
+ Chain = SDOperand(LROpOut.Val, 1);
+ FPOpOut = getFramePointerFrameIndex(DAG);
+ FPOpOut = DAG.getLoad(VT, Chain, FPOpOut, NULL, 0);
+ Chain = SDOperand(FPOpOut.Val, 1);
+ }
+ return Chain;
+}
+
/// CreateCopyOfByValArgument - Make a copy of an aggregate at address specified
/// by "Src" to address "Dst" of size "Size". Alignment information is
/// specified by the specific parameter attribute. The copy will be passed as
@@ -1750,11 +2031,39 @@
NULL, 0, NULL, 0);
}
+/// LowerMemOpCallTo - Store the argument to the stack or remember it in case of
+/// tail calls.
+static void
+LowerMemOpCallTo(SelectionDAG &DAG, MachineFunction &MF, SDOperand Chain,
+ SDOperand Arg, SDOperand PtrOff, int SPDiff,
+ unsigned ArgOffset, bool isPPC64, bool isTailCall,
+ bool isVector, SmallVector<SDOperand, 8> &MemOpChains,
+ SmallVector<TailCallArgumentInfo, 8>& TailCallArguments) {
+ MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+ if (!isTailCall) {
+ if (isVector) {
+ SDOperand StackPtr;
+ if (isPPC64)
+ StackPtr = DAG.getRegister(PPC::X1, MVT::i64);
+ else
+ StackPtr = DAG.getRegister(PPC::R1, MVT::i32);
+ PtrOff = DAG.getNode(ISD::ADD, PtrVT, StackPtr,
+ DAG.getConstant(ArgOffset, PtrVT));
+ }
+ MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
+ // Calculate and remember argument location.
+ } else CalculateTailCallArgDest(DAG, MF, isPPC64, Arg, SPDiff, ArgOffset,
+ TailCallArguments);
+}
+
SDOperand PPCTargetLowering::LowerCALL(SDOperand Op, SelectionDAG &DAG,
const PPCSubtarget &Subtarget,
TargetMachine &TM) {
SDOperand Chain = Op.getOperand(0);
bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getValue() != 0;
+ unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getValue();
+ bool isTailCall = cast<ConstantSDNode>(Op.getOperand(3))->getValue() != 0 &&
+ CC == CallingConv::Fast && PerformTailCallOpt;
SDOperand Callee = Op.getOperand(4);
unsigned NumOps = (Op.getNumOperands() - 5) / 2;
@@ -1765,58 +2074,32 @@
bool isPPC64 = PtrVT == MVT::i64;
unsigned PtrByteSize = isPPC64 ? 8 : 4;
+ MachineFunction &MF = DAG.getMachineFunction();
+
// args_to_use will accumulate outgoing args for the PPCISD::CALL case in
// SelectExpr to use to put the arguments in the appropriate registers.
std::vector<SDOperand> args_to_use;
+ // Mark this function as potentially containing a function that contains a
+ // tail call. As a consequence the frame pointer will be used for dynamicalloc
+ // and restoring the callers stack pointer in this functions epilog. This is
+ // done because by tail calling the called function might overwrite the value
+ // in this function's (MF) stack pointer stack slot 0(SP).
+ if (PerformTailCallOpt && CC==CallingConv::Fast)
+ MF.getInfo<PPCFunctionInfo>()->setHasFastCall();
+
+ unsigned nAltivecParamsAtEnd = 0;
+
// Count how many bytes are to be pushed on the stack, including the linkage
// area, and parameter passing area. We start with 24/48 bytes, which is
// prereserved space for [SP][CR][LR][3 x unused].
- unsigned NumBytes = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
+ unsigned NumBytes =
+ CalculateParameterAndLinkageAreaSize(DAG, isPPC64, isMachoABI, isVarArg, CC,
+ Op, nAltivecParamsAtEnd);
- // Add up all the space actually used.
- // In 32-bit non-varargs calls, Altivec parameters all go at the end; usually
- // they all go in registers, but we must reserve stack space for them for
- // possible use by the caller. In varargs or 64-bit calls, parameters are
- // assigned stack space in order, with padding so Altivec parameters are
- // 16-byte aligned.
- unsigned nAltivecParamsAtEnd = 0;
- for (unsigned i = 0; i != NumOps; ++i) {
- SDOperand Arg = Op.getOperand(5+2*i);
- MVT::ValueType ArgVT = Arg.getValueType();
- if (ArgVT==MVT::v4f32 || ArgVT==MVT::v4i32 ||
- ArgVT==MVT::v8i16 || ArgVT==MVT::v16i8) {
- if (!isVarArg && !isPPC64) {
- // Non-varargs Altivec parameters go after all the non-Altivec parameters;
- // do those last so we know how much padding we need.
- nAltivecParamsAtEnd++;
- continue;
- } else {
- // Varargs and 64-bit Altivec parameters are padded to 16 byte boundary.
- NumBytes = ((NumBytes+15)/16)*16;
- }
- }
- ISD::ArgFlagsTy Flags =
- cast<ARG_FLAGSSDNode>(Op.getOperand(5+2*i+1))->getArgFlags();
- unsigned ArgSize =MVT::getSizeInBits(Op.getOperand(5+2*i).getValueType())/8;
- if (Flags.isByVal())
- ArgSize = Flags.getByValSize();
- ArgSize = ((ArgSize + PtrByteSize - 1)/PtrByteSize) * PtrByteSize;
- NumBytes += ArgSize;
- }
- // Allow for Altivec parameters at the end, if needed.
- if (nAltivecParamsAtEnd) {
- NumBytes = ((NumBytes+15)/16)*16;
- NumBytes += 16*nAltivecParamsAtEnd;
- }
-
- // The prolog code of the callee may store up to 8 GPR argument registers to
- // the stack, allowing va_start to index over them in memory if its varargs.
- // Because we cannot tell if this is needed on the caller side, we have to
- // conservatively assume that it is needed. As such, make sure we have at
- // least enough stack space for the caller to store the 8 GPRs.
- NumBytes = std::max(NumBytes,
- PPCFrameInfo::getMinCallFrameSize(isPPC64, isMachoABI));
+ // Calculate by how many bytes the stack has to be adjusted in case of tail
+ // call optimization.
+ int SPDiff = CalculateTailCallSPDiff(DAG, isTailCall, NumBytes);
// Adjust the stack pointer for the new arguments...
// These operations are automatically eliminated by the prolog/epilog pass
@@ -1824,6 +2107,11 @@
DAG.getConstant(NumBytes, PtrVT));
SDOperand CallSeqStart = Chain;
+ // Load the return address and frame pointer so it can be move somewhere else
+ // later.
+ SDOperand LROp, FPOp;
+ Chain = EmitTailCallLoadFPAndRetAddr(DAG, SPDiff, Chain, LROp, FPOp);
+
// Set up a copy of the stack pointer for use loading and storing any
// arguments that may not fit in the registers available for argument
// passing.
@@ -1861,6 +2149,8 @@
const unsigned *GPR = isPPC64 ? GPR_64 : GPR_32;
std::vector<std::pair<unsigned, SDOperand> > RegsToPass;
+ SmallVector<TailCallArgumentInfo, 8> TailCallArguments;
+
SmallVector<SDOperand, 8> MemOpChains;
for (unsigned i = 0; i != NumOps; ++i) {
bool inMem = false;
@@ -1959,7 +2249,9 @@
if (GPR_idx != NumGPRs) {
RegsToPass.push_back(std::make_pair(GPR[GPR_idx++], Arg));
} else {
- MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
+ LowerMemOpCallTo(DAG, MF, Chain, Arg, PtrOff, SPDiff, ArgOffset,
+ isPPC64, isTailCall, false, MemOpChains,
+ TailCallArguments);
inMem = true;
}
if (inMem || isMachoABI) {
@@ -2007,7 +2299,9 @@
}
}
} else {
- MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
+ LowerMemOpCallTo(DAG, MF, Chain, Arg, PtrOff, SPDiff, ArgOffset,
+ isPPC64, isTailCall, false, MemOpChains,
+ TailCallArguments);
inMem = true;
}
if (inMem || isMachoABI) {
@@ -2058,6 +2352,7 @@
}
break;
}
+
// Non-varargs Altivec params generally go in registers, but have
// stack space allocated at the end.
if (VR_idx != NumVRs) {
@@ -2065,10 +2360,9 @@
RegsToPass.push_back(std::make_pair(VR[VR_idx++], Arg));
} else if (nAltivecParamsAtEnd==0) {
// We are emitting Altivec params in order.
- PtrOff = DAG.getNode(ISD::ADD, PtrVT, StackPtr,
- DAG.getConstant(ArgOffset, PtrVT));
- SDOperand Store = DAG.getStore(Chain, Arg, PtrOff, NULL, 0);
- MemOpChains.push_back(Store);
+ LowerMemOpCallTo(DAG, MF, Chain, Arg, PtrOff, SPDiff, ArgOffset,
+ isPPC64, isTailCall, true, MemOpChains,
+ TailCallArguments);
ArgOffset += 16;
}
break;
@@ -2090,10 +2384,11 @@
if (ArgType==MVT::v4f32 || ArgType==MVT::v4i32 ||
ArgType==MVT::v8i16 || ArgType==MVT::v16i8) {
if (++j > NumVRs) {
- SDOperand PtrOff = DAG.getNode(ISD::ADD, PtrVT, StackPtr,
- DAG.getConstant(ArgOffset, PtrVT));
- SDOperand Store = DAG.getStore(Chain, Arg, PtrOff, NULL, 0);
- MemOpChains.push_back(Store);
+ SDOperand PtrOff;
+ // We are emitting Altivec params in order.
+ LowerMemOpCallTo(DAG, MF, Chain, Arg, PtrOff, SPDiff, ArgOffset,
+ isPPC64, isTailCall, true, MemOpChains,
+ TailCallArguments);
ArgOffset += 16;
}
}
@@ -2120,6 +2415,37 @@
InFlag = Chain.getValue(1);
}
+ // Emit a sequence of copyto/copyfrom virtual registers for arguments that
+ // might overwrite each other in case of tail call optimization.
+ if (isTailCall) {
+ SmallVector<SDOperand, 8> MemOpChains2;
+ // Do not flag preceeding copytoreg stuff together with the following stuff.
+ InFlag = SDOperand();
+ StoreTailCallArgumentsToStackSlot(DAG, Chain, TailCallArguments,
+ MemOpChains2);
+ if (!MemOpChains2.empty())
+ Chain = DAG.getNode(ISD::TokenFactor, MVT::Other,
+ &MemOpChains2[0], MemOpChains2.size());
+
+ // Store the return address to the appropriate stack slot.
+ Chain = EmitTailCallStoreFPAndRetAddr(DAG, MF, Chain, LROp, FPOp, SPDiff,
+ isPPC64, isMachoABI);
+ }
+
+ // Emit callseq_end just before tailcall node.
+ if (isTailCall) {
+ SmallVector<SDOperand, 8> CallSeqOps;
+ SDVTList CallSeqNodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
+ CallSeqOps.push_back(Chain);
+ CallSeqOps.push_back(DAG.getIntPtrConstant(NumBytes));
+ CallSeqOps.push_back(DAG.getIntPtrConstant(0));
+ if (InFlag.Val)
+ CallSeqOps.push_back(InFlag);
+ Chain = DAG.getNode(ISD::CALLSEQ_END, CallSeqNodeTys, &CallSeqOps[0],
+ CallSeqOps.size());
+ InFlag = Chain.getValue(1);
+ }
+
std::vector<MVT::ValueType> NodeTys;
NodeTys.push_back(MVT::Other); // Returns a chain
NodeTys.push_back(MVT::Flag); // Returns a flag for retval copy to use.
@@ -2157,6 +2483,9 @@
Ops.push_back(Chain);
CallOpc = isMachoABI ? PPCISD::BCTRL_Macho : PPCISD::BCTRL_ELF;
Callee.Val = 0;
+ // Add CTR register as callee so a bctr can be emitted later.
+ if (isTailCall)
+ Ops.push_back(DAG.getRegister(PPC::CTR, getPointerTy()));
}
// If this is a direct call, pass the chain and the callee.
@@ -2164,29 +2493,48 @@
Ops.push_back(Chain);
Ops.push_back(Callee);
}
-
+ // If this is a tail call add stack pointer delta.
+ if (isTailCall)
+ Ops.push_back(DAG.getConstant(SPDiff, MVT::i32));
+
// Add argument registers to the end of the list so that they are known live
// into the call.
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
Ops.push_back(DAG.getRegister(RegsToPass[i].first,
RegsToPass[i].second.getValueType()));
-
+
+ // When performing tail call optimization the callee pops its arguments off
+ // the stack. Account for this here so these bytes can be pushed back on in
+ // PPCRegisterInfo::eliminateCallFramePseudoInstr.
+ int BytesCalleePops =
+ (CC==CallingConv::Fast && PerformTailCallOpt) ? NumBytes : 0;
+
if (InFlag.Val)
Ops.push_back(InFlag);
+
+ // Emit tail call.
+ if (isTailCall) {
+ assert(InFlag.Val &&
+ "Flag must be set. Depend on flag being set in LowerRET");
+ Chain = DAG.getNode(PPCISD::TAILCALL,
+ Op.Val->getVTList(), &Ops[0], Ops.size());
+ return SDOperand(Chain.Val, Op.ResNo);
+ }
+
Chain = DAG.getNode(CallOpc, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
Chain = DAG.getCALLSEQ_END(Chain,
DAG.getConstant(NumBytes, PtrVT),
- DAG.getConstant(0, PtrVT),
+ DAG.getConstant(BytesCalleePops, PtrVT),
InFlag);
if (Op.Val->getValueType(0) != MVT::Other)
InFlag = Chain.getValue(1);
SmallVector<SDOperand, 16> ResultVals;
SmallVector<CCValAssign, 16> RVLocs;
- unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
- CCState CCInfo(CC, isVarArg, TM, RVLocs);
+ unsigned CallerCC = DAG.getMachineFunction().getFunction()->getCallingConv();
+ CCState CCInfo(CallerCC, isVarArg, TM, RVLocs);
CCInfo.AnalyzeCallResult(Op.Val, RetCC_PPC);
// Copy all of the result registers out of their specified physreg.
@@ -2226,6 +2574,36 @@
}
SDOperand Chain = Op.getOperand(0);
+
+ Chain = GetPossiblePreceedingTailCall(Chain, PPCISD::TAILCALL);
+ if (Chain.getOpcode() == PPCISD::TAILCALL) {
+ SDOperand TailCall = Chain;
+ SDOperand TargetAddress = TailCall.getOperand(1);
+ SDOperand StackAdjustment = TailCall.getOperand(2);
+
+ assert(((TargetAddress.getOpcode() == ISD::Register &&
+ cast<RegisterSDNode>(TargetAddress)->getReg() == PPC::CTR) ||
+ TargetAddress.getOpcode() == ISD::TargetExternalSymbol ||
+ TargetAddress.getOpcode() == ISD::TargetGlobalAddress ||
+ isa<ConstantSDNode>(TargetAddress)) &&
+ "Expecting an global address, external symbol, absolute value or register");
+
+ assert(StackAdjustment.getOpcode() == ISD::Constant &&
+ "Expecting a const value");
+
+ SmallVector<SDOperand,8> Operands;
+ Operands.push_back(Chain.getOperand(0));
+ Operands.push_back(TargetAddress);
+ Operands.push_back(StackAdjustment);
+ // Copy registers used by the call. Last operand is a flag so it is not
+ // copied.
+ for (unsigned i=3; i < TailCall.getNumOperands()-1; i++) {
+ Operands.push_back(Chain.getOperand(i));
+ }
+ return DAG.getNode(PPCISD::TC_RETURN, MVT::Other, &Operands[0],
+ Operands.size());
+ }
+
SDOperand Flag;
// Copy the result values into the output registers.
@@ -2268,18 +2646,44 @@
return DAG.getStore(Chain, LoadLinkSP, StackPtr, NULL, 0);
}
-SDOperand PPCTargetLowering::LowerDYNAMIC_STACKALLOC(SDOperand Op,
- SelectionDAG &DAG,
- const PPCSubtarget &Subtarget) {
+
+
+SDOperand
+PPCTargetLowering::getReturnAddrFrameIndex(SelectionDAG & DAG) const {
MachineFunction &MF = DAG.getMachineFunction();
- bool IsPPC64 = Subtarget.isPPC64();
- bool isMachoABI = Subtarget.isMachoABI();
+ bool IsPPC64 = PPCSubTarget.isPPC64();
+ bool isMachoABI = PPCSubTarget.isMachoABI();
+ MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+
+ // Get current frame pointer save index. The users of this index will be
+ // primarily DYNALLOC instructions.
+ PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+ int RASI = FI->getReturnAddrSaveIndex();
+
+ // If the frame pointer save index hasn't been defined yet.
+ if (!RASI) {
+ // Find out what the fix offset of the frame pointer save area.
+ int LROffset = PPCFrameInfo::getReturnSaveOffset(IsPPC64, isMachoABI);
+ // Allocate the frame index for frame pointer save area.
+ RASI = MF.getFrameInfo()->CreateFixedObject(IsPPC64? 8 : 4, LROffset);
+ // Save the result.
+ FI->setReturnAddrSaveIndex(RASI);
+ }
+ return DAG.getFrameIndex(RASI, PtrVT);
+}
+
+SDOperand
+PPCTargetLowering::getFramePointerFrameIndex(SelectionDAG & DAG) const {
+ MachineFunction &MF = DAG.getMachineFunction();
+ bool IsPPC64 = PPCSubTarget.isPPC64();
+ bool isMachoABI = PPCSubTarget.isMachoABI();
+ MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
// Get current frame pointer save index. The users of this index will be
// primarily DYNALLOC instructions.
PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
int FPSI = FI->getFramePointerSaveIndex();
-
+
// If the frame pointer save index hasn't been defined yet.
if (!FPSI) {
// Find out what the fix offset of the frame pointer save area.
@@ -2290,7 +2694,12 @@
// Save the result.
FI->setFramePointerSaveIndex(FPSI);
}
+ return DAG.getFrameIndex(FPSI, PtrVT);
+}
+SDOperand PPCTargetLowering::LowerDYNAMIC_STACKALLOC(SDOperand Op,
+ SelectionDAG &DAG,
+ const PPCSubtarget &Subtarget) {
// Get the inputs.
SDOperand Chain = Op.getOperand(0);
SDOperand Size = Op.getOperand(1);
@@ -2301,7 +2710,7 @@
SDOperand NegSize = DAG.getNode(ISD::SUB, PtrVT,
DAG.getConstant(0, PtrVT), Size);
// Construct a node for the frame pointer save index.
- SDOperand FPSIdx = DAG.getFrameIndex(FPSI, PtrVT);
+ SDOperand FPSIdx = getFramePointerFrameIndex(DAG);
// Build a DYNALLOC node.
SDOperand Ops[3] = { Chain, NegSize, FPSIdx };
SDVTList VTs = DAG.getVTList(PtrVT, MVT::Other);
@@ -4099,25 +4508,13 @@
MachineFunction &MF = DAG.getMachineFunction();
PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
- int RAIdx = FuncInfo->getReturnAddrSaveIndex();
- if (RAIdx == 0) {
- bool isPPC64 = PPCSubTarget.isPPC64();
- int Offset =
- PPCFrameInfo::getReturnSaveOffset(isPPC64, PPCSubTarget.isMachoABI());
- // Set up a frame object for the return address.
- RAIdx = MF.getFrameInfo()->CreateFixedObject(isPPC64 ? 8 : 4, Offset);
-
- // Remember it for next time.
- FuncInfo->setReturnAddrSaveIndex(RAIdx);
-
- // Make sure the function really does not optimize away the store of the RA
- // to the stack.
- FuncInfo->setLRStoreRequired();
- }
-
// Just load the return address off the stack.
- SDOperand RetAddrFI = DAG.getFrameIndex(RAIdx, getPointerTy());
+ SDOperand RetAddrFI = getReturnAddrFrameIndex(DAG);
+
+ // Make sure the function really does not optimize away the store of the RA
+ // to the stack.
+ FuncInfo->setLRStoreRequired();
return DAG.getLoad(getPointerTy(), DAG.getEntryNode(), RetAddrFI, NULL, 0);
}