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llvm-6502/lib/Target/PowerPC/PPCISelLowering.cpp
Nate Begeman 4a95945fa5 Add the ability to lower return instructions to TargetLowering. This 
allows us to lower legal return types to something else, to meet ABI
requirements (such as that i64 be returned in two i32 regs on Darwin/ppc).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23802 91177308-0d34-0410-b5e6-96231b3b80d8
2005-10-18 23:23:37 +00:00

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//===-- PPCISelLowering.cpp - PPC DAG Lowering Implementation -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the PPCISelLowering class.
//
//===----------------------------------------------------------------------===//
#include "PPCISelLowering.h"
#include "PPCTargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
using namespace llvm;
PPCTargetLowering::PPCTargetLowering(TargetMachine &TM)
: TargetLowering(TM) {
// Fold away setcc operations if possible.
setSetCCIsExpensive();
// Use _setjmp/_longjmp instead of setjmp/longjmp.
setUseUnderscoreSetJmpLongJmp(true);
// Set up the register classes.
addRegisterClass(MVT::i32, PPC::GPRCRegisterClass);
addRegisterClass(MVT::f32, PPC::F4RCRegisterClass);
addRegisterClass(MVT::f64, PPC::F8RCRegisterClass);
// PowerPC has no intrinsics for these particular operations
setOperationAction(ISD::MEMMOVE, MVT::Other, Expand);
setOperationAction(ISD::MEMSET, MVT::Other, Expand);
setOperationAction(ISD::MEMCPY, MVT::Other, Expand);
// PowerPC has an i16 but no i8 (or i1) SEXTLOAD
setOperationAction(ISD::SEXTLOAD, MVT::i1, Expand);
setOperationAction(ISD::SEXTLOAD, MVT::i8, Expand);
// PowerPC has no SREM/UREM instructions
setOperationAction(ISD::SREM, MVT::i32, Expand);
setOperationAction(ISD::UREM, MVT::i32, Expand);
// We don't support sin/cos/sqrt/fmod
setOperationAction(ISD::FSIN , MVT::f64, Expand);
setOperationAction(ISD::FCOS , MVT::f64, Expand);
setOperationAction(ISD::FREM , MVT::f64, Expand);
setOperationAction(ISD::FSIN , MVT::f32, Expand);
setOperationAction(ISD::FCOS , MVT::f32, Expand);
setOperationAction(ISD::FREM , MVT::f32, Expand);
// If we're enabling GP optimizations, use hardware square root
if (!TM.getSubtarget<PPCSubtarget>().hasFSQRT()) {
setOperationAction(ISD::FSQRT, MVT::f64, Expand);
setOperationAction(ISD::FSQRT, MVT::f32, Expand);
}
// PowerPC does not have CTPOP or CTTZ
setOperationAction(ISD::CTPOP, MVT::i32 , Expand);
setOperationAction(ISD::CTTZ , MVT::i32 , Expand);
// PowerPC does not have Select
setOperationAction(ISD::SELECT, MVT::i32, Expand);
setOperationAction(ISD::SELECT, MVT::f32, Expand);
setOperationAction(ISD::SELECT, MVT::f64, Expand);
// PowerPC wants to turn select_cc of FP into fsel when possible.
setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
setOperationAction(ISD::SELECT_CC, MVT::f64, Custom);
// PowerPC does not have BRCOND* which requires SetCC
setOperationAction(ISD::BRCOND, MVT::Other, Expand);
setOperationAction(ISD::BRCONDTWOWAY, MVT::Other, Expand);
// PowerPC does not have FP_TO_UINT
setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
// PowerPC turns FP_TO_SINT into FCTIWZ and some load/stores.
setOperationAction(ISD::FP_TO_SINT, MVT::i32, Custom);
// PowerPC does not have [U|S]INT_TO_FP
setOperationAction(ISD::SINT_TO_FP, MVT::i32, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
// PowerPC does not have truncstore for i1.
setOperationAction(ISD::TRUNCSTORE, MVT::i1, Promote);
if (TM.getSubtarget<PPCSubtarget>().is64Bit()) {
// They also have instructions for converting between i64 and fp.
setOperationAction(ISD::FP_TO_SINT, MVT::i64, Custom);
setOperationAction(ISD::SINT_TO_FP, MVT::i64, Custom);
}
if (TM.getSubtarget<PPCSubtarget>().has64BitRegs()) {
// 64 bit PowerPC implementations can support i64 types directly
addRegisterClass(MVT::i64, PPC::G8RCRegisterClass);
// BUILD_PAIR can't be handled natively, and should be expanded to shl/or
setOperationAction(ISD::BUILD_PAIR, MVT::i64, Expand);
} else {
// 32 bit PowerPC wants to expand i64 shifts itself.
setOperationAction(ISD::SHL, MVT::i64, Custom);
setOperationAction(ISD::SRL, MVT::i64, Custom);
setOperationAction(ISD::SRA, MVT::i64, Custom);
}
setSetCCResultContents(ZeroOrOneSetCCResult);
computeRegisterProperties();
}
/// isFloatingPointZero - Return true if this is 0.0 or -0.0.
static bool isFloatingPointZero(SDOperand Op) {
if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Op))
return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0);
else if (Op.getOpcode() == ISD::EXTLOAD || Op.getOpcode() == ISD::LOAD) {
// Maybe this has already been legalized into the constant pool?
if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op.getOperand(1)))
if (ConstantFP *CFP = dyn_cast<ConstantFP>(CP->get()))
return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0);
}
return false;
}
/// LowerOperation - Provide custom lowering hooks for some operations.
///
SDOperand PPCTargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
switch (Op.getOpcode()) {
default: assert(0 && "Wasn't expecting to be able to lower this!");
case ISD::FP_TO_SINT: {
assert(MVT::isFloatingPoint(Op.getOperand(0).getValueType()));
SDOperand Src = Op.getOperand(0);
if (Src.getValueType() == MVT::f32)
Src = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Src);
switch (Op.getValueType()) {
default: assert(0 && "Unhandled FP_TO_SINT type in custom expander!");
case MVT::i32:
Op = DAG.getNode(PPCISD::FCTIWZ, MVT::f64, Src);
break;
case MVT::i64:
Op = DAG.getNode(PPCISD::FCTIDZ, MVT::f64, Src);
break;
}
int FrameIdx =
DAG.getMachineFunction().getFrameInfo()->CreateStackObject(8, 8);
SDOperand FI = DAG.getFrameIndex(FrameIdx, MVT::i32);
SDOperand ST = DAG.getNode(ISD::STORE, MVT::Other, DAG.getEntryNode(),
Op, FI, DAG.getSrcValue(0));
if (Op.getOpcode() == PPCISD::FCTIDZ) {
Op = DAG.getLoad(MVT::i64, ST, FI, DAG.getSrcValue(0));
} else {
FI = DAG.getNode(ISD::ADD, MVT::i32, FI, DAG.getConstant(4, MVT::i32));
Op = DAG.getLoad(MVT::i32, ST, FI, DAG.getSrcValue(0));
}
return Op;
}
case ISD::SINT_TO_FP: {
assert(MVT::i64 == Op.getOperand(0).getValueType() &&
"Unhandled SINT_TO_FP type in custom expander!");
int FrameIdx =
DAG.getMachineFunction().getFrameInfo()->CreateStackObject(8, 8);
SDOperand FI = DAG.getFrameIndex(FrameIdx, MVT::i32);
SDOperand ST = DAG.getNode(ISD::STORE, MVT::Other, DAG.getEntryNode(),
Op.getOperand(0), FI, DAG.getSrcValue(0));
SDOperand LD = DAG.getLoad(MVT::f64, ST, FI, DAG.getSrcValue(0));
SDOperand FP = DAG.getNode(PPCISD::FCFID, MVT::f64, LD);
if (MVT::f32 == Op.getValueType())
FP = DAG.getNode(ISD::FP_ROUND, MVT::f32, FP);
return FP;
}
case ISD::SELECT_CC: {
// Turn FP only select_cc's into fsel instructions.
if (!MVT::isFloatingPoint(Op.getOperand(0).getValueType()) ||
!MVT::isFloatingPoint(Op.getOperand(2).getValueType()))
break;
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
// Cannot handle SETEQ/SETNE.
if (CC == ISD::SETEQ || CC == ISD::SETNE) break;
MVT::ValueType ResVT = Op.getValueType();
MVT::ValueType CmpVT = Op.getOperand(0).getValueType();
SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1);
SDOperand TV = Op.getOperand(2), FV = Op.getOperand(3);
// If the RHS of the comparison is a 0.0, we don't need to do the
// subtraction at all.
if (isFloatingPointZero(RHS))
switch (CC) {
default: assert(0 && "Invalid FSEL condition"); abort();
case ISD::SETULT:
case ISD::SETLT:
std::swap(TV, FV); // fsel is natively setge, swap operands for setlt
case ISD::SETUGE:
case ISD::SETGE:
return DAG.getNode(PPCISD::FSEL, ResVT, LHS, TV, FV);
case ISD::SETUGT:
case ISD::SETGT:
std::swap(TV, FV); // fsel is natively setge, swap operands for setlt
case ISD::SETULE:
case ISD::SETLE:
return DAG.getNode(PPCISD::FSEL, ResVT,
DAG.getNode(ISD::FNEG, ResVT, LHS), TV, FV);
}
switch (CC) {
default: assert(0 && "Invalid FSEL condition"); abort();
case ISD::SETULT:
case ISD::SETLT:
return DAG.getNode(PPCISD::FSEL, ResVT,
DAG.getNode(ISD::FSUB, CmpVT, LHS, RHS), FV, TV);
case ISD::SETUGE:
case ISD::SETGE:
return DAG.getNode(PPCISD::FSEL, ResVT,
DAG.getNode(ISD::FSUB, CmpVT, LHS, RHS), TV, FV);
case ISD::SETUGT:
case ISD::SETGT:
return DAG.getNode(PPCISD::FSEL, ResVT,
DAG.getNode(ISD::FSUB, CmpVT, RHS, LHS), FV, TV);
case ISD::SETULE:
case ISD::SETLE:
return DAG.getNode(PPCISD::FSEL, ResVT,
DAG.getNode(ISD::FSUB, CmpVT, RHS, LHS), TV, FV);
}
break;
}
case ISD::SHL: {
assert(Op.getValueType() == MVT::i64 &&
Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SHL!");
// The generic code does a fine job expanding shift by a constant.
if (isa<ConstantSDNode>(Op.getOperand(1))) break;
// Otherwise, expand into a bunch of logical ops. Note that these ops
// depend on the PPC behavior for oversized shift amounts.
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(0, MVT::i32));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(1, MVT::i32));
SDOperand Amt = Op.getOperand(1);
SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
DAG.getConstant(32, MVT::i32), Amt);
SDOperand Tmp2 = DAG.getNode(ISD::SHL, MVT::i32, Hi, Amt);
SDOperand Tmp3 = DAG.getNode(ISD::SRL, MVT::i32, Lo, Tmp1);
SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
DAG.getConstant(-32U, MVT::i32));
SDOperand Tmp6 = DAG.getNode(ISD::SHL, MVT::i32, Lo, Tmp5);
SDOperand OutHi = DAG.getNode(ISD::OR, MVT::i32, Tmp4, Tmp6);
SDOperand OutLo = DAG.getNode(ISD::SHL, MVT::i32, Lo, Amt);
return DAG.getNode(ISD::BUILD_PAIR, MVT::i64, OutLo, OutHi);
}
case ISD::SRL: {
assert(Op.getValueType() == MVT::i64 &&
Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SHL!");
// The generic code does a fine job expanding shift by a constant.
if (isa<ConstantSDNode>(Op.getOperand(1))) break;
// Otherwise, expand into a bunch of logical ops. Note that these ops
// depend on the PPC behavior for oversized shift amounts.
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(0, MVT::i32));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(1, MVT::i32));
SDOperand Amt = Op.getOperand(1);
SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
DAG.getConstant(32, MVT::i32), Amt);
SDOperand Tmp2 = DAG.getNode(ISD::SRL, MVT::i32, Lo, Amt);
SDOperand Tmp3 = DAG.getNode(ISD::SHL, MVT::i32, Hi, Tmp1);
SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
DAG.getConstant(-32U, MVT::i32));
SDOperand Tmp6 = DAG.getNode(ISD::SRL, MVT::i32, Hi, Tmp5);
SDOperand OutLo = DAG.getNode(ISD::OR, MVT::i32, Tmp4, Tmp6);
SDOperand OutHi = DAG.getNode(ISD::SRL, MVT::i32, Hi, Amt);
return DAG.getNode(ISD::BUILD_PAIR, MVT::i64, OutLo, OutHi);
}
case ISD::SRA: {
assert(Op.getValueType() == MVT::i64 &&
Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SRA!");
// The generic code does a fine job expanding shift by a constant.
if (isa<ConstantSDNode>(Op.getOperand(1))) break;
// Otherwise, expand into a bunch of logical ops, followed by a select_cc.
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(0, MVT::i32));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op.getOperand(0),
DAG.getConstant(1, MVT::i32));
SDOperand Amt = Op.getOperand(1);
SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
DAG.getConstant(32, MVT::i32), Amt);
SDOperand Tmp2 = DAG.getNode(ISD::SRL, MVT::i32, Lo, Amt);
SDOperand Tmp3 = DAG.getNode(ISD::SHL, MVT::i32, Hi, Tmp1);
SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
DAG.getConstant(-32U, MVT::i32));
SDOperand Tmp6 = DAG.getNode(ISD::SRA, MVT::i32, Hi, Tmp5);
SDOperand OutHi = DAG.getNode(ISD::SRA, MVT::i32, Hi, Amt);
SDOperand OutLo = DAG.getSelectCC(Tmp5, DAG.getConstant(0, MVT::i32),
Tmp4, Tmp6, ISD::SETLE);
return DAG.getNode(ISD::BUILD_PAIR, MVT::i64, OutLo, OutHi);
}
}
return SDOperand();
}
std::vector<SDOperand>
PPCTargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
//
// add beautiful description of PPC stack frame format, or at least some docs
//
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock& BB = MF.front();
SSARegMap *RegMap = MF.getSSARegMap();
std::vector<SDOperand> ArgValues;
unsigned ArgOffset = 24;
unsigned GPR_remaining = 8;
unsigned FPR_remaining = 13;
unsigned GPR_idx = 0, FPR_idx = 0;
static const unsigned GPR[] = {
PPC::R3, PPC::R4, PPC::R5, PPC::R6,
PPC::R7, PPC::R8, PPC::R9, PPC::R10,
};
static const unsigned FPR[] = {
PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13
};
// Add DAG nodes to load the arguments... On entry to a function on PPC,
// the arguments start at offset 24, although they are likely to be passed
// in registers.
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) {
SDOperand newroot, argt;
unsigned ObjSize;
bool needsLoad = false;
bool ArgLive = !I->use_empty();
MVT::ValueType ObjectVT = getValueType(I->getType());
switch (ObjectVT) {
default: assert(0 && "Unhandled argument type!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
ObjSize = 4;
if (!ArgLive) break;
if (GPR_remaining > 0) {
unsigned VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
MF.addLiveIn(GPR[GPR_idx], VReg);
argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), VReg, MVT::i32);
if (ObjectVT != MVT::i32) {
unsigned AssertOp = I->getType()->isSigned() ? ISD::AssertSext
: ISD::AssertZext;
argt = DAG.getNode(AssertOp, MVT::i32, argt,
DAG.getValueType(ObjectVT));
argt = DAG.getNode(ISD::TRUNCATE, ObjectVT, argt);
}
} else {
needsLoad = true;
}
break;
case MVT::i64: ObjSize = 8;
if (!ArgLive) break;
if (GPR_remaining > 0) {
SDOperand argHi, argLo;
unsigned VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
MF.addLiveIn(GPR[GPR_idx], VReg);
argHi = DAG.getCopyFromReg(DAG.getRoot(), VReg, MVT::i32);
// If we have two or more remaining argument registers, then both halves
// of the i64 can be sourced from there. Otherwise, the lower half will
// have to come off the stack. This can happen when an i64 is preceded
// by 28 bytes of arguments.
if (GPR_remaining > 1) {
unsigned VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
MF.addLiveIn(GPR[GPR_idx+1], VReg);
argLo = DAG.getCopyFromReg(argHi, VReg, MVT::i32);
} else {
int FI = MFI->CreateFixedObject(4, ArgOffset+4);
SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32);
argLo = DAG.getLoad(MVT::i32, DAG.getEntryNode(), FIN,
DAG.getSrcValue(NULL));
}
// Build the outgoing arg thingy
argt = DAG.getNode(ISD::BUILD_PAIR, MVT::i64, argLo, argHi);
newroot = argLo;
} else {
needsLoad = true;
}
break;
case MVT::f32:
case MVT::f64:
ObjSize = (ObjectVT == MVT::f64) ? 8 : 4;
if (!ArgLive) break;
if (FPR_remaining > 0) {
unsigned VReg;
if (ObjectVT == MVT::f32)
VReg = RegMap->createVirtualRegister(&PPC::F4RCRegClass);
else
VReg = RegMap->createVirtualRegister(&PPC::F8RCRegClass);
MF.addLiveIn(FPR[FPR_idx], VReg);
argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), VReg, ObjectVT);
--FPR_remaining;
++FPR_idx;
} else {
needsLoad = true;
}
break;
}
// We need to load the argument to a virtual register if we determined above
// that we ran out of physical registers of the appropriate type
if (needsLoad) {
unsigned SubregOffset = 0;
if (ObjectVT == MVT::i8 || ObjectVT == MVT::i1) SubregOffset = 3;
if (ObjectVT == MVT::i16) SubregOffset = 2;
int FI = MFI->CreateFixedObject(ObjSize, ArgOffset);
SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32);
FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN,
DAG.getConstant(SubregOffset, MVT::i32));
argt = newroot = DAG.getLoad(ObjectVT, DAG.getEntryNode(), FIN,
DAG.getSrcValue(NULL));
}
// Every 4 bytes of argument space consumes one of the GPRs available for
// argument passing.
if (GPR_remaining > 0) {
unsigned delta = (GPR_remaining > 1 && ObjSize == 8) ? 2 : 1;
GPR_remaining -= delta;
GPR_idx += delta;
}
ArgOffset += ObjSize;
if (newroot.Val)
DAG.setRoot(newroot.getValue(1));
ArgValues.push_back(argt);
}
// 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 (F.isVarArg()) {
VarArgsFrameIndex = MFI->CreateFixedObject(4, ArgOffset);
SDOperand FIN = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
// If this function is vararg, store any remaining integer argument regs
// to their spots on the stack so that they may be loaded by deferencing the
// result of va_next.
std::vector<SDOperand> MemOps;
for (; GPR_remaining > 0; --GPR_remaining, ++GPR_idx) {
unsigned VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
MF.addLiveIn(GPR[GPR_idx], VReg);
SDOperand Val = DAG.getCopyFromReg(DAG.getRoot(), VReg, MVT::i32);
SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Val.getValue(1),
Val, FIN, DAG.getSrcValue(NULL));
MemOps.push_back(Store);
// Increment the address by four for the next argument to store
SDOperand PtrOff = DAG.getConstant(4, getPointerTy());
FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN, PtrOff);
}
DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps));
}
// Finally, inform the code generator which regs we return values in.
switch (getValueType(F.getReturnType())) {
default: assert(0 && "Unknown type!");
case MVT::isVoid: break;
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
MF.addLiveOut(PPC::R3);
break;
case MVT::i64:
MF.addLiveOut(PPC::R3);
MF.addLiveOut(PPC::R4);
break;
case MVT::f32:
case MVT::f64:
MF.addLiveOut(PPC::F1);
break;
}
return ArgValues;
}
std::pair<SDOperand, SDOperand>
PPCTargetLowering::LowerCallTo(SDOperand Chain,
const Type *RetTy, bool isVarArg,
unsigned CallingConv, bool isTailCall,
SDOperand Callee, ArgListTy &Args,
SelectionDAG &DAG) {
// args_to_use will accumulate outgoing args for the ISD::CALL case in
// SelectExpr to use to put the arguments in the appropriate registers.
std::vector<SDOperand> args_to_use;
// Count how many bytes are to be pushed on the stack, including the linkage
// area, and parameter passing area.
unsigned NumBytes = 24;
if (Args.empty()) {
Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
} else {
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
switch (getValueType(Args[i].second)) {
default: assert(0 && "Unknown value type!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
case MVT::f32:
NumBytes += 4;
break;
case MVT::i64:
case MVT::f64:
NumBytes += 8;
break;
}
}
// Just to be safe, we'll always reserve the full 24 bytes of linkage area
// plus 32 bytes of argument space in case any called code gets funky on us.
// (Required by ABI to support var arg)
if (NumBytes < 56) NumBytes = 56;
// Adjust the stack pointer for the new arguments...
// These operations are automatically eliminated by the prolog/epilog pass
Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
// 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.
SDOperand StackPtr = DAG.getCopyFromReg(DAG.getEntryNode(),
PPC::R1, MVT::i32);
// Figure out which arguments are going to go in registers, and which in
// memory. Also, if this is a vararg function, floating point operations
// must be stored to our stack, and loaded into integer regs as well, if
// any integer regs are available for argument passing.
unsigned ArgOffset = 24;
unsigned GPR_remaining = 8;
unsigned FPR_remaining = 13;
std::vector<SDOperand> MemOps;
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
// PtrOff will be used to store the current argument to the stack if a
// register cannot be found for it.
SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, StackPtr, PtrOff);
MVT::ValueType ArgVT = getValueType(Args[i].second);
switch (ArgVT) {
default: assert(0 && "Unexpected ValueType for argument!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
// Promote the integer to 32 bits. If the input type is signed use a
// sign extend, otherwise use a zero extend.
if (Args[i].second->isSigned())
Args[i].first =DAG.getNode(ISD::SIGN_EXTEND, MVT::i32, Args[i].first);
else
Args[i].first =DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Args[i].first);
// FALL THROUGH
case MVT::i32:
if (GPR_remaining > 0) {
args_to_use.push_back(Args[i].first);
--GPR_remaining;
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += 4;
break;
case MVT::i64:
// If we have one free GPR left, we can place the upper half of the i64
// in it, and store the other half to the stack. If we have two or more
// free GPRs, then we can pass both halves of the i64 in registers.
if (GPR_remaining > 0) {
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32,
Args[i].first, DAG.getConstant(1, MVT::i32));
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32,
Args[i].first, DAG.getConstant(0, MVT::i32));
args_to_use.push_back(Hi);
--GPR_remaining;
if (GPR_remaining > 0) {
args_to_use.push_back(Lo);
--GPR_remaining;
} else {
SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Lo, PtrOff, DAG.getSrcValue(NULL)));
}
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += 8;
break;
case MVT::f32:
case MVT::f64:
if (FPR_remaining > 0) {
args_to_use.push_back(Args[i].first);
--FPR_remaining;
if (isVarArg) {
SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Store);
// Float varargs are always shadowed in available integer registers
if (GPR_remaining > 0) {
SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Load);
args_to_use.push_back(Load);
--GPR_remaining;
}
if (GPR_remaining > 0 && MVT::f64 == ArgVT) {
SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Load);
args_to_use.push_back(Load);
--GPR_remaining;
}
} else {
// If we have any FPRs remaining, we may also have GPRs remaining.
// Args passed in FPRs consume either 1 (f32) or 2 (f64) available
// GPRs.
if (GPR_remaining > 0) {
args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
--GPR_remaining;
}
if (GPR_remaining > 0 && MVT::f64 == ArgVT) {
args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
--GPR_remaining;
}
}
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += (ArgVT == MVT::f32) ? 4 : 8;
break;
}
}
if (!MemOps.empty())
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps);
}
std::vector<MVT::ValueType> RetVals;
MVT::ValueType RetTyVT = getValueType(RetTy);
MVT::ValueType ActualRetTyVT = RetTyVT;
if (RetTyVT >= MVT::i1 && RetTyVT <= MVT::i16)
ActualRetTyVT = MVT::i32; // Promote result to i32.
if (RetTyVT != MVT::isVoid)
RetVals.push_back(ActualRetTyVT);
RetVals.push_back(MVT::Other);
SDOperand TheCall = SDOperand(DAG.getCall(RetVals,
Chain, Callee, args_to_use), 0);
Chain = TheCall.getValue(RetTyVT != MVT::isVoid);
Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
SDOperand RetVal = TheCall;
// If the result is a small value, add a note so that we keep track of the
// information about whether it is sign or zero extended.
if (RetTyVT != ActualRetTyVT) {
RetVal = DAG.getNode(RetTy->isSigned() ? ISD::AssertSext : ISD::AssertZext,
MVT::i32, RetVal, DAG.getValueType(RetTyVT));
RetVal = DAG.getNode(ISD::TRUNCATE, RetTyVT, RetVal);
}
return std::make_pair(RetVal, Chain);
}
SDOperand PPCTargetLowering::LowerReturnTo(SDOperand Chain, SDOperand Op,
SelectionDAG &DAG) {
if (Op.getValueType() == MVT::i64) {
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op,
DAG.getConstant(1, MVT::i32));
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op,
DAG.getConstant(0, MVT::i32));
return DAG.getNode(ISD::RET, MVT::Other, Chain, Lo, Hi);
} else {
return DAG.getNode(ISD::RET, MVT::Other, Chain, Op);
}
}
SDOperand PPCTargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP,
Value *VAListV, SelectionDAG &DAG) {
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
return DAG.getNode(ISD::STORE, MVT::Other, Chain, FR, VAListP,
DAG.getSrcValue(VAListV));
}
std::pair<SDOperand,SDOperand>
PPCTargetLowering::LowerVAArg(SDOperand Chain,
SDOperand VAListP, Value *VAListV,
const Type *ArgTy, SelectionDAG &DAG) {
MVT::ValueType ArgVT = getValueType(ArgTy);
SDOperand VAList =
DAG.getLoad(MVT::i32, Chain, VAListP, DAG.getSrcValue(VAListV));
SDOperand Result = DAG.getLoad(ArgVT, Chain, VAList, DAG.getSrcValue(NULL));
unsigned Amt;
if (ArgVT == MVT::i32 || ArgVT == MVT::f32)
Amt = 4;
else {
assert((ArgVT == MVT::i64 || ArgVT == MVT::f64) &&
"Other types should have been promoted for varargs!");
Amt = 8;
}
VAList = DAG.getNode(ISD::ADD, VAList.getValueType(), VAList,
DAG.getConstant(Amt, VAList.getValueType()));
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain,
VAList, VAListP, DAG.getSrcValue(VAListV));
return std::make_pair(Result, Chain);
}
std::pair<SDOperand, SDOperand> PPCTargetLowering::
LowerFrameReturnAddress(bool isFrameAddress, SDOperand Chain, unsigned Depth,
SelectionDAG &DAG) {
assert(0 && "LowerFrameReturnAddress unimplemented");
abort();
}
MachineBasicBlock *
PPCTargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI,
MachineBasicBlock *BB) {
assert((MI->getOpcode() == PPC::SELECT_CC_Int ||
MI->getOpcode() == PPC::SELECT_CC_F4 ||
MI->getOpcode() == PPC::SELECT_CC_F8) &&
"Unexpected instr type to insert");
// To "insert" a SELECT_CC instruction, we actually have to insert the diamond
// control-flow pattern. The incoming instruction knows the destination vreg
// to set, the condition code register to branch on, the true/false values to
// select between, and a branch opcode to use.
const BasicBlock *LLVM_BB = BB->getBasicBlock();
ilist<MachineBasicBlock>::iterator It = BB;
++It;
// thisMBB:
// ...
// TrueVal = ...
// cmpTY ccX, r1, r2
// bCC copy1MBB
// fallthrough --> copy0MBB
MachineBasicBlock *thisMBB = BB;
MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB);
BuildMI(BB, MI->getOperand(4).getImmedValue(), 2)
.addReg(MI->getOperand(1).getReg()).addMBB(sinkMBB);
MachineFunction *F = BB->getParent();
F->getBasicBlockList().insert(It, copy0MBB);
F->getBasicBlockList().insert(It, sinkMBB);
// Update machine-CFG edges
BB->addSuccessor(copy0MBB);
BB->addSuccessor(sinkMBB);
// copy0MBB:
// %FalseValue = ...
// # fallthrough to sinkMBB
BB = copy0MBB;
// Update machine-CFG edges
BB->addSuccessor(sinkMBB);
// sinkMBB:
// %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
// ...
BB = sinkMBB;
BuildMI(BB, PPC::PHI, 4, MI->getOperand(0).getReg())
.addReg(MI->getOperand(3).getReg()).addMBB(copy0MBB)
.addReg(MI->getOperand(2).getReg()).addMBB(thisMBB);
delete MI; // The pseudo instruction is gone now.
return BB;
}
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