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llvm-6502/lib/Target/IA64/IA64ISelLowering.cpp

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//===-- IA64ISelLowering.cpp - IA64 DAG Lowering Implementation -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the IA64ISelLowering class.
//
//===----------------------------------------------------------------------===//
#include "IA64ISelLowering.h"
#include "IA64MachineFunctionInfo.h"
#include "IA64TargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
using namespace llvm;
IA64TargetLowering::IA64TargetLowering(TargetMachine &TM)
: TargetLowering(TM) {
// register class for general registers
addRegisterClass(MVT::i64, IA64::GRRegisterClass);
// register class for FP registers
addRegisterClass(MVT::f64, IA64::FPRegisterClass);
// register class for predicate registers
addRegisterClass(MVT::i1, IA64::PRRegisterClass);
setLoadXAction(ISD::EXTLOAD , MVT::i1 , Promote);
setLoadXAction(ISD::ZEXTLOAD , MVT::i1 , Promote);
setLoadXAction(ISD::SEXTLOAD , MVT::i1 , Promote);
setLoadXAction(ISD::SEXTLOAD , MVT::i8 , Expand);
setLoadXAction(ISD::SEXTLOAD , MVT::i16 , Expand);
setLoadXAction(ISD::SEXTLOAD , MVT::i32 , Expand);
setOperationAction(ISD::BRIND , MVT::Other, Expand);
setOperationAction(ISD::BR_JT , MVT::Other, Expand);
setOperationAction(ISD::BR_CC , MVT::Other, Expand);
setOperationAction(ISD::FP_ROUND_INREG , MVT::f32 , Expand);
// ia64 uses SELECT not SELECT_CC
setOperationAction(ISD::SELECT_CC , MVT::Other, Expand);
// We need to handle ISD::RET for void functions ourselves,
// so we get a chance to restore ar.pfs before adding a
// br.ret insn
setOperationAction(ISD::RET, MVT::Other, Custom);
setSetCCResultType(MVT::i1);
setShiftAmountType(MVT::i64);
setOperationAction(ISD::FREM , MVT::f32 , Expand);
setOperationAction(ISD::FREM , MVT::f64 , Expand);
setOperationAction(ISD::UREM , MVT::f32 , Expand);
setOperationAction(ISD::UREM , MVT::f64 , Expand);
setOperationAction(ISD::MEMMOVE , MVT::Other, Expand);
setOperationAction(ISD::MEMSET , MVT::Other, Expand);
setOperationAction(ISD::MEMCPY , MVT::Other, Expand);
setOperationAction(ISD::MEMBARRIER , MVT::Other, Expand);
setOperationAction(ISD::SINT_TO_FP , MVT::i1 , Promote);
setOperationAction(ISD::UINT_TO_FP , MVT::i1 , Promote);
// We don't support sin/cos/sqrt/pow
setOperationAction(ISD::FSIN , MVT::f64, Expand);
setOperationAction(ISD::FCOS , MVT::f64, Expand);
setOperationAction(ISD::FSQRT, MVT::f64, Expand);
setOperationAction(ISD::FPOW , MVT::f64, Expand);
setOperationAction(ISD::FSIN , MVT::f32, Expand);
setOperationAction(ISD::FCOS , MVT::f32, Expand);
setOperationAction(ISD::FSQRT, MVT::f32, Expand);
setOperationAction(ISD::FPOW , MVT::f32, Expand);
// FIXME: IA64 supports fcopysign natively!
setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
// We don't have line number support yet.
setOperationAction(ISD::LOCATION, MVT::Other, Expand);
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
setOperationAction(ISD::LABEL, MVT::Other, Expand);
//IA64 has these, but they are not implemented
setOperationAction(ISD::CTTZ , MVT::i64 , Expand);
setOperationAction(ISD::CTLZ , MVT::i64 , Expand);
setOperationAction(ISD::ROTL , MVT::i64 , Expand);
setOperationAction(ISD::ROTR , MVT::i64 , Expand);
setOperationAction(ISD::BSWAP, MVT::i64 , Expand); // mux @rev
// VASTART needs to be custom lowered to use the VarArgsFrameIndex
setOperationAction(ISD::VAARG , MVT::Other, Custom);
setOperationAction(ISD::VASTART , MVT::Other, Custom);
// Use the default implementation.
setOperationAction(ISD::VACOPY , MVT::Other, Expand);
setOperationAction(ISD::VAEND , MVT::Other, Expand);
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64, Expand);
setOperationAction(ISD::PREFETCH , MVT::Other, Expand);
// Thread Local Storage
setOperationAction(ISD::GlobalTLSAddress, MVT::i64, Custom);
setStackPointerRegisterToSaveRestore(IA64::r12);
setJumpBufSize(704); // on ia64-linux, jmp_bufs are 704 bytes..
setJumpBufAlignment(16); // ...and must be 16-byte aligned
computeRegisterProperties();
addLegalFPImmediate(APFloat(+0.0));
addLegalFPImmediate(APFloat(-0.0));
addLegalFPImmediate(APFloat(+1.0));
addLegalFPImmediate(APFloat(-1.0));
}
const char *IA64TargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
default: return 0;
case IA64ISD::GETFD: return "IA64ISD::GETFD";
case IA64ISD::BRCALL: return "IA64ISD::BRCALL";
case IA64ISD::RET_FLAG: return "IA64ISD::RET_FLAG";
}
}
std::vector<SDOperand>
IA64TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
std::vector<SDOperand> ArgValues;
//
// add beautiful description of IA64 stack frame format
// here (from intel 24535803.pdf most likely)
//
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
GP = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
SP = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
RP = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
MachineBasicBlock& BB = MF.front();
unsigned args_int[] = {IA64::r32, IA64::r33, IA64::r34, IA64::r35,
IA64::r36, IA64::r37, IA64::r38, IA64::r39};
unsigned args_FP[] = {IA64::F8, IA64::F9, IA64::F10, IA64::F11,
IA64::F12,IA64::F13,IA64::F14, IA64::F15};
unsigned argVreg[8];
unsigned argPreg[8];
unsigned argOpc[8];
unsigned used_FPArgs = 0; // how many FP args have been used so far?
unsigned ArgOffset = 0;
int count = 0;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
{
SDOperand newroot, argt;
if(count < 8) { // need to fix this logic? maybe.
switch (getValueType(I->getType())) {
default:
assert(0 && "ERROR in LowerArgs: can't lower this type of arg.\n");
case MVT::f32:
// fixme? (well, will need to for weird FP structy stuff,
// see intel ABI docs)
case MVT::f64:
//XXX BuildMI(&BB, IA64::IDEF, 0, args_FP[used_FPArgs]);
MF.getRegInfo().addLiveIn(args_FP[used_FPArgs]);
// mark this reg as liveIn
// floating point args go into f8..f15 as-needed, the increment
argVreg[count] = // is below..:
MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::f64));
// FP args go into f8..f15 as needed: (hence the ++)
argPreg[count] = args_FP[used_FPArgs++];
argOpc[count] = IA64::FMOV;
argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), argVreg[count],
MVT::f64);
if (I->getType() == Type::FloatTy)
argt = DAG.getNode(ISD::FP_ROUND, MVT::f32, argt,
DAG.getIntPtrConstant(0));
break;
case MVT::i1: // NOTE: as far as C abi stuff goes,
// bools are just boring old ints
case MVT::i8:
case MVT::i16:
case MVT::i32:
case MVT::i64:
//XXX BuildMI(&BB, IA64::IDEF, 0, args_int[count]);
MF.getRegInfo().addLiveIn(args_int[count]);
// mark this register as liveIn
argVreg[count] =
MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
argPreg[count] = args_int[count];
argOpc[count] = IA64::MOV;
argt = newroot =
DAG.getCopyFromReg(DAG.getRoot(), argVreg[count], MVT::i64);
if ( getValueType(I->getType()) != MVT::i64)
argt = DAG.getNode(ISD::TRUNCATE, getValueType(I->getType()),
newroot);
break;
}
} else { // more than 8 args go into the frame
// Create the frame index object for this incoming parameter...
ArgOffset = 16 + 8 * (count - 8);
int FI = MFI->CreateFixedObject(8, ArgOffset);
// Create the SelectionDAG nodes corresponding to a load
//from this parameter
SDOperand FIN = DAG.getFrameIndex(FI, MVT::i64);
argt = newroot = DAG.getLoad(getValueType(I->getType()),
DAG.getEntryNode(), FIN, NULL, 0);
}
++count;
DAG.setRoot(newroot.getValue(1));
ArgValues.push_back(argt);
}
// Create a vreg to hold the output of (what will become)
// the "alloc" instruction
VirtGPR = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
BuildMI(&BB, TII->get(IA64::PSEUDO_ALLOC), VirtGPR);
// we create a PSEUDO_ALLOC (pseudo)instruction for now
/*
BuildMI(&BB, IA64::IDEF, 0, IA64::r1);
// hmm:
BuildMI(&BB, IA64::IDEF, 0, IA64::r12);
BuildMI(&BB, IA64::IDEF, 0, IA64::rp);
// ..hmm.
BuildMI(&BB, IA64::MOV, 1, GP).addReg(IA64::r1);
// hmm:
BuildMI(&BB, IA64::MOV, 1, SP).addReg(IA64::r12);
BuildMI(&BB, IA64::MOV, 1, RP).addReg(IA64::rp);
// ..hmm.
*/
unsigned tempOffset=0;
// if this is a varargs function, we simply lower llvm.va_start by
// pointing to the first entry
if(F.isVarArg()) {
tempOffset=0;
VarArgsFrameIndex = MFI->CreateFixedObject(8, tempOffset);
}
// here we actually do the moving of args, and store them to the stack
// too if this is a varargs function:
for (int i = 0; i < count && i < 8; ++i) {
BuildMI(&BB, TII->get(argOpc[i]), argVreg[i]).addReg(argPreg[i]);
if(F.isVarArg()) {
// if this is a varargs function, we copy the input registers to the stack
int FI = MFI->CreateFixedObject(8, tempOffset);
tempOffset+=8; //XXX: is it safe to use r22 like this?
BuildMI(&BB, TII->get(IA64::MOV), IA64::r22).addFrameIndex(FI);
// FIXME: we should use st8.spill here, one day
BuildMI(&BB, TII->get(IA64::ST8), IA64::r22).addReg(argPreg[i]);
}
}
// Finally, inform the code generator which regs we return values in.
// (see the ISD::RET: case in the instruction selector)
switch (getValueType(F.getReturnType())) {
default: assert(0 && "i have no idea where to return this type!");
case MVT::isVoid: break;
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
case MVT::i64:
MF.getRegInfo().addLiveOut(IA64::r8);
break;
case MVT::f32:
case MVT::f64:
MF.getRegInfo().addLiveOut(IA64::F8);
break;
}
return ArgValues;
}
std::pair<SDOperand, SDOperand>
IA64TargetLowering::LowerCallTo(SDOperand Chain, const Type *RetTy,
bool RetSExt, bool RetZExt,
bool isVarArg, unsigned CallingConv,
bool isTailCall, SDOperand Callee,
ArgListTy &Args, SelectionDAG &DAG) {
MachineFunction &MF = DAG.getMachineFunction();
unsigned NumBytes = 16;
unsigned outRegsUsed = 0;
if (Args.size() > 8) {
NumBytes += (Args.size() - 8) * 8;
outRegsUsed = 8;
} else {
outRegsUsed = Args.size();
}
// FIXME? this WILL fail if we ever try to pass around an arg that
// consumes more than a single output slot (a 'real' double, int128
// some sort of aggregate etc.), as we'll underestimate how many 'outX'
// registers we use. Hopefully, the assembler will notice.
MF.getInfo<IA64FunctionInfo>()->outRegsUsed=
std::max(outRegsUsed, MF.getInfo<IA64FunctionInfo>()->outRegsUsed);
// keep stack frame 16-byte aligned
// assert(NumBytes==((NumBytes+15) & ~15) &&
// "stack frame not 16-byte aligned!");
NumBytes = (NumBytes+15) & ~15;
Chain = DAG.getCALLSEQ_START(Chain,DAG.getConstant(NumBytes, getPointerTy()));
SDOperand StackPtr;
std::vector<SDOperand> Stores;
std::vector<SDOperand> Converts;
std::vector<SDOperand> RegValuesToPass;
unsigned ArgOffset = 16;
for (unsigned i = 0, e = Args.size(); i != e; ++i)
{
SDOperand Val = Args[i].Node;
MVT::ValueType ObjectVT = Val.getValueType();
SDOperand ValToStore(0, 0), ValToConvert(0, 0);
unsigned ObjSize=8;
switch (ObjectVT) {
default: assert(0 && "unexpected argument type!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32: {
//promote to 64-bits, sign/zero extending based on type
//of the argument
ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
if (Args[i].isSExt)
ExtendKind = ISD::SIGN_EXTEND;
else if (Args[i].isZExt)
ExtendKind = ISD::ZERO_EXTEND;
Val = DAG.getNode(ExtendKind, MVT::i64, Val);
// XXX: fall through
}
case MVT::i64:
//ObjSize = 8;
if(RegValuesToPass.size() >= 8) {
ValToStore = Val;
} else {
RegValuesToPass.push_back(Val);
}
break;
case MVT::f32:
//promote to 64-bits
Val = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Val);
// XXX: fall through
case MVT::f64:
if(RegValuesToPass.size() >= 8) {
ValToStore = Val;
} else {
RegValuesToPass.push_back(Val);
if(1 /* TODO: if(calling external or varadic function)*/ ) {
ValToConvert = Val; // additionally pass this FP value as an int
}
}
break;
}
if(ValToStore.Val) {
if(!StackPtr.Val) {
StackPtr = DAG.getRegister(IA64::r12, MVT::i64);
}
SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i64, StackPtr, PtrOff);
Stores.push_back(DAG.getStore(Chain, ValToStore, PtrOff, NULL, 0));
ArgOffset += ObjSize;
}
if(ValToConvert.Val) {
Converts.push_back(DAG.getNode(IA64ISD::GETFD, MVT::i64, ValToConvert));
}
}
// Emit all stores, make sure they occur before any copies into physregs.
if (!Stores.empty())
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &Stores[0],Stores.size());
static const unsigned IntArgRegs[] = {
IA64::out0, IA64::out1, IA64::out2, IA64::out3,
IA64::out4, IA64::out5, IA64::out6, IA64::out7
};
static const unsigned FPArgRegs[] = {
IA64::F8, IA64::F9, IA64::F10, IA64::F11,
IA64::F12, IA64::F13, IA64::F14, IA64::F15
};
SDOperand InFlag;
// save the current GP, SP and RP : FIXME: do we need to do all 3 always?
SDOperand GPBeforeCall = DAG.getCopyFromReg(Chain, IA64::r1, MVT::i64, InFlag);
Chain = GPBeforeCall.getValue(1);
InFlag = Chain.getValue(2);
SDOperand SPBeforeCall = DAG.getCopyFromReg(Chain, IA64::r12, MVT::i64, InFlag);
Chain = SPBeforeCall.getValue(1);
InFlag = Chain.getValue(2);
SDOperand RPBeforeCall = DAG.getCopyFromReg(Chain, IA64::rp, MVT::i64, InFlag);
Chain = RPBeforeCall.getValue(1);
InFlag = Chain.getValue(2);
// Build a sequence of copy-to-reg nodes chained together with token chain
// and flag operands which copy the outgoing integer args into regs out[0-7]
// mapped 1:1 and the FP args into regs F8-F15 "lazily"
// TODO: for performance, we should only copy FP args into int regs when we
// know this is required (i.e. for varardic or external (unknown) functions)
// first to the FP->(integer representation) conversions, these are
// flagged for now, but shouldn't have to be (TODO)
unsigned seenConverts = 0;
for (unsigned i = 0, e = RegValuesToPass.size(); i != e; ++i) {
if(MVT::isFloatingPoint(RegValuesToPass[i].getValueType())) {
Chain = DAG.getCopyToReg(Chain, IntArgRegs[i], Converts[seenConverts++],
InFlag);
InFlag = Chain.getValue(1);
}
}
// next copy args into the usual places, these are flagged
unsigned usedFPArgs = 0;
for (unsigned i = 0, e = RegValuesToPass.size(); i != e; ++i) {
Chain = DAG.getCopyToReg(Chain,
MVT::isInteger(RegValuesToPass[i].getValueType()) ?
IntArgRegs[i] : FPArgRegs[usedFPArgs++], RegValuesToPass[i], InFlag);
InFlag = Chain.getValue(1);
}
// If the callee is a GlobalAddress node (quite common, every direct call is)
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
/*
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i64);
}
*/
std::vector<MVT::ValueType> NodeTys;
std::vector<SDOperand> CallOperands;
NodeTys.push_back(MVT::Other); // Returns a chain
NodeTys.push_back(MVT::Flag); // Returns a flag for retval copy to use.
CallOperands.push_back(Chain);
CallOperands.push_back(Callee);
// emit the call itself
if (InFlag.Val)
CallOperands.push_back(InFlag);
else
assert(0 && "this should never happen!\n");
// to make way for a hack:
Chain = DAG.getNode(IA64ISD::BRCALL, NodeTys,
&CallOperands[0], CallOperands.size());
InFlag = Chain.getValue(1);
// restore the GP, SP and RP after the call
Chain = DAG.getCopyToReg(Chain, IA64::r1, GPBeforeCall, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, IA64::r12, SPBeforeCall, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, IA64::rp, RPBeforeCall, InFlag);
InFlag = Chain.getValue(1);
std::vector<MVT::ValueType> RetVals;
RetVals.push_back(MVT::Other);
RetVals.push_back(MVT::Flag);
MVT::ValueType RetTyVT = getValueType(RetTy);
SDOperand RetVal;
if (RetTyVT != MVT::isVoid) {
switch (RetTyVT) {
default: assert(0 && "Unknown value type to return!");
case MVT::i1: { // bools are just like other integers (returned in r8)
// we *could* fall through to the truncate below, but this saves a
// few redundant predicate ops
SDOperand boolInR8 = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64,InFlag);
InFlag = boolInR8.getValue(2);
Chain = boolInR8.getValue(1);
SDOperand zeroReg = DAG.getCopyFromReg(Chain, IA64::r0, MVT::i64, InFlag);
InFlag = zeroReg.getValue(2);
Chain = zeroReg.getValue(1);
RetVal = DAG.getSetCC(MVT::i1, boolInR8, zeroReg, ISD::SETNE);
break;
}
case MVT::i8:
case MVT::i16:
case MVT::i32:
RetVal = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
Chain = RetVal.getValue(1);
// keep track of whether it is sign or zero extended (todo: bools?)
/* XXX
RetVal = DAG.getNode(RetTy->isSigned() ? ISD::AssertSext :ISD::AssertZext,
MVT::i64, RetVal, DAG.getValueType(RetTyVT));
*/
RetVal = DAG.getNode(ISD::TRUNCATE, RetTyVT, RetVal);
break;
case MVT::i64:
RetVal = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
Chain = RetVal.getValue(1);
InFlag = RetVal.getValue(2); // XXX dead
break;
case MVT::f32:
RetVal = DAG.getCopyFromReg(Chain, IA64::F8, MVT::f64, InFlag);
Chain = RetVal.getValue(1);
RetVal = DAG.getNode(ISD::TRUNCATE, MVT::f32, RetVal);
break;
case MVT::f64:
RetVal = DAG.getCopyFromReg(Chain, IA64::F8, MVT::f64, InFlag);
Chain = RetVal.getValue(1);
InFlag = RetVal.getValue(2); // XXX dead
break;
}
}
Chain = DAG.getCALLSEQ_END(Chain,
DAG.getConstant(NumBytes, getPointerTy()),
DAG.getConstant(0, getPointerTy()),
SDOperand());
return std::make_pair(RetVal, Chain);
}
SDOperand IA64TargetLowering::
LowerOperation(SDOperand Op, SelectionDAG &DAG) {
switch (Op.getOpcode()) {
default: assert(0 && "Should not custom lower this!");
case ISD::GlobalTLSAddress:
assert(0 && "TLS not implemented for IA64.");
case ISD::RET: {
SDOperand AR_PFSVal, Copy;
switch(Op.getNumOperands()) {
default:
assert(0 && "Do not know how to return this many arguments!");
abort();
case 1:
AR_PFSVal = DAG.getCopyFromReg(Op.getOperand(0), VirtGPR, MVT::i64);
AR_PFSVal = DAG.getCopyToReg(AR_PFSVal.getValue(1), IA64::AR_PFS,
AR_PFSVal);
return DAG.getNode(IA64ISD::RET_FLAG, MVT::Other, AR_PFSVal);
case 3: {
// Copy the result into the output register & restore ar.pfs
MVT::ValueType ArgVT = Op.getOperand(1).getValueType();
unsigned ArgReg = MVT::isInteger(ArgVT) ? IA64::r8 : IA64::F8;
AR_PFSVal = DAG.getCopyFromReg(Op.getOperand(0), VirtGPR, MVT::i64);
Copy = DAG.getCopyToReg(AR_PFSVal.getValue(1), ArgReg, Op.getOperand(1),
SDOperand());
AR_PFSVal = DAG.getCopyToReg(Copy.getValue(0), IA64::AR_PFS, AR_PFSVal,
Copy.getValue(1));
return DAG.getNode(IA64ISD::RET_FLAG, MVT::Other,
AR_PFSVal, AR_PFSVal.getValue(1));
}
}
return SDOperand();
}
case ISD::VAARG: {
MVT::ValueType VT = getPointerTy();
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
SDOperand VAList = DAG.getLoad(VT, Op.getOperand(0), Op.getOperand(1),
SV, 0);
// Increment the pointer, VAList, to the next vaarg
SDOperand VAIncr = DAG.getNode(ISD::ADD, VT, VAList,
DAG.getConstant(MVT::getSizeInBits(VT)/8,
VT));
// Store the incremented VAList to the legalized pointer
VAIncr = DAG.getStore(VAList.getValue(1), VAIncr,
Op.getOperand(1), SV, 0);
// Load the actual argument out of the pointer VAList
return DAG.getLoad(Op.getValueType(), VAIncr, VAList, NULL, 0);
}
case ISD::VASTART: {
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i64);
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
return DAG.getStore(Op.getOperand(0), FR, Op.getOperand(1), SV, 0);
}
// Frame & Return address. Currently unimplemented
case ISD::RETURNADDR: break;
case ISD::FRAMEADDR: break;
}
return SDOperand();
}
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