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llvm-6502/lib/Target/IA64/IA64ISelLowering.cpp
Duraid Madina 64aa0ea4e9 this is a hack, which may or may not hang around. In short: 
whimper out of doing things the Right Way, and hack up a generic
'BRCALL' instruction, that gets generated when calls are lowered.
This gets selected by hand in the DAG isel, where it gets turned
into real (i.e. in tablegen) br.call instructions.

BUG: this dies on void calls, but seems to work otherwise?


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24952 91177308-0d34-0410-b5e6-96231b3b80d8
2005-12-22 13:29:14 +00:00

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//===-- IA64ISelLowering.cpp - IA64 DAG Lowering Implementation -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Duraid Madina and 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/SSARegMap.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);
setOperationAction(ISD::BRCONDTWOWAY , MVT::Other, Expand);
setOperationAction(ISD::BRTWOWAY_CC , MVT::Other, Expand);
setOperationAction(ISD::FP_ROUND_INREG , MVT::f32 , Expand);
setSetCCResultType(MVT::i1);
setShiftAmountType(MVT::i64);
setOperationAction(ISD::EXTLOAD , MVT::i1 , Promote);
setOperationAction(ISD::ZEXTLOAD , MVT::i1 , Expand);
setOperationAction(ISD::SEXTLOAD , MVT::i1 , Expand);
setOperationAction(ISD::SEXTLOAD , MVT::i8 , Expand);
setOperationAction(ISD::SEXTLOAD , MVT::i16 , Expand);
setOperationAction(ISD::SEXTLOAD , MVT::i32 , Expand);
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::SINT_TO_FP , MVT::i1 , Promote);
setOperationAction(ISD::UINT_TO_FP , MVT::i1 , Promote);
// We don't support sin/cos/sqrt
setOperationAction(ISD::FSIN , MVT::f64, Expand);
setOperationAction(ISD::FCOS , MVT::f64, Expand);
setOperationAction(ISD::FSQRT, MVT::f64, Expand);
setOperationAction(ISD::FSIN , MVT::f32, Expand);
setOperationAction(ISD::FCOS , MVT::f32, Expand);
setOperationAction(ISD::FSQRT, MVT::f32, Expand);
// We don't have line number support yet.
setOperationAction(ISD::LOCATION, MVT::Other, Expand);
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
//IA64 has these, but they are not implemented
setOperationAction(ISD::CTTZ , MVT::i64 , Expand);
setOperationAction(ISD::CTLZ , MVT::i64 , Expand);
computeRegisterProperties();
addLegalFPImmediate(+0.0);
addLegalFPImmediate(+1.0);
}
/// 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;
}
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();
GP = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
SP = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
RP = MF.getSSARegMap()->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.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.getSSARegMap()->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);
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.addLiveIn(args_int[count]); // mark this register as liveIn
argVreg[count] =
MF.getSSARegMap()->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, DAG.getSrcValue(NULL));
}
++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.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
BuildMI(&BB, IA64::PSEUDO_ALLOC, 0, 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, argOpc[i], 1, 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, IA64::MOV, 1, IA64::r22).addFrameIndex(FI);
// FIXME: we should use st8.spill here, one day
BuildMI(&BB, IA64::ST8, 1, 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.addLiveOut(IA64::r8);
break;
case MVT::f32:
case MVT::f64:
MF.addLiveOut(IA64::F8);
break;
}
return ArgValues;
}
std::pair<SDOperand, SDOperand>
IA64TargetLowering::LowerCallTo(SDOperand Chain,
const Type *RetTy, 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.getNode(ISD::CALLSEQ_START, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
SDOperand StackPtr, NullSV;
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].first;
MVT::ValueType ObjectVT = Val.getValueType();
SDOperand ValToStore, ValToConvert;
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
if(Args[i].second->isSigned())
Val = DAG.getNode(ISD::SIGN_EXTEND, MVT::i64, Val);
else
Val = DAG.getNode(ISD::ZERO_EXTEND, 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);
NullSV = DAG.getSrcValue(NULL);
}
SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i64, StackPtr, PtrOff);
Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
ValToStore, PtrOff, NullSV));
}
if(ValToConvert.Val) {
Converts.push_back(DAG.getNode(IA64ISD::GETFD, MVT::i64, ValToConvert));
}
ArgOffset += ObjSize;
}
// Emit all stores, make sure they occur before any copies into physregs.
if (!Stores.empty())
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, Stores);
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;
InFlag = Chain.getValue(1);
SDOperand SPBeforeCall = DAG.getCopyFromReg(Chain, IA64::r12, MVT::i64, InFlag);
Chain = SPBeforeCall;
InFlag = Chain.getValue(1);
SDOperand RPBeforeCall = DAG.getCopyFromReg(Chain, IA64::rp, MVT::i64, InFlag);
Chain = RPBeforeCall;
InFlag = Chain.getValue(1);
// 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
// free-floating
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++]);
}
}
// next copy args into the usual places
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);
/* out with the old...
Chain = SDOperand(DAG.getCall(NodeTys, Chain, Callee, InFlag), 0);
else
Chain = SDOperand(DAG.getCall(NodeTys, Chain, Callee), 0);
*/
// to make way for a hack:
Chain = DAG.getNode(IA64ISD::BRCALL, NodeTys, CallOperands);
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)
SDOperand boolInR8 = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
RetVal = DAG.getTargetNode(IA64::CMPNE, MVT::i1, // FIXME: is this flagged correctly?
DAG.getRegister(IA64::r0, MVT::i64), boolInR8, Chain, InFlag);
Chain = RetVal.getValue(1);
// Add a note to keep track of whether it is sign or zero extended - TODO: bools
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::i8:
case MVT::i16:
case MVT::i32:
RetVal = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
Chain = RetVal.getValue(1);
// Add a note to keep track of whether it is sign or zero extended - TODO: bools
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);
break;
case MVT::f64:
RetVal = DAG.getCopyFromReg(Chain, IA64::F8, MVT::f64, InFlag);
Chain = RetVal.getValue(1);
break;
}
}
Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
return std::make_pair(RetVal, Chain);
}
SDOperand
IA64TargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP,
Value *VAListV, SelectionDAG &DAG) {
// vastart just stores the address of the VarArgsFrameIndex slot.
SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i64);
return DAG.getNode(ISD::STORE, MVT::Other, Chain, FR,
VAListP, DAG.getSrcValue(VAListV));
}
std::pair<SDOperand,SDOperand> IA64TargetLowering::
LowerVAArg(SDOperand Chain, SDOperand VAListP, Value *VAListV,
const Type *ArgTy, SelectionDAG &DAG) {
MVT::ValueType ArgVT = getValueType(ArgTy);
SDOperand Val = DAG.getLoad(MVT::i64, Chain,
VAListP, DAG.getSrcValue(VAListV));
SDOperand Result = DAG.getLoad(ArgVT, DAG.getEntryNode(), Val,
DAG.getSrcValue(NULL));
unsigned Amt;
if (ArgVT == MVT::i32 || ArgVT == MVT::f32)
Amt = 8;
else {
assert((ArgVT == MVT::i64 || ArgVT == MVT::f64) &&
"Other types should have been promoted for varargs!");
Amt = 8;
}
Val = DAG.getNode(ISD::ADD, Val.getValueType(), Val,
DAG.getConstant(Amt, Val.getValueType()));
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain,
Val, VAListP, DAG.getSrcValue(VAListV));
return std::make_pair(Result, Chain);
}
std::pair<SDOperand, SDOperand> IA64TargetLowering::
LowerFrameReturnAddress(bool isFrameAddress, SDOperand Chain, unsigned Depth,
SelectionDAG &DAG) {
assert(0 && "LowerFrameReturnAddress unimplemented");
abort();
}
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