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//===-- SystemZISelLowering.cpp - SystemZ 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 SystemZTargetLowering class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "systemz-lower"
#include "SystemZISelLowering.h"
#include "SystemZ.h"
#include "SystemZTargetMachine.h"
#include "SystemZSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Intrinsics.h"
#include "llvm/CallingConv.h"
#include "llvm/GlobalVariable.h"
#include "llvm/GlobalAlias.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/VectorExtras.h"
using namespace llvm;
SystemZTargetLowering::SystemZTargetLowering(SystemZTargetMachine &tm) :
TargetLowering(tm), Subtarget(*tm.getSubtargetImpl()), TM(tm) {
// Set up the register classes.
addRegisterClass(MVT::i32, SystemZ::GR32RegisterClass);
addRegisterClass(MVT::i64, SystemZ::GR64RegisterClass);
// Compute derived properties from the register classes
computeRegisterProperties();
// Set shifts properties
setShiftAmountFlavor(Extend);
setShiftAmountType(MVT::i32);
// Provide all sorts of operation actions
setStackPointerRegisterToSaveRestore(SystemZ::R15D);
setSchedulingPreference(SchedulingForLatency);
setOperationAction(ISD::RET, MVT::Other, Custom);
}
SDValue SystemZTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
switch (Op.getOpcode()) {
case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG);
case ISD::RET: return LowerRET(Op, DAG);
default:
assert(0 && "unimplemented operand");
return SDValue();
}
}
//===----------------------------------------------------------------------===//
// Calling Convention Implementation
//===----------------------------------------------------------------------===//
#include "SystemZGenCallingConv.inc"
SDValue SystemZTargetLowering::LowerFORMAL_ARGUMENTS(SDValue Op,
SelectionDAG &DAG) {
unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
switch (CC) {
default:
assert(0 && "Unsupported calling convention");
case CallingConv::C:
case CallingConv::Fast:
return LowerCCCArguments(Op, DAG);
}
}
/// LowerCCCArguments - transform physical registers into virtual registers and
/// generate load operations for arguments places on the stack.
// FIXME: struct return stuff
// FIXME: varargs
SDValue SystemZTargetLowering::LowerCCCArguments(SDValue Op,
SelectionDAG &DAG) {
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
SDValue Root = Op.getOperand(0);
bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
unsigned CC = MF.getFunction()->getCallingConv();
DebugLoc dl = Op.getDebugLoc();
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_SystemZ);
assert(!isVarArg && "Varargs not supported yet");
SmallVector<SDValue, 16> ArgValues;
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
if (VA.isRegLoc()) {
// Arguments passed in registers
MVT RegVT = VA.getLocVT();
switch (RegVT.getSimpleVT()) {
default:
cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
<< RegVT.getSimpleVT()
<< "\n";
abort();
case MVT::i64:
unsigned VReg =
RegInfo.createVirtualRegister(SystemZ::GR64RegisterClass);
RegInfo.addLiveIn(VA.getLocReg(), VReg);
SDValue ArgValue = DAG.getCopyFromReg(Root, dl, VReg, RegVT);
// If this is an 8/16/32-bit value, it is really passed promoted to 64
// bits. Insert an assert[sz]ext to capture this, then truncate to the
// right size.
if (VA.getLocInfo() == CCValAssign::SExt)
ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
else if (VA.getLocInfo() == CCValAssign::ZExt)
ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
if (VA.getLocInfo() != CCValAssign::Full)
ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
ArgValues.push_back(ArgValue);
}
} else {
// Sanity check
assert(VA.isMemLoc());
// Load the argument to a virtual register
unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
if (ObjSize > 8) {
cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
<< VA.getLocVT().getSimpleVT()
<< "\n";
}
// Create the frame index object for this incoming parameter...
int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset());
// Create the SelectionDAG nodes corresponding to a load
//from this parameter
SDValue FIN = DAG.getFrameIndex(FI, MVT::i64);
ArgValues.push_back(DAG.getLoad(VA.getLocVT(), dl, Root, FIN,
PseudoSourceValue::getFixedStack(FI), 0));
}
}
ArgValues.push_back(Root);
// Return the new list of results.
return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getNode()->getVTList(),
&ArgValues[0], ArgValues.size()).getValue(Op.getResNo());
}
SDValue SystemZTargetLowering::LowerRET(SDValue Op, SelectionDAG &DAG) {
// CCValAssign - represent the assignment of the return value to a location
SmallVector<CCValAssign, 16> RVLocs;
unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
DebugLoc dl = Op.getDebugLoc();
// CCState - Info about the registers and stack slot.
CCState CCInfo(CC, isVarArg, getTargetMachine(), RVLocs);
// Analize return values of ISD::RET
CCInfo.AnalyzeReturn(Op.getNode(), RetCC_SystemZ);
// If this is the first return lowered for this function, add the regs to the
// liveout set for the function.
if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
for (unsigned i = 0; i != RVLocs.size(); ++i)
if (RVLocs[i].isRegLoc())
DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
}
// The chain is always operand #0
SDValue Chain = Op.getOperand(0);
SDValue Flag;
// Copy the result values into the output registers.
for (unsigned i = 0; i != RVLocs.size(); ++i) {
CCValAssign &VA = RVLocs[i];
SDValue ResValue = Op.getOperand(i*2+1);
assert(VA.isRegLoc() && "Can only return in registers!");
// If this is an 8/16/32-bit value, it is really should be passed promoted
// to 64 bits.
if (VA.getLocInfo() == CCValAssign::SExt)
ResValue = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), ResValue);
else if (VA.getLocInfo() == CCValAssign::ZExt)
ResValue = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), ResValue);
else if (VA.getLocInfo() == CCValAssign::AExt)
ResValue = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), ResValue);
// ISD::RET => ret chain, (regnum1,val1), ...
// So i*2+1 index only the regnums
Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), ResValue, Flag);
// Guarantee that all emitted copies are stuck together,
// avoiding something bad.
Flag = Chain.getValue(1);
}
if (Flag.getNode())
return DAG.getNode(SystemZISD::RET_FLAG, dl, MVT::Other, Chain, Flag);
// Return Void
return DAG.getNode(SystemZISD::RET_FLAG, dl, MVT::Other, Chain);
}
const char *SystemZTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
case SystemZISD::RET_FLAG: return "SystemZISD::RET_FLAG";
default: return NULL;
}
}
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