llvm-6502/lib/Target/Mips/MipsISelDAGToDAG.cpp
2011-10-11 00:44:20 +00:00

350 lines
12 KiB
C++

//===-- MipsISelDAGToDAG.cpp - A dag to dag inst selector for Mips --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines an instruction selector for the MIPS target.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-isel"
#include "Mips.h"
#include "MipsMachineFunction.h"
#include "MipsRegisterInfo.h"
#include "MipsSubtarget.h"
#include "MipsTargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CFG.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// MipsDAGToDAGISel - MIPS specific code to select MIPS machine
// instructions for SelectionDAG operations.
//===----------------------------------------------------------------------===//
namespace {
class MipsDAGToDAGISel : public SelectionDAGISel {
/// TM - Keep a reference to MipsTargetMachine.
MipsTargetMachine &TM;
/// Subtarget - Keep a pointer to the MipsSubtarget around so that we can
/// make the right decision when generating code for different targets.
const MipsSubtarget &Subtarget;
public:
explicit MipsDAGToDAGISel(MipsTargetMachine &tm) :
SelectionDAGISel(tm),
TM(tm), Subtarget(tm.getSubtarget<MipsSubtarget>()) {}
// Pass Name
virtual const char *getPassName() const {
return "MIPS DAG->DAG Pattern Instruction Selection";
}
private:
// Include the pieces autogenerated from the target description.
#include "MipsGenDAGISel.inc"
/// getTargetMachine - Return a reference to the TargetMachine, casted
/// to the target-specific type.
const MipsTargetMachine &getTargetMachine() {
return static_cast<const MipsTargetMachine &>(TM);
}
/// getInstrInfo - Return a reference to the TargetInstrInfo, casted
/// to the target-specific type.
const MipsInstrInfo *getInstrInfo() {
return getTargetMachine().getInstrInfo();
}
SDNode *getGlobalBaseReg();
SDNode *Select(SDNode *N);
// Complex Pattern.
bool SelectAddr(SDValue N, SDValue &Base, SDValue &Offset);
// getI32Imm - Return a target constant with the specified
// value, of type i32.
inline SDValue getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
char ConstraintCode,
std::vector<SDValue> &OutOps);
};
}
/// getGlobalBaseReg - Output the instructions required to put the
/// GOT address into a register.
SDNode *MipsDAGToDAGISel::getGlobalBaseReg() {
unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
}
/// ComplexPattern used on MipsInstrInfo
/// Used on Mips Load/Store instructions
bool MipsDAGToDAGISel::
SelectAddr(SDValue Addr, SDValue &Base, SDValue &Offset) {
EVT ValTy = Addr.getValueType();
unsigned GPReg = ValTy == MVT::i32 ? Mips::GP : Mips::GP_64;
// if Address is FI, get the TargetFrameIndex.
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
Offset = CurDAG->getTargetConstant(0, ValTy);
return true;
}
// on PIC code Load GA
if (TM.getRelocationModel() == Reloc::PIC_) {
if (Addr.getOpcode() == MipsISD::WrapperPIC) {
Base = CurDAG->getRegister(GPReg, ValTy);
Offset = Addr.getOperand(0);
return true;
}
} else {
if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
Addr.getOpcode() == ISD::TargetGlobalAddress))
return false;
else if (Addr.getOpcode() == ISD::TargetGlobalTLSAddress) {
Base = CurDAG->getRegister(GPReg, ValTy);
Offset = Addr;
return true;
}
}
// Addresses of the form FI+const or FI|const
if (CurDAG->isBaseWithConstantOffset(Addr)) {
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
if (isInt<16>(CN->getSExtValue())) {
// If the first operand is a FI, get the TargetFI Node
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
(Addr.getOperand(0)))
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
else
Base = Addr.getOperand(0);
Offset = CurDAG->getTargetConstant(CN->getZExtValue(), ValTy);
return true;
}
}
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
// When loading from constant pools, load the lower address part in
// the instruction itself. Example, instead of:
// lui $2, %hi($CPI1_0)
// addiu $2, $2, %lo($CPI1_0)
// lwc1 $f0, 0($2)
// Generate:
// lui $2, %hi($CPI1_0)
// lwc1 $f0, %lo($CPI1_0)($2)
if ((Addr.getOperand(0).getOpcode() == MipsISD::Hi ||
Addr.getOperand(0).getOpcode() == ISD::LOAD) &&
Addr.getOperand(1).getOpcode() == MipsISD::Lo) {
SDValue LoVal = Addr.getOperand(1);
if (isa<ConstantPoolSDNode>(LoVal.getOperand(0)) ||
isa<GlobalAddressSDNode>(LoVal.getOperand(0))) {
Base = Addr.getOperand(0);
Offset = LoVal.getOperand(0);
return true;
}
}
}
Base = Addr;
Offset = CurDAG->getTargetConstant(0, ValTy);
return true;
}
/// Select instructions not customized! Used for
/// expanded, promoted and normal instructions
SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
unsigned Opcode = Node->getOpcode();
DebugLoc dl = Node->getDebugLoc();
// Dump information about the Node being selected
DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
return NULL;
}
///
// Instruction Selection not handled by the auto-generated
// tablegen selection should be handled here.
///
switch(Opcode) {
default: break;
case ISD::SUBE:
case ISD::ADDE: {
SDValue InFlag = Node->getOperand(2), CmpLHS;
unsigned Opc = InFlag.getOpcode(); (void)Opc;
assert(((Opc == ISD::ADDC || Opc == ISD::ADDE) ||
(Opc == ISD::SUBC || Opc == ISD::SUBE)) &&
"(ADD|SUB)E flag operand must come from (ADD|SUB)C/E insn");
unsigned MOp;
if (Opcode == ISD::ADDE) {
CmpLHS = InFlag.getValue(0);
MOp = Mips::ADDu;
} else {
CmpLHS = InFlag.getOperand(0);
MOp = Mips::SUBu;
}
SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, dl, VT, Ops, 2);
SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, dl, VT,
SDValue(Carry,0), RHS);
return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue,
LHS, SDValue(AddCarry,0));
}
/// Mul with two results
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
assert(Node->getValueType(0) != MVT::i64 &&
"64-bit multiplication with two results not handled.");
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
unsigned Op;
Op = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);
SDNode *Mul = CurDAG->getMachineNode(Op, dl, MVT::Glue, Op1, Op2);
SDValue InFlag = SDValue(Mul, 0);
SDNode *Lo = CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32,
MVT::Glue, InFlag);
InFlag = SDValue(Lo,1);
SDNode *Hi = CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 0), SDValue(Lo,0));
if (!SDValue(Node, 1).use_empty())
ReplaceUses(SDValue(Node, 1), SDValue(Hi,0));
return NULL;
}
/// Special Muls
case ISD::MUL:
// Mips32 has a 32-bit three operand mul instruction.
if (Subtarget.hasMips32() && Node->getValueType(0) == MVT::i32)
break;
case ISD::MULHS:
case ISD::MULHU: {
assert((Opcode == ISD::MUL || Node->getValueType(0) != MVT::i64) &&
"64-bit MULH* not handled.");
EVT Ty = Node->getValueType(0);
SDValue MulOp1 = Node->getOperand(0);
SDValue MulOp2 = Node->getOperand(1);
unsigned MulOp = (Opcode == ISD::MULHU ?
Mips::MULTu :
(Ty == MVT::i32 ? Mips::MULT : Mips::DMULT));
SDNode *MulNode = CurDAG->getMachineNode(MulOp, dl,
MVT::Glue, MulOp1, MulOp2);
SDValue InFlag = SDValue(MulNode, 0);
if (Opcode == ISD::MUL) {
unsigned Opc = (Ty == MVT::i32 ? Mips::MFLO : Mips::MFLO64);
return CurDAG->getMachineNode(Opc, dl, Ty, InFlag);
}
else
return CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
}
// Get target GOT address.
case ISD::GLOBAL_OFFSET_TABLE:
return getGlobalBaseReg();
case ISD::ConstantFP: {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO, MVT::i32);
return CurDAG->getMachineNode(Mips::BuildPairF64, dl, MVT::f64, Zero,
Zero);
}
break;
}
case MipsISD::ThreadPointer: {
unsigned SrcReg = Mips::HWR29;
unsigned DestReg = Mips::V1;
SDNode *Rdhwr = CurDAG->getMachineNode(Mips::RDHWR, Node->getDebugLoc(),
Node->getValueType(0), CurDAG->getRegister(SrcReg, MVT::i32));
SDValue Chain = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, DestReg,
SDValue(Rdhwr, 0));
SDValue ResNode = CurDAG->getCopyFromReg(Chain, dl, DestReg, MVT::i32);
ReplaceUses(SDValue(Node, 0), ResNode);
return ResNode.getNode();
}
}
// Select the default instruction
SDNode *ResNode = SelectCode(Node);
DEBUG(errs() << "=> ");
if (ResNode == NULL || ResNode == Node)
DEBUG(Node->dump(CurDAG));
else
DEBUG(ResNode->dump(CurDAG));
DEBUG(errs() << "\n");
return ResNode;
}
bool MipsDAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
OutOps.push_back(Op);
return false;
}
/// createMipsISelDag - This pass converts a legalized DAG into a
/// MIPS-specific DAG, ready for instruction scheduling.
FunctionPass *llvm::createMipsISelDag(MipsTargetMachine &TM) {
return new MipsDAGToDAGISel(TM);
}