llvm-6502/lib/Target/Mips/MipsISelDAGToDAG.cpp
Chris Lattner 30baa95afd silence warning when asserts disabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61014 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-14 21:38:24 +00:00

390 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 "MipsISelLowering.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/Compiler.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// MipsDAGToDAGISel - MIPS specific code to select MIPS machine
// instructions for SelectionDAG operations.
//===----------------------------------------------------------------------===//
namespace {
class VISIBILITY_HIDDEN 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.getTargetLowering()),
TM(tm), Subtarget(tm.getSubtarget<MipsSubtarget>()) {}
virtual void InstructionSelect();
// 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"
SDValue getGlobalBaseReg();
SDNode *Select(SDValue N);
// Complex Pattern.
bool SelectAddr(SDValue Op, 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);
}
#ifndef NDEBUG
unsigned Indent;
#endif
};
}
/// InstructionSelect - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
void MipsDAGToDAGISel::
InstructionSelect()
{
DEBUG(BB->dump());
// Codegen the basic block.
#ifndef NDEBUG
DOUT << "===== Instruction selection begins:\n";
Indent = 0;
#endif
// Select target instructions for the DAG.
SelectRoot(*CurDAG);
#ifndef NDEBUG
DOUT << "===== Instruction selection ends:\n";
#endif
CurDAG->RemoveDeadNodes();
}
/// getGlobalBaseReg - Output the instructions required to put the
/// GOT address into a register.
SDValue MipsDAGToDAGISel::getGlobalBaseReg() {
MachineFunction* MF = BB->getParent();
unsigned GP = 0;
for(MachineRegisterInfo::livein_iterator ii = MF->getRegInfo().livein_begin(),
ee = MF->getRegInfo().livein_end(); ii != ee; ++ii)
if (ii->first == Mips::GP) {
GP = ii->second;
break;
}
assert(GP && "GOT PTR not in liveins");
return CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
GP, MVT::i32);
}
/// ComplexPattern used on MipsInstrInfo
/// Used on Mips Load/Store instructions
bool MipsDAGToDAGISel::
SelectAddr(SDValue Op, SDValue Addr, SDValue &Offset, SDValue &Base)
{
// if Address is FI, get the TargetFrameIndex.
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
Offset = CurDAG->getTargetConstant(0, MVT::i32);
return true;
}
// on PIC code Load GA
if (TM.getRelocationModel() == Reloc::PIC_) {
if ((Addr.getOpcode() == ISD::TargetGlobalAddress) ||
(Addr.getOpcode() == ISD::TargetJumpTable)){
Base = CurDAG->getRegister(Mips::GP, MVT::i32);
Offset = Addr;
return true;
}
} else {
if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
Addr.getOpcode() == ISD::TargetGlobalAddress))
return false;
}
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
if (Predicate_immSExt16(CN)) {
// 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(), MVT::i32);
} else {
Base = Addr.getOperand(0);
}
Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
return true;
}
}
}
Base = Addr;
Offset = CurDAG->getTargetConstant(0, MVT::i32);
return true;
}
/// Select instructions not customized! Used for
/// expanded, promoted and normal instructions
SDNode* MipsDAGToDAGISel::
Select(SDValue N)
{
SDNode *Node = N.getNode();
unsigned Opcode = Node->getOpcode();
// Dump information about the Node being selected
#ifndef NDEBUG
DOUT << std::string(Indent, ' ') << "Selecting: ";
DEBUG(Node->dump(CurDAG));
DOUT << "\n";
Indent += 2;
#endif
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "== ";
DEBUG(Node->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
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(); Opc=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);
MVT VT = LHS.getValueType();
SDNode *Carry = CurDAG->getTargetNode(Mips::SLTu, VT, Ops, 2);
SDNode *AddCarry = CurDAG->getTargetNode(Mips::ADDu, VT,
SDValue(Carry,0), RHS);
return CurDAG->SelectNodeTo(N.getNode(), MOp, VT, MVT::Flag,
LHS, SDValue(AddCarry,0));
}
/// Mul/Div with two results
case ISD::SDIVREM:
case ISD::UDIVREM:
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
unsigned Op;
if (Opcode == ISD::UMUL_LOHI || Opcode == ISD::SMUL_LOHI)
Op = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);
else
Op = (Opcode == ISD::UDIVREM ? Mips::DIVu : Mips::DIV);
SDNode *Node = CurDAG->getTargetNode(Op, MVT::Flag, Op1, Op2);
SDValue InFlag = SDValue(Node, 0);
SDNode *Lo = CurDAG->getTargetNode(Mips::MFLO, MVT::i32,
MVT::Flag, InFlag);
InFlag = SDValue(Lo,1);
SDNode *Hi = CurDAG->getTargetNode(Mips::MFHI, MVT::i32, InFlag);
if (!N.getValue(0).use_empty())
ReplaceUses(N.getValue(0), SDValue(Lo,0));
if (!N.getValue(1).use_empty())
ReplaceUses(N.getValue(1), SDValue(Hi,0));
return NULL;
}
/// Special Muls
case ISD::MUL:
case ISD::MULHS:
case ISD::MULHU: {
SDValue MulOp1 = Node->getOperand(0);
SDValue MulOp2 = Node->getOperand(1);
unsigned MulOp = (Opcode == ISD::MULHU ? Mips::MULTu : Mips::MULT);
SDNode *MulNode = CurDAG->getTargetNode(MulOp, MVT::Flag, MulOp1, MulOp2);
SDValue InFlag = SDValue(MulNode, 0);
if (MulOp == ISD::MUL)
return CurDAG->getTargetNode(Mips::MFLO, MVT::i32, InFlag);
else
return CurDAG->getTargetNode(Mips::MFHI, MVT::i32, InFlag);
}
/// Div/Rem operations
case ISD::SREM:
case ISD::UREM:
case ISD::SDIV:
case ISD::UDIV: {
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
unsigned Op, MOp;
if (Opcode == ISD::SDIV || Opcode == ISD::UDIV) {
Op = (Opcode == ISD::SDIV ? Mips::DIV : Mips::DIVu);
MOp = Mips::MFLO;
} else {
Op = (Opcode == ISD::SREM ? Mips::DIV : Mips::DIVu);
MOp = Mips::MFHI;
}
SDNode *Node = CurDAG->getTargetNode(Op, MVT::Flag, Op1, Op2);
SDValue InFlag = SDValue(Node, 0);
return CurDAG->getTargetNode(MOp, MVT::i32, InFlag);
}
// Get target GOT address.
case ISD::GLOBAL_OFFSET_TABLE: {
SDValue Result = getGlobalBaseReg();
ReplaceUses(N, Result);
return NULL;
}
/// Handle direct and indirect calls when using PIC. On PIC, when
/// GOT is smaller than about 64k (small code) the GA target is
/// loaded with only one instruction. Otherwise GA's target must
/// be loaded with 3 instructions.
case MipsISD::JmpLink: {
if (TM.getRelocationModel() == Reloc::PIC_) {
//bool isCodeLarge = (TM.getCodeModel() == CodeModel::Large);
SDValue Chain = Node->getOperand(0);
SDValue Callee = Node->getOperand(1);
SDValue T9Reg = CurDAG->getRegister(Mips::T9, MVT::i32);
SDValue InFlag(0, 0);
if ( (isa<GlobalAddressSDNode>(Callee)) ||
(isa<ExternalSymbolSDNode>(Callee)) )
{
/// Direct call for global addresses and external symbols
SDValue GPReg = CurDAG->getRegister(Mips::GP, MVT::i32);
// Use load to get GOT target
SDValue Ops[] = { Callee, GPReg, Chain };
SDValue Load = SDValue(CurDAG->getTargetNode(Mips::LW, MVT::i32,
MVT::Other, Ops, 3), 0);
Chain = Load.getValue(1);
// Call target must be on T9
Chain = CurDAG->getCopyToReg(Chain, T9Reg, Load, InFlag);
} else
/// Indirect call
Chain = CurDAG->getCopyToReg(Chain, T9Reg, Callee, InFlag);
// Emit Jump and Link Register
SDNode *ResNode = CurDAG->getTargetNode(Mips::JALR, MVT::Other,
MVT::Flag, T9Reg, Chain);
Chain = SDValue(ResNode, 0);
InFlag = SDValue(ResNode, 1);
ReplaceUses(SDValue(Node, 0), Chain);
ReplaceUses(SDValue(Node, 1), InFlag);
return ResNode;
}
}
}
// Select the default instruction
SDNode *ResNode = SelectCode(N);
#ifndef NDEBUG
DOUT << std::string(Indent-2, ' ') << "=> ";
if (ResNode == NULL || ResNode == N.getNode())
DEBUG(N.getNode()->dump(CurDAG));
else
DEBUG(ResNode->dump(CurDAG));
DOUT << "\n";
Indent -= 2;
#endif
return ResNode;
}
/// 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);
}