mirror of
https://github.com/c64scene-ar/llvm-6502.git
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164 lines
5.3 KiB
C++
164 lines
5.3 KiB
C++
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//===-- X86ISelPattern.cpp - A DAG pattern matching inst selector for X86 -===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the Evan Cheng and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a DAG pattern matching instruction selector for X86,
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// converting from a legalized dag to a X86 dag.
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//
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//===----------------------------------------------------------------------===//
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#include "X86.h"
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#include "X86Subtarget.h"
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#include "X86ISelLowering.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/SelectionDAGISel.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/ADT/Statistic.h"
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// Pattern Matcher Implementation
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//===----------------------------------------------------------------------===//
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namespace {
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Statistic<>
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NumFPKill("x86-codegen", "Number of FP_REG_KILL instructions added");
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//===--------------------------------------------------------------------===//
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/// ISel - X86 specific code to select X86 machine instructions for
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/// SelectionDAG operations.
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///
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class X86DAGToDAGISel : public SelectionDAGISel {
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/// ContainsFPCode - Every instruction we select that uses or defines a FP
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/// register should set this to true.
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bool ContainsFPCode;
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/// X86Lowering - This object fully describes how to lower LLVM code to an
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/// X86-specific SelectionDAG.
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X86TargetLowering X86Lowering;
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/// Subtarget - Keep a pointer to the X86Subtarget around so that we can
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/// make the right decision when generating code for different targets.
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const X86Subtarget *Subtarget;
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public:
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X86DAGToDAGISel(TargetMachine &TM)
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: SelectionDAGISel(X86Lowering), X86Lowering(TM) {
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Subtarget = &TM.getSubtarget<X86Subtarget>();
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}
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virtual const char *getPassName() const {
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return "X86 DAG->DAG Instruction Selection";
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}
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/// InstructionSelectBasicBlock - This callback is invoked by
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/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
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virtual void InstructionSelectBasicBlock(SelectionDAG &DAG);
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// Include the pieces autogenerated from the target description.
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#include "X86GenDAGISel.inc"
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private:
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SDOperand Select(SDOperand N);
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/// getI16Imm - Return a target constant with the specified value, of type
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/// i16.
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inline SDOperand getI16Imm(unsigned Imm) {
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return CurDAG->getTargetConstant(Imm, MVT::i16);
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}
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/// getI32Imm - Return a target constant with the specified value, of type
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/// i32.
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inline SDOperand getI32Imm(unsigned Imm) {
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return CurDAG->getTargetConstant(Imm, MVT::i32);
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}
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};
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}
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/// InstructionSelectBasicBlock - This callback is invoked by SelectionDAGISel
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/// when it has created a SelectionDAG for us to codegen.
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void X86DAGToDAGISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
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DEBUG(BB->dump());
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// Codegen the basic block.
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DAG.setRoot(Select(DAG.getRoot()));
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DAG.RemoveDeadNodes();
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// Emit machine code to BB.
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ScheduleAndEmitDAG(DAG);
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}
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SDOperand X86DAGToDAGISel::Select(SDOperand Op) {
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SDNode *N = Op.Val;
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MVT::ValueType OpVT = Op.getValueType();
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unsigned Opc;
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if (N->getOpcode() >= ISD::BUILTIN_OP_END)
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return Op; // Already selected.
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switch (N->getOpcode()) {
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default: break;
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case ISD::Constant: {
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switch (OpVT) {
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default: assert(0 && "Cannot use constants of this type!");
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case MVT::i1:
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case MVT::i8: Opc = X86::MOV8ri; break;
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case MVT::i16: Opc = X86::MOV16ri; break;
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case MVT::i32: Opc = X86::MOV32ri; break;
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}
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unsigned CVal = cast<ConstantSDNode>(N)->getValue();
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SDOperand Op1 = CurDAG->getTargetConstant(CVal, OpVT);
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CurDAG->SelectNodeTo(N, Opc, OpVT, Op1);
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return Op;
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}
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case ISD::RET: {
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SDOperand Chain = Select(N->getOperand(0)); // Token chain.
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switch (N->getNumOperands()) {
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default:
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assert(0 && "Unknown return instruction!");
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case 3:
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assert(0 && "Not yet handled return instruction!");
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break;
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case 2: {
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SDOperand Val = Select(N->getOperand(1));
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switch (N->getOperand(1).getValueType()) {
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default:
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assert(0 && "All other types should have been promoted!!");
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case MVT::i32:
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Chain = CurDAG->getCopyToReg(Chain, X86::EAX, Val);
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break;
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case MVT::f32:
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case MVT::f64:
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assert(0 && "Not yet handled return instruction!");
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break;
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}
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}
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case 1:
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break;
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}
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if (X86Lowering.getBytesToPopOnReturn() == 0)
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CurDAG->SelectNodeTo(N, X86::RET, MVT::Other, Chain);
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else
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CurDAG->SelectNodeTo(N, X86::RET, MVT::Other, Chain,
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getI16Imm(X86Lowering.getBytesToPopOnReturn()));
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return SDOperand(N, 0);
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}
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}
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return SelectCode(Op);
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}
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/// createX86ISelDag - This pass converts a legalized DAG into a
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/// X86-specific DAG, ready for instruction scheduling.
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///
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FunctionPass *llvm::createX86ISelDag(TargetMachine &TM) {
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return new X86DAGToDAGISel(TM);
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}
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