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      1 //===- AMDGPUMCInstLower.cpp - Lower AMDGPU MachineInstr to an MCInst -----===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 /// \file
     11 /// \brief Code to lower AMDGPU MachineInstrs to their corresponding MCInst.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 //
     15 
     16 #include "AMDGPUMCInstLower.h"
     17 #include "AMDGPUAsmPrinter.h"
     18 #include "AMDGPUTargetMachine.h"
     19 #include "InstPrinter/AMDGPUInstPrinter.h"
     20 #include "R600InstrInfo.h"
     21 #include "SIInstrInfo.h"
     22 #include "llvm/CodeGen/MachineBasicBlock.h"
     23 #include "llvm/CodeGen/MachineInstr.h"
     24 #include "llvm/IR/Constants.h"
     25 #include "llvm/IR/Function.h"
     26 #include "llvm/IR/GlobalVariable.h"
     27 #include "llvm/MC/MCCodeEmitter.h"
     28 #include "llvm/MC/MCContext.h"
     29 #include "llvm/MC/MCExpr.h"
     30 #include "llvm/MC/MCInst.h"
     31 #include "llvm/MC/MCObjectStreamer.h"
     32 #include "llvm/MC/MCStreamer.h"
     33 #include "llvm/Support/ErrorHandling.h"
     34 #include "llvm/Support/Format.h"
     35 #include <algorithm>
     36 
     37 using namespace llvm;
     38 
     39 AMDGPUMCInstLower::AMDGPUMCInstLower(MCContext &ctx, const AMDGPUSubtarget &st):
     40   Ctx(ctx), ST(st)
     41 { }
     42 
     43 void AMDGPUMCInstLower::lower(const MachineInstr *MI, MCInst &OutMI) const {
     44 
     45   int MCOpcode = ST.getInstrInfo()->pseudoToMCOpcode(MI->getOpcode());
     46 
     47   if (MCOpcode == -1) {
     48     LLVMContext &C = MI->getParent()->getParent()->getFunction()->getContext();
     49     C.emitError("AMDGPUMCInstLower::lower - Pseudo instruction doesn't have "
     50                 "a target-specific version: " + Twine(MI->getOpcode()));
     51   }
     52 
     53   OutMI.setOpcode(MCOpcode);
     54 
     55   for (const MachineOperand &MO : MI->explicit_operands()) {
     56     MCOperand MCOp;
     57     switch (MO.getType()) {
     58     default:
     59       llvm_unreachable("unknown operand type");
     60     case MachineOperand::MO_Immediate:
     61       MCOp = MCOperand::createImm(MO.getImm());
     62       break;
     63     case MachineOperand::MO_Register:
     64       MCOp = MCOperand::createReg(AMDGPU::getMCReg(MO.getReg(), ST));
     65       break;
     66     case MachineOperand::MO_MachineBasicBlock:
     67       MCOp = MCOperand::createExpr(MCSymbolRefExpr::create(
     68                                    MO.getMBB()->getSymbol(), Ctx));
     69       break;
     70     case MachineOperand::MO_GlobalAddress: {
     71       const GlobalValue *GV = MO.getGlobal();
     72       MCSymbol *Sym = Ctx.getOrCreateSymbol(StringRef(GV->getName()));
     73       MCOp = MCOperand::createExpr(MCSymbolRefExpr::create(Sym, Ctx));
     74       break;
     75     }
     76     case MachineOperand::MO_ExternalSymbol: {
     77       MCSymbol *Sym = Ctx.getOrCreateSymbol(StringRef(MO.getSymbolName()));
     78       const MCSymbolRefExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx);
     79       MCOp = MCOperand::createExpr(Expr);
     80       break;
     81     }
     82     }
     83     OutMI.addOperand(MCOp);
     84   }
     85 }
     86 
     87 void AMDGPUAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     88   const AMDGPUSubtarget &STI = MF->getSubtarget<AMDGPUSubtarget>();
     89   AMDGPUMCInstLower MCInstLowering(OutContext, STI);
     90 
     91 #ifdef _DEBUG
     92   StringRef Err;
     93   if (!STI.getInstrInfo()->verifyInstruction(MI, Err)) {
     94     errs() << "Warning: Illegal instruction detected: " << Err << "\n";
     95     MI->dump();
     96   }
     97 #endif
     98   if (MI->isBundle()) {
     99     const MachineBasicBlock *MBB = MI->getParent();
    100     MachineBasicBlock::const_instr_iterator I = ++MI->getIterator();
    101     while (I != MBB->instr_end() && I->isInsideBundle()) {
    102       EmitInstruction(&*I);
    103       ++I;
    104     }
    105   } else {
    106     MCInst TmpInst;
    107     MCInstLowering.lower(MI, TmpInst);
    108     EmitToStreamer(*OutStreamer, TmpInst);
    109 
    110     if (STI.dumpCode()) {
    111       // Disassemble instruction/operands to text.
    112       DisasmLines.resize(DisasmLines.size() + 1);
    113       std::string &DisasmLine = DisasmLines.back();
    114       raw_string_ostream DisasmStream(DisasmLine);
    115 
    116       AMDGPUInstPrinter InstPrinter(*TM.getMCAsmInfo(),
    117                                     *MF->getSubtarget().getInstrInfo(),
    118                                     *MF->getSubtarget().getRegisterInfo());
    119       InstPrinter.printInst(&TmpInst, DisasmStream, StringRef(),
    120                             MF->getSubtarget());
    121 
    122       // Disassemble instruction/operands to hex representation.
    123       SmallVector<MCFixup, 4> Fixups;
    124       SmallVector<char, 16> CodeBytes;
    125       raw_svector_ostream CodeStream(CodeBytes);
    126 
    127       auto &ObjStreamer = static_cast<MCObjectStreamer&>(*OutStreamer);
    128       MCCodeEmitter &InstEmitter = ObjStreamer.getAssembler().getEmitter();
    129       InstEmitter.encodeInstruction(TmpInst, CodeStream, Fixups,
    130                                     MF->getSubtarget<MCSubtargetInfo>());
    131       HexLines.resize(HexLines.size() + 1);
    132       std::string &HexLine = HexLines.back();
    133       raw_string_ostream HexStream(HexLine);
    134 
    135       for (size_t i = 0; i < CodeBytes.size(); i += 4) {
    136         unsigned int CodeDWord = *(unsigned int *)&CodeBytes[i];
    137         HexStream << format("%s%08X", (i > 0 ? " " : ""), CodeDWord);
    138       }
    139 
    140       DisasmStream.flush();
    141       DisasmLineMaxLen = std::max(DisasmLineMaxLen, DisasmLine.size());
    142     }
    143   }
    144 }
    145