WebAssemblyMCInstLower.cpp revision 292915
1// WebAssemblyMCInstLower.cpp - Convert WebAssembly 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 This file contains code to lower WebAssembly MachineInstrs to their 12/// corresponding MCInst records. 13/// 14//===----------------------------------------------------------------------===// 15 16#include "WebAssemblyMCInstLower.h" 17#include "WebAssemblyMachineFunctionInfo.h" 18#include "llvm/CodeGen/AsmPrinter.h" 19#include "llvm/CodeGen/MachineFunction.h" 20#include "llvm/IR/Constants.h" 21#include "llvm/MC/MCAsmInfo.h" 22#include "llvm/MC/MCContext.h" 23#include "llvm/MC/MCExpr.h" 24#include "llvm/MC/MCInst.h" 25#include "llvm/Support/ErrorHandling.h" 26#include "llvm/Support/raw_ostream.h" 27using namespace llvm; 28 29MCSymbol * 30WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const { 31 return Printer.getSymbol(MO.getGlobal()); 32} 33 34MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol( 35 const MachineOperand &MO) const { 36 return Printer.GetExternalSymbolSymbol(MO.getSymbolName()); 37} 38 39MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(const MachineOperand &MO, 40 MCSymbol *Sym) const { 41 assert(MO.getTargetFlags() == 0 && "WebAssembly does not use target flags"); 42 43 const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx); 44 45 int64_t Offset = MO.getOffset(); 46 if (Offset != 0) { 47 assert(!MO.isJTI() && "Unexpected offset with jump table index"); 48 Expr = 49 MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(Offset, Ctx), Ctx); 50 } 51 52 return MCOperand::createExpr(Expr); 53} 54 55void WebAssemblyMCInstLower::Lower(const MachineInstr *MI, 56 MCInst &OutMI) const { 57 OutMI.setOpcode(MI->getOpcode()); 58 59 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 60 const MachineOperand &MO = MI->getOperand(i); 61 62 MCOperand MCOp; 63 switch (MO.getType()) { 64 default: 65 MI->dump(); 66 llvm_unreachable("unknown operand type"); 67 case MachineOperand::MO_Register: { 68 // Ignore all implicit register operands. 69 if (MO.isImplicit()) 70 continue; 71 const WebAssemblyFunctionInfo &MFI = 72 *MI->getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>(); 73 unsigned WAReg = MFI.getWAReg(MO.getReg()); 74 MCOp = MCOperand::createReg(WAReg); 75 break; 76 } 77 case MachineOperand::MO_Immediate: 78 MCOp = MCOperand::createImm(MO.getImm()); 79 break; 80 case MachineOperand::MO_FPImmediate: { 81 // TODO: MC converts all floating point immediate operands to double. 82 // This is fine for numeric values, but may cause NaNs to change bits. 83 const ConstantFP *Imm = MO.getFPImm(); 84 if (Imm->getType()->isFloatTy()) 85 MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToFloat()); 86 else if (Imm->getType()->isDoubleTy()) 87 MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToDouble()); 88 else 89 llvm_unreachable("unknown floating point immediate type"); 90 break; 91 } 92 case MachineOperand::MO_MachineBasicBlock: 93 MCOp = MCOperand::createExpr( 94 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx)); 95 break; 96 case MachineOperand::MO_GlobalAddress: 97 MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO)); 98 break; 99 case MachineOperand::MO_ExternalSymbol: 100 MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO)); 101 break; 102 } 103 104 OutMI.addOperand(MCOp); 105 } 106} 107