forked from OSchip/llvm-project
116 lines
4.2 KiB
C++
116 lines
4.2 KiB
C++
// WebAssemblyMCInstLower.cpp - Convert WebAssembly MachineInstr to an MCInst //
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief This file contains code to lower WebAssembly MachineInstrs to their
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/// corresponding MCInst records.
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///
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//===----------------------------------------------------------------------===//
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#include "WebAssemblyMCInstLower.h"
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#include "WebAssemblyMachineFunctionInfo.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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MCSymbol *
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WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
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return Printer.getSymbol(MO.getGlobal());
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}
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MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol(
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const MachineOperand &MO) const {
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return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
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}
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MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(MCSymbol *Sym,
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int64_t Offset,
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bool IsFunc) const {
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MCSymbolRefExpr::VariantKind VK =
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IsFunc ? MCSymbolRefExpr::VK_WebAssembly_FUNCTION
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: MCSymbolRefExpr::VK_None;
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const MCExpr *Expr = MCSymbolRefExpr::create(Sym, VK, Ctx);
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if (Offset != 0) {
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if (IsFunc)
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report_fatal_error("Function addresses with offsets not supported");
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Expr =
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MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(Offset, Ctx), Ctx);
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}
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return MCOperand::createExpr(Expr);
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}
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void WebAssemblyMCInstLower::Lower(const MachineInstr *MI,
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MCInst &OutMI) const {
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OutMI.setOpcode(MI->getOpcode());
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for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
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const MachineOperand &MO = MI->getOperand(i);
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MCOperand MCOp;
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switch (MO.getType()) {
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default:
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MI->dump();
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llvm_unreachable("unknown operand type");
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case MachineOperand::MO_MachineBasicBlock:
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MI->dump();
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llvm_unreachable("MachineBasicBlock operand should have been rewritten");
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case MachineOperand::MO_Register: {
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// Ignore all implicit register operands.
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if (MO.isImplicit())
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continue;
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const WebAssemblyFunctionInfo &MFI =
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*MI->getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>();
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unsigned WAReg = MFI.getWAReg(MO.getReg());
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MCOp = MCOperand::createReg(WAReg);
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break;
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}
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case MachineOperand::MO_Immediate:
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MCOp = MCOperand::createImm(MO.getImm());
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break;
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case MachineOperand::MO_FPImmediate: {
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// TODO: MC converts all floating point immediate operands to double.
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// This is fine for numeric values, but may cause NaNs to change bits.
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const ConstantFP *Imm = MO.getFPImm();
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if (Imm->getType()->isFloatTy())
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MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToFloat());
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else if (Imm->getType()->isDoubleTy())
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MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToDouble());
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else
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llvm_unreachable("unknown floating point immediate type");
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break;
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}
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case MachineOperand::MO_GlobalAddress:
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assert(MO.getTargetFlags() == 0 &&
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"WebAssembly does not use target flags on GlobalAddresses");
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MCOp = LowerSymbolOperand(GetGlobalAddressSymbol(MO), MO.getOffset(),
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MO.getGlobal()->getValueType()->isFunctionTy());
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break;
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case MachineOperand::MO_ExternalSymbol:
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// The target flag indicates whether this is a symbol for a
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// variable or a function.
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assert((MO.getTargetFlags() & -2) == 0 &&
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"WebAssembly uses only one target flag bit on ExternalSymbols");
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MCOp = LowerSymbolOperand(GetExternalSymbolSymbol(MO), /*Offset=*/0,
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MO.getTargetFlags() & 1);
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break;
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}
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OutMI.addOperand(MCOp);
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}
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}
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