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 "llvm/ADT/SmallString.h"
18 #include "llvm/IR/Constants.h"
19 #include "llvm/CodeGen/AsmPrinter.h"
20 #include "llvm/CodeGen/MachineBasicBlock.h"
21 #include "llvm/CodeGen/MachineInstr.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCExpr.h"
25 #include "llvm/MC/MCInst.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/raw_ostream.h"
28 using namespace llvm;
29 
30 MCSymbol *
31 WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
32   return Printer.getSymbol(MO.getGlobal());
33 }
34 
35 MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
36                                                      MCSymbol *Sym) const {
37 
38   const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx);
39 
40   if (!MO.isJTI() && MO.getOffset())
41     llvm_unreachable("unknown symbol op");
42 
43   return MCOperand::createExpr(Expr);
44 }
45 
46 void WebAssemblyMCInstLower::Lower(const MachineInstr *MI,
47                                    MCInst &OutMI) const {
48   OutMI.setOpcode(MI->getOpcode());
49 
50   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
51     const MachineOperand &MO = MI->getOperand(i);
52 
53     MCOperand MCOp;
54     switch (MO.getType()) {
55     default:
56       MI->dump();
57       llvm_unreachable("unknown operand type");
58     case MachineOperand::MO_Register:
59       // Ignore all implicit register operands.
60       if (MO.isImplicit())
61         continue;
62       MCOp = MCOperand::createReg(MO.getReg());
63       break;
64     case MachineOperand::MO_Immediate:
65       MCOp = MCOperand::createImm(MO.getImm());
66       break;
67     case MachineOperand::MO_FPImmediate:
68       MCOp = MCOperand::createFPImm(
69           MO.getFPImm()->getValueAPF().convertToDouble());
70       break;
71     case MachineOperand::MO_MachineBasicBlock:
72       MCOp = MCOperand::createExpr(
73           MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx));
74       break;
75     case MachineOperand::MO_RegisterMask:
76       continue;
77     case MachineOperand::MO_GlobalAddress:
78       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
79       break;
80     }
81 
82     OutMI.addOperand(MCOp);
83   }
84 }
85