1 //=- WebAssemblyMCCodeEmitter.cpp - Convert WebAssembly code to machine code -//
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 implements the WebAssemblyMCCodeEmitter class.
12 ///
13 //===----------------------------------------------------------------------===//
14
15 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/ADT/Statistic.h"
18 #include "llvm/MC/MCCodeEmitter.h"
19 #include "llvm/MC/MCFixup.h"
20 #include "llvm/MC/MCInst.h"
21 #include "llvm/MC/MCInstrInfo.h"
22 #include "llvm/MC/MCRegisterInfo.h"
23 #include "llvm/MC/MCSubtargetInfo.h"
24 #include "llvm/MC/MCSymbol.h"
25 #include "llvm/Support/EndianStream.h"
26 #include "llvm/Support/raw_ostream.h"
27 using namespace llvm;
28
29 #define DEBUG_TYPE "mccodeemitter"
30
31 STATISTIC(MCNumEmitted, "Number of MC instructions emitted.");
32 STATISTIC(MCNumFixups, "Number of MC fixups created.");
33
34 namespace {
35 class WebAssemblyMCCodeEmitter final : public MCCodeEmitter {
36 const MCInstrInfo &MCII;
37
38 // Implementation generated by tablegen.
39 uint64_t getBinaryCodeForInstr(const MCInst &MI,
40 SmallVectorImpl<MCFixup> &Fixups,
41 const MCSubtargetInfo &STI) const;
42
43 void encodeInstruction(const MCInst &MI, raw_ostream &OS,
44 SmallVectorImpl<MCFixup> &Fixups,
45 const MCSubtargetInfo &STI) const override;
46
47 public:
WebAssemblyMCCodeEmitter(const MCInstrInfo & mcii)48 WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii) : MCII(mcii) {}
49 };
50 } // end anonymous namespace
51
createWebAssemblyMCCodeEmitter(const MCInstrInfo & MCII)52 MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII) {
53 return new WebAssemblyMCCodeEmitter(MCII);
54 }
55
encodeInstruction(const MCInst & MI,raw_ostream & OS,SmallVectorImpl<MCFixup> & Fixups,const MCSubtargetInfo & STI) const56 void WebAssemblyMCCodeEmitter::encodeInstruction(
57 const MCInst &MI, raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
58 const MCSubtargetInfo &STI) const {
59 // FIXME: This is not the real binary encoding. This is an extremely
60 // over-simplified encoding where we just use uint64_t for everything. This
61 // is a temporary measure.
62 support::endian::Writer<support::little>(OS).write<uint64_t>(MI.getOpcode());
63 const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
64 if (Desc.isVariadic())
65 support::endian::Writer<support::little>(OS).write<uint64_t>(
66 MI.getNumOperands() - Desc.NumOperands);
67 for (unsigned i = 0, e = MI.getNumOperands(); i < e; ++i) {
68 const MCOperand &MO = MI.getOperand(i);
69 if (MO.isReg()) {
70 support::endian::Writer<support::little>(OS).write<uint64_t>(MO.getReg());
71 } else if (MO.isImm()) {
72 support::endian::Writer<support::little>(OS).write<uint64_t>(MO.getImm());
73 } else if (MO.isFPImm()) {
74 support::endian::Writer<support::little>(OS).write<double>(MO.getFPImm());
75 } else if (MO.isExpr()) {
76 support::endian::Writer<support::little>(OS).write<uint64_t>(0);
77 Fixups.push_back(MCFixup::create(
78 (1 + MCII.get(MI.getOpcode()).isVariadic() + i) * sizeof(uint64_t),
79 MO.getExpr(),
80 STI.getTargetTriple().isArch64Bit() ? FK_Data_8 : FK_Data_4,
81 MI.getLoc()));
82 ++MCNumFixups;
83 } else {
84 llvm_unreachable("unexpected operand kind");
85 }
86 }
87
88 ++MCNumEmitted; // Keep track of the # of mi's emitted.
89 }
90
91 #include "WebAssemblyGenMCCodeEmitter.inc"
92