1//===- lib/MC/MCWasmStreamer.cpp - Wasm Object Output ---------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file assembles .s files and emits Wasm .o object files.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/MC/MCWasmStreamer.h"
14#include "llvm/ADT/SmallString.h"
15#include "llvm/ADT/SmallVector.h"
16#include "llvm/MC/MCAsmBackend.h"
17#include "llvm/MC/MCAssembler.h"
18#include "llvm/MC/MCCodeEmitter.h"
19#include "llvm/MC/MCExpr.h"
20#include "llvm/MC/MCFixup.h"
21#include "llvm/MC/MCObjectStreamer.h"
22#include "llvm/MC/MCSection.h"
23#include "llvm/MC/MCSectionWasm.h"
24#include "llvm/MC/MCSymbol.h"
25#include "llvm/MC/MCSymbolWasm.h"
26#include "llvm/MC/TargetRegistry.h"
27#include "llvm/Support/Casting.h"
28#include "llvm/Support/ErrorHandling.h"
29
30namespace llvm {
31class MCContext;
32class MCStreamer;
33class MCSubtargetInfo;
34} // namespace llvm
35
36using namespace llvm;
37
38MCWasmStreamer::~MCWasmStreamer() = default; // anchor.
39
40void MCWasmStreamer::emitLabel(MCSymbol *S, SMLoc Loc) {
41 auto *Symbol = cast<MCSymbolWasm>(Val: S);
42 MCObjectStreamer::emitLabel(Symbol, Loc);
43
44 const MCSectionWasm &Section =
45 static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
46 if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
47 Symbol->setTLS();
48}
49
50void MCWasmStreamer::emitLabelAtPos(MCSymbol *S, SMLoc Loc, MCDataFragment &F,
51 uint64_t Offset) {
52 auto *Symbol = cast<MCSymbolWasm>(Val: S);
53 MCObjectStreamer::emitLabelAtPos(Symbol, Loc, F, Offset);
54
55 const MCSectionWasm &Section =
56 static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
57 if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
58 Symbol->setTLS();
59}
60
61void MCWasmStreamer::changeSection(MCSection *Section, uint32_t Subsection) {
62 MCAssembler &Asm = getAssembler();
63 auto *SectionWasm = cast<MCSectionWasm>(Val: Section);
64 const MCSymbol *Grp = SectionWasm->getGroup();
65 if (Grp)
66 Asm.registerSymbol(Symbol: *Grp);
67
68 this->MCObjectStreamer::changeSection(Section, Subsection);
69 Asm.registerSymbol(Symbol: *Section->getBeginSymbol());
70}
71
72bool MCWasmStreamer::emitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
73 assert(Attribute != MCSA_IndirectSymbol && "indirect symbols not supported");
74
75 auto *Symbol = cast<MCSymbolWasm>(Val: S);
76
77 // Adding a symbol attribute always introduces the symbol; note that an
78 // important side effect of calling registerSymbol here is to register the
79 // symbol with the assembler.
80 getAssembler().registerSymbol(Symbol: *Symbol);
81
82 switch (Attribute) {
83 case MCSA_LazyReference:
84 case MCSA_Reference:
85 case MCSA_SymbolResolver:
86 case MCSA_PrivateExtern:
87 case MCSA_WeakDefinition:
88 case MCSA_WeakDefAutoPrivate:
89 case MCSA_Invalid:
90 case MCSA_IndirectSymbol:
91 case MCSA_Protected:
92 case MCSA_Exported:
93 return false;
94
95 case MCSA_Hidden:
96 Symbol->setHidden(true);
97 break;
98
99 case MCSA_Weak:
100 case MCSA_WeakReference:
101 Symbol->setWeak(true);
102 Symbol->setExternal(true);
103 break;
104
105 case MCSA_Global:
106 Symbol->setExternal(true);
107 break;
108
109 case MCSA_ELF_TypeFunction:
110 Symbol->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
111 break;
112
113 case MCSA_ELF_TypeTLS:
114 Symbol->setTLS();
115 break;
116
117 case MCSA_ELF_TypeObject:
118 case MCSA_Cold:
119 break;
120
121 case MCSA_NoDeadStrip:
122 Symbol->setNoStrip();
123 break;
124
125 default:
126 // unrecognized directive
127 llvm_unreachable("unexpected MCSymbolAttr");
128 return false;
129 }
130
131 return true;
132}
133
134void MCWasmStreamer::emitCommonSymbol(MCSymbol *S, uint64_t Size,
135 Align ByteAlignment) {
136 llvm_unreachable("Common symbols are not yet implemented for Wasm");
137}
138
139void MCWasmStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
140 cast<MCSymbolWasm>(Val: Symbol)->setSize(Value);
141}
142
143void MCWasmStreamer::emitLocalCommonSymbol(MCSymbol *S, uint64_t Size,
144 Align ByteAlignment) {
145 llvm_unreachable("Local common symbols are not yet implemented for Wasm");
146}
147
148void MCWasmStreamer::emitIdent(StringRef IdentString) {
149 // TODO(sbc): Add the ident section once we support mergable strings
150 // sections in the object format
151}
152
153void MCWasmStreamer::finishImpl() {
154 emitFrames(MAB: nullptr);
155
156 this->MCObjectStreamer::finishImpl();
157}
158
159MCStreamer *llvm::createWasmStreamer(MCContext &Context,
160 std::unique_ptr<MCAsmBackend> &&MAB,
161 std::unique_ptr<MCObjectWriter> &&OW,
162 std::unique_ptr<MCCodeEmitter> &&CE) {
163 MCWasmStreamer *S =
164 new MCWasmStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
165 return S;
166}
167