LLVM 19.0.0git
MCWasmStreamer.cpp
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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
17#include "llvm/MC/MCAssembler.h"
19#include "llvm/MC/MCExpr.h"
20#include "llvm/MC/MCFixup.h"
21#include "llvm/MC/MCFragment.h"
23#include "llvm/MC/MCSection.h"
25#include "llvm/MC/MCSymbol.h"
31
32namespace llvm {
33class MCContext;
34class MCStreamer;
35class MCSubtargetInfo;
36} // namespace llvm
37
38using namespace llvm;
39
40MCWasmStreamer::~MCWasmStreamer() = default; // anchor.
41
43 auto *Symbol = cast<MCSymbolWasm>(S);
44 MCObjectStreamer::emitLabel(Symbol, Loc);
45
46 const MCSectionWasm &Section =
47 static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
48 if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
49 Symbol->setTLS();
50}
51
54 auto *Symbol = cast<MCSymbolWasm>(S);
56
57 const MCSectionWasm &Section =
58 static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
59 if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
60 Symbol->setTLS();
61}
62
64 // Let the target do whatever target specific stuff it needs to do.
66
67 // Do any generic stuff we need to do.
68 llvm_unreachable("invalid assembler flag!");
69}
70
72 const MCExpr *Subsection) {
74 auto *SectionWasm = cast<MCSectionWasm>(Section);
75 const MCSymbol *Grp = SectionWasm->getGroup();
76 if (Grp)
77 Asm.registerSymbol(*Grp);
78
79 this->MCObjectStreamer::changeSection(Section, Subsection);
80 Asm.registerSymbol(*Section->getBeginSymbol());
81}
82
84 const MCSymbol *Symbol) {
88 Alias->setVariableValue(Value);
89}
90
92 assert(Attribute != MCSA_IndirectSymbol && "indirect symbols not supported");
93
94 auto *Symbol = cast<MCSymbolWasm>(S);
95
96 // Adding a symbol attribute always introduces the symbol; note that an
97 // important side effect of calling registerSymbol here is to register the
98 // symbol with the assembler.
100
101 switch (Attribute) {
103 case MCSA_Reference:
108 case MCSA_Invalid:
110 case MCSA_Protected:
111 case MCSA_Exported:
112 return false;
113
114 case MCSA_Hidden:
115 Symbol->setHidden(true);
116 break;
117
118 case MCSA_Weak:
120 Symbol->setWeak(true);
121 Symbol->setExternal(true);
122 break;
123
124 case MCSA_Global:
125 Symbol->setExternal(true);
126 break;
127
129 Symbol->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
130 break;
131
132 case MCSA_ELF_TypeTLS:
133 Symbol->setTLS();
134 break;
135
137 case MCSA_Cold:
138 break;
139
140 case MCSA_NoDeadStrip:
141 Symbol->setNoStrip();
142 break;
143
144 default:
145 // unrecognized directive
146 llvm_unreachable("unexpected MCSymbolAttr");
147 return false;
148 }
149
150 return true;
151}
152
154 Align ByteAlignment) {
155 llvm_unreachable("Common symbols are not yet implemented for Wasm");
156}
157
159 cast<MCSymbolWasm>(Symbol)->setSize(Value);
160}
161
163 Align ByteAlignment) {
164 llvm_unreachable("Local common symbols are not yet implemented for Wasm");
165}
166
168 // TODO(sbc): Add the ident section once we support mergable strings
169 // sections in the object format
170}
171
172void MCWasmStreamer::emitInstToFragment(const MCInst &Inst,
173 const MCSubtargetInfo &STI) {
175 MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
176
177 for (auto &Fixup : F.getFixups())
178 fixSymbolsInTLSFixups(Fixup.getValue());
179}
180
181void MCWasmStreamer::emitInstToData(const MCInst &Inst,
182 const MCSubtargetInfo &STI) {
183 MCAssembler &Assembler = getAssembler();
185 SmallString<256> Code;
186 Assembler.getEmitter().encodeInstruction(Inst, Code, Fixups, STI);
187
188 for (auto &Fixup : Fixups)
189 fixSymbolsInTLSFixups(Fixup.getValue());
190
191 // Append the encoded instruction to the current data fragment (or create a
192 // new such fragment if the current fragment is not a data fragment).
194
195 // Add the fixups and data.
196 for (unsigned I = 0, E = Fixups.size(); I != E; ++I) {
197 Fixups[I].setOffset(Fixups[I].getOffset() + DF->getContents().size());
198 DF->getFixups().push_back(Fixups[I]);
199 }
200 DF->setHasInstructions(STI);
201 DF->getContents().append(Code.begin(), Code.end());
202}
203
205 emitFrames(nullptr);
206
208}
209
210void MCWasmStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
211 switch (expr->getKind()) {
212 case MCExpr::Target:
213 case MCExpr::Constant:
214 break;
215
216 case MCExpr::Binary: {
217 const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
218 fixSymbolsInTLSFixups(be->getLHS());
219 fixSymbolsInTLSFixups(be->getRHS());
220 break;
221 }
222
223 case MCExpr::SymbolRef: {
224 const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
225 switch (symRef.getKind()) {
229 cast<MCSymbolWasm>(symRef.getSymbol()).setTLS();
230 break;
231 default:
232 break;
233 }
234 break;
235 }
236
237 case MCExpr::Unary:
238 fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
239 break;
240 }
241}
242
244 llvm_unreachable("Generic Wasm doesn't support this directive");
245}
246
247void MCWasmStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
248 llvm_unreachable("Wasm doesn't support this directive");
249}
250
252 uint64_t Size, Align ByteAlignment,
253 SMLoc Loc) {
254 llvm_unreachable("Wasm doesn't support this directive");
255}
256
258 uint64_t Size, Align ByteAlignment) {
259 llvm_unreachable("Wasm doesn't support this directive");
260}
261
263 std::unique_ptr<MCAsmBackend> &&MAB,
264 std::unique_ptr<MCObjectWriter> &&OW,
265 std::unique_ptr<MCCodeEmitter> &&CE) {
266 MCWasmStreamer *S =
267 new MCWasmStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
268 return S;
269}
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
static RegisterPass< DebugifyFunctionPass > DF("debugify-function", "Attach debug info to a function")
uint64_t Size
#define F(x, y, z)
Definition: MD5.cpp:55
#define I(x, y, z)
Definition: MD5.cpp:58
PowerPC TLS Dynamic Call Fixup
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file defines the SmallString class.
This file defines the SmallVector class.
virtual void handleAssemblerFlag(MCAssemblerFlag Flag)
Handle any target-specific assembler flags. By default, do nothing.
Definition: MCAsmBackend.h:232
MCCodeEmitter & getEmitter() const
Definition: MCAssembler.h:332
MCAsmBackend & getBackend() const
Definition: MCAssembler.h:330
bool registerSymbol(const MCSymbol &Symbol)
Binary assembler expressions.
Definition: MCExpr.h:492
const MCExpr * getLHS() const
Get the left-hand side expression of the binary operator.
Definition: MCExpr.h:639
const MCExpr * getRHS() const
Get the right-hand side expression of the binary operator.
Definition: MCExpr.h:642
virtual void encodeInstruction(const MCInst &Inst, SmallVectorImpl< char > &CB, SmallVectorImpl< MCFixup > &Fixups, const MCSubtargetInfo &STI) const =0
Encode the given Inst to bytes and append to CB.
Context object for machine code objects.
Definition: MCContext.h:83
Fragment for data and encoded instructions.
Definition: MCFragment.h:235
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
@ Unary
Unary expressions.
Definition: MCExpr.h:41
@ Constant
Constant expressions.
Definition: MCExpr.h:39
@ SymbolRef
References to labels and assigned expressions.
Definition: MCExpr.h:40
@ Target
Target specific expression.
Definition: MCExpr.h:42
@ Binary
Binary expressions.
Definition: MCExpr.h:38
ExprKind getKind() const
Definition: MCExpr.h:81
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:184
MCDataFragment * getOrCreateDataFragment(const MCSubtargetInfo *STI=nullptr)
Get a data fragment to write into, creating a new one if the current fragment is not a data fragment.
MCAssembler & getAssembler()
virtual void emitLabelAtPos(MCSymbol *Symbol, SMLoc Loc, MCFragment *F, uint64_t Offset)
virtual void emitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &)
Emit an instruction to a special fragment, because this instruction can change its size during relaxa...
void emitLabel(MCSymbol *Symbol, SMLoc Loc=SMLoc()) override
Emit a label for Symbol into the current section.
void finishImpl() override
Streamer specific finalization.
MCFragment * getCurrentFragment() const
void emitFrames(MCAsmBackend *MAB)
void changeSection(MCSection *Section, const MCExpr *Subsection) override
Update streamer for a new active section.
A relaxable fragment holds on to its MCInst, since it may need to be relaxed during the assembler lay...
Definition: MCFragment.h:267
This represents a section on wasm.
Definition: MCSectionWasm.h:26
Instances of this class represent a uniqued identifier for a section in the current translation unit.
Definition: MCSection.h:35
Streaming machine code generation interface.
Definition: MCStreamer.h:212
MCContext & getContext() const
Definition: MCStreamer.h:297
MCSection * getCurrentSectionOnly() const
Definition: MCStreamer.h:395
Generic base class for all target subtargets.
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:192
const MCSymbol & getSymbol() const
Definition: MCExpr.h:410
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:397
VariantKind getKind() const
Definition: MCExpr.h:412
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
void setVariableValue(const MCExpr *Value)
Definition: MCSymbol.cpp:47
void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size, Align ByteAlignment) override
Emit a common symbol.
void emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size, Align ByteAlignment) override
Emit a local common (.lcomm) symbol.
void emitIdent(StringRef IdentString) override
Emit the "identifiers" directive.
void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override
Set the DescValue for the Symbol.
void emitLabel(MCSymbol *Symbol, SMLoc Loc=SMLoc()) override
Emit a label for Symbol into the current section.
void emitThumbFunc(MCSymbol *Func) override
Note in the output that the specified Func is a Thumb mode function (ARM target only).
~MCWasmStreamer() override
void finishImpl() override
Streamer specific finalization.
void emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol, uint64_t Size, Align ByteAlignment=Align(1)) override
Emit a thread local bss (.tbss) symbol.
void emitLabelAtPos(MCSymbol *Symbol, SMLoc Loc, MCFragment *F, uint64_t Offset) override
void emitELFSize(MCSymbol *Symbol, const MCExpr *Value) override
Emit an ELF .size directive.
void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override
Emit an weak reference from Alias to Symbol.
void changeSection(MCSection *Section, const MCExpr *Subsection) override
Update streamer for a new active section.
bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override
Add the given Attribute to Symbol.
void emitZerofill(MCSection *Section, MCSymbol *Symbol=nullptr, uint64_t Size=0, Align ByteAlignment=Align(1), SMLoc Loc=SMLoc()) override
Emit the zerofill section and an optional symbol.
void emitAssemblerFlag(MCAssemblerFlag Flag) override
Note in the output the specified Flag.
Represents a location in source code.
Definition: SMLoc.h:23
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:26
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1209
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
LLVM Value Representation.
Definition: Value.h:74
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
NodeAddr< CodeNode * > Code
Definition: RDFGraph.h:388
@ WASM_SYMBOL_TYPE_FUNCTION
Definition: Wasm.h:209
@ WASM_SEG_FLAG_TLS
Definition: Wasm.h:219
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ Offset
Definition: DWP.cpp:456
static Error getOffset(const SymbolRef &Sym, SectionRef Sec, uint64_t &Result)
MCAssemblerFlag
Definition: MCDirectives.h:53
MCStreamer * createWasmStreamer(MCContext &Ctx, std::unique_ptr< MCAsmBackend > &&TAB, std::unique_ptr< MCObjectWriter > &&OW, std::unique_ptr< MCCodeEmitter > &&CE)
MCSymbolAttr
Definition: MCDirectives.h:18
@ MCSA_WeakDefAutoPrivate
.weak_def_can_be_hidden (MachO)
Definition: MCDirectives.h:48
@ MCSA_Protected
.protected (ELF)
Definition: MCDirectives.h:43
@ MCSA_Exported
.globl _foo, exported (XCOFF)
Definition: MCDirectives.h:34
@ MCSA_PrivateExtern
.private_extern (MachO)
Definition: MCDirectives.h:42
@ MCSA_WeakReference
.weak_reference (MachO)
Definition: MCDirectives.h:47
@ MCSA_LazyReference
.lazy_reference (MachO)
Definition: MCDirectives.h:37
@ MCSA_Reference
.reference (MachO)
Definition: MCDirectives.h:44
@ MCSA_SymbolResolver
.symbol_resolver (MachO)
Definition: MCDirectives.h:40
@ MCSA_Weak
.weak
Definition: MCDirectives.h:45
@ MCSA_ELF_TypeTLS
.type _foo, STT_TLS # aka @tls_object
Definition: MCDirectives.h:26
@ MCSA_IndirectSymbol
.indirect_symbol (MachO)
Definition: MCDirectives.h:35
@ MCSA_WeakDefinition
.weak_definition (MachO)
Definition: MCDirectives.h:46
@ MCSA_Global
.type _foo, @gnu_unique_object
Definition: MCDirectives.h:30
@ MCSA_Cold
.cold (MachO)
Definition: MCDirectives.h:22
@ MCSA_ELF_TypeObject
.type _foo, STT_OBJECT # aka @object
Definition: MCDirectives.h:25
@ MCSA_ELF_TypeFunction
.type _foo, STT_FUNC # aka @function
Definition: MCDirectives.h:23
@ MCSA_Hidden
.hidden (ELF)
Definition: MCDirectives.h:33
@ MCSA_Invalid
Not a valid directive.
Definition: MCDirectives.h:19
@ MCSA_NoDeadStrip
.no_dead_strip (MachO)
Definition: MCDirectives.h:39
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39