1//===- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info ---===//
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 implements classes used to handle lowerings specific to common
10// object file formats.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
15#include "llvm/ADT/SmallString.h"
16#include "llvm/ADT/SmallVector.h"
17#include "llvm/ADT/StringExtras.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/BinaryFormat/COFF.h"
20#include "llvm/BinaryFormat/Dwarf.h"
21#include "llvm/BinaryFormat/ELF.h"
22#include "llvm/BinaryFormat/GOFF.h"
23#include "llvm/BinaryFormat/MachO.h"
24#include "llvm/BinaryFormat/Wasm.h"
25#include "llvm/CodeGen/BasicBlockSectionUtils.h"
26#include "llvm/CodeGen/MachineBasicBlock.h"
27#include "llvm/CodeGen/MachineFunction.h"
28#include "llvm/CodeGen/MachineJumpTableInfo.h"
29#include "llvm/CodeGen/MachineModuleInfo.h"
30#include "llvm/CodeGen/MachineModuleInfoImpls.h"
31#include "llvm/IR/Comdat.h"
32#include "llvm/IR/Constants.h"
33#include "llvm/IR/DataLayout.h"
34#include "llvm/IR/DerivedTypes.h"
35#include "llvm/IR/DiagnosticInfo.h"
36#include "llvm/IR/DiagnosticPrinter.h"
37#include "llvm/IR/Function.h"
38#include "llvm/IR/GlobalAlias.h"
39#include "llvm/IR/GlobalObject.h"
40#include "llvm/IR/GlobalValue.h"
41#include "llvm/IR/GlobalVariable.h"
42#include "llvm/IR/Mangler.h"
43#include "llvm/IR/Metadata.h"
44#include "llvm/IR/Module.h"
45#include "llvm/IR/Type.h"
46#include "llvm/MC/MCAsmInfo.h"
47#include "llvm/MC/MCAsmInfoDarwin.h"
48#include "llvm/MC/MCContext.h"
49#include "llvm/MC/MCExpr.h"
50#include "llvm/MC/MCGOFFAttributes.h"
51#include "llvm/MC/MCSectionCOFF.h"
52#include "llvm/MC/MCSectionELF.h"
53#include "llvm/MC/MCSectionGOFF.h"
54#include "llvm/MC/MCSectionMachO.h"
55#include "llvm/MC/MCSectionWasm.h"
56#include "llvm/MC/MCSectionXCOFF.h"
57#include "llvm/MC/MCStreamer.h"
58#include "llvm/MC/MCSymbol.h"
59#include "llvm/MC/MCSymbolELF.h"
60#include "llvm/MC/MCSymbolGOFF.h"
61#include "llvm/MC/MCValue.h"
62#include "llvm/MC/SectionKind.h"
63#include "llvm/ProfileData/InstrProf.h"
64#include "llvm/Support/Base64.h"
65#include "llvm/Support/Casting.h"
66#include "llvm/Support/CodeGen.h"
67#include "llvm/Support/ErrorHandling.h"
68#include "llvm/Support/Format.h"
69#include "llvm/Support/Path.h"
70#include "llvm/Support/raw_ostream.h"
71#include "llvm/Target/TargetMachine.h"
72#include "llvm/TargetParser/Triple.h"
73#include <cassert>
74#include <string>
75
76using namespace llvm;
77using namespace dwarf;
78
79static cl::opt<bool> JumpTableInFunctionSection(
80 "jumptable-in-function-section", cl::Hidden, cl::init(Val: false),
81 cl::desc("Putting Jump Table in function section"));
82
83static void GetObjCImageInfo(Module &M, unsigned &Version, unsigned &Flags,
84 StringRef &Section) {
85 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
86 M.getModuleFlagsMetadata(Flags&: ModuleFlags);
87
88 for (const auto &MFE: ModuleFlags) {
89 // Ignore flags with 'Require' behaviour.
90 if (MFE.Behavior == Module::Require)
91 continue;
92
93 StringRef Key = MFE.Key->getString();
94 if (Key == "Objective-C Image Info Version") {
95 Version = mdconst::extract<ConstantInt>(MD: MFE.Val)->getZExtValue();
96 } else if (Key == "Objective-C Garbage Collection" ||
97 Key == "Objective-C GC Only" ||
98 Key == "Objective-C Is Simulated" ||
99 Key == "Objective-C Class Properties" ||
100 Key == "Objective-C Image Swift Version") {
101 Flags |= mdconst::extract<ConstantInt>(MD: MFE.Val)->getZExtValue();
102 } else if (Key == "Objective-C Image Info Section") {
103 Section = cast<MDString>(Val: MFE.Val)->getString();
104 }
105 // Backend generates L_OBJC_IMAGE_INFO from Swift ABI version + major + minor +
106 // "Objective-C Garbage Collection".
107 else if (Key == "Swift ABI Version") {
108 Flags |= (mdconst::extract<ConstantInt>(MD: MFE.Val)->getZExtValue()) << 8;
109 } else if (Key == "Swift Major Version") {
110 Flags |= (mdconst::extract<ConstantInt>(MD: MFE.Val)->getZExtValue()) << 24;
111 } else if (Key == "Swift Minor Version") {
112 Flags |= (mdconst::extract<ConstantInt>(MD: MFE.Val)->getZExtValue()) << 16;
113 }
114 }
115}
116
117//===----------------------------------------------------------------------===//
118// ELF
119//===----------------------------------------------------------------------===//
120
121void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
122 const TargetMachine &TgtM) {
123 TargetLoweringObjectFile::Initialize(ctx&: Ctx, TM: TgtM);
124
125 CodeModel::Model CM = TgtM.getCodeModel();
126 InitializeELF(UseInitArray_: TgtM.Options.UseInitArray);
127
128 switch (TgtM.getTargetTriple().getArch()) {
129 case Triple::arm:
130 case Triple::armeb:
131 case Triple::thumb:
132 case Triple::thumbeb:
133 if (Ctx.getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
134 break;
135 // Fallthrough if not using EHABI
136 [[fallthrough]];
137 case Triple::ppc:
138 case Triple::ppcle:
139 case Triple::x86:
140 PersonalityEncoding = isPositionIndependent()
141 ? dwarf::DW_EH_PE_indirect |
142 dwarf::DW_EH_PE_pcrel |
143 dwarf::DW_EH_PE_sdata4
144 : dwarf::DW_EH_PE_absptr;
145 LSDAEncoding = isPositionIndependent()
146 ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
147 : dwarf::DW_EH_PE_absptr;
148 TTypeEncoding = isPositionIndependent()
149 ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
150 dwarf::DW_EH_PE_sdata4
151 : dwarf::DW_EH_PE_absptr;
152 break;
153 case Triple::x86_64:
154 if (isPositionIndependent()) {
155 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
156 ((CM == CodeModel::Small || CM == CodeModel::Medium)
157 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
158 LSDAEncoding = dwarf::DW_EH_PE_pcrel |
159 (CM == CodeModel::Small
160 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
161 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
162 ((CM == CodeModel::Small || CM == CodeModel::Medium)
163 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
164 } else {
165 PersonalityEncoding =
166 (CM == CodeModel::Small || CM == CodeModel::Medium)
167 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
168 LSDAEncoding = (CM == CodeModel::Small)
169 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
170 TTypeEncoding = (CM == CodeModel::Small)
171 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
172 }
173 break;
174 case Triple::hexagon:
175 PersonalityEncoding = dwarf::DW_EH_PE_absptr;
176 LSDAEncoding = dwarf::DW_EH_PE_absptr;
177 TTypeEncoding = dwarf::DW_EH_PE_absptr;
178 if (isPositionIndependent()) {
179 PersonalityEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel;
180 LSDAEncoding |= dwarf::DW_EH_PE_pcrel;
181 TTypeEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel;
182 }
183 break;
184 case Triple::aarch64:
185 case Triple::aarch64_be:
186 case Triple::aarch64_32:
187 // The small model guarantees static code/data size < 4GB, but not where it
188 // will be in memory. Most of these could end up >2GB away so even a signed
189 // pc-relative 32-bit address is insufficient, theoretically.
190 //
191 // Use DW_EH_PE_indirect even for -fno-pic to avoid copy relocations.
192 LSDAEncoding = dwarf::DW_EH_PE_pcrel |
193 (TgtM.getTargetTriple().getEnvironment() == Triple::GNUILP32
194 ? dwarf::DW_EH_PE_sdata4
195 : dwarf::DW_EH_PE_sdata8);
196 PersonalityEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect;
197 TTypeEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect;
198 break;
199 case Triple::lanai:
200 LSDAEncoding = dwarf::DW_EH_PE_absptr;
201 PersonalityEncoding = dwarf::DW_EH_PE_absptr;
202 TTypeEncoding = dwarf::DW_EH_PE_absptr;
203 break;
204 case Triple::mips:
205 case Triple::mipsel:
206 case Triple::mips64:
207 case Triple::mips64el:
208 // MIPS uses indirect pointer to refer personality functions and types, so
209 // that the eh_frame section can be read-only. DW.ref.personality will be
210 // generated for relocation.
211 PersonalityEncoding = dwarf::DW_EH_PE_indirect;
212 // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
213 // identify N64 from just a triple.
214 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
215 dwarf::DW_EH_PE_sdata4;
216
217 // FreeBSD must be explicit about the data size and using pcrel since it's
218 // assembler/linker won't do the automatic conversion that the Linux tools
219 // do.
220 if (isPositionIndependent() || TgtM.getTargetTriple().isOSFreeBSD()) {
221 PersonalityEncoding |= dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
222 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
223 }
224 break;
225 case Triple::ppc64:
226 case Triple::ppc64le:
227 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
228 dwarf::DW_EH_PE_udata8;
229 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
230 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
231 dwarf::DW_EH_PE_udata8;
232 break;
233 case Triple::sparcel:
234 case Triple::sparc:
235 if (isPositionIndependent()) {
236 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
237 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
238 dwarf::DW_EH_PE_sdata4;
239 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
240 dwarf::DW_EH_PE_sdata4;
241 } else {
242 LSDAEncoding = dwarf::DW_EH_PE_absptr;
243 PersonalityEncoding = dwarf::DW_EH_PE_absptr;
244 TTypeEncoding = dwarf::DW_EH_PE_absptr;
245 }
246 CallSiteEncoding = dwarf::DW_EH_PE_udata4;
247 break;
248 case Triple::riscv32:
249 case Triple::riscv64:
250 case Triple::riscv32be:
251 case Triple::riscv64be:
252 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
253 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
254 dwarf::DW_EH_PE_sdata4;
255 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
256 dwarf::DW_EH_PE_sdata4;
257 CallSiteEncoding = dwarf::DW_EH_PE_udata4;
258 break;
259 case Triple::sparcv9:
260 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
261 if (isPositionIndependent()) {
262 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
263 dwarf::DW_EH_PE_sdata4;
264 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
265 dwarf::DW_EH_PE_sdata4;
266 } else {
267 PersonalityEncoding = dwarf::DW_EH_PE_absptr;
268 TTypeEncoding = dwarf::DW_EH_PE_absptr;
269 }
270 break;
271 case Triple::systemz:
272 // All currently-defined code models guarantee that 4-byte PC-relative
273 // values will be in range.
274 if (isPositionIndependent()) {
275 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
276 dwarf::DW_EH_PE_sdata4;
277 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
278 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
279 dwarf::DW_EH_PE_sdata4;
280 } else {
281 PersonalityEncoding = dwarf::DW_EH_PE_absptr;
282 LSDAEncoding = dwarf::DW_EH_PE_absptr;
283 TTypeEncoding = dwarf::DW_EH_PE_absptr;
284 }
285 break;
286 case Triple::loongarch32:
287 case Triple::loongarch64:
288 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
289 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
290 dwarf::DW_EH_PE_sdata4;
291 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
292 dwarf::DW_EH_PE_sdata4;
293 break;
294 default:
295 break;
296 }
297}
298
299void TargetLoweringObjectFileELF::getModuleMetadata(Module &M) {
300 SmallVector<GlobalValue *, 4> Vec;
301 collectUsedGlobalVariables(M, Vec, CompilerUsed: false);
302 for (GlobalValue *GV : Vec)
303 if (auto *GO = dyn_cast<GlobalObject>(Val: GV))
304 Used.insert(Ptr: GO);
305}
306
307void TargetLoweringObjectFileELF::emitModuleMetadata(MCStreamer &Streamer,
308 Module &M) const {
309 auto &C = getContext();
310
311 emitLinkerDirectives(Streamer, M);
312
313 if (NamedMDNode *DependentLibraries = M.getNamedMetadata(Name: "llvm.dependent-libraries")) {
314 auto *S = C.getELFSection(Section: ".deplibs", Type: ELF::SHT_LLVM_DEPENDENT_LIBRARIES,
315 Flags: ELF::SHF_MERGE | ELF::SHF_STRINGS, EntrySize: 1);
316
317 Streamer.switchSection(Section: S);
318
319 for (const auto *Operand : DependentLibraries->operands()) {
320 Streamer.emitBytes(
321 Data: cast<MDString>(Val: cast<MDNode>(Val: Operand)->getOperand(I: 0))->getString());
322 Streamer.emitInt8(Value: 0);
323 }
324 }
325
326 emitPseudoProbeDescMetadata(Streamer, M);
327
328 if (NamedMDNode *LLVMStats = M.getNamedMetadata(Name: "llvm.stats")) {
329 // Emit the metadata for llvm statistics into .llvm_stats section, which is
330 // formatted as a list of key/value pair, the value is base64 encoded.
331 auto *S = C.getObjectFileInfo()->getLLVMStatsSection();
332 Streamer.switchSection(Section: S);
333 for (const auto *Operand : LLVMStats->operands()) {
334 const auto *MD = cast<MDNode>(Val: Operand);
335 assert(MD->getNumOperands() % 2 == 0 &&
336 ("Operand num should be even for a list of key/value pair"));
337 for (size_t I = 0; I < MD->getNumOperands(); I += 2) {
338 // Encode the key string size.
339 auto *Key = cast<MDString>(Val: MD->getOperand(I));
340 Streamer.emitULEB128IntValue(Value: Key->getString().size());
341 Streamer.emitBytes(Data: Key->getString());
342 // Encode the value into a Base64 string.
343 std::string Value = encodeBase64(
344 Bytes: Twine(mdconst::dyn_extract<ConstantInt>(MD: MD->getOperand(I: I + 1))
345 ->getZExtValue())
346 .str());
347 Streamer.emitULEB128IntValue(Value: Value.size());
348 Streamer.emitBytes(Data: Value);
349 }
350 }
351 }
352
353 unsigned Version = 0;
354 unsigned Flags = 0;
355 StringRef Section;
356
357 GetObjCImageInfo(M, Version, Flags, Section);
358 if (!Section.empty()) {
359 auto *S = C.getELFSection(Section, Type: ELF::SHT_PROGBITS, Flags: ELF::SHF_ALLOC);
360 Streamer.switchSection(Section: S);
361 Streamer.emitLabel(Symbol: C.getOrCreateSymbol(Name: StringRef("OBJC_IMAGE_INFO")));
362 Streamer.emitInt32(Value: Version);
363 Streamer.emitInt32(Value: Flags);
364 Streamer.addBlankLine();
365 }
366
367 emitCGProfileMetadata(Streamer, M);
368}
369
370void TargetLoweringObjectFileELF::emitLinkerDirectives(MCStreamer &Streamer,
371 Module &M) const {
372 auto &C = getContext();
373 if (NamedMDNode *LinkerOptions = M.getNamedMetadata(Name: "llvm.linker.options")) {
374 auto *S = C.getELFSection(Section: ".linker-options", Type: ELF::SHT_LLVM_LINKER_OPTIONS,
375 Flags: ELF::SHF_EXCLUDE);
376
377 Streamer.switchSection(Section: S);
378
379 for (const auto *Operand : LinkerOptions->operands()) {
380 if (cast<MDNode>(Val: Operand)->getNumOperands() != 2)
381 report_fatal_error(reason: "invalid llvm.linker.options");
382 for (const auto &Option : cast<MDNode>(Val: Operand)->operands()) {
383 Streamer.emitBytes(Data: cast<MDString>(Val: Option)->getString());
384 Streamer.emitInt8(Value: 0);
385 }
386 }
387 }
388}
389
390MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol(
391 const GlobalValue *GV, const TargetMachine &TM,
392 MachineModuleInfo *MMI) const {
393 unsigned Encoding = getPersonalityEncoding();
394 if ((Encoding & 0x80) == DW_EH_PE_indirect)
395 return getContext().getOrCreateSymbol(Name: StringRef("DW.ref.") +
396 TM.getSymbol(GV)->getName());
397 if ((Encoding & 0x70) == DW_EH_PE_absptr)
398 return TM.getSymbol(GV);
399 report_fatal_error(reason: "We do not support this DWARF encoding yet!");
400}
401
402void TargetLoweringObjectFileELF::emitPersonalityValue(
403 MCStreamer &Streamer, const DataLayout &DL, const MCSymbol *Sym,
404 const MachineModuleInfo *MMI) const {
405 SmallString<64> NameData("DW.ref.");
406 NameData += Sym->getName();
407 auto *Label =
408 static_cast<MCSymbolELF *>(getContext().getOrCreateSymbol(Name: NameData));
409 Streamer.emitSymbolAttribute(Symbol: Label, Attribute: MCSA_Hidden);
410 Streamer.emitSymbolAttribute(Symbol: Label, Attribute: MCSA_Weak);
411 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
412 MCSection *Sec = getContext().getELFNamedSection(Prefix: ".data", Suffix: Label->getName(),
413 Type: ELF::SHT_PROGBITS, Flags, EntrySize: 0);
414 unsigned Size = DL.getPointerSize();
415 Streamer.switchSection(Section: Sec);
416 Streamer.emitValueToAlignment(Alignment: DL.getPointerABIAlignment(AS: 0));
417 Streamer.emitSymbolAttribute(Symbol: Label, Attribute: MCSA_ELF_TypeObject);
418 const MCExpr *E = MCConstantExpr::create(Value: Size, Ctx&: getContext());
419 Streamer.emitELFSize(Symbol: Label, Value: E);
420 Streamer.emitLabel(Symbol: Label);
421
422 emitPersonalityValueImpl(Streamer, DL, Sym, MMI);
423}
424
425void TargetLoweringObjectFileELF::emitPersonalityValueImpl(
426 MCStreamer &Streamer, const DataLayout &DL, const MCSymbol *Sym,
427 const MachineModuleInfo *MMI) const {
428 Streamer.emitSymbolValue(Sym, Size: DL.getPointerSize());
429}
430
431const MCExpr *TargetLoweringObjectFileELF::getTTypeGlobalReference(
432 const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
433 MachineModuleInfo *MMI, MCStreamer &Streamer) const {
434 if (Encoding & DW_EH_PE_indirect) {
435 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
436
437 MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, Suffix: ".DW.stub", TM);
438
439 // Add information about the stub reference to ELFMMI so that the stub
440 // gets emitted by the asmprinter.
441 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(Sym: SSym);
442 if (!StubSym.getPointer()) {
443 MCSymbol *Sym = TM.getSymbol(GV);
444 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
445 }
446
447 return TargetLoweringObjectFile::
448 getTTypeReference(Sym: MCSymbolRefExpr::create(Symbol: SSym, Ctx&: getContext()),
449 Encoding: Encoding & ~DW_EH_PE_indirect, Streamer);
450 }
451
452 return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, TM,
453 MMI, Streamer);
454}
455
456static SectionKind getELFKindForNamedSection(StringRef Name, SectionKind K) {
457 // N.B.: The defaults used in here are not the same ones used in MC.
458 // We follow gcc, MC follows gas. For example, given ".section .eh_frame",
459 // both gas and MC will produce a section with no flags. Given
460 // section(".eh_frame") gcc will produce:
461 //
462 // .section .eh_frame,"a",@progbits
463
464 if (Name == getInstrProfSectionName(IPSK: IPSK_covmap, OF: Triple::ELF,
465 /*AddSegmentInfo=*/false) ||
466 Name == getInstrProfSectionName(IPSK: IPSK_covfun, OF: Triple::ELF,
467 /*AddSegmentInfo=*/false) ||
468 Name == getInstrProfSectionName(IPSK: IPSK_covdata, OF: Triple::ELF,
469 /*AddSegmentInfo=*/false) ||
470 Name == getInstrProfSectionName(IPSK: IPSK_covname, OF: Triple::ELF,
471 /*AddSegmentInfo=*/false) ||
472 Name == ".llvmbc" || Name == ".llvmcmd")
473 return SectionKind::getMetadata();
474
475 if (!Name.starts_with(Prefix: ".")) return K;
476
477 // Default implementation based on some magic section names.
478 if (Name == ".bss" || Name.starts_with(Prefix: ".bss.") ||
479 Name.starts_with(Prefix: ".gnu.linkonce.b.") ||
480 Name.starts_with(Prefix: ".llvm.linkonce.b.") || Name == ".sbss" ||
481 Name.starts_with(Prefix: ".sbss.") || Name.starts_with(Prefix: ".gnu.linkonce.sb.") ||
482 Name.starts_with(Prefix: ".llvm.linkonce.sb."))
483 return SectionKind::getBSS();
484
485 if (Name == ".tdata" || Name.starts_with(Prefix: ".tdata.") ||
486 Name.starts_with(Prefix: ".gnu.linkonce.td.") ||
487 Name.starts_with(Prefix: ".llvm.linkonce.td."))
488 return SectionKind::getThreadData();
489
490 if (Name == ".tbss" || Name.starts_with(Prefix: ".tbss.") ||
491 Name.starts_with(Prefix: ".gnu.linkonce.tb.") ||
492 Name.starts_with(Prefix: ".llvm.linkonce.tb."))
493 return SectionKind::getThreadBSS();
494
495 return K;
496}
497
498static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
499 return SectionName.consume_front(Prefix) &&
500 (SectionName.empty() || SectionName[0] == '.');
501}
502
503static unsigned getELFSectionType(StringRef Name, SectionKind K) {
504 // Use SHT_NOTE for section whose name starts with ".note" to allow
505 // emitting ELF notes from C variable declaration.
506 // See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77609
507 if (Name.starts_with(Prefix: ".note"))
508 return ELF::SHT_NOTE;
509
510 if (hasPrefix(SectionName: Name, Prefix: ".init_array"))
511 return ELF::SHT_INIT_ARRAY;
512
513 if (hasPrefix(SectionName: Name, Prefix: ".fini_array"))
514 return ELF::SHT_FINI_ARRAY;
515
516 if (hasPrefix(SectionName: Name, Prefix: ".preinit_array"))
517 return ELF::SHT_PREINIT_ARRAY;
518
519 if (hasPrefix(SectionName: Name, Prefix: ".llvm.offloading"))
520 return ELF::SHT_LLVM_OFFLOADING;
521 if (Name == ".llvm.lto")
522 return ELF::SHT_LLVM_LTO;
523
524 if (K.isBSS() || K.isThreadBSS())
525 return ELF::SHT_NOBITS;
526
527 return ELF::SHT_PROGBITS;
528}
529
530static unsigned getELFSectionFlags(SectionKind K, const Triple &T) {
531 unsigned Flags = 0;
532
533 if (!K.isMetadata() && !K.isExclude())
534 Flags |= ELF::SHF_ALLOC;
535
536 if (K.isExclude())
537 Flags |= ELF::SHF_EXCLUDE;
538
539 if (K.isText())
540 Flags |= ELF::SHF_EXECINSTR;
541
542 if (K.isExecuteOnly()) {
543 if (T.isAArch64())
544 Flags |= ELF::SHF_AARCH64_PURECODE;
545 else if (T.isARM() || T.isThumb())
546 Flags |= ELF::SHF_ARM_PURECODE;
547 }
548
549 if (K.isWriteable())
550 Flags |= ELF::SHF_WRITE;
551
552 if (K.isThreadLocal())
553 Flags |= ELF::SHF_TLS;
554
555 if (K.isMergeableCString() || K.isMergeableConst())
556 Flags |= ELF::SHF_MERGE;
557
558 if (K.isMergeableCString())
559 Flags |= ELF::SHF_STRINGS;
560
561 return Flags;
562}
563
564static const Comdat *getELFComdat(const GlobalValue *GV) {
565 const Comdat *C = GV->getComdat();
566 if (!C)
567 return nullptr;
568
569 if (C->getSelectionKind() != Comdat::Any &&
570 C->getSelectionKind() != Comdat::NoDeduplicate)
571 report_fatal_error(reason: "ELF COMDATs only support SelectionKind::Any and "
572 "SelectionKind::NoDeduplicate, '" +
573 C->getName() + "' cannot be lowered.");
574
575 return C;
576}
577
578static const MCSymbolELF *getLinkedToSymbol(const GlobalObject *GO,
579 const TargetMachine &TM) {
580 MDNode *MD = GO->getMetadata(KindID: LLVMContext::MD_associated);
581 if (!MD)
582 return nullptr;
583
584 auto *VM = cast<ValueAsMetadata>(Val: MD->getOperand(I: 0).get());
585 auto *OtherGV = dyn_cast<GlobalValue>(Val: VM->getValue());
586 return OtherGV ? static_cast<const MCSymbolELF *>(TM.getSymbol(GV: OtherGV))
587 : nullptr;
588}
589
590static unsigned getEntrySizeForKind(SectionKind Kind) {
591 if (Kind.isMergeable1ByteCString())
592 return 1;
593 else if (Kind.isMergeable2ByteCString())
594 return 2;
595 else if (Kind.isMergeable4ByteCString())
596 return 4;
597 else if (Kind.isMergeableConst4())
598 return 4;
599 else if (Kind.isMergeableConst8())
600 return 8;
601 else if (Kind.isMergeableConst16())
602 return 16;
603 else if (Kind.isMergeableConst32())
604 return 32;
605 else {
606 // We shouldn't have mergeable C strings or mergeable constants that we
607 // didn't handle above.
608 assert(!Kind.isMergeableCString() && "unknown string width");
609 assert(!Kind.isMergeableConst() && "unknown data width");
610 return 0;
611 }
612}
613
614/// Return the section prefix name used by options FunctionsSections and
615/// DataSections.
616static StringRef getSectionPrefixForGlobal(SectionKind Kind, bool IsLarge) {
617 if (Kind.isText())
618 return IsLarge ? ".ltext" : ".text";
619 if (Kind.isReadOnly())
620 return IsLarge ? ".lrodata" : ".rodata";
621 if (Kind.isBSS())
622 return IsLarge ? ".lbss" : ".bss";
623 if (Kind.isThreadData())
624 return ".tdata";
625 if (Kind.isThreadBSS())
626 return ".tbss";
627 if (Kind.isData())
628 return IsLarge ? ".ldata" : ".data";
629 if (Kind.isReadOnlyWithRel())
630 return IsLarge ? ".ldata.rel.ro" : ".data.rel.ro";
631 llvm_unreachable("Unknown section kind");
632}
633
634static SmallString<128>
635getELFSectionNameForGlobal(const GlobalObject *GO, SectionKind Kind,
636 Mangler &Mang, const TargetMachine &TM,
637 unsigned EntrySize, bool UniqueSectionName,
638 const MachineJumpTableEntry *JTE) {
639 SmallString<128> Name =
640 getSectionPrefixForGlobal(Kind, IsLarge: TM.isLargeGlobalValue(GV: GO));
641 if (Kind.isMergeableCString()) {
642 // We also need alignment here.
643 // FIXME: this is getting the alignment of the character, not the
644 // alignment of the global!
645 Align Alignment = GO->getDataLayout().getPreferredAlign(
646 GV: cast<GlobalVariable>(Val: GO));
647
648 Name += ".str";
649 Name += utostr(X: EntrySize);
650 Name += ".";
651 Name += utostr(X: Alignment.value());
652 } else if (Kind.isMergeableConst()) {
653 Name += ".cst";
654 Name += utostr(X: EntrySize);
655 }
656
657 bool HasPrefix = false;
658 if (const auto *F = dyn_cast<Function>(Val: GO)) {
659 // Jump table hotness takes precedence over its enclosing function's hotness
660 // if it's known. The function's section prefix is used if jump table entry
661 // hotness is unknown.
662 if (JTE && JTE->Hotness != MachineFunctionDataHotness::Unknown) {
663 if (JTE->Hotness == MachineFunctionDataHotness::Hot) {
664 raw_svector_ostream(Name) << ".hot";
665 } else {
666 assert(JTE->Hotness == MachineFunctionDataHotness::Cold &&
667 "Hotness must be cold");
668 raw_svector_ostream(Name) << ".unlikely";
669 }
670 HasPrefix = true;
671 } else if (std::optional<StringRef> Prefix = F->getSectionPrefix()) {
672 raw_svector_ostream(Name) << '.' << *Prefix;
673 HasPrefix = true;
674 }
675 } else if (const auto *GV = dyn_cast<GlobalVariable>(Val: GO)) {
676 if (std::optional<StringRef> Prefix = GV->getSectionPrefix()) {
677 raw_svector_ostream(Name) << '.' << *Prefix;
678 HasPrefix = true;
679 }
680 }
681
682 if (UniqueSectionName) {
683 Name.push_back(Elt: '.');
684 TM.getNameWithPrefix(Name, GV: GO, Mang, /*MayAlwaysUsePrivate*/true);
685 } else if (HasPrefix)
686 // For distinguishing between .text.${text-section-prefix}. (with trailing
687 // dot) and .text.${function-name}
688 Name.push_back(Elt: '.');
689 return Name;
690}
691
692namespace {
693class LoweringDiagnosticInfo : public DiagnosticInfo {
694 const Twine &Msg;
695
696public:
697 LoweringDiagnosticInfo(const Twine &DiagMsg LLVM_LIFETIME_BOUND,
698 DiagnosticSeverity Severity = DS_Error)
699 : DiagnosticInfo(DK_Lowering, Severity), Msg(DiagMsg) {}
700 void print(DiagnosticPrinter &DP) const override { DP << Msg; }
701};
702}
703
704/// Calculate an appropriate unique ID for a section, and update Flags,
705/// EntrySize and NextUniqueID where appropriate.
706static unsigned
707calcUniqueIDUpdateFlagsAndSize(const GlobalObject *GO, StringRef SectionName,
708 SectionKind Kind, const TargetMachine &TM,
709 MCContext &Ctx, Mangler &Mang, unsigned &Flags,
710 unsigned &EntrySize, unsigned &NextUniqueID,
711 const bool Retain, const bool ForceUnique) {
712 // Increment uniqueID if we are forced to emit a unique section.
713 // This works perfectly fine with section attribute or pragma section as the
714 // sections with the same name are grouped together by the assembler.
715 if (ForceUnique)
716 return NextUniqueID++;
717
718 // A section can have at most one associated section. Put each global with
719 // MD_associated in a unique section.
720 const bool Associated = GO->getMetadata(KindID: LLVMContext::MD_associated);
721 if (Associated) {
722 Flags |= ELF::SHF_LINK_ORDER;
723 return NextUniqueID++;
724 }
725
726 if (Retain) {
727 if (TM.getTargetTriple().isOSSolaris())
728 Flags |= ELF::SHF_SUNW_NODISCARD;
729 else if (Ctx.getAsmInfo()->useIntegratedAssembler() ||
730 Ctx.getAsmInfo()->binutilsIsAtLeast(Major: 2, Minor: 36))
731 Flags |= ELF::SHF_GNU_RETAIN;
732 return NextUniqueID++;
733 }
734
735 // If two symbols with differing sizes end up in the same mergeable section
736 // that section can be assigned an incorrect entry size. To avoid this we
737 // usually put symbols of the same size into distinct mergeable sections with
738 // the same name. Doing so relies on the ",unique ," assembly feature. This
739 // feature is not available until binutils version 2.35
740 // (https://sourceware.org/bugzilla/show_bug.cgi?id=25380).
741 const bool SupportsUnique = Ctx.getAsmInfo()->useIntegratedAssembler() ||
742 Ctx.getAsmInfo()->binutilsIsAtLeast(Major: 2, Minor: 35);
743 if (!SupportsUnique) {
744 Flags &= ~ELF::SHF_MERGE;
745 EntrySize = 0;
746 return MCSection::NonUniqueID;
747 }
748
749 const bool SymbolMergeable = Flags & ELF::SHF_MERGE;
750 const bool SeenSectionNameBefore =
751 Ctx.isELFGenericMergeableSection(Name: SectionName);
752 // If this is the first occurrence of this section name, treat it as the
753 // generic section
754 if (!SymbolMergeable && !SeenSectionNameBefore) {
755 if (TM.getSeparateNamedSections())
756 return NextUniqueID++;
757 else
758 return MCSection::NonUniqueID;
759 }
760
761 // Symbols must be placed into sections with compatible entry sizes. Generate
762 // unique sections for symbols that have not been assigned to compatible
763 // sections.
764 const auto PreviousID =
765 Ctx.getELFUniqueIDForEntsize(SectionName, Flags, EntrySize);
766 if (PreviousID &&
767 (!TM.getSeparateNamedSections() || *PreviousID == MCSection::NonUniqueID))
768 return *PreviousID;
769
770 // If the user has specified the same section name as would be created
771 // implicitly for this symbol e.g. .rodata.str1.1, then we don't need
772 // to unique the section as the entry size for this symbol will be
773 // compatible with implicitly created sections.
774 SmallString<128> ImplicitSectionNameStem = getELFSectionNameForGlobal(
775 GO, Kind, Mang, TM, EntrySize, UniqueSectionName: false, /*MJTE=*/JTE: nullptr);
776 if (SymbolMergeable &&
777 Ctx.isELFImplicitMergeableSectionNamePrefix(Name: SectionName) &&
778 SectionName.starts_with(Prefix: ImplicitSectionNameStem))
779 return MCSection::NonUniqueID;
780
781 // We have seen this section name before, but with different flags or entity
782 // size. Create a new unique ID.
783 return NextUniqueID++;
784}
785
786static std::tuple<StringRef, bool, unsigned>
787getGlobalObjectInfo(const GlobalObject *GO, const TargetMachine &TM) {
788 StringRef Group = "";
789 bool IsComdat = false;
790 unsigned Flags = 0;
791 if (const Comdat *C = getELFComdat(GV: GO)) {
792 Flags |= ELF::SHF_GROUP;
793 Group = C->getName();
794 IsComdat = C->getSelectionKind() == Comdat::Any;
795 }
796 if (TM.isLargeGlobalValue(GV: GO))
797 Flags |= ELF::SHF_X86_64_LARGE;
798 return {Group, IsComdat, Flags};
799}
800
801static StringRef handlePragmaClangSection(const GlobalObject *GO,
802 SectionKind Kind) {
803 // Check if '#pragma clang section' name is applicable.
804 // Note that pragma directive overrides -ffunction-section, -fdata-section
805 // and so section name is exactly as user specified and not uniqued.
806 const GlobalVariable *GV = dyn_cast<GlobalVariable>(Val: GO);
807 if (GV && GV->hasImplicitSection()) {
808 auto Attrs = GV->getAttributes();
809 if (Attrs.hasAttribute(Kind: "bss-section") && Kind.isBSS())
810 return Attrs.getAttribute(Kind: "bss-section").getValueAsString();
811 else if (Attrs.hasAttribute(Kind: "rodata-section") && Kind.isReadOnly())
812 return Attrs.getAttribute(Kind: "rodata-section").getValueAsString();
813 else if (Attrs.hasAttribute(Kind: "relro-section") && Kind.isReadOnlyWithRel())
814 return Attrs.getAttribute(Kind: "relro-section").getValueAsString();
815 else if (Attrs.hasAttribute(Kind: "data-section") && Kind.isData())
816 return Attrs.getAttribute(Kind: "data-section").getValueAsString();
817 }
818
819 return GO->getSection();
820}
821
822static MCSection *selectExplicitSectionGlobal(const GlobalObject *GO,
823 SectionKind Kind,
824 const TargetMachine &TM,
825 MCContext &Ctx, Mangler &Mang,
826 unsigned &NextUniqueID,
827 bool Retain, bool ForceUnique) {
828 StringRef SectionName = handlePragmaClangSection(GO, Kind);
829
830 // Infer section flags from the section name if we can.
831 Kind = getELFKindForNamedSection(Name: SectionName, K: Kind);
832
833 unsigned Flags = getELFSectionFlags(K: Kind, T: TM.getTargetTriple());
834 auto [Group, IsComdat, ExtraFlags] = getGlobalObjectInfo(GO, TM);
835 Flags |= ExtraFlags;
836
837 unsigned EntrySize = getEntrySizeForKind(Kind);
838 const unsigned UniqueID = calcUniqueIDUpdateFlagsAndSize(
839 GO, SectionName, Kind, TM, Ctx, Mang, Flags, EntrySize, NextUniqueID,
840 Retain, ForceUnique);
841
842 const MCSymbolELF *LinkedToSym = getLinkedToSymbol(GO, TM);
843 MCSectionELF *Section = Ctx.getELFSection(
844 Section: SectionName, Type: getELFSectionType(Name: SectionName, K: Kind), Flags, EntrySize,
845 Group, IsComdat, UniqueID, LinkedToSym);
846 // Make sure that we did not get some other section with incompatible sh_link.
847 // This should not be possible due to UniqueID code above.
848 assert(Section->getLinkedToSymbol() == LinkedToSym &&
849 "Associated symbol mismatch between sections");
850
851 if (!(Ctx.getAsmInfo()->useIntegratedAssembler() ||
852 Ctx.getAsmInfo()->binutilsIsAtLeast(Major: 2, Minor: 35))) {
853 // If we are using GNU as before 2.35, then this symbol might have
854 // been placed in an incompatible mergeable section. Emit an error if this
855 // is the case to avoid creating broken output.
856 if ((Section->getFlags() & ELF::SHF_MERGE) &&
857 (Section->getEntrySize() != getEntrySizeForKind(Kind)))
858 GO->getContext().diagnose(DI: LoweringDiagnosticInfo(
859 "Symbol '" + GO->getName() + "' from module '" +
860 (GO->getParent() ? GO->getParent()->getSourceFileName() : "unknown") +
861 "' required a section with entry-size=" +
862 Twine(getEntrySizeForKind(Kind)) + " but was placed in section '" +
863 SectionName + "' with entry-size=" + Twine(Section->getEntrySize()) +
864 ": Explicit assignment by pragma or attribute of an incompatible "
865 "symbol to this section?"));
866 }
867
868 return Section;
869}
870
871MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
872 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
873 return selectExplicitSectionGlobal(GO, Kind, TM, Ctx&: getContext(), Mang&: getMangler(),
874 NextUniqueID, Retain: Used.count(Ptr: GO),
875 /* ForceUnique = */false);
876}
877
878static MCSectionELF *selectELFSectionForGlobal(
879 MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang,
880 const TargetMachine &TM, bool EmitUniqueSection, unsigned Flags,
881 unsigned *NextUniqueID, const MCSymbolELF *AssociatedSymbol,
882 const MachineJumpTableEntry *MJTE = nullptr) {
883
884 auto [Group, IsComdat, ExtraFlags] = getGlobalObjectInfo(GO, TM);
885 Flags |= ExtraFlags;
886
887 // Get the section entry size based on the kind.
888 unsigned EntrySize = getEntrySizeForKind(Kind);
889
890 bool UniqueSectionName = false;
891 unsigned UniqueID = MCSection::NonUniqueID;
892 if (EmitUniqueSection) {
893 if (TM.getUniqueSectionNames()) {
894 UniqueSectionName = true;
895 } else {
896 UniqueID = *NextUniqueID;
897 (*NextUniqueID)++;
898 }
899 }
900 SmallString<128> Name = getELFSectionNameForGlobal(
901 GO, Kind, Mang, TM, EntrySize, UniqueSectionName, JTE: MJTE);
902
903 // Use 0 as the unique ID for execute-only text.
904 if (Kind.isExecuteOnly())
905 UniqueID = 0;
906 return Ctx.getELFSection(Section: Name, Type: getELFSectionType(Name, K: Kind), Flags,
907 EntrySize, Group, IsComdat, UniqueID,
908 LinkedToSym: AssociatedSymbol);
909}
910
911static MCSection *selectELFSectionForGlobal(
912 MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang,
913 const TargetMachine &TM, bool Retain, bool EmitUniqueSection,
914 unsigned Flags, unsigned *NextUniqueID) {
915 const MCSymbolELF *LinkedToSym = getLinkedToSymbol(GO, TM);
916 if (LinkedToSym) {
917 EmitUniqueSection = true;
918 Flags |= ELF::SHF_LINK_ORDER;
919 }
920 if (Retain) {
921 if (TM.getTargetTriple().isOSSolaris()) {
922 EmitUniqueSection = true;
923 Flags |= ELF::SHF_SUNW_NODISCARD;
924 } else if (Ctx.getAsmInfo()->useIntegratedAssembler() ||
925 Ctx.getAsmInfo()->binutilsIsAtLeast(Major: 2, Minor: 36)) {
926 EmitUniqueSection = true;
927 Flags |= ELF::SHF_GNU_RETAIN;
928 }
929 }
930
931 MCSectionELF *Section = selectELFSectionForGlobal(
932 Ctx, GO, Kind, Mang, TM, EmitUniqueSection, Flags,
933 NextUniqueID, AssociatedSymbol: LinkedToSym);
934 assert(Section->getLinkedToSymbol() == LinkedToSym);
935 return Section;
936}
937
938MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
939 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
940 unsigned Flags = getELFSectionFlags(K: Kind, T: TM.getTargetTriple());
941
942 // If we have -ffunction-section or -fdata-section then we should emit the
943 // global value to a uniqued section specifically for it.
944 bool EmitUniqueSection = false;
945 if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
946 if (Kind.isText())
947 EmitUniqueSection = TM.getFunctionSections();
948 else
949 EmitUniqueSection = TM.getDataSections();
950 }
951 EmitUniqueSection |= GO->hasComdat();
952 return selectELFSectionForGlobal(Ctx&: getContext(), GO, Kind, Mang&: getMangler(), TM,
953 Retain: Used.count(Ptr: GO), EmitUniqueSection, Flags,
954 NextUniqueID: &NextUniqueID);
955}
956
957MCSection *TargetLoweringObjectFileELF::getUniqueSectionForFunction(
958 const Function &F, const TargetMachine &TM) const {
959 SectionKind Kind = SectionKind::getText();
960 unsigned Flags = getELFSectionFlags(K: Kind, T: TM.getTargetTriple());
961 // If the function's section names is pre-determined via pragma or a
962 // section attribute, call selectExplicitSectionGlobal.
963 if (F.hasSection())
964 return selectExplicitSectionGlobal(
965 GO: &F, Kind, TM, Ctx&: getContext(), Mang&: getMangler(), NextUniqueID,
966 Retain: Used.count(Ptr: &F), /* ForceUnique = */true);
967
968 return selectELFSectionForGlobal(
969 Ctx&: getContext(), GO: &F, Kind, Mang&: getMangler(), TM, Retain: Used.count(Ptr: &F),
970 /*EmitUniqueSection=*/true, Flags, NextUniqueID: &NextUniqueID);
971}
972
973MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
974 const Function &F, const TargetMachine &TM) const {
975 return getSectionForJumpTable(F, TM, /*JTE=*/nullptr);
976}
977
978MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
979 const Function &F, const TargetMachine &TM,
980 const MachineJumpTableEntry *JTE) const {
981 // If the function can be removed, produce a unique section so that
982 // the table doesn't prevent the removal.
983 const Comdat *C = F.getComdat();
984 bool EmitUniqueSection = TM.getFunctionSections() || C;
985 if (!EmitUniqueSection && !TM.getEnableStaticDataPartitioning())
986 return ReadOnlySection;
987
988 return selectELFSectionForGlobal(Ctx&: getContext(), GO: &F, Kind: SectionKind::getReadOnly(),
989 Mang&: getMangler(), TM, EmitUniqueSection,
990 Flags: ELF::SHF_ALLOC, NextUniqueID: &NextUniqueID,
991 /* AssociatedSymbol */ nullptr, MJTE: JTE);
992}
993
994MCSection *TargetLoweringObjectFileELF::getSectionForLSDA(
995 const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const {
996 // If neither COMDAT nor function sections, use the monolithic LSDA section.
997 // Re-use this path if LSDASection is null as in the Arm EHABI.
998 if (!LSDASection || (!F.hasComdat() && !TM.getFunctionSections()))
999 return LSDASection;
1000
1001 const auto *LSDA = static_cast<const MCSectionELF *>(LSDASection);
1002 unsigned Flags = LSDA->getFlags();
1003 const MCSymbolELF *LinkedToSym = nullptr;
1004 StringRef Group;
1005 bool IsComdat = false;
1006 if (const Comdat *C = getELFComdat(GV: &F)) {
1007 Flags |= ELF::SHF_GROUP;
1008 Group = C->getName();
1009 IsComdat = C->getSelectionKind() == Comdat::Any;
1010 }
1011 // Use SHF_LINK_ORDER to facilitate --gc-sections if we can use GNU ld>=2.36
1012 // or LLD, which support mixed SHF_LINK_ORDER & non-SHF_LINK_ORDER.
1013 if (TM.getFunctionSections() &&
1014 (getContext().getAsmInfo()->useIntegratedAssembler() &&
1015 getContext().getAsmInfo()->binutilsIsAtLeast(Major: 2, Minor: 36))) {
1016 Flags |= ELF::SHF_LINK_ORDER;
1017 LinkedToSym = static_cast<const MCSymbolELF *>(&FnSym);
1018 }
1019
1020 // Append the function name as the suffix like GCC, assuming
1021 // -funique-section-names applies to .gcc_except_table sections.
1022 return getContext().getELFSection(
1023 Section: (TM.getUniqueSectionNames() ? LSDA->getName() + "." + F.getName()
1024 : LSDA->getName()),
1025 Type: LSDA->getType(), Flags, EntrySize: 0, Group, IsComdat, UniqueID: MCSection::NonUniqueID,
1026 LinkedToSym);
1027}
1028
1029bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection(
1030 bool UsesLabelDifference, const Function &F) const {
1031 // We can always create relative relocations, so use another section
1032 // that can be marked non-executable.
1033 return false;
1034}
1035
1036/// Given a mergeable constant with the specified size and relocation
1037/// information, return a section that it should be placed in.
1038MCSection *TargetLoweringObjectFileELF::getSectionForConstant(
1039 const DataLayout &DL, SectionKind Kind, const Constant *C,
1040 Align &Alignment) const {
1041 if (Kind.isMergeableConst4() && MergeableConst4Section)
1042 return MergeableConst4Section;
1043 if (Kind.isMergeableConst8() && MergeableConst8Section)
1044 return MergeableConst8Section;
1045 if (Kind.isMergeableConst16() && MergeableConst16Section)
1046 return MergeableConst16Section;
1047 if (Kind.isMergeableConst32() && MergeableConst32Section)
1048 return MergeableConst32Section;
1049 if (Kind.isReadOnly())
1050 return ReadOnlySection;
1051
1052 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
1053 return DataRelROSection;
1054}
1055
1056MCSection *TargetLoweringObjectFileELF::getSectionForConstant(
1057 const DataLayout &DL, SectionKind Kind, const Constant *C, Align &Alignment,
1058 StringRef SectionSuffix) const {
1059 // TODO: Share code between this function and
1060 // MCObjectInfo::initELFMCObjectFileInfo.
1061 if (SectionSuffix.empty())
1062 return getSectionForConstant(DL, Kind, C, Alignment);
1063
1064 auto &Context = getContext();
1065 if (Kind.isMergeableConst4() && MergeableConst4Section)
1066 return Context.getELFSection(Section: ".rodata.cst4." + SectionSuffix + ".",
1067 Type: ELF::SHT_PROGBITS,
1068 Flags: ELF::SHF_ALLOC | ELF::SHF_MERGE, EntrySize: 4);
1069 if (Kind.isMergeableConst8() && MergeableConst8Section)
1070 return Context.getELFSection(Section: ".rodata.cst8." + SectionSuffix + ".",
1071 Type: ELF::SHT_PROGBITS,
1072 Flags: ELF::SHF_ALLOC | ELF::SHF_MERGE, EntrySize: 8);
1073 if (Kind.isMergeableConst16() && MergeableConst16Section)
1074 return Context.getELFSection(Section: ".rodata.cst16." + SectionSuffix + ".",
1075 Type: ELF::SHT_PROGBITS,
1076 Flags: ELF::SHF_ALLOC | ELF::SHF_MERGE, EntrySize: 16);
1077 if (Kind.isMergeableConst32() && MergeableConst32Section)
1078 return Context.getELFSection(Section: ".rodata.cst32." + SectionSuffix + ".",
1079 Type: ELF::SHT_PROGBITS,
1080 Flags: ELF::SHF_ALLOC | ELF::SHF_MERGE, EntrySize: 32);
1081 if (Kind.isReadOnly())
1082 return Context.getELFSection(Section: ".rodata." + SectionSuffix + ".",
1083 Type: ELF::SHT_PROGBITS, Flags: ELF::SHF_ALLOC);
1084
1085 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
1086 return Context.getELFSection(Section: ".data.rel.ro." + SectionSuffix + ".",
1087 Type: ELF::SHT_PROGBITS,
1088 Flags: ELF::SHF_ALLOC | ELF::SHF_WRITE);
1089}
1090
1091/// Returns a unique section for the given machine basic block.
1092MCSection *TargetLoweringObjectFileELF::getSectionForMachineBasicBlock(
1093 const Function &F, const MachineBasicBlock &MBB,
1094 const TargetMachine &TM) const {
1095 assert(MBB.isBeginSection() && "Basic block does not start a section!");
1096 unsigned UniqueID = MCSection::NonUniqueID;
1097
1098 // For cold sections use the .text.split. prefix along with the parent
1099 // function name. All cold blocks for the same function go to the same
1100 // section. Similarly all exception blocks are grouped by symbol name
1101 // under the .text.eh prefix. For regular sections, we either use a unique
1102 // name, or a unique ID for the section.
1103 SmallString<128> Name;
1104 StringRef FunctionSectionName = MBB.getParent()->getSection()->getName();
1105 if (FunctionSectionName == ".text" ||
1106 FunctionSectionName.starts_with(Prefix: ".text.")) {
1107 // Function is in a regular .text section.
1108 StringRef FunctionName = MBB.getParent()->getName();
1109 if (MBB.getSectionID() == MBBSectionID::ColdSectionID) {
1110 Name += BBSectionsColdTextPrefix;
1111 Name += FunctionName;
1112 } else if (MBB.getSectionID() == MBBSectionID::ExceptionSectionID) {
1113 Name += ".text.eh.";
1114 Name += FunctionName;
1115 } else {
1116 Name += FunctionSectionName;
1117 if (TM.getUniqueBasicBlockSectionNames()) {
1118 if (!Name.ends_with(Suffix: "."))
1119 Name += ".";
1120 Name += MBB.getSymbol()->getName();
1121 } else {
1122 UniqueID = NextUniqueID++;
1123 }
1124 }
1125 } else {
1126 // If the original function has a custom non-dot-text section, then emit
1127 // all basic block sections into that section too, each with a unique id.
1128 Name = FunctionSectionName;
1129 UniqueID = NextUniqueID++;
1130 }
1131
1132 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
1133 std::string GroupName;
1134 if (F.hasComdat()) {
1135 Flags |= ELF::SHF_GROUP;
1136 GroupName = F.getComdat()->getName().str();
1137 }
1138 return getContext().getELFSection(Section: Name, Type: ELF::SHT_PROGBITS, Flags,
1139 EntrySize: 0 /* Entry Size */, Group: GroupName,
1140 IsComdat: F.hasComdat(), UniqueID, LinkedToSym: nullptr);
1141}
1142
1143static MCSectionELF *getStaticStructorSection(MCContext &Ctx, bool UseInitArray,
1144 bool IsCtor, unsigned Priority,
1145 const MCSymbol *KeySym) {
1146 std::string Name;
1147 unsigned Type;
1148 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE;
1149 StringRef Comdat = KeySym ? KeySym->getName() : "";
1150
1151 if (KeySym)
1152 Flags |= ELF::SHF_GROUP;
1153
1154 if (UseInitArray) {
1155 if (IsCtor) {
1156 Type = ELF::SHT_INIT_ARRAY;
1157 Name = ".init_array";
1158 } else {
1159 Type = ELF::SHT_FINI_ARRAY;
1160 Name = ".fini_array";
1161 }
1162 if (Priority != 65535) {
1163 Name += '.';
1164 Name += utostr(X: Priority);
1165 }
1166 } else {
1167 // The default scheme is .ctor / .dtor, so we have to invert the priority
1168 // numbering.
1169 if (IsCtor)
1170 Name = ".ctors";
1171 else
1172 Name = ".dtors";
1173 if (Priority != 65535)
1174 raw_string_ostream(Name) << format(Fmt: ".%05u", Vals: 65535 - Priority);
1175 Type = ELF::SHT_PROGBITS;
1176 }
1177
1178 return Ctx.getELFSection(Section: Name, Type, Flags, EntrySize: 0, Group: Comdat, /*IsComdat=*/true);
1179}
1180
1181MCSection *TargetLoweringObjectFileELF::getStaticCtorSection(
1182 unsigned Priority, const MCSymbol *KeySym) const {
1183 return getStaticStructorSection(Ctx&: getContext(), UseInitArray, IsCtor: true, Priority,
1184 KeySym);
1185}
1186
1187MCSection *TargetLoweringObjectFileELF::getStaticDtorSection(
1188 unsigned Priority, const MCSymbol *KeySym) const {
1189 return getStaticStructorSection(Ctx&: getContext(), UseInitArray, IsCtor: false, Priority,
1190 KeySym);
1191}
1192
1193const MCExpr *TargetLoweringObjectFileELF::lowerSymbolDifference(
1194 const MCSymbol *LHS, const MCSymbol *RHS, int64_t Addend,
1195 std::optional<int64_t> PCRelativeOffset) const {
1196 auto &Ctx = getContext();
1197 const MCExpr *Res;
1198 // Return a relocatable expression with the PLT specifier, %plt(GV) or
1199 // %plt(GV-RHS).
1200 if (PCRelativeOffset && PLTPCRelativeSpecifier) {
1201 Res = MCSymbolRefExpr::create(Symbol: LHS, Ctx);
1202 // The current location is RHS plus *PCRelativeOffset. Compensate for it.
1203 Addend += *PCRelativeOffset;
1204 if (Addend)
1205 Res = MCBinaryExpr::createAdd(LHS: Res, RHS: MCConstantExpr::create(Value: Addend, Ctx),
1206 Ctx);
1207 return MCSpecifierExpr::create(Expr: Res, S: PLTPCRelativeSpecifier, Ctx&: getContext());
1208 }
1209
1210 if (!PLTRelativeSpecifier)
1211 return nullptr;
1212 Res = MCBinaryExpr::createSub(
1213 LHS: MCSymbolRefExpr::create(Symbol: LHS, specifier: PLTRelativeSpecifier, Ctx),
1214 RHS: MCSymbolRefExpr::create(Symbol: RHS, Ctx), Ctx);
1215 if (Addend)
1216 Res =
1217 MCBinaryExpr::createAdd(LHS: Res, RHS: MCConstantExpr::create(Value: Addend, Ctx), Ctx);
1218 return Res;
1219}
1220
1221// Reference the PLT entry of a function, optionally with a subtrahend (`RHS`).
1222const MCExpr *TargetLoweringObjectFileELF::lowerDSOLocalEquivalent(
1223 const MCSymbol *LHS, const MCSymbol *RHS, int64_t Addend,
1224 std::optional<int64_t> PCRelativeOffset, const TargetMachine &TM) const {
1225 if (RHS)
1226 return lowerSymbolDifference(LHS, RHS, Addend, PCRelativeOffset);
1227
1228 // Only the legacy MCSymbolRefExpr::VariantKind approach is implemented.
1229 // Reference LHS@plt or LHS@plt - RHS.
1230 if (PLTRelativeSpecifier)
1231 return MCSymbolRefExpr::create(Symbol: LHS, specifier: PLTRelativeSpecifier, Ctx&: getContext());
1232 return nullptr;
1233}
1234
1235MCSection *TargetLoweringObjectFileELF::getSectionForCommandLines() const {
1236 // Use ".GCC.command.line" since this feature is to support clang's
1237 // -frecord-gcc-switches which in turn attempts to mimic GCC's switch of the
1238 // same name.
1239 return getContext().getELFSection(Section: ".GCC.command.line", Type: ELF::SHT_PROGBITS,
1240 Flags: ELF::SHF_MERGE | ELF::SHF_STRINGS, EntrySize: 1);
1241}
1242
1243void
1244TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) {
1245 UseInitArray = UseInitArray_;
1246 MCContext &Ctx = getContext();
1247 if (!UseInitArray) {
1248 StaticCtorSection = Ctx.getELFSection(Section: ".ctors", Type: ELF::SHT_PROGBITS,
1249 Flags: ELF::SHF_ALLOC | ELF::SHF_WRITE);
1250
1251 StaticDtorSection = Ctx.getELFSection(Section: ".dtors", Type: ELF::SHT_PROGBITS,
1252 Flags: ELF::SHF_ALLOC | ELF::SHF_WRITE);
1253 return;
1254 }
1255
1256 StaticCtorSection = Ctx.getELFSection(Section: ".init_array", Type: ELF::SHT_INIT_ARRAY,
1257 Flags: ELF::SHF_WRITE | ELF::SHF_ALLOC);
1258 StaticDtorSection = Ctx.getELFSection(Section: ".fini_array", Type: ELF::SHT_FINI_ARRAY,
1259 Flags: ELF::SHF_WRITE | ELF::SHF_ALLOC);
1260}
1261
1262//===----------------------------------------------------------------------===//
1263// MachO
1264//===----------------------------------------------------------------------===//
1265
1266TargetLoweringObjectFileMachO::TargetLoweringObjectFileMachO() {
1267 SupportIndirectSymViaGOTPCRel = true;
1268}
1269
1270void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
1271 const TargetMachine &TM) {
1272 TargetLoweringObjectFile::Initialize(ctx&: Ctx, TM);
1273 if (TM.getRelocationModel() == Reloc::Static) {
1274 StaticCtorSection = Ctx.getMachOSection(Segment: "__TEXT", Section: "__constructor", TypeAndAttributes: 0,
1275 K: SectionKind::getData());
1276 StaticDtorSection = Ctx.getMachOSection(Segment: "__TEXT", Section: "__destructor", TypeAndAttributes: 0,
1277 K: SectionKind::getData());
1278 } else {
1279 StaticCtorSection = Ctx.getMachOSection(Segment: "__DATA", Section: "__mod_init_func",
1280 TypeAndAttributes: MachO::S_MOD_INIT_FUNC_POINTERS,
1281 K: SectionKind::getData());
1282 StaticDtorSection = Ctx.getMachOSection(Segment: "__DATA", Section: "__mod_term_func",
1283 TypeAndAttributes: MachO::S_MOD_TERM_FUNC_POINTERS,
1284 K: SectionKind::getData());
1285 }
1286
1287 PersonalityEncoding =
1288 dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
1289 LSDAEncoding = dwarf::DW_EH_PE_pcrel;
1290 TTypeEncoding =
1291 dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
1292}
1293
1294MCSection *TargetLoweringObjectFileMachO::getStaticDtorSection(
1295 unsigned Priority, const MCSymbol *KeySym) const {
1296 return StaticDtorSection;
1297 // In userspace, we lower global destructors via atexit(), but kernel/kext
1298 // environments do not provide this function so we still need to support the
1299 // legacy way here.
1300 // See the -disable-atexit-based-global-dtor-lowering CodeGen flag for more
1301 // context.
1302}
1303
1304void TargetLoweringObjectFileMachO::emitModuleMetadata(MCStreamer &Streamer,
1305 Module &M) const {
1306 // Emit the linker options if present.
1307 emitLinkerDirectives(Streamer, M);
1308
1309 unsigned VersionVal = 0;
1310 unsigned ImageInfoFlags = 0;
1311 StringRef SectionVal;
1312
1313 GetObjCImageInfo(M, Version&: VersionVal, Flags&: ImageInfoFlags, Section&: SectionVal);
1314 emitCGProfileMetadata(Streamer, M);
1315
1316 // The section is mandatory. If we don't have it, then we don't have GC info.
1317 if (SectionVal.empty())
1318 return;
1319
1320 StringRef Segment, Section;
1321 unsigned TAA = 0, StubSize = 0;
1322 bool TAAParsed;
1323 if (Error E = MCSectionMachO::ParseSectionSpecifier(
1324 Spec: SectionVal, Segment, Section, TAA, TAAParsed, StubSize)) {
1325 // If invalid, report the error with report_fatal_error.
1326 report_fatal_error(reason: "Invalid section specifier '" + Section +
1327 "': " + toString(E: std::move(E)) + ".");
1328 }
1329
1330 // Get the section.
1331 MCSectionMachO *S = getContext().getMachOSection(
1332 Segment, Section, TypeAndAttributes: TAA, Reserved2: StubSize, K: SectionKind::getData());
1333 Streamer.switchSection(Section: S);
1334 Streamer.emitLabel(Symbol: getContext().
1335 getOrCreateSymbol(Name: StringRef("L_OBJC_IMAGE_INFO")));
1336 Streamer.emitInt32(Value: VersionVal);
1337 Streamer.emitInt32(Value: ImageInfoFlags);
1338 Streamer.addBlankLine();
1339}
1340
1341void TargetLoweringObjectFileMachO::emitLinkerDirectives(MCStreamer &Streamer,
1342 Module &M) const {
1343 if (auto *LinkerOptions = M.getNamedMetadata(Name: "llvm.linker.options")) {
1344 for (const auto *Option : LinkerOptions->operands()) {
1345 SmallVector<std::string, 4> StrOptions;
1346 for (const auto &Piece : cast<MDNode>(Val: Option)->operands())
1347 StrOptions.push_back(Elt: std::string(cast<MDString>(Val: Piece)->getString()));
1348 Streamer.emitLinkerOptions(Kind: StrOptions);
1349 }
1350 }
1351}
1352
1353static void checkMachOComdat(const GlobalValue *GV) {
1354 const Comdat *C = GV->getComdat();
1355 if (!C)
1356 return;
1357
1358 report_fatal_error(reason: "MachO doesn't support COMDATs, '" + C->getName() +
1359 "' cannot be lowered.");
1360}
1361
1362MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
1363 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
1364
1365 StringRef SectionName = handlePragmaClangSection(GO, Kind);
1366
1367 // Parse the section specifier and create it if valid.
1368 StringRef Segment, Section;
1369 unsigned TAA = 0, StubSize = 0;
1370 bool TAAParsed;
1371
1372 checkMachOComdat(GV: GO);
1373
1374 if (Error E = MCSectionMachO::ParseSectionSpecifier(
1375 Spec: SectionName, Segment, Section, TAA, TAAParsed, StubSize)) {
1376 // If invalid, report the error with report_fatal_error.
1377 report_fatal_error(reason: "Global variable '" + GO->getName() +
1378 "' has an invalid section specifier '" +
1379 GO->getSection() + "': " + toString(E: std::move(E)) + ".");
1380 }
1381
1382 // Get the section.
1383 MCSectionMachO *S =
1384 getContext().getMachOSection(Segment, Section, TypeAndAttributes: TAA, Reserved2: StubSize, K: Kind);
1385
1386 // If TAA wasn't set by ParseSectionSpecifier() above,
1387 // use the value returned by getMachOSection() as a default.
1388 if (!TAAParsed)
1389 TAA = S->getTypeAndAttributes();
1390
1391 // Okay, now that we got the section, verify that the TAA & StubSize agree.
1392 // If the user declared multiple globals with different section flags, we need
1393 // to reject it here.
1394 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
1395 // If invalid, report the error with report_fatal_error.
1396 report_fatal_error(reason: "Global variable '" + GO->getName() +
1397 "' section type or attributes does not match previous"
1398 " section specifier");
1399 }
1400
1401 return S;
1402}
1403
1404MCSection *TargetLoweringObjectFileMachO::SelectSectionForGlobal(
1405 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
1406 checkMachOComdat(GV: GO);
1407
1408 // Handle thread local data.
1409 if (Kind.isThreadBSS()) return TLSBSSSection;
1410 if (Kind.isThreadData()) return TLSDataSection;
1411
1412 if (Kind.isText())
1413 return GO->isWeakForLinker() ? TextCoalSection : TextSection;
1414
1415 // If this is weak/linkonce, put this in a coalescable section, either in text
1416 // or data depending on if it is writable.
1417 if (GO->isWeakForLinker()) {
1418 if (Kind.isReadOnly())
1419 return ConstTextCoalSection;
1420 if (Kind.isReadOnlyWithRel())
1421 return ConstDataCoalSection;
1422 return DataCoalSection;
1423 }
1424
1425 // FIXME: Alignment check should be handled by section classifier.
1426 if (Kind.isMergeable1ByteCString() &&
1427 GO->getDataLayout().getPreferredAlign(
1428 GV: cast<GlobalVariable>(Val: GO)) < Align(32))
1429 return CStringSection;
1430
1431 // Do not put 16-bit arrays in the UString section if they have an
1432 // externally visible label, this runs into issues with certain linker
1433 // versions.
1434 if (Kind.isMergeable2ByteCString() && !GO->hasExternalLinkage() &&
1435 GO->getDataLayout().getPreferredAlign(
1436 GV: cast<GlobalVariable>(Val: GO)) < Align(32))
1437 return UStringSection;
1438
1439 // With MachO only variables whose corresponding symbol starts with 'l' or
1440 // 'L' can be merged, so we only try merging GVs with private linkage.
1441 if (GO->hasPrivateLinkage() && Kind.isMergeableConst()) {
1442 if (Kind.isMergeableConst4())
1443 return FourByteConstantSection;
1444 if (Kind.isMergeableConst8())
1445 return EightByteConstantSection;
1446 if (Kind.isMergeableConst16())
1447 return SixteenByteConstantSection;
1448 }
1449
1450 // Otherwise, if it is readonly, but not something we can specially optimize,
1451 // just drop it in .const.
1452 if (Kind.isReadOnly())
1453 return ReadOnlySection;
1454
1455 // If this is marked const, put it into a const section. But if the dynamic
1456 // linker needs to write to it, put it in the data segment.
1457 if (Kind.isReadOnlyWithRel())
1458 return ConstDataSection;
1459
1460 // Put zero initialized globals with strong external linkage in the
1461 // DATA, __common section with the .zerofill directive.
1462 if (Kind.isBSSExtern())
1463 return DataCommonSection;
1464
1465 // Put zero initialized globals with local linkage in __DATA,__bss directive
1466 // with the .zerofill directive (aka .lcomm).
1467 if (Kind.isBSSLocal())
1468 return DataBSSSection;
1469
1470 // Otherwise, just drop the variable in the normal data section.
1471 return DataSection;
1472}
1473
1474MCSection *TargetLoweringObjectFileMachO::getSectionForConstant(
1475 const DataLayout &DL, SectionKind Kind, const Constant *C,
1476 Align &Alignment) const {
1477 // If this constant requires a relocation, we have to put it in the data
1478 // segment, not in the text segment.
1479 if (Kind.isData() || Kind.isReadOnlyWithRel())
1480 return ConstDataSection;
1481
1482 if (Kind.isMergeableConst4())
1483 return FourByteConstantSection;
1484 if (Kind.isMergeableConst8())
1485 return EightByteConstantSection;
1486 if (Kind.isMergeableConst16())
1487 return SixteenByteConstantSection;
1488 return ReadOnlySection; // .const
1489}
1490
1491MCSection *TargetLoweringObjectFileMachO::getSectionForCommandLines() const {
1492 return getContext().getMachOSection(Segment: "__TEXT", Section: "__command_line", TypeAndAttributes: 0,
1493 K: SectionKind::getReadOnly());
1494}
1495
1496const MCExpr *TargetLoweringObjectFileMachO::getTTypeGlobalReference(
1497 const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
1498 MachineModuleInfo *MMI, MCStreamer &Streamer) const {
1499 // The mach-o version of this method defaults to returning a stub reference.
1500
1501 if (Encoding & DW_EH_PE_indirect) {
1502 MachineModuleInfoMachO &MachOMMI =
1503 MMI->getObjFileInfo<MachineModuleInfoMachO>();
1504
1505 MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, Suffix: "$non_lazy_ptr", TM);
1506
1507 // Add information about the stub reference to MachOMMI so that the stub
1508 // gets emitted by the asmprinter.
1509 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Sym: SSym);
1510 if (!StubSym.getPointer()) {
1511 MCSymbol *Sym = TM.getSymbol(GV);
1512 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
1513 }
1514
1515 return TargetLoweringObjectFile::
1516 getTTypeReference(Sym: MCSymbolRefExpr::create(Symbol: SSym, Ctx&: getContext()),
1517 Encoding: Encoding & ~DW_EH_PE_indirect, Streamer);
1518 }
1519
1520 return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, TM,
1521 MMI, Streamer);
1522}
1523
1524MCSymbol *TargetLoweringObjectFileMachO::getCFIPersonalitySymbol(
1525 const GlobalValue *GV, const TargetMachine &TM,
1526 MachineModuleInfo *MMI) const {
1527 // The mach-o version of this method defaults to returning a stub reference.
1528 MachineModuleInfoMachO &MachOMMI =
1529 MMI->getObjFileInfo<MachineModuleInfoMachO>();
1530
1531 MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, Suffix: "$non_lazy_ptr", TM);
1532
1533 // Add information about the stub reference to MachOMMI so that the stub
1534 // gets emitted by the asmprinter.
1535 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Sym: SSym);
1536 if (!StubSym.getPointer()) {
1537 MCSymbol *Sym = TM.getSymbol(GV);
1538 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
1539 }
1540
1541 return SSym;
1542}
1543
1544const MCExpr *TargetLoweringObjectFileMachO::getIndirectSymViaGOTPCRel(
1545 const GlobalValue *GV, const MCSymbol *Sym, const MCValue &MV,
1546 int64_t Offset, MachineModuleInfo *MMI, MCStreamer &Streamer) const {
1547 // Although MachO 32-bit targets do not explicitly have a GOTPCREL relocation
1548 // as 64-bit do, we replace the GOT equivalent by accessing the final symbol
1549 // through a non_lazy_ptr stub instead. One advantage is that it allows the
1550 // computation of deltas to final external symbols. Example:
1551 //
1552 // _extgotequiv:
1553 // .long _extfoo
1554 //
1555 // _delta:
1556 // .long _extgotequiv-_delta
1557 //
1558 // is transformed to:
1559 //
1560 // _delta:
1561 // .long L_extfoo$non_lazy_ptr-(_delta+0)
1562 //
1563 // .section __IMPORT,__pointers,non_lazy_symbol_pointers
1564 // L_extfoo$non_lazy_ptr:
1565 // .indirect_symbol _extfoo
1566 // .long 0
1567 //
1568 // The indirect symbol table (and sections of non_lazy_symbol_pointers type)
1569 // may point to both local (same translation unit) and global (other
1570 // translation units) symbols. Example:
1571 //
1572 // .section __DATA,__pointers,non_lazy_symbol_pointers
1573 // L1:
1574 // .indirect_symbol _myGlobal
1575 // .long 0
1576 // L2:
1577 // .indirect_symbol _myLocal
1578 // .long _myLocal
1579 //
1580 // If the symbol is local, instead of the symbol's index, the assembler
1581 // places the constant INDIRECT_SYMBOL_LOCAL into the indirect symbol table.
1582 // Then the linker will notice the constant in the table and will look at the
1583 // content of the symbol.
1584 MachineModuleInfoMachO &MachOMMI =
1585 MMI->getObjFileInfo<MachineModuleInfoMachO>();
1586 MCContext &Ctx = getContext();
1587
1588 // The offset must consider the original displacement from the base symbol
1589 // since 32-bit targets don't have a GOTPCREL to fold the PC displacement.
1590 Offset = -MV.getConstant();
1591 const MCSymbol *BaseSym = MV.getSubSym();
1592
1593 // Access the final symbol via sym$non_lazy_ptr and generate the appropriated
1594 // non_lazy_ptr stubs.
1595 SmallString<128> Name;
1596 StringRef Suffix = "$non_lazy_ptr";
1597 Name += MMI->getModule()->getDataLayout().getPrivateGlobalPrefix();
1598 Name += Sym->getName();
1599 Name += Suffix;
1600 MCSymbol *Stub = Ctx.getOrCreateSymbol(Name);
1601
1602 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Sym: Stub);
1603
1604 if (!StubSym.getPointer())
1605 StubSym = MachineModuleInfoImpl::StubValueTy(const_cast<MCSymbol *>(Sym),
1606 !GV->hasLocalLinkage());
1607
1608 const MCExpr *BSymExpr = MCSymbolRefExpr::create(Symbol: BaseSym, Ctx);
1609 const MCExpr *LHS = MCSymbolRefExpr::create(Symbol: Stub, Ctx);
1610
1611 if (!Offset)
1612 return MCBinaryExpr::createSub(LHS, RHS: BSymExpr, Ctx);
1613
1614 const MCExpr *RHS =
1615 MCBinaryExpr::createAdd(LHS: BSymExpr, RHS: MCConstantExpr::create(Value: Offset, Ctx), Ctx);
1616 return MCBinaryExpr::createSub(LHS, RHS, Ctx);
1617}
1618
1619static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo,
1620 const MCSection &Section) {
1621 if (!MCAsmInfoDarwin::isSectionAtomizableBySymbols(Section))
1622 return true;
1623
1624 // FIXME: we should be able to use private labels for sections that can't be
1625 // dead-stripped (there's no issue with blocking atomization there), but `ld
1626 // -r` sometimes drops the no_dead_strip attribute from sections so for safety
1627 // we don't allow it.
1628 return false;
1629}
1630
1631void TargetLoweringObjectFileMachO::getNameWithPrefix(
1632 SmallVectorImpl<char> &OutName, const GlobalValue *GV,
1633 const TargetMachine &TM) const {
1634 bool CannotUsePrivateLabel = true;
1635 if (auto *GO = GV->getAliaseeObject()) {
1636 SectionKind GOKind = TargetLoweringObjectFile::getKindForGlobal(GO, TM);
1637 const MCSection *TheSection = SectionForGlobal(GO, Kind: GOKind, TM);
1638 CannotUsePrivateLabel =
1639 !canUsePrivateLabel(AsmInfo: *TM.getMCAsmInfo(), Section: *TheSection);
1640 }
1641 getMangler().getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
1642}
1643
1644//===----------------------------------------------------------------------===//
1645// COFF
1646//===----------------------------------------------------------------------===//
1647
1648static unsigned
1649getCOFFSectionFlags(SectionKind K, const TargetMachine &TM) {
1650 unsigned Flags = 0;
1651 bool isThumb = TM.getTargetTriple().getArch() == Triple::thumb;
1652
1653 if (K.isMetadata())
1654 Flags |=
1655 COFF::IMAGE_SCN_MEM_DISCARDABLE;
1656 else if (K.isExclude())
1657 Flags |=
1658 COFF::IMAGE_SCN_LNK_REMOVE | COFF::IMAGE_SCN_MEM_DISCARDABLE;
1659 else if (K.isText())
1660 Flags |=
1661 COFF::IMAGE_SCN_MEM_EXECUTE |
1662 COFF::IMAGE_SCN_MEM_READ |
1663 COFF::IMAGE_SCN_CNT_CODE |
1664 (isThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0);
1665 else if (K.isBSS())
1666 Flags |=
1667 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
1668 COFF::IMAGE_SCN_MEM_READ |
1669 COFF::IMAGE_SCN_MEM_WRITE;
1670 else if (K.isThreadLocal())
1671 Flags |=
1672 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1673 COFF::IMAGE_SCN_MEM_READ |
1674 COFF::IMAGE_SCN_MEM_WRITE;
1675 else if (K.isReadOnly() || K.isReadOnlyWithRel())
1676 Flags |=
1677 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1678 COFF::IMAGE_SCN_MEM_READ;
1679 else if (K.isWriteable())
1680 Flags |=
1681 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1682 COFF::IMAGE_SCN_MEM_READ |
1683 COFF::IMAGE_SCN_MEM_WRITE;
1684
1685 return Flags;
1686}
1687
1688static const GlobalValue *getComdatGVForCOFF(const GlobalValue *GV) {
1689 const Comdat *C = GV->getComdat();
1690 assert(C && "expected GV to have a Comdat!");
1691
1692 StringRef ComdatGVName = C->getName();
1693 const GlobalValue *ComdatGV = GV->getParent()->getNamedValue(Name: ComdatGVName);
1694 if (!ComdatGV)
1695 report_fatal_error(reason: "Associative COMDAT symbol '" + ComdatGVName +
1696 "' does not exist.");
1697
1698 if (ComdatGV->getComdat() != C)
1699 report_fatal_error(reason: "Associative COMDAT symbol '" + ComdatGVName +
1700 "' is not a key for its COMDAT.");
1701
1702 return ComdatGV;
1703}
1704
1705static int getSelectionForCOFF(const GlobalValue *GV) {
1706 if (const Comdat *C = GV->getComdat()) {
1707 const GlobalValue *ComdatKey = getComdatGVForCOFF(GV);
1708 if (const auto *GA = dyn_cast<GlobalAlias>(Val: ComdatKey))
1709 ComdatKey = GA->getAliaseeObject();
1710 if (ComdatKey == GV) {
1711 switch (C->getSelectionKind()) {
1712 case Comdat::Any:
1713 return COFF::IMAGE_COMDAT_SELECT_ANY;
1714 case Comdat::ExactMatch:
1715 return COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH;
1716 case Comdat::Largest:
1717 return COFF::IMAGE_COMDAT_SELECT_LARGEST;
1718 case Comdat::NoDeduplicate:
1719 return COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
1720 case Comdat::SameSize:
1721 return COFF::IMAGE_COMDAT_SELECT_SAME_SIZE;
1722 }
1723 } else {
1724 return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
1725 }
1726 }
1727 return 0;
1728}
1729
1730MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
1731 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
1732 StringRef Name = handlePragmaClangSection(GO, Kind);
1733 if (Name == getInstrProfSectionName(IPSK: IPSK_covmap, OF: Triple::COFF,
1734 /*AddSegmentInfo=*/false) ||
1735 Name == getInstrProfSectionName(IPSK: IPSK_covfun, OF: Triple::COFF,
1736 /*AddSegmentInfo=*/false) ||
1737 Name == getInstrProfSectionName(IPSK: IPSK_covdata, OF: Triple::COFF,
1738 /*AddSegmentInfo=*/false) ||
1739 Name == getInstrProfSectionName(IPSK: IPSK_covname, OF: Triple::COFF,
1740 /*AddSegmentInfo=*/false) ||
1741 Name == ".llvmbc" || Name == ".llvmcmd")
1742 Kind = SectionKind::getMetadata();
1743 int Selection = 0;
1744 unsigned Characteristics = getCOFFSectionFlags(K: Kind, TM);
1745 StringRef COMDATSymName = "";
1746 if (GO->hasComdat()) {
1747 Selection = getSelectionForCOFF(GV: GO);
1748 const GlobalValue *ComdatGV;
1749 if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
1750 ComdatGV = getComdatGVForCOFF(GV: GO);
1751 else
1752 ComdatGV = GO;
1753
1754 if (!ComdatGV->hasPrivateLinkage()) {
1755 MCSymbol *Sym = TM.getSymbol(GV: ComdatGV);
1756 COMDATSymName = Sym->getName();
1757 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1758 } else {
1759 Selection = 0;
1760 }
1761 }
1762
1763 return getContext().getCOFFSection(Section: Name, Characteristics, COMDATSymName,
1764 Selection);
1765}
1766
1767static StringRef getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
1768 if (Kind.isText())
1769 return ".text";
1770 if (Kind.isBSS())
1771 return ".bss";
1772 if (Kind.isThreadLocal())
1773 return ".tls$";
1774 if (Kind.isReadOnly() || Kind.isReadOnlyWithRel())
1775 return ".rdata";
1776 return ".data";
1777}
1778
1779MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
1780 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
1781 // If we have -ffunction-sections then we should emit the global value to a
1782 // uniqued section specifically for it.
1783 bool EmitUniquedSection;
1784 if (Kind.isText())
1785 EmitUniquedSection = TM.getFunctionSections();
1786 else
1787 EmitUniquedSection = TM.getDataSections();
1788
1789 if ((EmitUniquedSection && !Kind.isCommon()) || GO->hasComdat()) {
1790 SmallString<256> Name = getCOFFSectionNameForUniqueGlobal(Kind);
1791
1792 unsigned Characteristics = getCOFFSectionFlags(K: Kind, TM);
1793
1794 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1795 int Selection = getSelectionForCOFF(GV: GO);
1796 if (!Selection)
1797 Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
1798 const GlobalValue *ComdatGV;
1799 if (GO->hasComdat())
1800 ComdatGV = getComdatGVForCOFF(GV: GO);
1801 else
1802 ComdatGV = GO;
1803
1804 unsigned UniqueID = MCSection::NonUniqueID;
1805 if (EmitUniquedSection)
1806 UniqueID = NextUniqueID++;
1807
1808 if (!ComdatGV->hasPrivateLinkage()) {
1809 MCSymbol *Sym = TM.getSymbol(GV: ComdatGV);
1810 StringRef COMDATSymName = Sym->getName();
1811
1812 if (const auto *F = dyn_cast<Function>(Val: GO))
1813 if (std::optional<StringRef> Prefix = F->getSectionPrefix())
1814 raw_svector_ostream(Name) << '$' << *Prefix;
1815
1816 // Append "$symbol" to the section name *before* IR-level mangling is
1817 // applied when targetting mingw. This is what GCC does, and the ld.bfd
1818 // COFF linker will not properly handle comdats otherwise.
1819 if (getContext().getTargetTriple().isOSCygMing())
1820 raw_svector_ostream(Name) << '$' << ComdatGV->getName();
1821
1822 return getContext().getCOFFSection(Section: Name, Characteristics, COMDATSymName,
1823 Selection, UniqueID);
1824 } else {
1825 SmallString<256> TmpData;
1826 getMangler().getNameWithPrefix(OutName&: TmpData, GV: GO, /*CannotUsePrivateLabel=*/true);
1827 return getContext().getCOFFSection(Section: Name, Characteristics, COMDATSymName: TmpData,
1828 Selection, UniqueID);
1829 }
1830 }
1831
1832 if (Kind.isText())
1833 return TextSection;
1834
1835 if (Kind.isThreadLocal())
1836 return TLSDataSection;
1837
1838 if (Kind.isReadOnly() || Kind.isReadOnlyWithRel())
1839 return ReadOnlySection;
1840
1841 // Note: we claim that common symbols are put in BSSSection, but they are
1842 // really emitted with the magic .comm directive, which creates a symbol table
1843 // entry but not a section.
1844 if (Kind.isBSS() || Kind.isCommon())
1845 return BSSSection;
1846
1847 return DataSection;
1848}
1849
1850void TargetLoweringObjectFileCOFF::getNameWithPrefix(
1851 SmallVectorImpl<char> &OutName, const GlobalValue *GV,
1852 const TargetMachine &TM) const {
1853 bool CannotUsePrivateLabel = false;
1854 if (GV->hasPrivateLinkage() &&
1855 ((isa<Function>(Val: GV) && TM.getFunctionSections()) ||
1856 (isa<GlobalVariable>(Val: GV) && TM.getDataSections())))
1857 CannotUsePrivateLabel = true;
1858
1859 getMangler().getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
1860}
1861
1862MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
1863 const Function &F, const TargetMachine &TM) const {
1864 // If the function can be removed, produce a unique section so that
1865 // the table doesn't prevent the removal.
1866 const Comdat *C = F.getComdat();
1867 bool EmitUniqueSection = TM.getFunctionSections() || C;
1868 if (!EmitUniqueSection)
1869 return ReadOnlySection;
1870
1871 // FIXME: we should produce a symbol for F instead.
1872 if (F.hasPrivateLinkage())
1873 return ReadOnlySection;
1874
1875 MCSymbol *Sym = TM.getSymbol(GV: &F);
1876 StringRef COMDATSymName = Sym->getName();
1877
1878 SectionKind Kind = SectionKind::getReadOnly();
1879 StringRef SecName = getCOFFSectionNameForUniqueGlobal(Kind);
1880 unsigned Characteristics = getCOFFSectionFlags(K: Kind, TM);
1881 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1882 unsigned UniqueID = NextUniqueID++;
1883
1884 return getContext().getCOFFSection(Section: SecName, Characteristics, COMDATSymName,
1885 Selection: COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE,
1886 UniqueID);
1887}
1888
1889bool TargetLoweringObjectFileCOFF::shouldPutJumpTableInFunctionSection(
1890 bool UsesLabelDifference, const Function &F) const {
1891 if (TM->getTargetTriple().getArch() == Triple::x86_64) {
1892 if (!JumpTableInFunctionSection) {
1893 // We can always create relative relocations, so use another section
1894 // that can be marked non-executable.
1895 return false;
1896 }
1897 }
1898 return TargetLoweringObjectFile::shouldPutJumpTableInFunctionSection(
1899 UsesLabelDifference, F);
1900}
1901
1902void TargetLoweringObjectFileCOFF::emitModuleMetadata(MCStreamer &Streamer,
1903 Module &M) const {
1904 emitLinkerDirectives(Streamer, M);
1905
1906 unsigned Version = 0;
1907 unsigned Flags = 0;
1908 StringRef Section;
1909
1910 GetObjCImageInfo(M, Version, Flags, Section);
1911 if (!Section.empty()) {
1912 auto &C = getContext();
1913 auto *S = C.getCOFFSection(Section, Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1914 COFF::IMAGE_SCN_MEM_READ);
1915 Streamer.switchSection(Section: S);
1916 Streamer.emitLabel(Symbol: C.getOrCreateSymbol(Name: StringRef("OBJC_IMAGE_INFO")));
1917 Streamer.emitInt32(Value: Version);
1918 Streamer.emitInt32(Value: Flags);
1919 Streamer.addBlankLine();
1920 }
1921
1922 emitCGProfileMetadata(Streamer, M);
1923 emitPseudoProbeDescMetadata(Streamer, M, COMDATSymEmitter: [](MCStreamer &Streamer) {
1924 if (MCSymbol *Sym =
1925 static_cast<MCSectionCOFF *>(Streamer.getCurrentSectionOnly())
1926 ->getCOMDATSymbol())
1927 if (Sym->isUndefined()) {
1928 // COMDAT symbol must be external to perform deduplication.
1929 Streamer.emitSymbolAttribute(Symbol: Sym, Attribute: MCSA_Global);
1930 Streamer.emitLabel(Symbol: Sym);
1931 }
1932 });
1933}
1934
1935void TargetLoweringObjectFileCOFF::emitLinkerDirectives(
1936 MCStreamer &Streamer, Module &M) const {
1937 if (NamedMDNode *LinkerOptions = M.getNamedMetadata(Name: "llvm.linker.options")) {
1938 // Emit the linker options to the linker .drectve section. According to the
1939 // spec, this section is a space-separated string containing flags for
1940 // linker.
1941 MCSection *Sec = getDrectveSection();
1942 Streamer.switchSection(Section: Sec);
1943 for (const auto *Option : LinkerOptions->operands()) {
1944 for (const auto &Piece : cast<MDNode>(Val: Option)->operands()) {
1945 // Lead with a space for consistency with our dllexport implementation.
1946 std::string Directive(" ");
1947 Directive.append(str: std::string(cast<MDString>(Val: Piece)->getString()));
1948 Streamer.emitBytes(Data: Directive);
1949 }
1950 }
1951 }
1952
1953 // Emit /EXPORT: flags for each exported global as necessary.
1954 std::string Flags;
1955 for (const GlobalValue &GV : M.global_values()) {
1956 raw_string_ostream OS(Flags);
1957 emitLinkerFlagsForGlobalCOFF(OS, GV: &GV, TT: getContext().getTargetTriple(),
1958 Mangler&: getMangler());
1959 if (!Flags.empty()) {
1960 Streamer.switchSection(Section: getDrectveSection());
1961 Streamer.emitBytes(Data: Flags);
1962 }
1963 Flags.clear();
1964 }
1965
1966 // Emit /INCLUDE: flags for each used global as necessary.
1967 if (const auto *LU = M.getNamedGlobal(Name: "llvm.used")) {
1968 assert(LU->hasInitializer() && "expected llvm.used to have an initializer");
1969 assert(isa<ArrayType>(LU->getValueType()) &&
1970 "expected llvm.used to be an array type");
1971 if (const auto *A = cast<ConstantArray>(Val: LU->getInitializer())) {
1972 for (const Value *Op : A->operands()) {
1973 const auto *GV = cast<GlobalValue>(Val: Op->stripPointerCasts());
1974 // Global symbols with internal or private linkage are not visible to
1975 // the linker, and thus would cause an error when the linker tried to
1976 // preserve the symbol due to the `/include:` directive.
1977 if (GV->hasLocalLinkage())
1978 continue;
1979
1980 raw_string_ostream OS(Flags);
1981 emitLinkerFlagsForUsedCOFF(OS, GV, T: getContext().getTargetTriple(),
1982 M&: getMangler());
1983
1984 if (!Flags.empty()) {
1985 Streamer.switchSection(Section: getDrectveSection());
1986 Streamer.emitBytes(Data: Flags);
1987 }
1988 Flags.clear();
1989 }
1990 }
1991 }
1992}
1993
1994void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
1995 const TargetMachine &TM) {
1996 TargetLoweringObjectFile::Initialize(ctx&: Ctx, TM);
1997 this->TM = &TM;
1998 const Triple &T = TM.getTargetTriple();
1999 if (T.isWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
2000 StaticCtorSection =
2001 Ctx.getCOFFSection(Section: ".CRT$XCU", Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2002 COFF::IMAGE_SCN_MEM_READ);
2003 StaticDtorSection =
2004 Ctx.getCOFFSection(Section: ".CRT$XTX", Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2005 COFF::IMAGE_SCN_MEM_READ);
2006 } else {
2007 StaticCtorSection = Ctx.getCOFFSection(
2008 Section: ".ctors", Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2009 COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE);
2010 StaticDtorSection = Ctx.getCOFFSection(
2011 Section: ".dtors", Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2012 COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE);
2013 }
2014}
2015
2016static MCSectionCOFF *getCOFFStaticStructorSection(MCContext &Ctx,
2017 const Triple &T, bool IsCtor,
2018 unsigned Priority,
2019 const MCSymbol *KeySym,
2020 MCSectionCOFF *Default) {
2021 if (T.isWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
2022 // If the priority is the default, use .CRT$XCU, possibly associative.
2023 if (Priority == 65535)
2024 return Ctx.getAssociativeCOFFSection(Sec: Default, KeySym, UniqueID: 0);
2025
2026 // Otherwise, we need to compute a new section name. Low priorities should
2027 // run earlier. The linker will sort sections ASCII-betically, and we need a
2028 // string that sorts between .CRT$XCA and .CRT$XCU. In the general case, we
2029 // make a name like ".CRT$XCT12345", since that runs before .CRT$XCU. Really
2030 // low priorities need to sort before 'L', since the CRT uses that
2031 // internally, so we use ".CRT$XCA00001" for them. We have a contract with
2032 // the frontend that "init_seg(compiler)" corresponds to priority 200 and
2033 // "init_seg(lib)" corresponds to priority 400, and those respectively use
2034 // 'C' and 'L' without the priority suffix. Priorities between 200 and 400
2035 // use 'C' with the priority as a suffix.
2036 SmallString<24> Name;
2037 char LastLetter = 'T';
2038 bool AddPrioritySuffix = Priority != 200 && Priority != 400;
2039 if (Priority < 200)
2040 LastLetter = 'A';
2041 else if (Priority < 400)
2042 LastLetter = 'C';
2043 else if (Priority == 400)
2044 LastLetter = 'L';
2045 raw_svector_ostream OS(Name);
2046 OS << ".CRT$X" << (IsCtor ? "C" : "T") << LastLetter;
2047 if (AddPrioritySuffix)
2048 OS << format(Fmt: "%05u", Vals: Priority);
2049 MCSectionCOFF *Sec = Ctx.getCOFFSection(
2050 Section: Name, Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ);
2051 return Ctx.getAssociativeCOFFSection(Sec, KeySym, UniqueID: 0);
2052 }
2053
2054 std::string Name = IsCtor ? ".ctors" : ".dtors";
2055 if (Priority != 65535)
2056 raw_string_ostream(Name) << format(Fmt: ".%05u", Vals: 65535 - Priority);
2057
2058 return Ctx.getAssociativeCOFFSection(
2059 Sec: Ctx.getCOFFSection(Section: Name, Characteristics: COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2060 COFF::IMAGE_SCN_MEM_READ |
2061 COFF::IMAGE_SCN_MEM_WRITE),
2062 KeySym, UniqueID: 0);
2063}
2064
2065MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection(
2066 unsigned Priority, const MCSymbol *KeySym) const {
2067 return getCOFFStaticStructorSection(
2068 Ctx&: getContext(), T: getContext().getTargetTriple(), IsCtor: true, Priority, KeySym,
2069 Default: static_cast<MCSectionCOFF *>(StaticCtorSection));
2070}
2071
2072MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection(
2073 unsigned Priority, const MCSymbol *KeySym) const {
2074 return getCOFFStaticStructorSection(
2075 Ctx&: getContext(), T: getContext().getTargetTriple(), IsCtor: false, Priority, KeySym,
2076 Default: static_cast<MCSectionCOFF *>(StaticDtorSection));
2077}
2078
2079const MCExpr *TargetLoweringObjectFileCOFF::lowerRelativeReference(
2080 const GlobalValue *LHS, const GlobalValue *RHS, int64_t Addend,
2081 std::optional<int64_t> PCRelativeOffset, const TargetMachine &TM) const {
2082 const Triple &T = TM.getTargetTriple();
2083 if (T.isOSCygMing())
2084 return nullptr;
2085
2086 // Our symbols should exist in address space zero, cowardly no-op if
2087 // otherwise.
2088 if (LHS->getType()->getPointerAddressSpace() != 0 ||
2089 RHS->getType()->getPointerAddressSpace() != 0)
2090 return nullptr;
2091
2092 // Both ptrtoint instructions must wrap global objects:
2093 // - Only global variables are eligible for image relative relocations.
2094 // - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable.
2095 // We expect __ImageBase to be a global variable without a section, externally
2096 // defined.
2097 //
2098 // It should look something like this: @__ImageBase = external constant i8
2099 if (!isa<GlobalObject>(Val: LHS) || !isa<GlobalVariable>(Val: RHS) ||
2100 LHS->isThreadLocal() || RHS->isThreadLocal() ||
2101 RHS->getName() != "__ImageBase" || !RHS->hasExternalLinkage() ||
2102 cast<GlobalVariable>(Val: RHS)->hasInitializer() || RHS->hasSection())
2103 return nullptr;
2104
2105 const MCExpr *Res = MCSymbolRefExpr::create(
2106 Symbol: TM.getSymbol(GV: LHS), specifier: MCSymbolRefExpr::VK_COFF_IMGREL32, Ctx&: getContext());
2107 if (Addend != 0)
2108 Res = MCBinaryExpr::createAdd(
2109 LHS: Res, RHS: MCConstantExpr::create(Value: Addend, Ctx&: getContext()), Ctx&: getContext());
2110 return Res;
2111}
2112
2113static std::string APIntToHexString(const APInt &AI) {
2114 unsigned Width = (AI.getBitWidth() / 8) * 2;
2115 std::string HexString = toString(I: AI, Radix: 16, /*Signed=*/false);
2116 llvm::transform(Range&: HexString, d_first: HexString.begin(), F: tolower);
2117 unsigned Size = HexString.size();
2118 assert(Width >= Size && "hex string is too large!");
2119 HexString.insert(p: HexString.begin(), n: Width - Size, c: '0');
2120
2121 return HexString;
2122}
2123
2124static std::string scalarConstantToHexString(const Constant *C) {
2125 Type *Ty = C->getType();
2126 if (isa<UndefValue>(Val: C)) {
2127 return APIntToHexString(AI: APInt::getZero(numBits: Ty->getPrimitiveSizeInBits()));
2128 } else if (const auto *CFP = dyn_cast<ConstantFP>(Val: C)) {
2129 if (CFP->getType()->isFloatingPointTy())
2130 return APIntToHexString(AI: CFP->getValueAPF().bitcastToAPInt());
2131
2132 std::string HexString;
2133 unsigned NumElements =
2134 cast<FixedVectorType>(Val: CFP->getType())->getNumElements();
2135 for (unsigned I = 0; I < NumElements; ++I)
2136 HexString += APIntToHexString(AI: CFP->getValueAPF().bitcastToAPInt());
2137 return HexString;
2138 } else if (const auto *CI = dyn_cast<ConstantInt>(Val: C)) {
2139 if (CI->getType()->isIntegerTy())
2140 return APIntToHexString(AI: CI->getValue());
2141
2142 std::string HexString;
2143 unsigned NumElements =
2144 cast<FixedVectorType>(Val: CI->getType())->getNumElements();
2145 for (unsigned I = 0; I < NumElements; ++I)
2146 HexString += APIntToHexString(AI: CI->getValue());
2147 return HexString;
2148 } else {
2149 unsigned NumElements;
2150 if (auto *VTy = dyn_cast<VectorType>(Val: Ty))
2151 NumElements = cast<FixedVectorType>(Val: VTy)->getNumElements();
2152 else
2153 NumElements = Ty->getArrayNumElements();
2154 std::string HexString;
2155 for (int I = NumElements - 1, E = -1; I != E; --I)
2156 HexString += scalarConstantToHexString(C: C->getAggregateElement(Elt: I));
2157 return HexString;
2158 }
2159}
2160
2161MCSection *TargetLoweringObjectFileCOFF::getSectionForConstant(
2162 const DataLayout &DL, SectionKind Kind, const Constant *C,
2163 Align &Alignment) const {
2164 if (Kind.isMergeableConst() && C &&
2165 getContext().getAsmInfo()->hasCOFFComdatConstants()) {
2166 // This creates comdat sections with the given symbol name, but unless
2167 // AsmPrinter::GetCPISymbol actually makes the symbol global, the symbol
2168 // will be created with a null storage class, which makes GNU binutils
2169 // error out.
2170 const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
2171 COFF::IMAGE_SCN_MEM_READ |
2172 COFF::IMAGE_SCN_LNK_COMDAT;
2173 std::string COMDATSymName;
2174 if (Kind.isMergeableConst4()) {
2175 if (Alignment <= 4) {
2176 COMDATSymName = "__real@" + scalarConstantToHexString(C);
2177 Alignment = Align(4);
2178 }
2179 } else if (Kind.isMergeableConst8()) {
2180 if (Alignment <= 8) {
2181 COMDATSymName = "__real@" + scalarConstantToHexString(C);
2182 Alignment = Align(8);
2183 }
2184 } else if (Kind.isMergeableConst16()) {
2185 // FIXME: These may not be appropriate for non-x86 architectures.
2186 if (Alignment <= 16) {
2187 COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
2188 Alignment = Align(16);
2189 }
2190 } else if (Kind.isMergeableConst32()) {
2191 if (Alignment <= 32) {
2192 COMDATSymName = "__ymm@" + scalarConstantToHexString(C);
2193 Alignment = Align(32);
2194 }
2195 }
2196
2197 if (!COMDATSymName.empty())
2198 return getContext().getCOFFSection(Section: ".rdata", Characteristics,
2199 COMDATSymName,
2200 Selection: COFF::IMAGE_COMDAT_SELECT_ANY);
2201 }
2202
2203 return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C,
2204 Alignment);
2205}
2206
2207//===----------------------------------------------------------------------===//
2208// Wasm
2209//===----------------------------------------------------------------------===//
2210
2211static const Comdat *getWasmComdat(const GlobalValue *GV) {
2212 const Comdat *C = GV->getComdat();
2213 if (!C)
2214 return nullptr;
2215
2216 if (C->getSelectionKind() != Comdat::Any)
2217 report_fatal_error(reason: "WebAssembly COMDATs only support "
2218 "SelectionKind::Any, '" + C->getName() + "' cannot be "
2219 "lowered.");
2220
2221 return C;
2222}
2223
2224static unsigned getWasmSectionFlags(SectionKind K, bool Retain) {
2225 unsigned Flags = 0;
2226
2227 if (K.isThreadLocal())
2228 Flags |= wasm::WASM_SEG_FLAG_TLS;
2229
2230 if (K.isMergeableCString())
2231 Flags |= wasm::WASM_SEG_FLAG_STRINGS;
2232
2233 if (Retain)
2234 Flags |= wasm::WASM_SEG_FLAG_RETAIN;
2235
2236 // TODO(sbc): Add suport for K.isMergeableConst()
2237
2238 return Flags;
2239}
2240
2241void TargetLoweringObjectFileWasm::getModuleMetadata(Module &M) {
2242 SmallVector<GlobalValue *, 4> Vec;
2243 collectUsedGlobalVariables(M, Vec, CompilerUsed: false);
2244 for (GlobalValue *GV : Vec)
2245 if (auto *GO = dyn_cast<GlobalObject>(Val: GV))
2246 Used.insert(Ptr: GO);
2247}
2248
2249MCSection *TargetLoweringObjectFileWasm::getExplicitSectionGlobal(
2250 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2251 // We don't support explict section names for functions in the wasm object
2252 // format. Each function has to be in its own unique section.
2253 if (isa<Function>(Val: GO)) {
2254 return SelectSectionForGlobal(GO, Kind, TM);
2255 }
2256
2257 StringRef Name = GO->getSection();
2258
2259 // Certain data sections we treat as named custom sections rather than
2260 // segments within the data section.
2261 // This could be avoided if all data segements (the wasm sense) were
2262 // represented as their own sections (in the llvm sense).
2263 // TODO(sbc): https://github.com/WebAssembly/tool-conventions/issues/138
2264 if (Name == getInstrProfSectionName(IPSK: IPSK_covmap, OF: Triple::Wasm,
2265 /*AddSegmentInfo=*/false) ||
2266 Name == getInstrProfSectionName(IPSK: IPSK_covfun, OF: Triple::Wasm,
2267 /*AddSegmentInfo=*/false) ||
2268 Name == ".llvmbc" || Name == ".llvmcmd")
2269 Kind = SectionKind::getMetadata();
2270
2271 StringRef Group = "";
2272 if (const Comdat *C = getWasmComdat(GV: GO)) {
2273 Group = C->getName();
2274 }
2275
2276 unsigned Flags = getWasmSectionFlags(K: Kind, Retain: Used.count(Ptr: GO));
2277 MCSectionWasm *Section = getContext().getWasmSection(Section: Name, K: Kind, Flags, Group,
2278 UniqueID: MCSection::NonUniqueID);
2279
2280 return Section;
2281}
2282
2283static MCSectionWasm *
2284selectWasmSectionForGlobal(MCContext &Ctx, const GlobalObject *GO,
2285 SectionKind Kind, Mangler &Mang,
2286 const TargetMachine &TM, bool EmitUniqueSection,
2287 unsigned *NextUniqueID, bool Retain) {
2288 StringRef Group = "";
2289 if (const Comdat *C = getWasmComdat(GV: GO)) {
2290 Group = C->getName();
2291 }
2292
2293 bool UniqueSectionNames = TM.getUniqueSectionNames();
2294 SmallString<128> Name = getSectionPrefixForGlobal(Kind, /*IsLarge=*/false);
2295
2296 if (const auto *F = dyn_cast<Function>(Val: GO)) {
2297 const auto &OptionalPrefix = F->getSectionPrefix();
2298 if (OptionalPrefix)
2299 raw_svector_ostream(Name) << '.' << *OptionalPrefix;
2300 }
2301
2302 if (EmitUniqueSection && UniqueSectionNames) {
2303 Name.push_back(Elt: '.');
2304 TM.getNameWithPrefix(Name, GV: GO, Mang, MayAlwaysUsePrivate: true);
2305 }
2306 unsigned UniqueID = MCSection::NonUniqueID;
2307 if (EmitUniqueSection && !UniqueSectionNames) {
2308 UniqueID = *NextUniqueID;
2309 (*NextUniqueID)++;
2310 }
2311
2312 unsigned Flags = getWasmSectionFlags(K: Kind, Retain);
2313 return Ctx.getWasmSection(Section: Name, K: Kind, Flags, Group, UniqueID);
2314}
2315
2316MCSection *TargetLoweringObjectFileWasm::SelectSectionForGlobal(
2317 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2318
2319 if (Kind.isCommon())
2320 report_fatal_error(reason: "mergable sections not supported yet on wasm");
2321
2322 // If we have -ffunction-section or -fdata-section then we should emit the
2323 // global value to a uniqued section specifically for it.
2324 bool EmitUniqueSection = false;
2325 if (Kind.isText())
2326 EmitUniqueSection = TM.getFunctionSections();
2327 else
2328 EmitUniqueSection = TM.getDataSections();
2329 EmitUniqueSection |= GO->hasComdat();
2330 bool Retain = Used.count(Ptr: GO);
2331 EmitUniqueSection |= Retain;
2332
2333 return selectWasmSectionForGlobal(Ctx&: getContext(), GO, Kind, Mang&: getMangler(), TM,
2334 EmitUniqueSection, NextUniqueID: &NextUniqueID, Retain);
2335}
2336
2337bool TargetLoweringObjectFileWasm::shouldPutJumpTableInFunctionSection(
2338 bool UsesLabelDifference, const Function &F) const {
2339 // We can always create relative relocations, so use another section
2340 // that can be marked non-executable.
2341 return false;
2342}
2343
2344void TargetLoweringObjectFileWasm::InitializeWasm() {
2345 StaticCtorSection =
2346 getContext().getWasmSection(Section: ".init_array", K: SectionKind::getData());
2347
2348 // We don't use PersonalityEncoding and LSDAEncoding because we don't emit
2349 // .cfi directives. We use TTypeEncoding to encode typeinfo global variables.
2350 TTypeEncoding = dwarf::DW_EH_PE_absptr;
2351}
2352
2353MCSection *TargetLoweringObjectFileWasm::getStaticCtorSection(
2354 unsigned Priority, const MCSymbol *KeySym) const {
2355 return Priority == UINT16_MAX ?
2356 StaticCtorSection :
2357 getContext().getWasmSection(Section: ".init_array." + utostr(X: Priority),
2358 K: SectionKind::getData());
2359}
2360
2361MCSection *TargetLoweringObjectFileWasm::getStaticDtorSection(
2362 unsigned Priority, const MCSymbol *KeySym) const {
2363 report_fatal_error(reason: "@llvm.global_dtors should have been lowered already");
2364}
2365
2366//===----------------------------------------------------------------------===//
2367// XCOFF
2368//===----------------------------------------------------------------------===//
2369bool TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(
2370 const MachineFunction *MF) {
2371 if (!MF->getLandingPads().empty())
2372 return true;
2373
2374 const Function &F = MF->getFunction();
2375 if (!F.hasPersonalityFn() || !F.needsUnwindTableEntry())
2376 return false;
2377
2378 const GlobalValue *Per =
2379 dyn_cast<GlobalValue>(Val: F.getPersonalityFn()->stripPointerCasts());
2380 assert(Per && "Personality routine is not a GlobalValue type.");
2381 if (isNoOpWithoutInvoke(Pers: classifyEHPersonality(Pers: Per)))
2382 return false;
2383
2384 return true;
2385}
2386
2387bool TargetLoweringObjectFileXCOFF::ShouldSetSSPCanaryBitInTB(
2388 const MachineFunction *MF) {
2389 const Function &F = MF->getFunction();
2390 if (!F.hasStackProtectorFnAttr())
2391 return false;
2392 // FIXME: check presence of canary word
2393 // There are cases that the stack protectors are not really inserted even if
2394 // the attributes are on.
2395 return true;
2396}
2397
2398MCSymbol *
2399TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(const MachineFunction *MF) {
2400 auto *EHInfoSym =
2401 static_cast<MCSymbolXCOFF *>(MF->getContext().getOrCreateSymbol(
2402 Name: "__ehinfo." + Twine(MF->getFunctionNumber())));
2403 EHInfoSym->setEHInfo();
2404 return EHInfoSym;
2405}
2406
2407MCSymbol *
2408TargetLoweringObjectFileXCOFF::getTargetSymbol(const GlobalValue *GV,
2409 const TargetMachine &TM) const {
2410 // We always use a qualname symbol for a GV that represents
2411 // a declaration, a function descriptor, or a common symbol. An IFunc is
2412 // lowered as a special trampoline function which has an entry point and a
2413 // descriptor.
2414 // If a GV represents a GlobalVariable and -fdata-sections is enabled, we
2415 // also return a qualname so that a label symbol could be avoided.
2416 // It is inherently ambiguous when the GO represents the address of a
2417 // function, as the GO could either represent a function descriptor or a
2418 // function entry point. We choose to always return a function descriptor
2419 // here.
2420 if (const GlobalObject *GO = dyn_cast<GlobalObject>(Val: GV)) {
2421 if (GO->isDeclarationForLinker())
2422 return static_cast<const MCSectionXCOFF *>(
2423 getSectionForExternalReference(GO, TM))
2424 ->getQualNameSymbol();
2425
2426 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(Val: GV))
2427 if (GVar->hasAttribute(Kind: "toc-data"))
2428 return static_cast<const MCSectionXCOFF *>(
2429 SectionForGlobal(GO: GVar, Kind: SectionKind::getData(), TM))
2430 ->getQualNameSymbol();
2431
2432 if (isa<GlobalIFunc>(Val: GO))
2433 return static_cast<const MCSectionXCOFF *>(
2434 getSectionForFunctionDescriptor(F: GO, TM))
2435 ->getQualNameSymbol();
2436
2437 SectionKind GOKind = getKindForGlobal(GO, TM);
2438 if (GOKind.isText())
2439 return static_cast<const MCSectionXCOFF *>(
2440 getSectionForFunctionDescriptor(F: cast<Function>(Val: GO), TM))
2441 ->getQualNameSymbol();
2442 if ((TM.getDataSections() && !GO->hasSection()) || GO->hasCommonLinkage() ||
2443 GOKind.isBSSLocal() || GOKind.isThreadBSSLocal())
2444 return static_cast<const MCSectionXCOFF *>(
2445 SectionForGlobal(GO, Kind: GOKind, TM))
2446 ->getQualNameSymbol();
2447 }
2448
2449 // For all other cases, fall back to getSymbol to return the unqualified name.
2450 return nullptr;
2451}
2452
2453MCSection *TargetLoweringObjectFileXCOFF::getExplicitSectionGlobal(
2454 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2455 if (!GO->hasSection())
2456 report_fatal_error(reason: "#pragma clang section is not yet supported");
2457
2458 StringRef SectionName = GO->getSection();
2459
2460 // Handle the XCOFF::TD case first, then deal with the rest.
2461 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(Val: GO))
2462 if (GVar->hasAttribute(Kind: "toc-data"))
2463 return getContext().getXCOFFSection(
2464 Section: SectionName, K: Kind,
2465 CsectProp: XCOFF::CsectProperties(/*MappingClass*/ XCOFF::XMC_TD, XCOFF::XTY_SD),
2466 /* MultiSymbolsAllowed*/ true);
2467
2468 XCOFF::StorageMappingClass MappingClass;
2469 if (Kind.isText())
2470 MappingClass = XCOFF::XMC_PR;
2471 else if (Kind.isData() || Kind.isBSS())
2472 MappingClass = XCOFF::XMC_RW;
2473 else if (Kind.isReadOnlyWithRel())
2474 MappingClass =
2475 TM.Options.XCOFFReadOnlyPointers ? XCOFF::XMC_RO : XCOFF::XMC_RW;
2476 else if (Kind.isReadOnly())
2477 MappingClass = XCOFF::XMC_RO;
2478 else
2479 report_fatal_error(reason: "XCOFF other section types not yet implemented.");
2480
2481 return getContext().getXCOFFSection(
2482 Section: SectionName, K: Kind, CsectProp: XCOFF::CsectProperties(MappingClass, XCOFF::XTY_SD),
2483 /* MultiSymbolsAllowed*/ true);
2484}
2485
2486MCSection *TargetLoweringObjectFileXCOFF::getSectionForExternalReference(
2487 const GlobalObject *GO, const TargetMachine &TM) const {
2488 assert(GO->isDeclarationForLinker() &&
2489 "Tried to get ER section for a defined global.");
2490
2491 SmallString<128> Name;
2492 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2493
2494 // AIX TLS local-dynamic does not need the external reference for the
2495 // "_$TLSML" symbol.
2496 if (GO->getThreadLocalMode() == GlobalVariable::LocalDynamicTLSModel &&
2497 GO->hasName() && GO->getName() == "_$TLSML") {
2498 return getContext().getXCOFFSection(
2499 Section: Name, K: SectionKind::getData(),
2500 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_TC, XCOFF::XTY_SD));
2501 }
2502
2503 XCOFF::StorageMappingClass SMC =
2504 isa<Function>(Val: GO) ? XCOFF::XMC_DS : XCOFF::XMC_UA;
2505 if (GO->isThreadLocal())
2506 SMC = XCOFF::XMC_UL;
2507
2508 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(Val: GO))
2509 if (GVar->hasAttribute(Kind: "toc-data"))
2510 SMC = XCOFF::XMC_TD;
2511
2512 // Externals go into a csect of type ER.
2513 return getContext().getXCOFFSection(
2514 Section: Name, K: SectionKind::getMetadata(),
2515 CsectProp: XCOFF::CsectProperties(SMC, XCOFF::XTY_ER));
2516}
2517
2518MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
2519 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2520 // Handle the XCOFF::TD case first, then deal with the rest.
2521 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(Val: GO))
2522 if (GVar->hasAttribute(Kind: "toc-data")) {
2523 SmallString<128> Name;
2524 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2525 XCOFF::SymbolType symType =
2526 GO->hasCommonLinkage() ? XCOFF::XTY_CM : XCOFF::XTY_SD;
2527 return getContext().getXCOFFSection(
2528 Section: Name, K: Kind, CsectProp: XCOFF::CsectProperties(XCOFF::XMC_TD, symType),
2529 /* MultiSymbolsAllowed*/ true);
2530 }
2531
2532 // Common symbols go into a csect with matching name which will get mapped
2533 // into the .bss section.
2534 // Zero-initialized local TLS symbols go into a csect with matching name which
2535 // will get mapped into the .tbss section.
2536 if (Kind.isBSSLocal() || GO->hasCommonLinkage() || Kind.isThreadBSSLocal()) {
2537 SmallString<128> Name;
2538 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2539 XCOFF::StorageMappingClass SMC = Kind.isBSSLocal() ? XCOFF::XMC_BS
2540 : Kind.isCommon() ? XCOFF::XMC_RW
2541 : XCOFF::XMC_UL;
2542 return getContext().getXCOFFSection(
2543 Section: Name, K: Kind, CsectProp: XCOFF::CsectProperties(SMC, XCOFF::XTY_CM));
2544 }
2545
2546 if (Kind.isText()) {
2547 if (TM.getFunctionSections()) {
2548 return static_cast<const MCSymbolXCOFF *>(
2549 getFunctionEntryPointSymbol(Func: GO, TM))
2550 ->getRepresentedCsect();
2551 }
2552 return TextSection;
2553 }
2554
2555 if (TM.Options.XCOFFReadOnlyPointers && Kind.isReadOnlyWithRel()) {
2556 if (!TM.getDataSections())
2557 report_fatal_error(
2558 reason: "ReadOnlyPointers is supported only if data sections is turned on");
2559
2560 SmallString<128> Name;
2561 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2562 return getContext().getXCOFFSection(
2563 Section: Name, K: SectionKind::getReadOnly(),
2564 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD));
2565 }
2566
2567 // For BSS kind, zero initialized data must be emitted to the .data section
2568 // because external linkage control sections that get mapped to the .bss
2569 // section will be linked as tentative definitions, which is only appropriate
2570 // for SectionKind::Common.
2571 if (Kind.isData() || Kind.isReadOnlyWithRel() || Kind.isBSS()) {
2572 if (TM.getDataSections()) {
2573 SmallString<128> Name;
2574 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2575 return getContext().getXCOFFSection(
2576 Section: Name, K: SectionKind::getData(),
2577 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_RW, XCOFF::XTY_SD));
2578 }
2579 return DataSection;
2580 }
2581
2582 if (Kind.isReadOnly()) {
2583 if (TM.getDataSections()) {
2584 SmallString<128> Name;
2585 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2586 return getContext().getXCOFFSection(
2587 Section: Name, K: SectionKind::getReadOnly(),
2588 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD));
2589 }
2590 return ReadOnlySection;
2591 }
2592
2593 // External/weak TLS data and initialized local TLS data are not eligible
2594 // to be put into common csect. If data sections are enabled, thread
2595 // data are emitted into separate sections. Otherwise, thread data
2596 // are emitted into the .tdata section.
2597 if (Kind.isThreadLocal()) {
2598 if (TM.getDataSections()) {
2599 SmallString<128> Name;
2600 getNameWithPrefix(OutName&: Name, GV: GO, TM);
2601 return getContext().getXCOFFSection(
2602 Section: Name, K: Kind, CsectProp: XCOFF::CsectProperties(XCOFF::XMC_TL, XCOFF::XTY_SD));
2603 }
2604 return TLSDataSection;
2605 }
2606
2607 report_fatal_error(reason: "XCOFF other section types not yet implemented.");
2608}
2609
2610MCSection *TargetLoweringObjectFileXCOFF::getSectionForJumpTable(
2611 const Function &F, const TargetMachine &TM) const {
2612 assert (!F.getComdat() && "Comdat not supported on XCOFF.");
2613
2614 if (!TM.getFunctionSections())
2615 return ReadOnlySection;
2616
2617 // If the function can be removed, produce a unique section so that
2618 // the table doesn't prevent the removal.
2619 SmallString<128> NameStr(".rodata.jmp..");
2620 getNameWithPrefix(OutName&: NameStr, GV: &F, TM);
2621 return getContext().getXCOFFSection(
2622 Section: NameStr, K: SectionKind::getReadOnly(),
2623 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD));
2624}
2625
2626bool TargetLoweringObjectFileXCOFF::shouldPutJumpTableInFunctionSection(
2627 bool UsesLabelDifference, const Function &F) const {
2628 return false;
2629}
2630
2631/// Given a mergeable constant with the specified size and relocation
2632/// information, return a section that it should be placed in.
2633MCSection *TargetLoweringObjectFileXCOFF::getSectionForConstant(
2634 const DataLayout &DL, SectionKind Kind, const Constant *C,
2635 Align &Alignment) const {
2636 // TODO: Enable emiting constant pool to unique sections when we support it.
2637 if (Alignment > Align(16))
2638 report_fatal_error(reason: "Alignments greater than 16 not yet supported.");
2639
2640 if (Alignment == Align(8)) {
2641 assert(ReadOnly8Section && "Section should always be initialized.");
2642 return ReadOnly8Section;
2643 }
2644
2645 if (Alignment == Align(16)) {
2646 assert(ReadOnly16Section && "Section should always be initialized.");
2647 return ReadOnly16Section;
2648 }
2649
2650 return ReadOnlySection;
2651}
2652
2653void TargetLoweringObjectFileXCOFF::Initialize(MCContext &Ctx,
2654 const TargetMachine &TgtM) {
2655 TargetLoweringObjectFile::Initialize(ctx&: Ctx, TM: TgtM);
2656 TTypeEncoding =
2657 dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_datarel |
2658 (TgtM.getTargetTriple().isArch32Bit() ? dwarf::DW_EH_PE_sdata4
2659 : dwarf::DW_EH_PE_sdata8);
2660 PersonalityEncoding = 0;
2661 LSDAEncoding = 0;
2662 CallSiteEncoding = dwarf::DW_EH_PE_udata4;
2663
2664 // AIX debug for thread local location is not ready. And for integrated as
2665 // mode, the relocatable address for the thread local variable will cause
2666 // linker error. So disable the location attribute generation for thread local
2667 // variables for now.
2668 // FIXME: when TLS debug on AIX is ready, remove this setting.
2669 SupportDebugThreadLocalLocation = false;
2670}
2671
2672MCSection *TargetLoweringObjectFileXCOFF::getStaticCtorSection(
2673 unsigned Priority, const MCSymbol *KeySym) const {
2674 report_fatal_error(reason: "no static constructor section on AIX");
2675}
2676
2677MCSection *TargetLoweringObjectFileXCOFF::getStaticDtorSection(
2678 unsigned Priority, const MCSymbol *KeySym) const {
2679 report_fatal_error(reason: "no static destructor section on AIX");
2680}
2681
2682XCOFF::StorageClass
2683TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(const GlobalValue *GV) {
2684 assert(!isa<GlobalIFunc>(GV) && "GlobalIFunc is not supported on AIX.");
2685
2686 switch (GV->getLinkage()) {
2687 case GlobalValue::InternalLinkage:
2688 case GlobalValue::PrivateLinkage:
2689 return XCOFF::C_HIDEXT;
2690 case GlobalValue::ExternalLinkage:
2691 case GlobalValue::CommonLinkage:
2692 case GlobalValue::AvailableExternallyLinkage:
2693 return XCOFF::C_EXT;
2694 case GlobalValue::ExternalWeakLinkage:
2695 case GlobalValue::LinkOnceAnyLinkage:
2696 case GlobalValue::LinkOnceODRLinkage:
2697 case GlobalValue::WeakAnyLinkage:
2698 case GlobalValue::WeakODRLinkage:
2699 return XCOFF::C_WEAKEXT;
2700 case GlobalValue::AppendingLinkage:
2701 report_fatal_error(
2702 reason: "There is no mapping that implements AppendingLinkage for XCOFF.");
2703 }
2704 llvm_unreachable("Unknown linkage type!");
2705}
2706
2707MCSymbol *TargetLoweringObjectFileXCOFF::getFunctionEntryPointSymbol(
2708 const GlobalValue *Func, const TargetMachine &TM) const {
2709 assert((isa<Function>(Func) || isa<GlobalIFunc>(Func) ||
2710 (isa<GlobalAlias>(Func) &&
2711 isa_and_nonnull<Function>(
2712 cast<GlobalAlias>(Func)->getAliaseeObject()))) &&
2713 "Func must be a function or an alias which has a function as base "
2714 "object.");
2715
2716 SmallString<128> NameStr;
2717 NameStr.push_back(Elt: '.');
2718 getNameWithPrefix(OutName&: NameStr, GV: Func, TM);
2719
2720 // When -function-sections is enabled and explicit section is not specified,
2721 // it's not necessary to emit function entry point label any more. We will use
2722 // function entry point csect instead. And for function delcarations, the
2723 // undefined symbols gets treated as csect with XTY_ER property.
2724 if (((TM.getFunctionSections() && !Func->hasSection()) ||
2725 Func->isDeclarationForLinker()) &&
2726 (isa<Function>(Val: Func) || isa<GlobalIFunc>(Val: Func))) {
2727 return getContext()
2728 .getXCOFFSection(
2729 Section: NameStr, K: SectionKind::getText(),
2730 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_PR, Func->isDeclarationForLinker()
2731 ? XCOFF::XTY_ER
2732 : XCOFF::XTY_SD))
2733 ->getQualNameSymbol();
2734 }
2735
2736 return getContext().getOrCreateSymbol(Name: NameStr);
2737}
2738
2739MCSection *TargetLoweringObjectFileXCOFF::getSectionForFunctionDescriptor(
2740 const GlobalObject *F, const TargetMachine &TM) const {
2741 assert((isa<Function>(F) || isa<GlobalIFunc>(F)) &&
2742 "F must be a function or ifunc object.");
2743 SmallString<128> NameStr;
2744 getNameWithPrefix(OutName&: NameStr, GV: F, TM);
2745 return getContext().getXCOFFSection(
2746 Section: NameStr, K: SectionKind::getData(),
2747 CsectProp: XCOFF::CsectProperties(XCOFF::XMC_DS, XCOFF::XTY_SD));
2748}
2749
2750MCSection *TargetLoweringObjectFileXCOFF::getSectionForTOCEntry(
2751 const MCSymbol *Sym, const TargetMachine &TM) const {
2752 const XCOFF::StorageMappingClass SMC = [](const MCSymbol *Sym,
2753 const TargetMachine &TM) {
2754 auto *XSym = static_cast<const MCSymbolXCOFF *>(Sym);
2755
2756 // The "_$TLSML" symbol for TLS local-dynamic mode requires XMC_TC,
2757 // otherwise the AIX assembler will complain.
2758 if (XSym->getSymbolTableName() == "_$TLSML")
2759 return XCOFF::XMC_TC;
2760
2761 // Use large code model toc entries for ehinfo symbols as they are
2762 // never referenced directly. The runtime loads their TOC entry
2763 // addresses from the trace-back table.
2764 if (XSym->isEHInfo())
2765 return XCOFF::XMC_TE;
2766
2767 // If the symbol does not have a code model specified use the module value.
2768 if (!XSym->hasPerSymbolCodeModel())
2769 return TM.getCodeModel() == CodeModel::Large ? XCOFF::XMC_TE
2770 : XCOFF::XMC_TC;
2771
2772 return XSym->getPerSymbolCodeModel() == MCSymbolXCOFF::CM_Large
2773 ? XCOFF::XMC_TE
2774 : XCOFF::XMC_TC;
2775 }(Sym, TM);
2776
2777 return getContext().getXCOFFSection(
2778 Section: static_cast<const MCSymbolXCOFF *>(Sym)->getSymbolTableName(),
2779 K: SectionKind::getData(), CsectProp: XCOFF::CsectProperties(SMC, XCOFF::XTY_SD));
2780}
2781
2782MCSection *TargetLoweringObjectFileXCOFF::getSectionForLSDA(
2783 const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const {
2784 auto *LSDA = static_cast<MCSectionXCOFF *>(LSDASection);
2785 if (TM.getFunctionSections()) {
2786 // If option -ffunction-sections is on, append the function name to the
2787 // name of the LSDA csect so that each function has its own LSDA csect.
2788 // This helps the linker to garbage-collect EH info of unused functions.
2789 SmallString<128> NameStr = LSDA->getName();
2790 raw_svector_ostream(NameStr) << '.' << F.getName();
2791 LSDA = getContext().getXCOFFSection(Section: NameStr, K: LSDA->getKind(),
2792 CsectProp: LSDA->getCsectProp());
2793 }
2794 return LSDA;
2795}
2796//===----------------------------------------------------------------------===//
2797// GOFF
2798//===----------------------------------------------------------------------===//
2799TargetLoweringObjectFileGOFF::TargetLoweringObjectFileGOFF() = default;
2800
2801void TargetLoweringObjectFileGOFF::getModuleMetadata(Module &M) {
2802 // Construct the default names for the root SD and the ADA PR symbol.
2803 StringRef FileName = sys::path::stem(path: M.getSourceFileName());
2804 if (FileName.size() > 1 && FileName.starts_with(Prefix: '<') &&
2805 FileName.ends_with(Suffix: '>'))
2806 FileName = FileName.substr(Start: 1, N: FileName.size() - 2);
2807 DefaultRootSDName = Twine(FileName).concat(Suffix: "#C").str();
2808 DefaultADAPRName = Twine(FileName).concat(Suffix: "#S").str();
2809 MCSectionGOFF *RootSD =
2810 static_cast<MCSectionGOFF *>(TextSection)->getParent();
2811 MCSectionGOFF *ADAPR = static_cast<MCSectionGOFF *>(ADASection);
2812 RootSD->setName(DefaultRootSDName);
2813 ADAPR->setName(DefaultADAPRName);
2814 // Initialize the label for the text section.
2815 MCSymbolGOFF *TextLD = static_cast<MCSymbolGOFF *>(
2816 getContext().getOrCreateSymbol(Name: RootSD->getName()));
2817 TextLD->setCodeData(GOFF::ESD_EXE_CODE);
2818 TextLD->setLinkage(GOFF::ESD_LT_XPLink);
2819 TextLD->setExternal(false);
2820 TextLD->setWeak(false);
2821 TextLD->setADA(ADAPR);
2822 TextSection->setBeginSymbol(TextLD);
2823 // Initialize the label for the ADA section.
2824 MCSymbolGOFF *ADASym = static_cast<MCSymbolGOFF *>(
2825 getContext().getOrCreateSymbol(Name: ADAPR->getName()));
2826 ADAPR->setBeginSymbol(ADASym);
2827}
2828
2829bool TargetLoweringObjectFileGOFF::shouldPutJumpTableInFunctionSection(
2830 bool UsesLabelDifference, const Function &F) const {
2831 return true;
2832}
2833
2834MCSection *TargetLoweringObjectFileGOFF::getExplicitSectionGlobal(
2835 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2836 return SelectSectionForGlobal(GO, Kind, TM);
2837}
2838
2839MCSection *TargetLoweringObjectFileGOFF::getSectionForLSDA(
2840 const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const {
2841 std::string Name = ".gcc_exception_table." + F.getName().str();
2842
2843 MCSectionGOFF *WSA = getContext().getGOFFSection(
2844 Kind: SectionKind::getMetadata(), Name: GOFF::CLASS_WSA,
2845 EDAttributes: GOFF::EDAttr{.IsReadOnly: false, .Rmode: GOFF::ESD_RMODE_64, .NameSpace: GOFF::ESD_NS_Parts,
2846 .TextStyle: GOFF::ESD_TS_ByteOriented, .BindAlgorithm: GOFF::ESD_BA_Merge,
2847 .LoadBehavior: GOFF::ESD_LB_Initial, .ReservedQwords: GOFF::ESD_RQ_0,
2848 .Alignment: GOFF::ESD_ALIGN_Fullword, .FillByteValue: 0},
2849 Parent: static_cast<MCSectionGOFF *>(TextSection)->getParent());
2850 return getContext().getGOFFSection(Kind: SectionKind::getData(), Name,
2851 PRAttributes: GOFF::PRAttr{.IsRenamable: true, .Executable: GOFF::ESD_EXE_DATA,
2852 .Linkage: GOFF::ESD_LT_XPLink,
2853 .BindingScope: GOFF::ESD_BSC_Section, .SortKey: 0},
2854 Parent: WSA);
2855}
2856
2857MCSection *TargetLoweringObjectFileGOFF::SelectSectionForGlobal(
2858 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
2859 auto *Symbol = TM.getSymbol(GV: GO);
2860
2861 if (Kind.isBSS() || Kind.isData()) {
2862 GOFF::ESDBindingScope PRBindingScope =
2863 GO->hasExternalLinkage()
2864 ? (GO->hasDefaultVisibility() ? GOFF::ESD_BSC_ImportExport
2865 : GOFF::ESD_BSC_Library)
2866 : GOFF::ESD_BSC_Section;
2867 GOFF::ESDBindingScope SDBindingScope =
2868 PRBindingScope == GOFF::ESD_BSC_Section ? GOFF::ESD_BSC_Section
2869 : GOFF::ESD_BSC_Unspecified;
2870 MaybeAlign Alignment;
2871 if (auto *F = dyn_cast<Function>(Val: GO))
2872 Alignment = F->getAlign();
2873 else if (auto *V = dyn_cast<GlobalVariable>(Val: GO))
2874 Alignment = V->getAlign();
2875 GOFF::ESDAlignment Align =
2876 Alignment ? static_cast<GOFF::ESDAlignment>(Log2(A: *Alignment))
2877 : GOFF::ESD_ALIGN_Doubleword;
2878 MCSectionGOFF *SD = getContext().getGOFFSection(
2879 Kind: SectionKind::getMetadata(), Name: Symbol->getName(),
2880 SDAttributes: GOFF::SDAttr{.TaskingBehavior: GOFF::ESD_TA_Unspecified, .BindingScope: SDBindingScope});
2881 MCSectionGOFF *ED = getContext().getGOFFSection(
2882 Kind: SectionKind::getMetadata(), Name: GOFF::CLASS_WSA,
2883 EDAttributes: GOFF::EDAttr{.IsReadOnly: false, .Rmode: GOFF::ESD_RMODE_64, .NameSpace: GOFF::ESD_NS_Parts,
2884 .TextStyle: GOFF::ESD_TS_ByteOriented, .BindAlgorithm: GOFF::ESD_BA_Merge,
2885 .LoadBehavior: GOFF::ESD_LB_Deferred, .ReservedQwords: GOFF::ESD_RQ_0, .Alignment: Align, .FillByteValue: 0},
2886 Parent: SD);
2887 return getContext().getGOFFSection(Kind, Name: Symbol->getName(),
2888 PRAttributes: GOFF::PRAttr{.IsRenamable: false, .Executable: GOFF::ESD_EXE_DATA,
2889 .Linkage: GOFF::ESD_LT_XPLink,
2890 .BindingScope: PRBindingScope, .SortKey: 0},
2891 Parent: ED);
2892 }
2893 return TextSection;
2894}
2895
2896MCSection *
2897TargetLoweringObjectFileGOFF::getStaticXtorSection(unsigned Priority) const {
2898 // XL C/C++ compilers on z/OS support priorities from min-int to max-int, with
2899 // sinit as source priority 0. For clang, sinit has source priority 65535.
2900 // For GOFF, the priority sortkey field is an unsigned value. So, we
2901 // add min-int to get sorting to work properly but also subtract the
2902 // clang sinit (65535) value so internally xl sinit and clang sinit have
2903 // the same unsigned GOFF priority sortkey field value (i.e. 0x80000000).
2904 static constexpr const uint32_t ClangDefaultSinitPriority = 65535;
2905 uint32_t Prio = Priority + (0x80000000 - ClangDefaultSinitPriority);
2906
2907 std::string Name(".xtor");
2908 if (Priority != ClangDefaultSinitPriority)
2909 Name = llvm::Twine(Name).concat(Suffix: ".").concat(Suffix: llvm::utostr(X: Priority)).str();
2910
2911 MCContext &Ctx = getContext();
2912 MCSectionGOFF *SInit = Ctx.getGOFFSection(
2913 Kind: SectionKind::getMetadata(), Name: GOFF::CLASS_SINIT,
2914 EDAttributes: GOFF::EDAttr{.IsReadOnly: false, .Rmode: GOFF::ESD_RMODE_64, .NameSpace: GOFF::ESD_NS_Parts,
2915 .TextStyle: GOFF::ESD_TS_ByteOriented, .BindAlgorithm: GOFF::ESD_BA_Merge,
2916 .LoadBehavior: GOFF::ESD_LB_Initial, .ReservedQwords: GOFF::ESD_RQ_0,
2917 .Alignment: GOFF::ESD_ALIGN_Doubleword},
2918 Parent: static_cast<const MCSectionGOFF *>(TextSection)->getParent());
2919
2920 MCSectionGOFF *Xtor = Ctx.getGOFFSection(
2921 Kind: SectionKind::getData(), Name,
2922 PRAttributes: GOFF::PRAttr{.IsRenamable: true, .Executable: GOFF::ESD_EXE_DATA, .Linkage: GOFF::ESD_LT_XPLink,
2923 .BindingScope: GOFF::ESD_BSC_Section, .SortKey: Prio},
2924 Parent: SInit);
2925 return Xtor;
2926}
2927