1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfDebug.h"
15 #include "ByteStreamer.h"
17 #include "DebugLocEntry.h"
18 #include "DwarfCompileUnit.h"
19 #include "DwarfExpression.h"
20 #include "DwarfUnit.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/CodeGen/DIE.h"
26 #include "llvm/CodeGen/MachineFunction.h"
27 #include "llvm/CodeGen/MachineModuleInfo.h"
28 #include "llvm/IR/Constants.h"
29 #include "llvm/IR/DIBuilder.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/Instructions.h"
33 #include "llvm/IR/Module.h"
34 #include "llvm/IR/ValueHandle.h"
35 #include "llvm/MC/MCAsmInfo.h"
36 #include "llvm/MC/MCSection.h"
37 #include "llvm/MC/MCStreamer.h"
38 #include "llvm/MC/MCSymbol.h"
39 #include "llvm/Support/CommandLine.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/Dwarf.h"
42 #include "llvm/Support/Endian.h"
43 #include "llvm/Support/ErrorHandling.h"
44 #include "llvm/Support/FormattedStream.h"
45 #include "llvm/Support/LEB128.h"
46 #include "llvm/Support/MD5.h"
47 #include "llvm/Support/Path.h"
48 #include "llvm/Support/Timer.h"
49 #include "llvm/Support/raw_ostream.h"
50 #include "llvm/Target/TargetFrameLowering.h"
51 #include "llvm/Target/TargetLoweringObjectFile.h"
52 #include "llvm/Target/TargetMachine.h"
53 #include "llvm/Target/TargetOptions.h"
54 #include "llvm/Target/TargetRegisterInfo.h"
55 #include "llvm/Target/TargetSubtargetInfo.h"
58 #define DEBUG_TYPE "dwarfdebug"
61 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
62 cl::desc("Disable debug info printing"));
64 static cl::opt<bool> UnknownLocations(
65 "use-unknown-locations", cl::Hidden,
66 cl::desc("Make an absence of debug location information explicit."),
70 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
71 cl::desc("Generate GNU-style pubnames and pubtypes"),
74 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
76 cl::desc("Generate dwarf aranges"),
80 enum DefaultOnOff { Default, Enable, Disable };
83 static cl::opt<DefaultOnOff>
84 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
85 cl::desc("Output prototype dwarf accelerator tables."),
86 cl::values(clEnumVal(Default, "Default for platform"),
87 clEnumVal(Enable, "Enabled"),
88 clEnumVal(Disable, "Disabled"), clEnumValEnd),
91 static cl::opt<DefaultOnOff>
92 SplitDwarf("split-dwarf", cl::Hidden,
93 cl::desc("Output DWARF5 split debug info."),
94 cl::values(clEnumVal(Default, "Default for platform"),
95 clEnumVal(Enable, "Enabled"),
96 clEnumVal(Disable, "Disabled"), clEnumValEnd),
99 static cl::opt<DefaultOnOff>
100 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
101 cl::desc("Generate DWARF pubnames and pubtypes sections"),
102 cl::values(clEnumVal(Default, "Default for platform"),
103 clEnumVal(Enable, "Enabled"),
104 clEnumVal(Disable, "Disabled"), clEnumValEnd),
107 static const char *const DWARFGroupName = "DWARF Emission";
108 static const char *const DbgTimerName = "DWARF Debug Writer";
110 void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) {
112 Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op)
113 : dwarf::OperationEncodingString(Op));
116 void DebugLocDwarfExpression::EmitSigned(int64_t Value) {
117 BS.EmitSLEB128(Value, Twine(Value));
120 void DebugLocDwarfExpression::EmitUnsigned(uint64_t Value) {
121 BS.EmitULEB128(Value, Twine(Value));
124 bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) {
125 // This information is not available while emitting .debug_loc entries.
129 //===----------------------------------------------------------------------===//
131 /// resolve - Look in the DwarfDebug map for the MDNode that
132 /// corresponds to the reference.
133 template <typename T> T *DbgVariable::resolve(TypedDINodeRef<T> Ref) const {
134 return DD->resolve(Ref);
137 bool DbgVariable::isBlockByrefVariable() const {
138 assert(Var && "Invalid complex DbgVariable!");
139 return Var->getType()
140 .resolve(DD->getTypeIdentifierMap())
141 ->isBlockByrefStruct();
144 const DIType *DbgVariable::getType() const {
145 DIType *Ty = Var->getType().resolve(DD->getTypeIdentifierMap());
146 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
147 // addresses instead.
148 if (Ty->isBlockByrefStruct()) {
149 /* Byref variables, in Blocks, are declared by the programmer as
150 "SomeType VarName;", but the compiler creates a
151 __Block_byref_x_VarName struct, and gives the variable VarName
152 either the struct, or a pointer to the struct, as its type. This
153 is necessary for various behind-the-scenes things the compiler
154 needs to do with by-reference variables in blocks.
156 However, as far as the original *programmer* is concerned, the
157 variable should still have type 'SomeType', as originally declared.
159 The following function dives into the __Block_byref_x_VarName
160 struct to find the original type of the variable. This will be
161 passed back to the code generating the type for the Debug
162 Information Entry for the variable 'VarName'. 'VarName' will then
163 have the original type 'SomeType' in its debug information.
165 The original type 'SomeType' will be the type of the field named
166 'VarName' inside the __Block_byref_x_VarName struct.
168 NOTE: In order for this to not completely fail on the debugger
169 side, the Debug Information Entry for the variable VarName needs to
170 have a DW_AT_location that tells the debugger how to unwind through
171 the pointers and __Block_byref_x_VarName struct to find the actual
172 value of the variable. The function addBlockByrefType does this. */
173 DIType *subType = Ty;
174 uint16_t tag = Ty->getTag();
176 if (tag == dwarf::DW_TAG_pointer_type)
177 subType = resolve(cast<DIDerivedType>(Ty)->getBaseType());
179 auto Elements = cast<DICompositeTypeBase>(subType)->getElements();
180 for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
181 auto *DT = cast<DIDerivedTypeBase>(Elements[i]);
182 if (getName() == DT->getName())
183 return resolve(DT->getBaseType());
189 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
190 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
191 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
192 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
194 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
195 : Asm(A), MMI(Asm->MMI), DebugLocs(A->OutStreamer->isVerboseAsm()),
196 PrevLabel(nullptr), InfoHolder(A, "info_string", DIEValueAllocator),
197 UsedNonDefaultText(false),
198 SkeletonHolder(A, "skel_string", DIEValueAllocator),
199 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
200 IsPS4(Triple(A->getTargetTriple()).isPS4()),
201 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
202 dwarf::DW_FORM_data4)),
203 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
204 dwarf::DW_FORM_data4)),
205 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
206 dwarf::DW_FORM_data4)),
207 AccelTypes(TypeAtoms) {
212 // Turn on accelerator tables for Darwin by default, pubnames by
213 // default for non-Darwin/PS4, and handle split dwarf.
214 if (DwarfAccelTables == Default)
215 HasDwarfAccelTables = IsDarwin;
217 HasDwarfAccelTables = DwarfAccelTables == Enable;
219 if (SplitDwarf == Default)
220 HasSplitDwarf = false;
222 HasSplitDwarf = SplitDwarf == Enable;
224 if (DwarfPubSections == Default)
225 HasDwarfPubSections = !IsDarwin && !IsPS4;
227 HasDwarfPubSections = DwarfPubSections == Enable;
229 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
230 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
231 : MMI->getModule()->getDwarfVersion();
233 // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3).
234 // Everybody else uses GNU's.
235 UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3;
237 Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion);
240 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
245 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
246 DwarfDebug::~DwarfDebug() { }
248 static bool isObjCClass(StringRef Name) {
249 return Name.startswith("+") || Name.startswith("-");
252 static bool hasObjCCategory(StringRef Name) {
253 if (!isObjCClass(Name))
256 return Name.find(") ") != StringRef::npos;
259 static void getObjCClassCategory(StringRef In, StringRef &Class,
260 StringRef &Category) {
261 if (!hasObjCCategory(In)) {
262 Class = In.slice(In.find('[') + 1, In.find(' '));
267 Class = In.slice(In.find('[') + 1, In.find('('));
268 Category = In.slice(In.find('[') + 1, In.find(' '));
272 static StringRef getObjCMethodName(StringRef In) {
273 return In.slice(In.find(' ') + 1, In.find(']'));
276 // Add the various names to the Dwarf accelerator table names.
277 // TODO: Determine whether or not we should add names for programs
278 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
279 // is only slightly different than the lookup of non-standard ObjC names.
280 void DwarfDebug::addSubprogramNames(const DISubprogram *SP, DIE &Die) {
281 if (!SP->isDefinition())
283 addAccelName(SP->getName(), Die);
285 // If the linkage name is different than the name, go ahead and output
286 // that as well into the name table.
287 if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName())
288 addAccelName(SP->getLinkageName(), Die);
290 // If this is an Objective-C selector name add it to the ObjC accelerator
292 if (isObjCClass(SP->getName())) {
293 StringRef Class, Category;
294 getObjCClassCategory(SP->getName(), Class, Category);
295 addAccelObjC(Class, Die);
297 addAccelObjC(Category, Die);
298 // Also add the base method name to the name table.
299 addAccelName(getObjCMethodName(SP->getName()), Die);
303 /// isSubprogramContext - Return true if Context is either a subprogram
304 /// or another context nested inside a subprogram.
305 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
308 if (isa<DISubprogram>(Context))
310 if (auto *T = dyn_cast<DIType>(Context))
311 return isSubprogramContext(resolve(T->getScope()));
315 /// Check whether we should create a DIE for the given Scope, return true
316 /// if we don't create a DIE (the corresponding DIE is null).
317 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
318 if (Scope->isAbstractScope())
321 // We don't create a DIE if there is no Range.
322 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
326 if (Ranges.size() > 1)
329 // We don't create a DIE if we have a single Range and the end label
331 return !getLabelAfterInsn(Ranges.front().second);
334 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
336 if (auto *SkelCU = CU.getSkeleton())
340 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
341 assert(Scope && Scope->getScopeNode());
342 assert(Scope->isAbstractScope());
343 assert(!Scope->getInlinedAt());
345 const MDNode *SP = Scope->getScopeNode();
347 ProcessedSPNodes.insert(SP);
349 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
350 // was inlined from another compile unit.
351 auto &CU = SPMap[SP];
352 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
353 CU.constructAbstractSubprogramScopeDIE(Scope);
357 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
358 if (!GenerateGnuPubSections)
361 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
364 // Create new DwarfCompileUnit for the given metadata node with tag
365 // DW_TAG_compile_unit.
367 DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) {
368 StringRef FN = DIUnit->getFilename();
369 CompilationDir = DIUnit->getDirectory();
371 auto OwnedUnit = make_unique<DwarfCompileUnit>(
372 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
373 DwarfCompileUnit &NewCU = *OwnedUnit;
374 DIE &Die = NewCU.getUnitDie();
375 InfoHolder.addUnit(std::move(OwnedUnit));
377 NewCU.setSkeleton(constructSkeletonCU(NewCU));
379 // LTO with assembly output shares a single line table amongst multiple CUs.
380 // To avoid the compilation directory being ambiguous, let the line table
381 // explicitly describe the directory of all files, never relying on the
382 // compilation directory.
383 if (!Asm->OutStreamer->hasRawTextSupport() || SingleCU)
384 Asm->OutStreamer->getContext().setMCLineTableCompilationDir(
385 NewCU.getUniqueID(), CompilationDir);
387 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer());
388 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
389 DIUnit->getSourceLanguage());
390 NewCU.addString(Die, dwarf::DW_AT_name, FN);
392 if (!useSplitDwarf()) {
393 NewCU.initStmtList();
395 // If we're using split dwarf the compilation dir is going to be in the
396 // skeleton CU and so we don't need to duplicate it here.
397 if (!CompilationDir.empty())
398 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
400 addGnuPubAttributes(NewCU, Die);
403 if (DIUnit->isOptimized())
404 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
406 StringRef Flags = DIUnit->getFlags();
408 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
410 if (unsigned RVer = DIUnit->getRuntimeVersion())
411 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
412 dwarf::DW_FORM_data1, RVer);
415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
417 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
419 CUMap.insert(std::make_pair(DIUnit, &NewCU));
420 CUDieMap.insert(std::make_pair(&Die, &NewCU));
424 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
425 const DIImportedEntity *N) {
426 if (DIE *D = TheCU.getOrCreateContextDIE(N->getScope()))
427 D->addChild(TheCU.constructImportedEntityDIE(N));
430 // Emit all Dwarf sections that should come prior to the content. Create
431 // global DIEs and emit initial debug info sections. This is invoked by
432 // the target AsmPrinter.
433 void DwarfDebug::beginModule() {
434 if (DisableDebugInfoPrinting)
437 const Module *M = MMI->getModule();
439 FunctionDIs = makeSubprogramMap(*M);
441 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
444 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
446 SingleCU = CU_Nodes->getNumOperands() == 1;
448 for (MDNode *N : CU_Nodes->operands()) {
449 auto *CUNode = cast<DICompileUnit>(N);
450 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
451 for (auto *IE : CUNode->getImportedEntities())
452 ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE));
453 // Stable sort to preserve the order of appearance of imported entities.
454 // This is to avoid out-of-order processing of interdependent declarations
455 // within the same scope, e.g. { namespace A = base; namespace B = A; }
456 std::stable_sort(ScopesWithImportedEntities.begin(),
457 ScopesWithImportedEntities.end(), less_first());
458 for (auto *GV : CUNode->getGlobalVariables())
459 CU.getOrCreateGlobalVariableDIE(GV);
460 for (auto *SP : CUNode->getSubprograms())
461 SPMap.insert(std::make_pair(SP, &CU));
462 for (auto *Ty : CUNode->getEnumTypes()) {
463 // The enum types array by design contains pointers to
464 // MDNodes rather than DIRefs. Unique them here.
465 CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef())));
467 for (auto *Ty : CUNode->getRetainedTypes()) {
468 // The retained types array by design contains pointers to
469 // MDNodes rather than DIRefs. Unique them here.
470 DIType *RT = cast<DIType>(resolve(Ty->getRef()));
471 if (!RT->isExternalTypeRef())
472 // There is no point in force-emitting a forward declaration.
473 CU.getOrCreateTypeDIE(RT);
475 // Emit imported_modules last so that the relevant context is already
477 for (auto *IE : CUNode->getImportedEntities())
478 constructAndAddImportedEntityDIE(CU, IE);
481 // Tell MMI that we have debug info.
482 MMI->setDebugInfoAvailability(true);
485 void DwarfDebug::finishVariableDefinitions() {
486 for (const auto &Var : ConcreteVariables) {
487 DIE *VariableDie = Var->getDIE();
489 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
490 // in the ConcreteVariables list, rather than looking it up again here.
491 // DIE::getUnit isn't simple - it walks parent pointers, etc.
492 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
494 DbgVariable *AbsVar = getExistingAbstractVariable(
495 InlinedVariable(Var->getVariable(), Var->getInlinedAt()));
496 if (AbsVar && AbsVar->getDIE()) {
497 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
500 Unit->applyVariableAttributes(*Var, *VariableDie);
504 void DwarfDebug::finishSubprogramDefinitions() {
505 for (const auto &P : SPMap)
506 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
507 CU.finishSubprogramDefinition(cast<DISubprogram>(P.first));
512 // Collect info for variables that were optimized out.
513 void DwarfDebug::collectDeadVariables() {
514 const Module *M = MMI->getModule();
516 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
517 for (MDNode *N : CU_Nodes->operands()) {
518 auto *TheCU = cast<DICompileUnit>(N);
519 // Construct subprogram DIE and add variables DIEs.
520 DwarfCompileUnit *SPCU =
521 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
522 assert(SPCU && "Unable to find Compile Unit!");
523 for (auto *SP : TheCU->getSubprograms()) {
524 if (ProcessedSPNodes.count(SP) != 0)
526 SPCU->collectDeadVariables(SP);
532 void DwarfDebug::finalizeModuleInfo() {
533 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
535 finishSubprogramDefinitions();
537 finishVariableDefinitions();
539 // Collect info for variables that were optimized out.
540 collectDeadVariables();
542 // Handle anything that needs to be done on a per-unit basis after
543 // all other generation.
544 for (const auto &P : CUMap) {
545 auto &TheCU = *P.second;
546 // Emit DW_AT_containing_type attribute to connect types with their
547 // vtable holding type.
548 TheCU.constructContainingTypeDIEs();
550 // Add CU specific attributes if we need to add any.
551 // If we're splitting the dwarf out now that we've got the entire
552 // CU then add the dwo id to it.
553 auto *SkCU = TheCU.getSkeleton();
554 if (useSplitDwarf()) {
555 // Emit a unique identifier for this CU.
556 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
557 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
558 dwarf::DW_FORM_data8, ID);
559 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
560 dwarf::DW_FORM_data8, ID);
562 // We don't keep track of which addresses are used in which CU so this
563 // is a bit pessimistic under LTO.
564 if (!AddrPool.isEmpty()) {
565 const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol();
566 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
569 if (!SkCU->getRangeLists().empty()) {
570 const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol();
571 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
576 // If we have code split among multiple sections or non-contiguous
577 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
578 // remain in the .o file, otherwise add a DW_AT_low_pc.
579 // FIXME: We should use ranges allow reordering of code ala
580 // .subsections_via_symbols in mach-o. This would mean turning on
581 // ranges for all subprogram DIEs for mach-o.
582 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
583 if (unsigned NumRanges = TheCU.getRanges().size()) {
585 // A DW_AT_low_pc attribute may also be specified in combination with
586 // DW_AT_ranges to specify the default base address for use in
587 // location lists (see Section 2.6.2) and range lists (see Section
589 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
591 U.setBaseAddress(TheCU.getRanges().front().getStart());
592 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
596 // Compute DIE offsets and sizes.
597 InfoHolder.computeSizeAndOffsets();
599 SkeletonHolder.computeSizeAndOffsets();
602 // Emit all Dwarf sections that should come after the content.
603 void DwarfDebug::endModule() {
604 assert(CurFn == nullptr);
605 assert(CurMI == nullptr);
607 // If we aren't actually generating debug info (check beginModule -
608 // conditionalized on !DisableDebugInfoPrinting and the presence of the
609 // llvm.dbg.cu metadata node)
610 if (!MMI->hasDebugInfo())
613 // Finalize the debug info for the module.
614 finalizeModuleInfo();
621 // Emit info into a debug loc section.
624 // Corresponding abbreviations into a abbrev section.
627 // Emit all the DIEs into a debug info section.
630 // Emit info into a debug aranges section.
631 if (GenerateARangeSection)
634 // Emit info into a debug ranges section.
637 if (useSplitDwarf()) {
640 emitDebugAbbrevDWO();
642 // Emit DWO addresses.
643 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
646 // Emit info into the dwarf accelerator table sections.
647 if (useDwarfAccelTables()) {
650 emitAccelNamespaces();
654 // Emit the pubnames and pubtypes sections if requested.
655 if (HasDwarfPubSections) {
656 emitDebugPubNames(GenerateGnuPubSections);
657 emitDebugPubTypes(GenerateGnuPubSections);
662 AbstractVariables.clear();
665 // Find abstract variable, if any, associated with Var.
667 DwarfDebug::getExistingAbstractVariable(InlinedVariable IV,
668 const DILocalVariable *&Cleansed) {
669 // More then one inlined variable corresponds to one abstract variable.
671 auto I = AbstractVariables.find(Cleansed);
672 if (I != AbstractVariables.end())
673 return I->second.get();
677 DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV) {
678 const DILocalVariable *Cleansed;
679 return getExistingAbstractVariable(IV, Cleansed);
682 void DwarfDebug::createAbstractVariable(const DILocalVariable *Var,
683 LexicalScope *Scope) {
684 auto AbsDbgVariable = make_unique<DbgVariable>(Var, /* IA */ nullptr, this);
685 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
686 AbstractVariables[Var] = std::move(AbsDbgVariable);
689 void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV,
690 const MDNode *ScopeNode) {
691 const DILocalVariable *Cleansed = nullptr;
692 if (getExistingAbstractVariable(IV, Cleansed))
695 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(
696 cast<DILocalScope>(ScopeNode)));
699 void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(
700 InlinedVariable IV, const MDNode *ScopeNode) {
701 const DILocalVariable *Cleansed = nullptr;
702 if (getExistingAbstractVariable(IV, Cleansed))
705 if (LexicalScope *Scope =
706 LScopes.findAbstractScope(cast_or_null<DILocalScope>(ScopeNode)))
707 createAbstractVariable(Cleansed, Scope);
710 // Collect variable information from side table maintained by MMI.
711 void DwarfDebug::collectVariableInfoFromMMITable(
712 DenseSet<InlinedVariable> &Processed) {
713 for (const auto &VI : MMI->getVariableDbgInfo()) {
716 assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
717 "Expected inlined-at fields to agree");
719 InlinedVariable Var(VI.Var, VI.Loc->getInlinedAt());
720 Processed.insert(Var);
721 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
723 // If variable scope is not found then skip this variable.
727 ensureAbstractVariableIsCreatedIfScoped(Var, Scope->getScopeNode());
728 auto RegVar = make_unique<DbgVariable>(Var.first, Var.second, this);
729 RegVar->initializeMMI(VI.Expr, VI.Slot);
730 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
731 ConcreteVariables.push_back(std::move(RegVar));
735 // Get .debug_loc entry for the instruction range starting at MI.
736 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
737 const DIExpression *Expr = MI->getDebugExpression();
739 assert(MI->getNumOperands() == 4);
740 if (MI->getOperand(0).isReg()) {
741 MachineLocation MLoc;
742 // If the second operand is an immediate, this is a
743 // register-indirect address.
744 if (!MI->getOperand(1).isImm())
745 MLoc.set(MI->getOperand(0).getReg());
747 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
748 return DebugLocEntry::Value(Expr, MLoc);
750 if (MI->getOperand(0).isImm())
751 return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm());
752 if (MI->getOperand(0).isFPImm())
753 return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm());
754 if (MI->getOperand(0).isCImm())
755 return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm());
757 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
760 /// Determine whether two variable pieces overlap.
761 static bool piecesOverlap(const DIExpression *P1, const DIExpression *P2) {
762 if (!P1->isBitPiece() || !P2->isBitPiece())
764 unsigned l1 = P1->getBitPieceOffset();
765 unsigned l2 = P2->getBitPieceOffset();
766 unsigned r1 = l1 + P1->getBitPieceSize();
767 unsigned r2 = l2 + P2->getBitPieceSize();
768 // True where [l1,r1[ and [r1,r2[ overlap.
769 return (l1 < r2) && (l2 < r1);
772 /// Build the location list for all DBG_VALUEs in the function that
773 /// describe the same variable. If the ranges of several independent
774 /// pieces of the same variable overlap partially, split them up and
775 /// combine the ranges. The resulting DebugLocEntries are will have
776 /// strict monotonically increasing begin addresses and will never
781 // Ranges History [var, loc, piece ofs size]
782 // 0 | [x, (reg0, piece 0, 32)]
783 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
785 // 3 | [clobber reg0]
786 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
791 // [0-1] [x, (reg0, piece 0, 32)]
792 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
793 // [3-4] [x, (reg1, piece 32, 32)]
794 // [4- ] [x, (mem, piece 0, 64)]
796 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
797 const DbgValueHistoryMap::InstrRanges &Ranges) {
798 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
800 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
801 const MachineInstr *Begin = I->first;
802 const MachineInstr *End = I->second;
803 assert(Begin->isDebugValue() && "Invalid History entry");
805 // Check if a variable is inaccessible in this range.
806 if (Begin->getNumOperands() > 1 &&
807 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
812 // If this piece overlaps with any open ranges, truncate them.
813 const DIExpression *DIExpr = Begin->getDebugExpression();
814 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
815 [&](DebugLocEntry::Value R) {
816 return piecesOverlap(DIExpr, R.getExpression());
818 OpenRanges.erase(Last, OpenRanges.end());
820 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
821 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
823 const MCSymbol *EndLabel;
825 EndLabel = getLabelAfterInsn(End);
826 else if (std::next(I) == Ranges.end())
827 EndLabel = Asm->getFunctionEnd();
829 EndLabel = getLabelBeforeInsn(std::next(I)->first);
830 assert(EndLabel && "Forgot label after instruction ending a range!");
832 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
834 auto Value = getDebugLocValue(Begin);
835 DebugLocEntry Loc(StartLabel, EndLabel, Value);
836 bool couldMerge = false;
838 // If this is a piece, it may belong to the current DebugLocEntry.
839 if (DIExpr->isBitPiece()) {
840 // Add this value to the list of open ranges.
841 OpenRanges.push_back(Value);
843 // Attempt to add the piece to the last entry.
844 if (!DebugLoc.empty())
845 if (DebugLoc.back().MergeValues(Loc))
850 // Need to add a new DebugLocEntry. Add all values from still
851 // valid non-overlapping pieces.
852 if (OpenRanges.size())
853 Loc.addValues(OpenRanges);
855 DebugLoc.push_back(std::move(Loc));
858 // Attempt to coalesce the ranges of two otherwise identical
860 auto CurEntry = DebugLoc.rbegin();
862 dbgs() << CurEntry->getValues().size() << " Values:\n";
863 for (auto &Value : CurEntry->getValues())
864 Value.getExpression()->dump();
868 auto PrevEntry = std::next(CurEntry);
869 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
874 DbgVariable *DwarfDebug::createConcreteVariable(LexicalScope &Scope,
875 InlinedVariable IV) {
876 ensureAbstractVariableIsCreatedIfScoped(IV, Scope.getScopeNode());
877 ConcreteVariables.push_back(
878 make_unique<DbgVariable>(IV.first, IV.second, this));
879 InfoHolder.addScopeVariable(&Scope, ConcreteVariables.back().get());
880 return ConcreteVariables.back().get();
883 // Find variables for each lexical scope.
884 void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU,
885 const DISubprogram *SP,
886 DenseSet<InlinedVariable> &Processed) {
887 // Grab the variable info that was squirreled away in the MMI side-table.
888 collectVariableInfoFromMMITable(Processed);
890 for (const auto &I : DbgValues) {
891 InlinedVariable IV = I.first;
892 if (Processed.count(IV))
895 // Instruction ranges, specifying where IV is accessible.
896 const auto &Ranges = I.second;
900 LexicalScope *Scope = nullptr;
901 if (const DILocation *IA = IV.second)
902 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA);
904 Scope = LScopes.findLexicalScope(IV.first->getScope());
905 // If variable scope is not found then skip this variable.
909 Processed.insert(IV);
910 DbgVariable *RegVar = createConcreteVariable(*Scope, IV);
912 const MachineInstr *MInsn = Ranges.front().first;
913 assert(MInsn->isDebugValue() && "History must begin with debug value");
915 // Check if the first DBG_VALUE is valid for the rest of the function.
916 if (Ranges.size() == 1 && Ranges.front().second == nullptr) {
917 RegVar->initializeDbgValue(MInsn);
921 // Handle multiple DBG_VALUE instructions describing one variable.
922 DebugLocStream::ListBuilder List(DebugLocs, TheCU, *Asm, *RegVar, *MInsn);
924 // Build the location list for this variable.
925 SmallVector<DebugLocEntry, 8> Entries;
926 buildLocationList(Entries, Ranges);
928 // If the variable has an DIBasicType, extract it. Basic types cannot have
929 // unique identifiers, so don't bother resolving the type with the
931 const DIBasicType *BT = dyn_cast<DIBasicType>(
932 static_cast<const Metadata *>(IV.first->getType()));
934 // Finalize the entry by lowering it into a DWARF bytestream.
935 for (auto &Entry : Entries)
936 Entry.finalize(*Asm, List, BT);
939 // Collect info for variables that were optimized out.
940 for (const DILocalVariable *DV : SP->getVariables()) {
941 if (Processed.insert(InlinedVariable(DV, nullptr)).second)
942 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope()))
943 createConcreteVariable(*Scope, InlinedVariable(DV, nullptr));
947 // Return Label preceding the instruction.
948 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
949 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
950 assert(Label && "Didn't insert label before instruction");
954 // Return Label immediately following the instruction.
955 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
956 return LabelsAfterInsn.lookup(MI);
959 // Process beginning of an instruction.
960 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
961 assert(CurMI == nullptr);
963 // Check if source location changes, but ignore DBG_VALUE locations.
964 if (!MI->isDebugValue()) {
965 DebugLoc DL = MI->getDebugLoc();
966 if (DL != PrevInstLoc) {
970 if (DL == PrologEndLoc) {
971 Flags |= DWARF2_FLAG_PROLOGUE_END;
972 PrologEndLoc = DebugLoc();
973 Flags |= DWARF2_FLAG_IS_STMT;
976 Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine())
977 Flags |= DWARF2_FLAG_IS_STMT;
979 const MDNode *Scope = DL.getScope();
980 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
981 } else if (UnknownLocations) {
983 recordSourceLine(0, 0, nullptr, 0);
988 // Insert labels where requested.
989 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
990 LabelsBeforeInsn.find(MI);
993 if (I == LabelsBeforeInsn.end())
996 // Label already assigned.
1001 PrevLabel = MMI->getContext().createTempSymbol();
1002 Asm->OutStreamer->EmitLabel(PrevLabel);
1004 I->second = PrevLabel;
1007 // Process end of an instruction.
1008 void DwarfDebug::endInstruction() {
1009 assert(CurMI != nullptr);
1010 // Don't create a new label after DBG_VALUE instructions.
1011 // They don't generate code.
1012 if (!CurMI->isDebugValue())
1013 PrevLabel = nullptr;
1015 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1016 LabelsAfterInsn.find(CurMI);
1020 if (I == LabelsAfterInsn.end())
1023 // Label already assigned.
1027 // We need a label after this instruction.
1029 PrevLabel = MMI->getContext().createTempSymbol();
1030 Asm->OutStreamer->EmitLabel(PrevLabel);
1032 I->second = PrevLabel;
1035 // Each LexicalScope has first instruction and last instruction to mark
1036 // beginning and end of a scope respectively. Create an inverse map that list
1037 // scopes starts (and ends) with an instruction. One instruction may start (or
1038 // end) multiple scopes. Ignore scopes that are not reachable.
1039 void DwarfDebug::identifyScopeMarkers() {
1040 SmallVector<LexicalScope *, 4> WorkList;
1041 WorkList.push_back(LScopes.getCurrentFunctionScope());
1042 while (!WorkList.empty()) {
1043 LexicalScope *S = WorkList.pop_back_val();
1045 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1046 if (!Children.empty())
1047 WorkList.append(Children.begin(), Children.end());
1049 if (S->isAbstractScope())
1052 for (const InsnRange &R : S->getRanges()) {
1053 assert(R.first && "InsnRange does not have first instruction!");
1054 assert(R.second && "InsnRange does not have second instruction!");
1055 requestLabelBeforeInsn(R.first);
1056 requestLabelAfterInsn(R.second);
1061 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1062 // First known non-DBG_VALUE and non-frame setup location marks
1063 // the beginning of the function body.
1064 for (const auto &MBB : *MF)
1065 for (const auto &MI : MBB)
1066 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1068 // Did the target forget to set the FrameSetup flag for CFI insns?
1069 assert(!MI.isCFIInstruction() &&
1070 "First non-frame-setup instruction is a CFI instruction.");
1071 return MI.getDebugLoc();
1076 // Gather pre-function debug information. Assumes being called immediately
1077 // after the function entry point has been emitted.
1078 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1081 // If there's no debug info for the function we're not going to do anything.
1082 if (!MMI->hasDebugInfo())
1085 auto DI = FunctionDIs.find(MF->getFunction());
1086 if (DI == FunctionDIs.end())
1089 // Grab the lexical scopes for the function, if we don't have any of those
1090 // then we're not going to be able to do anything.
1091 LScopes.initialize(*MF);
1092 if (LScopes.empty())
1095 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1097 // Make sure that each lexical scope will have a begin/end label.
1098 identifyScopeMarkers();
1100 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1101 // belongs to so that we add to the correct per-cu line table in the
1103 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1104 // FnScope->getScopeNode() and DI->second should represent the same function,
1105 // though they may not be the same MDNode due to inline functions merged in
1106 // LTO where the debug info metadata still differs (either due to distinct
1107 // written differences - two versions of a linkonce_odr function
1108 // written/copied into two separate files, or some sub-optimal metadata that
1109 // isn't structurally identical (see: file path/name info from clang, which
1110 // includes the directory of the cpp file being built, even when the file name
1111 // is absolute (such as an <> lookup header)))
1112 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1113 assert(TheCU && "Unable to find compile unit!");
1114 if (Asm->OutStreamer->hasRawTextSupport())
1115 // Use a single line table if we are generating assembly.
1116 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
1118 Asm->OutStreamer->getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1120 // Calculate history for local variables.
1121 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1124 // Request labels for the full history.
1125 for (const auto &I : DbgValues) {
1126 const auto &Ranges = I.second;
1130 // The first mention of a function argument gets the CurrentFnBegin
1131 // label, so arguments are visible when breaking at function entry.
1132 const DILocalVariable *DIVar = Ranges.front().first->getDebugVariable();
1133 if (DIVar->getTag() == dwarf::DW_TAG_arg_variable &&
1134 getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) {
1135 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin();
1136 if (Ranges.front().first->getDebugExpression()->isBitPiece()) {
1137 // Mark all non-overlapping initial pieces.
1138 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1139 const DIExpression *Piece = I->first->getDebugExpression();
1140 if (std::all_of(Ranges.begin(), I,
1141 [&](DbgValueHistoryMap::InstrRange Pred) {
1142 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1144 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
1151 for (const auto &Range : Ranges) {
1152 requestLabelBeforeInsn(Range.first);
1154 requestLabelAfterInsn(Range.second);
1158 PrevInstLoc = DebugLoc();
1159 PrevLabel = Asm->getFunctionBegin();
1161 // Record beginning of function.
1162 PrologEndLoc = findPrologueEndLoc(MF);
1163 if (DILocation *L = PrologEndLoc) {
1164 // We'd like to list the prologue as "not statements" but GDB behaves
1165 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1166 auto *SP = L->getInlinedAtScope()->getSubprogram();
1167 recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT);
1171 // Gather and emit post-function debug information.
1172 void DwarfDebug::endFunction(const MachineFunction *MF) {
1173 assert(CurFn == MF &&
1174 "endFunction should be called with the same function as beginFunction");
1176 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1177 !FunctionDIs.count(MF->getFunction())) {
1178 // If we don't have a lexical scope for this function then there will
1179 // be a hole in the range information. Keep note of this by setting the
1180 // previously used section to nullptr.
1186 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1187 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
1189 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1190 auto *SP = cast<DISubprogram>(FnScope->getScopeNode());
1191 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1193 DenseSet<InlinedVariable> ProcessedVars;
1194 collectVariableInfo(TheCU, SP, ProcessedVars);
1196 // Add the range of this function to the list of ranges for the CU.
1197 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd()));
1199 // Under -gmlt, skip building the subprogram if there are no inlined
1200 // subroutines inside it.
1201 if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly &&
1202 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1203 assert(InfoHolder.getScopeVariables().empty());
1204 assert(DbgValues.empty());
1205 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1206 // by a -gmlt CU. Add a test and remove this assertion.
1207 assert(AbstractVariables.empty());
1208 LabelsBeforeInsn.clear();
1209 LabelsAfterInsn.clear();
1210 PrevLabel = nullptr;
1216 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1218 // Construct abstract scopes.
1219 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1220 auto *SP = cast<DISubprogram>(AScope->getScopeNode());
1221 // Collect info for variables that were optimized out.
1222 for (const DILocalVariable *DV : SP->getVariables()) {
1223 if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second)
1225 ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr),
1227 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1228 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1230 constructAbstractSubprogramScopeDIE(AScope);
1233 TheCU.constructSubprogramScopeDIE(FnScope);
1234 if (auto *SkelCU = TheCU.getSkeleton())
1235 if (!LScopes.getAbstractScopesList().empty())
1236 SkelCU->constructSubprogramScopeDIE(FnScope);
1239 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1240 // DbgVariables except those that are also in AbstractVariables (since they
1241 // can be used cross-function)
1242 InfoHolder.getScopeVariables().clear();
1244 LabelsBeforeInsn.clear();
1245 LabelsAfterInsn.clear();
1246 PrevLabel = nullptr;
1250 // Register a source line with debug info. Returns the unique label that was
1251 // emitted and which provides correspondence to the source line list.
1252 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1257 unsigned Discriminator = 0;
1258 if (auto *Scope = cast_or_null<DIScope>(S)) {
1259 Fn = Scope->getFilename();
1260 Dir = Scope->getDirectory();
1261 if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
1262 Discriminator = LBF->getDiscriminator();
1264 unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();
1265 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1266 .getOrCreateSourceID(Fn, Dir);
1268 Asm->OutStreamer->EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1272 //===----------------------------------------------------------------------===//
1274 //===----------------------------------------------------------------------===//
1276 // Emit the debug info section.
1277 void DwarfDebug::emitDebugInfo() {
1278 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1279 Holder.emitUnits(/* UseOffsets */ false);
1282 // Emit the abbreviation section.
1283 void DwarfDebug::emitAbbreviations() {
1284 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1286 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1289 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, MCSection *Section,
1290 StringRef TableName) {
1291 Accel.FinalizeTable(Asm, TableName);
1292 Asm->OutStreamer->SwitchSection(Section);
1294 // Emit the full data.
1295 Accel.emit(Asm, Section->getBeginSymbol(), this);
1298 // Emit visible names into a hashed accelerator table section.
1299 void DwarfDebug::emitAccelNames() {
1300 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1304 // Emit objective C classes and categories into a hashed accelerator table
1306 void DwarfDebug::emitAccelObjC() {
1307 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1311 // Emit namespace dies into a hashed accelerator table.
1312 void DwarfDebug::emitAccelNamespaces() {
1313 emitAccel(AccelNamespace,
1314 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1318 // Emit type dies into a hashed accelerator table.
1319 void DwarfDebug::emitAccelTypes() {
1320 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1324 // Public name handling.
1325 // The format for the various pubnames:
1327 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1328 // for the DIE that is named.
1330 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1331 // into the CU and the index value is computed according to the type of value
1332 // for the DIE that is named.
1334 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1335 // it's the offset within the debug_info/debug_types dwo section, however, the
1336 // reference in the pubname header doesn't change.
1338 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1339 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1341 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1343 // We could have a specification DIE that has our most of our knowledge,
1344 // look for that now.
1345 if (DIEValue SpecVal = Die->findAttribute(dwarf::DW_AT_specification)) {
1346 DIE &SpecDIE = SpecVal.getDIEEntry().getEntry();
1347 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1348 Linkage = dwarf::GIEL_EXTERNAL;
1349 } else if (Die->findAttribute(dwarf::DW_AT_external))
1350 Linkage = dwarf::GIEL_EXTERNAL;
1352 switch (Die->getTag()) {
1353 case dwarf::DW_TAG_class_type:
1354 case dwarf::DW_TAG_structure_type:
1355 case dwarf::DW_TAG_union_type:
1356 case dwarf::DW_TAG_enumeration_type:
1357 return dwarf::PubIndexEntryDescriptor(
1358 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1359 ? dwarf::GIEL_STATIC
1360 : dwarf::GIEL_EXTERNAL);
1361 case dwarf::DW_TAG_typedef:
1362 case dwarf::DW_TAG_base_type:
1363 case dwarf::DW_TAG_subrange_type:
1364 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1365 case dwarf::DW_TAG_namespace:
1366 return dwarf::GIEK_TYPE;
1367 case dwarf::DW_TAG_subprogram:
1368 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1369 case dwarf::DW_TAG_variable:
1370 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1371 case dwarf::DW_TAG_enumerator:
1372 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1373 dwarf::GIEL_STATIC);
1375 return dwarf::GIEK_NONE;
1379 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1381 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1382 MCSection *PSec = GnuStyle
1383 ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1384 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1386 emitDebugPubSection(GnuStyle, PSec, "Names",
1387 &DwarfCompileUnit::getGlobalNames);
1390 void DwarfDebug::emitDebugPubSection(
1391 bool GnuStyle, MCSection *PSec, StringRef Name,
1392 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1393 for (const auto &NU : CUMap) {
1394 DwarfCompileUnit *TheU = NU.second;
1396 const auto &Globals = (TheU->*Accessor)();
1398 if (Globals.empty())
1401 if (auto *Skeleton = TheU->getSkeleton())
1404 // Start the dwarf pubnames section.
1405 Asm->OutStreamer->SwitchSection(PSec);
1408 Asm->OutStreamer->AddComment("Length of Public " + Name + " Info");
1409 MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin");
1410 MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end");
1411 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1413 Asm->OutStreamer->EmitLabel(BeginLabel);
1415 Asm->OutStreamer->AddComment("DWARF Version");
1416 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1418 Asm->OutStreamer->AddComment("Offset of Compilation Unit Info");
1419 Asm->emitDwarfSymbolReference(TheU->getLabelBegin());
1421 Asm->OutStreamer->AddComment("Compilation Unit Length");
1422 Asm->EmitInt32(TheU->getLength());
1424 // Emit the pubnames for this compilation unit.
1425 for (const auto &GI : Globals) {
1426 const char *Name = GI.getKeyData();
1427 const DIE *Entity = GI.second;
1429 Asm->OutStreamer->AddComment("DIE offset");
1430 Asm->EmitInt32(Entity->getOffset());
1433 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1434 Asm->OutStreamer->AddComment(
1435 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1436 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1437 Asm->EmitInt8(Desc.toBits());
1440 Asm->OutStreamer->AddComment("External Name");
1441 Asm->OutStreamer->EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1444 Asm->OutStreamer->AddComment("End Mark");
1446 Asm->OutStreamer->EmitLabel(EndLabel);
1450 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1451 MCSection *PSec = GnuStyle
1452 ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1453 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1455 emitDebugPubSection(GnuStyle, PSec, "Types",
1456 &DwarfCompileUnit::getGlobalTypes);
1459 // Emit visible names into a debug str section.
1460 void DwarfDebug::emitDebugStr() {
1461 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1462 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1465 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1466 const DebugLocStream::Entry &Entry) {
1467 auto &&Comments = DebugLocs.getComments(Entry);
1468 auto Comment = Comments.begin();
1469 auto End = Comments.end();
1470 for (uint8_t Byte : DebugLocs.getBytes(Entry))
1471 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1474 static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
1475 ByteStreamer &Streamer,
1476 const DebugLocEntry::Value &Value,
1477 unsigned PieceOffsetInBits) {
1478 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(),
1479 AP.getDwarfDebug()->getDwarfVersion(),
1482 if (Value.isInt()) {
1483 if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed ||
1484 BT->getEncoding() == dwarf::DW_ATE_signed_char))
1485 DwarfExpr.AddSignedConstant(Value.getInt());
1487 DwarfExpr.AddUnsignedConstant(Value.getInt());
1488 } else if (Value.isLocation()) {
1489 MachineLocation Loc = Value.getLoc();
1490 const DIExpression *Expr = Value.getExpression();
1491 if (!Expr || !Expr->getNumElements())
1493 AP.EmitDwarfRegOp(Streamer, Loc);
1495 // Complex address entry.
1496 if (Loc.getOffset()) {
1497 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1498 DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(),
1501 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1505 // else ... ignore constant fp. There is not any good way to
1506 // to represent them here in dwarf.
1510 void DebugLocEntry::finalize(const AsmPrinter &AP,
1511 DebugLocStream::ListBuilder &List,
1512 const DIBasicType *BT) {
1513 DebugLocStream::EntryBuilder Entry(List, Begin, End);
1514 BufferByteStreamer Streamer = Entry.getStreamer();
1515 const DebugLocEntry::Value &Value = Values[0];
1516 if (Value.isBitPiece()) {
1517 // Emit all pieces that belong to the same variable and range.
1518 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1519 return P.isBitPiece();
1520 }) && "all values are expected to be pieces");
1521 assert(std::is_sorted(Values.begin(), Values.end()) &&
1522 "pieces are expected to be sorted");
1524 unsigned Offset = 0;
1525 for (auto Piece : Values) {
1526 const DIExpression *Expr = Piece.getExpression();
1527 unsigned PieceOffset = Expr->getBitPieceOffset();
1528 unsigned PieceSize = Expr->getBitPieceSize();
1529 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1530 if (Offset < PieceOffset) {
1531 // The DWARF spec seriously mandates pieces with no locations for gaps.
1532 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(),
1533 AP.getDwarfDebug()->getDwarfVersion(),
1535 Expr.AddOpPiece(PieceOffset-Offset, 0);
1536 Offset += PieceOffset-Offset;
1538 Offset += PieceSize;
1540 emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset);
1543 assert(Values.size() == 1 && "only pieces may have >1 value");
1544 emitDebugLocValue(AP, BT, Streamer, Value, 0);
1548 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) {
1550 Asm->OutStreamer->AddComment("Loc expr size");
1551 Asm->EmitInt16(DebugLocs.getBytes(Entry).size());
1554 APByteStreamer Streamer(*Asm);
1555 emitDebugLocEntry(Streamer, Entry);
1558 // Emit locations into the debug loc section.
1559 void DwarfDebug::emitDebugLoc() {
1560 // Start the dwarf loc section.
1561 Asm->OutStreamer->SwitchSection(
1562 Asm->getObjFileLowering().getDwarfLocSection());
1563 unsigned char Size = Asm->getDataLayout().getPointerSize();
1564 for (const auto &List : DebugLocs.getLists()) {
1565 Asm->OutStreamer->EmitLabel(List.Label);
1566 const DwarfCompileUnit *CU = List.CU;
1567 for (const auto &Entry : DebugLocs.getEntries(List)) {
1568 // Set up the range. This range is relative to the entry point of the
1569 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1570 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1571 if (auto *Base = CU->getBaseAddress()) {
1572 Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
1573 Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
1575 Asm->OutStreamer->EmitSymbolValue(Entry.BeginSym, Size);
1576 Asm->OutStreamer->EmitSymbolValue(Entry.EndSym, Size);
1579 emitDebugLocEntryLocation(Entry);
1581 Asm->OutStreamer->EmitIntValue(0, Size);
1582 Asm->OutStreamer->EmitIntValue(0, Size);
1586 void DwarfDebug::emitDebugLocDWO() {
1587 Asm->OutStreamer->SwitchSection(
1588 Asm->getObjFileLowering().getDwarfLocDWOSection());
1589 for (const auto &List : DebugLocs.getLists()) {
1590 Asm->OutStreamer->EmitLabel(List.Label);
1591 for (const auto &Entry : DebugLocs.getEntries(List)) {
1592 // Just always use start_length for now - at least that's one address
1593 // rather than two. We could get fancier and try to, say, reuse an
1594 // address we know we've emitted elsewhere (the start of the function?
1595 // The start of the CU or CU subrange that encloses this range?)
1596 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1597 unsigned idx = AddrPool.getIndex(Entry.BeginSym);
1598 Asm->EmitULEB128(idx);
1599 Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4);
1601 emitDebugLocEntryLocation(Entry);
1603 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1608 const MCSymbol *Start, *End;
1611 // Emit a debug aranges section, containing a CU lookup for any
1612 // address we can tie back to a CU.
1613 void DwarfDebug::emitDebugARanges() {
1614 // Provides a unique id per text section.
1615 MapVector<MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1617 // Filter labels by section.
1618 for (const SymbolCU &SCU : ArangeLabels) {
1619 if (SCU.Sym->isInSection()) {
1620 // Make a note of this symbol and it's section.
1621 MCSection *Section = &SCU.Sym->getSection();
1622 if (!Section->getKind().isMetadata())
1623 SectionMap[Section].push_back(SCU);
1625 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1626 // appear in the output. This sucks as we rely on sections to build
1627 // arange spans. We can do it without, but it's icky.
1628 SectionMap[nullptr].push_back(SCU);
1632 // Add terminating symbols for each section.
1633 for (const auto &I : SectionMap) {
1634 MCSection *Section = I.first;
1635 MCSymbol *Sym = nullptr;
1638 Sym = Asm->OutStreamer->endSection(Section);
1640 // Insert a final terminator.
1641 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1644 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1646 for (auto &I : SectionMap) {
1647 const MCSection *Section = I.first;
1648 SmallVector<SymbolCU, 8> &List = I.second;
1649 if (List.size() < 2)
1652 // If we have no section (e.g. common), just write out
1653 // individual spans for each symbol.
1655 for (const SymbolCU &Cur : List) {
1657 Span.Start = Cur.Sym;
1660 Spans[Cur.CU].push_back(Span);
1665 // Sort the symbols by offset within the section.
1666 std::sort(List.begin(), List.end(),
1667 [&](const SymbolCU &A, const SymbolCU &B) {
1668 unsigned IA = A.Sym ? Asm->OutStreamer->GetSymbolOrder(A.Sym) : 0;
1669 unsigned IB = B.Sym ? Asm->OutStreamer->GetSymbolOrder(B.Sym) : 0;
1671 // Symbols with no order assigned should be placed at the end.
1672 // (e.g. section end labels)
1680 // Build spans between each label.
1681 const MCSymbol *StartSym = List[0].Sym;
1682 for (size_t n = 1, e = List.size(); n < e; n++) {
1683 const SymbolCU &Prev = List[n - 1];
1684 const SymbolCU &Cur = List[n];
1686 // Try and build the longest span we can within the same CU.
1687 if (Cur.CU != Prev.CU) {
1689 Span.Start = StartSym;
1691 Spans[Prev.CU].push_back(Span);
1697 // Start the dwarf aranges section.
1698 Asm->OutStreamer->SwitchSection(
1699 Asm->getObjFileLowering().getDwarfARangesSection());
1701 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1703 // Build a list of CUs used.
1704 std::vector<DwarfCompileUnit *> CUs;
1705 for (const auto &it : Spans) {
1706 DwarfCompileUnit *CU = it.first;
1710 // Sort the CU list (again, to ensure consistent output order).
1711 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1712 return A->getUniqueID() < B->getUniqueID();
1715 // Emit an arange table for each CU we used.
1716 for (DwarfCompileUnit *CU : CUs) {
1717 std::vector<ArangeSpan> &List = Spans[CU];
1719 // Describe the skeleton CU's offset and length, not the dwo file's.
1720 if (auto *Skel = CU->getSkeleton())
1723 // Emit size of content not including length itself.
1724 unsigned ContentSize =
1725 sizeof(int16_t) + // DWARF ARange version number
1726 sizeof(int32_t) + // Offset of CU in the .debug_info section
1727 sizeof(int8_t) + // Pointer Size (in bytes)
1728 sizeof(int8_t); // Segment Size (in bytes)
1730 unsigned TupleSize = PtrSize * 2;
1732 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1734 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1736 ContentSize += Padding;
1737 ContentSize += (List.size() + 1) * TupleSize;
1739 // For each compile unit, write the list of spans it covers.
1740 Asm->OutStreamer->AddComment("Length of ARange Set");
1741 Asm->EmitInt32(ContentSize);
1742 Asm->OutStreamer->AddComment("DWARF Arange version number");
1743 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1744 Asm->OutStreamer->AddComment("Offset Into Debug Info Section");
1745 Asm->emitDwarfSymbolReference(CU->getLabelBegin());
1746 Asm->OutStreamer->AddComment("Address Size (in bytes)");
1747 Asm->EmitInt8(PtrSize);
1748 Asm->OutStreamer->AddComment("Segment Size (in bytes)");
1751 Asm->OutStreamer->EmitFill(Padding, 0xff);
1753 for (const ArangeSpan &Span : List) {
1754 Asm->EmitLabelReference(Span.Start, PtrSize);
1756 // Calculate the size as being from the span start to it's end.
1758 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1760 // For symbols without an end marker (e.g. common), we
1761 // write a single arange entry containing just that one symbol.
1762 uint64_t Size = SymSize[Span.Start];
1766 Asm->OutStreamer->EmitIntValue(Size, PtrSize);
1770 Asm->OutStreamer->AddComment("ARange terminator");
1771 Asm->OutStreamer->EmitIntValue(0, PtrSize);
1772 Asm->OutStreamer->EmitIntValue(0, PtrSize);
1776 // Emit visible names into a debug ranges section.
1777 void DwarfDebug::emitDebugRanges() {
1778 // Start the dwarf ranges section.
1779 Asm->OutStreamer->SwitchSection(
1780 Asm->getObjFileLowering().getDwarfRangesSection());
1782 // Size for our labels.
1783 unsigned char Size = Asm->getDataLayout().getPointerSize();
1785 // Grab the specific ranges for the compile units in the module.
1786 for (const auto &I : CUMap) {
1787 DwarfCompileUnit *TheCU = I.second;
1789 if (auto *Skel = TheCU->getSkeleton())
1792 // Iterate over the misc ranges for the compile units in the module.
1793 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1794 // Emit our symbol so we can find the beginning of the range.
1795 Asm->OutStreamer->EmitLabel(List.getSym());
1797 for (const RangeSpan &Range : List.getRanges()) {
1798 const MCSymbol *Begin = Range.getStart();
1799 const MCSymbol *End = Range.getEnd();
1800 assert(Begin && "Range without a begin symbol?");
1801 assert(End && "Range without an end symbol?");
1802 if (auto *Base = TheCU->getBaseAddress()) {
1803 Asm->EmitLabelDifference(Begin, Base, Size);
1804 Asm->EmitLabelDifference(End, Base, Size);
1806 Asm->OutStreamer->EmitSymbolValue(Begin, Size);
1807 Asm->OutStreamer->EmitSymbolValue(End, Size);
1811 // And terminate the list with two 0 values.
1812 Asm->OutStreamer->EmitIntValue(0, Size);
1813 Asm->OutStreamer->EmitIntValue(0, Size);
1818 // DWARF5 Experimental Separate Dwarf emitters.
1820 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1821 std::unique_ptr<DwarfUnit> NewU) {
1822 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1823 U.getCUNode()->getSplitDebugFilename());
1825 if (!CompilationDir.empty())
1826 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1828 addGnuPubAttributes(*NewU, Die);
1830 SkeletonHolder.addUnit(std::move(NewU));
1833 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1834 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1835 // DW_AT_addr_base, DW_AT_ranges_base.
1836 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1838 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1839 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1840 DwarfCompileUnit &NewCU = *OwnedUnit;
1841 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1843 NewCU.initStmtList();
1845 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1850 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1851 // compile units that would normally be in debug_info.
1852 void DwarfDebug::emitDebugInfoDWO() {
1853 assert(useSplitDwarf() && "No split dwarf debug info?");
1854 // Don't emit relocations into the dwo file.
1855 InfoHolder.emitUnits(/* UseOffsets */ true);
1858 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1859 // abbreviations for the .debug_info.dwo section.
1860 void DwarfDebug::emitDebugAbbrevDWO() {
1861 assert(useSplitDwarf() && "No split dwarf?");
1862 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1865 void DwarfDebug::emitDebugLineDWO() {
1866 assert(useSplitDwarf() && "No split dwarf?");
1867 Asm->OutStreamer->SwitchSection(
1868 Asm->getObjFileLowering().getDwarfLineDWOSection());
1869 SplitTypeUnitFileTable.Emit(*Asm->OutStreamer);
1872 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1873 // string section and is identical in format to traditional .debug_str
1875 void DwarfDebug::emitDebugStrDWO() {
1876 assert(useSplitDwarf() && "No split dwarf?");
1877 MCSection *OffSec = Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1878 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1882 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1883 if (!useSplitDwarf())
1886 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory());
1887 return &SplitTypeUnitFileTable;
1890 uint64_t DwarfDebug::makeTypeSignature(StringRef Identifier) {
1892 Hash.update(Identifier);
1893 // ... take the least significant 8 bytes and return those. Our MD5
1894 // implementation always returns its results in little endian, swap bytes
1896 MD5::MD5Result Result;
1898 return support::endian::read64le(Result + 8);
1901 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1902 StringRef Identifier, DIE &RefDie,
1903 const DICompositeType *CTy) {
1904 // Fast path if we're building some type units and one has already used the
1905 // address pool we know we're going to throw away all this work anyway, so
1906 // don't bother building dependent types.
1907 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1910 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1912 CU.addDIETypeSignature(RefDie, *TU);
1916 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1917 AddrPool.resetUsedFlag();
1919 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1920 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1921 this, &InfoHolder, getDwoLineTable(CU));
1922 DwarfTypeUnit &NewTU = *OwnedUnit;
1923 DIE &UnitDie = NewTU.getUnitDie();
1925 TypeUnitsUnderConstruction.push_back(
1926 std::make_pair(std::move(OwnedUnit), CTy));
1928 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1931 uint64_t Signature = makeTypeSignature(Identifier);
1932 NewTU.setTypeSignature(Signature);
1934 if (useSplitDwarf())
1935 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
1937 CU.applyStmtList(UnitDie);
1939 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
1942 NewTU.setType(NewTU.createTypeDIE(CTy));
1945 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
1946 TypeUnitsUnderConstruction.clear();
1948 // Types referencing entries in the address table cannot be placed in type
1950 if (AddrPool.hasBeenUsed()) {
1952 // Remove all the types built while building this type.
1953 // This is pessimistic as some of these types might not be dependent on
1954 // the type that used an address.
1955 for (const auto &TU : TypeUnitsToAdd)
1956 DwarfTypeUnits.erase(TU.second);
1958 // Construct this type in the CU directly.
1959 // This is inefficient because all the dependent types will be rebuilt
1960 // from scratch, including building them in type units, discovering that
1961 // they depend on addresses, throwing them out and rebuilding them.
1962 CU.constructTypeDIE(RefDie, cast<DICompositeType>(CTy));
1966 // If the type wasn't dependent on fission addresses, finish adding the type
1967 // and all its dependent types.
1968 for (auto &TU : TypeUnitsToAdd)
1969 InfoHolder.addUnit(std::move(TU.first));
1971 CU.addDIETypeSignature(RefDie, NewTU);
1974 // Accelerator table mutators - add each name along with its companion
1975 // DIE to the proper table while ensuring that the name that we're going
1976 // to reference is in the string table. We do this since the names we
1977 // add may not only be identical to the names in the DIE.
1978 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
1979 if (!useDwarfAccelTables())
1981 AccelNames.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1984 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
1985 if (!useDwarfAccelTables())
1987 AccelObjC.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1990 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
1991 if (!useDwarfAccelTables())
1993 AccelNamespace.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1996 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
1997 if (!useDwarfAccelTables())
1999 AccelTypes.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);