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"
16 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.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/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 //===----------------------------------------------------------------------===//
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
151 uint16_t tag = Ty.getTag();
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
173 InfoHolder(A, *this, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
204 HasSplitDwarf = SplitDwarf == Enable;
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
209 HasDwarfPubSections = DwarfPubSections == Enable;
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
224 DwarfDebug::~DwarfDebug() { }
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
247 return Name.find(") ") != StringRef::npos;
250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
267 // Helper for sorting sections into a stable output order.
268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
281 addAccelName(SP.getName(), Die);
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
288 // If this is an Objective-C selector name add it to the ObjC accelerator
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
334 assert(Scope && Scope->getScopeNode());
335 assert(Scope->isAbstractScope());
336 assert(!Scope->getInlinedAt());
338 const MDNode *SP = Scope->getScopeNode();
340 ProcessedSPNodes.insert(SP);
342 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
343 // was inlined from another compile unit.
344 SPMap[SP]->constructAbstractSubprogramScopeDIE(Scope);
347 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
348 if (!GenerateGnuPubSections)
351 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
354 // Create new DwarfCompileUnit for the given metadata node with tag
355 // DW_TAG_compile_unit.
356 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
357 StringRef FN = DIUnit.getFilename();
358 CompilationDir = DIUnit.getDirectory();
360 auto OwnedUnit = make_unique<DwarfCompileUnit>(
361 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
362 DwarfCompileUnit &NewCU = *OwnedUnit;
363 DIE &Die = NewCU.getUnitDie();
364 InfoHolder.addUnit(std::move(OwnedUnit));
366 // LTO with assembly output shares a single line table amongst multiple CUs.
367 // To avoid the compilation directory being ambiguous, let the line table
368 // explicitly describe the directory of all files, never relying on the
369 // compilation directory.
370 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
371 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
372 NewCU.getUniqueID(), CompilationDir);
374 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
375 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
376 DIUnit.getLanguage());
377 NewCU.addString(Die, dwarf::DW_AT_name, FN);
379 if (!useSplitDwarf()) {
380 NewCU.initStmtList(DwarfLineSectionSym);
382 // If we're using split dwarf the compilation dir is going to be in the
383 // skeleton CU and so we don't need to duplicate it here.
384 if (!CompilationDir.empty())
385 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
387 addGnuPubAttributes(NewCU, Die);
390 if (DIUnit.isOptimized())
391 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
393 StringRef Flags = DIUnit.getFlags();
395 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
397 if (unsigned RVer = DIUnit.getRunTimeVersion())
398 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
399 dwarf::DW_FORM_data1, RVer);
401 if (useSplitDwarf()) {
402 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
403 DwarfInfoDWOSectionSym);
404 NewCU.setSkeleton(constructSkeletonCU(NewCU));
406 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
407 DwarfInfoSectionSym);
409 CUMap.insert(std::make_pair(DIUnit, &NewCU));
410 CUDieMap.insert(std::make_pair(&Die, &NewCU));
414 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
416 DIImportedEntity Module(N);
417 assert(Module.Verify());
418 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
419 D->addChild(TheCU.constructImportedEntityDIE(Module));
422 // Emit all Dwarf sections that should come prior to the content. Create
423 // global DIEs and emit initial debug info sections. This is invoked by
424 // the target AsmPrinter.
425 void DwarfDebug::beginModule() {
426 if (DisableDebugInfoPrinting)
429 const Module *M = MMI->getModule();
431 FunctionDIs = makeSubprogramMap(*M);
433 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
436 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
438 // Emit initial sections so we can reference labels later.
441 SingleCU = CU_Nodes->getNumOperands() == 1;
443 for (MDNode *N : CU_Nodes->operands()) {
444 DICompileUnit CUNode(N);
445 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
446 DIArray ImportedEntities = CUNode.getImportedEntities();
447 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
448 ScopesWithImportedEntities.push_back(std::make_pair(
449 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
450 ImportedEntities.getElement(i)));
451 std::sort(ScopesWithImportedEntities.begin(),
452 ScopesWithImportedEntities.end(), less_first());
453 DIArray GVs = CUNode.getGlobalVariables();
454 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
455 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
456 DIArray SPs = CUNode.getSubprograms();
457 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
458 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
459 DIArray EnumTypes = CUNode.getEnumTypes();
460 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
461 DIType Ty(EnumTypes.getElement(i));
462 // The enum types array by design contains pointers to
463 // MDNodes rather than DIRefs. Unique them here.
464 DIType UniqueTy(resolve(Ty.getRef()));
465 CU.getOrCreateTypeDIE(UniqueTy);
467 DIArray RetainedTypes = CUNode.getRetainedTypes();
468 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
469 DIType Ty(RetainedTypes.getElement(i));
470 // The retained types array by design contains pointers to
471 // MDNodes rather than DIRefs. Unique them here.
472 DIType UniqueTy(resolve(Ty.getRef()));
473 CU.getOrCreateTypeDIE(UniqueTy);
475 // Emit imported_modules last so that the relevant context is already
477 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
478 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
481 // Tell MMI that we have debug info.
482 MMI->setDebugInfoAvailability(true);
484 // Prime section data.
485 SectionMap[Asm->getObjFileLowering().getTextSection()];
488 void DwarfDebug::finishVariableDefinitions() {
489 for (const auto &Var : ConcreteVariables) {
490 DIE *VariableDie = Var->getDIE();
492 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
493 // in the ConcreteVariables list, rather than looking it up again here.
494 // DIE::getUnit isn't simple - it walks parent pointers, etc.
495 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
497 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
498 if (AbsVar && AbsVar->getDIE()) {
499 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
502 Unit->applyVariableAttributes(*Var, *VariableDie);
506 void DwarfDebug::finishSubprogramDefinitions() {
507 for (const auto &P : SPMap)
508 P.second->finishSubprogramDefinition(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 DICompileUnit TheCU(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 DIArray Subprograms = TheCU.getSubprograms();
524 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
525 DISubprogram SP(Subprograms.getElement(i));
526 if (ProcessedSPNodes.count(SP) != 0)
528 SPCU->collectDeadVariables(SP);
534 void DwarfDebug::finalizeModuleInfo() {
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 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
566 DwarfAddrSectionSym, DwarfAddrSectionSym);
567 if (!TheCU.getRangeLists().empty())
568 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
569 DwarfDebugRangeSectionSym,
570 DwarfDebugRangeSectionSym);
573 // If we have code split among multiple sections or non-contiguous
574 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
575 // remain in the .o file, otherwise add a DW_AT_low_pc.
576 // FIXME: We should use ranges allow reordering of code ala
577 // .subsections_via_symbols in mach-o. This would mean turning on
578 // ranges for all subprogram DIEs for mach-o.
579 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
580 unsigned NumRanges = TheCU.getRanges().size();
583 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
584 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
585 DwarfDebugRangeSectionSym);
587 // A DW_AT_low_pc attribute may also be specified in combination with
588 // DW_AT_ranges to specify the default base address for use in
589 // location lists (see Section 2.6.2) and range lists (see Section
591 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
593 RangeSpan &Range = TheCU.getRanges().back();
594 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
599 // Compute DIE offsets and sizes.
600 InfoHolder.computeSizeAndOffsets();
602 SkeletonHolder.computeSizeAndOffsets();
605 void DwarfDebug::endSections() {
606 // Filter labels by section.
607 for (const SymbolCU &SCU : ArangeLabels) {
608 if (SCU.Sym->isInSection()) {
609 // Make a note of this symbol and it's section.
610 const MCSection *Section = &SCU.Sym->getSection();
611 if (!Section->getKind().isMetadata())
612 SectionMap[Section].push_back(SCU);
614 // Some symbols (e.g. common/bss on mach-o) can have no section but still
615 // appear in the output. This sucks as we rely on sections to build
616 // arange spans. We can do it without, but it's icky.
617 SectionMap[nullptr].push_back(SCU);
621 // Build a list of sections used.
622 std::vector<const MCSection *> Sections;
623 for (const auto &it : SectionMap) {
624 const MCSection *Section = it.first;
625 Sections.push_back(Section);
628 // Sort the sections into order.
629 // This is only done to ensure consistent output order across different runs.
630 std::sort(Sections.begin(), Sections.end(), SectionSort);
632 // Add terminating symbols for each section.
633 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
634 const MCSection *Section = Sections[ID];
635 MCSymbol *Sym = nullptr;
638 // We can't call MCSection::getLabelEndName, as it's only safe to do so
639 // if we know the section name up-front. For user-created sections, the
640 // resulting label may not be valid to use as a label. (section names can
641 // use a greater set of characters on some systems)
642 Sym = Asm->GetTempSymbol("debug_end", ID);
643 Asm->OutStreamer.SwitchSection(Section);
644 Asm->OutStreamer.EmitLabel(Sym);
647 // Insert a final terminator.
648 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
652 // Emit all Dwarf sections that should come after the content.
653 void DwarfDebug::endModule() {
654 assert(CurFn == nullptr);
655 assert(CurMI == nullptr);
657 // If we aren't actually generating debug info (check beginModule -
658 // conditionalized on !DisableDebugInfoPrinting and the presence of the
659 // llvm.dbg.cu metadata node)
660 if (!DwarfInfoSectionSym)
663 // End any existing sections.
664 // TODO: Does this need to happen?
667 // Finalize the debug info for the module.
668 finalizeModuleInfo();
672 // Emit all the DIEs into a debug info section.
675 // Corresponding abbreviations into a abbrev section.
678 // Emit info into a debug aranges section.
679 if (GenerateARangeSection)
682 // Emit info into a debug ranges section.
685 if (useSplitDwarf()) {
688 emitDebugAbbrevDWO();
691 // Emit DWO addresses.
692 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
694 // Emit info into a debug loc section.
697 // Emit info into the dwarf accelerator table sections.
698 if (useDwarfAccelTables()) {
701 emitAccelNamespaces();
705 // Emit the pubnames and pubtypes sections if requested.
706 if (HasDwarfPubSections) {
707 emitDebugPubNames(GenerateGnuPubSections);
708 emitDebugPubTypes(GenerateGnuPubSections);
713 AbstractVariables.clear();
716 // Find abstract variable, if any, associated with Var.
717 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
718 DIVariable &Cleansed) {
719 LLVMContext &Ctx = DV->getContext();
720 // More then one inlined variable corresponds to one abstract variable.
721 // FIXME: This duplication of variables when inlining should probably be
722 // removed. It's done to allow each DIVariable to describe its location
723 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
724 // make it accurate then remove this duplication/cleansing stuff.
725 Cleansed = cleanseInlinedVariable(DV, Ctx);
726 auto I = AbstractVariables.find(Cleansed);
727 if (I != AbstractVariables.end())
728 return I->second.get();
732 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
734 return getExistingAbstractVariable(DV, Cleansed);
737 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
738 LexicalScope *Scope) {
739 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
740 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
741 AbstractVariables[Var] = std::move(AbsDbgVariable);
744 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
745 const MDNode *ScopeNode) {
746 DIVariable Cleansed = DV;
747 if (getExistingAbstractVariable(DV, Cleansed))
750 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
754 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
755 const MDNode *ScopeNode) {
756 DIVariable Cleansed = DV;
757 if (getExistingAbstractVariable(DV, Cleansed))
760 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
761 createAbstractVariable(Cleansed, Scope);
764 // Collect variable information from side table maintained by MMI.
765 void DwarfDebug::collectVariableInfoFromMMITable(
766 SmallPtrSetImpl<const MDNode *> &Processed) {
767 for (const auto &VI : MMI->getVariableDbgInfo()) {
770 Processed.insert(VI.Var);
771 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
773 // If variable scope is not found then skip this variable.
777 DIVariable DV(VI.Var);
778 DIExpression Expr(VI.Expr);
779 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
780 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
781 DbgVariable *RegVar = ConcreteVariables.back().get();
782 RegVar->setFrameIndex(VI.Slot);
783 InfoHolder.addScopeVariable(Scope, RegVar);
787 // Get .debug_loc entry for the instruction range starting at MI.
788 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
789 const MDNode *Expr = MI->getDebugExpression();
790 const MDNode *Var = MI->getDebugVariable();
792 assert(MI->getNumOperands() == 4);
793 if (MI->getOperand(0).isReg()) {
794 MachineLocation MLoc;
795 // If the second operand is an immediate, this is a
796 // register-indirect address.
797 if (!MI->getOperand(1).isImm())
798 MLoc.set(MI->getOperand(0).getReg());
800 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
801 return DebugLocEntry::Value(Var, Expr, MLoc);
803 if (MI->getOperand(0).isImm())
804 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
805 if (MI->getOperand(0).isFPImm())
806 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
807 if (MI->getOperand(0).isCImm())
808 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
810 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
813 /// Determine whether two variable pieces overlap.
814 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
815 if (!P1.isVariablePiece() || !P2.isVariablePiece())
817 unsigned l1 = P1.getPieceOffset();
818 unsigned l2 = P2.getPieceOffset();
819 unsigned r1 = l1 + P1.getPieceSize();
820 unsigned r2 = l2 + P2.getPieceSize();
821 // True where [l1,r1[ and [r1,r2[ overlap.
822 return (l1 < r2) && (l2 < r1);
825 /// Build the location list for all DBG_VALUEs in the function that
826 /// describe the same variable. If the ranges of several independent
827 /// pieces of the same variable overlap partially, split them up and
828 /// combine the ranges. The resulting DebugLocEntries are will have
829 /// strict monotonically increasing begin addresses and will never
834 // Ranges History [var, loc, piece ofs size]
835 // 0 | [x, (reg0, piece 0, 32)]
836 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
838 // 3 | [clobber reg0]
839 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
843 // [0-1] [x, (reg0, piece 0, 32)]
844 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
845 // [3-4] [x, (reg1, piece 32, 32)]
846 // [4- ] [x, (mem, piece 0, 64)]
848 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
849 const DbgValueHistoryMap::InstrRanges &Ranges) {
850 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
852 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
853 const MachineInstr *Begin = I->first;
854 const MachineInstr *End = I->second;
855 assert(Begin->isDebugValue() && "Invalid History entry");
857 // Check if a variable is inaccessible in this range.
858 if (Begin->getNumOperands() > 1 &&
859 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
864 // If this piece overlaps with any open ranges, truncate them.
865 DIExpression DIExpr = Begin->getDebugExpression();
866 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
867 [&](DebugLocEntry::Value R) {
868 return piecesOverlap(DIExpr, R.getExpression());
870 OpenRanges.erase(Last, OpenRanges.end());
872 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
873 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
875 const MCSymbol *EndLabel;
877 EndLabel = getLabelAfterInsn(End);
878 else if (std::next(I) == Ranges.end())
879 EndLabel = FunctionEndSym;
881 EndLabel = getLabelBeforeInsn(std::next(I)->first);
882 assert(EndLabel && "Forgot label after instruction ending a range!");
884 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
886 auto Value = getDebugLocValue(Begin);
887 DebugLocEntry Loc(StartLabel, EndLabel, Value);
888 bool couldMerge = false;
890 // If this is a piece, it may belong to the current DebugLocEntry.
891 if (DIExpr.isVariablePiece()) {
892 // Add this value to the list of open ranges.
893 OpenRanges.push_back(Value);
895 // Attempt to add the piece to the last entry.
896 if (!DebugLoc.empty())
897 if (DebugLoc.back().MergeValues(Loc))
902 // Need to add a new DebugLocEntry. Add all values from still
903 // valid non-overlapping pieces.
904 if (OpenRanges.size())
905 Loc.addValues(OpenRanges);
907 DebugLoc.push_back(std::move(Loc));
910 // Attempt to coalesce the ranges of two otherwise identical
912 auto CurEntry = DebugLoc.rbegin();
913 auto PrevEntry = std::next(CurEntry);
914 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
918 dbgs() << CurEntry->getValues().size() << " Values:\n";
919 for (auto Value : CurEntry->getValues()) {
920 Value.getVariable()->dump();
921 Value.getExpression()->dump();
929 // Find variables for each lexical scope.
931 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
932 SmallPtrSetImpl<const MDNode *> &Processed) {
933 // Grab the variable info that was squirreled away in the MMI side-table.
934 collectVariableInfoFromMMITable(Processed);
936 for (const auto &I : DbgValues) {
937 DIVariable DV(I.first);
938 if (Processed.count(DV))
941 // Instruction ranges, specifying where DV is accessible.
942 const auto &Ranges = I.second;
946 LexicalScope *Scope = nullptr;
947 if (MDNode *IA = DV.getInlinedAt()) {
948 DebugLoc DL = DebugLoc::getFromDILocation(IA);
949 Scope = LScopes.findInlinedScope(DebugLoc::get(
950 DL.getLine(), DL.getCol(), DV.getContext(), IA));
952 Scope = LScopes.findLexicalScope(DV.getContext());
953 // If variable scope is not found then skip this variable.
957 Processed.insert(DV);
958 const MachineInstr *MInsn = Ranges.front().first;
959 assert(MInsn->isDebugValue() && "History must begin with debug value");
960 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
961 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
962 DbgVariable *RegVar = ConcreteVariables.back().get();
963 InfoHolder.addScopeVariable(Scope, RegVar);
965 // Check if the first DBG_VALUE is valid for the rest of the function.
966 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
969 // Handle multiple DBG_VALUE instructions describing one variable.
970 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
972 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
973 DebugLocList &LocList = DotDebugLocEntries.back();
976 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
978 // Build the location list for this variable.
979 buildLocationList(LocList.List, Ranges);
982 // Collect info for variables that were optimized out.
983 DIArray Variables = SP.getVariables();
984 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
985 DIVariable DV(Variables.getElement(i));
986 assert(DV.isVariable());
987 if (!Processed.insert(DV))
989 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
990 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
992 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
993 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
998 // Return Label preceding the instruction.
999 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1000 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1001 assert(Label && "Didn't insert label before instruction");
1005 // Return Label immediately following the instruction.
1006 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1007 return LabelsAfterInsn.lookup(MI);
1010 // Process beginning of an instruction.
1011 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1012 assert(CurMI == nullptr);
1014 // Check if source location changes, but ignore DBG_VALUE locations.
1015 if (!MI->isDebugValue()) {
1016 DebugLoc DL = MI->getDebugLoc();
1017 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1020 if (DL == PrologEndLoc) {
1021 Flags |= DWARF2_FLAG_PROLOGUE_END;
1022 PrologEndLoc = DebugLoc();
1024 if (PrologEndLoc.isUnknown())
1025 Flags |= DWARF2_FLAG_IS_STMT;
1027 if (!DL.isUnknown()) {
1028 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1029 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1031 recordSourceLine(0, 0, nullptr, 0);
1035 // Insert labels where requested.
1036 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1037 LabelsBeforeInsn.find(MI);
1040 if (I == LabelsBeforeInsn.end())
1043 // Label already assigned.
1048 PrevLabel = MMI->getContext().CreateTempSymbol();
1049 Asm->OutStreamer.EmitLabel(PrevLabel);
1051 I->second = PrevLabel;
1054 // Process end of an instruction.
1055 void DwarfDebug::endInstruction() {
1056 assert(CurMI != nullptr);
1057 // Don't create a new label after DBG_VALUE instructions.
1058 // They don't generate code.
1059 if (!CurMI->isDebugValue())
1060 PrevLabel = nullptr;
1062 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1063 LabelsAfterInsn.find(CurMI);
1067 if (I == LabelsAfterInsn.end())
1070 // Label already assigned.
1074 // We need a label after this instruction.
1076 PrevLabel = MMI->getContext().CreateTempSymbol();
1077 Asm->OutStreamer.EmitLabel(PrevLabel);
1079 I->second = PrevLabel;
1082 // Each LexicalScope has first instruction and last instruction to mark
1083 // beginning and end of a scope respectively. Create an inverse map that list
1084 // scopes starts (and ends) with an instruction. One instruction may start (or
1085 // end) multiple scopes. Ignore scopes that are not reachable.
1086 void DwarfDebug::identifyScopeMarkers() {
1087 SmallVector<LexicalScope *, 4> WorkList;
1088 WorkList.push_back(LScopes.getCurrentFunctionScope());
1089 while (!WorkList.empty()) {
1090 LexicalScope *S = WorkList.pop_back_val();
1092 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1093 if (!Children.empty())
1094 WorkList.append(Children.begin(), Children.end());
1096 if (S->isAbstractScope())
1099 for (const InsnRange &R : S->getRanges()) {
1100 assert(R.first && "InsnRange does not have first instruction!");
1101 assert(R.second && "InsnRange does not have second instruction!");
1102 requestLabelBeforeInsn(R.first);
1103 requestLabelAfterInsn(R.second);
1108 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1109 // First known non-DBG_VALUE and non-frame setup location marks
1110 // the beginning of the function body.
1111 for (const auto &MBB : *MF)
1112 for (const auto &MI : MBB)
1113 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1114 !MI.getDebugLoc().isUnknown())
1115 return MI.getDebugLoc();
1119 // Gather pre-function debug information. Assumes being called immediately
1120 // after the function entry point has been emitted.
1121 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1124 // If there's no debug info for the function we're not going to do anything.
1125 if (!MMI->hasDebugInfo())
1128 auto DI = FunctionDIs.find(MF->getFunction());
1129 if (DI == FunctionDIs.end())
1132 // Grab the lexical scopes for the function, if we don't have any of those
1133 // then we're not going to be able to do anything.
1134 LScopes.initialize(*MF);
1135 if (LScopes.empty())
1138 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1140 // Make sure that each lexical scope will have a begin/end label.
1141 identifyScopeMarkers();
1143 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1144 // belongs to so that we add to the correct per-cu line table in the
1146 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1147 // FnScope->getScopeNode() and DI->second should represent the same function,
1148 // though they may not be the same MDNode due to inline functions merged in
1149 // LTO where the debug info metadata still differs (either due to distinct
1150 // written differences - two versions of a linkonce_odr function
1151 // written/copied into two separate files, or some sub-optimal metadata that
1152 // isn't structurally identical (see: file path/name info from clang, which
1153 // includes the directory of the cpp file being built, even when the file name
1154 // is absolute (such as an <> lookup header)))
1155 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1156 assert(TheCU && "Unable to find compile unit!");
1157 if (Asm->OutStreamer.hasRawTextSupport())
1158 // Use a single line table if we are generating assembly.
1159 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1161 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1163 // Emit a label for the function so that we have a beginning address.
1164 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1165 // Assumes in correct section after the entry point.
1166 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1168 // Calculate history for local variables.
1169 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1172 // Request labels for the full history.
1173 for (const auto &I : DbgValues) {
1174 const auto &Ranges = I.second;
1178 // The first mention of a function argument gets the FunctionBeginSym
1179 // label, so arguments are visible when breaking at function entry.
1180 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1181 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1182 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1183 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1184 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1185 // Mark all non-overlapping initial pieces.
1186 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1187 DIExpression Piece = I->first->getDebugExpression();
1188 if (std::all_of(Ranges.begin(), I,
1189 [&](DbgValueHistoryMap::InstrRange Pred) {
1190 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1192 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1199 for (const auto &Range : Ranges) {
1200 requestLabelBeforeInsn(Range.first);
1202 requestLabelAfterInsn(Range.second);
1206 PrevInstLoc = DebugLoc();
1207 PrevLabel = FunctionBeginSym;
1209 // Record beginning of function.
1210 PrologEndLoc = findPrologueEndLoc(MF);
1211 if (!PrologEndLoc.isUnknown()) {
1212 DebugLoc FnStartDL =
1213 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1215 FnStartDL.getLine(), FnStartDL.getCol(),
1216 FnStartDL.getScope(MF->getFunction()->getContext()),
1217 // We'd like to list the prologue as "not statements" but GDB behaves
1218 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1219 DWARF2_FLAG_IS_STMT);
1223 // Gather and emit post-function debug information.
1224 void DwarfDebug::endFunction(const MachineFunction *MF) {
1225 assert(CurFn == MF &&
1226 "endFunction should be called with the same function as beginFunction");
1228 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1229 !FunctionDIs.count(MF->getFunction())) {
1230 // If we don't have a lexical scope for this function then there will
1231 // be a hole in the range information. Keep note of this by setting the
1232 // previously used section to nullptr.
1238 // Define end label for subprogram.
1239 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1240 // Assumes in correct section after the entry point.
1241 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1243 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1244 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1246 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1247 DISubprogram SP(FnScope->getScopeNode());
1248 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1250 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1251 collectVariableInfo(TheCU, SP, ProcessedVars);
1253 // Add the range of this function to the list of ranges for the CU.
1254 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1256 // Under -gmlt, skip building the subprogram if there are no inlined
1257 // subroutines inside it.
1258 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1259 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1260 assert(InfoHolder.getScopeVariables().empty());
1261 assert(DbgValues.empty());
1262 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1263 // by a -gmlt CU. Add a test and remove this assertion.
1264 assert(AbstractVariables.empty());
1265 LabelsBeforeInsn.clear();
1266 LabelsAfterInsn.clear();
1267 PrevLabel = nullptr;
1273 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1275 // Construct abstract scopes.
1276 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1277 DISubprogram SP(AScope->getScopeNode());
1278 assert(SP.isSubprogram());
1279 // Collect info for variables that were optimized out.
1280 DIArray Variables = SP.getVariables();
1281 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1282 DIVariable DV(Variables.getElement(i));
1283 assert(DV && DV.isVariable());
1284 if (!ProcessedVars.insert(DV))
1286 ensureAbstractVariableIsCreated(DV, DV.getContext());
1287 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1288 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1290 constructAbstractSubprogramScopeDIE(AScope);
1293 TheCU.constructSubprogramScopeDIE(FnScope);
1296 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1297 // DbgVariables except those that are also in AbstractVariables (since they
1298 // can be used cross-function)
1299 InfoHolder.getScopeVariables().clear();
1301 LabelsBeforeInsn.clear();
1302 LabelsAfterInsn.clear();
1303 PrevLabel = nullptr;
1307 // Register a source line with debug info. Returns the unique label that was
1308 // emitted and which provides correspondence to the source line list.
1309 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1314 unsigned Discriminator = 0;
1315 if (DIScope Scope = DIScope(S)) {
1316 assert(Scope.isScope());
1317 Fn = Scope.getFilename();
1318 Dir = Scope.getDirectory();
1319 if (Scope.isLexicalBlockFile())
1320 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1322 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1323 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1324 .getOrCreateSourceID(Fn, Dir);
1326 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1330 //===----------------------------------------------------------------------===//
1332 //===----------------------------------------------------------------------===//
1334 // Emit initial Dwarf sections with a label at the start of each one.
1335 void DwarfDebug::emitSectionLabels() {
1336 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1338 // Dwarf sections base addresses.
1339 DwarfInfoSectionSym =
1340 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1341 if (useSplitDwarf()) {
1342 DwarfInfoDWOSectionSym =
1343 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1344 DwarfTypesDWOSectionSym =
1345 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1347 DwarfAbbrevSectionSym =
1348 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1349 if (useSplitDwarf())
1350 DwarfAbbrevDWOSectionSym = emitSectionSym(
1351 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1352 if (GenerateARangeSection)
1353 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1355 DwarfLineSectionSym =
1356 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1357 if (GenerateGnuPubSections) {
1358 DwarfGnuPubNamesSectionSym =
1359 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1360 DwarfGnuPubTypesSectionSym =
1361 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1362 } else if (HasDwarfPubSections) {
1363 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1364 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1367 DwarfStrSectionSym =
1368 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1369 if (useSplitDwarf()) {
1370 DwarfStrDWOSectionSym =
1371 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1372 DwarfAddrSectionSym =
1373 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1374 DwarfDebugLocSectionSym =
1375 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1377 DwarfDebugLocSectionSym =
1378 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1379 DwarfDebugRangeSectionSym =
1380 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1383 // Recursively emits a debug information entry.
1384 void DwarfDebug::emitDIE(DIE &Die) {
1385 // Get the abbreviation for this DIE.
1386 const DIEAbbrev &Abbrev = Die.getAbbrev();
1388 // Emit the code (index) for the abbreviation.
1389 if (Asm->isVerbose())
1390 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1391 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1392 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1393 dwarf::TagString(Abbrev.getTag()));
1394 Asm->EmitULEB128(Abbrev.getNumber());
1396 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1397 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1399 // Emit the DIE attribute values.
1400 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1401 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1402 dwarf::Form Form = AbbrevData[i].getForm();
1403 assert(Form && "Too many attributes for DIE (check abbreviation)");
1405 if (Asm->isVerbose()) {
1406 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1407 if (Attr == dwarf::DW_AT_accessibility)
1408 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1409 cast<DIEInteger>(Values[i])->getValue()));
1412 // Emit an attribute using the defined form.
1413 Values[i]->EmitValue(Asm, Form);
1416 // Emit the DIE children if any.
1417 if (Abbrev.hasChildren()) {
1418 for (auto &Child : Die.getChildren())
1421 Asm->OutStreamer.AddComment("End Of Children Mark");
1426 // Emit the debug info section.
1427 void DwarfDebug::emitDebugInfo() {
1428 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1430 Holder.emitUnits(DwarfAbbrevSectionSym);
1433 // Emit the abbreviation section.
1434 void DwarfDebug::emitAbbreviations() {
1435 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1437 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1440 // Emit the last address of the section and the end of the line matrix.
1441 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1442 // Define last address of section.
1443 Asm->OutStreamer.AddComment("Extended Op");
1446 Asm->OutStreamer.AddComment("Op size");
1447 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1448 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1449 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1451 Asm->OutStreamer.AddComment("Section end label");
1453 Asm->OutStreamer.EmitSymbolValue(
1454 Asm->GetTempSymbol("section_end", SectionEnd),
1455 Asm->getDataLayout().getPointerSize());
1457 // Mark end of matrix.
1458 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1464 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1465 StringRef TableName, StringRef SymName) {
1466 Accel.FinalizeTable(Asm, TableName);
1467 Asm->OutStreamer.SwitchSection(Section);
1468 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1469 Asm->OutStreamer.EmitLabel(SectionBegin);
1471 // Emit the full data.
1472 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1475 // Emit visible names into a hashed accelerator table section.
1476 void DwarfDebug::emitAccelNames() {
1477 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1478 "Names", "names_begin");
1481 // Emit objective C classes and categories into a hashed accelerator table
1483 void DwarfDebug::emitAccelObjC() {
1484 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1485 "ObjC", "objc_begin");
1488 // Emit namespace dies into a hashed accelerator table.
1489 void DwarfDebug::emitAccelNamespaces() {
1490 emitAccel(AccelNamespace,
1491 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1492 "namespac", "namespac_begin");
1495 // Emit type dies into a hashed accelerator table.
1496 void DwarfDebug::emitAccelTypes() {
1497 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1498 "types", "types_begin");
1501 // Public name handling.
1502 // The format for the various pubnames:
1504 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1505 // for the DIE that is named.
1507 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1508 // into the CU and the index value is computed according to the type of value
1509 // for the DIE that is named.
1511 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1512 // it's the offset within the debug_info/debug_types dwo section, however, the
1513 // reference in the pubname header doesn't change.
1515 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1516 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1518 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1520 // We could have a specification DIE that has our most of our knowledge,
1521 // look for that now.
1522 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1524 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1525 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1526 Linkage = dwarf::GIEL_EXTERNAL;
1527 } else if (Die->findAttribute(dwarf::DW_AT_external))
1528 Linkage = dwarf::GIEL_EXTERNAL;
1530 switch (Die->getTag()) {
1531 case dwarf::DW_TAG_class_type:
1532 case dwarf::DW_TAG_structure_type:
1533 case dwarf::DW_TAG_union_type:
1534 case dwarf::DW_TAG_enumeration_type:
1535 return dwarf::PubIndexEntryDescriptor(
1536 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1537 ? dwarf::GIEL_STATIC
1538 : dwarf::GIEL_EXTERNAL);
1539 case dwarf::DW_TAG_typedef:
1540 case dwarf::DW_TAG_base_type:
1541 case dwarf::DW_TAG_subrange_type:
1542 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1543 case dwarf::DW_TAG_namespace:
1544 return dwarf::GIEK_TYPE;
1545 case dwarf::DW_TAG_subprogram:
1546 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1547 case dwarf::DW_TAG_constant:
1548 case dwarf::DW_TAG_variable:
1549 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1550 case dwarf::DW_TAG_enumerator:
1551 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1552 dwarf::GIEL_STATIC);
1554 return dwarf::GIEK_NONE;
1558 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1560 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1561 const MCSection *PSec =
1562 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1563 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1565 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1568 void DwarfDebug::emitDebugPubSection(
1569 bool GnuStyle, const MCSection *PSec, StringRef Name,
1570 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1571 for (const auto &NU : CUMap) {
1572 DwarfCompileUnit *TheU = NU.second;
1574 const auto &Globals = (TheU->*Accessor)();
1576 if (Globals.empty())
1579 if (auto *Skeleton = TheU->getSkeleton())
1581 unsigned ID = TheU->getUniqueID();
1583 // Start the dwarf pubnames section.
1584 Asm->OutStreamer.SwitchSection(PSec);
1587 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1588 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1589 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1590 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1592 Asm->OutStreamer.EmitLabel(BeginLabel);
1594 Asm->OutStreamer.AddComment("DWARF Version");
1595 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1597 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1598 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1600 Asm->OutStreamer.AddComment("Compilation Unit Length");
1601 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1603 // Emit the pubnames for this compilation unit.
1604 for (const auto &GI : Globals) {
1605 const char *Name = GI.getKeyData();
1606 const DIE *Entity = GI.second;
1608 Asm->OutStreamer.AddComment("DIE offset");
1609 Asm->EmitInt32(Entity->getOffset());
1612 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1613 Asm->OutStreamer.AddComment(
1614 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1615 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1616 Asm->EmitInt8(Desc.toBits());
1619 Asm->OutStreamer.AddComment("External Name");
1620 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1623 Asm->OutStreamer.AddComment("End Mark");
1625 Asm->OutStreamer.EmitLabel(EndLabel);
1629 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1630 const MCSection *PSec =
1631 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1632 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1634 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1637 // Emit visible names into a debug str section.
1638 void DwarfDebug::emitDebugStr() {
1639 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1640 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1643 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1644 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1645 const DITypeIdentifierMap &Map,
1646 ArrayRef<DebugLocEntry::Value> Values) {
1647 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1648 return P.isVariablePiece();
1649 }) && "all values are expected to be pieces");
1650 assert(std::is_sorted(Values.begin(), Values.end()) &&
1651 "pieces are expected to be sorted");
1653 unsigned Offset = 0;
1654 for (auto Piece : Values) {
1655 DIExpression Expr = Piece.getExpression();
1656 unsigned PieceOffset = Expr.getPieceOffset();
1657 unsigned PieceSize = Expr.getPieceSize();
1658 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1659 if (Offset < PieceOffset) {
1660 // The DWARF spec seriously mandates pieces with no locations for gaps.
1661 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1662 Offset += PieceOffset-Offset;
1665 Offset += PieceSize;
1667 const unsigned SizeOfByte = 8;
1669 DIVariable Var = Piece.getVariable();
1670 assert(!Var.isIndirect() && "indirect address for piece");
1671 unsigned VarSize = Var.getSizeInBits(Map);
1672 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1673 && "piece is larger than or outside of variable");
1674 assert(PieceSize*SizeOfByte != VarSize
1675 && "piece covers entire variable");
1677 if (Piece.isLocation() && Piece.getLoc().isReg())
1678 Asm->EmitDwarfRegOpPiece(Streamer,
1680 PieceSize*SizeOfByte);
1682 emitDebugLocValue(Streamer, Piece);
1683 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1689 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1690 const DebugLocEntry &Entry) {
1691 const DebugLocEntry::Value Value = Entry.getValues()[0];
1692 if (Value.isVariablePiece())
1693 // Emit all pieces that belong to the same variable and range.
1694 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1696 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1697 emitDebugLocValue(Streamer, Value);
1700 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1701 const DebugLocEntry::Value &Value) {
1702 DIVariable DV = Value.getVariable();
1704 if (Value.isInt()) {
1705 DIBasicType BTy(resolve(DV.getType()));
1706 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1707 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1708 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1709 Streamer.EmitSLEB128(Value.getInt());
1711 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1712 Streamer.EmitULEB128(Value.getInt());
1714 } else if (Value.isLocation()) {
1715 MachineLocation Loc = Value.getLoc();
1716 DIExpression Expr = Value.getExpression();
1719 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1721 // Complex address entry.
1722 unsigned N = Expr.getNumElements();
1724 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1725 if (Loc.getOffset()) {
1727 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1728 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1729 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1730 Streamer.EmitSLEB128(Expr.getElement(1));
1732 // If first address element is OpPlus then emit
1733 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1734 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1735 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1739 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1742 // Emit remaining complex address elements.
1743 for (; i < N; ++i) {
1744 uint64_t Element = Expr.getElement(i);
1745 if (Element == dwarf::DW_OP_plus) {
1746 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1747 Streamer.EmitULEB128(Expr.getElement(++i));
1748 } else if (Element == dwarf::DW_OP_deref) {
1750 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1751 } else if (Element == dwarf::DW_OP_piece) {
1753 // handled in emitDebugLocEntry.
1755 llvm_unreachable("unknown Opcode found in complex address");
1759 // else ... ignore constant fp. There is not any good way to
1760 // to represent them here in dwarf.
1764 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1765 Asm->OutStreamer.AddComment("Loc expr size");
1766 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1767 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1768 Asm->EmitLabelDifference(end, begin, 2);
1769 Asm->OutStreamer.EmitLabel(begin);
1771 APByteStreamer Streamer(*Asm);
1772 emitDebugLocEntry(Streamer, Entry);
1774 Asm->OutStreamer.EmitLabel(end);
1777 // Emit locations into the debug loc section.
1778 void DwarfDebug::emitDebugLoc() {
1779 // Start the dwarf loc section.
1780 Asm->OutStreamer.SwitchSection(
1781 Asm->getObjFileLowering().getDwarfLocSection());
1782 unsigned char Size = Asm->getDataLayout().getPointerSize();
1783 for (const auto &DebugLoc : DotDebugLocEntries) {
1784 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1785 const DwarfCompileUnit *CU = DebugLoc.CU;
1786 assert(!CU->getRanges().empty());
1787 for (const auto &Entry : DebugLoc.List) {
1788 // Set up the range. This range is relative to the entry point of the
1789 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1790 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1791 if (CU->getRanges().size() == 1) {
1792 // Grab the begin symbol from the first range as our base.
1793 const MCSymbol *Base = CU->getRanges()[0].getStart();
1794 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1795 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1797 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1798 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1801 emitDebugLocEntryLocation(Entry);
1803 Asm->OutStreamer.EmitIntValue(0, Size);
1804 Asm->OutStreamer.EmitIntValue(0, Size);
1808 void DwarfDebug::emitDebugLocDWO() {
1809 Asm->OutStreamer.SwitchSection(
1810 Asm->getObjFileLowering().getDwarfLocDWOSection());
1811 for (const auto &DebugLoc : DotDebugLocEntries) {
1812 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1813 for (const auto &Entry : DebugLoc.List) {
1814 // Just always use start_length for now - at least that's one address
1815 // rather than two. We could get fancier and try to, say, reuse an
1816 // address we know we've emitted elsewhere (the start of the function?
1817 // The start of the CU or CU subrange that encloses this range?)
1818 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1819 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1820 Asm->EmitULEB128(idx);
1821 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1823 emitDebugLocEntryLocation(Entry);
1825 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1830 const MCSymbol *Start, *End;
1833 // Emit a debug aranges section, containing a CU lookup for any
1834 // address we can tie back to a CU.
1835 void DwarfDebug::emitDebugARanges() {
1836 // Start the dwarf aranges section.
1837 Asm->OutStreamer.SwitchSection(
1838 Asm->getObjFileLowering().getDwarfARangesSection());
1840 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1844 // Build a list of sections used.
1845 std::vector<const MCSection *> Sections;
1846 for (const auto &it : SectionMap) {
1847 const MCSection *Section = it.first;
1848 Sections.push_back(Section);
1851 // Sort the sections into order.
1852 // This is only done to ensure consistent output order across different runs.
1853 std::sort(Sections.begin(), Sections.end(), SectionSort);
1855 // Build a set of address spans, sorted by CU.
1856 for (const MCSection *Section : Sections) {
1857 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1858 if (List.size() < 2)
1861 // Sort the symbols by offset within the section.
1862 std::sort(List.begin(), List.end(),
1863 [&](const SymbolCU &A, const SymbolCU &B) {
1864 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1865 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1867 // Symbols with no order assigned should be placed at the end.
1868 // (e.g. section end labels)
1876 // If we have no section (e.g. common), just write out
1877 // individual spans for each symbol.
1879 for (const SymbolCU &Cur : List) {
1881 Span.Start = Cur.Sym;
1884 Spans[Cur.CU].push_back(Span);
1887 // Build spans between each label.
1888 const MCSymbol *StartSym = List[0].Sym;
1889 for (size_t n = 1, e = List.size(); n < e; n++) {
1890 const SymbolCU &Prev = List[n - 1];
1891 const SymbolCU &Cur = List[n];
1893 // Try and build the longest span we can within the same CU.
1894 if (Cur.CU != Prev.CU) {
1896 Span.Start = StartSym;
1898 Spans[Prev.CU].push_back(Span);
1905 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1907 // Build a list of CUs used.
1908 std::vector<DwarfCompileUnit *> CUs;
1909 for (const auto &it : Spans) {
1910 DwarfCompileUnit *CU = it.first;
1914 // Sort the CU list (again, to ensure consistent output order).
1915 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1916 return A->getUniqueID() < B->getUniqueID();
1919 // Emit an arange table for each CU we used.
1920 for (DwarfCompileUnit *CU : CUs) {
1921 std::vector<ArangeSpan> &List = Spans[CU];
1923 // Emit size of content not including length itself.
1924 unsigned ContentSize =
1925 sizeof(int16_t) + // DWARF ARange version number
1926 sizeof(int32_t) + // Offset of CU in the .debug_info section
1927 sizeof(int8_t) + // Pointer Size (in bytes)
1928 sizeof(int8_t); // Segment Size (in bytes)
1930 unsigned TupleSize = PtrSize * 2;
1932 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1934 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1936 ContentSize += Padding;
1937 ContentSize += (List.size() + 1) * TupleSize;
1939 // For each compile unit, write the list of spans it covers.
1940 Asm->OutStreamer.AddComment("Length of ARange Set");
1941 Asm->EmitInt32(ContentSize);
1942 Asm->OutStreamer.AddComment("DWARF Arange version number");
1943 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1944 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1945 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1946 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1947 Asm->EmitInt8(PtrSize);
1948 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1951 Asm->OutStreamer.EmitFill(Padding, 0xff);
1953 for (const ArangeSpan &Span : List) {
1954 Asm->EmitLabelReference(Span.Start, PtrSize);
1956 // Calculate the size as being from the span start to it's end.
1958 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1960 // For symbols without an end marker (e.g. common), we
1961 // write a single arange entry containing just that one symbol.
1962 uint64_t Size = SymSize[Span.Start];
1966 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1970 Asm->OutStreamer.AddComment("ARange terminator");
1971 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1972 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1976 // Emit visible names into a debug ranges section.
1977 void DwarfDebug::emitDebugRanges() {
1978 // Start the dwarf ranges section.
1979 Asm->OutStreamer.SwitchSection(
1980 Asm->getObjFileLowering().getDwarfRangesSection());
1982 // Size for our labels.
1983 unsigned char Size = Asm->getDataLayout().getPointerSize();
1985 // Grab the specific ranges for the compile units in the module.
1986 for (const auto &I : CUMap) {
1987 DwarfCompileUnit *TheCU = I.second;
1989 // Iterate over the misc ranges for the compile units in the module.
1990 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1991 // Emit our symbol so we can find the beginning of the range.
1992 Asm->OutStreamer.EmitLabel(List.getSym());
1994 for (const RangeSpan &Range : List.getRanges()) {
1995 const MCSymbol *Begin = Range.getStart();
1996 const MCSymbol *End = Range.getEnd();
1997 assert(Begin && "Range without a begin symbol?");
1998 assert(End && "Range without an end symbol?");
1999 if (TheCU->getRanges().size() == 1) {
2000 // Grab the begin symbol from the first range as our base.
2001 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2002 Asm->EmitLabelDifference(Begin, Base, Size);
2003 Asm->EmitLabelDifference(End, Base, Size);
2005 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2006 Asm->OutStreamer.EmitSymbolValue(End, Size);
2010 // And terminate the list with two 0 values.
2011 Asm->OutStreamer.EmitIntValue(0, Size);
2012 Asm->OutStreamer.EmitIntValue(0, Size);
2015 // Now emit a range for the CU itself.
2016 if (TheCU->getRanges().size() > 1) {
2017 Asm->OutStreamer.EmitLabel(
2018 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2019 for (const RangeSpan &Range : TheCU->getRanges()) {
2020 const MCSymbol *Begin = Range.getStart();
2021 const MCSymbol *End = Range.getEnd();
2022 assert(Begin && "Range without a begin symbol?");
2023 assert(End && "Range without an end symbol?");
2024 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2025 Asm->OutStreamer.EmitSymbolValue(End, Size);
2027 // And terminate the list with two 0 values.
2028 Asm->OutStreamer.EmitIntValue(0, Size);
2029 Asm->OutStreamer.EmitIntValue(0, Size);
2034 // DWARF5 Experimental Separate Dwarf emitters.
2036 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2037 std::unique_ptr<DwarfUnit> NewU) {
2038 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2039 U.getCUNode().getSplitDebugFilename());
2041 if (!CompilationDir.empty())
2042 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2044 addGnuPubAttributes(*NewU, Die);
2046 SkeletonHolder.addUnit(std::move(NewU));
2049 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2050 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2051 // DW_AT_addr_base, DW_AT_ranges_base.
2052 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2054 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2055 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2056 DwarfCompileUnit &NewCU = *OwnedUnit;
2057 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2058 DwarfInfoSectionSym);
2060 NewCU.initStmtList(DwarfLineSectionSym);
2062 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2067 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2068 // compile units that would normally be in debug_info.
2069 void DwarfDebug::emitDebugInfoDWO() {
2070 assert(useSplitDwarf() && "No split dwarf debug info?");
2071 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2072 // emit relocations into the dwo file.
2073 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2076 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2077 // abbreviations for the .debug_info.dwo section.
2078 void DwarfDebug::emitDebugAbbrevDWO() {
2079 assert(useSplitDwarf() && "No split dwarf?");
2080 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2083 void DwarfDebug::emitDebugLineDWO() {
2084 assert(useSplitDwarf() && "No split dwarf?");
2085 Asm->OutStreamer.SwitchSection(
2086 Asm->getObjFileLowering().getDwarfLineDWOSection());
2087 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2090 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2091 // string section and is identical in format to traditional .debug_str
2093 void DwarfDebug::emitDebugStrDWO() {
2094 assert(useSplitDwarf() && "No split dwarf?");
2095 const MCSection *OffSec =
2096 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2097 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2101 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2102 if (!useSplitDwarf())
2105 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2106 return &SplitTypeUnitFileTable;
2109 static uint64_t makeTypeSignature(StringRef Identifier) {
2111 Hash.update(Identifier);
2112 // ... take the least significant 8 bytes and return those. Our MD5
2113 // implementation always returns its results in little endian, swap bytes
2115 MD5::MD5Result Result;
2117 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2120 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2121 StringRef Identifier, DIE &RefDie,
2122 DICompositeType CTy) {
2123 // Fast path if we're building some type units and one has already used the
2124 // address pool we know we're going to throw away all this work anyway, so
2125 // don't bother building dependent types.
2126 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2129 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2131 CU.addDIETypeSignature(RefDie, *TU);
2135 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2136 AddrPool.resetUsedFlag();
2138 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2139 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2140 this, &InfoHolder, getDwoLineTable(CU));
2141 DwarfTypeUnit &NewTU = *OwnedUnit;
2142 DIE &UnitDie = NewTU.getUnitDie();
2144 TypeUnitsUnderConstruction.push_back(
2145 std::make_pair(std::move(OwnedUnit), CTy));
2147 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2150 uint64_t Signature = makeTypeSignature(Identifier);
2151 NewTU.setTypeSignature(Signature);
2153 if (useSplitDwarf())
2154 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2155 DwarfTypesDWOSectionSym);
2157 CU.applyStmtList(UnitDie);
2159 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2162 NewTU.setType(NewTU.createTypeDIE(CTy));
2165 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2166 TypeUnitsUnderConstruction.clear();
2168 // Types referencing entries in the address table cannot be placed in type
2170 if (AddrPool.hasBeenUsed()) {
2172 // Remove all the types built while building this type.
2173 // This is pessimistic as some of these types might not be dependent on
2174 // the type that used an address.
2175 for (const auto &TU : TypeUnitsToAdd)
2176 DwarfTypeUnits.erase(TU.second);
2178 // Construct this type in the CU directly.
2179 // This is inefficient because all the dependent types will be rebuilt
2180 // from scratch, including building them in type units, discovering that
2181 // they depend on addresses, throwing them out and rebuilding them.
2182 CU.constructTypeDIE(RefDie, CTy);
2186 // If the type wasn't dependent on fission addresses, finish adding the type
2187 // and all its dependent types.
2188 for (auto &TU : TypeUnitsToAdd)
2189 InfoHolder.addUnit(std::move(TU.first));
2191 CU.addDIETypeSignature(RefDie, NewTU);
2194 // Accelerator table mutators - add each name along with its companion
2195 // DIE to the proper table while ensuring that the name that we're going
2196 // to reference is in the string table. We do this since the names we
2197 // add may not only be identical to the names in the DIE.
2198 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2199 if (!useDwarfAccelTables())
2201 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2205 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2206 if (!useDwarfAccelTables())
2208 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2212 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2213 if (!useDwarfAccelTables())
2215 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2219 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2220 if (!useDwarfAccelTables())
2222 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),