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 &TheU : getUnits()) {
545 // Emit DW_AT_containing_type attribute to connect types with their
546 // vtable holding type.
547 TheU->constructContainingTypeDIEs();
549 // Add CU specific attributes if we need to add any.
550 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
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 DwarfCompileUnit *SkCU =
554 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
555 if (useSplitDwarf()) {
556 // Emit a unique identifier for this CU.
557 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
558 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
559 dwarf::DW_FORM_data8, ID);
560 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
561 dwarf::DW_FORM_data8, ID);
563 // We don't keep track of which addresses are used in which CU so this
564 // is a bit pessimistic under LTO.
565 if (!AddrPool.isEmpty())
566 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
567 DwarfAddrSectionSym, DwarfAddrSectionSym);
568 if (!TheU->getRangeLists().empty())
569 SkCU->addSectionLabel(
570 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
571 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
574 // If we have code split among multiple sections or non-contiguous
575 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
576 // remain in the .o file, otherwise add a DW_AT_low_pc.
577 // FIXME: We should use ranges allow reordering of code ala
578 // .subsections_via_symbols in mach-o. This would mean turning on
579 // ranges for all subprogram DIEs for mach-o.
580 DwarfCompileUnit &U =
581 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
582 unsigned NumRanges = TheU->getRanges().size();
585 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
586 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
587 DwarfDebugRangeSectionSym);
589 // A DW_AT_low_pc attribute may also be specified in combination with
590 // DW_AT_ranges to specify the default base address for use in
591 // location lists (see Section 2.6.2) and range lists (see Section
593 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
596 RangeSpan &Range = TheU->getRanges().back();
597 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
603 // Compute DIE offsets and sizes.
604 InfoHolder.computeSizeAndOffsets();
606 SkeletonHolder.computeSizeAndOffsets();
609 void DwarfDebug::endSections() {
610 // Filter labels by section.
611 for (const SymbolCU &SCU : ArangeLabels) {
612 if (SCU.Sym->isInSection()) {
613 // Make a note of this symbol and it's section.
614 const MCSection *Section = &SCU.Sym->getSection();
615 if (!Section->getKind().isMetadata())
616 SectionMap[Section].push_back(SCU);
618 // Some symbols (e.g. common/bss on mach-o) can have no section but still
619 // appear in the output. This sucks as we rely on sections to build
620 // arange spans. We can do it without, but it's icky.
621 SectionMap[nullptr].push_back(SCU);
625 // Build a list of sections used.
626 std::vector<const MCSection *> Sections;
627 for (const auto &it : SectionMap) {
628 const MCSection *Section = it.first;
629 Sections.push_back(Section);
632 // Sort the sections into order.
633 // This is only done to ensure consistent output order across different runs.
634 std::sort(Sections.begin(), Sections.end(), SectionSort);
636 // Add terminating symbols for each section.
637 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
638 const MCSection *Section = Sections[ID];
639 MCSymbol *Sym = nullptr;
642 // We can't call MCSection::getLabelEndName, as it's only safe to do so
643 // if we know the section name up-front. For user-created sections, the
644 // resulting label may not be valid to use as a label. (section names can
645 // use a greater set of characters on some systems)
646 Sym = Asm->GetTempSymbol("debug_end", ID);
647 Asm->OutStreamer.SwitchSection(Section);
648 Asm->OutStreamer.EmitLabel(Sym);
651 // Insert a final terminator.
652 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
656 // Emit all Dwarf sections that should come after the content.
657 void DwarfDebug::endModule() {
658 assert(CurFn == nullptr);
659 assert(CurMI == nullptr);
661 // If we aren't actually generating debug info (check beginModule -
662 // conditionalized on !DisableDebugInfoPrinting and the presence of the
663 // llvm.dbg.cu metadata node)
664 if (!DwarfInfoSectionSym)
667 // End any existing sections.
668 // TODO: Does this need to happen?
671 // Finalize the debug info for the module.
672 finalizeModuleInfo();
676 // Emit all the DIEs into a debug info section.
679 // Corresponding abbreviations into a abbrev section.
682 // Emit info into a debug aranges section.
683 if (GenerateARangeSection)
686 // Emit info into a debug ranges section.
689 if (useSplitDwarf()) {
692 emitDebugAbbrevDWO();
695 // Emit DWO addresses.
696 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
698 // Emit info into a debug loc section.
701 // Emit info into the dwarf accelerator table sections.
702 if (useDwarfAccelTables()) {
705 emitAccelNamespaces();
709 // Emit the pubnames and pubtypes sections if requested.
710 if (HasDwarfPubSections) {
711 emitDebugPubNames(GenerateGnuPubSections);
712 emitDebugPubTypes(GenerateGnuPubSections);
717 AbstractVariables.clear();
720 // Find abstract variable, if any, associated with Var.
721 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
722 DIVariable &Cleansed) {
723 LLVMContext &Ctx = DV->getContext();
724 // More then one inlined variable corresponds to one abstract variable.
725 // FIXME: This duplication of variables when inlining should probably be
726 // removed. It's done to allow each DIVariable to describe its location
727 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
728 // make it accurate then remove this duplication/cleansing stuff.
729 Cleansed = cleanseInlinedVariable(DV, Ctx);
730 auto I = AbstractVariables.find(Cleansed);
731 if (I != AbstractVariables.end())
732 return I->second.get();
736 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
738 return getExistingAbstractVariable(DV, Cleansed);
741 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
742 LexicalScope *Scope) {
743 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
744 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
745 AbstractVariables[Var] = std::move(AbsDbgVariable);
748 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
749 const MDNode *ScopeNode) {
750 DIVariable Cleansed = DV;
751 if (getExistingAbstractVariable(DV, Cleansed))
754 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
758 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
759 const MDNode *ScopeNode) {
760 DIVariable Cleansed = DV;
761 if (getExistingAbstractVariable(DV, Cleansed))
764 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
765 createAbstractVariable(Cleansed, Scope);
768 // Collect variable information from side table maintained by MMI.
769 void DwarfDebug::collectVariableInfoFromMMITable(
770 SmallPtrSetImpl<const MDNode *> &Processed) {
771 for (const auto &VI : MMI->getVariableDbgInfo()) {
774 Processed.insert(VI.Var);
775 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
777 // If variable scope is not found then skip this variable.
781 DIVariable DV(VI.Var);
782 DIExpression Expr(VI.Expr);
783 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
784 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
785 DbgVariable *RegVar = ConcreteVariables.back().get();
786 RegVar->setFrameIndex(VI.Slot);
787 InfoHolder.addScopeVariable(Scope, RegVar);
791 // Get .debug_loc entry for the instruction range starting at MI.
792 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
793 const MDNode *Expr = MI->getDebugExpression();
794 const MDNode *Var = MI->getDebugVariable();
796 assert(MI->getNumOperands() == 4);
797 if (MI->getOperand(0).isReg()) {
798 MachineLocation MLoc;
799 // If the second operand is an immediate, this is a
800 // register-indirect address.
801 if (!MI->getOperand(1).isImm())
802 MLoc.set(MI->getOperand(0).getReg());
804 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
805 return DebugLocEntry::Value(Var, Expr, MLoc);
807 if (MI->getOperand(0).isImm())
808 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
809 if (MI->getOperand(0).isFPImm())
810 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
811 if (MI->getOperand(0).isCImm())
812 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
814 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
817 /// Determine whether two variable pieces overlap.
818 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
819 if (!P1.isVariablePiece() || !P2.isVariablePiece())
821 unsigned l1 = P1.getPieceOffset();
822 unsigned l2 = P2.getPieceOffset();
823 unsigned r1 = l1 + P1.getPieceSize();
824 unsigned r2 = l2 + P2.getPieceSize();
825 // True where [l1,r1[ and [r1,r2[ overlap.
826 return (l1 < r2) && (l2 < r1);
829 /// Build the location list for all DBG_VALUEs in the function that
830 /// describe the same variable. If the ranges of several independent
831 /// pieces of the same variable overlap partially, split them up and
832 /// combine the ranges. The resulting DebugLocEntries are will have
833 /// strict monotonically increasing begin addresses and will never
838 // Ranges History [var, loc, piece ofs size]
839 // 0 | [x, (reg0, piece 0, 32)]
840 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
842 // 3 | [clobber reg0]
843 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
847 // [0-1] [x, (reg0, piece 0, 32)]
848 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
849 // [3-4] [x, (reg1, piece 32, 32)]
850 // [4- ] [x, (mem, piece 0, 64)]
852 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
853 const DbgValueHistoryMap::InstrRanges &Ranges) {
854 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
856 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
857 const MachineInstr *Begin = I->first;
858 const MachineInstr *End = I->second;
859 assert(Begin->isDebugValue() && "Invalid History entry");
861 // Check if a variable is inaccessible in this range.
862 if (Begin->getNumOperands() > 1 &&
863 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
868 // If this piece overlaps with any open ranges, truncate them.
869 DIExpression DIExpr = Begin->getDebugExpression();
870 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
871 [&](DebugLocEntry::Value R) {
872 return piecesOverlap(DIExpr, R.getExpression());
874 OpenRanges.erase(Last, OpenRanges.end());
876 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
877 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
879 const MCSymbol *EndLabel;
881 EndLabel = getLabelAfterInsn(End);
882 else if (std::next(I) == Ranges.end())
883 EndLabel = FunctionEndSym;
885 EndLabel = getLabelBeforeInsn(std::next(I)->first);
886 assert(EndLabel && "Forgot label after instruction ending a range!");
888 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
890 auto Value = getDebugLocValue(Begin);
891 DebugLocEntry Loc(StartLabel, EndLabel, Value);
892 bool couldMerge = false;
894 // If this is a piece, it may belong to the current DebugLocEntry.
895 if (DIExpr.isVariablePiece()) {
896 // Add this value to the list of open ranges.
897 OpenRanges.push_back(Value);
899 // Attempt to add the piece to the last entry.
900 if (!DebugLoc.empty())
901 if (DebugLoc.back().MergeValues(Loc))
906 // Need to add a new DebugLocEntry. Add all values from still
907 // valid non-overlapping pieces.
908 if (OpenRanges.size())
909 Loc.addValues(OpenRanges);
911 DebugLoc.push_back(std::move(Loc));
914 // Attempt to coalesce the ranges of two otherwise identical
916 auto CurEntry = DebugLoc.rbegin();
917 auto PrevEntry = std::next(CurEntry);
918 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
922 dbgs() << CurEntry->getValues().size() << " Values:\n";
923 for (auto Value : CurEntry->getValues()) {
924 Value.getVariable()->dump();
925 Value.getExpression()->dump();
933 // Find variables for each lexical scope.
935 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
936 SmallPtrSetImpl<const MDNode *> &Processed) {
937 // Grab the variable info that was squirreled away in the MMI side-table.
938 collectVariableInfoFromMMITable(Processed);
940 for (const auto &I : DbgValues) {
941 DIVariable DV(I.first);
942 if (Processed.count(DV))
945 // Instruction ranges, specifying where DV is accessible.
946 const auto &Ranges = I.second;
950 LexicalScope *Scope = nullptr;
951 if (MDNode *IA = DV.getInlinedAt()) {
952 DebugLoc DL = DebugLoc::getFromDILocation(IA);
953 Scope = LScopes.findInlinedScope(DebugLoc::get(
954 DL.getLine(), DL.getCol(), DV.getContext(), IA));
956 Scope = LScopes.findLexicalScope(DV.getContext());
957 // If variable scope is not found then skip this variable.
961 Processed.insert(DV);
962 const MachineInstr *MInsn = Ranges.front().first;
963 assert(MInsn->isDebugValue() && "History must begin with debug value");
964 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
965 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
966 DbgVariable *RegVar = ConcreteVariables.back().get();
967 InfoHolder.addScopeVariable(Scope, RegVar);
969 // Check if the first DBG_VALUE is valid for the rest of the function.
970 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
973 // Handle multiple DBG_VALUE instructions describing one variable.
974 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
976 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
977 DebugLocList &LocList = DotDebugLocEntries.back();
980 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
982 // Build the location list for this variable.
983 buildLocationList(LocList.List, Ranges);
986 // Collect info for variables that were optimized out.
987 DIArray Variables = SP.getVariables();
988 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
989 DIVariable DV(Variables.getElement(i));
990 assert(DV.isVariable());
991 if (!Processed.insert(DV))
993 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
994 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
996 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
997 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1002 // Return Label preceding the instruction.
1003 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1004 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1005 assert(Label && "Didn't insert label before instruction");
1009 // Return Label immediately following the instruction.
1010 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1011 return LabelsAfterInsn.lookup(MI);
1014 // Process beginning of an instruction.
1015 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1016 assert(CurMI == nullptr);
1018 // Check if source location changes, but ignore DBG_VALUE locations.
1019 if (!MI->isDebugValue()) {
1020 DebugLoc DL = MI->getDebugLoc();
1021 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1024 if (DL == PrologEndLoc) {
1025 Flags |= DWARF2_FLAG_PROLOGUE_END;
1026 PrologEndLoc = DebugLoc();
1028 if (PrologEndLoc.isUnknown())
1029 Flags |= DWARF2_FLAG_IS_STMT;
1031 if (!DL.isUnknown()) {
1032 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1033 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1035 recordSourceLine(0, 0, nullptr, 0);
1039 // Insert labels where requested.
1040 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1041 LabelsBeforeInsn.find(MI);
1044 if (I == LabelsBeforeInsn.end())
1047 // Label already assigned.
1052 PrevLabel = MMI->getContext().CreateTempSymbol();
1053 Asm->OutStreamer.EmitLabel(PrevLabel);
1055 I->second = PrevLabel;
1058 // Process end of an instruction.
1059 void DwarfDebug::endInstruction() {
1060 assert(CurMI != nullptr);
1061 // Don't create a new label after DBG_VALUE instructions.
1062 // They don't generate code.
1063 if (!CurMI->isDebugValue())
1064 PrevLabel = nullptr;
1066 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1067 LabelsAfterInsn.find(CurMI);
1071 if (I == LabelsAfterInsn.end())
1074 // Label already assigned.
1078 // We need a label after this instruction.
1080 PrevLabel = MMI->getContext().CreateTempSymbol();
1081 Asm->OutStreamer.EmitLabel(PrevLabel);
1083 I->second = PrevLabel;
1086 // Each LexicalScope has first instruction and last instruction to mark
1087 // beginning and end of a scope respectively. Create an inverse map that list
1088 // scopes starts (and ends) with an instruction. One instruction may start (or
1089 // end) multiple scopes. Ignore scopes that are not reachable.
1090 void DwarfDebug::identifyScopeMarkers() {
1091 SmallVector<LexicalScope *, 4> WorkList;
1092 WorkList.push_back(LScopes.getCurrentFunctionScope());
1093 while (!WorkList.empty()) {
1094 LexicalScope *S = WorkList.pop_back_val();
1096 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1097 if (!Children.empty())
1098 WorkList.append(Children.begin(), Children.end());
1100 if (S->isAbstractScope())
1103 for (const InsnRange &R : S->getRanges()) {
1104 assert(R.first && "InsnRange does not have first instruction!");
1105 assert(R.second && "InsnRange does not have second instruction!");
1106 requestLabelBeforeInsn(R.first);
1107 requestLabelAfterInsn(R.second);
1112 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1113 // First known non-DBG_VALUE and non-frame setup location marks
1114 // the beginning of the function body.
1115 for (const auto &MBB : *MF)
1116 for (const auto &MI : MBB)
1117 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1118 !MI.getDebugLoc().isUnknown())
1119 return MI.getDebugLoc();
1123 // Gather pre-function debug information. Assumes being called immediately
1124 // after the function entry point has been emitted.
1125 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1128 // If there's no debug info for the function we're not going to do anything.
1129 if (!MMI->hasDebugInfo())
1132 auto DI = FunctionDIs.find(MF->getFunction());
1133 if (DI == FunctionDIs.end())
1136 // Grab the lexical scopes for the function, if we don't have any of those
1137 // then we're not going to be able to do anything.
1138 LScopes.initialize(*MF);
1139 if (LScopes.empty())
1142 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1144 // Make sure that each lexical scope will have a begin/end label.
1145 identifyScopeMarkers();
1147 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1148 // belongs to so that we add to the correct per-cu line table in the
1150 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1151 // FnScope->getScopeNode() and DI->second should represent the same function,
1152 // though they may not be the same MDNode due to inline functions merged in
1153 // LTO where the debug info metadata still differs (either due to distinct
1154 // written differences - two versions of a linkonce_odr function
1155 // written/copied into two separate files, or some sub-optimal metadata that
1156 // isn't structurally identical (see: file path/name info from clang, which
1157 // includes the directory of the cpp file being built, even when the file name
1158 // is absolute (such as an <> lookup header)))
1159 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1160 assert(TheCU && "Unable to find compile unit!");
1161 if (Asm->OutStreamer.hasRawTextSupport())
1162 // Use a single line table if we are generating assembly.
1163 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1165 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1167 // Emit a label for the function so that we have a beginning address.
1168 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1169 // Assumes in correct section after the entry point.
1170 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1172 // Calculate history for local variables.
1173 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1176 // Request labels for the full history.
1177 for (const auto &I : DbgValues) {
1178 const auto &Ranges = I.second;
1182 // The first mention of a function argument gets the FunctionBeginSym
1183 // label, so arguments are visible when breaking at function entry.
1184 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1185 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1186 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1187 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1188 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1189 // Mark all non-overlapping initial pieces.
1190 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1191 DIExpression Piece = I->first->getDebugExpression();
1192 if (std::all_of(Ranges.begin(), I,
1193 [&](DbgValueHistoryMap::InstrRange Pred) {
1194 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1196 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1203 for (const auto &Range : Ranges) {
1204 requestLabelBeforeInsn(Range.first);
1206 requestLabelAfterInsn(Range.second);
1210 PrevInstLoc = DebugLoc();
1211 PrevLabel = FunctionBeginSym;
1213 // Record beginning of function.
1214 PrologEndLoc = findPrologueEndLoc(MF);
1215 if (!PrologEndLoc.isUnknown()) {
1216 DebugLoc FnStartDL =
1217 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1219 FnStartDL.getLine(), FnStartDL.getCol(),
1220 FnStartDL.getScope(MF->getFunction()->getContext()),
1221 // We'd like to list the prologue as "not statements" but GDB behaves
1222 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1223 DWARF2_FLAG_IS_STMT);
1227 // Gather and emit post-function debug information.
1228 void DwarfDebug::endFunction(const MachineFunction *MF) {
1229 assert(CurFn == MF &&
1230 "endFunction should be called with the same function as beginFunction");
1232 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1233 !FunctionDIs.count(MF->getFunction())) {
1234 // If we don't have a lexical scope for this function then there will
1235 // be a hole in the range information. Keep note of this by setting the
1236 // previously used section to nullptr.
1242 // Define end label for subprogram.
1243 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1244 // Assumes in correct section after the entry point.
1245 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1247 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1248 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1250 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1251 DISubprogram SP(FnScope->getScopeNode());
1252 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1254 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1255 collectVariableInfo(TheCU, SP, ProcessedVars);
1257 // Add the range of this function to the list of ranges for the CU.
1258 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1260 // Under -gmlt, skip building the subprogram if there are no inlined
1261 // subroutines inside it.
1262 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1263 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1264 assert(InfoHolder.getScopeVariables().empty());
1265 assert(DbgValues.empty());
1266 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1267 // by a -gmlt CU. Add a test and remove this assertion.
1268 assert(AbstractVariables.empty());
1269 LabelsBeforeInsn.clear();
1270 LabelsAfterInsn.clear();
1271 PrevLabel = nullptr;
1277 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1279 // Construct abstract scopes.
1280 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1281 DISubprogram SP(AScope->getScopeNode());
1282 assert(SP.isSubprogram());
1283 // Collect info for variables that were optimized out.
1284 DIArray Variables = SP.getVariables();
1285 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1286 DIVariable DV(Variables.getElement(i));
1287 assert(DV && DV.isVariable());
1288 if (!ProcessedVars.insert(DV))
1290 ensureAbstractVariableIsCreated(DV, DV.getContext());
1291 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1292 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1294 constructAbstractSubprogramScopeDIE(AScope);
1297 TheCU.constructSubprogramScopeDIE(FnScope);
1300 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1301 // DbgVariables except those that are also in AbstractVariables (since they
1302 // can be used cross-function)
1303 InfoHolder.getScopeVariables().clear();
1305 LabelsBeforeInsn.clear();
1306 LabelsAfterInsn.clear();
1307 PrevLabel = nullptr;
1311 // Register a source line with debug info. Returns the unique label that was
1312 // emitted and which provides correspondence to the source line list.
1313 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1318 unsigned Discriminator = 0;
1319 if (DIScope Scope = DIScope(S)) {
1320 assert(Scope.isScope());
1321 Fn = Scope.getFilename();
1322 Dir = Scope.getDirectory();
1323 if (Scope.isLexicalBlockFile())
1324 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1326 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1327 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1328 .getOrCreateSourceID(Fn, Dir);
1330 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1334 //===----------------------------------------------------------------------===//
1336 //===----------------------------------------------------------------------===//
1338 // Emit initial Dwarf sections with a label at the start of each one.
1339 void DwarfDebug::emitSectionLabels() {
1340 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1342 // Dwarf sections base addresses.
1343 DwarfInfoSectionSym =
1344 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1345 if (useSplitDwarf()) {
1346 DwarfInfoDWOSectionSym =
1347 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1348 DwarfTypesDWOSectionSym =
1349 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1351 DwarfAbbrevSectionSym =
1352 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1353 if (useSplitDwarf())
1354 DwarfAbbrevDWOSectionSym = emitSectionSym(
1355 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1356 if (GenerateARangeSection)
1357 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1359 DwarfLineSectionSym =
1360 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1361 if (GenerateGnuPubSections) {
1362 DwarfGnuPubNamesSectionSym =
1363 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1364 DwarfGnuPubTypesSectionSym =
1365 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1366 } else if (HasDwarfPubSections) {
1367 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1368 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1371 DwarfStrSectionSym =
1372 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1373 if (useSplitDwarf()) {
1374 DwarfStrDWOSectionSym =
1375 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1376 DwarfAddrSectionSym =
1377 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1378 DwarfDebugLocSectionSym =
1379 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1381 DwarfDebugLocSectionSym =
1382 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1383 DwarfDebugRangeSectionSym =
1384 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1387 // Recursively emits a debug information entry.
1388 void DwarfDebug::emitDIE(DIE &Die) {
1389 // Get the abbreviation for this DIE.
1390 const DIEAbbrev &Abbrev = Die.getAbbrev();
1392 // Emit the code (index) for the abbreviation.
1393 if (Asm->isVerbose())
1394 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1395 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1396 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1397 dwarf::TagString(Abbrev.getTag()));
1398 Asm->EmitULEB128(Abbrev.getNumber());
1400 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1401 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1403 // Emit the DIE attribute values.
1404 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1405 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1406 dwarf::Form Form = AbbrevData[i].getForm();
1407 assert(Form && "Too many attributes for DIE (check abbreviation)");
1409 if (Asm->isVerbose()) {
1410 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1411 if (Attr == dwarf::DW_AT_accessibility)
1412 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1413 cast<DIEInteger>(Values[i])->getValue()));
1416 // Emit an attribute using the defined form.
1417 Values[i]->EmitValue(Asm, Form);
1420 // Emit the DIE children if any.
1421 if (Abbrev.hasChildren()) {
1422 for (auto &Child : Die.getChildren())
1425 Asm->OutStreamer.AddComment("End Of Children Mark");
1430 // Emit the debug info section.
1431 void DwarfDebug::emitDebugInfo() {
1432 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1434 Holder.emitUnits(DwarfAbbrevSectionSym);
1437 // Emit the abbreviation section.
1438 void DwarfDebug::emitAbbreviations() {
1439 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1441 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1444 // Emit the last address of the section and the end of the line matrix.
1445 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1446 // Define last address of section.
1447 Asm->OutStreamer.AddComment("Extended Op");
1450 Asm->OutStreamer.AddComment("Op size");
1451 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1452 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1453 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1455 Asm->OutStreamer.AddComment("Section end label");
1457 Asm->OutStreamer.EmitSymbolValue(
1458 Asm->GetTempSymbol("section_end", SectionEnd),
1459 Asm->getDataLayout().getPointerSize());
1461 // Mark end of matrix.
1462 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1468 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1469 StringRef TableName, StringRef SymName) {
1470 Accel.FinalizeTable(Asm, TableName);
1471 Asm->OutStreamer.SwitchSection(Section);
1472 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1473 Asm->OutStreamer.EmitLabel(SectionBegin);
1475 // Emit the full data.
1476 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1479 // Emit visible names into a hashed accelerator table section.
1480 void DwarfDebug::emitAccelNames() {
1481 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1482 "Names", "names_begin");
1485 // Emit objective C classes and categories into a hashed accelerator table
1487 void DwarfDebug::emitAccelObjC() {
1488 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1489 "ObjC", "objc_begin");
1492 // Emit namespace dies into a hashed accelerator table.
1493 void DwarfDebug::emitAccelNamespaces() {
1494 emitAccel(AccelNamespace,
1495 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1496 "namespac", "namespac_begin");
1499 // Emit type dies into a hashed accelerator table.
1500 void DwarfDebug::emitAccelTypes() {
1501 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1502 "types", "types_begin");
1505 // Public name handling.
1506 // The format for the various pubnames:
1508 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1509 // for the DIE that is named.
1511 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1512 // into the CU and the index value is computed according to the type of value
1513 // for the DIE that is named.
1515 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1516 // it's the offset within the debug_info/debug_types dwo section, however, the
1517 // reference in the pubname header doesn't change.
1519 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1520 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1522 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1524 // We could have a specification DIE that has our most of our knowledge,
1525 // look for that now.
1526 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1528 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1529 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1530 Linkage = dwarf::GIEL_EXTERNAL;
1531 } else if (Die->findAttribute(dwarf::DW_AT_external))
1532 Linkage = dwarf::GIEL_EXTERNAL;
1534 switch (Die->getTag()) {
1535 case dwarf::DW_TAG_class_type:
1536 case dwarf::DW_TAG_structure_type:
1537 case dwarf::DW_TAG_union_type:
1538 case dwarf::DW_TAG_enumeration_type:
1539 return dwarf::PubIndexEntryDescriptor(
1540 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1541 ? dwarf::GIEL_STATIC
1542 : dwarf::GIEL_EXTERNAL);
1543 case dwarf::DW_TAG_typedef:
1544 case dwarf::DW_TAG_base_type:
1545 case dwarf::DW_TAG_subrange_type:
1546 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1547 case dwarf::DW_TAG_namespace:
1548 return dwarf::GIEK_TYPE;
1549 case dwarf::DW_TAG_subprogram:
1550 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1551 case dwarf::DW_TAG_constant:
1552 case dwarf::DW_TAG_variable:
1553 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1554 case dwarf::DW_TAG_enumerator:
1555 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1556 dwarf::GIEL_STATIC);
1558 return dwarf::GIEK_NONE;
1562 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1564 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1565 const MCSection *PSec =
1566 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1567 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1569 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1572 void DwarfDebug::emitDebugPubSection(
1573 bool GnuStyle, const MCSection *PSec, StringRef Name,
1574 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1575 for (const auto &NU : CUMap) {
1576 DwarfCompileUnit *TheU = NU.second;
1578 const auto &Globals = (TheU->*Accessor)();
1580 if (Globals.empty())
1583 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1585 unsigned ID = TheU->getUniqueID();
1587 // Start the dwarf pubnames section.
1588 Asm->OutStreamer.SwitchSection(PSec);
1591 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1592 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1593 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1594 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1596 Asm->OutStreamer.EmitLabel(BeginLabel);
1598 Asm->OutStreamer.AddComment("DWARF Version");
1599 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1601 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1602 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1604 Asm->OutStreamer.AddComment("Compilation Unit Length");
1605 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1607 // Emit the pubnames for this compilation unit.
1608 for (const auto &GI : Globals) {
1609 const char *Name = GI.getKeyData();
1610 const DIE *Entity = GI.second;
1612 Asm->OutStreamer.AddComment("DIE offset");
1613 Asm->EmitInt32(Entity->getOffset());
1616 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1617 Asm->OutStreamer.AddComment(
1618 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1619 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1620 Asm->EmitInt8(Desc.toBits());
1623 Asm->OutStreamer.AddComment("External Name");
1624 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1627 Asm->OutStreamer.AddComment("End Mark");
1629 Asm->OutStreamer.EmitLabel(EndLabel);
1633 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1634 const MCSection *PSec =
1635 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1636 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1638 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1641 // Emit visible names into a debug str section.
1642 void DwarfDebug::emitDebugStr() {
1643 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1644 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1647 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1648 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1649 const DITypeIdentifierMap &Map,
1650 ArrayRef<DebugLocEntry::Value> Values) {
1651 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1652 return P.isVariablePiece();
1653 }) && "all values are expected to be pieces");
1654 assert(std::is_sorted(Values.begin(), Values.end()) &&
1655 "pieces are expected to be sorted");
1657 unsigned Offset = 0;
1658 for (auto Piece : Values) {
1659 DIExpression Expr = Piece.getExpression();
1660 unsigned PieceOffset = Expr.getPieceOffset();
1661 unsigned PieceSize = Expr.getPieceSize();
1662 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1663 if (Offset < PieceOffset) {
1664 // The DWARF spec seriously mandates pieces with no locations for gaps.
1665 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1666 Offset += PieceOffset-Offset;
1669 Offset += PieceSize;
1671 const unsigned SizeOfByte = 8;
1673 DIVariable Var = Piece.getVariable();
1674 assert(!Var.isIndirect() && "indirect address for piece");
1675 unsigned VarSize = Var.getSizeInBits(Map);
1676 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1677 && "piece is larger than or outside of variable");
1678 assert(PieceSize*SizeOfByte != VarSize
1679 && "piece covers entire variable");
1681 if (Piece.isLocation() && Piece.getLoc().isReg())
1682 Asm->EmitDwarfRegOpPiece(Streamer,
1684 PieceSize*SizeOfByte);
1686 emitDebugLocValue(Streamer, Piece);
1687 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1693 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1694 const DebugLocEntry &Entry) {
1695 const DebugLocEntry::Value Value = Entry.getValues()[0];
1696 if (Value.isVariablePiece())
1697 // Emit all pieces that belong to the same variable and range.
1698 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1700 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1701 emitDebugLocValue(Streamer, Value);
1704 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1705 const DebugLocEntry::Value &Value) {
1706 DIVariable DV = Value.getVariable();
1708 if (Value.isInt()) {
1709 DIBasicType BTy(resolve(DV.getType()));
1710 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1711 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1712 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1713 Streamer.EmitSLEB128(Value.getInt());
1715 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1716 Streamer.EmitULEB128(Value.getInt());
1718 } else if (Value.isLocation()) {
1719 MachineLocation Loc = Value.getLoc();
1720 DIExpression Expr = Value.getExpression();
1723 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1725 // Complex address entry.
1726 unsigned N = Expr.getNumElements();
1728 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1729 if (Loc.getOffset()) {
1731 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1732 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1733 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1734 Streamer.EmitSLEB128(Expr.getElement(1));
1736 // If first address element is OpPlus then emit
1737 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1738 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1739 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1743 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1746 // Emit remaining complex address elements.
1747 for (; i < N; ++i) {
1748 uint64_t Element = Expr.getElement(i);
1749 if (Element == dwarf::DW_OP_plus) {
1750 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1751 Streamer.EmitULEB128(Expr.getElement(++i));
1752 } else if (Element == dwarf::DW_OP_deref) {
1754 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1755 } else if (Element == dwarf::DW_OP_piece) {
1757 // handled in emitDebugLocEntry.
1759 llvm_unreachable("unknown Opcode found in complex address");
1763 // else ... ignore constant fp. There is not any good way to
1764 // to represent them here in dwarf.
1768 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1769 Asm->OutStreamer.AddComment("Loc expr size");
1770 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1771 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1772 Asm->EmitLabelDifference(end, begin, 2);
1773 Asm->OutStreamer.EmitLabel(begin);
1775 APByteStreamer Streamer(*Asm);
1776 emitDebugLocEntry(Streamer, Entry);
1778 Asm->OutStreamer.EmitLabel(end);
1781 // Emit locations into the debug loc section.
1782 void DwarfDebug::emitDebugLoc() {
1783 // Start the dwarf loc section.
1784 Asm->OutStreamer.SwitchSection(
1785 Asm->getObjFileLowering().getDwarfLocSection());
1786 unsigned char Size = Asm->getDataLayout().getPointerSize();
1787 for (const auto &DebugLoc : DotDebugLocEntries) {
1788 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1789 const DwarfCompileUnit *CU = DebugLoc.CU;
1790 assert(!CU->getRanges().empty());
1791 for (const auto &Entry : DebugLoc.List) {
1792 // Set up the range. This range is relative to the entry point of the
1793 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1794 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1795 if (CU->getRanges().size() == 1) {
1796 // Grab the begin symbol from the first range as our base.
1797 const MCSymbol *Base = CU->getRanges()[0].getStart();
1798 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1799 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1801 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1802 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1805 emitDebugLocEntryLocation(Entry);
1807 Asm->OutStreamer.EmitIntValue(0, Size);
1808 Asm->OutStreamer.EmitIntValue(0, Size);
1812 void DwarfDebug::emitDebugLocDWO() {
1813 Asm->OutStreamer.SwitchSection(
1814 Asm->getObjFileLowering().getDwarfLocDWOSection());
1815 for (const auto &DebugLoc : DotDebugLocEntries) {
1816 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1817 for (const auto &Entry : DebugLoc.List) {
1818 // Just always use start_length for now - at least that's one address
1819 // rather than two. We could get fancier and try to, say, reuse an
1820 // address we know we've emitted elsewhere (the start of the function?
1821 // The start of the CU or CU subrange that encloses this range?)
1822 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1823 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1824 Asm->EmitULEB128(idx);
1825 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1827 emitDebugLocEntryLocation(Entry);
1829 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1834 const MCSymbol *Start, *End;
1837 // Emit a debug aranges section, containing a CU lookup for any
1838 // address we can tie back to a CU.
1839 void DwarfDebug::emitDebugARanges() {
1840 // Start the dwarf aranges section.
1841 Asm->OutStreamer.SwitchSection(
1842 Asm->getObjFileLowering().getDwarfARangesSection());
1844 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1848 // Build a list of sections used.
1849 std::vector<const MCSection *> Sections;
1850 for (const auto &it : SectionMap) {
1851 const MCSection *Section = it.first;
1852 Sections.push_back(Section);
1855 // Sort the sections into order.
1856 // This is only done to ensure consistent output order across different runs.
1857 std::sort(Sections.begin(), Sections.end(), SectionSort);
1859 // Build a set of address spans, sorted by CU.
1860 for (const MCSection *Section : Sections) {
1861 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1862 if (List.size() < 2)
1865 // Sort the symbols by offset within the section.
1866 std::sort(List.begin(), List.end(),
1867 [&](const SymbolCU &A, const SymbolCU &B) {
1868 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1869 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1871 // Symbols with no order assigned should be placed at the end.
1872 // (e.g. section end labels)
1880 // If we have no section (e.g. common), just write out
1881 // individual spans for each symbol.
1883 for (const SymbolCU &Cur : List) {
1885 Span.Start = Cur.Sym;
1888 Spans[Cur.CU].push_back(Span);
1891 // Build spans between each label.
1892 const MCSymbol *StartSym = List[0].Sym;
1893 for (size_t n = 1, e = List.size(); n < e; n++) {
1894 const SymbolCU &Prev = List[n - 1];
1895 const SymbolCU &Cur = List[n];
1897 // Try and build the longest span we can within the same CU.
1898 if (Cur.CU != Prev.CU) {
1900 Span.Start = StartSym;
1902 Spans[Prev.CU].push_back(Span);
1909 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1911 // Build a list of CUs used.
1912 std::vector<DwarfCompileUnit *> CUs;
1913 for (const auto &it : Spans) {
1914 DwarfCompileUnit *CU = it.first;
1918 // Sort the CU list (again, to ensure consistent output order).
1919 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1920 return A->getUniqueID() < B->getUniqueID();
1923 // Emit an arange table for each CU we used.
1924 for (DwarfCompileUnit *CU : CUs) {
1925 std::vector<ArangeSpan> &List = Spans[CU];
1927 // Emit size of content not including length itself.
1928 unsigned ContentSize =
1929 sizeof(int16_t) + // DWARF ARange version number
1930 sizeof(int32_t) + // Offset of CU in the .debug_info section
1931 sizeof(int8_t) + // Pointer Size (in bytes)
1932 sizeof(int8_t); // Segment Size (in bytes)
1934 unsigned TupleSize = PtrSize * 2;
1936 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1938 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1940 ContentSize += Padding;
1941 ContentSize += (List.size() + 1) * TupleSize;
1943 // For each compile unit, write the list of spans it covers.
1944 Asm->OutStreamer.AddComment("Length of ARange Set");
1945 Asm->EmitInt32(ContentSize);
1946 Asm->OutStreamer.AddComment("DWARF Arange version number");
1947 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1948 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1949 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1950 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1951 Asm->EmitInt8(PtrSize);
1952 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1955 Asm->OutStreamer.EmitFill(Padding, 0xff);
1957 for (const ArangeSpan &Span : List) {
1958 Asm->EmitLabelReference(Span.Start, PtrSize);
1960 // Calculate the size as being from the span start to it's end.
1962 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1964 // For symbols without an end marker (e.g. common), we
1965 // write a single arange entry containing just that one symbol.
1966 uint64_t Size = SymSize[Span.Start];
1970 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1974 Asm->OutStreamer.AddComment("ARange terminator");
1975 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1976 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1980 // Emit visible names into a debug ranges section.
1981 void DwarfDebug::emitDebugRanges() {
1982 // Start the dwarf ranges section.
1983 Asm->OutStreamer.SwitchSection(
1984 Asm->getObjFileLowering().getDwarfRangesSection());
1986 // Size for our labels.
1987 unsigned char Size = Asm->getDataLayout().getPointerSize();
1989 // Grab the specific ranges for the compile units in the module.
1990 for (const auto &I : CUMap) {
1991 DwarfCompileUnit *TheCU = I.second;
1993 // Iterate over the misc ranges for the compile units in the module.
1994 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1995 // Emit our symbol so we can find the beginning of the range.
1996 Asm->OutStreamer.EmitLabel(List.getSym());
1998 for (const RangeSpan &Range : List.getRanges()) {
1999 const MCSymbol *Begin = Range.getStart();
2000 const MCSymbol *End = Range.getEnd();
2001 assert(Begin && "Range without a begin symbol?");
2002 assert(End && "Range without an end symbol?");
2003 if (TheCU->getRanges().size() == 1) {
2004 // Grab the begin symbol from the first range as our base.
2005 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2006 Asm->EmitLabelDifference(Begin, Base, Size);
2007 Asm->EmitLabelDifference(End, Base, Size);
2009 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2010 Asm->OutStreamer.EmitSymbolValue(End, Size);
2014 // And terminate the list with two 0 values.
2015 Asm->OutStreamer.EmitIntValue(0, Size);
2016 Asm->OutStreamer.EmitIntValue(0, Size);
2019 // Now emit a range for the CU itself.
2020 if (TheCU->getRanges().size() > 1) {
2021 Asm->OutStreamer.EmitLabel(
2022 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2023 for (const RangeSpan &Range : TheCU->getRanges()) {
2024 const MCSymbol *Begin = Range.getStart();
2025 const MCSymbol *End = Range.getEnd();
2026 assert(Begin && "Range without a begin symbol?");
2027 assert(End && "Range without an end symbol?");
2028 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2029 Asm->OutStreamer.EmitSymbolValue(End, Size);
2031 // And terminate the list with two 0 values.
2032 Asm->OutStreamer.EmitIntValue(0, Size);
2033 Asm->OutStreamer.EmitIntValue(0, Size);
2038 // DWARF5 Experimental Separate Dwarf emitters.
2040 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2041 std::unique_ptr<DwarfUnit> NewU) {
2042 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2043 U.getCUNode().getSplitDebugFilename());
2045 if (!CompilationDir.empty())
2046 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2048 addGnuPubAttributes(*NewU, Die);
2050 SkeletonHolder.addUnit(std::move(NewU));
2053 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2054 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2055 // DW_AT_addr_base, DW_AT_ranges_base.
2056 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2058 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2059 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2060 DwarfCompileUnit &NewCU = *OwnedUnit;
2061 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2062 DwarfInfoSectionSym);
2064 NewCU.initStmtList(DwarfLineSectionSym);
2066 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2071 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2072 // compile units that would normally be in debug_info.
2073 void DwarfDebug::emitDebugInfoDWO() {
2074 assert(useSplitDwarf() && "No split dwarf debug info?");
2075 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2076 // emit relocations into the dwo file.
2077 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2080 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2081 // abbreviations for the .debug_info.dwo section.
2082 void DwarfDebug::emitDebugAbbrevDWO() {
2083 assert(useSplitDwarf() && "No split dwarf?");
2084 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2087 void DwarfDebug::emitDebugLineDWO() {
2088 assert(useSplitDwarf() && "No split dwarf?");
2089 Asm->OutStreamer.SwitchSection(
2090 Asm->getObjFileLowering().getDwarfLineDWOSection());
2091 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2094 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2095 // string section and is identical in format to traditional .debug_str
2097 void DwarfDebug::emitDebugStrDWO() {
2098 assert(useSplitDwarf() && "No split dwarf?");
2099 const MCSection *OffSec =
2100 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2101 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2105 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2106 if (!useSplitDwarf())
2109 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2110 return &SplitTypeUnitFileTable;
2113 static uint64_t makeTypeSignature(StringRef Identifier) {
2115 Hash.update(Identifier);
2116 // ... take the least significant 8 bytes and return those. Our MD5
2117 // implementation always returns its results in little endian, swap bytes
2119 MD5::MD5Result Result;
2121 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2124 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2125 StringRef Identifier, DIE &RefDie,
2126 DICompositeType CTy) {
2127 // Fast path if we're building some type units and one has already used the
2128 // address pool we know we're going to throw away all this work anyway, so
2129 // don't bother building dependent types.
2130 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2133 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2135 CU.addDIETypeSignature(RefDie, *TU);
2139 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2140 AddrPool.resetUsedFlag();
2142 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2143 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2144 this, &InfoHolder, getDwoLineTable(CU));
2145 DwarfTypeUnit &NewTU = *OwnedUnit;
2146 DIE &UnitDie = NewTU.getUnitDie();
2148 TypeUnitsUnderConstruction.push_back(
2149 std::make_pair(std::move(OwnedUnit), CTy));
2151 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2154 uint64_t Signature = makeTypeSignature(Identifier);
2155 NewTU.setTypeSignature(Signature);
2157 if (useSplitDwarf())
2158 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2159 DwarfTypesDWOSectionSym);
2161 CU.applyStmtList(UnitDie);
2163 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2166 NewTU.setType(NewTU.createTypeDIE(CTy));
2169 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2170 TypeUnitsUnderConstruction.clear();
2172 // Types referencing entries in the address table cannot be placed in type
2174 if (AddrPool.hasBeenUsed()) {
2176 // Remove all the types built while building this type.
2177 // This is pessimistic as some of these types might not be dependent on
2178 // the type that used an address.
2179 for (const auto &TU : TypeUnitsToAdd)
2180 DwarfTypeUnits.erase(TU.second);
2182 // Construct this type in the CU directly.
2183 // This is inefficient because all the dependent types will be rebuilt
2184 // from scratch, including building them in type units, discovering that
2185 // they depend on addresses, throwing them out and rebuilding them.
2186 CU.constructTypeDIE(RefDie, CTy);
2190 // If the type wasn't dependent on fission addresses, finish adding the type
2191 // and all its dependent types.
2192 for (auto &TU : TypeUnitsToAdd)
2193 InfoHolder.addUnit(std::move(TU.first));
2195 CU.addDIETypeSignature(RefDie, NewTU);
2198 // Accelerator table mutators - add each name along with its companion
2199 // DIE to the proper table while ensuring that the name that we're going
2200 // to reference is in the string table. We do this since the names we
2201 // add may not only be identical to the names in the DIE.
2202 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2203 if (!useDwarfAccelTables())
2205 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2209 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2210 if (!useDwarfAccelTables())
2212 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2216 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2217 if (!useDwarfAccelTables())
2219 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2223 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2224 if (!useDwarfAccelTables())
2226 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),