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",
1566 &DwarfCompileUnit::getGlobalNames);
1569 void DwarfDebug::emitDebugPubSection(
1570 bool GnuStyle, const MCSection *PSec, StringRef Name,
1571 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1572 for (const auto &NU : CUMap) {
1573 DwarfCompileUnit *TheU = NU.second;
1575 const auto &Globals = (TheU->*Accessor)();
1577 if (Globals.empty())
1580 if (auto *Skeleton = TheU->getSkeleton())
1582 unsigned ID = TheU->getUniqueID();
1584 // Start the dwarf pubnames section.
1585 Asm->OutStreamer.SwitchSection(PSec);
1588 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1589 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1590 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1591 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1593 Asm->OutStreamer.EmitLabel(BeginLabel);
1595 Asm->OutStreamer.AddComment("DWARF Version");
1596 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1598 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1599 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1601 Asm->OutStreamer.AddComment("Compilation Unit Length");
1602 Asm->EmitInt32(TheU->getLength());
1604 // Emit the pubnames for this compilation unit.
1605 for (const auto &GI : Globals) {
1606 const char *Name = GI.getKeyData();
1607 const DIE *Entity = GI.second;
1609 Asm->OutStreamer.AddComment("DIE offset");
1610 Asm->EmitInt32(Entity->getOffset());
1613 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1614 Asm->OutStreamer.AddComment(
1615 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1616 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1617 Asm->EmitInt8(Desc.toBits());
1620 Asm->OutStreamer.AddComment("External Name");
1621 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1624 Asm->OutStreamer.AddComment("End Mark");
1626 Asm->OutStreamer.EmitLabel(EndLabel);
1630 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1631 const MCSection *PSec =
1632 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1633 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1635 emitDebugPubSection(GnuStyle, PSec, "Types",
1636 &DwarfCompileUnit::getGlobalTypes);
1639 // Emit visible names into a debug str section.
1640 void DwarfDebug::emitDebugStr() {
1641 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1642 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1645 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1646 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1647 const DITypeIdentifierMap &Map,
1648 ArrayRef<DebugLocEntry::Value> Values) {
1649 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1650 return P.isVariablePiece();
1651 }) && "all values are expected to be pieces");
1652 assert(std::is_sorted(Values.begin(), Values.end()) &&
1653 "pieces are expected to be sorted");
1655 unsigned Offset = 0;
1656 for (auto Piece : Values) {
1657 DIExpression Expr = Piece.getExpression();
1658 unsigned PieceOffset = Expr.getPieceOffset();
1659 unsigned PieceSize = Expr.getPieceSize();
1660 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1661 if (Offset < PieceOffset) {
1662 // The DWARF spec seriously mandates pieces with no locations for gaps.
1663 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1664 Offset += PieceOffset-Offset;
1667 Offset += PieceSize;
1669 const unsigned SizeOfByte = 8;
1671 DIVariable Var = Piece.getVariable();
1672 assert(!Var.isIndirect() && "indirect address for piece");
1673 unsigned VarSize = Var.getSizeInBits(Map);
1674 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1675 && "piece is larger than or outside of variable");
1676 assert(PieceSize*SizeOfByte != VarSize
1677 && "piece covers entire variable");
1679 if (Piece.isLocation() && Piece.getLoc().isReg())
1680 Asm->EmitDwarfRegOpPiece(Streamer,
1682 PieceSize*SizeOfByte);
1684 emitDebugLocValue(Streamer, Piece);
1685 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1691 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1692 const DebugLocEntry &Entry) {
1693 const DebugLocEntry::Value Value = Entry.getValues()[0];
1694 if (Value.isVariablePiece())
1695 // Emit all pieces that belong to the same variable and range.
1696 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1698 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1699 emitDebugLocValue(Streamer, Value);
1702 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1703 const DebugLocEntry::Value &Value) {
1704 DIVariable DV = Value.getVariable();
1706 if (Value.isInt()) {
1707 DIBasicType BTy(resolve(DV.getType()));
1708 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1709 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1710 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1711 Streamer.EmitSLEB128(Value.getInt());
1713 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1714 Streamer.EmitULEB128(Value.getInt());
1716 } else if (Value.isLocation()) {
1717 MachineLocation Loc = Value.getLoc();
1718 DIExpression Expr = Value.getExpression();
1721 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1723 // Complex address entry.
1724 unsigned N = Expr.getNumElements();
1726 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1727 if (Loc.getOffset()) {
1729 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1730 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1731 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1732 Streamer.EmitSLEB128(Expr.getElement(1));
1734 // If first address element is OpPlus then emit
1735 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1736 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1737 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1741 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1744 // Emit remaining complex address elements.
1745 for (; i < N; ++i) {
1746 uint64_t Element = Expr.getElement(i);
1747 if (Element == dwarf::DW_OP_plus) {
1748 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1749 Streamer.EmitULEB128(Expr.getElement(++i));
1750 } else if (Element == dwarf::DW_OP_deref) {
1752 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1753 } else if (Element == dwarf::DW_OP_piece) {
1755 // handled in emitDebugLocEntry.
1757 llvm_unreachable("unknown Opcode found in complex address");
1761 // else ... ignore constant fp. There is not any good way to
1762 // to represent them here in dwarf.
1766 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1767 Asm->OutStreamer.AddComment("Loc expr size");
1768 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1769 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1770 Asm->EmitLabelDifference(end, begin, 2);
1771 Asm->OutStreamer.EmitLabel(begin);
1773 APByteStreamer Streamer(*Asm);
1774 emitDebugLocEntry(Streamer, Entry);
1776 Asm->OutStreamer.EmitLabel(end);
1779 // Emit locations into the debug loc section.
1780 void DwarfDebug::emitDebugLoc() {
1781 // Start the dwarf loc section.
1782 Asm->OutStreamer.SwitchSection(
1783 Asm->getObjFileLowering().getDwarfLocSection());
1784 unsigned char Size = Asm->getDataLayout().getPointerSize();
1785 for (const auto &DebugLoc : DotDebugLocEntries) {
1786 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1787 const DwarfCompileUnit *CU = DebugLoc.CU;
1788 assert(!CU->getRanges().empty());
1789 for (const auto &Entry : DebugLoc.List) {
1790 // Set up the range. This range is relative to the entry point of the
1791 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1792 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1793 if (CU->getRanges().size() == 1) {
1794 // Grab the begin symbol from the first range as our base.
1795 const MCSymbol *Base = CU->getRanges()[0].getStart();
1796 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1797 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1799 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1800 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1803 emitDebugLocEntryLocation(Entry);
1805 Asm->OutStreamer.EmitIntValue(0, Size);
1806 Asm->OutStreamer.EmitIntValue(0, Size);
1810 void DwarfDebug::emitDebugLocDWO() {
1811 Asm->OutStreamer.SwitchSection(
1812 Asm->getObjFileLowering().getDwarfLocDWOSection());
1813 for (const auto &DebugLoc : DotDebugLocEntries) {
1814 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1815 for (const auto &Entry : DebugLoc.List) {
1816 // Just always use start_length for now - at least that's one address
1817 // rather than two. We could get fancier and try to, say, reuse an
1818 // address we know we've emitted elsewhere (the start of the function?
1819 // The start of the CU or CU subrange that encloses this range?)
1820 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1821 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1822 Asm->EmitULEB128(idx);
1823 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1825 emitDebugLocEntryLocation(Entry);
1827 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1832 const MCSymbol *Start, *End;
1835 // Emit a debug aranges section, containing a CU lookup for any
1836 // address we can tie back to a CU.
1837 void DwarfDebug::emitDebugARanges() {
1838 // Start the dwarf aranges section.
1839 Asm->OutStreamer.SwitchSection(
1840 Asm->getObjFileLowering().getDwarfARangesSection());
1842 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1846 // Build a list of sections used.
1847 std::vector<const MCSection *> Sections;
1848 for (const auto &it : SectionMap) {
1849 const MCSection *Section = it.first;
1850 Sections.push_back(Section);
1853 // Sort the sections into order.
1854 // This is only done to ensure consistent output order across different runs.
1855 std::sort(Sections.begin(), Sections.end(), SectionSort);
1857 // Build a set of address spans, sorted by CU.
1858 for (const MCSection *Section : Sections) {
1859 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1860 if (List.size() < 2)
1863 // Sort the symbols by offset within the section.
1864 std::sort(List.begin(), List.end(),
1865 [&](const SymbolCU &A, const SymbolCU &B) {
1866 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1867 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1869 // Symbols with no order assigned should be placed at the end.
1870 // (e.g. section end labels)
1878 // If we have no section (e.g. common), just write out
1879 // individual spans for each symbol.
1881 for (const SymbolCU &Cur : List) {
1883 Span.Start = Cur.Sym;
1886 Spans[Cur.CU].push_back(Span);
1889 // Build spans between each label.
1890 const MCSymbol *StartSym = List[0].Sym;
1891 for (size_t n = 1, e = List.size(); n < e; n++) {
1892 const SymbolCU &Prev = List[n - 1];
1893 const SymbolCU &Cur = List[n];
1895 // Try and build the longest span we can within the same CU.
1896 if (Cur.CU != Prev.CU) {
1898 Span.Start = StartSym;
1900 Spans[Prev.CU].push_back(Span);
1907 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1909 // Build a list of CUs used.
1910 std::vector<DwarfCompileUnit *> CUs;
1911 for (const auto &it : Spans) {
1912 DwarfCompileUnit *CU = it.first;
1916 // Sort the CU list (again, to ensure consistent output order).
1917 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1918 return A->getUniqueID() < B->getUniqueID();
1921 // Emit an arange table for each CU we used.
1922 for (DwarfCompileUnit *CU : CUs) {
1923 std::vector<ArangeSpan> &List = Spans[CU];
1925 // Describe the skeleton CU's offset and length, not the dwo file's.
1926 if (auto *Skel = CU->getSkeleton())
1929 // Emit size of content not including length itself.
1930 unsigned ContentSize =
1931 sizeof(int16_t) + // DWARF ARange version number
1932 sizeof(int32_t) + // Offset of CU in the .debug_info section
1933 sizeof(int8_t) + // Pointer Size (in bytes)
1934 sizeof(int8_t); // Segment Size (in bytes)
1936 unsigned TupleSize = PtrSize * 2;
1938 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1940 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1942 ContentSize += Padding;
1943 ContentSize += (List.size() + 1) * TupleSize;
1945 // For each compile unit, write the list of spans it covers.
1946 Asm->OutStreamer.AddComment("Length of ARange Set");
1947 Asm->EmitInt32(ContentSize);
1948 Asm->OutStreamer.AddComment("DWARF Arange version number");
1949 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1950 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1951 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1952 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1953 Asm->EmitInt8(PtrSize);
1954 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1957 Asm->OutStreamer.EmitFill(Padding, 0xff);
1959 for (const ArangeSpan &Span : List) {
1960 Asm->EmitLabelReference(Span.Start, PtrSize);
1962 // Calculate the size as being from the span start to it's end.
1964 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1966 // For symbols without an end marker (e.g. common), we
1967 // write a single arange entry containing just that one symbol.
1968 uint64_t Size = SymSize[Span.Start];
1972 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1976 Asm->OutStreamer.AddComment("ARange terminator");
1977 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1978 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1982 // Emit visible names into a debug ranges section.
1983 void DwarfDebug::emitDebugRanges() {
1984 // Start the dwarf ranges section.
1985 Asm->OutStreamer.SwitchSection(
1986 Asm->getObjFileLowering().getDwarfRangesSection());
1988 // Size for our labels.
1989 unsigned char Size = Asm->getDataLayout().getPointerSize();
1991 // Grab the specific ranges for the compile units in the module.
1992 for (const auto &I : CUMap) {
1993 DwarfCompileUnit *TheCU = I.second;
1995 // Iterate over the misc ranges for the compile units in the module.
1996 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1997 // Emit our symbol so we can find the beginning of the range.
1998 Asm->OutStreamer.EmitLabel(List.getSym());
2000 for (const RangeSpan &Range : List.getRanges()) {
2001 const MCSymbol *Begin = Range.getStart();
2002 const MCSymbol *End = Range.getEnd();
2003 assert(Begin && "Range without a begin symbol?");
2004 assert(End && "Range without an end symbol?");
2005 if (TheCU->getRanges().size() == 1) {
2006 // Grab the begin symbol from the first range as our base.
2007 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2008 Asm->EmitLabelDifference(Begin, Base, Size);
2009 Asm->EmitLabelDifference(End, Base, Size);
2011 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2012 Asm->OutStreamer.EmitSymbolValue(End, Size);
2016 // And terminate the list with two 0 values.
2017 Asm->OutStreamer.EmitIntValue(0, Size);
2018 Asm->OutStreamer.EmitIntValue(0, Size);
2021 // Now emit a range for the CU itself.
2022 if (TheCU->getRanges().size() > 1) {
2023 Asm->OutStreamer.EmitLabel(
2024 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2025 for (const RangeSpan &Range : TheCU->getRanges()) {
2026 const MCSymbol *Begin = Range.getStart();
2027 const MCSymbol *End = Range.getEnd();
2028 assert(Begin && "Range without a begin symbol?");
2029 assert(End && "Range without an end symbol?");
2030 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2031 Asm->OutStreamer.EmitSymbolValue(End, Size);
2033 // And terminate the list with two 0 values.
2034 Asm->OutStreamer.EmitIntValue(0, Size);
2035 Asm->OutStreamer.EmitIntValue(0, Size);
2040 // DWARF5 Experimental Separate Dwarf emitters.
2042 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2043 std::unique_ptr<DwarfUnit> NewU) {
2044 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2045 U.getCUNode().getSplitDebugFilename());
2047 if (!CompilationDir.empty())
2048 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2050 addGnuPubAttributes(*NewU, Die);
2052 SkeletonHolder.addUnit(std::move(NewU));
2055 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2056 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2057 // DW_AT_addr_base, DW_AT_ranges_base.
2058 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2060 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2061 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2062 DwarfCompileUnit &NewCU = *OwnedUnit;
2063 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2064 DwarfInfoSectionSym);
2066 NewCU.initStmtList(DwarfLineSectionSym);
2068 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2073 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2074 // compile units that would normally be in debug_info.
2075 void DwarfDebug::emitDebugInfoDWO() {
2076 assert(useSplitDwarf() && "No split dwarf debug info?");
2077 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2078 // emit relocations into the dwo file.
2079 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2082 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2083 // abbreviations for the .debug_info.dwo section.
2084 void DwarfDebug::emitDebugAbbrevDWO() {
2085 assert(useSplitDwarf() && "No split dwarf?");
2086 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2089 void DwarfDebug::emitDebugLineDWO() {
2090 assert(useSplitDwarf() && "No split dwarf?");
2091 Asm->OutStreamer.SwitchSection(
2092 Asm->getObjFileLowering().getDwarfLineDWOSection());
2093 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2096 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2097 // string section and is identical in format to traditional .debug_str
2099 void DwarfDebug::emitDebugStrDWO() {
2100 assert(useSplitDwarf() && "No split dwarf?");
2101 const MCSection *OffSec =
2102 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2103 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2107 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2108 if (!useSplitDwarf())
2111 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2112 return &SplitTypeUnitFileTable;
2115 static uint64_t makeTypeSignature(StringRef Identifier) {
2117 Hash.update(Identifier);
2118 // ... take the least significant 8 bytes and return those. Our MD5
2119 // implementation always returns its results in little endian, swap bytes
2121 MD5::MD5Result Result;
2123 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2126 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2127 StringRef Identifier, DIE &RefDie,
2128 DICompositeType CTy) {
2129 // Fast path if we're building some type units and one has already used the
2130 // address pool we know we're going to throw away all this work anyway, so
2131 // don't bother building dependent types.
2132 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2135 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2137 CU.addDIETypeSignature(RefDie, *TU);
2141 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2142 AddrPool.resetUsedFlag();
2144 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2145 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2146 this, &InfoHolder, getDwoLineTable(CU));
2147 DwarfTypeUnit &NewTU = *OwnedUnit;
2148 DIE &UnitDie = NewTU.getUnitDie();
2150 TypeUnitsUnderConstruction.push_back(
2151 std::make_pair(std::move(OwnedUnit), CTy));
2153 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2156 uint64_t Signature = makeTypeSignature(Identifier);
2157 NewTU.setTypeSignature(Signature);
2159 if (useSplitDwarf())
2160 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2162 CU.applyStmtList(UnitDie);
2164 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2167 NewTU.setType(NewTU.createTypeDIE(CTy));
2170 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2171 TypeUnitsUnderConstruction.clear();
2173 // Types referencing entries in the address table cannot be placed in type
2175 if (AddrPool.hasBeenUsed()) {
2177 // Remove all the types built while building this type.
2178 // This is pessimistic as some of these types might not be dependent on
2179 // the type that used an address.
2180 for (const auto &TU : TypeUnitsToAdd)
2181 DwarfTypeUnits.erase(TU.second);
2183 // Construct this type in the CU directly.
2184 // This is inefficient because all the dependent types will be rebuilt
2185 // from scratch, including building them in type units, discovering that
2186 // they depend on addresses, throwing them out and rebuilding them.
2187 CU.constructTypeDIE(RefDie, CTy);
2191 // If the type wasn't dependent on fission addresses, finish adding the type
2192 // and all its dependent types.
2193 for (auto &TU : TypeUnitsToAdd)
2194 InfoHolder.addUnit(std::move(TU.first));
2196 CU.addDIETypeSignature(RefDie, NewTU);
2199 // Accelerator table mutators - add each name along with its companion
2200 // DIE to the proper table while ensuring that the name that we're going
2201 // to reference is in the string table. We do this since the names we
2202 // add may not only be identical to the names in the DIE.
2203 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2204 if (!useDwarfAccelTables())
2206 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2210 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2211 if (!useDwarfAccelTables())
2213 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2217 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2218 if (!useDwarfAccelTables())
2220 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2224 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2225 if (!useDwarfAccelTables())
2227 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),