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 NewCU.setSkeleton(constructSkeletonCU(NewCU));
368 // LTO with assembly output shares a single line table amongst multiple CUs.
369 // To avoid the compilation directory being ambiguous, let the line table
370 // explicitly describe the directory of all files, never relying on the
371 // compilation directory.
372 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
373 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
374 NewCU.getUniqueID(), CompilationDir);
376 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
377 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
378 DIUnit.getLanguage());
379 NewCU.addString(Die, dwarf::DW_AT_name, FN);
381 if (!useSplitDwarf()) {
382 NewCU.initStmtList(DwarfLineSectionSym);
384 // If we're using split dwarf the compilation dir is going to be in the
385 // skeleton CU and so we don't need to duplicate it here.
386 if (!CompilationDir.empty())
387 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
389 addGnuPubAttributes(NewCU, Die);
392 if (DIUnit.isOptimized())
393 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
395 StringRef Flags = DIUnit.getFlags();
397 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
399 if (unsigned RVer = DIUnit.getRunTimeVersion())
400 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
401 dwarf::DW_FORM_data1, RVer);
404 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
405 DwarfInfoDWOSectionSym);
407 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
408 DwarfInfoSectionSym);
410 CUMap.insert(std::make_pair(DIUnit, &NewCU));
411 CUDieMap.insert(std::make_pair(&Die, &NewCU));
415 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
417 DIImportedEntity Module(N);
418 assert(Module.Verify());
419 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
420 D->addChild(TheCU.constructImportedEntityDIE(Module));
423 // Emit all Dwarf sections that should come prior to the content. Create
424 // global DIEs and emit initial debug info sections. This is invoked by
425 // the target AsmPrinter.
426 void DwarfDebug::beginModule() {
427 if (DisableDebugInfoPrinting)
430 const Module *M = MMI->getModule();
432 FunctionDIs = makeSubprogramMap(*M);
434 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
437 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
439 // Emit initial sections so we can reference labels later.
442 SingleCU = CU_Nodes->getNumOperands() == 1;
444 for (MDNode *N : CU_Nodes->operands()) {
445 DICompileUnit CUNode(N);
446 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
447 DIArray ImportedEntities = CUNode.getImportedEntities();
448 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
449 ScopesWithImportedEntities.push_back(std::make_pair(
450 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
451 ImportedEntities.getElement(i)));
452 std::sort(ScopesWithImportedEntities.begin(),
453 ScopesWithImportedEntities.end(), less_first());
454 DIArray GVs = CUNode.getGlobalVariables();
455 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
456 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
457 DIArray SPs = CUNode.getSubprograms();
458 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
459 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
460 DIArray EnumTypes = CUNode.getEnumTypes();
461 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
462 DIType Ty(EnumTypes.getElement(i));
463 // The enum types array by design contains pointers to
464 // MDNodes rather than DIRefs. Unique them here.
465 DIType UniqueTy(resolve(Ty.getRef()));
466 CU.getOrCreateTypeDIE(UniqueTy);
468 DIArray RetainedTypes = CUNode.getRetainedTypes();
469 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
470 DIType Ty(RetainedTypes.getElement(i));
471 // The retained types array by design contains pointers to
472 // MDNodes rather than DIRefs. Unique them here.
473 DIType UniqueTy(resolve(Ty.getRef()));
474 CU.getOrCreateTypeDIE(UniqueTy);
476 // Emit imported_modules last so that the relevant context is already
478 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
479 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
482 // Tell MMI that we have debug info.
483 MMI->setDebugInfoAvailability(true);
485 // Prime section data.
486 SectionMap[Asm->getObjFileLowering().getTextSection()];
489 void DwarfDebug::finishVariableDefinitions() {
490 for (const auto &Var : ConcreteVariables) {
491 DIE *VariableDie = Var->getDIE();
493 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
494 // in the ConcreteVariables list, rather than looking it up again here.
495 // DIE::getUnit isn't simple - it walks parent pointers, etc.
496 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
498 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
499 if (AbsVar && AbsVar->getDIE()) {
500 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
503 Unit->applyVariableAttributes(*Var, *VariableDie);
507 void DwarfDebug::finishSubprogramDefinitions() {
508 for (const auto &P : SPMap)
509 P.second->finishSubprogramDefinition(DISubprogram(P.first));
513 // Collect info for variables that were optimized out.
514 void DwarfDebug::collectDeadVariables() {
515 const Module *M = MMI->getModule();
517 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
518 for (MDNode *N : CU_Nodes->operands()) {
519 DICompileUnit TheCU(N);
520 // Construct subprogram DIE and add variables DIEs.
521 DwarfCompileUnit *SPCU =
522 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
523 assert(SPCU && "Unable to find Compile Unit!");
524 DIArray Subprograms = TheCU.getSubprograms();
525 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
526 DISubprogram SP(Subprograms.getElement(i));
527 if (ProcessedSPNodes.count(SP) != 0)
529 SPCU->collectDeadVariables(SP);
535 void DwarfDebug::finalizeModuleInfo() {
536 finishSubprogramDefinitions();
538 finishVariableDefinitions();
540 // Collect info for variables that were optimized out.
541 collectDeadVariables();
543 // Handle anything that needs to be done on a per-unit basis after
544 // all other generation.
545 for (const auto &P : CUMap) {
546 auto &TheCU = *P.second;
547 // Emit DW_AT_containing_type attribute to connect types with their
548 // vtable holding type.
549 TheCU.constructContainingTypeDIEs();
551 // Add CU specific attributes if we need to add any.
552 // If we're splitting the dwarf out now that we've got the entire
553 // CU then add the dwo id to it.
554 auto *SkCU = TheCU.getSkeleton();
555 if (useSplitDwarf()) {
556 // Emit a unique identifier for this CU.
557 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
558 TheCU.addUInt(TheCU.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 (!SkCU->getRangeLists().empty())
569 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
570 DwarfDebugRangeSectionSym,
571 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 = SkCU ? *SkCU : TheCU;
581 if (unsigned NumRanges = TheCU.getRanges().size()) {
583 // A DW_AT_low_pc attribute may also be specified in combination with
584 // DW_AT_ranges to specify the default base address for use in
585 // location lists (see Section 2.6.2) and range lists (see Section
587 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
589 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
590 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
594 // Compute DIE offsets and sizes.
595 InfoHolder.computeSizeAndOffsets();
597 SkeletonHolder.computeSizeAndOffsets();
600 void DwarfDebug::endSections() {
601 // Filter labels by section.
602 for (const SymbolCU &SCU : ArangeLabels) {
603 if (SCU.Sym->isInSection()) {
604 // Make a note of this symbol and it's section.
605 const MCSection *Section = &SCU.Sym->getSection();
606 if (!Section->getKind().isMetadata())
607 SectionMap[Section].push_back(SCU);
609 // Some symbols (e.g. common/bss on mach-o) can have no section but still
610 // appear in the output. This sucks as we rely on sections to build
611 // arange spans. We can do it without, but it's icky.
612 SectionMap[nullptr].push_back(SCU);
616 // Build a list of sections used.
617 std::vector<const MCSection *> Sections;
618 for (const auto &it : SectionMap) {
619 const MCSection *Section = it.first;
620 Sections.push_back(Section);
623 // Sort the sections into order.
624 // This is only done to ensure consistent output order across different runs.
625 std::sort(Sections.begin(), Sections.end(), SectionSort);
627 // Add terminating symbols for each section.
628 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
629 const MCSection *Section = Sections[ID];
630 MCSymbol *Sym = nullptr;
633 // We can't call MCSection::getLabelEndName, as it's only safe to do so
634 // if we know the section name up-front. For user-created sections, the
635 // resulting label may not be valid to use as a label. (section names can
636 // use a greater set of characters on some systems)
637 Sym = Asm->GetTempSymbol("debug_end", ID);
638 Asm->OutStreamer.SwitchSection(Section);
639 Asm->OutStreamer.EmitLabel(Sym);
642 // Insert a final terminator.
643 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
647 // Emit all Dwarf sections that should come after the content.
648 void DwarfDebug::endModule() {
649 assert(CurFn == nullptr);
650 assert(CurMI == nullptr);
652 // If we aren't actually generating debug info (check beginModule -
653 // conditionalized on !DisableDebugInfoPrinting and the presence of the
654 // llvm.dbg.cu metadata node)
655 if (!DwarfInfoSectionSym)
658 // End any existing sections.
659 // TODO: Does this need to happen?
662 // Finalize the debug info for the module.
663 finalizeModuleInfo();
667 // Emit all the DIEs into a debug info section.
670 // Corresponding abbreviations into a abbrev section.
673 // Emit info into a debug aranges section.
674 if (GenerateARangeSection)
677 // Emit info into a debug ranges section.
680 if (useSplitDwarf()) {
683 emitDebugAbbrevDWO();
686 // Emit DWO addresses.
687 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
689 // Emit info into a debug loc section.
692 // Emit info into the dwarf accelerator table sections.
693 if (useDwarfAccelTables()) {
696 emitAccelNamespaces();
700 // Emit the pubnames and pubtypes sections if requested.
701 if (HasDwarfPubSections) {
702 emitDebugPubNames(GenerateGnuPubSections);
703 emitDebugPubTypes(GenerateGnuPubSections);
708 AbstractVariables.clear();
711 // Find abstract variable, if any, associated with Var.
712 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
713 DIVariable &Cleansed) {
714 LLVMContext &Ctx = DV->getContext();
715 // More then one inlined variable corresponds to one abstract variable.
716 // FIXME: This duplication of variables when inlining should probably be
717 // removed. It's done to allow each DIVariable to describe its location
718 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
719 // make it accurate then remove this duplication/cleansing stuff.
720 Cleansed = cleanseInlinedVariable(DV, Ctx);
721 auto I = AbstractVariables.find(Cleansed);
722 if (I != AbstractVariables.end())
723 return I->second.get();
727 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
729 return getExistingAbstractVariable(DV, Cleansed);
732 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
733 LexicalScope *Scope) {
734 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
735 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
736 AbstractVariables[Var] = std::move(AbsDbgVariable);
739 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
740 const MDNode *ScopeNode) {
741 DIVariable Cleansed = DV;
742 if (getExistingAbstractVariable(DV, Cleansed))
745 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
749 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
750 const MDNode *ScopeNode) {
751 DIVariable Cleansed = DV;
752 if (getExistingAbstractVariable(DV, Cleansed))
755 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
756 createAbstractVariable(Cleansed, Scope);
759 // Collect variable information from side table maintained by MMI.
760 void DwarfDebug::collectVariableInfoFromMMITable(
761 SmallPtrSetImpl<const MDNode *> &Processed) {
762 for (const auto &VI : MMI->getVariableDbgInfo()) {
765 Processed.insert(VI.Var);
766 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
768 // If variable scope is not found then skip this variable.
772 DIVariable DV(VI.Var);
773 DIExpression Expr(VI.Expr);
774 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
775 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
776 DbgVariable *RegVar = ConcreteVariables.back().get();
777 RegVar->setFrameIndex(VI.Slot);
778 InfoHolder.addScopeVariable(Scope, RegVar);
782 // Get .debug_loc entry for the instruction range starting at MI.
783 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
784 const MDNode *Expr = MI->getDebugExpression();
785 const MDNode *Var = MI->getDebugVariable();
787 assert(MI->getNumOperands() == 4);
788 if (MI->getOperand(0).isReg()) {
789 MachineLocation MLoc;
790 // If the second operand is an immediate, this is a
791 // register-indirect address.
792 if (!MI->getOperand(1).isImm())
793 MLoc.set(MI->getOperand(0).getReg());
795 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
796 return DebugLocEntry::Value(Var, Expr, MLoc);
798 if (MI->getOperand(0).isImm())
799 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
800 if (MI->getOperand(0).isFPImm())
801 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
802 if (MI->getOperand(0).isCImm())
803 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
805 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
808 /// Determine whether two variable pieces overlap.
809 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
810 if (!P1.isVariablePiece() || !P2.isVariablePiece())
812 unsigned l1 = P1.getPieceOffset();
813 unsigned l2 = P2.getPieceOffset();
814 unsigned r1 = l1 + P1.getPieceSize();
815 unsigned r2 = l2 + P2.getPieceSize();
816 // True where [l1,r1[ and [r1,r2[ overlap.
817 return (l1 < r2) && (l2 < r1);
820 /// Build the location list for all DBG_VALUEs in the function that
821 /// describe the same variable. If the ranges of several independent
822 /// pieces of the same variable overlap partially, split them up and
823 /// combine the ranges. The resulting DebugLocEntries are will have
824 /// strict monotonically increasing begin addresses and will never
829 // Ranges History [var, loc, piece ofs size]
830 // 0 | [x, (reg0, piece 0, 32)]
831 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
833 // 3 | [clobber reg0]
834 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
838 // [0-1] [x, (reg0, piece 0, 32)]
839 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
840 // [3-4] [x, (reg1, piece 32, 32)]
841 // [4- ] [x, (mem, piece 0, 64)]
843 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
844 const DbgValueHistoryMap::InstrRanges &Ranges) {
845 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
847 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
848 const MachineInstr *Begin = I->first;
849 const MachineInstr *End = I->second;
850 assert(Begin->isDebugValue() && "Invalid History entry");
852 // Check if a variable is inaccessible in this range.
853 if (Begin->getNumOperands() > 1 &&
854 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
859 // If this piece overlaps with any open ranges, truncate them.
860 DIExpression DIExpr = Begin->getDebugExpression();
861 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
862 [&](DebugLocEntry::Value R) {
863 return piecesOverlap(DIExpr, R.getExpression());
865 OpenRanges.erase(Last, OpenRanges.end());
867 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
868 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
870 const MCSymbol *EndLabel;
872 EndLabel = getLabelAfterInsn(End);
873 else if (std::next(I) == Ranges.end())
874 EndLabel = FunctionEndSym;
876 EndLabel = getLabelBeforeInsn(std::next(I)->first);
877 assert(EndLabel && "Forgot label after instruction ending a range!");
879 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
881 auto Value = getDebugLocValue(Begin);
882 DebugLocEntry Loc(StartLabel, EndLabel, Value);
883 bool couldMerge = false;
885 // If this is a piece, it may belong to the current DebugLocEntry.
886 if (DIExpr.isVariablePiece()) {
887 // Add this value to the list of open ranges.
888 OpenRanges.push_back(Value);
890 // Attempt to add the piece to the last entry.
891 if (!DebugLoc.empty())
892 if (DebugLoc.back().MergeValues(Loc))
897 // Need to add a new DebugLocEntry. Add all values from still
898 // valid non-overlapping pieces.
899 if (OpenRanges.size())
900 Loc.addValues(OpenRanges);
902 DebugLoc.push_back(std::move(Loc));
905 // Attempt to coalesce the ranges of two otherwise identical
907 auto CurEntry = DebugLoc.rbegin();
908 auto PrevEntry = std::next(CurEntry);
909 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
913 dbgs() << CurEntry->getValues().size() << " Values:\n";
914 for (auto Value : CurEntry->getValues()) {
915 Value.getVariable()->dump();
916 Value.getExpression()->dump();
924 // Find variables for each lexical scope.
926 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
927 SmallPtrSetImpl<const MDNode *> &Processed) {
928 // Grab the variable info that was squirreled away in the MMI side-table.
929 collectVariableInfoFromMMITable(Processed);
931 for (const auto &I : DbgValues) {
932 DIVariable DV(I.first);
933 if (Processed.count(DV))
936 // Instruction ranges, specifying where DV is accessible.
937 const auto &Ranges = I.second;
941 LexicalScope *Scope = nullptr;
942 if (MDNode *IA = DV.getInlinedAt()) {
943 DebugLoc DL = DebugLoc::getFromDILocation(IA);
944 Scope = LScopes.findInlinedScope(DebugLoc::get(
945 DL.getLine(), DL.getCol(), DV.getContext(), IA));
947 Scope = LScopes.findLexicalScope(DV.getContext());
948 // If variable scope is not found then skip this variable.
952 Processed.insert(DV);
953 const MachineInstr *MInsn = Ranges.front().first;
954 assert(MInsn->isDebugValue() && "History must begin with debug value");
955 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
956 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
957 DbgVariable *RegVar = ConcreteVariables.back().get();
958 InfoHolder.addScopeVariable(Scope, RegVar);
960 // Check if the first DBG_VALUE is valid for the rest of the function.
961 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
964 // Handle multiple DBG_VALUE instructions describing one variable.
965 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
967 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
968 DebugLocList &LocList = DotDebugLocEntries.back();
971 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
973 // Build the location list for this variable.
974 buildLocationList(LocList.List, Ranges);
977 // Collect info for variables that were optimized out.
978 DIArray Variables = SP.getVariables();
979 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
980 DIVariable DV(Variables.getElement(i));
981 assert(DV.isVariable());
982 if (!Processed.insert(DV))
984 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
985 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
987 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
988 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
993 // Return Label preceding the instruction.
994 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
995 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
996 assert(Label && "Didn't insert label before instruction");
1000 // Return Label immediately following the instruction.
1001 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1002 return LabelsAfterInsn.lookup(MI);
1005 // Process beginning of an instruction.
1006 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1007 assert(CurMI == nullptr);
1009 // Check if source location changes, but ignore DBG_VALUE locations.
1010 if (!MI->isDebugValue()) {
1011 DebugLoc DL = MI->getDebugLoc();
1012 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1015 if (DL == PrologEndLoc) {
1016 Flags |= DWARF2_FLAG_PROLOGUE_END;
1017 PrologEndLoc = DebugLoc();
1019 if (PrologEndLoc.isUnknown())
1020 Flags |= DWARF2_FLAG_IS_STMT;
1022 if (!DL.isUnknown()) {
1023 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1024 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1026 recordSourceLine(0, 0, nullptr, 0);
1030 // Insert labels where requested.
1031 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1032 LabelsBeforeInsn.find(MI);
1035 if (I == LabelsBeforeInsn.end())
1038 // Label already assigned.
1043 PrevLabel = MMI->getContext().CreateTempSymbol();
1044 Asm->OutStreamer.EmitLabel(PrevLabel);
1046 I->second = PrevLabel;
1049 // Process end of an instruction.
1050 void DwarfDebug::endInstruction() {
1051 assert(CurMI != nullptr);
1052 // Don't create a new label after DBG_VALUE instructions.
1053 // They don't generate code.
1054 if (!CurMI->isDebugValue())
1055 PrevLabel = nullptr;
1057 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1058 LabelsAfterInsn.find(CurMI);
1062 if (I == LabelsAfterInsn.end())
1065 // Label already assigned.
1069 // We need a label after this instruction.
1071 PrevLabel = MMI->getContext().CreateTempSymbol();
1072 Asm->OutStreamer.EmitLabel(PrevLabel);
1074 I->second = PrevLabel;
1077 // Each LexicalScope has first instruction and last instruction to mark
1078 // beginning and end of a scope respectively. Create an inverse map that list
1079 // scopes starts (and ends) with an instruction. One instruction may start (or
1080 // end) multiple scopes. Ignore scopes that are not reachable.
1081 void DwarfDebug::identifyScopeMarkers() {
1082 SmallVector<LexicalScope *, 4> WorkList;
1083 WorkList.push_back(LScopes.getCurrentFunctionScope());
1084 while (!WorkList.empty()) {
1085 LexicalScope *S = WorkList.pop_back_val();
1087 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1088 if (!Children.empty())
1089 WorkList.append(Children.begin(), Children.end());
1091 if (S->isAbstractScope())
1094 for (const InsnRange &R : S->getRanges()) {
1095 assert(R.first && "InsnRange does not have first instruction!");
1096 assert(R.second && "InsnRange does not have second instruction!");
1097 requestLabelBeforeInsn(R.first);
1098 requestLabelAfterInsn(R.second);
1103 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1104 // First known non-DBG_VALUE and non-frame setup location marks
1105 // the beginning of the function body.
1106 for (const auto &MBB : *MF)
1107 for (const auto &MI : MBB)
1108 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1109 !MI.getDebugLoc().isUnknown())
1110 return MI.getDebugLoc();
1114 // Gather pre-function debug information. Assumes being called immediately
1115 // after the function entry point has been emitted.
1116 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1119 // If there's no debug info for the function we're not going to do anything.
1120 if (!MMI->hasDebugInfo())
1123 auto DI = FunctionDIs.find(MF->getFunction());
1124 if (DI == FunctionDIs.end())
1127 // Grab the lexical scopes for the function, if we don't have any of those
1128 // then we're not going to be able to do anything.
1129 LScopes.initialize(*MF);
1130 if (LScopes.empty())
1133 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1135 // Make sure that each lexical scope will have a begin/end label.
1136 identifyScopeMarkers();
1138 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1139 // belongs to so that we add to the correct per-cu line table in the
1141 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1142 // FnScope->getScopeNode() and DI->second should represent the same function,
1143 // though they may not be the same MDNode due to inline functions merged in
1144 // LTO where the debug info metadata still differs (either due to distinct
1145 // written differences - two versions of a linkonce_odr function
1146 // written/copied into two separate files, or some sub-optimal metadata that
1147 // isn't structurally identical (see: file path/name info from clang, which
1148 // includes the directory of the cpp file being built, even when the file name
1149 // is absolute (such as an <> lookup header)))
1150 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1151 assert(TheCU && "Unable to find compile unit!");
1152 if (Asm->OutStreamer.hasRawTextSupport())
1153 // Use a single line table if we are generating assembly.
1154 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1156 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1158 // Emit a label for the function so that we have a beginning address.
1159 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1160 // Assumes in correct section after the entry point.
1161 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1163 // Calculate history for local variables.
1164 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1167 // Request labels for the full history.
1168 for (const auto &I : DbgValues) {
1169 const auto &Ranges = I.second;
1173 // The first mention of a function argument gets the FunctionBeginSym
1174 // label, so arguments are visible when breaking at function entry.
1175 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1176 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1177 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1178 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1179 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1180 // Mark all non-overlapping initial pieces.
1181 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1182 DIExpression Piece = I->first->getDebugExpression();
1183 if (std::all_of(Ranges.begin(), I,
1184 [&](DbgValueHistoryMap::InstrRange Pred) {
1185 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1187 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1194 for (const auto &Range : Ranges) {
1195 requestLabelBeforeInsn(Range.first);
1197 requestLabelAfterInsn(Range.second);
1201 PrevInstLoc = DebugLoc();
1202 PrevLabel = FunctionBeginSym;
1204 // Record beginning of function.
1205 PrologEndLoc = findPrologueEndLoc(MF);
1206 if (!PrologEndLoc.isUnknown()) {
1207 DebugLoc FnStartDL =
1208 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1210 FnStartDL.getLine(), FnStartDL.getCol(),
1211 FnStartDL.getScope(MF->getFunction()->getContext()),
1212 // We'd like to list the prologue as "not statements" but GDB behaves
1213 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1214 DWARF2_FLAG_IS_STMT);
1218 // Gather and emit post-function debug information.
1219 void DwarfDebug::endFunction(const MachineFunction *MF) {
1220 assert(CurFn == MF &&
1221 "endFunction should be called with the same function as beginFunction");
1223 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1224 !FunctionDIs.count(MF->getFunction())) {
1225 // If we don't have a lexical scope for this function then there will
1226 // be a hole in the range information. Keep note of this by setting the
1227 // previously used section to nullptr.
1233 // Define end label for subprogram.
1234 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1235 // Assumes in correct section after the entry point.
1236 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1238 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1239 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1241 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1242 DISubprogram SP(FnScope->getScopeNode());
1243 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1245 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1246 collectVariableInfo(TheCU, SP, ProcessedVars);
1248 // Add the range of this function to the list of ranges for the CU.
1249 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1251 // Under -gmlt, skip building the subprogram if there are no inlined
1252 // subroutines inside it.
1253 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1254 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1255 assert(InfoHolder.getScopeVariables().empty());
1256 assert(DbgValues.empty());
1257 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1258 // by a -gmlt CU. Add a test and remove this assertion.
1259 assert(AbstractVariables.empty());
1260 LabelsBeforeInsn.clear();
1261 LabelsAfterInsn.clear();
1262 PrevLabel = nullptr;
1268 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1270 // Construct abstract scopes.
1271 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1272 DISubprogram SP(AScope->getScopeNode());
1273 assert(SP.isSubprogram());
1274 // Collect info for variables that were optimized out.
1275 DIArray Variables = SP.getVariables();
1276 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1277 DIVariable DV(Variables.getElement(i));
1278 assert(DV && DV.isVariable());
1279 if (!ProcessedVars.insert(DV))
1281 ensureAbstractVariableIsCreated(DV, DV.getContext());
1282 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1283 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1285 constructAbstractSubprogramScopeDIE(AScope);
1288 TheCU.constructSubprogramScopeDIE(FnScope);
1291 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1292 // DbgVariables except those that are also in AbstractVariables (since they
1293 // can be used cross-function)
1294 InfoHolder.getScopeVariables().clear();
1296 LabelsBeforeInsn.clear();
1297 LabelsAfterInsn.clear();
1298 PrevLabel = nullptr;
1302 // Register a source line with debug info. Returns the unique label that was
1303 // emitted and which provides correspondence to the source line list.
1304 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1309 unsigned Discriminator = 0;
1310 if (DIScope Scope = DIScope(S)) {
1311 assert(Scope.isScope());
1312 Fn = Scope.getFilename();
1313 Dir = Scope.getDirectory();
1314 if (Scope.isLexicalBlockFile())
1315 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1317 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1318 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1319 .getOrCreateSourceID(Fn, Dir);
1321 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1325 //===----------------------------------------------------------------------===//
1327 //===----------------------------------------------------------------------===//
1329 // Emit initial Dwarf sections with a label at the start of each one.
1330 void DwarfDebug::emitSectionLabels() {
1331 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1333 // Dwarf sections base addresses.
1334 DwarfInfoSectionSym =
1335 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1336 if (useSplitDwarf()) {
1337 DwarfInfoDWOSectionSym =
1338 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1339 DwarfTypesDWOSectionSym =
1340 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1342 DwarfAbbrevSectionSym =
1343 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1344 if (useSplitDwarf())
1345 DwarfAbbrevDWOSectionSym = emitSectionSym(
1346 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1347 if (GenerateARangeSection)
1348 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1350 DwarfLineSectionSym =
1351 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1352 if (GenerateGnuPubSections) {
1353 DwarfGnuPubNamesSectionSym =
1354 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1355 DwarfGnuPubTypesSectionSym =
1356 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1357 } else if (HasDwarfPubSections) {
1358 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1359 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1362 DwarfStrSectionSym =
1363 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1364 if (useSplitDwarf()) {
1365 DwarfStrDWOSectionSym =
1366 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1367 DwarfAddrSectionSym =
1368 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1369 DwarfDebugLocSectionSym =
1370 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1372 DwarfDebugLocSectionSym =
1373 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1374 DwarfDebugRangeSectionSym =
1375 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1378 // Recursively emits a debug information entry.
1379 void DwarfDebug::emitDIE(DIE &Die) {
1380 // Get the abbreviation for this DIE.
1381 const DIEAbbrev &Abbrev = Die.getAbbrev();
1383 // Emit the code (index) for the abbreviation.
1384 if (Asm->isVerbose())
1385 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1386 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1387 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1388 dwarf::TagString(Abbrev.getTag()));
1389 Asm->EmitULEB128(Abbrev.getNumber());
1391 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1392 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1394 // Emit the DIE attribute values.
1395 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1396 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1397 dwarf::Form Form = AbbrevData[i].getForm();
1398 assert(Form && "Too many attributes for DIE (check abbreviation)");
1400 if (Asm->isVerbose()) {
1401 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1402 if (Attr == dwarf::DW_AT_accessibility)
1403 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1404 cast<DIEInteger>(Values[i])->getValue()));
1407 // Emit an attribute using the defined form.
1408 Values[i]->EmitValue(Asm, Form);
1411 // Emit the DIE children if any.
1412 if (Abbrev.hasChildren()) {
1413 for (auto &Child : Die.getChildren())
1416 Asm->OutStreamer.AddComment("End Of Children Mark");
1421 // Emit the debug info section.
1422 void DwarfDebug::emitDebugInfo() {
1423 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1425 Holder.emitUnits(DwarfAbbrevSectionSym);
1428 // Emit the abbreviation section.
1429 void DwarfDebug::emitAbbreviations() {
1430 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1432 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1435 // Emit the last address of the section and the end of the line matrix.
1436 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1437 // Define last address of section.
1438 Asm->OutStreamer.AddComment("Extended Op");
1441 Asm->OutStreamer.AddComment("Op size");
1442 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1443 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1444 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1446 Asm->OutStreamer.AddComment("Section end label");
1448 Asm->OutStreamer.EmitSymbolValue(
1449 Asm->GetTempSymbol("section_end", SectionEnd),
1450 Asm->getDataLayout().getPointerSize());
1452 // Mark end of matrix.
1453 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1459 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1460 StringRef TableName, StringRef SymName) {
1461 Accel.FinalizeTable(Asm, TableName);
1462 Asm->OutStreamer.SwitchSection(Section);
1463 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1464 Asm->OutStreamer.EmitLabel(SectionBegin);
1466 // Emit the full data.
1467 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1470 // Emit visible names into a hashed accelerator table section.
1471 void DwarfDebug::emitAccelNames() {
1472 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1473 "Names", "names_begin");
1476 // Emit objective C classes and categories into a hashed accelerator table
1478 void DwarfDebug::emitAccelObjC() {
1479 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1480 "ObjC", "objc_begin");
1483 // Emit namespace dies into a hashed accelerator table.
1484 void DwarfDebug::emitAccelNamespaces() {
1485 emitAccel(AccelNamespace,
1486 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1487 "namespac", "namespac_begin");
1490 // Emit type dies into a hashed accelerator table.
1491 void DwarfDebug::emitAccelTypes() {
1492 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1493 "types", "types_begin");
1496 // Public name handling.
1497 // The format for the various pubnames:
1499 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1500 // for the DIE that is named.
1502 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1503 // into the CU and the index value is computed according to the type of value
1504 // for the DIE that is named.
1506 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1507 // it's the offset within the debug_info/debug_types dwo section, however, the
1508 // reference in the pubname header doesn't change.
1510 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1511 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1513 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1515 // We could have a specification DIE that has our most of our knowledge,
1516 // look for that now.
1517 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1519 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1520 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1521 Linkage = dwarf::GIEL_EXTERNAL;
1522 } else if (Die->findAttribute(dwarf::DW_AT_external))
1523 Linkage = dwarf::GIEL_EXTERNAL;
1525 switch (Die->getTag()) {
1526 case dwarf::DW_TAG_class_type:
1527 case dwarf::DW_TAG_structure_type:
1528 case dwarf::DW_TAG_union_type:
1529 case dwarf::DW_TAG_enumeration_type:
1530 return dwarf::PubIndexEntryDescriptor(
1531 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1532 ? dwarf::GIEL_STATIC
1533 : dwarf::GIEL_EXTERNAL);
1534 case dwarf::DW_TAG_typedef:
1535 case dwarf::DW_TAG_base_type:
1536 case dwarf::DW_TAG_subrange_type:
1537 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1538 case dwarf::DW_TAG_namespace:
1539 return dwarf::GIEK_TYPE;
1540 case dwarf::DW_TAG_subprogram:
1541 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1542 case dwarf::DW_TAG_constant:
1543 case dwarf::DW_TAG_variable:
1544 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1545 case dwarf::DW_TAG_enumerator:
1546 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1547 dwarf::GIEL_STATIC);
1549 return dwarf::GIEK_NONE;
1553 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1555 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1556 const MCSection *PSec =
1557 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1558 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1560 emitDebugPubSection(GnuStyle, PSec, "Names",
1561 &DwarfCompileUnit::getGlobalNames);
1564 void DwarfDebug::emitDebugPubSection(
1565 bool GnuStyle, const MCSection *PSec, StringRef Name,
1566 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1567 for (const auto &NU : CUMap) {
1568 DwarfCompileUnit *TheU = NU.second;
1570 const auto &Globals = (TheU->*Accessor)();
1572 if (Globals.empty())
1575 if (auto *Skeleton = TheU->getSkeleton())
1577 unsigned ID = TheU->getUniqueID();
1579 // Start the dwarf pubnames section.
1580 Asm->OutStreamer.SwitchSection(PSec);
1583 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1584 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1585 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1586 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1588 Asm->OutStreamer.EmitLabel(BeginLabel);
1590 Asm->OutStreamer.AddComment("DWARF Version");
1591 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1593 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1594 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1596 Asm->OutStreamer.AddComment("Compilation Unit Length");
1597 Asm->EmitInt32(TheU->getLength());
1599 // Emit the pubnames for this compilation unit.
1600 for (const auto &GI : Globals) {
1601 const char *Name = GI.getKeyData();
1602 const DIE *Entity = GI.second;
1604 Asm->OutStreamer.AddComment("DIE offset");
1605 Asm->EmitInt32(Entity->getOffset());
1608 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1609 Asm->OutStreamer.AddComment(
1610 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1611 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1612 Asm->EmitInt8(Desc.toBits());
1615 Asm->OutStreamer.AddComment("External Name");
1616 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1619 Asm->OutStreamer.AddComment("End Mark");
1621 Asm->OutStreamer.EmitLabel(EndLabel);
1625 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1626 const MCSection *PSec =
1627 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1628 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1630 emitDebugPubSection(GnuStyle, PSec, "Types",
1631 &DwarfCompileUnit::getGlobalTypes);
1634 // Emit visible names into a debug str section.
1635 void DwarfDebug::emitDebugStr() {
1636 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1637 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1640 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1641 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1642 const DITypeIdentifierMap &Map,
1643 ArrayRef<DebugLocEntry::Value> Values) {
1644 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1645 return P.isVariablePiece();
1646 }) && "all values are expected to be pieces");
1647 assert(std::is_sorted(Values.begin(), Values.end()) &&
1648 "pieces are expected to be sorted");
1650 unsigned Offset = 0;
1651 for (auto Piece : Values) {
1652 DIExpression Expr = Piece.getExpression();
1653 unsigned PieceOffset = Expr.getPieceOffset();
1654 unsigned PieceSize = Expr.getPieceSize();
1655 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1656 if (Offset < PieceOffset) {
1657 // The DWARF spec seriously mandates pieces with no locations for gaps.
1658 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1659 Offset += PieceOffset-Offset;
1662 Offset += PieceSize;
1664 const unsigned SizeOfByte = 8;
1666 DIVariable Var = Piece.getVariable();
1667 assert(!Var.isIndirect() && "indirect address for piece");
1668 unsigned VarSize = Var.getSizeInBits(Map);
1669 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1670 && "piece is larger than or outside of variable");
1671 assert(PieceSize*SizeOfByte != VarSize
1672 && "piece covers entire variable");
1674 if (Piece.isLocation() && Piece.getLoc().isReg())
1675 Asm->EmitDwarfRegOpPiece(Streamer,
1677 PieceSize*SizeOfByte);
1679 emitDebugLocValue(Streamer, Piece);
1680 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1686 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1687 const DebugLocEntry &Entry) {
1688 const DebugLocEntry::Value Value = Entry.getValues()[0];
1689 if (Value.isVariablePiece())
1690 // Emit all pieces that belong to the same variable and range.
1691 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1693 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1694 emitDebugLocValue(Streamer, Value);
1697 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1698 const DebugLocEntry::Value &Value) {
1699 DIVariable DV = Value.getVariable();
1701 if (Value.isInt()) {
1702 DIBasicType BTy(resolve(DV.getType()));
1703 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1704 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1705 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1706 Streamer.EmitSLEB128(Value.getInt());
1708 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1709 Streamer.EmitULEB128(Value.getInt());
1711 } else if (Value.isLocation()) {
1712 MachineLocation Loc = Value.getLoc();
1713 DIExpression Expr = Value.getExpression();
1716 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1718 // Complex address entry.
1719 unsigned N = Expr.getNumElements();
1721 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1722 if (Loc.getOffset()) {
1724 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1725 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1726 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1727 Streamer.EmitSLEB128(Expr.getElement(1));
1729 // If first address element is OpPlus then emit
1730 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1731 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1732 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1736 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1739 // Emit remaining complex address elements.
1740 for (; i < N; ++i) {
1741 uint64_t Element = Expr.getElement(i);
1742 if (Element == dwarf::DW_OP_plus) {
1743 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1744 Streamer.EmitULEB128(Expr.getElement(++i));
1745 } else if (Element == dwarf::DW_OP_deref) {
1747 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1748 } else if (Element == dwarf::DW_OP_piece) {
1750 // handled in emitDebugLocEntry.
1752 llvm_unreachable("unknown Opcode found in complex address");
1756 // else ... ignore constant fp. There is not any good way to
1757 // to represent them here in dwarf.
1761 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1762 Asm->OutStreamer.AddComment("Loc expr size");
1763 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1764 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1765 Asm->EmitLabelDifference(end, begin, 2);
1766 Asm->OutStreamer.EmitLabel(begin);
1768 APByteStreamer Streamer(*Asm);
1769 emitDebugLocEntry(Streamer, Entry);
1771 Asm->OutStreamer.EmitLabel(end);
1774 // Emit locations into the debug loc section.
1775 void DwarfDebug::emitDebugLoc() {
1776 // Start the dwarf loc section.
1777 Asm->OutStreamer.SwitchSection(
1778 Asm->getObjFileLowering().getDwarfLocSection());
1779 unsigned char Size = Asm->getDataLayout().getPointerSize();
1780 for (const auto &DebugLoc : DotDebugLocEntries) {
1781 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1782 const DwarfCompileUnit *CU = DebugLoc.CU;
1783 for (const auto &Entry : DebugLoc.List) {
1784 // Set up the range. This range is relative to the entry point of the
1785 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1786 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1787 if (auto *Base = CU->getBaseAddress()) {
1788 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1789 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1791 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1792 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1795 emitDebugLocEntryLocation(Entry);
1797 Asm->OutStreamer.EmitIntValue(0, Size);
1798 Asm->OutStreamer.EmitIntValue(0, Size);
1802 void DwarfDebug::emitDebugLocDWO() {
1803 Asm->OutStreamer.SwitchSection(
1804 Asm->getObjFileLowering().getDwarfLocDWOSection());
1805 for (const auto &DebugLoc : DotDebugLocEntries) {
1806 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1807 for (const auto &Entry : DebugLoc.List) {
1808 // Just always use start_length for now - at least that's one address
1809 // rather than two. We could get fancier and try to, say, reuse an
1810 // address we know we've emitted elsewhere (the start of the function?
1811 // The start of the CU or CU subrange that encloses this range?)
1812 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1813 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1814 Asm->EmitULEB128(idx);
1815 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1817 emitDebugLocEntryLocation(Entry);
1819 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1824 const MCSymbol *Start, *End;
1827 // Emit a debug aranges section, containing a CU lookup for any
1828 // address we can tie back to a CU.
1829 void DwarfDebug::emitDebugARanges() {
1830 // Start the dwarf aranges section.
1831 Asm->OutStreamer.SwitchSection(
1832 Asm->getObjFileLowering().getDwarfARangesSection());
1834 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1838 // Build a list of sections used.
1839 std::vector<const MCSection *> Sections;
1840 for (const auto &it : SectionMap) {
1841 const MCSection *Section = it.first;
1842 Sections.push_back(Section);
1845 // Sort the sections into order.
1846 // This is only done to ensure consistent output order across different runs.
1847 std::sort(Sections.begin(), Sections.end(), SectionSort);
1849 // Build a set of address spans, sorted by CU.
1850 for (const MCSection *Section : Sections) {
1851 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1852 if (List.size() < 2)
1855 // Sort the symbols by offset within the section.
1856 std::sort(List.begin(), List.end(),
1857 [&](const SymbolCU &A, const SymbolCU &B) {
1858 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1859 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1861 // Symbols with no order assigned should be placed at the end.
1862 // (e.g. section end labels)
1870 // If we have no section (e.g. common), just write out
1871 // individual spans for each symbol.
1873 for (const SymbolCU &Cur : List) {
1875 Span.Start = Cur.Sym;
1878 Spans[Cur.CU].push_back(Span);
1881 // Build spans between each label.
1882 const MCSymbol *StartSym = List[0].Sym;
1883 for (size_t n = 1, e = List.size(); n < e; n++) {
1884 const SymbolCU &Prev = List[n - 1];
1885 const SymbolCU &Cur = List[n];
1887 // Try and build the longest span we can within the same CU.
1888 if (Cur.CU != Prev.CU) {
1890 Span.Start = StartSym;
1892 Spans[Prev.CU].push_back(Span);
1899 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1901 // Build a list of CUs used.
1902 std::vector<DwarfCompileUnit *> CUs;
1903 for (const auto &it : Spans) {
1904 DwarfCompileUnit *CU = it.first;
1908 // Sort the CU list (again, to ensure consistent output order).
1909 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1910 return A->getUniqueID() < B->getUniqueID();
1913 // Emit an arange table for each CU we used.
1914 for (DwarfCompileUnit *CU : CUs) {
1915 std::vector<ArangeSpan> &List = Spans[CU];
1917 // Describe the skeleton CU's offset and length, not the dwo file's.
1918 if (auto *Skel = CU->getSkeleton())
1921 // Emit size of content not including length itself.
1922 unsigned ContentSize =
1923 sizeof(int16_t) + // DWARF ARange version number
1924 sizeof(int32_t) + // Offset of CU in the .debug_info section
1925 sizeof(int8_t) + // Pointer Size (in bytes)
1926 sizeof(int8_t); // Segment Size (in bytes)
1928 unsigned TupleSize = PtrSize * 2;
1930 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1932 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1934 ContentSize += Padding;
1935 ContentSize += (List.size() + 1) * TupleSize;
1937 // For each compile unit, write the list of spans it covers.
1938 Asm->OutStreamer.AddComment("Length of ARange Set");
1939 Asm->EmitInt32(ContentSize);
1940 Asm->OutStreamer.AddComment("DWARF Arange version number");
1941 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1942 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1943 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1944 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1945 Asm->EmitInt8(PtrSize);
1946 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1949 Asm->OutStreamer.EmitFill(Padding, 0xff);
1951 for (const ArangeSpan &Span : List) {
1952 Asm->EmitLabelReference(Span.Start, PtrSize);
1954 // Calculate the size as being from the span start to it's end.
1956 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1958 // For symbols without an end marker (e.g. common), we
1959 // write a single arange entry containing just that one symbol.
1960 uint64_t Size = SymSize[Span.Start];
1964 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1968 Asm->OutStreamer.AddComment("ARange terminator");
1969 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1970 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1974 // Emit visible names into a debug ranges section.
1975 void DwarfDebug::emitDebugRanges() {
1976 // Start the dwarf ranges section.
1977 Asm->OutStreamer.SwitchSection(
1978 Asm->getObjFileLowering().getDwarfRangesSection());
1980 // Size for our labels.
1981 unsigned char Size = Asm->getDataLayout().getPointerSize();
1983 // Grab the specific ranges for the compile units in the module.
1984 for (const auto &I : CUMap) {
1985 DwarfCompileUnit *TheCU = I.second;
1987 // Iterate over the misc ranges for the compile units in the module.
1988 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1989 // Emit our symbol so we can find the beginning of the range.
1990 Asm->OutStreamer.EmitLabel(List.getSym());
1992 for (const RangeSpan &Range : List.getRanges()) {
1993 const MCSymbol *Begin = Range.getStart();
1994 const MCSymbol *End = Range.getEnd();
1995 assert(Begin && "Range without a begin symbol?");
1996 assert(End && "Range without an end symbol?");
1997 if (auto *Base = TheCU->getBaseAddress()) {
1998 Asm->EmitLabelDifference(Begin, Base, Size);
1999 Asm->EmitLabelDifference(End, Base, Size);
2001 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2002 Asm->OutStreamer.EmitSymbolValue(End, Size);
2006 // And terminate the list with two 0 values.
2007 Asm->OutStreamer.EmitIntValue(0, Size);
2008 Asm->OutStreamer.EmitIntValue(0, Size);
2013 // DWARF5 Experimental Separate Dwarf emitters.
2015 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2016 std::unique_ptr<DwarfUnit> NewU) {
2017 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
2018 U.getCUNode().getSplitDebugFilename());
2020 if (!CompilationDir.empty())
2021 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2023 addGnuPubAttributes(*NewU, Die);
2025 SkeletonHolder.addUnit(std::move(NewU));
2028 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2029 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2030 // DW_AT_addr_base, DW_AT_ranges_base.
2031 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2033 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2034 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2035 DwarfCompileUnit &NewCU = *OwnedUnit;
2036 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2037 DwarfInfoSectionSym);
2039 NewCU.initStmtList(DwarfLineSectionSym);
2041 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2046 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2047 // compile units that would normally be in debug_info.
2048 void DwarfDebug::emitDebugInfoDWO() {
2049 assert(useSplitDwarf() && "No split dwarf debug info?");
2050 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2051 // emit relocations into the dwo file.
2052 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2055 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2056 // abbreviations for the .debug_info.dwo section.
2057 void DwarfDebug::emitDebugAbbrevDWO() {
2058 assert(useSplitDwarf() && "No split dwarf?");
2059 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2062 void DwarfDebug::emitDebugLineDWO() {
2063 assert(useSplitDwarf() && "No split dwarf?");
2064 Asm->OutStreamer.SwitchSection(
2065 Asm->getObjFileLowering().getDwarfLineDWOSection());
2066 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2069 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2070 // string section and is identical in format to traditional .debug_str
2072 void DwarfDebug::emitDebugStrDWO() {
2073 assert(useSplitDwarf() && "No split dwarf?");
2074 const MCSection *OffSec =
2075 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2076 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2080 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2081 if (!useSplitDwarf())
2084 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2085 return &SplitTypeUnitFileTable;
2088 static uint64_t makeTypeSignature(StringRef Identifier) {
2090 Hash.update(Identifier);
2091 // ... take the least significant 8 bytes and return those. Our MD5
2092 // implementation always returns its results in little endian, swap bytes
2094 MD5::MD5Result Result;
2096 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2099 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2100 StringRef Identifier, DIE &RefDie,
2101 DICompositeType CTy) {
2102 // Fast path if we're building some type units and one has already used the
2103 // address pool we know we're going to throw away all this work anyway, so
2104 // don't bother building dependent types.
2105 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2108 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2110 CU.addDIETypeSignature(RefDie, *TU);
2114 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2115 AddrPool.resetUsedFlag();
2117 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2118 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2119 this, &InfoHolder, getDwoLineTable(CU));
2120 DwarfTypeUnit &NewTU = *OwnedUnit;
2121 DIE &UnitDie = NewTU.getUnitDie();
2123 TypeUnitsUnderConstruction.push_back(
2124 std::make_pair(std::move(OwnedUnit), CTy));
2126 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2129 uint64_t Signature = makeTypeSignature(Identifier);
2130 NewTU.setTypeSignature(Signature);
2132 if (useSplitDwarf())
2133 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2135 CU.applyStmtList(UnitDie);
2137 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2140 NewTU.setType(NewTU.createTypeDIE(CTy));
2143 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2144 TypeUnitsUnderConstruction.clear();
2146 // Types referencing entries in the address table cannot be placed in type
2148 if (AddrPool.hasBeenUsed()) {
2150 // Remove all the types built while building this type.
2151 // This is pessimistic as some of these types might not be dependent on
2152 // the type that used an address.
2153 for (const auto &TU : TypeUnitsToAdd)
2154 DwarfTypeUnits.erase(TU.second);
2156 // Construct this type in the CU directly.
2157 // This is inefficient because all the dependent types will be rebuilt
2158 // from scratch, including building them in type units, discovering that
2159 // they depend on addresses, throwing them out and rebuilding them.
2160 CU.constructTypeDIE(RefDie, CTy);
2164 // If the type wasn't dependent on fission addresses, finish adding the type
2165 // and all its dependent types.
2166 for (auto &TU : TypeUnitsToAdd)
2167 InfoHolder.addUnit(std::move(TU.first));
2169 CU.addDIETypeSignature(RefDie, NewTU);
2172 // Accelerator table mutators - add each name along with its companion
2173 // DIE to the proper table while ensuring that the name that we're going
2174 // to reference is in the string table. We do this since the names we
2175 // add may not only be identical to the names in the DIE.
2176 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2177 if (!useDwarfAccelTables())
2179 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2183 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2184 if (!useDwarfAccelTables())
2186 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2190 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2191 if (!useDwarfAccelTables())
2193 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2197 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2198 if (!useDwarfAccelTables())
2200 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),