1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfDebug.h"
16 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.h"
20 #include "DwarfUnit.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 //===----------------------------------------------------------------------===//
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
151 uint16_t tag = Ty.getTag();
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
173 InfoHolder(A, *this, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
204 HasSplitDwarf = SplitDwarf == Enable;
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
209 HasDwarfPubSections = DwarfPubSections == Enable;
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
224 DwarfDebug::~DwarfDebug() { }
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
247 return Name.find(") ") != StringRef::npos;
250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
267 // Helper for sorting sections into a stable output order.
268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
281 addAccelName(SP.getName(), Die);
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
288 // If this is an Objective-C selector name add it to the ObjC accelerator
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
334 assert(Scope && Scope->getScopeNode());
335 assert(Scope->isAbstractScope());
336 assert(!Scope->getInlinedAt());
338 const MDNode *SP = Scope->getScopeNode();
340 ProcessedSPNodes.insert(SP);
342 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
343 // was inlined from another compile unit.
344 SPMap[SP]->constructAbstractSubprogramScopeDIE(Scope);
347 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
348 if (!GenerateGnuPubSections)
351 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
354 // Create new DwarfCompileUnit for the given metadata node with tag
355 // DW_TAG_compile_unit.
356 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
357 StringRef FN = DIUnit.getFilename();
358 CompilationDir = DIUnit.getDirectory();
360 auto OwnedUnit = make_unique<DwarfCompileUnit>(
361 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
362 DwarfCompileUnit &NewCU = *OwnedUnit;
363 DIE &Die = NewCU.getUnitDie();
364 InfoHolder.addUnit(std::move(OwnedUnit));
366 // LTO with assembly output shares a single line table amongst multiple CUs.
367 // To avoid the compilation directory being ambiguous, let the line table
368 // explicitly describe the directory of all files, never relying on the
369 // compilation directory.
370 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
371 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
372 NewCU.getUniqueID(), CompilationDir);
374 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
375 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
376 DIUnit.getLanguage());
377 NewCU.addString(Die, dwarf::DW_AT_name, FN);
379 if (!useSplitDwarf()) {
380 NewCU.initStmtList(DwarfLineSectionSym);
382 // If we're using split dwarf the compilation dir is going to be in the
383 // skeleton CU and so we don't need to duplicate it here.
384 if (!CompilationDir.empty())
385 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
387 addGnuPubAttributes(NewCU, Die);
390 if (DIUnit.isOptimized())
391 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
393 StringRef Flags = DIUnit.getFlags();
395 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
397 if (unsigned RVer = DIUnit.getRunTimeVersion())
398 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
399 dwarf::DW_FORM_data1, RVer);
401 if (useSplitDwarf()) {
402 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
403 DwarfInfoDWOSectionSym);
404 NewCU.setSkeleton(constructSkeletonCU(NewCU));
406 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
407 DwarfInfoSectionSym);
409 CUMap.insert(std::make_pair(DIUnit, &NewCU));
410 CUDieMap.insert(std::make_pair(&Die, &NewCU));
414 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
416 DIImportedEntity Module(N);
417 assert(Module.Verify());
418 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
419 D->addChild(TheCU.constructImportedEntityDIE(Module));
422 // Emit all Dwarf sections that should come prior to the content. Create
423 // global DIEs and emit initial debug info sections. This is invoked by
424 // the target AsmPrinter.
425 void DwarfDebug::beginModule() {
426 if (DisableDebugInfoPrinting)
429 const Module *M = MMI->getModule();
431 FunctionDIs = makeSubprogramMap(*M);
433 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
436 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
438 // Emit initial sections so we can reference labels later.
441 SingleCU = CU_Nodes->getNumOperands() == 1;
443 for (MDNode *N : CU_Nodes->operands()) {
444 DICompileUnit CUNode(N);
445 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
446 DIArray ImportedEntities = CUNode.getImportedEntities();
447 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
448 ScopesWithImportedEntities.push_back(std::make_pair(
449 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
450 ImportedEntities.getElement(i)));
451 std::sort(ScopesWithImportedEntities.begin(),
452 ScopesWithImportedEntities.end(), less_first());
453 DIArray GVs = CUNode.getGlobalVariables();
454 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
455 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
456 DIArray SPs = CUNode.getSubprograms();
457 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
458 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
459 DIArray EnumTypes = CUNode.getEnumTypes();
460 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
461 DIType Ty(EnumTypes.getElement(i));
462 // The enum types array by design contains pointers to
463 // MDNodes rather than DIRefs. Unique them here.
464 DIType UniqueTy(resolve(Ty.getRef()));
465 CU.getOrCreateTypeDIE(UniqueTy);
467 DIArray RetainedTypes = CUNode.getRetainedTypes();
468 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
469 DIType Ty(RetainedTypes.getElement(i));
470 // The retained types array by design contains pointers to
471 // MDNodes rather than DIRefs. Unique them here.
472 DIType UniqueTy(resolve(Ty.getRef()));
473 CU.getOrCreateTypeDIE(UniqueTy);
475 // Emit imported_modules last so that the relevant context is already
477 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
478 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
481 // Tell MMI that we have debug info.
482 MMI->setDebugInfoAvailability(true);
484 // Prime section data.
485 SectionMap[Asm->getObjFileLowering().getTextSection()];
488 void DwarfDebug::finishVariableDefinitions() {
489 for (const auto &Var : ConcreteVariables) {
490 DIE *VariableDie = Var->getDIE();
492 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
493 // in the ConcreteVariables list, rather than looking it up again here.
494 // DIE::getUnit isn't simple - it walks parent pointers, etc.
495 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
497 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
498 if (AbsVar && AbsVar->getDIE()) {
499 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
502 Unit->applyVariableAttributes(*Var, *VariableDie);
506 void DwarfDebug::finishSubprogramDefinitions() {
507 for (const auto &P : SPMap)
508 P.second->finishSubprogramDefinition(DISubprogram(P.first));
512 // Collect info for variables that were optimized out.
513 void DwarfDebug::collectDeadVariables() {
514 const Module *M = MMI->getModule();
516 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
517 for (MDNode *N : CU_Nodes->operands()) {
518 DICompileUnit TheCU(N);
519 // Construct subprogram DIE and add variables DIEs.
520 DwarfCompileUnit *SPCU =
521 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
522 assert(SPCU && "Unable to find Compile Unit!");
523 DIArray Subprograms = TheCU.getSubprograms();
524 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
525 DISubprogram SP(Subprograms.getElement(i));
526 if (ProcessedSPNodes.count(SP) != 0)
528 SPCU->collectDeadVariables(SP);
534 void DwarfDebug::finalizeModuleInfo() {
535 finishSubprogramDefinitions();
537 finishVariableDefinitions();
539 // Collect info for variables that were optimized out.
540 collectDeadVariables();
542 // Handle anything that needs to be done on a per-unit basis after
543 // all other generation.
544 for (const auto &TheU : getUnits()) {
545 // Emit DW_AT_containing_type attribute to connect types with their
546 // vtable holding type.
547 TheU->constructContainingTypeDIEs();
549 // Add CU specific attributes if we need to add any.
550 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
551 // If we're splitting the dwarf out now that we've got the entire
552 // CU then add the dwo id to it.
553 DwarfCompileUnit *SkCU = TheU->getSkeleton();
554 if (useSplitDwarf()) {
555 // Emit a unique identifier for this CU.
556 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
557 TheU->addUInt(TheU->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 (!TheU->getRangeLists().empty())
568 SkCU->addSectionLabel(
569 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
570 DwarfDebugRangeSectionSym, 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 =
580 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
581 unsigned NumRanges = TheU->getRanges().size();
584 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
585 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
586 DwarfDebugRangeSectionSym);
588 // A DW_AT_low_pc attribute may also be specified in combination with
589 // DW_AT_ranges to specify the default base address for use in
590 // location lists (see Section 2.6.2) and range lists (see Section
592 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
595 RangeSpan &Range = TheU->getRanges().back();
596 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
602 // Compute DIE offsets and sizes.
603 InfoHolder.computeSizeAndOffsets();
605 SkeletonHolder.computeSizeAndOffsets();
608 void DwarfDebug::endSections() {
609 // Filter labels by section.
610 for (const SymbolCU &SCU : ArangeLabels) {
611 if (SCU.Sym->isInSection()) {
612 // Make a note of this symbol and it's section.
613 const MCSection *Section = &SCU.Sym->getSection();
614 if (!Section->getKind().isMetadata())
615 SectionMap[Section].push_back(SCU);
617 // Some symbols (e.g. common/bss on mach-o) can have no section but still
618 // appear in the output. This sucks as we rely on sections to build
619 // arange spans. We can do it without, but it's icky.
620 SectionMap[nullptr].push_back(SCU);
624 // Build a list of sections used.
625 std::vector<const MCSection *> Sections;
626 for (const auto &it : SectionMap) {
627 const MCSection *Section = it.first;
628 Sections.push_back(Section);
631 // Sort the sections into order.
632 // This is only done to ensure consistent output order across different runs.
633 std::sort(Sections.begin(), Sections.end(), SectionSort);
635 // Add terminating symbols for each section.
636 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
637 const MCSection *Section = Sections[ID];
638 MCSymbol *Sym = nullptr;
641 // We can't call MCSection::getLabelEndName, as it's only safe to do so
642 // if we know the section name up-front. For user-created sections, the
643 // resulting label may not be valid to use as a label. (section names can
644 // use a greater set of characters on some systems)
645 Sym = Asm->GetTempSymbol("debug_end", ID);
646 Asm->OutStreamer.SwitchSection(Section);
647 Asm->OutStreamer.EmitLabel(Sym);
650 // Insert a final terminator.
651 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
655 // Emit all Dwarf sections that should come after the content.
656 void DwarfDebug::endModule() {
657 assert(CurFn == nullptr);
658 assert(CurMI == nullptr);
660 // If we aren't actually generating debug info (check beginModule -
661 // conditionalized on !DisableDebugInfoPrinting and the presence of the
662 // llvm.dbg.cu metadata node)
663 if (!DwarfInfoSectionSym)
666 // End any existing sections.
667 // TODO: Does this need to happen?
670 // Finalize the debug info for the module.
671 finalizeModuleInfo();
675 // Emit all the DIEs into a debug info section.
678 // Corresponding abbreviations into a abbrev section.
681 // Emit info into a debug aranges section.
682 if (GenerateARangeSection)
685 // Emit info into a debug ranges section.
688 if (useSplitDwarf()) {
691 emitDebugAbbrevDWO();
694 // Emit DWO addresses.
695 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
697 // Emit info into a debug loc section.
700 // Emit info into the dwarf accelerator table sections.
701 if (useDwarfAccelTables()) {
704 emitAccelNamespaces();
708 // Emit the pubnames and pubtypes sections if requested.
709 if (HasDwarfPubSections) {
710 emitDebugPubNames(GenerateGnuPubSections);
711 emitDebugPubTypes(GenerateGnuPubSections);
716 AbstractVariables.clear();
719 // Find abstract variable, if any, associated with Var.
720 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
721 DIVariable &Cleansed) {
722 LLVMContext &Ctx = DV->getContext();
723 // More then one inlined variable corresponds to one abstract variable.
724 // FIXME: This duplication of variables when inlining should probably be
725 // removed. It's done to allow each DIVariable to describe its location
726 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
727 // make it accurate then remove this duplication/cleansing stuff.
728 Cleansed = cleanseInlinedVariable(DV, Ctx);
729 auto I = AbstractVariables.find(Cleansed);
730 if (I != AbstractVariables.end())
731 return I->second.get();
735 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
737 return getExistingAbstractVariable(DV, Cleansed);
740 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
741 LexicalScope *Scope) {
742 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
743 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
744 AbstractVariables[Var] = std::move(AbsDbgVariable);
747 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
748 const MDNode *ScopeNode) {
749 DIVariable Cleansed = DV;
750 if (getExistingAbstractVariable(DV, Cleansed))
753 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
757 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
758 const MDNode *ScopeNode) {
759 DIVariable Cleansed = DV;
760 if (getExistingAbstractVariable(DV, Cleansed))
763 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
764 createAbstractVariable(Cleansed, Scope);
767 // Collect variable information from side table maintained by MMI.
768 void DwarfDebug::collectVariableInfoFromMMITable(
769 SmallPtrSetImpl<const MDNode *> &Processed) {
770 for (const auto &VI : MMI->getVariableDbgInfo()) {
773 Processed.insert(VI.Var);
774 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
776 // If variable scope is not found then skip this variable.
780 DIVariable DV(VI.Var);
781 DIExpression Expr(VI.Expr);
782 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
783 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
784 DbgVariable *RegVar = ConcreteVariables.back().get();
785 RegVar->setFrameIndex(VI.Slot);
786 InfoHolder.addScopeVariable(Scope, RegVar);
790 // Get .debug_loc entry for the instruction range starting at MI.
791 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
792 const MDNode *Expr = MI->getDebugExpression();
793 const MDNode *Var = MI->getDebugVariable();
795 assert(MI->getNumOperands() == 4);
796 if (MI->getOperand(0).isReg()) {
797 MachineLocation MLoc;
798 // If the second operand is an immediate, this is a
799 // register-indirect address.
800 if (!MI->getOperand(1).isImm())
801 MLoc.set(MI->getOperand(0).getReg());
803 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
804 return DebugLocEntry::Value(Var, Expr, MLoc);
806 if (MI->getOperand(0).isImm())
807 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
808 if (MI->getOperand(0).isFPImm())
809 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
810 if (MI->getOperand(0).isCImm())
811 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
813 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
816 /// Determine whether two variable pieces overlap.
817 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
818 if (!P1.isVariablePiece() || !P2.isVariablePiece())
820 unsigned l1 = P1.getPieceOffset();
821 unsigned l2 = P2.getPieceOffset();
822 unsigned r1 = l1 + P1.getPieceSize();
823 unsigned r2 = l2 + P2.getPieceSize();
824 // True where [l1,r1[ and [r1,r2[ overlap.
825 return (l1 < r2) && (l2 < r1);
828 /// Build the location list for all DBG_VALUEs in the function that
829 /// describe the same variable. If the ranges of several independent
830 /// pieces of the same variable overlap partially, split them up and
831 /// combine the ranges. The resulting DebugLocEntries are will have
832 /// strict monotonically increasing begin addresses and will never
837 // Ranges History [var, loc, piece ofs size]
838 // 0 | [x, (reg0, piece 0, 32)]
839 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
841 // 3 | [clobber reg0]
842 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
846 // [0-1] [x, (reg0, piece 0, 32)]
847 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
848 // [3-4] [x, (reg1, piece 32, 32)]
849 // [4- ] [x, (mem, piece 0, 64)]
851 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
852 const DbgValueHistoryMap::InstrRanges &Ranges) {
853 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
855 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
856 const MachineInstr *Begin = I->first;
857 const MachineInstr *End = I->second;
858 assert(Begin->isDebugValue() && "Invalid History entry");
860 // Check if a variable is inaccessible in this range.
861 if (Begin->getNumOperands() > 1 &&
862 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
867 // If this piece overlaps with any open ranges, truncate them.
868 DIExpression DIExpr = Begin->getDebugExpression();
869 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
870 [&](DebugLocEntry::Value R) {
871 return piecesOverlap(DIExpr, R.getExpression());
873 OpenRanges.erase(Last, OpenRanges.end());
875 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
876 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
878 const MCSymbol *EndLabel;
880 EndLabel = getLabelAfterInsn(End);
881 else if (std::next(I) == Ranges.end())
882 EndLabel = FunctionEndSym;
884 EndLabel = getLabelBeforeInsn(std::next(I)->first);
885 assert(EndLabel && "Forgot label after instruction ending a range!");
887 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
889 auto Value = getDebugLocValue(Begin);
890 DebugLocEntry Loc(StartLabel, EndLabel, Value);
891 bool couldMerge = false;
893 // If this is a piece, it may belong to the current DebugLocEntry.
894 if (DIExpr.isVariablePiece()) {
895 // Add this value to the list of open ranges.
896 OpenRanges.push_back(Value);
898 // Attempt to add the piece to the last entry.
899 if (!DebugLoc.empty())
900 if (DebugLoc.back().MergeValues(Loc))
905 // Need to add a new DebugLocEntry. Add all values from still
906 // valid non-overlapping pieces.
907 if (OpenRanges.size())
908 Loc.addValues(OpenRanges);
910 DebugLoc.push_back(std::move(Loc));
913 // Attempt to coalesce the ranges of two otherwise identical
915 auto CurEntry = DebugLoc.rbegin();
916 auto PrevEntry = std::next(CurEntry);
917 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
921 dbgs() << CurEntry->getValues().size() << " Values:\n";
922 for (auto Value : CurEntry->getValues()) {
923 Value.getVariable()->dump();
924 Value.getExpression()->dump();
932 // Find variables for each lexical scope.
934 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
935 SmallPtrSetImpl<const MDNode *> &Processed) {
936 // Grab the variable info that was squirreled away in the MMI side-table.
937 collectVariableInfoFromMMITable(Processed);
939 for (const auto &I : DbgValues) {
940 DIVariable DV(I.first);
941 if (Processed.count(DV))
944 // Instruction ranges, specifying where DV is accessible.
945 const auto &Ranges = I.second;
949 LexicalScope *Scope = nullptr;
950 if (MDNode *IA = DV.getInlinedAt()) {
951 DebugLoc DL = DebugLoc::getFromDILocation(IA);
952 Scope = LScopes.findInlinedScope(DebugLoc::get(
953 DL.getLine(), DL.getCol(), DV.getContext(), IA));
955 Scope = LScopes.findLexicalScope(DV.getContext());
956 // If variable scope is not found then skip this variable.
960 Processed.insert(DV);
961 const MachineInstr *MInsn = Ranges.front().first;
962 assert(MInsn->isDebugValue() && "History must begin with debug value");
963 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
964 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
965 DbgVariable *RegVar = ConcreteVariables.back().get();
966 InfoHolder.addScopeVariable(Scope, RegVar);
968 // Check if the first DBG_VALUE is valid for the rest of the function.
969 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
972 // Handle multiple DBG_VALUE instructions describing one variable.
973 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
975 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
976 DebugLocList &LocList = DotDebugLocEntries.back();
979 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
981 // Build the location list for this variable.
982 buildLocationList(LocList.List, Ranges);
985 // Collect info for variables that were optimized out.
986 DIArray Variables = SP.getVariables();
987 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
988 DIVariable DV(Variables.getElement(i));
989 assert(DV.isVariable());
990 if (!Processed.insert(DV))
992 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
993 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
995 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
996 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1001 // Return Label preceding the instruction.
1002 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1003 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1004 assert(Label && "Didn't insert label before instruction");
1008 // Return Label immediately following the instruction.
1009 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1010 return LabelsAfterInsn.lookup(MI);
1013 // Process beginning of an instruction.
1014 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1015 assert(CurMI == nullptr);
1017 // Check if source location changes, but ignore DBG_VALUE locations.
1018 if (!MI->isDebugValue()) {
1019 DebugLoc DL = MI->getDebugLoc();
1020 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1023 if (DL == PrologEndLoc) {
1024 Flags |= DWARF2_FLAG_PROLOGUE_END;
1025 PrologEndLoc = DebugLoc();
1027 if (PrologEndLoc.isUnknown())
1028 Flags |= DWARF2_FLAG_IS_STMT;
1030 if (!DL.isUnknown()) {
1031 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1032 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1034 recordSourceLine(0, 0, nullptr, 0);
1038 // Insert labels where requested.
1039 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1040 LabelsBeforeInsn.find(MI);
1043 if (I == LabelsBeforeInsn.end())
1046 // Label already assigned.
1051 PrevLabel = MMI->getContext().CreateTempSymbol();
1052 Asm->OutStreamer.EmitLabel(PrevLabel);
1054 I->second = PrevLabel;
1057 // Process end of an instruction.
1058 void DwarfDebug::endInstruction() {
1059 assert(CurMI != nullptr);
1060 // Don't create a new label after DBG_VALUE instructions.
1061 // They don't generate code.
1062 if (!CurMI->isDebugValue())
1063 PrevLabel = nullptr;
1065 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1066 LabelsAfterInsn.find(CurMI);
1070 if (I == LabelsAfterInsn.end())
1073 // Label already assigned.
1077 // We need a label after this instruction.
1079 PrevLabel = MMI->getContext().CreateTempSymbol();
1080 Asm->OutStreamer.EmitLabel(PrevLabel);
1082 I->second = PrevLabel;
1085 // Each LexicalScope has first instruction and last instruction to mark
1086 // beginning and end of a scope respectively. Create an inverse map that list
1087 // scopes starts (and ends) with an instruction. One instruction may start (or
1088 // end) multiple scopes. Ignore scopes that are not reachable.
1089 void DwarfDebug::identifyScopeMarkers() {
1090 SmallVector<LexicalScope *, 4> WorkList;
1091 WorkList.push_back(LScopes.getCurrentFunctionScope());
1092 while (!WorkList.empty()) {
1093 LexicalScope *S = WorkList.pop_back_val();
1095 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1096 if (!Children.empty())
1097 WorkList.append(Children.begin(), Children.end());
1099 if (S->isAbstractScope())
1102 for (const InsnRange &R : S->getRanges()) {
1103 assert(R.first && "InsnRange does not have first instruction!");
1104 assert(R.second && "InsnRange does not have second instruction!");
1105 requestLabelBeforeInsn(R.first);
1106 requestLabelAfterInsn(R.second);
1111 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1112 // First known non-DBG_VALUE and non-frame setup location marks
1113 // the beginning of the function body.
1114 for (const auto &MBB : *MF)
1115 for (const auto &MI : MBB)
1116 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1117 !MI.getDebugLoc().isUnknown())
1118 return MI.getDebugLoc();
1122 // Gather pre-function debug information. Assumes being called immediately
1123 // after the function entry point has been emitted.
1124 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1127 // If there's no debug info for the function we're not going to do anything.
1128 if (!MMI->hasDebugInfo())
1131 auto DI = FunctionDIs.find(MF->getFunction());
1132 if (DI == FunctionDIs.end())
1135 // Grab the lexical scopes for the function, if we don't have any of those
1136 // then we're not going to be able to do anything.
1137 LScopes.initialize(*MF);
1138 if (LScopes.empty())
1141 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1143 // Make sure that each lexical scope will have a begin/end label.
1144 identifyScopeMarkers();
1146 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1147 // belongs to so that we add to the correct per-cu line table in the
1149 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1150 // FnScope->getScopeNode() and DI->second should represent the same function,
1151 // though they may not be the same MDNode due to inline functions merged in
1152 // LTO where the debug info metadata still differs (either due to distinct
1153 // written differences - two versions of a linkonce_odr function
1154 // written/copied into two separate files, or some sub-optimal metadata that
1155 // isn't structurally identical (see: file path/name info from clang, which
1156 // includes the directory of the cpp file being built, even when the file name
1157 // is absolute (such as an <> lookup header)))
1158 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1159 assert(TheCU && "Unable to find compile unit!");
1160 if (Asm->OutStreamer.hasRawTextSupport())
1161 // Use a single line table if we are generating assembly.
1162 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1164 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1166 // Emit a label for the function so that we have a beginning address.
1167 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1168 // Assumes in correct section after the entry point.
1169 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1171 // Calculate history for local variables.
1172 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1175 // Request labels for the full history.
1176 for (const auto &I : DbgValues) {
1177 const auto &Ranges = I.second;
1181 // The first mention of a function argument gets the FunctionBeginSym
1182 // label, so arguments are visible when breaking at function entry.
1183 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1184 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1185 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1186 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1187 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1188 // Mark all non-overlapping initial pieces.
1189 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1190 DIExpression Piece = I->first->getDebugExpression();
1191 if (std::all_of(Ranges.begin(), I,
1192 [&](DbgValueHistoryMap::InstrRange Pred) {
1193 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1195 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1202 for (const auto &Range : Ranges) {
1203 requestLabelBeforeInsn(Range.first);
1205 requestLabelAfterInsn(Range.second);
1209 PrevInstLoc = DebugLoc();
1210 PrevLabel = FunctionBeginSym;
1212 // Record beginning of function.
1213 PrologEndLoc = findPrologueEndLoc(MF);
1214 if (!PrologEndLoc.isUnknown()) {
1215 DebugLoc FnStartDL =
1216 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1218 FnStartDL.getLine(), FnStartDL.getCol(),
1219 FnStartDL.getScope(MF->getFunction()->getContext()),
1220 // We'd like to list the prologue as "not statements" but GDB behaves
1221 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1222 DWARF2_FLAG_IS_STMT);
1226 // Gather and emit post-function debug information.
1227 void DwarfDebug::endFunction(const MachineFunction *MF) {
1228 assert(CurFn == MF &&
1229 "endFunction should be called with the same function as beginFunction");
1231 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1232 !FunctionDIs.count(MF->getFunction())) {
1233 // If we don't have a lexical scope for this function then there will
1234 // be a hole in the range information. Keep note of this by setting the
1235 // previously used section to nullptr.
1241 // Define end label for subprogram.
1242 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1243 // Assumes in correct section after the entry point.
1244 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1246 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1247 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1249 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1250 DISubprogram SP(FnScope->getScopeNode());
1251 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1253 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1254 collectVariableInfo(TheCU, SP, ProcessedVars);
1256 // Add the range of this function to the list of ranges for the CU.
1257 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1259 // Under -gmlt, skip building the subprogram if there are no inlined
1260 // subroutines inside it.
1261 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1262 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1263 assert(InfoHolder.getScopeVariables().empty());
1264 assert(DbgValues.empty());
1265 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1266 // by a -gmlt CU. Add a test and remove this assertion.
1267 assert(AbstractVariables.empty());
1268 LabelsBeforeInsn.clear();
1269 LabelsAfterInsn.clear();
1270 PrevLabel = nullptr;
1276 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1278 // Construct abstract scopes.
1279 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1280 DISubprogram SP(AScope->getScopeNode());
1281 assert(SP.isSubprogram());
1282 // Collect info for variables that were optimized out.
1283 DIArray Variables = SP.getVariables();
1284 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1285 DIVariable DV(Variables.getElement(i));
1286 assert(DV && DV.isVariable());
1287 if (!ProcessedVars.insert(DV))
1289 ensureAbstractVariableIsCreated(DV, DV.getContext());
1290 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1291 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1293 constructAbstractSubprogramScopeDIE(AScope);
1296 TheCU.constructSubprogramScopeDIE(FnScope);
1299 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1300 // DbgVariables except those that are also in AbstractVariables (since they
1301 // can be used cross-function)
1302 InfoHolder.getScopeVariables().clear();
1304 LabelsBeforeInsn.clear();
1305 LabelsAfterInsn.clear();
1306 PrevLabel = nullptr;
1310 // Register a source line with debug info. Returns the unique label that was
1311 // emitted and which provides correspondence to the source line list.
1312 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1317 unsigned Discriminator = 0;
1318 if (DIScope Scope = DIScope(S)) {
1319 assert(Scope.isScope());
1320 Fn = Scope.getFilename();
1321 Dir = Scope.getDirectory();
1322 if (Scope.isLexicalBlockFile())
1323 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1325 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1326 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1327 .getOrCreateSourceID(Fn, Dir);
1329 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1333 //===----------------------------------------------------------------------===//
1335 //===----------------------------------------------------------------------===//
1337 // Emit initial Dwarf sections with a label at the start of each one.
1338 void DwarfDebug::emitSectionLabels() {
1339 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1341 // Dwarf sections base addresses.
1342 DwarfInfoSectionSym =
1343 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1344 if (useSplitDwarf()) {
1345 DwarfInfoDWOSectionSym =
1346 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1347 DwarfTypesDWOSectionSym =
1348 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1350 DwarfAbbrevSectionSym =
1351 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1352 if (useSplitDwarf())
1353 DwarfAbbrevDWOSectionSym = emitSectionSym(
1354 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1355 if (GenerateARangeSection)
1356 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1358 DwarfLineSectionSym =
1359 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1360 if (GenerateGnuPubSections) {
1361 DwarfGnuPubNamesSectionSym =
1362 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1363 DwarfGnuPubTypesSectionSym =
1364 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1365 } else if (HasDwarfPubSections) {
1366 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1367 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1370 DwarfStrSectionSym =
1371 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1372 if (useSplitDwarf()) {
1373 DwarfStrDWOSectionSym =
1374 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1375 DwarfAddrSectionSym =
1376 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1377 DwarfDebugLocSectionSym =
1378 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1380 DwarfDebugLocSectionSym =
1381 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1382 DwarfDebugRangeSectionSym =
1383 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1386 // Recursively emits a debug information entry.
1387 void DwarfDebug::emitDIE(DIE &Die) {
1388 // Get the abbreviation for this DIE.
1389 const DIEAbbrev &Abbrev = Die.getAbbrev();
1391 // Emit the code (index) for the abbreviation.
1392 if (Asm->isVerbose())
1393 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1394 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1395 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1396 dwarf::TagString(Abbrev.getTag()));
1397 Asm->EmitULEB128(Abbrev.getNumber());
1399 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1400 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1402 // Emit the DIE attribute values.
1403 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1404 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1405 dwarf::Form Form = AbbrevData[i].getForm();
1406 assert(Form && "Too many attributes for DIE (check abbreviation)");
1408 if (Asm->isVerbose()) {
1409 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1410 if (Attr == dwarf::DW_AT_accessibility)
1411 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1412 cast<DIEInteger>(Values[i])->getValue()));
1415 // Emit an attribute using the defined form.
1416 Values[i]->EmitValue(Asm, Form);
1419 // Emit the DIE children if any.
1420 if (Abbrev.hasChildren()) {
1421 for (auto &Child : Die.getChildren())
1424 Asm->OutStreamer.AddComment("End Of Children Mark");
1429 // Emit the debug info section.
1430 void DwarfDebug::emitDebugInfo() {
1431 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1433 Holder.emitUnits(DwarfAbbrevSectionSym);
1436 // Emit the abbreviation section.
1437 void DwarfDebug::emitAbbreviations() {
1438 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1440 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1443 // Emit the last address of the section and the end of the line matrix.
1444 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1445 // Define last address of section.
1446 Asm->OutStreamer.AddComment("Extended Op");
1449 Asm->OutStreamer.AddComment("Op size");
1450 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1451 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1452 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1454 Asm->OutStreamer.AddComment("Section end label");
1456 Asm->OutStreamer.EmitSymbolValue(
1457 Asm->GetTempSymbol("section_end", SectionEnd),
1458 Asm->getDataLayout().getPointerSize());
1460 // Mark end of matrix.
1461 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1467 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1468 StringRef TableName, StringRef SymName) {
1469 Accel.FinalizeTable(Asm, TableName);
1470 Asm->OutStreamer.SwitchSection(Section);
1471 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1472 Asm->OutStreamer.EmitLabel(SectionBegin);
1474 // Emit the full data.
1475 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1478 // Emit visible names into a hashed accelerator table section.
1479 void DwarfDebug::emitAccelNames() {
1480 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1481 "Names", "names_begin");
1484 // Emit objective C classes and categories into a hashed accelerator table
1486 void DwarfDebug::emitAccelObjC() {
1487 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1488 "ObjC", "objc_begin");
1491 // Emit namespace dies into a hashed accelerator table.
1492 void DwarfDebug::emitAccelNamespaces() {
1493 emitAccel(AccelNamespace,
1494 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1495 "namespac", "namespac_begin");
1498 // Emit type dies into a hashed accelerator table.
1499 void DwarfDebug::emitAccelTypes() {
1500 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1501 "types", "types_begin");
1504 // Public name handling.
1505 // The format for the various pubnames:
1507 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1508 // for the DIE that is named.
1510 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1511 // into the CU and the index value is computed according to the type of value
1512 // for the DIE that is named.
1514 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1515 // it's the offset within the debug_info/debug_types dwo section, however, the
1516 // reference in the pubname header doesn't change.
1518 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1519 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1521 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1523 // We could have a specification DIE that has our most of our knowledge,
1524 // look for that now.
1525 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1527 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1528 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1529 Linkage = dwarf::GIEL_EXTERNAL;
1530 } else if (Die->findAttribute(dwarf::DW_AT_external))
1531 Linkage = dwarf::GIEL_EXTERNAL;
1533 switch (Die->getTag()) {
1534 case dwarf::DW_TAG_class_type:
1535 case dwarf::DW_TAG_structure_type:
1536 case dwarf::DW_TAG_union_type:
1537 case dwarf::DW_TAG_enumeration_type:
1538 return dwarf::PubIndexEntryDescriptor(
1539 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1540 ? dwarf::GIEL_STATIC
1541 : dwarf::GIEL_EXTERNAL);
1542 case dwarf::DW_TAG_typedef:
1543 case dwarf::DW_TAG_base_type:
1544 case dwarf::DW_TAG_subrange_type:
1545 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1546 case dwarf::DW_TAG_namespace:
1547 return dwarf::GIEK_TYPE;
1548 case dwarf::DW_TAG_subprogram:
1549 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1550 case dwarf::DW_TAG_constant:
1551 case dwarf::DW_TAG_variable:
1552 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1553 case dwarf::DW_TAG_enumerator:
1554 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1555 dwarf::GIEL_STATIC);
1557 return dwarf::GIEK_NONE;
1561 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1563 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1564 const MCSection *PSec =
1565 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1566 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1568 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1571 void DwarfDebug::emitDebugPubSection(
1572 bool GnuStyle, const MCSection *PSec, StringRef Name,
1573 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1574 for (const auto &NU : CUMap) {
1575 DwarfCompileUnit *TheU = NU.second;
1577 const auto &Globals = (TheU->*Accessor)();
1579 if (Globals.empty())
1582 if (auto Skeleton = TheU->getSkeleton())
1584 unsigned ID = TheU->getUniqueID();
1586 // Start the dwarf pubnames section.
1587 Asm->OutStreamer.SwitchSection(PSec);
1590 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1591 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1592 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1593 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1595 Asm->OutStreamer.EmitLabel(BeginLabel);
1597 Asm->OutStreamer.AddComment("DWARF Version");
1598 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1600 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1601 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1603 Asm->OutStreamer.AddComment("Compilation Unit Length");
1604 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1606 // Emit the pubnames for this compilation unit.
1607 for (const auto &GI : Globals) {
1608 const char *Name = GI.getKeyData();
1609 const DIE *Entity = GI.second;
1611 Asm->OutStreamer.AddComment("DIE offset");
1612 Asm->EmitInt32(Entity->getOffset());
1615 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1616 Asm->OutStreamer.AddComment(
1617 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1618 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1619 Asm->EmitInt8(Desc.toBits());
1622 Asm->OutStreamer.AddComment("External Name");
1623 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1626 Asm->OutStreamer.AddComment("End Mark");
1628 Asm->OutStreamer.EmitLabel(EndLabel);
1632 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1633 const MCSection *PSec =
1634 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1635 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1637 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1640 // Emit visible names into a debug str section.
1641 void DwarfDebug::emitDebugStr() {
1642 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1643 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1646 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1647 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1648 const DITypeIdentifierMap &Map,
1649 ArrayRef<DebugLocEntry::Value> Values) {
1650 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1651 return P.isVariablePiece();
1652 }) && "all values are expected to be pieces");
1653 assert(std::is_sorted(Values.begin(), Values.end()) &&
1654 "pieces are expected to be sorted");
1656 unsigned Offset = 0;
1657 for (auto Piece : Values) {
1658 DIExpression Expr = Piece.getExpression();
1659 unsigned PieceOffset = Expr.getPieceOffset();
1660 unsigned PieceSize = Expr.getPieceSize();
1661 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1662 if (Offset < PieceOffset) {
1663 // The DWARF spec seriously mandates pieces with no locations for gaps.
1664 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1665 Offset += PieceOffset-Offset;
1668 Offset += PieceSize;
1670 const unsigned SizeOfByte = 8;
1672 DIVariable Var = Piece.getVariable();
1673 assert(!Var.isIndirect() && "indirect address for piece");
1674 unsigned VarSize = Var.getSizeInBits(Map);
1675 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1676 && "piece is larger than or outside of variable");
1677 assert(PieceSize*SizeOfByte != VarSize
1678 && "piece covers entire variable");
1680 if (Piece.isLocation() && Piece.getLoc().isReg())
1681 Asm->EmitDwarfRegOpPiece(Streamer,
1683 PieceSize*SizeOfByte);
1685 emitDebugLocValue(Streamer, Piece);
1686 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1692 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1693 const DebugLocEntry &Entry) {
1694 const DebugLocEntry::Value Value = Entry.getValues()[0];
1695 if (Value.isVariablePiece())
1696 // Emit all pieces that belong to the same variable and range.
1697 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1699 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1700 emitDebugLocValue(Streamer, Value);
1703 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1704 const DebugLocEntry::Value &Value) {
1705 DIVariable DV = Value.getVariable();
1707 if (Value.isInt()) {
1708 DIBasicType BTy(resolve(DV.getType()));
1709 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1710 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1711 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1712 Streamer.EmitSLEB128(Value.getInt());
1714 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1715 Streamer.EmitULEB128(Value.getInt());
1717 } else if (Value.isLocation()) {
1718 MachineLocation Loc = Value.getLoc();
1719 DIExpression Expr = Value.getExpression();
1722 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1724 // Complex address entry.
1725 unsigned N = Expr.getNumElements();
1727 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1728 if (Loc.getOffset()) {
1730 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1731 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1732 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1733 Streamer.EmitSLEB128(Expr.getElement(1));
1735 // If first address element is OpPlus then emit
1736 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1737 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1738 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1742 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1745 // Emit remaining complex address elements.
1746 for (; i < N; ++i) {
1747 uint64_t Element = Expr.getElement(i);
1748 if (Element == dwarf::DW_OP_plus) {
1749 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1750 Streamer.EmitULEB128(Expr.getElement(++i));
1751 } else if (Element == dwarf::DW_OP_deref) {
1753 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1754 } else if (Element == dwarf::DW_OP_piece) {
1756 // handled in emitDebugLocEntry.
1758 llvm_unreachable("unknown Opcode found in complex address");
1762 // else ... ignore constant fp. There is not any good way to
1763 // to represent them here in dwarf.
1767 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1768 Asm->OutStreamer.AddComment("Loc expr size");
1769 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1770 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1771 Asm->EmitLabelDifference(end, begin, 2);
1772 Asm->OutStreamer.EmitLabel(begin);
1774 APByteStreamer Streamer(*Asm);
1775 emitDebugLocEntry(Streamer, Entry);
1777 Asm->OutStreamer.EmitLabel(end);
1780 // Emit locations into the debug loc section.
1781 void DwarfDebug::emitDebugLoc() {
1782 // Start the dwarf loc section.
1783 Asm->OutStreamer.SwitchSection(
1784 Asm->getObjFileLowering().getDwarfLocSection());
1785 unsigned char Size = Asm->getDataLayout().getPointerSize();
1786 for (const auto &DebugLoc : DotDebugLocEntries) {
1787 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1788 const DwarfCompileUnit *CU = DebugLoc.CU;
1789 assert(!CU->getRanges().empty());
1790 for (const auto &Entry : DebugLoc.List) {
1791 // Set up the range. This range is relative to the entry point of the
1792 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1793 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1794 if (CU->getRanges().size() == 1) {
1795 // Grab the begin symbol from the first range as our base.
1796 const MCSymbol *Base = CU->getRanges()[0].getStart();
1797 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1798 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1800 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1801 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1804 emitDebugLocEntryLocation(Entry);
1806 Asm->OutStreamer.EmitIntValue(0, Size);
1807 Asm->OutStreamer.EmitIntValue(0, Size);
1811 void DwarfDebug::emitDebugLocDWO() {
1812 Asm->OutStreamer.SwitchSection(
1813 Asm->getObjFileLowering().getDwarfLocDWOSection());
1814 for (const auto &DebugLoc : DotDebugLocEntries) {
1815 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1816 for (const auto &Entry : DebugLoc.List) {
1817 // Just always use start_length for now - at least that's one address
1818 // rather than two. We could get fancier and try to, say, reuse an
1819 // address we know we've emitted elsewhere (the start of the function?
1820 // The start of the CU or CU subrange that encloses this range?)
1821 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1822 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1823 Asm->EmitULEB128(idx);
1824 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1826 emitDebugLocEntryLocation(Entry);
1828 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1833 const MCSymbol *Start, *End;
1836 // Emit a debug aranges section, containing a CU lookup for any
1837 // address we can tie back to a CU.
1838 void DwarfDebug::emitDebugARanges() {
1839 // Start the dwarf aranges section.
1840 Asm->OutStreamer.SwitchSection(
1841 Asm->getObjFileLowering().getDwarfARangesSection());
1843 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1847 // Build a list of sections used.
1848 std::vector<const MCSection *> Sections;
1849 for (const auto &it : SectionMap) {
1850 const MCSection *Section = it.first;
1851 Sections.push_back(Section);
1854 // Sort the sections into order.
1855 // This is only done to ensure consistent output order across different runs.
1856 std::sort(Sections.begin(), Sections.end(), SectionSort);
1858 // Build a set of address spans, sorted by CU.
1859 for (const MCSection *Section : Sections) {
1860 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1861 if (List.size() < 2)
1864 // Sort the symbols by offset within the section.
1865 std::sort(List.begin(), List.end(),
1866 [&](const SymbolCU &A, const SymbolCU &B) {
1867 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1868 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1870 // Symbols with no order assigned should be placed at the end.
1871 // (e.g. section end labels)
1879 // If we have no section (e.g. common), just write out
1880 // individual spans for each symbol.
1882 for (const SymbolCU &Cur : List) {
1884 Span.Start = Cur.Sym;
1887 Spans[Cur.CU].push_back(Span);
1890 // Build spans between each label.
1891 const MCSymbol *StartSym = List[0].Sym;
1892 for (size_t n = 1, e = List.size(); n < e; n++) {
1893 const SymbolCU &Prev = List[n - 1];
1894 const SymbolCU &Cur = List[n];
1896 // Try and build the longest span we can within the same CU.
1897 if (Cur.CU != Prev.CU) {
1899 Span.Start = StartSym;
1901 Spans[Prev.CU].push_back(Span);
1908 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1910 // Build a list of CUs used.
1911 std::vector<DwarfCompileUnit *> CUs;
1912 for (const auto &it : Spans) {
1913 DwarfCompileUnit *CU = it.first;
1917 // Sort the CU list (again, to ensure consistent output order).
1918 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1919 return A->getUniqueID() < B->getUniqueID();
1922 // Emit an arange table for each CU we used.
1923 for (DwarfCompileUnit *CU : CUs) {
1924 std::vector<ArangeSpan> &List = Spans[CU];
1926 // Emit size of content not including length itself.
1927 unsigned ContentSize =
1928 sizeof(int16_t) + // DWARF ARange version number
1929 sizeof(int32_t) + // Offset of CU in the .debug_info section
1930 sizeof(int8_t) + // Pointer Size (in bytes)
1931 sizeof(int8_t); // Segment Size (in bytes)
1933 unsigned TupleSize = PtrSize * 2;
1935 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1937 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1939 ContentSize += Padding;
1940 ContentSize += (List.size() + 1) * TupleSize;
1942 // For each compile unit, write the list of spans it covers.
1943 Asm->OutStreamer.AddComment("Length of ARange Set");
1944 Asm->EmitInt32(ContentSize);
1945 Asm->OutStreamer.AddComment("DWARF Arange version number");
1946 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1947 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1948 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1949 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1950 Asm->EmitInt8(PtrSize);
1951 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1954 Asm->OutStreamer.EmitFill(Padding, 0xff);
1956 for (const ArangeSpan &Span : List) {
1957 Asm->EmitLabelReference(Span.Start, PtrSize);
1959 // Calculate the size as being from the span start to it's end.
1961 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1963 // For symbols without an end marker (e.g. common), we
1964 // write a single arange entry containing just that one symbol.
1965 uint64_t Size = SymSize[Span.Start];
1969 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1973 Asm->OutStreamer.AddComment("ARange terminator");
1974 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1975 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1979 // Emit visible names into a debug ranges section.
1980 void DwarfDebug::emitDebugRanges() {
1981 // Start the dwarf ranges section.
1982 Asm->OutStreamer.SwitchSection(
1983 Asm->getObjFileLowering().getDwarfRangesSection());
1985 // Size for our labels.
1986 unsigned char Size = Asm->getDataLayout().getPointerSize();
1988 // Grab the specific ranges for the compile units in the module.
1989 for (const auto &I : CUMap) {
1990 DwarfCompileUnit *TheCU = I.second;
1992 // Iterate over the misc ranges for the compile units in the module.
1993 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1994 // Emit our symbol so we can find the beginning of the range.
1995 Asm->OutStreamer.EmitLabel(List.getSym());
1997 for (const RangeSpan &Range : List.getRanges()) {
1998 const MCSymbol *Begin = Range.getStart();
1999 const MCSymbol *End = Range.getEnd();
2000 assert(Begin && "Range without a begin symbol?");
2001 assert(End && "Range without an end symbol?");
2002 if (TheCU->getRanges().size() == 1) {
2003 // Grab the begin symbol from the first range as our base.
2004 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2005 Asm->EmitLabelDifference(Begin, Base, Size);
2006 Asm->EmitLabelDifference(End, Base, Size);
2008 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2009 Asm->OutStreamer.EmitSymbolValue(End, Size);
2013 // And terminate the list with two 0 values.
2014 Asm->OutStreamer.EmitIntValue(0, Size);
2015 Asm->OutStreamer.EmitIntValue(0, Size);
2018 // Now emit a range for the CU itself.
2019 if (TheCU->getRanges().size() > 1) {
2020 Asm->OutStreamer.EmitLabel(
2021 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2022 for (const RangeSpan &Range : TheCU->getRanges()) {
2023 const MCSymbol *Begin = Range.getStart();
2024 const MCSymbol *End = Range.getEnd();
2025 assert(Begin && "Range without a begin symbol?");
2026 assert(End && "Range without an end symbol?");
2027 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2028 Asm->OutStreamer.EmitSymbolValue(End, Size);
2030 // And terminate the list with two 0 values.
2031 Asm->OutStreamer.EmitIntValue(0, Size);
2032 Asm->OutStreamer.EmitIntValue(0, Size);
2037 // DWARF5 Experimental Separate Dwarf emitters.
2039 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2040 std::unique_ptr<DwarfUnit> NewU) {
2041 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2042 U.getCUNode().getSplitDebugFilename());
2044 if (!CompilationDir.empty())
2045 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2047 addGnuPubAttributes(*NewU, Die);
2049 SkeletonHolder.addUnit(std::move(NewU));
2052 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2053 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2054 // DW_AT_addr_base, DW_AT_ranges_base.
2055 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2057 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2058 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2059 DwarfCompileUnit &NewCU = *OwnedUnit;
2060 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2061 DwarfInfoSectionSym);
2063 NewCU.initStmtList(DwarfLineSectionSym);
2065 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2070 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2071 // compile units that would normally be in debug_info.
2072 void DwarfDebug::emitDebugInfoDWO() {
2073 assert(useSplitDwarf() && "No split dwarf debug info?");
2074 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2075 // emit relocations into the dwo file.
2076 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2079 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2080 // abbreviations for the .debug_info.dwo section.
2081 void DwarfDebug::emitDebugAbbrevDWO() {
2082 assert(useSplitDwarf() && "No split dwarf?");
2083 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2086 void DwarfDebug::emitDebugLineDWO() {
2087 assert(useSplitDwarf() && "No split dwarf?");
2088 Asm->OutStreamer.SwitchSection(
2089 Asm->getObjFileLowering().getDwarfLineDWOSection());
2090 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2093 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2094 // string section and is identical in format to traditional .debug_str
2096 void DwarfDebug::emitDebugStrDWO() {
2097 assert(useSplitDwarf() && "No split dwarf?");
2098 const MCSection *OffSec =
2099 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2100 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2104 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2105 if (!useSplitDwarf())
2108 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2109 return &SplitTypeUnitFileTable;
2112 static uint64_t makeTypeSignature(StringRef Identifier) {
2114 Hash.update(Identifier);
2115 // ... take the least significant 8 bytes and return those. Our MD5
2116 // implementation always returns its results in little endian, swap bytes
2118 MD5::MD5Result Result;
2120 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2123 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2124 StringRef Identifier, DIE &RefDie,
2125 DICompositeType CTy) {
2126 // Fast path if we're building some type units and one has already used the
2127 // address pool we know we're going to throw away all this work anyway, so
2128 // don't bother building dependent types.
2129 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2132 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2134 CU.addDIETypeSignature(RefDie, *TU);
2138 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2139 AddrPool.resetUsedFlag();
2141 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2142 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2143 this, &InfoHolder, getDwoLineTable(CU));
2144 DwarfTypeUnit &NewTU = *OwnedUnit;
2145 DIE &UnitDie = NewTU.getUnitDie();
2147 TypeUnitsUnderConstruction.push_back(
2148 std::make_pair(std::move(OwnedUnit), CTy));
2150 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2153 uint64_t Signature = makeTypeSignature(Identifier);
2154 NewTU.setTypeSignature(Signature);
2156 if (useSplitDwarf())
2157 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2158 DwarfTypesDWOSectionSym);
2160 CU.applyStmtList(UnitDie);
2162 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2165 NewTU.setType(NewTU.createTypeDIE(CTy));
2168 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2169 TypeUnitsUnderConstruction.clear();
2171 // Types referencing entries in the address table cannot be placed in type
2173 if (AddrPool.hasBeenUsed()) {
2175 // Remove all the types built while building this type.
2176 // This is pessimistic as some of these types might not be dependent on
2177 // the type that used an address.
2178 for (const auto &TU : TypeUnitsToAdd)
2179 DwarfTypeUnits.erase(TU.second);
2181 // Construct this type in the CU directly.
2182 // This is inefficient because all the dependent types will be rebuilt
2183 // from scratch, including building them in type units, discovering that
2184 // they depend on addresses, throwing them out and rebuilding them.
2185 CU.constructTypeDIE(RefDie, CTy);
2189 // If the type wasn't dependent on fission addresses, finish adding the type
2190 // and all its dependent types.
2191 for (auto &TU : TypeUnitsToAdd)
2192 InfoHolder.addUnit(std::move(TU.first));
2194 CU.addDIETypeSignature(RefDie, NewTU);
2197 // Accelerator table mutators - add each name along with its companion
2198 // DIE to the proper table while ensuring that the name that we're going
2199 // to reference is in the string table. We do this since the names we
2200 // add may not only be identical to the names in the DIE.
2201 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2202 if (!useDwarfAccelTables())
2204 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2208 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2209 if (!useDwarfAccelTables())
2211 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2215 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2216 if (!useDwarfAccelTables())
2218 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2222 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2223 if (!useDwarfAccelTables())
2225 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),