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 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
335 if (auto *SkelCU = CU.getSkeleton())
339 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
340 assert(Scope && Scope->getScopeNode());
341 assert(Scope->isAbstractScope());
342 assert(!Scope->getInlinedAt());
344 const MDNode *SP = Scope->getScopeNode();
346 ProcessedSPNodes.insert(SP);
348 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
349 // was inlined from another compile unit.
350 auto &CU = SPMap[SP];
351 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
352 CU.constructAbstractSubprogramScopeDIE(Scope);
356 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
357 if (!GenerateGnuPubSections)
360 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
363 // Create new DwarfCompileUnit for the given metadata node with tag
364 // DW_TAG_compile_unit.
365 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
366 StringRef FN = DIUnit.getFilename();
367 CompilationDir = DIUnit.getDirectory();
369 auto OwnedUnit = make_unique<DwarfCompileUnit>(
370 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
371 DwarfCompileUnit &NewCU = *OwnedUnit;
372 DIE &Die = NewCU.getUnitDie();
373 InfoHolder.addUnit(std::move(OwnedUnit));
375 NewCU.setSkeleton(constructSkeletonCU(NewCU));
377 // LTO with assembly output shares a single line table amongst multiple CUs.
378 // To avoid the compilation directory being ambiguous, let the line table
379 // explicitly describe the directory of all files, never relying on the
380 // compilation directory.
381 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
382 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
383 NewCU.getUniqueID(), CompilationDir);
385 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
386 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
387 DIUnit.getLanguage());
388 NewCU.addString(Die, dwarf::DW_AT_name, FN);
390 if (!useSplitDwarf()) {
391 NewCU.initStmtList(DwarfLineSectionSym);
393 // If we're using split dwarf the compilation dir is going to be in the
394 // skeleton CU and so we don't need to duplicate it here.
395 if (!CompilationDir.empty())
396 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
398 addGnuPubAttributes(NewCU, Die);
401 if (DIUnit.isOptimized())
402 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
404 StringRef Flags = DIUnit.getFlags();
406 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
408 if (unsigned RVer = DIUnit.getRunTimeVersion())
409 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
410 dwarf::DW_FORM_data1, RVer);
413 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
414 DwarfInfoDWOSectionSym);
416 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
417 DwarfInfoSectionSym);
419 CUMap.insert(std::make_pair(DIUnit, &NewCU));
420 CUDieMap.insert(std::make_pair(&Die, &NewCU));
424 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
426 DIImportedEntity Module(N);
427 assert(Module.Verify());
428 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
429 D->addChild(TheCU.constructImportedEntityDIE(Module));
432 // Emit all Dwarf sections that should come prior to the content. Create
433 // global DIEs and emit initial debug info sections. This is invoked by
434 // the target AsmPrinter.
435 void DwarfDebug::beginModule() {
436 if (DisableDebugInfoPrinting)
439 const Module *M = MMI->getModule();
441 FunctionDIs = makeSubprogramMap(*M);
443 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
446 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
448 // Emit initial sections so we can reference labels later.
451 SingleCU = CU_Nodes->getNumOperands() == 1;
453 for (MDNode *N : CU_Nodes->operands()) {
454 DICompileUnit CUNode(N);
455 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
456 DIArray ImportedEntities = CUNode.getImportedEntities();
457 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
458 ScopesWithImportedEntities.push_back(std::make_pair(
459 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
460 ImportedEntities.getElement(i)));
461 std::sort(ScopesWithImportedEntities.begin(),
462 ScopesWithImportedEntities.end(), less_first());
463 DIArray GVs = CUNode.getGlobalVariables();
464 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
465 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
466 DIArray SPs = CUNode.getSubprograms();
467 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
468 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
469 DIArray EnumTypes = CUNode.getEnumTypes();
470 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
471 DIType Ty(EnumTypes.getElement(i));
472 // The enum types array by design contains pointers to
473 // MDNodes rather than DIRefs. Unique them here.
474 DIType UniqueTy(resolve(Ty.getRef()));
475 CU.getOrCreateTypeDIE(UniqueTy);
477 DIArray RetainedTypes = CUNode.getRetainedTypes();
478 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
479 DIType Ty(RetainedTypes.getElement(i));
480 // The retained types array by design contains pointers to
481 // MDNodes rather than DIRefs. Unique them here.
482 DIType UniqueTy(resolve(Ty.getRef()));
483 CU.getOrCreateTypeDIE(UniqueTy);
485 // Emit imported_modules last so that the relevant context is already
487 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
488 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
491 // Tell MMI that we have debug info.
492 MMI->setDebugInfoAvailability(true);
494 // Prime section data.
495 SectionMap[Asm->getObjFileLowering().getTextSection()];
498 void DwarfDebug::finishVariableDefinitions() {
499 for (const auto &Var : ConcreteVariables) {
500 DIE *VariableDie = Var->getDIE();
502 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
503 // in the ConcreteVariables list, rather than looking it up again here.
504 // DIE::getUnit isn't simple - it walks parent pointers, etc.
505 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
507 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
508 if (AbsVar && AbsVar->getDIE()) {
509 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
512 Unit->applyVariableAttributes(*Var, *VariableDie);
516 void DwarfDebug::finishSubprogramDefinitions() {
517 for (const auto &P : SPMap)
518 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
519 CU.finishSubprogramDefinition(DISubprogram(P.first));
524 // Collect info for variables that were optimized out.
525 void DwarfDebug::collectDeadVariables() {
526 const Module *M = MMI->getModule();
528 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
529 for (MDNode *N : CU_Nodes->operands()) {
530 DICompileUnit TheCU(N);
531 // Construct subprogram DIE and add variables DIEs.
532 DwarfCompileUnit *SPCU =
533 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
534 assert(SPCU && "Unable to find Compile Unit!");
535 DIArray Subprograms = TheCU.getSubprograms();
536 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
537 DISubprogram SP(Subprograms.getElement(i));
538 if (ProcessedSPNodes.count(SP) != 0)
540 SPCU->collectDeadVariables(SP);
546 void DwarfDebug::finalizeModuleInfo() {
547 finishSubprogramDefinitions();
549 finishVariableDefinitions();
551 // Collect info for variables that were optimized out.
552 collectDeadVariables();
554 // Handle anything that needs to be done on a per-unit basis after
555 // all other generation.
556 for (const auto &P : CUMap) {
557 auto &TheCU = *P.second;
558 // Emit DW_AT_containing_type attribute to connect types with their
559 // vtable holding type.
560 TheCU.constructContainingTypeDIEs();
562 // Add CU specific attributes if we need to add any.
563 // If we're splitting the dwarf out now that we've got the entire
564 // CU then add the dwo id to it.
565 auto *SkCU = TheCU.getSkeleton();
566 if (useSplitDwarf()) {
567 // Emit a unique identifier for this CU.
568 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
569 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
570 dwarf::DW_FORM_data8, ID);
571 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
572 dwarf::DW_FORM_data8, ID);
574 // We don't keep track of which addresses are used in which CU so this
575 // is a bit pessimistic under LTO.
576 if (!AddrPool.isEmpty())
577 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
578 DwarfAddrSectionSym, DwarfAddrSectionSym);
579 if (!SkCU->getRangeLists().empty())
580 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
581 DwarfDebugRangeSectionSym,
582 DwarfDebugRangeSectionSym);
585 // If we have code split among multiple sections or non-contiguous
586 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
587 // remain in the .o file, otherwise add a DW_AT_low_pc.
588 // FIXME: We should use ranges allow reordering of code ala
589 // .subsections_via_symbols in mach-o. This would mean turning on
590 // ranges for all subprogram DIEs for mach-o.
591 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
592 if (unsigned NumRanges = TheCU.getRanges().size()) {
594 // A DW_AT_low_pc attribute may also be specified in combination with
595 // DW_AT_ranges to specify the default base address for use in
596 // location lists (see Section 2.6.2) and range lists (see Section
598 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
600 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
601 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
605 // Compute DIE offsets and sizes.
606 InfoHolder.computeSizeAndOffsets();
608 SkeletonHolder.computeSizeAndOffsets();
611 void DwarfDebug::endSections() {
612 // Filter labels by section.
613 for (const SymbolCU &SCU : ArangeLabels) {
614 if (SCU.Sym->isInSection()) {
615 // Make a note of this symbol and it's section.
616 const MCSection *Section = &SCU.Sym->getSection();
617 if (!Section->getKind().isMetadata())
618 SectionMap[Section].push_back(SCU);
620 // Some symbols (e.g. common/bss on mach-o) can have no section but still
621 // appear in the output. This sucks as we rely on sections to build
622 // arange spans. We can do it without, but it's icky.
623 SectionMap[nullptr].push_back(SCU);
627 // Build a list of sections used.
628 std::vector<const MCSection *> Sections;
629 for (const auto &it : SectionMap) {
630 const MCSection *Section = it.first;
631 Sections.push_back(Section);
634 // Sort the sections into order.
635 // This is only done to ensure consistent output order across different runs.
636 std::sort(Sections.begin(), Sections.end(), SectionSort);
638 // Add terminating symbols for each section.
639 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
640 const MCSection *Section = Sections[ID];
641 MCSymbol *Sym = nullptr;
644 // We can't call MCSection::getLabelEndName, as it's only safe to do so
645 // if we know the section name up-front. For user-created sections, the
646 // resulting label may not be valid to use as a label. (section names can
647 // use a greater set of characters on some systems)
648 Sym = Asm->GetTempSymbol("debug_end", ID);
649 Asm->OutStreamer.SwitchSection(Section);
650 Asm->OutStreamer.EmitLabel(Sym);
653 // Insert a final terminator.
654 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
658 // Emit all Dwarf sections that should come after the content.
659 void DwarfDebug::endModule() {
660 assert(CurFn == nullptr);
661 assert(CurMI == nullptr);
663 // If we aren't actually generating debug info (check beginModule -
664 // conditionalized on !DisableDebugInfoPrinting and the presence of the
665 // llvm.dbg.cu metadata node)
666 if (!DwarfInfoSectionSym)
669 // End any existing sections.
670 // TODO: Does this need to happen?
673 // Finalize the debug info for the module.
674 finalizeModuleInfo();
678 // Emit all the DIEs into a debug info section.
681 // Corresponding abbreviations into a abbrev section.
684 // Emit info into a debug aranges section.
685 if (GenerateARangeSection)
688 // Emit info into a debug ranges section.
691 if (useSplitDwarf()) {
694 emitDebugAbbrevDWO();
697 // Emit DWO addresses.
698 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
700 // Emit info into a debug loc section.
703 // Emit info into the dwarf accelerator table sections.
704 if (useDwarfAccelTables()) {
707 emitAccelNamespaces();
711 // Emit the pubnames and pubtypes sections if requested.
712 if (HasDwarfPubSections) {
713 emitDebugPubNames(GenerateGnuPubSections);
714 emitDebugPubTypes(GenerateGnuPubSections);
719 AbstractVariables.clear();
722 // Find abstract variable, if any, associated with Var.
723 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
724 DIVariable &Cleansed) {
725 LLVMContext &Ctx = DV->getContext();
726 // More then one inlined variable corresponds to one abstract variable.
727 // FIXME: This duplication of variables when inlining should probably be
728 // removed. It's done to allow each DIVariable to describe its location
729 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
730 // make it accurate then remove this duplication/cleansing stuff.
731 Cleansed = cleanseInlinedVariable(DV, Ctx);
732 auto I = AbstractVariables.find(Cleansed);
733 if (I != AbstractVariables.end())
734 return I->second.get();
738 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
740 return getExistingAbstractVariable(DV, Cleansed);
743 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
744 LexicalScope *Scope) {
745 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
746 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
747 AbstractVariables[Var] = std::move(AbsDbgVariable);
750 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
751 const MDNode *ScopeNode) {
752 DIVariable Cleansed = DV;
753 if (getExistingAbstractVariable(DV, Cleansed))
756 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
760 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
761 const MDNode *ScopeNode) {
762 DIVariable Cleansed = DV;
763 if (getExistingAbstractVariable(DV, Cleansed))
766 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
767 createAbstractVariable(Cleansed, Scope);
770 // Collect variable information from side table maintained by MMI.
771 void DwarfDebug::collectVariableInfoFromMMITable(
772 SmallPtrSetImpl<const MDNode *> &Processed) {
773 for (const auto &VI : MMI->getVariableDbgInfo()) {
776 Processed.insert(VI.Var);
777 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
779 // If variable scope is not found then skip this variable.
783 DIVariable DV(VI.Var);
784 DIExpression Expr(VI.Expr);
785 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
786 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
787 DbgVariable *RegVar = ConcreteVariables.back().get();
788 RegVar->setFrameIndex(VI.Slot);
789 InfoHolder.addScopeVariable(Scope, RegVar);
793 // Get .debug_loc entry for the instruction range starting at MI.
794 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
795 const MDNode *Expr = MI->getDebugExpression();
796 const MDNode *Var = MI->getDebugVariable();
798 assert(MI->getNumOperands() == 4);
799 if (MI->getOperand(0).isReg()) {
800 MachineLocation MLoc;
801 // If the second operand is an immediate, this is a
802 // register-indirect address.
803 if (!MI->getOperand(1).isImm())
804 MLoc.set(MI->getOperand(0).getReg());
806 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
807 return DebugLocEntry::Value(Var, Expr, MLoc);
809 if (MI->getOperand(0).isImm())
810 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
811 if (MI->getOperand(0).isFPImm())
812 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
813 if (MI->getOperand(0).isCImm())
814 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
816 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
819 /// Determine whether two variable pieces overlap.
820 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
821 if (!P1.isVariablePiece() || !P2.isVariablePiece())
823 unsigned l1 = P1.getPieceOffset();
824 unsigned l2 = P2.getPieceOffset();
825 unsigned r1 = l1 + P1.getPieceSize();
826 unsigned r2 = l2 + P2.getPieceSize();
827 // True where [l1,r1[ and [r1,r2[ overlap.
828 return (l1 < r2) && (l2 < r1);
831 /// Build the location list for all DBG_VALUEs in the function that
832 /// describe the same variable. If the ranges of several independent
833 /// pieces of the same variable overlap partially, split them up and
834 /// combine the ranges. The resulting DebugLocEntries are will have
835 /// strict monotonically increasing begin addresses and will never
840 // Ranges History [var, loc, piece ofs size]
841 // 0 | [x, (reg0, piece 0, 32)]
842 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
844 // 3 | [clobber reg0]
845 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
849 // [0-1] [x, (reg0, piece 0, 32)]
850 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
851 // [3-4] [x, (reg1, piece 32, 32)]
852 // [4- ] [x, (mem, piece 0, 64)]
854 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
855 const DbgValueHistoryMap::InstrRanges &Ranges) {
856 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
858 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
859 const MachineInstr *Begin = I->first;
860 const MachineInstr *End = I->second;
861 assert(Begin->isDebugValue() && "Invalid History entry");
863 // Check if a variable is inaccessible in this range.
864 if (Begin->getNumOperands() > 1 &&
865 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
870 // If this piece overlaps with any open ranges, truncate them.
871 DIExpression DIExpr = Begin->getDebugExpression();
872 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
873 [&](DebugLocEntry::Value R) {
874 return piecesOverlap(DIExpr, R.getExpression());
876 OpenRanges.erase(Last, OpenRanges.end());
878 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
879 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
881 const MCSymbol *EndLabel;
883 EndLabel = getLabelAfterInsn(End);
884 else if (std::next(I) == Ranges.end())
885 EndLabel = FunctionEndSym;
887 EndLabel = getLabelBeforeInsn(std::next(I)->first);
888 assert(EndLabel && "Forgot label after instruction ending a range!");
890 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
892 auto Value = getDebugLocValue(Begin);
893 DebugLocEntry Loc(StartLabel, EndLabel, Value);
894 bool couldMerge = false;
896 // If this is a piece, it may belong to the current DebugLocEntry.
897 if (DIExpr.isVariablePiece()) {
898 // Add this value to the list of open ranges.
899 OpenRanges.push_back(Value);
901 // Attempt to add the piece to the last entry.
902 if (!DebugLoc.empty())
903 if (DebugLoc.back().MergeValues(Loc))
908 // Need to add a new DebugLocEntry. Add all values from still
909 // valid non-overlapping pieces.
910 if (OpenRanges.size())
911 Loc.addValues(OpenRanges);
913 DebugLoc.push_back(std::move(Loc));
916 // Attempt to coalesce the ranges of two otherwise identical
918 auto CurEntry = DebugLoc.rbegin();
919 auto PrevEntry = std::next(CurEntry);
920 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
924 dbgs() << CurEntry->getValues().size() << " Values:\n";
925 for (auto Value : CurEntry->getValues()) {
926 Value.getVariable()->dump();
927 Value.getExpression()->dump();
935 // Find variables for each lexical scope.
937 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
938 SmallPtrSetImpl<const MDNode *> &Processed) {
939 // Grab the variable info that was squirreled away in the MMI side-table.
940 collectVariableInfoFromMMITable(Processed);
942 for (const auto &I : DbgValues) {
943 DIVariable DV(I.first);
944 if (Processed.count(DV))
947 // Instruction ranges, specifying where DV is accessible.
948 const auto &Ranges = I.second;
952 LexicalScope *Scope = nullptr;
953 if (MDNode *IA = DV.getInlinedAt()) {
954 DebugLoc DL = DebugLoc::getFromDILocation(IA);
955 Scope = LScopes.findInlinedScope(DebugLoc::get(
956 DL.getLine(), DL.getCol(), DV.getContext(), IA));
958 Scope = LScopes.findLexicalScope(DV.getContext());
959 // If variable scope is not found then skip this variable.
963 Processed.insert(DV);
964 const MachineInstr *MInsn = Ranges.front().first;
965 assert(MInsn->isDebugValue() && "History must begin with debug value");
966 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
967 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
968 DbgVariable *RegVar = ConcreteVariables.back().get();
969 InfoHolder.addScopeVariable(Scope, RegVar);
971 // Check if the first DBG_VALUE is valid for the rest of the function.
972 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
975 // Handle multiple DBG_VALUE instructions describing one variable.
976 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
978 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
979 DebugLocList &LocList = DotDebugLocEntries.back();
982 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
984 // Build the location list for this variable.
985 buildLocationList(LocList.List, Ranges);
988 // Collect info for variables that were optimized out.
989 DIArray Variables = SP.getVariables();
990 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
991 DIVariable DV(Variables.getElement(i));
992 assert(DV.isVariable());
993 if (!Processed.insert(DV).second)
995 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
996 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
998 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
999 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1004 // Return Label preceding the instruction.
1005 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1006 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1007 assert(Label && "Didn't insert label before instruction");
1011 // Return Label immediately following the instruction.
1012 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1013 return LabelsAfterInsn.lookup(MI);
1016 // Process beginning of an instruction.
1017 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1018 assert(CurMI == nullptr);
1020 // Check if source location changes, but ignore DBG_VALUE locations.
1021 if (!MI->isDebugValue()) {
1022 DebugLoc DL = MI->getDebugLoc();
1023 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1026 if (DL == PrologEndLoc) {
1027 Flags |= DWARF2_FLAG_PROLOGUE_END;
1028 PrologEndLoc = DebugLoc();
1029 Flags |= DWARF2_FLAG_IS_STMT;
1032 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
1033 Flags |= DWARF2_FLAG_IS_STMT;
1035 if (!DL.isUnknown()) {
1036 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1037 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1039 recordSourceLine(0, 0, nullptr, 0);
1043 // Insert labels where requested.
1044 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1045 LabelsBeforeInsn.find(MI);
1048 if (I == LabelsBeforeInsn.end())
1051 // Label already assigned.
1056 PrevLabel = MMI->getContext().CreateTempSymbol();
1057 Asm->OutStreamer.EmitLabel(PrevLabel);
1059 I->second = PrevLabel;
1062 // Process end of an instruction.
1063 void DwarfDebug::endInstruction() {
1064 assert(CurMI != nullptr);
1065 // Don't create a new label after DBG_VALUE instructions.
1066 // They don't generate code.
1067 if (!CurMI->isDebugValue())
1068 PrevLabel = nullptr;
1070 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1071 LabelsAfterInsn.find(CurMI);
1075 if (I == LabelsAfterInsn.end())
1078 // Label already assigned.
1082 // We need a label after this instruction.
1084 PrevLabel = MMI->getContext().CreateTempSymbol();
1085 Asm->OutStreamer.EmitLabel(PrevLabel);
1087 I->second = PrevLabel;
1090 // Each LexicalScope has first instruction and last instruction to mark
1091 // beginning and end of a scope respectively. Create an inverse map that list
1092 // scopes starts (and ends) with an instruction. One instruction may start (or
1093 // end) multiple scopes. Ignore scopes that are not reachable.
1094 void DwarfDebug::identifyScopeMarkers() {
1095 SmallVector<LexicalScope *, 4> WorkList;
1096 WorkList.push_back(LScopes.getCurrentFunctionScope());
1097 while (!WorkList.empty()) {
1098 LexicalScope *S = WorkList.pop_back_val();
1100 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1101 if (!Children.empty())
1102 WorkList.append(Children.begin(), Children.end());
1104 if (S->isAbstractScope())
1107 for (const InsnRange &R : S->getRanges()) {
1108 assert(R.first && "InsnRange does not have first instruction!");
1109 assert(R.second && "InsnRange does not have second instruction!");
1110 requestLabelBeforeInsn(R.first);
1111 requestLabelAfterInsn(R.second);
1116 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1117 // First known non-DBG_VALUE and non-frame setup location marks
1118 // the beginning of the function body.
1119 for (const auto &MBB : *MF)
1120 for (const auto &MI : MBB)
1121 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1122 !MI.getDebugLoc().isUnknown()) {
1123 // Did the target forget to set the FrameSetup flag for CFI insns?
1124 assert(!MI.isCFIInstruction() &&
1125 "First non-frame-setup instruction is a CFI instruction.");
1126 return MI.getDebugLoc();
1131 // Gather pre-function debug information. Assumes being called immediately
1132 // after the function entry point has been emitted.
1133 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1136 // If there's no debug info for the function we're not going to do anything.
1137 if (!MMI->hasDebugInfo())
1140 auto DI = FunctionDIs.find(MF->getFunction());
1141 if (DI == FunctionDIs.end())
1144 // Grab the lexical scopes for the function, if we don't have any of those
1145 // then we're not going to be able to do anything.
1146 LScopes.initialize(*MF);
1147 if (LScopes.empty())
1150 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1152 // Make sure that each lexical scope will have a begin/end label.
1153 identifyScopeMarkers();
1155 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1156 // belongs to so that we add to the correct per-cu line table in the
1158 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1159 // FnScope->getScopeNode() and DI->second should represent the same function,
1160 // though they may not be the same MDNode due to inline functions merged in
1161 // LTO where the debug info metadata still differs (either due to distinct
1162 // written differences - two versions of a linkonce_odr function
1163 // written/copied into two separate files, or some sub-optimal metadata that
1164 // isn't structurally identical (see: file path/name info from clang, which
1165 // includes the directory of the cpp file being built, even when the file name
1166 // is absolute (such as an <> lookup header)))
1167 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1168 assert(TheCU && "Unable to find compile unit!");
1169 if (Asm->OutStreamer.hasRawTextSupport())
1170 // Use a single line table if we are generating assembly.
1171 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1173 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1175 // Emit a label for the function so that we have a beginning address.
1176 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1177 // Assumes in correct section after the entry point.
1178 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1180 // Calculate history for local variables.
1181 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1184 // Request labels for the full history.
1185 for (const auto &I : DbgValues) {
1186 const auto &Ranges = I.second;
1190 // The first mention of a function argument gets the FunctionBeginSym
1191 // label, so arguments are visible when breaking at function entry.
1192 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1193 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1194 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1195 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1196 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1197 // Mark all non-overlapping initial pieces.
1198 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1199 DIExpression Piece = I->first->getDebugExpression();
1200 if (std::all_of(Ranges.begin(), I,
1201 [&](DbgValueHistoryMap::InstrRange Pred) {
1202 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1204 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1211 for (const auto &Range : Ranges) {
1212 requestLabelBeforeInsn(Range.first);
1214 requestLabelAfterInsn(Range.second);
1218 PrevInstLoc = DebugLoc();
1219 PrevLabel = FunctionBeginSym;
1221 // Record beginning of function.
1222 PrologEndLoc = findPrologueEndLoc(MF);
1223 if (!PrologEndLoc.isUnknown()) {
1224 DebugLoc FnStartDL =
1225 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1227 FnStartDL.getLine(), FnStartDL.getCol(),
1228 FnStartDL.getScope(MF->getFunction()->getContext()),
1229 // We'd like to list the prologue as "not statements" but GDB behaves
1230 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1231 DWARF2_FLAG_IS_STMT);
1235 // Gather and emit post-function debug information.
1236 void DwarfDebug::endFunction(const MachineFunction *MF) {
1237 assert(CurFn == MF &&
1238 "endFunction should be called with the same function as beginFunction");
1240 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1241 !FunctionDIs.count(MF->getFunction())) {
1242 // If we don't have a lexical scope for this function then there will
1243 // be a hole in the range information. Keep note of this by setting the
1244 // previously used section to nullptr.
1250 // Define end label for subprogram.
1251 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1252 // Assumes in correct section after the entry point.
1253 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1255 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1256 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1258 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1259 DISubprogram SP(FnScope->getScopeNode());
1260 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1262 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1263 collectVariableInfo(TheCU, SP, ProcessedVars);
1265 // Add the range of this function to the list of ranges for the CU.
1266 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1268 // Under -gmlt, skip building the subprogram if there are no inlined
1269 // subroutines inside it.
1270 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1271 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1272 assert(InfoHolder.getScopeVariables().empty());
1273 assert(DbgValues.empty());
1274 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1275 // by a -gmlt CU. Add a test and remove this assertion.
1276 assert(AbstractVariables.empty());
1277 LabelsBeforeInsn.clear();
1278 LabelsAfterInsn.clear();
1279 PrevLabel = nullptr;
1285 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1287 // Construct abstract scopes.
1288 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1289 DISubprogram SP(AScope->getScopeNode());
1290 assert(SP.isSubprogram());
1291 // Collect info for variables that were optimized out.
1292 DIArray Variables = SP.getVariables();
1293 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1294 DIVariable DV(Variables.getElement(i));
1295 assert(DV && DV.isVariable());
1296 if (!ProcessedVars.insert(DV).second)
1298 ensureAbstractVariableIsCreated(DV, DV.getContext());
1299 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1300 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1302 constructAbstractSubprogramScopeDIE(AScope);
1305 TheCU.constructSubprogramScopeDIE(FnScope);
1306 if (auto *SkelCU = TheCU.getSkeleton())
1307 if (!LScopes.getAbstractScopesList().empty())
1308 SkelCU->constructSubprogramScopeDIE(FnScope);
1311 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1312 // DbgVariables except those that are also in AbstractVariables (since they
1313 // can be used cross-function)
1314 InfoHolder.getScopeVariables().clear();
1316 LabelsBeforeInsn.clear();
1317 LabelsAfterInsn.clear();
1318 PrevLabel = nullptr;
1322 // Register a source line with debug info. Returns the unique label that was
1323 // emitted and which provides correspondence to the source line list.
1324 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1329 unsigned Discriminator = 0;
1330 if (DIScope Scope = DIScope(S)) {
1331 assert(Scope.isScope());
1332 Fn = Scope.getFilename();
1333 Dir = Scope.getDirectory();
1334 if (Scope.isLexicalBlockFile())
1335 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1337 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1338 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1339 .getOrCreateSourceID(Fn, Dir);
1341 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1345 //===----------------------------------------------------------------------===//
1347 //===----------------------------------------------------------------------===//
1349 // Emit initial Dwarf sections with a label at the start of each one.
1350 void DwarfDebug::emitSectionLabels() {
1351 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1353 // Dwarf sections base addresses.
1354 DwarfInfoSectionSym =
1355 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1356 if (useSplitDwarf()) {
1357 DwarfInfoDWOSectionSym =
1358 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1359 DwarfTypesDWOSectionSym =
1360 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1362 DwarfAbbrevSectionSym =
1363 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1364 if (useSplitDwarf())
1365 DwarfAbbrevDWOSectionSym = emitSectionSym(
1366 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1367 if (GenerateARangeSection)
1368 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1370 DwarfLineSectionSym =
1371 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1372 if (GenerateGnuPubSections) {
1373 DwarfGnuPubNamesSectionSym =
1374 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1375 DwarfGnuPubTypesSectionSym =
1376 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1377 } else if (HasDwarfPubSections) {
1378 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1379 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1382 DwarfStrSectionSym =
1383 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1384 if (useSplitDwarf()) {
1385 DwarfStrDWOSectionSym =
1386 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1387 DwarfAddrSectionSym =
1388 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1389 DwarfDebugLocSectionSym =
1390 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1392 DwarfDebugLocSectionSym =
1393 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1394 DwarfDebugRangeSectionSym =
1395 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1398 // Recursively emits a debug information entry.
1399 void DwarfDebug::emitDIE(DIE &Die) {
1400 // Get the abbreviation for this DIE.
1401 const DIEAbbrev &Abbrev = Die.getAbbrev();
1403 // Emit the code (index) for the abbreviation.
1404 if (Asm->isVerbose())
1405 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1406 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1407 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1408 dwarf::TagString(Abbrev.getTag()));
1409 Asm->EmitULEB128(Abbrev.getNumber());
1411 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1412 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1414 // Emit the DIE attribute values.
1415 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1416 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1417 dwarf::Form Form = AbbrevData[i].getForm();
1418 assert(Form && "Too many attributes for DIE (check abbreviation)");
1420 if (Asm->isVerbose()) {
1421 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1422 if (Attr == dwarf::DW_AT_accessibility)
1423 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1424 cast<DIEInteger>(Values[i])->getValue()));
1427 // Emit an attribute using the defined form.
1428 Values[i]->EmitValue(Asm, Form);
1431 // Emit the DIE children if any.
1432 if (Abbrev.hasChildren()) {
1433 for (auto &Child : Die.getChildren())
1436 Asm->OutStreamer.AddComment("End Of Children Mark");
1441 // Emit the debug info section.
1442 void DwarfDebug::emitDebugInfo() {
1443 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1445 Holder.emitUnits(DwarfAbbrevSectionSym);
1448 // Emit the abbreviation section.
1449 void DwarfDebug::emitAbbreviations() {
1450 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1452 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1455 // Emit the last address of the section and the end of the line matrix.
1456 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1457 // Define last address of section.
1458 Asm->OutStreamer.AddComment("Extended Op");
1461 Asm->OutStreamer.AddComment("Op size");
1462 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1463 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1464 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1466 Asm->OutStreamer.AddComment("Section end label");
1468 Asm->OutStreamer.EmitSymbolValue(
1469 Asm->GetTempSymbol("section_end", SectionEnd),
1470 Asm->getDataLayout().getPointerSize());
1472 // Mark end of matrix.
1473 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1479 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1480 StringRef TableName, StringRef SymName) {
1481 Accel.FinalizeTable(Asm, TableName);
1482 Asm->OutStreamer.SwitchSection(Section);
1483 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1484 Asm->OutStreamer.EmitLabel(SectionBegin);
1486 // Emit the full data.
1487 Accel.Emit(Asm, SectionBegin, this, DwarfStrSectionSym);
1490 // Emit visible names into a hashed accelerator table section.
1491 void DwarfDebug::emitAccelNames() {
1492 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1493 "Names", "names_begin");
1496 // Emit objective C classes and categories into a hashed accelerator table
1498 void DwarfDebug::emitAccelObjC() {
1499 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1500 "ObjC", "objc_begin");
1503 // Emit namespace dies into a hashed accelerator table.
1504 void DwarfDebug::emitAccelNamespaces() {
1505 emitAccel(AccelNamespace,
1506 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1507 "namespac", "namespac_begin");
1510 // Emit type dies into a hashed accelerator table.
1511 void DwarfDebug::emitAccelTypes() {
1512 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1513 "types", "types_begin");
1516 // Public name handling.
1517 // The format for the various pubnames:
1519 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1520 // for the DIE that is named.
1522 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1523 // into the CU and the index value is computed according to the type of value
1524 // for the DIE that is named.
1526 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1527 // it's the offset within the debug_info/debug_types dwo section, however, the
1528 // reference in the pubname header doesn't change.
1530 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1531 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1533 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1535 // We could have a specification DIE that has our most of our knowledge,
1536 // look for that now.
1537 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1539 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1540 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1541 Linkage = dwarf::GIEL_EXTERNAL;
1542 } else if (Die->findAttribute(dwarf::DW_AT_external))
1543 Linkage = dwarf::GIEL_EXTERNAL;
1545 switch (Die->getTag()) {
1546 case dwarf::DW_TAG_class_type:
1547 case dwarf::DW_TAG_structure_type:
1548 case dwarf::DW_TAG_union_type:
1549 case dwarf::DW_TAG_enumeration_type:
1550 return dwarf::PubIndexEntryDescriptor(
1551 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1552 ? dwarf::GIEL_STATIC
1553 : dwarf::GIEL_EXTERNAL);
1554 case dwarf::DW_TAG_typedef:
1555 case dwarf::DW_TAG_base_type:
1556 case dwarf::DW_TAG_subrange_type:
1557 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1558 case dwarf::DW_TAG_namespace:
1559 return dwarf::GIEK_TYPE;
1560 case dwarf::DW_TAG_subprogram:
1561 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1562 case dwarf::DW_TAG_constant:
1563 case dwarf::DW_TAG_variable:
1564 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1565 case dwarf::DW_TAG_enumerator:
1566 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1567 dwarf::GIEL_STATIC);
1569 return dwarf::GIEK_NONE;
1573 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1575 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1576 const MCSection *PSec =
1577 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1578 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1580 emitDebugPubSection(GnuStyle, PSec, "Names",
1581 &DwarfCompileUnit::getGlobalNames);
1584 void DwarfDebug::emitDebugPubSection(
1585 bool GnuStyle, const MCSection *PSec, StringRef Name,
1586 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1587 for (const auto &NU : CUMap) {
1588 DwarfCompileUnit *TheU = NU.second;
1590 const auto &Globals = (TheU->*Accessor)();
1592 if (Globals.empty())
1595 if (auto *Skeleton = TheU->getSkeleton())
1597 unsigned ID = TheU->getUniqueID();
1599 // Start the dwarf pubnames section.
1600 Asm->OutStreamer.SwitchSection(PSec);
1603 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1604 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1605 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1606 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1608 Asm->OutStreamer.EmitLabel(BeginLabel);
1610 Asm->OutStreamer.AddComment("DWARF Version");
1611 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1613 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1614 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1616 Asm->OutStreamer.AddComment("Compilation Unit Length");
1617 Asm->EmitInt32(TheU->getLength());
1619 // Emit the pubnames for this compilation unit.
1620 for (const auto &GI : Globals) {
1621 const char *Name = GI.getKeyData();
1622 const DIE *Entity = GI.second;
1624 Asm->OutStreamer.AddComment("DIE offset");
1625 Asm->EmitInt32(Entity->getOffset());
1628 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1629 Asm->OutStreamer.AddComment(
1630 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1631 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1632 Asm->EmitInt8(Desc.toBits());
1635 Asm->OutStreamer.AddComment("External Name");
1636 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1639 Asm->OutStreamer.AddComment("End Mark");
1641 Asm->OutStreamer.EmitLabel(EndLabel);
1645 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1646 const MCSection *PSec =
1647 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1648 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1650 emitDebugPubSection(GnuStyle, PSec, "Types",
1651 &DwarfCompileUnit::getGlobalTypes);
1654 // Emit visible names into a debug str section.
1655 void DwarfDebug::emitDebugStr() {
1656 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1657 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1660 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1661 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1662 const DITypeIdentifierMap &Map,
1663 ArrayRef<DebugLocEntry::Value> Values) {
1664 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1665 return P.isVariablePiece();
1666 }) && "all values are expected to be pieces");
1667 assert(std::is_sorted(Values.begin(), Values.end()) &&
1668 "pieces are expected to be sorted");
1670 unsigned Offset = 0;
1671 for (auto Piece : Values) {
1672 DIExpression Expr = Piece.getExpression();
1673 unsigned PieceOffset = Expr.getPieceOffset();
1674 unsigned PieceSize = Expr.getPieceSize();
1675 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1676 if (Offset < PieceOffset) {
1677 // The DWARF spec seriously mandates pieces with no locations for gaps.
1678 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1679 Offset += PieceOffset-Offset;
1682 Offset += PieceSize;
1684 const unsigned SizeOfByte = 8;
1686 DIVariable Var = Piece.getVariable();
1687 assert(!Var.isIndirect() && "indirect address for piece");
1688 unsigned VarSize = Var.getSizeInBits(Map);
1689 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1690 && "piece is larger than or outside of variable");
1691 assert(PieceSize*SizeOfByte != VarSize
1692 && "piece covers entire variable");
1694 if (Piece.isLocation() && Piece.getLoc().isReg())
1695 Asm->EmitDwarfRegOpPiece(Streamer,
1697 PieceSize*SizeOfByte);
1699 emitDebugLocValue(Streamer, Piece);
1700 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1706 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1707 const DebugLocEntry &Entry) {
1708 const DebugLocEntry::Value Value = Entry.getValues()[0];
1709 if (Value.isVariablePiece())
1710 // Emit all pieces that belong to the same variable and range.
1711 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1713 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1714 emitDebugLocValue(Streamer, Value);
1717 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1718 const DebugLocEntry::Value &Value) {
1719 DIVariable DV = Value.getVariable();
1721 if (Value.isInt()) {
1722 DIBasicType BTy(resolve(DV.getType()));
1723 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1724 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1725 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1726 Streamer.EmitSLEB128(Value.getInt());
1728 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1729 Streamer.EmitULEB128(Value.getInt());
1731 // The proper way to describe a constant value is
1732 // DW_OP_constu <const>, DW_OP_stack_value.
1733 // Unfortunately, DW_OP_stack_value was not available until DWARF-4,
1734 // so we will continue to generate DW_OP_constu <const> for DWARF-2
1735 // and DWARF-3. Technically, this is incorrect since DW_OP_const <const>
1736 // actually describes a value at a constant addess, not a constant value.
1737 // However, in the past there was no better way to describe a constant
1738 // value, so the producers and consumers started to rely on heuristics
1739 // to disambiguate the value vs. location status of the expression.
1740 // See PR21176 for more details.
1741 if (getDwarfVersion() >= 4)
1742 Streamer.EmitInt8(dwarf::DW_OP_stack_value, "DW_OP_stack_value");
1743 } else if (Value.isLocation()) {
1744 MachineLocation Loc = Value.getLoc();
1745 DIExpression Expr = Value.getExpression();
1748 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1750 // Complex address entry.
1751 unsigned N = Expr.getNumElements();
1753 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1754 if (Loc.getOffset()) {
1756 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1757 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1758 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1759 Streamer.EmitSLEB128(Expr.getElement(1));
1761 // If first address element is OpPlus then emit
1762 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1763 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1764 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1768 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1771 // Emit remaining complex address elements.
1772 for (; i < N; ++i) {
1773 uint64_t Element = Expr.getElement(i);
1774 if (Element == dwarf::DW_OP_plus) {
1775 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1776 Streamer.EmitULEB128(Expr.getElement(++i));
1777 } else if (Element == dwarf::DW_OP_deref) {
1779 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1780 } else if (Element == dwarf::DW_OP_piece) {
1782 // handled in emitDebugLocEntry.
1784 llvm_unreachable("unknown Opcode found in complex address");
1788 // else ... ignore constant fp. There is not any good way to
1789 // to represent them here in dwarf.
1793 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1794 Asm->OutStreamer.AddComment("Loc expr size");
1795 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1796 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1797 Asm->EmitLabelDifference(end, begin, 2);
1798 Asm->OutStreamer.EmitLabel(begin);
1800 APByteStreamer Streamer(*Asm);
1801 emitDebugLocEntry(Streamer, Entry);
1803 Asm->OutStreamer.EmitLabel(end);
1806 // Emit locations into the debug loc section.
1807 void DwarfDebug::emitDebugLoc() {
1808 // Start the dwarf loc section.
1809 Asm->OutStreamer.SwitchSection(
1810 Asm->getObjFileLowering().getDwarfLocSection());
1811 unsigned char Size = Asm->getDataLayout().getPointerSize();
1812 for (const auto &DebugLoc : DotDebugLocEntries) {
1813 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1814 const DwarfCompileUnit *CU = DebugLoc.CU;
1815 for (const auto &Entry : DebugLoc.List) {
1816 // Set up the range. This range is relative to the entry point of the
1817 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1818 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1819 if (auto *Base = CU->getBaseAddress()) {
1820 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1821 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1823 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1824 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1827 emitDebugLocEntryLocation(Entry);
1829 Asm->OutStreamer.EmitIntValue(0, Size);
1830 Asm->OutStreamer.EmitIntValue(0, Size);
1834 void DwarfDebug::emitDebugLocDWO() {
1835 Asm->OutStreamer.SwitchSection(
1836 Asm->getObjFileLowering().getDwarfLocDWOSection());
1837 for (const auto &DebugLoc : DotDebugLocEntries) {
1838 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1839 for (const auto &Entry : DebugLoc.List) {
1840 // Just always use start_length for now - at least that's one address
1841 // rather than two. We could get fancier and try to, say, reuse an
1842 // address we know we've emitted elsewhere (the start of the function?
1843 // The start of the CU or CU subrange that encloses this range?)
1844 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1845 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1846 Asm->EmitULEB128(idx);
1847 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1849 emitDebugLocEntryLocation(Entry);
1851 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1856 const MCSymbol *Start, *End;
1859 // Emit a debug aranges section, containing a CU lookup for any
1860 // address we can tie back to a CU.
1861 void DwarfDebug::emitDebugARanges() {
1862 // Start the dwarf aranges section.
1863 Asm->OutStreamer.SwitchSection(
1864 Asm->getObjFileLowering().getDwarfARangesSection());
1866 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1870 // Build a list of sections used.
1871 std::vector<const MCSection *> Sections;
1872 for (const auto &it : SectionMap) {
1873 const MCSection *Section = it.first;
1874 Sections.push_back(Section);
1877 // Sort the sections into order.
1878 // This is only done to ensure consistent output order across different runs.
1879 std::sort(Sections.begin(), Sections.end(), SectionSort);
1881 // Build a set of address spans, sorted by CU.
1882 for (const MCSection *Section : Sections) {
1883 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1884 if (List.size() < 2)
1887 // Sort the symbols by offset within the section.
1888 std::sort(List.begin(), List.end(),
1889 [&](const SymbolCU &A, const SymbolCU &B) {
1890 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1891 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1893 // Symbols with no order assigned should be placed at the end.
1894 // (e.g. section end labels)
1902 // If we have no section (e.g. common), just write out
1903 // individual spans for each symbol.
1905 for (const SymbolCU &Cur : List) {
1907 Span.Start = Cur.Sym;
1910 Spans[Cur.CU].push_back(Span);
1913 // Build spans between each label.
1914 const MCSymbol *StartSym = List[0].Sym;
1915 for (size_t n = 1, e = List.size(); n < e; n++) {
1916 const SymbolCU &Prev = List[n - 1];
1917 const SymbolCU &Cur = List[n];
1919 // Try and build the longest span we can within the same CU.
1920 if (Cur.CU != Prev.CU) {
1922 Span.Start = StartSym;
1924 Spans[Prev.CU].push_back(Span);
1931 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1933 // Build a list of CUs used.
1934 std::vector<DwarfCompileUnit *> CUs;
1935 for (const auto &it : Spans) {
1936 DwarfCompileUnit *CU = it.first;
1940 // Sort the CU list (again, to ensure consistent output order).
1941 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1942 return A->getUniqueID() < B->getUniqueID();
1945 // Emit an arange table for each CU we used.
1946 for (DwarfCompileUnit *CU : CUs) {
1947 std::vector<ArangeSpan> &List = Spans[CU];
1949 // Describe the skeleton CU's offset and length, not the dwo file's.
1950 if (auto *Skel = CU->getSkeleton())
1953 // Emit size of content not including length itself.
1954 unsigned ContentSize =
1955 sizeof(int16_t) + // DWARF ARange version number
1956 sizeof(int32_t) + // Offset of CU in the .debug_info section
1957 sizeof(int8_t) + // Pointer Size (in bytes)
1958 sizeof(int8_t); // Segment Size (in bytes)
1960 unsigned TupleSize = PtrSize * 2;
1962 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1964 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1966 ContentSize += Padding;
1967 ContentSize += (List.size() + 1) * TupleSize;
1969 // For each compile unit, write the list of spans it covers.
1970 Asm->OutStreamer.AddComment("Length of ARange Set");
1971 Asm->EmitInt32(ContentSize);
1972 Asm->OutStreamer.AddComment("DWARF Arange version number");
1973 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1974 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1975 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1976 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1977 Asm->EmitInt8(PtrSize);
1978 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1981 Asm->OutStreamer.EmitFill(Padding, 0xff);
1983 for (const ArangeSpan &Span : List) {
1984 Asm->EmitLabelReference(Span.Start, PtrSize);
1986 // Calculate the size as being from the span start to it's end.
1988 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1990 // For symbols without an end marker (e.g. common), we
1991 // write a single arange entry containing just that one symbol.
1992 uint64_t Size = SymSize[Span.Start];
1996 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2000 Asm->OutStreamer.AddComment("ARange terminator");
2001 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2002 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2006 // Emit visible names into a debug ranges section.
2007 void DwarfDebug::emitDebugRanges() {
2008 // Start the dwarf ranges section.
2009 Asm->OutStreamer.SwitchSection(
2010 Asm->getObjFileLowering().getDwarfRangesSection());
2012 // Size for our labels.
2013 unsigned char Size = Asm->getDataLayout().getPointerSize();
2015 // Grab the specific ranges for the compile units in the module.
2016 for (const auto &I : CUMap) {
2017 DwarfCompileUnit *TheCU = I.second;
2019 if (auto *Skel = TheCU->getSkeleton())
2022 // Iterate over the misc ranges for the compile units in the module.
2023 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2024 // Emit our symbol so we can find the beginning of the range.
2025 Asm->OutStreamer.EmitLabel(List.getSym());
2027 for (const RangeSpan &Range : List.getRanges()) {
2028 const MCSymbol *Begin = Range.getStart();
2029 const MCSymbol *End = Range.getEnd();
2030 assert(Begin && "Range without a begin symbol?");
2031 assert(End && "Range without an end symbol?");
2032 if (auto *Base = TheCU->getBaseAddress()) {
2033 Asm->EmitLabelDifference(Begin, Base, Size);
2034 Asm->EmitLabelDifference(End, Base, Size);
2036 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2037 Asm->OutStreamer.EmitSymbolValue(End, Size);
2041 // And terminate the list with two 0 values.
2042 Asm->OutStreamer.EmitIntValue(0, Size);
2043 Asm->OutStreamer.EmitIntValue(0, Size);
2048 // DWARF5 Experimental Separate Dwarf emitters.
2050 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2051 std::unique_ptr<DwarfUnit> NewU) {
2052 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
2053 U.getCUNode().getSplitDebugFilename());
2055 if (!CompilationDir.empty())
2056 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2058 addGnuPubAttributes(*NewU, Die);
2060 SkeletonHolder.addUnit(std::move(NewU));
2063 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2064 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2065 // DW_AT_addr_base, DW_AT_ranges_base.
2066 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2068 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2069 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2070 DwarfCompileUnit &NewCU = *OwnedUnit;
2071 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2072 DwarfInfoSectionSym);
2074 NewCU.initStmtList(DwarfLineSectionSym);
2076 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2081 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2082 // compile units that would normally be in debug_info.
2083 void DwarfDebug::emitDebugInfoDWO() {
2084 assert(useSplitDwarf() && "No split dwarf debug info?");
2085 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2086 // emit relocations into the dwo file.
2087 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2090 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2091 // abbreviations for the .debug_info.dwo section.
2092 void DwarfDebug::emitDebugAbbrevDWO() {
2093 assert(useSplitDwarf() && "No split dwarf?");
2094 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2097 void DwarfDebug::emitDebugLineDWO() {
2098 assert(useSplitDwarf() && "No split dwarf?");
2099 Asm->OutStreamer.SwitchSection(
2100 Asm->getObjFileLowering().getDwarfLineDWOSection());
2101 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2104 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2105 // string section and is identical in format to traditional .debug_str
2107 void DwarfDebug::emitDebugStrDWO() {
2108 assert(useSplitDwarf() && "No split dwarf?");
2109 const MCSection *OffSec =
2110 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2111 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2115 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2116 if (!useSplitDwarf())
2119 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2120 return &SplitTypeUnitFileTable;
2123 static uint64_t makeTypeSignature(StringRef Identifier) {
2125 Hash.update(Identifier);
2126 // ... take the least significant 8 bytes and return those. Our MD5
2127 // implementation always returns its results in little endian, swap bytes
2129 MD5::MD5Result Result;
2131 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2134 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2135 StringRef Identifier, DIE &RefDie,
2136 DICompositeType CTy) {
2137 // Fast path if we're building some type units and one has already used the
2138 // address pool we know we're going to throw away all this work anyway, so
2139 // don't bother building dependent types.
2140 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2143 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2145 CU.addDIETypeSignature(RefDie, *TU);
2149 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2150 AddrPool.resetUsedFlag();
2152 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2153 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2154 this, &InfoHolder, getDwoLineTable(CU));
2155 DwarfTypeUnit &NewTU = *OwnedUnit;
2156 DIE &UnitDie = NewTU.getUnitDie();
2158 TypeUnitsUnderConstruction.push_back(
2159 std::make_pair(std::move(OwnedUnit), CTy));
2161 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2164 uint64_t Signature = makeTypeSignature(Identifier);
2165 NewTU.setTypeSignature(Signature);
2167 if (useSplitDwarf())
2168 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2170 CU.applyStmtList(UnitDie);
2172 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2175 NewTU.setType(NewTU.createTypeDIE(CTy));
2178 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2179 TypeUnitsUnderConstruction.clear();
2181 // Types referencing entries in the address table cannot be placed in type
2183 if (AddrPool.hasBeenUsed()) {
2185 // Remove all the types built while building this type.
2186 // This is pessimistic as some of these types might not be dependent on
2187 // the type that used an address.
2188 for (const auto &TU : TypeUnitsToAdd)
2189 DwarfTypeUnits.erase(TU.second);
2191 // Construct this type in the CU directly.
2192 // This is inefficient because all the dependent types will be rebuilt
2193 // from scratch, including building them in type units, discovering that
2194 // they depend on addresses, throwing them out and rebuilding them.
2195 CU.constructTypeDIE(RefDie, CTy);
2199 // If the type wasn't dependent on fission addresses, finish adding the type
2200 // and all its dependent types.
2201 for (auto &TU : TypeUnitsToAdd)
2202 InfoHolder.addUnit(std::move(TU.first));
2204 CU.addDIETypeSignature(RefDie, NewTU);
2207 // Accelerator table mutators - add each name along with its companion
2208 // DIE to the proper table while ensuring that the name that we're going
2209 // to reference is in the string table. We do this since the names we
2210 // add may not only be identical to the names in the DIE.
2211 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2212 if (!useDwarfAccelTables())
2214 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2218 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2219 if (!useDwarfAccelTables())
2221 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2225 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2226 if (!useDwarfAccelTables())
2228 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2232 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2233 if (!useDwarfAccelTables())
2235 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),