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 (Value *N : CU_Nodes->operands()) {
454 DICompileUnit CUNode(cast<MDNode>(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 (Value *N : CU_Nodes->operands()) {
530 DICompileUnit TheCU(cast<MDNode>(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))
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();
1030 if (PrologEndLoc.isUnknown())
1031 Flags |= DWARF2_FLAG_IS_STMT;
1033 if (!DL.isUnknown()) {
1034 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1035 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1037 recordSourceLine(0, 0, nullptr, 0);
1041 // Insert labels where requested.
1042 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1043 LabelsBeforeInsn.find(MI);
1046 if (I == LabelsBeforeInsn.end())
1049 // Label already assigned.
1054 PrevLabel = MMI->getContext().CreateTempSymbol();
1055 Asm->OutStreamer.EmitLabel(PrevLabel);
1057 I->second = PrevLabel;
1060 // Process end of an instruction.
1061 void DwarfDebug::endInstruction() {
1062 assert(CurMI != nullptr);
1063 // Don't create a new label after DBG_VALUE instructions.
1064 // They don't generate code.
1065 if (!CurMI->isDebugValue())
1066 PrevLabel = nullptr;
1068 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1069 LabelsAfterInsn.find(CurMI);
1073 if (I == LabelsAfterInsn.end())
1076 // Label already assigned.
1080 // We need a label after this instruction.
1082 PrevLabel = MMI->getContext().CreateTempSymbol();
1083 Asm->OutStreamer.EmitLabel(PrevLabel);
1085 I->second = PrevLabel;
1088 // Each LexicalScope has first instruction and last instruction to mark
1089 // beginning and end of a scope respectively. Create an inverse map that list
1090 // scopes starts (and ends) with an instruction. One instruction may start (or
1091 // end) multiple scopes. Ignore scopes that are not reachable.
1092 void DwarfDebug::identifyScopeMarkers() {
1093 SmallVector<LexicalScope *, 4> WorkList;
1094 WorkList.push_back(LScopes.getCurrentFunctionScope());
1095 while (!WorkList.empty()) {
1096 LexicalScope *S = WorkList.pop_back_val();
1098 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1099 if (!Children.empty())
1100 WorkList.append(Children.begin(), Children.end());
1102 if (S->isAbstractScope())
1105 for (const InsnRange &R : S->getRanges()) {
1106 assert(R.first && "InsnRange does not have first instruction!");
1107 assert(R.second && "InsnRange does not have second instruction!");
1108 requestLabelBeforeInsn(R.first);
1109 requestLabelAfterInsn(R.second);
1114 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1115 // First known non-DBG_VALUE and non-frame setup location marks
1116 // the beginning of the function body.
1117 for (const auto &MBB : *MF)
1118 for (const auto &MI : MBB)
1119 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1120 !MI.getDebugLoc().isUnknown())
1121 return MI.getDebugLoc();
1125 // Gather pre-function debug information. Assumes being called immediately
1126 // after the function entry point has been emitted.
1127 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1130 // If there's no debug info for the function we're not going to do anything.
1131 if (!MMI->hasDebugInfo())
1134 auto DI = FunctionDIs.find(MF->getFunction());
1135 if (DI == FunctionDIs.end())
1138 // Grab the lexical scopes for the function, if we don't have any of those
1139 // then we're not going to be able to do anything.
1140 LScopes.initialize(*MF);
1141 if (LScopes.empty())
1144 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1146 // Make sure that each lexical scope will have a begin/end label.
1147 identifyScopeMarkers();
1149 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1150 // belongs to so that we add to the correct per-cu line table in the
1152 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1153 // FnScope->getScopeNode() and DI->second should represent the same function,
1154 // though they may not be the same MDNode due to inline functions merged in
1155 // LTO where the debug info metadata still differs (either due to distinct
1156 // written differences - two versions of a linkonce_odr function
1157 // written/copied into two separate files, or some sub-optimal metadata that
1158 // isn't structurally identical (see: file path/name info from clang, which
1159 // includes the directory of the cpp file being built, even when the file name
1160 // is absolute (such as an <> lookup header)))
1161 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1162 assert(TheCU && "Unable to find compile unit!");
1163 if (Asm->OutStreamer.hasRawTextSupport())
1164 // Use a single line table if we are generating assembly.
1165 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1167 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1169 // Emit a label for the function so that we have a beginning address.
1170 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1171 // Assumes in correct section after the entry point.
1172 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1174 // Calculate history for local variables.
1175 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1178 // Request labels for the full history.
1179 for (const auto &I : DbgValues) {
1180 const auto &Ranges = I.second;
1184 // The first mention of a function argument gets the FunctionBeginSym
1185 // label, so arguments are visible when breaking at function entry.
1186 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1187 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1188 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1189 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1190 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1191 // Mark all non-overlapping initial pieces.
1192 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1193 DIExpression Piece = I->first->getDebugExpression();
1194 if (std::all_of(Ranges.begin(), I,
1195 [&](DbgValueHistoryMap::InstrRange Pred) {
1196 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1198 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1205 for (const auto &Range : Ranges) {
1206 requestLabelBeforeInsn(Range.first);
1208 requestLabelAfterInsn(Range.second);
1212 PrevInstLoc = DebugLoc();
1213 PrevLabel = FunctionBeginSym;
1215 // Record beginning of function.
1216 PrologEndLoc = findPrologueEndLoc(MF);
1217 if (!PrologEndLoc.isUnknown()) {
1218 DebugLoc FnStartDL =
1219 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1221 FnStartDL.getLine(), FnStartDL.getCol(),
1222 FnStartDL.getScope(MF->getFunction()->getContext()),
1223 // We'd like to list the prologue as "not statements" but GDB behaves
1224 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1225 DWARF2_FLAG_IS_STMT);
1229 // Gather and emit post-function debug information.
1230 void DwarfDebug::endFunction(const MachineFunction *MF) {
1231 assert(CurFn == MF &&
1232 "endFunction should be called with the same function as beginFunction");
1234 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1235 !FunctionDIs.count(MF->getFunction())) {
1236 // If we don't have a lexical scope for this function then there will
1237 // be a hole in the range information. Keep note of this by setting the
1238 // previously used section to nullptr.
1244 // Define end label for subprogram.
1245 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1246 // Assumes in correct section after the entry point.
1247 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1249 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1250 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1252 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1253 DISubprogram SP(FnScope->getScopeNode());
1254 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1256 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1257 collectVariableInfo(TheCU, SP, ProcessedVars);
1259 // Add the range of this function to the list of ranges for the CU.
1260 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1262 // Under -gmlt, skip building the subprogram if there are no inlined
1263 // subroutines inside it.
1264 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1265 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1266 assert(InfoHolder.getScopeVariables().empty());
1267 assert(DbgValues.empty());
1268 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1269 // by a -gmlt CU. Add a test and remove this assertion.
1270 assert(AbstractVariables.empty());
1271 LabelsBeforeInsn.clear();
1272 LabelsAfterInsn.clear();
1273 PrevLabel = nullptr;
1279 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1281 // Construct abstract scopes.
1282 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1283 DISubprogram SP(AScope->getScopeNode());
1284 assert(SP.isSubprogram());
1285 // Collect info for variables that were optimized out.
1286 DIArray Variables = SP.getVariables();
1287 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1288 DIVariable DV(Variables.getElement(i));
1289 assert(DV && DV.isVariable());
1290 if (!ProcessedVars.insert(DV))
1292 ensureAbstractVariableIsCreated(DV, DV.getContext());
1293 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1294 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1296 constructAbstractSubprogramScopeDIE(AScope);
1299 TheCU.constructSubprogramScopeDIE(FnScope);
1300 if (auto *SkelCU = TheCU.getSkeleton())
1301 if (!LScopes.getAbstractScopesList().empty())
1302 SkelCU->constructSubprogramScopeDIE(FnScope);
1305 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1306 // DbgVariables except those that are also in AbstractVariables (since they
1307 // can be used cross-function)
1308 InfoHolder.getScopeVariables().clear();
1310 LabelsBeforeInsn.clear();
1311 LabelsAfterInsn.clear();
1312 PrevLabel = nullptr;
1316 // Register a source line with debug info. Returns the unique label that was
1317 // emitted and which provides correspondence to the source line list.
1318 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1323 unsigned Discriminator = 0;
1324 if (DIScope Scope = DIScope(S)) {
1325 assert(Scope.isScope());
1326 Fn = Scope.getFilename();
1327 Dir = Scope.getDirectory();
1328 if (Scope.isLexicalBlockFile())
1329 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1331 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1332 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1333 .getOrCreateSourceID(Fn, Dir);
1335 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1339 //===----------------------------------------------------------------------===//
1341 //===----------------------------------------------------------------------===//
1343 // Emit initial Dwarf sections with a label at the start of each one.
1344 void DwarfDebug::emitSectionLabels() {
1345 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1347 // Dwarf sections base addresses.
1348 DwarfInfoSectionSym =
1349 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1350 if (useSplitDwarf()) {
1351 DwarfInfoDWOSectionSym =
1352 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1353 DwarfTypesDWOSectionSym =
1354 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1356 DwarfAbbrevSectionSym =
1357 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1358 if (useSplitDwarf())
1359 DwarfAbbrevDWOSectionSym = emitSectionSym(
1360 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1361 if (GenerateARangeSection)
1362 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1364 DwarfLineSectionSym =
1365 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1366 if (GenerateGnuPubSections) {
1367 DwarfGnuPubNamesSectionSym =
1368 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1369 DwarfGnuPubTypesSectionSym =
1370 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1371 } else if (HasDwarfPubSections) {
1372 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1373 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1376 DwarfStrSectionSym =
1377 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1378 if (useSplitDwarf()) {
1379 DwarfStrDWOSectionSym =
1380 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1381 DwarfAddrSectionSym =
1382 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1383 DwarfDebugLocSectionSym =
1384 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1386 DwarfDebugLocSectionSym =
1387 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1388 DwarfDebugRangeSectionSym =
1389 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1392 // Recursively emits a debug information entry.
1393 void DwarfDebug::emitDIE(DIE &Die) {
1394 // Get the abbreviation for this DIE.
1395 const DIEAbbrev &Abbrev = Die.getAbbrev();
1397 // Emit the code (index) for the abbreviation.
1398 if (Asm->isVerbose())
1399 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1400 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1401 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1402 dwarf::TagString(Abbrev.getTag()));
1403 Asm->EmitULEB128(Abbrev.getNumber());
1405 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1406 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1408 // Emit the DIE attribute values.
1409 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1410 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1411 dwarf::Form Form = AbbrevData[i].getForm();
1412 assert(Form && "Too many attributes for DIE (check abbreviation)");
1414 if (Asm->isVerbose()) {
1415 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1416 if (Attr == dwarf::DW_AT_accessibility)
1417 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1418 cast<DIEInteger>(Values[i])->getValue()));
1421 // Emit an attribute using the defined form.
1422 Values[i]->EmitValue(Asm, Form);
1425 // Emit the DIE children if any.
1426 if (Abbrev.hasChildren()) {
1427 for (auto &Child : Die.getChildren())
1430 Asm->OutStreamer.AddComment("End Of Children Mark");
1435 // Emit the debug info section.
1436 void DwarfDebug::emitDebugInfo() {
1437 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1439 Holder.emitUnits(DwarfAbbrevSectionSym);
1442 // Emit the abbreviation section.
1443 void DwarfDebug::emitAbbreviations() {
1444 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1446 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1449 // Emit the last address of the section and the end of the line matrix.
1450 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1451 // Define last address of section.
1452 Asm->OutStreamer.AddComment("Extended Op");
1455 Asm->OutStreamer.AddComment("Op size");
1456 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1457 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1458 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1460 Asm->OutStreamer.AddComment("Section end label");
1462 Asm->OutStreamer.EmitSymbolValue(
1463 Asm->GetTempSymbol("section_end", SectionEnd),
1464 Asm->getDataLayout().getPointerSize());
1466 // Mark end of matrix.
1467 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1473 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1474 StringRef TableName, StringRef SymName) {
1475 Accel.FinalizeTable(Asm, TableName);
1476 Asm->OutStreamer.SwitchSection(Section);
1477 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1478 Asm->OutStreamer.EmitLabel(SectionBegin);
1480 // Emit the full data.
1481 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1484 // Emit visible names into a hashed accelerator table section.
1485 void DwarfDebug::emitAccelNames() {
1486 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1487 "Names", "names_begin");
1490 // Emit objective C classes and categories into a hashed accelerator table
1492 void DwarfDebug::emitAccelObjC() {
1493 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1494 "ObjC", "objc_begin");
1497 // Emit namespace dies into a hashed accelerator table.
1498 void DwarfDebug::emitAccelNamespaces() {
1499 emitAccel(AccelNamespace,
1500 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1501 "namespac", "namespac_begin");
1504 // Emit type dies into a hashed accelerator table.
1505 void DwarfDebug::emitAccelTypes() {
1506 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1507 "types", "types_begin");
1510 // Public name handling.
1511 // The format for the various pubnames:
1513 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1514 // for the DIE that is named.
1516 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1517 // into the CU and the index value is computed according to the type of value
1518 // for the DIE that is named.
1520 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1521 // it's the offset within the debug_info/debug_types dwo section, however, the
1522 // reference in the pubname header doesn't change.
1524 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1525 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1527 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1529 // We could have a specification DIE that has our most of our knowledge,
1530 // look for that now.
1531 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1533 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1534 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1535 Linkage = dwarf::GIEL_EXTERNAL;
1536 } else if (Die->findAttribute(dwarf::DW_AT_external))
1537 Linkage = dwarf::GIEL_EXTERNAL;
1539 switch (Die->getTag()) {
1540 case dwarf::DW_TAG_class_type:
1541 case dwarf::DW_TAG_structure_type:
1542 case dwarf::DW_TAG_union_type:
1543 case dwarf::DW_TAG_enumeration_type:
1544 return dwarf::PubIndexEntryDescriptor(
1545 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1546 ? dwarf::GIEL_STATIC
1547 : dwarf::GIEL_EXTERNAL);
1548 case dwarf::DW_TAG_typedef:
1549 case dwarf::DW_TAG_base_type:
1550 case dwarf::DW_TAG_subrange_type:
1551 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1552 case dwarf::DW_TAG_namespace:
1553 return dwarf::GIEK_TYPE;
1554 case dwarf::DW_TAG_subprogram:
1555 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1556 case dwarf::DW_TAG_constant:
1557 case dwarf::DW_TAG_variable:
1558 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1559 case dwarf::DW_TAG_enumerator:
1560 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1561 dwarf::GIEL_STATIC);
1563 return dwarf::GIEK_NONE;
1567 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1569 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1570 const MCSection *PSec =
1571 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1572 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1574 emitDebugPubSection(GnuStyle, PSec, "Names",
1575 &DwarfCompileUnit::getGlobalNames);
1578 void DwarfDebug::emitDebugPubSection(
1579 bool GnuStyle, const MCSection *PSec, StringRef Name,
1580 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1581 for (const auto &NU : CUMap) {
1582 DwarfCompileUnit *TheU = NU.second;
1584 const auto &Globals = (TheU->*Accessor)();
1586 if (Globals.empty())
1589 if (auto *Skeleton = TheU->getSkeleton())
1591 unsigned ID = TheU->getUniqueID();
1593 // Start the dwarf pubnames section.
1594 Asm->OutStreamer.SwitchSection(PSec);
1597 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1598 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1599 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1600 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1602 Asm->OutStreamer.EmitLabel(BeginLabel);
1604 Asm->OutStreamer.AddComment("DWARF Version");
1605 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1607 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1608 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1610 Asm->OutStreamer.AddComment("Compilation Unit Length");
1611 Asm->EmitInt32(TheU->getLength());
1613 // Emit the pubnames for this compilation unit.
1614 for (const auto &GI : Globals) {
1615 const char *Name = GI.getKeyData();
1616 const DIE *Entity = GI.second;
1618 Asm->OutStreamer.AddComment("DIE offset");
1619 Asm->EmitInt32(Entity->getOffset());
1622 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1623 Asm->OutStreamer.AddComment(
1624 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1625 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1626 Asm->EmitInt8(Desc.toBits());
1629 Asm->OutStreamer.AddComment("External Name");
1630 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1633 Asm->OutStreamer.AddComment("End Mark");
1635 Asm->OutStreamer.EmitLabel(EndLabel);
1639 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1640 const MCSection *PSec =
1641 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1642 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1644 emitDebugPubSection(GnuStyle, PSec, "Types",
1645 &DwarfCompileUnit::getGlobalTypes);
1648 // Emit visible names into a debug str section.
1649 void DwarfDebug::emitDebugStr() {
1650 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1651 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1654 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1655 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1656 const DITypeIdentifierMap &Map,
1657 ArrayRef<DebugLocEntry::Value> Values) {
1658 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1659 return P.isVariablePiece();
1660 }) && "all values are expected to be pieces");
1661 assert(std::is_sorted(Values.begin(), Values.end()) &&
1662 "pieces are expected to be sorted");
1664 unsigned Offset = 0;
1665 for (auto Piece : Values) {
1666 DIExpression Expr = Piece.getExpression();
1667 unsigned PieceOffset = Expr.getPieceOffset();
1668 unsigned PieceSize = Expr.getPieceSize();
1669 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1670 if (Offset < PieceOffset) {
1671 // The DWARF spec seriously mandates pieces with no locations for gaps.
1672 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1673 Offset += PieceOffset-Offset;
1676 Offset += PieceSize;
1678 const unsigned SizeOfByte = 8;
1680 DIVariable Var = Piece.getVariable();
1681 assert(!Var.isIndirect() && "indirect address for piece");
1682 unsigned VarSize = Var.getSizeInBits(Map);
1683 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1684 && "piece is larger than or outside of variable");
1685 assert(PieceSize*SizeOfByte != VarSize
1686 && "piece covers entire variable");
1688 if (Piece.isLocation() && Piece.getLoc().isReg())
1689 Asm->EmitDwarfRegOpPiece(Streamer,
1691 PieceSize*SizeOfByte);
1693 emitDebugLocValue(Streamer, Piece);
1694 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1700 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1701 const DebugLocEntry &Entry) {
1702 const DebugLocEntry::Value Value = Entry.getValues()[0];
1703 if (Value.isVariablePiece())
1704 // Emit all pieces that belong to the same variable and range.
1705 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1707 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1708 emitDebugLocValue(Streamer, Value);
1711 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1712 const DebugLocEntry::Value &Value) {
1713 DIVariable DV = Value.getVariable();
1715 if (Value.isInt()) {
1716 DIBasicType BTy(resolve(DV.getType()));
1717 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1718 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1719 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1720 Streamer.EmitSLEB128(Value.getInt());
1722 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1723 Streamer.EmitULEB128(Value.getInt());
1725 } else if (Value.isLocation()) {
1726 MachineLocation Loc = Value.getLoc();
1727 DIExpression Expr = Value.getExpression();
1730 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1732 // Complex address entry.
1733 unsigned N = Expr.getNumElements();
1735 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1736 if (Loc.getOffset()) {
1738 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1739 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1740 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1741 Streamer.EmitSLEB128(Expr.getElement(1));
1743 // If first address element is OpPlus then emit
1744 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1745 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1746 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1750 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1753 // Emit remaining complex address elements.
1754 for (; i < N; ++i) {
1755 uint64_t Element = Expr.getElement(i);
1756 if (Element == dwarf::DW_OP_plus) {
1757 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1758 Streamer.EmitULEB128(Expr.getElement(++i));
1759 } else if (Element == dwarf::DW_OP_deref) {
1761 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1762 } else if (Element == dwarf::DW_OP_piece) {
1764 // handled in emitDebugLocEntry.
1766 llvm_unreachable("unknown Opcode found in complex address");
1770 // else ... ignore constant fp. There is not any good way to
1771 // to represent them here in dwarf.
1775 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1776 Asm->OutStreamer.AddComment("Loc expr size");
1777 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1778 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1779 Asm->EmitLabelDifference(end, begin, 2);
1780 Asm->OutStreamer.EmitLabel(begin);
1782 APByteStreamer Streamer(*Asm);
1783 emitDebugLocEntry(Streamer, Entry);
1785 Asm->OutStreamer.EmitLabel(end);
1788 // Emit locations into the debug loc section.
1789 void DwarfDebug::emitDebugLoc() {
1790 // Start the dwarf loc section.
1791 Asm->OutStreamer.SwitchSection(
1792 Asm->getObjFileLowering().getDwarfLocSection());
1793 unsigned char Size = Asm->getDataLayout().getPointerSize();
1794 for (const auto &DebugLoc : DotDebugLocEntries) {
1795 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1796 const DwarfCompileUnit *CU = DebugLoc.CU;
1797 for (const auto &Entry : DebugLoc.List) {
1798 // Set up the range. This range is relative to the entry point of the
1799 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1800 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1801 if (auto *Base = CU->getBaseAddress()) {
1802 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1803 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1805 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1806 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1809 emitDebugLocEntryLocation(Entry);
1811 Asm->OutStreamer.EmitIntValue(0, Size);
1812 Asm->OutStreamer.EmitIntValue(0, Size);
1816 void DwarfDebug::emitDebugLocDWO() {
1817 Asm->OutStreamer.SwitchSection(
1818 Asm->getObjFileLowering().getDwarfLocDWOSection());
1819 for (const auto &DebugLoc : DotDebugLocEntries) {
1820 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1821 for (const auto &Entry : DebugLoc.List) {
1822 // Just always use start_length for now - at least that's one address
1823 // rather than two. We could get fancier and try to, say, reuse an
1824 // address we know we've emitted elsewhere (the start of the function?
1825 // The start of the CU or CU subrange that encloses this range?)
1826 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1827 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1828 Asm->EmitULEB128(idx);
1829 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1831 emitDebugLocEntryLocation(Entry);
1833 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1838 const MCSymbol *Start, *End;
1841 // Emit a debug aranges section, containing a CU lookup for any
1842 // address we can tie back to a CU.
1843 void DwarfDebug::emitDebugARanges() {
1844 // Start the dwarf aranges section.
1845 Asm->OutStreamer.SwitchSection(
1846 Asm->getObjFileLowering().getDwarfARangesSection());
1848 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1852 // Build a list of sections used.
1853 std::vector<const MCSection *> Sections;
1854 for (const auto &it : SectionMap) {
1855 const MCSection *Section = it.first;
1856 Sections.push_back(Section);
1859 // Sort the sections into order.
1860 // This is only done to ensure consistent output order across different runs.
1861 std::sort(Sections.begin(), Sections.end(), SectionSort);
1863 // Build a set of address spans, sorted by CU.
1864 for (const MCSection *Section : Sections) {
1865 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1866 if (List.size() < 2)
1869 // Sort the symbols by offset within the section.
1870 std::sort(List.begin(), List.end(),
1871 [&](const SymbolCU &A, const SymbolCU &B) {
1872 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1873 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1875 // Symbols with no order assigned should be placed at the end.
1876 // (e.g. section end labels)
1884 // If we have no section (e.g. common), just write out
1885 // individual spans for each symbol.
1887 for (const SymbolCU &Cur : List) {
1889 Span.Start = Cur.Sym;
1892 Spans[Cur.CU].push_back(Span);
1895 // Build spans between each label.
1896 const MCSymbol *StartSym = List[0].Sym;
1897 for (size_t n = 1, e = List.size(); n < e; n++) {
1898 const SymbolCU &Prev = List[n - 1];
1899 const SymbolCU &Cur = List[n];
1901 // Try and build the longest span we can within the same CU.
1902 if (Cur.CU != Prev.CU) {
1904 Span.Start = StartSym;
1906 Spans[Prev.CU].push_back(Span);
1913 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1915 // Build a list of CUs used.
1916 std::vector<DwarfCompileUnit *> CUs;
1917 for (const auto &it : Spans) {
1918 DwarfCompileUnit *CU = it.first;
1922 // Sort the CU list (again, to ensure consistent output order).
1923 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1924 return A->getUniqueID() < B->getUniqueID();
1927 // Emit an arange table for each CU we used.
1928 for (DwarfCompileUnit *CU : CUs) {
1929 std::vector<ArangeSpan> &List = Spans[CU];
1931 // Describe the skeleton CU's offset and length, not the dwo file's.
1932 if (auto *Skel = CU->getSkeleton())
1935 // Emit size of content not including length itself.
1936 unsigned ContentSize =
1937 sizeof(int16_t) + // DWARF ARange version number
1938 sizeof(int32_t) + // Offset of CU in the .debug_info section
1939 sizeof(int8_t) + // Pointer Size (in bytes)
1940 sizeof(int8_t); // Segment Size (in bytes)
1942 unsigned TupleSize = PtrSize * 2;
1944 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1946 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1948 ContentSize += Padding;
1949 ContentSize += (List.size() + 1) * TupleSize;
1951 // For each compile unit, write the list of spans it covers.
1952 Asm->OutStreamer.AddComment("Length of ARange Set");
1953 Asm->EmitInt32(ContentSize);
1954 Asm->OutStreamer.AddComment("DWARF Arange version number");
1955 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1956 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1957 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1958 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1959 Asm->EmitInt8(PtrSize);
1960 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1963 Asm->OutStreamer.EmitFill(Padding, 0xff);
1965 for (const ArangeSpan &Span : List) {
1966 Asm->EmitLabelReference(Span.Start, PtrSize);
1968 // Calculate the size as being from the span start to it's end.
1970 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1972 // For symbols without an end marker (e.g. common), we
1973 // write a single arange entry containing just that one symbol.
1974 uint64_t Size = SymSize[Span.Start];
1978 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1982 Asm->OutStreamer.AddComment("ARange terminator");
1983 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1984 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1988 // Emit visible names into a debug ranges section.
1989 void DwarfDebug::emitDebugRanges() {
1990 // Start the dwarf ranges section.
1991 Asm->OutStreamer.SwitchSection(
1992 Asm->getObjFileLowering().getDwarfRangesSection());
1994 // Size for our labels.
1995 unsigned char Size = Asm->getDataLayout().getPointerSize();
1997 // Grab the specific ranges for the compile units in the module.
1998 for (const auto &I : CUMap) {
1999 DwarfCompileUnit *TheCU = I.second;
2001 if (auto *Skel = TheCU->getSkeleton())
2004 // Iterate over the misc ranges for the compile units in the module.
2005 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2006 // Emit our symbol so we can find the beginning of the range.
2007 Asm->OutStreamer.EmitLabel(List.getSym());
2009 for (const RangeSpan &Range : List.getRanges()) {
2010 const MCSymbol *Begin = Range.getStart();
2011 const MCSymbol *End = Range.getEnd();
2012 assert(Begin && "Range without a begin symbol?");
2013 assert(End && "Range without an end symbol?");
2014 if (auto *Base = TheCU->getBaseAddress()) {
2015 Asm->EmitLabelDifference(Begin, Base, Size);
2016 Asm->EmitLabelDifference(End, Base, Size);
2018 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2019 Asm->OutStreamer.EmitSymbolValue(End, Size);
2023 // And terminate the list with two 0 values.
2024 Asm->OutStreamer.EmitIntValue(0, Size);
2025 Asm->OutStreamer.EmitIntValue(0, Size);
2030 // DWARF5 Experimental Separate Dwarf emitters.
2032 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2033 std::unique_ptr<DwarfUnit> NewU) {
2034 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
2035 U.getCUNode().getSplitDebugFilename());
2037 if (!CompilationDir.empty())
2038 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2040 addGnuPubAttributes(*NewU, Die);
2042 SkeletonHolder.addUnit(std::move(NewU));
2045 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2046 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2047 // DW_AT_addr_base, DW_AT_ranges_base.
2048 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2050 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2051 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2052 DwarfCompileUnit &NewCU = *OwnedUnit;
2053 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2054 DwarfInfoSectionSym);
2056 NewCU.initStmtList(DwarfLineSectionSym);
2058 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2063 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2064 // compile units that would normally be in debug_info.
2065 void DwarfDebug::emitDebugInfoDWO() {
2066 assert(useSplitDwarf() && "No split dwarf debug info?");
2067 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2068 // emit relocations into the dwo file.
2069 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2072 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2073 // abbreviations for the .debug_info.dwo section.
2074 void DwarfDebug::emitDebugAbbrevDWO() {
2075 assert(useSplitDwarf() && "No split dwarf?");
2076 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2079 void DwarfDebug::emitDebugLineDWO() {
2080 assert(useSplitDwarf() && "No split dwarf?");
2081 Asm->OutStreamer.SwitchSection(
2082 Asm->getObjFileLowering().getDwarfLineDWOSection());
2083 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2086 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2087 // string section and is identical in format to traditional .debug_str
2089 void DwarfDebug::emitDebugStrDWO() {
2090 assert(useSplitDwarf() && "No split dwarf?");
2091 const MCSection *OffSec =
2092 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2093 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2097 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2098 if (!useSplitDwarf())
2101 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2102 return &SplitTypeUnitFileTable;
2105 static uint64_t makeTypeSignature(StringRef Identifier) {
2107 Hash.update(Identifier);
2108 // ... take the least significant 8 bytes and return those. Our MD5
2109 // implementation always returns its results in little endian, swap bytes
2111 MD5::MD5Result Result;
2113 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2116 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2117 StringRef Identifier, DIE &RefDie,
2118 DICompositeType CTy) {
2119 // Fast path if we're building some type units and one has already used the
2120 // address pool we know we're going to throw away all this work anyway, so
2121 // don't bother building dependent types.
2122 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2125 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2127 CU.addDIETypeSignature(RefDie, *TU);
2131 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2132 AddrPool.resetUsedFlag();
2134 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2135 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2136 this, &InfoHolder, getDwoLineTable(CU));
2137 DwarfTypeUnit &NewTU = *OwnedUnit;
2138 DIE &UnitDie = NewTU.getUnitDie();
2140 TypeUnitsUnderConstruction.push_back(
2141 std::make_pair(std::move(OwnedUnit), CTy));
2143 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2146 uint64_t Signature = makeTypeSignature(Identifier);
2147 NewTU.setTypeSignature(Signature);
2149 if (useSplitDwarf())
2150 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2152 CU.applyStmtList(UnitDie);
2154 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2157 NewTU.setType(NewTU.createTypeDIE(CTy));
2160 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2161 TypeUnitsUnderConstruction.clear();
2163 // Types referencing entries in the address table cannot be placed in type
2165 if (AddrPool.hasBeenUsed()) {
2167 // Remove all the types built while building this type.
2168 // This is pessimistic as some of these types might not be dependent on
2169 // the type that used an address.
2170 for (const auto &TU : TypeUnitsToAdd)
2171 DwarfTypeUnits.erase(TU.second);
2173 // Construct this type in the CU directly.
2174 // This is inefficient because all the dependent types will be rebuilt
2175 // from scratch, including building them in type units, discovering that
2176 // they depend on addresses, throwing them out and rebuilding them.
2177 CU.constructTypeDIE(RefDie, CTy);
2181 // If the type wasn't dependent on fission addresses, finish adding the type
2182 // and all its dependent types.
2183 for (auto &TU : TypeUnitsToAdd)
2184 InfoHolder.addUnit(std::move(TU.first));
2186 CU.addDIETypeSignature(RefDie, NewTU);
2189 // Accelerator table mutators - add each name along with its companion
2190 // DIE to the proper table while ensuring that the name that we're going
2191 // to reference is in the string table. We do this since the names we
2192 // add may not only be identical to the names in the DIE.
2193 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2194 if (!useDwarfAccelTables())
2196 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2200 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2201 if (!useDwarfAccelTables())
2203 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2207 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2208 if (!useDwarfAccelTables())
2210 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2214 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2215 if (!useDwarfAccelTables())
2217 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),