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 "ByteStreamer.h"
15 #include "DwarfDebug.h"
18 #include "DwarfUnit.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/ADT/StringExtras.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineModuleInfo.h"
25 #include "llvm/IR/Constants.h"
26 #include "llvm/IR/DIBuilder.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DebugInfo.h"
29 #include "llvm/IR/Instructions.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/IR/ValueHandle.h"
32 #include "llvm/MC/MCAsmInfo.h"
33 #include "llvm/MC/MCSection.h"
34 #include "llvm/MC/MCStreamer.h"
35 #include "llvm/MC/MCSymbol.h"
36 #include "llvm/Support/CommandLine.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/Dwarf.h"
39 #include "llvm/Support/Endian.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/FormattedStream.h"
42 #include "llvm/Support/LEB128.h"
43 #include "llvm/Support/MD5.h"
44 #include "llvm/Support/Path.h"
45 #include "llvm/Support/Timer.h"
46 #include "llvm/Target/TargetFrameLowering.h"
47 #include "llvm/Target/TargetLoweringObjectFile.h"
48 #include "llvm/Target/TargetMachine.h"
49 #include "llvm/Target/TargetOptions.h"
50 #include "llvm/Target/TargetRegisterInfo.h"
51 #include "llvm/Target/TargetSubtargetInfo.h"
54 #define DEBUG_TYPE "dwarfdebug"
57 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
58 cl::desc("Disable debug info printing"));
60 static cl::opt<bool> UnknownLocations(
61 "use-unknown-locations", cl::Hidden,
62 cl::desc("Make an absence of debug location information explicit."),
66 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
67 cl::desc("Generate GNU-style pubnames and pubtypes"),
70 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
72 cl::desc("Generate dwarf aranges"),
76 enum DefaultOnOff { Default, Enable, Disable };
79 static cl::opt<DefaultOnOff>
80 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
81 cl::desc("Output prototype dwarf accelerator tables."),
82 cl::values(clEnumVal(Default, "Default for platform"),
83 clEnumVal(Enable, "Enabled"),
84 clEnumVal(Disable, "Disabled"), clEnumValEnd),
87 static cl::opt<DefaultOnOff>
88 SplitDwarf("split-dwarf", cl::Hidden,
89 cl::desc("Output DWARF5 split debug info."),
90 cl::values(clEnumVal(Default, "Default for platform"),
91 clEnumVal(Enable, "Enabled"),
92 clEnumVal(Disable, "Disabled"), clEnumValEnd),
95 static cl::opt<DefaultOnOff>
96 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
97 cl::desc("Generate DWARF pubnames and pubtypes sections"),
98 cl::values(clEnumVal(Default, "Default for platform"),
99 clEnumVal(Enable, "Enabled"),
100 clEnumVal(Disable, "Disabled"), clEnumValEnd),
103 static const char *const DWARFGroupName = "DWARF Emission";
104 static const char *const DbgTimerName = "DWARF Debug Writer";
106 //===----------------------------------------------------------------------===//
108 /// resolve - Look in the DwarfDebug map for the MDNode that
109 /// corresponds to the reference.
110 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
111 return DD->resolve(Ref);
114 bool DbgVariable::isBlockByrefVariable() const {
115 assert(Var.isVariable() && "Invalid complex DbgVariable!");
116 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
119 DIType DbgVariable::getType() const {
120 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
121 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
122 // addresses instead.
123 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
124 /* Byref variables, in Blocks, are declared by the programmer as
125 "SomeType VarName;", but the compiler creates a
126 __Block_byref_x_VarName struct, and gives the variable VarName
127 either the struct, or a pointer to the struct, as its type. This
128 is necessary for various behind-the-scenes things the compiler
129 needs to do with by-reference variables in blocks.
131 However, as far as the original *programmer* is concerned, the
132 variable should still have type 'SomeType', as originally declared.
134 The following function dives into the __Block_byref_x_VarName
135 struct to find the original type of the variable. This will be
136 passed back to the code generating the type for the Debug
137 Information Entry for the variable 'VarName'. 'VarName' will then
138 have the original type 'SomeType' in its debug information.
140 The original type 'SomeType' will be the type of the field named
141 'VarName' inside the __Block_byref_x_VarName struct.
143 NOTE: In order for this to not completely fail on the debugger
144 side, the Debug Information Entry for the variable VarName needs to
145 have a DW_AT_location that tells the debugger how to unwind through
146 the pointers and __Block_byref_x_VarName struct to find the actual
147 value of the variable. The function addBlockByrefType does this. */
149 uint16_t tag = Ty.getTag();
151 if (tag == dwarf::DW_TAG_pointer_type)
152 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
154 DIArray Elements = DICompositeType(subType).getElements();
155 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
156 DIDerivedType DT(Elements.getElement(i));
157 if (getName() == DT.getName())
158 return (resolve(DT.getTypeDerivedFrom()));
164 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
165 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
166 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
169 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
170 : Asm(A), MMI(Asm->MMI), FirstCU(nullptr), PrevLabel(nullptr),
171 GlobalRangeCount(0), InfoHolder(A, "info_string", DIEValueAllocator),
172 UsedNonDefaultText(false),
173 SkeletonHolder(A, "skel_string", DIEValueAllocator),
174 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
175 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
176 dwarf::DW_FORM_data4)),
177 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelTypes(TypeAtoms) {
183 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
184 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
185 DwarfLineSectionSym = nullptr;
186 DwarfAddrSectionSym = nullptr;
187 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
188 FunctionBeginSym = FunctionEndSym = nullptr;
192 // Turn on accelerator tables for Darwin by default, pubnames by
193 // default for non-Darwin, and handle split dwarf.
194 if (DwarfAccelTables == Default)
195 HasDwarfAccelTables = IsDarwin;
197 HasDwarfAccelTables = DwarfAccelTables == Enable;
199 if (SplitDwarf == Default)
200 HasSplitDwarf = false;
202 HasSplitDwarf = SplitDwarf == Enable;
204 if (DwarfPubSections == Default)
205 HasDwarfPubSections = !IsDarwin;
207 HasDwarfPubSections = DwarfPubSections == Enable;
209 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
210 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
211 : MMI->getModule()->getDwarfVersion();
213 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
216 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
221 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
222 DwarfDebug::~DwarfDebug() { }
224 // Switch to the specified MCSection and emit an assembler
225 // temporary label to it if SymbolStem is specified.
226 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
227 const char *SymbolStem = nullptr) {
228 Asm->OutStreamer.SwitchSection(Section);
232 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
233 Asm->OutStreamer.EmitLabel(TmpSym);
237 static bool isObjCClass(StringRef Name) {
238 return Name.startswith("+") || Name.startswith("-");
241 static bool hasObjCCategory(StringRef Name) {
242 if (!isObjCClass(Name))
245 return Name.find(") ") != StringRef::npos;
248 static void getObjCClassCategory(StringRef In, StringRef &Class,
249 StringRef &Category) {
250 if (!hasObjCCategory(In)) {
251 Class = In.slice(In.find('[') + 1, In.find(' '));
256 Class = In.slice(In.find('[') + 1, In.find('('));
257 Category = In.slice(In.find('[') + 1, In.find(' '));
261 static StringRef getObjCMethodName(StringRef In) {
262 return In.slice(In.find(' ') + 1, In.find(']'));
265 // Helper for sorting sections into a stable output order.
266 static bool SectionSort(const MCSection *A, const MCSection *B) {
267 std::string LA = (A ? A->getLabelBeginName() : "");
268 std::string LB = (B ? B->getLabelBeginName() : "");
272 // Add the various names to the Dwarf accelerator table names.
273 // TODO: Determine whether or not we should add names for programs
274 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
275 // is only slightly different than the lookup of non-standard ObjC names.
276 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
277 if (!SP.isDefinition())
279 addAccelName(SP.getName(), Die);
281 // If the linkage name is different than the name, go ahead and output
282 // that as well into the name table.
283 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
284 addAccelName(SP.getLinkageName(), Die);
286 // If this is an Objective-C selector name add it to the ObjC accelerator
288 if (isObjCClass(SP.getName())) {
289 StringRef Class, Category;
290 getObjCClassCategory(SP.getName(), Class, Category);
291 addAccelObjC(Class, Die);
293 addAccelObjC(Category, Die);
294 // Also add the base method name to the name table.
295 addAccelName(getObjCMethodName(SP.getName()), Die);
299 /// isSubprogramContext - Return true if Context is either a subprogram
300 /// or another context nested inside a subprogram.
301 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
304 DIDescriptor D(Context);
305 if (D.isSubprogram())
308 return isSubprogramContext(resolve(DIType(Context).getContext()));
312 // Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
313 // and DW_AT_high_pc attributes. If there are global variables in this
314 // scope then create and insert DIEs for these variables.
315 DIE &DwarfDebug::updateSubprogramScopeDIE(DwarfCompileUnit &SPCU,
317 DIE *SPDie = SPCU.getOrCreateSubprogramDIE(SP);
319 attachLowHighPC(SPCU, *SPDie, FunctionBeginSym, FunctionEndSym);
320 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
321 SPCU.addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
323 // Only include DW_AT_frame_base in full debug info
324 if (SPCU.getCUNode().getEmissionKind() != DIBuilder::LineTablesOnly) {
325 const TargetRegisterInfo *RI =
326 Asm->TM.getSubtargetImpl()->getRegisterInfo();
327 MachineLocation Location(RI->getFrameRegister(*Asm->MF));
328 SPCU.addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
331 // Add name to the name table, we do this here because we're guaranteed
332 // to have concrete versions of our DW_TAG_subprogram nodes.
333 addSubprogramNames(SP, *SPDie);
338 /// Check whether we should create a DIE for the given Scope, return true
339 /// if we don't create a DIE (the corresponding DIE is null).
340 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
341 if (Scope->isAbstractScope())
344 // We don't create a DIE if there is no Range.
345 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
349 if (Ranges.size() > 1)
352 // We don't create a DIE if we have a single Range and the end label
354 return !getLabelAfterInsn(Ranges.front().second);
357 static void addSectionLabel(AsmPrinter &Asm, DwarfUnit &U, DIE &D,
358 dwarf::Attribute A, const MCSymbol *L,
359 const MCSymbol *Sec) {
360 if (Asm.MAI->doesDwarfUseRelocationsAcrossSections())
361 U.addSectionLabel(D, A, L);
363 U.addSectionDelta(D, A, L, Sec);
366 void DwarfDebug::addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
367 const SmallVectorImpl<InsnRange> &Range) {
368 // Emit offset in .debug_range as a relocatable label. emitDIE will handle
369 // emitting it appropriately.
370 MCSymbol *RangeSym = Asm->GetTempSymbol("debug_ranges", GlobalRangeCount++);
372 // Under fission, ranges are specified by constant offsets relative to the
373 // CU's DW_AT_GNU_ranges_base.
375 TheCU.addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
376 DwarfDebugRangeSectionSym);
378 addSectionLabel(*Asm, TheCU, ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
379 DwarfDebugRangeSectionSym);
381 RangeSpanList List(RangeSym);
382 for (const InsnRange &R : Range) {
383 RangeSpan Span(getLabelBeforeInsn(R.first), getLabelAfterInsn(R.second));
384 List.addRange(std::move(Span));
387 // Add the range list to the set of ranges to be emitted.
388 TheCU.addRangeList(std::move(List));
391 void DwarfDebug::attachRangesOrLowHighPC(DwarfCompileUnit &TheCU, DIE &Die,
392 const SmallVectorImpl<InsnRange> &Ranges) {
393 assert(!Ranges.empty());
394 if (Ranges.size() == 1)
395 attachLowHighPC(TheCU, Die, getLabelBeforeInsn(Ranges.front().first),
396 getLabelAfterInsn(Ranges.front().second));
398 addScopeRangeList(TheCU, Die, Ranges);
401 // Construct new DW_TAG_lexical_block for this scope and attach
402 // DW_AT_low_pc/DW_AT_high_pc labels.
404 DwarfDebug::constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
405 LexicalScope *Scope) {
406 if (isLexicalScopeDIENull(Scope))
409 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
410 if (Scope->isAbstractScope())
413 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
418 // This scope represents inlined body of a function. Construct DIE to
419 // represent this concrete inlined copy of the function.
421 DwarfDebug::constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
422 LexicalScope *Scope) {
423 assert(Scope->getScopeNode());
424 DIScope DS(Scope->getScopeNode());
425 DISubprogram InlinedSP = getDISubprogram(DS);
426 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
427 // was inlined from another compile unit.
428 DIE *OriginDIE = AbstractSPDies[InlinedSP];
429 assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
431 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
432 TheCU.addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
434 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
436 InlinedSubprogramDIEs.insert(OriginDIE);
438 // Add the call site information to the DIE.
439 DILocation DL(Scope->getInlinedAt());
440 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
441 TheCU.getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
442 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
444 // Add name to the name table, we do this here because we're guaranteed
445 // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
446 addSubprogramNames(InlinedSP, *ScopeDIE);
451 static std::unique_ptr<DIE> constructVariableDIE(DwarfCompileUnit &TheCU,
453 const LexicalScope &Scope,
454 DIE *&ObjectPointer) {
455 auto Var = TheCU.constructVariableDIE(DV, Scope.isAbstractScope());
456 if (DV.isObjectPointer())
457 ObjectPointer = Var.get();
461 DIE *DwarfDebug::createScopeChildrenDIE(
462 DwarfCompileUnit &TheCU, LexicalScope *Scope,
463 SmallVectorImpl<std::unique_ptr<DIE>> &Children,
464 unsigned *ChildScopeCount) {
465 DIE *ObjectPointer = nullptr;
467 for (DbgVariable *DV : ScopeVariables.lookup(Scope))
468 Children.push_back(constructVariableDIE(TheCU, *DV, *Scope, ObjectPointer));
470 unsigned ChildCountWithoutScopes = Children.size();
472 for (LexicalScope *LS : Scope->getChildren())
473 constructScopeDIE(TheCU, LS, Children);
476 *ChildScopeCount = Children.size() - ChildCountWithoutScopes;
478 return ObjectPointer;
481 DIE *DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU,
482 LexicalScope *Scope, DIE &ScopeDIE) {
483 // We create children when the scope DIE is not null.
484 SmallVector<std::unique_ptr<DIE>, 8> Children;
485 DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children);
488 for (auto &I : Children)
489 ScopeDIE.addChild(std::move(I));
491 return ObjectPointer;
494 void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
495 LexicalScope *Scope) {
496 assert(Scope && Scope->getScopeNode());
497 assert(Scope->isAbstractScope());
498 assert(!Scope->getInlinedAt());
500 DISubprogram SP(Scope->getScopeNode());
502 ProcessedSPNodes.insert(SP);
504 DIE *&AbsDef = AbstractSPDies[SP];
508 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
509 // was inlined from another compile unit.
510 DwarfCompileUnit &SPCU = *SPMap[SP];
513 // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
514 // the important distinction that the DIDescriptor is not associated with the
515 // DIE (since the DIDescriptor will be associated with the concrete DIE, if
516 // any). It could be refactored to some common utility function.
517 if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
518 ContextDIE = &SPCU.getUnitDie();
519 SPCU.getOrCreateSubprogramDIE(SPDecl);
521 ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
523 // Passing null as the associated DIDescriptor because the abstract definition
524 // shouldn't be found by lookup.
525 AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
527 SPCU.applySubprogramAttributesToDefinition(SP, *AbsDef);
529 if (TheCU.getCUNode().getEmissionKind() != DIBuilder::LineTablesOnly)
530 SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
531 if (DIE *ObjectPointer = createAndAddScopeChildren(SPCU, Scope, *AbsDef))
532 SPCU.addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
535 void DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
536 LexicalScope *Scope) {
537 assert(Scope && Scope->getScopeNode());
538 assert(!Scope->getInlinedAt());
539 assert(!Scope->isAbstractScope());
540 DISubprogram Sub(Scope->getScopeNode());
542 assert(Sub.isSubprogram());
544 ProcessedSPNodes.insert(Sub);
546 DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub);
548 // Collect arguments for current function.
549 assert(LScopes.isCurrentFunctionScope(Scope));
550 DIE *ObjectPointer = nullptr;
551 for (DbgVariable *ArgDV : CurrentFnArguments)
554 constructVariableDIE(TheCU, *ArgDV, *Scope, ObjectPointer));
556 // If this is a variadic function, add an unspecified parameter.
557 DITypeArray FnArgs = Sub.getType().getTypeArray();
558 // If we have a single element of null, it is a function that returns void.
559 // If we have more than one elements and the last one is null, it is a
560 // variadic function.
561 if (FnArgs.getNumElements() > 1 &&
562 !FnArgs.getElement(FnArgs.getNumElements() - 1))
563 ScopeDIE.addChild(make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
565 // Collect lexical scope children first.
566 // ObjectPointer might be a local (non-argument) local variable if it's a
567 // block's synthetic this pointer.
568 if (DIE *BlockObjPtr = createAndAddScopeChildren(TheCU, Scope, ScopeDIE)) {
569 assert(!ObjectPointer && "multiple object pointers can't be described");
570 ObjectPointer = BlockObjPtr;
574 TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
577 // Construct a DIE for this scope.
578 void DwarfDebug::constructScopeDIE(
579 DwarfCompileUnit &TheCU, LexicalScope *Scope,
580 SmallVectorImpl<std::unique_ptr<DIE>> &FinalChildren) {
581 if (!Scope || !Scope->getScopeNode())
584 DIScope DS(Scope->getScopeNode());
586 assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
587 "Only handle inlined subprograms here, use "
588 "constructSubprogramScopeDIE for non-inlined "
591 SmallVector<std::unique_ptr<DIE>, 8> Children;
593 // We try to create the scope DIE first, then the children DIEs. This will
594 // avoid creating un-used children then removing them later when we find out
595 // the scope DIE is null.
596 std::unique_ptr<DIE> ScopeDIE;
597 if (Scope->getParent() && DS.isSubprogram()) {
598 ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
601 // We create children when the scope DIE is not null.
602 createScopeChildrenDIE(TheCU, Scope, Children);
604 // Early exit when we know the scope DIE is going to be null.
605 if (isLexicalScopeDIENull(Scope))
608 unsigned ChildScopeCount;
610 // We create children here when we know the scope DIE is not going to be
611 // null and the children will be added to the scope DIE.
612 createScopeChildrenDIE(TheCU, Scope, Children, &ChildScopeCount);
614 // There is no need to emit empty lexical block DIE.
615 std::pair<ImportedEntityMap::const_iterator,
616 ImportedEntityMap::const_iterator> Range =
617 std::equal_range(ScopesWithImportedEntities.begin(),
618 ScopesWithImportedEntities.end(),
619 std::pair<const MDNode *, const MDNode *>(DS, nullptr),
621 for (ImportedEntityMap::const_iterator i = Range.first; i != Range.second;
624 constructImportedEntityDIE(TheCU, DIImportedEntity(i->second)));
625 // If there are only other scopes as children, put them directly in the
626 // parent instead, as this scope would serve no purpose.
627 if (Children.size() == ChildScopeCount) {
628 FinalChildren.insert(FinalChildren.end(),
629 std::make_move_iterator(Children.begin()),
630 std::make_move_iterator(Children.end()));
633 ScopeDIE = constructLexicalScopeDIE(TheCU, Scope);
634 assert(ScopeDIE && "Scope DIE should not be null.");
638 for (auto &I : Children)
639 ScopeDIE->addChild(std::move(I));
641 FinalChildren.push_back(std::move(ScopeDIE));
644 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
645 if (!GenerateGnuPubSections)
648 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
651 // Create new DwarfCompileUnit for the given metadata node with tag
652 // DW_TAG_compile_unit.
653 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
654 StringRef FN = DIUnit.getFilename();
655 CompilationDir = DIUnit.getDirectory();
657 auto OwnedUnit = make_unique<DwarfCompileUnit>(
658 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
659 DwarfCompileUnit &NewCU = *OwnedUnit;
660 DIE &Die = NewCU.getUnitDie();
661 InfoHolder.addUnit(std::move(OwnedUnit));
663 // LTO with assembly output shares a single line table amongst multiple CUs.
664 // To avoid the compilation directory being ambiguous, let the line table
665 // explicitly describe the directory of all files, never relying on the
666 // compilation directory.
667 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
668 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
669 NewCU.getUniqueID(), CompilationDir);
671 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
672 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
673 DIUnit.getLanguage());
674 NewCU.addString(Die, dwarf::DW_AT_name, FN);
676 if (!useSplitDwarf()) {
677 NewCU.initStmtList(DwarfLineSectionSym);
679 // If we're using split dwarf the compilation dir is going to be in the
680 // skeleton CU and so we don't need to duplicate it here.
681 if (!CompilationDir.empty())
682 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
684 addGnuPubAttributes(NewCU, Die);
687 if (DIUnit.isOptimized())
688 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
690 StringRef Flags = DIUnit.getFlags();
692 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
694 if (unsigned RVer = DIUnit.getRunTimeVersion())
695 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
696 dwarf::DW_FORM_data1, RVer);
701 if (useSplitDwarf()) {
702 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
703 DwarfInfoDWOSectionSym);
704 NewCU.setSkeleton(constructSkeletonCU(NewCU));
706 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
707 DwarfInfoSectionSym);
709 CUMap.insert(std::make_pair(DIUnit, &NewCU));
710 CUDieMap.insert(std::make_pair(&Die, &NewCU));
714 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
716 DIImportedEntity Module(N);
717 assert(Module.Verify());
718 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
719 D->addChild(constructImportedEntityDIE(TheCU, Module));
723 DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
724 const DIImportedEntity &Module) {
725 assert(Module.Verify() &&
726 "Use one of the MDNode * overloads to handle invalid metadata");
727 std::unique_ptr<DIE> IMDie = make_unique<DIE>((dwarf::Tag)Module.getTag());
728 TheCU.insertDIE(Module, IMDie.get());
730 DIDescriptor Entity = resolve(Module.getEntity());
731 if (Entity.isNameSpace())
732 EntityDie = TheCU.getOrCreateNameSpace(DINameSpace(Entity));
733 else if (Entity.isSubprogram())
734 EntityDie = TheCU.getOrCreateSubprogramDIE(DISubprogram(Entity));
735 else if (Entity.isType())
736 EntityDie = TheCU.getOrCreateTypeDIE(DIType(Entity));
738 EntityDie = TheCU.getDIE(Entity);
740 TheCU.addSourceLine(*IMDie, Module.getLineNumber(),
741 Module.getContext().getFilename(),
742 Module.getContext().getDirectory());
743 TheCU.addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
744 StringRef Name = Module.getName();
746 TheCU.addString(*IMDie, dwarf::DW_AT_name, Name);
751 // Emit all Dwarf sections that should come prior to the content. Create
752 // global DIEs and emit initial debug info sections. This is invoked by
753 // the target AsmPrinter.
754 void DwarfDebug::beginModule() {
755 if (DisableDebugInfoPrinting)
758 const Module *M = MMI->getModule();
760 FunctionDIs = makeSubprogramMap(*M);
762 // If module has named metadata anchors then use them, otherwise scan the
763 // module using debug info finder to collect debug info.
764 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
767 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
769 // Emit initial sections so we can reference labels later.
772 SingleCU = CU_Nodes->getNumOperands() == 1;
774 for (MDNode *N : CU_Nodes->operands()) {
775 DICompileUnit CUNode(N);
776 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
777 DIArray ImportedEntities = CUNode.getImportedEntities();
778 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
779 ScopesWithImportedEntities.push_back(std::make_pair(
780 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
781 ImportedEntities.getElement(i)));
782 std::sort(ScopesWithImportedEntities.begin(),
783 ScopesWithImportedEntities.end(), less_first());
784 DIArray GVs = CUNode.getGlobalVariables();
785 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
786 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
787 DIArray SPs = CUNode.getSubprograms();
788 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
789 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
790 DIArray EnumTypes = CUNode.getEnumTypes();
791 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
792 DIType Ty(EnumTypes.getElement(i));
793 // The enum types array by design contains pointers to
794 // MDNodes rather than DIRefs. Unique them here.
795 DIType UniqueTy(resolve(Ty.getRef()));
796 CU.getOrCreateTypeDIE(UniqueTy);
798 DIArray RetainedTypes = CUNode.getRetainedTypes();
799 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
800 DIType Ty(RetainedTypes.getElement(i));
801 // The retained types array by design contains pointers to
802 // MDNodes rather than DIRefs. Unique them here.
803 DIType UniqueTy(resolve(Ty.getRef()));
804 CU.getOrCreateTypeDIE(UniqueTy);
806 // Emit imported_modules last so that the relevant context is already
808 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
809 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
812 // Tell MMI that we have debug info.
813 MMI->setDebugInfoAvailability(true);
815 // Prime section data.
816 SectionMap[Asm->getObjFileLowering().getTextSection()];
819 void DwarfDebug::finishVariableDefinitions() {
820 for (const auto &Var : ConcreteVariables) {
821 DIE *VariableDie = Var->getDIE();
823 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
824 // in the ConcreteVariables list, rather than looking it up again here.
825 // DIE::getUnit isn't simple - it walks parent pointers, etc.
826 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
828 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
829 if (AbsVar && AbsVar->getDIE()) {
830 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
833 Unit->applyVariableAttributes(*Var, *VariableDie);
837 void DwarfDebug::finishSubprogramDefinitions() {
838 const Module *M = MMI->getModule();
840 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
841 for (MDNode *N : CU_Nodes->operands()) {
842 DICompileUnit TheCU(N);
843 // Construct subprogram DIE and add variables DIEs.
844 DwarfCompileUnit *SPCU =
845 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
846 DIArray Subprograms = TheCU.getSubprograms();
847 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
848 DISubprogram SP(Subprograms.getElement(i));
849 // Perhaps the subprogram is in another CU (such as due to comdat
850 // folding, etc), in which case ignore it here.
851 if (SPMap[SP] != SPCU)
853 DIE *D = SPCU->getDIE(SP);
854 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
856 // If this subprogram has an abstract definition, reference that
857 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
859 if (!D && TheCU.getEmissionKind() != DIBuilder::LineTablesOnly)
860 // Lazily construct the subprogram if we didn't see either concrete or
861 // inlined versions during codegen. (except in -gmlt ^ where we want
862 // to omit these entirely)
863 D = SPCU->getOrCreateSubprogramDIE(SP);
865 // And attach the attributes
866 SPCU->applySubprogramAttributesToDefinition(SP, *D);
873 // Collect info for variables that were optimized out.
874 void DwarfDebug::collectDeadVariables() {
875 const Module *M = MMI->getModule();
877 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
878 for (MDNode *N : CU_Nodes->operands()) {
879 DICompileUnit TheCU(N);
880 // Construct subprogram DIE and add variables DIEs.
881 DwarfCompileUnit *SPCU =
882 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
883 assert(SPCU && "Unable to find Compile Unit!");
884 DIArray Subprograms = TheCU.getSubprograms();
885 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
886 DISubprogram SP(Subprograms.getElement(i));
887 if (ProcessedSPNodes.count(SP) != 0)
889 assert(SP.isSubprogram() &&
890 "CU's subprogram list contains a non-subprogram");
891 assert(SP.isDefinition() &&
892 "CU's subprogram list contains a subprogram declaration");
893 DIArray Variables = SP.getVariables();
894 if (Variables.getNumElements() == 0)
897 DIE *SPDIE = AbstractSPDies.lookup(SP);
899 SPDIE = SPCU->getDIE(SP);
901 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
902 DIVariable DV(Variables.getElement(vi));
903 assert(DV.isVariable());
904 DbgVariable NewVar(DV, DIExpression(nullptr), this);
905 auto VariableDie = SPCU->constructVariableDIE(NewVar);
906 SPCU->applyVariableAttributes(NewVar, *VariableDie);
907 SPDIE->addChild(std::move(VariableDie));
914 void DwarfDebug::finalizeModuleInfo() {
915 finishSubprogramDefinitions();
917 finishVariableDefinitions();
919 // Collect info for variables that were optimized out.
920 collectDeadVariables();
922 // Handle anything that needs to be done on a per-unit basis after
923 // all other generation.
924 for (const auto &TheU : getUnits()) {
925 // Emit DW_AT_containing_type attribute to connect types with their
926 // vtable holding type.
927 TheU->constructContainingTypeDIEs();
929 // Add CU specific attributes if we need to add any.
930 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
931 // If we're splitting the dwarf out now that we've got the entire
932 // CU then add the dwo id to it.
933 DwarfCompileUnit *SkCU =
934 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
935 if (useSplitDwarf()) {
936 // Emit a unique identifier for this CU.
937 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
938 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
939 dwarf::DW_FORM_data8, ID);
940 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
941 dwarf::DW_FORM_data8, ID);
943 // We don't keep track of which addresses are used in which CU so this
944 // is a bit pessimistic under LTO.
945 if (!AddrPool.isEmpty())
946 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
947 dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
948 DwarfAddrSectionSym);
949 if (!TheU->getRangeLists().empty())
950 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
951 dwarf::DW_AT_GNU_ranges_base,
952 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
955 // If we have code split among multiple sections or non-contiguous
956 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
957 // remain in the .o file, otherwise add a DW_AT_low_pc.
958 // FIXME: We should use ranges allow reordering of code ala
959 // .subsections_via_symbols in mach-o. This would mean turning on
960 // ranges for all subprogram DIEs for mach-o.
961 DwarfCompileUnit &U =
962 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
963 unsigned NumRanges = TheU->getRanges().size();
966 addSectionLabel(*Asm, U, U.getUnitDie(), dwarf::DW_AT_ranges,
967 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
968 DwarfDebugRangeSectionSym);
970 // A DW_AT_low_pc attribute may also be specified in combination with
971 // DW_AT_ranges to specify the default base address for use in
972 // location lists (see Section 2.6.2) and range lists (see Section
974 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
977 RangeSpan &Range = TheU->getRanges().back();
978 attachLowHighPC(U, U.getUnitDie(), Range.getStart(), Range.getEnd());
984 // Compute DIE offsets and sizes.
985 InfoHolder.computeSizeAndOffsets();
987 SkeletonHolder.computeSizeAndOffsets();
990 void DwarfDebug::endSections() {
991 // Filter labels by section.
992 for (const SymbolCU &SCU : ArangeLabels) {
993 if (SCU.Sym->isInSection()) {
994 // Make a note of this symbol and it's section.
995 const MCSection *Section = &SCU.Sym->getSection();
996 if (!Section->getKind().isMetadata())
997 SectionMap[Section].push_back(SCU);
999 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1000 // appear in the output. This sucks as we rely on sections to build
1001 // arange spans. We can do it without, but it's icky.
1002 SectionMap[nullptr].push_back(SCU);
1006 // Build a list of sections used.
1007 std::vector<const MCSection *> Sections;
1008 for (const auto &it : SectionMap) {
1009 const MCSection *Section = it.first;
1010 Sections.push_back(Section);
1013 // Sort the sections into order.
1014 // This is only done to ensure consistent output order across different runs.
1015 std::sort(Sections.begin(), Sections.end(), SectionSort);
1017 // Add terminating symbols for each section.
1018 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
1019 const MCSection *Section = Sections[ID];
1020 MCSymbol *Sym = nullptr;
1023 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1024 // if we know the section name up-front. For user-created sections, the
1025 // resulting label may not be valid to use as a label. (section names can
1026 // use a greater set of characters on some systems)
1027 Sym = Asm->GetTempSymbol("debug_end", ID);
1028 Asm->OutStreamer.SwitchSection(Section);
1029 Asm->OutStreamer.EmitLabel(Sym);
1032 // Insert a final terminator.
1033 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1037 // Emit all Dwarf sections that should come after the content.
1038 void DwarfDebug::endModule() {
1039 assert(CurFn == nullptr);
1040 assert(CurMI == nullptr);
1045 // End any existing sections.
1046 // TODO: Does this need to happen?
1049 // Finalize the debug info for the module.
1050 finalizeModuleInfo();
1054 // Emit all the DIEs into a debug info section.
1057 // Corresponding abbreviations into a abbrev section.
1058 emitAbbreviations();
1060 // Emit info into a debug aranges section.
1061 if (GenerateARangeSection)
1064 // Emit info into a debug ranges section.
1067 if (useSplitDwarf()) {
1070 emitDebugAbbrevDWO();
1073 // Emit DWO addresses.
1074 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
1076 // Emit info into a debug loc section.
1079 // Emit info into the dwarf accelerator table sections.
1080 if (useDwarfAccelTables()) {
1083 emitAccelNamespaces();
1087 // Emit the pubnames and pubtypes sections if requested.
1088 if (HasDwarfPubSections) {
1089 emitDebugPubNames(GenerateGnuPubSections);
1090 emitDebugPubTypes(GenerateGnuPubSections);
1095 AbstractVariables.clear();
1097 // Reset these for the next Module if we have one.
1101 // Find abstract variable, if any, associated with Var.
1102 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
1103 DIVariable &Cleansed) {
1104 LLVMContext &Ctx = DV->getContext();
1105 // More then one inlined variable corresponds to one abstract variable.
1106 // FIXME: This duplication of variables when inlining should probably be
1107 // removed. It's done to allow each DIVariable to describe its location
1108 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
1109 // make it accurate then remove this duplication/cleansing stuff.
1110 Cleansed = cleanseInlinedVariable(DV, Ctx);
1111 auto I = AbstractVariables.find(Cleansed);
1112 if (I != AbstractVariables.end())
1113 return I->second.get();
1117 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
1118 DIVariable Cleansed;
1119 return getExistingAbstractVariable(DV, Cleansed);
1122 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
1123 LexicalScope *Scope) {
1124 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
1125 addScopeVariable(Scope, AbsDbgVariable.get());
1126 AbstractVariables[Var] = std::move(AbsDbgVariable);
1129 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
1130 const MDNode *ScopeNode) {
1131 DIVariable Cleansed = DV;
1132 if (getExistingAbstractVariable(DV, Cleansed))
1135 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
1139 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
1140 const MDNode *ScopeNode) {
1141 DIVariable Cleansed = DV;
1142 if (getExistingAbstractVariable(DV, Cleansed))
1145 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
1146 createAbstractVariable(Cleansed, Scope);
1149 // If Var is a current function argument then add it to CurrentFnArguments list.
1150 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
1151 if (!LScopes.isCurrentFunctionScope(Scope))
1153 DIVariable DV = Var->getVariable();
1154 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
1156 unsigned ArgNo = DV.getArgNumber();
1160 size_t Size = CurrentFnArguments.size();
1162 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
1163 // llvm::Function argument size is not good indicator of how many
1164 // arguments does the function have at source level.
1166 CurrentFnArguments.resize(ArgNo * 2);
1167 assert(!CurrentFnArguments[ArgNo - 1]);
1168 CurrentFnArguments[ArgNo - 1] = Var;
1172 // Collect variable information from side table maintained by MMI.
1173 void DwarfDebug::collectVariableInfoFromMMITable(
1174 SmallPtrSetImpl<const MDNode *> &Processed) {
1175 for (const auto &VI : MMI->getVariableDbgInfo()) {
1178 Processed.insert(VI.Var);
1179 DIVariable DV(VI.Var);
1180 DIExpression Expr(VI.Expr);
1181 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
1183 // If variable scope is not found then skip this variable.
1187 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1188 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
1189 DbgVariable *RegVar = ConcreteVariables.back().get();
1190 RegVar->setFrameIndex(VI.Slot);
1191 addScopeVariable(Scope, RegVar);
1195 // Get .debug_loc entry for the instruction range starting at MI.
1196 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
1197 const MDNode *Expr = MI->getDebugExpression();
1198 const MDNode *Var = MI->getDebugVariable();
1200 assert(MI->getNumOperands() == 4);
1201 if (MI->getOperand(0).isReg()) {
1202 MachineLocation MLoc;
1203 // If the second operand is an immediate, this is a
1204 // register-indirect address.
1205 if (!MI->getOperand(1).isImm())
1206 MLoc.set(MI->getOperand(0).getReg());
1208 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
1209 return DebugLocEntry::Value(Var, Expr, MLoc);
1211 if (MI->getOperand(0).isImm())
1212 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
1213 if (MI->getOperand(0).isFPImm())
1214 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
1215 if (MI->getOperand(0).isCImm())
1216 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
1218 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
1221 /// Determine whether two variable pieces overlap.
1222 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
1223 if (!P1.isVariablePiece() || !P2.isVariablePiece())
1225 unsigned l1 = P1.getPieceOffset();
1226 unsigned l2 = P2.getPieceOffset();
1227 unsigned r1 = l1 + P1.getPieceSize();
1228 unsigned r2 = l2 + P2.getPieceSize();
1229 // True where [l1,r1[ and [r1,r2[ overlap.
1230 return (l1 < r2) && (l2 < r1);
1233 /// Build the location list for all DBG_VALUEs in the function that
1234 /// describe the same variable. If the ranges of several independent
1235 /// pieces of the same variable overlap partially, split them up and
1236 /// combine the ranges. The resulting DebugLocEntries are will have
1237 /// strict monotonically increasing begin addresses and will never
1242 // Ranges History [var, loc, piece ofs size]
1243 // 0 | [x, (reg0, piece 0, 32)]
1244 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
1246 // 3 | [clobber reg0]
1247 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
1251 // [0-1] [x, (reg0, piece 0, 32)]
1252 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
1253 // [3-4] [x, (reg1, piece 32, 32)]
1254 // [4- ] [x, (mem, piece 0, 64)]
1256 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
1257 const DbgValueHistoryMap::InstrRanges &Ranges) {
1258 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
1260 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1261 const MachineInstr *Begin = I->first;
1262 const MachineInstr *End = I->second;
1263 assert(Begin->isDebugValue() && "Invalid History entry");
1265 // Check if a variable is inaccessible in this range.
1266 if (Begin->getNumOperands() > 1 &&
1267 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
1272 // If this piece overlaps with any open ranges, truncate them.
1273 DIExpression DIExpr = Begin->getDebugExpression();
1274 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
1275 [&](DebugLocEntry::Value R) {
1276 return piecesOverlap(DIExpr, R.getExpression());
1278 OpenRanges.erase(Last, OpenRanges.end());
1280 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
1281 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
1283 const MCSymbol *EndLabel;
1285 EndLabel = getLabelAfterInsn(End);
1286 else if (std::next(I) == Ranges.end())
1287 EndLabel = FunctionEndSym;
1289 EndLabel = getLabelBeforeInsn(std::next(I)->first);
1290 assert(EndLabel && "Forgot label after instruction ending a range!");
1292 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
1294 auto Value = getDebugLocValue(Begin);
1295 DebugLocEntry Loc(StartLabel, EndLabel, Value);
1296 bool couldMerge = false;
1298 // If this is a piece, it may belong to the current DebugLocEntry.
1299 if (DIExpr.isVariablePiece()) {
1300 // Add this value to the list of open ranges.
1301 OpenRanges.push_back(Value);
1303 // Attempt to add the piece to the last entry.
1304 if (!DebugLoc.empty())
1305 if (DebugLoc.back().MergeValues(Loc))
1310 // Need to add a new DebugLocEntry. Add all values from still
1311 // valid non-overlapping pieces.
1312 if (OpenRanges.size())
1313 Loc.addValues(OpenRanges);
1315 DebugLoc.push_back(std::move(Loc));
1318 // Attempt to coalesce the ranges of two otherwise identical
1320 auto CurEntry = DebugLoc.rbegin();
1321 auto PrevEntry = std::next(CurEntry);
1322 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
1323 DebugLoc.pop_back();
1326 dbgs() << CurEntry->getValues().size() << " Values:\n";
1327 for (auto Value : CurEntry->getValues()) {
1328 Value.getVariable()->dump();
1329 Value.getExpression()->dump();
1331 dbgs() << "-----\n";
1337 // Find variables for each lexical scope.
1339 DwarfDebug::collectVariableInfo(SmallPtrSetImpl<const MDNode *> &Processed) {
1340 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1341 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1343 // Grab the variable info that was squirreled away in the MMI side-table.
1344 collectVariableInfoFromMMITable(Processed);
1346 for (const auto &I : DbgValues) {
1347 DIVariable DV(I.first);
1348 if (Processed.count(DV))
1351 // Instruction ranges, specifying where DV is accessible.
1352 const auto &Ranges = I.second;
1356 LexicalScope *Scope = nullptr;
1357 if (MDNode *IA = DV.getInlinedAt()) {
1358 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1359 Scope = LScopes.findInlinedScope(DebugLoc::get(
1360 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1362 Scope = LScopes.findLexicalScope(DV.getContext());
1363 // If variable scope is not found then skip this variable.
1367 Processed.insert(DV);
1368 const MachineInstr *MInsn = Ranges.front().first;
1369 assert(MInsn->isDebugValue() && "History must begin with debug value");
1370 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1371 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
1372 DbgVariable *RegVar = ConcreteVariables.back().get();
1373 addScopeVariable(Scope, RegVar);
1375 // Check if the first DBG_VALUE is valid for the rest of the function.
1376 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1379 // Handle multiple DBG_VALUE instructions describing one variable.
1380 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1382 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1383 DebugLocList &LocList = DotDebugLocEntries.back();
1386 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1388 // Build the location list for this variable.
1389 buildLocationList(LocList.List, Ranges);
1392 // Collect info for variables that were optimized out.
1393 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1394 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1395 DIVariable DV(Variables.getElement(i));
1396 assert(DV.isVariable());
1397 if (!Processed.insert(DV))
1399 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1400 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1401 DIExpression NoExpr;
1402 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
1403 addScopeVariable(Scope, ConcreteVariables.back().get());
1408 // Return Label preceding the instruction.
1409 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1410 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1411 assert(Label && "Didn't insert label before instruction");
1415 // Return Label immediately following the instruction.
1416 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1417 return LabelsAfterInsn.lookup(MI);
1420 // Process beginning of an instruction.
1421 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1422 assert(CurMI == nullptr);
1424 // Check if source location changes, but ignore DBG_VALUE locations.
1425 if (!MI->isDebugValue()) {
1426 DebugLoc DL = MI->getDebugLoc();
1427 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1430 if (DL == PrologEndLoc) {
1431 Flags |= DWARF2_FLAG_PROLOGUE_END;
1432 PrologEndLoc = DebugLoc();
1434 if (PrologEndLoc.isUnknown())
1435 Flags |= DWARF2_FLAG_IS_STMT;
1437 if (!DL.isUnknown()) {
1438 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1439 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1441 recordSourceLine(0, 0, nullptr, 0);
1445 // Insert labels where requested.
1446 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1447 LabelsBeforeInsn.find(MI);
1450 if (I == LabelsBeforeInsn.end())
1453 // Label already assigned.
1458 PrevLabel = MMI->getContext().CreateTempSymbol();
1459 Asm->OutStreamer.EmitLabel(PrevLabel);
1461 I->second = PrevLabel;
1464 // Process end of an instruction.
1465 void DwarfDebug::endInstruction() {
1466 assert(CurMI != nullptr);
1467 // Don't create a new label after DBG_VALUE instructions.
1468 // They don't generate code.
1469 if (!CurMI->isDebugValue())
1470 PrevLabel = nullptr;
1472 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1473 LabelsAfterInsn.find(CurMI);
1477 if (I == LabelsAfterInsn.end())
1480 // Label already assigned.
1484 // We need a label after this instruction.
1486 PrevLabel = MMI->getContext().CreateTempSymbol();
1487 Asm->OutStreamer.EmitLabel(PrevLabel);
1489 I->second = PrevLabel;
1492 // Each LexicalScope has first instruction and last instruction to mark
1493 // beginning and end of a scope respectively. Create an inverse map that list
1494 // scopes starts (and ends) with an instruction. One instruction may start (or
1495 // end) multiple scopes. Ignore scopes that are not reachable.
1496 void DwarfDebug::identifyScopeMarkers() {
1497 SmallVector<LexicalScope *, 4> WorkList;
1498 WorkList.push_back(LScopes.getCurrentFunctionScope());
1499 while (!WorkList.empty()) {
1500 LexicalScope *S = WorkList.pop_back_val();
1502 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1503 if (!Children.empty())
1504 WorkList.append(Children.begin(), Children.end());
1506 if (S->isAbstractScope())
1509 for (const InsnRange &R : S->getRanges()) {
1510 assert(R.first && "InsnRange does not have first instruction!");
1511 assert(R.second && "InsnRange does not have second instruction!");
1512 requestLabelBeforeInsn(R.first);
1513 requestLabelAfterInsn(R.second);
1518 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1519 // First known non-DBG_VALUE and non-frame setup location marks
1520 // the beginning of the function body.
1521 for (const auto &MBB : *MF)
1522 for (const auto &MI : MBB)
1523 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1524 !MI.getDebugLoc().isUnknown())
1525 return MI.getDebugLoc();
1529 // Gather pre-function debug information. Assumes being called immediately
1530 // after the function entry point has been emitted.
1531 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1534 // If there's no debug info for the function we're not going to do anything.
1535 if (!MMI->hasDebugInfo())
1538 auto DI = FunctionDIs.find(MF->getFunction());
1539 if (DI == FunctionDIs.end())
1542 // Grab the lexical scopes for the function, if we don't have any of those
1543 // then we're not going to be able to do anything.
1544 LScopes.initialize(*MF);
1545 if (LScopes.empty())
1548 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1550 // Make sure that each lexical scope will have a begin/end label.
1551 identifyScopeMarkers();
1553 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1554 // belongs to so that we add to the correct per-cu line table in the
1556 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1557 // FnScope->getScopeNode() and DI->second should represent the same function,
1558 // though they may not be the same MDNode due to inline functions merged in
1559 // LTO where the debug info metadata still differs (either due to distinct
1560 // written differences - two versions of a linkonce_odr function
1561 // written/copied into two separate files, or some sub-optimal metadata that
1562 // isn't structurally identical (see: file path/name info from clang, which
1563 // includes the directory of the cpp file being built, even when the file name
1564 // is absolute (such as an <> lookup header)))
1565 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1566 assert(TheCU && "Unable to find compile unit!");
1567 if (Asm->OutStreamer.hasRawTextSupport())
1568 // Use a single line table if we are generating assembly.
1569 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1571 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1573 // Emit a label for the function so that we have a beginning address.
1574 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1575 // Assumes in correct section after the entry point.
1576 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1578 // Calculate history for local variables.
1579 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1582 // Request labels for the full history.
1583 for (const auto &I : DbgValues) {
1584 const auto &Ranges = I.second;
1588 // The first mention of a function argument gets the FunctionBeginSym
1589 // label, so arguments are visible when breaking at function entry.
1590 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1591 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1592 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1593 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1594 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1595 // Mark all non-overlapping initial pieces.
1596 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1597 DIExpression Piece = I->first->getDebugExpression();
1598 if (std::all_of(Ranges.begin(), I,
1599 [&](DbgValueHistoryMap::InstrRange Pred) {
1600 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1602 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1609 for (const auto &Range : Ranges) {
1610 requestLabelBeforeInsn(Range.first);
1612 requestLabelAfterInsn(Range.second);
1616 PrevInstLoc = DebugLoc();
1617 PrevLabel = FunctionBeginSym;
1619 // Record beginning of function.
1620 PrologEndLoc = findPrologueEndLoc(MF);
1621 if (!PrologEndLoc.isUnknown()) {
1622 DebugLoc FnStartDL =
1623 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1625 FnStartDL.getLine(), FnStartDL.getCol(),
1626 FnStartDL.getScope(MF->getFunction()->getContext()),
1627 // We'd like to list the prologue as "not statements" but GDB behaves
1628 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1629 DWARF2_FLAG_IS_STMT);
1633 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1634 if (addCurrentFnArgument(Var, LS))
1636 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1637 DIVariable DV = Var->getVariable();
1638 // Variables with positive arg numbers are parameters.
1639 if (unsigned ArgNum = DV.getArgNumber()) {
1640 // Keep all parameters in order at the start of the variable list to ensure
1641 // function types are correct (no out-of-order parameters)
1643 // This could be improved by only doing it for optimized builds (unoptimized
1644 // builds have the right order to begin with), searching from the back (this
1645 // would catch the unoptimized case quickly), or doing a binary search
1646 // rather than linear search.
1647 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1648 while (I != Vars.end()) {
1649 unsigned CurNum = (*I)->getVariable().getArgNumber();
1650 // A local (non-parameter) variable has been found, insert immediately
1654 // A later indexed parameter has been found, insert immediately before it.
1655 if (CurNum > ArgNum)
1659 Vars.insert(I, Var);
1663 Vars.push_back(Var);
1666 // Gather and emit post-function debug information.
1667 void DwarfDebug::endFunction(const MachineFunction *MF) {
1668 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1669 // though the beginFunction may not be called at all.
1670 // We should handle both cases.
1674 assert(CurFn == MF);
1675 assert(CurFn != nullptr);
1677 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1678 !FunctionDIs.count(MF->getFunction())) {
1679 // If we don't have a lexical scope for this function then there will
1680 // be a hole in the range information. Keep note of this by setting the
1681 // previously used section to nullptr.
1687 // Define end label for subprogram.
1688 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1689 // Assumes in correct section after the entry point.
1690 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1692 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1693 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1695 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1696 collectVariableInfo(ProcessedVars);
1698 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1699 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1701 // Add the range of this function to the list of ranges for the CU.
1702 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1704 // Under -gmlt, skip building the subprogram if there are no inlined
1705 // subroutines inside it.
1706 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1707 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1708 assert(ScopeVariables.empty());
1709 assert(CurrentFnArguments.empty());
1710 assert(DbgValues.empty());
1711 assert(AbstractVariables.empty());
1712 LabelsBeforeInsn.clear();
1713 LabelsAfterInsn.clear();
1714 PrevLabel = nullptr;
1719 // Construct abstract scopes.
1720 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1721 DISubprogram SP(AScope->getScopeNode());
1722 assert(SP.isSubprogram());
1723 // Collect info for variables that were optimized out.
1724 DIArray Variables = SP.getVariables();
1725 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1726 DIVariable DV(Variables.getElement(i));
1727 assert(DV && DV.isVariable());
1728 if (!ProcessedVars.insert(DV))
1730 ensureAbstractVariableIsCreated(DV, DV.getContext());
1732 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1735 constructSubprogramScopeDIE(TheCU, FnScope);
1738 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1739 // DbgVariables except those that are also in AbstractVariables (since they
1740 // can be used cross-function)
1741 ScopeVariables.clear();
1742 CurrentFnArguments.clear();
1744 LabelsBeforeInsn.clear();
1745 LabelsAfterInsn.clear();
1746 PrevLabel = nullptr;
1750 // Register a source line with debug info. Returns the unique label that was
1751 // emitted and which provides correspondence to the source line list.
1752 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1757 unsigned Discriminator = 0;
1758 if (DIScope Scope = DIScope(S)) {
1759 assert(Scope.isScope());
1760 Fn = Scope.getFilename();
1761 Dir = Scope.getDirectory();
1762 if (Scope.isLexicalBlockFile())
1763 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1765 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1766 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1767 .getOrCreateSourceID(Fn, Dir);
1769 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1773 //===----------------------------------------------------------------------===//
1775 //===----------------------------------------------------------------------===//
1777 // Emit initial Dwarf sections with a label at the start of each one.
1778 void DwarfDebug::emitSectionLabels() {
1779 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1781 // Dwarf sections base addresses.
1782 DwarfInfoSectionSym =
1783 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1784 if (useSplitDwarf()) {
1785 DwarfInfoDWOSectionSym =
1786 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1787 DwarfTypesDWOSectionSym =
1788 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1790 DwarfAbbrevSectionSym =
1791 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1792 if (useSplitDwarf())
1793 DwarfAbbrevDWOSectionSym = emitSectionSym(
1794 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1795 if (GenerateARangeSection)
1796 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1798 DwarfLineSectionSym =
1799 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1800 if (GenerateGnuPubSections) {
1801 DwarfGnuPubNamesSectionSym =
1802 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1803 DwarfGnuPubTypesSectionSym =
1804 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1805 } else if (HasDwarfPubSections) {
1806 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1807 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1810 DwarfStrSectionSym =
1811 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1812 if (useSplitDwarf()) {
1813 DwarfStrDWOSectionSym =
1814 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1815 DwarfAddrSectionSym =
1816 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1817 DwarfDebugLocSectionSym =
1818 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1820 DwarfDebugLocSectionSym =
1821 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1822 DwarfDebugRangeSectionSym =
1823 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1826 // Recursively emits a debug information entry.
1827 void DwarfDebug::emitDIE(DIE &Die) {
1828 // Get the abbreviation for this DIE.
1829 const DIEAbbrev &Abbrev = Die.getAbbrev();
1831 // Emit the code (index) for the abbreviation.
1832 if (Asm->isVerbose())
1833 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1834 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1835 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1836 dwarf::TagString(Abbrev.getTag()));
1837 Asm->EmitULEB128(Abbrev.getNumber());
1839 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1840 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1842 // Emit the DIE attribute values.
1843 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1844 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1845 dwarf::Form Form = AbbrevData[i].getForm();
1846 assert(Form && "Too many attributes for DIE (check abbreviation)");
1848 if (Asm->isVerbose()) {
1849 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1850 if (Attr == dwarf::DW_AT_accessibility)
1851 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1852 cast<DIEInteger>(Values[i])->getValue()));
1855 // Emit an attribute using the defined form.
1856 Values[i]->EmitValue(Asm, Form);
1859 // Emit the DIE children if any.
1860 if (Abbrev.hasChildren()) {
1861 for (auto &Child : Die.getChildren())
1864 Asm->OutStreamer.AddComment("End Of Children Mark");
1869 // Emit the debug info section.
1870 void DwarfDebug::emitDebugInfo() {
1871 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1873 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1876 // Emit the abbreviation section.
1877 void DwarfDebug::emitAbbreviations() {
1878 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1880 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1883 // Emit the last address of the section and the end of the line matrix.
1884 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1885 // Define last address of section.
1886 Asm->OutStreamer.AddComment("Extended Op");
1889 Asm->OutStreamer.AddComment("Op size");
1890 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1891 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1892 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1894 Asm->OutStreamer.AddComment("Section end label");
1896 Asm->OutStreamer.EmitSymbolValue(
1897 Asm->GetTempSymbol("section_end", SectionEnd),
1898 Asm->getDataLayout().getPointerSize());
1900 // Mark end of matrix.
1901 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1907 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1908 StringRef TableName, StringRef SymName) {
1909 Accel.FinalizeTable(Asm, TableName);
1910 Asm->OutStreamer.SwitchSection(Section);
1911 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1912 Asm->OutStreamer.EmitLabel(SectionBegin);
1914 // Emit the full data.
1915 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1918 // Emit visible names into a hashed accelerator table section.
1919 void DwarfDebug::emitAccelNames() {
1920 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1921 "Names", "names_begin");
1924 // Emit objective C classes and categories into a hashed accelerator table
1926 void DwarfDebug::emitAccelObjC() {
1927 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1928 "ObjC", "objc_begin");
1931 // Emit namespace dies into a hashed accelerator table.
1932 void DwarfDebug::emitAccelNamespaces() {
1933 emitAccel(AccelNamespace,
1934 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1935 "namespac", "namespac_begin");
1938 // Emit type dies into a hashed accelerator table.
1939 void DwarfDebug::emitAccelTypes() {
1940 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1941 "types", "types_begin");
1944 // Public name handling.
1945 // The format for the various pubnames:
1947 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1948 // for the DIE that is named.
1950 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1951 // into the CU and the index value is computed according to the type of value
1952 // for the DIE that is named.
1954 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1955 // it's the offset within the debug_info/debug_types dwo section, however, the
1956 // reference in the pubname header doesn't change.
1958 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1959 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1961 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1963 // We could have a specification DIE that has our most of our knowledge,
1964 // look for that now.
1965 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1967 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1968 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1969 Linkage = dwarf::GIEL_EXTERNAL;
1970 } else if (Die->findAttribute(dwarf::DW_AT_external))
1971 Linkage = dwarf::GIEL_EXTERNAL;
1973 switch (Die->getTag()) {
1974 case dwarf::DW_TAG_class_type:
1975 case dwarf::DW_TAG_structure_type:
1976 case dwarf::DW_TAG_union_type:
1977 case dwarf::DW_TAG_enumeration_type:
1978 return dwarf::PubIndexEntryDescriptor(
1979 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1980 ? dwarf::GIEL_STATIC
1981 : dwarf::GIEL_EXTERNAL);
1982 case dwarf::DW_TAG_typedef:
1983 case dwarf::DW_TAG_base_type:
1984 case dwarf::DW_TAG_subrange_type:
1985 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1986 case dwarf::DW_TAG_namespace:
1987 return dwarf::GIEK_TYPE;
1988 case dwarf::DW_TAG_subprogram:
1989 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1990 case dwarf::DW_TAG_constant:
1991 case dwarf::DW_TAG_variable:
1992 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1993 case dwarf::DW_TAG_enumerator:
1994 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1995 dwarf::GIEL_STATIC);
1997 return dwarf::GIEK_NONE;
2001 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
2003 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
2004 const MCSection *PSec =
2005 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
2006 : Asm->getObjFileLowering().getDwarfPubNamesSection();
2008 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
2011 void DwarfDebug::emitDebugPubSection(
2012 bool GnuStyle, const MCSection *PSec, StringRef Name,
2013 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
2014 for (const auto &NU : CUMap) {
2015 DwarfCompileUnit *TheU = NU.second;
2017 const auto &Globals = (TheU->*Accessor)();
2019 if (Globals.empty())
2022 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
2024 unsigned ID = TheU->getUniqueID();
2026 // Start the dwarf pubnames section.
2027 Asm->OutStreamer.SwitchSection(PSec);
2030 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
2031 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
2032 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
2033 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
2035 Asm->OutStreamer.EmitLabel(BeginLabel);
2037 Asm->OutStreamer.AddComment("DWARF Version");
2038 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
2040 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
2041 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
2043 Asm->OutStreamer.AddComment("Compilation Unit Length");
2044 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
2046 // Emit the pubnames for this compilation unit.
2047 for (const auto &GI : Globals) {
2048 const char *Name = GI.getKeyData();
2049 const DIE *Entity = GI.second;
2051 Asm->OutStreamer.AddComment("DIE offset");
2052 Asm->EmitInt32(Entity->getOffset());
2055 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
2056 Asm->OutStreamer.AddComment(
2057 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
2058 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
2059 Asm->EmitInt8(Desc.toBits());
2062 Asm->OutStreamer.AddComment("External Name");
2063 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
2066 Asm->OutStreamer.AddComment("End Mark");
2068 Asm->OutStreamer.EmitLabel(EndLabel);
2072 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
2073 const MCSection *PSec =
2074 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
2075 : Asm->getObjFileLowering().getDwarfPubTypesSection();
2077 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
2080 // Emit visible names into a debug str section.
2081 void DwarfDebug::emitDebugStr() {
2082 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
2083 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
2086 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
2087 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
2088 const DITypeIdentifierMap &Map,
2089 ArrayRef<DebugLocEntry::Value> Values) {
2090 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
2091 return P.isVariablePiece();
2092 }) && "all values are expected to be pieces");
2093 assert(std::is_sorted(Values.begin(), Values.end()) &&
2094 "pieces are expected to be sorted");
2096 unsigned Offset = 0;
2097 for (auto Piece : Values) {
2098 DIExpression Expr = Piece.getExpression();
2099 unsigned PieceOffset = Expr.getPieceOffset();
2100 unsigned PieceSize = Expr.getPieceSize();
2101 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
2102 if (Offset < PieceOffset) {
2103 // The DWARF spec seriously mandates pieces with no locations for gaps.
2104 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
2105 Offset += PieceOffset-Offset;
2108 Offset += PieceSize;
2110 const unsigned SizeOfByte = 8;
2112 DIVariable Var = Piece.getVariable();
2113 assert(!Var.isIndirect() && "indirect address for piece");
2114 unsigned VarSize = Var.getSizeInBits(Map);
2115 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
2116 && "piece is larger than or outside of variable");
2117 assert(PieceSize*SizeOfByte != VarSize
2118 && "piece covers entire variable");
2120 if (Piece.isLocation() && Piece.getLoc().isReg())
2121 Asm->EmitDwarfRegOpPiece(Streamer,
2123 PieceSize*SizeOfByte);
2125 emitDebugLocValue(Streamer, Piece);
2126 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
2132 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
2133 const DebugLocEntry &Entry) {
2134 const DebugLocEntry::Value Value = Entry.getValues()[0];
2135 if (Value.isVariablePiece())
2136 // Emit all pieces that belong to the same variable and range.
2137 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
2139 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
2140 emitDebugLocValue(Streamer, Value);
2143 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
2144 const DebugLocEntry::Value &Value) {
2145 DIVariable DV = Value.getVariable();
2147 if (Value.isInt()) {
2148 DIBasicType BTy(resolve(DV.getType()));
2149 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
2150 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
2151 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
2152 Streamer.EmitSLEB128(Value.getInt());
2154 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
2155 Streamer.EmitULEB128(Value.getInt());
2157 } else if (Value.isLocation()) {
2158 MachineLocation Loc = Value.getLoc();
2159 DIExpression Expr = Value.getExpression();
2162 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2164 // Complex address entry.
2165 unsigned N = Expr.getNumElements();
2167 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
2168 if (Loc.getOffset()) {
2170 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2171 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2172 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2173 Streamer.EmitSLEB128(Expr.getElement(1));
2175 // If first address element is OpPlus then emit
2176 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
2177 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
2178 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
2182 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2185 // Emit remaining complex address elements.
2186 for (; i < N; ++i) {
2187 uint64_t Element = Expr.getElement(i);
2188 if (Element == dwarf::DW_OP_plus) {
2189 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2190 Streamer.EmitULEB128(Expr.getElement(++i));
2191 } else if (Element == dwarf::DW_OP_deref) {
2193 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2194 } else if (Element == dwarf::DW_OP_piece) {
2196 // handled in emitDebugLocEntry.
2198 llvm_unreachable("unknown Opcode found in complex address");
2202 // else ... ignore constant fp. There is not any good way to
2203 // to represent them here in dwarf.
2207 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
2208 Asm->OutStreamer.AddComment("Loc expr size");
2209 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
2210 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
2211 Asm->EmitLabelDifference(end, begin, 2);
2212 Asm->OutStreamer.EmitLabel(begin);
2214 APByteStreamer Streamer(*Asm);
2215 emitDebugLocEntry(Streamer, Entry);
2217 Asm->OutStreamer.EmitLabel(end);
2220 // Emit locations into the debug loc section.
2221 void DwarfDebug::emitDebugLoc() {
2222 // Start the dwarf loc section.
2223 Asm->OutStreamer.SwitchSection(
2224 Asm->getObjFileLowering().getDwarfLocSection());
2225 unsigned char Size = Asm->getDataLayout().getPointerSize();
2226 for (const auto &DebugLoc : DotDebugLocEntries) {
2227 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2228 const DwarfCompileUnit *CU = DebugLoc.CU;
2229 assert(!CU->getRanges().empty());
2230 for (const auto &Entry : DebugLoc.List) {
2231 // Set up the range. This range is relative to the entry point of the
2232 // compile unit. This is a hard coded 0 for low_pc when we're emitting
2233 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
2234 if (CU->getRanges().size() == 1) {
2235 // Grab the begin symbol from the first range as our base.
2236 const MCSymbol *Base = CU->getRanges()[0].getStart();
2237 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
2238 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
2240 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
2241 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
2244 emitDebugLocEntryLocation(Entry);
2246 Asm->OutStreamer.EmitIntValue(0, Size);
2247 Asm->OutStreamer.EmitIntValue(0, Size);
2251 void DwarfDebug::emitDebugLocDWO() {
2252 Asm->OutStreamer.SwitchSection(
2253 Asm->getObjFileLowering().getDwarfLocDWOSection());
2254 for (const auto &DebugLoc : DotDebugLocEntries) {
2255 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2256 for (const auto &Entry : DebugLoc.List) {
2257 // Just always use start_length for now - at least that's one address
2258 // rather than two. We could get fancier and try to, say, reuse an
2259 // address we know we've emitted elsewhere (the start of the function?
2260 // The start of the CU or CU subrange that encloses this range?)
2261 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2262 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2263 Asm->EmitULEB128(idx);
2264 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2266 emitDebugLocEntryLocation(Entry);
2268 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2273 const MCSymbol *Start, *End;
2276 // Emit a debug aranges section, containing a CU lookup for any
2277 // address we can tie back to a CU.
2278 void DwarfDebug::emitDebugARanges() {
2279 // Start the dwarf aranges section.
2280 Asm->OutStreamer.SwitchSection(
2281 Asm->getObjFileLowering().getDwarfARangesSection());
2283 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2287 // Build a list of sections used.
2288 std::vector<const MCSection *> Sections;
2289 for (const auto &it : SectionMap) {
2290 const MCSection *Section = it.first;
2291 Sections.push_back(Section);
2294 // Sort the sections into order.
2295 // This is only done to ensure consistent output order across different runs.
2296 std::sort(Sections.begin(), Sections.end(), SectionSort);
2298 // Build a set of address spans, sorted by CU.
2299 for (const MCSection *Section : Sections) {
2300 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2301 if (List.size() < 2)
2304 // Sort the symbols by offset within the section.
2305 std::sort(List.begin(), List.end(),
2306 [&](const SymbolCU &A, const SymbolCU &B) {
2307 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2308 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2310 // Symbols with no order assigned should be placed at the end.
2311 // (e.g. section end labels)
2319 // If we have no section (e.g. common), just write out
2320 // individual spans for each symbol.
2322 for (const SymbolCU &Cur : List) {
2324 Span.Start = Cur.Sym;
2327 Spans[Cur.CU].push_back(Span);
2330 // Build spans between each label.
2331 const MCSymbol *StartSym = List[0].Sym;
2332 for (size_t n = 1, e = List.size(); n < e; n++) {
2333 const SymbolCU &Prev = List[n - 1];
2334 const SymbolCU &Cur = List[n];
2336 // Try and build the longest span we can within the same CU.
2337 if (Cur.CU != Prev.CU) {
2339 Span.Start = StartSym;
2341 Spans[Prev.CU].push_back(Span);
2348 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2350 // Build a list of CUs used.
2351 std::vector<DwarfCompileUnit *> CUs;
2352 for (const auto &it : Spans) {
2353 DwarfCompileUnit *CU = it.first;
2357 // Sort the CU list (again, to ensure consistent output order).
2358 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2359 return A->getUniqueID() < B->getUniqueID();
2362 // Emit an arange table for each CU we used.
2363 for (DwarfCompileUnit *CU : CUs) {
2364 std::vector<ArangeSpan> &List = Spans[CU];
2366 // Emit size of content not including length itself.
2367 unsigned ContentSize =
2368 sizeof(int16_t) + // DWARF ARange version number
2369 sizeof(int32_t) + // Offset of CU in the .debug_info section
2370 sizeof(int8_t) + // Pointer Size (in bytes)
2371 sizeof(int8_t); // Segment Size (in bytes)
2373 unsigned TupleSize = PtrSize * 2;
2375 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2377 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2379 ContentSize += Padding;
2380 ContentSize += (List.size() + 1) * TupleSize;
2382 // For each compile unit, write the list of spans it covers.
2383 Asm->OutStreamer.AddComment("Length of ARange Set");
2384 Asm->EmitInt32(ContentSize);
2385 Asm->OutStreamer.AddComment("DWARF Arange version number");
2386 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2387 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2388 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2389 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2390 Asm->EmitInt8(PtrSize);
2391 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2394 Asm->OutStreamer.EmitFill(Padding, 0xff);
2396 for (const ArangeSpan &Span : List) {
2397 Asm->EmitLabelReference(Span.Start, PtrSize);
2399 // Calculate the size as being from the span start to it's end.
2401 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2403 // For symbols without an end marker (e.g. common), we
2404 // write a single arange entry containing just that one symbol.
2405 uint64_t Size = SymSize[Span.Start];
2409 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2413 Asm->OutStreamer.AddComment("ARange terminator");
2414 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2415 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2419 // Emit visible names into a debug ranges section.
2420 void DwarfDebug::emitDebugRanges() {
2421 // Start the dwarf ranges section.
2422 Asm->OutStreamer.SwitchSection(
2423 Asm->getObjFileLowering().getDwarfRangesSection());
2425 // Size for our labels.
2426 unsigned char Size = Asm->getDataLayout().getPointerSize();
2428 // Grab the specific ranges for the compile units in the module.
2429 for (const auto &I : CUMap) {
2430 DwarfCompileUnit *TheCU = I.second;
2432 // Iterate over the misc ranges for the compile units in the module.
2433 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2434 // Emit our symbol so we can find the beginning of the range.
2435 Asm->OutStreamer.EmitLabel(List.getSym());
2437 for (const RangeSpan &Range : List.getRanges()) {
2438 const MCSymbol *Begin = Range.getStart();
2439 const MCSymbol *End = Range.getEnd();
2440 assert(Begin && "Range without a begin symbol?");
2441 assert(End && "Range without an end symbol?");
2442 if (TheCU->getRanges().size() == 1) {
2443 // Grab the begin symbol from the first range as our base.
2444 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2445 Asm->EmitLabelDifference(Begin, Base, Size);
2446 Asm->EmitLabelDifference(End, Base, Size);
2448 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2449 Asm->OutStreamer.EmitSymbolValue(End, Size);
2453 // And terminate the list with two 0 values.
2454 Asm->OutStreamer.EmitIntValue(0, Size);
2455 Asm->OutStreamer.EmitIntValue(0, Size);
2458 // Now emit a range for the CU itself.
2459 if (TheCU->getRanges().size() > 1) {
2460 Asm->OutStreamer.EmitLabel(
2461 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2462 for (const RangeSpan &Range : TheCU->getRanges()) {
2463 const MCSymbol *Begin = Range.getStart();
2464 const MCSymbol *End = Range.getEnd();
2465 assert(Begin && "Range without a begin symbol?");
2466 assert(End && "Range without an end symbol?");
2467 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2468 Asm->OutStreamer.EmitSymbolValue(End, Size);
2470 // And terminate the list with two 0 values.
2471 Asm->OutStreamer.EmitIntValue(0, Size);
2472 Asm->OutStreamer.EmitIntValue(0, Size);
2477 // DWARF5 Experimental Separate Dwarf emitters.
2479 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2480 std::unique_ptr<DwarfUnit> NewU) {
2481 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2482 U.getCUNode().getSplitDebugFilename());
2484 if (!CompilationDir.empty())
2485 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2487 addGnuPubAttributes(*NewU, Die);
2489 SkeletonHolder.addUnit(std::move(NewU));
2492 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2493 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2494 // DW_AT_addr_base, DW_AT_ranges_base.
2495 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2497 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2498 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2499 DwarfCompileUnit &NewCU = *OwnedUnit;
2500 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2501 DwarfInfoSectionSym);
2503 NewCU.initStmtList(DwarfLineSectionSym);
2505 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2510 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2511 // compile units that would normally be in debug_info.
2512 void DwarfDebug::emitDebugInfoDWO() {
2513 assert(useSplitDwarf() && "No split dwarf debug info?");
2514 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2515 // emit relocations into the dwo file.
2516 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2519 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2520 // abbreviations for the .debug_info.dwo section.
2521 void DwarfDebug::emitDebugAbbrevDWO() {
2522 assert(useSplitDwarf() && "No split dwarf?");
2523 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2526 void DwarfDebug::emitDebugLineDWO() {
2527 assert(useSplitDwarf() && "No split dwarf?");
2528 Asm->OutStreamer.SwitchSection(
2529 Asm->getObjFileLowering().getDwarfLineDWOSection());
2530 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2533 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2534 // string section and is identical in format to traditional .debug_str
2536 void DwarfDebug::emitDebugStrDWO() {
2537 assert(useSplitDwarf() && "No split dwarf?");
2538 const MCSection *OffSec =
2539 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2540 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2544 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2545 if (!useSplitDwarf())
2548 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2549 return &SplitTypeUnitFileTable;
2552 static uint64_t makeTypeSignature(StringRef Identifier) {
2554 Hash.update(Identifier);
2555 // ... take the least significant 8 bytes and return those. Our MD5
2556 // implementation always returns its results in little endian, swap bytes
2558 MD5::MD5Result Result;
2560 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2563 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2564 StringRef Identifier, DIE &RefDie,
2565 DICompositeType CTy) {
2566 // Fast path if we're building some type units and one has already used the
2567 // address pool we know we're going to throw away all this work anyway, so
2568 // don't bother building dependent types.
2569 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2572 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2574 CU.addDIETypeSignature(RefDie, *TU);
2578 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2579 AddrPool.resetUsedFlag();
2581 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2582 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2583 this, &InfoHolder, getDwoLineTable(CU));
2584 DwarfTypeUnit &NewTU = *OwnedUnit;
2585 DIE &UnitDie = NewTU.getUnitDie();
2587 TypeUnitsUnderConstruction.push_back(
2588 std::make_pair(std::move(OwnedUnit), CTy));
2590 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2593 uint64_t Signature = makeTypeSignature(Identifier);
2594 NewTU.setTypeSignature(Signature);
2596 if (useSplitDwarf())
2597 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2598 DwarfTypesDWOSectionSym);
2600 CU.applyStmtList(UnitDie);
2602 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2605 NewTU.setType(NewTU.createTypeDIE(CTy));
2608 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2609 TypeUnitsUnderConstruction.clear();
2611 // Types referencing entries in the address table cannot be placed in type
2613 if (AddrPool.hasBeenUsed()) {
2615 // Remove all the types built while building this type.
2616 // This is pessimistic as some of these types might not be dependent on
2617 // the type that used an address.
2618 for (const auto &TU : TypeUnitsToAdd)
2619 DwarfTypeUnits.erase(TU.second);
2621 // Construct this type in the CU directly.
2622 // This is inefficient because all the dependent types will be rebuilt
2623 // from scratch, including building them in type units, discovering that
2624 // they depend on addresses, throwing them out and rebuilding them.
2625 CU.constructTypeDIE(RefDie, CTy);
2629 // If the type wasn't dependent on fission addresses, finish adding the type
2630 // and all its dependent types.
2631 for (auto &TU : TypeUnitsToAdd)
2632 InfoHolder.addUnit(std::move(TU.first));
2634 CU.addDIETypeSignature(RefDie, NewTU);
2637 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2638 const MCSymbol *Begin, const MCSymbol *End) {
2639 assert(Begin && "Begin label should not be null!");
2640 assert(End && "End label should not be null!");
2641 assert(Begin->isDefined() && "Invalid starting label");
2642 assert(End->isDefined() && "Invalid end label");
2644 Unit.addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
2645 if (DwarfVersion < 4)
2646 Unit.addLabelAddress(D, dwarf::DW_AT_high_pc, End);
2648 Unit.addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
2651 // Accelerator table mutators - add each name along with its companion
2652 // DIE to the proper table while ensuring that the name that we're going
2653 // to reference is in the string table. We do this since the names we
2654 // add may not only be identical to the names in the DIE.
2655 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2656 if (!useDwarfAccelTables())
2658 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2662 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2663 if (!useDwarfAccelTables())
2665 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2669 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2670 if (!useDwarfAccelTables())
2672 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2676 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2677 if (!useDwarfAccelTables())
2679 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),