1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfDebug.h"
16 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.h"
20 #include "DwarfUnit.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 //===----------------------------------------------------------------------===//
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
151 uint16_t tag = Ty.getTag();
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
173 InfoHolder(A, *this, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
204 HasSplitDwarf = SplitDwarf == Enable;
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
209 HasDwarfPubSections = DwarfPubSections == Enable;
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
224 DwarfDebug::~DwarfDebug() { }
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
247 return Name.find(") ") != StringRef::npos;
250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
267 // Helper for sorting sections into a stable output order.
268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
281 addAccelName(SP.getName(), Die);
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
288 // If this is an Objective-C selector name add it to the ObjC accelerator
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
334 assert(Scope && Scope->getScopeNode());
335 assert(Scope->isAbstractScope());
336 assert(!Scope->getInlinedAt());
338 const MDNode *SP = Scope->getScopeNode();
340 DIE *&AbsDef = AbstractSPDies[SP];
344 ProcessedSPNodes.insert(SP);
346 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
347 // was inlined from another compile unit.
348 AbsDef = &SPMap[SP]->constructAbstractSubprogramScopeDIE(Scope);
351 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
352 if (!GenerateGnuPubSections)
355 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
358 // Create new DwarfCompileUnit for the given metadata node with tag
359 // DW_TAG_compile_unit.
360 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
361 StringRef FN = DIUnit.getFilename();
362 CompilationDir = DIUnit.getDirectory();
364 auto OwnedUnit = make_unique<DwarfCompileUnit>(
365 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
366 DwarfCompileUnit &NewCU = *OwnedUnit;
367 DIE &Die = NewCU.getUnitDie();
368 InfoHolder.addUnit(std::move(OwnedUnit));
370 // LTO with assembly output shares a single line table amongst multiple CUs.
371 // To avoid the compilation directory being ambiguous, let the line table
372 // explicitly describe the directory of all files, never relying on the
373 // compilation directory.
374 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
375 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
376 NewCU.getUniqueID(), CompilationDir);
378 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
379 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
380 DIUnit.getLanguage());
381 NewCU.addString(Die, dwarf::DW_AT_name, FN);
383 if (!useSplitDwarf()) {
384 NewCU.initStmtList(DwarfLineSectionSym);
386 // If we're using split dwarf the compilation dir is going to be in the
387 // skeleton CU and so we don't need to duplicate it here.
388 if (!CompilationDir.empty())
389 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
391 addGnuPubAttributes(NewCU, Die);
394 if (DIUnit.isOptimized())
395 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
397 StringRef Flags = DIUnit.getFlags();
399 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
401 if (unsigned RVer = DIUnit.getRunTimeVersion())
402 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
403 dwarf::DW_FORM_data1, RVer);
405 if (useSplitDwarf()) {
406 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
407 DwarfInfoDWOSectionSym);
408 NewCU.setSkeleton(constructSkeletonCU(NewCU));
410 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
411 DwarfInfoSectionSym);
413 CUMap.insert(std::make_pair(DIUnit, &NewCU));
414 CUDieMap.insert(std::make_pair(&Die, &NewCU));
418 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
420 DIImportedEntity Module(N);
421 assert(Module.Verify());
422 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
423 D->addChild(TheCU.constructImportedEntityDIE(Module));
426 // Emit all Dwarf sections that should come prior to the content. Create
427 // global DIEs and emit initial debug info sections. This is invoked by
428 // the target AsmPrinter.
429 void DwarfDebug::beginModule() {
430 if (DisableDebugInfoPrinting)
433 const Module *M = MMI->getModule();
435 FunctionDIs = makeSubprogramMap(*M);
437 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
440 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
442 // Emit initial sections so we can reference labels later.
445 SingleCU = CU_Nodes->getNumOperands() == 1;
447 for (MDNode *N : CU_Nodes->operands()) {
448 DICompileUnit CUNode(N);
449 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
450 DIArray ImportedEntities = CUNode.getImportedEntities();
451 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
452 ScopesWithImportedEntities.push_back(std::make_pair(
453 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
454 ImportedEntities.getElement(i)));
455 std::sort(ScopesWithImportedEntities.begin(),
456 ScopesWithImportedEntities.end(), less_first());
457 DIArray GVs = CUNode.getGlobalVariables();
458 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
459 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
460 DIArray SPs = CUNode.getSubprograms();
461 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
462 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
463 DIArray EnumTypes = CUNode.getEnumTypes();
464 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
465 DIType Ty(EnumTypes.getElement(i));
466 // The enum types array by design contains pointers to
467 // MDNodes rather than DIRefs. Unique them here.
468 DIType UniqueTy(resolve(Ty.getRef()));
469 CU.getOrCreateTypeDIE(UniqueTy);
471 DIArray RetainedTypes = CUNode.getRetainedTypes();
472 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
473 DIType Ty(RetainedTypes.getElement(i));
474 // The retained types array by design contains pointers to
475 // MDNodes rather than DIRefs. Unique them here.
476 DIType UniqueTy(resolve(Ty.getRef()));
477 CU.getOrCreateTypeDIE(UniqueTy);
479 // Emit imported_modules last so that the relevant context is already
481 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
482 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
485 // Tell MMI that we have debug info.
486 MMI->setDebugInfoAvailability(true);
488 // Prime section data.
489 SectionMap[Asm->getObjFileLowering().getTextSection()];
492 void DwarfDebug::finishVariableDefinitions() {
493 for (const auto &Var : ConcreteVariables) {
494 DIE *VariableDie = Var->getDIE();
496 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
497 // in the ConcreteVariables list, rather than looking it up again here.
498 // DIE::getUnit isn't simple - it walks parent pointers, etc.
499 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
501 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
502 if (AbsVar && AbsVar->getDIE()) {
503 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
506 Unit->applyVariableAttributes(*Var, *VariableDie);
510 void DwarfDebug::finishSubprogramDefinitions() {
511 for (const auto &P : SPMap)
512 P.second->finishSubprogramDefinition(DISubprogram(P.first));
516 // Collect info for variables that were optimized out.
517 void DwarfDebug::collectDeadVariables() {
518 const Module *M = MMI->getModule();
520 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
521 for (MDNode *N : CU_Nodes->operands()) {
522 DICompileUnit TheCU(N);
523 // Construct subprogram DIE and add variables DIEs.
524 DwarfCompileUnit *SPCU =
525 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
526 assert(SPCU && "Unable to find Compile Unit!");
527 DIArray Subprograms = TheCU.getSubprograms();
528 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
529 DISubprogram SP(Subprograms.getElement(i));
530 if (ProcessedSPNodes.count(SP) != 0)
532 assert(SP.isSubprogram() &&
533 "CU's subprogram list contains a non-subprogram");
534 assert(SP.isDefinition() &&
535 "CU's subprogram list contains a subprogram declaration");
536 DIArray Variables = SP.getVariables();
537 if (Variables.getNumElements() == 0)
540 DIE *SPDIE = AbstractSPDies.lookup(SP);
542 SPDIE = SPCU->getDIE(SP);
544 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
545 DIVariable DV(Variables.getElement(vi));
546 assert(DV.isVariable());
547 DbgVariable NewVar(DV, DIExpression(nullptr), this);
548 auto VariableDie = SPCU->constructVariableDIE(NewVar);
549 SPCU->applyVariableAttributes(NewVar, *VariableDie);
550 SPDIE->addChild(std::move(VariableDie));
557 void DwarfDebug::finalizeModuleInfo() {
558 finishSubprogramDefinitions();
560 finishVariableDefinitions();
562 // Collect info for variables that were optimized out.
563 collectDeadVariables();
565 // Handle anything that needs to be done on a per-unit basis after
566 // all other generation.
567 for (const auto &TheU : getUnits()) {
568 // Emit DW_AT_containing_type attribute to connect types with their
569 // vtable holding type.
570 TheU->constructContainingTypeDIEs();
572 // Add CU specific attributes if we need to add any.
573 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
574 // If we're splitting the dwarf out now that we've got the entire
575 // CU then add the dwo id to it.
576 DwarfCompileUnit *SkCU =
577 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
578 if (useSplitDwarf()) {
579 // Emit a unique identifier for this CU.
580 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
581 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
582 dwarf::DW_FORM_data8, ID);
583 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
584 dwarf::DW_FORM_data8, ID);
586 // We don't keep track of which addresses are used in which CU so this
587 // is a bit pessimistic under LTO.
588 if (!AddrPool.isEmpty())
589 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
590 DwarfAddrSectionSym, DwarfAddrSectionSym);
591 if (!TheU->getRangeLists().empty())
592 SkCU->addSectionLabel(
593 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
594 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
597 // If we have code split among multiple sections or non-contiguous
598 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
599 // remain in the .o file, otherwise add a DW_AT_low_pc.
600 // FIXME: We should use ranges allow reordering of code ala
601 // .subsections_via_symbols in mach-o. This would mean turning on
602 // ranges for all subprogram DIEs for mach-o.
603 DwarfCompileUnit &U =
604 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
605 unsigned NumRanges = TheU->getRanges().size();
608 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
609 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
610 DwarfDebugRangeSectionSym);
612 // A DW_AT_low_pc attribute may also be specified in combination with
613 // DW_AT_ranges to specify the default base address for use in
614 // location lists (see Section 2.6.2) and range lists (see Section
616 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
619 RangeSpan &Range = TheU->getRanges().back();
620 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
626 // Compute DIE offsets and sizes.
627 InfoHolder.computeSizeAndOffsets();
629 SkeletonHolder.computeSizeAndOffsets();
632 void DwarfDebug::endSections() {
633 // Filter labels by section.
634 for (const SymbolCU &SCU : ArangeLabels) {
635 if (SCU.Sym->isInSection()) {
636 // Make a note of this symbol and it's section.
637 const MCSection *Section = &SCU.Sym->getSection();
638 if (!Section->getKind().isMetadata())
639 SectionMap[Section].push_back(SCU);
641 // Some symbols (e.g. common/bss on mach-o) can have no section but still
642 // appear in the output. This sucks as we rely on sections to build
643 // arange spans. We can do it without, but it's icky.
644 SectionMap[nullptr].push_back(SCU);
648 // Build a list of sections used.
649 std::vector<const MCSection *> Sections;
650 for (const auto &it : SectionMap) {
651 const MCSection *Section = it.first;
652 Sections.push_back(Section);
655 // Sort the sections into order.
656 // This is only done to ensure consistent output order across different runs.
657 std::sort(Sections.begin(), Sections.end(), SectionSort);
659 // Add terminating symbols for each section.
660 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
661 const MCSection *Section = Sections[ID];
662 MCSymbol *Sym = nullptr;
665 // We can't call MCSection::getLabelEndName, as it's only safe to do so
666 // if we know the section name up-front. For user-created sections, the
667 // resulting label may not be valid to use as a label. (section names can
668 // use a greater set of characters on some systems)
669 Sym = Asm->GetTempSymbol("debug_end", ID);
670 Asm->OutStreamer.SwitchSection(Section);
671 Asm->OutStreamer.EmitLabel(Sym);
674 // Insert a final terminator.
675 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
679 // Emit all Dwarf sections that should come after the content.
680 void DwarfDebug::endModule() {
681 assert(CurFn == nullptr);
682 assert(CurMI == nullptr);
684 // If we aren't actually generating debug info (check beginModule -
685 // conditionalized on !DisableDebugInfoPrinting and the presence of the
686 // llvm.dbg.cu metadata node)
687 if (!DwarfInfoSectionSym)
690 // End any existing sections.
691 // TODO: Does this need to happen?
694 // Finalize the debug info for the module.
695 finalizeModuleInfo();
699 // Emit all the DIEs into a debug info section.
702 // Corresponding abbreviations into a abbrev section.
705 // Emit info into a debug aranges section.
706 if (GenerateARangeSection)
709 // Emit info into a debug ranges section.
712 if (useSplitDwarf()) {
715 emitDebugAbbrevDWO();
718 // Emit DWO addresses.
719 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
721 // Emit info into a debug loc section.
724 // Emit info into the dwarf accelerator table sections.
725 if (useDwarfAccelTables()) {
728 emitAccelNamespaces();
732 // Emit the pubnames and pubtypes sections if requested.
733 if (HasDwarfPubSections) {
734 emitDebugPubNames(GenerateGnuPubSections);
735 emitDebugPubTypes(GenerateGnuPubSections);
740 AbstractVariables.clear();
743 // Find abstract variable, if any, associated with Var.
744 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
745 DIVariable &Cleansed) {
746 LLVMContext &Ctx = DV->getContext();
747 // More then one inlined variable corresponds to one abstract variable.
748 // FIXME: This duplication of variables when inlining should probably be
749 // removed. It's done to allow each DIVariable to describe its location
750 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
751 // make it accurate then remove this duplication/cleansing stuff.
752 Cleansed = cleanseInlinedVariable(DV, Ctx);
753 auto I = AbstractVariables.find(Cleansed);
754 if (I != AbstractVariables.end())
755 return I->second.get();
759 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
761 return getExistingAbstractVariable(DV, Cleansed);
764 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
765 LexicalScope *Scope) {
766 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
767 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
768 AbstractVariables[Var] = std::move(AbsDbgVariable);
771 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
772 const MDNode *ScopeNode) {
773 DIVariable Cleansed = DV;
774 if (getExistingAbstractVariable(DV, Cleansed))
777 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
781 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
782 const MDNode *ScopeNode) {
783 DIVariable Cleansed = DV;
784 if (getExistingAbstractVariable(DV, Cleansed))
787 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
788 createAbstractVariable(Cleansed, Scope);
791 // Collect variable information from side table maintained by MMI.
792 void DwarfDebug::collectVariableInfoFromMMITable(
793 SmallPtrSetImpl<const MDNode *> &Processed) {
794 for (const auto &VI : MMI->getVariableDbgInfo()) {
797 Processed.insert(VI.Var);
798 DIVariable DV(VI.Var);
799 DIExpression Expr(VI.Expr);
800 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
802 // If variable scope is not found then skip this variable.
806 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
807 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
808 DbgVariable *RegVar = ConcreteVariables.back().get();
809 RegVar->setFrameIndex(VI.Slot);
810 InfoHolder.addScopeVariable(Scope, RegVar);
814 // Get .debug_loc entry for the instruction range starting at MI.
815 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
816 const MDNode *Expr = MI->getDebugExpression();
817 const MDNode *Var = MI->getDebugVariable();
819 assert(MI->getNumOperands() == 4);
820 if (MI->getOperand(0).isReg()) {
821 MachineLocation MLoc;
822 // If the second operand is an immediate, this is a
823 // register-indirect address.
824 if (!MI->getOperand(1).isImm())
825 MLoc.set(MI->getOperand(0).getReg());
827 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
828 return DebugLocEntry::Value(Var, Expr, MLoc);
830 if (MI->getOperand(0).isImm())
831 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
832 if (MI->getOperand(0).isFPImm())
833 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
834 if (MI->getOperand(0).isCImm())
835 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
837 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
840 /// Determine whether two variable pieces overlap.
841 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
842 if (!P1.isVariablePiece() || !P2.isVariablePiece())
844 unsigned l1 = P1.getPieceOffset();
845 unsigned l2 = P2.getPieceOffset();
846 unsigned r1 = l1 + P1.getPieceSize();
847 unsigned r2 = l2 + P2.getPieceSize();
848 // True where [l1,r1[ and [r1,r2[ overlap.
849 return (l1 < r2) && (l2 < r1);
852 /// Build the location list for all DBG_VALUEs in the function that
853 /// describe the same variable. If the ranges of several independent
854 /// pieces of the same variable overlap partially, split them up and
855 /// combine the ranges. The resulting DebugLocEntries are will have
856 /// strict monotonically increasing begin addresses and will never
861 // Ranges History [var, loc, piece ofs size]
862 // 0 | [x, (reg0, piece 0, 32)]
863 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
865 // 3 | [clobber reg0]
866 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
870 // [0-1] [x, (reg0, piece 0, 32)]
871 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
872 // [3-4] [x, (reg1, piece 32, 32)]
873 // [4- ] [x, (mem, piece 0, 64)]
875 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
876 const DbgValueHistoryMap::InstrRanges &Ranges) {
877 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
879 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
880 const MachineInstr *Begin = I->first;
881 const MachineInstr *End = I->second;
882 assert(Begin->isDebugValue() && "Invalid History entry");
884 // Check if a variable is inaccessible in this range.
885 if (Begin->getNumOperands() > 1 &&
886 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
891 // If this piece overlaps with any open ranges, truncate them.
892 DIExpression DIExpr = Begin->getDebugExpression();
893 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
894 [&](DebugLocEntry::Value R) {
895 return piecesOverlap(DIExpr, R.getExpression());
897 OpenRanges.erase(Last, OpenRanges.end());
899 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
900 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
902 const MCSymbol *EndLabel;
904 EndLabel = getLabelAfterInsn(End);
905 else if (std::next(I) == Ranges.end())
906 EndLabel = FunctionEndSym;
908 EndLabel = getLabelBeforeInsn(std::next(I)->first);
909 assert(EndLabel && "Forgot label after instruction ending a range!");
911 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
913 auto Value = getDebugLocValue(Begin);
914 DebugLocEntry Loc(StartLabel, EndLabel, Value);
915 bool couldMerge = false;
917 // If this is a piece, it may belong to the current DebugLocEntry.
918 if (DIExpr.isVariablePiece()) {
919 // Add this value to the list of open ranges.
920 OpenRanges.push_back(Value);
922 // Attempt to add the piece to the last entry.
923 if (!DebugLoc.empty())
924 if (DebugLoc.back().MergeValues(Loc))
929 // Need to add a new DebugLocEntry. Add all values from still
930 // valid non-overlapping pieces.
931 if (OpenRanges.size())
932 Loc.addValues(OpenRanges);
934 DebugLoc.push_back(std::move(Loc));
937 // Attempt to coalesce the ranges of two otherwise identical
939 auto CurEntry = DebugLoc.rbegin();
940 auto PrevEntry = std::next(CurEntry);
941 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
945 dbgs() << CurEntry->getValues().size() << " Values:\n";
946 for (auto Value : CurEntry->getValues()) {
947 Value.getVariable()->dump();
948 Value.getExpression()->dump();
956 // Find variables for each lexical scope.
958 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
959 SmallPtrSetImpl<const MDNode *> &Processed) {
960 // Grab the variable info that was squirreled away in the MMI side-table.
961 collectVariableInfoFromMMITable(Processed);
963 for (const auto &I : DbgValues) {
964 DIVariable DV(I.first);
965 if (Processed.count(DV))
968 // Instruction ranges, specifying where DV is accessible.
969 const auto &Ranges = I.second;
973 LexicalScope *Scope = nullptr;
974 if (MDNode *IA = DV.getInlinedAt()) {
975 DebugLoc DL = DebugLoc::getFromDILocation(IA);
976 Scope = LScopes.findInlinedScope(DebugLoc::get(
977 DL.getLine(), DL.getCol(), DV.getContext(), IA));
979 Scope = LScopes.findLexicalScope(DV.getContext());
980 // If variable scope is not found then skip this variable.
984 Processed.insert(DV);
985 const MachineInstr *MInsn = Ranges.front().first;
986 assert(MInsn->isDebugValue() && "History must begin with debug value");
987 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
988 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
989 DbgVariable *RegVar = ConcreteVariables.back().get();
990 InfoHolder.addScopeVariable(Scope, RegVar);
992 // Check if the first DBG_VALUE is valid for the rest of the function.
993 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
996 // Handle multiple DBG_VALUE instructions describing one variable.
997 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
999 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1000 DebugLocList &LocList = DotDebugLocEntries.back();
1001 LocList.CU = &TheCU;
1003 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1005 // Build the location list for this variable.
1006 buildLocationList(LocList.List, Ranges);
1009 // Collect info for variables that were optimized out.
1010 DIArray Variables = SP.getVariables();
1011 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1012 DIVariable DV(Variables.getElement(i));
1013 assert(DV.isVariable());
1014 if (!Processed.insert(DV))
1016 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1017 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1018 DIExpression NoExpr;
1019 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
1020 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1025 // Return Label preceding the instruction.
1026 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1027 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1028 assert(Label && "Didn't insert label before instruction");
1032 // Return Label immediately following the instruction.
1033 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1034 return LabelsAfterInsn.lookup(MI);
1037 // Process beginning of an instruction.
1038 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1039 assert(CurMI == nullptr);
1041 // Check if source location changes, but ignore DBG_VALUE locations.
1042 if (!MI->isDebugValue()) {
1043 DebugLoc DL = MI->getDebugLoc();
1044 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1047 if (DL == PrologEndLoc) {
1048 Flags |= DWARF2_FLAG_PROLOGUE_END;
1049 PrologEndLoc = DebugLoc();
1051 if (PrologEndLoc.isUnknown())
1052 Flags |= DWARF2_FLAG_IS_STMT;
1054 if (!DL.isUnknown()) {
1055 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1056 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1058 recordSourceLine(0, 0, nullptr, 0);
1062 // Insert labels where requested.
1063 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1064 LabelsBeforeInsn.find(MI);
1067 if (I == LabelsBeforeInsn.end())
1070 // Label already assigned.
1075 PrevLabel = MMI->getContext().CreateTempSymbol();
1076 Asm->OutStreamer.EmitLabel(PrevLabel);
1078 I->second = PrevLabel;
1081 // Process end of an instruction.
1082 void DwarfDebug::endInstruction() {
1083 assert(CurMI != nullptr);
1084 // Don't create a new label after DBG_VALUE instructions.
1085 // They don't generate code.
1086 if (!CurMI->isDebugValue())
1087 PrevLabel = nullptr;
1089 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1090 LabelsAfterInsn.find(CurMI);
1094 if (I == LabelsAfterInsn.end())
1097 // Label already assigned.
1101 // We need a label after this instruction.
1103 PrevLabel = MMI->getContext().CreateTempSymbol();
1104 Asm->OutStreamer.EmitLabel(PrevLabel);
1106 I->second = PrevLabel;
1109 // Each LexicalScope has first instruction and last instruction to mark
1110 // beginning and end of a scope respectively. Create an inverse map that list
1111 // scopes starts (and ends) with an instruction. One instruction may start (or
1112 // end) multiple scopes. Ignore scopes that are not reachable.
1113 void DwarfDebug::identifyScopeMarkers() {
1114 SmallVector<LexicalScope *, 4> WorkList;
1115 WorkList.push_back(LScopes.getCurrentFunctionScope());
1116 while (!WorkList.empty()) {
1117 LexicalScope *S = WorkList.pop_back_val();
1119 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1120 if (!Children.empty())
1121 WorkList.append(Children.begin(), Children.end());
1123 if (S->isAbstractScope())
1126 for (const InsnRange &R : S->getRanges()) {
1127 assert(R.first && "InsnRange does not have first instruction!");
1128 assert(R.second && "InsnRange does not have second instruction!");
1129 requestLabelBeforeInsn(R.first);
1130 requestLabelAfterInsn(R.second);
1135 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1136 // First known non-DBG_VALUE and non-frame setup location marks
1137 // the beginning of the function body.
1138 for (const auto &MBB : *MF)
1139 for (const auto &MI : MBB)
1140 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1141 !MI.getDebugLoc().isUnknown())
1142 return MI.getDebugLoc();
1146 // Gather pre-function debug information. Assumes being called immediately
1147 // after the function entry point has been emitted.
1148 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1151 // If there's no debug info for the function we're not going to do anything.
1152 if (!MMI->hasDebugInfo())
1155 auto DI = FunctionDIs.find(MF->getFunction());
1156 if (DI == FunctionDIs.end())
1159 // Grab the lexical scopes for the function, if we don't have any of those
1160 // then we're not going to be able to do anything.
1161 LScopes.initialize(*MF);
1162 if (LScopes.empty())
1165 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1167 // Make sure that each lexical scope will have a begin/end label.
1168 identifyScopeMarkers();
1170 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1171 // belongs to so that we add to the correct per-cu line table in the
1173 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1174 // FnScope->getScopeNode() and DI->second should represent the same function,
1175 // though they may not be the same MDNode due to inline functions merged in
1176 // LTO where the debug info metadata still differs (either due to distinct
1177 // written differences - two versions of a linkonce_odr function
1178 // written/copied into two separate files, or some sub-optimal metadata that
1179 // isn't structurally identical (see: file path/name info from clang, which
1180 // includes the directory of the cpp file being built, even when the file name
1181 // is absolute (such as an <> lookup header)))
1182 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1183 assert(TheCU && "Unable to find compile unit!");
1184 if (Asm->OutStreamer.hasRawTextSupport())
1185 // Use a single line table if we are generating assembly.
1186 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1188 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1190 // Emit a label for the function so that we have a beginning address.
1191 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1192 // Assumes in correct section after the entry point.
1193 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1195 // Calculate history for local variables.
1196 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1199 // Request labels for the full history.
1200 for (const auto &I : DbgValues) {
1201 const auto &Ranges = I.second;
1205 // The first mention of a function argument gets the FunctionBeginSym
1206 // label, so arguments are visible when breaking at function entry.
1207 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1208 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1209 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1210 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1211 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1212 // Mark all non-overlapping initial pieces.
1213 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1214 DIExpression Piece = I->first->getDebugExpression();
1215 if (std::all_of(Ranges.begin(), I,
1216 [&](DbgValueHistoryMap::InstrRange Pred) {
1217 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1219 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1226 for (const auto &Range : Ranges) {
1227 requestLabelBeforeInsn(Range.first);
1229 requestLabelAfterInsn(Range.second);
1233 PrevInstLoc = DebugLoc();
1234 PrevLabel = FunctionBeginSym;
1236 // Record beginning of function.
1237 PrologEndLoc = findPrologueEndLoc(MF);
1238 if (!PrologEndLoc.isUnknown()) {
1239 DebugLoc FnStartDL =
1240 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1242 FnStartDL.getLine(), FnStartDL.getCol(),
1243 FnStartDL.getScope(MF->getFunction()->getContext()),
1244 // We'd like to list the prologue as "not statements" but GDB behaves
1245 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1246 DWARF2_FLAG_IS_STMT);
1250 // Gather and emit post-function debug information.
1251 void DwarfDebug::endFunction(const MachineFunction *MF) {
1252 assert(CurFn == MF &&
1253 "endFunction should be called with the same function as beginFunction");
1255 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1256 !FunctionDIs.count(MF->getFunction())) {
1257 // If we don't have a lexical scope for this function then there will
1258 // be a hole in the range information. Keep note of this by setting the
1259 // previously used section to nullptr.
1265 // Define end label for subprogram.
1266 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1267 // Assumes in correct section after the entry point.
1268 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1270 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1271 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1273 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1274 DISubprogram SP(FnScope->getScopeNode());
1275 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1277 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1278 collectVariableInfo(TheCU, SP, ProcessedVars);
1280 // Add the range of this function to the list of ranges for the CU.
1281 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1283 // Under -gmlt, skip building the subprogram if there are no inlined
1284 // subroutines inside it.
1285 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1286 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1287 assert(InfoHolder.getScopeVariables().empty());
1288 assert(DbgValues.empty());
1289 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1290 // by a -gmlt CU. Add a test and remove this assertion.
1291 assert(AbstractVariables.empty());
1292 LabelsBeforeInsn.clear();
1293 LabelsAfterInsn.clear();
1294 PrevLabel = nullptr;
1300 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1302 // Construct abstract scopes.
1303 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1304 DISubprogram SP(AScope->getScopeNode());
1305 assert(SP.isSubprogram());
1306 // Collect info for variables that were optimized out.
1307 DIArray Variables = SP.getVariables();
1308 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1309 DIVariable DV(Variables.getElement(i));
1310 assert(DV && DV.isVariable());
1311 if (!ProcessedVars.insert(DV))
1313 ensureAbstractVariableIsCreated(DV, DV.getContext());
1314 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1315 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1317 constructAbstractSubprogramScopeDIE(AScope);
1320 TheCU.constructSubprogramScopeDIE(FnScope);
1323 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1324 // DbgVariables except those that are also in AbstractVariables (since they
1325 // can be used cross-function)
1326 InfoHolder.getScopeVariables().clear();
1328 LabelsBeforeInsn.clear();
1329 LabelsAfterInsn.clear();
1330 PrevLabel = nullptr;
1334 // Register a source line with debug info. Returns the unique label that was
1335 // emitted and which provides correspondence to the source line list.
1336 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1341 unsigned Discriminator = 0;
1342 if (DIScope Scope = DIScope(S)) {
1343 assert(Scope.isScope());
1344 Fn = Scope.getFilename();
1345 Dir = Scope.getDirectory();
1346 if (Scope.isLexicalBlockFile())
1347 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1349 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1350 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1351 .getOrCreateSourceID(Fn, Dir);
1353 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1357 //===----------------------------------------------------------------------===//
1359 //===----------------------------------------------------------------------===//
1361 // Emit initial Dwarf sections with a label at the start of each one.
1362 void DwarfDebug::emitSectionLabels() {
1363 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1365 // Dwarf sections base addresses.
1366 DwarfInfoSectionSym =
1367 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1368 if (useSplitDwarf()) {
1369 DwarfInfoDWOSectionSym =
1370 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1371 DwarfTypesDWOSectionSym =
1372 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1374 DwarfAbbrevSectionSym =
1375 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1376 if (useSplitDwarf())
1377 DwarfAbbrevDWOSectionSym = emitSectionSym(
1378 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1379 if (GenerateARangeSection)
1380 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1382 DwarfLineSectionSym =
1383 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1384 if (GenerateGnuPubSections) {
1385 DwarfGnuPubNamesSectionSym =
1386 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1387 DwarfGnuPubTypesSectionSym =
1388 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1389 } else if (HasDwarfPubSections) {
1390 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1391 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1394 DwarfStrSectionSym =
1395 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1396 if (useSplitDwarf()) {
1397 DwarfStrDWOSectionSym =
1398 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1399 DwarfAddrSectionSym =
1400 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1401 DwarfDebugLocSectionSym =
1402 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1404 DwarfDebugLocSectionSym =
1405 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1406 DwarfDebugRangeSectionSym =
1407 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1410 // Recursively emits a debug information entry.
1411 void DwarfDebug::emitDIE(DIE &Die) {
1412 // Get the abbreviation for this DIE.
1413 const DIEAbbrev &Abbrev = Die.getAbbrev();
1415 // Emit the code (index) for the abbreviation.
1416 if (Asm->isVerbose())
1417 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1418 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1419 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1420 dwarf::TagString(Abbrev.getTag()));
1421 Asm->EmitULEB128(Abbrev.getNumber());
1423 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1424 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1426 // Emit the DIE attribute values.
1427 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1428 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1429 dwarf::Form Form = AbbrevData[i].getForm();
1430 assert(Form && "Too many attributes for DIE (check abbreviation)");
1432 if (Asm->isVerbose()) {
1433 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1434 if (Attr == dwarf::DW_AT_accessibility)
1435 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1436 cast<DIEInteger>(Values[i])->getValue()));
1439 // Emit an attribute using the defined form.
1440 Values[i]->EmitValue(Asm, Form);
1443 // Emit the DIE children if any.
1444 if (Abbrev.hasChildren()) {
1445 for (auto &Child : Die.getChildren())
1448 Asm->OutStreamer.AddComment("End Of Children Mark");
1453 // Emit the debug info section.
1454 void DwarfDebug::emitDebugInfo() {
1455 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1457 Holder.emitUnits(DwarfAbbrevSectionSym);
1460 // Emit the abbreviation section.
1461 void DwarfDebug::emitAbbreviations() {
1462 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1464 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1467 // Emit the last address of the section and the end of the line matrix.
1468 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1469 // Define last address of section.
1470 Asm->OutStreamer.AddComment("Extended Op");
1473 Asm->OutStreamer.AddComment("Op size");
1474 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1475 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1476 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1478 Asm->OutStreamer.AddComment("Section end label");
1480 Asm->OutStreamer.EmitSymbolValue(
1481 Asm->GetTempSymbol("section_end", SectionEnd),
1482 Asm->getDataLayout().getPointerSize());
1484 // Mark end of matrix.
1485 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1491 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1492 StringRef TableName, StringRef SymName) {
1493 Accel.FinalizeTable(Asm, TableName);
1494 Asm->OutStreamer.SwitchSection(Section);
1495 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1496 Asm->OutStreamer.EmitLabel(SectionBegin);
1498 // Emit the full data.
1499 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1502 // Emit visible names into a hashed accelerator table section.
1503 void DwarfDebug::emitAccelNames() {
1504 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1505 "Names", "names_begin");
1508 // Emit objective C classes and categories into a hashed accelerator table
1510 void DwarfDebug::emitAccelObjC() {
1511 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1512 "ObjC", "objc_begin");
1515 // Emit namespace dies into a hashed accelerator table.
1516 void DwarfDebug::emitAccelNamespaces() {
1517 emitAccel(AccelNamespace,
1518 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1519 "namespac", "namespac_begin");
1522 // Emit type dies into a hashed accelerator table.
1523 void DwarfDebug::emitAccelTypes() {
1524 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1525 "types", "types_begin");
1528 // Public name handling.
1529 // The format for the various pubnames:
1531 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1532 // for the DIE that is named.
1534 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1535 // into the CU and the index value is computed according to the type of value
1536 // for the DIE that is named.
1538 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1539 // it's the offset within the debug_info/debug_types dwo section, however, the
1540 // reference in the pubname header doesn't change.
1542 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1543 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1545 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1547 // We could have a specification DIE that has our most of our knowledge,
1548 // look for that now.
1549 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1551 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1552 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1553 Linkage = dwarf::GIEL_EXTERNAL;
1554 } else if (Die->findAttribute(dwarf::DW_AT_external))
1555 Linkage = dwarf::GIEL_EXTERNAL;
1557 switch (Die->getTag()) {
1558 case dwarf::DW_TAG_class_type:
1559 case dwarf::DW_TAG_structure_type:
1560 case dwarf::DW_TAG_union_type:
1561 case dwarf::DW_TAG_enumeration_type:
1562 return dwarf::PubIndexEntryDescriptor(
1563 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1564 ? dwarf::GIEL_STATIC
1565 : dwarf::GIEL_EXTERNAL);
1566 case dwarf::DW_TAG_typedef:
1567 case dwarf::DW_TAG_base_type:
1568 case dwarf::DW_TAG_subrange_type:
1569 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1570 case dwarf::DW_TAG_namespace:
1571 return dwarf::GIEK_TYPE;
1572 case dwarf::DW_TAG_subprogram:
1573 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1574 case dwarf::DW_TAG_constant:
1575 case dwarf::DW_TAG_variable:
1576 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1577 case dwarf::DW_TAG_enumerator:
1578 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1579 dwarf::GIEL_STATIC);
1581 return dwarf::GIEK_NONE;
1585 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1587 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1588 const MCSection *PSec =
1589 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1590 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1592 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1595 void DwarfDebug::emitDebugPubSection(
1596 bool GnuStyle, const MCSection *PSec, StringRef Name,
1597 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1598 for (const auto &NU : CUMap) {
1599 DwarfCompileUnit *TheU = NU.second;
1601 const auto &Globals = (TheU->*Accessor)();
1603 if (Globals.empty())
1606 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1608 unsigned ID = TheU->getUniqueID();
1610 // Start the dwarf pubnames section.
1611 Asm->OutStreamer.SwitchSection(PSec);
1614 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1615 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1616 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1617 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1619 Asm->OutStreamer.EmitLabel(BeginLabel);
1621 Asm->OutStreamer.AddComment("DWARF Version");
1622 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1624 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1625 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1627 Asm->OutStreamer.AddComment("Compilation Unit Length");
1628 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1630 // Emit the pubnames for this compilation unit.
1631 for (const auto &GI : Globals) {
1632 const char *Name = GI.getKeyData();
1633 const DIE *Entity = GI.second;
1635 Asm->OutStreamer.AddComment("DIE offset");
1636 Asm->EmitInt32(Entity->getOffset());
1639 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1640 Asm->OutStreamer.AddComment(
1641 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1642 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1643 Asm->EmitInt8(Desc.toBits());
1646 Asm->OutStreamer.AddComment("External Name");
1647 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1650 Asm->OutStreamer.AddComment("End Mark");
1652 Asm->OutStreamer.EmitLabel(EndLabel);
1656 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1657 const MCSection *PSec =
1658 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1659 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1661 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1664 // Emit visible names into a debug str section.
1665 void DwarfDebug::emitDebugStr() {
1666 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1667 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1670 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1671 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1672 const DITypeIdentifierMap &Map,
1673 ArrayRef<DebugLocEntry::Value> Values) {
1674 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1675 return P.isVariablePiece();
1676 }) && "all values are expected to be pieces");
1677 assert(std::is_sorted(Values.begin(), Values.end()) &&
1678 "pieces are expected to be sorted");
1680 unsigned Offset = 0;
1681 for (auto Piece : Values) {
1682 DIExpression Expr = Piece.getExpression();
1683 unsigned PieceOffset = Expr.getPieceOffset();
1684 unsigned PieceSize = Expr.getPieceSize();
1685 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1686 if (Offset < PieceOffset) {
1687 // The DWARF spec seriously mandates pieces with no locations for gaps.
1688 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1689 Offset += PieceOffset-Offset;
1692 Offset += PieceSize;
1694 const unsigned SizeOfByte = 8;
1696 DIVariable Var = Piece.getVariable();
1697 assert(!Var.isIndirect() && "indirect address for piece");
1698 unsigned VarSize = Var.getSizeInBits(Map);
1699 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1700 && "piece is larger than or outside of variable");
1701 assert(PieceSize*SizeOfByte != VarSize
1702 && "piece covers entire variable");
1704 if (Piece.isLocation() && Piece.getLoc().isReg())
1705 Asm->EmitDwarfRegOpPiece(Streamer,
1707 PieceSize*SizeOfByte);
1709 emitDebugLocValue(Streamer, Piece);
1710 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1716 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1717 const DebugLocEntry &Entry) {
1718 const DebugLocEntry::Value Value = Entry.getValues()[0];
1719 if (Value.isVariablePiece())
1720 // Emit all pieces that belong to the same variable and range.
1721 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1723 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1724 emitDebugLocValue(Streamer, Value);
1727 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1728 const DebugLocEntry::Value &Value) {
1729 DIVariable DV = Value.getVariable();
1731 if (Value.isInt()) {
1732 DIBasicType BTy(resolve(DV.getType()));
1733 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1734 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1735 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1736 Streamer.EmitSLEB128(Value.getInt());
1738 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1739 Streamer.EmitULEB128(Value.getInt());
1741 } else if (Value.isLocation()) {
1742 MachineLocation Loc = Value.getLoc();
1743 DIExpression Expr = Value.getExpression();
1746 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1748 // Complex address entry.
1749 unsigned N = Expr.getNumElements();
1751 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1752 if (Loc.getOffset()) {
1754 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1755 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1756 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1757 Streamer.EmitSLEB128(Expr.getElement(1));
1759 // If first address element is OpPlus then emit
1760 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1761 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1762 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1766 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1769 // Emit remaining complex address elements.
1770 for (; i < N; ++i) {
1771 uint64_t Element = Expr.getElement(i);
1772 if (Element == dwarf::DW_OP_plus) {
1773 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1774 Streamer.EmitULEB128(Expr.getElement(++i));
1775 } else if (Element == dwarf::DW_OP_deref) {
1777 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1778 } else if (Element == dwarf::DW_OP_piece) {
1780 // handled in emitDebugLocEntry.
1782 llvm_unreachable("unknown Opcode found in complex address");
1786 // else ... ignore constant fp. There is not any good way to
1787 // to represent them here in dwarf.
1791 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1792 Asm->OutStreamer.AddComment("Loc expr size");
1793 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1794 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1795 Asm->EmitLabelDifference(end, begin, 2);
1796 Asm->OutStreamer.EmitLabel(begin);
1798 APByteStreamer Streamer(*Asm);
1799 emitDebugLocEntry(Streamer, Entry);
1801 Asm->OutStreamer.EmitLabel(end);
1804 // Emit locations into the debug loc section.
1805 void DwarfDebug::emitDebugLoc() {
1806 // Start the dwarf loc section.
1807 Asm->OutStreamer.SwitchSection(
1808 Asm->getObjFileLowering().getDwarfLocSection());
1809 unsigned char Size = Asm->getDataLayout().getPointerSize();
1810 for (const auto &DebugLoc : DotDebugLocEntries) {
1811 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1812 const DwarfCompileUnit *CU = DebugLoc.CU;
1813 assert(!CU->getRanges().empty());
1814 for (const auto &Entry : DebugLoc.List) {
1815 // Set up the range. This range is relative to the entry point of the
1816 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1817 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1818 if (CU->getRanges().size() == 1) {
1819 // Grab the begin symbol from the first range as our base.
1820 const MCSymbol *Base = CU->getRanges()[0].getStart();
1821 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1822 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1824 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1825 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1828 emitDebugLocEntryLocation(Entry);
1830 Asm->OutStreamer.EmitIntValue(0, Size);
1831 Asm->OutStreamer.EmitIntValue(0, Size);
1835 void DwarfDebug::emitDebugLocDWO() {
1836 Asm->OutStreamer.SwitchSection(
1837 Asm->getObjFileLowering().getDwarfLocDWOSection());
1838 for (const auto &DebugLoc : DotDebugLocEntries) {
1839 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1840 for (const auto &Entry : DebugLoc.List) {
1841 // Just always use start_length for now - at least that's one address
1842 // rather than two. We could get fancier and try to, say, reuse an
1843 // address we know we've emitted elsewhere (the start of the function?
1844 // The start of the CU or CU subrange that encloses this range?)
1845 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1846 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1847 Asm->EmitULEB128(idx);
1848 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1850 emitDebugLocEntryLocation(Entry);
1852 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1857 const MCSymbol *Start, *End;
1860 // Emit a debug aranges section, containing a CU lookup for any
1861 // address we can tie back to a CU.
1862 void DwarfDebug::emitDebugARanges() {
1863 // Start the dwarf aranges section.
1864 Asm->OutStreamer.SwitchSection(
1865 Asm->getObjFileLowering().getDwarfARangesSection());
1867 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1871 // Build a list of sections used.
1872 std::vector<const MCSection *> Sections;
1873 for (const auto &it : SectionMap) {
1874 const MCSection *Section = it.first;
1875 Sections.push_back(Section);
1878 // Sort the sections into order.
1879 // This is only done to ensure consistent output order across different runs.
1880 std::sort(Sections.begin(), Sections.end(), SectionSort);
1882 // Build a set of address spans, sorted by CU.
1883 for (const MCSection *Section : Sections) {
1884 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1885 if (List.size() < 2)
1888 // Sort the symbols by offset within the section.
1889 std::sort(List.begin(), List.end(),
1890 [&](const SymbolCU &A, const SymbolCU &B) {
1891 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1892 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1894 // Symbols with no order assigned should be placed at the end.
1895 // (e.g. section end labels)
1903 // If we have no section (e.g. common), just write out
1904 // individual spans for each symbol.
1906 for (const SymbolCU &Cur : List) {
1908 Span.Start = Cur.Sym;
1911 Spans[Cur.CU].push_back(Span);
1914 // Build spans between each label.
1915 const MCSymbol *StartSym = List[0].Sym;
1916 for (size_t n = 1, e = List.size(); n < e; n++) {
1917 const SymbolCU &Prev = List[n - 1];
1918 const SymbolCU &Cur = List[n];
1920 // Try and build the longest span we can within the same CU.
1921 if (Cur.CU != Prev.CU) {
1923 Span.Start = StartSym;
1925 Spans[Prev.CU].push_back(Span);
1932 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1934 // Build a list of CUs used.
1935 std::vector<DwarfCompileUnit *> CUs;
1936 for (const auto &it : Spans) {
1937 DwarfCompileUnit *CU = it.first;
1941 // Sort the CU list (again, to ensure consistent output order).
1942 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1943 return A->getUniqueID() < B->getUniqueID();
1946 // Emit an arange table for each CU we used.
1947 for (DwarfCompileUnit *CU : CUs) {
1948 std::vector<ArangeSpan> &List = Spans[CU];
1950 // Emit size of content not including length itself.
1951 unsigned ContentSize =
1952 sizeof(int16_t) + // DWARF ARange version number
1953 sizeof(int32_t) + // Offset of CU in the .debug_info section
1954 sizeof(int8_t) + // Pointer Size (in bytes)
1955 sizeof(int8_t); // Segment Size (in bytes)
1957 unsigned TupleSize = PtrSize * 2;
1959 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1961 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1963 ContentSize += Padding;
1964 ContentSize += (List.size() + 1) * TupleSize;
1966 // For each compile unit, write the list of spans it covers.
1967 Asm->OutStreamer.AddComment("Length of ARange Set");
1968 Asm->EmitInt32(ContentSize);
1969 Asm->OutStreamer.AddComment("DWARF Arange version number");
1970 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1971 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1972 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1973 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1974 Asm->EmitInt8(PtrSize);
1975 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1978 Asm->OutStreamer.EmitFill(Padding, 0xff);
1980 for (const ArangeSpan &Span : List) {
1981 Asm->EmitLabelReference(Span.Start, PtrSize);
1983 // Calculate the size as being from the span start to it's end.
1985 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1987 // For symbols without an end marker (e.g. common), we
1988 // write a single arange entry containing just that one symbol.
1989 uint64_t Size = SymSize[Span.Start];
1993 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1997 Asm->OutStreamer.AddComment("ARange terminator");
1998 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1999 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2003 // Emit visible names into a debug ranges section.
2004 void DwarfDebug::emitDebugRanges() {
2005 // Start the dwarf ranges section.
2006 Asm->OutStreamer.SwitchSection(
2007 Asm->getObjFileLowering().getDwarfRangesSection());
2009 // Size for our labels.
2010 unsigned char Size = Asm->getDataLayout().getPointerSize();
2012 // Grab the specific ranges for the compile units in the module.
2013 for (const auto &I : CUMap) {
2014 DwarfCompileUnit *TheCU = I.second;
2016 // Iterate over the misc ranges for the compile units in the module.
2017 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2018 // Emit our symbol so we can find the beginning of the range.
2019 Asm->OutStreamer.EmitLabel(List.getSym());
2021 for (const RangeSpan &Range : List.getRanges()) {
2022 const MCSymbol *Begin = Range.getStart();
2023 const MCSymbol *End = Range.getEnd();
2024 assert(Begin && "Range without a begin symbol?");
2025 assert(End && "Range without an end symbol?");
2026 if (TheCU->getRanges().size() == 1) {
2027 // Grab the begin symbol from the first range as our base.
2028 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2029 Asm->EmitLabelDifference(Begin, Base, Size);
2030 Asm->EmitLabelDifference(End, Base, Size);
2032 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2033 Asm->OutStreamer.EmitSymbolValue(End, Size);
2037 // And terminate the list with two 0 values.
2038 Asm->OutStreamer.EmitIntValue(0, Size);
2039 Asm->OutStreamer.EmitIntValue(0, Size);
2042 // Now emit a range for the CU itself.
2043 if (TheCU->getRanges().size() > 1) {
2044 Asm->OutStreamer.EmitLabel(
2045 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2046 for (const RangeSpan &Range : TheCU->getRanges()) {
2047 const MCSymbol *Begin = Range.getStart();
2048 const MCSymbol *End = Range.getEnd();
2049 assert(Begin && "Range without a begin symbol?");
2050 assert(End && "Range without an end symbol?");
2051 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2052 Asm->OutStreamer.EmitSymbolValue(End, Size);
2054 // And terminate the list with two 0 values.
2055 Asm->OutStreamer.EmitIntValue(0, Size);
2056 Asm->OutStreamer.EmitIntValue(0, Size);
2061 // DWARF5 Experimental Separate Dwarf emitters.
2063 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2064 std::unique_ptr<DwarfUnit> NewU) {
2065 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2066 U.getCUNode().getSplitDebugFilename());
2068 if (!CompilationDir.empty())
2069 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2071 addGnuPubAttributes(*NewU, Die);
2073 SkeletonHolder.addUnit(std::move(NewU));
2076 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2077 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2078 // DW_AT_addr_base, DW_AT_ranges_base.
2079 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2081 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2082 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2083 DwarfCompileUnit &NewCU = *OwnedUnit;
2084 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2085 DwarfInfoSectionSym);
2087 NewCU.initStmtList(DwarfLineSectionSym);
2089 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2094 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2095 // compile units that would normally be in debug_info.
2096 void DwarfDebug::emitDebugInfoDWO() {
2097 assert(useSplitDwarf() && "No split dwarf debug info?");
2098 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2099 // emit relocations into the dwo file.
2100 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2103 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2104 // abbreviations for the .debug_info.dwo section.
2105 void DwarfDebug::emitDebugAbbrevDWO() {
2106 assert(useSplitDwarf() && "No split dwarf?");
2107 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2110 void DwarfDebug::emitDebugLineDWO() {
2111 assert(useSplitDwarf() && "No split dwarf?");
2112 Asm->OutStreamer.SwitchSection(
2113 Asm->getObjFileLowering().getDwarfLineDWOSection());
2114 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2117 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2118 // string section and is identical in format to traditional .debug_str
2120 void DwarfDebug::emitDebugStrDWO() {
2121 assert(useSplitDwarf() && "No split dwarf?");
2122 const MCSection *OffSec =
2123 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2124 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2128 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2129 if (!useSplitDwarf())
2132 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2133 return &SplitTypeUnitFileTable;
2136 static uint64_t makeTypeSignature(StringRef Identifier) {
2138 Hash.update(Identifier);
2139 // ... take the least significant 8 bytes and return those. Our MD5
2140 // implementation always returns its results in little endian, swap bytes
2142 MD5::MD5Result Result;
2144 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2147 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2148 StringRef Identifier, DIE &RefDie,
2149 DICompositeType CTy) {
2150 // Fast path if we're building some type units and one has already used the
2151 // address pool we know we're going to throw away all this work anyway, so
2152 // don't bother building dependent types.
2153 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2156 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2158 CU.addDIETypeSignature(RefDie, *TU);
2162 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2163 AddrPool.resetUsedFlag();
2165 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2166 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2167 this, &InfoHolder, getDwoLineTable(CU));
2168 DwarfTypeUnit &NewTU = *OwnedUnit;
2169 DIE &UnitDie = NewTU.getUnitDie();
2171 TypeUnitsUnderConstruction.push_back(
2172 std::make_pair(std::move(OwnedUnit), CTy));
2174 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2177 uint64_t Signature = makeTypeSignature(Identifier);
2178 NewTU.setTypeSignature(Signature);
2180 if (useSplitDwarf())
2181 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2182 DwarfTypesDWOSectionSym);
2184 CU.applyStmtList(UnitDie);
2186 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2189 NewTU.setType(NewTU.createTypeDIE(CTy));
2192 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2193 TypeUnitsUnderConstruction.clear();
2195 // Types referencing entries in the address table cannot be placed in type
2197 if (AddrPool.hasBeenUsed()) {
2199 // Remove all the types built while building this type.
2200 // This is pessimistic as some of these types might not be dependent on
2201 // the type that used an address.
2202 for (const auto &TU : TypeUnitsToAdd)
2203 DwarfTypeUnits.erase(TU.second);
2205 // Construct this type in the CU directly.
2206 // This is inefficient because all the dependent types will be rebuilt
2207 // from scratch, including building them in type units, discovering that
2208 // they depend on addresses, throwing them out and rebuilding them.
2209 CU.constructTypeDIE(RefDie, CTy);
2213 // If the type wasn't dependent on fission addresses, finish adding the type
2214 // and all its dependent types.
2215 for (auto &TU : TypeUnitsToAdd)
2216 InfoHolder.addUnit(std::move(TU.first));
2218 CU.addDIETypeSignature(RefDie, NewTU);
2221 // Accelerator table mutators - add each name along with its companion
2222 // DIE to the proper table while ensuring that the name that we're going
2223 // to reference is in the string table. We do this since the names we
2224 // add may not only be identical to the names in the DIE.
2225 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2226 if (!useDwarfAccelTables())
2228 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2232 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2233 if (!useDwarfAccelTables())
2235 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2239 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2240 if (!useDwarfAccelTables())
2242 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2246 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2247 if (!useDwarfAccelTables())
2249 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),