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"
15 #include "ByteStreamer.h"
17 #include "DebugLocEntry.h"
18 #include "DwarfCompileUnit.h"
19 #include "DwarfExpression.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/DIE.h"
26 #include "llvm/CodeGen/MachineFunction.h"
27 #include "llvm/CodeGen/MachineModuleInfo.h"
28 #include "llvm/IR/Constants.h"
29 #include "llvm/IR/DIBuilder.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/Instructions.h"
33 #include "llvm/IR/Module.h"
34 #include "llvm/IR/ValueHandle.h"
35 #include "llvm/MC/MCAsmInfo.h"
36 #include "llvm/MC/MCSection.h"
37 #include "llvm/MC/MCStreamer.h"
38 #include "llvm/MC/MCSymbol.h"
39 #include "llvm/Support/CommandLine.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/Dwarf.h"
42 #include "llvm/Support/Endian.h"
43 #include "llvm/Support/ErrorHandling.h"
44 #include "llvm/Support/FormattedStream.h"
45 #include "llvm/Support/LEB128.h"
46 #include "llvm/Support/MD5.h"
47 #include "llvm/Support/Path.h"
48 #include "llvm/Support/Timer.h"
49 #include "llvm/Support/raw_ostream.h"
50 #include "llvm/Target/TargetFrameLowering.h"
51 #include "llvm/Target/TargetLoweringObjectFile.h"
52 #include "llvm/Target/TargetMachine.h"
53 #include "llvm/Target/TargetOptions.h"
54 #include "llvm/Target/TargetRegisterInfo.h"
55 #include "llvm/Target/TargetSubtargetInfo.h"
58 #define DEBUG_TYPE "dwarfdebug"
61 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
62 cl::desc("Disable debug info printing"));
64 static cl::opt<bool> UnknownLocations(
65 "use-unknown-locations", cl::Hidden,
66 cl::desc("Make an absence of debug location information explicit."),
70 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
71 cl::desc("Generate GNU-style pubnames and pubtypes"),
74 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
76 cl::desc("Generate dwarf aranges"),
80 enum DefaultOnOff { Default, Enable, Disable };
83 static cl::opt<DefaultOnOff>
84 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
85 cl::desc("Output prototype dwarf accelerator tables."),
86 cl::values(clEnumVal(Default, "Default for platform"),
87 clEnumVal(Enable, "Enabled"),
88 clEnumVal(Disable, "Disabled"), clEnumValEnd),
91 static cl::opt<DefaultOnOff>
92 SplitDwarf("split-dwarf", cl::Hidden,
93 cl::desc("Output DWARF5 split debug info."),
94 cl::values(clEnumVal(Default, "Default for platform"),
95 clEnumVal(Enable, "Enabled"),
96 clEnumVal(Disable, "Disabled"), clEnumValEnd),
99 static cl::opt<DefaultOnOff>
100 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
101 cl::desc("Generate DWARF pubnames and pubtypes sections"),
102 cl::values(clEnumVal(Default, "Default for platform"),
103 clEnumVal(Enable, "Enabled"),
104 clEnumVal(Disable, "Disabled"), clEnumValEnd),
107 static const char *const DWARFGroupName = "DWARF Emission";
108 static const char *const DbgTimerName = "DWARF Debug Writer";
110 void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) {
112 Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op)
113 : dwarf::OperationEncodingString(Op));
116 void DebugLocDwarfExpression::EmitSigned(int64_t Value) {
117 BS.EmitSLEB128(Value, Twine(Value));
120 void DebugLocDwarfExpression::EmitUnsigned(uint64_t Value) {
121 BS.EmitULEB128(Value, Twine(Value));
124 bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) {
125 // This information is not available while emitting .debug_loc entries.
129 //===----------------------------------------------------------------------===//
131 /// resolve - Look in the DwarfDebug map for the MDNode that
132 /// corresponds to the reference.
133 template <typename T> T *DbgVariable::resolve(TypedDINodeRef<T> Ref) const {
134 return DD->resolve(Ref);
137 bool DbgVariable::isBlockByrefVariable() const {
138 assert(Var && "Invalid complex DbgVariable!");
139 return Var->getType()
140 .resolve(DD->getTypeIdentifierMap())
141 ->isBlockByrefStruct();
144 const DIType *DbgVariable::getType() const {
145 DIType *Ty = Var->getType().resolve(DD->getTypeIdentifierMap());
146 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
147 // addresses instead.
148 if (Ty->isBlockByrefStruct()) {
149 /* Byref variables, in Blocks, are declared by the programmer as
150 "SomeType VarName;", but the compiler creates a
151 __Block_byref_x_VarName struct, and gives the variable VarName
152 either the struct, or a pointer to the struct, as its type. This
153 is necessary for various behind-the-scenes things the compiler
154 needs to do with by-reference variables in blocks.
156 However, as far as the original *programmer* is concerned, the
157 variable should still have type 'SomeType', as originally declared.
159 The following function dives into the __Block_byref_x_VarName
160 struct to find the original type of the variable. This will be
161 passed back to the code generating the type for the Debug
162 Information Entry for the variable 'VarName'. 'VarName' will then
163 have the original type 'SomeType' in its debug information.
165 The original type 'SomeType' will be the type of the field named
166 'VarName' inside the __Block_byref_x_VarName struct.
168 NOTE: In order for this to not completely fail on the debugger
169 side, the Debug Information Entry for the variable VarName needs to
170 have a DW_AT_location that tells the debugger how to unwind through
171 the pointers and __Block_byref_x_VarName struct to find the actual
172 value of the variable. The function addBlockByrefType does this. */
173 DIType *subType = Ty;
174 uint16_t tag = Ty->getTag();
176 if (tag == dwarf::DW_TAG_pointer_type)
177 subType = resolve(cast<DIDerivedType>(Ty)->getBaseType());
179 auto Elements = cast<DICompositeTypeBase>(subType)->getElements();
180 for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
181 auto *DT = cast<DIDerivedTypeBase>(Elements[i]);
182 if (getName() == DT->getName())
183 return resolve(DT->getBaseType());
189 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
190 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
191 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
192 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
194 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
195 : Asm(A), MMI(Asm->MMI), DebugLocs(A->OutStreamer->isVerboseAsm()),
196 PrevLabel(nullptr), InfoHolder(A, "info_string", DIEValueAllocator),
197 UsedNonDefaultText(false),
198 SkeletonHolder(A, "skel_string", DIEValueAllocator),
199 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
200 IsPS4(Triple(A->getTargetTriple()).isPS4()),
201 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
202 dwarf::DW_FORM_data4)),
203 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
204 dwarf::DW_FORM_data4)),
205 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
206 dwarf::DW_FORM_data4)),
207 AccelTypes(TypeAtoms) {
212 // Turn on accelerator tables for Darwin by default, pubnames by
213 // default for non-Darwin/PS4, and handle split dwarf.
214 if (DwarfAccelTables == Default)
215 HasDwarfAccelTables = IsDarwin;
217 HasDwarfAccelTables = DwarfAccelTables == Enable;
219 if (SplitDwarf == Default)
220 HasSplitDwarf = false;
222 HasSplitDwarf = SplitDwarf == Enable;
224 if (DwarfPubSections == Default)
225 HasDwarfPubSections = !IsDarwin && !IsPS4;
227 HasDwarfPubSections = DwarfPubSections == Enable;
229 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
230 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
231 : MMI->getModule()->getDwarfVersion();
233 // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3).
234 // Everybody else uses GNU's.
235 UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3;
237 Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion);
240 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
245 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
246 DwarfDebug::~DwarfDebug() { }
248 static bool isObjCClass(StringRef Name) {
249 return Name.startswith("+") || Name.startswith("-");
252 static bool hasObjCCategory(StringRef Name) {
253 if (!isObjCClass(Name))
256 return Name.find(") ") != StringRef::npos;
259 static void getObjCClassCategory(StringRef In, StringRef &Class,
260 StringRef &Category) {
261 if (!hasObjCCategory(In)) {
262 Class = In.slice(In.find('[') + 1, In.find(' '));
267 Class = In.slice(In.find('[') + 1, In.find('('));
268 Category = In.slice(In.find('[') + 1, In.find(' '));
272 static StringRef getObjCMethodName(StringRef In) {
273 return In.slice(In.find(' ') + 1, In.find(']'));
276 // Add the various names to the Dwarf accelerator table names.
277 // TODO: Determine whether or not we should add names for programs
278 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
279 // is only slightly different than the lookup of non-standard ObjC names.
280 void DwarfDebug::addSubprogramNames(const DISubprogram *SP, DIE &Die) {
281 if (!SP->isDefinition())
283 addAccelName(SP->getName(), Die);
285 // If the linkage name is different than the name, go ahead and output
286 // that as well into the name table.
287 if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName())
288 addAccelName(SP->getLinkageName(), Die);
290 // If this is an Objective-C selector name add it to the ObjC accelerator
292 if (isObjCClass(SP->getName())) {
293 StringRef Class, Category;
294 getObjCClassCategory(SP->getName(), Class, Category);
295 addAccelObjC(Class, Die);
297 addAccelObjC(Category, Die);
298 // Also add the base method name to the name table.
299 addAccelName(getObjCMethodName(SP->getName()), Die);
303 /// isSubprogramContext - Return true if Context is either a subprogram
304 /// or another context nested inside a subprogram.
305 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
308 if (isa<DISubprogram>(Context))
310 if (auto *T = dyn_cast<DIType>(Context))
311 return isSubprogramContext(resolve(T->getScope()));
315 /// Check whether we should create a DIE for the given Scope, return true
316 /// if we don't create a DIE (the corresponding DIE is null).
317 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
318 if (Scope->isAbstractScope())
321 // We don't create a DIE if there is no Range.
322 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
326 if (Ranges.size() > 1)
329 // We don't create a DIE if we have a single Range and the end label
331 return !getLabelAfterInsn(Ranges.front().second);
334 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
336 if (auto *SkelCU = CU.getSkeleton())
340 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
341 assert(Scope && Scope->getScopeNode());
342 assert(Scope->isAbstractScope());
343 assert(!Scope->getInlinedAt());
345 const MDNode *SP = Scope->getScopeNode();
347 ProcessedSPNodes.insert(SP);
349 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
350 // was inlined from another compile unit.
351 auto &CU = SPMap[SP];
352 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
353 CU.constructAbstractSubprogramScopeDIE(Scope);
357 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
358 if (!GenerateGnuPubSections)
361 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
364 // Create new DwarfCompileUnit for the given metadata node with tag
365 // DW_TAG_compile_unit.
367 DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) {
368 StringRef FN = DIUnit->getFilename();
369 CompilationDir = DIUnit->getDirectory();
371 auto OwnedUnit = make_unique<DwarfCompileUnit>(
372 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
373 DwarfCompileUnit &NewCU = *OwnedUnit;
374 DIE &Die = NewCU.getUnitDie();
375 InfoHolder.addUnit(std::move(OwnedUnit));
377 NewCU.setSkeleton(constructSkeletonCU(NewCU));
379 // LTO with assembly output shares a single line table amongst multiple CUs.
380 // To avoid the compilation directory being ambiguous, let the line table
381 // explicitly describe the directory of all files, never relying on the
382 // compilation directory.
383 if (!Asm->OutStreamer->hasRawTextSupport() || SingleCU)
384 Asm->OutStreamer->getContext().setMCLineTableCompilationDir(
385 NewCU.getUniqueID(), CompilationDir);
387 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer());
388 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
389 DIUnit->getSourceLanguage());
390 NewCU.addString(Die, dwarf::DW_AT_name, FN);
392 if (!useSplitDwarf()) {
393 NewCU.initStmtList();
395 // If we're using split dwarf the compilation dir is going to be in the
396 // skeleton CU and so we don't need to duplicate it here.
397 if (!CompilationDir.empty())
398 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
400 addGnuPubAttributes(NewCU, Die);
403 if (DIUnit->isOptimized())
404 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
406 StringRef Flags = DIUnit->getFlags();
408 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
410 if (unsigned RVer = DIUnit->getRuntimeVersion())
411 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
412 dwarf::DW_FORM_data1, RVer);
415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
417 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
419 CUMap.insert(std::make_pair(DIUnit, &NewCU));
420 CUDieMap.insert(std::make_pair(&Die, &NewCU));
424 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
425 const DIImportedEntity *N) {
426 if (DIE *D = TheCU.getOrCreateContextDIE(N->getScope()))
427 D->addChild(TheCU.constructImportedEntityDIE(N));
430 // Emit all Dwarf sections that should come prior to the content. Create
431 // global DIEs and emit initial debug info sections. This is invoked by
432 // the target AsmPrinter.
433 void DwarfDebug::beginModule() {
434 if (DisableDebugInfoPrinting)
437 const Module *M = MMI->getModule();
439 FunctionDIs = makeSubprogramMap(*M);
441 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
444 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
446 SingleCU = CU_Nodes->getNumOperands() == 1;
448 for (MDNode *N : CU_Nodes->operands()) {
449 auto *CUNode = cast<DICompileUnit>(N);
450 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
451 for (auto *IE : CUNode->getImportedEntities())
452 ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE));
453 // Stable sort to preserve the order of appearance of imported entities.
454 // This is to avoid out-of-order processing of interdependent declarations
455 // within the same scope, e.g. { namespace A = base; namespace B = A; }
456 std::stable_sort(ScopesWithImportedEntities.begin(),
457 ScopesWithImportedEntities.end(), less_first());
458 for (auto *GV : CUNode->getGlobalVariables())
459 CU.getOrCreateGlobalVariableDIE(GV);
460 for (auto *SP : CUNode->getSubprograms())
461 SPMap.insert(std::make_pair(SP, &CU));
462 for (auto *Ty : CUNode->getEnumTypes()) {
463 // The enum types array by design contains pointers to
464 // MDNodes rather than DIRefs. Unique them here.
465 CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef())));
467 for (auto *Ty : CUNode->getRetainedTypes()) {
468 // The retained types array by design contains pointers to
469 // MDNodes rather than DIRefs. Unique them here.
470 CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef())));
472 // Emit imported_modules last so that the relevant context is already
474 for (auto *IE : CUNode->getImportedEntities())
475 constructAndAddImportedEntityDIE(CU, IE);
478 // Tell MMI that we have debug info.
479 MMI->setDebugInfoAvailability(true);
482 void DwarfDebug::finishVariableDefinitions() {
483 for (const auto &Var : ConcreteVariables) {
484 DIE *VariableDie = Var->getDIE();
486 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
487 // in the ConcreteVariables list, rather than looking it up again here.
488 // DIE::getUnit isn't simple - it walks parent pointers, etc.
489 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
491 DbgVariable *AbsVar = getExistingAbstractVariable(
492 InlinedVariable(Var->getVariable(), Var->getInlinedAt()));
493 if (AbsVar && AbsVar->getDIE()) {
494 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
497 Unit->applyVariableAttributes(*Var, *VariableDie);
501 void DwarfDebug::finishSubprogramDefinitions() {
502 for (const auto &P : SPMap)
503 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
504 CU.finishSubprogramDefinition(cast<DISubprogram>(P.first));
509 // Collect info for variables that were optimized out.
510 void DwarfDebug::collectDeadVariables() {
511 const Module *M = MMI->getModule();
513 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
514 for (MDNode *N : CU_Nodes->operands()) {
515 auto *TheCU = cast<DICompileUnit>(N);
516 // Construct subprogram DIE and add variables DIEs.
517 DwarfCompileUnit *SPCU =
518 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
519 assert(SPCU && "Unable to find Compile Unit!");
520 for (auto *SP : TheCU->getSubprograms()) {
521 if (ProcessedSPNodes.count(SP) != 0)
523 SPCU->collectDeadVariables(SP);
529 void DwarfDebug::finalizeModuleInfo() {
530 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
532 finishSubprogramDefinitions();
534 finishVariableDefinitions();
536 // Collect info for variables that were optimized out.
537 collectDeadVariables();
539 // Handle anything that needs to be done on a per-unit basis after
540 // all other generation.
541 for (const auto &P : CUMap) {
542 auto &TheCU = *P.second;
543 // Emit DW_AT_containing_type attribute to connect types with their
544 // vtable holding type.
545 TheCU.constructContainingTypeDIEs();
547 // Add CU specific attributes if we need to add any.
548 // If we're splitting the dwarf out now that we've got the entire
549 // CU then add the dwo id to it.
550 auto *SkCU = TheCU.getSkeleton();
551 if (useSplitDwarf()) {
552 // Emit a unique identifier for this CU.
553 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
554 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
555 dwarf::DW_FORM_data8, ID);
556 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
557 dwarf::DW_FORM_data8, ID);
559 // We don't keep track of which addresses are used in which CU so this
560 // is a bit pessimistic under LTO.
561 if (!AddrPool.isEmpty()) {
562 const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol();
563 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
566 if (!SkCU->getRangeLists().empty()) {
567 const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol();
568 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
573 // If we have code split among multiple sections or non-contiguous
574 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
575 // remain in the .o file, otherwise add a DW_AT_low_pc.
576 // FIXME: We should use ranges allow reordering of code ala
577 // .subsections_via_symbols in mach-o. This would mean turning on
578 // ranges for all subprogram DIEs for mach-o.
579 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
580 if (unsigned NumRanges = TheCU.getRanges().size()) {
582 // A DW_AT_low_pc attribute may also be specified in combination with
583 // DW_AT_ranges to specify the default base address for use in
584 // location lists (see Section 2.6.2) and range lists (see Section
586 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
588 U.setBaseAddress(TheCU.getRanges().front().getStart());
589 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
593 // Compute DIE offsets and sizes.
594 InfoHolder.computeSizeAndOffsets();
596 SkeletonHolder.computeSizeAndOffsets();
599 // Emit all Dwarf sections that should come after the content.
600 void DwarfDebug::endModule() {
601 assert(CurFn == nullptr);
602 assert(CurMI == nullptr);
604 // If we aren't actually generating debug info (check beginModule -
605 // conditionalized on !DisableDebugInfoPrinting and the presence of the
606 // llvm.dbg.cu metadata node)
607 if (!MMI->hasDebugInfo())
610 // Finalize the debug info for the module.
611 finalizeModuleInfo();
618 // Emit info into a debug loc section.
621 // Corresponding abbreviations into a abbrev section.
624 // Emit all the DIEs into a debug info section.
627 // Emit info into a debug aranges section.
628 if (GenerateARangeSection)
631 // Emit info into a debug ranges section.
634 if (useSplitDwarf()) {
637 emitDebugAbbrevDWO();
639 // Emit DWO addresses.
640 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
643 // Emit info into the dwarf accelerator table sections.
644 if (useDwarfAccelTables()) {
647 emitAccelNamespaces();
651 // Emit the pubnames and pubtypes sections if requested.
652 if (HasDwarfPubSections) {
653 emitDebugPubNames(GenerateGnuPubSections);
654 emitDebugPubTypes(GenerateGnuPubSections);
659 AbstractVariables.clear();
662 // Find abstract variable, if any, associated with Var.
664 DwarfDebug::getExistingAbstractVariable(InlinedVariable IV,
665 const DILocalVariable *&Cleansed) {
666 // More then one inlined variable corresponds to one abstract variable.
668 auto I = AbstractVariables.find(Cleansed);
669 if (I != AbstractVariables.end())
670 return I->second.get();
674 DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV) {
675 const DILocalVariable *Cleansed;
676 return getExistingAbstractVariable(IV, Cleansed);
679 void DwarfDebug::createAbstractVariable(const DILocalVariable *Var,
680 LexicalScope *Scope) {
681 auto AbsDbgVariable =
682 make_unique<DbgVariable>(Var, /* IA */ nullptr, /* Expr */ nullptr, this);
683 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
684 AbstractVariables[Var] = std::move(AbsDbgVariable);
687 void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV,
688 const MDNode *ScopeNode) {
689 const DILocalVariable *Cleansed = nullptr;
690 if (getExistingAbstractVariable(IV, Cleansed))
693 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(
694 cast<DILocalScope>(ScopeNode)));
697 void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(
698 InlinedVariable IV, const MDNode *ScopeNode) {
699 const DILocalVariable *Cleansed = nullptr;
700 if (getExistingAbstractVariable(IV, Cleansed))
703 if (LexicalScope *Scope =
704 LScopes.findAbstractScope(cast_or_null<DILocalScope>(ScopeNode)))
705 createAbstractVariable(Cleansed, Scope);
708 // Collect variable information from side table maintained by MMI.
709 void DwarfDebug::collectVariableInfoFromMMITable(
710 DenseSet<InlinedVariable> &Processed) {
711 for (const auto &VI : MMI->getVariableDbgInfo()) {
714 assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
715 "Expected inlined-at fields to agree");
717 InlinedVariable Var(VI.Var, VI.Loc->getInlinedAt());
718 Processed.insert(Var);
719 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
721 // If variable scope is not found then skip this variable.
725 const DIExpression *Expr = cast_or_null<DIExpression>(VI.Expr);
726 ensureAbstractVariableIsCreatedIfScoped(Var, Scope->getScopeNode());
728 make_unique<DbgVariable>(Var.first, Var.second, Expr, this, VI.Slot);
729 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
730 ConcreteVariables.push_back(std::move(RegVar));
734 // Get .debug_loc entry for the instruction range starting at MI.
735 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
736 const DIExpression *Expr = MI->getDebugExpression();
738 assert(MI->getNumOperands() == 4);
739 if (MI->getOperand(0).isReg()) {
740 MachineLocation MLoc;
741 // If the second operand is an immediate, this is a
742 // register-indirect address.
743 if (!MI->getOperand(1).isImm())
744 MLoc.set(MI->getOperand(0).getReg());
746 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
747 return DebugLocEntry::Value(Expr, MLoc);
749 if (MI->getOperand(0).isImm())
750 return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm());
751 if (MI->getOperand(0).isFPImm())
752 return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm());
753 if (MI->getOperand(0).isCImm())
754 return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm());
756 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
759 /// Determine whether two variable pieces overlap.
760 static bool piecesOverlap(const DIExpression *P1, const DIExpression *P2) {
761 if (!P1->isBitPiece() || !P2->isBitPiece())
763 unsigned l1 = P1->getBitPieceOffset();
764 unsigned l2 = P2->getBitPieceOffset();
765 unsigned r1 = l1 + P1->getBitPieceSize();
766 unsigned r2 = l2 + P2->getBitPieceSize();
767 // True where [l1,r1[ and [r1,r2[ overlap.
768 return (l1 < r2) && (l2 < r1);
771 /// Build the location list for all DBG_VALUEs in the function that
772 /// describe the same variable. If the ranges of several independent
773 /// pieces of the same variable overlap partially, split them up and
774 /// combine the ranges. The resulting DebugLocEntries are will have
775 /// strict monotonically increasing begin addresses and will never
780 // Ranges History [var, loc, piece ofs size]
781 // 0 | [x, (reg0, piece 0, 32)]
782 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
784 // 3 | [clobber reg0]
785 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
790 // [0-1] [x, (reg0, piece 0, 32)]
791 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
792 // [3-4] [x, (reg1, piece 32, 32)]
793 // [4- ] [x, (mem, piece 0, 64)]
795 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
796 const DbgValueHistoryMap::InstrRanges &Ranges) {
797 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
799 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
800 const MachineInstr *Begin = I->first;
801 const MachineInstr *End = I->second;
802 assert(Begin->isDebugValue() && "Invalid History entry");
804 // Check if a variable is inaccessible in this range.
805 if (Begin->getNumOperands() > 1 &&
806 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
811 // If this piece overlaps with any open ranges, truncate them.
812 const DIExpression *DIExpr = Begin->getDebugExpression();
813 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
814 [&](DebugLocEntry::Value R) {
815 return piecesOverlap(DIExpr, R.getExpression());
817 OpenRanges.erase(Last, OpenRanges.end());
819 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
820 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
822 const MCSymbol *EndLabel;
824 EndLabel = getLabelAfterInsn(End);
825 else if (std::next(I) == Ranges.end())
826 EndLabel = Asm->getFunctionEnd();
828 EndLabel = getLabelBeforeInsn(std::next(I)->first);
829 assert(EndLabel && "Forgot label after instruction ending a range!");
831 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
833 auto Value = getDebugLocValue(Begin);
834 DebugLocEntry Loc(StartLabel, EndLabel, Value);
835 bool couldMerge = false;
837 // If this is a piece, it may belong to the current DebugLocEntry.
838 if (DIExpr->isBitPiece()) {
839 // Add this value to the list of open ranges.
840 OpenRanges.push_back(Value);
842 // Attempt to add the piece to the last entry.
843 if (!DebugLoc.empty())
844 if (DebugLoc.back().MergeValues(Loc))
849 // Need to add a new DebugLocEntry. Add all values from still
850 // valid non-overlapping pieces.
851 if (OpenRanges.size())
852 Loc.addValues(OpenRanges);
854 DebugLoc.push_back(std::move(Loc));
857 // Attempt to coalesce the ranges of two otherwise identical
859 auto CurEntry = DebugLoc.rbegin();
861 dbgs() << CurEntry->getValues().size() << " Values:\n";
862 for (auto &Value : CurEntry->getValues())
863 Value.getExpression()->dump();
867 auto PrevEntry = std::next(CurEntry);
868 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
874 // Find variables for each lexical scope.
875 void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU,
876 const DISubprogram *SP,
877 DenseSet<InlinedVariable> &Processed) {
878 // Grab the variable info that was squirreled away in the MMI side-table.
879 collectVariableInfoFromMMITable(Processed);
881 for (const auto &I : DbgValues) {
882 InlinedVariable IV = I.first;
883 if (Processed.count(IV))
886 // Instruction ranges, specifying where IV is accessible.
887 const auto &Ranges = I.second;
891 LexicalScope *Scope = nullptr;
892 if (const DILocation *IA = IV.second)
893 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA);
895 Scope = LScopes.findLexicalScope(IV.first->getScope());
896 // If variable scope is not found then skip this variable.
900 Processed.insert(IV);
901 const MachineInstr *MInsn = Ranges.front().first;
902 assert(MInsn->isDebugValue() && "History must begin with debug value");
903 ensureAbstractVariableIsCreatedIfScoped(IV, Scope->getScopeNode());
904 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
905 DbgVariable *RegVar = ConcreteVariables.back().get();
906 InfoHolder.addScopeVariable(Scope, RegVar);
908 // Check if the first DBG_VALUE is valid for the rest of the function.
909 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
912 // Handle multiple DBG_VALUE instructions describing one variable.
913 RegVar->setDebugLocListIndex(
914 DebugLocs.startList(&TheCU, Asm->createTempSymbol("debug_loc")));
916 // Build the location list for this variable.
917 SmallVector<DebugLocEntry, 8> Entries;
918 buildLocationList(Entries, Ranges);
920 // If the variable has an DIBasicType, extract it. Basic types cannot have
921 // unique identifiers, so don't bother resolving the type with the
923 const DIBasicType *BT = dyn_cast<DIBasicType>(
924 static_cast<const Metadata *>(IV.first->getType()));
926 // Finalize the entry by lowering it into a DWARF bytestream.
927 for (auto &Entry : Entries)
928 Entry.finalize(*Asm, DebugLocs, BT);
931 // Collect info for variables that were optimized out.
932 for (const DILocalVariable *DV : SP->getVariables()) {
933 if (!Processed.insert(InlinedVariable(DV, nullptr)).second)
935 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) {
936 ensureAbstractVariableIsCreatedIfScoped(InlinedVariable(DV, nullptr),
937 Scope->getScopeNode());
938 ConcreteVariables.push_back(make_unique<DbgVariable>(
939 DV, /* IA */ nullptr, /* Expr */ nullptr, this));
940 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
945 // Return Label preceding the instruction.
946 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
947 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
948 assert(Label && "Didn't insert label before instruction");
952 // Return Label immediately following the instruction.
953 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
954 return LabelsAfterInsn.lookup(MI);
957 // Process beginning of an instruction.
958 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
959 assert(CurMI == nullptr);
961 // Check if source location changes, but ignore DBG_VALUE locations.
962 if (!MI->isDebugValue()) {
963 DebugLoc DL = MI->getDebugLoc();
964 if (DL != PrevInstLoc) {
968 if (DL == PrologEndLoc) {
969 Flags |= DWARF2_FLAG_PROLOGUE_END;
970 PrologEndLoc = DebugLoc();
971 Flags |= DWARF2_FLAG_IS_STMT;
974 Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine())
975 Flags |= DWARF2_FLAG_IS_STMT;
977 const MDNode *Scope = DL.getScope();
978 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
979 } else if (UnknownLocations) {
981 recordSourceLine(0, 0, nullptr, 0);
986 // Insert labels where requested.
987 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
988 LabelsBeforeInsn.find(MI);
991 if (I == LabelsBeforeInsn.end())
994 // Label already assigned.
999 PrevLabel = MMI->getContext().createTempSymbol();
1000 Asm->OutStreamer->EmitLabel(PrevLabel);
1002 I->second = PrevLabel;
1005 // Process end of an instruction.
1006 void DwarfDebug::endInstruction() {
1007 assert(CurMI != nullptr);
1008 // Don't create a new label after DBG_VALUE instructions.
1009 // They don't generate code.
1010 if (!CurMI->isDebugValue())
1011 PrevLabel = nullptr;
1013 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1014 LabelsAfterInsn.find(CurMI);
1018 if (I == LabelsAfterInsn.end())
1021 // Label already assigned.
1025 // We need a label after this instruction.
1027 PrevLabel = MMI->getContext().createTempSymbol();
1028 Asm->OutStreamer->EmitLabel(PrevLabel);
1030 I->second = PrevLabel;
1033 // Each LexicalScope has first instruction and last instruction to mark
1034 // beginning and end of a scope respectively. Create an inverse map that list
1035 // scopes starts (and ends) with an instruction. One instruction may start (or
1036 // end) multiple scopes. Ignore scopes that are not reachable.
1037 void DwarfDebug::identifyScopeMarkers() {
1038 SmallVector<LexicalScope *, 4> WorkList;
1039 WorkList.push_back(LScopes.getCurrentFunctionScope());
1040 while (!WorkList.empty()) {
1041 LexicalScope *S = WorkList.pop_back_val();
1043 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1044 if (!Children.empty())
1045 WorkList.append(Children.begin(), Children.end());
1047 if (S->isAbstractScope())
1050 for (const InsnRange &R : S->getRanges()) {
1051 assert(R.first && "InsnRange does not have first instruction!");
1052 assert(R.second && "InsnRange does not have second instruction!");
1053 requestLabelBeforeInsn(R.first);
1054 requestLabelAfterInsn(R.second);
1059 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1060 // First known non-DBG_VALUE and non-frame setup location marks
1061 // the beginning of the function body.
1062 for (const auto &MBB : *MF)
1063 for (const auto &MI : MBB)
1064 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1066 // Did the target forget to set the FrameSetup flag for CFI insns?
1067 assert(!MI.isCFIInstruction() &&
1068 "First non-frame-setup instruction is a CFI instruction.");
1069 return MI.getDebugLoc();
1074 // Gather pre-function debug information. Assumes being called immediately
1075 // after the function entry point has been emitted.
1076 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1079 // If there's no debug info for the function we're not going to do anything.
1080 if (!MMI->hasDebugInfo())
1083 auto DI = FunctionDIs.find(MF->getFunction());
1084 if (DI == FunctionDIs.end())
1087 // Grab the lexical scopes for the function, if we don't have any of those
1088 // then we're not going to be able to do anything.
1089 LScopes.initialize(*MF);
1090 if (LScopes.empty())
1093 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1095 // Make sure that each lexical scope will have a begin/end label.
1096 identifyScopeMarkers();
1098 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1099 // belongs to so that we add to the correct per-cu line table in the
1101 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1102 // FnScope->getScopeNode() and DI->second should represent the same function,
1103 // though they may not be the same MDNode due to inline functions merged in
1104 // LTO where the debug info metadata still differs (either due to distinct
1105 // written differences - two versions of a linkonce_odr function
1106 // written/copied into two separate files, or some sub-optimal metadata that
1107 // isn't structurally identical (see: file path/name info from clang, which
1108 // includes the directory of the cpp file being built, even when the file name
1109 // is absolute (such as an <> lookup header)))
1110 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1111 assert(TheCU && "Unable to find compile unit!");
1112 if (Asm->OutStreamer->hasRawTextSupport())
1113 // Use a single line table if we are generating assembly.
1114 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
1116 Asm->OutStreamer->getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1118 // Calculate history for local variables.
1119 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1122 // Request labels for the full history.
1123 for (const auto &I : DbgValues) {
1124 const auto &Ranges = I.second;
1128 // The first mention of a function argument gets the CurrentFnBegin
1129 // label, so arguments are visible when breaking at function entry.
1130 const DILocalVariable *DIVar = Ranges.front().first->getDebugVariable();
1131 if (DIVar->getTag() == dwarf::DW_TAG_arg_variable &&
1132 getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) {
1133 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin();
1134 if (Ranges.front().first->getDebugExpression()->isBitPiece()) {
1135 // Mark all non-overlapping initial pieces.
1136 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1137 const DIExpression *Piece = I->first->getDebugExpression();
1138 if (std::all_of(Ranges.begin(), I,
1139 [&](DbgValueHistoryMap::InstrRange Pred) {
1140 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1142 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
1149 for (const auto &Range : Ranges) {
1150 requestLabelBeforeInsn(Range.first);
1152 requestLabelAfterInsn(Range.second);
1156 PrevInstLoc = DebugLoc();
1157 PrevLabel = Asm->getFunctionBegin();
1159 // Record beginning of function.
1160 PrologEndLoc = findPrologueEndLoc(MF);
1161 if (DILocation *L = PrologEndLoc) {
1162 // We'd like to list the prologue as "not statements" but GDB behaves
1163 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1164 auto *SP = L->getInlinedAtScope()->getSubprogram();
1165 recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT);
1169 // Gather and emit post-function debug information.
1170 void DwarfDebug::endFunction(const MachineFunction *MF) {
1171 assert(CurFn == MF &&
1172 "endFunction should be called with the same function as beginFunction");
1174 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1175 !FunctionDIs.count(MF->getFunction())) {
1176 // If we don't have a lexical scope for this function then there will
1177 // be a hole in the range information. Keep note of this by setting the
1178 // previously used section to nullptr.
1184 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1185 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
1187 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1188 auto *SP = cast<DISubprogram>(FnScope->getScopeNode());
1189 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1191 DenseSet<InlinedVariable> ProcessedVars;
1192 collectVariableInfo(TheCU, SP, ProcessedVars);
1194 // Add the range of this function to the list of ranges for the CU.
1195 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd()));
1197 // Under -gmlt, skip building the subprogram if there are no inlined
1198 // subroutines inside it.
1199 if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly &&
1200 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1201 assert(InfoHolder.getScopeVariables().empty());
1202 assert(DbgValues.empty());
1203 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1204 // by a -gmlt CU. Add a test and remove this assertion.
1205 assert(AbstractVariables.empty());
1206 LabelsBeforeInsn.clear();
1207 LabelsAfterInsn.clear();
1208 PrevLabel = nullptr;
1214 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1216 // Construct abstract scopes.
1217 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1218 auto *SP = cast<DISubprogram>(AScope->getScopeNode());
1219 // Collect info for variables that were optimized out.
1220 for (const DILocalVariable *DV : SP->getVariables()) {
1221 if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second)
1223 ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr),
1225 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1226 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1228 constructAbstractSubprogramScopeDIE(AScope);
1231 TheCU.constructSubprogramScopeDIE(FnScope);
1232 if (auto *SkelCU = TheCU.getSkeleton())
1233 if (!LScopes.getAbstractScopesList().empty())
1234 SkelCU->constructSubprogramScopeDIE(FnScope);
1237 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1238 // DbgVariables except those that are also in AbstractVariables (since they
1239 // can be used cross-function)
1240 InfoHolder.getScopeVariables().clear();
1242 LabelsBeforeInsn.clear();
1243 LabelsAfterInsn.clear();
1244 PrevLabel = nullptr;
1248 // Register a source line with debug info. Returns the unique label that was
1249 // emitted and which provides correspondence to the source line list.
1250 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1255 unsigned Discriminator = 0;
1256 if (auto *Scope = cast_or_null<DIScope>(S)) {
1257 Fn = Scope->getFilename();
1258 Dir = Scope->getDirectory();
1259 if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
1260 Discriminator = LBF->getDiscriminator();
1262 unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();
1263 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1264 .getOrCreateSourceID(Fn, Dir);
1266 Asm->OutStreamer->EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1270 //===----------------------------------------------------------------------===//
1272 //===----------------------------------------------------------------------===//
1274 // Emit the debug info section.
1275 void DwarfDebug::emitDebugInfo() {
1276 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1277 Holder.emitUnits(/* UseOffsets */ false);
1280 // Emit the abbreviation section.
1281 void DwarfDebug::emitAbbreviations() {
1282 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1284 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1287 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, MCSection *Section,
1288 StringRef TableName) {
1289 Accel.FinalizeTable(Asm, TableName);
1290 Asm->OutStreamer->SwitchSection(Section);
1292 // Emit the full data.
1293 Accel.emit(Asm, Section->getBeginSymbol(), this);
1296 // Emit visible names into a hashed accelerator table section.
1297 void DwarfDebug::emitAccelNames() {
1298 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1302 // Emit objective C classes and categories into a hashed accelerator table
1304 void DwarfDebug::emitAccelObjC() {
1305 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1309 // Emit namespace dies into a hashed accelerator table.
1310 void DwarfDebug::emitAccelNamespaces() {
1311 emitAccel(AccelNamespace,
1312 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1316 // Emit type dies into a hashed accelerator table.
1317 void DwarfDebug::emitAccelTypes() {
1318 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1322 // Public name handling.
1323 // The format for the various pubnames:
1325 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1326 // for the DIE that is named.
1328 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1329 // into the CU and the index value is computed according to the type of value
1330 // for the DIE that is named.
1332 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1333 // it's the offset within the debug_info/debug_types dwo section, however, the
1334 // reference in the pubname header doesn't change.
1336 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1337 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1339 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1341 // We could have a specification DIE that has our most of our knowledge,
1342 // look for that now.
1343 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1345 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1346 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1347 Linkage = dwarf::GIEL_EXTERNAL;
1348 } else if (Die->findAttribute(dwarf::DW_AT_external))
1349 Linkage = dwarf::GIEL_EXTERNAL;
1351 switch (Die->getTag()) {
1352 case dwarf::DW_TAG_class_type:
1353 case dwarf::DW_TAG_structure_type:
1354 case dwarf::DW_TAG_union_type:
1355 case dwarf::DW_TAG_enumeration_type:
1356 return dwarf::PubIndexEntryDescriptor(
1357 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1358 ? dwarf::GIEL_STATIC
1359 : dwarf::GIEL_EXTERNAL);
1360 case dwarf::DW_TAG_typedef:
1361 case dwarf::DW_TAG_base_type:
1362 case dwarf::DW_TAG_subrange_type:
1363 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1364 case dwarf::DW_TAG_namespace:
1365 return dwarf::GIEK_TYPE;
1366 case dwarf::DW_TAG_subprogram:
1367 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1368 case dwarf::DW_TAG_variable:
1369 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1370 case dwarf::DW_TAG_enumerator:
1371 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1372 dwarf::GIEL_STATIC);
1374 return dwarf::GIEK_NONE;
1378 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1380 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1381 MCSection *PSec = GnuStyle
1382 ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1383 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1385 emitDebugPubSection(GnuStyle, PSec, "Names",
1386 &DwarfCompileUnit::getGlobalNames);
1389 void DwarfDebug::emitDebugPubSection(
1390 bool GnuStyle, MCSection *PSec, StringRef Name,
1391 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1392 for (const auto &NU : CUMap) {
1393 DwarfCompileUnit *TheU = NU.second;
1395 const auto &Globals = (TheU->*Accessor)();
1397 if (Globals.empty())
1400 if (auto *Skeleton = TheU->getSkeleton())
1403 // Start the dwarf pubnames section.
1404 Asm->OutStreamer->SwitchSection(PSec);
1407 Asm->OutStreamer->AddComment("Length of Public " + Name + " Info");
1408 MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin");
1409 MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end");
1410 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1412 Asm->OutStreamer->EmitLabel(BeginLabel);
1414 Asm->OutStreamer->AddComment("DWARF Version");
1415 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1417 Asm->OutStreamer->AddComment("Offset of Compilation Unit Info");
1418 Asm->emitSectionOffset(TheU->getLabelBegin());
1420 Asm->OutStreamer->AddComment("Compilation Unit Length");
1421 Asm->EmitInt32(TheU->getLength());
1423 // Emit the pubnames for this compilation unit.
1424 for (const auto &GI : Globals) {
1425 const char *Name = GI.getKeyData();
1426 const DIE *Entity = GI.second;
1428 Asm->OutStreamer->AddComment("DIE offset");
1429 Asm->EmitInt32(Entity->getOffset());
1432 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1433 Asm->OutStreamer->AddComment(
1434 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1435 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1436 Asm->EmitInt8(Desc.toBits());
1439 Asm->OutStreamer->AddComment("External Name");
1440 Asm->OutStreamer->EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1443 Asm->OutStreamer->AddComment("End Mark");
1445 Asm->OutStreamer->EmitLabel(EndLabel);
1449 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1450 MCSection *PSec = GnuStyle
1451 ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1452 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1454 emitDebugPubSection(GnuStyle, PSec, "Types",
1455 &DwarfCompileUnit::getGlobalTypes);
1458 // Emit visible names into a debug str section.
1459 void DwarfDebug::emitDebugStr() {
1460 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1461 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1464 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1465 const DebugLocStream::Entry &Entry) {
1466 auto &&Comments = DebugLocs.getComments(Entry);
1467 auto Comment = Comments.begin();
1468 auto End = Comments.end();
1469 for (uint8_t Byte : DebugLocs.getBytes(Entry))
1470 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1473 static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
1474 ByteStreamer &Streamer,
1475 const DebugLocEntry::Value &Value,
1476 unsigned PieceOffsetInBits) {
1477 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(),
1478 AP.getDwarfDebug()->getDwarfVersion(),
1481 if (Value.isInt()) {
1482 if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed ||
1483 BT->getEncoding() == dwarf::DW_ATE_signed_char))
1484 DwarfExpr.AddSignedConstant(Value.getInt());
1486 DwarfExpr.AddUnsignedConstant(Value.getInt());
1487 } else if (Value.isLocation()) {
1488 MachineLocation Loc = Value.getLoc();
1489 const DIExpression *Expr = Value.getExpression();
1490 if (!Expr || !Expr->getNumElements())
1492 AP.EmitDwarfRegOp(Streamer, Loc);
1494 // Complex address entry.
1495 if (Loc.getOffset()) {
1496 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1497 DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(),
1500 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1504 // else ... ignore constant fp. There is not any good way to
1505 // to represent them here in dwarf.
1509 void DebugLocEntry::finalize(const AsmPrinter &AP, DebugLocStream &Locs,
1510 const DIBasicType *BT) {
1511 Locs.startEntry(Begin, End);
1512 BufferByteStreamer Streamer = Locs.getStreamer();
1513 const DebugLocEntry::Value &Value = Values[0];
1514 if (Value.isBitPiece()) {
1515 // Emit all pieces that belong to the same variable and range.
1516 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1517 return P.isBitPiece();
1518 }) && "all values are expected to be pieces");
1519 assert(std::is_sorted(Values.begin(), Values.end()) &&
1520 "pieces are expected to be sorted");
1522 unsigned Offset = 0;
1523 for (auto Piece : Values) {
1524 const DIExpression *Expr = Piece.getExpression();
1525 unsigned PieceOffset = Expr->getBitPieceOffset();
1526 unsigned PieceSize = Expr->getBitPieceSize();
1527 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1528 if (Offset < PieceOffset) {
1529 // The DWARF spec seriously mandates pieces with no locations for gaps.
1530 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(),
1531 AP.getDwarfDebug()->getDwarfVersion(),
1533 Expr.AddOpPiece(PieceOffset-Offset, 0);
1534 Offset += PieceOffset-Offset;
1536 Offset += PieceSize;
1538 emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset);
1541 assert(Values.size() == 1 && "only pieces may have >1 value");
1542 emitDebugLocValue(AP, BT, Streamer, Value, 0);
1546 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) {
1548 Asm->OutStreamer->AddComment("Loc expr size");
1549 Asm->EmitInt16(DebugLocs.getBytes(Entry).size());
1552 APByteStreamer Streamer(*Asm);
1553 emitDebugLocEntry(Streamer, Entry);
1556 // Emit locations into the debug loc section.
1557 void DwarfDebug::emitDebugLoc() {
1558 // Start the dwarf loc section.
1559 Asm->OutStreamer->SwitchSection(
1560 Asm->getObjFileLowering().getDwarfLocSection());
1561 unsigned char Size = Asm->getDataLayout().getPointerSize();
1562 for (const auto &List : DebugLocs.getLists()) {
1563 Asm->OutStreamer->EmitLabel(List.Label);
1564 const DwarfCompileUnit *CU = List.CU;
1565 for (const auto &Entry : DebugLocs.getEntries(List)) {
1566 // Set up the range. This range is relative to the entry point of the
1567 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1568 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1569 if (auto *Base = CU->getBaseAddress()) {
1570 Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
1571 Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
1573 Asm->OutStreamer->EmitSymbolValue(Entry.BeginSym, Size);
1574 Asm->OutStreamer->EmitSymbolValue(Entry.EndSym, Size);
1577 emitDebugLocEntryLocation(Entry);
1579 Asm->OutStreamer->EmitIntValue(0, Size);
1580 Asm->OutStreamer->EmitIntValue(0, Size);
1584 void DwarfDebug::emitDebugLocDWO() {
1585 Asm->OutStreamer->SwitchSection(
1586 Asm->getObjFileLowering().getDwarfLocDWOSection());
1587 for (const auto &List : DebugLocs.getLists()) {
1588 Asm->OutStreamer->EmitLabel(List.Label);
1589 for (const auto &Entry : DebugLocs.getEntries(List)) {
1590 // Just always use start_length for now - at least that's one address
1591 // rather than two. We could get fancier and try to, say, reuse an
1592 // address we know we've emitted elsewhere (the start of the function?
1593 // The start of the CU or CU subrange that encloses this range?)
1594 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1595 unsigned idx = AddrPool.getIndex(Entry.BeginSym);
1596 Asm->EmitULEB128(idx);
1597 Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4);
1599 emitDebugLocEntryLocation(Entry);
1601 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1606 const MCSymbol *Start, *End;
1609 // Emit a debug aranges section, containing a CU lookup for any
1610 // address we can tie back to a CU.
1611 void DwarfDebug::emitDebugARanges() {
1612 // Provides a unique id per text section.
1613 MapVector<MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1615 // Filter labels by section.
1616 for (const SymbolCU &SCU : ArangeLabels) {
1617 if (SCU.Sym->isInSection()) {
1618 // Make a note of this symbol and it's section.
1619 MCSection *Section = &SCU.Sym->getSection();
1620 if (!Section->getKind().isMetadata())
1621 SectionMap[Section].push_back(SCU);
1623 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1624 // appear in the output. This sucks as we rely on sections to build
1625 // arange spans. We can do it without, but it's icky.
1626 SectionMap[nullptr].push_back(SCU);
1630 // Add terminating symbols for each section.
1631 for (const auto &I : SectionMap) {
1632 MCSection *Section = I.first;
1633 MCSymbol *Sym = nullptr;
1636 Sym = Asm->OutStreamer->endSection(Section);
1638 // Insert a final terminator.
1639 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1642 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1644 for (auto &I : SectionMap) {
1645 const MCSection *Section = I.first;
1646 SmallVector<SymbolCU, 8> &List = I.second;
1647 if (List.size() < 2)
1650 // If we have no section (e.g. common), just write out
1651 // individual spans for each symbol.
1653 for (const SymbolCU &Cur : List) {
1655 Span.Start = Cur.Sym;
1658 Spans[Cur.CU].push_back(Span);
1663 // Sort the symbols by offset within the section.
1664 std::sort(List.begin(), List.end(),
1665 [&](const SymbolCU &A, const SymbolCU &B) {
1666 unsigned IA = A.Sym ? Asm->OutStreamer->GetSymbolOrder(A.Sym) : 0;
1667 unsigned IB = B.Sym ? Asm->OutStreamer->GetSymbolOrder(B.Sym) : 0;
1669 // Symbols with no order assigned should be placed at the end.
1670 // (e.g. section end labels)
1678 // Build spans between each label.
1679 const MCSymbol *StartSym = List[0].Sym;
1680 for (size_t n = 1, e = List.size(); n < e; n++) {
1681 const SymbolCU &Prev = List[n - 1];
1682 const SymbolCU &Cur = List[n];
1684 // Try and build the longest span we can within the same CU.
1685 if (Cur.CU != Prev.CU) {
1687 Span.Start = StartSym;
1689 Spans[Prev.CU].push_back(Span);
1695 // Start the dwarf aranges section.
1696 Asm->OutStreamer->SwitchSection(
1697 Asm->getObjFileLowering().getDwarfARangesSection());
1699 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1701 // Build a list of CUs used.
1702 std::vector<DwarfCompileUnit *> CUs;
1703 for (const auto &it : Spans) {
1704 DwarfCompileUnit *CU = it.first;
1708 // Sort the CU list (again, to ensure consistent output order).
1709 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1710 return A->getUniqueID() < B->getUniqueID();
1713 // Emit an arange table for each CU we used.
1714 for (DwarfCompileUnit *CU : CUs) {
1715 std::vector<ArangeSpan> &List = Spans[CU];
1717 // Describe the skeleton CU's offset and length, not the dwo file's.
1718 if (auto *Skel = CU->getSkeleton())
1721 // Emit size of content not including length itself.
1722 unsigned ContentSize =
1723 sizeof(int16_t) + // DWARF ARange version number
1724 sizeof(int32_t) + // Offset of CU in the .debug_info section
1725 sizeof(int8_t) + // Pointer Size (in bytes)
1726 sizeof(int8_t); // Segment Size (in bytes)
1728 unsigned TupleSize = PtrSize * 2;
1730 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1732 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1734 ContentSize += Padding;
1735 ContentSize += (List.size() + 1) * TupleSize;
1737 // For each compile unit, write the list of spans it covers.
1738 Asm->OutStreamer->AddComment("Length of ARange Set");
1739 Asm->EmitInt32(ContentSize);
1740 Asm->OutStreamer->AddComment("DWARF Arange version number");
1741 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1742 Asm->OutStreamer->AddComment("Offset Into Debug Info Section");
1743 Asm->emitSectionOffset(CU->getLabelBegin());
1744 Asm->OutStreamer->AddComment("Address Size (in bytes)");
1745 Asm->EmitInt8(PtrSize);
1746 Asm->OutStreamer->AddComment("Segment Size (in bytes)");
1749 Asm->OutStreamer->EmitFill(Padding, 0xff);
1751 for (const ArangeSpan &Span : List) {
1752 Asm->EmitLabelReference(Span.Start, PtrSize);
1754 // Calculate the size as being from the span start to it's end.
1756 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1758 // For symbols without an end marker (e.g. common), we
1759 // write a single arange entry containing just that one symbol.
1760 uint64_t Size = SymSize[Span.Start];
1764 Asm->OutStreamer->EmitIntValue(Size, PtrSize);
1768 Asm->OutStreamer->AddComment("ARange terminator");
1769 Asm->OutStreamer->EmitIntValue(0, PtrSize);
1770 Asm->OutStreamer->EmitIntValue(0, PtrSize);
1774 // Emit visible names into a debug ranges section.
1775 void DwarfDebug::emitDebugRanges() {
1776 // Start the dwarf ranges section.
1777 Asm->OutStreamer->SwitchSection(
1778 Asm->getObjFileLowering().getDwarfRangesSection());
1780 // Size for our labels.
1781 unsigned char Size = Asm->getDataLayout().getPointerSize();
1783 // Grab the specific ranges for the compile units in the module.
1784 for (const auto &I : CUMap) {
1785 DwarfCompileUnit *TheCU = I.second;
1787 if (auto *Skel = TheCU->getSkeleton())
1790 // Iterate over the misc ranges for the compile units in the module.
1791 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1792 // Emit our symbol so we can find the beginning of the range.
1793 Asm->OutStreamer->EmitLabel(List.getSym());
1795 for (const RangeSpan &Range : List.getRanges()) {
1796 const MCSymbol *Begin = Range.getStart();
1797 const MCSymbol *End = Range.getEnd();
1798 assert(Begin && "Range without a begin symbol?");
1799 assert(End && "Range without an end symbol?");
1800 if (auto *Base = TheCU->getBaseAddress()) {
1801 Asm->EmitLabelDifference(Begin, Base, Size);
1802 Asm->EmitLabelDifference(End, Base, Size);
1804 Asm->OutStreamer->EmitSymbolValue(Begin, Size);
1805 Asm->OutStreamer->EmitSymbolValue(End, Size);
1809 // And terminate the list with two 0 values.
1810 Asm->OutStreamer->EmitIntValue(0, Size);
1811 Asm->OutStreamer->EmitIntValue(0, Size);
1816 // DWARF5 Experimental Separate Dwarf emitters.
1818 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1819 std::unique_ptr<DwarfUnit> NewU) {
1820 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1821 U.getCUNode()->getSplitDebugFilename());
1823 if (!CompilationDir.empty())
1824 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1826 addGnuPubAttributes(*NewU, Die);
1828 SkeletonHolder.addUnit(std::move(NewU));
1831 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1832 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1833 // DW_AT_addr_base, DW_AT_ranges_base.
1834 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1836 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1837 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1838 DwarfCompileUnit &NewCU = *OwnedUnit;
1839 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1841 NewCU.initStmtList();
1843 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1848 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1849 // compile units that would normally be in debug_info.
1850 void DwarfDebug::emitDebugInfoDWO() {
1851 assert(useSplitDwarf() && "No split dwarf debug info?");
1852 // Don't emit relocations into the dwo file.
1853 InfoHolder.emitUnits(/* UseOffsets */ true);
1856 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1857 // abbreviations for the .debug_info.dwo section.
1858 void DwarfDebug::emitDebugAbbrevDWO() {
1859 assert(useSplitDwarf() && "No split dwarf?");
1860 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1863 void DwarfDebug::emitDebugLineDWO() {
1864 assert(useSplitDwarf() && "No split dwarf?");
1865 Asm->OutStreamer->SwitchSection(
1866 Asm->getObjFileLowering().getDwarfLineDWOSection());
1867 SplitTypeUnitFileTable.Emit(*Asm->OutStreamer);
1870 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1871 // string section and is identical in format to traditional .debug_str
1873 void DwarfDebug::emitDebugStrDWO() {
1874 assert(useSplitDwarf() && "No split dwarf?");
1875 MCSection *OffSec = Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1876 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1880 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1881 if (!useSplitDwarf())
1884 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory());
1885 return &SplitTypeUnitFileTable;
1888 static uint64_t makeTypeSignature(StringRef Identifier) {
1890 Hash.update(Identifier);
1891 // ... take the least significant 8 bytes and return those. Our MD5
1892 // implementation always returns its results in little endian, swap bytes
1894 MD5::MD5Result Result;
1896 return support::endian::read64le(Result + 8);
1899 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1900 StringRef Identifier, DIE &RefDie,
1901 const DICompositeType *CTy) {
1902 // Fast path if we're building some type units and one has already used the
1903 // address pool we know we're going to throw away all this work anyway, so
1904 // don't bother building dependent types.
1905 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1908 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1910 CU.addDIETypeSignature(RefDie, *TU);
1914 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1915 AddrPool.resetUsedFlag();
1917 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1918 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1919 this, &InfoHolder, getDwoLineTable(CU));
1920 DwarfTypeUnit &NewTU = *OwnedUnit;
1921 DIE &UnitDie = NewTU.getUnitDie();
1923 TypeUnitsUnderConstruction.push_back(
1924 std::make_pair(std::move(OwnedUnit), CTy));
1926 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1929 uint64_t Signature = makeTypeSignature(Identifier);
1930 NewTU.setTypeSignature(Signature);
1932 if (useSplitDwarf())
1933 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
1935 CU.applyStmtList(UnitDie);
1937 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
1940 NewTU.setType(NewTU.createTypeDIE(CTy));
1943 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
1944 TypeUnitsUnderConstruction.clear();
1946 // Types referencing entries in the address table cannot be placed in type
1948 if (AddrPool.hasBeenUsed()) {
1950 // Remove all the types built while building this type.
1951 // This is pessimistic as some of these types might not be dependent on
1952 // the type that used an address.
1953 for (const auto &TU : TypeUnitsToAdd)
1954 DwarfTypeUnits.erase(TU.second);
1956 // Construct this type in the CU directly.
1957 // This is inefficient because all the dependent types will be rebuilt
1958 // from scratch, including building them in type units, discovering that
1959 // they depend on addresses, throwing them out and rebuilding them.
1960 CU.constructTypeDIE(RefDie, cast<DICompositeType>(CTy));
1964 // If the type wasn't dependent on fission addresses, finish adding the type
1965 // and all its dependent types.
1966 for (auto &TU : TypeUnitsToAdd)
1967 InfoHolder.addUnit(std::move(TU.first));
1969 CU.addDIETypeSignature(RefDie, NewTU);
1972 // Accelerator table mutators - add each name along with its companion
1973 // DIE to the proper table while ensuring that the name that we're going
1974 // to reference is in the string table. We do this since the names we
1975 // add may not only be identical to the names in the DIE.
1976 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
1977 if (!useDwarfAccelTables())
1979 AccelNames.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1982 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
1983 if (!useDwarfAccelTables())
1985 AccelObjC.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1988 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
1989 if (!useDwarfAccelTables())
1991 AccelNamespace.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);
1994 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
1995 if (!useDwarfAccelTables())
1997 AccelTypes.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die);