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(TypedDebugNodeRef<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 MDType *DbgVariable::getType() const {
145 MDType *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 MDType *subType = Ty;
174 uint16_t tag = Ty->getTag();
176 if (tag == dwarf::DW_TAG_pointer_type)
177 subType = resolve(cast<MDDerivedType>(Ty)->getBaseType());
179 auto Elements = cast<MDCompositeTypeBase>(subType)->getElements();
180 for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
181 auto *DT = cast<MDDerivedTypeBase>(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), PrevLabel(nullptr),
196 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(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<MDSubprogram>(Context))
310 if (auto *T = dyn_cast<MDType>(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.
366 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
367 StringRef FN = DIUnit->getFilename();
368 CompilationDir = DIUnit->getDirectory();
370 auto OwnedUnit = make_unique<DwarfCompileUnit>(
371 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
372 DwarfCompileUnit &NewCU = *OwnedUnit;
373 DIE &Die = NewCU.getUnitDie();
374 InfoHolder.addUnit(std::move(OwnedUnit));
376 NewCU.setSkeleton(constructSkeletonCU(NewCU));
378 // LTO with assembly output shares a single line table amongst multiple CUs.
379 // To avoid the compilation directory being ambiguous, let the line table
380 // explicitly describe the directory of all files, never relying on the
381 // compilation directory.
382 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
383 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
384 NewCU.getUniqueID(), CompilationDir);
386 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer());
387 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
388 DIUnit->getSourceLanguage());
389 NewCU.addString(Die, dwarf::DW_AT_name, FN);
391 if (!useSplitDwarf()) {
392 NewCU.initStmtList();
394 // If we're using split dwarf the compilation dir is going to be in the
395 // skeleton CU and so we don't need to duplicate it here.
396 if (!CompilationDir.empty())
397 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
399 addGnuPubAttributes(NewCU, Die);
402 if (DIUnit->isOptimized())
403 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
405 StringRef Flags = DIUnit->getFlags();
407 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
409 if (unsigned RVer = DIUnit->getRuntimeVersion())
410 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
411 dwarf::DW_FORM_data1, RVer);
414 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
416 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
418 CUMap.insert(std::make_pair(DIUnit, &NewCU));
419 CUDieMap.insert(std::make_pair(&Die, &NewCU));
423 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
425 DIImportedEntity Module = cast<MDImportedEntity>(N);
426 if (DIE *D = TheCU.getOrCreateContextDIE(Module->getScope()))
427 D->addChild(TheCU.constructImportedEntityDIE(Module));
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 DICompileUnit CUNode = cast<MDCompileUnit>(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<MDType>(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<MDType>(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<MDSubprogram>(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 DICompileUnit TheCU = cast<MDCompileUnit>(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 TheCU.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.
663 DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV,
664 DIVariable &Cleansed) {
665 // More then one inlined variable corresponds to one abstract variable.
667 auto I = AbstractVariables.find(Cleansed);
668 if (I != AbstractVariables.end())
669 return I->second.get();
673 DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV) {
675 return getExistingAbstractVariable(IV, Cleansed);
678 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
679 LexicalScope *Scope) {
680 auto AbsDbgVariable =
681 make_unique<DbgVariable>(Var, nullptr, DIExpression(), this);
682 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
683 AbstractVariables[Var] = std::move(AbsDbgVariable);
686 void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV,
687 const MDNode *ScopeNode) {
689 if (getExistingAbstractVariable(IV, Cleansed))
692 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(
693 cast<MDLocalScope>(ScopeNode)));
696 void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(
697 InlinedVariable IV, const MDNode *ScopeNode) {
699 if (getExistingAbstractVariable(IV, Cleansed))
702 if (LexicalScope *Scope =
703 LScopes.findAbstractScope(cast_or_null<MDLocalScope>(ScopeNode)))
704 createAbstractVariable(Cleansed, Scope);
707 // Collect variable information from side table maintained by MMI.
708 void DwarfDebug::collectVariableInfoFromMMITable(
709 DenseSet<InlinedVariable> &Processed) {
710 for (const auto &VI : MMI->getVariableDbgInfo()) {
713 assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
714 "Expected inlined-at fields to agree");
716 InlinedVariable Var(VI.Var, VI.Loc->getInlinedAt());
717 Processed.insert(Var);
718 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
720 // If variable scope is not found then skip this variable.
724 DIExpression Expr = cast_or_null<MDExpression>(VI.Expr);
725 ensureAbstractVariableIsCreatedIfScoped(Var, Scope->getScopeNode());
727 make_unique<DbgVariable>(Var.first, Var.second, Expr, this, VI.Slot);
728 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
729 ConcreteVariables.push_back(std::move(RegVar));
733 // Get .debug_loc entry for the instruction range starting at MI.
734 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
735 const MDExpression *Expr = MI->getDebugExpression();
737 assert(MI->getNumOperands() == 4);
738 if (MI->getOperand(0).isReg()) {
739 MachineLocation MLoc;
740 // If the second operand is an immediate, this is a
741 // register-indirect address.
742 if (!MI->getOperand(1).isImm())
743 MLoc.set(MI->getOperand(0).getReg());
745 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
746 return DebugLocEntry::Value(Expr, MLoc);
748 if (MI->getOperand(0).isImm())
749 return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm());
750 if (MI->getOperand(0).isFPImm())
751 return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm());
752 if (MI->getOperand(0).isCImm())
753 return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm());
755 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
758 /// Determine whether two variable pieces overlap.
759 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
760 if (!P1->isBitPiece() || !P2->isBitPiece())
762 unsigned l1 = P1->getBitPieceOffset();
763 unsigned l2 = P2->getBitPieceOffset();
764 unsigned r1 = l1 + P1->getBitPieceSize();
765 unsigned r2 = l2 + P2->getBitPieceSize();
766 // True where [l1,r1[ and [r1,r2[ overlap.
767 return (l1 < r2) && (l2 < r1);
770 /// Build the location list for all DBG_VALUEs in the function that
771 /// describe the same variable. If the ranges of several independent
772 /// pieces of the same variable overlap partially, split them up and
773 /// combine the ranges. The resulting DebugLocEntries are will have
774 /// strict monotonically increasing begin addresses and will never
779 // Ranges History [var, loc, piece ofs size]
780 // 0 | [x, (reg0, piece 0, 32)]
781 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
783 // 3 | [clobber reg0]
784 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
789 // [0-1] [x, (reg0, piece 0, 32)]
790 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
791 // [3-4] [x, (reg1, piece 32, 32)]
792 // [4- ] [x, (mem, piece 0, 64)]
794 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
795 const DbgValueHistoryMap::InstrRanges &Ranges) {
796 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
798 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
799 const MachineInstr *Begin = I->first;
800 const MachineInstr *End = I->second;
801 assert(Begin->isDebugValue() && "Invalid History entry");
803 // Check if a variable is inaccessible in this range.
804 if (Begin->getNumOperands() > 1 &&
805 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
810 // If this piece overlaps with any open ranges, truncate them.
811 DIExpression DIExpr = Begin->getDebugExpression();
812 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
813 [&](DebugLocEntry::Value R) {
814 return piecesOverlap(DIExpr, R.getExpression());
816 OpenRanges.erase(Last, OpenRanges.end());
818 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
819 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
821 const MCSymbol *EndLabel;
823 EndLabel = getLabelAfterInsn(End);
824 else if (std::next(I) == Ranges.end())
825 EndLabel = Asm->getFunctionEnd();
827 EndLabel = getLabelBeforeInsn(std::next(I)->first);
828 assert(EndLabel && "Forgot label after instruction ending a range!");
830 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
832 auto Value = getDebugLocValue(Begin);
833 DebugLocEntry Loc(StartLabel, EndLabel, Value);
834 bool couldMerge = false;
836 // If this is a piece, it may belong to the current DebugLocEntry.
837 if (DIExpr->isBitPiece()) {
838 // Add this value to the list of open ranges.
839 OpenRanges.push_back(Value);
841 // Attempt to add the piece to the last entry.
842 if (!DebugLoc.empty())
843 if (DebugLoc.back().MergeValues(Loc))
848 // Need to add a new DebugLocEntry. Add all values from still
849 // valid non-overlapping pieces.
850 if (OpenRanges.size())
851 Loc.addValues(OpenRanges);
853 DebugLoc.push_back(std::move(Loc));
856 // Attempt to coalesce the ranges of two otherwise identical
858 auto CurEntry = DebugLoc.rbegin();
859 auto PrevEntry = std::next(CurEntry);
860 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
864 dbgs() << CurEntry->getValues().size() << " Values:\n";
865 for (auto Value : CurEntry->getValues()) {
866 Value.getExpression()->dump();
874 // Find variables for each lexical scope.
875 void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
876 DenseSet<InlinedVariable> &Processed) {
877 // Grab the variable info that was squirreled away in the MMI side-table.
878 collectVariableInfoFromMMITable(Processed);
880 for (const auto &I : DbgValues) {
881 InlinedVariable IV = I.first;
882 if (Processed.count(IV))
885 // Instruction ranges, specifying where IV is accessible.
886 const auto &Ranges = I.second;
890 LexicalScope *Scope = nullptr;
891 if (const MDLocation *IA = IV.second)
892 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA);
894 Scope = LScopes.findLexicalScope(IV.first->getScope());
895 // If variable scope is not found then skip this variable.
899 Processed.insert(IV);
900 const MachineInstr *MInsn = Ranges.front().first;
901 assert(MInsn->isDebugValue() && "History must begin with debug value");
902 ensureAbstractVariableIsCreatedIfScoped(IV, Scope->getScopeNode());
903 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
904 DbgVariable *RegVar = ConcreteVariables.back().get();
905 InfoHolder.addScopeVariable(Scope, RegVar);
907 // Check if the first DBG_VALUE is valid for the rest of the function.
908 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
911 // Handle multiple DBG_VALUE instructions describing one variable.
912 RegVar->setDebugLocListIndex(
913 DebugLocs.startList(&TheCU, Asm->createTempSymbol("debug_loc")));
915 // Build the location list for this variable.
916 SmallVector<DebugLocEntry, 8> Entries;
917 buildLocationList(Entries, Ranges);
919 // If the variable has an MDBasicType, extract it. Basic types cannot have
920 // unique identifiers, so don't bother resolving the type with the
922 const MDBasicType *BT = dyn_cast<MDBasicType>(
923 static_cast<const Metadata *>(IV.first->getType()));
925 // Finalize the entry by lowering it into a DWARF bytestream.
926 for (auto &Entry : Entries)
927 Entry.finalize(*Asm, DebugLocs, BT);
930 // Collect info for variables that were optimized out.
931 for (DIVariable DV : SP->getVariables()) {
932 if (!Processed.insert(InlinedVariable(DV, nullptr)).second)
934 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) {
935 ensureAbstractVariableIsCreatedIfScoped(InlinedVariable(DV, nullptr),
936 Scope->getScopeNode());
938 ConcreteVariables.push_back(
939 make_unique<DbgVariable>(DV, nullptr, NoExpr, 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 DIVariable 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 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 (MDLocation *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 DISubprogram SP = cast<MDSubprogram>(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 DISubprogram SP = cast<MDSubprogram>(AScope->getScopeNode());
1219 // Collect info for variables that were optimized out.
1220 for (DIVariable 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<MDScope>(S)) {
1257 Fn = Scope->getFilename();
1258 Dir = Scope->getDirectory();
1259 if (auto *LBF = dyn_cast<MDLexicalBlockFile>(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, const 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 const MCSection *PSec =
1382 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1383 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1385 emitDebugPubSection(GnuStyle, PSec, "Names",
1386 &DwarfCompileUnit::getGlobalNames);
1389 void DwarfDebug::emitDebugPubSection(
1390 bool GnuStyle, const 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 const MCSection *PSec =
1451 GnuStyle ? 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 MDBasicType *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 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 MDBasicType *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 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) {
1547 Asm->OutStreamer.AddComment("Loc expr size");
1548 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1549 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1550 Asm->EmitLabelDifference(end, begin, 2);
1551 Asm->OutStreamer.EmitLabel(begin);
1553 APByteStreamer Streamer(*Asm);
1554 emitDebugLocEntry(Streamer, Entry);
1556 Asm->OutStreamer.EmitLabel(end);
1559 // Emit locations into the debug loc section.
1560 void DwarfDebug::emitDebugLoc() {
1561 // Start the dwarf loc section.
1562 Asm->OutStreamer.SwitchSection(
1563 Asm->getObjFileLowering().getDwarfLocSection());
1564 unsigned char Size = Asm->getDataLayout().getPointerSize();
1565 for (const auto &List : DebugLocs.getLists()) {
1566 Asm->OutStreamer.EmitLabel(List.Label);
1567 const DwarfCompileUnit *CU = List.CU;
1568 for (const auto &Entry : DebugLocs.getEntries(List)) {
1569 // Set up the range. This range is relative to the entry point of the
1570 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1571 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1572 if (auto *Base = CU->getBaseAddress()) {
1573 Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
1574 Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
1576 Asm->OutStreamer.EmitSymbolValue(Entry.BeginSym, Size);
1577 Asm->OutStreamer.EmitSymbolValue(Entry.EndSym, Size);
1580 emitDebugLocEntryLocation(Entry);
1582 Asm->OutStreamer.EmitIntValue(0, Size);
1583 Asm->OutStreamer.EmitIntValue(0, Size);
1587 void DwarfDebug::emitDebugLocDWO() {
1588 Asm->OutStreamer.SwitchSection(
1589 Asm->getObjFileLowering().getDwarfLocDWOSection());
1590 for (const auto &List : DebugLocs.getLists()) {
1591 Asm->OutStreamer.EmitLabel(List.Label);
1592 for (const auto &Entry : DebugLocs.getEntries(List)) {
1593 // Just always use start_length for now - at least that's one address
1594 // rather than two. We could get fancier and try to, say, reuse an
1595 // address we know we've emitted elsewhere (the start of the function?
1596 // The start of the CU or CU subrange that encloses this range?)
1597 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1598 unsigned idx = AddrPool.getIndex(Entry.BeginSym);
1599 Asm->EmitULEB128(idx);
1600 Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4);
1602 emitDebugLocEntryLocation(Entry);
1604 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1609 const MCSymbol *Start, *End;
1612 // Emit a debug aranges section, containing a CU lookup for any
1613 // address we can tie back to a CU.
1614 void DwarfDebug::emitDebugARanges() {
1615 // Provides a unique id per text section.
1616 MapVector<const MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1618 // Filter labels by section.
1619 for (const SymbolCU &SCU : ArangeLabels) {
1620 if (SCU.Sym->isInSection()) {
1621 // Make a note of this symbol and it's section.
1622 const MCSection *Section = &SCU.Sym->getSection();
1623 if (!Section->getKind().isMetadata())
1624 SectionMap[Section].push_back(SCU);
1626 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1627 // appear in the output. This sucks as we rely on sections to build
1628 // arange spans. We can do it without, but it's icky.
1629 SectionMap[nullptr].push_back(SCU);
1633 // Add terminating symbols for each section.
1634 for (const auto &I : SectionMap) {
1635 const MCSection *Section = I.first;
1636 MCSymbol *Sym = nullptr;
1639 Sym = Asm->OutStreamer.endSection(Section);
1641 // Insert a final terminator.
1642 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1645 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1647 for (auto &I : SectionMap) {
1648 const MCSection *Section = I.first;
1649 SmallVector<SymbolCU, 8> &List = I.second;
1650 if (List.size() < 2)
1653 // If we have no section (e.g. common), just write out
1654 // individual spans for each symbol.
1656 for (const SymbolCU &Cur : List) {
1658 Span.Start = Cur.Sym;
1661 Spans[Cur.CU].push_back(Span);
1666 // Sort the symbols by offset within the section.
1667 std::sort(List.begin(), List.end(),
1668 [&](const SymbolCU &A, const SymbolCU &B) {
1669 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1670 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1672 // Symbols with no order assigned should be placed at the end.
1673 // (e.g. section end labels)
1681 // Build spans between each label.
1682 const MCSymbol *StartSym = List[0].Sym;
1683 for (size_t n = 1, e = List.size(); n < e; n++) {
1684 const SymbolCU &Prev = List[n - 1];
1685 const SymbolCU &Cur = List[n];
1687 // Try and build the longest span we can within the same CU.
1688 if (Cur.CU != Prev.CU) {
1690 Span.Start = StartSym;
1692 Spans[Prev.CU].push_back(Span);
1698 // Start the dwarf aranges section.
1699 Asm->OutStreamer.SwitchSection(
1700 Asm->getObjFileLowering().getDwarfARangesSection());
1702 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1704 // Build a list of CUs used.
1705 std::vector<DwarfCompileUnit *> CUs;
1706 for (const auto &it : Spans) {
1707 DwarfCompileUnit *CU = it.first;
1711 // Sort the CU list (again, to ensure consistent output order).
1712 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1713 return A->getUniqueID() < B->getUniqueID();
1716 // Emit an arange table for each CU we used.
1717 for (DwarfCompileUnit *CU : CUs) {
1718 std::vector<ArangeSpan> &List = Spans[CU];
1720 // Describe the skeleton CU's offset and length, not the dwo file's.
1721 if (auto *Skel = CU->getSkeleton())
1724 // Emit size of content not including length itself.
1725 unsigned ContentSize =
1726 sizeof(int16_t) + // DWARF ARange version number
1727 sizeof(int32_t) + // Offset of CU in the .debug_info section
1728 sizeof(int8_t) + // Pointer Size (in bytes)
1729 sizeof(int8_t); // Segment Size (in bytes)
1731 unsigned TupleSize = PtrSize * 2;
1733 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1735 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1737 ContentSize += Padding;
1738 ContentSize += (List.size() + 1) * TupleSize;
1740 // For each compile unit, write the list of spans it covers.
1741 Asm->OutStreamer.AddComment("Length of ARange Set");
1742 Asm->EmitInt32(ContentSize);
1743 Asm->OutStreamer.AddComment("DWARF Arange version number");
1744 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1745 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1746 Asm->emitSectionOffset(CU->getLabelBegin());
1747 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1748 Asm->EmitInt8(PtrSize);
1749 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1752 Asm->OutStreamer.EmitFill(Padding, 0xff);
1754 for (const ArangeSpan &Span : List) {
1755 Asm->EmitLabelReference(Span.Start, PtrSize);
1757 // Calculate the size as being from the span start to it's end.
1759 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1761 // For symbols without an end marker (e.g. common), we
1762 // write a single arange entry containing just that one symbol.
1763 uint64_t Size = SymSize[Span.Start];
1767 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1771 Asm->OutStreamer.AddComment("ARange terminator");
1772 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1773 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1777 // Emit visible names into a debug ranges section.
1778 void DwarfDebug::emitDebugRanges() {
1779 // Start the dwarf ranges section.
1780 Asm->OutStreamer.SwitchSection(
1781 Asm->getObjFileLowering().getDwarfRangesSection());
1783 // Size for our labels.
1784 unsigned char Size = Asm->getDataLayout().getPointerSize();
1786 // Grab the specific ranges for the compile units in the module.
1787 for (const auto &I : CUMap) {
1788 DwarfCompileUnit *TheCU = I.second;
1790 if (auto *Skel = TheCU->getSkeleton())
1793 // Iterate over the misc ranges for the compile units in the module.
1794 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1795 // Emit our symbol so we can find the beginning of the range.
1796 Asm->OutStreamer.EmitLabel(List.getSym());
1798 for (const RangeSpan &Range : List.getRanges()) {
1799 const MCSymbol *Begin = Range.getStart();
1800 const MCSymbol *End = Range.getEnd();
1801 assert(Begin && "Range without a begin symbol?");
1802 assert(End && "Range without an end symbol?");
1803 if (auto *Base = TheCU->getBaseAddress()) {
1804 Asm->EmitLabelDifference(Begin, Base, Size);
1805 Asm->EmitLabelDifference(End, Base, Size);
1807 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1808 Asm->OutStreamer.EmitSymbolValue(End, Size);
1812 // And terminate the list with two 0 values.
1813 Asm->OutStreamer.EmitIntValue(0, Size);
1814 Asm->OutStreamer.EmitIntValue(0, Size);
1819 // DWARF5 Experimental Separate Dwarf emitters.
1821 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1822 std::unique_ptr<DwarfUnit> NewU) {
1823 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1824 U.getCUNode()->getSplitDebugFilename());
1826 if (!CompilationDir.empty())
1827 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1829 addGnuPubAttributes(*NewU, Die);
1831 SkeletonHolder.addUnit(std::move(NewU));
1834 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1835 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1836 // DW_AT_addr_base, DW_AT_ranges_base.
1837 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1839 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1840 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1841 DwarfCompileUnit &NewCU = *OwnedUnit;
1842 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1844 NewCU.initStmtList();
1846 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1851 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1852 // compile units that would normally be in debug_info.
1853 void DwarfDebug::emitDebugInfoDWO() {
1854 assert(useSplitDwarf() && "No split dwarf debug info?");
1855 // Don't emit relocations into the dwo file.
1856 InfoHolder.emitUnits(/* UseOffsets */ true);
1859 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1860 // abbreviations for the .debug_info.dwo section.
1861 void DwarfDebug::emitDebugAbbrevDWO() {
1862 assert(useSplitDwarf() && "No split dwarf?");
1863 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1866 void DwarfDebug::emitDebugLineDWO() {
1867 assert(useSplitDwarf() && "No split dwarf?");
1868 Asm->OutStreamer.SwitchSection(
1869 Asm->getObjFileLowering().getDwarfLineDWOSection());
1870 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
1873 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1874 // string section and is identical in format to traditional .debug_str
1876 void DwarfDebug::emitDebugStrDWO() {
1877 assert(useSplitDwarf() && "No split dwarf?");
1878 const MCSection *OffSec =
1879 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1880 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1884 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1885 if (!useSplitDwarf())
1888 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory());
1889 return &SplitTypeUnitFileTable;
1892 static uint64_t makeTypeSignature(StringRef Identifier) {
1894 Hash.update(Identifier);
1895 // ... take the least significant 8 bytes and return those. Our MD5
1896 // implementation always returns its results in little endian, swap bytes
1898 MD5::MD5Result Result;
1900 return support::endian::read64le(Result + 8);
1903 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1904 StringRef Identifier, DIE &RefDie,
1905 DICompositeType CTy) {
1906 // Fast path if we're building some type units and one has already used the
1907 // address pool we know we're going to throw away all this work anyway, so
1908 // don't bother building dependent types.
1909 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1912 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1914 CU.addDIETypeSignature(RefDie, *TU);
1918 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1919 AddrPool.resetUsedFlag();
1921 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1922 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1923 this, &InfoHolder, getDwoLineTable(CU));
1924 DwarfTypeUnit &NewTU = *OwnedUnit;
1925 DIE &UnitDie = NewTU.getUnitDie();
1927 TypeUnitsUnderConstruction.push_back(
1928 std::make_pair(std::move(OwnedUnit), CTy));
1930 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1933 uint64_t Signature = makeTypeSignature(Identifier);
1934 NewTU.setTypeSignature(Signature);
1936 if (useSplitDwarf())
1937 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
1939 CU.applyStmtList(UnitDie);
1941 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
1944 NewTU.setType(NewTU.createTypeDIE(CTy));
1947 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
1948 TypeUnitsUnderConstruction.clear();
1950 // Types referencing entries in the address table cannot be placed in type
1952 if (AddrPool.hasBeenUsed()) {
1954 // Remove all the types built while building this type.
1955 // This is pessimistic as some of these types might not be dependent on
1956 // the type that used an address.
1957 for (const auto &TU : TypeUnitsToAdd)
1958 DwarfTypeUnits.erase(TU.second);
1960 // Construct this type in the CU directly.
1961 // This is inefficient because all the dependent types will be rebuilt
1962 // from scratch, including building them in type units, discovering that
1963 // they depend on addresses, throwing them out and rebuilding them.
1964 CU.constructTypeDIE(RefDie, cast<MDCompositeType>(CTy));
1968 // If the type wasn't dependent on fission addresses, finish adding the type
1969 // and all its dependent types.
1970 for (auto &TU : TypeUnitsToAdd)
1971 InfoHolder.addUnit(std::move(TU.first));
1973 CU.addDIETypeSignature(RefDie, NewTU);
1976 // Accelerator table mutators - add each name along with its companion
1977 // DIE to the proper table while ensuring that the name that we're going
1978 // to reference is in the string table. We do this since the names we
1979 // add may not only be identical to the names in the DIE.
1980 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
1981 if (!useDwarfAccelTables())
1983 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1987 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
1988 if (!useDwarfAccelTables())
1990 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1994 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
1995 if (!useDwarfAccelTables())
1997 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2001 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2002 if (!useDwarfAccelTables())
2004 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),