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 "DwarfCompileUnit.h"
18 #include "DwarfExpression.h"
19 #include "DwarfUnit.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/CodeGen/DIE.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include "llvm/Target/TargetFrameLowering.h"
50 #include "llvm/Target/TargetLoweringObjectFile.h"
51 #include "llvm/Target/TargetMachine.h"
52 #include "llvm/Target/TargetOptions.h"
53 #include "llvm/Target/TargetRegisterInfo.h"
54 #include "llvm/Target/TargetSubtargetInfo.h"
57 #define DEBUG_TYPE "dwarfdebug"
60 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
61 cl::desc("Disable debug info printing"));
63 static cl::opt<bool> UnknownLocations(
64 "use-unknown-locations", cl::Hidden,
65 cl::desc("Make an absence of debug location information explicit."),
69 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
70 cl::desc("Generate GNU-style pubnames and pubtypes"),
73 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
75 cl::desc("Generate dwarf aranges"),
79 enum DefaultOnOff { Default, Enable, Disable };
82 static cl::opt<DefaultOnOff>
83 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
84 cl::desc("Output prototype dwarf accelerator tables."),
85 cl::values(clEnumVal(Default, "Default for platform"),
86 clEnumVal(Enable, "Enabled"),
87 clEnumVal(Disable, "Disabled"), clEnumValEnd),
90 static cl::opt<DefaultOnOff>
91 SplitDwarf("split-dwarf", cl::Hidden,
92 cl::desc("Output DWARF5 split debug info."),
93 cl::values(clEnumVal(Default, "Default for platform"),
94 clEnumVal(Enable, "Enabled"),
95 clEnumVal(Disable, "Disabled"), clEnumValEnd),
98 static cl::opt<DefaultOnOff>
99 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
100 cl::desc("Generate DWARF pubnames and pubtypes sections"),
101 cl::values(clEnumVal(Default, "Default for platform"),
102 clEnumVal(Enable, "Enabled"),
103 clEnumVal(Disable, "Disabled"), clEnumValEnd),
106 static const char *const DWARFGroupName = "DWARF Emission";
107 static const char *const DbgTimerName = "DWARF Debug Writer";
109 void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) {
111 Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op)
112 : dwarf::OperationEncodingString(Op));
115 void DebugLocDwarfExpression::EmitSigned(int64_t Value) {
116 BS.EmitSLEB128(Value, Twine(Value));
119 void DebugLocDwarfExpression::EmitUnsigned(uint64_t Value) {
120 BS.EmitULEB128(Value, Twine(Value));
123 bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) {
124 // This information is not available while emitting .debug_loc entries.
128 //===----------------------------------------------------------------------===//
130 /// resolve - Look in the DwarfDebug map for the MDNode that
131 /// corresponds to the reference.
132 template <typename T> T *DbgVariable::resolve(TypedDebugNodeRef<T> Ref) const {
133 return DD->resolve(Ref);
136 bool DbgVariable::isBlockByrefVariable() const {
137 assert(Var && "Invalid complex DbgVariable!");
138 return Var->getType()
139 .resolve(DD->getTypeIdentifierMap())
140 ->isBlockByrefStruct();
143 DIType DbgVariable::getType() const {
144 MDType *Ty = Var->getType().resolve(DD->getTypeIdentifierMap());
145 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
146 // addresses instead.
147 if (Ty->isBlockByrefStruct()) {
148 /* Byref variables, in Blocks, are declared by the programmer as
149 "SomeType VarName;", but the compiler creates a
150 __Block_byref_x_VarName struct, and gives the variable VarName
151 either the struct, or a pointer to the struct, as its type. This
152 is necessary for various behind-the-scenes things the compiler
153 needs to do with by-reference variables in blocks.
155 However, as far as the original *programmer* is concerned, the
156 variable should still have type 'SomeType', as originally declared.
158 The following function dives into the __Block_byref_x_VarName
159 struct to find the original type of the variable. This will be
160 passed back to the code generating the type for the Debug
161 Information Entry for the variable 'VarName'. 'VarName' will then
162 have the original type 'SomeType' in its debug information.
164 The original type 'SomeType' will be the type of the field named
165 'VarName' inside the __Block_byref_x_VarName struct.
167 NOTE: In order for this to not completely fail on the debugger
168 side, the Debug Information Entry for the variable VarName needs to
169 have a DW_AT_location that tells the debugger how to unwind through
170 the pointers and __Block_byref_x_VarName struct to find the actual
171 value of the variable. The function addBlockByrefType does this. */
172 MDType *subType = Ty;
173 uint16_t tag = Ty->getTag();
175 if (tag == dwarf::DW_TAG_pointer_type)
176 subType = resolve(DITypeRef(cast<MDDerivedType>(Ty)->getBaseType()));
178 auto Elements = cast<MDCompositeTypeBase>(subType)->getElements();
179 for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
180 auto *DT = cast<MDDerivedTypeBase>(Elements[i]);
181 if (getName() == DT->getName())
182 return resolve(DITypeRef(DT->getBaseType()));
188 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
189 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
190 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
191 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
193 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
194 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr),
195 InfoHolder(A, "info_string", DIEValueAllocator),
196 UsedNonDefaultText(false),
197 SkeletonHolder(A, "skel_string", DIEValueAllocator),
198 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
199 IsPS4(Triple(A->getTargetTriple()).isPS4()),
200 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
201 dwarf::DW_FORM_data4)),
202 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
203 dwarf::DW_FORM_data4)),
204 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
205 dwarf::DW_FORM_data4)),
206 AccelTypes(TypeAtoms) {
211 // Turn on accelerator tables for Darwin by default, pubnames by
212 // default for non-Darwin/PS4, and handle split dwarf.
213 if (DwarfAccelTables == Default)
214 HasDwarfAccelTables = IsDarwin;
216 HasDwarfAccelTables = DwarfAccelTables == Enable;
218 if (SplitDwarf == Default)
219 HasSplitDwarf = false;
221 HasSplitDwarf = SplitDwarf == Enable;
223 if (DwarfPubSections == Default)
224 HasDwarfPubSections = !IsDarwin && !IsPS4;
226 HasDwarfPubSections = DwarfPubSections == Enable;
228 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
229 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
230 : MMI->getModule()->getDwarfVersion();
232 // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3).
233 // Everybody else uses GNU's.
234 UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3;
236 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
239 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
244 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
245 DwarfDebug::~DwarfDebug() { }
247 static bool isObjCClass(StringRef Name) {
248 return Name.startswith("+") || Name.startswith("-");
251 static bool hasObjCCategory(StringRef Name) {
252 if (!isObjCClass(Name))
255 return Name.find(") ") != StringRef::npos;
258 static void getObjCClassCategory(StringRef In, StringRef &Class,
259 StringRef &Category) {
260 if (!hasObjCCategory(In)) {
261 Class = In.slice(In.find('[') + 1, In.find(' '));
266 Class = In.slice(In.find('[') + 1, In.find('('));
267 Category = In.slice(In.find('[') + 1, In.find(' '));
271 static StringRef getObjCMethodName(StringRef In) {
272 return In.slice(In.find(' ') + 1, In.find(']'));
275 // Add the various names to the Dwarf accelerator table names.
276 // TODO: Determine whether or not we should add names for programs
277 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
278 // is only slightly different than the lookup of non-standard ObjC names.
279 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
280 if (!SP->isDefinition())
282 addAccelName(SP->getName(), Die);
284 // If the linkage name is different than the name, go ahead and output
285 // that as well into the name table.
286 if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName())
287 addAccelName(SP->getLinkageName(), Die);
289 // If this is an Objective-C selector name add it to the ObjC accelerator
291 if (isObjCClass(SP->getName())) {
292 StringRef Class, Category;
293 getObjCClassCategory(SP->getName(), Class, Category);
294 addAccelObjC(Class, Die);
296 addAccelObjC(Category, Die);
297 // Also add the base method name to the name table.
298 addAccelName(getObjCMethodName(SP->getName()), Die);
302 /// isSubprogramContext - Return true if Context is either a subprogram
303 /// or another context nested inside a subprogram.
304 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
307 if (isa<MDSubprogram>(Context))
309 if (auto *T = dyn_cast<MDType>(Context))
310 return isSubprogramContext(resolve(T->getScope()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
335 if (auto *SkelCU = CU.getSkeleton())
339 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
340 assert(Scope && Scope->getScopeNode());
341 assert(Scope->isAbstractScope());
342 assert(!Scope->getInlinedAt());
344 const MDNode *SP = Scope->getScopeNode();
346 ProcessedSPNodes.insert(SP);
348 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
349 // was inlined from another compile unit.
350 auto &CU = SPMap[SP];
351 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
352 CU.constructAbstractSubprogramScopeDIE(Scope);
356 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
357 if (!GenerateGnuPubSections)
360 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
363 // Create new DwarfCompileUnit for the given metadata node with tag
364 // DW_TAG_compile_unit.
365 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
366 StringRef FN = DIUnit->getFilename();
367 CompilationDir = DIUnit->getDirectory();
369 auto OwnedUnit = make_unique<DwarfCompileUnit>(
370 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
371 DwarfCompileUnit &NewCU = *OwnedUnit;
372 DIE &Die = NewCU.getUnitDie();
373 InfoHolder.addUnit(std::move(OwnedUnit));
375 NewCU.setSkeleton(constructSkeletonCU(NewCU));
377 // LTO with assembly output shares a single line table amongst multiple CUs.
378 // To avoid the compilation directory being ambiguous, let the line table
379 // explicitly describe the directory of all files, never relying on the
380 // compilation directory.
381 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
382 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
383 NewCU.getUniqueID(), CompilationDir);
385 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer());
386 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
387 DIUnit->getSourceLanguage());
388 NewCU.addString(Die, dwarf::DW_AT_name, FN);
390 if (!useSplitDwarf()) {
391 NewCU.initStmtList();
393 // If we're using split dwarf the compilation dir is going to be in the
394 // skeleton CU and so we don't need to duplicate it here.
395 if (!CompilationDir.empty())
396 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
398 addGnuPubAttributes(NewCU, Die);
401 if (DIUnit->isOptimized())
402 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
404 StringRef Flags = DIUnit->getFlags();
406 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
408 if (unsigned RVer = DIUnit->getRuntimeVersion())
409 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
410 dwarf::DW_FORM_data1, RVer);
413 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
417 CUMap.insert(std::make_pair(DIUnit, &NewCU));
418 CUDieMap.insert(std::make_pair(&Die, &NewCU));
422 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
424 DIImportedEntity Module = cast<MDImportedEntity>(N);
425 if (DIE *D = TheCU.getOrCreateContextDIE(Module->getScope()))
426 D->addChild(TheCU.constructImportedEntityDIE(Module));
429 // Emit all Dwarf sections that should come prior to the content. Create
430 // global DIEs and emit initial debug info sections. This is invoked by
431 // the target AsmPrinter.
432 void DwarfDebug::beginModule() {
433 if (DisableDebugInfoPrinting)
436 const Module *M = MMI->getModule();
438 FunctionDIs = makeSubprogramMap(*M);
440 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
443 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
445 SingleCU = CU_Nodes->getNumOperands() == 1;
447 for (MDNode *N : CU_Nodes->operands()) {
448 DICompileUnit CUNode = cast<MDCompileUnit>(N);
449 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
450 for (auto *IE : CUNode->getImportedEntities())
451 ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE));
452 // Stable sort to preserve the order of appearance of imported entities.
453 // This is to avoid out-of-order processing of interdependent declarations
454 // within the same scope, e.g. { namespace A = base; namespace B = A; }
455 std::stable_sort(ScopesWithImportedEntities.begin(),
456 ScopesWithImportedEntities.end(), less_first());
457 for (auto *GV : CUNode->getGlobalVariables())
458 CU.getOrCreateGlobalVariableDIE(GV);
459 for (auto *SP : CUNode->getSubprograms())
460 SPMap.insert(std::make_pair(SP, &CU));
461 for (DIType Ty : CUNode->getEnumTypes()) {
462 // The enum types array by design contains pointers to
463 // MDNodes rather than DIRefs. Unique them here.
464 DIType UniqueTy = cast<MDType>(resolve(Ty->getRef()));
465 CU.getOrCreateTypeDIE(UniqueTy);
467 for (DIType Ty : CUNode->getRetainedTypes()) {
468 // The retained types array by design contains pointers to
469 // MDNodes rather than DIRefs. Unique them here.
470 DIType UniqueTy = cast<MDType>(resolve(Ty->getRef()));
471 CU.getOrCreateTypeDIE(UniqueTy);
473 // Emit imported_modules last so that the relevant context is already
475 for (auto *IE : CUNode->getImportedEntities())
476 constructAndAddImportedEntityDIE(CU, IE);
479 // Tell MMI that we have debug info.
480 MMI->setDebugInfoAvailability(true);
483 void DwarfDebug::finishVariableDefinitions() {
484 for (const auto &Var : ConcreteVariables) {
485 DIE *VariableDie = Var->getDIE();
487 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
488 // in the ConcreteVariables list, rather than looking it up again here.
489 // DIE::getUnit isn't simple - it walks parent pointers, etc.
490 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
492 DbgVariable *AbsVar = getExistingAbstractVariable(
493 InlinedVariable(Var->getVariable(), Var->getInlinedAt()));
494 if (AbsVar && AbsVar->getDIE()) {
495 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
498 Unit->applyVariableAttributes(*Var, *VariableDie);
502 void DwarfDebug::finishSubprogramDefinitions() {
503 for (const auto &P : SPMap)
504 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
505 CU.finishSubprogramDefinition(cast<MDSubprogram>(P.first));
510 // Collect info for variables that were optimized out.
511 void DwarfDebug::collectDeadVariables() {
512 const Module *M = MMI->getModule();
514 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
515 for (MDNode *N : CU_Nodes->operands()) {
516 DICompileUnit TheCU = cast<MDCompileUnit>(N);
517 // Construct subprogram DIE and add variables DIEs.
518 DwarfCompileUnit *SPCU =
519 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
520 assert(SPCU && "Unable to find Compile Unit!");
521 for (auto *SP : TheCU->getSubprograms()) {
522 if (ProcessedSPNodes.count(SP) != 0)
524 SPCU->collectDeadVariables(SP);
530 void DwarfDebug::finalizeModuleInfo() {
531 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
533 finishSubprogramDefinitions();
535 finishVariableDefinitions();
537 // Collect info for variables that were optimized out.
538 collectDeadVariables();
540 // Handle anything that needs to be done on a per-unit basis after
541 // all other generation.
542 for (const auto &P : CUMap) {
543 auto &TheCU = *P.second;
544 // Emit DW_AT_containing_type attribute to connect types with their
545 // vtable holding type.
546 TheCU.constructContainingTypeDIEs();
548 // Add CU specific attributes if we need to add any.
549 // If we're splitting the dwarf out now that we've got the entire
550 // CU then add the dwo id to it.
551 auto *SkCU = TheCU.getSkeleton();
552 if (useSplitDwarf()) {
553 // Emit a unique identifier for this CU.
554 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
555 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
556 dwarf::DW_FORM_data8, ID);
557 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
558 dwarf::DW_FORM_data8, ID);
560 // We don't keep track of which addresses are used in which CU so this
561 // is a bit pessimistic under LTO.
562 if (!AddrPool.isEmpty()) {
563 const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol();
564 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
567 if (!SkCU->getRangeLists().empty()) {
568 const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol();
569 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
574 // If we have code split among multiple sections or non-contiguous
575 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
576 // remain in the .o file, otherwise add a DW_AT_low_pc.
577 // FIXME: We should use ranges allow reordering of code ala
578 // .subsections_via_symbols in mach-o. This would mean turning on
579 // ranges for all subprogram DIEs for mach-o.
580 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
581 if (unsigned NumRanges = TheCU.getRanges().size()) {
583 // A DW_AT_low_pc attribute may also be specified in combination with
584 // DW_AT_ranges to specify the default base address for use in
585 // location lists (see Section 2.6.2) and range lists (see Section
587 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
589 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
590 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
594 // Compute DIE offsets and sizes.
595 InfoHolder.computeSizeAndOffsets();
597 SkeletonHolder.computeSizeAndOffsets();
600 // Emit all Dwarf sections that should come after the content.
601 void DwarfDebug::endModule() {
602 assert(CurFn == nullptr);
603 assert(CurMI == nullptr);
605 // If we aren't actually generating debug info (check beginModule -
606 // conditionalized on !DisableDebugInfoPrinting and the presence of the
607 // llvm.dbg.cu metadata node)
608 if (!MMI->hasDebugInfo())
611 // Finalize the debug info for the module.
612 finalizeModuleInfo();
619 // Emit info into a debug loc section.
622 // Corresponding abbreviations into a abbrev section.
625 // Emit all the DIEs into a debug info section.
628 // Emit info into a debug aranges section.
629 if (GenerateARangeSection)
632 // Emit info into a debug ranges section.
635 if (useSplitDwarf()) {
638 emitDebugAbbrevDWO();
640 // Emit DWO addresses.
641 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
644 // Emit info into the dwarf accelerator table sections.
645 if (useDwarfAccelTables()) {
648 emitAccelNamespaces();
652 // Emit the pubnames and pubtypes sections if requested.
653 if (HasDwarfPubSections) {
654 emitDebugPubNames(GenerateGnuPubSections);
655 emitDebugPubTypes(GenerateGnuPubSections);
660 AbstractVariables.clear();
663 // Find abstract variable, if any, associated with Var.
664 DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV,
665 DIVariable &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) {
676 return getExistingAbstractVariable(IV, Cleansed);
679 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
680 LexicalScope *Scope) {
681 auto AbsDbgVariable =
682 make_unique<DbgVariable>(Var, nullptr, DIExpression(), this);
683 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
684 AbstractVariables[Var] = std::move(AbsDbgVariable);
687 void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV,
688 const MDNode *ScopeNode) {
690 if (getExistingAbstractVariable(IV, Cleansed))
693 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(
694 cast<MDLocalScope>(ScopeNode)));
697 void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(
698 InlinedVariable IV, const MDNode *ScopeNode) {
700 if (getExistingAbstractVariable(IV, Cleansed))
703 if (LexicalScope *Scope =
704 LScopes.findAbstractScope(cast_or_null<MDLocalScope>(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 DIExpression Expr = cast_or_null<MDExpression>(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 MDNode *Expr = MI->getDebugExpression();
737 const MDNode *Var = MI->getDebugVariable();
739 assert(MI->getNumOperands() == 4);
740 if (MI->getOperand(0).isReg()) {
741 MachineLocation MLoc;
742 // If the second operand is an immediate, this is a
743 // register-indirect address.
744 if (!MI->getOperand(1).isImm())
745 MLoc.set(MI->getOperand(0).getReg());
747 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
748 return DebugLocEntry::Value(Var, Expr, MLoc);
750 if (MI->getOperand(0).isImm())
751 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
752 if (MI->getOperand(0).isFPImm())
753 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
754 if (MI->getOperand(0).isCImm())
755 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
757 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
760 /// Determine whether two variable pieces overlap.
761 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
762 if (!P1->isBitPiece() || !P2->isBitPiece())
764 unsigned l1 = P1->getBitPieceOffset();
765 unsigned l2 = P2->getBitPieceOffset();
766 unsigned r1 = l1 + P1->getBitPieceSize();
767 unsigned r2 = l2 + P2->getBitPieceSize();
768 // True where [l1,r1[ and [r1,r2[ overlap.
769 return (l1 < r2) && (l2 < r1);
772 /// Build the location list for all DBG_VALUEs in the function that
773 /// describe the same variable. If the ranges of several independent
774 /// pieces of the same variable overlap partially, split them up and
775 /// combine the ranges. The resulting DebugLocEntries are will have
776 /// strict monotonically increasing begin addresses and will never
781 // Ranges History [var, loc, piece ofs size]
782 // 0 | [x, (reg0, piece 0, 32)]
783 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
785 // 3 | [clobber reg0]
786 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
791 // [0-1] [x, (reg0, piece 0, 32)]
792 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
793 // [3-4] [x, (reg1, piece 32, 32)]
794 // [4- ] [x, (mem, piece 0, 64)]
796 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
797 const DbgValueHistoryMap::InstrRanges &Ranges) {
798 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
800 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
801 const MachineInstr *Begin = I->first;
802 const MachineInstr *End = I->second;
803 assert(Begin->isDebugValue() && "Invalid History entry");
805 // Check if a variable is inaccessible in this range.
806 if (Begin->getNumOperands() > 1 &&
807 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
812 // If this piece overlaps with any open ranges, truncate them.
813 DIExpression DIExpr = Begin->getDebugExpression();
814 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
815 [&](DebugLocEntry::Value R) {
816 return piecesOverlap(DIExpr, R.getExpression());
818 OpenRanges.erase(Last, OpenRanges.end());
820 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
821 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
823 const MCSymbol *EndLabel;
825 EndLabel = getLabelAfterInsn(End);
826 else if (std::next(I) == Ranges.end())
827 EndLabel = Asm->getFunctionEnd();
829 EndLabel = getLabelBeforeInsn(std::next(I)->first);
830 assert(EndLabel && "Forgot label after instruction ending a range!");
832 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
834 auto Value = getDebugLocValue(Begin);
835 DebugLocEntry Loc(StartLabel, EndLabel, Value);
836 bool couldMerge = false;
838 // If this is a piece, it may belong to the current DebugLocEntry.
839 if (DIExpr->isBitPiece()) {
840 // Add this value to the list of open ranges.
841 OpenRanges.push_back(Value);
843 // Attempt to add the piece to the last entry.
844 if (!DebugLoc.empty())
845 if (DebugLoc.back().MergeValues(Loc))
850 // Need to add a new DebugLocEntry. Add all values from still
851 // valid non-overlapping pieces.
852 if (OpenRanges.size())
853 Loc.addValues(OpenRanges);
855 DebugLoc.push_back(std::move(Loc));
858 // Attempt to coalesce the ranges of two otherwise identical
860 auto CurEntry = DebugLoc.rbegin();
861 auto PrevEntry = std::next(CurEntry);
862 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
866 dbgs() << CurEntry->getValues().size() << " Values:\n";
867 for (auto Value : CurEntry->getValues()) {
868 Value.getVariable()->dump();
869 Value.getExpression()->dump();
877 // Find variables for each lexical scope.
878 void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
879 DenseSet<InlinedVariable> &Processed) {
880 // Grab the variable info that was squirreled away in the MMI side-table.
881 collectVariableInfoFromMMITable(Processed);
883 for (const auto &I : DbgValues) {
884 InlinedVariable IV = I.first;
885 if (Processed.count(IV))
888 // Instruction ranges, specifying where IV is accessible.
889 const auto &Ranges = I.second;
893 LexicalScope *Scope = nullptr;
894 if (const MDLocation *IA = IV.second)
895 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA);
897 Scope = LScopes.findLexicalScope(IV.first->getScope());
898 // If variable scope is not found then skip this variable.
902 Processed.insert(IV);
903 const MachineInstr *MInsn = Ranges.front().first;
904 assert(MInsn->isDebugValue() && "History must begin with debug value");
905 ensureAbstractVariableIsCreatedIfScoped(IV, Scope->getScopeNode());
906 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
907 DbgVariable *RegVar = ConcreteVariables.back().get();
908 InfoHolder.addScopeVariable(Scope, RegVar);
910 // Check if the first DBG_VALUE is valid for the rest of the function.
911 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
914 // Handle multiple DBG_VALUE instructions describing one variable.
915 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
917 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
918 DebugLocList &LocList = DotDebugLocEntries.back();
920 LocList.Label = Asm->createTempSymbol("debug_loc");
922 // Build the location list for this variable.
923 buildLocationList(LocList.List, Ranges);
925 // If the variable has an MDBasicType, extract it. Basic types cannot have
926 // unique identifiers, so don't bother resolving the type with the
928 const MDBasicType *BT = dyn_cast<MDBasicType>(
929 static_cast<const Metadata *>(IV.first->getType()));
931 // Finalize the entry by lowering it into a DWARF bytestream.
932 for (auto &Entry : LocList.List)
933 Entry.finalize(*Asm, BT);
936 // Collect info for variables that were optimized out.
937 for (DIVariable DV : SP->getVariables()) {
938 if (!Processed.insert(InlinedVariable(DV, nullptr)).second)
940 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) {
941 ensureAbstractVariableIsCreatedIfScoped(InlinedVariable(DV, nullptr),
942 Scope->getScopeNode());
944 ConcreteVariables.push_back(
945 make_unique<DbgVariable>(DV, nullptr, NoExpr, this));
946 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
951 // Return Label preceding the instruction.
952 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
953 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
954 assert(Label && "Didn't insert label before instruction");
958 // Return Label immediately following the instruction.
959 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
960 return LabelsAfterInsn.lookup(MI);
963 // Process beginning of an instruction.
964 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
965 assert(CurMI == nullptr);
967 // Check if source location changes, but ignore DBG_VALUE locations.
968 if (!MI->isDebugValue()) {
969 DebugLoc DL = MI->getDebugLoc();
970 if (DL != PrevInstLoc) {
974 if (DL == PrologEndLoc) {
975 Flags |= DWARF2_FLAG_PROLOGUE_END;
976 PrologEndLoc = DebugLoc();
977 Flags |= DWARF2_FLAG_IS_STMT;
980 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
981 Flags |= DWARF2_FLAG_IS_STMT;
983 const MDNode *Scope = DL.getScope();
984 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
985 } else if (UnknownLocations) {
987 recordSourceLine(0, 0, nullptr, 0);
992 // Insert labels where requested.
993 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
994 LabelsBeforeInsn.find(MI);
997 if (I == LabelsBeforeInsn.end())
1000 // Label already assigned.
1005 PrevLabel = MMI->getContext().CreateTempSymbol();
1006 Asm->OutStreamer.EmitLabel(PrevLabel);
1008 I->second = PrevLabel;
1011 // Process end of an instruction.
1012 void DwarfDebug::endInstruction() {
1013 assert(CurMI != nullptr);
1014 // Don't create a new label after DBG_VALUE instructions.
1015 // They don't generate code.
1016 if (!CurMI->isDebugValue())
1017 PrevLabel = nullptr;
1019 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1020 LabelsAfterInsn.find(CurMI);
1024 if (I == LabelsAfterInsn.end())
1027 // Label already assigned.
1031 // We need a label after this instruction.
1033 PrevLabel = MMI->getContext().CreateTempSymbol();
1034 Asm->OutStreamer.EmitLabel(PrevLabel);
1036 I->second = PrevLabel;
1039 // Each LexicalScope has first instruction and last instruction to mark
1040 // beginning and end of a scope respectively. Create an inverse map that list
1041 // scopes starts (and ends) with an instruction. One instruction may start (or
1042 // end) multiple scopes. Ignore scopes that are not reachable.
1043 void DwarfDebug::identifyScopeMarkers() {
1044 SmallVector<LexicalScope *, 4> WorkList;
1045 WorkList.push_back(LScopes.getCurrentFunctionScope());
1046 while (!WorkList.empty()) {
1047 LexicalScope *S = WorkList.pop_back_val();
1049 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1050 if (!Children.empty())
1051 WorkList.append(Children.begin(), Children.end());
1053 if (S->isAbstractScope())
1056 for (const InsnRange &R : S->getRanges()) {
1057 assert(R.first && "InsnRange does not have first instruction!");
1058 assert(R.second && "InsnRange does not have second instruction!");
1059 requestLabelBeforeInsn(R.first);
1060 requestLabelAfterInsn(R.second);
1065 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1066 // First known non-DBG_VALUE and non-frame setup location marks
1067 // the beginning of the function body.
1068 for (const auto &MBB : *MF)
1069 for (const auto &MI : MBB)
1070 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1072 // Did the target forget to set the FrameSetup flag for CFI insns?
1073 assert(!MI.isCFIInstruction() &&
1074 "First non-frame-setup instruction is a CFI instruction.");
1075 return MI.getDebugLoc();
1080 // Gather pre-function debug information. Assumes being called immediately
1081 // after the function entry point has been emitted.
1082 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1085 // If there's no debug info for the function we're not going to do anything.
1086 if (!MMI->hasDebugInfo())
1089 auto DI = FunctionDIs.find(MF->getFunction());
1090 if (DI == FunctionDIs.end())
1093 // Grab the lexical scopes for the function, if we don't have any of those
1094 // then we're not going to be able to do anything.
1095 LScopes.initialize(*MF);
1096 if (LScopes.empty())
1099 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1101 // Make sure that each lexical scope will have a begin/end label.
1102 identifyScopeMarkers();
1104 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1105 // belongs to so that we add to the correct per-cu line table in the
1107 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1108 // FnScope->getScopeNode() and DI->second should represent the same function,
1109 // though they may not be the same MDNode due to inline functions merged in
1110 // LTO where the debug info metadata still differs (either due to distinct
1111 // written differences - two versions of a linkonce_odr function
1112 // written/copied into two separate files, or some sub-optimal metadata that
1113 // isn't structurally identical (see: file path/name info from clang, which
1114 // includes the directory of the cpp file being built, even when the file name
1115 // is absolute (such as an <> lookup header)))
1116 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1117 assert(TheCU && "Unable to find compile unit!");
1118 if (Asm->OutStreamer.hasRawTextSupport())
1119 // Use a single line table if we are generating assembly.
1120 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1122 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1124 // Calculate history for local variables.
1125 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1128 // Request labels for the full history.
1129 for (const auto &I : DbgValues) {
1130 const auto &Ranges = I.second;
1134 // The first mention of a function argument gets the CurrentFnBegin
1135 // label, so arguments are visible when breaking at function entry.
1136 DIVariable DIVar = Ranges.front().first->getDebugVariable();
1137 if (DIVar->getTag() == dwarf::DW_TAG_arg_variable &&
1138 getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) {
1139 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin();
1140 if (Ranges.front().first->getDebugExpression()->isBitPiece()) {
1141 // Mark all non-overlapping initial pieces.
1142 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1143 DIExpression Piece = I->first->getDebugExpression();
1144 if (std::all_of(Ranges.begin(), I,
1145 [&](DbgValueHistoryMap::InstrRange Pred) {
1146 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1148 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
1155 for (const auto &Range : Ranges) {
1156 requestLabelBeforeInsn(Range.first);
1158 requestLabelAfterInsn(Range.second);
1162 PrevInstLoc = DebugLoc();
1163 PrevLabel = Asm->getFunctionBegin();
1165 // Record beginning of function.
1166 PrologEndLoc = findPrologueEndLoc(MF);
1167 if (MDLocation *L = PrologEndLoc) {
1168 // We'd like to list the prologue as "not statements" but GDB behaves
1169 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1170 auto *SP = L->getInlinedAtScope()->getSubprogram();
1171 recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT);
1175 // Gather and emit post-function debug information.
1176 void DwarfDebug::endFunction(const MachineFunction *MF) {
1177 assert(CurFn == MF &&
1178 "endFunction should be called with the same function as beginFunction");
1180 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1181 !FunctionDIs.count(MF->getFunction())) {
1182 // If we don't have a lexical scope for this function then there will
1183 // be a hole in the range information. Keep note of this by setting the
1184 // previously used section to nullptr.
1190 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1191 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1193 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1194 DISubprogram SP = cast<MDSubprogram>(FnScope->getScopeNode());
1195 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1197 DenseSet<InlinedVariable> ProcessedVars;
1198 collectVariableInfo(TheCU, SP, ProcessedVars);
1200 // Add the range of this function to the list of ranges for the CU.
1201 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd()));
1203 // Under -gmlt, skip building the subprogram if there are no inlined
1204 // subroutines inside it.
1205 if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly &&
1206 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1207 assert(InfoHolder.getScopeVariables().empty());
1208 assert(DbgValues.empty());
1209 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1210 // by a -gmlt CU. Add a test and remove this assertion.
1211 assert(AbstractVariables.empty());
1212 LabelsBeforeInsn.clear();
1213 LabelsAfterInsn.clear();
1214 PrevLabel = nullptr;
1220 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1222 // Construct abstract scopes.
1223 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1224 DISubprogram SP = cast<MDSubprogram>(AScope->getScopeNode());
1225 // Collect info for variables that were optimized out.
1226 for (DIVariable DV : SP->getVariables()) {
1227 if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second)
1229 ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr),
1231 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1232 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1234 constructAbstractSubprogramScopeDIE(AScope);
1237 TheCU.constructSubprogramScopeDIE(FnScope);
1238 if (auto *SkelCU = TheCU.getSkeleton())
1239 if (!LScopes.getAbstractScopesList().empty())
1240 SkelCU->constructSubprogramScopeDIE(FnScope);
1243 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1244 // DbgVariables except those that are also in AbstractVariables (since they
1245 // can be used cross-function)
1246 InfoHolder.getScopeVariables().clear();
1248 LabelsBeforeInsn.clear();
1249 LabelsAfterInsn.clear();
1250 PrevLabel = nullptr;
1254 // Register a source line with debug info. Returns the unique label that was
1255 // emitted and which provides correspondence to the source line list.
1256 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1261 unsigned Discriminator = 0;
1262 if (auto *Scope = cast_or_null<MDScope>(S)) {
1263 Fn = Scope->getFilename();
1264 Dir = Scope->getDirectory();
1265 if (auto *LBF = dyn_cast<MDLexicalBlockFile>(Scope))
1266 Discriminator = LBF->getDiscriminator();
1268 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1269 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1270 .getOrCreateSourceID(Fn, Dir);
1272 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1276 //===----------------------------------------------------------------------===//
1278 //===----------------------------------------------------------------------===//
1280 // Emit the debug info section.
1281 void DwarfDebug::emitDebugInfo() {
1282 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1283 Holder.emitUnits(/* UseOffsets */ false);
1286 // Emit the abbreviation section.
1287 void DwarfDebug::emitAbbreviations() {
1288 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1290 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1293 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1294 StringRef TableName) {
1295 Accel.FinalizeTable(Asm, TableName);
1296 Asm->OutStreamer.SwitchSection(Section);
1298 // Emit the full data.
1299 Accel.emit(Asm, Section->getBeginSymbol(), this);
1302 // Emit visible names into a hashed accelerator table section.
1303 void DwarfDebug::emitAccelNames() {
1304 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1308 // Emit objective C classes and categories into a hashed accelerator table
1310 void DwarfDebug::emitAccelObjC() {
1311 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1315 // Emit namespace dies into a hashed accelerator table.
1316 void DwarfDebug::emitAccelNamespaces() {
1317 emitAccel(AccelNamespace,
1318 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1322 // Emit type dies into a hashed accelerator table.
1323 void DwarfDebug::emitAccelTypes() {
1324 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1328 // Public name handling.
1329 // The format for the various pubnames:
1331 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1332 // for the DIE that is named.
1334 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1335 // into the CU and the index value is computed according to the type of value
1336 // for the DIE that is named.
1338 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1339 // it's the offset within the debug_info/debug_types dwo section, however, the
1340 // reference in the pubname header doesn't change.
1342 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1343 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1345 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1347 // We could have a specification DIE that has our most of our knowledge,
1348 // look for that now.
1349 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1351 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1352 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1353 Linkage = dwarf::GIEL_EXTERNAL;
1354 } else if (Die->findAttribute(dwarf::DW_AT_external))
1355 Linkage = dwarf::GIEL_EXTERNAL;
1357 switch (Die->getTag()) {
1358 case dwarf::DW_TAG_class_type:
1359 case dwarf::DW_TAG_structure_type:
1360 case dwarf::DW_TAG_union_type:
1361 case dwarf::DW_TAG_enumeration_type:
1362 return dwarf::PubIndexEntryDescriptor(
1363 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1364 ? dwarf::GIEL_STATIC
1365 : dwarf::GIEL_EXTERNAL);
1366 case dwarf::DW_TAG_typedef:
1367 case dwarf::DW_TAG_base_type:
1368 case dwarf::DW_TAG_subrange_type:
1369 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1370 case dwarf::DW_TAG_namespace:
1371 return dwarf::GIEK_TYPE;
1372 case dwarf::DW_TAG_subprogram:
1373 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1374 case dwarf::DW_TAG_variable:
1375 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1376 case dwarf::DW_TAG_enumerator:
1377 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1378 dwarf::GIEL_STATIC);
1380 return dwarf::GIEK_NONE;
1384 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1386 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1387 const MCSection *PSec =
1388 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1389 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1391 emitDebugPubSection(GnuStyle, PSec, "Names",
1392 &DwarfCompileUnit::getGlobalNames);
1395 void DwarfDebug::emitDebugPubSection(
1396 bool GnuStyle, const MCSection *PSec, StringRef Name,
1397 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1398 for (const auto &NU : CUMap) {
1399 DwarfCompileUnit *TheU = NU.second;
1401 const auto &Globals = (TheU->*Accessor)();
1403 if (Globals.empty())
1406 if (auto *Skeleton = TheU->getSkeleton())
1409 // Start the dwarf pubnames section.
1410 Asm->OutStreamer.SwitchSection(PSec);
1413 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1414 MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin");
1415 MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end");
1416 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1418 Asm->OutStreamer.EmitLabel(BeginLabel);
1420 Asm->OutStreamer.AddComment("DWARF Version");
1421 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1423 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1424 Asm->emitSectionOffset(TheU->getLabelBegin());
1426 Asm->OutStreamer.AddComment("Compilation Unit Length");
1427 Asm->EmitInt32(TheU->getLength());
1429 // Emit the pubnames for this compilation unit.
1430 for (const auto &GI : Globals) {
1431 const char *Name = GI.getKeyData();
1432 const DIE *Entity = GI.second;
1434 Asm->OutStreamer.AddComment("DIE offset");
1435 Asm->EmitInt32(Entity->getOffset());
1438 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1439 Asm->OutStreamer.AddComment(
1440 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1441 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1442 Asm->EmitInt8(Desc.toBits());
1445 Asm->OutStreamer.AddComment("External Name");
1446 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1449 Asm->OutStreamer.AddComment("End Mark");
1451 Asm->OutStreamer.EmitLabel(EndLabel);
1455 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1456 const MCSection *PSec =
1457 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1458 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1460 emitDebugPubSection(GnuStyle, PSec, "Types",
1461 &DwarfCompileUnit::getGlobalTypes);
1464 // Emit visible names into a debug str section.
1465 void DwarfDebug::emitDebugStr() {
1466 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1467 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1471 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1472 const DebugLocEntry &Entry) {
1473 auto Comment = Entry.getComments().begin();
1474 auto End = Entry.getComments().end();
1475 for (uint8_t Byte : Entry.getDWARFBytes())
1476 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1479 static void emitDebugLocValue(const AsmPrinter &AP, const MDBasicType *BT,
1480 ByteStreamer &Streamer,
1481 const DebugLocEntry::Value &Value,
1482 unsigned PieceOffsetInBits) {
1483 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(),
1484 AP.getDwarfDebug()->getDwarfVersion(),
1487 if (Value.isInt()) {
1488 if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed ||
1489 BT->getEncoding() == dwarf::DW_ATE_signed_char))
1490 DwarfExpr.AddSignedConstant(Value.getInt());
1492 DwarfExpr.AddUnsignedConstant(Value.getInt());
1493 } else if (Value.isLocation()) {
1494 MachineLocation Loc = Value.getLoc();
1495 DIExpression Expr = Value.getExpression();
1496 if (!Expr || !Expr->getNumElements())
1498 AP.EmitDwarfRegOp(Streamer, Loc);
1500 // Complex address entry.
1501 if (Loc.getOffset()) {
1502 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1503 DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(),
1506 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1510 // else ... ignore constant fp. There is not any good way to
1511 // to represent them here in dwarf.
1515 void DebugLocEntry::finalize(const AsmPrinter &AP, const MDBasicType *BT) {
1516 BufferByteStreamer Streamer(DWARFBytes, Comments);
1517 const DebugLocEntry::Value Value = Values[0];
1518 if (Value.isBitPiece()) {
1519 // Emit all pieces that belong to the same variable and range.
1520 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1521 return P.isBitPiece();
1522 }) && "all values are expected to be pieces");
1523 assert(std::is_sorted(Values.begin(), Values.end()) &&
1524 "pieces are expected to be sorted");
1526 unsigned Offset = 0;
1527 for (auto Piece : Values) {
1528 DIExpression Expr = Piece.getExpression();
1529 unsigned PieceOffset = Expr->getBitPieceOffset();
1530 unsigned PieceSize = Expr->getBitPieceSize();
1531 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1532 if (Offset < PieceOffset) {
1533 // The DWARF spec seriously mandates pieces with no locations for gaps.
1534 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(),
1535 AP.getDwarfDebug()->getDwarfVersion(),
1537 Expr.AddOpPiece(PieceOffset-Offset, 0);
1538 Offset += PieceOffset-Offset;
1540 Offset += PieceSize;
1542 emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset);
1545 assert(Values.size() == 1 && "only pieces may have >1 value");
1546 emitDebugLocValue(AP, BT, Streamer, Value, 0);
1551 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1552 Asm->OutStreamer.AddComment("Loc expr size");
1553 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1554 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1555 Asm->EmitLabelDifference(end, begin, 2);
1556 Asm->OutStreamer.EmitLabel(begin);
1558 APByteStreamer Streamer(*Asm);
1559 emitDebugLocEntry(Streamer, Entry);
1561 Asm->OutStreamer.EmitLabel(end);
1564 // Emit locations into the debug loc section.
1565 void DwarfDebug::emitDebugLoc() {
1566 // Start the dwarf loc section.
1567 Asm->OutStreamer.SwitchSection(
1568 Asm->getObjFileLowering().getDwarfLocSection());
1569 unsigned char Size = Asm->getDataLayout().getPointerSize();
1570 for (const auto &DebugLoc : DotDebugLocEntries) {
1571 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1572 const DwarfCompileUnit *CU = DebugLoc.CU;
1573 for (const auto &Entry : DebugLoc.List) {
1574 // Set up the range. This range is relative to the entry point of the
1575 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1576 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1577 if (auto *Base = CU->getBaseAddress()) {
1578 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1579 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1581 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1582 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1585 emitDebugLocEntryLocation(Entry);
1587 Asm->OutStreamer.EmitIntValue(0, Size);
1588 Asm->OutStreamer.EmitIntValue(0, Size);
1592 void DwarfDebug::emitDebugLocDWO() {
1593 Asm->OutStreamer.SwitchSection(
1594 Asm->getObjFileLowering().getDwarfLocDWOSection());
1595 for (const auto &DebugLoc : DotDebugLocEntries) {
1596 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1597 for (const auto &Entry : DebugLoc.List) {
1598 // Just always use start_length for now - at least that's one address
1599 // rather than two. We could get fancier and try to, say, reuse an
1600 // address we know we've emitted elsewhere (the start of the function?
1601 // The start of the CU or CU subrange that encloses this range?)
1602 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1603 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1604 Asm->EmitULEB128(idx);
1605 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1607 emitDebugLocEntryLocation(Entry);
1609 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1614 const MCSymbol *Start, *End;
1617 // Emit a debug aranges section, containing a CU lookup for any
1618 // address we can tie back to a CU.
1619 void DwarfDebug::emitDebugARanges() {
1620 // Provides a unique id per text section.
1621 MapVector<const MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1623 // Filter labels by section.
1624 for (const SymbolCU &SCU : ArangeLabels) {
1625 if (SCU.Sym->isInSection()) {
1626 // Make a note of this symbol and it's section.
1627 const MCSection *Section = &SCU.Sym->getSection();
1628 if (!Section->getKind().isMetadata())
1629 SectionMap[Section].push_back(SCU);
1631 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1632 // appear in the output. This sucks as we rely on sections to build
1633 // arange spans. We can do it without, but it's icky.
1634 SectionMap[nullptr].push_back(SCU);
1638 // Add terminating symbols for each section.
1639 for (const auto &I : SectionMap) {
1640 const MCSection *Section = I.first;
1641 MCSymbol *Sym = nullptr;
1644 Sym = Asm->OutStreamer.endSection(Section);
1646 // Insert a final terminator.
1647 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1650 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1652 for (auto &I : SectionMap) {
1653 const MCSection *Section = I.first;
1654 SmallVector<SymbolCU, 8> &List = I.second;
1655 if (List.size() < 2)
1658 // If we have no section (e.g. common), just write out
1659 // individual spans for each symbol.
1661 for (const SymbolCU &Cur : List) {
1663 Span.Start = Cur.Sym;
1666 Spans[Cur.CU].push_back(Span);
1671 // Sort the symbols by offset within the section.
1672 std::sort(List.begin(), List.end(),
1673 [&](const SymbolCU &A, const SymbolCU &B) {
1674 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1675 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1677 // Symbols with no order assigned should be placed at the end.
1678 // (e.g. section end labels)
1686 // Build spans between each label.
1687 const MCSymbol *StartSym = List[0].Sym;
1688 for (size_t n = 1, e = List.size(); n < e; n++) {
1689 const SymbolCU &Prev = List[n - 1];
1690 const SymbolCU &Cur = List[n];
1692 // Try and build the longest span we can within the same CU.
1693 if (Cur.CU != Prev.CU) {
1695 Span.Start = StartSym;
1697 Spans[Prev.CU].push_back(Span);
1703 // Start the dwarf aranges section.
1704 Asm->OutStreamer.SwitchSection(
1705 Asm->getObjFileLowering().getDwarfARangesSection());
1707 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1709 // Build a list of CUs used.
1710 std::vector<DwarfCompileUnit *> CUs;
1711 for (const auto &it : Spans) {
1712 DwarfCompileUnit *CU = it.first;
1716 // Sort the CU list (again, to ensure consistent output order).
1717 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1718 return A->getUniqueID() < B->getUniqueID();
1721 // Emit an arange table for each CU we used.
1722 for (DwarfCompileUnit *CU : CUs) {
1723 std::vector<ArangeSpan> &List = Spans[CU];
1725 // Describe the skeleton CU's offset and length, not the dwo file's.
1726 if (auto *Skel = CU->getSkeleton())
1729 // Emit size of content not including length itself.
1730 unsigned ContentSize =
1731 sizeof(int16_t) + // DWARF ARange version number
1732 sizeof(int32_t) + // Offset of CU in the .debug_info section
1733 sizeof(int8_t) + // Pointer Size (in bytes)
1734 sizeof(int8_t); // Segment Size (in bytes)
1736 unsigned TupleSize = PtrSize * 2;
1738 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1740 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1742 ContentSize += Padding;
1743 ContentSize += (List.size() + 1) * TupleSize;
1745 // For each compile unit, write the list of spans it covers.
1746 Asm->OutStreamer.AddComment("Length of ARange Set");
1747 Asm->EmitInt32(ContentSize);
1748 Asm->OutStreamer.AddComment("DWARF Arange version number");
1749 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1750 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1751 Asm->emitSectionOffset(CU->getLabelBegin());
1752 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1753 Asm->EmitInt8(PtrSize);
1754 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1757 Asm->OutStreamer.EmitFill(Padding, 0xff);
1759 for (const ArangeSpan &Span : List) {
1760 Asm->EmitLabelReference(Span.Start, PtrSize);
1762 // Calculate the size as being from the span start to it's end.
1764 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1766 // For symbols without an end marker (e.g. common), we
1767 // write a single arange entry containing just that one symbol.
1768 uint64_t Size = SymSize[Span.Start];
1772 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1776 Asm->OutStreamer.AddComment("ARange terminator");
1777 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1778 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1782 // Emit visible names into a debug ranges section.
1783 void DwarfDebug::emitDebugRanges() {
1784 // Start the dwarf ranges section.
1785 Asm->OutStreamer.SwitchSection(
1786 Asm->getObjFileLowering().getDwarfRangesSection());
1788 // Size for our labels.
1789 unsigned char Size = Asm->getDataLayout().getPointerSize();
1791 // Grab the specific ranges for the compile units in the module.
1792 for (const auto &I : CUMap) {
1793 DwarfCompileUnit *TheCU = I.second;
1795 if (auto *Skel = TheCU->getSkeleton())
1798 // Iterate over the misc ranges for the compile units in the module.
1799 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1800 // Emit our symbol so we can find the beginning of the range.
1801 Asm->OutStreamer.EmitLabel(List.getSym());
1803 for (const RangeSpan &Range : List.getRanges()) {
1804 const MCSymbol *Begin = Range.getStart();
1805 const MCSymbol *End = Range.getEnd();
1806 assert(Begin && "Range without a begin symbol?");
1807 assert(End && "Range without an end symbol?");
1808 if (auto *Base = TheCU->getBaseAddress()) {
1809 Asm->EmitLabelDifference(Begin, Base, Size);
1810 Asm->EmitLabelDifference(End, Base, Size);
1812 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1813 Asm->OutStreamer.EmitSymbolValue(End, Size);
1817 // And terminate the list with two 0 values.
1818 Asm->OutStreamer.EmitIntValue(0, Size);
1819 Asm->OutStreamer.EmitIntValue(0, Size);
1824 // DWARF5 Experimental Separate Dwarf emitters.
1826 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1827 std::unique_ptr<DwarfUnit> NewU) {
1828 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1829 U.getCUNode()->getSplitDebugFilename());
1831 if (!CompilationDir.empty())
1832 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1834 addGnuPubAttributes(*NewU, Die);
1836 SkeletonHolder.addUnit(std::move(NewU));
1839 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1840 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1841 // DW_AT_addr_base, DW_AT_ranges_base.
1842 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1844 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1845 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1846 DwarfCompileUnit &NewCU = *OwnedUnit;
1847 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1849 NewCU.initStmtList();
1851 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1856 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1857 // compile units that would normally be in debug_info.
1858 void DwarfDebug::emitDebugInfoDWO() {
1859 assert(useSplitDwarf() && "No split dwarf debug info?");
1860 // Don't emit relocations into the dwo file.
1861 InfoHolder.emitUnits(/* UseOffsets */ true);
1864 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1865 // abbreviations for the .debug_info.dwo section.
1866 void DwarfDebug::emitDebugAbbrevDWO() {
1867 assert(useSplitDwarf() && "No split dwarf?");
1868 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1871 void DwarfDebug::emitDebugLineDWO() {
1872 assert(useSplitDwarf() && "No split dwarf?");
1873 Asm->OutStreamer.SwitchSection(
1874 Asm->getObjFileLowering().getDwarfLineDWOSection());
1875 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
1878 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1879 // string section and is identical in format to traditional .debug_str
1881 void DwarfDebug::emitDebugStrDWO() {
1882 assert(useSplitDwarf() && "No split dwarf?");
1883 const MCSection *OffSec =
1884 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1885 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1889 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1890 if (!useSplitDwarf())
1893 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory());
1894 return &SplitTypeUnitFileTable;
1897 static uint64_t makeTypeSignature(StringRef Identifier) {
1899 Hash.update(Identifier);
1900 // ... take the least significant 8 bytes and return those. Our MD5
1901 // implementation always returns its results in little endian, swap bytes
1903 MD5::MD5Result Result;
1905 return support::endian::read64le(Result + 8);
1908 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1909 StringRef Identifier, DIE &RefDie,
1910 DICompositeType CTy) {
1911 // Fast path if we're building some type units and one has already used the
1912 // address pool we know we're going to throw away all this work anyway, so
1913 // don't bother building dependent types.
1914 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1917 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1919 CU.addDIETypeSignature(RefDie, *TU);
1923 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1924 AddrPool.resetUsedFlag();
1926 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1927 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1928 this, &InfoHolder, getDwoLineTable(CU));
1929 DwarfTypeUnit &NewTU = *OwnedUnit;
1930 DIE &UnitDie = NewTU.getUnitDie();
1932 TypeUnitsUnderConstruction.push_back(
1933 std::make_pair(std::move(OwnedUnit), CTy));
1935 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1938 uint64_t Signature = makeTypeSignature(Identifier);
1939 NewTU.setTypeSignature(Signature);
1941 if (useSplitDwarf())
1942 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
1944 CU.applyStmtList(UnitDie);
1946 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
1949 NewTU.setType(NewTU.createTypeDIE(CTy));
1952 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
1953 TypeUnitsUnderConstruction.clear();
1955 // Types referencing entries in the address table cannot be placed in type
1957 if (AddrPool.hasBeenUsed()) {
1959 // Remove all the types built while building this type.
1960 // This is pessimistic as some of these types might not be dependent on
1961 // the type that used an address.
1962 for (const auto &TU : TypeUnitsToAdd)
1963 DwarfTypeUnits.erase(TU.second);
1965 // Construct this type in the CU directly.
1966 // This is inefficient because all the dependent types will be rebuilt
1967 // from scratch, including building them in type units, discovering that
1968 // they depend on addresses, throwing them out and rebuilding them.
1969 CU.constructTypeDIE(RefDie, CTy);
1973 // If the type wasn't dependent on fission addresses, finish adding the type
1974 // and all its dependent types.
1975 for (auto &TU : TypeUnitsToAdd)
1976 InfoHolder.addUnit(std::move(TU.first));
1978 CU.addDIETypeSignature(RefDie, NewTU);
1981 // Accelerator table mutators - add each name along with its companion
1982 // DIE to the proper table while ensuring that the name that we're going
1983 // to reference is in the string table. We do this since the names we
1984 // add may not only be identical to the names in the DIE.
1985 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
1986 if (!useDwarfAccelTables())
1988 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1992 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
1993 if (!useDwarfAccelTables())
1995 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1999 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2000 if (!useDwarfAccelTables())
2002 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2006 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2007 if (!useDwarfAccelTables())
2009 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),