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(const MDSubprogram *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.
367 DwarfDebug::constructDwarfCompileUnit(const MDCompileUnit *DIUnit) {
368 StringRef FN = DIUnit->getFilename();
369 CompilationDir = DIUnit->getDirectory();
371 auto OwnedUnit = make_unique<DwarfCompileUnit>(
372 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
373 DwarfCompileUnit &NewCU = *OwnedUnit;
374 DIE &Die = NewCU.getUnitDie();
375 InfoHolder.addUnit(std::move(OwnedUnit));
377 NewCU.setSkeleton(constructSkeletonCU(NewCU));
379 // LTO with assembly output shares a single line table amongst multiple CUs.
380 // To avoid the compilation directory being ambiguous, let the line table
381 // explicitly describe the directory of all files, never relying on the
382 // compilation directory.
383 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
384 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
385 NewCU.getUniqueID(), CompilationDir);
387 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer());
388 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
389 DIUnit->getSourceLanguage());
390 NewCU.addString(Die, dwarf::DW_AT_name, FN);
392 if (!useSplitDwarf()) {
393 NewCU.initStmtList();
395 // If we're using split dwarf the compilation dir is going to be in the
396 // skeleton CU and so we don't need to duplicate it here.
397 if (!CompilationDir.empty())
398 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
400 addGnuPubAttributes(NewCU, Die);
403 if (DIUnit->isOptimized())
404 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
406 StringRef Flags = DIUnit->getFlags();
408 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
410 if (unsigned RVer = DIUnit->getRuntimeVersion())
411 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
412 dwarf::DW_FORM_data1, RVer);
415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
417 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
419 CUMap.insert(std::make_pair(DIUnit, &NewCU));
420 CUDieMap.insert(std::make_pair(&Die, &NewCU));
424 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
426 DIImportedEntity Module = cast<MDImportedEntity>(N);
427 if (DIE *D = TheCU.getOrCreateContextDIE(Module->getScope()))
428 D->addChild(TheCU.constructImportedEntityDIE(Module));
431 // Emit all Dwarf sections that should come prior to the content. Create
432 // global DIEs and emit initial debug info sections. This is invoked by
433 // the target AsmPrinter.
434 void DwarfDebug::beginModule() {
435 if (DisableDebugInfoPrinting)
438 const Module *M = MMI->getModule();
440 FunctionDIs = makeSubprogramMap(*M);
442 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
445 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
447 SingleCU = CU_Nodes->getNumOperands() == 1;
449 for (MDNode *N : CU_Nodes->operands()) {
450 auto *CUNode = cast<MDCompileUnit>(N);
451 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
452 for (auto *IE : CUNode->getImportedEntities())
453 ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE));
454 // Stable sort to preserve the order of appearance of imported entities.
455 // This is to avoid out-of-order processing of interdependent declarations
456 // within the same scope, e.g. { namespace A = base; namespace B = A; }
457 std::stable_sort(ScopesWithImportedEntities.begin(),
458 ScopesWithImportedEntities.end(), less_first());
459 for (auto *GV : CUNode->getGlobalVariables())
460 CU.getOrCreateGlobalVariableDIE(GV);
461 for (auto *SP : CUNode->getSubprograms())
462 SPMap.insert(std::make_pair(SP, &CU));
463 for (auto *Ty : CUNode->getEnumTypes()) {
464 // The enum types array by design contains pointers to
465 // MDNodes rather than DIRefs. Unique them here.
466 CU.getOrCreateTypeDIE(cast<MDType>(resolve(Ty->getRef())));
468 for (auto *Ty : CUNode->getRetainedTypes()) {
469 // The retained types array by design contains pointers to
470 // MDNodes rather than DIRefs. Unique them here.
471 CU.getOrCreateTypeDIE(cast<MDType>(resolve(Ty->getRef())));
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 auto *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 MDExpression *Expr = MI->getDebugExpression();
738 assert(MI->getNumOperands() == 4);
739 if (MI->getOperand(0).isReg()) {
740 MachineLocation MLoc;
741 // If the second operand is an immediate, this is a
742 // register-indirect address.
743 if (!MI->getOperand(1).isImm())
744 MLoc.set(MI->getOperand(0).getReg());
746 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
747 return DebugLocEntry::Value(Expr, MLoc);
749 if (MI->getOperand(0).isImm())
750 return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm());
751 if (MI->getOperand(0).isFPImm())
752 return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm());
753 if (MI->getOperand(0).isCImm())
754 return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm());
756 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
759 /// Determine whether two variable pieces overlap.
760 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
761 if (!P1->isBitPiece() || !P2->isBitPiece())
763 unsigned l1 = P1->getBitPieceOffset();
764 unsigned l2 = P2->getBitPieceOffset();
765 unsigned r1 = l1 + P1->getBitPieceSize();
766 unsigned r2 = l2 + P2->getBitPieceSize();
767 // True where [l1,r1[ and [r1,r2[ overlap.
768 return (l1 < r2) && (l2 < r1);
771 /// Build the location list for all DBG_VALUEs in the function that
772 /// describe the same variable. If the ranges of several independent
773 /// pieces of the same variable overlap partially, split them up and
774 /// combine the ranges. The resulting DebugLocEntries are will have
775 /// strict monotonically increasing begin addresses and will never
780 // Ranges History [var, loc, piece ofs size]
781 // 0 | [x, (reg0, piece 0, 32)]
782 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
784 // 3 | [clobber reg0]
785 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
790 // [0-1] [x, (reg0, piece 0, 32)]
791 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
792 // [3-4] [x, (reg1, piece 32, 32)]
793 // [4- ] [x, (mem, piece 0, 64)]
795 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
796 const DbgValueHistoryMap::InstrRanges &Ranges) {
797 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
799 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
800 const MachineInstr *Begin = I->first;
801 const MachineInstr *End = I->second;
802 assert(Begin->isDebugValue() && "Invalid History entry");
804 // Check if a variable is inaccessible in this range.
805 if (Begin->getNumOperands() > 1 &&
806 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
811 // If this piece overlaps with any open ranges, truncate them.
812 DIExpression DIExpr = Begin->getDebugExpression();
813 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
814 [&](DebugLocEntry::Value R) {
815 return piecesOverlap(DIExpr, R.getExpression());
817 OpenRanges.erase(Last, OpenRanges.end());
819 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
820 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
822 const MCSymbol *EndLabel;
824 EndLabel = getLabelAfterInsn(End);
825 else if (std::next(I) == Ranges.end())
826 EndLabel = Asm->getFunctionEnd();
828 EndLabel = getLabelBeforeInsn(std::next(I)->first);
829 assert(EndLabel && "Forgot label after instruction ending a range!");
831 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
833 auto Value = getDebugLocValue(Begin);
834 DebugLocEntry Loc(StartLabel, EndLabel, Value);
835 bool couldMerge = false;
837 // If this is a piece, it may belong to the current DebugLocEntry.
838 if (DIExpr->isBitPiece()) {
839 // Add this value to the list of open ranges.
840 OpenRanges.push_back(Value);
842 // Attempt to add the piece to the last entry.
843 if (!DebugLoc.empty())
844 if (DebugLoc.back().MergeValues(Loc))
849 // Need to add a new DebugLocEntry. Add all values from still
850 // valid non-overlapping pieces.
851 if (OpenRanges.size())
852 Loc.addValues(OpenRanges);
854 DebugLoc.push_back(std::move(Loc));
857 // Attempt to coalesce the ranges of two otherwise identical
859 auto CurEntry = DebugLoc.rbegin();
860 auto PrevEntry = std::next(CurEntry);
861 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
865 dbgs() << CurEntry->getValues().size() << " Values:\n";
866 for (auto Value : CurEntry->getValues()) {
867 Value.getExpression()->dump();
875 // Find variables for each lexical scope.
876 void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU,
877 const MDSubprogram *SP,
878 DenseSet<InlinedVariable> &Processed) {
879 // Grab the variable info that was squirreled away in the MMI side-table.
880 collectVariableInfoFromMMITable(Processed);
882 for (const auto &I : DbgValues) {
883 InlinedVariable IV = I.first;
884 if (Processed.count(IV))
887 // Instruction ranges, specifying where IV is accessible.
888 const auto &Ranges = I.second;
892 LexicalScope *Scope = nullptr;
893 if (const MDLocation *IA = IV.second)
894 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA);
896 Scope = LScopes.findLexicalScope(IV.first->getScope());
897 // If variable scope is not found then skip this variable.
901 Processed.insert(IV);
902 const MachineInstr *MInsn = Ranges.front().first;
903 assert(MInsn->isDebugValue() && "History must begin with debug value");
904 ensureAbstractVariableIsCreatedIfScoped(IV, Scope->getScopeNode());
905 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
906 DbgVariable *RegVar = ConcreteVariables.back().get();
907 InfoHolder.addScopeVariable(Scope, RegVar);
909 // Check if the first DBG_VALUE is valid for the rest of the function.
910 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
913 // Handle multiple DBG_VALUE instructions describing one variable.
914 RegVar->setDebugLocListIndex(
915 DebugLocs.startList(&TheCU, Asm->createTempSymbol("debug_loc")));
917 // Build the location list for this variable.
918 SmallVector<DebugLocEntry, 8> Entries;
919 buildLocationList(Entries, Ranges);
921 // If the variable has an MDBasicType, extract it. Basic types cannot have
922 // unique identifiers, so don't bother resolving the type with the
924 const MDBasicType *BT = dyn_cast<MDBasicType>(
925 static_cast<const Metadata *>(IV.first->getType()));
927 // Finalize the entry by lowering it into a DWARF bytestream.
928 for (auto &Entry : Entries)
929 Entry.finalize(*Asm, DebugLocs, BT);
932 // Collect info for variables that were optimized out.
933 for (DIVariable DV : SP->getVariables()) {
934 if (!Processed.insert(InlinedVariable(DV, nullptr)).second)
936 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) {
937 ensureAbstractVariableIsCreatedIfScoped(InlinedVariable(DV, nullptr),
938 Scope->getScopeNode());
940 ConcreteVariables.push_back(
941 make_unique<DbgVariable>(DV, nullptr, NoExpr, this));
942 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
947 // Return Label preceding the instruction.
948 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
949 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
950 assert(Label && "Didn't insert label before instruction");
954 // Return Label immediately following the instruction.
955 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
956 return LabelsAfterInsn.lookup(MI);
959 // Process beginning of an instruction.
960 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
961 assert(CurMI == nullptr);
963 // Check if source location changes, but ignore DBG_VALUE locations.
964 if (!MI->isDebugValue()) {
965 DebugLoc DL = MI->getDebugLoc();
966 if (DL != PrevInstLoc) {
970 if (DL == PrologEndLoc) {
971 Flags |= DWARF2_FLAG_PROLOGUE_END;
972 PrologEndLoc = DebugLoc();
973 Flags |= DWARF2_FLAG_IS_STMT;
976 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
977 Flags |= DWARF2_FLAG_IS_STMT;
979 const MDNode *Scope = DL.getScope();
980 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
981 } else if (UnknownLocations) {
983 recordSourceLine(0, 0, nullptr, 0);
988 // Insert labels where requested.
989 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
990 LabelsBeforeInsn.find(MI);
993 if (I == LabelsBeforeInsn.end())
996 // Label already assigned.
1001 PrevLabel = MMI->getContext().CreateTempSymbol();
1002 Asm->OutStreamer.EmitLabel(PrevLabel);
1004 I->second = PrevLabel;
1007 // Process end of an instruction.
1008 void DwarfDebug::endInstruction() {
1009 assert(CurMI != nullptr);
1010 // Don't create a new label after DBG_VALUE instructions.
1011 // They don't generate code.
1012 if (!CurMI->isDebugValue())
1013 PrevLabel = nullptr;
1015 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1016 LabelsAfterInsn.find(CurMI);
1020 if (I == LabelsAfterInsn.end())
1023 // Label already assigned.
1027 // We need a label after this instruction.
1029 PrevLabel = MMI->getContext().CreateTempSymbol();
1030 Asm->OutStreamer.EmitLabel(PrevLabel);
1032 I->second = PrevLabel;
1035 // Each LexicalScope has first instruction and last instruction to mark
1036 // beginning and end of a scope respectively. Create an inverse map that list
1037 // scopes starts (and ends) with an instruction. One instruction may start (or
1038 // end) multiple scopes. Ignore scopes that are not reachable.
1039 void DwarfDebug::identifyScopeMarkers() {
1040 SmallVector<LexicalScope *, 4> WorkList;
1041 WorkList.push_back(LScopes.getCurrentFunctionScope());
1042 while (!WorkList.empty()) {
1043 LexicalScope *S = WorkList.pop_back_val();
1045 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1046 if (!Children.empty())
1047 WorkList.append(Children.begin(), Children.end());
1049 if (S->isAbstractScope())
1052 for (const InsnRange &R : S->getRanges()) {
1053 assert(R.first && "InsnRange does not have first instruction!");
1054 assert(R.second && "InsnRange does not have second instruction!");
1055 requestLabelBeforeInsn(R.first);
1056 requestLabelAfterInsn(R.second);
1061 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1062 // First known non-DBG_VALUE and non-frame setup location marks
1063 // the beginning of the function body.
1064 for (const auto &MBB : *MF)
1065 for (const auto &MI : MBB)
1066 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1068 // Did the target forget to set the FrameSetup flag for CFI insns?
1069 assert(!MI.isCFIInstruction() &&
1070 "First non-frame-setup instruction is a CFI instruction.");
1071 return MI.getDebugLoc();
1076 // Gather pre-function debug information. Assumes being called immediately
1077 // after the function entry point has been emitted.
1078 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1081 // If there's no debug info for the function we're not going to do anything.
1082 if (!MMI->hasDebugInfo())
1085 auto DI = FunctionDIs.find(MF->getFunction());
1086 if (DI == FunctionDIs.end())
1089 // Grab the lexical scopes for the function, if we don't have any of those
1090 // then we're not going to be able to do anything.
1091 LScopes.initialize(*MF);
1092 if (LScopes.empty())
1095 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1097 // Make sure that each lexical scope will have a begin/end label.
1098 identifyScopeMarkers();
1100 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1101 // belongs to so that we add to the correct per-cu line table in the
1103 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1104 // FnScope->getScopeNode() and DI->second should represent the same function,
1105 // though they may not be the same MDNode due to inline functions merged in
1106 // LTO where the debug info metadata still differs (either due to distinct
1107 // written differences - two versions of a linkonce_odr function
1108 // written/copied into two separate files, or some sub-optimal metadata that
1109 // isn't structurally identical (see: file path/name info from clang, which
1110 // includes the directory of the cpp file being built, even when the file name
1111 // is absolute (such as an <> lookup header)))
1112 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1113 assert(TheCU && "Unable to find compile unit!");
1114 if (Asm->OutStreamer.hasRawTextSupport())
1115 // Use a single line table if we are generating assembly.
1116 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1118 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1120 // Calculate history for local variables.
1121 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1124 // Request labels for the full history.
1125 for (const auto &I : DbgValues) {
1126 const auto &Ranges = I.second;
1130 // The first mention of a function argument gets the CurrentFnBegin
1131 // label, so arguments are visible when breaking at function entry.
1132 DIVariable DIVar = Ranges.front().first->getDebugVariable();
1133 if (DIVar->getTag() == dwarf::DW_TAG_arg_variable &&
1134 getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) {
1135 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin();
1136 if (Ranges.front().first->getDebugExpression()->isBitPiece()) {
1137 // Mark all non-overlapping initial pieces.
1138 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1139 DIExpression Piece = I->first->getDebugExpression();
1140 if (std::all_of(Ranges.begin(), I,
1141 [&](DbgValueHistoryMap::InstrRange Pred) {
1142 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1144 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
1151 for (const auto &Range : Ranges) {
1152 requestLabelBeforeInsn(Range.first);
1154 requestLabelAfterInsn(Range.second);
1158 PrevInstLoc = DebugLoc();
1159 PrevLabel = Asm->getFunctionBegin();
1161 // Record beginning of function.
1162 PrologEndLoc = findPrologueEndLoc(MF);
1163 if (MDLocation *L = PrologEndLoc) {
1164 // We'd like to list the prologue as "not statements" but GDB behaves
1165 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1166 auto *SP = L->getInlinedAtScope()->getSubprogram();
1167 recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT);
1171 // Gather and emit post-function debug information.
1172 void DwarfDebug::endFunction(const MachineFunction *MF) {
1173 assert(CurFn == MF &&
1174 "endFunction should be called with the same function as beginFunction");
1176 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1177 !FunctionDIs.count(MF->getFunction())) {
1178 // If we don't have a lexical scope for this function then there will
1179 // be a hole in the range information. Keep note of this by setting the
1180 // previously used section to nullptr.
1186 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1187 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1189 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1190 auto *SP = cast<MDSubprogram>(FnScope->getScopeNode());
1191 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1193 DenseSet<InlinedVariable> ProcessedVars;
1194 collectVariableInfo(TheCU, SP, ProcessedVars);
1196 // Add the range of this function to the list of ranges for the CU.
1197 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd()));
1199 // Under -gmlt, skip building the subprogram if there are no inlined
1200 // subroutines inside it.
1201 if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly &&
1202 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1203 assert(InfoHolder.getScopeVariables().empty());
1204 assert(DbgValues.empty());
1205 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1206 // by a -gmlt CU. Add a test and remove this assertion.
1207 assert(AbstractVariables.empty());
1208 LabelsBeforeInsn.clear();
1209 LabelsAfterInsn.clear();
1210 PrevLabel = nullptr;
1216 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1218 // Construct abstract scopes.
1219 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1220 auto *SP = cast<MDSubprogram>(AScope->getScopeNode());
1221 // Collect info for variables that were optimized out.
1222 for (DIVariable DV : SP->getVariables()) {
1223 if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second)
1225 ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr),
1227 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1228 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1230 constructAbstractSubprogramScopeDIE(AScope);
1233 TheCU.constructSubprogramScopeDIE(FnScope);
1234 if (auto *SkelCU = TheCU.getSkeleton())
1235 if (!LScopes.getAbstractScopesList().empty())
1236 SkelCU->constructSubprogramScopeDIE(FnScope);
1239 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1240 // DbgVariables except those that are also in AbstractVariables (since they
1241 // can be used cross-function)
1242 InfoHolder.getScopeVariables().clear();
1244 LabelsBeforeInsn.clear();
1245 LabelsAfterInsn.clear();
1246 PrevLabel = nullptr;
1250 // Register a source line with debug info. Returns the unique label that was
1251 // emitted and which provides correspondence to the source line list.
1252 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1257 unsigned Discriminator = 0;
1258 if (auto *Scope = cast_or_null<MDScope>(S)) {
1259 Fn = Scope->getFilename();
1260 Dir = Scope->getDirectory();
1261 if (auto *LBF = dyn_cast<MDLexicalBlockFile>(Scope))
1262 Discriminator = LBF->getDiscriminator();
1264 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1265 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1266 .getOrCreateSourceID(Fn, Dir);
1268 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1272 //===----------------------------------------------------------------------===//
1274 //===----------------------------------------------------------------------===//
1276 // Emit the debug info section.
1277 void DwarfDebug::emitDebugInfo() {
1278 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1279 Holder.emitUnits(/* UseOffsets */ false);
1282 // Emit the abbreviation section.
1283 void DwarfDebug::emitAbbreviations() {
1284 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1286 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1289 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1290 StringRef TableName) {
1291 Accel.FinalizeTable(Asm, TableName);
1292 Asm->OutStreamer.SwitchSection(Section);
1294 // Emit the full data.
1295 Accel.emit(Asm, Section->getBeginSymbol(), this);
1298 // Emit visible names into a hashed accelerator table section.
1299 void DwarfDebug::emitAccelNames() {
1300 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1304 // Emit objective C classes and categories into a hashed accelerator table
1306 void DwarfDebug::emitAccelObjC() {
1307 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1311 // Emit namespace dies into a hashed accelerator table.
1312 void DwarfDebug::emitAccelNamespaces() {
1313 emitAccel(AccelNamespace,
1314 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1318 // Emit type dies into a hashed accelerator table.
1319 void DwarfDebug::emitAccelTypes() {
1320 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1324 // Public name handling.
1325 // The format for the various pubnames:
1327 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1328 // for the DIE that is named.
1330 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1331 // into the CU and the index value is computed according to the type of value
1332 // for the DIE that is named.
1334 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1335 // it's the offset within the debug_info/debug_types dwo section, however, the
1336 // reference in the pubname header doesn't change.
1338 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1339 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1341 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1343 // We could have a specification DIE that has our most of our knowledge,
1344 // look for that now.
1345 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1347 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1348 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1349 Linkage = dwarf::GIEL_EXTERNAL;
1350 } else if (Die->findAttribute(dwarf::DW_AT_external))
1351 Linkage = dwarf::GIEL_EXTERNAL;
1353 switch (Die->getTag()) {
1354 case dwarf::DW_TAG_class_type:
1355 case dwarf::DW_TAG_structure_type:
1356 case dwarf::DW_TAG_union_type:
1357 case dwarf::DW_TAG_enumeration_type:
1358 return dwarf::PubIndexEntryDescriptor(
1359 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1360 ? dwarf::GIEL_STATIC
1361 : dwarf::GIEL_EXTERNAL);
1362 case dwarf::DW_TAG_typedef:
1363 case dwarf::DW_TAG_base_type:
1364 case dwarf::DW_TAG_subrange_type:
1365 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1366 case dwarf::DW_TAG_namespace:
1367 return dwarf::GIEK_TYPE;
1368 case dwarf::DW_TAG_subprogram:
1369 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1370 case dwarf::DW_TAG_variable:
1371 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1372 case dwarf::DW_TAG_enumerator:
1373 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1374 dwarf::GIEL_STATIC);
1376 return dwarf::GIEK_NONE;
1380 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1382 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1383 const MCSection *PSec =
1384 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1385 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1387 emitDebugPubSection(GnuStyle, PSec, "Names",
1388 &DwarfCompileUnit::getGlobalNames);
1391 void DwarfDebug::emitDebugPubSection(
1392 bool GnuStyle, const MCSection *PSec, StringRef Name,
1393 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1394 for (const auto &NU : CUMap) {
1395 DwarfCompileUnit *TheU = NU.second;
1397 const auto &Globals = (TheU->*Accessor)();
1399 if (Globals.empty())
1402 if (auto *Skeleton = TheU->getSkeleton())
1405 // Start the dwarf pubnames section.
1406 Asm->OutStreamer.SwitchSection(PSec);
1409 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1410 MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin");
1411 MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end");
1412 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1414 Asm->OutStreamer.EmitLabel(BeginLabel);
1416 Asm->OutStreamer.AddComment("DWARF Version");
1417 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1419 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1420 Asm->emitSectionOffset(TheU->getLabelBegin());
1422 Asm->OutStreamer.AddComment("Compilation Unit Length");
1423 Asm->EmitInt32(TheU->getLength());
1425 // Emit the pubnames for this compilation unit.
1426 for (const auto &GI : Globals) {
1427 const char *Name = GI.getKeyData();
1428 const DIE *Entity = GI.second;
1430 Asm->OutStreamer.AddComment("DIE offset");
1431 Asm->EmitInt32(Entity->getOffset());
1434 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1435 Asm->OutStreamer.AddComment(
1436 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1437 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1438 Asm->EmitInt8(Desc.toBits());
1441 Asm->OutStreamer.AddComment("External Name");
1442 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1445 Asm->OutStreamer.AddComment("End Mark");
1447 Asm->OutStreamer.EmitLabel(EndLabel);
1451 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1452 const MCSection *PSec =
1453 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1454 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1456 emitDebugPubSection(GnuStyle, PSec, "Types",
1457 &DwarfCompileUnit::getGlobalTypes);
1460 // Emit visible names into a debug str section.
1461 void DwarfDebug::emitDebugStr() {
1462 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1463 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1466 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1467 const DebugLocStream::Entry &Entry) {
1468 auto &&Comments = DebugLocs.getComments(Entry);
1469 auto Comment = Comments.begin();
1470 auto End = Comments.end();
1471 for (uint8_t Byte : DebugLocs.getBytes(Entry))
1472 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1475 static void emitDebugLocValue(const AsmPrinter &AP, const MDBasicType *BT,
1476 ByteStreamer &Streamer,
1477 const DebugLocEntry::Value &Value,
1478 unsigned PieceOffsetInBits) {
1479 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(),
1480 AP.getDwarfDebug()->getDwarfVersion(),
1483 if (Value.isInt()) {
1484 if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed ||
1485 BT->getEncoding() == dwarf::DW_ATE_signed_char))
1486 DwarfExpr.AddSignedConstant(Value.getInt());
1488 DwarfExpr.AddUnsignedConstant(Value.getInt());
1489 } else if (Value.isLocation()) {
1490 MachineLocation Loc = Value.getLoc();
1491 DIExpression Expr = Value.getExpression();
1492 if (!Expr || !Expr->getNumElements())
1494 AP.EmitDwarfRegOp(Streamer, Loc);
1496 // Complex address entry.
1497 if (Loc.getOffset()) {
1498 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1499 DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(),
1502 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1506 // else ... ignore constant fp. There is not any good way to
1507 // to represent them here in dwarf.
1511 void DebugLocEntry::finalize(const AsmPrinter &AP, DebugLocStream &Locs,
1512 const MDBasicType *BT) {
1513 Locs.startEntry(Begin, End);
1514 BufferByteStreamer Streamer = Locs.getStreamer();
1515 const DebugLocEntry::Value &Value = Values[0];
1516 if (Value.isBitPiece()) {
1517 // Emit all pieces that belong to the same variable and range.
1518 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1519 return P.isBitPiece();
1520 }) && "all values are expected to be pieces");
1521 assert(std::is_sorted(Values.begin(), Values.end()) &&
1522 "pieces are expected to be sorted");
1524 unsigned Offset = 0;
1525 for (auto Piece : Values) {
1526 DIExpression Expr = Piece.getExpression();
1527 unsigned PieceOffset = Expr->getBitPieceOffset();
1528 unsigned PieceSize = Expr->getBitPieceSize();
1529 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1530 if (Offset < PieceOffset) {
1531 // The DWARF spec seriously mandates pieces with no locations for gaps.
1532 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(),
1533 AP.getDwarfDebug()->getDwarfVersion(),
1535 Expr.AddOpPiece(PieceOffset-Offset, 0);
1536 Offset += PieceOffset-Offset;
1538 Offset += PieceSize;
1540 emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset);
1543 assert(Values.size() == 1 && "only pieces may have >1 value");
1544 emitDebugLocValue(AP, BT, Streamer, Value, 0);
1548 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) {
1549 Asm->OutStreamer.AddComment("Loc expr size");
1550 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1551 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1552 Asm->EmitLabelDifference(end, begin, 2);
1553 Asm->OutStreamer.EmitLabel(begin);
1555 APByteStreamer Streamer(*Asm);
1556 emitDebugLocEntry(Streamer, Entry);
1558 Asm->OutStreamer.EmitLabel(end);
1561 // Emit locations into the debug loc section.
1562 void DwarfDebug::emitDebugLoc() {
1563 // Start the dwarf loc section.
1564 Asm->OutStreamer.SwitchSection(
1565 Asm->getObjFileLowering().getDwarfLocSection());
1566 unsigned char Size = Asm->getDataLayout().getPointerSize();
1567 for (const auto &List : DebugLocs.getLists()) {
1568 Asm->OutStreamer.EmitLabel(List.Label);
1569 const DwarfCompileUnit *CU = List.CU;
1570 for (const auto &Entry : DebugLocs.getEntries(List)) {
1571 // Set up the range. This range is relative to the entry point of the
1572 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1573 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1574 if (auto *Base = CU->getBaseAddress()) {
1575 Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
1576 Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
1578 Asm->OutStreamer.EmitSymbolValue(Entry.BeginSym, Size);
1579 Asm->OutStreamer.EmitSymbolValue(Entry.EndSym, Size);
1582 emitDebugLocEntryLocation(Entry);
1584 Asm->OutStreamer.EmitIntValue(0, Size);
1585 Asm->OutStreamer.EmitIntValue(0, Size);
1589 void DwarfDebug::emitDebugLocDWO() {
1590 Asm->OutStreamer.SwitchSection(
1591 Asm->getObjFileLowering().getDwarfLocDWOSection());
1592 for (const auto &List : DebugLocs.getLists()) {
1593 Asm->OutStreamer.EmitLabel(List.Label);
1594 for (const auto &Entry : DebugLocs.getEntries(List)) {
1595 // Just always use start_length for now - at least that's one address
1596 // rather than two. We could get fancier and try to, say, reuse an
1597 // address we know we've emitted elsewhere (the start of the function?
1598 // The start of the CU or CU subrange that encloses this range?)
1599 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1600 unsigned idx = AddrPool.getIndex(Entry.BeginSym);
1601 Asm->EmitULEB128(idx);
1602 Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4);
1604 emitDebugLocEntryLocation(Entry);
1606 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1611 const MCSymbol *Start, *End;
1614 // Emit a debug aranges section, containing a CU lookup for any
1615 // address we can tie back to a CU.
1616 void DwarfDebug::emitDebugARanges() {
1617 // Provides a unique id per text section.
1618 MapVector<const MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1620 // Filter labels by section.
1621 for (const SymbolCU &SCU : ArangeLabels) {
1622 if (SCU.Sym->isInSection()) {
1623 // Make a note of this symbol and it's section.
1624 const MCSection *Section = &SCU.Sym->getSection();
1625 if (!Section->getKind().isMetadata())
1626 SectionMap[Section].push_back(SCU);
1628 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1629 // appear in the output. This sucks as we rely on sections to build
1630 // arange spans. We can do it without, but it's icky.
1631 SectionMap[nullptr].push_back(SCU);
1635 // Add terminating symbols for each section.
1636 for (const auto &I : SectionMap) {
1637 const MCSection *Section = I.first;
1638 MCSymbol *Sym = nullptr;
1641 Sym = Asm->OutStreamer.endSection(Section);
1643 // Insert a final terminator.
1644 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1647 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1649 for (auto &I : SectionMap) {
1650 const MCSection *Section = I.first;
1651 SmallVector<SymbolCU, 8> &List = I.second;
1652 if (List.size() < 2)
1655 // If we have no section (e.g. common), just write out
1656 // individual spans for each symbol.
1658 for (const SymbolCU &Cur : List) {
1660 Span.Start = Cur.Sym;
1663 Spans[Cur.CU].push_back(Span);
1668 // Sort the symbols by offset within the section.
1669 std::sort(List.begin(), List.end(),
1670 [&](const SymbolCU &A, const SymbolCU &B) {
1671 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1672 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1674 // Symbols with no order assigned should be placed at the end.
1675 // (e.g. section end labels)
1683 // Build spans between each label.
1684 const MCSymbol *StartSym = List[0].Sym;
1685 for (size_t n = 1, e = List.size(); n < e; n++) {
1686 const SymbolCU &Prev = List[n - 1];
1687 const SymbolCU &Cur = List[n];
1689 // Try and build the longest span we can within the same CU.
1690 if (Cur.CU != Prev.CU) {
1692 Span.Start = StartSym;
1694 Spans[Prev.CU].push_back(Span);
1700 // Start the dwarf aranges section.
1701 Asm->OutStreamer.SwitchSection(
1702 Asm->getObjFileLowering().getDwarfARangesSection());
1704 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1706 // Build a list of CUs used.
1707 std::vector<DwarfCompileUnit *> CUs;
1708 for (const auto &it : Spans) {
1709 DwarfCompileUnit *CU = it.first;
1713 // Sort the CU list (again, to ensure consistent output order).
1714 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1715 return A->getUniqueID() < B->getUniqueID();
1718 // Emit an arange table for each CU we used.
1719 for (DwarfCompileUnit *CU : CUs) {
1720 std::vector<ArangeSpan> &List = Spans[CU];
1722 // Describe the skeleton CU's offset and length, not the dwo file's.
1723 if (auto *Skel = CU->getSkeleton())
1726 // Emit size of content not including length itself.
1727 unsigned ContentSize =
1728 sizeof(int16_t) + // DWARF ARange version number
1729 sizeof(int32_t) + // Offset of CU in the .debug_info section
1730 sizeof(int8_t) + // Pointer Size (in bytes)
1731 sizeof(int8_t); // Segment Size (in bytes)
1733 unsigned TupleSize = PtrSize * 2;
1735 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1737 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1739 ContentSize += Padding;
1740 ContentSize += (List.size() + 1) * TupleSize;
1742 // For each compile unit, write the list of spans it covers.
1743 Asm->OutStreamer.AddComment("Length of ARange Set");
1744 Asm->EmitInt32(ContentSize);
1745 Asm->OutStreamer.AddComment("DWARF Arange version number");
1746 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1747 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1748 Asm->emitSectionOffset(CU->getLabelBegin());
1749 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1750 Asm->EmitInt8(PtrSize);
1751 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1754 Asm->OutStreamer.EmitFill(Padding, 0xff);
1756 for (const ArangeSpan &Span : List) {
1757 Asm->EmitLabelReference(Span.Start, PtrSize);
1759 // Calculate the size as being from the span start to it's end.
1761 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1763 // For symbols without an end marker (e.g. common), we
1764 // write a single arange entry containing just that one symbol.
1765 uint64_t Size = SymSize[Span.Start];
1769 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1773 Asm->OutStreamer.AddComment("ARange terminator");
1774 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1775 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1779 // Emit visible names into a debug ranges section.
1780 void DwarfDebug::emitDebugRanges() {
1781 // Start the dwarf ranges section.
1782 Asm->OutStreamer.SwitchSection(
1783 Asm->getObjFileLowering().getDwarfRangesSection());
1785 // Size for our labels.
1786 unsigned char Size = Asm->getDataLayout().getPointerSize();
1788 // Grab the specific ranges for the compile units in the module.
1789 for (const auto &I : CUMap) {
1790 DwarfCompileUnit *TheCU = I.second;
1792 if (auto *Skel = TheCU->getSkeleton())
1795 // Iterate over the misc ranges for the compile units in the module.
1796 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1797 // Emit our symbol so we can find the beginning of the range.
1798 Asm->OutStreamer.EmitLabel(List.getSym());
1800 for (const RangeSpan &Range : List.getRanges()) {
1801 const MCSymbol *Begin = Range.getStart();
1802 const MCSymbol *End = Range.getEnd();
1803 assert(Begin && "Range without a begin symbol?");
1804 assert(End && "Range without an end symbol?");
1805 if (auto *Base = TheCU->getBaseAddress()) {
1806 Asm->EmitLabelDifference(Begin, Base, Size);
1807 Asm->EmitLabelDifference(End, Base, Size);
1809 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1810 Asm->OutStreamer.EmitSymbolValue(End, Size);
1814 // And terminate the list with two 0 values.
1815 Asm->OutStreamer.EmitIntValue(0, Size);
1816 Asm->OutStreamer.EmitIntValue(0, Size);
1821 // DWARF5 Experimental Separate Dwarf emitters.
1823 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1824 std::unique_ptr<DwarfUnit> NewU) {
1825 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1826 U.getCUNode()->getSplitDebugFilename());
1828 if (!CompilationDir.empty())
1829 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1831 addGnuPubAttributes(*NewU, Die);
1833 SkeletonHolder.addUnit(std::move(NewU));
1836 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1837 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1838 // DW_AT_addr_base, DW_AT_ranges_base.
1839 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1841 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1842 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1843 DwarfCompileUnit &NewCU = *OwnedUnit;
1844 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1846 NewCU.initStmtList();
1848 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1853 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1854 // compile units that would normally be in debug_info.
1855 void DwarfDebug::emitDebugInfoDWO() {
1856 assert(useSplitDwarf() && "No split dwarf debug info?");
1857 // Don't emit relocations into the dwo file.
1858 InfoHolder.emitUnits(/* UseOffsets */ true);
1861 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1862 // abbreviations for the .debug_info.dwo section.
1863 void DwarfDebug::emitDebugAbbrevDWO() {
1864 assert(useSplitDwarf() && "No split dwarf?");
1865 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1868 void DwarfDebug::emitDebugLineDWO() {
1869 assert(useSplitDwarf() && "No split dwarf?");
1870 Asm->OutStreamer.SwitchSection(
1871 Asm->getObjFileLowering().getDwarfLineDWOSection());
1872 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
1875 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1876 // string section and is identical in format to traditional .debug_str
1878 void DwarfDebug::emitDebugStrDWO() {
1879 assert(useSplitDwarf() && "No split dwarf?");
1880 const MCSection *OffSec =
1881 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1882 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1886 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1887 if (!useSplitDwarf())
1890 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory());
1891 return &SplitTypeUnitFileTable;
1894 static uint64_t makeTypeSignature(StringRef Identifier) {
1896 Hash.update(Identifier);
1897 // ... take the least significant 8 bytes and return those. Our MD5
1898 // implementation always returns its results in little endian, swap bytes
1900 MD5::MD5Result Result;
1902 return support::endian::read64le(Result + 8);
1905 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1906 StringRef Identifier, DIE &RefDie,
1907 const MDCompositeType *CTy) {
1908 // Fast path if we're building some type units and one has already used the
1909 // address pool we know we're going to throw away all this work anyway, so
1910 // don't bother building dependent types.
1911 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1914 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1916 CU.addDIETypeSignature(RefDie, *TU);
1920 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1921 AddrPool.resetUsedFlag();
1923 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1924 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1925 this, &InfoHolder, getDwoLineTable(CU));
1926 DwarfTypeUnit &NewTU = *OwnedUnit;
1927 DIE &UnitDie = NewTU.getUnitDie();
1929 TypeUnitsUnderConstruction.push_back(
1930 std::make_pair(std::move(OwnedUnit), CTy));
1932 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1935 uint64_t Signature = makeTypeSignature(Identifier);
1936 NewTU.setTypeSignature(Signature);
1938 if (useSplitDwarf())
1939 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
1941 CU.applyStmtList(UnitDie);
1943 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
1946 NewTU.setType(NewTU.createTypeDIE(CTy));
1949 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
1950 TypeUnitsUnderConstruction.clear();
1952 // Types referencing entries in the address table cannot be placed in type
1954 if (AddrPool.hasBeenUsed()) {
1956 // Remove all the types built while building this type.
1957 // This is pessimistic as some of these types might not be dependent on
1958 // the type that used an address.
1959 for (const auto &TU : TypeUnitsToAdd)
1960 DwarfTypeUnits.erase(TU.second);
1962 // Construct this type in the CU directly.
1963 // This is inefficient because all the dependent types will be rebuilt
1964 // from scratch, including building them in type units, discovering that
1965 // they depend on addresses, throwing them out and rebuilding them.
1966 CU.constructTypeDIE(RefDie, cast<MDCompositeType>(CTy));
1970 // If the type wasn't dependent on fission addresses, finish adding the type
1971 // and all its dependent types.
1972 for (auto &TU : TypeUnitsToAdd)
1973 InfoHolder.addUnit(std::move(TU.first));
1975 CU.addDIETypeSignature(RefDie, NewTU);
1978 // Accelerator table mutators - add each name along with its companion
1979 // DIE to the proper table while ensuring that the name that we're going
1980 // to reference is in the string table. We do this since the names we
1981 // add may not only be identical to the names in the DIE.
1982 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
1983 if (!useDwarfAccelTables())
1985 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1989 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
1990 if (!useDwarfAccelTables())
1992 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
1996 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
1997 if (!useDwarfAccelTables())
1999 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2003 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2004 if (!useDwarfAccelTables())
2006 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),