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/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 //===----------------------------------------------------------------------===//
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
151 uint16_t tag = Ty.getTag();
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
173 InfoHolder(A, *this, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
204 HasSplitDwarf = SplitDwarf == Enable;
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
209 HasDwarfPubSections = DwarfPubSections == Enable;
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
224 DwarfDebug::~DwarfDebug() { }
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
247 return Name.find(") ") != StringRef::npos;
250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
267 // Helper for sorting sections into a stable output order.
268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
281 addAccelName(SP.getName(), Die);
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
288 // If this is an Objective-C selector name add it to the ObjC accelerator
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 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.getLanguage());
388 NewCU.addString(Die, dwarf::DW_AT_name, FN);
390 if (!useSplitDwarf()) {
391 NewCU.initStmtList(DwarfLineSectionSym);
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(),
414 DwarfInfoDWOSectionSym);
416 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
417 DwarfInfoSectionSym);
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(N);
427 assert(Module.Verify());
428 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
429 D->addChild(TheCU.constructImportedEntityDIE(Module));
432 // Emit all Dwarf sections that should come prior to the content. Create
433 // global DIEs and emit initial debug info sections. This is invoked by
434 // the target AsmPrinter.
435 void DwarfDebug::beginModule() {
436 if (DisableDebugInfoPrinting)
439 const Module *M = MMI->getModule();
441 FunctionDIs = makeSubprogramMap(*M);
443 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
446 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
448 // Emit initial sections so we can reference labels later.
451 SingleCU = CU_Nodes->getNumOperands() == 1;
453 for (MDNode *N : CU_Nodes->operands()) {
454 DICompileUnit CUNode(N);
455 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
456 DIArray ImportedEntities = CUNode.getImportedEntities();
457 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
458 ScopesWithImportedEntities.push_back(std::make_pair(
459 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
460 ImportedEntities.getElement(i)));
461 std::sort(ScopesWithImportedEntities.begin(),
462 ScopesWithImportedEntities.end(), less_first());
463 DIArray GVs = CUNode.getGlobalVariables();
464 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
465 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
466 DIArray SPs = CUNode.getSubprograms();
467 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
468 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
469 DIArray EnumTypes = CUNode.getEnumTypes();
470 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
471 DIType Ty(EnumTypes.getElement(i));
472 // The enum types array by design contains pointers to
473 // MDNodes rather than DIRefs. Unique them here.
474 DIType UniqueTy(resolve(Ty.getRef()));
475 CU.getOrCreateTypeDIE(UniqueTy);
477 DIArray RetainedTypes = CUNode.getRetainedTypes();
478 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
479 DIType Ty(RetainedTypes.getElement(i));
480 // The retained types array by design contains pointers to
481 // MDNodes rather than DIRefs. Unique them here.
482 DIType UniqueTy(resolve(Ty.getRef()));
483 CU.getOrCreateTypeDIE(UniqueTy);
485 // Emit imported_modules last so that the relevant context is already
487 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
488 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
491 // Tell MMI that we have debug info.
492 MMI->setDebugInfoAvailability(true);
494 // Prime section data.
495 SectionMap[Asm->getObjFileLowering().getTextSection()];
498 void DwarfDebug::finishVariableDefinitions() {
499 for (const auto &Var : ConcreteVariables) {
500 DIE *VariableDie = Var->getDIE();
502 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
503 // in the ConcreteVariables list, rather than looking it up again here.
504 // DIE::getUnit isn't simple - it walks parent pointers, etc.
505 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
507 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
508 if (AbsVar && AbsVar->getDIE()) {
509 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
512 Unit->applyVariableAttributes(*Var, *VariableDie);
516 void DwarfDebug::finishSubprogramDefinitions() {
517 for (const auto &P : SPMap)
518 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
519 CU.finishSubprogramDefinition(DISubprogram(P.first));
524 // Collect info for variables that were optimized out.
525 void DwarfDebug::collectDeadVariables() {
526 const Module *M = MMI->getModule();
528 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
529 for (MDNode *N : CU_Nodes->operands()) {
530 DICompileUnit TheCU(N);
531 // Construct subprogram DIE and add variables DIEs.
532 DwarfCompileUnit *SPCU =
533 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
534 assert(SPCU && "Unable to find Compile Unit!");
535 DIArray Subprograms = TheCU.getSubprograms();
536 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
537 DISubprogram SP(Subprograms.getElement(i));
538 if (ProcessedSPNodes.count(SP) != 0)
540 SPCU->collectDeadVariables(SP);
546 void DwarfDebug::finalizeModuleInfo() {
547 finishSubprogramDefinitions();
549 finishVariableDefinitions();
551 // Collect info for variables that were optimized out.
552 collectDeadVariables();
554 // Handle anything that needs to be done on a per-unit basis after
555 // all other generation.
556 for (const auto &P : CUMap) {
557 auto &TheCU = *P.second;
558 // Emit DW_AT_containing_type attribute to connect types with their
559 // vtable holding type.
560 TheCU.constructContainingTypeDIEs();
562 // Add CU specific attributes if we need to add any.
563 // If we're splitting the dwarf out now that we've got the entire
564 // CU then add the dwo id to it.
565 auto *SkCU = TheCU.getSkeleton();
566 if (useSplitDwarf()) {
567 // Emit a unique identifier for this CU.
568 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
569 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
570 dwarf::DW_FORM_data8, ID);
571 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
572 dwarf::DW_FORM_data8, ID);
574 // We don't keep track of which addresses are used in which CU so this
575 // is a bit pessimistic under LTO.
576 if (!AddrPool.isEmpty())
577 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
578 DwarfAddrSectionSym, DwarfAddrSectionSym);
579 if (!SkCU->getRangeLists().empty())
580 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
581 DwarfDebugRangeSectionSym,
582 DwarfDebugRangeSectionSym);
585 // If we have code split among multiple sections or non-contiguous
586 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
587 // remain in the .o file, otherwise add a DW_AT_low_pc.
588 // FIXME: We should use ranges allow reordering of code ala
589 // .subsections_via_symbols in mach-o. This would mean turning on
590 // ranges for all subprogram DIEs for mach-o.
591 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
592 if (unsigned NumRanges = TheCU.getRanges().size()) {
594 // A DW_AT_low_pc attribute may also be specified in combination with
595 // DW_AT_ranges to specify the default base address for use in
596 // location lists (see Section 2.6.2) and range lists (see Section
598 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
600 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
601 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
605 // Compute DIE offsets and sizes.
606 InfoHolder.computeSizeAndOffsets();
608 SkeletonHolder.computeSizeAndOffsets();
611 void DwarfDebug::endSections() {
612 // Filter labels by section.
613 for (const SymbolCU &SCU : ArangeLabels) {
614 if (SCU.Sym->isInSection()) {
615 // Make a note of this symbol and it's section.
616 const MCSection *Section = &SCU.Sym->getSection();
617 if (!Section->getKind().isMetadata())
618 SectionMap[Section].push_back(SCU);
620 // Some symbols (e.g. common/bss on mach-o) can have no section but still
621 // appear in the output. This sucks as we rely on sections to build
622 // arange spans. We can do it without, but it's icky.
623 SectionMap[nullptr].push_back(SCU);
627 // Build a list of sections used.
628 std::vector<const MCSection *> Sections;
629 for (const auto &it : SectionMap) {
630 const MCSection *Section = it.first;
631 Sections.push_back(Section);
634 // Sort the sections into order.
635 // This is only done to ensure consistent output order across different runs.
636 std::sort(Sections.begin(), Sections.end(), SectionSort);
638 // Add terminating symbols for each section.
639 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
640 const MCSection *Section = Sections[ID];
641 MCSymbol *Sym = nullptr;
644 // We can't call MCSection::getLabelEndName, as it's only safe to do so
645 // if we know the section name up-front. For user-created sections, the
646 // resulting label may not be valid to use as a label. (section names can
647 // use a greater set of characters on some systems)
648 Sym = Asm->GetTempSymbol("debug_end", ID);
649 Asm->OutStreamer.SwitchSection(Section);
650 Asm->OutStreamer.EmitLabel(Sym);
653 // Insert a final terminator.
654 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
658 // Emit all Dwarf sections that should come after the content.
659 void DwarfDebug::endModule() {
660 assert(CurFn == nullptr);
661 assert(CurMI == nullptr);
663 // If we aren't actually generating debug info (check beginModule -
664 // conditionalized on !DisableDebugInfoPrinting and the presence of the
665 // llvm.dbg.cu metadata node)
666 if (!DwarfInfoSectionSym)
669 // End any existing sections.
670 // TODO: Does this need to happen?
673 // Finalize the debug info for the module.
674 finalizeModuleInfo();
678 // Emit all the DIEs into a debug info section.
681 // Corresponding abbreviations into a abbrev section.
684 // Emit info into a debug aranges section.
685 if (GenerateARangeSection)
688 // Emit info into a debug ranges section.
691 if (useSplitDwarf()) {
694 emitDebugAbbrevDWO();
697 // Emit DWO addresses.
698 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
700 // Emit info into a debug loc section.
703 // Emit info into the dwarf accelerator table sections.
704 if (useDwarfAccelTables()) {
707 emitAccelNamespaces();
711 // Emit the pubnames and pubtypes sections if requested.
712 if (HasDwarfPubSections) {
713 emitDebugPubNames(GenerateGnuPubSections);
714 emitDebugPubTypes(GenerateGnuPubSections);
719 AbstractVariables.clear();
722 // Find abstract variable, if any, associated with Var.
723 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
724 DIVariable &Cleansed) {
725 LLVMContext &Ctx = DV->getContext();
726 // More then one inlined variable corresponds to one abstract variable.
727 // FIXME: This duplication of variables when inlining should probably be
728 // removed. It's done to allow each DIVariable to describe its location
729 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
730 // make it accurate then remove this duplication/cleansing stuff.
731 Cleansed = cleanseInlinedVariable(DV, Ctx);
732 auto I = AbstractVariables.find(Cleansed);
733 if (I != AbstractVariables.end())
734 return I->second.get();
738 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
740 return getExistingAbstractVariable(DV, Cleansed);
743 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
744 LexicalScope *Scope) {
745 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
746 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
747 AbstractVariables[Var] = std::move(AbsDbgVariable);
750 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
751 const MDNode *ScopeNode) {
752 DIVariable Cleansed = DV;
753 if (getExistingAbstractVariable(DV, Cleansed))
756 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
760 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
761 const MDNode *ScopeNode) {
762 DIVariable Cleansed = DV;
763 if (getExistingAbstractVariable(DV, Cleansed))
766 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
767 createAbstractVariable(Cleansed, Scope);
770 // Collect variable information from side table maintained by MMI.
771 void DwarfDebug::collectVariableInfoFromMMITable(
772 SmallPtrSetImpl<const MDNode *> &Processed) {
773 for (const auto &VI : MMI->getVariableDbgInfo()) {
776 Processed.insert(VI.Var);
777 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
779 // If variable scope is not found then skip this variable.
783 DIVariable DV(VI.Var);
784 DIExpression Expr(VI.Expr);
785 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
786 auto RegVar = make_unique<DbgVariable>(DV, Expr, this, VI.Slot);
787 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
788 ConcreteVariables.push_back(std::move(RegVar));
792 // Get .debug_loc entry for the instruction range starting at MI.
793 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
794 const MDNode *Expr = MI->getDebugExpression();
795 const MDNode *Var = MI->getDebugVariable();
797 assert(MI->getNumOperands() == 4);
798 if (MI->getOperand(0).isReg()) {
799 MachineLocation MLoc;
800 // If the second operand is an immediate, this is a
801 // register-indirect address.
802 if (!MI->getOperand(1).isImm())
803 MLoc.set(MI->getOperand(0).getReg());
805 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
806 return DebugLocEntry::Value(Var, Expr, MLoc);
808 if (MI->getOperand(0).isImm())
809 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
810 if (MI->getOperand(0).isFPImm())
811 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
812 if (MI->getOperand(0).isCImm())
813 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
815 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
818 /// Determine whether two variable pieces overlap.
819 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
820 if (!P1.isBitPiece() || !P2.isBitPiece())
822 unsigned l1 = P1.getBitPieceOffset();
823 unsigned l2 = P2.getBitPieceOffset();
824 unsigned r1 = l1 + P1.getBitPieceSize();
825 unsigned r2 = l2 + P2.getBitPieceSize();
826 // True where [l1,r1[ and [r1,r2[ overlap.
827 return (l1 < r2) && (l2 < r1);
830 /// Build the location list for all DBG_VALUEs in the function that
831 /// describe the same variable. If the ranges of several independent
832 /// pieces of the same variable overlap partially, split them up and
833 /// combine the ranges. The resulting DebugLocEntries are will have
834 /// strict monotonically increasing begin addresses and will never
839 // Ranges History [var, loc, piece ofs size]
840 // 0 | [x, (reg0, piece 0, 32)]
841 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
843 // 3 | [clobber reg0]
844 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
848 // [0-1] [x, (reg0, piece 0, 32)]
849 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
850 // [3-4] [x, (reg1, piece 32, 32)]
851 // [4- ] [x, (mem, piece 0, 64)]
853 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
854 const DbgValueHistoryMap::InstrRanges &Ranges) {
855 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
857 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
858 const MachineInstr *Begin = I->first;
859 const MachineInstr *End = I->second;
860 assert(Begin->isDebugValue() && "Invalid History entry");
862 // Check if a variable is inaccessible in this range.
863 if (Begin->getNumOperands() > 1 &&
864 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
869 // If this piece overlaps with any open ranges, truncate them.
870 DIExpression DIExpr = Begin->getDebugExpression();
871 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
872 [&](DebugLocEntry::Value R) {
873 return piecesOverlap(DIExpr, R.getExpression());
875 OpenRanges.erase(Last, OpenRanges.end());
877 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
878 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
880 const MCSymbol *EndLabel;
882 EndLabel = getLabelAfterInsn(End);
883 else if (std::next(I) == Ranges.end())
884 EndLabel = FunctionEndSym;
886 EndLabel = getLabelBeforeInsn(std::next(I)->first);
887 assert(EndLabel && "Forgot label after instruction ending a range!");
889 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
891 auto Value = getDebugLocValue(Begin);
892 DebugLocEntry Loc(StartLabel, EndLabel, Value);
893 bool couldMerge = false;
895 // If this is a piece, it may belong to the current DebugLocEntry.
896 if (DIExpr.isBitPiece()) {
897 // Add this value to the list of open ranges.
898 OpenRanges.push_back(Value);
900 // Attempt to add the piece to the last entry.
901 if (!DebugLoc.empty())
902 if (DebugLoc.back().MergeValues(Loc))
907 // Need to add a new DebugLocEntry. Add all values from still
908 // valid non-overlapping pieces.
909 if (OpenRanges.size())
910 Loc.addValues(OpenRanges);
912 DebugLoc.push_back(std::move(Loc));
915 // Attempt to coalesce the ranges of two otherwise identical
917 auto CurEntry = DebugLoc.rbegin();
918 auto PrevEntry = std::next(CurEntry);
919 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
923 dbgs() << CurEntry->getValues().size() << " Values:\n";
924 for (auto Value : CurEntry->getValues()) {
925 Value.getVariable()->dump();
926 Value.getExpression()->dump();
934 // Find variables for each lexical scope.
936 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
937 SmallPtrSetImpl<const MDNode *> &Processed) {
938 // Grab the variable info that was squirreled away in the MMI side-table.
939 collectVariableInfoFromMMITable(Processed);
941 for (const auto &I : DbgValues) {
942 DIVariable DV(I.first);
943 if (Processed.count(DV))
946 // Instruction ranges, specifying where DV is accessible.
947 const auto &Ranges = I.second;
951 LexicalScope *Scope = nullptr;
952 if (MDNode *IA = DV.getInlinedAt())
953 Scope = LScopes.findInlinedScope(DV.getContext(), IA);
955 Scope = LScopes.findLexicalScope(DV.getContext());
956 // If variable scope is not found then skip this variable.
960 Processed.insert(DV);
961 const MachineInstr *MInsn = Ranges.front().first;
962 assert(MInsn->isDebugValue() && "History must begin with debug value");
963 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
964 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
965 DbgVariable *RegVar = ConcreteVariables.back().get();
966 InfoHolder.addScopeVariable(Scope, RegVar);
968 // Check if the first DBG_VALUE is valid for the rest of the function.
969 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
972 // Handle multiple DBG_VALUE instructions describing one variable.
973 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
975 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
976 DebugLocList &LocList = DotDebugLocEntries.back();
979 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
981 // Build the location list for this variable.
982 buildLocationList(LocList.List, Ranges);
985 // Collect info for variables that were optimized out.
986 DIArray Variables = SP.getVariables();
987 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
988 DIVariable DV(Variables.getElement(i));
989 assert(DV.isVariable());
990 if (!Processed.insert(DV).second)
992 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
993 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
995 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
996 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1001 // Return Label preceding the instruction.
1002 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1003 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1004 assert(Label && "Didn't insert label before instruction");
1008 // Return Label immediately following the instruction.
1009 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1010 return LabelsAfterInsn.lookup(MI);
1013 // Process beginning of an instruction.
1014 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1015 assert(CurMI == nullptr);
1017 // Check if source location changes, but ignore DBG_VALUE locations.
1018 if (!MI->isDebugValue()) {
1019 DebugLoc DL = MI->getDebugLoc();
1020 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1023 if (DL == PrologEndLoc) {
1024 Flags |= DWARF2_FLAG_PROLOGUE_END;
1025 PrologEndLoc = DebugLoc();
1026 Flags |= DWARF2_FLAG_IS_STMT;
1029 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
1030 Flags |= DWARF2_FLAG_IS_STMT;
1032 if (!DL.isUnknown()) {
1033 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1034 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1036 recordSourceLine(0, 0, nullptr, 0);
1040 // Insert labels where requested.
1041 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1042 LabelsBeforeInsn.find(MI);
1045 if (I == LabelsBeforeInsn.end())
1048 // Label already assigned.
1053 PrevLabel = MMI->getContext().CreateTempSymbol();
1054 Asm->OutStreamer.EmitLabel(PrevLabel);
1056 I->second = PrevLabel;
1059 // Process end of an instruction.
1060 void DwarfDebug::endInstruction() {
1061 assert(CurMI != nullptr);
1062 // Don't create a new label after DBG_VALUE instructions.
1063 // They don't generate code.
1064 if (!CurMI->isDebugValue())
1065 PrevLabel = nullptr;
1067 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1068 LabelsAfterInsn.find(CurMI);
1072 if (I == LabelsAfterInsn.end())
1075 // Label already assigned.
1079 // We need a label after this instruction.
1081 PrevLabel = MMI->getContext().CreateTempSymbol();
1082 Asm->OutStreamer.EmitLabel(PrevLabel);
1084 I->second = PrevLabel;
1087 // Each LexicalScope has first instruction and last instruction to mark
1088 // beginning and end of a scope respectively. Create an inverse map that list
1089 // scopes starts (and ends) with an instruction. One instruction may start (or
1090 // end) multiple scopes. Ignore scopes that are not reachable.
1091 void DwarfDebug::identifyScopeMarkers() {
1092 SmallVector<LexicalScope *, 4> WorkList;
1093 WorkList.push_back(LScopes.getCurrentFunctionScope());
1094 while (!WorkList.empty()) {
1095 LexicalScope *S = WorkList.pop_back_val();
1097 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1098 if (!Children.empty())
1099 WorkList.append(Children.begin(), Children.end());
1101 if (S->isAbstractScope())
1104 for (const InsnRange &R : S->getRanges()) {
1105 assert(R.first && "InsnRange does not have first instruction!");
1106 assert(R.second && "InsnRange does not have second instruction!");
1107 requestLabelBeforeInsn(R.first);
1108 requestLabelAfterInsn(R.second);
1113 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1114 // First known non-DBG_VALUE and non-frame setup location marks
1115 // the beginning of the function body.
1116 for (const auto &MBB : *MF)
1117 for (const auto &MI : MBB)
1118 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1119 !MI.getDebugLoc().isUnknown()) {
1120 // Did the target forget to set the FrameSetup flag for CFI insns?
1121 assert(!MI.isCFIInstruction() &&
1122 "First non-frame-setup instruction is a CFI instruction.");
1123 return MI.getDebugLoc();
1128 // Gather pre-function debug information. Assumes being called immediately
1129 // after the function entry point has been emitted.
1130 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1133 // If there's no debug info for the function we're not going to do anything.
1134 if (!MMI->hasDebugInfo())
1137 auto DI = FunctionDIs.find(MF->getFunction());
1138 if (DI == FunctionDIs.end())
1141 // Grab the lexical scopes for the function, if we don't have any of those
1142 // then we're not going to be able to do anything.
1143 LScopes.initialize(*MF);
1144 if (LScopes.empty())
1147 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1149 // Make sure that each lexical scope will have a begin/end label.
1150 identifyScopeMarkers();
1152 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1153 // belongs to so that we add to the correct per-cu line table in the
1155 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1156 // FnScope->getScopeNode() and DI->second should represent the same function,
1157 // though they may not be the same MDNode due to inline functions merged in
1158 // LTO where the debug info metadata still differs (either due to distinct
1159 // written differences - two versions of a linkonce_odr function
1160 // written/copied into two separate files, or some sub-optimal metadata that
1161 // isn't structurally identical (see: file path/name info from clang, which
1162 // includes the directory of the cpp file being built, even when the file name
1163 // is absolute (such as an <> lookup header)))
1164 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1165 assert(TheCU && "Unable to find compile unit!");
1166 if (Asm->OutStreamer.hasRawTextSupport())
1167 // Use a single line table if we are generating assembly.
1168 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1170 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1172 // Emit a label for the function so that we have a beginning address.
1173 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1174 // Assumes in correct section after the entry point.
1175 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1177 // Calculate history for local variables.
1178 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1181 // Request labels for the full history.
1182 for (const auto &I : DbgValues) {
1183 const auto &Ranges = I.second;
1187 // The first mention of a function argument gets the FunctionBeginSym
1188 // label, so arguments are visible when breaking at function entry.
1189 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1190 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1191 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1192 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1193 if (Ranges.front().first->getDebugExpression().isBitPiece()) {
1194 // Mark all non-overlapping initial pieces.
1195 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1196 DIExpression Piece = I->first->getDebugExpression();
1197 if (std::all_of(Ranges.begin(), I,
1198 [&](DbgValueHistoryMap::InstrRange Pred) {
1199 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1201 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1208 for (const auto &Range : Ranges) {
1209 requestLabelBeforeInsn(Range.first);
1211 requestLabelAfterInsn(Range.second);
1215 PrevInstLoc = DebugLoc();
1216 PrevLabel = FunctionBeginSym;
1218 // Record beginning of function.
1219 PrologEndLoc = findPrologueEndLoc(MF);
1220 if (!PrologEndLoc.isUnknown()) {
1221 DebugLoc FnStartDL =
1222 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1224 // We'd like to list the prologue as "not statements" but GDB behaves
1225 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1226 recordSourceLine(FnStartDL.getLine(), FnStartDL.getCol(),
1227 FnStartDL.getScope(MF->getFunction()->getContext()),
1228 DWARF2_FLAG_IS_STMT);
1232 // Gather and emit post-function debug information.
1233 void DwarfDebug::endFunction(const MachineFunction *MF) {
1234 assert(CurFn == MF &&
1235 "endFunction should be called with the same function as beginFunction");
1237 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1238 !FunctionDIs.count(MF->getFunction())) {
1239 // If we don't have a lexical scope for this function then there will
1240 // be a hole in the range information. Keep note of this by setting the
1241 // previously used section to nullptr.
1247 // Define end label for subprogram.
1248 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1249 // Assumes in correct section after the entry point.
1250 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1252 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1253 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1255 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1256 DISubprogram SP(FnScope->getScopeNode());
1257 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1259 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1260 collectVariableInfo(TheCU, SP, ProcessedVars);
1262 // Add the range of this function to the list of ranges for the CU.
1263 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1265 // Under -gmlt, skip building the subprogram if there are no inlined
1266 // subroutines inside it.
1267 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1268 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1269 assert(InfoHolder.getScopeVariables().empty());
1270 assert(DbgValues.empty());
1271 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1272 // by a -gmlt CU. Add a test and remove this assertion.
1273 assert(AbstractVariables.empty());
1274 LabelsBeforeInsn.clear();
1275 LabelsAfterInsn.clear();
1276 PrevLabel = nullptr;
1282 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1284 // Construct abstract scopes.
1285 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1286 DISubprogram SP(AScope->getScopeNode());
1287 assert(SP.isSubprogram());
1288 // Collect info for variables that were optimized out.
1289 DIArray Variables = SP.getVariables();
1290 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1291 DIVariable DV(Variables.getElement(i));
1292 assert(DV && DV.isVariable());
1293 if (!ProcessedVars.insert(DV).second)
1295 ensureAbstractVariableIsCreated(DV, DV.getContext());
1296 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1297 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1299 constructAbstractSubprogramScopeDIE(AScope);
1302 TheCU.constructSubprogramScopeDIE(FnScope);
1303 if (auto *SkelCU = TheCU.getSkeleton())
1304 if (!LScopes.getAbstractScopesList().empty())
1305 SkelCU->constructSubprogramScopeDIE(FnScope);
1308 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1309 // DbgVariables except those that are also in AbstractVariables (since they
1310 // can be used cross-function)
1311 InfoHolder.getScopeVariables().clear();
1313 LabelsBeforeInsn.clear();
1314 LabelsAfterInsn.clear();
1315 PrevLabel = nullptr;
1319 // Register a source line with debug info. Returns the unique label that was
1320 // emitted and which provides correspondence to the source line list.
1321 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1326 unsigned Discriminator = 0;
1327 if (DIScope Scope = DIScope(S)) {
1328 assert(Scope.isScope());
1329 Fn = Scope.getFilename();
1330 Dir = Scope.getDirectory();
1331 if (Scope.isLexicalBlockFile())
1332 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1334 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1335 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1336 .getOrCreateSourceID(Fn, Dir);
1338 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1342 //===----------------------------------------------------------------------===//
1344 //===----------------------------------------------------------------------===//
1346 // Emit initial Dwarf sections with a label at the start of each one.
1347 void DwarfDebug::emitSectionLabels() {
1348 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1350 // Dwarf sections base addresses.
1351 DwarfInfoSectionSym =
1352 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1353 if (useSplitDwarf()) {
1354 DwarfInfoDWOSectionSym =
1355 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1356 DwarfTypesDWOSectionSym =
1357 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1359 DwarfAbbrevSectionSym =
1360 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1361 if (useSplitDwarf())
1362 DwarfAbbrevDWOSectionSym = emitSectionSym(
1363 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1364 if (GenerateARangeSection)
1365 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1367 DwarfLineSectionSym =
1368 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1369 if (GenerateGnuPubSections) {
1370 DwarfGnuPubNamesSectionSym =
1371 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1372 DwarfGnuPubTypesSectionSym =
1373 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1374 } else if (HasDwarfPubSections) {
1375 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1376 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1379 DwarfStrSectionSym =
1380 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1381 if (useSplitDwarf()) {
1382 DwarfStrDWOSectionSym =
1383 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1384 DwarfAddrSectionSym =
1385 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1386 DwarfDebugLocSectionSym =
1387 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1389 DwarfDebugLocSectionSym =
1390 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1391 DwarfDebugRangeSectionSym =
1392 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1395 // Recursively emits a debug information entry.
1396 void DwarfDebug::emitDIE(DIE &Die) {
1397 // Get the abbreviation for this DIE.
1398 const DIEAbbrev &Abbrev = Die.getAbbrev();
1400 // Emit the code (index) for the abbreviation.
1401 if (Asm->isVerbose())
1402 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1403 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1404 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1405 dwarf::TagString(Abbrev.getTag()));
1406 Asm->EmitULEB128(Abbrev.getNumber());
1408 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1409 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1411 // Emit the DIE attribute values.
1412 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1413 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1414 dwarf::Form Form = AbbrevData[i].getForm();
1415 assert(Form && "Too many attributes for DIE (check abbreviation)");
1417 if (Asm->isVerbose()) {
1418 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1419 if (Attr == dwarf::DW_AT_accessibility)
1420 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1421 cast<DIEInteger>(Values[i])->getValue()));
1424 // Emit an attribute using the defined form.
1425 Values[i]->EmitValue(Asm, Form);
1428 // Emit the DIE children if any.
1429 if (Abbrev.hasChildren()) {
1430 for (auto &Child : Die.getChildren())
1433 Asm->OutStreamer.AddComment("End Of Children Mark");
1438 // Emit the debug info section.
1439 void DwarfDebug::emitDebugInfo() {
1440 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1442 Holder.emitUnits(DwarfAbbrevSectionSym);
1445 // Emit the abbreviation section.
1446 void DwarfDebug::emitAbbreviations() {
1447 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1449 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1452 // Emit the last address of the section and the end of the line matrix.
1453 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1454 // Define last address of section.
1455 Asm->OutStreamer.AddComment("Extended Op");
1458 Asm->OutStreamer.AddComment("Op size");
1459 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1460 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1461 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1463 Asm->OutStreamer.AddComment("Section end label");
1465 Asm->OutStreamer.EmitSymbolValue(
1466 Asm->GetTempSymbol("section_end", SectionEnd),
1467 Asm->getDataLayout().getPointerSize());
1469 // Mark end of matrix.
1470 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1476 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1477 StringRef TableName, StringRef SymName) {
1478 Accel.FinalizeTable(Asm, TableName);
1479 Asm->OutStreamer.SwitchSection(Section);
1480 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1481 Asm->OutStreamer.EmitLabel(SectionBegin);
1483 // Emit the full data.
1484 Accel.Emit(Asm, SectionBegin, this, DwarfStrSectionSym);
1487 // Emit visible names into a hashed accelerator table section.
1488 void DwarfDebug::emitAccelNames() {
1489 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1490 "Names", "names_begin");
1493 // Emit objective C classes and categories into a hashed accelerator table
1495 void DwarfDebug::emitAccelObjC() {
1496 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1497 "ObjC", "objc_begin");
1500 // Emit namespace dies into a hashed accelerator table.
1501 void DwarfDebug::emitAccelNamespaces() {
1502 emitAccel(AccelNamespace,
1503 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1504 "namespac", "namespac_begin");
1507 // Emit type dies into a hashed accelerator table.
1508 void DwarfDebug::emitAccelTypes() {
1509 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1510 "types", "types_begin");
1513 // Public name handling.
1514 // The format for the various pubnames:
1516 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1517 // for the DIE that is named.
1519 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1520 // into the CU and the index value is computed according to the type of value
1521 // for the DIE that is named.
1523 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1524 // it's the offset within the debug_info/debug_types dwo section, however, the
1525 // reference in the pubname header doesn't change.
1527 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1528 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1530 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1532 // We could have a specification DIE that has our most of our knowledge,
1533 // look for that now.
1534 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1536 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1537 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1538 Linkage = dwarf::GIEL_EXTERNAL;
1539 } else if (Die->findAttribute(dwarf::DW_AT_external))
1540 Linkage = dwarf::GIEL_EXTERNAL;
1542 switch (Die->getTag()) {
1543 case dwarf::DW_TAG_class_type:
1544 case dwarf::DW_TAG_structure_type:
1545 case dwarf::DW_TAG_union_type:
1546 case dwarf::DW_TAG_enumeration_type:
1547 return dwarf::PubIndexEntryDescriptor(
1548 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1549 ? dwarf::GIEL_STATIC
1550 : dwarf::GIEL_EXTERNAL);
1551 case dwarf::DW_TAG_typedef:
1552 case dwarf::DW_TAG_base_type:
1553 case dwarf::DW_TAG_subrange_type:
1554 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1555 case dwarf::DW_TAG_namespace:
1556 return dwarf::GIEK_TYPE;
1557 case dwarf::DW_TAG_subprogram:
1558 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1559 case dwarf::DW_TAG_variable:
1560 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1561 case dwarf::DW_TAG_enumerator:
1562 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1563 dwarf::GIEL_STATIC);
1565 return dwarf::GIEK_NONE;
1569 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1571 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1572 const MCSection *PSec =
1573 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1574 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1576 emitDebugPubSection(GnuStyle, PSec, "Names",
1577 &DwarfCompileUnit::getGlobalNames);
1580 void DwarfDebug::emitDebugPubSection(
1581 bool GnuStyle, const MCSection *PSec, StringRef Name,
1582 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1583 for (const auto &NU : CUMap) {
1584 DwarfCompileUnit *TheU = NU.second;
1586 const auto &Globals = (TheU->*Accessor)();
1588 if (Globals.empty())
1591 if (auto *Skeleton = TheU->getSkeleton())
1593 unsigned ID = TheU->getUniqueID();
1595 // Start the dwarf pubnames section.
1596 Asm->OutStreamer.SwitchSection(PSec);
1599 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1600 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1601 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1602 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1604 Asm->OutStreamer.EmitLabel(BeginLabel);
1606 Asm->OutStreamer.AddComment("DWARF Version");
1607 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1609 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1610 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1612 Asm->OutStreamer.AddComment("Compilation Unit Length");
1613 Asm->EmitInt32(TheU->getLength());
1615 // Emit the pubnames for this compilation unit.
1616 for (const auto &GI : Globals) {
1617 const char *Name = GI.getKeyData();
1618 const DIE *Entity = GI.second;
1620 Asm->OutStreamer.AddComment("DIE offset");
1621 Asm->EmitInt32(Entity->getOffset());
1624 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1625 Asm->OutStreamer.AddComment(
1626 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1627 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1628 Asm->EmitInt8(Desc.toBits());
1631 Asm->OutStreamer.AddComment("External Name");
1632 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1635 Asm->OutStreamer.AddComment("End Mark");
1637 Asm->OutStreamer.EmitLabel(EndLabel);
1641 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1642 const MCSection *PSec =
1643 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1644 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1646 emitDebugPubSection(GnuStyle, PSec, "Types",
1647 &DwarfCompileUnit::getGlobalTypes);
1650 // Emit visible names into a debug str section.
1651 void DwarfDebug::emitDebugStr() {
1652 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1653 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1656 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1657 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1658 const DITypeIdentifierMap &Map,
1659 ArrayRef<DebugLocEntry::Value> Values) {
1660 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1661 return P.isBitPiece();
1662 }) && "all values are expected to be pieces");
1663 assert(std::is_sorted(Values.begin(), Values.end()) &&
1664 "pieces are expected to be sorted");
1666 unsigned Offset = 0;
1667 for (auto Piece : Values) {
1668 DIExpression Expr = Piece.getExpression();
1669 unsigned PieceOffset = Expr.getBitPieceOffset();
1670 unsigned PieceSize = Expr.getBitPieceSize();
1671 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1672 if (Offset < PieceOffset) {
1673 // The DWARF spec seriously mandates pieces with no locations for gaps.
1674 Asm->EmitDwarfOpPiece(Streamer, PieceOffset-Offset);
1675 Offset += PieceOffset-Offset;
1677 Offset += PieceSize;
1680 DIVariable Var = Piece.getVariable();
1681 unsigned VarSize = Var.getSizeInBits(Map);
1682 assert(PieceSize+PieceOffset <= VarSize
1683 && "piece is larger than or outside of variable");
1684 assert(PieceSize != VarSize
1685 && "piece covers entire variable");
1687 emitDebugLocValue(Streamer, Piece, PieceOffset);
1692 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1693 const DebugLocEntry &Entry) {
1694 const DebugLocEntry::Value Value = Entry.getValues()[0];
1695 if (Value.isBitPiece())
1696 // Emit all pieces that belong to the same variable and range.
1697 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1699 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1700 emitDebugLocValue(Streamer, Value);
1703 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1704 const DebugLocEntry::Value &Value,
1705 unsigned PieceOffsetInBits) {
1706 DIVariable DV = Value.getVariable();
1707 DebugLocDwarfExpression DwarfExpr(*Asm, Streamer);
1710 if (Value.isInt()) {
1711 DIBasicType BTy(resolve(DV.getType()));
1712 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1713 BTy.getEncoding() == dwarf::DW_ATE_signed_char))
1714 DwarfExpr.AddSignedConstant(Value.getInt());
1716 DwarfExpr.AddUnsignedConstant(Value.getInt());
1717 } else if (Value.isLocation()) {
1718 MachineLocation Loc = Value.getLoc();
1719 DIExpression Expr = Value.getExpression();
1720 if (!Expr || (Expr.getNumElements() == 0))
1722 Asm->EmitDwarfRegOp(Streamer, Loc);
1724 // Complex address entry.
1725 if (Loc.getOffset()) {
1726 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1727 DwarfExpr.AddExpression(Expr, PieceOffsetInBits);
1729 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1733 // else ... ignore constant fp. There is not any good way to
1734 // to represent them here in dwarf.
1738 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1739 Asm->OutStreamer.AddComment("Loc expr size");
1740 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1741 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1742 Asm->EmitLabelDifference(end, begin, 2);
1743 Asm->OutStreamer.EmitLabel(begin);
1745 APByteStreamer Streamer(*Asm);
1746 emitDebugLocEntry(Streamer, Entry);
1748 Asm->OutStreamer.EmitLabel(end);
1751 // Emit locations into the debug loc section.
1752 void DwarfDebug::emitDebugLoc() {
1753 // Start the dwarf loc section.
1754 Asm->OutStreamer.SwitchSection(
1755 Asm->getObjFileLowering().getDwarfLocSection());
1756 unsigned char Size = Asm->getDataLayout().getPointerSize();
1757 for (const auto &DebugLoc : DotDebugLocEntries) {
1758 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1759 const DwarfCompileUnit *CU = DebugLoc.CU;
1760 for (const auto &Entry : DebugLoc.List) {
1761 // Set up the range. This range is relative to the entry point of the
1762 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1763 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1764 if (auto *Base = CU->getBaseAddress()) {
1765 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1766 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1768 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1769 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1772 emitDebugLocEntryLocation(Entry);
1774 Asm->OutStreamer.EmitIntValue(0, Size);
1775 Asm->OutStreamer.EmitIntValue(0, Size);
1779 void DwarfDebug::emitDebugLocDWO() {
1780 Asm->OutStreamer.SwitchSection(
1781 Asm->getObjFileLowering().getDwarfLocDWOSection());
1782 for (const auto &DebugLoc : DotDebugLocEntries) {
1783 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1784 for (const auto &Entry : DebugLoc.List) {
1785 // Just always use start_length for now - at least that's one address
1786 // rather than two. We could get fancier and try to, say, reuse an
1787 // address we know we've emitted elsewhere (the start of the function?
1788 // The start of the CU or CU subrange that encloses this range?)
1789 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1790 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1791 Asm->EmitULEB128(idx);
1792 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1794 emitDebugLocEntryLocation(Entry);
1796 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1801 const MCSymbol *Start, *End;
1804 // Emit a debug aranges section, containing a CU lookup for any
1805 // address we can tie back to a CU.
1806 void DwarfDebug::emitDebugARanges() {
1807 // Start the dwarf aranges section.
1808 Asm->OutStreamer.SwitchSection(
1809 Asm->getObjFileLowering().getDwarfARangesSection());
1811 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1815 // Build a list of sections used.
1816 std::vector<const MCSection *> Sections;
1817 for (const auto &it : SectionMap) {
1818 const MCSection *Section = it.first;
1819 Sections.push_back(Section);
1822 // Sort the sections into order.
1823 // This is only done to ensure consistent output order across different runs.
1824 std::sort(Sections.begin(), Sections.end(), SectionSort);
1826 // Build a set of address spans, sorted by CU.
1827 for (const MCSection *Section : Sections) {
1828 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1829 if (List.size() < 2)
1832 // If we have no section (e.g. common), just write out
1833 // individual spans for each symbol.
1835 for (const SymbolCU &Cur : List) {
1837 Span.Start = Cur.Sym;
1840 Spans[Cur.CU].push_back(Span);
1845 // Sort the symbols by offset within the section.
1846 std::sort(List.begin(), List.end(),
1847 [&](const SymbolCU &A, const SymbolCU &B) {
1848 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1849 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1851 // Symbols with no order assigned should be placed at the end.
1852 // (e.g. section end labels)
1860 // Build spans between each label.
1861 const MCSymbol *StartSym = List[0].Sym;
1862 for (size_t n = 1, e = List.size(); n < e; n++) {
1863 const SymbolCU &Prev = List[n - 1];
1864 const SymbolCU &Cur = List[n];
1866 // Try and build the longest span we can within the same CU.
1867 if (Cur.CU != Prev.CU) {
1869 Span.Start = StartSym;
1871 Spans[Prev.CU].push_back(Span);
1877 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1879 // Build a list of CUs used.
1880 std::vector<DwarfCompileUnit *> CUs;
1881 for (const auto &it : Spans) {
1882 DwarfCompileUnit *CU = it.first;
1886 // Sort the CU list (again, to ensure consistent output order).
1887 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1888 return A->getUniqueID() < B->getUniqueID();
1891 // Emit an arange table for each CU we used.
1892 for (DwarfCompileUnit *CU : CUs) {
1893 std::vector<ArangeSpan> &List = Spans[CU];
1895 // Describe the skeleton CU's offset and length, not the dwo file's.
1896 if (auto *Skel = CU->getSkeleton())
1899 // Emit size of content not including length itself.
1900 unsigned ContentSize =
1901 sizeof(int16_t) + // DWARF ARange version number
1902 sizeof(int32_t) + // Offset of CU in the .debug_info section
1903 sizeof(int8_t) + // Pointer Size (in bytes)
1904 sizeof(int8_t); // Segment Size (in bytes)
1906 unsigned TupleSize = PtrSize * 2;
1908 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1910 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1912 ContentSize += Padding;
1913 ContentSize += (List.size() + 1) * TupleSize;
1915 // For each compile unit, write the list of spans it covers.
1916 Asm->OutStreamer.AddComment("Length of ARange Set");
1917 Asm->EmitInt32(ContentSize);
1918 Asm->OutStreamer.AddComment("DWARF Arange version number");
1919 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1920 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1921 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1922 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1923 Asm->EmitInt8(PtrSize);
1924 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1927 Asm->OutStreamer.EmitFill(Padding, 0xff);
1929 for (const ArangeSpan &Span : List) {
1930 Asm->EmitLabelReference(Span.Start, PtrSize);
1932 // Calculate the size as being from the span start to it's end.
1934 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1936 // For symbols without an end marker (e.g. common), we
1937 // write a single arange entry containing just that one symbol.
1938 uint64_t Size = SymSize[Span.Start];
1942 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1946 Asm->OutStreamer.AddComment("ARange terminator");
1947 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1948 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1952 // Emit visible names into a debug ranges section.
1953 void DwarfDebug::emitDebugRanges() {
1954 // Start the dwarf ranges section.
1955 Asm->OutStreamer.SwitchSection(
1956 Asm->getObjFileLowering().getDwarfRangesSection());
1958 // Size for our labels.
1959 unsigned char Size = Asm->getDataLayout().getPointerSize();
1961 // Grab the specific ranges for the compile units in the module.
1962 for (const auto &I : CUMap) {
1963 DwarfCompileUnit *TheCU = I.second;
1965 if (auto *Skel = TheCU->getSkeleton())
1968 // Iterate over the misc ranges for the compile units in the module.
1969 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1970 // Emit our symbol so we can find the beginning of the range.
1971 Asm->OutStreamer.EmitLabel(List.getSym());
1973 for (const RangeSpan &Range : List.getRanges()) {
1974 const MCSymbol *Begin = Range.getStart();
1975 const MCSymbol *End = Range.getEnd();
1976 assert(Begin && "Range without a begin symbol?");
1977 assert(End && "Range without an end symbol?");
1978 if (auto *Base = TheCU->getBaseAddress()) {
1979 Asm->EmitLabelDifference(Begin, Base, Size);
1980 Asm->EmitLabelDifference(End, Base, Size);
1982 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1983 Asm->OutStreamer.EmitSymbolValue(End, Size);
1987 // And terminate the list with two 0 values.
1988 Asm->OutStreamer.EmitIntValue(0, Size);
1989 Asm->OutStreamer.EmitIntValue(0, Size);
1994 // DWARF5 Experimental Separate Dwarf emitters.
1996 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1997 std::unique_ptr<DwarfUnit> NewU) {
1998 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1999 U.getCUNode().getSplitDebugFilename());
2001 if (!CompilationDir.empty())
2002 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2004 addGnuPubAttributes(*NewU, Die);
2006 SkeletonHolder.addUnit(std::move(NewU));
2009 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2010 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2011 // DW_AT_addr_base, DW_AT_ranges_base.
2012 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2014 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2015 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2016 DwarfCompileUnit &NewCU = *OwnedUnit;
2017 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2018 DwarfInfoSectionSym);
2020 NewCU.initStmtList(DwarfLineSectionSym);
2022 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2027 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2028 // compile units that would normally be in debug_info.
2029 void DwarfDebug::emitDebugInfoDWO() {
2030 assert(useSplitDwarf() && "No split dwarf debug info?");
2031 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2032 // emit relocations into the dwo file.
2033 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2036 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2037 // abbreviations for the .debug_info.dwo section.
2038 void DwarfDebug::emitDebugAbbrevDWO() {
2039 assert(useSplitDwarf() && "No split dwarf?");
2040 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2043 void DwarfDebug::emitDebugLineDWO() {
2044 assert(useSplitDwarf() && "No split dwarf?");
2045 Asm->OutStreamer.SwitchSection(
2046 Asm->getObjFileLowering().getDwarfLineDWOSection());
2047 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2050 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2051 // string section and is identical in format to traditional .debug_str
2053 void DwarfDebug::emitDebugStrDWO() {
2054 assert(useSplitDwarf() && "No split dwarf?");
2055 const MCSection *OffSec =
2056 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2057 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2061 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2062 if (!useSplitDwarf())
2065 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2066 return &SplitTypeUnitFileTable;
2069 static uint64_t makeTypeSignature(StringRef Identifier) {
2071 Hash.update(Identifier);
2072 // ... take the least significant 8 bytes and return those. Our MD5
2073 // implementation always returns its results in little endian, swap bytes
2075 MD5::MD5Result Result;
2077 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2080 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2081 StringRef Identifier, DIE &RefDie,
2082 DICompositeType CTy) {
2083 // Fast path if we're building some type units and one has already used the
2084 // address pool we know we're going to throw away all this work anyway, so
2085 // don't bother building dependent types.
2086 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2089 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2091 CU.addDIETypeSignature(RefDie, *TU);
2095 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2096 AddrPool.resetUsedFlag();
2098 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2099 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2100 this, &InfoHolder, getDwoLineTable(CU));
2101 DwarfTypeUnit &NewTU = *OwnedUnit;
2102 DIE &UnitDie = NewTU.getUnitDie();
2104 TypeUnitsUnderConstruction.push_back(
2105 std::make_pair(std::move(OwnedUnit), CTy));
2107 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2110 uint64_t Signature = makeTypeSignature(Identifier);
2111 NewTU.setTypeSignature(Signature);
2113 if (useSplitDwarf())
2114 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2116 CU.applyStmtList(UnitDie);
2118 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2121 NewTU.setType(NewTU.createTypeDIE(CTy));
2124 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2125 TypeUnitsUnderConstruction.clear();
2127 // Types referencing entries in the address table cannot be placed in type
2129 if (AddrPool.hasBeenUsed()) {
2131 // Remove all the types built while building this type.
2132 // This is pessimistic as some of these types might not be dependent on
2133 // the type that used an address.
2134 for (const auto &TU : TypeUnitsToAdd)
2135 DwarfTypeUnits.erase(TU.second);
2137 // Construct this type in the CU directly.
2138 // This is inefficient because all the dependent types will be rebuilt
2139 // from scratch, including building them in type units, discovering that
2140 // they depend on addresses, throwing them out and rebuilding them.
2141 CU.constructTypeDIE(RefDie, CTy);
2145 // If the type wasn't dependent on fission addresses, finish adding the type
2146 // and all its dependent types.
2147 for (auto &TU : TypeUnitsToAdd)
2148 InfoHolder.addUnit(std::move(TU.first));
2150 CU.addDIETypeSignature(RefDie, NewTU);
2153 // Accelerator table mutators - add each name along with its companion
2154 // DIE to the proper table while ensuring that the name that we're going
2155 // to reference is in the string table. We do this since the names we
2156 // add may not only be identical to the names in the DIE.
2157 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2158 if (!useDwarfAccelTables())
2160 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2164 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2165 if (!useDwarfAccelTables())
2167 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2171 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2172 if (!useDwarfAccelTables())
2174 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2178 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2179 if (!useDwarfAccelTables())
2181 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),