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"
16 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.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/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), FirstCU(nullptr), PrevLabel(nullptr),
174 InfoHolder(A, *this, "info_string", DIEValueAllocator),
175 UsedNonDefaultText(false),
176 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
177 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
178 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
179 dwarf::DW_FORM_data4)),
180 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
181 dwarf::DW_FORM_data4)),
182 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
183 dwarf::DW_FORM_data4)),
184 AccelTypes(TypeAtoms) {
186 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
187 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
188 DwarfLineSectionSym = nullptr;
189 DwarfAddrSectionSym = nullptr;
190 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
191 FunctionBeginSym = FunctionEndSym = nullptr;
195 // Turn on accelerator tables for Darwin by default, pubnames by
196 // default for non-Darwin, and handle split dwarf.
197 if (DwarfAccelTables == Default)
198 HasDwarfAccelTables = IsDarwin;
200 HasDwarfAccelTables = DwarfAccelTables == Enable;
202 if (SplitDwarf == Default)
203 HasSplitDwarf = false;
205 HasSplitDwarf = SplitDwarf == Enable;
207 if (DwarfPubSections == Default)
208 HasDwarfPubSections = !IsDarwin;
210 HasDwarfPubSections = DwarfPubSections == Enable;
212 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
213 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
214 : MMI->getModule()->getDwarfVersion();
216 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
219 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
224 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
225 DwarfDebug::~DwarfDebug() { }
227 // Switch to the specified MCSection and emit an assembler
228 // temporary label to it if SymbolStem is specified.
229 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
230 const char *SymbolStem = nullptr) {
231 Asm->OutStreamer.SwitchSection(Section);
235 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
236 Asm->OutStreamer.EmitLabel(TmpSym);
240 static bool isObjCClass(StringRef Name) {
241 return Name.startswith("+") || Name.startswith("-");
244 static bool hasObjCCategory(StringRef Name) {
245 if (!isObjCClass(Name))
248 return Name.find(") ") != StringRef::npos;
251 static void getObjCClassCategory(StringRef In, StringRef &Class,
252 StringRef &Category) {
253 if (!hasObjCCategory(In)) {
254 Class = In.slice(In.find('[') + 1, In.find(' '));
259 Class = In.slice(In.find('[') + 1, In.find('('));
260 Category = In.slice(In.find('[') + 1, In.find(' '));
264 static StringRef getObjCMethodName(StringRef In) {
265 return In.slice(In.find(' ') + 1, In.find(']'));
268 // Helper for sorting sections into a stable output order.
269 static bool SectionSort(const MCSection *A, const MCSection *B) {
270 std::string LA = (A ? A->getLabelBeginName() : "");
271 std::string LB = (B ? B->getLabelBeginName() : "");
275 // Add the various names to the Dwarf accelerator table names.
276 // TODO: Determine whether or not we should add names for programs
277 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
278 // is only slightly different than the lookup of non-standard ObjC names.
279 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
280 if (!SP.isDefinition())
282 addAccelName(SP.getName(), Die);
284 // If the linkage name is different than the name, go ahead and output
285 // that as well into the name table.
286 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
287 addAccelName(SP.getLinkageName(), Die);
289 // If this is an Objective-C selector name add it to the ObjC accelerator
291 if (isObjCClass(SP.getName())) {
292 StringRef Class, Category;
293 getObjCClassCategory(SP.getName(), Class, Category);
294 addAccelObjC(Class, Die);
296 addAccelObjC(Category, Die);
297 // Also add the base method name to the name table.
298 addAccelName(getObjCMethodName(SP.getName()), Die);
302 /// isSubprogramContext - Return true if Context is either a subprogram
303 /// or another context nested inside a subprogram.
304 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
307 DIDescriptor D(Context);
308 if (D.isSubprogram())
311 return isSubprogramContext(resolve(DIType(Context).getContext()));
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 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
335 assert(Scope && Scope->getScopeNode());
336 assert(Scope->isAbstractScope());
337 assert(!Scope->getInlinedAt());
339 const MDNode *SP = Scope->getScopeNode();
341 DIE *&AbsDef = AbstractSPDies[SP];
345 ProcessedSPNodes.insert(SP);
347 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
348 // was inlined from another compile unit.
349 AbsDef = &SPMap[SP]->constructAbstractSubprogramScopeDIE(Scope);
352 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
353 if (!GenerateGnuPubSections)
356 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
359 // Create new DwarfCompileUnit for the given metadata node with tag
360 // DW_TAG_compile_unit.
361 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
362 StringRef FN = DIUnit.getFilename();
363 CompilationDir = DIUnit.getDirectory();
365 auto OwnedUnit = make_unique<DwarfCompileUnit>(
366 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
367 DwarfCompileUnit &NewCU = *OwnedUnit;
368 DIE &Die = NewCU.getUnitDie();
369 InfoHolder.addUnit(std::move(OwnedUnit));
371 // LTO with assembly output shares a single line table amongst multiple CUs.
372 // To avoid the compilation directory being ambiguous, let the line table
373 // explicitly describe the directory of all files, never relying on the
374 // compilation directory.
375 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
376 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
377 NewCU.getUniqueID(), CompilationDir);
379 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
380 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
381 DIUnit.getLanguage());
382 NewCU.addString(Die, dwarf::DW_AT_name, FN);
384 if (!useSplitDwarf()) {
385 NewCU.initStmtList(DwarfLineSectionSym);
387 // If we're using split dwarf the compilation dir is going to be in the
388 // skeleton CU and so we don't need to duplicate it here.
389 if (!CompilationDir.empty())
390 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
392 addGnuPubAttributes(NewCU, Die);
395 if (DIUnit.isOptimized())
396 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
398 StringRef Flags = DIUnit.getFlags();
400 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
402 if (unsigned RVer = DIUnit.getRunTimeVersion())
403 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
404 dwarf::DW_FORM_data1, RVer);
409 if (useSplitDwarf()) {
410 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
411 DwarfInfoDWOSectionSym);
412 NewCU.setSkeleton(constructSkeletonCU(NewCU));
414 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
415 DwarfInfoSectionSym);
417 CUMap.insert(std::make_pair(DIUnit, &NewCU));
418 CUDieMap.insert(std::make_pair(&Die, &NewCU));
422 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
424 DIImportedEntity Module(N);
425 assert(Module.Verify());
426 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
427 D->addChild(TheCU.constructImportedEntityDIE(Module));
430 // Emit all Dwarf sections that should come prior to the content. Create
431 // global DIEs and emit initial debug info sections. This is invoked by
432 // the target AsmPrinter.
433 void DwarfDebug::beginModule() {
434 if (DisableDebugInfoPrinting)
437 const Module *M = MMI->getModule();
439 FunctionDIs = makeSubprogramMap(*M);
441 // If module has named metadata anchors then use them, otherwise scan the
442 // module using debug info finder to collect debug info.
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 P.second->finishSubprogramDefinition(DISubprogram(P.first));
522 // Collect info for variables that were optimized out.
523 void DwarfDebug::collectDeadVariables() {
524 const Module *M = MMI->getModule();
526 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
527 for (MDNode *N : CU_Nodes->operands()) {
528 DICompileUnit TheCU(N);
529 // Construct subprogram DIE and add variables DIEs.
530 DwarfCompileUnit *SPCU =
531 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
532 assert(SPCU && "Unable to find Compile Unit!");
533 DIArray Subprograms = TheCU.getSubprograms();
534 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
535 DISubprogram SP(Subprograms.getElement(i));
536 if (ProcessedSPNodes.count(SP) != 0)
538 assert(SP.isSubprogram() &&
539 "CU's subprogram list contains a non-subprogram");
540 assert(SP.isDefinition() &&
541 "CU's subprogram list contains a subprogram declaration");
542 DIArray Variables = SP.getVariables();
543 if (Variables.getNumElements() == 0)
546 DIE *SPDIE = AbstractSPDies.lookup(SP);
548 SPDIE = SPCU->getDIE(SP);
550 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
551 DIVariable DV(Variables.getElement(vi));
552 assert(DV.isVariable());
553 DbgVariable NewVar(DV, DIExpression(nullptr), this);
554 auto VariableDie = SPCU->constructVariableDIE(NewVar);
555 SPCU->applyVariableAttributes(NewVar, *VariableDie);
556 SPDIE->addChild(std::move(VariableDie));
563 void DwarfDebug::finalizeModuleInfo() {
564 finishSubprogramDefinitions();
566 finishVariableDefinitions();
568 // Collect info for variables that were optimized out.
569 collectDeadVariables();
571 // Handle anything that needs to be done on a per-unit basis after
572 // all other generation.
573 for (const auto &TheU : getUnits()) {
574 // Emit DW_AT_containing_type attribute to connect types with their
575 // vtable holding type.
576 TheU->constructContainingTypeDIEs();
578 // Add CU specific attributes if we need to add any.
579 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
580 // If we're splitting the dwarf out now that we've got the entire
581 // CU then add the dwo id to it.
582 DwarfCompileUnit *SkCU =
583 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
584 if (useSplitDwarf()) {
585 // Emit a unique identifier for this CU.
586 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
587 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
588 dwarf::DW_FORM_data8, ID);
589 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
590 dwarf::DW_FORM_data8, ID);
592 // We don't keep track of which addresses are used in which CU so this
593 // is a bit pessimistic under LTO.
594 if (!AddrPool.isEmpty())
595 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
596 DwarfAddrSectionSym, DwarfAddrSectionSym);
597 if (!TheU->getRangeLists().empty())
598 SkCU->addSectionLabel(
599 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
600 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
603 // If we have code split among multiple sections or non-contiguous
604 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
605 // remain in the .o file, otherwise add a DW_AT_low_pc.
606 // FIXME: We should use ranges allow reordering of code ala
607 // .subsections_via_symbols in mach-o. This would mean turning on
608 // ranges for all subprogram DIEs for mach-o.
609 DwarfCompileUnit &U =
610 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
611 unsigned NumRanges = TheU->getRanges().size();
614 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
615 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
616 DwarfDebugRangeSectionSym);
618 // A DW_AT_low_pc attribute may also be specified in combination with
619 // DW_AT_ranges to specify the default base address for use in
620 // location lists (see Section 2.6.2) and range lists (see Section
622 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
625 RangeSpan &Range = TheU->getRanges().back();
626 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
632 // Compute DIE offsets and sizes.
633 InfoHolder.computeSizeAndOffsets();
635 SkeletonHolder.computeSizeAndOffsets();
638 void DwarfDebug::endSections() {
639 // Filter labels by section.
640 for (const SymbolCU &SCU : ArangeLabels) {
641 if (SCU.Sym->isInSection()) {
642 // Make a note of this symbol and it's section.
643 const MCSection *Section = &SCU.Sym->getSection();
644 if (!Section->getKind().isMetadata())
645 SectionMap[Section].push_back(SCU);
647 // Some symbols (e.g. common/bss on mach-o) can have no section but still
648 // appear in the output. This sucks as we rely on sections to build
649 // arange spans. We can do it without, but it's icky.
650 SectionMap[nullptr].push_back(SCU);
654 // Build a list of sections used.
655 std::vector<const MCSection *> Sections;
656 for (const auto &it : SectionMap) {
657 const MCSection *Section = it.first;
658 Sections.push_back(Section);
661 // Sort the sections into order.
662 // This is only done to ensure consistent output order across different runs.
663 std::sort(Sections.begin(), Sections.end(), SectionSort);
665 // Add terminating symbols for each section.
666 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
667 const MCSection *Section = Sections[ID];
668 MCSymbol *Sym = nullptr;
671 // We can't call MCSection::getLabelEndName, as it's only safe to do so
672 // if we know the section name up-front. For user-created sections, the
673 // resulting label may not be valid to use as a label. (section names can
674 // use a greater set of characters on some systems)
675 Sym = Asm->GetTempSymbol("debug_end", ID);
676 Asm->OutStreamer.SwitchSection(Section);
677 Asm->OutStreamer.EmitLabel(Sym);
680 // Insert a final terminator.
681 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
685 // Emit all Dwarf sections that should come after the content.
686 void DwarfDebug::endModule() {
687 assert(CurFn == nullptr);
688 assert(CurMI == nullptr);
693 // End any existing sections.
694 // TODO: Does this need to happen?
697 // Finalize the debug info for the module.
698 finalizeModuleInfo();
702 // Emit all the DIEs into a debug info section.
705 // Corresponding abbreviations into a abbrev section.
708 // Emit info into a debug aranges section.
709 if (GenerateARangeSection)
712 // Emit info into a debug ranges section.
715 if (useSplitDwarf()) {
718 emitDebugAbbrevDWO();
721 // Emit DWO addresses.
722 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
724 // Emit info into a debug loc section.
727 // Emit info into the dwarf accelerator table sections.
728 if (useDwarfAccelTables()) {
731 emitAccelNamespaces();
735 // Emit the pubnames and pubtypes sections if requested.
736 if (HasDwarfPubSections) {
737 emitDebugPubNames(GenerateGnuPubSections);
738 emitDebugPubTypes(GenerateGnuPubSections);
743 AbstractVariables.clear();
745 // Reset these for the next Module if we have one.
749 // Find abstract variable, if any, associated with Var.
750 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
751 DIVariable &Cleansed) {
752 LLVMContext &Ctx = DV->getContext();
753 // More then one inlined variable corresponds to one abstract variable.
754 // FIXME: This duplication of variables when inlining should probably be
755 // removed. It's done to allow each DIVariable to describe its location
756 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
757 // make it accurate then remove this duplication/cleansing stuff.
758 Cleansed = cleanseInlinedVariable(DV, Ctx);
759 auto I = AbstractVariables.find(Cleansed);
760 if (I != AbstractVariables.end())
761 return I->second.get();
765 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
767 return getExistingAbstractVariable(DV, Cleansed);
770 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
771 LexicalScope *Scope) {
772 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
773 InfoHolder.addNonArgumentScopeVariable(Scope, AbsDbgVariable.get());
774 AbstractVariables[Var] = std::move(AbsDbgVariable);
777 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
778 const MDNode *ScopeNode) {
779 DIVariable Cleansed = DV;
780 if (getExistingAbstractVariable(DV, Cleansed))
783 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
787 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
788 const MDNode *ScopeNode) {
789 DIVariable Cleansed = DV;
790 if (getExistingAbstractVariable(DV, Cleansed))
793 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
794 createAbstractVariable(Cleansed, Scope);
797 // Collect variable information from side table maintained by MMI.
798 void DwarfDebug::collectVariableInfoFromMMITable(
799 SmallPtrSetImpl<const MDNode *> &Processed) {
800 for (const auto &VI : MMI->getVariableDbgInfo()) {
803 Processed.insert(VI.Var);
804 DIVariable DV(VI.Var);
805 DIExpression Expr(VI.Expr);
806 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
808 // If variable scope is not found then skip this variable.
812 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
813 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
814 DbgVariable *RegVar = ConcreteVariables.back().get();
815 RegVar->setFrameIndex(VI.Slot);
816 addScopeVariable(Scope, RegVar);
820 // Get .debug_loc entry for the instruction range starting at MI.
821 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
822 const MDNode *Expr = MI->getDebugExpression();
823 const MDNode *Var = MI->getDebugVariable();
825 assert(MI->getNumOperands() == 4);
826 if (MI->getOperand(0).isReg()) {
827 MachineLocation MLoc;
828 // If the second operand is an immediate, this is a
829 // register-indirect address.
830 if (!MI->getOperand(1).isImm())
831 MLoc.set(MI->getOperand(0).getReg());
833 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
834 return DebugLocEntry::Value(Var, Expr, MLoc);
836 if (MI->getOperand(0).isImm())
837 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
838 if (MI->getOperand(0).isFPImm())
839 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
840 if (MI->getOperand(0).isCImm())
841 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
843 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
846 /// Determine whether two variable pieces overlap.
847 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
848 if (!P1.isVariablePiece() || !P2.isVariablePiece())
850 unsigned l1 = P1.getPieceOffset();
851 unsigned l2 = P2.getPieceOffset();
852 unsigned r1 = l1 + P1.getPieceSize();
853 unsigned r2 = l2 + P2.getPieceSize();
854 // True where [l1,r1[ and [r1,r2[ overlap.
855 return (l1 < r2) && (l2 < r1);
858 /// Build the location list for all DBG_VALUEs in the function that
859 /// describe the same variable. If the ranges of several independent
860 /// pieces of the same variable overlap partially, split them up and
861 /// combine the ranges. The resulting DebugLocEntries are will have
862 /// strict monotonically increasing begin addresses and will never
867 // Ranges History [var, loc, piece ofs size]
868 // 0 | [x, (reg0, piece 0, 32)]
869 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
871 // 3 | [clobber reg0]
872 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
876 // [0-1] [x, (reg0, piece 0, 32)]
877 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
878 // [3-4] [x, (reg1, piece 32, 32)]
879 // [4- ] [x, (mem, piece 0, 64)]
881 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
882 const DbgValueHistoryMap::InstrRanges &Ranges) {
883 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
885 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
886 const MachineInstr *Begin = I->first;
887 const MachineInstr *End = I->second;
888 assert(Begin->isDebugValue() && "Invalid History entry");
890 // Check if a variable is inaccessible in this range.
891 if (Begin->getNumOperands() > 1 &&
892 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
897 // If this piece overlaps with any open ranges, truncate them.
898 DIExpression DIExpr = Begin->getDebugExpression();
899 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
900 [&](DebugLocEntry::Value R) {
901 return piecesOverlap(DIExpr, R.getExpression());
903 OpenRanges.erase(Last, OpenRanges.end());
905 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
906 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
908 const MCSymbol *EndLabel;
910 EndLabel = getLabelAfterInsn(End);
911 else if (std::next(I) == Ranges.end())
912 EndLabel = FunctionEndSym;
914 EndLabel = getLabelBeforeInsn(std::next(I)->first);
915 assert(EndLabel && "Forgot label after instruction ending a range!");
917 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
919 auto Value = getDebugLocValue(Begin);
920 DebugLocEntry Loc(StartLabel, EndLabel, Value);
921 bool couldMerge = false;
923 // If this is a piece, it may belong to the current DebugLocEntry.
924 if (DIExpr.isVariablePiece()) {
925 // Add this value to the list of open ranges.
926 OpenRanges.push_back(Value);
928 // Attempt to add the piece to the last entry.
929 if (!DebugLoc.empty())
930 if (DebugLoc.back().MergeValues(Loc))
935 // Need to add a new DebugLocEntry. Add all values from still
936 // valid non-overlapping pieces.
937 if (OpenRanges.size())
938 Loc.addValues(OpenRanges);
940 DebugLoc.push_back(std::move(Loc));
943 // Attempt to coalesce the ranges of two otherwise identical
945 auto CurEntry = DebugLoc.rbegin();
946 auto PrevEntry = std::next(CurEntry);
947 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
951 dbgs() << CurEntry->getValues().size() << " Values:\n";
952 for (auto Value : CurEntry->getValues()) {
953 Value.getVariable()->dump();
954 Value.getExpression()->dump();
962 // Find variables for each lexical scope.
964 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
965 SmallPtrSetImpl<const MDNode *> &Processed) {
966 // Grab the variable info that was squirreled away in the MMI side-table.
967 collectVariableInfoFromMMITable(Processed);
969 for (const auto &I : DbgValues) {
970 DIVariable DV(I.first);
971 if (Processed.count(DV))
974 // Instruction ranges, specifying where DV is accessible.
975 const auto &Ranges = I.second;
979 LexicalScope *Scope = nullptr;
980 if (MDNode *IA = DV.getInlinedAt()) {
981 DebugLoc DL = DebugLoc::getFromDILocation(IA);
982 Scope = LScopes.findInlinedScope(DebugLoc::get(
983 DL.getLine(), DL.getCol(), DV.getContext(), IA));
985 Scope = LScopes.findLexicalScope(DV.getContext());
986 // If variable scope is not found then skip this variable.
990 Processed.insert(DV);
991 const MachineInstr *MInsn = Ranges.front().first;
992 assert(MInsn->isDebugValue() && "History must begin with debug value");
993 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
994 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
995 DbgVariable *RegVar = ConcreteVariables.back().get();
996 addScopeVariable(Scope, RegVar);
998 // Check if the first DBG_VALUE is valid for the rest of the function.
999 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1002 // Handle multiple DBG_VALUE instructions describing one variable.
1003 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1005 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1006 DebugLocList &LocList = DotDebugLocEntries.back();
1007 LocList.CU = &TheCU;
1009 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1011 // Build the location list for this variable.
1012 buildLocationList(LocList.List, Ranges);
1015 // Collect info for variables that were optimized out.
1016 DIArray Variables = SP.getVariables();
1017 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1018 DIVariable DV(Variables.getElement(i));
1019 assert(DV.isVariable());
1020 if (!Processed.insert(DV))
1022 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1023 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1024 DIExpression NoExpr;
1025 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
1026 addScopeVariable(Scope, ConcreteVariables.back().get());
1031 // Return Label preceding the instruction.
1032 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1033 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1034 assert(Label && "Didn't insert label before instruction");
1038 // Return Label immediately following the instruction.
1039 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1040 return LabelsAfterInsn.lookup(MI);
1043 // Process beginning of an instruction.
1044 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1045 assert(CurMI == nullptr);
1047 // Check if source location changes, but ignore DBG_VALUE locations.
1048 if (!MI->isDebugValue()) {
1049 DebugLoc DL = MI->getDebugLoc();
1050 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1053 if (DL == PrologEndLoc) {
1054 Flags |= DWARF2_FLAG_PROLOGUE_END;
1055 PrologEndLoc = DebugLoc();
1057 if (PrologEndLoc.isUnknown())
1058 Flags |= DWARF2_FLAG_IS_STMT;
1060 if (!DL.isUnknown()) {
1061 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1062 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1064 recordSourceLine(0, 0, nullptr, 0);
1068 // Insert labels where requested.
1069 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1070 LabelsBeforeInsn.find(MI);
1073 if (I == LabelsBeforeInsn.end())
1076 // Label already assigned.
1081 PrevLabel = MMI->getContext().CreateTempSymbol();
1082 Asm->OutStreamer.EmitLabel(PrevLabel);
1084 I->second = PrevLabel;
1087 // Process end of an instruction.
1088 void DwarfDebug::endInstruction() {
1089 assert(CurMI != nullptr);
1090 // Don't create a new label after DBG_VALUE instructions.
1091 // They don't generate code.
1092 if (!CurMI->isDebugValue())
1093 PrevLabel = nullptr;
1095 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1096 LabelsAfterInsn.find(CurMI);
1100 if (I == LabelsAfterInsn.end())
1103 // Label already assigned.
1107 // We need a label after this instruction.
1109 PrevLabel = MMI->getContext().CreateTempSymbol();
1110 Asm->OutStreamer.EmitLabel(PrevLabel);
1112 I->second = PrevLabel;
1115 // Each LexicalScope has first instruction and last instruction to mark
1116 // beginning and end of a scope respectively. Create an inverse map that list
1117 // scopes starts (and ends) with an instruction. One instruction may start (or
1118 // end) multiple scopes. Ignore scopes that are not reachable.
1119 void DwarfDebug::identifyScopeMarkers() {
1120 SmallVector<LexicalScope *, 4> WorkList;
1121 WorkList.push_back(LScopes.getCurrentFunctionScope());
1122 while (!WorkList.empty()) {
1123 LexicalScope *S = WorkList.pop_back_val();
1125 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1126 if (!Children.empty())
1127 WorkList.append(Children.begin(), Children.end());
1129 if (S->isAbstractScope())
1132 for (const InsnRange &R : S->getRanges()) {
1133 assert(R.first && "InsnRange does not have first instruction!");
1134 assert(R.second && "InsnRange does not have second instruction!");
1135 requestLabelBeforeInsn(R.first);
1136 requestLabelAfterInsn(R.second);
1141 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1142 // First known non-DBG_VALUE and non-frame setup location marks
1143 // the beginning of the function body.
1144 for (const auto &MBB : *MF)
1145 for (const auto &MI : MBB)
1146 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1147 !MI.getDebugLoc().isUnknown())
1148 return MI.getDebugLoc();
1152 // Gather pre-function debug information. Assumes being called immediately
1153 // after the function entry point has been emitted.
1154 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1157 // If there's no debug info for the function we're not going to do anything.
1158 if (!MMI->hasDebugInfo())
1161 auto DI = FunctionDIs.find(MF->getFunction());
1162 if (DI == FunctionDIs.end())
1165 // Grab the lexical scopes for the function, if we don't have any of those
1166 // then we're not going to be able to do anything.
1167 LScopes.initialize(*MF);
1168 if (LScopes.empty())
1171 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1173 // Make sure that each lexical scope will have a begin/end label.
1174 identifyScopeMarkers();
1176 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1177 // belongs to so that we add to the correct per-cu line table in the
1179 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1180 // FnScope->getScopeNode() and DI->second should represent the same function,
1181 // though they may not be the same MDNode due to inline functions merged in
1182 // LTO where the debug info metadata still differs (either due to distinct
1183 // written differences - two versions of a linkonce_odr function
1184 // written/copied into two separate files, or some sub-optimal metadata that
1185 // isn't structurally identical (see: file path/name info from clang, which
1186 // includes the directory of the cpp file being built, even when the file name
1187 // is absolute (such as an <> lookup header)))
1188 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1189 assert(TheCU && "Unable to find compile unit!");
1190 if (Asm->OutStreamer.hasRawTextSupport())
1191 // Use a single line table if we are generating assembly.
1192 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1194 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1196 // Emit a label for the function so that we have a beginning address.
1197 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1198 // Assumes in correct section after the entry point.
1199 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1201 // Calculate history for local variables.
1202 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1205 // Request labels for the full history.
1206 for (const auto &I : DbgValues) {
1207 const auto &Ranges = I.second;
1211 // The first mention of a function argument gets the FunctionBeginSym
1212 // label, so arguments are visible when breaking at function entry.
1213 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1214 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1215 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1216 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1217 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1218 // Mark all non-overlapping initial pieces.
1219 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1220 DIExpression Piece = I->first->getDebugExpression();
1221 if (std::all_of(Ranges.begin(), I,
1222 [&](DbgValueHistoryMap::InstrRange Pred) {
1223 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1225 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1232 for (const auto &Range : Ranges) {
1233 requestLabelBeforeInsn(Range.first);
1235 requestLabelAfterInsn(Range.second);
1239 PrevInstLoc = DebugLoc();
1240 PrevLabel = FunctionBeginSym;
1242 // Record beginning of function.
1243 PrologEndLoc = findPrologueEndLoc(MF);
1244 if (!PrologEndLoc.isUnknown()) {
1245 DebugLoc FnStartDL =
1246 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1248 FnStartDL.getLine(), FnStartDL.getCol(),
1249 FnStartDL.getScope(MF->getFunction()->getContext()),
1250 // We'd like to list the prologue as "not statements" but GDB behaves
1251 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1252 DWARF2_FLAG_IS_STMT);
1256 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1257 if (InfoHolder.addCurrentFnArgument(Var, LS))
1259 InfoHolder.addNonArgumentScopeVariable(LS, Var);
1262 // Gather and emit post-function debug information.
1263 void DwarfDebug::endFunction(const MachineFunction *MF) {
1264 assert(CurFn == MF &&
1265 "endFunction should be called with the same function as beginFunction");
1267 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1268 !FunctionDIs.count(MF->getFunction())) {
1269 // If we don't have a lexical scope for this function then there will
1270 // be a hole in the range information. Keep note of this by setting the
1271 // previously used section to nullptr.
1277 // Define end label for subprogram.
1278 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1279 // Assumes in correct section after the entry point.
1280 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1282 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1283 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1285 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1286 DISubprogram SP(FnScope->getScopeNode());
1287 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1289 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1290 collectVariableInfo(TheCU, SP, ProcessedVars);
1292 // Add the range of this function to the list of ranges for the CU.
1293 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1295 // Under -gmlt, skip building the subprogram if there are no inlined
1296 // subroutines inside it.
1297 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1298 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1299 assert(ScopeVariables.empty());
1300 assert(CurrentFnArguments.empty());
1301 assert(DbgValues.empty());
1302 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1303 // by a -gmlt CU. Add a test and remove this assertion.
1304 assert(AbstractVariables.empty());
1305 LabelsBeforeInsn.clear();
1306 LabelsAfterInsn.clear();
1307 PrevLabel = nullptr;
1313 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1315 // Construct abstract scopes.
1316 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1317 DISubprogram SP(AScope->getScopeNode());
1318 assert(SP.isSubprogram());
1319 // Collect info for variables that were optimized out.
1320 DIArray Variables = SP.getVariables();
1321 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1322 DIVariable DV(Variables.getElement(i));
1323 assert(DV && DV.isVariable());
1324 if (!ProcessedVars.insert(DV))
1326 ensureAbstractVariableIsCreated(DV, DV.getContext());
1327 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1328 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1330 constructAbstractSubprogramScopeDIE(AScope);
1333 TheCU.constructSubprogramScopeDIE(FnScope);
1336 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1337 // DbgVariables except those that are also in AbstractVariables (since they
1338 // can be used cross-function)
1339 ScopeVariables.clear();
1340 CurrentFnArguments.clear();
1342 LabelsBeforeInsn.clear();
1343 LabelsAfterInsn.clear();
1344 PrevLabel = nullptr;
1348 // Register a source line with debug info. Returns the unique label that was
1349 // emitted and which provides correspondence to the source line list.
1350 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1355 unsigned Discriminator = 0;
1356 if (DIScope Scope = DIScope(S)) {
1357 assert(Scope.isScope());
1358 Fn = Scope.getFilename();
1359 Dir = Scope.getDirectory();
1360 if (Scope.isLexicalBlockFile())
1361 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1363 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1364 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1365 .getOrCreateSourceID(Fn, Dir);
1367 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1371 //===----------------------------------------------------------------------===//
1373 //===----------------------------------------------------------------------===//
1375 // Emit initial Dwarf sections with a label at the start of each one.
1376 void DwarfDebug::emitSectionLabels() {
1377 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1379 // Dwarf sections base addresses.
1380 DwarfInfoSectionSym =
1381 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1382 if (useSplitDwarf()) {
1383 DwarfInfoDWOSectionSym =
1384 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1385 DwarfTypesDWOSectionSym =
1386 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1388 DwarfAbbrevSectionSym =
1389 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1390 if (useSplitDwarf())
1391 DwarfAbbrevDWOSectionSym = emitSectionSym(
1392 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1393 if (GenerateARangeSection)
1394 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1396 DwarfLineSectionSym =
1397 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1398 if (GenerateGnuPubSections) {
1399 DwarfGnuPubNamesSectionSym =
1400 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1401 DwarfGnuPubTypesSectionSym =
1402 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1403 } else if (HasDwarfPubSections) {
1404 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1405 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1408 DwarfStrSectionSym =
1409 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1410 if (useSplitDwarf()) {
1411 DwarfStrDWOSectionSym =
1412 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1413 DwarfAddrSectionSym =
1414 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1415 DwarfDebugLocSectionSym =
1416 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1418 DwarfDebugLocSectionSym =
1419 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1420 DwarfDebugRangeSectionSym =
1421 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1424 // Recursively emits a debug information entry.
1425 void DwarfDebug::emitDIE(DIE &Die) {
1426 // Get the abbreviation for this DIE.
1427 const DIEAbbrev &Abbrev = Die.getAbbrev();
1429 // Emit the code (index) for the abbreviation.
1430 if (Asm->isVerbose())
1431 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1432 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1433 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1434 dwarf::TagString(Abbrev.getTag()));
1435 Asm->EmitULEB128(Abbrev.getNumber());
1437 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1438 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1440 // Emit the DIE attribute values.
1441 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1442 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1443 dwarf::Form Form = AbbrevData[i].getForm();
1444 assert(Form && "Too many attributes for DIE (check abbreviation)");
1446 if (Asm->isVerbose()) {
1447 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1448 if (Attr == dwarf::DW_AT_accessibility)
1449 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1450 cast<DIEInteger>(Values[i])->getValue()));
1453 // Emit an attribute using the defined form.
1454 Values[i]->EmitValue(Asm, Form);
1457 // Emit the DIE children if any.
1458 if (Abbrev.hasChildren()) {
1459 for (auto &Child : Die.getChildren())
1462 Asm->OutStreamer.AddComment("End Of Children Mark");
1467 // Emit the debug info section.
1468 void DwarfDebug::emitDebugInfo() {
1469 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1471 Holder.emitUnits(DwarfAbbrevSectionSym);
1474 // Emit the abbreviation section.
1475 void DwarfDebug::emitAbbreviations() {
1476 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1478 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1481 // Emit the last address of the section and the end of the line matrix.
1482 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1483 // Define last address of section.
1484 Asm->OutStreamer.AddComment("Extended Op");
1487 Asm->OutStreamer.AddComment("Op size");
1488 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1489 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1490 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1492 Asm->OutStreamer.AddComment("Section end label");
1494 Asm->OutStreamer.EmitSymbolValue(
1495 Asm->GetTempSymbol("section_end", SectionEnd),
1496 Asm->getDataLayout().getPointerSize());
1498 // Mark end of matrix.
1499 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1505 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1506 StringRef TableName, StringRef SymName) {
1507 Accel.FinalizeTable(Asm, TableName);
1508 Asm->OutStreamer.SwitchSection(Section);
1509 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1510 Asm->OutStreamer.EmitLabel(SectionBegin);
1512 // Emit the full data.
1513 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1516 // Emit visible names into a hashed accelerator table section.
1517 void DwarfDebug::emitAccelNames() {
1518 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1519 "Names", "names_begin");
1522 // Emit objective C classes and categories into a hashed accelerator table
1524 void DwarfDebug::emitAccelObjC() {
1525 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1526 "ObjC", "objc_begin");
1529 // Emit namespace dies into a hashed accelerator table.
1530 void DwarfDebug::emitAccelNamespaces() {
1531 emitAccel(AccelNamespace,
1532 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1533 "namespac", "namespac_begin");
1536 // Emit type dies into a hashed accelerator table.
1537 void DwarfDebug::emitAccelTypes() {
1538 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1539 "types", "types_begin");
1542 // Public name handling.
1543 // The format for the various pubnames:
1545 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1546 // for the DIE that is named.
1548 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1549 // into the CU and the index value is computed according to the type of value
1550 // for the DIE that is named.
1552 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1553 // it's the offset within the debug_info/debug_types dwo section, however, the
1554 // reference in the pubname header doesn't change.
1556 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1557 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1559 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1561 // We could have a specification DIE that has our most of our knowledge,
1562 // look for that now.
1563 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1565 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1566 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1567 Linkage = dwarf::GIEL_EXTERNAL;
1568 } else if (Die->findAttribute(dwarf::DW_AT_external))
1569 Linkage = dwarf::GIEL_EXTERNAL;
1571 switch (Die->getTag()) {
1572 case dwarf::DW_TAG_class_type:
1573 case dwarf::DW_TAG_structure_type:
1574 case dwarf::DW_TAG_union_type:
1575 case dwarf::DW_TAG_enumeration_type:
1576 return dwarf::PubIndexEntryDescriptor(
1577 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1578 ? dwarf::GIEL_STATIC
1579 : dwarf::GIEL_EXTERNAL);
1580 case dwarf::DW_TAG_typedef:
1581 case dwarf::DW_TAG_base_type:
1582 case dwarf::DW_TAG_subrange_type:
1583 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1584 case dwarf::DW_TAG_namespace:
1585 return dwarf::GIEK_TYPE;
1586 case dwarf::DW_TAG_subprogram:
1587 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1588 case dwarf::DW_TAG_constant:
1589 case dwarf::DW_TAG_variable:
1590 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1591 case dwarf::DW_TAG_enumerator:
1592 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1593 dwarf::GIEL_STATIC);
1595 return dwarf::GIEK_NONE;
1599 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1601 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1602 const MCSection *PSec =
1603 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1604 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1606 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1609 void DwarfDebug::emitDebugPubSection(
1610 bool GnuStyle, const MCSection *PSec, StringRef Name,
1611 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1612 for (const auto &NU : CUMap) {
1613 DwarfCompileUnit *TheU = NU.second;
1615 const auto &Globals = (TheU->*Accessor)();
1617 if (Globals.empty())
1620 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1622 unsigned ID = TheU->getUniqueID();
1624 // Start the dwarf pubnames section.
1625 Asm->OutStreamer.SwitchSection(PSec);
1628 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1629 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1630 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1631 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1633 Asm->OutStreamer.EmitLabel(BeginLabel);
1635 Asm->OutStreamer.AddComment("DWARF Version");
1636 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1638 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1639 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1641 Asm->OutStreamer.AddComment("Compilation Unit Length");
1642 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1644 // Emit the pubnames for this compilation unit.
1645 for (const auto &GI : Globals) {
1646 const char *Name = GI.getKeyData();
1647 const DIE *Entity = GI.second;
1649 Asm->OutStreamer.AddComment("DIE offset");
1650 Asm->EmitInt32(Entity->getOffset());
1653 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1654 Asm->OutStreamer.AddComment(
1655 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1656 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1657 Asm->EmitInt8(Desc.toBits());
1660 Asm->OutStreamer.AddComment("External Name");
1661 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1664 Asm->OutStreamer.AddComment("End Mark");
1666 Asm->OutStreamer.EmitLabel(EndLabel);
1670 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1671 const MCSection *PSec =
1672 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1673 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1675 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1678 // Emit visible names into a debug str section.
1679 void DwarfDebug::emitDebugStr() {
1680 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1681 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1684 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1685 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1686 const DITypeIdentifierMap &Map,
1687 ArrayRef<DebugLocEntry::Value> Values) {
1688 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1689 return P.isVariablePiece();
1690 }) && "all values are expected to be pieces");
1691 assert(std::is_sorted(Values.begin(), Values.end()) &&
1692 "pieces are expected to be sorted");
1694 unsigned Offset = 0;
1695 for (auto Piece : Values) {
1696 DIExpression Expr = Piece.getExpression();
1697 unsigned PieceOffset = Expr.getPieceOffset();
1698 unsigned PieceSize = Expr.getPieceSize();
1699 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1700 if (Offset < PieceOffset) {
1701 // The DWARF spec seriously mandates pieces with no locations for gaps.
1702 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1703 Offset += PieceOffset-Offset;
1706 Offset += PieceSize;
1708 const unsigned SizeOfByte = 8;
1710 DIVariable Var = Piece.getVariable();
1711 assert(!Var.isIndirect() && "indirect address for piece");
1712 unsigned VarSize = Var.getSizeInBits(Map);
1713 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1714 && "piece is larger than or outside of variable");
1715 assert(PieceSize*SizeOfByte != VarSize
1716 && "piece covers entire variable");
1718 if (Piece.isLocation() && Piece.getLoc().isReg())
1719 Asm->EmitDwarfRegOpPiece(Streamer,
1721 PieceSize*SizeOfByte);
1723 emitDebugLocValue(Streamer, Piece);
1724 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1730 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1731 const DebugLocEntry &Entry) {
1732 const DebugLocEntry::Value Value = Entry.getValues()[0];
1733 if (Value.isVariablePiece())
1734 // Emit all pieces that belong to the same variable and range.
1735 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1737 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1738 emitDebugLocValue(Streamer, Value);
1741 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1742 const DebugLocEntry::Value &Value) {
1743 DIVariable DV = Value.getVariable();
1745 if (Value.isInt()) {
1746 DIBasicType BTy(resolve(DV.getType()));
1747 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1748 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1749 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1750 Streamer.EmitSLEB128(Value.getInt());
1752 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1753 Streamer.EmitULEB128(Value.getInt());
1755 } else if (Value.isLocation()) {
1756 MachineLocation Loc = Value.getLoc();
1757 DIExpression Expr = Value.getExpression();
1760 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1762 // Complex address entry.
1763 unsigned N = Expr.getNumElements();
1765 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1766 if (Loc.getOffset()) {
1768 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1769 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1770 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1771 Streamer.EmitSLEB128(Expr.getElement(1));
1773 // If first address element is OpPlus then emit
1774 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1775 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1776 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1780 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1783 // Emit remaining complex address elements.
1784 for (; i < N; ++i) {
1785 uint64_t Element = Expr.getElement(i);
1786 if (Element == dwarf::DW_OP_plus) {
1787 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1788 Streamer.EmitULEB128(Expr.getElement(++i));
1789 } else if (Element == dwarf::DW_OP_deref) {
1791 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1792 } else if (Element == dwarf::DW_OP_piece) {
1794 // handled in emitDebugLocEntry.
1796 llvm_unreachable("unknown Opcode found in complex address");
1800 // else ... ignore constant fp. There is not any good way to
1801 // to represent them here in dwarf.
1805 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1806 Asm->OutStreamer.AddComment("Loc expr size");
1807 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1808 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1809 Asm->EmitLabelDifference(end, begin, 2);
1810 Asm->OutStreamer.EmitLabel(begin);
1812 APByteStreamer Streamer(*Asm);
1813 emitDebugLocEntry(Streamer, Entry);
1815 Asm->OutStreamer.EmitLabel(end);
1818 // Emit locations into the debug loc section.
1819 void DwarfDebug::emitDebugLoc() {
1820 // Start the dwarf loc section.
1821 Asm->OutStreamer.SwitchSection(
1822 Asm->getObjFileLowering().getDwarfLocSection());
1823 unsigned char Size = Asm->getDataLayout().getPointerSize();
1824 for (const auto &DebugLoc : DotDebugLocEntries) {
1825 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1826 const DwarfCompileUnit *CU = DebugLoc.CU;
1827 assert(!CU->getRanges().empty());
1828 for (const auto &Entry : DebugLoc.List) {
1829 // Set up the range. This range is relative to the entry point of the
1830 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1831 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1832 if (CU->getRanges().size() == 1) {
1833 // Grab the begin symbol from the first range as our base.
1834 const MCSymbol *Base = CU->getRanges()[0].getStart();
1835 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1836 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1838 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1839 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1842 emitDebugLocEntryLocation(Entry);
1844 Asm->OutStreamer.EmitIntValue(0, Size);
1845 Asm->OutStreamer.EmitIntValue(0, Size);
1849 void DwarfDebug::emitDebugLocDWO() {
1850 Asm->OutStreamer.SwitchSection(
1851 Asm->getObjFileLowering().getDwarfLocDWOSection());
1852 for (const auto &DebugLoc : DotDebugLocEntries) {
1853 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1854 for (const auto &Entry : DebugLoc.List) {
1855 // Just always use start_length for now - at least that's one address
1856 // rather than two. We could get fancier and try to, say, reuse an
1857 // address we know we've emitted elsewhere (the start of the function?
1858 // The start of the CU or CU subrange that encloses this range?)
1859 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1860 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1861 Asm->EmitULEB128(idx);
1862 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1864 emitDebugLocEntryLocation(Entry);
1866 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1871 const MCSymbol *Start, *End;
1874 // Emit a debug aranges section, containing a CU lookup for any
1875 // address we can tie back to a CU.
1876 void DwarfDebug::emitDebugARanges() {
1877 // Start the dwarf aranges section.
1878 Asm->OutStreamer.SwitchSection(
1879 Asm->getObjFileLowering().getDwarfARangesSection());
1881 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1885 // Build a list of sections used.
1886 std::vector<const MCSection *> Sections;
1887 for (const auto &it : SectionMap) {
1888 const MCSection *Section = it.first;
1889 Sections.push_back(Section);
1892 // Sort the sections into order.
1893 // This is only done to ensure consistent output order across different runs.
1894 std::sort(Sections.begin(), Sections.end(), SectionSort);
1896 // Build a set of address spans, sorted by CU.
1897 for (const MCSection *Section : Sections) {
1898 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1899 if (List.size() < 2)
1902 // Sort the symbols by offset within the section.
1903 std::sort(List.begin(), List.end(),
1904 [&](const SymbolCU &A, const SymbolCU &B) {
1905 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1906 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1908 // Symbols with no order assigned should be placed at the end.
1909 // (e.g. section end labels)
1917 // If we have no section (e.g. common), just write out
1918 // individual spans for each symbol.
1920 for (const SymbolCU &Cur : List) {
1922 Span.Start = Cur.Sym;
1925 Spans[Cur.CU].push_back(Span);
1928 // Build spans between each label.
1929 const MCSymbol *StartSym = List[0].Sym;
1930 for (size_t n = 1, e = List.size(); n < e; n++) {
1931 const SymbolCU &Prev = List[n - 1];
1932 const SymbolCU &Cur = List[n];
1934 // Try and build the longest span we can within the same CU.
1935 if (Cur.CU != Prev.CU) {
1937 Span.Start = StartSym;
1939 Spans[Prev.CU].push_back(Span);
1946 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1948 // Build a list of CUs used.
1949 std::vector<DwarfCompileUnit *> CUs;
1950 for (const auto &it : Spans) {
1951 DwarfCompileUnit *CU = it.first;
1955 // Sort the CU list (again, to ensure consistent output order).
1956 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1957 return A->getUniqueID() < B->getUniqueID();
1960 // Emit an arange table for each CU we used.
1961 for (DwarfCompileUnit *CU : CUs) {
1962 std::vector<ArangeSpan> &List = Spans[CU];
1964 // Emit size of content not including length itself.
1965 unsigned ContentSize =
1966 sizeof(int16_t) + // DWARF ARange version number
1967 sizeof(int32_t) + // Offset of CU in the .debug_info section
1968 sizeof(int8_t) + // Pointer Size (in bytes)
1969 sizeof(int8_t); // Segment Size (in bytes)
1971 unsigned TupleSize = PtrSize * 2;
1973 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1975 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1977 ContentSize += Padding;
1978 ContentSize += (List.size() + 1) * TupleSize;
1980 // For each compile unit, write the list of spans it covers.
1981 Asm->OutStreamer.AddComment("Length of ARange Set");
1982 Asm->EmitInt32(ContentSize);
1983 Asm->OutStreamer.AddComment("DWARF Arange version number");
1984 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1985 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1986 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1987 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1988 Asm->EmitInt8(PtrSize);
1989 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1992 Asm->OutStreamer.EmitFill(Padding, 0xff);
1994 for (const ArangeSpan &Span : List) {
1995 Asm->EmitLabelReference(Span.Start, PtrSize);
1997 // Calculate the size as being from the span start to it's end.
1999 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2001 // For symbols without an end marker (e.g. common), we
2002 // write a single arange entry containing just that one symbol.
2003 uint64_t Size = SymSize[Span.Start];
2007 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2011 Asm->OutStreamer.AddComment("ARange terminator");
2012 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2013 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2017 // Emit visible names into a debug ranges section.
2018 void DwarfDebug::emitDebugRanges() {
2019 // Start the dwarf ranges section.
2020 Asm->OutStreamer.SwitchSection(
2021 Asm->getObjFileLowering().getDwarfRangesSection());
2023 // Size for our labels.
2024 unsigned char Size = Asm->getDataLayout().getPointerSize();
2026 // Grab the specific ranges for the compile units in the module.
2027 for (const auto &I : CUMap) {
2028 DwarfCompileUnit *TheCU = I.second;
2030 // Iterate over the misc ranges for the compile units in the module.
2031 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2032 // Emit our symbol so we can find the beginning of the range.
2033 Asm->OutStreamer.EmitLabel(List.getSym());
2035 for (const RangeSpan &Range : List.getRanges()) {
2036 const MCSymbol *Begin = Range.getStart();
2037 const MCSymbol *End = Range.getEnd();
2038 assert(Begin && "Range without a begin symbol?");
2039 assert(End && "Range without an end symbol?");
2040 if (TheCU->getRanges().size() == 1) {
2041 // Grab the begin symbol from the first range as our base.
2042 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2043 Asm->EmitLabelDifference(Begin, Base, Size);
2044 Asm->EmitLabelDifference(End, Base, Size);
2046 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2047 Asm->OutStreamer.EmitSymbolValue(End, Size);
2051 // And terminate the list with two 0 values.
2052 Asm->OutStreamer.EmitIntValue(0, Size);
2053 Asm->OutStreamer.EmitIntValue(0, Size);
2056 // Now emit a range for the CU itself.
2057 if (TheCU->getRanges().size() > 1) {
2058 Asm->OutStreamer.EmitLabel(
2059 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2060 for (const RangeSpan &Range : TheCU->getRanges()) {
2061 const MCSymbol *Begin = Range.getStart();
2062 const MCSymbol *End = Range.getEnd();
2063 assert(Begin && "Range without a begin symbol?");
2064 assert(End && "Range without an end symbol?");
2065 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2066 Asm->OutStreamer.EmitSymbolValue(End, Size);
2068 // And terminate the list with two 0 values.
2069 Asm->OutStreamer.EmitIntValue(0, Size);
2070 Asm->OutStreamer.EmitIntValue(0, Size);
2075 // DWARF5 Experimental Separate Dwarf emitters.
2077 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2078 std::unique_ptr<DwarfUnit> NewU) {
2079 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2080 U.getCUNode().getSplitDebugFilename());
2082 if (!CompilationDir.empty())
2083 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2085 addGnuPubAttributes(*NewU, Die);
2087 SkeletonHolder.addUnit(std::move(NewU));
2090 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2091 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2092 // DW_AT_addr_base, DW_AT_ranges_base.
2093 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2095 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2096 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2097 DwarfCompileUnit &NewCU = *OwnedUnit;
2098 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2099 DwarfInfoSectionSym);
2101 NewCU.initStmtList(DwarfLineSectionSym);
2103 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2108 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2109 // compile units that would normally be in debug_info.
2110 void DwarfDebug::emitDebugInfoDWO() {
2111 assert(useSplitDwarf() && "No split dwarf debug info?");
2112 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2113 // emit relocations into the dwo file.
2114 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2117 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2118 // abbreviations for the .debug_info.dwo section.
2119 void DwarfDebug::emitDebugAbbrevDWO() {
2120 assert(useSplitDwarf() && "No split dwarf?");
2121 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2124 void DwarfDebug::emitDebugLineDWO() {
2125 assert(useSplitDwarf() && "No split dwarf?");
2126 Asm->OutStreamer.SwitchSection(
2127 Asm->getObjFileLowering().getDwarfLineDWOSection());
2128 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2131 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2132 // string section and is identical in format to traditional .debug_str
2134 void DwarfDebug::emitDebugStrDWO() {
2135 assert(useSplitDwarf() && "No split dwarf?");
2136 const MCSection *OffSec =
2137 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2138 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2142 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2143 if (!useSplitDwarf())
2146 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2147 return &SplitTypeUnitFileTable;
2150 static uint64_t makeTypeSignature(StringRef Identifier) {
2152 Hash.update(Identifier);
2153 // ... take the least significant 8 bytes and return those. Our MD5
2154 // implementation always returns its results in little endian, swap bytes
2156 MD5::MD5Result Result;
2158 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2161 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2162 StringRef Identifier, DIE &RefDie,
2163 DICompositeType CTy) {
2164 // Fast path if we're building some type units and one has already used the
2165 // address pool we know we're going to throw away all this work anyway, so
2166 // don't bother building dependent types.
2167 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2170 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2172 CU.addDIETypeSignature(RefDie, *TU);
2176 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2177 AddrPool.resetUsedFlag();
2179 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2180 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2181 this, &InfoHolder, getDwoLineTable(CU));
2182 DwarfTypeUnit &NewTU = *OwnedUnit;
2183 DIE &UnitDie = NewTU.getUnitDie();
2185 TypeUnitsUnderConstruction.push_back(
2186 std::make_pair(std::move(OwnedUnit), CTy));
2188 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2191 uint64_t Signature = makeTypeSignature(Identifier);
2192 NewTU.setTypeSignature(Signature);
2194 if (useSplitDwarf())
2195 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2196 DwarfTypesDWOSectionSym);
2198 CU.applyStmtList(UnitDie);
2200 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2203 NewTU.setType(NewTU.createTypeDIE(CTy));
2206 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2207 TypeUnitsUnderConstruction.clear();
2209 // Types referencing entries in the address table cannot be placed in type
2211 if (AddrPool.hasBeenUsed()) {
2213 // Remove all the types built while building this type.
2214 // This is pessimistic as some of these types might not be dependent on
2215 // the type that used an address.
2216 for (const auto &TU : TypeUnitsToAdd)
2217 DwarfTypeUnits.erase(TU.second);
2219 // Construct this type in the CU directly.
2220 // This is inefficient because all the dependent types will be rebuilt
2221 // from scratch, including building them in type units, discovering that
2222 // they depend on addresses, throwing them out and rebuilding them.
2223 CU.constructTypeDIE(RefDie, CTy);
2227 // If the type wasn't dependent on fission addresses, finish adding the type
2228 // and all its dependent types.
2229 for (auto &TU : TypeUnitsToAdd)
2230 InfoHolder.addUnit(std::move(TU.first));
2232 CU.addDIETypeSignature(RefDie, NewTU);
2235 // Accelerator table mutators - add each name along with its companion
2236 // DIE to the proper table while ensuring that the name that we're going
2237 // to reference is in the string table. We do this since the names we
2238 // add may not only be identical to the names in the DIE.
2239 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2240 if (!useDwarfAccelTables())
2242 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2246 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2247 if (!useDwarfAccelTables())
2249 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2253 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2254 if (!useDwarfAccelTables())
2256 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2260 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2261 if (!useDwarfAccelTables())
2263 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),