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.addScopeVariable(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 InfoHolder.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 InfoHolder.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 InfoHolder.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 // Gather and emit post-function debug information.
1257 void DwarfDebug::endFunction(const MachineFunction *MF) {
1258 assert(CurFn == MF &&
1259 "endFunction should be called with the same function as beginFunction");
1261 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1262 !FunctionDIs.count(MF->getFunction())) {
1263 // If we don't have a lexical scope for this function then there will
1264 // be a hole in the range information. Keep note of this by setting the
1265 // previously used section to nullptr.
1271 // Define end label for subprogram.
1272 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1273 // Assumes in correct section after the entry point.
1274 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1276 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1277 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1279 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1280 DISubprogram SP(FnScope->getScopeNode());
1281 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1283 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1284 collectVariableInfo(TheCU, SP, ProcessedVars);
1286 // Add the range of this function to the list of ranges for the CU.
1287 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1289 // Under -gmlt, skip building the subprogram if there are no inlined
1290 // subroutines inside it.
1291 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1292 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1293 assert(ScopeVariables.empty());
1294 assert(DbgValues.empty());
1295 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1296 // by a -gmlt CU. Add a test and remove this assertion.
1297 assert(AbstractVariables.empty());
1298 LabelsBeforeInsn.clear();
1299 LabelsAfterInsn.clear();
1300 PrevLabel = nullptr;
1306 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1308 // Construct abstract scopes.
1309 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1310 DISubprogram SP(AScope->getScopeNode());
1311 assert(SP.isSubprogram());
1312 // Collect info for variables that were optimized out.
1313 DIArray Variables = SP.getVariables();
1314 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1315 DIVariable DV(Variables.getElement(i));
1316 assert(DV && DV.isVariable());
1317 if (!ProcessedVars.insert(DV))
1319 ensureAbstractVariableIsCreated(DV, DV.getContext());
1320 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1321 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1323 constructAbstractSubprogramScopeDIE(AScope);
1326 TheCU.constructSubprogramScopeDIE(FnScope);
1329 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1330 // DbgVariables except those that are also in AbstractVariables (since they
1331 // can be used cross-function)
1332 ScopeVariables.clear();
1334 LabelsBeforeInsn.clear();
1335 LabelsAfterInsn.clear();
1336 PrevLabel = nullptr;
1340 // Register a source line with debug info. Returns the unique label that was
1341 // emitted and which provides correspondence to the source line list.
1342 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1347 unsigned Discriminator = 0;
1348 if (DIScope Scope = DIScope(S)) {
1349 assert(Scope.isScope());
1350 Fn = Scope.getFilename();
1351 Dir = Scope.getDirectory();
1352 if (Scope.isLexicalBlockFile())
1353 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1355 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1356 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1357 .getOrCreateSourceID(Fn, Dir);
1359 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1363 //===----------------------------------------------------------------------===//
1365 //===----------------------------------------------------------------------===//
1367 // Emit initial Dwarf sections with a label at the start of each one.
1368 void DwarfDebug::emitSectionLabels() {
1369 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1371 // Dwarf sections base addresses.
1372 DwarfInfoSectionSym =
1373 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1374 if (useSplitDwarf()) {
1375 DwarfInfoDWOSectionSym =
1376 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1377 DwarfTypesDWOSectionSym =
1378 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1380 DwarfAbbrevSectionSym =
1381 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1382 if (useSplitDwarf())
1383 DwarfAbbrevDWOSectionSym = emitSectionSym(
1384 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1385 if (GenerateARangeSection)
1386 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1388 DwarfLineSectionSym =
1389 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1390 if (GenerateGnuPubSections) {
1391 DwarfGnuPubNamesSectionSym =
1392 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1393 DwarfGnuPubTypesSectionSym =
1394 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1395 } else if (HasDwarfPubSections) {
1396 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1397 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1400 DwarfStrSectionSym =
1401 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1402 if (useSplitDwarf()) {
1403 DwarfStrDWOSectionSym =
1404 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1405 DwarfAddrSectionSym =
1406 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1407 DwarfDebugLocSectionSym =
1408 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1410 DwarfDebugLocSectionSym =
1411 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1412 DwarfDebugRangeSectionSym =
1413 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1416 // Recursively emits a debug information entry.
1417 void DwarfDebug::emitDIE(DIE &Die) {
1418 // Get the abbreviation for this DIE.
1419 const DIEAbbrev &Abbrev = Die.getAbbrev();
1421 // Emit the code (index) for the abbreviation.
1422 if (Asm->isVerbose())
1423 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1424 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1425 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1426 dwarf::TagString(Abbrev.getTag()));
1427 Asm->EmitULEB128(Abbrev.getNumber());
1429 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1430 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1432 // Emit the DIE attribute values.
1433 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1434 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1435 dwarf::Form Form = AbbrevData[i].getForm();
1436 assert(Form && "Too many attributes for DIE (check abbreviation)");
1438 if (Asm->isVerbose()) {
1439 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1440 if (Attr == dwarf::DW_AT_accessibility)
1441 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1442 cast<DIEInteger>(Values[i])->getValue()));
1445 // Emit an attribute using the defined form.
1446 Values[i]->EmitValue(Asm, Form);
1449 // Emit the DIE children if any.
1450 if (Abbrev.hasChildren()) {
1451 for (auto &Child : Die.getChildren())
1454 Asm->OutStreamer.AddComment("End Of Children Mark");
1459 // Emit the debug info section.
1460 void DwarfDebug::emitDebugInfo() {
1461 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1463 Holder.emitUnits(DwarfAbbrevSectionSym);
1466 // Emit the abbreviation section.
1467 void DwarfDebug::emitAbbreviations() {
1468 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1470 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1473 // Emit the last address of the section and the end of the line matrix.
1474 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1475 // Define last address of section.
1476 Asm->OutStreamer.AddComment("Extended Op");
1479 Asm->OutStreamer.AddComment("Op size");
1480 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1481 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1482 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1484 Asm->OutStreamer.AddComment("Section end label");
1486 Asm->OutStreamer.EmitSymbolValue(
1487 Asm->GetTempSymbol("section_end", SectionEnd),
1488 Asm->getDataLayout().getPointerSize());
1490 // Mark end of matrix.
1491 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1497 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1498 StringRef TableName, StringRef SymName) {
1499 Accel.FinalizeTable(Asm, TableName);
1500 Asm->OutStreamer.SwitchSection(Section);
1501 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1502 Asm->OutStreamer.EmitLabel(SectionBegin);
1504 // Emit the full data.
1505 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1508 // Emit visible names into a hashed accelerator table section.
1509 void DwarfDebug::emitAccelNames() {
1510 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1511 "Names", "names_begin");
1514 // Emit objective C classes and categories into a hashed accelerator table
1516 void DwarfDebug::emitAccelObjC() {
1517 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1518 "ObjC", "objc_begin");
1521 // Emit namespace dies into a hashed accelerator table.
1522 void DwarfDebug::emitAccelNamespaces() {
1523 emitAccel(AccelNamespace,
1524 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1525 "namespac", "namespac_begin");
1528 // Emit type dies into a hashed accelerator table.
1529 void DwarfDebug::emitAccelTypes() {
1530 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1531 "types", "types_begin");
1534 // Public name handling.
1535 // The format for the various pubnames:
1537 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1538 // for the DIE that is named.
1540 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1541 // into the CU and the index value is computed according to the type of value
1542 // for the DIE that is named.
1544 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1545 // it's the offset within the debug_info/debug_types dwo section, however, the
1546 // reference in the pubname header doesn't change.
1548 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1549 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1551 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1553 // We could have a specification DIE that has our most of our knowledge,
1554 // look for that now.
1555 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1557 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1558 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1559 Linkage = dwarf::GIEL_EXTERNAL;
1560 } else if (Die->findAttribute(dwarf::DW_AT_external))
1561 Linkage = dwarf::GIEL_EXTERNAL;
1563 switch (Die->getTag()) {
1564 case dwarf::DW_TAG_class_type:
1565 case dwarf::DW_TAG_structure_type:
1566 case dwarf::DW_TAG_union_type:
1567 case dwarf::DW_TAG_enumeration_type:
1568 return dwarf::PubIndexEntryDescriptor(
1569 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1570 ? dwarf::GIEL_STATIC
1571 : dwarf::GIEL_EXTERNAL);
1572 case dwarf::DW_TAG_typedef:
1573 case dwarf::DW_TAG_base_type:
1574 case dwarf::DW_TAG_subrange_type:
1575 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1576 case dwarf::DW_TAG_namespace:
1577 return dwarf::GIEK_TYPE;
1578 case dwarf::DW_TAG_subprogram:
1579 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1580 case dwarf::DW_TAG_constant:
1581 case dwarf::DW_TAG_variable:
1582 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1583 case dwarf::DW_TAG_enumerator:
1584 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1585 dwarf::GIEL_STATIC);
1587 return dwarf::GIEK_NONE;
1591 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1593 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1594 const MCSection *PSec =
1595 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1596 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1598 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1601 void DwarfDebug::emitDebugPubSection(
1602 bool GnuStyle, const MCSection *PSec, StringRef Name,
1603 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1604 for (const auto &NU : CUMap) {
1605 DwarfCompileUnit *TheU = NU.second;
1607 const auto &Globals = (TheU->*Accessor)();
1609 if (Globals.empty())
1612 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1614 unsigned ID = TheU->getUniqueID();
1616 // Start the dwarf pubnames section.
1617 Asm->OutStreamer.SwitchSection(PSec);
1620 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1621 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1622 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1623 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1625 Asm->OutStreamer.EmitLabel(BeginLabel);
1627 Asm->OutStreamer.AddComment("DWARF Version");
1628 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1630 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1631 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1633 Asm->OutStreamer.AddComment("Compilation Unit Length");
1634 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1636 // Emit the pubnames for this compilation unit.
1637 for (const auto &GI : Globals) {
1638 const char *Name = GI.getKeyData();
1639 const DIE *Entity = GI.second;
1641 Asm->OutStreamer.AddComment("DIE offset");
1642 Asm->EmitInt32(Entity->getOffset());
1645 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1646 Asm->OutStreamer.AddComment(
1647 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1648 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1649 Asm->EmitInt8(Desc.toBits());
1652 Asm->OutStreamer.AddComment("External Name");
1653 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1656 Asm->OutStreamer.AddComment("End Mark");
1658 Asm->OutStreamer.EmitLabel(EndLabel);
1662 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1663 const MCSection *PSec =
1664 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1665 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1667 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1670 // Emit visible names into a debug str section.
1671 void DwarfDebug::emitDebugStr() {
1672 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1673 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1676 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1677 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1678 const DITypeIdentifierMap &Map,
1679 ArrayRef<DebugLocEntry::Value> Values) {
1680 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1681 return P.isVariablePiece();
1682 }) && "all values are expected to be pieces");
1683 assert(std::is_sorted(Values.begin(), Values.end()) &&
1684 "pieces are expected to be sorted");
1686 unsigned Offset = 0;
1687 for (auto Piece : Values) {
1688 DIExpression Expr = Piece.getExpression();
1689 unsigned PieceOffset = Expr.getPieceOffset();
1690 unsigned PieceSize = Expr.getPieceSize();
1691 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1692 if (Offset < PieceOffset) {
1693 // The DWARF spec seriously mandates pieces with no locations for gaps.
1694 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1695 Offset += PieceOffset-Offset;
1698 Offset += PieceSize;
1700 const unsigned SizeOfByte = 8;
1702 DIVariable Var = Piece.getVariable();
1703 assert(!Var.isIndirect() && "indirect address for piece");
1704 unsigned VarSize = Var.getSizeInBits(Map);
1705 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1706 && "piece is larger than or outside of variable");
1707 assert(PieceSize*SizeOfByte != VarSize
1708 && "piece covers entire variable");
1710 if (Piece.isLocation() && Piece.getLoc().isReg())
1711 Asm->EmitDwarfRegOpPiece(Streamer,
1713 PieceSize*SizeOfByte);
1715 emitDebugLocValue(Streamer, Piece);
1716 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1722 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1723 const DebugLocEntry &Entry) {
1724 const DebugLocEntry::Value Value = Entry.getValues()[0];
1725 if (Value.isVariablePiece())
1726 // Emit all pieces that belong to the same variable and range.
1727 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1729 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1730 emitDebugLocValue(Streamer, Value);
1733 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1734 const DebugLocEntry::Value &Value) {
1735 DIVariable DV = Value.getVariable();
1737 if (Value.isInt()) {
1738 DIBasicType BTy(resolve(DV.getType()));
1739 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1740 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1741 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1742 Streamer.EmitSLEB128(Value.getInt());
1744 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1745 Streamer.EmitULEB128(Value.getInt());
1747 } else if (Value.isLocation()) {
1748 MachineLocation Loc = Value.getLoc();
1749 DIExpression Expr = Value.getExpression();
1752 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1754 // Complex address entry.
1755 unsigned N = Expr.getNumElements();
1757 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1758 if (Loc.getOffset()) {
1760 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1761 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1762 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1763 Streamer.EmitSLEB128(Expr.getElement(1));
1765 // If first address element is OpPlus then emit
1766 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1767 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1768 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1772 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1775 // Emit remaining complex address elements.
1776 for (; i < N; ++i) {
1777 uint64_t Element = Expr.getElement(i);
1778 if (Element == dwarf::DW_OP_plus) {
1779 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1780 Streamer.EmitULEB128(Expr.getElement(++i));
1781 } else if (Element == dwarf::DW_OP_deref) {
1783 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1784 } else if (Element == dwarf::DW_OP_piece) {
1786 // handled in emitDebugLocEntry.
1788 llvm_unreachable("unknown Opcode found in complex address");
1792 // else ... ignore constant fp. There is not any good way to
1793 // to represent them here in dwarf.
1797 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1798 Asm->OutStreamer.AddComment("Loc expr size");
1799 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1800 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1801 Asm->EmitLabelDifference(end, begin, 2);
1802 Asm->OutStreamer.EmitLabel(begin);
1804 APByteStreamer Streamer(*Asm);
1805 emitDebugLocEntry(Streamer, Entry);
1807 Asm->OutStreamer.EmitLabel(end);
1810 // Emit locations into the debug loc section.
1811 void DwarfDebug::emitDebugLoc() {
1812 // Start the dwarf loc section.
1813 Asm->OutStreamer.SwitchSection(
1814 Asm->getObjFileLowering().getDwarfLocSection());
1815 unsigned char Size = Asm->getDataLayout().getPointerSize();
1816 for (const auto &DebugLoc : DotDebugLocEntries) {
1817 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1818 const DwarfCompileUnit *CU = DebugLoc.CU;
1819 assert(!CU->getRanges().empty());
1820 for (const auto &Entry : DebugLoc.List) {
1821 // Set up the range. This range is relative to the entry point of the
1822 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1823 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1824 if (CU->getRanges().size() == 1) {
1825 // Grab the begin symbol from the first range as our base.
1826 const MCSymbol *Base = CU->getRanges()[0].getStart();
1827 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1828 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1830 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1831 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1834 emitDebugLocEntryLocation(Entry);
1836 Asm->OutStreamer.EmitIntValue(0, Size);
1837 Asm->OutStreamer.EmitIntValue(0, Size);
1841 void DwarfDebug::emitDebugLocDWO() {
1842 Asm->OutStreamer.SwitchSection(
1843 Asm->getObjFileLowering().getDwarfLocDWOSection());
1844 for (const auto &DebugLoc : DotDebugLocEntries) {
1845 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1846 for (const auto &Entry : DebugLoc.List) {
1847 // Just always use start_length for now - at least that's one address
1848 // rather than two. We could get fancier and try to, say, reuse an
1849 // address we know we've emitted elsewhere (the start of the function?
1850 // The start of the CU or CU subrange that encloses this range?)
1851 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1852 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1853 Asm->EmitULEB128(idx);
1854 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1856 emitDebugLocEntryLocation(Entry);
1858 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1863 const MCSymbol *Start, *End;
1866 // Emit a debug aranges section, containing a CU lookup for any
1867 // address we can tie back to a CU.
1868 void DwarfDebug::emitDebugARanges() {
1869 // Start the dwarf aranges section.
1870 Asm->OutStreamer.SwitchSection(
1871 Asm->getObjFileLowering().getDwarfARangesSection());
1873 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1877 // Build a list of sections used.
1878 std::vector<const MCSection *> Sections;
1879 for (const auto &it : SectionMap) {
1880 const MCSection *Section = it.first;
1881 Sections.push_back(Section);
1884 // Sort the sections into order.
1885 // This is only done to ensure consistent output order across different runs.
1886 std::sort(Sections.begin(), Sections.end(), SectionSort);
1888 // Build a set of address spans, sorted by CU.
1889 for (const MCSection *Section : Sections) {
1890 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1891 if (List.size() < 2)
1894 // Sort the symbols by offset within the section.
1895 std::sort(List.begin(), List.end(),
1896 [&](const SymbolCU &A, const SymbolCU &B) {
1897 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1898 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1900 // Symbols with no order assigned should be placed at the end.
1901 // (e.g. section end labels)
1909 // If we have no section (e.g. common), just write out
1910 // individual spans for each symbol.
1912 for (const SymbolCU &Cur : List) {
1914 Span.Start = Cur.Sym;
1917 Spans[Cur.CU].push_back(Span);
1920 // Build spans between each label.
1921 const MCSymbol *StartSym = List[0].Sym;
1922 for (size_t n = 1, e = List.size(); n < e; n++) {
1923 const SymbolCU &Prev = List[n - 1];
1924 const SymbolCU &Cur = List[n];
1926 // Try and build the longest span we can within the same CU.
1927 if (Cur.CU != Prev.CU) {
1929 Span.Start = StartSym;
1931 Spans[Prev.CU].push_back(Span);
1938 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1940 // Build a list of CUs used.
1941 std::vector<DwarfCompileUnit *> CUs;
1942 for (const auto &it : Spans) {
1943 DwarfCompileUnit *CU = it.first;
1947 // Sort the CU list (again, to ensure consistent output order).
1948 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1949 return A->getUniqueID() < B->getUniqueID();
1952 // Emit an arange table for each CU we used.
1953 for (DwarfCompileUnit *CU : CUs) {
1954 std::vector<ArangeSpan> &List = Spans[CU];
1956 // Emit size of content not including length itself.
1957 unsigned ContentSize =
1958 sizeof(int16_t) + // DWARF ARange version number
1959 sizeof(int32_t) + // Offset of CU in the .debug_info section
1960 sizeof(int8_t) + // Pointer Size (in bytes)
1961 sizeof(int8_t); // Segment Size (in bytes)
1963 unsigned TupleSize = PtrSize * 2;
1965 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1967 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1969 ContentSize += Padding;
1970 ContentSize += (List.size() + 1) * TupleSize;
1972 // For each compile unit, write the list of spans it covers.
1973 Asm->OutStreamer.AddComment("Length of ARange Set");
1974 Asm->EmitInt32(ContentSize);
1975 Asm->OutStreamer.AddComment("DWARF Arange version number");
1976 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1977 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1978 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
1979 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1980 Asm->EmitInt8(PtrSize);
1981 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1984 Asm->OutStreamer.EmitFill(Padding, 0xff);
1986 for (const ArangeSpan &Span : List) {
1987 Asm->EmitLabelReference(Span.Start, PtrSize);
1989 // Calculate the size as being from the span start to it's end.
1991 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1993 // For symbols without an end marker (e.g. common), we
1994 // write a single arange entry containing just that one symbol.
1995 uint64_t Size = SymSize[Span.Start];
1999 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2003 Asm->OutStreamer.AddComment("ARange terminator");
2004 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2005 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2009 // Emit visible names into a debug ranges section.
2010 void DwarfDebug::emitDebugRanges() {
2011 // Start the dwarf ranges section.
2012 Asm->OutStreamer.SwitchSection(
2013 Asm->getObjFileLowering().getDwarfRangesSection());
2015 // Size for our labels.
2016 unsigned char Size = Asm->getDataLayout().getPointerSize();
2018 // Grab the specific ranges for the compile units in the module.
2019 for (const auto &I : CUMap) {
2020 DwarfCompileUnit *TheCU = I.second;
2022 // Iterate over the misc ranges for the compile units in the module.
2023 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2024 // Emit our symbol so we can find the beginning of the range.
2025 Asm->OutStreamer.EmitLabel(List.getSym());
2027 for (const RangeSpan &Range : List.getRanges()) {
2028 const MCSymbol *Begin = Range.getStart();
2029 const MCSymbol *End = Range.getEnd();
2030 assert(Begin && "Range without a begin symbol?");
2031 assert(End && "Range without an end symbol?");
2032 if (TheCU->getRanges().size() == 1) {
2033 // Grab the begin symbol from the first range as our base.
2034 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2035 Asm->EmitLabelDifference(Begin, Base, Size);
2036 Asm->EmitLabelDifference(End, Base, Size);
2038 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2039 Asm->OutStreamer.EmitSymbolValue(End, Size);
2043 // And terminate the list with two 0 values.
2044 Asm->OutStreamer.EmitIntValue(0, Size);
2045 Asm->OutStreamer.EmitIntValue(0, Size);
2048 // Now emit a range for the CU itself.
2049 if (TheCU->getRanges().size() > 1) {
2050 Asm->OutStreamer.EmitLabel(
2051 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2052 for (const RangeSpan &Range : TheCU->getRanges()) {
2053 const MCSymbol *Begin = Range.getStart();
2054 const MCSymbol *End = Range.getEnd();
2055 assert(Begin && "Range without a begin symbol?");
2056 assert(End && "Range without an end symbol?");
2057 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2058 Asm->OutStreamer.EmitSymbolValue(End, Size);
2060 // And terminate the list with two 0 values.
2061 Asm->OutStreamer.EmitIntValue(0, Size);
2062 Asm->OutStreamer.EmitIntValue(0, Size);
2067 // DWARF5 Experimental Separate Dwarf emitters.
2069 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2070 std::unique_ptr<DwarfUnit> NewU) {
2071 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2072 U.getCUNode().getSplitDebugFilename());
2074 if (!CompilationDir.empty())
2075 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2077 addGnuPubAttributes(*NewU, Die);
2079 SkeletonHolder.addUnit(std::move(NewU));
2082 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2083 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2084 // DW_AT_addr_base, DW_AT_ranges_base.
2085 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2087 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2088 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2089 DwarfCompileUnit &NewCU = *OwnedUnit;
2090 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2091 DwarfInfoSectionSym);
2093 NewCU.initStmtList(DwarfLineSectionSym);
2095 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2100 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2101 // compile units that would normally be in debug_info.
2102 void DwarfDebug::emitDebugInfoDWO() {
2103 assert(useSplitDwarf() && "No split dwarf debug info?");
2104 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2105 // emit relocations into the dwo file.
2106 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2109 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2110 // abbreviations for the .debug_info.dwo section.
2111 void DwarfDebug::emitDebugAbbrevDWO() {
2112 assert(useSplitDwarf() && "No split dwarf?");
2113 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2116 void DwarfDebug::emitDebugLineDWO() {
2117 assert(useSplitDwarf() && "No split dwarf?");
2118 Asm->OutStreamer.SwitchSection(
2119 Asm->getObjFileLowering().getDwarfLineDWOSection());
2120 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2123 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2124 // string section and is identical in format to traditional .debug_str
2126 void DwarfDebug::emitDebugStrDWO() {
2127 assert(useSplitDwarf() && "No split dwarf?");
2128 const MCSection *OffSec =
2129 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2130 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2134 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2135 if (!useSplitDwarf())
2138 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2139 return &SplitTypeUnitFileTable;
2142 static uint64_t makeTypeSignature(StringRef Identifier) {
2144 Hash.update(Identifier);
2145 // ... take the least significant 8 bytes and return those. Our MD5
2146 // implementation always returns its results in little endian, swap bytes
2148 MD5::MD5Result Result;
2150 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2153 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2154 StringRef Identifier, DIE &RefDie,
2155 DICompositeType CTy) {
2156 // Fast path if we're building some type units and one has already used the
2157 // address pool we know we're going to throw away all this work anyway, so
2158 // don't bother building dependent types.
2159 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2162 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2164 CU.addDIETypeSignature(RefDie, *TU);
2168 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2169 AddrPool.resetUsedFlag();
2171 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2172 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2173 this, &InfoHolder, getDwoLineTable(CU));
2174 DwarfTypeUnit &NewTU = *OwnedUnit;
2175 DIE &UnitDie = NewTU.getUnitDie();
2177 TypeUnitsUnderConstruction.push_back(
2178 std::make_pair(std::move(OwnedUnit), CTy));
2180 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2183 uint64_t Signature = makeTypeSignature(Identifier);
2184 NewTU.setTypeSignature(Signature);
2186 if (useSplitDwarf())
2187 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2188 DwarfTypesDWOSectionSym);
2190 CU.applyStmtList(UnitDie);
2192 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2195 NewTU.setType(NewTU.createTypeDIE(CTy));
2198 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2199 TypeUnitsUnderConstruction.clear();
2201 // Types referencing entries in the address table cannot be placed in type
2203 if (AddrPool.hasBeenUsed()) {
2205 // Remove all the types built while building this type.
2206 // This is pessimistic as some of these types might not be dependent on
2207 // the type that used an address.
2208 for (const auto &TU : TypeUnitsToAdd)
2209 DwarfTypeUnits.erase(TU.second);
2211 // Construct this type in the CU directly.
2212 // This is inefficient because all the dependent types will be rebuilt
2213 // from scratch, including building them in type units, discovering that
2214 // they depend on addresses, throwing them out and rebuilding them.
2215 CU.constructTypeDIE(RefDie, CTy);
2219 // If the type wasn't dependent on fission addresses, finish adding the type
2220 // and all its dependent types.
2221 for (auto &TU : TypeUnitsToAdd)
2222 InfoHolder.addUnit(std::move(TU.first));
2224 CU.addDIETypeSignature(RefDie, NewTU);
2227 // Accelerator table mutators - add each name along with its companion
2228 // DIE to the proper table while ensuring that the name that we're going
2229 // to reference is in the string table. We do this since the names we
2230 // add may not only be identical to the names in the DIE.
2231 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2232 if (!useDwarfAccelTables())
2234 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2238 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2239 if (!useDwarfAccelTables())
2241 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2245 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2246 if (!useDwarfAccelTables())
2248 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2252 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2253 if (!useDwarfAccelTables())
2255 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),