1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfDebug.h"
15 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.h"
18 #include "DwarfExpression.h"
19 #include "DwarfUnit.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/CodeGen/DIE.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) {
110 Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op)
111 : dwarf::OperationEncodingString(Op));
114 void DebugLocDwarfExpression::EmitSigned(int Value) {
115 BS.EmitSLEB128(Value, Twine(Value));
118 void DebugLocDwarfExpression::EmitUnsigned(unsigned Value) {
119 BS.EmitULEB128(Value, Twine(Value));
122 bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) {
123 // This information is not available while emitting .debug_loc entries.
127 //===----------------------------------------------------------------------===//
129 /// resolve - Look in the DwarfDebug map for the MDNode that
130 /// corresponds to the reference.
131 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
132 return DD->resolve(Ref);
135 bool DbgVariable::isBlockByrefVariable() const {
136 assert(Var.isVariable() && "Invalid complex DbgVariable!");
137 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
140 DIType DbgVariable::getType() const {
141 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
142 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
143 // addresses instead.
144 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
145 /* Byref variables, in Blocks, are declared by the programmer as
146 "SomeType VarName;", but the compiler creates a
147 __Block_byref_x_VarName struct, and gives the variable VarName
148 either the struct, or a pointer to the struct, as its type. This
149 is necessary for various behind-the-scenes things the compiler
150 needs to do with by-reference variables in blocks.
152 However, as far as the original *programmer* is concerned, the
153 variable should still have type 'SomeType', as originally declared.
155 The following function dives into the __Block_byref_x_VarName
156 struct to find the original type of the variable. This will be
157 passed back to the code generating the type for the Debug
158 Information Entry for the variable 'VarName'. 'VarName' will then
159 have the original type 'SomeType' in its debug information.
161 The original type 'SomeType' will be the type of the field named
162 'VarName' inside the __Block_byref_x_VarName struct.
164 NOTE: In order for this to not completely fail on the debugger
165 side, the Debug Information Entry for the variable VarName needs to
166 have a DW_AT_location that tells the debugger how to unwind through
167 the pointers and __Block_byref_x_VarName struct to find the actual
168 value of the variable. The function addBlockByrefType does this. */
170 uint16_t tag = Ty.getTag();
172 if (tag == dwarf::DW_TAG_pointer_type)
173 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
175 DIArray Elements = DICompositeType(subType).getElements();
176 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
177 DIDerivedType DT(Elements.getElement(i));
178 if (getName() == DT.getName())
179 return (resolve(DT.getTypeDerivedFrom()));
185 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
186 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
187 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
188 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
190 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
191 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
192 InfoHolder(A, "info_string", DIEValueAllocator),
193 UsedNonDefaultText(false),
194 SkeletonHolder(A, "skel_string", DIEValueAllocator),
195 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
196 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
197 dwarf::DW_FORM_data4)),
198 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
199 dwarf::DW_FORM_data4)),
200 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
201 dwarf::DW_FORM_data4)),
202 AccelTypes(TypeAtoms) {
204 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
205 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
206 DwarfLineSectionSym = nullptr;
207 DwarfAddrSectionSym = nullptr;
208 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
209 FunctionBeginSym = FunctionEndSym = nullptr;
213 // Turn on accelerator tables for Darwin by default, pubnames by
214 // default for non-Darwin, and handle split dwarf.
215 if (DwarfAccelTables == Default)
216 HasDwarfAccelTables = IsDarwin;
218 HasDwarfAccelTables = DwarfAccelTables == Enable;
220 if (SplitDwarf == Default)
221 HasSplitDwarf = false;
223 HasSplitDwarf = SplitDwarf == Enable;
225 if (DwarfPubSections == Default)
226 HasDwarfPubSections = !IsDarwin;
228 HasDwarfPubSections = DwarfPubSections == Enable;
230 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
231 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
232 : MMI->getModule()->getDwarfVersion();
234 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
237 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
242 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
243 DwarfDebug::~DwarfDebug() { }
245 // Switch to the specified MCSection and emit an assembler
246 // temporary label to it if SymbolStem is specified.
247 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
248 const char *SymbolStem = nullptr) {
249 Asm->OutStreamer.SwitchSection(Section);
253 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
254 Asm->OutStreamer.EmitLabel(TmpSym);
258 static bool isObjCClass(StringRef Name) {
259 return Name.startswith("+") || Name.startswith("-");
262 static bool hasObjCCategory(StringRef Name) {
263 if (!isObjCClass(Name))
266 return Name.find(") ") != StringRef::npos;
269 static void getObjCClassCategory(StringRef In, StringRef &Class,
270 StringRef &Category) {
271 if (!hasObjCCategory(In)) {
272 Class = In.slice(In.find('[') + 1, In.find(' '));
277 Class = In.slice(In.find('[') + 1, In.find('('));
278 Category = In.slice(In.find('[') + 1, In.find(' '));
282 static StringRef getObjCMethodName(StringRef In) {
283 return In.slice(In.find(' ') + 1, In.find(']'));
286 // Helper for sorting sections into a stable output order.
287 static bool SectionSort(const MCSection *A, const MCSection *B) {
288 std::string LA = (A ? A->getLabelBeginName() : "");
289 std::string LB = (B ? B->getLabelBeginName() : "");
293 // Add the various names to the Dwarf accelerator table names.
294 // TODO: Determine whether or not we should add names for programs
295 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
296 // is only slightly different than the lookup of non-standard ObjC names.
297 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
298 if (!SP.isDefinition())
300 addAccelName(SP.getName(), Die);
302 // If the linkage name is different than the name, go ahead and output
303 // that as well into the name table.
304 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
305 addAccelName(SP.getLinkageName(), Die);
307 // If this is an Objective-C selector name add it to the ObjC accelerator
309 if (isObjCClass(SP.getName())) {
310 StringRef Class, Category;
311 getObjCClassCategory(SP.getName(), Class, Category);
312 addAccelObjC(Class, Die);
314 addAccelObjC(Category, Die);
315 // Also add the base method name to the name table.
316 addAccelName(getObjCMethodName(SP.getName()), Die);
320 /// isSubprogramContext - Return true if Context is either a subprogram
321 /// or another context nested inside a subprogram.
322 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
325 DIDescriptor D(Context);
326 if (D.isSubprogram())
329 return isSubprogramContext(resolve(DIType(Context).getContext()));
333 /// Check whether we should create a DIE for the given Scope, return true
334 /// if we don't create a DIE (the corresponding DIE is null).
335 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
336 if (Scope->isAbstractScope())
339 // We don't create a DIE if there is no Range.
340 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
344 if (Ranges.size() > 1)
347 // We don't create a DIE if we have a single Range and the end label
349 return !getLabelAfterInsn(Ranges.front().second);
352 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
354 if (auto *SkelCU = CU.getSkeleton())
358 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
359 assert(Scope && Scope->getScopeNode());
360 assert(Scope->isAbstractScope());
361 assert(!Scope->getInlinedAt());
363 const MDNode *SP = Scope->getScopeNode();
365 ProcessedSPNodes.insert(SP);
367 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
368 // was inlined from another compile unit.
369 auto &CU = SPMap[SP];
370 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
371 CU.constructAbstractSubprogramScopeDIE(Scope);
375 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
376 if (!GenerateGnuPubSections)
379 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
382 // Create new DwarfCompileUnit for the given metadata node with tag
383 // DW_TAG_compile_unit.
384 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
385 StringRef FN = DIUnit.getFilename();
386 CompilationDir = DIUnit.getDirectory();
388 auto OwnedUnit = make_unique<DwarfCompileUnit>(
389 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
390 DwarfCompileUnit &NewCU = *OwnedUnit;
391 DIE &Die = NewCU.getUnitDie();
392 InfoHolder.addUnit(std::move(OwnedUnit));
394 NewCU.setSkeleton(constructSkeletonCU(NewCU));
396 // LTO with assembly output shares a single line table amongst multiple CUs.
397 // To avoid the compilation directory being ambiguous, let the line table
398 // explicitly describe the directory of all files, never relying on the
399 // compilation directory.
400 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
401 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
402 NewCU.getUniqueID(), CompilationDir);
404 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
405 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
406 DIUnit.getLanguage());
407 NewCU.addString(Die, dwarf::DW_AT_name, FN);
409 if (!useSplitDwarf()) {
410 NewCU.initStmtList(DwarfLineSectionSym);
412 // If we're using split dwarf the compilation dir is going to be in the
413 // skeleton CU and so we don't need to duplicate it here.
414 if (!CompilationDir.empty())
415 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
417 addGnuPubAttributes(NewCU, Die);
420 if (DIUnit.isOptimized())
421 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
423 StringRef Flags = DIUnit.getFlags();
425 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
427 if (unsigned RVer = DIUnit.getRunTimeVersion())
428 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
429 dwarf::DW_FORM_data1, RVer);
432 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
433 DwarfInfoDWOSectionSym);
435 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
436 DwarfInfoSectionSym);
438 CUMap.insert(std::make_pair(DIUnit, &NewCU));
439 CUDieMap.insert(std::make_pair(&Die, &NewCU));
443 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
445 DIImportedEntity Module(N);
446 assert(Module.Verify());
447 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
448 D->addChild(TheCU.constructImportedEntityDIE(Module));
451 // Emit all Dwarf sections that should come prior to the content. Create
452 // global DIEs and emit initial debug info sections. This is invoked by
453 // the target AsmPrinter.
454 void DwarfDebug::beginModule() {
455 if (DisableDebugInfoPrinting)
458 const Module *M = MMI->getModule();
460 FunctionDIs = makeSubprogramMap(*M);
462 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
465 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
467 // Emit initial sections so we can reference labels later.
470 SingleCU = CU_Nodes->getNumOperands() == 1;
472 for (MDNode *N : CU_Nodes->operands()) {
473 DICompileUnit CUNode(N);
474 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
475 DIArray ImportedEntities = CUNode.getImportedEntities();
476 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
477 ScopesWithImportedEntities.push_back(std::make_pair(
478 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
479 ImportedEntities.getElement(i)));
480 // Stable sort to preserve the order of appearance of imported entities.
481 // This is to avoid out-of-order processing of interdependent declarations
482 // within the same scope, e.g. { namespace A = base; namespace B = A; }
483 std::stable_sort(ScopesWithImportedEntities.begin(),
484 ScopesWithImportedEntities.end(), less_first());
485 DIArray GVs = CUNode.getGlobalVariables();
486 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
487 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
488 DIArray SPs = CUNode.getSubprograms();
489 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
490 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
491 DIArray EnumTypes = CUNode.getEnumTypes();
492 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
493 DIType Ty(EnumTypes.getElement(i));
494 // The enum types array by design contains pointers to
495 // MDNodes rather than DIRefs. Unique them here.
496 DIType UniqueTy(resolve(Ty.getRef()));
497 CU.getOrCreateTypeDIE(UniqueTy);
499 DIArray RetainedTypes = CUNode.getRetainedTypes();
500 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
501 DIType Ty(RetainedTypes.getElement(i));
502 // The retained types array by design contains pointers to
503 // MDNodes rather than DIRefs. Unique them here.
504 DIType UniqueTy(resolve(Ty.getRef()));
505 CU.getOrCreateTypeDIE(UniqueTy);
507 // Emit imported_modules last so that the relevant context is already
509 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
510 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
513 // Tell MMI that we have debug info.
514 MMI->setDebugInfoAvailability(true);
517 void DwarfDebug::finishVariableDefinitions() {
518 for (const auto &Var : ConcreteVariables) {
519 DIE *VariableDie = Var->getDIE();
521 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
522 // in the ConcreteVariables list, rather than looking it up again here.
523 // DIE::getUnit isn't simple - it walks parent pointers, etc.
524 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
526 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
527 if (AbsVar && AbsVar->getDIE()) {
528 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
531 Unit->applyVariableAttributes(*Var, *VariableDie);
535 void DwarfDebug::finishSubprogramDefinitions() {
536 for (const auto &P : SPMap)
537 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
538 CU.finishSubprogramDefinition(DISubprogram(P.first));
543 // Collect info for variables that were optimized out.
544 void DwarfDebug::collectDeadVariables() {
545 const Module *M = MMI->getModule();
547 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
548 for (MDNode *N : CU_Nodes->operands()) {
549 DICompileUnit TheCU(N);
550 // Construct subprogram DIE and add variables DIEs.
551 DwarfCompileUnit *SPCU =
552 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
553 assert(SPCU && "Unable to find Compile Unit!");
554 DIArray Subprograms = TheCU.getSubprograms();
555 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
556 DISubprogram SP(Subprograms.getElement(i));
557 if (ProcessedSPNodes.count(SP) != 0)
559 SPCU->collectDeadVariables(SP);
565 void DwarfDebug::finalizeModuleInfo() {
566 finishSubprogramDefinitions();
568 finishVariableDefinitions();
570 // Collect info for variables that were optimized out.
571 collectDeadVariables();
573 // Handle anything that needs to be done on a per-unit basis after
574 // all other generation.
575 for (const auto &P : CUMap) {
576 auto &TheCU = *P.second;
577 // Emit DW_AT_containing_type attribute to connect types with their
578 // vtable holding type.
579 TheCU.constructContainingTypeDIEs();
581 // Add CU specific attributes if we need to add any.
582 // If we're splitting the dwarf out now that we've got the entire
583 // CU then add the dwo id to it.
584 auto *SkCU = TheCU.getSkeleton();
585 if (useSplitDwarf()) {
586 // Emit a unique identifier for this CU.
587 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
588 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
589 dwarf::DW_FORM_data8, ID);
590 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
591 dwarf::DW_FORM_data8, ID);
593 // We don't keep track of which addresses are used in which CU so this
594 // is a bit pessimistic under LTO.
595 if (!AddrPool.isEmpty())
596 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
597 DwarfAddrSectionSym, DwarfAddrSectionSym);
598 if (!SkCU->getRangeLists().empty())
599 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
600 DwarfDebugRangeSectionSym,
601 DwarfDebugRangeSectionSym);
604 // If we have code split among multiple sections or non-contiguous
605 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
606 // remain in the .o file, otherwise add a DW_AT_low_pc.
607 // FIXME: We should use ranges allow reordering of code ala
608 // .subsections_via_symbols in mach-o. This would mean turning on
609 // ranges for all subprogram DIEs for mach-o.
610 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
611 if (unsigned NumRanges = TheCU.getRanges().size()) {
613 // A DW_AT_low_pc attribute may also be specified in combination with
614 // DW_AT_ranges to specify the default base address for use in
615 // location lists (see Section 2.6.2) and range lists (see Section
617 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
619 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
620 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
624 // Compute DIE offsets and sizes.
625 InfoHolder.computeSizeAndOffsets();
627 SkeletonHolder.computeSizeAndOffsets();
630 // Emit all Dwarf sections that should come after the content.
631 void DwarfDebug::endModule() {
632 assert(CurFn == nullptr);
633 assert(CurMI == nullptr);
635 // If we aren't actually generating debug info (check beginModule -
636 // conditionalized on !DisableDebugInfoPrinting and the presence of the
637 // llvm.dbg.cu metadata node)
638 if (!DwarfInfoSectionSym)
641 // Finalize the debug info for the module.
642 finalizeModuleInfo();
646 // Emit all the DIEs into a debug info section.
649 // Corresponding abbreviations into a abbrev section.
652 // Emit info into a debug aranges section.
653 if (GenerateARangeSection)
656 // Emit info into a debug ranges section.
659 if (useSplitDwarf()) {
662 emitDebugAbbrevDWO();
665 // Emit DWO addresses.
666 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
668 // Emit info into a debug loc section.
671 // Emit info into the dwarf accelerator table sections.
672 if (useDwarfAccelTables()) {
675 emitAccelNamespaces();
679 // Emit the pubnames and pubtypes sections if requested.
680 if (HasDwarfPubSections) {
681 emitDebugPubNames(GenerateGnuPubSections);
682 emitDebugPubTypes(GenerateGnuPubSections);
687 AbstractVariables.clear();
690 // Find abstract variable, if any, associated with Var.
691 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
692 DIVariable &Cleansed) {
693 LLVMContext &Ctx = DV->getContext();
694 // More then one inlined variable corresponds to one abstract variable.
695 // FIXME: This duplication of variables when inlining should probably be
696 // removed. It's done to allow each DIVariable to describe its location
697 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
698 // make it accurate then remove this duplication/cleansing stuff.
699 Cleansed = cleanseInlinedVariable(DV, Ctx);
700 auto I = AbstractVariables.find(Cleansed);
701 if (I != AbstractVariables.end())
702 return I->second.get();
706 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
708 return getExistingAbstractVariable(DV, Cleansed);
711 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
712 LexicalScope *Scope) {
713 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
714 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
715 AbstractVariables[Var] = std::move(AbsDbgVariable);
718 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
719 const MDNode *ScopeNode) {
720 DIVariable Cleansed = DV;
721 if (getExistingAbstractVariable(DV, Cleansed))
724 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
728 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
729 const MDNode *ScopeNode) {
730 DIVariable Cleansed = DV;
731 if (getExistingAbstractVariable(DV, Cleansed))
734 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
735 createAbstractVariable(Cleansed, Scope);
738 // Collect variable information from side table maintained by MMI.
739 void DwarfDebug::collectVariableInfoFromMMITable(
740 SmallPtrSetImpl<const MDNode *> &Processed) {
741 for (const auto &VI : MMI->getVariableDbgInfo()) {
744 Processed.insert(VI.Var);
745 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
747 // If variable scope is not found then skip this variable.
751 DIVariable DV(VI.Var);
752 DIExpression Expr(VI.Expr);
753 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
754 auto RegVar = make_unique<DbgVariable>(DV, Expr, this, VI.Slot);
755 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
756 ConcreteVariables.push_back(std::move(RegVar));
760 // Get .debug_loc entry for the instruction range starting at MI.
761 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
762 const MDNode *Expr = MI->getDebugExpression();
763 const MDNode *Var = MI->getDebugVariable();
765 assert(MI->getNumOperands() == 4);
766 if (MI->getOperand(0).isReg()) {
767 MachineLocation MLoc;
768 // If the second operand is an immediate, this is a
769 // register-indirect address.
770 if (!MI->getOperand(1).isImm())
771 MLoc.set(MI->getOperand(0).getReg());
773 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
774 return DebugLocEntry::Value(Var, Expr, MLoc);
776 if (MI->getOperand(0).isImm())
777 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
778 if (MI->getOperand(0).isFPImm())
779 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
780 if (MI->getOperand(0).isCImm())
781 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
783 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
786 /// Determine whether two variable pieces overlap.
787 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
788 if (!P1.isBitPiece() || !P2.isBitPiece())
790 unsigned l1 = P1.getBitPieceOffset();
791 unsigned l2 = P2.getBitPieceOffset();
792 unsigned r1 = l1 + P1.getBitPieceSize();
793 unsigned r2 = l2 + P2.getBitPieceSize();
794 // True where [l1,r1[ and [r1,r2[ overlap.
795 return (l1 < r2) && (l2 < r1);
798 /// Build the location list for all DBG_VALUEs in the function that
799 /// describe the same variable. If the ranges of several independent
800 /// pieces of the same variable overlap partially, split them up and
801 /// combine the ranges. The resulting DebugLocEntries are will have
802 /// strict monotonically increasing begin addresses and will never
807 // Ranges History [var, loc, piece ofs size]
808 // 0 | [x, (reg0, piece 0, 32)]
809 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
811 // 3 | [clobber reg0]
812 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
817 // [0-1] [x, (reg0, piece 0, 32)]
818 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
819 // [3-4] [x, (reg1, piece 32, 32)]
820 // [4- ] [x, (mem, piece 0, 64)]
822 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
823 const DbgValueHistoryMap::InstrRanges &Ranges) {
824 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
826 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
827 const MachineInstr *Begin = I->first;
828 const MachineInstr *End = I->second;
829 assert(Begin->isDebugValue() && "Invalid History entry");
831 // Check if a variable is inaccessible in this range.
832 if (Begin->getNumOperands() > 1 &&
833 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
838 // If this piece overlaps with any open ranges, truncate them.
839 DIExpression DIExpr = Begin->getDebugExpression();
840 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
841 [&](DebugLocEntry::Value R) {
842 return piecesOverlap(DIExpr, R.getExpression());
844 OpenRanges.erase(Last, OpenRanges.end());
846 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
847 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
849 const MCSymbol *EndLabel;
851 EndLabel = getLabelAfterInsn(End);
852 else if (std::next(I) == Ranges.end())
853 EndLabel = FunctionEndSym;
855 EndLabel = getLabelBeforeInsn(std::next(I)->first);
856 assert(EndLabel && "Forgot label after instruction ending a range!");
858 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
860 auto Value = getDebugLocValue(Begin);
861 DebugLocEntry Loc(StartLabel, EndLabel, Value);
862 bool couldMerge = false;
864 // If this is a piece, it may belong to the current DebugLocEntry.
865 if (DIExpr.isBitPiece()) {
866 // Add this value to the list of open ranges.
867 OpenRanges.push_back(Value);
869 // Attempt to add the piece to the last entry.
870 if (!DebugLoc.empty())
871 if (DebugLoc.back().MergeValues(Loc))
876 // Need to add a new DebugLocEntry. Add all values from still
877 // valid non-overlapping pieces.
878 if (OpenRanges.size())
879 Loc.addValues(OpenRanges);
881 DebugLoc.push_back(std::move(Loc));
884 // Attempt to coalesce the ranges of two otherwise identical
886 auto CurEntry = DebugLoc.rbegin();
887 auto PrevEntry = std::next(CurEntry);
888 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
892 dbgs() << CurEntry->getValues().size() << " Values:\n";
893 for (auto Value : CurEntry->getValues()) {
894 Value.getVariable()->dump();
895 Value.getExpression()->dump();
903 // Find variables for each lexical scope.
905 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
906 SmallPtrSetImpl<const MDNode *> &Processed) {
907 // Grab the variable info that was squirreled away in the MMI side-table.
908 collectVariableInfoFromMMITable(Processed);
910 for (const auto &I : DbgValues) {
911 DIVariable DV(I.first);
912 if (Processed.count(DV))
915 // Instruction ranges, specifying where DV is accessible.
916 const auto &Ranges = I.second;
920 LexicalScope *Scope = nullptr;
921 if (MDNode *IA = DV.getInlinedAt())
922 Scope = LScopes.findInlinedScope(DV.getContext(), IA);
924 Scope = LScopes.findLexicalScope(DV.getContext());
925 // If variable scope is not found then skip this variable.
929 Processed.insert(DV);
930 const MachineInstr *MInsn = Ranges.front().first;
931 assert(MInsn->isDebugValue() && "History must begin with debug value");
932 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
933 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
934 DbgVariable *RegVar = ConcreteVariables.back().get();
935 InfoHolder.addScopeVariable(Scope, RegVar);
937 // Check if the first DBG_VALUE is valid for the rest of the function.
938 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
941 // Handle multiple DBG_VALUE instructions describing one variable.
942 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
944 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
945 DebugLocList &LocList = DotDebugLocEntries.back();
948 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
950 // Build the location list for this variable.
951 buildLocationList(LocList.List, Ranges);
952 // Finalize the entry by lowering it into a DWARF bytestream.
953 for (auto &Entry : LocList.List)
954 Entry.finalize(*Asm, TypeIdentifierMap);
957 // Collect info for variables that were optimized out.
958 DIArray Variables = SP.getVariables();
959 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
960 DIVariable DV(Variables.getElement(i));
961 assert(DV.isVariable());
962 if (!Processed.insert(DV).second)
964 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
965 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
967 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
968 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
973 // Return Label preceding the instruction.
974 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
975 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
976 assert(Label && "Didn't insert label before instruction");
980 // Return Label immediately following the instruction.
981 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
982 return LabelsAfterInsn.lookup(MI);
985 // Process beginning of an instruction.
986 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
987 assert(CurMI == nullptr);
989 // Check if source location changes, but ignore DBG_VALUE locations.
990 if (!MI->isDebugValue()) {
991 DebugLoc DL = MI->getDebugLoc();
992 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
995 if (DL == PrologEndLoc) {
996 Flags |= DWARF2_FLAG_PROLOGUE_END;
997 PrologEndLoc = DebugLoc();
998 Flags |= DWARF2_FLAG_IS_STMT;
1001 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
1002 Flags |= DWARF2_FLAG_IS_STMT;
1004 if (!DL.isUnknown()) {
1005 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1006 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1008 recordSourceLine(0, 0, nullptr, 0);
1012 // Insert labels where requested.
1013 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1014 LabelsBeforeInsn.find(MI);
1017 if (I == LabelsBeforeInsn.end())
1020 // Label already assigned.
1025 PrevLabel = MMI->getContext().CreateTempSymbol();
1026 Asm->OutStreamer.EmitLabel(PrevLabel);
1028 I->second = PrevLabel;
1031 // Process end of an instruction.
1032 void DwarfDebug::endInstruction() {
1033 assert(CurMI != nullptr);
1034 // Don't create a new label after DBG_VALUE instructions.
1035 // They don't generate code.
1036 if (!CurMI->isDebugValue())
1037 PrevLabel = nullptr;
1039 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1040 LabelsAfterInsn.find(CurMI);
1044 if (I == LabelsAfterInsn.end())
1047 // Label already assigned.
1051 // We need a label after this instruction.
1053 PrevLabel = MMI->getContext().CreateTempSymbol();
1054 Asm->OutStreamer.EmitLabel(PrevLabel);
1056 I->second = PrevLabel;
1059 // Each LexicalScope has first instruction and last instruction to mark
1060 // beginning and end of a scope respectively. Create an inverse map that list
1061 // scopes starts (and ends) with an instruction. One instruction may start (or
1062 // end) multiple scopes. Ignore scopes that are not reachable.
1063 void DwarfDebug::identifyScopeMarkers() {
1064 SmallVector<LexicalScope *, 4> WorkList;
1065 WorkList.push_back(LScopes.getCurrentFunctionScope());
1066 while (!WorkList.empty()) {
1067 LexicalScope *S = WorkList.pop_back_val();
1069 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1070 if (!Children.empty())
1071 WorkList.append(Children.begin(), Children.end());
1073 if (S->isAbstractScope())
1076 for (const InsnRange &R : S->getRanges()) {
1077 assert(R.first && "InsnRange does not have first instruction!");
1078 assert(R.second && "InsnRange does not have second instruction!");
1079 requestLabelBeforeInsn(R.first);
1080 requestLabelAfterInsn(R.second);
1085 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1086 // First known non-DBG_VALUE and non-frame setup location marks
1087 // the beginning of the function body.
1088 for (const auto &MBB : *MF)
1089 for (const auto &MI : MBB)
1090 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1091 !MI.getDebugLoc().isUnknown()) {
1092 // Did the target forget to set the FrameSetup flag for CFI insns?
1093 assert(!MI.isCFIInstruction() &&
1094 "First non-frame-setup instruction is a CFI instruction.");
1095 return MI.getDebugLoc();
1100 // Gather pre-function debug information. Assumes being called immediately
1101 // after the function entry point has been emitted.
1102 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1105 // If there's no debug info for the function we're not going to do anything.
1106 if (!MMI->hasDebugInfo())
1109 auto DI = FunctionDIs.find(MF->getFunction());
1110 if (DI == FunctionDIs.end())
1113 // Grab the lexical scopes for the function, if we don't have any of those
1114 // then we're not going to be able to do anything.
1115 LScopes.initialize(*MF);
1116 if (LScopes.empty())
1119 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1121 // Make sure that each lexical scope will have a begin/end label.
1122 identifyScopeMarkers();
1124 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1125 // belongs to so that we add to the correct per-cu line table in the
1127 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1128 // FnScope->getScopeNode() and DI->second should represent the same function,
1129 // though they may not be the same MDNode due to inline functions merged in
1130 // LTO where the debug info metadata still differs (either due to distinct
1131 // written differences - two versions of a linkonce_odr function
1132 // written/copied into two separate files, or some sub-optimal metadata that
1133 // isn't structurally identical (see: file path/name info from clang, which
1134 // includes the directory of the cpp file being built, even when the file name
1135 // is absolute (such as an <> lookup header)))
1136 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1137 assert(TheCU && "Unable to find compile unit!");
1138 if (Asm->OutStreamer.hasRawTextSupport())
1139 // Use a single line table if we are generating assembly.
1140 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1142 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1144 // Emit a label for the function so that we have a beginning address.
1145 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1146 // Assumes in correct section after the entry point.
1147 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1149 // Calculate history for local variables.
1150 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1153 // Request labels for the full history.
1154 for (const auto &I : DbgValues) {
1155 const auto &Ranges = I.second;
1159 // The first mention of a function argument gets the FunctionBeginSym
1160 // label, so arguments are visible when breaking at function entry.
1161 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1162 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1163 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1164 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1165 if (Ranges.front().first->getDebugExpression().isBitPiece()) {
1166 // Mark all non-overlapping initial pieces.
1167 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1168 DIExpression Piece = I->first->getDebugExpression();
1169 if (std::all_of(Ranges.begin(), I,
1170 [&](DbgValueHistoryMap::InstrRange Pred) {
1171 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1173 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1180 for (const auto &Range : Ranges) {
1181 requestLabelBeforeInsn(Range.first);
1183 requestLabelAfterInsn(Range.second);
1187 PrevInstLoc = DebugLoc();
1188 PrevLabel = FunctionBeginSym;
1190 // Record beginning of function.
1191 PrologEndLoc = findPrologueEndLoc(MF);
1192 if (!PrologEndLoc.isUnknown()) {
1193 DebugLoc FnStartDL =
1194 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1196 // We'd like to list the prologue as "not statements" but GDB behaves
1197 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1198 recordSourceLine(FnStartDL.getLine(), FnStartDL.getCol(),
1199 FnStartDL.getScope(MF->getFunction()->getContext()),
1200 DWARF2_FLAG_IS_STMT);
1204 // Gather and emit post-function debug information.
1205 void DwarfDebug::endFunction(const MachineFunction *MF) {
1206 assert(CurFn == MF &&
1207 "endFunction should be called with the same function as beginFunction");
1209 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1210 !FunctionDIs.count(MF->getFunction())) {
1211 // If we don't have a lexical scope for this function then there will
1212 // be a hole in the range information. Keep note of this by setting the
1213 // previously used section to nullptr.
1219 // Define end label for subprogram.
1220 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1221 // Assumes in correct section after the entry point.
1222 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1224 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1225 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1227 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1228 DISubprogram SP(FnScope->getScopeNode());
1229 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1231 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1232 collectVariableInfo(TheCU, SP, ProcessedVars);
1234 // Add the range of this function to the list of ranges for the CU.
1235 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1237 // Under -gmlt, skip building the subprogram if there are no inlined
1238 // subroutines inside it.
1239 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1240 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1241 assert(InfoHolder.getScopeVariables().empty());
1242 assert(DbgValues.empty());
1243 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1244 // by a -gmlt CU. Add a test and remove this assertion.
1245 assert(AbstractVariables.empty());
1246 LabelsBeforeInsn.clear();
1247 LabelsAfterInsn.clear();
1248 PrevLabel = nullptr;
1254 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1256 // Construct abstract scopes.
1257 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1258 DISubprogram SP(AScope->getScopeNode());
1259 assert(SP.isSubprogram());
1260 // Collect info for variables that were optimized out.
1261 DIArray Variables = SP.getVariables();
1262 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1263 DIVariable DV(Variables.getElement(i));
1264 assert(DV && DV.isVariable());
1265 if (!ProcessedVars.insert(DV).second)
1267 ensureAbstractVariableIsCreated(DV, DV.getContext());
1268 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1269 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1271 constructAbstractSubprogramScopeDIE(AScope);
1274 TheCU.constructSubprogramScopeDIE(FnScope);
1275 if (auto *SkelCU = TheCU.getSkeleton())
1276 if (!LScopes.getAbstractScopesList().empty())
1277 SkelCU->constructSubprogramScopeDIE(FnScope);
1280 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1281 // DbgVariables except those that are also in AbstractVariables (since they
1282 // can be used cross-function)
1283 InfoHolder.getScopeVariables().clear();
1285 LabelsBeforeInsn.clear();
1286 LabelsAfterInsn.clear();
1287 PrevLabel = nullptr;
1291 // Register a source line with debug info. Returns the unique label that was
1292 // emitted and which provides correspondence to the source line list.
1293 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1298 unsigned Discriminator = 0;
1299 if (DIScope Scope = DIScope(S)) {
1300 assert(Scope.isScope());
1301 Fn = Scope.getFilename();
1302 Dir = Scope.getDirectory();
1303 if (Scope.isLexicalBlockFile())
1304 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1306 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1307 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1308 .getOrCreateSourceID(Fn, Dir);
1310 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1314 //===----------------------------------------------------------------------===//
1316 //===----------------------------------------------------------------------===//
1318 // Emit initial Dwarf sections with a label at the start of each one.
1319 void DwarfDebug::emitSectionLabels() {
1320 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1322 // Dwarf sections base addresses.
1323 DwarfInfoSectionSym =
1324 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1325 if (useSplitDwarf()) {
1326 DwarfInfoDWOSectionSym =
1327 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1328 DwarfTypesDWOSectionSym = emitSectionSym(
1329 Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1331 DwarfAbbrevSectionSym =
1332 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1333 if (useSplitDwarf())
1334 DwarfAbbrevDWOSectionSym = emitSectionSym(
1335 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1336 if (GenerateARangeSection)
1337 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1339 DwarfLineSectionSym =
1340 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1341 if (GenerateGnuPubSections) {
1342 DwarfGnuPubNamesSectionSym =
1343 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1344 DwarfGnuPubTypesSectionSym =
1345 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1346 } else if (HasDwarfPubSections) {
1347 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1348 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1351 DwarfStrSectionSym =
1352 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1353 if (useSplitDwarf()) {
1354 DwarfStrDWOSectionSym =
1355 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1356 DwarfAddrSectionSym =
1357 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1358 DwarfDebugLocSectionSym =
1359 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1361 DwarfDebugLocSectionSym =
1362 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1363 DwarfDebugRangeSectionSym =
1364 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1367 // Emit the debug info section.
1368 void DwarfDebug::emitDebugInfo() {
1369 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1371 Holder.emitUnits(DwarfAbbrevSectionSym);
1374 // Emit the abbreviation section.
1375 void DwarfDebug::emitAbbreviations() {
1376 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1378 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1381 // Emit the last address of the section and the end of the line matrix.
1382 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1383 // Define last address of section.
1384 Asm->OutStreamer.AddComment("Extended Op");
1387 Asm->OutStreamer.AddComment("Op size");
1388 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1389 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1390 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1392 Asm->OutStreamer.AddComment("Section end label");
1394 Asm->OutStreamer.EmitSymbolValue(
1395 Asm->GetTempSymbol("section_end", SectionEnd),
1396 Asm->getDataLayout().getPointerSize());
1398 // Mark end of matrix.
1399 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1405 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1406 StringRef TableName, StringRef SymName) {
1407 Accel.FinalizeTable(Asm, TableName);
1408 Asm->OutStreamer.SwitchSection(Section);
1409 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1410 Asm->OutStreamer.EmitLabel(SectionBegin);
1412 // Emit the full data.
1413 Accel.Emit(Asm, SectionBegin, this, DwarfStrSectionSym);
1416 // Emit visible names into a hashed accelerator table section.
1417 void DwarfDebug::emitAccelNames() {
1418 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1419 "Names", "names_begin");
1422 // Emit objective C classes and categories into a hashed accelerator table
1424 void DwarfDebug::emitAccelObjC() {
1425 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1426 "ObjC", "objc_begin");
1429 // Emit namespace dies into a hashed accelerator table.
1430 void DwarfDebug::emitAccelNamespaces() {
1431 emitAccel(AccelNamespace,
1432 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1433 "namespac", "namespac_begin");
1436 // Emit type dies into a hashed accelerator table.
1437 void DwarfDebug::emitAccelTypes() {
1438 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1439 "types", "types_begin");
1442 // Public name handling.
1443 // The format for the various pubnames:
1445 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1446 // for the DIE that is named.
1448 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1449 // into the CU and the index value is computed according to the type of value
1450 // for the DIE that is named.
1452 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1453 // it's the offset within the debug_info/debug_types dwo section, however, the
1454 // reference in the pubname header doesn't change.
1456 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1457 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1459 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1461 // We could have a specification DIE that has our most of our knowledge,
1462 // look for that now.
1463 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1465 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1466 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1467 Linkage = dwarf::GIEL_EXTERNAL;
1468 } else if (Die->findAttribute(dwarf::DW_AT_external))
1469 Linkage = dwarf::GIEL_EXTERNAL;
1471 switch (Die->getTag()) {
1472 case dwarf::DW_TAG_class_type:
1473 case dwarf::DW_TAG_structure_type:
1474 case dwarf::DW_TAG_union_type:
1475 case dwarf::DW_TAG_enumeration_type:
1476 return dwarf::PubIndexEntryDescriptor(
1477 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1478 ? dwarf::GIEL_STATIC
1479 : dwarf::GIEL_EXTERNAL);
1480 case dwarf::DW_TAG_typedef:
1481 case dwarf::DW_TAG_base_type:
1482 case dwarf::DW_TAG_subrange_type:
1483 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1484 case dwarf::DW_TAG_namespace:
1485 return dwarf::GIEK_TYPE;
1486 case dwarf::DW_TAG_subprogram:
1487 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1488 case dwarf::DW_TAG_variable:
1489 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1490 case dwarf::DW_TAG_enumerator:
1491 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1492 dwarf::GIEL_STATIC);
1494 return dwarf::GIEK_NONE;
1498 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1500 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1501 const MCSection *PSec =
1502 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1503 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1505 emitDebugPubSection(GnuStyle, PSec, "Names",
1506 &DwarfCompileUnit::getGlobalNames);
1509 void DwarfDebug::emitDebugPubSection(
1510 bool GnuStyle, const MCSection *PSec, StringRef Name,
1511 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1512 for (const auto &NU : CUMap) {
1513 DwarfCompileUnit *TheU = NU.second;
1515 const auto &Globals = (TheU->*Accessor)();
1517 if (Globals.empty())
1520 if (auto *Skeleton = TheU->getSkeleton())
1522 unsigned ID = TheU->getUniqueID();
1524 // Start the dwarf pubnames section.
1525 Asm->OutStreamer.SwitchSection(PSec);
1528 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1529 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1530 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1531 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1533 Asm->OutStreamer.EmitLabel(BeginLabel);
1535 Asm->OutStreamer.AddComment("DWARF Version");
1536 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1538 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1539 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1541 Asm->OutStreamer.AddComment("Compilation Unit Length");
1542 Asm->EmitInt32(TheU->getLength());
1544 // Emit the pubnames for this compilation unit.
1545 for (const auto &GI : Globals) {
1546 const char *Name = GI.getKeyData();
1547 const DIE *Entity = GI.second;
1549 Asm->OutStreamer.AddComment("DIE offset");
1550 Asm->EmitInt32(Entity->getOffset());
1553 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1554 Asm->OutStreamer.AddComment(
1555 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1556 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1557 Asm->EmitInt8(Desc.toBits());
1560 Asm->OutStreamer.AddComment("External Name");
1561 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1564 Asm->OutStreamer.AddComment("End Mark");
1566 Asm->OutStreamer.EmitLabel(EndLabel);
1570 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1571 const MCSection *PSec =
1572 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1573 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1575 emitDebugPubSection(GnuStyle, PSec, "Types",
1576 &DwarfCompileUnit::getGlobalTypes);
1579 // Emit visible names into a debug str section.
1580 void DwarfDebug::emitDebugStr() {
1581 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1582 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1586 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1587 const DebugLocEntry &Entry) {
1588 auto Comment = Entry.getComments().begin();
1589 auto End = Entry.getComments().end();
1590 for (uint8_t Byte : Entry.getDWARFBytes())
1591 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1594 static void emitDebugLocValue(const AsmPrinter &AP,
1595 const DITypeIdentifierMap &TypeIdentifierMap,
1596 ByteStreamer &Streamer,
1597 const DebugLocEntry::Value &Value,
1598 unsigned PieceOffsetInBits) {
1599 DIVariable DV = Value.getVariable();
1600 DebugLocDwarfExpression DwarfExpr(
1601 *AP.TM.getSubtargetImpl()->getRegisterInfo(),
1602 AP.getDwarfDebug()->getDwarfVersion(), Streamer);
1604 if (Value.isInt()) {
1605 DIBasicType BTy(DV.getType().resolve(TypeIdentifierMap));
1606 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1607 BTy.getEncoding() == dwarf::DW_ATE_signed_char))
1608 DwarfExpr.AddSignedConstant(Value.getInt());
1610 DwarfExpr.AddUnsignedConstant(Value.getInt());
1611 } else if (Value.isLocation()) {
1612 MachineLocation Loc = Value.getLoc();
1613 DIExpression Expr = Value.getExpression();
1614 if (!Expr || (Expr.getNumElements() == 0))
1616 AP.EmitDwarfRegOp(Streamer, Loc);
1618 // Complex address entry.
1619 if (Loc.getOffset()) {
1620 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1621 DwarfExpr.AddExpression(Expr.begin(), Expr.end(), PieceOffsetInBits);
1623 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1627 // else ... ignore constant fp. There is not any good way to
1628 // to represent them here in dwarf.
1633 void DebugLocEntry::finalize(const AsmPrinter &AP,
1634 const DITypeIdentifierMap &TypeIdentifierMap) {
1635 BufferByteStreamer Streamer(DWARFBytes, Comments);
1636 const DebugLocEntry::Value Value = Values[0];
1637 if (Value.isBitPiece()) {
1638 // Emit all pieces that belong to the same variable and range.
1639 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1640 return P.isBitPiece();
1641 }) && "all values are expected to be pieces");
1642 assert(std::is_sorted(Values.begin(), Values.end()) &&
1643 "pieces are expected to be sorted");
1645 unsigned Offset = 0;
1646 for (auto Piece : Values) {
1647 DIExpression Expr = Piece.getExpression();
1648 unsigned PieceOffset = Expr.getBitPieceOffset();
1649 unsigned PieceSize = Expr.getBitPieceSize();
1650 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1651 if (Offset < PieceOffset) {
1652 // The DWARF spec seriously mandates pieces with no locations for gaps.
1653 DebugLocDwarfExpression Expr(
1654 *AP.TM.getSubtargetImpl()->getRegisterInfo(),
1655 AP.getDwarfDebug()->getDwarfVersion(), Streamer);
1656 Expr.AddOpPiece(PieceOffset-Offset, 0);
1657 Offset += PieceOffset-Offset;
1659 Offset += PieceSize;
1662 DIVariable Var = Piece.getVariable();
1663 unsigned VarSize = Var.getSizeInBits(TypeIdentifierMap);
1664 assert(PieceSize+PieceOffset <= VarSize
1665 && "piece is larger than or outside of variable");
1666 assert(PieceSize != VarSize
1667 && "piece covers entire variable");
1669 emitDebugLocValue(AP, TypeIdentifierMap, Streamer, Piece, PieceOffset);
1672 assert(Values.size() == 1 && "only pieces may have >1 value");
1673 emitDebugLocValue(AP, TypeIdentifierMap, Streamer, Value, 0);
1678 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1679 Asm->OutStreamer.AddComment("Loc expr size");
1680 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1681 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1682 Asm->EmitLabelDifference(end, begin, 2);
1683 Asm->OutStreamer.EmitLabel(begin);
1685 APByteStreamer Streamer(*Asm);
1686 emitDebugLocEntry(Streamer, Entry);
1688 Asm->OutStreamer.EmitLabel(end);
1691 // Emit locations into the debug loc section.
1692 void DwarfDebug::emitDebugLoc() {
1693 // Start the dwarf loc section.
1694 Asm->OutStreamer.SwitchSection(
1695 Asm->getObjFileLowering().getDwarfLocSection());
1696 unsigned char Size = Asm->getDataLayout().getPointerSize();
1697 for (const auto &DebugLoc : DotDebugLocEntries) {
1698 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1699 const DwarfCompileUnit *CU = DebugLoc.CU;
1700 for (const auto &Entry : DebugLoc.List) {
1701 // Set up the range. This range is relative to the entry point of the
1702 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1703 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1704 if (auto *Base = CU->getBaseAddress()) {
1705 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1706 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1708 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1709 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1712 emitDebugLocEntryLocation(Entry);
1714 Asm->OutStreamer.EmitIntValue(0, Size);
1715 Asm->OutStreamer.EmitIntValue(0, Size);
1719 void DwarfDebug::emitDebugLocDWO() {
1720 Asm->OutStreamer.SwitchSection(
1721 Asm->getObjFileLowering().getDwarfLocDWOSection());
1722 for (const auto &DebugLoc : DotDebugLocEntries) {
1723 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1724 for (const auto &Entry : DebugLoc.List) {
1725 // Just always use start_length for now - at least that's one address
1726 // rather than two. We could get fancier and try to, say, reuse an
1727 // address we know we've emitted elsewhere (the start of the function?
1728 // The start of the CU or CU subrange that encloses this range?)
1729 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1730 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1731 Asm->EmitULEB128(idx);
1732 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1734 emitDebugLocEntryLocation(Entry);
1736 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1741 const MCSymbol *Start, *End;
1744 // Emit a debug aranges section, containing a CU lookup for any
1745 // address we can tie back to a CU.
1746 void DwarfDebug::emitDebugARanges() {
1747 // Provides a unique id per text section.
1748 DenseMap<const MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1750 // Prime section data.
1751 SectionMap[Asm->getObjFileLowering().getTextSection()];
1753 // Filter labels by section.
1754 for (const SymbolCU &SCU : ArangeLabels) {
1755 if (SCU.Sym->isInSection()) {
1756 // Make a note of this symbol and it's section.
1757 const MCSection *Section = &SCU.Sym->getSection();
1758 if (!Section->getKind().isMetadata())
1759 SectionMap[Section].push_back(SCU);
1761 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1762 // appear in the output. This sucks as we rely on sections to build
1763 // arange spans. We can do it without, but it's icky.
1764 SectionMap[nullptr].push_back(SCU);
1768 // Build a list of sections used.
1769 std::vector<const MCSection *> Sections;
1770 for (const auto &it : SectionMap) {
1771 const MCSection *Section = it.first;
1772 Sections.push_back(Section);
1775 // Sort the sections into order.
1776 // This is only done to ensure consistent output order across different runs.
1777 std::sort(Sections.begin(), Sections.end(), SectionSort);
1779 // Add terminating symbols for each section.
1780 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
1781 const MCSection *Section = Sections[ID];
1782 MCSymbol *Sym = nullptr;
1785 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1786 // if we know the section name up-front. For user-created sections, the
1787 // resulting label may not be valid to use as a label. (section names can
1788 // use a greater set of characters on some systems)
1789 Sym = Asm->GetTempSymbol("debug_end", ID);
1790 Asm->OutStreamer.SwitchSection(Section);
1791 Asm->OutStreamer.EmitLabel(Sym);
1794 // Insert a final terminator.
1795 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1798 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1800 for (const MCSection *Section : Sections) {
1801 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1802 if (List.size() < 2)
1805 // If we have no section (e.g. common), just write out
1806 // individual spans for each symbol.
1808 for (const SymbolCU &Cur : List) {
1810 Span.Start = Cur.Sym;
1813 Spans[Cur.CU].push_back(Span);
1818 // Sort the symbols by offset within the section.
1819 std::sort(List.begin(), List.end(),
1820 [&](const SymbolCU &A, const SymbolCU &B) {
1821 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1822 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1824 // Symbols with no order assigned should be placed at the end.
1825 // (e.g. section end labels)
1833 // Build spans between each label.
1834 const MCSymbol *StartSym = List[0].Sym;
1835 for (size_t n = 1, e = List.size(); n < e; n++) {
1836 const SymbolCU &Prev = List[n - 1];
1837 const SymbolCU &Cur = List[n];
1839 // Try and build the longest span we can within the same CU.
1840 if (Cur.CU != Prev.CU) {
1842 Span.Start = StartSym;
1844 Spans[Prev.CU].push_back(Span);
1850 // Start the dwarf aranges section.
1851 Asm->OutStreamer.SwitchSection(
1852 Asm->getObjFileLowering().getDwarfARangesSection());
1854 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1856 // Build a list of CUs used.
1857 std::vector<DwarfCompileUnit *> CUs;
1858 for (const auto &it : Spans) {
1859 DwarfCompileUnit *CU = it.first;
1863 // Sort the CU list (again, to ensure consistent output order).
1864 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1865 return A->getUniqueID() < B->getUniqueID();
1868 // Emit an arange table for each CU we used.
1869 for (DwarfCompileUnit *CU : CUs) {
1870 std::vector<ArangeSpan> &List = Spans[CU];
1872 // Describe the skeleton CU's offset and length, not the dwo file's.
1873 if (auto *Skel = CU->getSkeleton())
1876 // Emit size of content not including length itself.
1877 unsigned ContentSize =
1878 sizeof(int16_t) + // DWARF ARange version number
1879 sizeof(int32_t) + // Offset of CU in the .debug_info section
1880 sizeof(int8_t) + // Pointer Size (in bytes)
1881 sizeof(int8_t); // Segment Size (in bytes)
1883 unsigned TupleSize = PtrSize * 2;
1885 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1887 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1889 ContentSize += Padding;
1890 ContentSize += (List.size() + 1) * TupleSize;
1892 // For each compile unit, write the list of spans it covers.
1893 Asm->OutStreamer.AddComment("Length of ARange Set");
1894 Asm->EmitInt32(ContentSize);
1895 Asm->OutStreamer.AddComment("DWARF Arange version number");
1896 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1897 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1898 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1899 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1900 Asm->EmitInt8(PtrSize);
1901 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1904 Asm->OutStreamer.EmitFill(Padding, 0xff);
1906 for (const ArangeSpan &Span : List) {
1907 Asm->EmitLabelReference(Span.Start, PtrSize);
1909 // Calculate the size as being from the span start to it's end.
1911 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1913 // For symbols without an end marker (e.g. common), we
1914 // write a single arange entry containing just that one symbol.
1915 uint64_t Size = SymSize[Span.Start];
1919 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1923 Asm->OutStreamer.AddComment("ARange terminator");
1924 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1925 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1929 // Emit visible names into a debug ranges section.
1930 void DwarfDebug::emitDebugRanges() {
1931 // Start the dwarf ranges section.
1932 Asm->OutStreamer.SwitchSection(
1933 Asm->getObjFileLowering().getDwarfRangesSection());
1935 // Size for our labels.
1936 unsigned char Size = Asm->getDataLayout().getPointerSize();
1938 // Grab the specific ranges for the compile units in the module.
1939 for (const auto &I : CUMap) {
1940 DwarfCompileUnit *TheCU = I.second;
1942 if (auto *Skel = TheCU->getSkeleton())
1945 // Iterate over the misc ranges for the compile units in the module.
1946 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1947 // Emit our symbol so we can find the beginning of the range.
1948 Asm->OutStreamer.EmitLabel(List.getSym());
1950 for (const RangeSpan &Range : List.getRanges()) {
1951 const MCSymbol *Begin = Range.getStart();
1952 const MCSymbol *End = Range.getEnd();
1953 assert(Begin && "Range without a begin symbol?");
1954 assert(End && "Range without an end symbol?");
1955 if (auto *Base = TheCU->getBaseAddress()) {
1956 Asm->EmitLabelDifference(Begin, Base, Size);
1957 Asm->EmitLabelDifference(End, Base, Size);
1959 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1960 Asm->OutStreamer.EmitSymbolValue(End, Size);
1964 // And terminate the list with two 0 values.
1965 Asm->OutStreamer.EmitIntValue(0, Size);
1966 Asm->OutStreamer.EmitIntValue(0, Size);
1971 // DWARF5 Experimental Separate Dwarf emitters.
1973 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1974 std::unique_ptr<DwarfUnit> NewU) {
1975 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1976 U.getCUNode().getSplitDebugFilename());
1978 if (!CompilationDir.empty())
1979 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1981 addGnuPubAttributes(*NewU, Die);
1983 SkeletonHolder.addUnit(std::move(NewU));
1986 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1987 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1988 // DW_AT_addr_base, DW_AT_ranges_base.
1989 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1991 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1992 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1993 DwarfCompileUnit &NewCU = *OwnedUnit;
1994 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
1995 DwarfInfoSectionSym);
1997 NewCU.initStmtList(DwarfLineSectionSym);
1999 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2004 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2005 // compile units that would normally be in debug_info.
2006 void DwarfDebug::emitDebugInfoDWO() {
2007 assert(useSplitDwarf() && "No split dwarf debug info?");
2008 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2009 // emit relocations into the dwo file.
2010 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2013 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2014 // abbreviations for the .debug_info.dwo section.
2015 void DwarfDebug::emitDebugAbbrevDWO() {
2016 assert(useSplitDwarf() && "No split dwarf?");
2017 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2020 void DwarfDebug::emitDebugLineDWO() {
2021 assert(useSplitDwarf() && "No split dwarf?");
2022 Asm->OutStreamer.SwitchSection(
2023 Asm->getObjFileLowering().getDwarfLineDWOSection());
2024 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2027 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2028 // string section and is identical in format to traditional .debug_str
2030 void DwarfDebug::emitDebugStrDWO() {
2031 assert(useSplitDwarf() && "No split dwarf?");
2032 const MCSection *OffSec =
2033 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2034 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2038 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2039 if (!useSplitDwarf())
2042 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2043 return &SplitTypeUnitFileTable;
2046 static uint64_t makeTypeSignature(StringRef Identifier) {
2048 Hash.update(Identifier);
2049 // ... take the least significant 8 bytes and return those. Our MD5
2050 // implementation always returns its results in little endian, swap bytes
2052 MD5::MD5Result Result;
2054 return support::endian::read64le(Result + 8);
2057 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2058 StringRef Identifier, DIE &RefDie,
2059 DICompositeType CTy) {
2060 // Fast path if we're building some type units and one has already used the
2061 // address pool we know we're going to throw away all this work anyway, so
2062 // don't bother building dependent types.
2063 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2066 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2068 CU.addDIETypeSignature(RefDie, *TU);
2072 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2073 AddrPool.resetUsedFlag();
2075 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2076 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2077 this, &InfoHolder, getDwoLineTable(CU));
2078 DwarfTypeUnit &NewTU = *OwnedUnit;
2079 DIE &UnitDie = NewTU.getUnitDie();
2081 TypeUnitsUnderConstruction.push_back(
2082 std::make_pair(std::move(OwnedUnit), CTy));
2084 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2087 uint64_t Signature = makeTypeSignature(Identifier);
2088 NewTU.setTypeSignature(Signature);
2090 if (useSplitDwarf())
2091 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2093 CU.applyStmtList(UnitDie);
2095 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2098 NewTU.setType(NewTU.createTypeDIE(CTy));
2101 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2102 TypeUnitsUnderConstruction.clear();
2104 // Types referencing entries in the address table cannot be placed in type
2106 if (AddrPool.hasBeenUsed()) {
2108 // Remove all the types built while building this type.
2109 // This is pessimistic as some of these types might not be dependent on
2110 // the type that used an address.
2111 for (const auto &TU : TypeUnitsToAdd)
2112 DwarfTypeUnits.erase(TU.second);
2114 // Construct this type in the CU directly.
2115 // This is inefficient because all the dependent types will be rebuilt
2116 // from scratch, including building them in type units, discovering that
2117 // they depend on addresses, throwing them out and rebuilding them.
2118 CU.constructTypeDIE(RefDie, CTy);
2122 // If the type wasn't dependent on fission addresses, finish adding the type
2123 // and all its dependent types.
2124 for (auto &TU : TypeUnitsToAdd)
2125 InfoHolder.addUnit(std::move(TU.first));
2127 CU.addDIETypeSignature(RefDie, NewTU);
2130 // Accelerator table mutators - add each name along with its companion
2131 // DIE to the proper table while ensuring that the name that we're going
2132 // to reference is in the string table. We do this since the names we
2133 // add may not only be identical to the names in the DIE.
2134 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2135 if (!useDwarfAccelTables())
2137 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2141 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2142 if (!useDwarfAccelTables())
2144 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2148 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2149 if (!useDwarfAccelTables())
2151 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2155 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2156 if (!useDwarfAccelTables())
2158 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),