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(int64_t Value) {
115 BS.EmitSLEB128(Value, Twine(Value));
118 void DebugLocDwarfExpression::EmitUnsigned(uint64_t 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 IsPS4(Triple(A->getTargetTriple()).isPS4()),
197 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
198 dwarf::DW_FORM_data4)),
199 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
200 dwarf::DW_FORM_data4)),
201 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
202 dwarf::DW_FORM_data4)),
203 AccelTypes(TypeAtoms) {
208 // Turn on accelerator tables for Darwin by default, pubnames by
209 // default for non-Darwin/PS4, and handle split dwarf.
210 if (DwarfAccelTables == Default)
211 HasDwarfAccelTables = IsDarwin;
213 HasDwarfAccelTables = DwarfAccelTables == Enable;
215 if (SplitDwarf == Default)
216 HasSplitDwarf = false;
218 HasSplitDwarf = SplitDwarf == Enable;
220 if (DwarfPubSections == Default)
221 HasDwarfPubSections = !IsDarwin && !IsPS4;
223 HasDwarfPubSections = DwarfPubSections == Enable;
225 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
226 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
227 : MMI->getModule()->getDwarfVersion();
229 // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3).
230 // Everybody else uses GNU's.
231 UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3;
233 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
236 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
241 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
242 DwarfDebug::~DwarfDebug() { }
244 static bool isObjCClass(StringRef Name) {
245 return Name.startswith("+") || Name.startswith("-");
248 static bool hasObjCCategory(StringRef Name) {
249 if (!isObjCClass(Name))
252 return Name.find(") ") != StringRef::npos;
255 static void getObjCClassCategory(StringRef In, StringRef &Class,
256 StringRef &Category) {
257 if (!hasObjCCategory(In)) {
258 Class = In.slice(In.find('[') + 1, In.find(' '));
263 Class = In.slice(In.find('[') + 1, In.find('('));
264 Category = In.slice(In.find('[') + 1, In.find(' '));
268 static StringRef getObjCMethodName(StringRef In) {
269 return In.slice(In.find(' ') + 1, In.find(']'));
272 // Add the various names to the Dwarf accelerator table names.
273 // TODO: Determine whether or not we should add names for programs
274 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
275 // is only slightly different than the lookup of non-standard ObjC names.
276 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
277 if (!SP.isDefinition())
279 addAccelName(SP.getName(), Die);
281 // If the linkage name is different than the name, go ahead and output
282 // that as well into the name table.
283 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
284 addAccelName(SP.getLinkageName(), Die);
286 // If this is an Objective-C selector name add it to the ObjC accelerator
288 if (isObjCClass(SP.getName())) {
289 StringRef Class, Category;
290 getObjCClassCategory(SP.getName(), Class, Category);
291 addAccelObjC(Class, Die);
293 addAccelObjC(Category, Die);
294 // Also add the base method name to the name table.
295 addAccelName(getObjCMethodName(SP.getName()), Die);
299 /// isSubprogramContext - Return true if Context is either a subprogram
300 /// or another context nested inside a subprogram.
301 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
304 DIDescriptor D(Context);
305 if (D.isSubprogram())
308 return isSubprogramContext(resolve(DIType(Context).getContext()));
312 /// Check whether we should create a DIE for the given Scope, return true
313 /// if we don't create a DIE (the corresponding DIE is null).
314 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
315 if (Scope->isAbstractScope())
318 // We don't create a DIE if there is no Range.
319 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
323 if (Ranges.size() > 1)
326 // We don't create a DIE if we have a single Range and the end label
328 return !getLabelAfterInsn(Ranges.front().second);
331 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
333 if (auto *SkelCU = CU.getSkeleton())
337 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
338 assert(Scope && Scope->getScopeNode());
339 assert(Scope->isAbstractScope());
340 assert(!Scope->getInlinedAt());
342 const MDNode *SP = Scope->getScopeNode();
344 ProcessedSPNodes.insert(SP);
346 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
347 // was inlined from another compile unit.
348 auto &CU = SPMap[SP];
349 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
350 CU.constructAbstractSubprogramScopeDIE(Scope);
354 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
355 if (!GenerateGnuPubSections)
358 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
361 // Create new DwarfCompileUnit for the given metadata node with tag
362 // DW_TAG_compile_unit.
363 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
364 StringRef FN = DIUnit.getFilename();
365 CompilationDir = DIUnit.getDirectory();
367 auto OwnedUnit = make_unique<DwarfCompileUnit>(
368 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
369 DwarfCompileUnit &NewCU = *OwnedUnit;
370 DIE &Die = NewCU.getUnitDie();
371 InfoHolder.addUnit(std::move(OwnedUnit));
373 NewCU.setSkeleton(constructSkeletonCU(NewCU));
375 // LTO with assembly output shares a single line table amongst multiple CUs.
376 // To avoid the compilation directory being ambiguous, let the line table
377 // explicitly describe the directory of all files, never relying on the
378 // compilation directory.
379 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
380 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
381 NewCU.getUniqueID(), CompilationDir);
383 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
384 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
385 DIUnit.getLanguage());
386 NewCU.addString(Die, dwarf::DW_AT_name, FN);
388 if (!useSplitDwarf()) {
389 NewCU.initStmtList();
391 // If we're using split dwarf the compilation dir is going to be in the
392 // skeleton CU and so we don't need to duplicate it here.
393 if (!CompilationDir.empty())
394 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
396 addGnuPubAttributes(NewCU, Die);
399 if (DIUnit.isOptimized())
400 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
402 StringRef Flags = DIUnit.getFlags();
404 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
406 if (unsigned RVer = DIUnit.getRunTimeVersion())
407 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
408 dwarf::DW_FORM_data1, RVer);
411 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
413 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
415 CUMap.insert(std::make_pair(DIUnit, &NewCU));
416 CUDieMap.insert(std::make_pair(&Die, &NewCU));
420 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
422 DIImportedEntity Module(N);
423 assert(Module.Verify());
424 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
425 D->addChild(TheCU.constructImportedEntityDIE(Module));
428 // Emit all Dwarf sections that should come prior to the content. Create
429 // global DIEs and emit initial debug info sections. This is invoked by
430 // the target AsmPrinter.
431 void DwarfDebug::beginModule() {
432 if (DisableDebugInfoPrinting)
435 const Module *M = MMI->getModule();
437 FunctionDIs = makeSubprogramMap(*M);
439 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
442 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
444 SingleCU = CU_Nodes->getNumOperands() == 1;
446 for (MDNode *N : CU_Nodes->operands()) {
447 DICompileUnit CUNode(N);
448 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
449 DIArray ImportedEntities = CUNode.getImportedEntities();
450 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
451 ScopesWithImportedEntities.push_back(std::make_pair(
452 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
453 ImportedEntities.getElement(i)));
454 // Stable sort to preserve the order of appearance of imported entities.
455 // This is to avoid out-of-order processing of interdependent declarations
456 // within the same scope, e.g. { namespace A = base; namespace B = A; }
457 std::stable_sort(ScopesWithImportedEntities.begin(),
458 ScopesWithImportedEntities.end(), less_first());
459 DIArray GVs = CUNode.getGlobalVariables();
460 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
461 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
462 DIArray SPs = CUNode.getSubprograms();
463 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
464 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
465 DIArray EnumTypes = CUNode.getEnumTypes();
466 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
467 DIType Ty(EnumTypes.getElement(i));
468 // The enum types array by design contains pointers to
469 // MDNodes rather than DIRefs. Unique them here.
470 DIType UniqueTy(resolve(Ty.getRef()));
471 CU.getOrCreateTypeDIE(UniqueTy);
473 DIArray RetainedTypes = CUNode.getRetainedTypes();
474 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
475 DIType Ty(RetainedTypes.getElement(i));
476 // The retained types array by design contains pointers to
477 // MDNodes rather than DIRefs. Unique them here.
478 DIType UniqueTy(resolve(Ty.getRef()));
479 CU.getOrCreateTypeDIE(UniqueTy);
481 // Emit imported_modules last so that the relevant context is already
483 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
484 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
487 // Tell MMI that we have debug info.
488 MMI->setDebugInfoAvailability(true);
491 void DwarfDebug::finishVariableDefinitions() {
492 for (const auto &Var : ConcreteVariables) {
493 DIE *VariableDie = Var->getDIE();
495 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
496 // in the ConcreteVariables list, rather than looking it up again here.
497 // DIE::getUnit isn't simple - it walks parent pointers, etc.
498 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
500 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
501 if (AbsVar && AbsVar->getDIE()) {
502 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
505 Unit->applyVariableAttributes(*Var, *VariableDie);
509 void DwarfDebug::finishSubprogramDefinitions() {
510 for (const auto &P : SPMap)
511 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
512 CU.finishSubprogramDefinition(DISubprogram(P.first));
517 // Collect info for variables that were optimized out.
518 void DwarfDebug::collectDeadVariables() {
519 const Module *M = MMI->getModule();
521 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
522 for (MDNode *N : CU_Nodes->operands()) {
523 DICompileUnit TheCU(N);
524 // Construct subprogram DIE and add variables DIEs.
525 DwarfCompileUnit *SPCU =
526 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
527 assert(SPCU && "Unable to find Compile Unit!");
528 DIArray Subprograms = TheCU.getSubprograms();
529 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
530 DISubprogram SP(Subprograms.getElement(i));
531 if (ProcessedSPNodes.count(SP) != 0)
533 SPCU->collectDeadVariables(SP);
539 void DwarfDebug::finalizeModuleInfo() {
540 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
542 finishSubprogramDefinitions();
544 finishVariableDefinitions();
546 // Collect info for variables that were optimized out.
547 collectDeadVariables();
549 // Handle anything that needs to be done on a per-unit basis after
550 // all other generation.
551 for (const auto &P : CUMap) {
552 auto &TheCU = *P.second;
553 // Emit DW_AT_containing_type attribute to connect types with their
554 // vtable holding type.
555 TheCU.constructContainingTypeDIEs();
557 // Add CU specific attributes if we need to add any.
558 // If we're splitting the dwarf out now that we've got the entire
559 // CU then add the dwo id to it.
560 auto *SkCU = TheCU.getSkeleton();
561 if (useSplitDwarf()) {
562 // Emit a unique identifier for this CU.
563 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
564 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
565 dwarf::DW_FORM_data8, ID);
566 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
567 dwarf::DW_FORM_data8, ID);
569 // We don't keep track of which addresses are used in which CU so this
570 // is a bit pessimistic under LTO.
571 if (!AddrPool.isEmpty()) {
572 const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol();
573 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
576 if (!SkCU->getRangeLists().empty()) {
577 const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol();
578 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
583 // If we have code split among multiple sections or non-contiguous
584 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
585 // remain in the .o file, otherwise add a DW_AT_low_pc.
586 // FIXME: We should use ranges allow reordering of code ala
587 // .subsections_via_symbols in mach-o. This would mean turning on
588 // ranges for all subprogram DIEs for mach-o.
589 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
590 if (unsigned NumRanges = TheCU.getRanges().size()) {
592 // A DW_AT_low_pc attribute may also be specified in combination with
593 // DW_AT_ranges to specify the default base address for use in
594 // location lists (see Section 2.6.2) and range lists (see Section
596 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
598 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
599 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
603 // Compute DIE offsets and sizes.
604 InfoHolder.computeSizeAndOffsets();
606 SkeletonHolder.computeSizeAndOffsets();
609 // Emit all Dwarf sections that should come after the content.
610 void DwarfDebug::endModule() {
611 assert(CurFn == nullptr);
612 assert(CurMI == nullptr);
614 // If we aren't actually generating debug info (check beginModule -
615 // conditionalized on !DisableDebugInfoPrinting and the presence of the
616 // llvm.dbg.cu metadata node)
617 if (!MMI->hasDebugInfo())
620 // Finalize the debug info for the module.
621 finalizeModuleInfo();
628 // Emit info into a debug loc section.
631 // Corresponding abbreviations into a abbrev section.
634 // Emit all the DIEs into a debug info section.
637 // Emit info into a debug aranges section.
638 if (GenerateARangeSection)
641 // Emit info into a debug ranges section.
644 if (useSplitDwarf()) {
647 emitDebugAbbrevDWO();
649 // Emit DWO addresses.
650 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
653 // Emit info into the dwarf accelerator table sections.
654 if (useDwarfAccelTables()) {
657 emitAccelNamespaces();
661 // Emit the pubnames and pubtypes sections if requested.
662 if (HasDwarfPubSections) {
663 emitDebugPubNames(GenerateGnuPubSections);
664 emitDebugPubTypes(GenerateGnuPubSections);
669 AbstractVariables.clear();
672 // Find abstract variable, if any, associated with Var.
673 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
674 DIVariable &Cleansed) {
675 LLVMContext &Ctx = DV->getContext();
676 // More then one inlined variable corresponds to one abstract variable.
677 // FIXME: This duplication of variables when inlining should probably be
678 // removed. It's done to allow each DIVariable to describe its location
679 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
680 // make it accurate then remove this duplication/cleansing stuff.
681 Cleansed = cleanseInlinedVariable(DV, Ctx);
682 auto I = AbstractVariables.find(Cleansed);
683 if (I != AbstractVariables.end())
684 return I->second.get();
688 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
690 return getExistingAbstractVariable(DV, Cleansed);
693 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
694 LexicalScope *Scope) {
695 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
696 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
697 AbstractVariables[Var] = std::move(AbsDbgVariable);
700 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
701 const MDNode *ScopeNode) {
702 DIVariable Cleansed = DV;
703 if (getExistingAbstractVariable(DV, Cleansed))
706 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
710 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
711 const MDNode *ScopeNode) {
712 DIVariable Cleansed = DV;
713 if (getExistingAbstractVariable(DV, Cleansed))
716 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
717 createAbstractVariable(Cleansed, Scope);
720 // Collect variable information from side table maintained by MMI.
721 void DwarfDebug::collectVariableInfoFromMMITable(
722 SmallPtrSetImpl<const MDNode *> &Processed) {
723 for (const auto &VI : MMI->getVariableDbgInfo()) {
726 Processed.insert(VI.Var);
727 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
729 // If variable scope is not found then skip this variable.
733 DIVariable DV(VI.Var);
734 DIExpression Expr(VI.Expr);
735 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
736 auto RegVar = make_unique<DbgVariable>(DV, Expr, this, VI.Slot);
737 if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
738 ConcreteVariables.push_back(std::move(RegVar));
742 // Get .debug_loc entry for the instruction range starting at MI.
743 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
744 const MDNode *Expr = MI->getDebugExpression();
745 const MDNode *Var = MI->getDebugVariable();
747 assert(MI->getNumOperands() == 4);
748 if (MI->getOperand(0).isReg()) {
749 MachineLocation MLoc;
750 // If the second operand is an immediate, this is a
751 // register-indirect address.
752 if (!MI->getOperand(1).isImm())
753 MLoc.set(MI->getOperand(0).getReg());
755 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
756 return DebugLocEntry::Value(Var, Expr, MLoc);
758 if (MI->getOperand(0).isImm())
759 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
760 if (MI->getOperand(0).isFPImm())
761 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
762 if (MI->getOperand(0).isCImm())
763 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
765 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
768 /// Determine whether two variable pieces overlap.
769 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
770 if (!P1.isBitPiece() || !P2.isBitPiece())
772 unsigned l1 = P1.getBitPieceOffset();
773 unsigned l2 = P2.getBitPieceOffset();
774 unsigned r1 = l1 + P1.getBitPieceSize();
775 unsigned r2 = l2 + P2.getBitPieceSize();
776 // True where [l1,r1[ and [r1,r2[ overlap.
777 return (l1 < r2) && (l2 < r1);
780 /// Build the location list for all DBG_VALUEs in the function that
781 /// describe the same variable. If the ranges of several independent
782 /// pieces of the same variable overlap partially, split them up and
783 /// combine the ranges. The resulting DebugLocEntries are will have
784 /// strict monotonically increasing begin addresses and will never
789 // Ranges History [var, loc, piece ofs size]
790 // 0 | [x, (reg0, piece 0, 32)]
791 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
793 // 3 | [clobber reg0]
794 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of
799 // [0-1] [x, (reg0, piece 0, 32)]
800 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
801 // [3-4] [x, (reg1, piece 32, 32)]
802 // [4- ] [x, (mem, piece 0, 64)]
804 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
805 const DbgValueHistoryMap::InstrRanges &Ranges) {
806 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
808 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
809 const MachineInstr *Begin = I->first;
810 const MachineInstr *End = I->second;
811 assert(Begin->isDebugValue() && "Invalid History entry");
813 // Check if a variable is inaccessible in this range.
814 if (Begin->getNumOperands() > 1 &&
815 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
820 // If this piece overlaps with any open ranges, truncate them.
821 DIExpression DIExpr = Begin->getDebugExpression();
822 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
823 [&](DebugLocEntry::Value R) {
824 return piecesOverlap(DIExpr, R.getExpression());
826 OpenRanges.erase(Last, OpenRanges.end());
828 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
829 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
831 const MCSymbol *EndLabel;
833 EndLabel = getLabelAfterInsn(End);
834 else if (std::next(I) == Ranges.end())
835 EndLabel = Asm->getFunctionEnd();
837 EndLabel = getLabelBeforeInsn(std::next(I)->first);
838 assert(EndLabel && "Forgot label after instruction ending a range!");
840 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
842 auto Value = getDebugLocValue(Begin);
843 DebugLocEntry Loc(StartLabel, EndLabel, Value);
844 bool couldMerge = false;
846 // If this is a piece, it may belong to the current DebugLocEntry.
847 if (DIExpr.isBitPiece()) {
848 // Add this value to the list of open ranges.
849 OpenRanges.push_back(Value);
851 // Attempt to add the piece to the last entry.
852 if (!DebugLoc.empty())
853 if (DebugLoc.back().MergeValues(Loc))
858 // Need to add a new DebugLocEntry. Add all values from still
859 // valid non-overlapping pieces.
860 if (OpenRanges.size())
861 Loc.addValues(OpenRanges);
863 DebugLoc.push_back(std::move(Loc));
866 // Attempt to coalesce the ranges of two otherwise identical
868 auto CurEntry = DebugLoc.rbegin();
869 auto PrevEntry = std::next(CurEntry);
870 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
874 dbgs() << CurEntry->getValues().size() << " Values:\n";
875 for (auto Value : CurEntry->getValues()) {
876 Value.getVariable()->dump();
877 Value.getExpression()->dump();
885 // Find variables for each lexical scope.
887 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
888 SmallPtrSetImpl<const MDNode *> &Processed) {
889 // Grab the variable info that was squirreled away in the MMI side-table.
890 collectVariableInfoFromMMITable(Processed);
892 for (const auto &I : DbgValues) {
893 DIVariable DV(I.first);
894 if (Processed.count(DV))
897 // Instruction ranges, specifying where DV is accessible.
898 const auto &Ranges = I.second;
902 LexicalScope *Scope = nullptr;
903 if (MDNode *IA = DV.getInlinedAt())
904 Scope = LScopes.findInlinedScope(DV.getContext(), IA);
906 Scope = LScopes.findLexicalScope(DV.getContext());
907 // If variable scope is not found then skip this variable.
911 Processed.insert(DV);
912 const MachineInstr *MInsn = Ranges.front().first;
913 assert(MInsn->isDebugValue() && "History must begin with debug value");
914 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
915 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
916 DbgVariable *RegVar = ConcreteVariables.back().get();
917 InfoHolder.addScopeVariable(Scope, RegVar);
919 // Check if the first DBG_VALUE is valid for the rest of the function.
920 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
923 // Handle multiple DBG_VALUE instructions describing one variable.
924 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
926 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
927 DebugLocList &LocList = DotDebugLocEntries.back();
930 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
932 // Build the location list for this variable.
933 buildLocationList(LocList.List, Ranges);
934 // Finalize the entry by lowering it into a DWARF bytestream.
935 for (auto &Entry : LocList.List)
936 Entry.finalize(*Asm, TypeIdentifierMap);
939 // Collect info for variables that were optimized out.
940 DIArray Variables = SP.getVariables();
941 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
942 DIVariable DV(Variables.getElement(i));
943 assert(DV.isVariable());
944 if (!Processed.insert(DV).second)
946 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
947 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
949 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
950 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
955 // Return Label preceding the instruction.
956 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
957 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
958 assert(Label && "Didn't insert label before instruction");
962 // Return Label immediately following the instruction.
963 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
964 return LabelsAfterInsn.lookup(MI);
967 // Process beginning of an instruction.
968 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
969 assert(CurMI == nullptr);
971 // Check if source location changes, but ignore DBG_VALUE locations.
972 if (!MI->isDebugValue()) {
973 DebugLoc DL = MI->getDebugLoc();
974 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
977 if (DL == PrologEndLoc) {
978 Flags |= DWARF2_FLAG_PROLOGUE_END;
979 PrologEndLoc = DebugLoc();
980 Flags |= DWARF2_FLAG_IS_STMT;
983 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
984 Flags |= DWARF2_FLAG_IS_STMT;
986 if (!DL.isUnknown()) {
987 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
988 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
990 recordSourceLine(0, 0, nullptr, 0);
994 // Insert labels where requested.
995 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
996 LabelsBeforeInsn.find(MI);
999 if (I == LabelsBeforeInsn.end())
1002 // Label already assigned.
1007 PrevLabel = MMI->getContext().CreateTempSymbol();
1008 Asm->OutStreamer.EmitLabel(PrevLabel);
1010 I->second = PrevLabel;
1013 // Process end of an instruction.
1014 void DwarfDebug::endInstruction() {
1015 assert(CurMI != nullptr);
1016 // Don't create a new label after DBG_VALUE instructions.
1017 // They don't generate code.
1018 if (!CurMI->isDebugValue())
1019 PrevLabel = nullptr;
1021 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1022 LabelsAfterInsn.find(CurMI);
1026 if (I == LabelsAfterInsn.end())
1029 // Label already assigned.
1033 // We need a label after this instruction.
1035 PrevLabel = MMI->getContext().CreateTempSymbol();
1036 Asm->OutStreamer.EmitLabel(PrevLabel);
1038 I->second = PrevLabel;
1041 // Each LexicalScope has first instruction and last instruction to mark
1042 // beginning and end of a scope respectively. Create an inverse map that list
1043 // scopes starts (and ends) with an instruction. One instruction may start (or
1044 // end) multiple scopes. Ignore scopes that are not reachable.
1045 void DwarfDebug::identifyScopeMarkers() {
1046 SmallVector<LexicalScope *, 4> WorkList;
1047 WorkList.push_back(LScopes.getCurrentFunctionScope());
1048 while (!WorkList.empty()) {
1049 LexicalScope *S = WorkList.pop_back_val();
1051 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1052 if (!Children.empty())
1053 WorkList.append(Children.begin(), Children.end());
1055 if (S->isAbstractScope())
1058 for (const InsnRange &R : S->getRanges()) {
1059 assert(R.first && "InsnRange does not have first instruction!");
1060 assert(R.second && "InsnRange does not have second instruction!");
1061 requestLabelBeforeInsn(R.first);
1062 requestLabelAfterInsn(R.second);
1067 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1068 // First known non-DBG_VALUE and non-frame setup location marks
1069 // the beginning of the function body.
1070 for (const auto &MBB : *MF)
1071 for (const auto &MI : MBB)
1072 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1073 !MI.getDebugLoc().isUnknown()) {
1074 // Did the target forget to set the FrameSetup flag for CFI insns?
1075 assert(!MI.isCFIInstruction() &&
1076 "First non-frame-setup instruction is a CFI instruction.");
1077 return MI.getDebugLoc();
1082 // Gather pre-function debug information. Assumes being called immediately
1083 // after the function entry point has been emitted.
1084 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1087 // If there's no debug info for the function we're not going to do anything.
1088 if (!MMI->hasDebugInfo())
1091 auto DI = FunctionDIs.find(MF->getFunction());
1092 if (DI == FunctionDIs.end())
1095 // Grab the lexical scopes for the function, if we don't have any of those
1096 // then we're not going to be able to do anything.
1097 LScopes.initialize(*MF);
1098 if (LScopes.empty())
1101 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1103 // Make sure that each lexical scope will have a begin/end label.
1104 identifyScopeMarkers();
1106 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1107 // belongs to so that we add to the correct per-cu line table in the
1109 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1110 // FnScope->getScopeNode() and DI->second should represent the same function,
1111 // though they may not be the same MDNode due to inline functions merged in
1112 // LTO where the debug info metadata still differs (either due to distinct
1113 // written differences - two versions of a linkonce_odr function
1114 // written/copied into two separate files, or some sub-optimal metadata that
1115 // isn't structurally identical (see: file path/name info from clang, which
1116 // includes the directory of the cpp file being built, even when the file name
1117 // is absolute (such as an <> lookup header)))
1118 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1119 assert(TheCU && "Unable to find compile unit!");
1120 if (Asm->OutStreamer.hasRawTextSupport())
1121 // Use a single line table if we are generating assembly.
1122 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1124 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1126 // Calculate history for local variables.
1127 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
1130 // Request labels for the full history.
1131 for (const auto &I : DbgValues) {
1132 const auto &Ranges = I.second;
1136 // The first mention of a function argument gets the CurrentFnBegin
1137 // label, so arguments are visible when breaking at function entry.
1138 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1139 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1140 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1141 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin();
1142 if (Ranges.front().first->getDebugExpression().isBitPiece()) {
1143 // Mark all non-overlapping initial pieces.
1144 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1145 DIExpression Piece = I->first->getDebugExpression();
1146 if (std::all_of(Ranges.begin(), I,
1147 [&](DbgValueHistoryMap::InstrRange Pred) {
1148 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1150 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
1157 for (const auto &Range : Ranges) {
1158 requestLabelBeforeInsn(Range.first);
1160 requestLabelAfterInsn(Range.second);
1164 PrevInstLoc = DebugLoc();
1165 PrevLabel = Asm->getFunctionBegin();
1167 // Record beginning of function.
1168 PrologEndLoc = findPrologueEndLoc(MF);
1169 if (!PrologEndLoc.isUnknown()) {
1170 DebugLoc FnStartDL =
1171 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1173 // We'd like to list the prologue as "not statements" but GDB behaves
1174 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1175 recordSourceLine(FnStartDL.getLine(), FnStartDL.getCol(),
1176 FnStartDL.getScope(MF->getFunction()->getContext()),
1177 DWARF2_FLAG_IS_STMT);
1181 // Gather and emit post-function debug information.
1182 void DwarfDebug::endFunction(const MachineFunction *MF) {
1183 assert(CurFn == MF &&
1184 "endFunction should be called with the same function as beginFunction");
1186 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1187 !FunctionDIs.count(MF->getFunction())) {
1188 // If we don't have a lexical scope for this function then there will
1189 // be a hole in the range information. Keep note of this by setting the
1190 // previously used section to nullptr.
1196 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1197 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1199 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1200 DISubprogram SP(FnScope->getScopeNode());
1201 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1203 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1204 collectVariableInfo(TheCU, SP, ProcessedVars);
1206 // Add the range of this function to the list of ranges for the CU.
1207 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd()));
1209 // Under -gmlt, skip building the subprogram if there are no inlined
1210 // subroutines inside it.
1211 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1212 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1213 assert(InfoHolder.getScopeVariables().empty());
1214 assert(DbgValues.empty());
1215 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1216 // by a -gmlt CU. Add a test and remove this assertion.
1217 assert(AbstractVariables.empty());
1218 LabelsBeforeInsn.clear();
1219 LabelsAfterInsn.clear();
1220 PrevLabel = nullptr;
1226 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1228 // Construct abstract scopes.
1229 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1230 DISubprogram SP(AScope->getScopeNode());
1231 assert(SP.isSubprogram());
1232 // Collect info for variables that were optimized out.
1233 DIArray Variables = SP.getVariables();
1234 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1235 DIVariable DV(Variables.getElement(i));
1236 assert(DV && DV.isVariable());
1237 if (!ProcessedVars.insert(DV).second)
1239 ensureAbstractVariableIsCreated(DV, DV.getContext());
1240 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1241 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1243 constructAbstractSubprogramScopeDIE(AScope);
1246 TheCU.constructSubprogramScopeDIE(FnScope);
1247 if (auto *SkelCU = TheCU.getSkeleton())
1248 if (!LScopes.getAbstractScopesList().empty())
1249 SkelCU->constructSubprogramScopeDIE(FnScope);
1252 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1253 // DbgVariables except those that are also in AbstractVariables (since they
1254 // can be used cross-function)
1255 InfoHolder.getScopeVariables().clear();
1257 LabelsBeforeInsn.clear();
1258 LabelsAfterInsn.clear();
1259 PrevLabel = nullptr;
1263 // Register a source line with debug info. Returns the unique label that was
1264 // emitted and which provides correspondence to the source line list.
1265 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1270 unsigned Discriminator = 0;
1271 if (DIScope Scope = DIScope(S)) {
1272 assert(Scope.isScope());
1273 Fn = Scope.getFilename();
1274 Dir = Scope.getDirectory();
1275 if (Scope.isLexicalBlockFile())
1276 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1278 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1279 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1280 .getOrCreateSourceID(Fn, Dir);
1282 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1286 //===----------------------------------------------------------------------===//
1288 //===----------------------------------------------------------------------===//
1290 // Emit the debug info section.
1291 void DwarfDebug::emitDebugInfo() {
1292 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1293 Holder.emitUnits(/* UseOffsets */ false);
1296 // Emit the abbreviation section.
1297 void DwarfDebug::emitAbbreviations() {
1298 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1300 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1303 // Emit the last address of the section and the end of the line matrix.
1304 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1305 // Define last address of section.
1306 Asm->OutStreamer.AddComment("Extended Op");
1309 Asm->OutStreamer.AddComment("Op size");
1310 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1311 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1312 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1314 Asm->OutStreamer.AddComment("Section end label");
1316 Asm->OutStreamer.EmitSymbolValue(
1317 Asm->GetTempSymbol("section_end", SectionEnd),
1318 Asm->getDataLayout().getPointerSize());
1320 // Mark end of matrix.
1321 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1327 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1328 StringRef TableName) {
1329 Accel.FinalizeTable(Asm, TableName);
1330 Asm->OutStreamer.SwitchSection(Section);
1332 // Emit the full data.
1333 Accel.emit(Asm, Section->getBeginSymbol(), this);
1336 // Emit visible names into a hashed accelerator table section.
1337 void DwarfDebug::emitAccelNames() {
1338 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1342 // Emit objective C classes and categories into a hashed accelerator table
1344 void DwarfDebug::emitAccelObjC() {
1345 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1349 // Emit namespace dies into a hashed accelerator table.
1350 void DwarfDebug::emitAccelNamespaces() {
1351 emitAccel(AccelNamespace,
1352 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1356 // Emit type dies into a hashed accelerator table.
1357 void DwarfDebug::emitAccelTypes() {
1358 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1362 // Public name handling.
1363 // The format for the various pubnames:
1365 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1366 // for the DIE that is named.
1368 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1369 // into the CU and the index value is computed according to the type of value
1370 // for the DIE that is named.
1372 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1373 // it's the offset within the debug_info/debug_types dwo section, however, the
1374 // reference in the pubname header doesn't change.
1376 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1377 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1379 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1381 // We could have a specification DIE that has our most of our knowledge,
1382 // look for that now.
1383 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1385 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1386 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1387 Linkage = dwarf::GIEL_EXTERNAL;
1388 } else if (Die->findAttribute(dwarf::DW_AT_external))
1389 Linkage = dwarf::GIEL_EXTERNAL;
1391 switch (Die->getTag()) {
1392 case dwarf::DW_TAG_class_type:
1393 case dwarf::DW_TAG_structure_type:
1394 case dwarf::DW_TAG_union_type:
1395 case dwarf::DW_TAG_enumeration_type:
1396 return dwarf::PubIndexEntryDescriptor(
1397 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1398 ? dwarf::GIEL_STATIC
1399 : dwarf::GIEL_EXTERNAL);
1400 case dwarf::DW_TAG_typedef:
1401 case dwarf::DW_TAG_base_type:
1402 case dwarf::DW_TAG_subrange_type:
1403 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1404 case dwarf::DW_TAG_namespace:
1405 return dwarf::GIEK_TYPE;
1406 case dwarf::DW_TAG_subprogram:
1407 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1408 case dwarf::DW_TAG_variable:
1409 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1410 case dwarf::DW_TAG_enumerator:
1411 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1412 dwarf::GIEL_STATIC);
1414 return dwarf::GIEK_NONE;
1418 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1420 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1421 const MCSection *PSec =
1422 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1423 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1425 emitDebugPubSection(GnuStyle, PSec, "Names",
1426 &DwarfCompileUnit::getGlobalNames);
1429 void DwarfDebug::emitDebugPubSection(
1430 bool GnuStyle, const MCSection *PSec, StringRef Name,
1431 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1432 for (const auto &NU : CUMap) {
1433 DwarfCompileUnit *TheU = NU.second;
1435 const auto &Globals = (TheU->*Accessor)();
1437 if (Globals.empty())
1440 if (auto *Skeleton = TheU->getSkeleton())
1442 unsigned ID = TheU->getUniqueID();
1444 // Start the dwarf pubnames section.
1445 Asm->OutStreamer.SwitchSection(PSec);
1448 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1449 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1450 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1451 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1453 Asm->OutStreamer.EmitLabel(BeginLabel);
1455 Asm->OutStreamer.AddComment("DWARF Version");
1456 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1458 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1459 Asm->emitSectionOffset(TheU->getLabelBegin());
1461 Asm->OutStreamer.AddComment("Compilation Unit Length");
1462 Asm->EmitInt32(TheU->getLength());
1464 // Emit the pubnames for this compilation unit.
1465 for (const auto &GI : Globals) {
1466 const char *Name = GI.getKeyData();
1467 const DIE *Entity = GI.second;
1469 Asm->OutStreamer.AddComment("DIE offset");
1470 Asm->EmitInt32(Entity->getOffset());
1473 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1474 Asm->OutStreamer.AddComment(
1475 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1476 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1477 Asm->EmitInt8(Desc.toBits());
1480 Asm->OutStreamer.AddComment("External Name");
1481 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1484 Asm->OutStreamer.AddComment("End Mark");
1486 Asm->OutStreamer.EmitLabel(EndLabel);
1490 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1491 const MCSection *PSec =
1492 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1493 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1495 emitDebugPubSection(GnuStyle, PSec, "Types",
1496 &DwarfCompileUnit::getGlobalTypes);
1499 // Emit visible names into a debug str section.
1500 void DwarfDebug::emitDebugStr() {
1501 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1502 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1506 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1507 const DebugLocEntry &Entry) {
1508 auto Comment = Entry.getComments().begin();
1509 auto End = Entry.getComments().end();
1510 for (uint8_t Byte : Entry.getDWARFBytes())
1511 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : "");
1514 static void emitDebugLocValue(const AsmPrinter &AP,
1515 const DITypeIdentifierMap &TypeIdentifierMap,
1516 ByteStreamer &Streamer,
1517 const DebugLocEntry::Value &Value,
1518 unsigned PieceOffsetInBits) {
1519 DIVariable DV = Value.getVariable();
1520 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(),
1521 AP.getDwarfDebug()->getDwarfVersion(),
1524 if (Value.isInt()) {
1525 DIBasicType BTy(DV.getType().resolve(TypeIdentifierMap));
1526 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1527 BTy.getEncoding() == dwarf::DW_ATE_signed_char))
1528 DwarfExpr.AddSignedConstant(Value.getInt());
1530 DwarfExpr.AddUnsignedConstant(Value.getInt());
1531 } else if (Value.isLocation()) {
1532 MachineLocation Loc = Value.getLoc();
1533 DIExpression Expr = Value.getExpression();
1534 if (!Expr || (Expr.getNumElements() == 0))
1536 AP.EmitDwarfRegOp(Streamer, Loc);
1538 // Complex address entry.
1539 if (Loc.getOffset()) {
1540 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1541 DwarfExpr.AddExpression(Expr.begin(), Expr.end(), PieceOffsetInBits);
1543 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1547 // else ... ignore constant fp. There is not any good way to
1548 // to represent them here in dwarf.
1553 void DebugLocEntry::finalize(const AsmPrinter &AP,
1554 const DITypeIdentifierMap &TypeIdentifierMap) {
1555 BufferByteStreamer Streamer(DWARFBytes, Comments);
1556 const DebugLocEntry::Value Value = Values[0];
1557 if (Value.isBitPiece()) {
1558 // Emit all pieces that belong to the same variable and range.
1559 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1560 return P.isBitPiece();
1561 }) && "all values are expected to be pieces");
1562 assert(std::is_sorted(Values.begin(), Values.end()) &&
1563 "pieces are expected to be sorted");
1565 unsigned Offset = 0;
1566 for (auto Piece : Values) {
1567 DIExpression Expr = Piece.getExpression();
1568 unsigned PieceOffset = Expr.getBitPieceOffset();
1569 unsigned PieceSize = Expr.getBitPieceSize();
1570 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1571 if (Offset < PieceOffset) {
1572 // The DWARF spec seriously mandates pieces with no locations for gaps.
1573 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(),
1574 AP.getDwarfDebug()->getDwarfVersion(),
1576 Expr.AddOpPiece(PieceOffset-Offset, 0);
1577 Offset += PieceOffset-Offset;
1579 Offset += PieceSize;
1582 DIVariable Var = Piece.getVariable();
1583 unsigned VarSize = Var.getSizeInBits(TypeIdentifierMap);
1584 assert(PieceSize+PieceOffset <= VarSize
1585 && "piece is larger than or outside of variable");
1586 assert(PieceSize != VarSize
1587 && "piece covers entire variable");
1589 emitDebugLocValue(AP, TypeIdentifierMap, Streamer, Piece, PieceOffset);
1592 assert(Values.size() == 1 && "only pieces may have >1 value");
1593 emitDebugLocValue(AP, TypeIdentifierMap, Streamer, Value, 0);
1598 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1599 Asm->OutStreamer.AddComment("Loc expr size");
1600 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1601 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1602 Asm->EmitLabelDifference(end, begin, 2);
1603 Asm->OutStreamer.EmitLabel(begin);
1605 APByteStreamer Streamer(*Asm);
1606 emitDebugLocEntry(Streamer, Entry);
1608 Asm->OutStreamer.EmitLabel(end);
1611 // Emit locations into the debug loc section.
1612 void DwarfDebug::emitDebugLoc() {
1613 // Start the dwarf loc section.
1614 Asm->OutStreamer.SwitchSection(
1615 Asm->getObjFileLowering().getDwarfLocSection());
1616 unsigned char Size = Asm->getDataLayout().getPointerSize();
1617 for (const auto &DebugLoc : DotDebugLocEntries) {
1618 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1619 const DwarfCompileUnit *CU = DebugLoc.CU;
1620 for (const auto &Entry : DebugLoc.List) {
1621 // Set up the range. This range is relative to the entry point of the
1622 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1623 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1624 if (auto *Base = CU->getBaseAddress()) {
1625 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1626 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1628 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1629 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1632 emitDebugLocEntryLocation(Entry);
1634 Asm->OutStreamer.EmitIntValue(0, Size);
1635 Asm->OutStreamer.EmitIntValue(0, Size);
1639 void DwarfDebug::emitDebugLocDWO() {
1640 Asm->OutStreamer.SwitchSection(
1641 Asm->getObjFileLowering().getDwarfLocDWOSection());
1642 for (const auto &DebugLoc : DotDebugLocEntries) {
1643 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1644 for (const auto &Entry : DebugLoc.List) {
1645 // Just always use start_length for now - at least that's one address
1646 // rather than two. We could get fancier and try to, say, reuse an
1647 // address we know we've emitted elsewhere (the start of the function?
1648 // The start of the CU or CU subrange that encloses this range?)
1649 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1650 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1651 Asm->EmitULEB128(idx);
1652 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1654 emitDebugLocEntryLocation(Entry);
1656 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1661 const MCSymbol *Start, *End;
1664 // Emit a debug aranges section, containing a CU lookup for any
1665 // address we can tie back to a CU.
1666 void DwarfDebug::emitDebugARanges() {
1667 // Provides a unique id per text section.
1668 MapVector<const MCSection *, SmallVector<SymbolCU, 8>> SectionMap;
1670 // Filter labels by section.
1671 for (const SymbolCU &SCU : ArangeLabels) {
1672 if (SCU.Sym->isInSection()) {
1673 // Make a note of this symbol and it's section.
1674 const MCSection *Section = &SCU.Sym->getSection();
1675 if (!Section->getKind().isMetadata())
1676 SectionMap[Section].push_back(SCU);
1678 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1679 // appear in the output. This sucks as we rely on sections to build
1680 // arange spans. We can do it without, but it's icky.
1681 SectionMap[nullptr].push_back(SCU);
1685 // Add terminating symbols for each section.
1687 for (const auto &I : SectionMap) {
1688 const MCSection *Section = I.first;
1689 MCSymbol *Sym = nullptr;
1692 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1693 // if we know the section name up-front. For user-created sections, the
1694 // resulting label may not be valid to use as a label. (section names can
1695 // use a greater set of characters on some systems)
1696 Sym = Asm->GetTempSymbol("debug_end", ID);
1697 Asm->OutStreamer.SwitchSection(Section);
1698 Asm->OutStreamer.EmitLabel(Sym);
1701 // Insert a final terminator.
1702 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1706 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans;
1708 for (auto &I : SectionMap) {
1709 const MCSection *Section = I.first;
1710 SmallVector<SymbolCU, 8> &List = I.second;
1711 if (List.size() < 2)
1714 // If we have no section (e.g. common), just write out
1715 // individual spans for each symbol.
1717 for (const SymbolCU &Cur : List) {
1719 Span.Start = Cur.Sym;
1722 Spans[Cur.CU].push_back(Span);
1727 // Sort the symbols by offset within the section.
1728 std::sort(List.begin(), List.end(),
1729 [&](const SymbolCU &A, const SymbolCU &B) {
1730 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1731 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1733 // Symbols with no order assigned should be placed at the end.
1734 // (e.g. section end labels)
1742 // Build spans between each label.
1743 const MCSymbol *StartSym = List[0].Sym;
1744 for (size_t n = 1, e = List.size(); n < e; n++) {
1745 const SymbolCU &Prev = List[n - 1];
1746 const SymbolCU &Cur = List[n];
1748 // Try and build the longest span we can within the same CU.
1749 if (Cur.CU != Prev.CU) {
1751 Span.Start = StartSym;
1753 Spans[Prev.CU].push_back(Span);
1759 // Start the dwarf aranges section.
1760 Asm->OutStreamer.SwitchSection(
1761 Asm->getObjFileLowering().getDwarfARangesSection());
1763 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1765 // Build a list of CUs used.
1766 std::vector<DwarfCompileUnit *> CUs;
1767 for (const auto &it : Spans) {
1768 DwarfCompileUnit *CU = it.first;
1772 // Sort the CU list (again, to ensure consistent output order).
1773 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1774 return A->getUniqueID() < B->getUniqueID();
1777 // Emit an arange table for each CU we used.
1778 for (DwarfCompileUnit *CU : CUs) {
1779 std::vector<ArangeSpan> &List = Spans[CU];
1781 // Describe the skeleton CU's offset and length, not the dwo file's.
1782 if (auto *Skel = CU->getSkeleton())
1785 // Emit size of content not including length itself.
1786 unsigned ContentSize =
1787 sizeof(int16_t) + // DWARF ARange version number
1788 sizeof(int32_t) + // Offset of CU in the .debug_info section
1789 sizeof(int8_t) + // Pointer Size (in bytes)
1790 sizeof(int8_t); // Segment Size (in bytes)
1792 unsigned TupleSize = PtrSize * 2;
1794 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1796 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1798 ContentSize += Padding;
1799 ContentSize += (List.size() + 1) * TupleSize;
1801 // For each compile unit, write the list of spans it covers.
1802 Asm->OutStreamer.AddComment("Length of ARange Set");
1803 Asm->EmitInt32(ContentSize);
1804 Asm->OutStreamer.AddComment("DWARF Arange version number");
1805 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1806 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1807 Asm->emitSectionOffset(CU->getLabelBegin());
1808 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1809 Asm->EmitInt8(PtrSize);
1810 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1813 Asm->OutStreamer.EmitFill(Padding, 0xff);
1815 for (const ArangeSpan &Span : List) {
1816 Asm->EmitLabelReference(Span.Start, PtrSize);
1818 // Calculate the size as being from the span start to it's end.
1820 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1822 // For symbols without an end marker (e.g. common), we
1823 // write a single arange entry containing just that one symbol.
1824 uint64_t Size = SymSize[Span.Start];
1828 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1832 Asm->OutStreamer.AddComment("ARange terminator");
1833 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1834 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1838 // Emit visible names into a debug ranges section.
1839 void DwarfDebug::emitDebugRanges() {
1840 // Start the dwarf ranges section.
1841 Asm->OutStreamer.SwitchSection(
1842 Asm->getObjFileLowering().getDwarfRangesSection());
1844 // Size for our labels.
1845 unsigned char Size = Asm->getDataLayout().getPointerSize();
1847 // Grab the specific ranges for the compile units in the module.
1848 for (const auto &I : CUMap) {
1849 DwarfCompileUnit *TheCU = I.second;
1851 if (auto *Skel = TheCU->getSkeleton())
1854 // Iterate over the misc ranges for the compile units in the module.
1855 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1856 // Emit our symbol so we can find the beginning of the range.
1857 Asm->OutStreamer.EmitLabel(List.getSym());
1859 for (const RangeSpan &Range : List.getRanges()) {
1860 const MCSymbol *Begin = Range.getStart();
1861 const MCSymbol *End = Range.getEnd();
1862 assert(Begin && "Range without a begin symbol?");
1863 assert(End && "Range without an end symbol?");
1864 if (auto *Base = TheCU->getBaseAddress()) {
1865 Asm->EmitLabelDifference(Begin, Base, Size);
1866 Asm->EmitLabelDifference(End, Base, Size);
1868 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1869 Asm->OutStreamer.EmitSymbolValue(End, Size);
1873 // And terminate the list with two 0 values.
1874 Asm->OutStreamer.EmitIntValue(0, Size);
1875 Asm->OutStreamer.EmitIntValue(0, Size);
1880 // DWARF5 Experimental Separate Dwarf emitters.
1882 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
1883 std::unique_ptr<DwarfUnit> NewU) {
1884 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
1885 U.getCUNode().getSplitDebugFilename());
1887 if (!CompilationDir.empty())
1888 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
1890 addGnuPubAttributes(*NewU, Die);
1892 SkeletonHolder.addUnit(std::move(NewU));
1895 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
1896 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
1897 // DW_AT_addr_base, DW_AT_ranges_base.
1898 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
1900 auto OwnedUnit = make_unique<DwarfCompileUnit>(
1901 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
1902 DwarfCompileUnit &NewCU = *OwnedUnit;
1903 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection());
1905 NewCU.initStmtList();
1907 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
1912 // Emit the .debug_info.dwo section for separated dwarf. This contains the
1913 // compile units that would normally be in debug_info.
1914 void DwarfDebug::emitDebugInfoDWO() {
1915 assert(useSplitDwarf() && "No split dwarf debug info?");
1916 // Don't emit relocations into the dwo file.
1917 InfoHolder.emitUnits(/* UseOffsets */ true);
1920 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
1921 // abbreviations for the .debug_info.dwo section.
1922 void DwarfDebug::emitDebugAbbrevDWO() {
1923 assert(useSplitDwarf() && "No split dwarf?");
1924 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
1927 void DwarfDebug::emitDebugLineDWO() {
1928 assert(useSplitDwarf() && "No split dwarf?");
1929 Asm->OutStreamer.SwitchSection(
1930 Asm->getObjFileLowering().getDwarfLineDWOSection());
1931 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
1934 // Emit the .debug_str.dwo section for separated dwarf. This contains the
1935 // string section and is identical in format to traditional .debug_str
1937 void DwarfDebug::emitDebugStrDWO() {
1938 assert(useSplitDwarf() && "No split dwarf?");
1939 const MCSection *OffSec =
1940 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
1941 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
1945 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
1946 if (!useSplitDwarf())
1949 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
1950 return &SplitTypeUnitFileTable;
1953 static uint64_t makeTypeSignature(StringRef Identifier) {
1955 Hash.update(Identifier);
1956 // ... take the least significant 8 bytes and return those. Our MD5
1957 // implementation always returns its results in little endian, swap bytes
1959 MD5::MD5Result Result;
1961 return support::endian::read64le(Result + 8);
1964 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
1965 StringRef Identifier, DIE &RefDie,
1966 DICompositeType CTy) {
1967 // Fast path if we're building some type units and one has already used the
1968 // address pool we know we're going to throw away all this work anyway, so
1969 // don't bother building dependent types.
1970 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
1973 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
1975 CU.addDIETypeSignature(RefDie, *TU);
1979 bool TopLevelType = TypeUnitsUnderConstruction.empty();
1980 AddrPool.resetUsedFlag();
1982 auto OwnedUnit = make_unique<DwarfTypeUnit>(
1983 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
1984 this, &InfoHolder, getDwoLineTable(CU));
1985 DwarfTypeUnit &NewTU = *OwnedUnit;
1986 DIE &UnitDie = NewTU.getUnitDie();
1988 TypeUnitsUnderConstruction.push_back(
1989 std::make_pair(std::move(OwnedUnit), CTy));
1991 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
1994 uint64_t Signature = makeTypeSignature(Identifier);
1995 NewTU.setTypeSignature(Signature);
1997 if (useSplitDwarf())
1998 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2000 CU.applyStmtList(UnitDie);
2002 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2005 NewTU.setType(NewTU.createTypeDIE(CTy));
2008 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2009 TypeUnitsUnderConstruction.clear();
2011 // Types referencing entries in the address table cannot be placed in type
2013 if (AddrPool.hasBeenUsed()) {
2015 // Remove all the types built while building this type.
2016 // This is pessimistic as some of these types might not be dependent on
2017 // the type that used an address.
2018 for (const auto &TU : TypeUnitsToAdd)
2019 DwarfTypeUnits.erase(TU.second);
2021 // Construct this type in the CU directly.
2022 // This is inefficient because all the dependent types will be rebuilt
2023 // from scratch, including building them in type units, discovering that
2024 // they depend on addresses, throwing them out and rebuilding them.
2025 CU.constructTypeDIE(RefDie, CTy);
2029 // If the type wasn't dependent on fission addresses, finish adding the type
2030 // and all its dependent types.
2031 for (auto &TU : TypeUnitsToAdd)
2032 InfoHolder.addUnit(std::move(TU.first));
2034 CU.addDIETypeSignature(RefDie, NewTU);
2037 // Accelerator table mutators - add each name along with its companion
2038 // DIE to the proper table while ensuring that the name that we're going
2039 // to reference is in the string table. We do this since the names we
2040 // add may not only be identical to the names in the DIE.
2041 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2042 if (!useDwarfAccelTables())
2044 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2048 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2049 if (!useDwarfAccelTables())
2051 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2055 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2056 if (!useDwarfAccelTables())
2058 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2062 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2063 if (!useDwarfAccelTables())
2065 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),