1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfDebug.h"
16 #include "ByteStreamer.h"
17 #include "DwarfCompileUnit.h"
20 #include "DwarfUnit.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
56 #define DEBUG_TYPE "dwarfdebug"
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
74 cl::desc("Generate dwarf aranges"),
78 enum DefaultOnOff { Default, Enable, Disable };
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
108 //===----------------------------------------------------------------------===//
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
151 uint16_t tag = Ty.getTag();
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), FirstCU(nullptr), PrevLabel(nullptr),
173 GlobalRangeCount(0), InfoHolder(A, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
204 HasSplitDwarf = SplitDwarf == Enable;
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
209 HasDwarfPubSections = DwarfPubSections == Enable;
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
224 DwarfDebug::~DwarfDebug() { }
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
247 return Name.find(") ") != StringRef::npos;
250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
267 // Helper for sorting sections into a stable output order.
268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
281 addAccelName(SP.getName(), Die);
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
288 // If this is an Objective-C selector name add it to the ObjC accelerator
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
325 if (Ranges.size() > 1)
328 // We don't create a DIE if we have a single Range and the end label
330 return !getLabelAfterInsn(Ranges.front().second);
333 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
334 assert(Scope && Scope->getScopeNode());
335 assert(Scope->isAbstractScope());
336 assert(!Scope->getInlinedAt());
338 const MDNode *SP = Scope->getScopeNode();
340 DIE *&AbsDef = AbstractSPDies[SP];
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 DwarfCompileUnit &SPCU = *SPMap[SP];
350 AbsDef = &SPCU.constructAbstractSubprogramScopeDIE(Scope);
353 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
354 if (!GenerateGnuPubSections)
357 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
360 // Create new DwarfCompileUnit for the given metadata node with tag
361 // DW_TAG_compile_unit.
362 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
363 StringRef FN = DIUnit.getFilename();
364 CompilationDir = DIUnit.getDirectory();
366 auto OwnedUnit = make_unique<DwarfCompileUnit>(
367 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
368 DwarfCompileUnit &NewCU = *OwnedUnit;
369 DIE &Die = NewCU.getUnitDie();
370 InfoHolder.addUnit(std::move(OwnedUnit));
372 // LTO with assembly output shares a single line table amongst multiple CUs.
373 // To avoid the compilation directory being ambiguous, let the line table
374 // explicitly describe the directory of all files, never relying on the
375 // compilation directory.
376 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
377 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
378 NewCU.getUniqueID(), CompilationDir);
380 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
381 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
382 DIUnit.getLanguage());
383 NewCU.addString(Die, dwarf::DW_AT_name, FN);
385 if (!useSplitDwarf()) {
386 NewCU.initStmtList(DwarfLineSectionSym);
388 // If we're using split dwarf the compilation dir is going to be in the
389 // skeleton CU and so we don't need to duplicate it here.
390 if (!CompilationDir.empty())
391 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
393 addGnuPubAttributes(NewCU, Die);
396 if (DIUnit.isOptimized())
397 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
399 StringRef Flags = DIUnit.getFlags();
401 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
403 if (unsigned RVer = DIUnit.getRunTimeVersion())
404 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
405 dwarf::DW_FORM_data1, RVer);
410 if (useSplitDwarf()) {
411 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
412 DwarfInfoDWOSectionSym);
413 NewCU.setSkeleton(constructSkeletonCU(NewCU));
415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
416 DwarfInfoSectionSym);
418 CUMap.insert(std::make_pair(DIUnit, &NewCU));
419 CUDieMap.insert(std::make_pair(&Die, &NewCU));
423 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
425 DIImportedEntity Module(N);
426 assert(Module.Verify());
427 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
428 D->addChild(TheCU.constructImportedEntityDIE(Module));
431 // Emit all Dwarf sections that should come prior to the content. Create
432 // global DIEs and emit initial debug info sections. This is invoked by
433 // the target AsmPrinter.
434 void DwarfDebug::beginModule() {
435 if (DisableDebugInfoPrinting)
438 const Module *M = MMI->getModule();
440 FunctionDIs = makeSubprogramMap(*M);
442 // If module has named metadata anchors then use them, otherwise scan the
443 // module using debug info finder to collect debug info.
444 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
447 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
449 // Emit initial sections so we can reference labels later.
452 SingleCU = CU_Nodes->getNumOperands() == 1;
454 for (MDNode *N : CU_Nodes->operands()) {
455 DICompileUnit CUNode(N);
456 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
457 DIArray ImportedEntities = CUNode.getImportedEntities();
458 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
459 ScopesWithImportedEntities.push_back(std::make_pair(
460 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
461 ImportedEntities.getElement(i)));
462 std::sort(ScopesWithImportedEntities.begin(),
463 ScopesWithImportedEntities.end(), less_first());
464 DIArray GVs = CUNode.getGlobalVariables();
465 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
466 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
467 DIArray SPs = CUNode.getSubprograms();
468 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
469 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
470 DIArray EnumTypes = CUNode.getEnumTypes();
471 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
472 DIType Ty(EnumTypes.getElement(i));
473 // The enum types array by design contains pointers to
474 // MDNodes rather than DIRefs. Unique them here.
475 DIType UniqueTy(resolve(Ty.getRef()));
476 CU.getOrCreateTypeDIE(UniqueTy);
478 DIArray RetainedTypes = CUNode.getRetainedTypes();
479 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
480 DIType Ty(RetainedTypes.getElement(i));
481 // The retained types array by design contains pointers to
482 // MDNodes rather than DIRefs. Unique them here.
483 DIType UniqueTy(resolve(Ty.getRef()));
484 CU.getOrCreateTypeDIE(UniqueTy);
486 // Emit imported_modules last so that the relevant context is already
488 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
489 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
492 // Tell MMI that we have debug info.
493 MMI->setDebugInfoAvailability(true);
495 // Prime section data.
496 SectionMap[Asm->getObjFileLowering().getTextSection()];
499 void DwarfDebug::finishVariableDefinitions() {
500 for (const auto &Var : ConcreteVariables) {
501 DIE *VariableDie = Var->getDIE();
503 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
504 // in the ConcreteVariables list, rather than looking it up again here.
505 // DIE::getUnit isn't simple - it walks parent pointers, etc.
506 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
508 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
509 if (AbsVar && AbsVar->getDIE()) {
510 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
513 Unit->applyVariableAttributes(*Var, *VariableDie);
517 void DwarfDebug::finishSubprogramDefinitions() {
518 const Module *M = MMI->getModule();
520 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
521 for (MDNode *N : CU_Nodes->operands()) {
522 DICompileUnit TheCU(N);
523 // Construct subprogram DIE and add variables DIEs.
524 DwarfCompileUnit *SPCU =
525 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
526 DIArray Subprograms = TheCU.getSubprograms();
527 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
528 DISubprogram SP(Subprograms.getElement(i));
529 // Perhaps the subprogram is in another CU (such as due to comdat
530 // folding, etc), in which case ignore it here.
531 if (SPMap[SP] != SPCU)
533 DIE *D = SPCU->getDIE(SP);
534 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
536 // If this subprogram has an abstract definition, reference that
537 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
539 if (!D && TheCU.getEmissionKind() != DIBuilder::LineTablesOnly)
540 // Lazily construct the subprogram if we didn't see either concrete or
541 // inlined versions during codegen. (except in -gmlt ^ where we want
542 // to omit these entirely)
543 D = SPCU->getOrCreateSubprogramDIE(SP);
545 // And attach the attributes
546 SPCU->applySubprogramAttributesToDefinition(SP, *D);
553 // Collect info for variables that were optimized out.
554 void DwarfDebug::collectDeadVariables() {
555 const Module *M = MMI->getModule();
557 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
558 for (MDNode *N : CU_Nodes->operands()) {
559 DICompileUnit TheCU(N);
560 // Construct subprogram DIE and add variables DIEs.
561 DwarfCompileUnit *SPCU =
562 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
563 assert(SPCU && "Unable to find Compile Unit!");
564 DIArray Subprograms = TheCU.getSubprograms();
565 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
566 DISubprogram SP(Subprograms.getElement(i));
567 if (ProcessedSPNodes.count(SP) != 0)
569 assert(SP.isSubprogram() &&
570 "CU's subprogram list contains a non-subprogram");
571 assert(SP.isDefinition() &&
572 "CU's subprogram list contains a subprogram declaration");
573 DIArray Variables = SP.getVariables();
574 if (Variables.getNumElements() == 0)
577 DIE *SPDIE = AbstractSPDies.lookup(SP);
579 SPDIE = SPCU->getDIE(SP);
581 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
582 DIVariable DV(Variables.getElement(vi));
583 assert(DV.isVariable());
584 DbgVariable NewVar(DV, DIExpression(nullptr), this);
585 auto VariableDie = SPCU->constructVariableDIE(NewVar);
586 SPCU->applyVariableAttributes(NewVar, *VariableDie);
587 SPDIE->addChild(std::move(VariableDie));
594 void DwarfDebug::finalizeModuleInfo() {
595 finishSubprogramDefinitions();
597 finishVariableDefinitions();
599 // Collect info for variables that were optimized out.
600 collectDeadVariables();
602 // Handle anything that needs to be done on a per-unit basis after
603 // all other generation.
604 for (const auto &TheU : getUnits()) {
605 // Emit DW_AT_containing_type attribute to connect types with their
606 // vtable holding type.
607 TheU->constructContainingTypeDIEs();
609 // Add CU specific attributes if we need to add any.
610 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
611 // If we're splitting the dwarf out now that we've got the entire
612 // CU then add the dwo id to it.
613 DwarfCompileUnit *SkCU =
614 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
615 if (useSplitDwarf()) {
616 // Emit a unique identifier for this CU.
617 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
618 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
619 dwarf::DW_FORM_data8, ID);
620 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
621 dwarf::DW_FORM_data8, ID);
623 // We don't keep track of which addresses are used in which CU so this
624 // is a bit pessimistic under LTO.
625 if (!AddrPool.isEmpty())
626 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
627 DwarfAddrSectionSym, DwarfAddrSectionSym);
628 if (!TheU->getRangeLists().empty())
629 SkCU->addSectionLabel(
630 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
631 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
634 // If we have code split among multiple sections or non-contiguous
635 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
636 // remain in the .o file, otherwise add a DW_AT_low_pc.
637 // FIXME: We should use ranges allow reordering of code ala
638 // .subsections_via_symbols in mach-o. This would mean turning on
639 // ranges for all subprogram DIEs for mach-o.
640 DwarfCompileUnit &U =
641 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
642 unsigned NumRanges = TheU->getRanges().size();
645 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
646 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
647 DwarfDebugRangeSectionSym);
649 // A DW_AT_low_pc attribute may also be specified in combination with
650 // DW_AT_ranges to specify the default base address for use in
651 // location lists (see Section 2.6.2) and range lists (see Section
653 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
656 RangeSpan &Range = TheU->getRanges().back();
657 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
663 // Compute DIE offsets and sizes.
664 InfoHolder.computeSizeAndOffsets();
666 SkeletonHolder.computeSizeAndOffsets();
669 void DwarfDebug::endSections() {
670 // Filter labels by section.
671 for (const SymbolCU &SCU : ArangeLabels) {
672 if (SCU.Sym->isInSection()) {
673 // Make a note of this symbol and it's section.
674 const MCSection *Section = &SCU.Sym->getSection();
675 if (!Section->getKind().isMetadata())
676 SectionMap[Section].push_back(SCU);
678 // Some symbols (e.g. common/bss on mach-o) can have no section but still
679 // appear in the output. This sucks as we rely on sections to build
680 // arange spans. We can do it without, but it's icky.
681 SectionMap[nullptr].push_back(SCU);
685 // Build a list of sections used.
686 std::vector<const MCSection *> Sections;
687 for (const auto &it : SectionMap) {
688 const MCSection *Section = it.first;
689 Sections.push_back(Section);
692 // Sort the sections into order.
693 // This is only done to ensure consistent output order across different runs.
694 std::sort(Sections.begin(), Sections.end(), SectionSort);
696 // Add terminating symbols for each section.
697 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
698 const MCSection *Section = Sections[ID];
699 MCSymbol *Sym = nullptr;
702 // We can't call MCSection::getLabelEndName, as it's only safe to do so
703 // if we know the section name up-front. For user-created sections, the
704 // resulting label may not be valid to use as a label. (section names can
705 // use a greater set of characters on some systems)
706 Sym = Asm->GetTempSymbol("debug_end", ID);
707 Asm->OutStreamer.SwitchSection(Section);
708 Asm->OutStreamer.EmitLabel(Sym);
711 // Insert a final terminator.
712 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
716 // Emit all Dwarf sections that should come after the content.
717 void DwarfDebug::endModule() {
718 assert(CurFn == nullptr);
719 assert(CurMI == nullptr);
724 // End any existing sections.
725 // TODO: Does this need to happen?
728 // Finalize the debug info for the module.
729 finalizeModuleInfo();
733 // Emit all the DIEs into a debug info section.
736 // Corresponding abbreviations into a abbrev section.
739 // Emit info into a debug aranges section.
740 if (GenerateARangeSection)
743 // Emit info into a debug ranges section.
746 if (useSplitDwarf()) {
749 emitDebugAbbrevDWO();
752 // Emit DWO addresses.
753 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
755 // Emit info into a debug loc section.
758 // Emit info into the dwarf accelerator table sections.
759 if (useDwarfAccelTables()) {
762 emitAccelNamespaces();
766 // Emit the pubnames and pubtypes sections if requested.
767 if (HasDwarfPubSections) {
768 emitDebugPubNames(GenerateGnuPubSections);
769 emitDebugPubTypes(GenerateGnuPubSections);
774 AbstractVariables.clear();
776 // Reset these for the next Module if we have one.
780 // Find abstract variable, if any, associated with Var.
781 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
782 DIVariable &Cleansed) {
783 LLVMContext &Ctx = DV->getContext();
784 // More then one inlined variable corresponds to one abstract variable.
785 // FIXME: This duplication of variables when inlining should probably be
786 // removed. It's done to allow each DIVariable to describe its location
787 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
788 // make it accurate then remove this duplication/cleansing stuff.
789 Cleansed = cleanseInlinedVariable(DV, Ctx);
790 auto I = AbstractVariables.find(Cleansed);
791 if (I != AbstractVariables.end())
792 return I->second.get();
796 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
798 return getExistingAbstractVariable(DV, Cleansed);
801 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
802 LexicalScope *Scope) {
803 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
804 addScopeVariable(Scope, AbsDbgVariable.get());
805 AbstractVariables[Var] = std::move(AbsDbgVariable);
808 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
809 const MDNode *ScopeNode) {
810 DIVariable Cleansed = DV;
811 if (getExistingAbstractVariable(DV, Cleansed))
814 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
818 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
819 const MDNode *ScopeNode) {
820 DIVariable Cleansed = DV;
821 if (getExistingAbstractVariable(DV, Cleansed))
824 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
825 createAbstractVariable(Cleansed, Scope);
828 // If Var is a current function argument then add it to CurrentFnArguments list.
829 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
830 if (!LScopes.isCurrentFunctionScope(Scope))
832 DIVariable DV = Var->getVariable();
833 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
835 unsigned ArgNo = DV.getArgNumber();
839 size_t Size = CurrentFnArguments.size();
841 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
842 // llvm::Function argument size is not good indicator of how many
843 // arguments does the function have at source level.
845 CurrentFnArguments.resize(ArgNo * 2);
846 assert(!CurrentFnArguments[ArgNo - 1]);
847 CurrentFnArguments[ArgNo - 1] = Var;
851 // Collect variable information from side table maintained by MMI.
852 void DwarfDebug::collectVariableInfoFromMMITable(
853 SmallPtrSetImpl<const MDNode *> &Processed) {
854 for (const auto &VI : MMI->getVariableDbgInfo()) {
857 Processed.insert(VI.Var);
858 DIVariable DV(VI.Var);
859 DIExpression Expr(VI.Expr);
860 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
862 // If variable scope is not found then skip this variable.
866 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
867 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
868 DbgVariable *RegVar = ConcreteVariables.back().get();
869 RegVar->setFrameIndex(VI.Slot);
870 addScopeVariable(Scope, RegVar);
874 // Get .debug_loc entry for the instruction range starting at MI.
875 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
876 const MDNode *Expr = MI->getDebugExpression();
877 const MDNode *Var = MI->getDebugVariable();
879 assert(MI->getNumOperands() == 4);
880 if (MI->getOperand(0).isReg()) {
881 MachineLocation MLoc;
882 // If the second operand is an immediate, this is a
883 // register-indirect address.
884 if (!MI->getOperand(1).isImm())
885 MLoc.set(MI->getOperand(0).getReg());
887 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
888 return DebugLocEntry::Value(Var, Expr, MLoc);
890 if (MI->getOperand(0).isImm())
891 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
892 if (MI->getOperand(0).isFPImm())
893 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
894 if (MI->getOperand(0).isCImm())
895 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
897 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
900 /// Determine whether two variable pieces overlap.
901 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
902 if (!P1.isVariablePiece() || !P2.isVariablePiece())
904 unsigned l1 = P1.getPieceOffset();
905 unsigned l2 = P2.getPieceOffset();
906 unsigned r1 = l1 + P1.getPieceSize();
907 unsigned r2 = l2 + P2.getPieceSize();
908 // True where [l1,r1[ and [r1,r2[ overlap.
909 return (l1 < r2) && (l2 < r1);
912 /// Build the location list for all DBG_VALUEs in the function that
913 /// describe the same variable. If the ranges of several independent
914 /// pieces of the same variable overlap partially, split them up and
915 /// combine the ranges. The resulting DebugLocEntries are will have
916 /// strict monotonically increasing begin addresses and will never
921 // Ranges History [var, loc, piece ofs size]
922 // 0 | [x, (reg0, piece 0, 32)]
923 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
925 // 3 | [clobber reg0]
926 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
930 // [0-1] [x, (reg0, piece 0, 32)]
931 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
932 // [3-4] [x, (reg1, piece 32, 32)]
933 // [4- ] [x, (mem, piece 0, 64)]
935 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
936 const DbgValueHistoryMap::InstrRanges &Ranges) {
937 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
939 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
940 const MachineInstr *Begin = I->first;
941 const MachineInstr *End = I->second;
942 assert(Begin->isDebugValue() && "Invalid History entry");
944 // Check if a variable is inaccessible in this range.
945 if (Begin->getNumOperands() > 1 &&
946 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
951 // If this piece overlaps with any open ranges, truncate them.
952 DIExpression DIExpr = Begin->getDebugExpression();
953 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
954 [&](DebugLocEntry::Value R) {
955 return piecesOverlap(DIExpr, R.getExpression());
957 OpenRanges.erase(Last, OpenRanges.end());
959 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
960 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
962 const MCSymbol *EndLabel;
964 EndLabel = getLabelAfterInsn(End);
965 else if (std::next(I) == Ranges.end())
966 EndLabel = FunctionEndSym;
968 EndLabel = getLabelBeforeInsn(std::next(I)->first);
969 assert(EndLabel && "Forgot label after instruction ending a range!");
971 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
973 auto Value = getDebugLocValue(Begin);
974 DebugLocEntry Loc(StartLabel, EndLabel, Value);
975 bool couldMerge = false;
977 // If this is a piece, it may belong to the current DebugLocEntry.
978 if (DIExpr.isVariablePiece()) {
979 // Add this value to the list of open ranges.
980 OpenRanges.push_back(Value);
982 // Attempt to add the piece to the last entry.
983 if (!DebugLoc.empty())
984 if (DebugLoc.back().MergeValues(Loc))
989 // Need to add a new DebugLocEntry. Add all values from still
990 // valid non-overlapping pieces.
991 if (OpenRanges.size())
992 Loc.addValues(OpenRanges);
994 DebugLoc.push_back(std::move(Loc));
997 // Attempt to coalesce the ranges of two otherwise identical
999 auto CurEntry = DebugLoc.rbegin();
1000 auto PrevEntry = std::next(CurEntry);
1001 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
1002 DebugLoc.pop_back();
1005 dbgs() << CurEntry->getValues().size() << " Values:\n";
1006 for (auto Value : CurEntry->getValues()) {
1007 Value.getVariable()->dump();
1008 Value.getExpression()->dump();
1010 dbgs() << "-----\n";
1016 // Find variables for each lexical scope.
1018 DwarfDebug::collectVariableInfo(SmallPtrSetImpl<const MDNode *> &Processed) {
1019 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1020 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1022 // Grab the variable info that was squirreled away in the MMI side-table.
1023 collectVariableInfoFromMMITable(Processed);
1025 for (const auto &I : DbgValues) {
1026 DIVariable DV(I.first);
1027 if (Processed.count(DV))
1030 // Instruction ranges, specifying where DV is accessible.
1031 const auto &Ranges = I.second;
1035 LexicalScope *Scope = nullptr;
1036 if (MDNode *IA = DV.getInlinedAt()) {
1037 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1038 Scope = LScopes.findInlinedScope(DebugLoc::get(
1039 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1041 Scope = LScopes.findLexicalScope(DV.getContext());
1042 // If variable scope is not found then skip this variable.
1046 Processed.insert(DV);
1047 const MachineInstr *MInsn = Ranges.front().first;
1048 assert(MInsn->isDebugValue() && "History must begin with debug value");
1049 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1050 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
1051 DbgVariable *RegVar = ConcreteVariables.back().get();
1052 addScopeVariable(Scope, RegVar);
1054 // Check if the first DBG_VALUE is valid for the rest of the function.
1055 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1058 // Handle multiple DBG_VALUE instructions describing one variable.
1059 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1061 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1062 DebugLocList &LocList = DotDebugLocEntries.back();
1065 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1067 // Build the location list for this variable.
1068 buildLocationList(LocList.List, Ranges);
1071 // Collect info for variables that were optimized out.
1072 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1073 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1074 DIVariable DV(Variables.getElement(i));
1075 assert(DV.isVariable());
1076 if (!Processed.insert(DV))
1078 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1079 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1080 DIExpression NoExpr;
1081 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
1082 addScopeVariable(Scope, ConcreteVariables.back().get());
1087 // Return Label preceding the instruction.
1088 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1089 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1090 assert(Label && "Didn't insert label before instruction");
1094 // Return Label immediately following the instruction.
1095 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1096 return LabelsAfterInsn.lookup(MI);
1099 // Process beginning of an instruction.
1100 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1101 assert(CurMI == nullptr);
1103 // Check if source location changes, but ignore DBG_VALUE locations.
1104 if (!MI->isDebugValue()) {
1105 DebugLoc DL = MI->getDebugLoc();
1106 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1109 if (DL == PrologEndLoc) {
1110 Flags |= DWARF2_FLAG_PROLOGUE_END;
1111 PrologEndLoc = DebugLoc();
1113 if (PrologEndLoc.isUnknown())
1114 Flags |= DWARF2_FLAG_IS_STMT;
1116 if (!DL.isUnknown()) {
1117 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1118 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1120 recordSourceLine(0, 0, nullptr, 0);
1124 // Insert labels where requested.
1125 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1126 LabelsBeforeInsn.find(MI);
1129 if (I == LabelsBeforeInsn.end())
1132 // Label already assigned.
1137 PrevLabel = MMI->getContext().CreateTempSymbol();
1138 Asm->OutStreamer.EmitLabel(PrevLabel);
1140 I->second = PrevLabel;
1143 // Process end of an instruction.
1144 void DwarfDebug::endInstruction() {
1145 assert(CurMI != nullptr);
1146 // Don't create a new label after DBG_VALUE instructions.
1147 // They don't generate code.
1148 if (!CurMI->isDebugValue())
1149 PrevLabel = nullptr;
1151 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1152 LabelsAfterInsn.find(CurMI);
1156 if (I == LabelsAfterInsn.end())
1159 // Label already assigned.
1163 // We need a label after this instruction.
1165 PrevLabel = MMI->getContext().CreateTempSymbol();
1166 Asm->OutStreamer.EmitLabel(PrevLabel);
1168 I->second = PrevLabel;
1171 // Each LexicalScope has first instruction and last instruction to mark
1172 // beginning and end of a scope respectively. Create an inverse map that list
1173 // scopes starts (and ends) with an instruction. One instruction may start (or
1174 // end) multiple scopes. Ignore scopes that are not reachable.
1175 void DwarfDebug::identifyScopeMarkers() {
1176 SmallVector<LexicalScope *, 4> WorkList;
1177 WorkList.push_back(LScopes.getCurrentFunctionScope());
1178 while (!WorkList.empty()) {
1179 LexicalScope *S = WorkList.pop_back_val();
1181 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1182 if (!Children.empty())
1183 WorkList.append(Children.begin(), Children.end());
1185 if (S->isAbstractScope())
1188 for (const InsnRange &R : S->getRanges()) {
1189 assert(R.first && "InsnRange does not have first instruction!");
1190 assert(R.second && "InsnRange does not have second instruction!");
1191 requestLabelBeforeInsn(R.first);
1192 requestLabelAfterInsn(R.second);
1197 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1198 // First known non-DBG_VALUE and non-frame setup location marks
1199 // the beginning of the function body.
1200 for (const auto &MBB : *MF)
1201 for (const auto &MI : MBB)
1202 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1203 !MI.getDebugLoc().isUnknown())
1204 return MI.getDebugLoc();
1208 // Gather pre-function debug information. Assumes being called immediately
1209 // after the function entry point has been emitted.
1210 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1213 // If there's no debug info for the function we're not going to do anything.
1214 if (!MMI->hasDebugInfo())
1217 auto DI = FunctionDIs.find(MF->getFunction());
1218 if (DI == FunctionDIs.end())
1221 // Grab the lexical scopes for the function, if we don't have any of those
1222 // then we're not going to be able to do anything.
1223 LScopes.initialize(*MF);
1224 if (LScopes.empty())
1227 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1229 // Make sure that each lexical scope will have a begin/end label.
1230 identifyScopeMarkers();
1232 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1233 // belongs to so that we add to the correct per-cu line table in the
1235 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1236 // FnScope->getScopeNode() and DI->second should represent the same function,
1237 // though they may not be the same MDNode due to inline functions merged in
1238 // LTO where the debug info metadata still differs (either due to distinct
1239 // written differences - two versions of a linkonce_odr function
1240 // written/copied into two separate files, or some sub-optimal metadata that
1241 // isn't structurally identical (see: file path/name info from clang, which
1242 // includes the directory of the cpp file being built, even when the file name
1243 // is absolute (such as an <> lookup header)))
1244 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1245 assert(TheCU && "Unable to find compile unit!");
1246 if (Asm->OutStreamer.hasRawTextSupport())
1247 // Use a single line table if we are generating assembly.
1248 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1250 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1252 // Emit a label for the function so that we have a beginning address.
1253 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1254 // Assumes in correct section after the entry point.
1255 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1257 // Calculate history for local variables.
1258 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1261 // Request labels for the full history.
1262 for (const auto &I : DbgValues) {
1263 const auto &Ranges = I.second;
1267 // The first mention of a function argument gets the FunctionBeginSym
1268 // label, so arguments are visible when breaking at function entry.
1269 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1270 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1271 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1272 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1273 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1274 // Mark all non-overlapping initial pieces.
1275 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1276 DIExpression Piece = I->first->getDebugExpression();
1277 if (std::all_of(Ranges.begin(), I,
1278 [&](DbgValueHistoryMap::InstrRange Pred) {
1279 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1281 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1288 for (const auto &Range : Ranges) {
1289 requestLabelBeforeInsn(Range.first);
1291 requestLabelAfterInsn(Range.second);
1295 PrevInstLoc = DebugLoc();
1296 PrevLabel = FunctionBeginSym;
1298 // Record beginning of function.
1299 PrologEndLoc = findPrologueEndLoc(MF);
1300 if (!PrologEndLoc.isUnknown()) {
1301 DebugLoc FnStartDL =
1302 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1304 FnStartDL.getLine(), FnStartDL.getCol(),
1305 FnStartDL.getScope(MF->getFunction()->getContext()),
1306 // We'd like to list the prologue as "not statements" but GDB behaves
1307 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1308 DWARF2_FLAG_IS_STMT);
1312 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1313 if (addCurrentFnArgument(Var, LS))
1315 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1316 DIVariable DV = Var->getVariable();
1317 // Variables with positive arg numbers are parameters.
1318 if (unsigned ArgNum = DV.getArgNumber()) {
1319 // Keep all parameters in order at the start of the variable list to ensure
1320 // function types are correct (no out-of-order parameters)
1322 // This could be improved by only doing it for optimized builds (unoptimized
1323 // builds have the right order to begin with), searching from the back (this
1324 // would catch the unoptimized case quickly), or doing a binary search
1325 // rather than linear search.
1326 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1327 while (I != Vars.end()) {
1328 unsigned CurNum = (*I)->getVariable().getArgNumber();
1329 // A local (non-parameter) variable has been found, insert immediately
1333 // A later indexed parameter has been found, insert immediately before it.
1334 if (CurNum > ArgNum)
1338 Vars.insert(I, Var);
1342 Vars.push_back(Var);
1345 // Gather and emit post-function debug information.
1346 void DwarfDebug::endFunction(const MachineFunction *MF) {
1347 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1348 // though the beginFunction may not be called at all.
1349 // We should handle both cases.
1353 assert(CurFn == MF);
1354 assert(CurFn != nullptr);
1356 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1357 !FunctionDIs.count(MF->getFunction())) {
1358 // If we don't have a lexical scope for this function then there will
1359 // be a hole in the range information. Keep note of this by setting the
1360 // previously used section to nullptr.
1366 // Define end label for subprogram.
1367 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1368 // Assumes in correct section after the entry point.
1369 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1371 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1372 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1374 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1375 collectVariableInfo(ProcessedVars);
1377 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1378 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1380 // Add the range of this function to the list of ranges for the CU.
1381 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1383 // Under -gmlt, skip building the subprogram if there are no inlined
1384 // subroutines inside it.
1385 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1386 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1387 assert(ScopeVariables.empty());
1388 assert(CurrentFnArguments.empty());
1389 assert(DbgValues.empty());
1390 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1391 // by a -gmlt CU. Add a test and remove this assertion.
1392 assert(AbstractVariables.empty());
1393 LabelsBeforeInsn.clear();
1394 LabelsAfterInsn.clear();
1395 PrevLabel = nullptr;
1400 // Construct abstract scopes.
1401 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1402 DISubprogram SP(AScope->getScopeNode());
1403 assert(SP.isSubprogram());
1404 // Collect info for variables that were optimized out.
1405 DIArray Variables = SP.getVariables();
1406 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1407 DIVariable DV(Variables.getElement(i));
1408 assert(DV && DV.isVariable());
1409 if (!ProcessedVars.insert(DV))
1411 ensureAbstractVariableIsCreated(DV, DV.getContext());
1413 constructAbstractSubprogramScopeDIE(AScope);
1416 TheCU.constructSubprogramScopeDIE(FnScope);
1419 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1420 // DbgVariables except those that are also in AbstractVariables (since they
1421 // can be used cross-function)
1422 ScopeVariables.clear();
1423 CurrentFnArguments.clear();
1425 LabelsBeforeInsn.clear();
1426 LabelsAfterInsn.clear();
1427 PrevLabel = nullptr;
1431 // Register a source line with debug info. Returns the unique label that was
1432 // emitted and which provides correspondence to the source line list.
1433 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1438 unsigned Discriminator = 0;
1439 if (DIScope Scope = DIScope(S)) {
1440 assert(Scope.isScope());
1441 Fn = Scope.getFilename();
1442 Dir = Scope.getDirectory();
1443 if (Scope.isLexicalBlockFile())
1444 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1446 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1447 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1448 .getOrCreateSourceID(Fn, Dir);
1450 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1454 //===----------------------------------------------------------------------===//
1456 //===----------------------------------------------------------------------===//
1458 // Emit initial Dwarf sections with a label at the start of each one.
1459 void DwarfDebug::emitSectionLabels() {
1460 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1462 // Dwarf sections base addresses.
1463 DwarfInfoSectionSym =
1464 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1465 if (useSplitDwarf()) {
1466 DwarfInfoDWOSectionSym =
1467 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1468 DwarfTypesDWOSectionSym =
1469 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1471 DwarfAbbrevSectionSym =
1472 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1473 if (useSplitDwarf())
1474 DwarfAbbrevDWOSectionSym = emitSectionSym(
1475 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1476 if (GenerateARangeSection)
1477 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1479 DwarfLineSectionSym =
1480 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1481 if (GenerateGnuPubSections) {
1482 DwarfGnuPubNamesSectionSym =
1483 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1484 DwarfGnuPubTypesSectionSym =
1485 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1486 } else if (HasDwarfPubSections) {
1487 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1488 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1491 DwarfStrSectionSym =
1492 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1493 if (useSplitDwarf()) {
1494 DwarfStrDWOSectionSym =
1495 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1496 DwarfAddrSectionSym =
1497 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1498 DwarfDebugLocSectionSym =
1499 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1501 DwarfDebugLocSectionSym =
1502 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1503 DwarfDebugRangeSectionSym =
1504 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1507 // Recursively emits a debug information entry.
1508 void DwarfDebug::emitDIE(DIE &Die) {
1509 // Get the abbreviation for this DIE.
1510 const DIEAbbrev &Abbrev = Die.getAbbrev();
1512 // Emit the code (index) for the abbreviation.
1513 if (Asm->isVerbose())
1514 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1515 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1516 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1517 dwarf::TagString(Abbrev.getTag()));
1518 Asm->EmitULEB128(Abbrev.getNumber());
1520 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1521 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1523 // Emit the DIE attribute values.
1524 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1525 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1526 dwarf::Form Form = AbbrevData[i].getForm();
1527 assert(Form && "Too many attributes for DIE (check abbreviation)");
1529 if (Asm->isVerbose()) {
1530 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1531 if (Attr == dwarf::DW_AT_accessibility)
1532 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1533 cast<DIEInteger>(Values[i])->getValue()));
1536 // Emit an attribute using the defined form.
1537 Values[i]->EmitValue(Asm, Form);
1540 // Emit the DIE children if any.
1541 if (Abbrev.hasChildren()) {
1542 for (auto &Child : Die.getChildren())
1545 Asm->OutStreamer.AddComment("End Of Children Mark");
1550 // Emit the debug info section.
1551 void DwarfDebug::emitDebugInfo() {
1552 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1554 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1557 // Emit the abbreviation section.
1558 void DwarfDebug::emitAbbreviations() {
1559 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1561 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1564 // Emit the last address of the section and the end of the line matrix.
1565 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1566 // Define last address of section.
1567 Asm->OutStreamer.AddComment("Extended Op");
1570 Asm->OutStreamer.AddComment("Op size");
1571 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1572 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1573 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1575 Asm->OutStreamer.AddComment("Section end label");
1577 Asm->OutStreamer.EmitSymbolValue(
1578 Asm->GetTempSymbol("section_end", SectionEnd),
1579 Asm->getDataLayout().getPointerSize());
1581 // Mark end of matrix.
1582 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1588 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1589 StringRef TableName, StringRef SymName) {
1590 Accel.FinalizeTable(Asm, TableName);
1591 Asm->OutStreamer.SwitchSection(Section);
1592 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1593 Asm->OutStreamer.EmitLabel(SectionBegin);
1595 // Emit the full data.
1596 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1599 // Emit visible names into a hashed accelerator table section.
1600 void DwarfDebug::emitAccelNames() {
1601 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1602 "Names", "names_begin");
1605 // Emit objective C classes and categories into a hashed accelerator table
1607 void DwarfDebug::emitAccelObjC() {
1608 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1609 "ObjC", "objc_begin");
1612 // Emit namespace dies into a hashed accelerator table.
1613 void DwarfDebug::emitAccelNamespaces() {
1614 emitAccel(AccelNamespace,
1615 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1616 "namespac", "namespac_begin");
1619 // Emit type dies into a hashed accelerator table.
1620 void DwarfDebug::emitAccelTypes() {
1621 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1622 "types", "types_begin");
1625 // Public name handling.
1626 // The format for the various pubnames:
1628 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1629 // for the DIE that is named.
1631 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1632 // into the CU and the index value is computed according to the type of value
1633 // for the DIE that is named.
1635 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1636 // it's the offset within the debug_info/debug_types dwo section, however, the
1637 // reference in the pubname header doesn't change.
1639 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1640 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1642 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1644 // We could have a specification DIE that has our most of our knowledge,
1645 // look for that now.
1646 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1648 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1649 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1650 Linkage = dwarf::GIEL_EXTERNAL;
1651 } else if (Die->findAttribute(dwarf::DW_AT_external))
1652 Linkage = dwarf::GIEL_EXTERNAL;
1654 switch (Die->getTag()) {
1655 case dwarf::DW_TAG_class_type:
1656 case dwarf::DW_TAG_structure_type:
1657 case dwarf::DW_TAG_union_type:
1658 case dwarf::DW_TAG_enumeration_type:
1659 return dwarf::PubIndexEntryDescriptor(
1660 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1661 ? dwarf::GIEL_STATIC
1662 : dwarf::GIEL_EXTERNAL);
1663 case dwarf::DW_TAG_typedef:
1664 case dwarf::DW_TAG_base_type:
1665 case dwarf::DW_TAG_subrange_type:
1666 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1667 case dwarf::DW_TAG_namespace:
1668 return dwarf::GIEK_TYPE;
1669 case dwarf::DW_TAG_subprogram:
1670 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1671 case dwarf::DW_TAG_constant:
1672 case dwarf::DW_TAG_variable:
1673 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1674 case dwarf::DW_TAG_enumerator:
1675 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1676 dwarf::GIEL_STATIC);
1678 return dwarf::GIEK_NONE;
1682 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1684 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1685 const MCSection *PSec =
1686 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1687 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1689 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1692 void DwarfDebug::emitDebugPubSection(
1693 bool GnuStyle, const MCSection *PSec, StringRef Name,
1694 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1695 for (const auto &NU : CUMap) {
1696 DwarfCompileUnit *TheU = NU.second;
1698 const auto &Globals = (TheU->*Accessor)();
1700 if (Globals.empty())
1703 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1705 unsigned ID = TheU->getUniqueID();
1707 // Start the dwarf pubnames section.
1708 Asm->OutStreamer.SwitchSection(PSec);
1711 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1712 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1713 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1714 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1716 Asm->OutStreamer.EmitLabel(BeginLabel);
1718 Asm->OutStreamer.AddComment("DWARF Version");
1719 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1721 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1722 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1724 Asm->OutStreamer.AddComment("Compilation Unit Length");
1725 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1727 // Emit the pubnames for this compilation unit.
1728 for (const auto &GI : Globals) {
1729 const char *Name = GI.getKeyData();
1730 const DIE *Entity = GI.second;
1732 Asm->OutStreamer.AddComment("DIE offset");
1733 Asm->EmitInt32(Entity->getOffset());
1736 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1737 Asm->OutStreamer.AddComment(
1738 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1739 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1740 Asm->EmitInt8(Desc.toBits());
1743 Asm->OutStreamer.AddComment("External Name");
1744 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1747 Asm->OutStreamer.AddComment("End Mark");
1749 Asm->OutStreamer.EmitLabel(EndLabel);
1753 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1754 const MCSection *PSec =
1755 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1756 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1758 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1761 // Emit visible names into a debug str section.
1762 void DwarfDebug::emitDebugStr() {
1763 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1764 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1767 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1768 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1769 const DITypeIdentifierMap &Map,
1770 ArrayRef<DebugLocEntry::Value> Values) {
1771 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1772 return P.isVariablePiece();
1773 }) && "all values are expected to be pieces");
1774 assert(std::is_sorted(Values.begin(), Values.end()) &&
1775 "pieces are expected to be sorted");
1777 unsigned Offset = 0;
1778 for (auto Piece : Values) {
1779 DIExpression Expr = Piece.getExpression();
1780 unsigned PieceOffset = Expr.getPieceOffset();
1781 unsigned PieceSize = Expr.getPieceSize();
1782 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1783 if (Offset < PieceOffset) {
1784 // The DWARF spec seriously mandates pieces with no locations for gaps.
1785 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1786 Offset += PieceOffset-Offset;
1789 Offset += PieceSize;
1791 const unsigned SizeOfByte = 8;
1793 DIVariable Var = Piece.getVariable();
1794 assert(!Var.isIndirect() && "indirect address for piece");
1795 unsigned VarSize = Var.getSizeInBits(Map);
1796 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1797 && "piece is larger than or outside of variable");
1798 assert(PieceSize*SizeOfByte != VarSize
1799 && "piece covers entire variable");
1801 if (Piece.isLocation() && Piece.getLoc().isReg())
1802 Asm->EmitDwarfRegOpPiece(Streamer,
1804 PieceSize*SizeOfByte);
1806 emitDebugLocValue(Streamer, Piece);
1807 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1813 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1814 const DebugLocEntry &Entry) {
1815 const DebugLocEntry::Value Value = Entry.getValues()[0];
1816 if (Value.isVariablePiece())
1817 // Emit all pieces that belong to the same variable and range.
1818 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1820 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1821 emitDebugLocValue(Streamer, Value);
1824 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1825 const DebugLocEntry::Value &Value) {
1826 DIVariable DV = Value.getVariable();
1828 if (Value.isInt()) {
1829 DIBasicType BTy(resolve(DV.getType()));
1830 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1831 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1832 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1833 Streamer.EmitSLEB128(Value.getInt());
1835 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1836 Streamer.EmitULEB128(Value.getInt());
1838 } else if (Value.isLocation()) {
1839 MachineLocation Loc = Value.getLoc();
1840 DIExpression Expr = Value.getExpression();
1843 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1845 // Complex address entry.
1846 unsigned N = Expr.getNumElements();
1848 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1849 if (Loc.getOffset()) {
1851 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1852 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1853 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1854 Streamer.EmitSLEB128(Expr.getElement(1));
1856 // If first address element is OpPlus then emit
1857 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1858 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1859 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1863 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1866 // Emit remaining complex address elements.
1867 for (; i < N; ++i) {
1868 uint64_t Element = Expr.getElement(i);
1869 if (Element == dwarf::DW_OP_plus) {
1870 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1871 Streamer.EmitULEB128(Expr.getElement(++i));
1872 } else if (Element == dwarf::DW_OP_deref) {
1874 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1875 } else if (Element == dwarf::DW_OP_piece) {
1877 // handled in emitDebugLocEntry.
1879 llvm_unreachable("unknown Opcode found in complex address");
1883 // else ... ignore constant fp. There is not any good way to
1884 // to represent them here in dwarf.
1888 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1889 Asm->OutStreamer.AddComment("Loc expr size");
1890 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1891 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1892 Asm->EmitLabelDifference(end, begin, 2);
1893 Asm->OutStreamer.EmitLabel(begin);
1895 APByteStreamer Streamer(*Asm);
1896 emitDebugLocEntry(Streamer, Entry);
1898 Asm->OutStreamer.EmitLabel(end);
1901 // Emit locations into the debug loc section.
1902 void DwarfDebug::emitDebugLoc() {
1903 // Start the dwarf loc section.
1904 Asm->OutStreamer.SwitchSection(
1905 Asm->getObjFileLowering().getDwarfLocSection());
1906 unsigned char Size = Asm->getDataLayout().getPointerSize();
1907 for (const auto &DebugLoc : DotDebugLocEntries) {
1908 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1909 const DwarfCompileUnit *CU = DebugLoc.CU;
1910 assert(!CU->getRanges().empty());
1911 for (const auto &Entry : DebugLoc.List) {
1912 // Set up the range. This range is relative to the entry point of the
1913 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1914 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1915 if (CU->getRanges().size() == 1) {
1916 // Grab the begin symbol from the first range as our base.
1917 const MCSymbol *Base = CU->getRanges()[0].getStart();
1918 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1919 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1921 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1922 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1925 emitDebugLocEntryLocation(Entry);
1927 Asm->OutStreamer.EmitIntValue(0, Size);
1928 Asm->OutStreamer.EmitIntValue(0, Size);
1932 void DwarfDebug::emitDebugLocDWO() {
1933 Asm->OutStreamer.SwitchSection(
1934 Asm->getObjFileLowering().getDwarfLocDWOSection());
1935 for (const auto &DebugLoc : DotDebugLocEntries) {
1936 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1937 for (const auto &Entry : DebugLoc.List) {
1938 // Just always use start_length for now - at least that's one address
1939 // rather than two. We could get fancier and try to, say, reuse an
1940 // address we know we've emitted elsewhere (the start of the function?
1941 // The start of the CU or CU subrange that encloses this range?)
1942 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1943 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1944 Asm->EmitULEB128(idx);
1945 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1947 emitDebugLocEntryLocation(Entry);
1949 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1954 const MCSymbol *Start, *End;
1957 // Emit a debug aranges section, containing a CU lookup for any
1958 // address we can tie back to a CU.
1959 void DwarfDebug::emitDebugARanges() {
1960 // Start the dwarf aranges section.
1961 Asm->OutStreamer.SwitchSection(
1962 Asm->getObjFileLowering().getDwarfARangesSection());
1964 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1968 // Build a list of sections used.
1969 std::vector<const MCSection *> Sections;
1970 for (const auto &it : SectionMap) {
1971 const MCSection *Section = it.first;
1972 Sections.push_back(Section);
1975 // Sort the sections into order.
1976 // This is only done to ensure consistent output order across different runs.
1977 std::sort(Sections.begin(), Sections.end(), SectionSort);
1979 // Build a set of address spans, sorted by CU.
1980 for (const MCSection *Section : Sections) {
1981 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1982 if (List.size() < 2)
1985 // Sort the symbols by offset within the section.
1986 std::sort(List.begin(), List.end(),
1987 [&](const SymbolCU &A, const SymbolCU &B) {
1988 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1989 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1991 // Symbols with no order assigned should be placed at the end.
1992 // (e.g. section end labels)
2000 // If we have no section (e.g. common), just write out
2001 // individual spans for each symbol.
2003 for (const SymbolCU &Cur : List) {
2005 Span.Start = Cur.Sym;
2008 Spans[Cur.CU].push_back(Span);
2011 // Build spans between each label.
2012 const MCSymbol *StartSym = List[0].Sym;
2013 for (size_t n = 1, e = List.size(); n < e; n++) {
2014 const SymbolCU &Prev = List[n - 1];
2015 const SymbolCU &Cur = List[n];
2017 // Try and build the longest span we can within the same CU.
2018 if (Cur.CU != Prev.CU) {
2020 Span.Start = StartSym;
2022 Spans[Prev.CU].push_back(Span);
2029 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2031 // Build a list of CUs used.
2032 std::vector<DwarfCompileUnit *> CUs;
2033 for (const auto &it : Spans) {
2034 DwarfCompileUnit *CU = it.first;
2038 // Sort the CU list (again, to ensure consistent output order).
2039 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2040 return A->getUniqueID() < B->getUniqueID();
2043 // Emit an arange table for each CU we used.
2044 for (DwarfCompileUnit *CU : CUs) {
2045 std::vector<ArangeSpan> &List = Spans[CU];
2047 // Emit size of content not including length itself.
2048 unsigned ContentSize =
2049 sizeof(int16_t) + // DWARF ARange version number
2050 sizeof(int32_t) + // Offset of CU in the .debug_info section
2051 sizeof(int8_t) + // Pointer Size (in bytes)
2052 sizeof(int8_t); // Segment Size (in bytes)
2054 unsigned TupleSize = PtrSize * 2;
2056 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2058 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2060 ContentSize += Padding;
2061 ContentSize += (List.size() + 1) * TupleSize;
2063 // For each compile unit, write the list of spans it covers.
2064 Asm->OutStreamer.AddComment("Length of ARange Set");
2065 Asm->EmitInt32(ContentSize);
2066 Asm->OutStreamer.AddComment("DWARF Arange version number");
2067 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2068 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2069 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2070 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2071 Asm->EmitInt8(PtrSize);
2072 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2075 Asm->OutStreamer.EmitFill(Padding, 0xff);
2077 for (const ArangeSpan &Span : List) {
2078 Asm->EmitLabelReference(Span.Start, PtrSize);
2080 // Calculate the size as being from the span start to it's end.
2082 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2084 // For symbols without an end marker (e.g. common), we
2085 // write a single arange entry containing just that one symbol.
2086 uint64_t Size = SymSize[Span.Start];
2090 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2094 Asm->OutStreamer.AddComment("ARange terminator");
2095 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2096 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2100 // Emit visible names into a debug ranges section.
2101 void DwarfDebug::emitDebugRanges() {
2102 // Start the dwarf ranges section.
2103 Asm->OutStreamer.SwitchSection(
2104 Asm->getObjFileLowering().getDwarfRangesSection());
2106 // Size for our labels.
2107 unsigned char Size = Asm->getDataLayout().getPointerSize();
2109 // Grab the specific ranges for the compile units in the module.
2110 for (const auto &I : CUMap) {
2111 DwarfCompileUnit *TheCU = I.second;
2113 // Iterate over the misc ranges for the compile units in the module.
2114 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2115 // Emit our symbol so we can find the beginning of the range.
2116 Asm->OutStreamer.EmitLabel(List.getSym());
2118 for (const RangeSpan &Range : List.getRanges()) {
2119 const MCSymbol *Begin = Range.getStart();
2120 const MCSymbol *End = Range.getEnd();
2121 assert(Begin && "Range without a begin symbol?");
2122 assert(End && "Range without an end symbol?");
2123 if (TheCU->getRanges().size() == 1) {
2124 // Grab the begin symbol from the first range as our base.
2125 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2126 Asm->EmitLabelDifference(Begin, Base, Size);
2127 Asm->EmitLabelDifference(End, Base, Size);
2129 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2130 Asm->OutStreamer.EmitSymbolValue(End, Size);
2134 // And terminate the list with two 0 values.
2135 Asm->OutStreamer.EmitIntValue(0, Size);
2136 Asm->OutStreamer.EmitIntValue(0, Size);
2139 // Now emit a range for the CU itself.
2140 if (TheCU->getRanges().size() > 1) {
2141 Asm->OutStreamer.EmitLabel(
2142 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2143 for (const RangeSpan &Range : TheCU->getRanges()) {
2144 const MCSymbol *Begin = Range.getStart();
2145 const MCSymbol *End = Range.getEnd();
2146 assert(Begin && "Range without a begin symbol?");
2147 assert(End && "Range without an end symbol?");
2148 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2149 Asm->OutStreamer.EmitSymbolValue(End, Size);
2151 // And terminate the list with two 0 values.
2152 Asm->OutStreamer.EmitIntValue(0, Size);
2153 Asm->OutStreamer.EmitIntValue(0, Size);
2158 // DWARF5 Experimental Separate Dwarf emitters.
2160 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2161 std::unique_ptr<DwarfUnit> NewU) {
2162 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2163 U.getCUNode().getSplitDebugFilename());
2165 if (!CompilationDir.empty())
2166 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2168 addGnuPubAttributes(*NewU, Die);
2170 SkeletonHolder.addUnit(std::move(NewU));
2173 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2174 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2175 // DW_AT_addr_base, DW_AT_ranges_base.
2176 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2178 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2179 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2180 DwarfCompileUnit &NewCU = *OwnedUnit;
2181 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2182 DwarfInfoSectionSym);
2184 NewCU.initStmtList(DwarfLineSectionSym);
2186 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2191 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2192 // compile units that would normally be in debug_info.
2193 void DwarfDebug::emitDebugInfoDWO() {
2194 assert(useSplitDwarf() && "No split dwarf debug info?");
2195 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2196 // emit relocations into the dwo file.
2197 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2200 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2201 // abbreviations for the .debug_info.dwo section.
2202 void DwarfDebug::emitDebugAbbrevDWO() {
2203 assert(useSplitDwarf() && "No split dwarf?");
2204 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2207 void DwarfDebug::emitDebugLineDWO() {
2208 assert(useSplitDwarf() && "No split dwarf?");
2209 Asm->OutStreamer.SwitchSection(
2210 Asm->getObjFileLowering().getDwarfLineDWOSection());
2211 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2214 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2215 // string section and is identical in format to traditional .debug_str
2217 void DwarfDebug::emitDebugStrDWO() {
2218 assert(useSplitDwarf() && "No split dwarf?");
2219 const MCSection *OffSec =
2220 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2221 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2225 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2226 if (!useSplitDwarf())
2229 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2230 return &SplitTypeUnitFileTable;
2233 static uint64_t makeTypeSignature(StringRef Identifier) {
2235 Hash.update(Identifier);
2236 // ... take the least significant 8 bytes and return those. Our MD5
2237 // implementation always returns its results in little endian, swap bytes
2239 MD5::MD5Result Result;
2241 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2244 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2245 StringRef Identifier, DIE &RefDie,
2246 DICompositeType CTy) {
2247 // Fast path if we're building some type units and one has already used the
2248 // address pool we know we're going to throw away all this work anyway, so
2249 // don't bother building dependent types.
2250 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2253 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2255 CU.addDIETypeSignature(RefDie, *TU);
2259 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2260 AddrPool.resetUsedFlag();
2262 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2263 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2264 this, &InfoHolder, getDwoLineTable(CU));
2265 DwarfTypeUnit &NewTU = *OwnedUnit;
2266 DIE &UnitDie = NewTU.getUnitDie();
2268 TypeUnitsUnderConstruction.push_back(
2269 std::make_pair(std::move(OwnedUnit), CTy));
2271 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2274 uint64_t Signature = makeTypeSignature(Identifier);
2275 NewTU.setTypeSignature(Signature);
2277 if (useSplitDwarf())
2278 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2279 DwarfTypesDWOSectionSym);
2281 CU.applyStmtList(UnitDie);
2283 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2286 NewTU.setType(NewTU.createTypeDIE(CTy));
2289 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2290 TypeUnitsUnderConstruction.clear();
2292 // Types referencing entries in the address table cannot be placed in type
2294 if (AddrPool.hasBeenUsed()) {
2296 // Remove all the types built while building this type.
2297 // This is pessimistic as some of these types might not be dependent on
2298 // the type that used an address.
2299 for (const auto &TU : TypeUnitsToAdd)
2300 DwarfTypeUnits.erase(TU.second);
2302 // Construct this type in the CU directly.
2303 // This is inefficient because all the dependent types will be rebuilt
2304 // from scratch, including building them in type units, discovering that
2305 // they depend on addresses, throwing them out and rebuilding them.
2306 CU.constructTypeDIE(RefDie, CTy);
2310 // If the type wasn't dependent on fission addresses, finish adding the type
2311 // and all its dependent types.
2312 for (auto &TU : TypeUnitsToAdd)
2313 InfoHolder.addUnit(std::move(TU.first));
2315 CU.addDIETypeSignature(RefDie, NewTU);
2318 // Accelerator table mutators - add each name along with its companion
2319 // DIE to the proper table while ensuring that the name that we're going
2320 // to reference is in the string table. We do this since the names we
2321 // add may not only be identical to the names in the DIE.
2322 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2323 if (!useDwarfAccelTables())
2325 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2329 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2330 if (!useDwarfAccelTables())
2332 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2336 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2337 if (!useDwarfAccelTables())
2339 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2343 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2344 if (!useDwarfAccelTables())
2346 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),