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(DwarfCompileUnit &TheCU,
334 LexicalScope *Scope) {
335 assert(Scope && Scope->getScopeNode());
336 assert(Scope->isAbstractScope());
337 assert(!Scope->getInlinedAt());
339 DISubprogram SP(Scope->getScopeNode());
341 ProcessedSPNodes.insert(SP);
343 DIE *&AbsDef = AbstractSPDies[SP];
347 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
348 // was inlined from another compile unit.
349 DwarfCompileUnit &SPCU = *SPMap[SP];
352 // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
353 // the important distinction that the DIDescriptor is not associated with the
354 // DIE (since the DIDescriptor will be associated with the concrete DIE, if
355 // any). It could be refactored to some common utility function.
356 if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
357 ContextDIE = &SPCU.getUnitDie();
358 SPCU.getOrCreateSubprogramDIE(SPDecl);
360 ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
362 // Passing null as the associated DIDescriptor because the abstract definition
363 // shouldn't be found by lookup.
364 AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
366 SPCU.applySubprogramAttributesToDefinition(SP, *AbsDef);
368 if (TheCU.getCUNode().getEmissionKind() != DIBuilder::LineTablesOnly)
369 SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
370 if (DIE *ObjectPointer = SPCU.createAndAddScopeChildren(Scope, *AbsDef))
371 SPCU.addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
374 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
375 if (!GenerateGnuPubSections)
378 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
381 // Create new DwarfCompileUnit for the given metadata node with tag
382 // DW_TAG_compile_unit.
383 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
384 StringRef FN = DIUnit.getFilename();
385 CompilationDir = DIUnit.getDirectory();
387 auto OwnedUnit = make_unique<DwarfCompileUnit>(
388 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
389 DwarfCompileUnit &NewCU = *OwnedUnit;
390 DIE &Die = NewCU.getUnitDie();
391 InfoHolder.addUnit(std::move(OwnedUnit));
393 // LTO with assembly output shares a single line table amongst multiple CUs.
394 // To avoid the compilation directory being ambiguous, let the line table
395 // explicitly describe the directory of all files, never relying on the
396 // compilation directory.
397 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
398 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
399 NewCU.getUniqueID(), CompilationDir);
401 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
402 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
403 DIUnit.getLanguage());
404 NewCU.addString(Die, dwarf::DW_AT_name, FN);
406 if (!useSplitDwarf()) {
407 NewCU.initStmtList(DwarfLineSectionSym);
409 // If we're using split dwarf the compilation dir is going to be in the
410 // skeleton CU and so we don't need to duplicate it here.
411 if (!CompilationDir.empty())
412 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
414 addGnuPubAttributes(NewCU, Die);
417 if (DIUnit.isOptimized())
418 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
420 StringRef Flags = DIUnit.getFlags();
422 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
424 if (unsigned RVer = DIUnit.getRunTimeVersion())
425 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
426 dwarf::DW_FORM_data1, RVer);
431 if (useSplitDwarf()) {
432 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
433 DwarfInfoDWOSectionSym);
434 NewCU.setSkeleton(constructSkeletonCU(NewCU));
436 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
437 DwarfInfoSectionSym);
439 CUMap.insert(std::make_pair(DIUnit, &NewCU));
440 CUDieMap.insert(std::make_pair(&Die, &NewCU));
444 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
446 DIImportedEntity Module(N);
447 assert(Module.Verify());
448 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
449 D->addChild(TheCU.constructImportedEntityDIE(Module));
452 // Emit all Dwarf sections that should come prior to the content. Create
453 // global DIEs and emit initial debug info sections. This is invoked by
454 // the target AsmPrinter.
455 void DwarfDebug::beginModule() {
456 if (DisableDebugInfoPrinting)
459 const Module *M = MMI->getModule();
461 FunctionDIs = makeSubprogramMap(*M);
463 // If module has named metadata anchors then use them, otherwise scan the
464 // module using debug info finder to collect debug info.
465 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
468 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
470 // Emit initial sections so we can reference labels later.
473 SingleCU = CU_Nodes->getNumOperands() == 1;
475 for (MDNode *N : CU_Nodes->operands()) {
476 DICompileUnit CUNode(N);
477 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
478 DIArray ImportedEntities = CUNode.getImportedEntities();
479 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
480 ScopesWithImportedEntities.push_back(std::make_pair(
481 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
482 ImportedEntities.getElement(i)));
483 std::sort(ScopesWithImportedEntities.begin(),
484 ScopesWithImportedEntities.end(), less_first());
485 DIArray GVs = CUNode.getGlobalVariables();
486 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
487 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
488 DIArray SPs = CUNode.getSubprograms();
489 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
490 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
491 DIArray EnumTypes = CUNode.getEnumTypes();
492 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
493 DIType Ty(EnumTypes.getElement(i));
494 // The enum types array by design contains pointers to
495 // MDNodes rather than DIRefs. Unique them here.
496 DIType UniqueTy(resolve(Ty.getRef()));
497 CU.getOrCreateTypeDIE(UniqueTy);
499 DIArray RetainedTypes = CUNode.getRetainedTypes();
500 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
501 DIType Ty(RetainedTypes.getElement(i));
502 // The retained types array by design contains pointers to
503 // MDNodes rather than DIRefs. Unique them here.
504 DIType UniqueTy(resolve(Ty.getRef()));
505 CU.getOrCreateTypeDIE(UniqueTy);
507 // Emit imported_modules last so that the relevant context is already
509 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
510 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
513 // Tell MMI that we have debug info.
514 MMI->setDebugInfoAvailability(true);
516 // Prime section data.
517 SectionMap[Asm->getObjFileLowering().getTextSection()];
520 void DwarfDebug::finishVariableDefinitions() {
521 for (const auto &Var : ConcreteVariables) {
522 DIE *VariableDie = Var->getDIE();
524 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
525 // in the ConcreteVariables list, rather than looking it up again here.
526 // DIE::getUnit isn't simple - it walks parent pointers, etc.
527 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
529 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
530 if (AbsVar && AbsVar->getDIE()) {
531 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
534 Unit->applyVariableAttributes(*Var, *VariableDie);
538 void DwarfDebug::finishSubprogramDefinitions() {
539 const Module *M = MMI->getModule();
541 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
542 for (MDNode *N : CU_Nodes->operands()) {
543 DICompileUnit TheCU(N);
544 // Construct subprogram DIE and add variables DIEs.
545 DwarfCompileUnit *SPCU =
546 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
547 DIArray Subprograms = TheCU.getSubprograms();
548 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
549 DISubprogram SP(Subprograms.getElement(i));
550 // Perhaps the subprogram is in another CU (such as due to comdat
551 // folding, etc), in which case ignore it here.
552 if (SPMap[SP] != SPCU)
554 DIE *D = SPCU->getDIE(SP);
555 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
557 // If this subprogram has an abstract definition, reference that
558 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
560 if (!D && TheCU.getEmissionKind() != DIBuilder::LineTablesOnly)
561 // Lazily construct the subprogram if we didn't see either concrete or
562 // inlined versions during codegen. (except in -gmlt ^ where we want
563 // to omit these entirely)
564 D = SPCU->getOrCreateSubprogramDIE(SP);
566 // And attach the attributes
567 SPCU->applySubprogramAttributesToDefinition(SP, *D);
574 // Collect info for variables that were optimized out.
575 void DwarfDebug::collectDeadVariables() {
576 const Module *M = MMI->getModule();
578 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
579 for (MDNode *N : CU_Nodes->operands()) {
580 DICompileUnit TheCU(N);
581 // Construct subprogram DIE and add variables DIEs.
582 DwarfCompileUnit *SPCU =
583 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
584 assert(SPCU && "Unable to find Compile Unit!");
585 DIArray Subprograms = TheCU.getSubprograms();
586 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
587 DISubprogram SP(Subprograms.getElement(i));
588 if (ProcessedSPNodes.count(SP) != 0)
590 assert(SP.isSubprogram() &&
591 "CU's subprogram list contains a non-subprogram");
592 assert(SP.isDefinition() &&
593 "CU's subprogram list contains a subprogram declaration");
594 DIArray Variables = SP.getVariables();
595 if (Variables.getNumElements() == 0)
598 DIE *SPDIE = AbstractSPDies.lookup(SP);
600 SPDIE = SPCU->getDIE(SP);
602 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
603 DIVariable DV(Variables.getElement(vi));
604 assert(DV.isVariable());
605 DbgVariable NewVar(DV, DIExpression(nullptr), this);
606 auto VariableDie = SPCU->constructVariableDIE(NewVar);
607 SPCU->applyVariableAttributes(NewVar, *VariableDie);
608 SPDIE->addChild(std::move(VariableDie));
615 void DwarfDebug::finalizeModuleInfo() {
616 finishSubprogramDefinitions();
618 finishVariableDefinitions();
620 // Collect info for variables that were optimized out.
621 collectDeadVariables();
623 // Handle anything that needs to be done on a per-unit basis after
624 // all other generation.
625 for (const auto &TheU : getUnits()) {
626 // Emit DW_AT_containing_type attribute to connect types with their
627 // vtable holding type.
628 TheU->constructContainingTypeDIEs();
630 // Add CU specific attributes if we need to add any.
631 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
632 // If we're splitting the dwarf out now that we've got the entire
633 // CU then add the dwo id to it.
634 DwarfCompileUnit *SkCU =
635 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
636 if (useSplitDwarf()) {
637 // Emit a unique identifier for this CU.
638 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
639 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
640 dwarf::DW_FORM_data8, ID);
641 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
642 dwarf::DW_FORM_data8, ID);
644 // We don't keep track of which addresses are used in which CU so this
645 // is a bit pessimistic under LTO.
646 if (!AddrPool.isEmpty())
647 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
648 DwarfAddrSectionSym, DwarfAddrSectionSym);
649 if (!TheU->getRangeLists().empty())
650 SkCU->addSectionLabel(
651 SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
652 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
655 // If we have code split among multiple sections or non-contiguous
656 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
657 // remain in the .o file, otherwise add a DW_AT_low_pc.
658 // FIXME: We should use ranges allow reordering of code ala
659 // .subsections_via_symbols in mach-o. This would mean turning on
660 // ranges for all subprogram DIEs for mach-o.
661 DwarfCompileUnit &U =
662 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
663 unsigned NumRanges = TheU->getRanges().size();
666 U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_ranges,
667 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
668 DwarfDebugRangeSectionSym);
670 // A DW_AT_low_pc attribute may also be specified in combination with
671 // DW_AT_ranges to specify the default base address for use in
672 // location lists (see Section 2.6.2) and range lists (see Section
674 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
677 RangeSpan &Range = TheU->getRanges().back();
678 U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
684 // Compute DIE offsets and sizes.
685 InfoHolder.computeSizeAndOffsets();
687 SkeletonHolder.computeSizeAndOffsets();
690 void DwarfDebug::endSections() {
691 // Filter labels by section.
692 for (const SymbolCU &SCU : ArangeLabels) {
693 if (SCU.Sym->isInSection()) {
694 // Make a note of this symbol and it's section.
695 const MCSection *Section = &SCU.Sym->getSection();
696 if (!Section->getKind().isMetadata())
697 SectionMap[Section].push_back(SCU);
699 // Some symbols (e.g. common/bss on mach-o) can have no section but still
700 // appear in the output. This sucks as we rely on sections to build
701 // arange spans. We can do it without, but it's icky.
702 SectionMap[nullptr].push_back(SCU);
706 // Build a list of sections used.
707 std::vector<const MCSection *> Sections;
708 for (const auto &it : SectionMap) {
709 const MCSection *Section = it.first;
710 Sections.push_back(Section);
713 // Sort the sections into order.
714 // This is only done to ensure consistent output order across different runs.
715 std::sort(Sections.begin(), Sections.end(), SectionSort);
717 // Add terminating symbols for each section.
718 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
719 const MCSection *Section = Sections[ID];
720 MCSymbol *Sym = nullptr;
723 // We can't call MCSection::getLabelEndName, as it's only safe to do so
724 // if we know the section name up-front. For user-created sections, the
725 // resulting label may not be valid to use as a label. (section names can
726 // use a greater set of characters on some systems)
727 Sym = Asm->GetTempSymbol("debug_end", ID);
728 Asm->OutStreamer.SwitchSection(Section);
729 Asm->OutStreamer.EmitLabel(Sym);
732 // Insert a final terminator.
733 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
737 // Emit all Dwarf sections that should come after the content.
738 void DwarfDebug::endModule() {
739 assert(CurFn == nullptr);
740 assert(CurMI == nullptr);
745 // End any existing sections.
746 // TODO: Does this need to happen?
749 // Finalize the debug info for the module.
750 finalizeModuleInfo();
754 // Emit all the DIEs into a debug info section.
757 // Corresponding abbreviations into a abbrev section.
760 // Emit info into a debug aranges section.
761 if (GenerateARangeSection)
764 // Emit info into a debug ranges section.
767 if (useSplitDwarf()) {
770 emitDebugAbbrevDWO();
773 // Emit DWO addresses.
774 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
776 // Emit info into a debug loc section.
779 // Emit info into the dwarf accelerator table sections.
780 if (useDwarfAccelTables()) {
783 emitAccelNamespaces();
787 // Emit the pubnames and pubtypes sections if requested.
788 if (HasDwarfPubSections) {
789 emitDebugPubNames(GenerateGnuPubSections);
790 emitDebugPubTypes(GenerateGnuPubSections);
795 AbstractVariables.clear();
797 // Reset these for the next Module if we have one.
801 // Find abstract variable, if any, associated with Var.
802 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
803 DIVariable &Cleansed) {
804 LLVMContext &Ctx = DV->getContext();
805 // More then one inlined variable corresponds to one abstract variable.
806 // FIXME: This duplication of variables when inlining should probably be
807 // removed. It's done to allow each DIVariable to describe its location
808 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
809 // make it accurate then remove this duplication/cleansing stuff.
810 Cleansed = cleanseInlinedVariable(DV, Ctx);
811 auto I = AbstractVariables.find(Cleansed);
812 if (I != AbstractVariables.end())
813 return I->second.get();
817 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
819 return getExistingAbstractVariable(DV, Cleansed);
822 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
823 LexicalScope *Scope) {
824 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
825 addScopeVariable(Scope, AbsDbgVariable.get());
826 AbstractVariables[Var] = std::move(AbsDbgVariable);
829 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
830 const MDNode *ScopeNode) {
831 DIVariable Cleansed = DV;
832 if (getExistingAbstractVariable(DV, Cleansed))
835 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
839 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
840 const MDNode *ScopeNode) {
841 DIVariable Cleansed = DV;
842 if (getExistingAbstractVariable(DV, Cleansed))
845 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
846 createAbstractVariable(Cleansed, Scope);
849 // If Var is a current function argument then add it to CurrentFnArguments list.
850 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
851 if (!LScopes.isCurrentFunctionScope(Scope))
853 DIVariable DV = Var->getVariable();
854 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
856 unsigned ArgNo = DV.getArgNumber();
860 size_t Size = CurrentFnArguments.size();
862 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
863 // llvm::Function argument size is not good indicator of how many
864 // arguments does the function have at source level.
866 CurrentFnArguments.resize(ArgNo * 2);
867 assert(!CurrentFnArguments[ArgNo - 1]);
868 CurrentFnArguments[ArgNo - 1] = Var;
872 // Collect variable information from side table maintained by MMI.
873 void DwarfDebug::collectVariableInfoFromMMITable(
874 SmallPtrSetImpl<const MDNode *> &Processed) {
875 for (const auto &VI : MMI->getVariableDbgInfo()) {
878 Processed.insert(VI.Var);
879 DIVariable DV(VI.Var);
880 DIExpression Expr(VI.Expr);
881 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
883 // If variable scope is not found then skip this variable.
887 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
888 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
889 DbgVariable *RegVar = ConcreteVariables.back().get();
890 RegVar->setFrameIndex(VI.Slot);
891 addScopeVariable(Scope, RegVar);
895 // Get .debug_loc entry for the instruction range starting at MI.
896 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
897 const MDNode *Expr = MI->getDebugExpression();
898 const MDNode *Var = MI->getDebugVariable();
900 assert(MI->getNumOperands() == 4);
901 if (MI->getOperand(0).isReg()) {
902 MachineLocation MLoc;
903 // If the second operand is an immediate, this is a
904 // register-indirect address.
905 if (!MI->getOperand(1).isImm())
906 MLoc.set(MI->getOperand(0).getReg());
908 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
909 return DebugLocEntry::Value(Var, Expr, MLoc);
911 if (MI->getOperand(0).isImm())
912 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
913 if (MI->getOperand(0).isFPImm())
914 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
915 if (MI->getOperand(0).isCImm())
916 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
918 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
921 /// Determine whether two variable pieces overlap.
922 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
923 if (!P1.isVariablePiece() || !P2.isVariablePiece())
925 unsigned l1 = P1.getPieceOffset();
926 unsigned l2 = P2.getPieceOffset();
927 unsigned r1 = l1 + P1.getPieceSize();
928 unsigned r2 = l2 + P2.getPieceSize();
929 // True where [l1,r1[ and [r1,r2[ overlap.
930 return (l1 < r2) && (l2 < r1);
933 /// Build the location list for all DBG_VALUEs in the function that
934 /// describe the same variable. If the ranges of several independent
935 /// pieces of the same variable overlap partially, split them up and
936 /// combine the ranges. The resulting DebugLocEntries are will have
937 /// strict monotonically increasing begin addresses and will never
942 // Ranges History [var, loc, piece ofs size]
943 // 0 | [x, (reg0, piece 0, 32)]
944 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
946 // 3 | [clobber reg0]
947 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
951 // [0-1] [x, (reg0, piece 0, 32)]
952 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
953 // [3-4] [x, (reg1, piece 32, 32)]
954 // [4- ] [x, (mem, piece 0, 64)]
956 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
957 const DbgValueHistoryMap::InstrRanges &Ranges) {
958 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
960 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
961 const MachineInstr *Begin = I->first;
962 const MachineInstr *End = I->second;
963 assert(Begin->isDebugValue() && "Invalid History entry");
965 // Check if a variable is inaccessible in this range.
966 if (Begin->getNumOperands() > 1 &&
967 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
972 // If this piece overlaps with any open ranges, truncate them.
973 DIExpression DIExpr = Begin->getDebugExpression();
974 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
975 [&](DebugLocEntry::Value R) {
976 return piecesOverlap(DIExpr, R.getExpression());
978 OpenRanges.erase(Last, OpenRanges.end());
980 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
981 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
983 const MCSymbol *EndLabel;
985 EndLabel = getLabelAfterInsn(End);
986 else if (std::next(I) == Ranges.end())
987 EndLabel = FunctionEndSym;
989 EndLabel = getLabelBeforeInsn(std::next(I)->first);
990 assert(EndLabel && "Forgot label after instruction ending a range!");
992 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
994 auto Value = getDebugLocValue(Begin);
995 DebugLocEntry Loc(StartLabel, EndLabel, Value);
996 bool couldMerge = false;
998 // If this is a piece, it may belong to the current DebugLocEntry.
999 if (DIExpr.isVariablePiece()) {
1000 // Add this value to the list of open ranges.
1001 OpenRanges.push_back(Value);
1003 // Attempt to add the piece to the last entry.
1004 if (!DebugLoc.empty())
1005 if (DebugLoc.back().MergeValues(Loc))
1010 // Need to add a new DebugLocEntry. Add all values from still
1011 // valid non-overlapping pieces.
1012 if (OpenRanges.size())
1013 Loc.addValues(OpenRanges);
1015 DebugLoc.push_back(std::move(Loc));
1018 // Attempt to coalesce the ranges of two otherwise identical
1020 auto CurEntry = DebugLoc.rbegin();
1021 auto PrevEntry = std::next(CurEntry);
1022 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
1023 DebugLoc.pop_back();
1026 dbgs() << CurEntry->getValues().size() << " Values:\n";
1027 for (auto Value : CurEntry->getValues()) {
1028 Value.getVariable()->dump();
1029 Value.getExpression()->dump();
1031 dbgs() << "-----\n";
1037 // Find variables for each lexical scope.
1039 DwarfDebug::collectVariableInfo(SmallPtrSetImpl<const MDNode *> &Processed) {
1040 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1041 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1043 // Grab the variable info that was squirreled away in the MMI side-table.
1044 collectVariableInfoFromMMITable(Processed);
1046 for (const auto &I : DbgValues) {
1047 DIVariable DV(I.first);
1048 if (Processed.count(DV))
1051 // Instruction ranges, specifying where DV is accessible.
1052 const auto &Ranges = I.second;
1056 LexicalScope *Scope = nullptr;
1057 if (MDNode *IA = DV.getInlinedAt()) {
1058 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1059 Scope = LScopes.findInlinedScope(DebugLoc::get(
1060 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1062 Scope = LScopes.findLexicalScope(DV.getContext());
1063 // If variable scope is not found then skip this variable.
1067 Processed.insert(DV);
1068 const MachineInstr *MInsn = Ranges.front().first;
1069 assert(MInsn->isDebugValue() && "History must begin with debug value");
1070 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1071 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
1072 DbgVariable *RegVar = ConcreteVariables.back().get();
1073 addScopeVariable(Scope, RegVar);
1075 // Check if the first DBG_VALUE is valid for the rest of the function.
1076 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1079 // Handle multiple DBG_VALUE instructions describing one variable.
1080 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1082 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1083 DebugLocList &LocList = DotDebugLocEntries.back();
1086 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1088 // Build the location list for this variable.
1089 buildLocationList(LocList.List, Ranges);
1092 // Collect info for variables that were optimized out.
1093 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1094 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1095 DIVariable DV(Variables.getElement(i));
1096 assert(DV.isVariable());
1097 if (!Processed.insert(DV))
1099 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1100 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1101 DIExpression NoExpr;
1102 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
1103 addScopeVariable(Scope, ConcreteVariables.back().get());
1108 // Return Label preceding the instruction.
1109 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1110 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1111 assert(Label && "Didn't insert label before instruction");
1115 // Return Label immediately following the instruction.
1116 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1117 return LabelsAfterInsn.lookup(MI);
1120 // Process beginning of an instruction.
1121 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1122 assert(CurMI == nullptr);
1124 // Check if source location changes, but ignore DBG_VALUE locations.
1125 if (!MI->isDebugValue()) {
1126 DebugLoc DL = MI->getDebugLoc();
1127 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1130 if (DL == PrologEndLoc) {
1131 Flags |= DWARF2_FLAG_PROLOGUE_END;
1132 PrologEndLoc = DebugLoc();
1134 if (PrologEndLoc.isUnknown())
1135 Flags |= DWARF2_FLAG_IS_STMT;
1137 if (!DL.isUnknown()) {
1138 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1139 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1141 recordSourceLine(0, 0, nullptr, 0);
1145 // Insert labels where requested.
1146 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1147 LabelsBeforeInsn.find(MI);
1150 if (I == LabelsBeforeInsn.end())
1153 // Label already assigned.
1158 PrevLabel = MMI->getContext().CreateTempSymbol();
1159 Asm->OutStreamer.EmitLabel(PrevLabel);
1161 I->second = PrevLabel;
1164 // Process end of an instruction.
1165 void DwarfDebug::endInstruction() {
1166 assert(CurMI != nullptr);
1167 // Don't create a new label after DBG_VALUE instructions.
1168 // They don't generate code.
1169 if (!CurMI->isDebugValue())
1170 PrevLabel = nullptr;
1172 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1173 LabelsAfterInsn.find(CurMI);
1177 if (I == LabelsAfterInsn.end())
1180 // Label already assigned.
1184 // We need a label after this instruction.
1186 PrevLabel = MMI->getContext().CreateTempSymbol();
1187 Asm->OutStreamer.EmitLabel(PrevLabel);
1189 I->second = PrevLabel;
1192 // Each LexicalScope has first instruction and last instruction to mark
1193 // beginning and end of a scope respectively. Create an inverse map that list
1194 // scopes starts (and ends) with an instruction. One instruction may start (or
1195 // end) multiple scopes. Ignore scopes that are not reachable.
1196 void DwarfDebug::identifyScopeMarkers() {
1197 SmallVector<LexicalScope *, 4> WorkList;
1198 WorkList.push_back(LScopes.getCurrentFunctionScope());
1199 while (!WorkList.empty()) {
1200 LexicalScope *S = WorkList.pop_back_val();
1202 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1203 if (!Children.empty())
1204 WorkList.append(Children.begin(), Children.end());
1206 if (S->isAbstractScope())
1209 for (const InsnRange &R : S->getRanges()) {
1210 assert(R.first && "InsnRange does not have first instruction!");
1211 assert(R.second && "InsnRange does not have second instruction!");
1212 requestLabelBeforeInsn(R.first);
1213 requestLabelAfterInsn(R.second);
1218 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1219 // First known non-DBG_VALUE and non-frame setup location marks
1220 // the beginning of the function body.
1221 for (const auto &MBB : *MF)
1222 for (const auto &MI : MBB)
1223 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1224 !MI.getDebugLoc().isUnknown())
1225 return MI.getDebugLoc();
1229 // Gather pre-function debug information. Assumes being called immediately
1230 // after the function entry point has been emitted.
1231 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1234 // If there's no debug info for the function we're not going to do anything.
1235 if (!MMI->hasDebugInfo())
1238 auto DI = FunctionDIs.find(MF->getFunction());
1239 if (DI == FunctionDIs.end())
1242 // Grab the lexical scopes for the function, if we don't have any of those
1243 // then we're not going to be able to do anything.
1244 LScopes.initialize(*MF);
1245 if (LScopes.empty())
1248 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1250 // Make sure that each lexical scope will have a begin/end label.
1251 identifyScopeMarkers();
1253 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1254 // belongs to so that we add to the correct per-cu line table in the
1256 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1257 // FnScope->getScopeNode() and DI->second should represent the same function,
1258 // though they may not be the same MDNode due to inline functions merged in
1259 // LTO where the debug info metadata still differs (either due to distinct
1260 // written differences - two versions of a linkonce_odr function
1261 // written/copied into two separate files, or some sub-optimal metadata that
1262 // isn't structurally identical (see: file path/name info from clang, which
1263 // includes the directory of the cpp file being built, even when the file name
1264 // is absolute (such as an <> lookup header)))
1265 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1266 assert(TheCU && "Unable to find compile unit!");
1267 if (Asm->OutStreamer.hasRawTextSupport())
1268 // Use a single line table if we are generating assembly.
1269 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1271 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1273 // Emit a label for the function so that we have a beginning address.
1274 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1275 // Assumes in correct section after the entry point.
1276 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1278 // Calculate history for local variables.
1279 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1282 // Request labels for the full history.
1283 for (const auto &I : DbgValues) {
1284 const auto &Ranges = I.second;
1288 // The first mention of a function argument gets the FunctionBeginSym
1289 // label, so arguments are visible when breaking at function entry.
1290 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1291 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1292 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1293 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1294 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1295 // Mark all non-overlapping initial pieces.
1296 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1297 DIExpression Piece = I->first->getDebugExpression();
1298 if (std::all_of(Ranges.begin(), I,
1299 [&](DbgValueHistoryMap::InstrRange Pred) {
1300 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1302 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1309 for (const auto &Range : Ranges) {
1310 requestLabelBeforeInsn(Range.first);
1312 requestLabelAfterInsn(Range.second);
1316 PrevInstLoc = DebugLoc();
1317 PrevLabel = FunctionBeginSym;
1319 // Record beginning of function.
1320 PrologEndLoc = findPrologueEndLoc(MF);
1321 if (!PrologEndLoc.isUnknown()) {
1322 DebugLoc FnStartDL =
1323 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1325 FnStartDL.getLine(), FnStartDL.getCol(),
1326 FnStartDL.getScope(MF->getFunction()->getContext()),
1327 // We'd like to list the prologue as "not statements" but GDB behaves
1328 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1329 DWARF2_FLAG_IS_STMT);
1333 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1334 if (addCurrentFnArgument(Var, LS))
1336 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1337 DIVariable DV = Var->getVariable();
1338 // Variables with positive arg numbers are parameters.
1339 if (unsigned ArgNum = DV.getArgNumber()) {
1340 // Keep all parameters in order at the start of the variable list to ensure
1341 // function types are correct (no out-of-order parameters)
1343 // This could be improved by only doing it for optimized builds (unoptimized
1344 // builds have the right order to begin with), searching from the back (this
1345 // would catch the unoptimized case quickly), or doing a binary search
1346 // rather than linear search.
1347 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1348 while (I != Vars.end()) {
1349 unsigned CurNum = (*I)->getVariable().getArgNumber();
1350 // A local (non-parameter) variable has been found, insert immediately
1354 // A later indexed parameter has been found, insert immediately before it.
1355 if (CurNum > ArgNum)
1359 Vars.insert(I, Var);
1363 Vars.push_back(Var);
1366 // Gather and emit post-function debug information.
1367 void DwarfDebug::endFunction(const MachineFunction *MF) {
1368 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1369 // though the beginFunction may not be called at all.
1370 // We should handle both cases.
1374 assert(CurFn == MF);
1375 assert(CurFn != nullptr);
1377 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1378 !FunctionDIs.count(MF->getFunction())) {
1379 // If we don't have a lexical scope for this function then there will
1380 // be a hole in the range information. Keep note of this by setting the
1381 // previously used section to nullptr.
1387 // Define end label for subprogram.
1388 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1389 // Assumes in correct section after the entry point.
1390 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1392 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1393 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1395 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1396 collectVariableInfo(ProcessedVars);
1398 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1399 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1401 // Add the range of this function to the list of ranges for the CU.
1402 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1404 // Under -gmlt, skip building the subprogram if there are no inlined
1405 // subroutines inside it.
1406 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1407 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1408 assert(ScopeVariables.empty());
1409 assert(CurrentFnArguments.empty());
1410 assert(DbgValues.empty());
1411 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1412 // by a -gmlt CU. Add a test and remove this assertion.
1413 assert(AbstractVariables.empty());
1414 LabelsBeforeInsn.clear();
1415 LabelsAfterInsn.clear();
1416 PrevLabel = nullptr;
1421 // Construct abstract scopes.
1422 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1423 DISubprogram SP(AScope->getScopeNode());
1424 assert(SP.isSubprogram());
1425 // Collect info for variables that were optimized out.
1426 DIArray Variables = SP.getVariables();
1427 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1428 DIVariable DV(Variables.getElement(i));
1429 assert(DV && DV.isVariable());
1430 if (!ProcessedVars.insert(DV))
1432 ensureAbstractVariableIsCreated(DV, DV.getContext());
1434 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1437 TheCU.constructSubprogramScopeDIE(FnScope);
1440 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1441 // DbgVariables except those that are also in AbstractVariables (since they
1442 // can be used cross-function)
1443 ScopeVariables.clear();
1444 CurrentFnArguments.clear();
1446 LabelsBeforeInsn.clear();
1447 LabelsAfterInsn.clear();
1448 PrevLabel = nullptr;
1452 // Register a source line with debug info. Returns the unique label that was
1453 // emitted and which provides correspondence to the source line list.
1454 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1459 unsigned Discriminator = 0;
1460 if (DIScope Scope = DIScope(S)) {
1461 assert(Scope.isScope());
1462 Fn = Scope.getFilename();
1463 Dir = Scope.getDirectory();
1464 if (Scope.isLexicalBlockFile())
1465 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1467 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1468 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1469 .getOrCreateSourceID(Fn, Dir);
1471 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1475 //===----------------------------------------------------------------------===//
1477 //===----------------------------------------------------------------------===//
1479 // Emit initial Dwarf sections with a label at the start of each one.
1480 void DwarfDebug::emitSectionLabels() {
1481 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1483 // Dwarf sections base addresses.
1484 DwarfInfoSectionSym =
1485 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1486 if (useSplitDwarf()) {
1487 DwarfInfoDWOSectionSym =
1488 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1489 DwarfTypesDWOSectionSym =
1490 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1492 DwarfAbbrevSectionSym =
1493 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1494 if (useSplitDwarf())
1495 DwarfAbbrevDWOSectionSym = emitSectionSym(
1496 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1497 if (GenerateARangeSection)
1498 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1500 DwarfLineSectionSym =
1501 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1502 if (GenerateGnuPubSections) {
1503 DwarfGnuPubNamesSectionSym =
1504 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1505 DwarfGnuPubTypesSectionSym =
1506 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1507 } else if (HasDwarfPubSections) {
1508 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1509 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1512 DwarfStrSectionSym =
1513 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1514 if (useSplitDwarf()) {
1515 DwarfStrDWOSectionSym =
1516 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1517 DwarfAddrSectionSym =
1518 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1519 DwarfDebugLocSectionSym =
1520 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1522 DwarfDebugLocSectionSym =
1523 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1524 DwarfDebugRangeSectionSym =
1525 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1528 // Recursively emits a debug information entry.
1529 void DwarfDebug::emitDIE(DIE &Die) {
1530 // Get the abbreviation for this DIE.
1531 const DIEAbbrev &Abbrev = Die.getAbbrev();
1533 // Emit the code (index) for the abbreviation.
1534 if (Asm->isVerbose())
1535 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1536 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1537 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1538 dwarf::TagString(Abbrev.getTag()));
1539 Asm->EmitULEB128(Abbrev.getNumber());
1541 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1542 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1544 // Emit the DIE attribute values.
1545 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1546 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1547 dwarf::Form Form = AbbrevData[i].getForm();
1548 assert(Form && "Too many attributes for DIE (check abbreviation)");
1550 if (Asm->isVerbose()) {
1551 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1552 if (Attr == dwarf::DW_AT_accessibility)
1553 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1554 cast<DIEInteger>(Values[i])->getValue()));
1557 // Emit an attribute using the defined form.
1558 Values[i]->EmitValue(Asm, Form);
1561 // Emit the DIE children if any.
1562 if (Abbrev.hasChildren()) {
1563 for (auto &Child : Die.getChildren())
1566 Asm->OutStreamer.AddComment("End Of Children Mark");
1571 // Emit the debug info section.
1572 void DwarfDebug::emitDebugInfo() {
1573 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1575 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1578 // Emit the abbreviation section.
1579 void DwarfDebug::emitAbbreviations() {
1580 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1582 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1585 // Emit the last address of the section and the end of the line matrix.
1586 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1587 // Define last address of section.
1588 Asm->OutStreamer.AddComment("Extended Op");
1591 Asm->OutStreamer.AddComment("Op size");
1592 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1593 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1594 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1596 Asm->OutStreamer.AddComment("Section end label");
1598 Asm->OutStreamer.EmitSymbolValue(
1599 Asm->GetTempSymbol("section_end", SectionEnd),
1600 Asm->getDataLayout().getPointerSize());
1602 // Mark end of matrix.
1603 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1609 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1610 StringRef TableName, StringRef SymName) {
1611 Accel.FinalizeTable(Asm, TableName);
1612 Asm->OutStreamer.SwitchSection(Section);
1613 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1614 Asm->OutStreamer.EmitLabel(SectionBegin);
1616 // Emit the full data.
1617 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1620 // Emit visible names into a hashed accelerator table section.
1621 void DwarfDebug::emitAccelNames() {
1622 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1623 "Names", "names_begin");
1626 // Emit objective C classes and categories into a hashed accelerator table
1628 void DwarfDebug::emitAccelObjC() {
1629 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1630 "ObjC", "objc_begin");
1633 // Emit namespace dies into a hashed accelerator table.
1634 void DwarfDebug::emitAccelNamespaces() {
1635 emitAccel(AccelNamespace,
1636 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1637 "namespac", "namespac_begin");
1640 // Emit type dies into a hashed accelerator table.
1641 void DwarfDebug::emitAccelTypes() {
1642 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1643 "types", "types_begin");
1646 // Public name handling.
1647 // The format for the various pubnames:
1649 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1650 // for the DIE that is named.
1652 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1653 // into the CU and the index value is computed according to the type of value
1654 // for the DIE that is named.
1656 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1657 // it's the offset within the debug_info/debug_types dwo section, however, the
1658 // reference in the pubname header doesn't change.
1660 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1661 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1663 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1665 // We could have a specification DIE that has our most of our knowledge,
1666 // look for that now.
1667 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1669 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1670 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1671 Linkage = dwarf::GIEL_EXTERNAL;
1672 } else if (Die->findAttribute(dwarf::DW_AT_external))
1673 Linkage = dwarf::GIEL_EXTERNAL;
1675 switch (Die->getTag()) {
1676 case dwarf::DW_TAG_class_type:
1677 case dwarf::DW_TAG_structure_type:
1678 case dwarf::DW_TAG_union_type:
1679 case dwarf::DW_TAG_enumeration_type:
1680 return dwarf::PubIndexEntryDescriptor(
1681 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1682 ? dwarf::GIEL_STATIC
1683 : dwarf::GIEL_EXTERNAL);
1684 case dwarf::DW_TAG_typedef:
1685 case dwarf::DW_TAG_base_type:
1686 case dwarf::DW_TAG_subrange_type:
1687 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1688 case dwarf::DW_TAG_namespace:
1689 return dwarf::GIEK_TYPE;
1690 case dwarf::DW_TAG_subprogram:
1691 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1692 case dwarf::DW_TAG_constant:
1693 case dwarf::DW_TAG_variable:
1694 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1695 case dwarf::DW_TAG_enumerator:
1696 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1697 dwarf::GIEL_STATIC);
1699 return dwarf::GIEK_NONE;
1703 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1705 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1706 const MCSection *PSec =
1707 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1708 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1710 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1713 void DwarfDebug::emitDebugPubSection(
1714 bool GnuStyle, const MCSection *PSec, StringRef Name,
1715 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1716 for (const auto &NU : CUMap) {
1717 DwarfCompileUnit *TheU = NU.second;
1719 const auto &Globals = (TheU->*Accessor)();
1721 if (Globals.empty())
1724 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1726 unsigned ID = TheU->getUniqueID();
1728 // Start the dwarf pubnames section.
1729 Asm->OutStreamer.SwitchSection(PSec);
1732 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1733 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1734 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1735 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1737 Asm->OutStreamer.EmitLabel(BeginLabel);
1739 Asm->OutStreamer.AddComment("DWARF Version");
1740 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1742 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1743 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1745 Asm->OutStreamer.AddComment("Compilation Unit Length");
1746 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1748 // Emit the pubnames for this compilation unit.
1749 for (const auto &GI : Globals) {
1750 const char *Name = GI.getKeyData();
1751 const DIE *Entity = GI.second;
1753 Asm->OutStreamer.AddComment("DIE offset");
1754 Asm->EmitInt32(Entity->getOffset());
1757 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1758 Asm->OutStreamer.AddComment(
1759 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1760 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1761 Asm->EmitInt8(Desc.toBits());
1764 Asm->OutStreamer.AddComment("External Name");
1765 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1768 Asm->OutStreamer.AddComment("End Mark");
1770 Asm->OutStreamer.EmitLabel(EndLabel);
1774 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1775 const MCSection *PSec =
1776 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1777 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1779 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1782 // Emit visible names into a debug str section.
1783 void DwarfDebug::emitDebugStr() {
1784 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1785 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1788 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
1789 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1790 const DITypeIdentifierMap &Map,
1791 ArrayRef<DebugLocEntry::Value> Values) {
1792 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1793 return P.isVariablePiece();
1794 }) && "all values are expected to be pieces");
1795 assert(std::is_sorted(Values.begin(), Values.end()) &&
1796 "pieces are expected to be sorted");
1798 unsigned Offset = 0;
1799 for (auto Piece : Values) {
1800 DIExpression Expr = Piece.getExpression();
1801 unsigned PieceOffset = Expr.getPieceOffset();
1802 unsigned PieceSize = Expr.getPieceSize();
1803 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1804 if (Offset < PieceOffset) {
1805 // The DWARF spec seriously mandates pieces with no locations for gaps.
1806 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
1807 Offset += PieceOffset-Offset;
1810 Offset += PieceSize;
1812 const unsigned SizeOfByte = 8;
1814 DIVariable Var = Piece.getVariable();
1815 assert(!Var.isIndirect() && "indirect address for piece");
1816 unsigned VarSize = Var.getSizeInBits(Map);
1817 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1818 && "piece is larger than or outside of variable");
1819 assert(PieceSize*SizeOfByte != VarSize
1820 && "piece covers entire variable");
1822 if (Piece.isLocation() && Piece.getLoc().isReg())
1823 Asm->EmitDwarfRegOpPiece(Streamer,
1825 PieceSize*SizeOfByte);
1827 emitDebugLocValue(Streamer, Piece);
1828 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
1834 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1835 const DebugLocEntry &Entry) {
1836 const DebugLocEntry::Value Value = Entry.getValues()[0];
1837 if (Value.isVariablePiece())
1838 // Emit all pieces that belong to the same variable and range.
1839 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1841 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1842 emitDebugLocValue(Streamer, Value);
1845 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1846 const DebugLocEntry::Value &Value) {
1847 DIVariable DV = Value.getVariable();
1849 if (Value.isInt()) {
1850 DIBasicType BTy(resolve(DV.getType()));
1851 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1852 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1853 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1854 Streamer.EmitSLEB128(Value.getInt());
1856 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1857 Streamer.EmitULEB128(Value.getInt());
1859 } else if (Value.isLocation()) {
1860 MachineLocation Loc = Value.getLoc();
1861 DIExpression Expr = Value.getExpression();
1864 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1866 // Complex address entry.
1867 unsigned N = Expr.getNumElements();
1869 if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
1870 if (Loc.getOffset()) {
1872 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1873 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1874 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1875 Streamer.EmitSLEB128(Expr.getElement(1));
1877 // If first address element is OpPlus then emit
1878 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1879 MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
1880 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1884 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1887 // Emit remaining complex address elements.
1888 for (; i < N; ++i) {
1889 uint64_t Element = Expr.getElement(i);
1890 if (Element == dwarf::DW_OP_plus) {
1891 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1892 Streamer.EmitULEB128(Expr.getElement(++i));
1893 } else if (Element == dwarf::DW_OP_deref) {
1895 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1896 } else if (Element == dwarf::DW_OP_piece) {
1898 // handled in emitDebugLocEntry.
1900 llvm_unreachable("unknown Opcode found in complex address");
1904 // else ... ignore constant fp. There is not any good way to
1905 // to represent them here in dwarf.
1909 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1910 Asm->OutStreamer.AddComment("Loc expr size");
1911 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1912 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1913 Asm->EmitLabelDifference(end, begin, 2);
1914 Asm->OutStreamer.EmitLabel(begin);
1916 APByteStreamer Streamer(*Asm);
1917 emitDebugLocEntry(Streamer, Entry);
1919 Asm->OutStreamer.EmitLabel(end);
1922 // Emit locations into the debug loc section.
1923 void DwarfDebug::emitDebugLoc() {
1924 // Start the dwarf loc section.
1925 Asm->OutStreamer.SwitchSection(
1926 Asm->getObjFileLowering().getDwarfLocSection());
1927 unsigned char Size = Asm->getDataLayout().getPointerSize();
1928 for (const auto &DebugLoc : DotDebugLocEntries) {
1929 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1930 const DwarfCompileUnit *CU = DebugLoc.CU;
1931 assert(!CU->getRanges().empty());
1932 for (const auto &Entry : DebugLoc.List) {
1933 // Set up the range. This range is relative to the entry point of the
1934 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1935 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1936 if (CU->getRanges().size() == 1) {
1937 // Grab the begin symbol from the first range as our base.
1938 const MCSymbol *Base = CU->getRanges()[0].getStart();
1939 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1940 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1942 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1943 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1946 emitDebugLocEntryLocation(Entry);
1948 Asm->OutStreamer.EmitIntValue(0, Size);
1949 Asm->OutStreamer.EmitIntValue(0, Size);
1953 void DwarfDebug::emitDebugLocDWO() {
1954 Asm->OutStreamer.SwitchSection(
1955 Asm->getObjFileLowering().getDwarfLocDWOSection());
1956 for (const auto &DebugLoc : DotDebugLocEntries) {
1957 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1958 for (const auto &Entry : DebugLoc.List) {
1959 // Just always use start_length for now - at least that's one address
1960 // rather than two. We could get fancier and try to, say, reuse an
1961 // address we know we've emitted elsewhere (the start of the function?
1962 // The start of the CU or CU subrange that encloses this range?)
1963 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1964 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1965 Asm->EmitULEB128(idx);
1966 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1968 emitDebugLocEntryLocation(Entry);
1970 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1975 const MCSymbol *Start, *End;
1978 // Emit a debug aranges section, containing a CU lookup for any
1979 // address we can tie back to a CU.
1980 void DwarfDebug::emitDebugARanges() {
1981 // Start the dwarf aranges section.
1982 Asm->OutStreamer.SwitchSection(
1983 Asm->getObjFileLowering().getDwarfARangesSection());
1985 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1989 // Build a list of sections used.
1990 std::vector<const MCSection *> Sections;
1991 for (const auto &it : SectionMap) {
1992 const MCSection *Section = it.first;
1993 Sections.push_back(Section);
1996 // Sort the sections into order.
1997 // This is only done to ensure consistent output order across different runs.
1998 std::sort(Sections.begin(), Sections.end(), SectionSort);
2000 // Build a set of address spans, sorted by CU.
2001 for (const MCSection *Section : Sections) {
2002 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2003 if (List.size() < 2)
2006 // Sort the symbols by offset within the section.
2007 std::sort(List.begin(), List.end(),
2008 [&](const SymbolCU &A, const SymbolCU &B) {
2009 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2010 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2012 // Symbols with no order assigned should be placed at the end.
2013 // (e.g. section end labels)
2021 // If we have no section (e.g. common), just write out
2022 // individual spans for each symbol.
2024 for (const SymbolCU &Cur : List) {
2026 Span.Start = Cur.Sym;
2029 Spans[Cur.CU].push_back(Span);
2032 // Build spans between each label.
2033 const MCSymbol *StartSym = List[0].Sym;
2034 for (size_t n = 1, e = List.size(); n < e; n++) {
2035 const SymbolCU &Prev = List[n - 1];
2036 const SymbolCU &Cur = List[n];
2038 // Try and build the longest span we can within the same CU.
2039 if (Cur.CU != Prev.CU) {
2041 Span.Start = StartSym;
2043 Spans[Prev.CU].push_back(Span);
2050 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2052 // Build a list of CUs used.
2053 std::vector<DwarfCompileUnit *> CUs;
2054 for (const auto &it : Spans) {
2055 DwarfCompileUnit *CU = it.first;
2059 // Sort the CU list (again, to ensure consistent output order).
2060 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2061 return A->getUniqueID() < B->getUniqueID();
2064 // Emit an arange table for each CU we used.
2065 for (DwarfCompileUnit *CU : CUs) {
2066 std::vector<ArangeSpan> &List = Spans[CU];
2068 // Emit size of content not including length itself.
2069 unsigned ContentSize =
2070 sizeof(int16_t) + // DWARF ARange version number
2071 sizeof(int32_t) + // Offset of CU in the .debug_info section
2072 sizeof(int8_t) + // Pointer Size (in bytes)
2073 sizeof(int8_t); // Segment Size (in bytes)
2075 unsigned TupleSize = PtrSize * 2;
2077 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2079 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2081 ContentSize += Padding;
2082 ContentSize += (List.size() + 1) * TupleSize;
2084 // For each compile unit, write the list of spans it covers.
2085 Asm->OutStreamer.AddComment("Length of ARange Set");
2086 Asm->EmitInt32(ContentSize);
2087 Asm->OutStreamer.AddComment("DWARF Arange version number");
2088 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2089 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2090 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2091 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2092 Asm->EmitInt8(PtrSize);
2093 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2096 Asm->OutStreamer.EmitFill(Padding, 0xff);
2098 for (const ArangeSpan &Span : List) {
2099 Asm->EmitLabelReference(Span.Start, PtrSize);
2101 // Calculate the size as being from the span start to it's end.
2103 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2105 // For symbols without an end marker (e.g. common), we
2106 // write a single arange entry containing just that one symbol.
2107 uint64_t Size = SymSize[Span.Start];
2111 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2115 Asm->OutStreamer.AddComment("ARange terminator");
2116 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2117 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2121 // Emit visible names into a debug ranges section.
2122 void DwarfDebug::emitDebugRanges() {
2123 // Start the dwarf ranges section.
2124 Asm->OutStreamer.SwitchSection(
2125 Asm->getObjFileLowering().getDwarfRangesSection());
2127 // Size for our labels.
2128 unsigned char Size = Asm->getDataLayout().getPointerSize();
2130 // Grab the specific ranges for the compile units in the module.
2131 for (const auto &I : CUMap) {
2132 DwarfCompileUnit *TheCU = I.second;
2134 // Iterate over the misc ranges for the compile units in the module.
2135 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2136 // Emit our symbol so we can find the beginning of the range.
2137 Asm->OutStreamer.EmitLabel(List.getSym());
2139 for (const RangeSpan &Range : List.getRanges()) {
2140 const MCSymbol *Begin = Range.getStart();
2141 const MCSymbol *End = Range.getEnd();
2142 assert(Begin && "Range without a begin symbol?");
2143 assert(End && "Range without an end symbol?");
2144 if (TheCU->getRanges().size() == 1) {
2145 // Grab the begin symbol from the first range as our base.
2146 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2147 Asm->EmitLabelDifference(Begin, Base, Size);
2148 Asm->EmitLabelDifference(End, Base, Size);
2150 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2151 Asm->OutStreamer.EmitSymbolValue(End, Size);
2155 // And terminate the list with two 0 values.
2156 Asm->OutStreamer.EmitIntValue(0, Size);
2157 Asm->OutStreamer.EmitIntValue(0, Size);
2160 // Now emit a range for the CU itself.
2161 if (TheCU->getRanges().size() > 1) {
2162 Asm->OutStreamer.EmitLabel(
2163 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2164 for (const RangeSpan &Range : TheCU->getRanges()) {
2165 const MCSymbol *Begin = Range.getStart();
2166 const MCSymbol *End = Range.getEnd();
2167 assert(Begin && "Range without a begin symbol?");
2168 assert(End && "Range without an end symbol?");
2169 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2170 Asm->OutStreamer.EmitSymbolValue(End, Size);
2172 // And terminate the list with two 0 values.
2173 Asm->OutStreamer.EmitIntValue(0, Size);
2174 Asm->OutStreamer.EmitIntValue(0, Size);
2179 // DWARF5 Experimental Separate Dwarf emitters.
2181 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2182 std::unique_ptr<DwarfUnit> NewU) {
2183 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2184 U.getCUNode().getSplitDebugFilename());
2186 if (!CompilationDir.empty())
2187 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2189 addGnuPubAttributes(*NewU, Die);
2191 SkeletonHolder.addUnit(std::move(NewU));
2194 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2195 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2196 // DW_AT_addr_base, DW_AT_ranges_base.
2197 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2199 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2200 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2201 DwarfCompileUnit &NewCU = *OwnedUnit;
2202 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2203 DwarfInfoSectionSym);
2205 NewCU.initStmtList(DwarfLineSectionSym);
2207 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2212 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2213 // compile units that would normally be in debug_info.
2214 void DwarfDebug::emitDebugInfoDWO() {
2215 assert(useSplitDwarf() && "No split dwarf debug info?");
2216 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2217 // emit relocations into the dwo file.
2218 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2221 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2222 // abbreviations for the .debug_info.dwo section.
2223 void DwarfDebug::emitDebugAbbrevDWO() {
2224 assert(useSplitDwarf() && "No split dwarf?");
2225 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2228 void DwarfDebug::emitDebugLineDWO() {
2229 assert(useSplitDwarf() && "No split dwarf?");
2230 Asm->OutStreamer.SwitchSection(
2231 Asm->getObjFileLowering().getDwarfLineDWOSection());
2232 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2235 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2236 // string section and is identical in format to traditional .debug_str
2238 void DwarfDebug::emitDebugStrDWO() {
2239 assert(useSplitDwarf() && "No split dwarf?");
2240 const MCSection *OffSec =
2241 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2242 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2246 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2247 if (!useSplitDwarf())
2250 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2251 return &SplitTypeUnitFileTable;
2254 static uint64_t makeTypeSignature(StringRef Identifier) {
2256 Hash.update(Identifier);
2257 // ... take the least significant 8 bytes and return those. Our MD5
2258 // implementation always returns its results in little endian, swap bytes
2260 MD5::MD5Result Result;
2262 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2265 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2266 StringRef Identifier, DIE &RefDie,
2267 DICompositeType CTy) {
2268 // Fast path if we're building some type units and one has already used the
2269 // address pool we know we're going to throw away all this work anyway, so
2270 // don't bother building dependent types.
2271 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2274 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2276 CU.addDIETypeSignature(RefDie, *TU);
2280 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2281 AddrPool.resetUsedFlag();
2283 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2284 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2285 this, &InfoHolder, getDwoLineTable(CU));
2286 DwarfTypeUnit &NewTU = *OwnedUnit;
2287 DIE &UnitDie = NewTU.getUnitDie();
2289 TypeUnitsUnderConstruction.push_back(
2290 std::make_pair(std::move(OwnedUnit), CTy));
2292 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2295 uint64_t Signature = makeTypeSignature(Identifier);
2296 NewTU.setTypeSignature(Signature);
2298 if (useSplitDwarf())
2299 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2300 DwarfTypesDWOSectionSym);
2302 CU.applyStmtList(UnitDie);
2304 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2307 NewTU.setType(NewTU.createTypeDIE(CTy));
2310 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2311 TypeUnitsUnderConstruction.clear();
2313 // Types referencing entries in the address table cannot be placed in type
2315 if (AddrPool.hasBeenUsed()) {
2317 // Remove all the types built while building this type.
2318 // This is pessimistic as some of these types might not be dependent on
2319 // the type that used an address.
2320 for (const auto &TU : TypeUnitsToAdd)
2321 DwarfTypeUnits.erase(TU.second);
2323 // Construct this type in the CU directly.
2324 // This is inefficient because all the dependent types will be rebuilt
2325 // from scratch, including building them in type units, discovering that
2326 // they depend on addresses, throwing them out and rebuilding them.
2327 CU.constructTypeDIE(RefDie, CTy);
2331 // If the type wasn't dependent on fission addresses, finish adding the type
2332 // and all its dependent types.
2333 for (auto &TU : TypeUnitsToAdd)
2334 InfoHolder.addUnit(std::move(TU.first));
2336 CU.addDIETypeSignature(RefDie, NewTU);
2339 // Accelerator table mutators - add each name along with its companion
2340 // DIE to the proper table while ensuring that the name that we're going
2341 // to reference is in the string table. We do this since the names we
2342 // add may not only be identical to the names in the DIE.
2343 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2344 if (!useDwarfAccelTables())
2346 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2350 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2351 if (!useDwarfAccelTables())
2353 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2357 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2358 if (!useDwarfAccelTables())
2360 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2364 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2365 if (!useDwarfAccelTables())
2367 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),