1 //===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains support for writing dwarf debug info into asm files.
11 //
12 //===----------------------------------------------------------------------===//
14 #include "ByteStreamer.h"
15 #include "DwarfDebug.h"
16 #include "DIE.h"
17 #include "DIEHash.h"
18 #include "DwarfUnit.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/ADT/StringExtras.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineModuleInfo.h"
25 #include "llvm/IR/Constants.h"
26 #include "llvm/IR/DIBuilder.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DebugInfo.h"
29 #include "llvm/IR/Instructions.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/IR/ValueHandle.h"
32 #include "llvm/MC/MCAsmInfo.h"
33 #include "llvm/MC/MCSection.h"
34 #include "llvm/MC/MCStreamer.h"
35 #include "llvm/MC/MCSymbol.h"
36 #include "llvm/Support/CommandLine.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/Dwarf.h"
39 #include "llvm/Support/ErrorHandling.h"
40 #include "llvm/Support/FormattedStream.h"
41 #include "llvm/Support/LEB128.h"
42 #include "llvm/Support/MD5.h"
43 #include "llvm/Support/Path.h"
44 #include "llvm/Support/Timer.h"
45 #include "llvm/Target/TargetFrameLowering.h"
46 #include "llvm/Target/TargetLoweringObjectFile.h"
47 #include "llvm/Target/TargetMachine.h"
48 #include "llvm/Target/TargetOptions.h"
49 #include "llvm/Target/TargetRegisterInfo.h"
50 using namespace llvm;
52 #define DEBUG_TYPE "dwarfdebug"
54 static cl::opt<bool>
55 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
56 cl::desc("Disable debug info printing"));
58 static cl::opt<bool> UnknownLocations(
59 "use-unknown-locations", cl::Hidden,
60 cl::desc("Make an absence of debug location information explicit."),
61 cl::init(false));
63 static cl::opt<bool>
64 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
65 cl::desc("Generate GNU-style pubnames and pubtypes"),
66 cl::init(false));
68 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
69 cl::Hidden,
70 cl::desc("Generate dwarf aranges"),
71 cl::init(false));
73 namespace {
74 enum DefaultOnOff { Default, Enable, Disable };
75 }
77 static cl::opt<DefaultOnOff>
78 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
79 cl::desc("Output prototype dwarf accelerator tables."),
80 cl::values(clEnumVal(Default, "Default for platform"),
81 clEnumVal(Enable, "Enabled"),
82 clEnumVal(Disable, "Disabled"), clEnumValEnd),
83 cl::init(Default));
85 static cl::opt<DefaultOnOff>
86 SplitDwarf("split-dwarf", cl::Hidden,
87 cl::desc("Output DWARF5 split debug info."),
88 cl::values(clEnumVal(Default, "Default for platform"),
89 clEnumVal(Enable, "Enabled"),
90 clEnumVal(Disable, "Disabled"), clEnumValEnd),
91 cl::init(Default));
93 static cl::opt<DefaultOnOff>
94 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
95 cl::desc("Generate DWARF pubnames and pubtypes sections"),
96 cl::values(clEnumVal(Default, "Default for platform"),
97 clEnumVal(Enable, "Enabled"),
98 clEnumVal(Disable, "Disabled"), clEnumValEnd),
99 cl::init(Default));
101 static cl::opt<unsigned>
102 DwarfVersionNumber("dwarf-version", cl::Hidden,
103 cl::desc("Generate DWARF for dwarf version."), cl::init(0));
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);
114 }
116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
119 }
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. */
150 DIType subType = Ty;
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).getTypeArray();
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()));
161 }
162 }
163 return Ty;
164 }
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 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
177 dwarf::DW_FORM_data4)),
178 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
179 dwarf::DW_FORM_data4)),
180 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
181 dwarf::DW_FORM_data4)),
182 AccelTypes(TypeAtoms) {
184 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
185 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
186 DwarfLineSectionSym = nullptr;
187 DwarfAddrSectionSym = nullptr;
188 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
189 FunctionBeginSym = FunctionEndSym = nullptr;
190 CurFn = nullptr;
191 CurMI = nullptr;
193 // Turn on accelerator tables for Darwin by default, pubnames by
194 // default for non-Darwin, and handle split dwarf.
195 bool IsDarwin = Triple(A->getTargetTriple()).isOSDarwin();
197 if (DwarfAccelTables == Default)
198 HasDwarfAccelTables = IsDarwin;
199 else
200 HasDwarfAccelTables = DwarfAccelTables == Enable;
202 if (SplitDwarf == Default)
203 HasSplitDwarf = false;
204 else
205 HasSplitDwarf = SplitDwarf == Enable;
207 if (DwarfPubSections == Default)
208 HasDwarfPubSections = !IsDarwin;
209 else
210 HasDwarfPubSections = DwarfPubSections == Enable;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
215 {
216 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
217 beginModule();
218 }
219 }
221 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
222 DwarfDebug::~DwarfDebug() { }
224 // Switch to the specified MCSection and emit an assembler
225 // temporary label to it if SymbolStem is specified.
226 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
227 const char *SymbolStem = nullptr) {
228 Asm->OutStreamer.SwitchSection(Section);
229 if (!SymbolStem)
230 return nullptr;
232 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
233 Asm->OutStreamer.EmitLabel(TmpSym);
234 return TmpSym;
235 }
237 static bool isObjCClass(StringRef Name) {
238 return Name.startswith("+") || Name.startswith("-");
239 }
241 static bool hasObjCCategory(StringRef Name) {
242 if (!isObjCClass(Name))
243 return false;
245 return Name.find(") ") != StringRef::npos;
246 }
248 static void getObjCClassCategory(StringRef In, StringRef &Class,
249 StringRef &Category) {
250 if (!hasObjCCategory(In)) {
251 Class = In.slice(In.find('[') + 1, In.find(' '));
252 Category = "";
253 return;
254 }
256 Class = In.slice(In.find('[') + 1, In.find('('));
257 Category = In.slice(In.find('[') + 1, In.find(' '));
258 return;
259 }
261 static StringRef getObjCMethodName(StringRef In) {
262 return In.slice(In.find(' ') + 1, In.find(']'));
263 }
265 // Helper for sorting sections into a stable output order.
266 static bool SectionSort(const MCSection *A, const MCSection *B) {
267 std::string LA = (A ? A->getLabelBeginName() : "");
268 std::string LB = (B ? B->getLabelBeginName() : "");
269 return LA < LB;
270 }
272 // Add the various names to the Dwarf accelerator table names.
273 // TODO: Determine whether or not we should add names for programs
274 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
275 // is only slightly different than the lookup of non-standard ObjC names.
276 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
277 if (!SP.isDefinition())
278 return;
279 addAccelName(SP.getName(), Die);
281 // If the linkage name is different than the name, go ahead and output
282 // that as well into the name table.
283 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
284 addAccelName(SP.getLinkageName(), Die);
286 // If this is an Objective-C selector name add it to the ObjC accelerator
287 // too.
288 if (isObjCClass(SP.getName())) {
289 StringRef Class, Category;
290 getObjCClassCategory(SP.getName(), Class, Category);
291 addAccelObjC(Class, Die);
292 if (Category != "")
293 addAccelObjC(Category, Die);
294 // Also add the base method name to the name table.
295 addAccelName(getObjCMethodName(SP.getName()), Die);
296 }
297 }
299 /// isSubprogramContext - Return true if Context is either a subprogram
300 /// or another context nested inside a subprogram.
301 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
302 if (!Context)
303 return false;
304 DIDescriptor D(Context);
305 if (D.isSubprogram())
306 return true;
307 if (D.isType())
308 return isSubprogramContext(resolve(DIType(Context).getContext()));
309 return false;
310 }
312 // Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
313 // and DW_AT_high_pc attributes. If there are global variables in this
314 // scope then create and insert DIEs for these variables.
315 DIE &DwarfDebug::updateSubprogramScopeDIE(DwarfCompileUnit &SPCU,
316 DISubprogram SP) {
317 DIE *SPDie = SPCU.getDIE(SP);
319 assert(SPDie && "Unable to find subprogram DIE!");
321 // If we're updating an abstract DIE, then we will be adding the children and
322 // object pointer later on. But what we don't want to do is process the
323 // concrete DIE twice.
324 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
325 // Pick up abstract subprogram DIE.
326 SPDie = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, SPCU.getUnitDie());
327 SPCU.addDIEEntry(*SPDie, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
328 } else {
329 DISubprogram SPDecl = SP.getFunctionDeclaration();
330 if (!SPDecl.isSubprogram()) {
331 // There is not any need to generate specification DIE for a function
332 // defined at compile unit level. If a function is defined inside another
333 // function then gdb prefers the definition at top level and but does not
334 // expect specification DIE in parent function. So avoid creating
335 // specification DIE for a function defined inside a function.
336 DIScope SPContext = resolve(SP.getContext());
337 if (SP.isDefinition() && !SPContext.isCompileUnit() &&
338 !SPContext.isFile() && !isSubprogramContext(SPContext)) {
339 SPCU.addFlag(*SPDie, dwarf::DW_AT_declaration);
341 // Add arguments.
342 DICompositeType SPTy = SP.getType();
343 DIArray Args = SPTy.getTypeArray();
344 uint16_t SPTag = SPTy.getTag();
345 if (SPTag == dwarf::DW_TAG_subroutine_type)
346 SPCU.constructSubprogramArguments(*SPDie, Args);
347 DIE *SPDeclDie = SPDie;
348 SPDie =
349 &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, SPCU.getUnitDie());
350 SPCU.addDIEEntry(*SPDie, dwarf::DW_AT_specification, *SPDeclDie);
351 }
352 }
353 }
355 attachLowHighPC(SPCU, *SPDie, FunctionBeginSym, FunctionEndSym);
357 const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
358 MachineLocation Location(RI->getFrameRegister(*Asm->MF));
359 SPCU.addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
361 // Add name to the name table, we do this here because we're guaranteed
362 // to have concrete versions of our DW_TAG_subprogram nodes.
363 addSubprogramNames(SP, *SPDie);
365 return *SPDie;
366 }
368 /// Check whether we should create a DIE for the given Scope, return true
369 /// if we don't create a DIE (the corresponding DIE is null).
370 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
371 if (Scope->isAbstractScope())
372 return false;
374 // We don't create a DIE if there is no Range.
375 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
376 if (Ranges.empty())
377 return true;
379 if (Ranges.size() > 1)
380 return false;
382 // We don't create a DIE if we have a single Range and the end label
383 // is null.
384 SmallVectorImpl<InsnRange>::const_iterator RI = Ranges.begin();
385 MCSymbol *End = getLabelAfterInsn(RI->second);
386 return !End;
387 }
389 static void addSectionLabel(AsmPrinter &Asm, DwarfUnit &U, DIE &D,
390 dwarf::Attribute A, const MCSymbol *L,
391 const MCSymbol *Sec) {
392 if (Asm.MAI->doesDwarfUseRelocationsAcrossSections())
393 U.addSectionLabel(D, A, L);
394 else
395 U.addSectionDelta(D, A, L, Sec);
396 }
398 void DwarfDebug::addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
399 const SmallVectorImpl<InsnRange> &Range) {
400 // Emit offset in .debug_range as a relocatable label. emitDIE will handle
401 // emitting it appropriately.
402 MCSymbol *RangeSym = Asm->GetTempSymbol("debug_ranges", GlobalRangeCount++);
404 // Under fission, ranges are specified by constant offsets relative to the
405 // CU's DW_AT_GNU_ranges_base.
406 if (useSplitDwarf())
407 TheCU.addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
408 DwarfDebugRangeSectionSym);
409 else
410 addSectionLabel(*Asm, TheCU, ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
411 DwarfDebugRangeSectionSym);
413 RangeSpanList List(RangeSym);
414 for (const InsnRange &R : Range) {
415 RangeSpan Span(getLabelBeforeInsn(R.first), getLabelAfterInsn(R.second));
416 List.addRange(std::move(Span));
417 }
419 // Add the range list to the set of ranges to be emitted.
420 TheCU.addRangeList(std::move(List));
421 }
423 // Construct new DW_TAG_lexical_block for this scope and attach
424 // DW_AT_low_pc/DW_AT_high_pc labels.
425 std::unique_ptr<DIE>
426 DwarfDebug::constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
427 LexicalScope *Scope) {
428 if (isLexicalScopeDIENull(Scope))
429 return nullptr;
431 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
432 if (Scope->isAbstractScope())
433 return ScopeDIE;
435 const SmallVectorImpl<InsnRange> &ScopeRanges = Scope->getRanges();
437 // If we have multiple ranges, emit them into the range section.
438 if (ScopeRanges.size() > 1) {
439 addScopeRangeList(TheCU, *ScopeDIE, ScopeRanges);
440 return ScopeDIE;
441 }
443 // Construct the address range for this DIE.
444 SmallVectorImpl<InsnRange>::const_iterator RI = ScopeRanges.begin();
445 MCSymbol *Start = getLabelBeforeInsn(RI->first);
446 MCSymbol *End = getLabelAfterInsn(RI->second);
447 assert(End && "End label should not be null!");
449 assert(Start->isDefined() && "Invalid starting label for an inlined scope!");
450 assert(End->isDefined() && "Invalid end label for an inlined scope!");
452 attachLowHighPC(TheCU, *ScopeDIE, Start, End);
454 return ScopeDIE;
455 }
457 // This scope represents inlined body of a function. Construct DIE to
458 // represent this concrete inlined copy of the function.
459 std::unique_ptr<DIE>
460 DwarfDebug::constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
461 LexicalScope *Scope) {
462 const SmallVectorImpl<InsnRange> &ScopeRanges = Scope->getRanges();
463 assert(!ScopeRanges.empty() &&
464 "LexicalScope does not have instruction markers!");
466 if (!Scope->getScopeNode())
467 return nullptr;
468 DIScope DS(Scope->getScopeNode());
469 DISubprogram InlinedSP = getDISubprogram(DS);
470 DIE *OriginDIE = TheCU.getDIE(InlinedSP);
471 if (!OriginDIE) {
472 DEBUG(dbgs() << "Unable to find original DIE for an inlined subprogram.");
473 return nullptr;
474 }
476 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
477 TheCU.addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
479 // If we have multiple ranges, emit them into the range section.
480 if (ScopeRanges.size() > 1)
481 addScopeRangeList(TheCU, *ScopeDIE, ScopeRanges);
482 else {
483 SmallVectorImpl<InsnRange>::const_iterator RI = ScopeRanges.begin();
484 MCSymbol *StartLabel = getLabelBeforeInsn(RI->first);
485 MCSymbol *EndLabel = getLabelAfterInsn(RI->second);
487 if (!StartLabel || !EndLabel)
488 llvm_unreachable("Unexpected Start and End labels for an inlined scope!");
490 assert(StartLabel->isDefined() &&
491 "Invalid starting label for an inlined scope!");
492 assert(EndLabel->isDefined() && "Invalid end label for an inlined scope!");
494 attachLowHighPC(TheCU, *ScopeDIE, StartLabel, EndLabel);
495 }
497 InlinedSubprogramDIEs.insert(OriginDIE);
499 // Add the call site information to the DIE.
500 DILocation DL(Scope->getInlinedAt());
501 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
502 TheCU.getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
503 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
505 // Add name to the name table, we do this here because we're guaranteed
506 // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
507 addSubprogramNames(InlinedSP, *ScopeDIE);
509 return ScopeDIE;
510 }
512 DIE *DwarfDebug::createScopeChildrenDIE(
513 DwarfCompileUnit &TheCU, LexicalScope *Scope,
514 SmallVectorImpl<std::unique_ptr<DIE>> &Children) {
515 DIE *ObjectPointer = nullptr;
517 // Collect arguments for current function.
518 if (LScopes.isCurrentFunctionScope(Scope)) {
519 for (DbgVariable *ArgDV : CurrentFnArguments)
520 if (ArgDV) {
521 Children.push_back(
522 TheCU.constructVariableDIE(*ArgDV, Scope->isAbstractScope()));
523 if (ArgDV->isObjectPointer())
524 ObjectPointer = Children.back().get();
525 }
527 // If this is a variadic function, add an unspecified parameter.
528 DISubprogram SP(Scope->getScopeNode());
529 DIArray FnArgs = SP.getType().getTypeArray();
530 if (FnArgs.getElement(FnArgs.getNumElements() - 1)
531 .isUnspecifiedParameter()) {
532 Children.push_back(
533 make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
534 }
535 }
537 // Collect lexical scope children first.
538 for (DbgVariable *DV : ScopeVariables.lookup(Scope)) {
539 Children.push_back(
540 TheCU.constructVariableDIE(*DV, Scope->isAbstractScope()));
541 if (DV->isObjectPointer())
542 ObjectPointer = Children.back().get();
543 }
544 for (LexicalScope *LS : Scope->getChildren())
545 if (std::unique_ptr<DIE> Nested = constructScopeDIE(TheCU, LS))
546 Children.push_back(std::move(Nested));
547 return ObjectPointer;
548 }
550 void DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU,
551 LexicalScope *Scope,
552 DISubprogram Sub, DIE &ScopeDIE) {
553 // We create children when the scope DIE is not null.
554 SmallVector<std::unique_ptr<DIE>, 8> Children;
555 if (DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children))
556 // The declaration will have the object_pointer, otherwise put it on the
557 // definition. This happens with ObjC blocks that have object_pointer on
558 // non-member functions.
559 if (!Sub.getFunctionDeclaration())
560 TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
562 // Add children
563 for (auto &I : Children)
564 ScopeDIE.addChild(std::move(I));
565 }
567 void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
568 LexicalScope *Scope) {
569 assert(Scope && Scope->getScopeNode());
570 assert(Scope->isAbstractScope());
571 assert(!Scope->getInlinedAt());
573 DISubprogram Sub(Scope->getScopeNode());
575 ProcessedSPNodes.insert(Sub);
577 if (DIE *ScopeDIE = TheCU.getDIE(Sub)) {
578 AbstractSPDies.insert(std::make_pair(Sub, ScopeDIE));
579 createAndAddScopeChildren(TheCU, Scope, Sub, *ScopeDIE);
580 }
581 }
583 DIE &DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
584 LexicalScope *Scope) {
585 assert(Scope && Scope->getScopeNode());
586 assert(!Scope->getInlinedAt());
587 assert(!Scope->isAbstractScope());
588 assert(DIScope(Scope->getScopeNode()).isSubprogram());
590 DISubprogram Sub(Scope->getScopeNode());
592 ProcessedSPNodes.insert(Sub);
594 DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub);
596 createAndAddScopeChildren(TheCU, Scope, Sub, ScopeDIE);
598 return ScopeDIE;
599 }
601 // Construct a DIE for this scope.
602 std::unique_ptr<DIE> DwarfDebug::constructScopeDIE(DwarfCompileUnit &TheCU,
603 LexicalScope *Scope) {
604 if (!Scope || !Scope->getScopeNode())
605 return nullptr;
607 DIScope DS(Scope->getScopeNode());
609 assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
610 "Only handle inlined subprograms here, use "
611 "constructSubprogramScopeDIE for non-inlined "
612 "subprograms");
614 SmallVector<std::unique_ptr<DIE>, 8> Children;
616 // We try to create the scope DIE first, then the children DIEs. This will
617 // avoid creating un-used children then removing them later when we find out
618 // the scope DIE is null.
619 std::unique_ptr<DIE> ScopeDIE;
620 if (Scope->getInlinedAt()) {
621 ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
622 if (!ScopeDIE)
623 return nullptr;
624 // We create children when the scope DIE is not null.
625 createScopeChildrenDIE(TheCU, Scope, Children);
626 } else {
627 // Early exit when we know the scope DIE is going to be null.
628 if (isLexicalScopeDIENull(Scope))
629 return nullptr;
631 // We create children here when we know the scope DIE is not going to be
632 // null and the children will be added to the scope DIE.
633 createScopeChildrenDIE(TheCU, Scope, Children);
635 // There is no need to emit empty lexical block DIE.
636 std::pair<ImportedEntityMap::const_iterator,
637 ImportedEntityMap::const_iterator> Range =
638 std::equal_range(ScopesWithImportedEntities.begin(),
639 ScopesWithImportedEntities.end(),
640 std::pair<const MDNode *, const MDNode *>(DS, nullptr),
641 less_first());
642 if (Children.empty() && Range.first == Range.second)
643 return nullptr;
644 ScopeDIE = constructLexicalScopeDIE(TheCU, Scope);
645 assert(ScopeDIE && "Scope DIE should not be null.");
646 for (ImportedEntityMap::const_iterator i = Range.first; i != Range.second;
647 ++i)
648 constructImportedEntityDIE(TheCU, i->second, *ScopeDIE);
649 }
651 // Add children
652 for (auto &I : Children)
653 ScopeDIE->addChild(std::move(I));
655 return ScopeDIE;
656 }
658 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
659 if (!GenerateGnuPubSections)
660 return;
662 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
663 }
665 // Create new DwarfCompileUnit for the given metadata node with tag
666 // DW_TAG_compile_unit.
667 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
668 StringRef FN = DIUnit.getFilename();
669 CompilationDir = DIUnit.getDirectory();
671 auto OwnedUnit = make_unique<DwarfCompileUnit>(
672 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
673 DwarfCompileUnit &NewCU = *OwnedUnit;
674 DIE &Die = NewCU.getUnitDie();
675 InfoHolder.addUnit(std::move(OwnedUnit));
677 // LTO with assembly output shares a single line table amongst multiple CUs.
678 // To avoid the compilation directory being ambiguous, let the line table
679 // explicitly describe the directory of all files, never relying on the
680 // compilation directory.
681 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
682 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
683 NewCU.getUniqueID(), CompilationDir);
685 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
686 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
687 DIUnit.getLanguage());
688 NewCU.addString(Die, dwarf::DW_AT_name, FN);
690 if (!useSplitDwarf()) {
691 NewCU.initStmtList(DwarfLineSectionSym);
693 // If we're using split dwarf the compilation dir is going to be in the
694 // skeleton CU and so we don't need to duplicate it here.
695 if (!CompilationDir.empty())
696 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
698 addGnuPubAttributes(NewCU, Die);
699 }
701 if (DIUnit.isOptimized())
702 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
704 StringRef Flags = DIUnit.getFlags();
705 if (!Flags.empty())
706 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
708 if (unsigned RVer = DIUnit.getRunTimeVersion())
709 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
710 dwarf::DW_FORM_data1, RVer);
712 if (!FirstCU)
713 FirstCU = &NewCU;
715 if (useSplitDwarf()) {
716 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
717 DwarfInfoDWOSectionSym);
718 NewCU.setSkeleton(constructSkeletonCU(NewCU));
719 } else
720 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
721 DwarfInfoSectionSym);
723 CUMap.insert(std::make_pair(DIUnit, &NewCU));
724 CUDieMap.insert(std::make_pair(&Die, &NewCU));
725 return NewCU;
726 }
728 // Construct subprogram DIE.
729 void DwarfDebug::constructSubprogramDIE(DwarfCompileUnit &TheCU,
730 const MDNode *N) {
731 // FIXME: We should only call this routine once, however, during LTO if a
732 // program is defined in multiple CUs we could end up calling it out of
733 // beginModule as we walk the CUs.
735 DwarfCompileUnit *&CURef = SPMap[N];
736 if (CURef)
737 return;
738 CURef = &TheCU;
740 DISubprogram SP(N);
741 if (!SP.isDefinition())
742 // This is a method declaration which will be handled while constructing
743 // class type.
744 return;
746 DIE &SubprogramDie = *TheCU.getOrCreateSubprogramDIE(SP);
748 // Expose as a global name.
749 TheCU.addGlobalName(SP.getName(), SubprogramDie, resolve(SP.getContext()));
750 }
752 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
753 const MDNode *N) {
754 DIImportedEntity Module(N);
755 assert(Module.Verify());
756 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
757 constructImportedEntityDIE(TheCU, Module, *D);
758 }
760 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
761 const MDNode *N, DIE &Context) {
762 DIImportedEntity Module(N);
763 assert(Module.Verify());
764 return constructImportedEntityDIE(TheCU, Module, Context);
765 }
767 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
768 const DIImportedEntity &Module,
769 DIE &Context) {
770 assert(Module.Verify() &&
771 "Use one of the MDNode * overloads to handle invalid metadata");
772 DIE &IMDie = TheCU.createAndAddDIE(Module.getTag(), Context, Module);
773 DIE *EntityDie;
774 DIDescriptor Entity = resolve(Module.getEntity());
775 if (Entity.isNameSpace())
776 EntityDie = TheCU.getOrCreateNameSpace(DINameSpace(Entity));
777 else if (Entity.isSubprogram())
778 EntityDie = TheCU.getOrCreateSubprogramDIE(DISubprogram(Entity));
779 else if (Entity.isType())
780 EntityDie = TheCU.getOrCreateTypeDIE(DIType(Entity));
781 else
782 EntityDie = TheCU.getDIE(Entity);
783 TheCU.addSourceLine(IMDie, Module.getLineNumber(),
784 Module.getContext().getFilename(),
785 Module.getContext().getDirectory());
786 TheCU.addDIEEntry(IMDie, dwarf::DW_AT_import, *EntityDie);
787 StringRef Name = Module.getName();
788 if (!Name.empty())
789 TheCU.addString(IMDie, dwarf::DW_AT_name, Name);
790 }
792 // Emit all Dwarf sections that should come prior to the content. Create
793 // global DIEs and emit initial debug info sections. This is invoked by
794 // the target AsmPrinter.
795 void DwarfDebug::beginModule() {
796 if (DisableDebugInfoPrinting)
797 return;
799 const Module *M = MMI->getModule();
801 // If module has named metadata anchors then use them, otherwise scan the
802 // module using debug info finder to collect debug info.
803 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
804 if (!CU_Nodes)
805 return;
806 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
808 // Emit initial sections so we can reference labels later.
809 emitSectionLabels();
811 SingleCU = CU_Nodes->getNumOperands() == 1;
813 for (MDNode *N : CU_Nodes->operands()) {
814 DICompileUnit CUNode(N);
815 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
816 DIArray ImportedEntities = CUNode.getImportedEntities();
817 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
818 ScopesWithImportedEntities.push_back(std::make_pair(
819 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
820 ImportedEntities.getElement(i)));
821 std::sort(ScopesWithImportedEntities.begin(),
822 ScopesWithImportedEntities.end(), less_first());
823 DIArray GVs = CUNode.getGlobalVariables();
824 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
825 CU.createGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
826 DIArray SPs = CUNode.getSubprograms();
827 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
828 constructSubprogramDIE(CU, SPs.getElement(i));
829 DIArray EnumTypes = CUNode.getEnumTypes();
830 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
831 CU.getOrCreateTypeDIE(EnumTypes.getElement(i));
832 DIArray RetainedTypes = CUNode.getRetainedTypes();
833 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
834 DIType Ty(RetainedTypes.getElement(i));
835 // The retained types array by design contains pointers to
836 // MDNodes rather than DIRefs. Unique them here.
837 DIType UniqueTy(resolve(Ty.getRef()));
838 CU.getOrCreateTypeDIE(UniqueTy);
839 }
840 // Emit imported_modules last so that the relevant context is already
841 // available.
842 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
843 constructImportedEntityDIE(CU, ImportedEntities.getElement(i));
844 }
846 // Tell MMI that we have debug info.
847 MMI->setDebugInfoAvailability(true);
849 // Prime section data.
850 SectionMap[Asm->getObjFileLowering().getTextSection()];
851 }
853 // Attach DW_AT_inline attribute with inlined subprogram DIEs.
854 void DwarfDebug::computeInlinedDIEs() {
855 // Attach DW_AT_inline attribute with inlined subprogram DIEs.
856 for (DIE *ISP : InlinedSubprogramDIEs)
857 FirstCU->addUInt(*ISP, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
859 for (const auto &AI : AbstractSPDies) {
860 DIE &ISP = *AI.second;
861 if (InlinedSubprogramDIEs.count(&ISP))
862 continue;
863 FirstCU->addUInt(ISP, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
864 }
865 }
867 // Collect info for variables that were optimized out.
868 void DwarfDebug::collectDeadVariables() {
869 const Module *M = MMI->getModule();
871 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
872 for (MDNode *N : CU_Nodes->operands()) {
873 DICompileUnit TheCU(N);
874 DIArray Subprograms = TheCU.getSubprograms();
875 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
876 DISubprogram SP(Subprograms.getElement(i));
877 if (ProcessedSPNodes.count(SP) != 0)
878 continue;
879 if (!SP.isSubprogram())
880 continue;
881 if (!SP.isDefinition())
882 continue;
883 DIArray Variables = SP.getVariables();
884 if (Variables.getNumElements() == 0)
885 continue;
887 // Construct subprogram DIE and add variables DIEs.
888 DwarfCompileUnit *SPCU =
889 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
890 assert(SPCU && "Unable to find Compile Unit!");
891 // FIXME: See the comment in constructSubprogramDIE about duplicate
892 // subprogram DIEs.
893 constructSubprogramDIE(*SPCU, SP);
894 DIE *SPDIE = SPCU->getDIE(SP);
895 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
896 DIVariable DV(Variables.getElement(vi));
897 if (!DV.isVariable())
898 continue;
899 DbgVariable NewVar(DV, nullptr, this);
900 SPDIE->addChild(SPCU->constructVariableDIE(NewVar, false));
901 }
902 }
903 }
904 }
905 }
907 void DwarfDebug::finalizeModuleInfo() {
908 // Collect info for variables that were optimized out.
909 collectDeadVariables();
911 // Attach DW_AT_inline attribute with inlined subprogram DIEs.
912 computeInlinedDIEs();
914 // Handle anything that needs to be done on a per-unit basis after
915 // all other generation.
916 for (const auto &TheU : getUnits()) {
917 // Emit DW_AT_containing_type attribute to connect types with their
918 // vtable holding type.
919 TheU->constructContainingTypeDIEs();
921 // Add CU specific attributes if we need to add any.
922 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
923 // If we're splitting the dwarf out now that we've got the entire
924 // CU then add the dwo id to it.
925 DwarfCompileUnit *SkCU =
926 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
927 if (useSplitDwarf()) {
928 // Emit a unique identifier for this CU.
929 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
930 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
931 dwarf::DW_FORM_data8, ID);
932 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
933 dwarf::DW_FORM_data8, ID);
935 // We don't keep track of which addresses are used in which CU so this
936 // is a bit pessimistic under LTO.
937 if (!AddrPool.isEmpty())
938 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
939 dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
940 DwarfAddrSectionSym);
941 if (!TheU->getRangeLists().empty())
942 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
943 dwarf::DW_AT_GNU_ranges_base,
944 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
945 }
947 // If we have code split among multiple sections or non-contiguous
948 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
949 // remain in the .o file, otherwise add a DW_AT_low_pc.
950 // FIXME: We should use ranges allow reordering of code ala
951 // .subsections_via_symbols in mach-o. This would mean turning on
952 // ranges for all subprogram DIEs for mach-o.
953 DwarfCompileUnit &U =
954 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
955 unsigned NumRanges = TheU->getRanges().size();
956 if (NumRanges) {
957 if (NumRanges > 1) {
958 addSectionLabel(*Asm, U, U.getUnitDie(), dwarf::DW_AT_ranges,
959 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
960 DwarfDebugRangeSectionSym);
962 // A DW_AT_low_pc attribute may also be specified in combination with
963 // DW_AT_ranges to specify the default base address for use in
964 // location lists (see Section 2.6.2) and range lists (see Section
965 // 2.17.3).
966 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
967 0);
968 } else {
969 RangeSpan &Range = TheU->getRanges().back();
970 U.addLocalLabelAddress(U.getUnitDie(), dwarf::DW_AT_low_pc,
971 Range.getStart());
972 U.addLabelDelta(U.getUnitDie(), dwarf::DW_AT_high_pc, Range.getEnd(),
973 Range.getStart());
974 }
975 }
976 }
977 }
979 // Compute DIE offsets and sizes.
980 InfoHolder.computeSizeAndOffsets();
981 if (useSplitDwarf())
982 SkeletonHolder.computeSizeAndOffsets();
983 }
985 void DwarfDebug::endSections() {
986 // Filter labels by section.
987 for (const SymbolCU &SCU : ArangeLabels) {
988 if (SCU.Sym->isInSection()) {
989 // Make a note of this symbol and it's section.
990 const MCSection *Section = &SCU.Sym->getSection();
991 if (!Section->getKind().isMetadata())
992 SectionMap[Section].push_back(SCU);
993 } else {
994 // Some symbols (e.g. common/bss on mach-o) can have no section but still
995 // appear in the output. This sucks as we rely on sections to build
996 // arange spans. We can do it without, but it's icky.
997 SectionMap[nullptr].push_back(SCU);
998 }
999 }
1001 // Build a list of sections used.
1002 std::vector<const MCSection *> Sections;
1003 for (const auto &it : SectionMap) {
1004 const MCSection *Section = it.first;
1005 Sections.push_back(Section);
1006 }
1008 // Sort the sections into order.
1009 // This is only done to ensure consistent output order across different runs.
1010 std::sort(Sections.begin(), Sections.end(), SectionSort);
1012 // Add terminating symbols for each section.
1013 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
1014 const MCSection *Section = Sections[ID];
1015 MCSymbol *Sym = nullptr;
1017 if (Section) {
1018 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1019 // if we know the section name up-front. For user-created sections, the
1020 // resulting label may not be valid to use as a label. (section names can
1021 // use a greater set of characters on some systems)
1022 Sym = Asm->GetTempSymbol("debug_end", ID);
1023 Asm->OutStreamer.SwitchSection(Section);
1024 Asm->OutStreamer.EmitLabel(Sym);
1025 }
1027 // Insert a final terminator.
1028 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1029 }
1030 }
1032 // Emit all Dwarf sections that should come after the content.
1033 void DwarfDebug::endModule() {
1034 assert(CurFn == nullptr);
1035 assert(CurMI == nullptr);
1037 if (!FirstCU)
1038 return;
1040 // End any existing sections.
1041 // TODO: Does this need to happen?
1042 endSections();
1044 // Finalize the debug info for the module.
1045 finalizeModuleInfo();
1047 emitDebugStr();
1049 // Emit all the DIEs into a debug info section.
1050 emitDebugInfo();
1052 // Corresponding abbreviations into a abbrev section.
1053 emitAbbreviations();
1055 // Emit info into a debug aranges section.
1056 if (GenerateARangeSection)
1057 emitDebugARanges();
1059 // Emit info into a debug ranges section.
1060 emitDebugRanges();
1062 if (useSplitDwarf()) {
1063 emitDebugStrDWO();
1064 emitDebugInfoDWO();
1065 emitDebugAbbrevDWO();
1066 emitDebugLineDWO();
1067 // Emit DWO addresses.
1068 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
1069 emitDebugLocDWO();
1070 } else
1071 // Emit info into a debug loc section.
1072 emitDebugLoc();
1074 // Emit info into the dwarf accelerator table sections.
1075 if (useDwarfAccelTables()) {
1076 emitAccelNames();
1077 emitAccelObjC();
1078 emitAccelNamespaces();
1079 emitAccelTypes();
1080 }
1082 // Emit the pubnames and pubtypes sections if requested.
1083 if (HasDwarfPubSections) {
1084 emitDebugPubNames(GenerateGnuPubSections);
1085 emitDebugPubTypes(GenerateGnuPubSections);
1086 }
1088 // clean up.
1089 SPMap.clear();
1091 // Reset these for the next Module if we have one.
1092 FirstCU = nullptr;
1093 }
1095 // Find abstract variable, if any, associated with Var.
1096 DbgVariable *DwarfDebug::findAbstractVariable(DIVariable &DV,
1097 DebugLoc ScopeLoc) {
1098 LLVMContext &Ctx = DV->getContext();
1099 // More then one inlined variable corresponds to one abstract variable.
1100 DIVariable Var = cleanseInlinedVariable(DV, Ctx);
1101 DbgVariable *AbsDbgVariable = AbstractVariables.lookup(Var);
1102 if (AbsDbgVariable)
1103 return AbsDbgVariable;
1105 LexicalScope *Scope = LScopes.findAbstractScope(ScopeLoc.getScope(Ctx));
1106 if (!Scope)
1107 return nullptr;
1109 AbsDbgVariable = new DbgVariable(Var, nullptr, this);
1110 addScopeVariable(Scope, AbsDbgVariable);
1111 AbstractVariables[Var] = AbsDbgVariable;
1112 return AbsDbgVariable;
1113 }
1115 // If Var is a current function argument then add it to CurrentFnArguments list.
1116 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
1117 if (!LScopes.isCurrentFunctionScope(Scope))
1118 return false;
1119 DIVariable DV = Var->getVariable();
1120 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
1121 return false;
1122 unsigned ArgNo = DV.getArgNumber();
1123 if (ArgNo == 0)
1124 return false;
1126 size_t Size = CurrentFnArguments.size();
1127 if (Size == 0)
1128 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
1129 // llvm::Function argument size is not good indicator of how many
1130 // arguments does the function have at source level.
1131 if (ArgNo > Size)
1132 CurrentFnArguments.resize(ArgNo * 2);
1133 CurrentFnArguments[ArgNo - 1] = Var;
1134 return true;
1135 }
1137 // Collect variable information from side table maintained by MMI.
1138 void DwarfDebug::collectVariableInfoFromMMITable(
1139 SmallPtrSet<const MDNode *, 16> &Processed) {
1140 for (const auto &VI : MMI->getVariableDbgInfo()) {
1141 if (!VI.Var)
1142 continue;
1143 Processed.insert(VI.Var);
1144 DIVariable DV(VI.Var);
1145 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
1147 // If variable scope is not found then skip this variable.
1148 if (!Scope)
1149 continue;
1151 DbgVariable *AbsDbgVariable = findAbstractVariable(DV, VI.Loc);
1152 DbgVariable *RegVar = new DbgVariable(DV, AbsDbgVariable, this);
1153 RegVar->setFrameIndex(VI.Slot);
1154 if (!addCurrentFnArgument(RegVar, Scope))
1155 addScopeVariable(Scope, RegVar);
1156 if (AbsDbgVariable)
1157 AbsDbgVariable->setFrameIndex(VI.Slot);
1158 }
1159 }
1161 // Get .debug_loc entry for the instruction range starting at MI.
1162 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
1163 const MDNode *Var = MI->getDebugVariable();
1165 assert(MI->getNumOperands() == 3);
1166 if (MI->getOperand(0).isReg()) {
1167 MachineLocation MLoc;
1168 // If the second operand is an immediate, this is a
1169 // register-indirect address.
1170 if (!MI->getOperand(1).isImm())
1171 MLoc.set(MI->getOperand(0).getReg());
1172 else
1173 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
1174 return DebugLocEntry::Value(Var, MLoc);
1175 }
1176 if (MI->getOperand(0).isImm())
1177 return DebugLocEntry::Value(Var, MI->getOperand(0).getImm());
1178 if (MI->getOperand(0).isFPImm())
1179 return DebugLocEntry::Value(Var, MI->getOperand(0).getFPImm());
1180 if (MI->getOperand(0).isCImm())
1181 return DebugLocEntry::Value(Var, MI->getOperand(0).getCImm());
1183 llvm_unreachable("Unexpected 3 operand DBG_VALUE instruction!");
1184 }
1186 // Find variables for each lexical scope.
1187 void
1188 DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
1189 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1190 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1192 // Grab the variable info that was squirreled away in the MMI side-table.
1193 collectVariableInfoFromMMITable(Processed);
1195 for (const MDNode *Var : UserVariables) {
1196 if (Processed.count(Var))
1197 continue;
1199 // History contains relevant DBG_VALUE instructions for Var and instructions
1200 // clobbering it.
1201 SmallVectorImpl<const MachineInstr *> &History = DbgValues[Var];
1202 if (History.empty())
1203 continue;
1204 const MachineInstr *MInsn = History.front();
1206 DIVariable DV(Var);
1207 LexicalScope *Scope = nullptr;
1208 if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
1209 DISubprogram(DV.getContext()).describes(CurFn->getFunction()))
1210 Scope = LScopes.getCurrentFunctionScope();
1211 else if (MDNode *IA = DV.getInlinedAt())
1212 Scope = LScopes.findInlinedScope(DebugLoc::getFromDILocation(IA));
1213 else
1214 Scope = LScopes.findLexicalScope(cast<MDNode>(DV->getOperand(1)));
1215 // If variable scope is not found then skip this variable.
1216 if (!Scope)
1217 continue;
1219 Processed.insert(DV);
1220 assert(MInsn->isDebugValue() && "History must begin with debug value");
1221 DbgVariable *AbsVar = findAbstractVariable(DV, MInsn->getDebugLoc());
1222 DbgVariable *RegVar = new DbgVariable(DV, AbsVar, this);
1223 if (!addCurrentFnArgument(RegVar, Scope))
1224 addScopeVariable(Scope, RegVar);
1225 if (AbsVar)
1226 AbsVar->setMInsn(MInsn);
1228 // Simplify ranges that are fully coalesced.
1229 if (History.size() <= 1 ||
1230 (History.size() == 2 && MInsn->isIdenticalTo(History.back()))) {
1231 RegVar->setMInsn(MInsn);
1232 continue;
1233 }
1235 // Handle multiple DBG_VALUE instructions describing one variable.
1236 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1238 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1239 DebugLocList &LocList = DotDebugLocEntries.back();
1240 LocList.Label =
1241 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1242 SmallVector<DebugLocEntry, 4> &DebugLoc = LocList.List;
1243 for (SmallVectorImpl<const MachineInstr *>::const_iterator
1244 HI = History.begin(),
1245 HE = History.end();
1246 HI != HE; ++HI) {
1247 const MachineInstr *Begin = *HI;
1248 assert(Begin->isDebugValue() && "Invalid History entry");
1250 // Check if DBG_VALUE is truncating a range.
1251 if (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
1252 !Begin->getOperand(0).getReg())
1253 continue;
1255 // Compute the range for a register location.
1256 const MCSymbol *FLabel = getLabelBeforeInsn(Begin);
1257 const MCSymbol *SLabel = nullptr;
1259 if (HI + 1 == HE)
1260 // If Begin is the last instruction in History then its value is valid
1261 // until the end of the function.
1262 SLabel = FunctionEndSym;
1263 else {
1264 const MachineInstr *End = HI[1];
1265 DEBUG(dbgs() << "DotDebugLoc Pair:\n"
1266 << "\t" << *Begin << "\t" << *End << "\n");
1267 if (End->isDebugValue())
1268 SLabel = getLabelBeforeInsn(End);
1269 else {
1270 // End is a normal instruction clobbering the range.
1271 SLabel = getLabelAfterInsn(End);
1272 assert(SLabel && "Forgot label after clobber instruction");
1273 ++HI;
1274 }
1275 }
1277 // The value is valid until the next DBG_VALUE or clobber.
1278 DebugLocEntry Loc(FLabel, SLabel, getDebugLocValue(Begin), TheCU);
1279 if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc))
1280 DebugLoc.push_back(std::move(Loc));
1281 }
1282 }
1284 // Collect info for variables that were optimized out.
1285 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1286 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1287 DIVariable DV(Variables.getElement(i));
1288 if (!DV || !DV.isVariable() || !Processed.insert(DV))
1289 continue;
1290 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext()))
1291 addScopeVariable(Scope, new DbgVariable(DV, nullptr, this));
1292 }
1293 }
1295 // Return Label preceding the instruction.
1296 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1297 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1298 assert(Label && "Didn't insert label before instruction");
1299 return Label;
1300 }
1302 // Return Label immediately following the instruction.
1303 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1304 return LabelsAfterInsn.lookup(MI);
1305 }
1307 // Process beginning of an instruction.
1308 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1309 assert(CurMI == nullptr);
1310 CurMI = MI;
1311 // Check if source location changes, but ignore DBG_VALUE locations.
1312 if (!MI->isDebugValue()) {
1313 DebugLoc DL = MI->getDebugLoc();
1314 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1315 unsigned Flags = 0;
1316 PrevInstLoc = DL;
1317 if (DL == PrologEndLoc) {
1318 Flags |= DWARF2_FLAG_PROLOGUE_END;
1319 PrologEndLoc = DebugLoc();
1320 }
1321 if (PrologEndLoc.isUnknown())
1322 Flags |= DWARF2_FLAG_IS_STMT;
1324 if (!DL.isUnknown()) {
1325 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1326 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1327 } else
1328 recordSourceLine(0, 0, nullptr, 0);
1329 }
1330 }
1332 // Insert labels where requested.
1333 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1334 LabelsBeforeInsn.find(MI);
1336 // No label needed.
1337 if (I == LabelsBeforeInsn.end())
1338 return;
1340 // Label already assigned.
1341 if (I->second)
1342 return;
1344 if (!PrevLabel) {
1345 PrevLabel = MMI->getContext().CreateTempSymbol();
1346 Asm->OutStreamer.EmitLabel(PrevLabel);
1347 }
1348 I->second = PrevLabel;
1349 }
1351 // Process end of an instruction.
1352 void DwarfDebug::endInstruction() {
1353 assert(CurMI != nullptr);
1354 // Don't create a new label after DBG_VALUE instructions.
1355 // They don't generate code.
1356 if (!CurMI->isDebugValue())
1357 PrevLabel = nullptr;
1359 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1360 LabelsAfterInsn.find(CurMI);
1361 CurMI = nullptr;
1363 // No label needed.
1364 if (I == LabelsAfterInsn.end())
1365 return;
1367 // Label already assigned.
1368 if (I->second)
1369 return;
1371 // We need a label after this instruction.
1372 if (!PrevLabel) {
1373 PrevLabel = MMI->getContext().CreateTempSymbol();
1374 Asm->OutStreamer.EmitLabel(PrevLabel);
1375 }
1376 I->second = PrevLabel;
1377 }
1379 // Each LexicalScope has first instruction and last instruction to mark
1380 // beginning and end of a scope respectively. Create an inverse map that list
1381 // scopes starts (and ends) with an instruction. One instruction may start (or
1382 // end) multiple scopes. Ignore scopes that are not reachable.
1383 void DwarfDebug::identifyScopeMarkers() {
1384 SmallVector<LexicalScope *, 4> WorkList;
1385 WorkList.push_back(LScopes.getCurrentFunctionScope());
1386 while (!WorkList.empty()) {
1387 LexicalScope *S = WorkList.pop_back_val();
1389 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1390 if (!Children.empty())
1391 WorkList.append(Children.begin(), Children.end());
1393 if (S->isAbstractScope())
1394 continue;
1396 for (const InsnRange &R : S->getRanges()) {
1397 assert(R.first && "InsnRange does not have first instruction!");
1398 assert(R.second && "InsnRange does not have second instruction!");
1399 requestLabelBeforeInsn(R.first);
1400 requestLabelAfterInsn(R.second);
1401 }
1402 }
1403 }
1405 // Gather pre-function debug information. Assumes being called immediately
1406 // after the function entry point has been emitted.
1407 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1408 CurFn = MF;
1410 // If there's no debug info for the function we're not going to do anything.
1411 if (!MMI->hasDebugInfo())
1412 return;
1414 // Grab the lexical scopes for the function, if we don't have any of those
1415 // then we're not going to be able to do anything.
1416 LScopes.initialize(*MF);
1417 if (LScopes.empty())
1418 return;
1420 assert(UserVariables.empty() && DbgValues.empty() && "Maps weren't cleaned");
1422 // Make sure that each lexical scope will have a begin/end label.
1423 identifyScopeMarkers();
1425 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1426 // belongs to so that we add to the correct per-cu line table in the
1427 // non-asm case.
1428 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1429 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1430 assert(TheCU && "Unable to find compile unit!");
1431 if (Asm->OutStreamer.hasRawTextSupport())
1432 // Use a single line table if we are generating assembly.
1433 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1434 else
1435 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1437 // Emit a label for the function so that we have a beginning address.
1438 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1439 // Assumes in correct section after the entry point.
1440 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1442 // Collect user variables, find the end of the prologue.
1443 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
1444 ++I) {
1445 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
1446 II != IE; ++II) {
1447 const MachineInstr *MI = II;
1448 if (MI->isDebugValue()) {
1449 assert(MI->getNumOperands() > 1 && "Invalid machine instruction!");
1450 // Keep track of user variables in order of appearance. Store the set
1451 // of variables we've already seen as a set of keys in DbgValues.
1452 const MDNode *Var = MI->getDebugVariable();
1453 auto IterPair = DbgValues.insert(
1454 std::make_pair(Var, SmallVector<const MachineInstr *, 4>()));
1455 if (IterPair.second)
1456 UserVariables.push_back(Var);
1457 } else {
1458 // First known non-DBG_VALUE and non-frame setup location marks
1459 // the beginning of the function body.
1460 if (!MI->getFlag(MachineInstr::FrameSetup) &&
1461 (PrologEndLoc.isUnknown() && !MI->getDebugLoc().isUnknown()))
1462 PrologEndLoc = MI->getDebugLoc();
1463 }
1464 }
1465 }
1467 // Calculate history for local variables.
1468 calculateDbgValueHistory(MF, Asm->TM.getRegisterInfo(), DbgValues);
1470 // Request labels for the full history.
1471 for (auto &I : DbgValues) {
1472 const SmallVectorImpl<const MachineInstr *> &History = I.second;
1473 if (History.empty())
1474 continue;
1476 // The first mention of a function argument gets the FunctionBeginSym
1477 // label, so arguments are visible when breaking at function entry.
1478 DIVariable DV(I.first);
1479 if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
1480 getDISubprogram(DV.getContext()).describes(MF->getFunction()))
1481 LabelsBeforeInsn[History.front()] = FunctionBeginSym;
1483 for (const MachineInstr *MI : History) {
1484 if (MI->isDebugValue())
1485 requestLabelBeforeInsn(MI);
1486 else
1487 requestLabelAfterInsn(MI);
1488 }
1489 }
1491 PrevInstLoc = DebugLoc();
1492 PrevLabel = FunctionBeginSym;
1494 // Record beginning of function.
1495 if (!PrologEndLoc.isUnknown()) {
1496 DebugLoc FnStartDL =
1497 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1498 recordSourceLine(
1499 FnStartDL.getLine(), FnStartDL.getCol(),
1500 FnStartDL.getScope(MF->getFunction()->getContext()),
1501 // We'd like to list the prologue as "not statements" but GDB behaves
1502 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1503 DWARF2_FLAG_IS_STMT);
1504 }
1505 }
1507 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1508 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1509 DIVariable DV = Var->getVariable();
1510 // Variables with positive arg numbers are parameters.
1511 if (unsigned ArgNum = DV.getArgNumber()) {
1512 // Keep all parameters in order at the start of the variable list to ensure
1513 // function types are correct (no out-of-order parameters)
1514 //
1515 // This could be improved by only doing it for optimized builds (unoptimized
1516 // builds have the right order to begin with), searching from the back (this
1517 // would catch the unoptimized case quickly), or doing a binary search
1518 // rather than linear search.
1519 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1520 while (I != Vars.end()) {
1521 unsigned CurNum = (*I)->getVariable().getArgNumber();
1522 // A local (non-parameter) variable has been found, insert immediately
1523 // before it.
1524 if (CurNum == 0)
1525 break;
1526 // A later indexed parameter has been found, insert immediately before it.
1527 if (CurNum > ArgNum)
1528 break;
1529 ++I;
1530 }
1531 Vars.insert(I, Var);
1532 return;
1533 }
1535 Vars.push_back(Var);
1536 }
1538 // Gather and emit post-function debug information.
1539 void DwarfDebug::endFunction(const MachineFunction *MF) {
1540 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1541 // though the beginFunction may not be called at all.
1542 // We should handle both cases.
1543 if (!CurFn)
1544 CurFn = MF;
1545 else
1546 assert(CurFn == MF);
1547 assert(CurFn != nullptr);
1549 if (!MMI->hasDebugInfo() || LScopes.empty()) {
1550 // If we don't have a lexical scope for this function then there will
1551 // be a hole in the range information. Keep note of this by setting the
1552 // previously used section to nullptr.
1553 PrevSection = nullptr;
1554 PrevCU = nullptr;
1555 CurFn = nullptr;
1556 return;
1557 }
1559 // Define end label for subprogram.
1560 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1561 // Assumes in correct section after the entry point.
1562 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1564 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1565 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1567 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1568 collectVariableInfo(ProcessedVars);
1570 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1571 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1573 // Construct abstract scopes.
1574 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1575 DISubprogram SP(AScope->getScopeNode());
1576 if (SP.isSubprogram()) {
1577 // Collect info for variables that were optimized out.
1578 DIArray Variables = SP.getVariables();
1579 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1580 DIVariable DV(Variables.getElement(i));
1581 if (!DV || !DV.isVariable() || !ProcessedVars.insert(DV))
1582 continue;
1583 // Check that DbgVariable for DV wasn't created earlier, when
1584 // findAbstractVariable() was called for inlined instance of DV.
1585 LLVMContext &Ctx = DV->getContext();
1586 DIVariable CleanDV = cleanseInlinedVariable(DV, Ctx);
1587 if (AbstractVariables.lookup(CleanDV))
1588 continue;
1589 if (LexicalScope *Scope = LScopes.findAbstractScope(DV.getContext()))
1590 addScopeVariable(Scope, new DbgVariable(DV, nullptr, this));
1591 }
1592 }
1593 if (ProcessedSPNodes.count(AScope->getScopeNode()) == 0)
1594 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1595 }
1597 DIE &CurFnDIE = constructSubprogramScopeDIE(TheCU, FnScope);
1598 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
1599 TheCU.addFlag(CurFnDIE, dwarf::DW_AT_APPLE_omit_frame_ptr);
1601 // Add the range of this function to the list of ranges for the CU.
1602 RangeSpan Span(FunctionBeginSym, FunctionEndSym);
1603 TheCU.addRange(std::move(Span));
1604 PrevSection = Asm->getCurrentSection();
1605 PrevCU = &TheCU;
1607 // Clear debug info
1608 for (auto &I : ScopeVariables)
1609 DeleteContainerPointers(I.second);
1610 ScopeVariables.clear();
1611 DeleteContainerPointers(CurrentFnArguments);
1612 UserVariables.clear();
1613 DbgValues.clear();
1614 AbstractVariables.clear();
1615 LabelsBeforeInsn.clear();
1616 LabelsAfterInsn.clear();
1617 PrevLabel = nullptr;
1618 CurFn = nullptr;
1619 }
1621 // Register a source line with debug info. Returns the unique label that was
1622 // emitted and which provides correspondence to the source line list.
1623 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1624 unsigned Flags) {
1625 StringRef Fn;
1626 StringRef Dir;
1627 unsigned Src = 1;
1628 unsigned Discriminator = 0;
1629 if (S) {
1630 DIDescriptor Scope(S);
1632 if (Scope.isCompileUnit()) {
1633 DICompileUnit CU(S);
1634 Fn = CU.getFilename();
1635 Dir = CU.getDirectory();
1636 } else if (Scope.isFile()) {
1637 DIFile F(S);
1638 Fn = F.getFilename();
1639 Dir = F.getDirectory();
1640 } else if (Scope.isSubprogram()) {
1641 DISubprogram SP(S);
1642 Fn = SP.getFilename();
1643 Dir = SP.getDirectory();
1644 } else if (Scope.isLexicalBlockFile()) {
1645 DILexicalBlockFile DBF(S);
1646 Fn = DBF.getFilename();
1647 Dir = DBF.getDirectory();
1648 } else if (Scope.isLexicalBlock()) {
1649 DILexicalBlock DB(S);
1650 Fn = DB.getFilename();
1651 Dir = DB.getDirectory();
1652 Discriminator = DB.getDiscriminator();
1653 } else
1654 llvm_unreachable("Unexpected scope info");
1656 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1657 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1658 .getOrCreateSourceID(Fn, Dir);
1659 }
1660 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1661 Discriminator, Fn);
1662 }
1664 //===----------------------------------------------------------------------===//
1665 // Emit Methods
1666 //===----------------------------------------------------------------------===//
1668 // Emit initial Dwarf sections with a label at the start of each one.
1669 void DwarfDebug::emitSectionLabels() {
1670 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1672 // Dwarf sections base addresses.
1673 DwarfInfoSectionSym =
1674 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1675 if (useSplitDwarf())
1676 DwarfInfoDWOSectionSym =
1677 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1678 DwarfAbbrevSectionSym =
1679 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1680 if (useSplitDwarf())
1681 DwarfAbbrevDWOSectionSym = emitSectionSym(
1682 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1683 if (GenerateARangeSection)
1684 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1686 DwarfLineSectionSym =
1687 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1688 if (GenerateGnuPubSections) {
1689 DwarfGnuPubNamesSectionSym =
1690 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1691 DwarfGnuPubTypesSectionSym =
1692 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1693 } else if (HasDwarfPubSections) {
1694 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1695 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1696 }
1698 DwarfStrSectionSym =
1699 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1700 if (useSplitDwarf()) {
1701 DwarfStrDWOSectionSym =
1702 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1703 DwarfAddrSectionSym =
1704 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1705 DwarfDebugLocSectionSym =
1706 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1707 } else
1708 DwarfDebugLocSectionSym =
1709 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1710 DwarfDebugRangeSectionSym =
1711 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1712 }
1714 // Recursively emits a debug information entry.
1715 void DwarfDebug::emitDIE(DIE &Die) {
1716 // Get the abbreviation for this DIE.
1717 const DIEAbbrev &Abbrev = Die.getAbbrev();
1719 // Emit the code (index) for the abbreviation.
1720 if (Asm->isVerbose())
1721 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1722 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1723 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1724 dwarf::TagString(Abbrev.getTag()));
1725 Asm->EmitULEB128(Abbrev.getNumber());
1727 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1728 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1730 // Emit the DIE attribute values.
1731 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1732 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1733 dwarf::Form Form = AbbrevData[i].getForm();
1734 assert(Form && "Too many attributes for DIE (check abbreviation)");
1736 if (Asm->isVerbose()) {
1737 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1738 if (Attr == dwarf::DW_AT_accessibility)
1739 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1740 cast<DIEInteger>(Values[i])->getValue()));
1741 }
1743 // Emit an attribute using the defined form.
1744 Values[i]->EmitValue(Asm, Form);
1745 }
1747 // Emit the DIE children if any.
1748 if (Abbrev.hasChildren()) {
1749 for (auto &Child : Die.getChildren())
1750 emitDIE(*Child);
1752 Asm->OutStreamer.AddComment("End Of Children Mark");
1753 Asm->EmitInt8(0);
1754 }
1755 }
1757 // Emit the debug info section.
1758 void DwarfDebug::emitDebugInfo() {
1759 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1761 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1762 }
1764 // Emit the abbreviation section.
1765 void DwarfDebug::emitAbbreviations() {
1766 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1768 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1769 }
1771 // Emit the last address of the section and the end of the line matrix.
1772 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1773 // Define last address of section.
1774 Asm->OutStreamer.AddComment("Extended Op");
1775 Asm->EmitInt8(0);
1777 Asm->OutStreamer.AddComment("Op size");
1778 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1779 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1780 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1782 Asm->OutStreamer.AddComment("Section end label");
1784 Asm->OutStreamer.EmitSymbolValue(
1785 Asm->GetTempSymbol("section_end", SectionEnd),
1786 Asm->getDataLayout().getPointerSize());
1788 // Mark end of matrix.
1789 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1790 Asm->EmitInt8(0);
1791 Asm->EmitInt8(1);
1792 Asm->EmitInt8(1);
1793 }
1795 // Emit visible names into a hashed accelerator table section.
1796 void DwarfDebug::emitAccelNames() {
1797 AccelNames.FinalizeTable(Asm, "Names");
1798 Asm->OutStreamer.SwitchSection(
1799 Asm->getObjFileLowering().getDwarfAccelNamesSection());
1800 MCSymbol *SectionBegin = Asm->GetTempSymbol("names_begin");
1801 Asm->OutStreamer.EmitLabel(SectionBegin);
1803 // Emit the full data.
1804 AccelNames.Emit(Asm, SectionBegin, &InfoHolder);
1805 }
1807 // Emit objective C classes and categories into a hashed accelerator table
1808 // section.
1809 void DwarfDebug::emitAccelObjC() {
1810 AccelObjC.FinalizeTable(Asm, "ObjC");
1811 Asm->OutStreamer.SwitchSection(
1812 Asm->getObjFileLowering().getDwarfAccelObjCSection());
1813 MCSymbol *SectionBegin = Asm->GetTempSymbol("objc_begin");
1814 Asm->OutStreamer.EmitLabel(SectionBegin);
1816 // Emit the full data.
1817 AccelObjC.Emit(Asm, SectionBegin, &InfoHolder);
1818 }
1820 // Emit namespace dies into a hashed accelerator table.
1821 void DwarfDebug::emitAccelNamespaces() {
1822 AccelNamespace.FinalizeTable(Asm, "namespac");
1823 Asm->OutStreamer.SwitchSection(
1824 Asm->getObjFileLowering().getDwarfAccelNamespaceSection());
1825 MCSymbol *SectionBegin = Asm->GetTempSymbol("namespac_begin");
1826 Asm->OutStreamer.EmitLabel(SectionBegin);
1828 // Emit the full data.
1829 AccelNamespace.Emit(Asm, SectionBegin, &InfoHolder);
1830 }
1832 // Emit type dies into a hashed accelerator table.
1833 void DwarfDebug::emitAccelTypes() {
1835 AccelTypes.FinalizeTable(Asm, "types");
1836 Asm->OutStreamer.SwitchSection(
1837 Asm->getObjFileLowering().getDwarfAccelTypesSection());
1838 MCSymbol *SectionBegin = Asm->GetTempSymbol("types_begin");
1839 Asm->OutStreamer.EmitLabel(SectionBegin);
1841 // Emit the full data.
1842 AccelTypes.Emit(Asm, SectionBegin, &InfoHolder);
1843 }
1845 // Public name handling.
1846 // The format for the various pubnames:
1847 //
1848 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1849 // for the DIE that is named.
1850 //
1851 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1852 // into the CU and the index value is computed according to the type of value
1853 // for the DIE that is named.
1854 //
1855 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1856 // it's the offset within the debug_info/debug_types dwo section, however, the
1857 // reference in the pubname header doesn't change.
1859 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1860 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1861 const DIE *Die) {
1862 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1864 // We could have a specification DIE that has our most of our knowledge,
1865 // look for that now.
1866 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1867 if (SpecVal) {
1868 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1869 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1870 Linkage = dwarf::GIEL_EXTERNAL;
1871 } else if (Die->findAttribute(dwarf::DW_AT_external))
1872 Linkage = dwarf::GIEL_EXTERNAL;
1874 switch (Die->getTag()) {
1875 case dwarf::DW_TAG_class_type:
1876 case dwarf::DW_TAG_structure_type:
1877 case dwarf::DW_TAG_union_type:
1878 case dwarf::DW_TAG_enumeration_type:
1879 return dwarf::PubIndexEntryDescriptor(
1880 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1881 ? dwarf::GIEL_STATIC
1882 : dwarf::GIEL_EXTERNAL);
1883 case dwarf::DW_TAG_typedef:
1884 case dwarf::DW_TAG_base_type:
1885 case dwarf::DW_TAG_subrange_type:
1886 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1887 case dwarf::DW_TAG_namespace:
1888 return dwarf::GIEK_TYPE;
1889 case dwarf::DW_TAG_subprogram:
1890 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1891 case dwarf::DW_TAG_constant:
1892 case dwarf::DW_TAG_variable:
1893 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1894 case dwarf::DW_TAG_enumerator:
1895 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1896 dwarf::GIEL_STATIC);
1897 default:
1898 return dwarf::GIEK_NONE;
1899 }
1900 }
1902 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1903 ///
1904 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1905 const MCSection *PSec =
1906 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1907 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1909 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1910 }
1912 void DwarfDebug::emitDebugPubSection(
1913 bool GnuStyle, const MCSection *PSec, StringRef Name,
1914 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1915 for (const auto &NU : CUMap) {
1916 DwarfCompileUnit *TheU = NU.second;
1918 const auto &Globals = (TheU->*Accessor)();
1920 if (Globals.empty())
1921 continue;
1923 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1924 TheU = Skeleton;
1925 unsigned ID = TheU->getUniqueID();
1927 // Start the dwarf pubnames section.
1928 Asm->OutStreamer.SwitchSection(PSec);
1930 // Emit the header.
1931 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1932 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1933 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1934 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1936 Asm->OutStreamer.EmitLabel(BeginLabel);
1938 Asm->OutStreamer.AddComment("DWARF Version");
1939 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1941 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1942 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1944 Asm->OutStreamer.AddComment("Compilation Unit Length");
1945 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1947 // Emit the pubnames for this compilation unit.
1948 for (const auto &GI : Globals) {
1949 const char *Name = GI.getKeyData();
1950 const DIE *Entity = GI.second;
1952 Asm->OutStreamer.AddComment("DIE offset");
1953 Asm->EmitInt32(Entity->getOffset());
1955 if (GnuStyle) {
1956 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1957 Asm->OutStreamer.AddComment(
1958 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1959 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1960 Asm->EmitInt8(Desc.toBits());
1961 }
1963 Asm->OutStreamer.AddComment("External Name");
1964 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1965 }
1967 Asm->OutStreamer.AddComment("End Mark");
1968 Asm->EmitInt32(0);
1969 Asm->OutStreamer.EmitLabel(EndLabel);
1970 }
1971 }
1973 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1974 const MCSection *PSec =
1975 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1976 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1978 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1979 }
1981 // Emit visible names into a debug str section.
1982 void DwarfDebug::emitDebugStr() {
1983 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1984 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1985 }
1987 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1988 const DebugLocEntry &Entry) {
1989 assert(Entry.getValues().size() == 1 &&
1990 "multi-value entries are not supported yet.");
1991 const DebugLocEntry::Value Value = Entry.getValues()[0];
1992 DIVariable DV(Value.getVariable());
1993 if (Value.isInt()) {
1994 DIBasicType BTy(resolve(DV.getType()));
1995 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1996 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1997 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1998 Streamer.EmitSLEB128(Value.getInt());
1999 } else {
2000 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
2001 Streamer.EmitULEB128(Value.getInt());
2002 }
2003 } else if (Value.isLocation()) {
2004 MachineLocation Loc = Value.getLoc();
2005 if (!DV.hasComplexAddress())
2006 // Regular entry.
2007 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2008 else {
2009 // Complex address entry.
2010 unsigned N = DV.getNumAddrElements();
2011 unsigned i = 0;
2012 if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
2013 if (Loc.getOffset()) {
2014 i = 2;
2015 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2016 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2017 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2018 Streamer.EmitSLEB128(DV.getAddrElement(1));
2019 } else {
2020 // If first address element is OpPlus then emit
2021 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
2022 MachineLocation TLoc(Loc.getReg(), DV.getAddrElement(1));
2023 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
2024 i = 2;
2025 }
2026 } else {
2027 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2028 }
2030 // Emit remaining complex address elements.
2031 for (; i < N; ++i) {
2032 uint64_t Element = DV.getAddrElement(i);
2033 if (Element == DIBuilder::OpPlus) {
2034 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2035 Streamer.EmitULEB128(DV.getAddrElement(++i));
2036 } else if (Element == DIBuilder::OpDeref) {
2037 if (!Loc.isReg())
2038 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2039 } else
2040 llvm_unreachable("unknown Opcode found in complex address");
2041 }
2042 }
2043 }
2044 // else ... ignore constant fp. There is not any good way to
2045 // to represent them here in dwarf.
2046 // FIXME: ^
2047 }
2049 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
2050 Asm->OutStreamer.AddComment("Loc expr size");
2051 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
2052 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
2053 Asm->EmitLabelDifference(end, begin, 2);
2054 Asm->OutStreamer.EmitLabel(begin);
2055 // Emit the entry.
2056 APByteStreamer Streamer(*Asm);
2057 emitDebugLocEntry(Streamer, Entry);
2058 // Close the range.
2059 Asm->OutStreamer.EmitLabel(end);
2060 }
2062 // Emit locations into the debug loc section.
2063 void DwarfDebug::emitDebugLoc() {
2064 // Start the dwarf loc section.
2065 Asm->OutStreamer.SwitchSection(
2066 Asm->getObjFileLowering().getDwarfLocSection());
2067 unsigned char Size = Asm->getDataLayout().getPointerSize();
2068 for (const auto &DebugLoc : DotDebugLocEntries) {
2069 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2070 for (const auto &Entry : DebugLoc.List) {
2071 // Set up the range. This range is relative to the entry point of the
2072 // compile unit. This is a hard coded 0 for low_pc when we're emitting
2073 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
2074 const DwarfCompileUnit *CU = Entry.getCU();
2075 if (CU->getRanges().size() == 1) {
2076 // Grab the begin symbol from the first range as our base.
2077 const MCSymbol *Base = CU->getRanges()[0].getStart();
2078 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
2079 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
2080 } else {
2081 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
2082 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
2083 }
2085 emitDebugLocEntryLocation(Entry);
2086 }
2087 Asm->OutStreamer.EmitIntValue(0, Size);
2088 Asm->OutStreamer.EmitIntValue(0, Size);
2089 }
2090 }
2092 void DwarfDebug::emitDebugLocDWO() {
2093 Asm->OutStreamer.SwitchSection(
2094 Asm->getObjFileLowering().getDwarfLocDWOSection());
2095 for (const auto &DebugLoc : DotDebugLocEntries) {
2096 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2097 for (const auto &Entry : DebugLoc.List) {
2098 // Just always use start_length for now - at least that's one address
2099 // rather than two. We could get fancier and try to, say, reuse an
2100 // address we know we've emitted elsewhere (the start of the function?
2101 // The start of the CU or CU subrange that encloses this range?)
2102 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2103 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2104 Asm->EmitULEB128(idx);
2105 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2107 emitDebugLocEntryLocation(Entry);
2108 }
2109 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2110 }
2111 }
2113 struct ArangeSpan {
2114 const MCSymbol *Start, *End;
2115 };
2117 // Emit a debug aranges section, containing a CU lookup for any
2118 // address we can tie back to a CU.
2119 void DwarfDebug::emitDebugARanges() {
2120 // Start the dwarf aranges section.
2121 Asm->OutStreamer.SwitchSection(
2122 Asm->getObjFileLowering().getDwarfARangesSection());
2124 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2126 SpansType Spans;
2128 // Build a list of sections used.
2129 std::vector<const MCSection *> Sections;
2130 for (const auto &it : SectionMap) {
2131 const MCSection *Section = it.first;
2132 Sections.push_back(Section);
2133 }
2135 // Sort the sections into order.
2136 // This is only done to ensure consistent output order across different runs.
2137 std::sort(Sections.begin(), Sections.end(), SectionSort);
2139 // Build a set of address spans, sorted by CU.
2140 for (const MCSection *Section : Sections) {
2141 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2142 if (List.size() < 2)
2143 continue;
2145 // Sort the symbols by offset within the section.
2146 std::sort(List.begin(), List.end(),
2147 [&](const SymbolCU &A, const SymbolCU &B) {
2148 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2149 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2151 // Symbols with no order assigned should be placed at the end.
2152 // (e.g. section end labels)
2153 if (IA == 0)
2154 return false;
2155 if (IB == 0)
2156 return true;
2157 return IA < IB;
2158 });
2160 // If we have no section (e.g. common), just write out
2161 // individual spans for each symbol.
2162 if (!Section) {
2163 for (const SymbolCU &Cur : List) {
2164 ArangeSpan Span;
2165 Span.Start = Cur.Sym;
2166 Span.End = nullptr;
2167 if (Cur.CU)
2168 Spans[Cur.CU].push_back(Span);
2169 }
2170 } else {
2171 // Build spans between each label.
2172 const MCSymbol *StartSym = List[0].Sym;
2173 for (size_t n = 1, e = List.size(); n < e; n++) {
2174 const SymbolCU &Prev = List[n - 1];
2175 const SymbolCU &Cur = List[n];
2177 // Try and build the longest span we can within the same CU.
2178 if (Cur.CU != Prev.CU) {
2179 ArangeSpan Span;
2180 Span.Start = StartSym;
2181 Span.End = Cur.Sym;
2182 Spans[Prev.CU].push_back(Span);
2183 StartSym = Cur.Sym;
2184 }
2185 }
2186 }
2187 }
2189 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2191 // Build a list of CUs used.
2192 std::vector<DwarfCompileUnit *> CUs;
2193 for (const auto &it : Spans) {
2194 DwarfCompileUnit *CU = it.first;
2195 CUs.push_back(CU);
2196 }
2198 // Sort the CU list (again, to ensure consistent output order).
2199 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2200 return A->getUniqueID() < B->getUniqueID();
2201 });
2203 // Emit an arange table for each CU we used.
2204 for (DwarfCompileUnit *CU : CUs) {
2205 std::vector<ArangeSpan> &List = Spans[CU];
2207 // Emit size of content not including length itself.
2208 unsigned ContentSize =
2209 sizeof(int16_t) + // DWARF ARange version number
2210 sizeof(int32_t) + // Offset of CU in the .debug_info section
2211 sizeof(int8_t) + // Pointer Size (in bytes)
2212 sizeof(int8_t); // Segment Size (in bytes)
2214 unsigned TupleSize = PtrSize * 2;
2216 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2217 unsigned Padding =
2218 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2220 ContentSize += Padding;
2221 ContentSize += (List.size() + 1) * TupleSize;
2223 // For each compile unit, write the list of spans it covers.
2224 Asm->OutStreamer.AddComment("Length of ARange Set");
2225 Asm->EmitInt32(ContentSize);
2226 Asm->OutStreamer.AddComment("DWARF Arange version number");
2227 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2228 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2229 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2230 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2231 Asm->EmitInt8(PtrSize);
2232 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2233 Asm->EmitInt8(0);
2235 Asm->OutStreamer.EmitFill(Padding, 0xff);
2237 for (const ArangeSpan &Span : List) {
2238 Asm->EmitLabelReference(Span.Start, PtrSize);
2240 // Calculate the size as being from the span start to it's end.
2241 if (Span.End) {
2242 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2243 } else {
2244 // For symbols without an end marker (e.g. common), we
2245 // write a single arange entry containing just that one symbol.
2246 uint64_t Size = SymSize[Span.Start];
2247 if (Size == 0)
2248 Size = 1;
2250 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2251 }
2252 }
2254 Asm->OutStreamer.AddComment("ARange terminator");
2255 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2256 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2257 }
2258 }
2260 // Emit visible names into a debug ranges section.
2261 void DwarfDebug::emitDebugRanges() {
2262 // Start the dwarf ranges section.
2263 Asm->OutStreamer.SwitchSection(
2264 Asm->getObjFileLowering().getDwarfRangesSection());
2266 // Size for our labels.
2267 unsigned char Size = Asm->getDataLayout().getPointerSize();
2269 // Grab the specific ranges for the compile units in the module.
2270 for (const auto &I : CUMap) {
2271 DwarfCompileUnit *TheCU = I.second;
2273 // Iterate over the misc ranges for the compile units in the module.
2274 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2275 // Emit our symbol so we can find the beginning of the range.
2276 Asm->OutStreamer.EmitLabel(List.getSym());
2278 for (const RangeSpan &Range : List.getRanges()) {
2279 const MCSymbol *Begin = Range.getStart();
2280 const MCSymbol *End = Range.getEnd();
2281 assert(Begin && "Range without a begin symbol?");
2282 assert(End && "Range without an end symbol?");
2283 if (TheCU->getRanges().size() == 1) {
2284 // Grab the begin symbol from the first range as our base.
2285 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2286 Asm->EmitLabelDifference(Begin, Base, Size);
2287 Asm->EmitLabelDifference(End, Base, Size);
2288 } else {
2289 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2290 Asm->OutStreamer.EmitSymbolValue(End, Size);
2291 }
2292 }
2294 // And terminate the list with two 0 values.
2295 Asm->OutStreamer.EmitIntValue(0, Size);
2296 Asm->OutStreamer.EmitIntValue(0, Size);
2297 }
2299 // Now emit a range for the CU itself.
2300 if (TheCU->getRanges().size() > 1) {
2301 Asm->OutStreamer.EmitLabel(
2302 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2303 for (const RangeSpan &Range : TheCU->getRanges()) {
2304 const MCSymbol *Begin = Range.getStart();
2305 const MCSymbol *End = Range.getEnd();
2306 assert(Begin && "Range without a begin symbol?");
2307 assert(End && "Range without an end symbol?");
2308 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2309 Asm->OutStreamer.EmitSymbolValue(End, Size);
2310 }
2311 // And terminate the list with two 0 values.
2312 Asm->OutStreamer.EmitIntValue(0, Size);
2313 Asm->OutStreamer.EmitIntValue(0, Size);
2314 }
2315 }
2316 }
2318 // DWARF5 Experimental Separate Dwarf emitters.
2320 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2321 std::unique_ptr<DwarfUnit> NewU) {
2322 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2323 U.getCUNode().getSplitDebugFilename());
2325 if (!CompilationDir.empty())
2326 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2328 addGnuPubAttributes(*NewU, Die);
2330 SkeletonHolder.addUnit(std::move(NewU));
2331 }
2333 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2334 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2335 // DW_AT_addr_base, DW_AT_ranges_base.
2336 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2338 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2339 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2340 DwarfCompileUnit &NewCU = *OwnedUnit;
2341 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2342 DwarfInfoSectionSym);
2344 NewCU.initStmtList(DwarfLineSectionSym);
2346 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2348 return NewCU;
2349 }
2351 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_dwo_name,
2352 // DW_AT_addr_base.
2353 DwarfTypeUnit &DwarfDebug::constructSkeletonTU(DwarfTypeUnit &TU) {
2354 DwarfCompileUnit &CU = static_cast<DwarfCompileUnit &>(
2355 *SkeletonHolder.getUnits()[TU.getCU().getUniqueID()]);
2357 auto OwnedUnit = make_unique<DwarfTypeUnit>(TU.getUniqueID(), CU, Asm, this,
2358 &SkeletonHolder);
2359 DwarfTypeUnit &NewTU = *OwnedUnit;
2360 NewTU.setTypeSignature(TU.getTypeSignature());
2361 NewTU.setType(nullptr);
2362 NewTU.initSection(
2363 Asm->getObjFileLowering().getDwarfTypesSection(TU.getTypeSignature()));
2365 initSkeletonUnit(TU, NewTU.getUnitDie(), std::move(OwnedUnit));
2366 return NewTU;
2367 }
2369 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2370 // compile units that would normally be in debug_info.
2371 void DwarfDebug::emitDebugInfoDWO() {
2372 assert(useSplitDwarf() && "No split dwarf debug info?");
2373 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2374 // emit relocations into the dwo file.
2375 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2376 }
2378 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2379 // abbreviations for the .debug_info.dwo section.
2380 void DwarfDebug::emitDebugAbbrevDWO() {
2381 assert(useSplitDwarf() && "No split dwarf?");
2382 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2383 }
2385 void DwarfDebug::emitDebugLineDWO() {
2386 assert(useSplitDwarf() && "No split dwarf?");
2387 Asm->OutStreamer.SwitchSection(
2388 Asm->getObjFileLowering().getDwarfLineDWOSection());
2389 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2390 }
2392 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2393 // string section and is identical in format to traditional .debug_str
2394 // sections.
2395 void DwarfDebug::emitDebugStrDWO() {
2396 assert(useSplitDwarf() && "No split dwarf?");
2397 const MCSection *OffSec =
2398 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2399 const MCSymbol *StrSym = DwarfStrSectionSym;
2400 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2401 OffSec, StrSym);
2402 }
2404 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2405 if (!useSplitDwarf())
2406 return nullptr;
2407 if (SingleCU)
2408 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2409 return &SplitTypeUnitFileTable;
2410 }
2412 static uint64_t makeTypeSignature(StringRef Identifier) {
2413 MD5 Hash;
2414 Hash.update(Identifier);
2415 // ... take the least significant 8 bytes and return those. Our MD5
2416 // implementation always returns its results in little endian, swap bytes
2417 // appropriately.
2418 MD5::MD5Result Result;
2419 Hash.final(Result);
2420 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2421 }
2423 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2424 StringRef Identifier, DIE &RefDie,
2425 DICompositeType CTy) {
2426 // Fast path if we're building some type units and one has already used the
2427 // address pool we know we're going to throw away all this work anyway, so
2428 // don't bother building dependent types.
2429 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2430 return;
2432 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2433 if (TU) {
2434 CU.addDIETypeSignature(RefDie, *TU);
2435 return;
2436 }
2438 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2439 AddrPool.resetUsedFlag();
2441 auto OwnedUnit =
2442 make_unique<DwarfTypeUnit>(InfoHolder.getUnits().size(), CU, Asm, this,
2443 &InfoHolder, getDwoLineTable(CU));
2444 DwarfTypeUnit &NewTU = *OwnedUnit;
2445 DIE &UnitDie = NewTU.getUnitDie();
2446 TU = &NewTU;
2447 TypeUnitsUnderConstruction.push_back(
2448 std::make_pair(std::move(OwnedUnit), CTy));
2450 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2451 CU.getLanguage());
2453 uint64_t Signature = makeTypeSignature(Identifier);
2454 NewTU.setTypeSignature(Signature);
2456 if (!useSplitDwarf())
2457 CU.applyStmtList(UnitDie);
2459 NewTU.initSection(
2460 useSplitDwarf()
2461 ? Asm->getObjFileLowering().getDwarfTypesDWOSection(Signature)
2462 : Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2464 NewTU.setType(NewTU.createTypeDIE(CTy));
2466 if (TopLevelType) {
2467 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2468 TypeUnitsUnderConstruction.clear();
2470 // Types referencing entries in the address table cannot be placed in type
2471 // units.
2472 if (AddrPool.hasBeenUsed()) {
2474 // Remove all the types built while building this type.
2475 // This is pessimistic as some of these types might not be dependent on
2476 // the type that used an address.
2477 for (const auto &TU : TypeUnitsToAdd)
2478 DwarfTypeUnits.erase(TU.second);
2480 // Construct this type in the CU directly.
2481 // This is inefficient because all the dependent types will be rebuilt
2482 // from scratch, including building them in type units, discovering that
2483 // they depend on addresses, throwing them out and rebuilding them.
2484 CU.constructTypeDIE(RefDie, CTy);
2485 return;
2486 }
2488 // If the type wasn't dependent on fission addresses, finish adding the type
2489 // and all its dependent types.
2490 for (auto &TU : TypeUnitsToAdd) {
2491 if (useSplitDwarf())
2492 TU.first->setSkeleton(constructSkeletonTU(*TU.first));
2493 InfoHolder.addUnit(std::move(TU.first));
2494 }
2495 }
2496 CU.addDIETypeSignature(RefDie, NewTU);
2497 }
2499 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2500 MCSymbol *Begin, MCSymbol *End) {
2501 Unit.addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
2502 if (DwarfVersion < 4)
2503 Unit.addLabelAddress(D, dwarf::DW_AT_high_pc, End);
2504 else
2505 Unit.addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
2506 }
2508 // Accelerator table mutators - add each name along with its companion
2509 // DIE to the proper table while ensuring that the name that we're going
2510 // to reference is in the string table. We do this since the names we
2511 // add may not only be identical to the names in the DIE.
2512 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2513 if (!useDwarfAccelTables())
2514 return;
2515 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2516 &Die);
2517 }
2519 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2520 if (!useDwarfAccelTables())
2521 return;
2522 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2523 &Die);
2524 }
2526 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2527 if (!useDwarfAccelTables())
2528 return;
2529 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2530 &Die);
2531 }
2533 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2534 if (!useDwarfAccelTables())
2535 return;
2536 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2537 &Die);
2538 }