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.getOrCreateSubprogramDIE(SP);
319 attachLowHighPC(SPCU, *SPDie, FunctionBeginSym, FunctionEndSym);
321 const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
322 MachineLocation Location(RI->getFrameRegister(*Asm->MF));
323 SPCU.addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
325 // Add name to the name table, we do this here because we're guaranteed
326 // to have concrete versions of our DW_TAG_subprogram nodes.
327 addSubprogramNames(SP, *SPDie);
329 return *SPDie;
330 }
332 /// Check whether we should create a DIE for the given Scope, return true
333 /// if we don't create a DIE (the corresponding DIE is null).
334 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
335 if (Scope->isAbstractScope())
336 return false;
338 // We don't create a DIE if there is no Range.
339 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
340 if (Ranges.empty())
341 return true;
343 if (Ranges.size() > 1)
344 return false;
346 // We don't create a DIE if we have a single Range and the end label
347 // is null.
348 SmallVectorImpl<InsnRange>::const_iterator RI = Ranges.begin();
349 MCSymbol *End = getLabelAfterInsn(RI->second);
350 return !End;
351 }
353 static void addSectionLabel(AsmPrinter &Asm, DwarfUnit &U, DIE &D,
354 dwarf::Attribute A, const MCSymbol *L,
355 const MCSymbol *Sec) {
356 if (Asm.MAI->doesDwarfUseRelocationsAcrossSections())
357 U.addSectionLabel(D, A, L);
358 else
359 U.addSectionDelta(D, A, L, Sec);
360 }
362 void DwarfDebug::addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
363 const SmallVectorImpl<InsnRange> &Range) {
364 // Emit offset in .debug_range as a relocatable label. emitDIE will handle
365 // emitting it appropriately.
366 MCSymbol *RangeSym = Asm->GetTempSymbol("debug_ranges", GlobalRangeCount++);
368 // Under fission, ranges are specified by constant offsets relative to the
369 // CU's DW_AT_GNU_ranges_base.
370 if (useSplitDwarf())
371 TheCU.addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
372 DwarfDebugRangeSectionSym);
373 else
374 addSectionLabel(*Asm, TheCU, ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
375 DwarfDebugRangeSectionSym);
377 RangeSpanList List(RangeSym);
378 for (const InsnRange &R : Range) {
379 RangeSpan Span(getLabelBeforeInsn(R.first), getLabelAfterInsn(R.second));
380 List.addRange(std::move(Span));
381 }
383 // Add the range list to the set of ranges to be emitted.
384 TheCU.addRangeList(std::move(List));
385 }
387 void DwarfDebug::attachRangesOrLowHighPC(DwarfCompileUnit &TheCU, DIE &Die,
388 const SmallVectorImpl<InsnRange> &Ranges) {
389 assert(!Ranges.empty());
390 if (Ranges.size() == 1)
391 attachLowHighPC(TheCU, Die, getLabelBeforeInsn(Ranges.front().first),
392 getLabelAfterInsn(Ranges.front().second));
393 else
394 addScopeRangeList(TheCU, Die, Ranges);
395 }
397 // Construct new DW_TAG_lexical_block for this scope and attach
398 // DW_AT_low_pc/DW_AT_high_pc labels.
399 std::unique_ptr<DIE>
400 DwarfDebug::constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
401 LexicalScope *Scope) {
402 if (isLexicalScopeDIENull(Scope))
403 return nullptr;
405 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
406 if (Scope->isAbstractScope())
407 return ScopeDIE;
409 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
411 return ScopeDIE;
412 }
414 // This scope represents inlined body of a function. Construct DIE to
415 // represent this concrete inlined copy of the function.
416 std::unique_ptr<DIE>
417 DwarfDebug::constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
418 LexicalScope *Scope) {
419 assert(Scope->getScopeNode());
420 DIScope DS(Scope->getScopeNode());
421 DISubprogram InlinedSP = getDISubprogram(DS);
422 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
423 // was inlined from another compile unit.
424 DIE *OriginDIE = AbstractSPDies[InlinedSP];
425 assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
427 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
428 TheCU.addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
430 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
432 InlinedSubprogramDIEs.insert(OriginDIE);
434 // Add the call site information to the DIE.
435 DILocation DL(Scope->getInlinedAt());
436 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
437 TheCU.getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
438 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
440 // Add name to the name table, we do this here because we're guaranteed
441 // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
442 addSubprogramNames(InlinedSP, *ScopeDIE);
444 return ScopeDIE;
445 }
447 static std::unique_ptr<DIE> constructVariableDIE(DwarfCompileUnit &TheCU,
448 DbgVariable &DV,
449 const LexicalScope &Scope,
450 DIE *&ObjectPointer) {
451 auto Var = TheCU.constructVariableDIE(DV, Scope.isAbstractScope());
452 if (DV.isObjectPointer())
453 ObjectPointer = Var.get();
454 return Var;
455 }
457 DIE *DwarfDebug::createScopeChildrenDIE(
458 DwarfCompileUnit &TheCU, LexicalScope *Scope,
459 SmallVectorImpl<std::unique_ptr<DIE>> &Children) {
460 DIE *ObjectPointer = nullptr;
462 // Collect arguments for current function.
463 if (LScopes.isCurrentFunctionScope(Scope)) {
464 for (DbgVariable *ArgDV : CurrentFnArguments)
465 if (ArgDV)
466 Children.push_back(
467 constructVariableDIE(TheCU, *ArgDV, *Scope, ObjectPointer));
469 // If this is a variadic function, add an unspecified parameter.
470 DISubprogram SP(Scope->getScopeNode());
471 DIArray FnArgs = SP.getType().getTypeArray();
472 if (FnArgs.getElement(FnArgs.getNumElements() - 1)
473 .isUnspecifiedParameter()) {
474 Children.push_back(
475 make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
476 }
477 }
479 // Collect lexical scope children first.
480 for (DbgVariable *DV : ScopeVariables.lookup(Scope))
481 Children.push_back(constructVariableDIE(TheCU, *DV, *Scope, ObjectPointer));
483 for (LexicalScope *LS : Scope->getChildren())
484 if (std::unique_ptr<DIE> Nested = constructScopeDIE(TheCU, LS))
485 Children.push_back(std::move(Nested));
486 return ObjectPointer;
487 }
489 void DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU,
490 LexicalScope *Scope, DIE &ScopeDIE) {
491 // We create children when the scope DIE is not null.
492 SmallVector<std::unique_ptr<DIE>, 8> Children;
493 if (DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children))
494 TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
496 // Add children
497 for (auto &I : Children)
498 ScopeDIE.addChild(std::move(I));
499 }
501 void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
502 LexicalScope *Scope) {
503 assert(Scope && Scope->getScopeNode());
504 assert(Scope->isAbstractScope());
505 assert(!Scope->getInlinedAt());
507 DISubprogram SP(Scope->getScopeNode());
509 ProcessedSPNodes.insert(SP);
511 DIE *&AbsDef = AbstractSPDies[SP];
512 if (AbsDef)
513 return;
515 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
516 // was inlined from another compile unit.
517 DwarfCompileUnit &SPCU = *SPMap[SP];
518 DIE *ContextDIE;
520 // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
521 // the important distinction that the DIDescriptor is not associated with the
522 // DIE (since the DIDescriptor will be associated with the concrete DIE, if
523 // any). It could be refactored to some common utility function.
524 if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
525 ContextDIE = &SPCU.getUnitDie();
526 SPCU.getOrCreateSubprogramDIE(SPDecl);
527 } else
528 ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
530 // Passing null as the associated DIDescriptor because the abstract definition
531 // shouldn't be found by lookup.
532 AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
533 DIDescriptor());
534 SPCU.applySubprogramAttributes(SP, *AbsDef);
535 SPCU.addGlobalName(SP.getName(), *AbsDef, resolve(SP.getContext()));
537 SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
538 createAndAddScopeChildren(SPCU, Scope, *AbsDef);
539 }
541 DIE &DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
542 LexicalScope *Scope) {
543 assert(Scope && Scope->getScopeNode());
544 assert(!Scope->getInlinedAt());
545 assert(!Scope->isAbstractScope());
546 DISubprogram Sub(Scope->getScopeNode());
548 assert(Sub.isSubprogram());
550 ProcessedSPNodes.insert(Sub);
552 DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub);
554 createAndAddScopeChildren(TheCU, Scope, ScopeDIE);
556 return ScopeDIE;
557 }
559 // Construct a DIE for this scope.
560 std::unique_ptr<DIE> DwarfDebug::constructScopeDIE(DwarfCompileUnit &TheCU,
561 LexicalScope *Scope) {
562 if (!Scope || !Scope->getScopeNode())
563 return nullptr;
565 DIScope DS(Scope->getScopeNode());
567 assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
568 "Only handle inlined subprograms here, use "
569 "constructSubprogramScopeDIE for non-inlined "
570 "subprograms");
572 SmallVector<std::unique_ptr<DIE>, 8> Children;
574 // We try to create the scope DIE first, then the children DIEs. This will
575 // avoid creating un-used children then removing them later when we find out
576 // the scope DIE is null.
577 std::unique_ptr<DIE> ScopeDIE;
578 if (Scope->getParent() && DS.isSubprogram()) {
579 ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
580 if (!ScopeDIE)
581 return nullptr;
582 // We create children when the scope DIE is not null.
583 createScopeChildrenDIE(TheCU, Scope, Children);
584 } else {
585 // Early exit when we know the scope DIE is going to be null.
586 if (isLexicalScopeDIENull(Scope))
587 return nullptr;
589 // We create children here when we know the scope DIE is not going to be
590 // null and the children will be added to the scope DIE.
591 createScopeChildrenDIE(TheCU, Scope, Children);
593 // There is no need to emit empty lexical block DIE.
594 std::pair<ImportedEntityMap::const_iterator,
595 ImportedEntityMap::const_iterator> Range =
596 std::equal_range(ScopesWithImportedEntities.begin(),
597 ScopesWithImportedEntities.end(),
598 std::pair<const MDNode *, const MDNode *>(DS, nullptr),
599 less_first());
600 if (Children.empty() && Range.first == Range.second)
601 return nullptr;
602 ScopeDIE = constructLexicalScopeDIE(TheCU, Scope);
603 assert(ScopeDIE && "Scope DIE should not be null.");
604 for (ImportedEntityMap::const_iterator i = Range.first; i != Range.second;
605 ++i)
606 constructImportedEntityDIE(TheCU, i->second, *ScopeDIE);
607 }
609 // Add children
610 for (auto &I : Children)
611 ScopeDIE->addChild(std::move(I));
613 return ScopeDIE;
614 }
616 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
617 if (!GenerateGnuPubSections)
618 return;
620 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
621 }
623 // Create new DwarfCompileUnit for the given metadata node with tag
624 // DW_TAG_compile_unit.
625 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
626 StringRef FN = DIUnit.getFilename();
627 CompilationDir = DIUnit.getDirectory();
629 auto OwnedUnit = make_unique<DwarfCompileUnit>(
630 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
631 DwarfCompileUnit &NewCU = *OwnedUnit;
632 DIE &Die = NewCU.getUnitDie();
633 InfoHolder.addUnit(std::move(OwnedUnit));
635 // LTO with assembly output shares a single line table amongst multiple CUs.
636 // To avoid the compilation directory being ambiguous, let the line table
637 // explicitly describe the directory of all files, never relying on the
638 // compilation directory.
639 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
640 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
641 NewCU.getUniqueID(), CompilationDir);
643 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
644 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
645 DIUnit.getLanguage());
646 NewCU.addString(Die, dwarf::DW_AT_name, FN);
648 if (!useSplitDwarf()) {
649 NewCU.initStmtList(DwarfLineSectionSym);
651 // If we're using split dwarf the compilation dir is going to be in the
652 // skeleton CU and so we don't need to duplicate it here.
653 if (!CompilationDir.empty())
654 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
656 addGnuPubAttributes(NewCU, Die);
657 }
659 if (DIUnit.isOptimized())
660 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
662 StringRef Flags = DIUnit.getFlags();
663 if (!Flags.empty())
664 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
666 if (unsigned RVer = DIUnit.getRunTimeVersion())
667 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
668 dwarf::DW_FORM_data1, RVer);
670 if (!FirstCU)
671 FirstCU = &NewCU;
673 if (useSplitDwarf()) {
674 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
675 DwarfInfoDWOSectionSym);
676 NewCU.setSkeleton(constructSkeletonCU(NewCU));
677 } else
678 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
679 DwarfInfoSectionSym);
681 CUMap.insert(std::make_pair(DIUnit, &NewCU));
682 CUDieMap.insert(std::make_pair(&Die, &NewCU));
683 return NewCU;
684 }
686 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
687 const MDNode *N) {
688 DIImportedEntity Module(N);
689 assert(Module.Verify());
690 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
691 constructImportedEntityDIE(TheCU, Module, *D);
692 }
694 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
695 const MDNode *N, DIE &Context) {
696 DIImportedEntity Module(N);
697 assert(Module.Verify());
698 return constructImportedEntityDIE(TheCU, Module, Context);
699 }
701 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
702 const DIImportedEntity &Module,
703 DIE &Context) {
704 assert(Module.Verify() &&
705 "Use one of the MDNode * overloads to handle invalid metadata");
706 DIE &IMDie = TheCU.createAndAddDIE(Module.getTag(), Context, Module);
707 DIE *EntityDie;
708 DIDescriptor Entity = resolve(Module.getEntity());
709 if (Entity.isNameSpace())
710 EntityDie = TheCU.getOrCreateNameSpace(DINameSpace(Entity));
711 else if (Entity.isSubprogram())
712 EntityDie = TheCU.getOrCreateSubprogramDIE(DISubprogram(Entity));
713 else if (Entity.isType())
714 EntityDie = TheCU.getOrCreateTypeDIE(DIType(Entity));
715 else
716 EntityDie = TheCU.getDIE(Entity);
717 TheCU.addSourceLine(IMDie, Module.getLineNumber(),
718 Module.getContext().getFilename(),
719 Module.getContext().getDirectory());
720 TheCU.addDIEEntry(IMDie, dwarf::DW_AT_import, *EntityDie);
721 StringRef Name = Module.getName();
722 if (!Name.empty())
723 TheCU.addString(IMDie, dwarf::DW_AT_name, Name);
724 }
726 // Emit all Dwarf sections that should come prior to the content. Create
727 // global DIEs and emit initial debug info sections. This is invoked by
728 // the target AsmPrinter.
729 void DwarfDebug::beginModule() {
730 if (DisableDebugInfoPrinting)
731 return;
733 const Module *M = MMI->getModule();
735 // If module has named metadata anchors then use them, otherwise scan the
736 // module using debug info finder to collect debug info.
737 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
738 if (!CU_Nodes)
739 return;
740 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
742 // Emit initial sections so we can reference labels later.
743 emitSectionLabels();
745 SingleCU = CU_Nodes->getNumOperands() == 1;
747 for (MDNode *N : CU_Nodes->operands()) {
748 DICompileUnit CUNode(N);
749 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
750 DIArray ImportedEntities = CUNode.getImportedEntities();
751 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
752 ScopesWithImportedEntities.push_back(std::make_pair(
753 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
754 ImportedEntities.getElement(i)));
755 std::sort(ScopesWithImportedEntities.begin(),
756 ScopesWithImportedEntities.end(), less_first());
757 DIArray GVs = CUNode.getGlobalVariables();
758 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
759 CU.createGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
760 DIArray SPs = CUNode.getSubprograms();
761 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
762 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
763 DIArray EnumTypes = CUNode.getEnumTypes();
764 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
765 CU.getOrCreateTypeDIE(EnumTypes.getElement(i));
766 DIArray RetainedTypes = CUNode.getRetainedTypes();
767 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
768 DIType Ty(RetainedTypes.getElement(i));
769 // The retained types array by design contains pointers to
770 // MDNodes rather than DIRefs. Unique them here.
771 DIType UniqueTy(resolve(Ty.getRef()));
772 CU.getOrCreateTypeDIE(UniqueTy);
773 }
774 // Emit imported_modules last so that the relevant context is already
775 // available.
776 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
777 constructImportedEntityDIE(CU, ImportedEntities.getElement(i));
778 }
780 // Tell MMI that we have debug info.
781 MMI->setDebugInfoAvailability(true);
783 // Prime section data.
784 SectionMap[Asm->getObjFileLowering().getTextSection()];
785 }
787 void DwarfDebug::finishSubprogramDefinitions() {
788 const Module *M = MMI->getModule();
790 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
791 for (MDNode *N : CU_Nodes->operands()) {
792 DICompileUnit TheCU(N);
793 // Construct subprogram DIE and add variables DIEs.
794 DwarfCompileUnit *SPCU =
795 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
796 DIArray Subprograms = TheCU.getSubprograms();
797 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
798 DISubprogram SP(Subprograms.getElement(i));
799 // Perhaps the subprogram is in another CU (such as due to comdat
800 // folding, etc), in which case ignore it here.
801 if (SPMap[SP] != SPCU)
802 continue;
803 DIE *D = SPCU->getDIE(SP);
804 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
805 if (D)
806 // If this subprogram has an abstract definition, reference that
807 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
808 } else {
809 if (!D)
810 // Lazily construct the subprogram if we didn't see either concrete or
811 // inlined versions during codegen.
812 D = SPCU->getOrCreateSubprogramDIE(SP);
813 // And attach the attributes
814 SPCU->applySubprogramAttributes(SP, *D);
815 SPCU->addGlobalName(SP.getName(), *D, resolve(SP.getContext()));
816 }
817 }
818 }
819 }
822 // Collect info for variables that were optimized out.
823 void DwarfDebug::collectDeadVariables() {
824 const Module *M = MMI->getModule();
826 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
827 for (MDNode *N : CU_Nodes->operands()) {
828 DICompileUnit TheCU(N);
829 // Construct subprogram DIE and add variables DIEs.
830 DwarfCompileUnit *SPCU =
831 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
832 assert(SPCU && "Unable to find Compile Unit!");
833 DIArray Subprograms = TheCU.getSubprograms();
834 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
835 DISubprogram SP(Subprograms.getElement(i));
836 if (ProcessedSPNodes.count(SP) != 0)
837 continue;
838 assert(SP.isSubprogram() &&
839 "CU's subprogram list contains a non-subprogram");
840 assert(SP.isDefinition() &&
841 "CU's subprogram list contains a subprogram declaration");
842 DIArray Variables = SP.getVariables();
843 if (Variables.getNumElements() == 0)
844 continue;
846 DIE *SPDIE = AbstractSPDies.lookup(SP);
847 if (!SPDIE)
848 SPDIE = SPCU->getDIE(SP);
849 assert(SPDIE);
850 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
851 DIVariable DV(Variables.getElement(vi));
852 assert(DV.isVariable());
853 DbgVariable NewVar(DV, nullptr, this);
854 SPDIE->addChild(SPCU->constructVariableDIE(NewVar));
855 }
856 }
857 }
858 }
859 }
861 void DwarfDebug::finalizeModuleInfo() {
862 finishSubprogramDefinitions();
864 // Collect info for variables that were optimized out.
865 collectDeadVariables();
867 // Handle anything that needs to be done on a per-unit basis after
868 // all other generation.
869 for (const auto &TheU : getUnits()) {
870 // Emit DW_AT_containing_type attribute to connect types with their
871 // vtable holding type.
872 TheU->constructContainingTypeDIEs();
874 // Add CU specific attributes if we need to add any.
875 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
876 // If we're splitting the dwarf out now that we've got the entire
877 // CU then add the dwo id to it.
878 DwarfCompileUnit *SkCU =
879 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
880 if (useSplitDwarf()) {
881 // Emit a unique identifier for this CU.
882 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
883 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
884 dwarf::DW_FORM_data8, ID);
885 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
886 dwarf::DW_FORM_data8, ID);
888 // We don't keep track of which addresses are used in which CU so this
889 // is a bit pessimistic under LTO.
890 if (!AddrPool.isEmpty())
891 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
892 dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
893 DwarfAddrSectionSym);
894 if (!TheU->getRangeLists().empty())
895 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
896 dwarf::DW_AT_GNU_ranges_base,
897 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
898 }
900 // If we have code split among multiple sections or non-contiguous
901 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
902 // remain in the .o file, otherwise add a DW_AT_low_pc.
903 // FIXME: We should use ranges allow reordering of code ala
904 // .subsections_via_symbols in mach-o. This would mean turning on
905 // ranges for all subprogram DIEs for mach-o.
906 DwarfCompileUnit &U =
907 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
908 unsigned NumRanges = TheU->getRanges().size();
909 if (NumRanges) {
910 if (NumRanges > 1) {
911 addSectionLabel(*Asm, U, U.getUnitDie(), dwarf::DW_AT_ranges,
912 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
913 DwarfDebugRangeSectionSym);
915 // A DW_AT_low_pc attribute may also be specified in combination with
916 // DW_AT_ranges to specify the default base address for use in
917 // location lists (see Section 2.6.2) and range lists (see Section
918 // 2.17.3).
919 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
920 0);
921 } else {
922 RangeSpan &Range = TheU->getRanges().back();
923 U.addLocalLabelAddress(U.getUnitDie(), dwarf::DW_AT_low_pc,
924 Range.getStart());
925 U.addLabelDelta(U.getUnitDie(), dwarf::DW_AT_high_pc, Range.getEnd(),
926 Range.getStart());
927 }
928 }
929 }
930 }
932 // Compute DIE offsets and sizes.
933 InfoHolder.computeSizeAndOffsets();
934 if (useSplitDwarf())
935 SkeletonHolder.computeSizeAndOffsets();
936 }
938 void DwarfDebug::endSections() {
939 // Filter labels by section.
940 for (const SymbolCU &SCU : ArangeLabels) {
941 if (SCU.Sym->isInSection()) {
942 // Make a note of this symbol and it's section.
943 const MCSection *Section = &SCU.Sym->getSection();
944 if (!Section->getKind().isMetadata())
945 SectionMap[Section].push_back(SCU);
946 } else {
947 // Some symbols (e.g. common/bss on mach-o) can have no section but still
948 // appear in the output. This sucks as we rely on sections to build
949 // arange spans. We can do it without, but it's icky.
950 SectionMap[nullptr].push_back(SCU);
951 }
952 }
954 // Build a list of sections used.
955 std::vector<const MCSection *> Sections;
956 for (const auto &it : SectionMap) {
957 const MCSection *Section = it.first;
958 Sections.push_back(Section);
959 }
961 // Sort the sections into order.
962 // This is only done to ensure consistent output order across different runs.
963 std::sort(Sections.begin(), Sections.end(), SectionSort);
965 // Add terminating symbols for each section.
966 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
967 const MCSection *Section = Sections[ID];
968 MCSymbol *Sym = nullptr;
970 if (Section) {
971 // We can't call MCSection::getLabelEndName, as it's only safe to do so
972 // if we know the section name up-front. For user-created sections, the
973 // resulting label may not be valid to use as a label. (section names can
974 // use a greater set of characters on some systems)
975 Sym = Asm->GetTempSymbol("debug_end", ID);
976 Asm->OutStreamer.SwitchSection(Section);
977 Asm->OutStreamer.EmitLabel(Sym);
978 }
980 // Insert a final terminator.
981 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
982 }
983 }
985 // Emit all Dwarf sections that should come after the content.
986 void DwarfDebug::endModule() {
987 assert(CurFn == nullptr);
988 assert(CurMI == nullptr);
990 if (!FirstCU)
991 return;
993 // End any existing sections.
994 // TODO: Does this need to happen?
995 endSections();
997 // Finalize the debug info for the module.
998 finalizeModuleInfo();
1000 emitDebugStr();
1002 // Emit all the DIEs into a debug info section.
1003 emitDebugInfo();
1005 // Corresponding abbreviations into a abbrev section.
1006 emitAbbreviations();
1008 // Emit info into a debug aranges section.
1009 if (GenerateARangeSection)
1010 emitDebugARanges();
1012 // Emit info into a debug ranges section.
1013 emitDebugRanges();
1015 if (useSplitDwarf()) {
1016 emitDebugStrDWO();
1017 emitDebugInfoDWO();
1018 emitDebugAbbrevDWO();
1019 emitDebugLineDWO();
1020 // Emit DWO addresses.
1021 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
1022 emitDebugLocDWO();
1023 } else
1024 // Emit info into a debug loc section.
1025 emitDebugLoc();
1027 // Emit info into the dwarf accelerator table sections.
1028 if (useDwarfAccelTables()) {
1029 emitAccelNames();
1030 emitAccelObjC();
1031 emitAccelNamespaces();
1032 emitAccelTypes();
1033 }
1035 // Emit the pubnames and pubtypes sections if requested.
1036 if (HasDwarfPubSections) {
1037 emitDebugPubNames(GenerateGnuPubSections);
1038 emitDebugPubTypes(GenerateGnuPubSections);
1039 }
1041 // clean up.
1042 SPMap.clear();
1043 AbstractVariables.clear();
1045 // Reset these for the next Module if we have one.
1046 FirstCU = nullptr;
1047 }
1049 // Find abstract variable, if any, associated with Var.
1050 DbgVariable *DwarfDebug::findAbstractVariable(DIVariable &DV,
1051 DebugLoc ScopeLoc) {
1052 return findAbstractVariable(DV, ScopeLoc.getScope(DV->getContext()));
1053 }
1055 DbgVariable *DwarfDebug::findAbstractVariable(DIVariable &DV,
1056 const MDNode *ScopeNode) {
1057 LLVMContext &Ctx = DV->getContext();
1058 // More then one inlined variable corresponds to one abstract variable.
1059 DIVariable Var = cleanseInlinedVariable(DV, Ctx);
1060 auto I = AbstractVariables.find(Var);
1061 if (I != AbstractVariables.end())
1062 return I->second.get();
1064 LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode);
1065 if (!Scope)
1066 return nullptr;
1068 auto AbsDbgVariable = make_unique<DbgVariable>(Var, nullptr, this);
1069 addScopeVariable(Scope, AbsDbgVariable.get());
1070 return (AbstractVariables[Var] = std::move(AbsDbgVariable)).get();
1071 }
1073 // If Var is a current function argument then add it to CurrentFnArguments list.
1074 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
1075 if (!LScopes.isCurrentFunctionScope(Scope))
1076 return false;
1077 DIVariable DV = Var->getVariable();
1078 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
1079 return false;
1080 unsigned ArgNo = DV.getArgNumber();
1081 if (ArgNo == 0)
1082 return false;
1084 size_t Size = CurrentFnArguments.size();
1085 if (Size == 0)
1086 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
1087 // llvm::Function argument size is not good indicator of how many
1088 // arguments does the function have at source level.
1089 if (ArgNo > Size)
1090 CurrentFnArguments.resize(ArgNo * 2);
1091 CurrentFnArguments[ArgNo - 1] = Var;
1092 return true;
1093 }
1095 // Collect variable information from side table maintained by MMI.
1096 void DwarfDebug::collectVariableInfoFromMMITable(
1097 SmallPtrSet<const MDNode *, 16> &Processed) {
1098 for (const auto &VI : MMI->getVariableDbgInfo()) {
1099 if (!VI.Var)
1100 continue;
1101 Processed.insert(VI.Var);
1102 DIVariable DV(VI.Var);
1103 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
1105 // If variable scope is not found then skip this variable.
1106 if (!Scope)
1107 continue;
1109 DbgVariable *AbsDbgVariable = findAbstractVariable(DV, VI.Loc);
1110 DbgVariable *RegVar = new DbgVariable(DV, AbsDbgVariable, this);
1111 RegVar->setFrameIndex(VI.Slot);
1112 if (!addCurrentFnArgument(RegVar, Scope))
1113 addScopeVariable(Scope, RegVar);
1114 }
1115 }
1117 // Get .debug_loc entry for the instruction range starting at MI.
1118 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
1119 const MDNode *Var = MI->getDebugVariable();
1121 assert(MI->getNumOperands() == 3);
1122 if (MI->getOperand(0).isReg()) {
1123 MachineLocation MLoc;
1124 // If the second operand is an immediate, this is a
1125 // register-indirect address.
1126 if (!MI->getOperand(1).isImm())
1127 MLoc.set(MI->getOperand(0).getReg());
1128 else
1129 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
1130 return DebugLocEntry::Value(Var, MLoc);
1131 }
1132 if (MI->getOperand(0).isImm())
1133 return DebugLocEntry::Value(Var, MI->getOperand(0).getImm());
1134 if (MI->getOperand(0).isFPImm())
1135 return DebugLocEntry::Value(Var, MI->getOperand(0).getFPImm());
1136 if (MI->getOperand(0).isCImm())
1137 return DebugLocEntry::Value(Var, MI->getOperand(0).getCImm());
1139 llvm_unreachable("Unexpected 3 operand DBG_VALUE instruction!");
1140 }
1142 // Find variables for each lexical scope.
1143 void
1144 DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
1145 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1146 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1148 // Grab the variable info that was squirreled away in the MMI side-table.
1149 collectVariableInfoFromMMITable(Processed);
1151 for (const auto &I : DbgValues) {
1152 DIVariable DV(I.first);
1153 if (Processed.count(DV))
1154 continue;
1156 // Instruction ranges, specifying where DV is accessible.
1157 const auto &Ranges = I.second;
1158 if (Ranges.empty())
1159 continue;
1161 LexicalScope *Scope = nullptr;
1162 if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
1163 DISubprogram(DV.getContext()).describes(CurFn->getFunction()))
1164 Scope = LScopes.getCurrentFunctionScope();
1165 else if (MDNode *IA = DV.getInlinedAt()) {
1166 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1167 Scope = LScopes.findInlinedScope(DebugLoc::get(
1168 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1169 } else
1170 Scope = LScopes.findLexicalScope(DV.getContext());
1171 // If variable scope is not found then skip this variable.
1172 if (!Scope)
1173 continue;
1175 Processed.insert(DV);
1176 const MachineInstr *MInsn = Ranges.front().first;
1177 assert(MInsn->isDebugValue() && "History must begin with debug value");
1178 DbgVariable *AbsVar = findAbstractVariable(DV, MInsn->getDebugLoc());
1179 DbgVariable *RegVar = new DbgVariable(MInsn, AbsVar, this);
1180 if (!addCurrentFnArgument(RegVar, Scope))
1181 addScopeVariable(Scope, RegVar);
1183 // Check if the first DBG_VALUE is valid for the rest of the function.
1184 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1185 continue;
1187 // Handle multiple DBG_VALUE instructions describing one variable.
1188 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1190 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1191 DebugLocList &LocList = DotDebugLocEntries.back();
1192 LocList.Label =
1193 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1194 SmallVector<DebugLocEntry, 4> &DebugLoc = LocList.List;
1195 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1196 const MachineInstr *Begin = I->first;
1197 const MachineInstr *End = I->second;
1198 assert(Begin->isDebugValue() && "Invalid History entry");
1200 // Check if a variable is unaccessible in this range.
1201 if (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
1202 !Begin->getOperand(0).getReg())
1203 continue;
1205 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
1206 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
1208 const MCSymbol *EndLabel;
1209 if (End != nullptr)
1210 EndLabel = getLabelAfterInsn(End);
1211 else if (std::next(I) == Ranges.end())
1212 EndLabel = FunctionEndSym;
1213 else
1214 EndLabel = getLabelBeforeInsn(std::next(I)->first);
1215 assert(EndLabel && "Forgot label after instruction ending a range!");
1217 DEBUG(dbgs() << "DotDebugLoc Pair:\n"
1218 << "\t" << *Begin << "\t" << *End << "\n");
1219 DebugLocEntry Loc(StartLabel, EndLabel, getDebugLocValue(Begin), TheCU);
1220 if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc))
1221 DebugLoc.push_back(std::move(Loc));
1222 }
1223 }
1225 // Collect info for variables that were optimized out.
1226 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1227 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1228 DIVariable DV(Variables.getElement(i));
1229 assert(DV.isVariable());
1230 if (!Processed.insert(DV))
1231 continue;
1232 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext()))
1233 addScopeVariable(
1234 Scope,
1235 new DbgVariable(DV, findAbstractVariable(DV, Scope->getScopeNode()),
1236 this));
1237 }
1238 }
1240 // Return Label preceding the instruction.
1241 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1242 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1243 assert(Label && "Didn't insert label before instruction");
1244 return Label;
1245 }
1247 // Return Label immediately following the instruction.
1248 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1249 return LabelsAfterInsn.lookup(MI);
1250 }
1252 // Process beginning of an instruction.
1253 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1254 assert(CurMI == nullptr);
1255 CurMI = MI;
1256 // Check if source location changes, but ignore DBG_VALUE locations.
1257 if (!MI->isDebugValue()) {
1258 DebugLoc DL = MI->getDebugLoc();
1259 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1260 unsigned Flags = 0;
1261 PrevInstLoc = DL;
1262 if (DL == PrologEndLoc) {
1263 Flags |= DWARF2_FLAG_PROLOGUE_END;
1264 PrologEndLoc = DebugLoc();
1265 }
1266 if (PrologEndLoc.isUnknown())
1267 Flags |= DWARF2_FLAG_IS_STMT;
1269 if (!DL.isUnknown()) {
1270 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1271 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1272 } else
1273 recordSourceLine(0, 0, nullptr, 0);
1274 }
1275 }
1277 // Insert labels where requested.
1278 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1279 LabelsBeforeInsn.find(MI);
1281 // No label needed.
1282 if (I == LabelsBeforeInsn.end())
1283 return;
1285 // Label already assigned.
1286 if (I->second)
1287 return;
1289 if (!PrevLabel) {
1290 PrevLabel = MMI->getContext().CreateTempSymbol();
1291 Asm->OutStreamer.EmitLabel(PrevLabel);
1292 }
1293 I->second = PrevLabel;
1294 }
1296 // Process end of an instruction.
1297 void DwarfDebug::endInstruction() {
1298 assert(CurMI != nullptr);
1299 // Don't create a new label after DBG_VALUE instructions.
1300 // They don't generate code.
1301 if (!CurMI->isDebugValue())
1302 PrevLabel = nullptr;
1304 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1305 LabelsAfterInsn.find(CurMI);
1306 CurMI = nullptr;
1308 // No label needed.
1309 if (I == LabelsAfterInsn.end())
1310 return;
1312 // Label already assigned.
1313 if (I->second)
1314 return;
1316 // We need a label after this instruction.
1317 if (!PrevLabel) {
1318 PrevLabel = MMI->getContext().CreateTempSymbol();
1319 Asm->OutStreamer.EmitLabel(PrevLabel);
1320 }
1321 I->second = PrevLabel;
1322 }
1324 // Each LexicalScope has first instruction and last instruction to mark
1325 // beginning and end of a scope respectively. Create an inverse map that list
1326 // scopes starts (and ends) with an instruction. One instruction may start (or
1327 // end) multiple scopes. Ignore scopes that are not reachable.
1328 void DwarfDebug::identifyScopeMarkers() {
1329 SmallVector<LexicalScope *, 4> WorkList;
1330 WorkList.push_back(LScopes.getCurrentFunctionScope());
1331 while (!WorkList.empty()) {
1332 LexicalScope *S = WorkList.pop_back_val();
1334 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1335 if (!Children.empty())
1336 WorkList.append(Children.begin(), Children.end());
1338 if (S->isAbstractScope())
1339 continue;
1341 for (const InsnRange &R : S->getRanges()) {
1342 assert(R.first && "InsnRange does not have first instruction!");
1343 assert(R.second && "InsnRange does not have second instruction!");
1344 requestLabelBeforeInsn(R.first);
1345 requestLabelAfterInsn(R.second);
1346 }
1347 }
1348 }
1350 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1351 // First known non-DBG_VALUE and non-frame setup location marks
1352 // the beginning of the function body.
1353 for (const auto &MBB : *MF)
1354 for (const auto &MI : MBB)
1355 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1356 !MI.getDebugLoc().isUnknown())
1357 return MI.getDebugLoc();
1358 return DebugLoc();
1359 }
1361 // Gather pre-function debug information. Assumes being called immediately
1362 // after the function entry point has been emitted.
1363 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1364 CurFn = MF;
1366 // If there's no debug info for the function we're not going to do anything.
1367 if (!MMI->hasDebugInfo())
1368 return;
1370 // Grab the lexical scopes for the function, if we don't have any of those
1371 // then we're not going to be able to do anything.
1372 LScopes.initialize(*MF);
1373 if (LScopes.empty())
1374 return;
1376 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1378 // Make sure that each lexical scope will have a begin/end label.
1379 identifyScopeMarkers();
1381 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1382 // belongs to so that we add to the correct per-cu line table in the
1383 // non-asm case.
1384 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1385 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1386 assert(TheCU && "Unable to find compile unit!");
1387 if (Asm->OutStreamer.hasRawTextSupport())
1388 // Use a single line table if we are generating assembly.
1389 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1390 else
1391 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1393 // Emit a label for the function so that we have a beginning address.
1394 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1395 // Assumes in correct section after the entry point.
1396 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1398 // Calculate history for local variables.
1399 calculateDbgValueHistory(MF, Asm->TM.getRegisterInfo(), DbgValues);
1401 // Request labels for the full history.
1402 for (const auto &I : DbgValues) {
1403 const auto &Ranges = I.second;
1404 if (Ranges.empty())
1405 continue;
1407 // The first mention of a function argument gets the FunctionBeginSym
1408 // label, so arguments are visible when breaking at function entry.
1409 DIVariable DV(I.first);
1410 if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
1411 getDISubprogram(DV.getContext()).describes(MF->getFunction()))
1412 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1414 for (const auto &Range : Ranges) {
1415 requestLabelBeforeInsn(Range.first);
1416 if (Range.second)
1417 requestLabelAfterInsn(Range.second);
1418 }
1419 }
1421 PrevInstLoc = DebugLoc();
1422 PrevLabel = FunctionBeginSym;
1424 // Record beginning of function.
1425 PrologEndLoc = findPrologueEndLoc(MF);
1426 if (!PrologEndLoc.isUnknown()) {
1427 DebugLoc FnStartDL =
1428 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1429 recordSourceLine(
1430 FnStartDL.getLine(), FnStartDL.getCol(),
1431 FnStartDL.getScope(MF->getFunction()->getContext()),
1432 // We'd like to list the prologue as "not statements" but GDB behaves
1433 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1434 DWARF2_FLAG_IS_STMT);
1435 }
1436 }
1438 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1439 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1440 DIVariable DV = Var->getVariable();
1441 // Variables with positive arg numbers are parameters.
1442 if (unsigned ArgNum = DV.getArgNumber()) {
1443 // Keep all parameters in order at the start of the variable list to ensure
1444 // function types are correct (no out-of-order parameters)
1445 //
1446 // This could be improved by only doing it for optimized builds (unoptimized
1447 // builds have the right order to begin with), searching from the back (this
1448 // would catch the unoptimized case quickly), or doing a binary search
1449 // rather than linear search.
1450 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1451 while (I != Vars.end()) {
1452 unsigned CurNum = (*I)->getVariable().getArgNumber();
1453 // A local (non-parameter) variable has been found, insert immediately
1454 // before it.
1455 if (CurNum == 0)
1456 break;
1457 // A later indexed parameter has been found, insert immediately before it.
1458 if (CurNum > ArgNum)
1459 break;
1460 ++I;
1461 }
1462 Vars.insert(I, Var);
1463 return;
1464 }
1466 Vars.push_back(Var);
1467 }
1469 // Gather and emit post-function debug information.
1470 void DwarfDebug::endFunction(const MachineFunction *MF) {
1471 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1472 // though the beginFunction may not be called at all.
1473 // We should handle both cases.
1474 if (!CurFn)
1475 CurFn = MF;
1476 else
1477 assert(CurFn == MF);
1478 assert(CurFn != nullptr);
1480 if (!MMI->hasDebugInfo() || LScopes.empty()) {
1481 // If we don't have a lexical scope for this function then there will
1482 // be a hole in the range information. Keep note of this by setting the
1483 // previously used section to nullptr.
1484 PrevSection = nullptr;
1485 PrevCU = nullptr;
1486 CurFn = nullptr;
1487 return;
1488 }
1490 // Define end label for subprogram.
1491 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1492 // Assumes in correct section after the entry point.
1493 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1495 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1496 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1498 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1499 collectVariableInfo(ProcessedVars);
1501 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1502 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1504 // Construct abstract scopes.
1505 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1506 DISubprogram SP(AScope->getScopeNode());
1507 if (!SP.isSubprogram())
1508 continue;
1509 // Collect info for variables that were optimized out.
1510 DIArray Variables = SP.getVariables();
1511 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1512 DIVariable DV(Variables.getElement(i));
1513 assert(DV && DV.isVariable());
1514 if (!ProcessedVars.insert(DV))
1515 continue;
1516 findAbstractVariable(DV, DV.getContext());
1517 }
1518 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1519 }
1521 DIE &CurFnDIE = constructSubprogramScopeDIE(TheCU, FnScope);
1522 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
1523 TheCU.addFlag(CurFnDIE, dwarf::DW_AT_APPLE_omit_frame_ptr);
1525 // Add the range of this function to the list of ranges for the CU.
1526 RangeSpan Span(FunctionBeginSym, FunctionEndSym);
1527 TheCU.addRange(std::move(Span));
1528 PrevSection = Asm->getCurrentSection();
1529 PrevCU = &TheCU;
1531 // Clear debug info
1532 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1533 // DbgVariables except those that are also in AbstractVariables (since they
1534 // can be used cross-function)
1535 for (const auto &I : ScopeVariables)
1536 for (const auto *Var : I.second)
1537 if (!AbstractVariables.count(Var->getVariable()) || Var->getAbstractVariable())
1538 delete Var;
1539 ScopeVariables.clear();
1540 DeleteContainerPointers(CurrentFnArguments);
1541 DbgValues.clear();
1542 LabelsBeforeInsn.clear();
1543 LabelsAfterInsn.clear();
1544 PrevLabel = nullptr;
1545 CurFn = nullptr;
1546 }
1548 // Register a source line with debug info. Returns the unique label that was
1549 // emitted and which provides correspondence to the source line list.
1550 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1551 unsigned Flags) {
1552 StringRef Fn;
1553 StringRef Dir;
1554 unsigned Src = 1;
1555 unsigned Discriminator = 0;
1556 if (DIScope Scope = DIScope(S)) {
1557 assert(Scope.isScope());
1558 Fn = Scope.getFilename();
1559 Dir = Scope.getDirectory();
1560 if (Scope.isLexicalBlock())
1561 Discriminator = DILexicalBlock(S).getDiscriminator();
1563 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1564 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1565 .getOrCreateSourceID(Fn, Dir);
1566 }
1567 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1568 Discriminator, Fn);
1569 }
1571 //===----------------------------------------------------------------------===//
1572 // Emit Methods
1573 //===----------------------------------------------------------------------===//
1575 // Emit initial Dwarf sections with a label at the start of each one.
1576 void DwarfDebug::emitSectionLabels() {
1577 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1579 // Dwarf sections base addresses.
1580 DwarfInfoSectionSym =
1581 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1582 if (useSplitDwarf())
1583 DwarfInfoDWOSectionSym =
1584 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1585 DwarfAbbrevSectionSym =
1586 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1587 if (useSplitDwarf())
1588 DwarfAbbrevDWOSectionSym = emitSectionSym(
1589 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1590 if (GenerateARangeSection)
1591 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1593 DwarfLineSectionSym =
1594 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1595 if (GenerateGnuPubSections) {
1596 DwarfGnuPubNamesSectionSym =
1597 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1598 DwarfGnuPubTypesSectionSym =
1599 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1600 } else if (HasDwarfPubSections) {
1601 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1602 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1603 }
1605 DwarfStrSectionSym =
1606 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1607 if (useSplitDwarf()) {
1608 DwarfStrDWOSectionSym =
1609 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1610 DwarfAddrSectionSym =
1611 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1612 DwarfDebugLocSectionSym =
1613 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1614 } else
1615 DwarfDebugLocSectionSym =
1616 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1617 DwarfDebugRangeSectionSym =
1618 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1619 }
1621 // Recursively emits a debug information entry.
1622 void DwarfDebug::emitDIE(DIE &Die) {
1623 // Get the abbreviation for this DIE.
1624 const DIEAbbrev &Abbrev = Die.getAbbrev();
1626 // Emit the code (index) for the abbreviation.
1627 if (Asm->isVerbose())
1628 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1629 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1630 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1631 dwarf::TagString(Abbrev.getTag()));
1632 Asm->EmitULEB128(Abbrev.getNumber());
1634 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1635 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1637 // Emit the DIE attribute values.
1638 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1639 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1640 dwarf::Form Form = AbbrevData[i].getForm();
1641 assert(Form && "Too many attributes for DIE (check abbreviation)");
1643 if (Asm->isVerbose()) {
1644 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1645 if (Attr == dwarf::DW_AT_accessibility)
1646 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1647 cast<DIEInteger>(Values[i])->getValue()));
1648 }
1650 // Emit an attribute using the defined form.
1651 Values[i]->EmitValue(Asm, Form);
1652 }
1654 // Emit the DIE children if any.
1655 if (Abbrev.hasChildren()) {
1656 for (auto &Child : Die.getChildren())
1657 emitDIE(*Child);
1659 Asm->OutStreamer.AddComment("End Of Children Mark");
1660 Asm->EmitInt8(0);
1661 }
1662 }
1664 // Emit the debug info section.
1665 void DwarfDebug::emitDebugInfo() {
1666 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1668 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1669 }
1671 // Emit the abbreviation section.
1672 void DwarfDebug::emitAbbreviations() {
1673 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1675 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1676 }
1678 // Emit the last address of the section and the end of the line matrix.
1679 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1680 // Define last address of section.
1681 Asm->OutStreamer.AddComment("Extended Op");
1682 Asm->EmitInt8(0);
1684 Asm->OutStreamer.AddComment("Op size");
1685 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1686 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1687 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1689 Asm->OutStreamer.AddComment("Section end label");
1691 Asm->OutStreamer.EmitSymbolValue(
1692 Asm->GetTempSymbol("section_end", SectionEnd),
1693 Asm->getDataLayout().getPointerSize());
1695 // Mark end of matrix.
1696 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1697 Asm->EmitInt8(0);
1698 Asm->EmitInt8(1);
1699 Asm->EmitInt8(1);
1700 }
1702 // Emit visible names into a hashed accelerator table section.
1703 void DwarfDebug::emitAccelNames() {
1704 AccelNames.FinalizeTable(Asm, "Names");
1705 Asm->OutStreamer.SwitchSection(
1706 Asm->getObjFileLowering().getDwarfAccelNamesSection());
1707 MCSymbol *SectionBegin = Asm->GetTempSymbol("names_begin");
1708 Asm->OutStreamer.EmitLabel(SectionBegin);
1710 // Emit the full data.
1711 AccelNames.Emit(Asm, SectionBegin, &InfoHolder);
1712 }
1714 // Emit objective C classes and categories into a hashed accelerator table
1715 // section.
1716 void DwarfDebug::emitAccelObjC() {
1717 AccelObjC.FinalizeTable(Asm, "ObjC");
1718 Asm->OutStreamer.SwitchSection(
1719 Asm->getObjFileLowering().getDwarfAccelObjCSection());
1720 MCSymbol *SectionBegin = Asm->GetTempSymbol("objc_begin");
1721 Asm->OutStreamer.EmitLabel(SectionBegin);
1723 // Emit the full data.
1724 AccelObjC.Emit(Asm, SectionBegin, &InfoHolder);
1725 }
1727 // Emit namespace dies into a hashed accelerator table.
1728 void DwarfDebug::emitAccelNamespaces() {
1729 AccelNamespace.FinalizeTable(Asm, "namespac");
1730 Asm->OutStreamer.SwitchSection(
1731 Asm->getObjFileLowering().getDwarfAccelNamespaceSection());
1732 MCSymbol *SectionBegin = Asm->GetTempSymbol("namespac_begin");
1733 Asm->OutStreamer.EmitLabel(SectionBegin);
1735 // Emit the full data.
1736 AccelNamespace.Emit(Asm, SectionBegin, &InfoHolder);
1737 }
1739 // Emit type dies into a hashed accelerator table.
1740 void DwarfDebug::emitAccelTypes() {
1742 AccelTypes.FinalizeTable(Asm, "types");
1743 Asm->OutStreamer.SwitchSection(
1744 Asm->getObjFileLowering().getDwarfAccelTypesSection());
1745 MCSymbol *SectionBegin = Asm->GetTempSymbol("types_begin");
1746 Asm->OutStreamer.EmitLabel(SectionBegin);
1748 // Emit the full data.
1749 AccelTypes.Emit(Asm, SectionBegin, &InfoHolder);
1750 }
1752 // Public name handling.
1753 // The format for the various pubnames:
1754 //
1755 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1756 // for the DIE that is named.
1757 //
1758 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1759 // into the CU and the index value is computed according to the type of value
1760 // for the DIE that is named.
1761 //
1762 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1763 // it's the offset within the debug_info/debug_types dwo section, however, the
1764 // reference in the pubname header doesn't change.
1766 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1767 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1768 const DIE *Die) {
1769 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1771 // We could have a specification DIE that has our most of our knowledge,
1772 // look for that now.
1773 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1774 if (SpecVal) {
1775 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1776 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1777 Linkage = dwarf::GIEL_EXTERNAL;
1778 } else if (Die->findAttribute(dwarf::DW_AT_external))
1779 Linkage = dwarf::GIEL_EXTERNAL;
1781 switch (Die->getTag()) {
1782 case dwarf::DW_TAG_class_type:
1783 case dwarf::DW_TAG_structure_type:
1784 case dwarf::DW_TAG_union_type:
1785 case dwarf::DW_TAG_enumeration_type:
1786 return dwarf::PubIndexEntryDescriptor(
1787 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1788 ? dwarf::GIEL_STATIC
1789 : dwarf::GIEL_EXTERNAL);
1790 case dwarf::DW_TAG_typedef:
1791 case dwarf::DW_TAG_base_type:
1792 case dwarf::DW_TAG_subrange_type:
1793 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1794 case dwarf::DW_TAG_namespace:
1795 return dwarf::GIEK_TYPE;
1796 case dwarf::DW_TAG_subprogram:
1797 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1798 case dwarf::DW_TAG_constant:
1799 case dwarf::DW_TAG_variable:
1800 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1801 case dwarf::DW_TAG_enumerator:
1802 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1803 dwarf::GIEL_STATIC);
1804 default:
1805 return dwarf::GIEK_NONE;
1806 }
1807 }
1809 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1810 ///
1811 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1812 const MCSection *PSec =
1813 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1814 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1816 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1817 }
1819 void DwarfDebug::emitDebugPubSection(
1820 bool GnuStyle, const MCSection *PSec, StringRef Name,
1821 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1822 for (const auto &NU : CUMap) {
1823 DwarfCompileUnit *TheU = NU.second;
1825 const auto &Globals = (TheU->*Accessor)();
1827 if (Globals.empty())
1828 continue;
1830 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1831 TheU = Skeleton;
1832 unsigned ID = TheU->getUniqueID();
1834 // Start the dwarf pubnames section.
1835 Asm->OutStreamer.SwitchSection(PSec);
1837 // Emit the header.
1838 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1839 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1840 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1841 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1843 Asm->OutStreamer.EmitLabel(BeginLabel);
1845 Asm->OutStreamer.AddComment("DWARF Version");
1846 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1848 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1849 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1851 Asm->OutStreamer.AddComment("Compilation Unit Length");
1852 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1854 // Emit the pubnames for this compilation unit.
1855 for (const auto &GI : Globals) {
1856 const char *Name = GI.getKeyData();
1857 const DIE *Entity = GI.second;
1859 Asm->OutStreamer.AddComment("DIE offset");
1860 Asm->EmitInt32(Entity->getOffset());
1862 if (GnuStyle) {
1863 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1864 Asm->OutStreamer.AddComment(
1865 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1866 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1867 Asm->EmitInt8(Desc.toBits());
1868 }
1870 Asm->OutStreamer.AddComment("External Name");
1871 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1872 }
1874 Asm->OutStreamer.AddComment("End Mark");
1875 Asm->EmitInt32(0);
1876 Asm->OutStreamer.EmitLabel(EndLabel);
1877 }
1878 }
1880 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1881 const MCSection *PSec =
1882 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1883 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1885 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1886 }
1888 // Emit visible names into a debug str section.
1889 void DwarfDebug::emitDebugStr() {
1890 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1891 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1892 }
1894 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1895 const DebugLocEntry &Entry) {
1896 assert(Entry.getValues().size() == 1 &&
1897 "multi-value entries are not supported yet.");
1898 const DebugLocEntry::Value Value = Entry.getValues()[0];
1899 DIVariable DV(Value.getVariable());
1900 if (Value.isInt()) {
1901 DIBasicType BTy(resolve(DV.getType()));
1902 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1903 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1904 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1905 Streamer.EmitSLEB128(Value.getInt());
1906 } else {
1907 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1908 Streamer.EmitULEB128(Value.getInt());
1909 }
1910 } else if (Value.isLocation()) {
1911 MachineLocation Loc = Value.getLoc();
1912 if (!DV.hasComplexAddress())
1913 // Regular entry.
1914 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1915 else {
1916 // Complex address entry.
1917 unsigned N = DV.getNumAddrElements();
1918 unsigned i = 0;
1919 if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
1920 if (Loc.getOffset()) {
1921 i = 2;
1922 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1923 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1924 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1925 Streamer.EmitSLEB128(DV.getAddrElement(1));
1926 } else {
1927 // If first address element is OpPlus then emit
1928 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1929 MachineLocation TLoc(Loc.getReg(), DV.getAddrElement(1));
1930 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1931 i = 2;
1932 }
1933 } else {
1934 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1935 }
1937 // Emit remaining complex address elements.
1938 for (; i < N; ++i) {
1939 uint64_t Element = DV.getAddrElement(i);
1940 if (Element == DIBuilder::OpPlus) {
1941 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1942 Streamer.EmitULEB128(DV.getAddrElement(++i));
1943 } else if (Element == DIBuilder::OpDeref) {
1944 if (!Loc.isReg())
1945 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1946 } else
1947 llvm_unreachable("unknown Opcode found in complex address");
1948 }
1949 }
1950 }
1951 // else ... ignore constant fp. There is not any good way to
1952 // to represent them here in dwarf.
1953 // FIXME: ^
1954 }
1956 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1957 Asm->OutStreamer.AddComment("Loc expr size");
1958 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1959 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1960 Asm->EmitLabelDifference(end, begin, 2);
1961 Asm->OutStreamer.EmitLabel(begin);
1962 // Emit the entry.
1963 APByteStreamer Streamer(*Asm);
1964 emitDebugLocEntry(Streamer, Entry);
1965 // Close the range.
1966 Asm->OutStreamer.EmitLabel(end);
1967 }
1969 // Emit locations into the debug loc section.
1970 void DwarfDebug::emitDebugLoc() {
1971 // Start the dwarf loc section.
1972 Asm->OutStreamer.SwitchSection(
1973 Asm->getObjFileLowering().getDwarfLocSection());
1974 unsigned char Size = Asm->getDataLayout().getPointerSize();
1975 for (const auto &DebugLoc : DotDebugLocEntries) {
1976 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1977 for (const auto &Entry : DebugLoc.List) {
1978 // Set up the range. This range is relative to the entry point of the
1979 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1980 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1981 const DwarfCompileUnit *CU = Entry.getCU();
1982 if (CU->getRanges().size() == 1) {
1983 // Grab the begin symbol from the first range as our base.
1984 const MCSymbol *Base = CU->getRanges()[0].getStart();
1985 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1986 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1987 } else {
1988 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1989 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1990 }
1992 emitDebugLocEntryLocation(Entry);
1993 }
1994 Asm->OutStreamer.EmitIntValue(0, Size);
1995 Asm->OutStreamer.EmitIntValue(0, Size);
1996 }
1997 }
1999 void DwarfDebug::emitDebugLocDWO() {
2000 Asm->OutStreamer.SwitchSection(
2001 Asm->getObjFileLowering().getDwarfLocDWOSection());
2002 for (const auto &DebugLoc : DotDebugLocEntries) {
2003 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2004 for (const auto &Entry : DebugLoc.List) {
2005 // Just always use start_length for now - at least that's one address
2006 // rather than two. We could get fancier and try to, say, reuse an
2007 // address we know we've emitted elsewhere (the start of the function?
2008 // The start of the CU or CU subrange that encloses this range?)
2009 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2010 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2011 Asm->EmitULEB128(idx);
2012 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2014 emitDebugLocEntryLocation(Entry);
2015 }
2016 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2017 }
2018 }
2020 struct ArangeSpan {
2021 const MCSymbol *Start, *End;
2022 };
2024 // Emit a debug aranges section, containing a CU lookup for any
2025 // address we can tie back to a CU.
2026 void DwarfDebug::emitDebugARanges() {
2027 // Start the dwarf aranges section.
2028 Asm->OutStreamer.SwitchSection(
2029 Asm->getObjFileLowering().getDwarfARangesSection());
2031 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2033 SpansType Spans;
2035 // Build a list of sections used.
2036 std::vector<const MCSection *> Sections;
2037 for (const auto &it : SectionMap) {
2038 const MCSection *Section = it.first;
2039 Sections.push_back(Section);
2040 }
2042 // Sort the sections into order.
2043 // This is only done to ensure consistent output order across different runs.
2044 std::sort(Sections.begin(), Sections.end(), SectionSort);
2046 // Build a set of address spans, sorted by CU.
2047 for (const MCSection *Section : Sections) {
2048 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2049 if (List.size() < 2)
2050 continue;
2052 // Sort the symbols by offset within the section.
2053 std::sort(List.begin(), List.end(),
2054 [&](const SymbolCU &A, const SymbolCU &B) {
2055 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2056 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2058 // Symbols with no order assigned should be placed at the end.
2059 // (e.g. section end labels)
2060 if (IA == 0)
2061 return false;
2062 if (IB == 0)
2063 return true;
2064 return IA < IB;
2065 });
2067 // If we have no section (e.g. common), just write out
2068 // individual spans for each symbol.
2069 if (!Section) {
2070 for (const SymbolCU &Cur : List) {
2071 ArangeSpan Span;
2072 Span.Start = Cur.Sym;
2073 Span.End = nullptr;
2074 if (Cur.CU)
2075 Spans[Cur.CU].push_back(Span);
2076 }
2077 } else {
2078 // Build spans between each label.
2079 const MCSymbol *StartSym = List[0].Sym;
2080 for (size_t n = 1, e = List.size(); n < e; n++) {
2081 const SymbolCU &Prev = List[n - 1];
2082 const SymbolCU &Cur = List[n];
2084 // Try and build the longest span we can within the same CU.
2085 if (Cur.CU != Prev.CU) {
2086 ArangeSpan Span;
2087 Span.Start = StartSym;
2088 Span.End = Cur.Sym;
2089 Spans[Prev.CU].push_back(Span);
2090 StartSym = Cur.Sym;
2091 }
2092 }
2093 }
2094 }
2096 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2098 // Build a list of CUs used.
2099 std::vector<DwarfCompileUnit *> CUs;
2100 for (const auto &it : Spans) {
2101 DwarfCompileUnit *CU = it.first;
2102 CUs.push_back(CU);
2103 }
2105 // Sort the CU list (again, to ensure consistent output order).
2106 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2107 return A->getUniqueID() < B->getUniqueID();
2108 });
2110 // Emit an arange table for each CU we used.
2111 for (DwarfCompileUnit *CU : CUs) {
2112 std::vector<ArangeSpan> &List = Spans[CU];
2114 // Emit size of content not including length itself.
2115 unsigned ContentSize =
2116 sizeof(int16_t) + // DWARF ARange version number
2117 sizeof(int32_t) + // Offset of CU in the .debug_info section
2118 sizeof(int8_t) + // Pointer Size (in bytes)
2119 sizeof(int8_t); // Segment Size (in bytes)
2121 unsigned TupleSize = PtrSize * 2;
2123 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2124 unsigned Padding =
2125 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2127 ContentSize += Padding;
2128 ContentSize += (List.size() + 1) * TupleSize;
2130 // For each compile unit, write the list of spans it covers.
2131 Asm->OutStreamer.AddComment("Length of ARange Set");
2132 Asm->EmitInt32(ContentSize);
2133 Asm->OutStreamer.AddComment("DWARF Arange version number");
2134 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2135 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2136 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2137 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2138 Asm->EmitInt8(PtrSize);
2139 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2140 Asm->EmitInt8(0);
2142 Asm->OutStreamer.EmitFill(Padding, 0xff);
2144 for (const ArangeSpan &Span : List) {
2145 Asm->EmitLabelReference(Span.Start, PtrSize);
2147 // Calculate the size as being from the span start to it's end.
2148 if (Span.End) {
2149 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2150 } else {
2151 // For symbols without an end marker (e.g. common), we
2152 // write a single arange entry containing just that one symbol.
2153 uint64_t Size = SymSize[Span.Start];
2154 if (Size == 0)
2155 Size = 1;
2157 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2158 }
2159 }
2161 Asm->OutStreamer.AddComment("ARange terminator");
2162 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2163 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2164 }
2165 }
2167 // Emit visible names into a debug ranges section.
2168 void DwarfDebug::emitDebugRanges() {
2169 // Start the dwarf ranges section.
2170 Asm->OutStreamer.SwitchSection(
2171 Asm->getObjFileLowering().getDwarfRangesSection());
2173 // Size for our labels.
2174 unsigned char Size = Asm->getDataLayout().getPointerSize();
2176 // Grab the specific ranges for the compile units in the module.
2177 for (const auto &I : CUMap) {
2178 DwarfCompileUnit *TheCU = I.second;
2180 // Iterate over the misc ranges for the compile units in the module.
2181 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2182 // Emit our symbol so we can find the beginning of the range.
2183 Asm->OutStreamer.EmitLabel(List.getSym());
2185 for (const RangeSpan &Range : List.getRanges()) {
2186 const MCSymbol *Begin = Range.getStart();
2187 const MCSymbol *End = Range.getEnd();
2188 assert(Begin && "Range without a begin symbol?");
2189 assert(End && "Range without an end symbol?");
2190 if (TheCU->getRanges().size() == 1) {
2191 // Grab the begin symbol from the first range as our base.
2192 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2193 Asm->EmitLabelDifference(Begin, Base, Size);
2194 Asm->EmitLabelDifference(End, Base, Size);
2195 } else {
2196 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2197 Asm->OutStreamer.EmitSymbolValue(End, Size);
2198 }
2199 }
2201 // And terminate the list with two 0 values.
2202 Asm->OutStreamer.EmitIntValue(0, Size);
2203 Asm->OutStreamer.EmitIntValue(0, Size);
2204 }
2206 // Now emit a range for the CU itself.
2207 if (TheCU->getRanges().size() > 1) {
2208 Asm->OutStreamer.EmitLabel(
2209 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2210 for (const RangeSpan &Range : TheCU->getRanges()) {
2211 const MCSymbol *Begin = Range.getStart();
2212 const MCSymbol *End = Range.getEnd();
2213 assert(Begin && "Range without a begin symbol?");
2214 assert(End && "Range without an end symbol?");
2215 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2216 Asm->OutStreamer.EmitSymbolValue(End, Size);
2217 }
2218 // And terminate the list with two 0 values.
2219 Asm->OutStreamer.EmitIntValue(0, Size);
2220 Asm->OutStreamer.EmitIntValue(0, Size);
2221 }
2222 }
2223 }
2225 // DWARF5 Experimental Separate Dwarf emitters.
2227 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2228 std::unique_ptr<DwarfUnit> NewU) {
2229 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2230 U.getCUNode().getSplitDebugFilename());
2232 if (!CompilationDir.empty())
2233 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2235 addGnuPubAttributes(*NewU, Die);
2237 SkeletonHolder.addUnit(std::move(NewU));
2238 }
2240 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2241 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2242 // DW_AT_addr_base, DW_AT_ranges_base.
2243 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2245 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2246 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2247 DwarfCompileUnit &NewCU = *OwnedUnit;
2248 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2249 DwarfInfoSectionSym);
2251 NewCU.initStmtList(DwarfLineSectionSym);
2253 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2255 return NewCU;
2256 }
2258 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_dwo_name,
2259 // DW_AT_addr_base.
2260 DwarfTypeUnit &DwarfDebug::constructSkeletonTU(DwarfTypeUnit &TU) {
2261 DwarfCompileUnit &CU = static_cast<DwarfCompileUnit &>(
2262 *SkeletonHolder.getUnits()[TU.getCU().getUniqueID()]);
2264 auto OwnedUnit = make_unique<DwarfTypeUnit>(TU.getUniqueID(), CU, Asm, this,
2265 &SkeletonHolder);
2266 DwarfTypeUnit &NewTU = *OwnedUnit;
2267 NewTU.setTypeSignature(TU.getTypeSignature());
2268 NewTU.setType(nullptr);
2269 NewTU.initSection(
2270 Asm->getObjFileLowering().getDwarfTypesSection(TU.getTypeSignature()));
2272 initSkeletonUnit(TU, NewTU.getUnitDie(), std::move(OwnedUnit));
2273 return NewTU;
2274 }
2276 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2277 // compile units that would normally be in debug_info.
2278 void DwarfDebug::emitDebugInfoDWO() {
2279 assert(useSplitDwarf() && "No split dwarf debug info?");
2280 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2281 // emit relocations into the dwo file.
2282 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2283 }
2285 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2286 // abbreviations for the .debug_info.dwo section.
2287 void DwarfDebug::emitDebugAbbrevDWO() {
2288 assert(useSplitDwarf() && "No split dwarf?");
2289 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2290 }
2292 void DwarfDebug::emitDebugLineDWO() {
2293 assert(useSplitDwarf() && "No split dwarf?");
2294 Asm->OutStreamer.SwitchSection(
2295 Asm->getObjFileLowering().getDwarfLineDWOSection());
2296 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2297 }
2299 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2300 // string section and is identical in format to traditional .debug_str
2301 // sections.
2302 void DwarfDebug::emitDebugStrDWO() {
2303 assert(useSplitDwarf() && "No split dwarf?");
2304 const MCSection *OffSec =
2305 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2306 const MCSymbol *StrSym = DwarfStrSectionSym;
2307 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2308 OffSec, StrSym);
2309 }
2311 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2312 if (!useSplitDwarf())
2313 return nullptr;
2314 if (SingleCU)
2315 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2316 return &SplitTypeUnitFileTable;
2317 }
2319 static uint64_t makeTypeSignature(StringRef Identifier) {
2320 MD5 Hash;
2321 Hash.update(Identifier);
2322 // ... take the least significant 8 bytes and return those. Our MD5
2323 // implementation always returns its results in little endian, swap bytes
2324 // appropriately.
2325 MD5::MD5Result Result;
2326 Hash.final(Result);
2327 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2328 }
2330 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2331 StringRef Identifier, DIE &RefDie,
2332 DICompositeType CTy) {
2333 // Fast path if we're building some type units and one has already used the
2334 // address pool we know we're going to throw away all this work anyway, so
2335 // don't bother building dependent types.
2336 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2337 return;
2339 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2340 if (TU) {
2341 CU.addDIETypeSignature(RefDie, *TU);
2342 return;
2343 }
2345 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2346 AddrPool.resetUsedFlag();
2348 auto OwnedUnit =
2349 make_unique<DwarfTypeUnit>(InfoHolder.getUnits().size(), CU, Asm, this,
2350 &InfoHolder, getDwoLineTable(CU));
2351 DwarfTypeUnit &NewTU = *OwnedUnit;
2352 DIE &UnitDie = NewTU.getUnitDie();
2353 TU = &NewTU;
2354 TypeUnitsUnderConstruction.push_back(
2355 std::make_pair(std::move(OwnedUnit), CTy));
2357 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2358 CU.getLanguage());
2360 uint64_t Signature = makeTypeSignature(Identifier);
2361 NewTU.setTypeSignature(Signature);
2363 if (!useSplitDwarf())
2364 CU.applyStmtList(UnitDie);
2366 // FIXME: Skip using COMDAT groups for type units in the .dwo file once tools
2367 // such as DWP ( http://gcc.gnu.org/wiki/DebugFissionDWP ) can cope with it.
2368 NewTU.initSection(
2369 useSplitDwarf()
2370 ? Asm->getObjFileLowering().getDwarfTypesDWOSection(Signature)
2371 : Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2373 NewTU.setType(NewTU.createTypeDIE(CTy));
2375 if (TopLevelType) {
2376 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2377 TypeUnitsUnderConstruction.clear();
2379 // Types referencing entries in the address table cannot be placed in type
2380 // units.
2381 if (AddrPool.hasBeenUsed()) {
2383 // Remove all the types built while building this type.
2384 // This is pessimistic as some of these types might not be dependent on
2385 // the type that used an address.
2386 for (const auto &TU : TypeUnitsToAdd)
2387 DwarfTypeUnits.erase(TU.second);
2389 // Construct this type in the CU directly.
2390 // This is inefficient because all the dependent types will be rebuilt
2391 // from scratch, including building them in type units, discovering that
2392 // they depend on addresses, throwing them out and rebuilding them.
2393 CU.constructTypeDIE(RefDie, CTy);
2394 return;
2395 }
2397 // If the type wasn't dependent on fission addresses, finish adding the type
2398 // and all its dependent types.
2399 for (auto &TU : TypeUnitsToAdd) {
2400 if (useSplitDwarf())
2401 TU.first->setSkeleton(constructSkeletonTU(*TU.first));
2402 InfoHolder.addUnit(std::move(TU.first));
2403 }
2404 }
2405 CU.addDIETypeSignature(RefDie, NewTU);
2406 }
2408 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2409 MCSymbol *Begin, MCSymbol *End) {
2410 assert(Begin && "Begin label should not be null!");
2411 assert(End && "End label should not be null!");
2412 assert(Begin->isDefined() && "Invalid starting label");
2413 assert(End->isDefined() && "Invalid end label");
2415 Unit.addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
2416 if (DwarfVersion < 4)
2417 Unit.addLabelAddress(D, dwarf::DW_AT_high_pc, End);
2418 else
2419 Unit.addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
2420 }
2422 // Accelerator table mutators - add each name along with its companion
2423 // DIE to the proper table while ensuring that the name that we're going
2424 // to reference is in the string table. We do this since the names we
2425 // add may not only be identical to the names in the DIE.
2426 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2427 if (!useDwarfAccelTables())
2428 return;
2429 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2430 &Die);
2431 }
2433 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2434 if (!useDwarfAccelTables())
2435 return;
2436 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2437 &Die);
2438 }
2440 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2441 if (!useDwarfAccelTables())
2442 return;
2443 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2444 &Die);
2445 }
2447 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2448 if (!useDwarfAccelTables())
2449 return;
2450 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2451 &Die);
2452 }