e4e19cc91f3b3d7e185f362f96ae750e3d61bd4c
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 // History contains relevant DBG_VALUE instructions for DV and instructions
1157 // clobbering it.
1158 const SmallVectorImpl<const MachineInstr *> &History = I.second;
1159 if (History.empty())
1160 continue;
1161 const MachineInstr *MInsn = History.front();
1163 LexicalScope *Scope = nullptr;
1164 if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
1165 DISubprogram(DV.getContext()).describes(CurFn->getFunction()))
1166 Scope = LScopes.getCurrentFunctionScope();
1167 else if (MDNode *IA = DV.getInlinedAt()) {
1168 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1169 Scope = LScopes.findInlinedScope(DebugLoc::get(
1170 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1171 } else
1172 Scope = LScopes.findLexicalScope(DV.getContext());
1173 // If variable scope is not found then skip this variable.
1174 if (!Scope)
1175 continue;
1177 Processed.insert(DV);
1178 assert(MInsn->isDebugValue() && "History must begin with debug value");
1179 DbgVariable *AbsVar = findAbstractVariable(DV, MInsn->getDebugLoc());
1180 DbgVariable *RegVar = new DbgVariable(DV, AbsVar, this);
1181 if (!addCurrentFnArgument(RegVar, Scope))
1182 addScopeVariable(Scope, RegVar);
1183 if (AbsVar)
1184 AbsVar->setMInsn(MInsn);
1186 // Simplify ranges that are fully coalesced.
1187 if (History.size() <= 1 ||
1188 (History.size() == 2 && MInsn->isIdenticalTo(History.back()))) {
1189 RegVar->setMInsn(MInsn);
1190 continue;
1191 }
1193 // Handle multiple DBG_VALUE instructions describing one variable.
1194 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1196 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1197 DebugLocList &LocList = DotDebugLocEntries.back();
1198 LocList.Label =
1199 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1200 SmallVector<DebugLocEntry, 4> &DebugLoc = LocList.List;
1201 for (SmallVectorImpl<const MachineInstr *>::const_iterator
1202 HI = History.begin(),
1203 HE = History.end();
1204 HI != HE; ++HI) {
1205 const MachineInstr *Begin = *HI;
1206 assert(Begin->isDebugValue() && "Invalid History entry");
1208 // Check if DBG_VALUE is truncating a range.
1209 if (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
1210 !Begin->getOperand(0).getReg())
1211 continue;
1213 // Compute the range for a register location.
1214 const MCSymbol *FLabel = getLabelBeforeInsn(Begin);
1215 const MCSymbol *SLabel = nullptr;
1217 if (HI + 1 == HE)
1218 // If Begin is the last instruction in History then its value is valid
1219 // until the end of the function.
1220 SLabel = FunctionEndSym;
1221 else {
1222 const MachineInstr *End = HI[1];
1223 DEBUG(dbgs() << "DotDebugLoc Pair:\n"
1224 << "\t" << *Begin << "\t" << *End << "\n");
1225 if (End->isDebugValue() && End->getDebugVariable() == DV)
1226 SLabel = getLabelBeforeInsn(End);
1227 else {
1228 // End is clobbering the range.
1229 SLabel = getLabelAfterInsn(End);
1230 assert(SLabel && "Forgot label after clobber instruction");
1231 ++HI;
1232 }
1233 }
1235 // The value is valid until the next DBG_VALUE or clobber.
1236 DebugLocEntry Loc(FLabel, SLabel, getDebugLocValue(Begin), TheCU);
1237 if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc))
1238 DebugLoc.push_back(std::move(Loc));
1239 }
1240 }
1242 // Collect info for variables that were optimized out.
1243 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1244 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1245 DIVariable DV(Variables.getElement(i));
1246 assert(DV.isVariable());
1247 if (!Processed.insert(DV))
1248 continue;
1249 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext()))
1250 addScopeVariable(
1251 Scope,
1252 new DbgVariable(DV, findAbstractVariable(DV, Scope->getScopeNode()),
1253 this));
1254 }
1255 }
1257 // Return Label preceding the instruction.
1258 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1259 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1260 assert(Label && "Didn't insert label before instruction");
1261 return Label;
1262 }
1264 // Return Label immediately following the instruction.
1265 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1266 return LabelsAfterInsn.lookup(MI);
1267 }
1269 // Process beginning of an instruction.
1270 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1271 assert(CurMI == nullptr);
1272 CurMI = MI;
1273 // Check if source location changes, but ignore DBG_VALUE locations.
1274 if (!MI->isDebugValue()) {
1275 DebugLoc DL = MI->getDebugLoc();
1276 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1277 unsigned Flags = 0;
1278 PrevInstLoc = DL;
1279 if (DL == PrologEndLoc) {
1280 Flags |= DWARF2_FLAG_PROLOGUE_END;
1281 PrologEndLoc = DebugLoc();
1282 }
1283 if (PrologEndLoc.isUnknown())
1284 Flags |= DWARF2_FLAG_IS_STMT;
1286 if (!DL.isUnknown()) {
1287 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1288 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1289 } else
1290 recordSourceLine(0, 0, nullptr, 0);
1291 }
1292 }
1294 // Insert labels where requested.
1295 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1296 LabelsBeforeInsn.find(MI);
1298 // No label needed.
1299 if (I == LabelsBeforeInsn.end())
1300 return;
1302 // Label already assigned.
1303 if (I->second)
1304 return;
1306 if (!PrevLabel) {
1307 PrevLabel = MMI->getContext().CreateTempSymbol();
1308 Asm->OutStreamer.EmitLabel(PrevLabel);
1309 }
1310 I->second = PrevLabel;
1311 }
1313 // Process end of an instruction.
1314 void DwarfDebug::endInstruction() {
1315 assert(CurMI != nullptr);
1316 // Don't create a new label after DBG_VALUE instructions.
1317 // They don't generate code.
1318 if (!CurMI->isDebugValue())
1319 PrevLabel = nullptr;
1321 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1322 LabelsAfterInsn.find(CurMI);
1323 CurMI = nullptr;
1325 // No label needed.
1326 if (I == LabelsAfterInsn.end())
1327 return;
1329 // Label already assigned.
1330 if (I->second)
1331 return;
1333 // We need a label after this instruction.
1334 if (!PrevLabel) {
1335 PrevLabel = MMI->getContext().CreateTempSymbol();
1336 Asm->OutStreamer.EmitLabel(PrevLabel);
1337 }
1338 I->second = PrevLabel;
1339 }
1341 // Each LexicalScope has first instruction and last instruction to mark
1342 // beginning and end of a scope respectively. Create an inverse map that list
1343 // scopes starts (and ends) with an instruction. One instruction may start (or
1344 // end) multiple scopes. Ignore scopes that are not reachable.
1345 void DwarfDebug::identifyScopeMarkers() {
1346 SmallVector<LexicalScope *, 4> WorkList;
1347 WorkList.push_back(LScopes.getCurrentFunctionScope());
1348 while (!WorkList.empty()) {
1349 LexicalScope *S = WorkList.pop_back_val();
1351 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1352 if (!Children.empty())
1353 WorkList.append(Children.begin(), Children.end());
1355 if (S->isAbstractScope())
1356 continue;
1358 for (const InsnRange &R : S->getRanges()) {
1359 assert(R.first && "InsnRange does not have first instruction!");
1360 assert(R.second && "InsnRange does not have second instruction!");
1361 requestLabelBeforeInsn(R.first);
1362 requestLabelAfterInsn(R.second);
1363 }
1364 }
1365 }
1367 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1368 // First known non-DBG_VALUE and non-frame setup location marks
1369 // the beginning of the function body.
1370 for (const auto &MBB : *MF)
1371 for (const auto &MI : MBB)
1372 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1373 !MI.getDebugLoc().isUnknown())
1374 return MI.getDebugLoc();
1375 return DebugLoc();
1376 }
1378 // Gather pre-function debug information. Assumes being called immediately
1379 // after the function entry point has been emitted.
1380 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1381 CurFn = MF;
1383 // If there's no debug info for the function we're not going to do anything.
1384 if (!MMI->hasDebugInfo())
1385 return;
1387 // Grab the lexical scopes for the function, if we don't have any of those
1388 // then we're not going to be able to do anything.
1389 LScopes.initialize(*MF);
1390 if (LScopes.empty())
1391 return;
1393 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1395 // Make sure that each lexical scope will have a begin/end label.
1396 identifyScopeMarkers();
1398 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1399 // belongs to so that we add to the correct per-cu line table in the
1400 // non-asm case.
1401 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1402 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1403 assert(TheCU && "Unable to find compile unit!");
1404 if (Asm->OutStreamer.hasRawTextSupport())
1405 // Use a single line table if we are generating assembly.
1406 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1407 else
1408 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1410 // Emit a label for the function so that we have a beginning address.
1411 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1412 // Assumes in correct section after the entry point.
1413 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1415 // Calculate history for local variables.
1416 calculateDbgValueHistory(MF, Asm->TM.getRegisterInfo(), DbgValues);
1418 // Request labels for the full history.
1419 for (auto &I : DbgValues) {
1420 const SmallVectorImpl<const MachineInstr *> &History = I.second;
1421 if (History.empty())
1422 continue;
1424 // The first mention of a function argument gets the FunctionBeginSym
1425 // label, so arguments are visible when breaking at function entry.
1426 DIVariable DV(I.first);
1427 if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
1428 getDISubprogram(DV.getContext()).describes(MF->getFunction()))
1429 LabelsBeforeInsn[History.front()] = FunctionBeginSym;
1431 for (const MachineInstr *MI : History) {
1432 if (MI->isDebugValue() && MI->getDebugVariable() == DV)
1433 requestLabelBeforeInsn(MI);
1434 else
1435 requestLabelAfterInsn(MI);
1436 }
1437 }
1439 PrevInstLoc = DebugLoc();
1440 PrevLabel = FunctionBeginSym;
1442 // Record beginning of function.
1443 PrologEndLoc = findPrologueEndLoc(MF);
1444 if (!PrologEndLoc.isUnknown()) {
1445 DebugLoc FnStartDL =
1446 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1447 recordSourceLine(
1448 FnStartDL.getLine(), FnStartDL.getCol(),
1449 FnStartDL.getScope(MF->getFunction()->getContext()),
1450 // We'd like to list the prologue as "not statements" but GDB behaves
1451 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1452 DWARF2_FLAG_IS_STMT);
1453 }
1454 }
1456 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1457 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1458 DIVariable DV = Var->getVariable();
1459 // Variables with positive arg numbers are parameters.
1460 if (unsigned ArgNum = DV.getArgNumber()) {
1461 // Keep all parameters in order at the start of the variable list to ensure
1462 // function types are correct (no out-of-order parameters)
1463 //
1464 // This could be improved by only doing it for optimized builds (unoptimized
1465 // builds have the right order to begin with), searching from the back (this
1466 // would catch the unoptimized case quickly), or doing a binary search
1467 // rather than linear search.
1468 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1469 while (I != Vars.end()) {
1470 unsigned CurNum = (*I)->getVariable().getArgNumber();
1471 // A local (non-parameter) variable has been found, insert immediately
1472 // before it.
1473 if (CurNum == 0)
1474 break;
1475 // A later indexed parameter has been found, insert immediately before it.
1476 if (CurNum > ArgNum)
1477 break;
1478 ++I;
1479 }
1480 Vars.insert(I, Var);
1481 return;
1482 }
1484 Vars.push_back(Var);
1485 }
1487 // Gather and emit post-function debug information.
1488 void DwarfDebug::endFunction(const MachineFunction *MF) {
1489 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1490 // though the beginFunction may not be called at all.
1491 // We should handle both cases.
1492 if (!CurFn)
1493 CurFn = MF;
1494 else
1495 assert(CurFn == MF);
1496 assert(CurFn != nullptr);
1498 if (!MMI->hasDebugInfo() || LScopes.empty()) {
1499 // If we don't have a lexical scope for this function then there will
1500 // be a hole in the range information. Keep note of this by setting the
1501 // previously used section to nullptr.
1502 PrevSection = nullptr;
1503 PrevCU = nullptr;
1504 CurFn = nullptr;
1505 return;
1506 }
1508 // Define end label for subprogram.
1509 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1510 // Assumes in correct section after the entry point.
1511 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1513 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1514 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1516 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1517 collectVariableInfo(ProcessedVars);
1519 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1520 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1522 // Construct abstract scopes.
1523 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1524 DISubprogram SP(AScope->getScopeNode());
1525 if (!SP.isSubprogram())
1526 continue;
1527 // Collect info for variables that were optimized out.
1528 DIArray Variables = SP.getVariables();
1529 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1530 DIVariable DV(Variables.getElement(i));
1531 assert(DV && DV.isVariable());
1532 if (!ProcessedVars.insert(DV))
1533 continue;
1534 findAbstractVariable(DV, DV.getContext());
1535 }
1536 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1537 }
1539 DIE &CurFnDIE = constructSubprogramScopeDIE(TheCU, FnScope);
1540 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
1541 TheCU.addFlag(CurFnDIE, dwarf::DW_AT_APPLE_omit_frame_ptr);
1543 // Add the range of this function to the list of ranges for the CU.
1544 RangeSpan Span(FunctionBeginSym, FunctionEndSym);
1545 TheCU.addRange(std::move(Span));
1546 PrevSection = Asm->getCurrentSection();
1547 PrevCU = &TheCU;
1549 // Clear debug info
1550 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1551 // DbgVariables except those that are also in AbstractVariables (since they
1552 // can be used cross-function)
1553 for (const auto &I : ScopeVariables)
1554 for (const auto *Var : I.second)
1555 if (!AbstractVariables.count(Var->getVariable()) || Var->getAbstractVariable())
1556 delete Var;
1557 ScopeVariables.clear();
1558 DeleteContainerPointers(CurrentFnArguments);
1559 DbgValues.clear();
1560 LabelsBeforeInsn.clear();
1561 LabelsAfterInsn.clear();
1562 PrevLabel = nullptr;
1563 CurFn = nullptr;
1564 }
1566 // Register a source line with debug info. Returns the unique label that was
1567 // emitted and which provides correspondence to the source line list.
1568 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1569 unsigned Flags) {
1570 StringRef Fn;
1571 StringRef Dir;
1572 unsigned Src = 1;
1573 unsigned Discriminator = 0;
1574 if (DIScope Scope = DIScope(S)) {
1575 assert(Scope.isScope());
1576 Fn = Scope.getFilename();
1577 Dir = Scope.getDirectory();
1578 if (Scope.isLexicalBlock())
1579 Discriminator = DILexicalBlock(S).getDiscriminator();
1581 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1582 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1583 .getOrCreateSourceID(Fn, Dir);
1584 }
1585 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1586 Discriminator, Fn);
1587 }
1589 //===----------------------------------------------------------------------===//
1590 // Emit Methods
1591 //===----------------------------------------------------------------------===//
1593 // Emit initial Dwarf sections with a label at the start of each one.
1594 void DwarfDebug::emitSectionLabels() {
1595 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1597 // Dwarf sections base addresses.
1598 DwarfInfoSectionSym =
1599 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1600 if (useSplitDwarf())
1601 DwarfInfoDWOSectionSym =
1602 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1603 DwarfAbbrevSectionSym =
1604 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1605 if (useSplitDwarf())
1606 DwarfAbbrevDWOSectionSym = emitSectionSym(
1607 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1608 if (GenerateARangeSection)
1609 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1611 DwarfLineSectionSym =
1612 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1613 if (GenerateGnuPubSections) {
1614 DwarfGnuPubNamesSectionSym =
1615 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1616 DwarfGnuPubTypesSectionSym =
1617 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1618 } else if (HasDwarfPubSections) {
1619 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1620 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1621 }
1623 DwarfStrSectionSym =
1624 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1625 if (useSplitDwarf()) {
1626 DwarfStrDWOSectionSym =
1627 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1628 DwarfAddrSectionSym =
1629 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1630 DwarfDebugLocSectionSym =
1631 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1632 } else
1633 DwarfDebugLocSectionSym =
1634 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1635 DwarfDebugRangeSectionSym =
1636 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1637 }
1639 // Recursively emits a debug information entry.
1640 void DwarfDebug::emitDIE(DIE &Die) {
1641 // Get the abbreviation for this DIE.
1642 const DIEAbbrev &Abbrev = Die.getAbbrev();
1644 // Emit the code (index) for the abbreviation.
1645 if (Asm->isVerbose())
1646 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1647 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1648 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1649 dwarf::TagString(Abbrev.getTag()));
1650 Asm->EmitULEB128(Abbrev.getNumber());
1652 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1653 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1655 // Emit the DIE attribute values.
1656 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1657 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1658 dwarf::Form Form = AbbrevData[i].getForm();
1659 assert(Form && "Too many attributes for DIE (check abbreviation)");
1661 if (Asm->isVerbose()) {
1662 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1663 if (Attr == dwarf::DW_AT_accessibility)
1664 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1665 cast<DIEInteger>(Values[i])->getValue()));
1666 }
1668 // Emit an attribute using the defined form.
1669 Values[i]->EmitValue(Asm, Form);
1670 }
1672 // Emit the DIE children if any.
1673 if (Abbrev.hasChildren()) {
1674 for (auto &Child : Die.getChildren())
1675 emitDIE(*Child);
1677 Asm->OutStreamer.AddComment("End Of Children Mark");
1678 Asm->EmitInt8(0);
1679 }
1680 }
1682 // Emit the debug info section.
1683 void DwarfDebug::emitDebugInfo() {
1684 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1686 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1687 }
1689 // Emit the abbreviation section.
1690 void DwarfDebug::emitAbbreviations() {
1691 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1693 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1694 }
1696 // Emit the last address of the section and the end of the line matrix.
1697 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1698 // Define last address of section.
1699 Asm->OutStreamer.AddComment("Extended Op");
1700 Asm->EmitInt8(0);
1702 Asm->OutStreamer.AddComment("Op size");
1703 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1704 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1705 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1707 Asm->OutStreamer.AddComment("Section end label");
1709 Asm->OutStreamer.EmitSymbolValue(
1710 Asm->GetTempSymbol("section_end", SectionEnd),
1711 Asm->getDataLayout().getPointerSize());
1713 // Mark end of matrix.
1714 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1715 Asm->EmitInt8(0);
1716 Asm->EmitInt8(1);
1717 Asm->EmitInt8(1);
1718 }
1720 // Emit visible names into a hashed accelerator table section.
1721 void DwarfDebug::emitAccelNames() {
1722 AccelNames.FinalizeTable(Asm, "Names");
1723 Asm->OutStreamer.SwitchSection(
1724 Asm->getObjFileLowering().getDwarfAccelNamesSection());
1725 MCSymbol *SectionBegin = Asm->GetTempSymbol("names_begin");
1726 Asm->OutStreamer.EmitLabel(SectionBegin);
1728 // Emit the full data.
1729 AccelNames.Emit(Asm, SectionBegin, &InfoHolder);
1730 }
1732 // Emit objective C classes and categories into a hashed accelerator table
1733 // section.
1734 void DwarfDebug::emitAccelObjC() {
1735 AccelObjC.FinalizeTable(Asm, "ObjC");
1736 Asm->OutStreamer.SwitchSection(
1737 Asm->getObjFileLowering().getDwarfAccelObjCSection());
1738 MCSymbol *SectionBegin = Asm->GetTempSymbol("objc_begin");
1739 Asm->OutStreamer.EmitLabel(SectionBegin);
1741 // Emit the full data.
1742 AccelObjC.Emit(Asm, SectionBegin, &InfoHolder);
1743 }
1745 // Emit namespace dies into a hashed accelerator table.
1746 void DwarfDebug::emitAccelNamespaces() {
1747 AccelNamespace.FinalizeTable(Asm, "namespac");
1748 Asm->OutStreamer.SwitchSection(
1749 Asm->getObjFileLowering().getDwarfAccelNamespaceSection());
1750 MCSymbol *SectionBegin = Asm->GetTempSymbol("namespac_begin");
1751 Asm->OutStreamer.EmitLabel(SectionBegin);
1753 // Emit the full data.
1754 AccelNamespace.Emit(Asm, SectionBegin, &InfoHolder);
1755 }
1757 // Emit type dies into a hashed accelerator table.
1758 void DwarfDebug::emitAccelTypes() {
1760 AccelTypes.FinalizeTable(Asm, "types");
1761 Asm->OutStreamer.SwitchSection(
1762 Asm->getObjFileLowering().getDwarfAccelTypesSection());
1763 MCSymbol *SectionBegin = Asm->GetTempSymbol("types_begin");
1764 Asm->OutStreamer.EmitLabel(SectionBegin);
1766 // Emit the full data.
1767 AccelTypes.Emit(Asm, SectionBegin, &InfoHolder);
1768 }
1770 // Public name handling.
1771 // The format for the various pubnames:
1772 //
1773 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1774 // for the DIE that is named.
1775 //
1776 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1777 // into the CU and the index value is computed according to the type of value
1778 // for the DIE that is named.
1779 //
1780 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1781 // it's the offset within the debug_info/debug_types dwo section, however, the
1782 // reference in the pubname header doesn't change.
1784 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1785 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1786 const DIE *Die) {
1787 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1789 // We could have a specification DIE that has our most of our knowledge,
1790 // look for that now.
1791 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1792 if (SpecVal) {
1793 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1794 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1795 Linkage = dwarf::GIEL_EXTERNAL;
1796 } else if (Die->findAttribute(dwarf::DW_AT_external))
1797 Linkage = dwarf::GIEL_EXTERNAL;
1799 switch (Die->getTag()) {
1800 case dwarf::DW_TAG_class_type:
1801 case dwarf::DW_TAG_structure_type:
1802 case dwarf::DW_TAG_union_type:
1803 case dwarf::DW_TAG_enumeration_type:
1804 return dwarf::PubIndexEntryDescriptor(
1805 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1806 ? dwarf::GIEL_STATIC
1807 : dwarf::GIEL_EXTERNAL);
1808 case dwarf::DW_TAG_typedef:
1809 case dwarf::DW_TAG_base_type:
1810 case dwarf::DW_TAG_subrange_type:
1811 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1812 case dwarf::DW_TAG_namespace:
1813 return dwarf::GIEK_TYPE;
1814 case dwarf::DW_TAG_subprogram:
1815 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1816 case dwarf::DW_TAG_constant:
1817 case dwarf::DW_TAG_variable:
1818 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1819 case dwarf::DW_TAG_enumerator:
1820 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1821 dwarf::GIEL_STATIC);
1822 default:
1823 return dwarf::GIEK_NONE;
1824 }
1825 }
1827 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1828 ///
1829 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1830 const MCSection *PSec =
1831 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1832 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1834 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1835 }
1837 void DwarfDebug::emitDebugPubSection(
1838 bool GnuStyle, const MCSection *PSec, StringRef Name,
1839 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1840 for (const auto &NU : CUMap) {
1841 DwarfCompileUnit *TheU = NU.second;
1843 const auto &Globals = (TheU->*Accessor)();
1845 if (Globals.empty())
1846 continue;
1848 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1849 TheU = Skeleton;
1850 unsigned ID = TheU->getUniqueID();
1852 // Start the dwarf pubnames section.
1853 Asm->OutStreamer.SwitchSection(PSec);
1855 // Emit the header.
1856 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1857 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1858 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1859 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1861 Asm->OutStreamer.EmitLabel(BeginLabel);
1863 Asm->OutStreamer.AddComment("DWARF Version");
1864 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1866 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1867 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1869 Asm->OutStreamer.AddComment("Compilation Unit Length");
1870 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
1872 // Emit the pubnames for this compilation unit.
1873 for (const auto &GI : Globals) {
1874 const char *Name = GI.getKeyData();
1875 const DIE *Entity = GI.second;
1877 Asm->OutStreamer.AddComment("DIE offset");
1878 Asm->EmitInt32(Entity->getOffset());
1880 if (GnuStyle) {
1881 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1882 Asm->OutStreamer.AddComment(
1883 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1884 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1885 Asm->EmitInt8(Desc.toBits());
1886 }
1888 Asm->OutStreamer.AddComment("External Name");
1889 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1890 }
1892 Asm->OutStreamer.AddComment("End Mark");
1893 Asm->EmitInt32(0);
1894 Asm->OutStreamer.EmitLabel(EndLabel);
1895 }
1896 }
1898 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1899 const MCSection *PSec =
1900 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1901 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1903 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
1904 }
1906 // Emit visible names into a debug str section.
1907 void DwarfDebug::emitDebugStr() {
1908 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1909 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1910 }
1912 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1913 const DebugLocEntry &Entry) {
1914 assert(Entry.getValues().size() == 1 &&
1915 "multi-value entries are not supported yet.");
1916 const DebugLocEntry::Value Value = Entry.getValues()[0];
1917 DIVariable DV(Value.getVariable());
1918 if (Value.isInt()) {
1919 DIBasicType BTy(resolve(DV.getType()));
1920 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1921 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
1922 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
1923 Streamer.EmitSLEB128(Value.getInt());
1924 } else {
1925 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
1926 Streamer.EmitULEB128(Value.getInt());
1927 }
1928 } else if (Value.isLocation()) {
1929 MachineLocation Loc = Value.getLoc();
1930 if (!DV.hasComplexAddress())
1931 // Regular entry.
1932 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1933 else {
1934 // Complex address entry.
1935 unsigned N = DV.getNumAddrElements();
1936 unsigned i = 0;
1937 if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
1938 if (Loc.getOffset()) {
1939 i = 2;
1940 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1941 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1942 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1943 Streamer.EmitSLEB128(DV.getAddrElement(1));
1944 } else {
1945 // If first address element is OpPlus then emit
1946 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
1947 MachineLocation TLoc(Loc.getReg(), DV.getAddrElement(1));
1948 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
1949 i = 2;
1950 }
1951 } else {
1952 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1953 }
1955 // Emit remaining complex address elements.
1956 for (; i < N; ++i) {
1957 uint64_t Element = DV.getAddrElement(i);
1958 if (Element == DIBuilder::OpPlus) {
1959 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
1960 Streamer.EmitULEB128(DV.getAddrElement(++i));
1961 } else if (Element == DIBuilder::OpDeref) {
1962 if (!Loc.isReg())
1963 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
1964 } else
1965 llvm_unreachable("unknown Opcode found in complex address");
1966 }
1967 }
1968 }
1969 // else ... ignore constant fp. There is not any good way to
1970 // to represent them here in dwarf.
1971 // FIXME: ^
1972 }
1974 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1975 Asm->OutStreamer.AddComment("Loc expr size");
1976 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1977 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1978 Asm->EmitLabelDifference(end, begin, 2);
1979 Asm->OutStreamer.EmitLabel(begin);
1980 // Emit the entry.
1981 APByteStreamer Streamer(*Asm);
1982 emitDebugLocEntry(Streamer, Entry);
1983 // Close the range.
1984 Asm->OutStreamer.EmitLabel(end);
1985 }
1987 // Emit locations into the debug loc section.
1988 void DwarfDebug::emitDebugLoc() {
1989 // Start the dwarf loc section.
1990 Asm->OutStreamer.SwitchSection(
1991 Asm->getObjFileLowering().getDwarfLocSection());
1992 unsigned char Size = Asm->getDataLayout().getPointerSize();
1993 for (const auto &DebugLoc : DotDebugLocEntries) {
1994 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1995 for (const auto &Entry : DebugLoc.List) {
1996 // Set up the range. This range is relative to the entry point of the
1997 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1998 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1999 const DwarfCompileUnit *CU = Entry.getCU();
2000 if (CU->getRanges().size() == 1) {
2001 // Grab the begin symbol from the first range as our base.
2002 const MCSymbol *Base = CU->getRanges()[0].getStart();
2003 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
2004 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
2005 } else {
2006 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
2007 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
2008 }
2010 emitDebugLocEntryLocation(Entry);
2011 }
2012 Asm->OutStreamer.EmitIntValue(0, Size);
2013 Asm->OutStreamer.EmitIntValue(0, Size);
2014 }
2015 }
2017 void DwarfDebug::emitDebugLocDWO() {
2018 Asm->OutStreamer.SwitchSection(
2019 Asm->getObjFileLowering().getDwarfLocDWOSection());
2020 for (const auto &DebugLoc : DotDebugLocEntries) {
2021 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2022 for (const auto &Entry : DebugLoc.List) {
2023 // Just always use start_length for now - at least that's one address
2024 // rather than two. We could get fancier and try to, say, reuse an
2025 // address we know we've emitted elsewhere (the start of the function?
2026 // The start of the CU or CU subrange that encloses this range?)
2027 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2028 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2029 Asm->EmitULEB128(idx);
2030 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2032 emitDebugLocEntryLocation(Entry);
2033 }
2034 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2035 }
2036 }
2038 struct ArangeSpan {
2039 const MCSymbol *Start, *End;
2040 };
2042 // Emit a debug aranges section, containing a CU lookup for any
2043 // address we can tie back to a CU.
2044 void DwarfDebug::emitDebugARanges() {
2045 // Start the dwarf aranges section.
2046 Asm->OutStreamer.SwitchSection(
2047 Asm->getObjFileLowering().getDwarfARangesSection());
2049 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2051 SpansType Spans;
2053 // Build a list of sections used.
2054 std::vector<const MCSection *> Sections;
2055 for (const auto &it : SectionMap) {
2056 const MCSection *Section = it.first;
2057 Sections.push_back(Section);
2058 }
2060 // Sort the sections into order.
2061 // This is only done to ensure consistent output order across different runs.
2062 std::sort(Sections.begin(), Sections.end(), SectionSort);
2064 // Build a set of address spans, sorted by CU.
2065 for (const MCSection *Section : Sections) {
2066 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2067 if (List.size() < 2)
2068 continue;
2070 // Sort the symbols by offset within the section.
2071 std::sort(List.begin(), List.end(),
2072 [&](const SymbolCU &A, const SymbolCU &B) {
2073 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2074 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2076 // Symbols with no order assigned should be placed at the end.
2077 // (e.g. section end labels)
2078 if (IA == 0)
2079 return false;
2080 if (IB == 0)
2081 return true;
2082 return IA < IB;
2083 });
2085 // If we have no section (e.g. common), just write out
2086 // individual spans for each symbol.
2087 if (!Section) {
2088 for (const SymbolCU &Cur : List) {
2089 ArangeSpan Span;
2090 Span.Start = Cur.Sym;
2091 Span.End = nullptr;
2092 if (Cur.CU)
2093 Spans[Cur.CU].push_back(Span);
2094 }
2095 } else {
2096 // Build spans between each label.
2097 const MCSymbol *StartSym = List[0].Sym;
2098 for (size_t n = 1, e = List.size(); n < e; n++) {
2099 const SymbolCU &Prev = List[n - 1];
2100 const SymbolCU &Cur = List[n];
2102 // Try and build the longest span we can within the same CU.
2103 if (Cur.CU != Prev.CU) {
2104 ArangeSpan Span;
2105 Span.Start = StartSym;
2106 Span.End = Cur.Sym;
2107 Spans[Prev.CU].push_back(Span);
2108 StartSym = Cur.Sym;
2109 }
2110 }
2111 }
2112 }
2114 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2116 // Build a list of CUs used.
2117 std::vector<DwarfCompileUnit *> CUs;
2118 for (const auto &it : Spans) {
2119 DwarfCompileUnit *CU = it.first;
2120 CUs.push_back(CU);
2121 }
2123 // Sort the CU list (again, to ensure consistent output order).
2124 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2125 return A->getUniqueID() < B->getUniqueID();
2126 });
2128 // Emit an arange table for each CU we used.
2129 for (DwarfCompileUnit *CU : CUs) {
2130 std::vector<ArangeSpan> &List = Spans[CU];
2132 // Emit size of content not including length itself.
2133 unsigned ContentSize =
2134 sizeof(int16_t) + // DWARF ARange version number
2135 sizeof(int32_t) + // Offset of CU in the .debug_info section
2136 sizeof(int8_t) + // Pointer Size (in bytes)
2137 sizeof(int8_t); // Segment Size (in bytes)
2139 unsigned TupleSize = PtrSize * 2;
2141 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2142 unsigned Padding =
2143 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2145 ContentSize += Padding;
2146 ContentSize += (List.size() + 1) * TupleSize;
2148 // For each compile unit, write the list of spans it covers.
2149 Asm->OutStreamer.AddComment("Length of ARange Set");
2150 Asm->EmitInt32(ContentSize);
2151 Asm->OutStreamer.AddComment("DWARF Arange version number");
2152 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2153 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2154 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2155 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2156 Asm->EmitInt8(PtrSize);
2157 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2158 Asm->EmitInt8(0);
2160 Asm->OutStreamer.EmitFill(Padding, 0xff);
2162 for (const ArangeSpan &Span : List) {
2163 Asm->EmitLabelReference(Span.Start, PtrSize);
2165 // Calculate the size as being from the span start to it's end.
2166 if (Span.End) {
2167 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2168 } else {
2169 // For symbols without an end marker (e.g. common), we
2170 // write a single arange entry containing just that one symbol.
2171 uint64_t Size = SymSize[Span.Start];
2172 if (Size == 0)
2173 Size = 1;
2175 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2176 }
2177 }
2179 Asm->OutStreamer.AddComment("ARange terminator");
2180 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2181 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2182 }
2183 }
2185 // Emit visible names into a debug ranges section.
2186 void DwarfDebug::emitDebugRanges() {
2187 // Start the dwarf ranges section.
2188 Asm->OutStreamer.SwitchSection(
2189 Asm->getObjFileLowering().getDwarfRangesSection());
2191 // Size for our labels.
2192 unsigned char Size = Asm->getDataLayout().getPointerSize();
2194 // Grab the specific ranges for the compile units in the module.
2195 for (const auto &I : CUMap) {
2196 DwarfCompileUnit *TheCU = I.second;
2198 // Iterate over the misc ranges for the compile units in the module.
2199 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2200 // Emit our symbol so we can find the beginning of the range.
2201 Asm->OutStreamer.EmitLabel(List.getSym());
2203 for (const RangeSpan &Range : List.getRanges()) {
2204 const MCSymbol *Begin = Range.getStart();
2205 const MCSymbol *End = Range.getEnd();
2206 assert(Begin && "Range without a begin symbol?");
2207 assert(End && "Range without an end symbol?");
2208 if (TheCU->getRanges().size() == 1) {
2209 // Grab the begin symbol from the first range as our base.
2210 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2211 Asm->EmitLabelDifference(Begin, Base, Size);
2212 Asm->EmitLabelDifference(End, Base, Size);
2213 } else {
2214 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2215 Asm->OutStreamer.EmitSymbolValue(End, Size);
2216 }
2217 }
2219 // And terminate the list with two 0 values.
2220 Asm->OutStreamer.EmitIntValue(0, Size);
2221 Asm->OutStreamer.EmitIntValue(0, Size);
2222 }
2224 // Now emit a range for the CU itself.
2225 if (TheCU->getRanges().size() > 1) {
2226 Asm->OutStreamer.EmitLabel(
2227 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2228 for (const RangeSpan &Range : TheCU->getRanges()) {
2229 const MCSymbol *Begin = Range.getStart();
2230 const MCSymbol *End = Range.getEnd();
2231 assert(Begin && "Range without a begin symbol?");
2232 assert(End && "Range without an end symbol?");
2233 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2234 Asm->OutStreamer.EmitSymbolValue(End, Size);
2235 }
2236 // And terminate the list with two 0 values.
2237 Asm->OutStreamer.EmitIntValue(0, Size);
2238 Asm->OutStreamer.EmitIntValue(0, Size);
2239 }
2240 }
2241 }
2243 // DWARF5 Experimental Separate Dwarf emitters.
2245 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2246 std::unique_ptr<DwarfUnit> NewU) {
2247 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2248 U.getCUNode().getSplitDebugFilename());
2250 if (!CompilationDir.empty())
2251 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2253 addGnuPubAttributes(*NewU, Die);
2255 SkeletonHolder.addUnit(std::move(NewU));
2256 }
2258 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2259 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2260 // DW_AT_addr_base, DW_AT_ranges_base.
2261 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2263 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2264 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2265 DwarfCompileUnit &NewCU = *OwnedUnit;
2266 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2267 DwarfInfoSectionSym);
2269 NewCU.initStmtList(DwarfLineSectionSym);
2271 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2273 return NewCU;
2274 }
2276 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_dwo_name,
2277 // DW_AT_addr_base.
2278 DwarfTypeUnit &DwarfDebug::constructSkeletonTU(DwarfTypeUnit &TU) {
2279 DwarfCompileUnit &CU = static_cast<DwarfCompileUnit &>(
2280 *SkeletonHolder.getUnits()[TU.getCU().getUniqueID()]);
2282 auto OwnedUnit = make_unique<DwarfTypeUnit>(TU.getUniqueID(), CU, Asm, this,
2283 &SkeletonHolder);
2284 DwarfTypeUnit &NewTU = *OwnedUnit;
2285 NewTU.setTypeSignature(TU.getTypeSignature());
2286 NewTU.setType(nullptr);
2287 NewTU.initSection(
2288 Asm->getObjFileLowering().getDwarfTypesSection(TU.getTypeSignature()));
2290 initSkeletonUnit(TU, NewTU.getUnitDie(), std::move(OwnedUnit));
2291 return NewTU;
2292 }
2294 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2295 // compile units that would normally be in debug_info.
2296 void DwarfDebug::emitDebugInfoDWO() {
2297 assert(useSplitDwarf() && "No split dwarf debug info?");
2298 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2299 // emit relocations into the dwo file.
2300 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2301 }
2303 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2304 // abbreviations for the .debug_info.dwo section.
2305 void DwarfDebug::emitDebugAbbrevDWO() {
2306 assert(useSplitDwarf() && "No split dwarf?");
2307 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2308 }
2310 void DwarfDebug::emitDebugLineDWO() {
2311 assert(useSplitDwarf() && "No split dwarf?");
2312 Asm->OutStreamer.SwitchSection(
2313 Asm->getObjFileLowering().getDwarfLineDWOSection());
2314 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2315 }
2317 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2318 // string section and is identical in format to traditional .debug_str
2319 // sections.
2320 void DwarfDebug::emitDebugStrDWO() {
2321 assert(useSplitDwarf() && "No split dwarf?");
2322 const MCSection *OffSec =
2323 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2324 const MCSymbol *StrSym = DwarfStrSectionSym;
2325 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2326 OffSec, StrSym);
2327 }
2329 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2330 if (!useSplitDwarf())
2331 return nullptr;
2332 if (SingleCU)
2333 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2334 return &SplitTypeUnitFileTable;
2335 }
2337 static uint64_t makeTypeSignature(StringRef Identifier) {
2338 MD5 Hash;
2339 Hash.update(Identifier);
2340 // ... take the least significant 8 bytes and return those. Our MD5
2341 // implementation always returns its results in little endian, swap bytes
2342 // appropriately.
2343 MD5::MD5Result Result;
2344 Hash.final(Result);
2345 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2346 }
2348 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2349 StringRef Identifier, DIE &RefDie,
2350 DICompositeType CTy) {
2351 // Fast path if we're building some type units and one has already used the
2352 // address pool we know we're going to throw away all this work anyway, so
2353 // don't bother building dependent types.
2354 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2355 return;
2357 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2358 if (TU) {
2359 CU.addDIETypeSignature(RefDie, *TU);
2360 return;
2361 }
2363 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2364 AddrPool.resetUsedFlag();
2366 auto OwnedUnit =
2367 make_unique<DwarfTypeUnit>(InfoHolder.getUnits().size(), CU, Asm, this,
2368 &InfoHolder, getDwoLineTable(CU));
2369 DwarfTypeUnit &NewTU = *OwnedUnit;
2370 DIE &UnitDie = NewTU.getUnitDie();
2371 TU = &NewTU;
2372 TypeUnitsUnderConstruction.push_back(
2373 std::make_pair(std::move(OwnedUnit), CTy));
2375 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2376 CU.getLanguage());
2378 uint64_t Signature = makeTypeSignature(Identifier);
2379 NewTU.setTypeSignature(Signature);
2381 if (!useSplitDwarf())
2382 CU.applyStmtList(UnitDie);
2384 // FIXME: Skip using COMDAT groups for type units in the .dwo file once tools
2385 // such as DWP ( http://gcc.gnu.org/wiki/DebugFissionDWP ) can cope with it.
2386 NewTU.initSection(
2387 useSplitDwarf()
2388 ? Asm->getObjFileLowering().getDwarfTypesDWOSection(Signature)
2389 : Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2391 NewTU.setType(NewTU.createTypeDIE(CTy));
2393 if (TopLevelType) {
2394 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2395 TypeUnitsUnderConstruction.clear();
2397 // Types referencing entries in the address table cannot be placed in type
2398 // units.
2399 if (AddrPool.hasBeenUsed()) {
2401 // Remove all the types built while building this type.
2402 // This is pessimistic as some of these types might not be dependent on
2403 // the type that used an address.
2404 for (const auto &TU : TypeUnitsToAdd)
2405 DwarfTypeUnits.erase(TU.second);
2407 // Construct this type in the CU directly.
2408 // This is inefficient because all the dependent types will be rebuilt
2409 // from scratch, including building them in type units, discovering that
2410 // they depend on addresses, throwing them out and rebuilding them.
2411 CU.constructTypeDIE(RefDie, CTy);
2412 return;
2413 }
2415 // If the type wasn't dependent on fission addresses, finish adding the type
2416 // and all its dependent types.
2417 for (auto &TU : TypeUnitsToAdd) {
2418 if (useSplitDwarf())
2419 TU.first->setSkeleton(constructSkeletonTU(*TU.first));
2420 InfoHolder.addUnit(std::move(TU.first));
2421 }
2422 }
2423 CU.addDIETypeSignature(RefDie, NewTU);
2424 }
2426 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2427 MCSymbol *Begin, MCSymbol *End) {
2428 assert(Begin && "Begin label should not be null!");
2429 assert(End && "End label should not be null!");
2430 assert(Begin->isDefined() && "Invalid starting label");
2431 assert(End->isDefined() && "Invalid end label");
2433 Unit.addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
2434 if (DwarfVersion < 4)
2435 Unit.addLabelAddress(D, dwarf::DW_AT_high_pc, End);
2436 else
2437 Unit.addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
2438 }
2440 // Accelerator table mutators - add each name along with its companion
2441 // DIE to the proper table while ensuring that the name that we're going
2442 // to reference is in the string table. We do this since the names we
2443 // add may not only be identical to the names in the DIE.
2444 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2445 if (!useDwarfAccelTables())
2446 return;
2447 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2448 &Die);
2449 }
2451 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2452 if (!useDwarfAccelTables())
2453 return;
2454 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2455 &Die);
2456 }
2458 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2459 if (!useDwarfAccelTables())
2460 return;
2461 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2462 &Die);
2463 }
2465 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2466 if (!useDwarfAccelTables())
2467 return;
2468 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2469 &Die);
2470 }