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/Endian.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/FormattedStream.h"
42 #include "llvm/Support/LEB128.h"
43 #include "llvm/Support/MD5.h"
44 #include "llvm/Support/Path.h"
45 #include "llvm/Support/Timer.h"
46 #include "llvm/Target/TargetFrameLowering.h"
47 #include "llvm/Target/TargetLoweringObjectFile.h"
48 #include "llvm/Target/TargetMachine.h"
49 #include "llvm/Target/TargetOptions.h"
50 #include "llvm/Target/TargetRegisterInfo.h"
51 #include "llvm/Target/TargetSubtargetInfo.h"
52 using namespace llvm;
54 #define DEBUG_TYPE "dwarfdebug"
56 static cl::opt<bool>
57 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
58 cl::desc("Disable debug info printing"));
60 static cl::opt<bool> UnknownLocations(
61 "use-unknown-locations", cl::Hidden,
62 cl::desc("Make an absence of debug location information explicit."),
63 cl::init(false));
65 static cl::opt<bool>
66 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
67 cl::desc("Generate GNU-style pubnames and pubtypes"),
68 cl::init(false));
70 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
71 cl::Hidden,
72 cl::desc("Generate dwarf aranges"),
73 cl::init(false));
75 namespace {
76 enum DefaultOnOff { Default, Enable, Disable };
77 }
79 static cl::opt<DefaultOnOff>
80 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
81 cl::desc("Output prototype dwarf accelerator tables."),
82 cl::values(clEnumVal(Default, "Default for platform"),
83 clEnumVal(Enable, "Enabled"),
84 clEnumVal(Disable, "Disabled"), clEnumValEnd),
85 cl::init(Default));
87 static cl::opt<DefaultOnOff>
88 SplitDwarf("split-dwarf", cl::Hidden,
89 cl::desc("Output DWARF5 split debug info."),
90 cl::values(clEnumVal(Default, "Default for platform"),
91 clEnumVal(Enable, "Enabled"),
92 clEnumVal(Disable, "Disabled"), clEnumValEnd),
93 cl::init(Default));
95 static cl::opt<DefaultOnOff>
96 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
97 cl::desc("Generate DWARF pubnames and pubtypes sections"),
98 cl::values(clEnumVal(Default, "Default for platform"),
99 clEnumVal(Enable, "Enabled"),
100 clEnumVal(Disable, "Disabled"), clEnumValEnd),
101 cl::init(Default));
103 static const char *const DWARFGroupName = "DWARF Emission";
104 static const char *const DbgTimerName = "DWARF Debug Writer";
106 //===----------------------------------------------------------------------===//
108 /// resolve - Look in the DwarfDebug map for the MDNode that
109 /// corresponds to the reference.
110 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
111 return DD->resolve(Ref);
112 }
114 bool DbgVariable::isBlockByrefVariable() const {
115 assert(Var.isVariable() && "Invalid complex DbgVariable!");
116 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
117 }
119 DIType DbgVariable::getType() const {
120 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
121 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
122 // addresses instead.
123 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
124 /* Byref variables, in Blocks, are declared by the programmer as
125 "SomeType VarName;", but the compiler creates a
126 __Block_byref_x_VarName struct, and gives the variable VarName
127 either the struct, or a pointer to the struct, as its type. This
128 is necessary for various behind-the-scenes things the compiler
129 needs to do with by-reference variables in blocks.
131 However, as far as the original *programmer* is concerned, the
132 variable should still have type 'SomeType', as originally declared.
134 The following function dives into the __Block_byref_x_VarName
135 struct to find the original type of the variable. This will be
136 passed back to the code generating the type for the Debug
137 Information Entry for the variable 'VarName'. 'VarName' will then
138 have the original type 'SomeType' in its debug information.
140 The original type 'SomeType' will be the type of the field named
141 'VarName' inside the __Block_byref_x_VarName struct.
143 NOTE: In order for this to not completely fail on the debugger
144 side, the Debug Information Entry for the variable VarName needs to
145 have a DW_AT_location that tells the debugger how to unwind through
146 the pointers and __Block_byref_x_VarName struct to find the actual
147 value of the variable. The function addBlockByrefType does this. */
148 DIType subType = Ty;
149 uint16_t tag = Ty.getTag();
151 if (tag == dwarf::DW_TAG_pointer_type)
152 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
154 DIArray Elements = DICompositeType(subType).getElements();
155 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
156 DIDerivedType DT(Elements.getElement(i));
157 if (getName() == DT.getName())
158 return (resolve(DT.getTypeDerivedFrom()));
159 }
160 }
161 return Ty;
162 }
164 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
165 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
166 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
169 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
170 : Asm(A), MMI(Asm->MMI), FirstCU(nullptr), PrevLabel(nullptr),
171 GlobalRangeCount(0), InfoHolder(A, "info_string", DIEValueAllocator),
172 UsedNonDefaultText(false),
173 SkeletonHolder(A, "skel_string", DIEValueAllocator),
174 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
175 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
176 dwarf::DW_FORM_data4)),
177 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelTypes(TypeAtoms) {
183 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
184 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
185 DwarfLineSectionSym = nullptr;
186 DwarfAddrSectionSym = nullptr;
187 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
188 FunctionBeginSym = FunctionEndSym = nullptr;
189 CurFn = nullptr;
190 CurMI = nullptr;
192 // Turn on accelerator tables for Darwin by default, pubnames by
193 // default for non-Darwin, and handle split dwarf.
194 if (DwarfAccelTables == Default)
195 HasDwarfAccelTables = IsDarwin;
196 else
197 HasDwarfAccelTables = DwarfAccelTables == Enable;
199 if (SplitDwarf == Default)
200 HasSplitDwarf = false;
201 else
202 HasSplitDwarf = SplitDwarf == Enable;
204 if (DwarfPubSections == Default)
205 HasDwarfPubSections = !IsDarwin;
206 else
207 HasDwarfPubSections = DwarfPubSections == Enable;
209 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
210 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
211 : MMI->getModule()->getDwarfVersion();
213 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
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);
320 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
321 SPCU.addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
323 // Only include DW_AT_frame_base in full debug info
324 if (SPCU.getCUNode().getEmissionKind() != DIBuilder::LineTablesOnly) {
325 const TargetRegisterInfo *RI =
326 Asm->TM.getSubtargetImpl()->getRegisterInfo();
327 MachineLocation Location(RI->getFrameRegister(*Asm->MF));
328 SPCU.addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
329 }
331 // Add name to the name table, we do this here because we're guaranteed
332 // to have concrete versions of our DW_TAG_subprogram nodes.
333 addSubprogramNames(SP, *SPDie);
335 return *SPDie;
336 }
338 /// Check whether we should create a DIE for the given Scope, return true
339 /// if we don't create a DIE (the corresponding DIE is null).
340 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
341 if (Scope->isAbstractScope())
342 return false;
344 // We don't create a DIE if there is no Range.
345 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
346 if (Ranges.empty())
347 return true;
349 if (Ranges.size() > 1)
350 return false;
352 // We don't create a DIE if we have a single Range and the end label
353 // is null.
354 return !getLabelAfterInsn(Ranges.front().second);
355 }
357 static void addSectionLabel(AsmPrinter &Asm, DwarfUnit &U, DIE &D,
358 dwarf::Attribute A, const MCSymbol *L,
359 const MCSymbol *Sec) {
360 if (Asm.MAI->doesDwarfUseRelocationsAcrossSections())
361 U.addSectionLabel(D, A, L);
362 else
363 U.addSectionDelta(D, A, L, Sec);
364 }
366 void DwarfDebug::addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
367 const SmallVectorImpl<InsnRange> &Range) {
368 // Emit offset in .debug_range as a relocatable label. emitDIE will handle
369 // emitting it appropriately.
370 MCSymbol *RangeSym = Asm->GetTempSymbol("debug_ranges", GlobalRangeCount++);
372 // Under fission, ranges are specified by constant offsets relative to the
373 // CU's DW_AT_GNU_ranges_base.
374 if (useSplitDwarf())
375 TheCU.addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
376 DwarfDebugRangeSectionSym);
377 else
378 addSectionLabel(*Asm, TheCU, ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
379 DwarfDebugRangeSectionSym);
381 RangeSpanList List(RangeSym);
382 for (const InsnRange &R : Range) {
383 RangeSpan Span(getLabelBeforeInsn(R.first), getLabelAfterInsn(R.second));
384 List.addRange(std::move(Span));
385 }
387 // Add the range list to the set of ranges to be emitted.
388 TheCU.addRangeList(std::move(List));
389 }
391 void DwarfDebug::attachRangesOrLowHighPC(DwarfCompileUnit &TheCU, DIE &Die,
392 const SmallVectorImpl<InsnRange> &Ranges) {
393 assert(!Ranges.empty());
394 if (Ranges.size() == 1)
395 attachLowHighPC(TheCU, Die, getLabelBeforeInsn(Ranges.front().first),
396 getLabelAfterInsn(Ranges.front().second));
397 else
398 addScopeRangeList(TheCU, Die, Ranges);
399 }
401 // Construct new DW_TAG_lexical_block for this scope and attach
402 // DW_AT_low_pc/DW_AT_high_pc labels.
403 std::unique_ptr<DIE>
404 DwarfDebug::constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
405 LexicalScope *Scope) {
406 if (isLexicalScopeDIENull(Scope))
407 return nullptr;
409 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
410 if (Scope->isAbstractScope())
411 return ScopeDIE;
413 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
415 return ScopeDIE;
416 }
418 // This scope represents inlined body of a function. Construct DIE to
419 // represent this concrete inlined copy of the function.
420 std::unique_ptr<DIE>
421 DwarfDebug::constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
422 LexicalScope *Scope) {
423 assert(Scope->getScopeNode());
424 DIScope DS(Scope->getScopeNode());
425 DISubprogram InlinedSP = getDISubprogram(DS);
426 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
427 // was inlined from another compile unit.
428 DIE *OriginDIE = AbstractSPDies[InlinedSP];
429 assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
431 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
432 TheCU.addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
434 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
436 InlinedSubprogramDIEs.insert(OriginDIE);
438 // Add the call site information to the DIE.
439 DILocation DL(Scope->getInlinedAt());
440 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
441 TheCU.getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
442 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
444 // Add name to the name table, we do this here because we're guaranteed
445 // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
446 addSubprogramNames(InlinedSP, *ScopeDIE);
448 return ScopeDIE;
449 }
451 static std::unique_ptr<DIE> constructVariableDIE(DwarfCompileUnit &TheCU,
452 DbgVariable &DV,
453 const LexicalScope &Scope,
454 DIE *&ObjectPointer) {
455 auto Var = TheCU.constructVariableDIE(DV, Scope.isAbstractScope());
456 if (DV.isObjectPointer())
457 ObjectPointer = Var.get();
458 return Var;
459 }
461 DIE *DwarfDebug::createScopeChildrenDIE(
462 DwarfCompileUnit &TheCU, LexicalScope *Scope,
463 SmallVectorImpl<std::unique_ptr<DIE>> &Children,
464 unsigned *ChildScopeCount) {
465 DIE *ObjectPointer = nullptr;
467 for (DbgVariable *DV : ScopeVariables.lookup(Scope))
468 Children.push_back(constructVariableDIE(TheCU, *DV, *Scope, ObjectPointer));
470 unsigned ChildCountWithoutScopes = Children.size();
472 for (LexicalScope *LS : Scope->getChildren())
473 constructScopeDIE(TheCU, LS, Children);
475 if (ChildScopeCount)
476 *ChildScopeCount = Children.size() - ChildCountWithoutScopes;
478 return ObjectPointer;
479 }
481 DIE *DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU,
482 LexicalScope *Scope, DIE &ScopeDIE) {
483 // We create children when the scope DIE is not null.
484 SmallVector<std::unique_ptr<DIE>, 8> Children;
485 DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children);
487 // Add children
488 for (auto &I : Children)
489 ScopeDIE.addChild(std::move(I));
491 return ObjectPointer;
492 }
494 void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
495 LexicalScope *Scope) {
496 assert(Scope && Scope->getScopeNode());
497 assert(Scope->isAbstractScope());
498 assert(!Scope->getInlinedAt());
500 DISubprogram SP(Scope->getScopeNode());
502 ProcessedSPNodes.insert(SP);
504 DIE *&AbsDef = AbstractSPDies[SP];
505 if (AbsDef)
506 return;
508 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
509 // was inlined from another compile unit.
510 DwarfCompileUnit &SPCU = *SPMap[SP];
511 DIE *ContextDIE;
513 // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
514 // the important distinction that the DIDescriptor is not associated with the
515 // DIE (since the DIDescriptor will be associated with the concrete DIE, if
516 // any). It could be refactored to some common utility function.
517 if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
518 ContextDIE = &SPCU.getUnitDie();
519 SPCU.getOrCreateSubprogramDIE(SPDecl);
520 } else
521 ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
523 // Passing null as the associated DIDescriptor because the abstract definition
524 // shouldn't be found by lookup.
525 AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
526 DIDescriptor());
527 SPCU.applySubprogramAttributesToDefinition(SP, *AbsDef);
529 if (TheCU.getCUNode().getEmissionKind() != DIBuilder::LineTablesOnly)
530 SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
531 if (DIE *ObjectPointer = createAndAddScopeChildren(SPCU, Scope, *AbsDef))
532 SPCU.addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
533 }
535 void DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
536 LexicalScope *Scope) {
537 assert(Scope && Scope->getScopeNode());
538 assert(!Scope->getInlinedAt());
539 assert(!Scope->isAbstractScope());
540 DISubprogram Sub(Scope->getScopeNode());
542 assert(Sub.isSubprogram());
544 ProcessedSPNodes.insert(Sub);
546 DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub);
548 // Collect arguments for current function.
549 assert(LScopes.isCurrentFunctionScope(Scope));
550 DIE *ObjectPointer = nullptr;
551 for (DbgVariable *ArgDV : CurrentFnArguments)
552 if (ArgDV)
553 ScopeDIE.addChild(
554 constructVariableDIE(TheCU, *ArgDV, *Scope, ObjectPointer));
556 // If this is a variadic function, add an unspecified parameter.
557 DITypeArray FnArgs = Sub.getType().getTypeArray();
558 // If we have a single element of null, it is a function that returns void.
559 // If we have more than one elements and the last one is null, it is a
560 // variadic function.
561 if (FnArgs.getNumElements() > 1 &&
562 !FnArgs.getElement(FnArgs.getNumElements() - 1))
563 ScopeDIE.addChild(make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
565 // Collect lexical scope children first.
566 // ObjectPointer might be a local (non-argument) local variable if it's a
567 // block's synthetic this pointer.
568 if (DIE *BlockObjPtr = createAndAddScopeChildren(TheCU, Scope, ScopeDIE)) {
569 assert(!ObjectPointer && "multiple object pointers can't be described");
570 ObjectPointer = BlockObjPtr;
571 }
573 if (ObjectPointer)
574 TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
575 }
577 // Construct a DIE for this scope.
578 void DwarfDebug::constructScopeDIE(
579 DwarfCompileUnit &TheCU, LexicalScope *Scope,
580 SmallVectorImpl<std::unique_ptr<DIE>> &FinalChildren) {
581 if (!Scope || !Scope->getScopeNode())
582 return;
584 DIScope DS(Scope->getScopeNode());
586 assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
587 "Only handle inlined subprograms here, use "
588 "constructSubprogramScopeDIE for non-inlined "
589 "subprograms");
591 SmallVector<std::unique_ptr<DIE>, 8> Children;
593 // We try to create the scope DIE first, then the children DIEs. This will
594 // avoid creating un-used children then removing them later when we find out
595 // the scope DIE is null.
596 std::unique_ptr<DIE> ScopeDIE;
597 if (Scope->getParent() && DS.isSubprogram()) {
598 ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
599 if (!ScopeDIE)
600 return;
601 // We create children when the scope DIE is not null.
602 createScopeChildrenDIE(TheCU, Scope, Children);
603 } else {
604 // Early exit when we know the scope DIE is going to be null.
605 if (isLexicalScopeDIENull(Scope))
606 return;
608 unsigned ChildScopeCount;
610 // We create children here when we know the scope DIE is not going to be
611 // null and the children will be added to the scope DIE.
612 createScopeChildrenDIE(TheCU, Scope, Children, &ChildScopeCount);
614 // There is no need to emit empty lexical block DIE.
615 std::pair<ImportedEntityMap::const_iterator,
616 ImportedEntityMap::const_iterator> Range =
617 std::equal_range(ScopesWithImportedEntities.begin(),
618 ScopesWithImportedEntities.end(),
619 std::pair<const MDNode *, const MDNode *>(DS, nullptr),
620 less_first());
621 for (ImportedEntityMap::const_iterator i = Range.first; i != Range.second;
622 ++i)
623 Children.push_back(
624 constructImportedEntityDIE(TheCU, DIImportedEntity(i->second)));
625 // If there are only other scopes as children, put them directly in the
626 // parent instead, as this scope would serve no purpose.
627 if (Children.size() == ChildScopeCount) {
628 FinalChildren.insert(FinalChildren.end(),
629 std::make_move_iterator(Children.begin()),
630 std::make_move_iterator(Children.end()));
631 return;
632 }
633 ScopeDIE = constructLexicalScopeDIE(TheCU, Scope);
634 assert(ScopeDIE && "Scope DIE should not be null.");
635 }
637 // Add children
638 for (auto &I : Children)
639 ScopeDIE->addChild(std::move(I));
641 FinalChildren.push_back(std::move(ScopeDIE));
642 }
644 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
645 if (!GenerateGnuPubSections)
646 return;
648 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
649 }
651 // Create new DwarfCompileUnit for the given metadata node with tag
652 // DW_TAG_compile_unit.
653 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
654 StringRef FN = DIUnit.getFilename();
655 CompilationDir = DIUnit.getDirectory();
657 auto OwnedUnit = make_unique<DwarfCompileUnit>(
658 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
659 DwarfCompileUnit &NewCU = *OwnedUnit;
660 DIE &Die = NewCU.getUnitDie();
661 InfoHolder.addUnit(std::move(OwnedUnit));
663 // LTO with assembly output shares a single line table amongst multiple CUs.
664 // To avoid the compilation directory being ambiguous, let the line table
665 // explicitly describe the directory of all files, never relying on the
666 // compilation directory.
667 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
668 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
669 NewCU.getUniqueID(), CompilationDir);
671 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
672 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
673 DIUnit.getLanguage());
674 NewCU.addString(Die, dwarf::DW_AT_name, FN);
676 if (!useSplitDwarf()) {
677 NewCU.initStmtList(DwarfLineSectionSym);
679 // If we're using split dwarf the compilation dir is going to be in the
680 // skeleton CU and so we don't need to duplicate it here.
681 if (!CompilationDir.empty())
682 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
684 addGnuPubAttributes(NewCU, Die);
685 }
687 if (DIUnit.isOptimized())
688 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
690 StringRef Flags = DIUnit.getFlags();
691 if (!Flags.empty())
692 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
694 if (unsigned RVer = DIUnit.getRunTimeVersion())
695 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
696 dwarf::DW_FORM_data1, RVer);
698 if (!FirstCU)
699 FirstCU = &NewCU;
701 if (useSplitDwarf()) {
702 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
703 DwarfInfoDWOSectionSym);
704 NewCU.setSkeleton(constructSkeletonCU(NewCU));
705 } else
706 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
707 DwarfInfoSectionSym);
709 CUMap.insert(std::make_pair(DIUnit, &NewCU));
710 CUDieMap.insert(std::make_pair(&Die, &NewCU));
711 return NewCU;
712 }
714 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
715 const MDNode *N) {
716 DIImportedEntity Module(N);
717 assert(Module.Verify());
718 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
719 D->addChild(constructImportedEntityDIE(TheCU, Module));
720 }
722 std::unique_ptr<DIE>
723 DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
724 const DIImportedEntity &Module) {
725 assert(Module.Verify() &&
726 "Use one of the MDNode * overloads to handle invalid metadata");
727 std::unique_ptr<DIE> IMDie = make_unique<DIE>((dwarf::Tag)Module.getTag());
728 TheCU.insertDIE(Module, IMDie.get());
729 DIE *EntityDie;
730 DIDescriptor Entity = resolve(Module.getEntity());
731 if (Entity.isNameSpace())
732 EntityDie = TheCU.getOrCreateNameSpace(DINameSpace(Entity));
733 else if (Entity.isSubprogram())
734 EntityDie = TheCU.getOrCreateSubprogramDIE(DISubprogram(Entity));
735 else if (Entity.isType())
736 EntityDie = TheCU.getOrCreateTypeDIE(DIType(Entity));
737 else
738 EntityDie = TheCU.getDIE(Entity);
739 assert(EntityDie);
740 TheCU.addSourceLine(*IMDie, Module.getLineNumber(),
741 Module.getContext().getFilename(),
742 Module.getContext().getDirectory());
743 TheCU.addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
744 StringRef Name = Module.getName();
745 if (!Name.empty())
746 TheCU.addString(*IMDie, dwarf::DW_AT_name, Name);
748 return IMDie;
749 }
751 // Emit all Dwarf sections that should come prior to the content. Create
752 // global DIEs and emit initial debug info sections. This is invoked by
753 // the target AsmPrinter.
754 void DwarfDebug::beginModule() {
755 if (DisableDebugInfoPrinting)
756 return;
758 const Module *M = MMI->getModule();
760 FunctionDIs = makeSubprogramMap(*M);
762 // If module has named metadata anchors then use them, otherwise scan the
763 // module using debug info finder to collect debug info.
764 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
765 if (!CU_Nodes)
766 return;
767 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
769 // Emit initial sections so we can reference labels later.
770 emitSectionLabels();
772 SingleCU = CU_Nodes->getNumOperands() == 1;
774 for (MDNode *N : CU_Nodes->operands()) {
775 DICompileUnit CUNode(N);
776 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
777 DIArray ImportedEntities = CUNode.getImportedEntities();
778 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
779 ScopesWithImportedEntities.push_back(std::make_pair(
780 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
781 ImportedEntities.getElement(i)));
782 std::sort(ScopesWithImportedEntities.begin(),
783 ScopesWithImportedEntities.end(), less_first());
784 DIArray GVs = CUNode.getGlobalVariables();
785 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
786 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
787 DIArray SPs = CUNode.getSubprograms();
788 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
789 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
790 DIArray EnumTypes = CUNode.getEnumTypes();
791 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
792 DIType Ty(EnumTypes.getElement(i));
793 // The enum types array by design contains pointers to
794 // MDNodes rather than DIRefs. Unique them here.
795 DIType UniqueTy(resolve(Ty.getRef()));
796 CU.getOrCreateTypeDIE(UniqueTy);
797 }
798 DIArray RetainedTypes = CUNode.getRetainedTypes();
799 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
800 DIType Ty(RetainedTypes.getElement(i));
801 // The retained types array by design contains pointers to
802 // MDNodes rather than DIRefs. Unique them here.
803 DIType UniqueTy(resolve(Ty.getRef()));
804 CU.getOrCreateTypeDIE(UniqueTy);
805 }
806 // Emit imported_modules last so that the relevant context is already
807 // available.
808 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
809 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
810 }
812 // Tell MMI that we have debug info.
813 MMI->setDebugInfoAvailability(true);
815 // Prime section data.
816 SectionMap[Asm->getObjFileLowering().getTextSection()];
817 }
819 void DwarfDebug::finishVariableDefinitions() {
820 for (const auto &Var : ConcreteVariables) {
821 DIE *VariableDie = Var->getDIE();
822 assert(VariableDie);
823 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
824 // in the ConcreteVariables list, rather than looking it up again here.
825 // DIE::getUnit isn't simple - it walks parent pointers, etc.
826 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
827 assert(Unit);
828 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
829 if (AbsVar && AbsVar->getDIE()) {
830 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
831 *AbsVar->getDIE());
832 } else
833 Unit->applyVariableAttributes(*Var, *VariableDie);
834 }
835 }
837 void DwarfDebug::finishSubprogramDefinitions() {
838 const Module *M = MMI->getModule();
840 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
841 for (MDNode *N : CU_Nodes->operands()) {
842 DICompileUnit TheCU(N);
843 // Construct subprogram DIE and add variables DIEs.
844 DwarfCompileUnit *SPCU =
845 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
846 DIArray Subprograms = TheCU.getSubprograms();
847 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
848 DISubprogram SP(Subprograms.getElement(i));
849 // Perhaps the subprogram is in another CU (such as due to comdat
850 // folding, etc), in which case ignore it here.
851 if (SPMap[SP] != SPCU)
852 continue;
853 DIE *D = SPCU->getDIE(SP);
854 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
855 if (D)
856 // If this subprogram has an abstract definition, reference that
857 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
858 } else {
859 if (!D && TheCU.getEmissionKind() != DIBuilder::LineTablesOnly)
860 // Lazily construct the subprogram if we didn't see either concrete or
861 // inlined versions during codegen. (except in -gmlt ^ where we want
862 // to omit these entirely)
863 D = SPCU->getOrCreateSubprogramDIE(SP);
864 if (D)
865 // And attach the attributes
866 SPCU->applySubprogramAttributesToDefinition(SP, *D);
867 }
868 }
869 }
870 }
873 // Collect info for variables that were optimized out.
874 void DwarfDebug::collectDeadVariables() {
875 const Module *M = MMI->getModule();
877 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
878 for (MDNode *N : CU_Nodes->operands()) {
879 DICompileUnit TheCU(N);
880 // Construct subprogram DIE and add variables DIEs.
881 DwarfCompileUnit *SPCU =
882 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
883 assert(SPCU && "Unable to find Compile Unit!");
884 DIArray Subprograms = TheCU.getSubprograms();
885 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
886 DISubprogram SP(Subprograms.getElement(i));
887 if (ProcessedSPNodes.count(SP) != 0)
888 continue;
889 assert(SP.isSubprogram() &&
890 "CU's subprogram list contains a non-subprogram");
891 assert(SP.isDefinition() &&
892 "CU's subprogram list contains a subprogram declaration");
893 DIArray Variables = SP.getVariables();
894 if (Variables.getNumElements() == 0)
895 continue;
897 DIE *SPDIE = AbstractSPDies.lookup(SP);
898 if (!SPDIE)
899 SPDIE = SPCU->getDIE(SP);
900 assert(SPDIE);
901 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
902 DIVariable DV(Variables.getElement(vi));
903 assert(DV.isVariable());
904 DbgVariable NewVar(DV, this);
905 auto VariableDie = SPCU->constructVariableDIE(NewVar);
906 SPCU->applyVariableAttributes(NewVar, *VariableDie);
907 SPDIE->addChild(std::move(VariableDie));
908 }
909 }
910 }
911 }
912 }
914 void DwarfDebug::finalizeModuleInfo() {
915 finishSubprogramDefinitions();
917 finishVariableDefinitions();
919 // Collect info for variables that were optimized out.
920 collectDeadVariables();
922 // Handle anything that needs to be done on a per-unit basis after
923 // all other generation.
924 for (const auto &TheU : getUnits()) {
925 // Emit DW_AT_containing_type attribute to connect types with their
926 // vtable holding type.
927 TheU->constructContainingTypeDIEs();
929 // Add CU specific attributes if we need to add any.
930 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
931 // If we're splitting the dwarf out now that we've got the entire
932 // CU then add the dwo id to it.
933 DwarfCompileUnit *SkCU =
934 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
935 if (useSplitDwarf()) {
936 // Emit a unique identifier for this CU.
937 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
938 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
939 dwarf::DW_FORM_data8, ID);
940 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
941 dwarf::DW_FORM_data8, ID);
943 // We don't keep track of which addresses are used in which CU so this
944 // is a bit pessimistic under LTO.
945 if (!AddrPool.isEmpty())
946 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
947 dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
948 DwarfAddrSectionSym);
949 if (!TheU->getRangeLists().empty())
950 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
951 dwarf::DW_AT_GNU_ranges_base,
952 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
953 }
955 // If we have code split among multiple sections or non-contiguous
956 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
957 // remain in the .o file, otherwise add a DW_AT_low_pc.
958 // FIXME: We should use ranges allow reordering of code ala
959 // .subsections_via_symbols in mach-o. This would mean turning on
960 // ranges for all subprogram DIEs for mach-o.
961 DwarfCompileUnit &U =
962 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
963 unsigned NumRanges = TheU->getRanges().size();
964 if (NumRanges) {
965 if (NumRanges > 1) {
966 addSectionLabel(*Asm, U, U.getUnitDie(), dwarf::DW_AT_ranges,
967 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
968 DwarfDebugRangeSectionSym);
970 // A DW_AT_low_pc attribute may also be specified in combination with
971 // DW_AT_ranges to specify the default base address for use in
972 // location lists (see Section 2.6.2) and range lists (see Section
973 // 2.17.3).
974 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
975 0);
976 } else {
977 RangeSpan &Range = TheU->getRanges().back();
978 attachLowHighPC(U, U.getUnitDie(), Range.getStart(), Range.getEnd());
979 }
980 }
981 }
982 }
984 // Compute DIE offsets and sizes.
985 InfoHolder.computeSizeAndOffsets();
986 if (useSplitDwarf())
987 SkeletonHolder.computeSizeAndOffsets();
988 }
990 void DwarfDebug::endSections() {
991 // Filter labels by section.
992 for (const SymbolCU &SCU : ArangeLabels) {
993 if (SCU.Sym->isInSection()) {
994 // Make a note of this symbol and it's section.
995 const MCSection *Section = &SCU.Sym->getSection();
996 if (!Section->getKind().isMetadata())
997 SectionMap[Section].push_back(SCU);
998 } else {
999 // Some symbols (e.g. common/bss on mach-o) can have no section but still
1000 // appear in the output. This sucks as we rely on sections to build
1001 // arange spans. We can do it without, but it's icky.
1002 SectionMap[nullptr].push_back(SCU);
1003 }
1004 }
1006 // Build a list of sections used.
1007 std::vector<const MCSection *> Sections;
1008 for (const auto &it : SectionMap) {
1009 const MCSection *Section = it.first;
1010 Sections.push_back(Section);
1011 }
1013 // Sort the sections into order.
1014 // This is only done to ensure consistent output order across different runs.
1015 std::sort(Sections.begin(), Sections.end(), SectionSort);
1017 // Add terminating symbols for each section.
1018 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
1019 const MCSection *Section = Sections[ID];
1020 MCSymbol *Sym = nullptr;
1022 if (Section) {
1023 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1024 // if we know the section name up-front. For user-created sections, the
1025 // resulting label may not be valid to use as a label. (section names can
1026 // use a greater set of characters on some systems)
1027 Sym = Asm->GetTempSymbol("debug_end", ID);
1028 Asm->OutStreamer.SwitchSection(Section);
1029 Asm->OutStreamer.EmitLabel(Sym);
1030 }
1032 // Insert a final terminator.
1033 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1034 }
1035 }
1037 // Emit all Dwarf sections that should come after the content.
1038 void DwarfDebug::endModule() {
1039 assert(CurFn == nullptr);
1040 assert(CurMI == nullptr);
1042 if (!FirstCU)
1043 return;
1045 // End any existing sections.
1046 // TODO: Does this need to happen?
1047 endSections();
1049 // Finalize the debug info for the module.
1050 finalizeModuleInfo();
1052 emitDebugStr();
1054 // Emit all the DIEs into a debug info section.
1055 emitDebugInfo();
1057 // Corresponding abbreviations into a abbrev section.
1058 emitAbbreviations();
1060 // Emit info into a debug aranges section.
1061 if (GenerateARangeSection)
1062 emitDebugARanges();
1064 // Emit info into a debug ranges section.
1065 emitDebugRanges();
1067 if (useSplitDwarf()) {
1068 emitDebugStrDWO();
1069 emitDebugInfoDWO();
1070 emitDebugAbbrevDWO();
1071 emitDebugLineDWO();
1072 emitDebugLocDWO();
1073 // Emit DWO addresses.
1074 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
1075 } else
1076 // Emit info into a debug loc section.
1077 emitDebugLoc();
1079 // Emit info into the dwarf accelerator table sections.
1080 if (useDwarfAccelTables()) {
1081 emitAccelNames();
1082 emitAccelObjC();
1083 emitAccelNamespaces();
1084 emitAccelTypes();
1085 }
1087 // Emit the pubnames and pubtypes sections if requested.
1088 if (HasDwarfPubSections) {
1089 emitDebugPubNames(GenerateGnuPubSections);
1090 emitDebugPubTypes(GenerateGnuPubSections);
1091 }
1093 // clean up.
1094 SPMap.clear();
1095 AbstractVariables.clear();
1097 // Reset these for the next Module if we have one.
1098 FirstCU = nullptr;
1099 }
1101 // Find abstract variable, if any, associated with Var.
1102 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
1103 DIVariable &Cleansed) {
1104 LLVMContext &Ctx = DV->getContext();
1105 // More then one inlined variable corresponds to one abstract variable.
1106 // FIXME: This duplication of variables when inlining should probably be
1107 // removed. It's done to allow each DIVariable to describe its location
1108 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
1109 // make it accurate then remove this duplication/cleansing stuff.
1110 Cleansed = cleanseInlinedVariable(DV, Ctx);
1111 auto I = AbstractVariables.find(Cleansed);
1112 if (I != AbstractVariables.end())
1113 return I->second.get();
1114 return nullptr;
1115 }
1117 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
1118 DIVariable Cleansed;
1119 return getExistingAbstractVariable(DV, Cleansed);
1120 }
1122 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
1123 LexicalScope *Scope) {
1124 auto AbsDbgVariable = make_unique<DbgVariable>(Var, this);
1125 addScopeVariable(Scope, AbsDbgVariable.get());
1126 AbstractVariables[Var] = std::move(AbsDbgVariable);
1127 }
1129 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
1130 const MDNode *ScopeNode) {
1131 DIVariable Cleansed = DV;
1132 if (getExistingAbstractVariable(DV, Cleansed))
1133 return;
1135 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
1136 }
1138 void
1139 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
1140 const MDNode *ScopeNode) {
1141 DIVariable Cleansed = DV;
1142 if (getExistingAbstractVariable(DV, Cleansed))
1143 return;
1145 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
1146 createAbstractVariable(Cleansed, Scope);
1147 }
1149 // If Var is a current function argument then add it to CurrentFnArguments list.
1150 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
1151 if (!LScopes.isCurrentFunctionScope(Scope))
1152 return false;
1153 DIVariable DV = Var->getVariable();
1154 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
1155 return false;
1156 unsigned ArgNo = DV.getArgNumber();
1157 if (ArgNo == 0)
1158 return false;
1160 size_t Size = CurrentFnArguments.size();
1161 if (Size == 0)
1162 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
1163 // llvm::Function argument size is not good indicator of how many
1164 // arguments does the function have at source level.
1165 if (ArgNo > Size)
1166 CurrentFnArguments.resize(ArgNo * 2);
1167 assert(!CurrentFnArguments[ArgNo - 1]);
1168 CurrentFnArguments[ArgNo - 1] = Var;
1169 return true;
1170 }
1172 // Collect variable information from side table maintained by MMI.
1173 void DwarfDebug::collectVariableInfoFromMMITable(
1174 SmallPtrSetImpl<const MDNode *> &Processed) {
1175 for (const auto &VI : MMI->getVariableDbgInfo()) {
1176 if (!VI.Var)
1177 continue;
1178 Processed.insert(VI.Var);
1179 DIVariable DV(VI.Var);
1180 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
1182 // If variable scope is not found then skip this variable.
1183 if (!Scope)
1184 continue;
1186 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1187 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
1188 DbgVariable *RegVar = ConcreteVariables.back().get();
1189 RegVar->setFrameIndex(VI.Slot);
1190 addScopeVariable(Scope, RegVar);
1191 }
1192 }
1194 // Get .debug_loc entry for the instruction range starting at MI.
1195 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
1196 const MDNode *Var = MI->getDebugVariable();
1198 assert(MI->getNumOperands() == 3);
1199 if (MI->getOperand(0).isReg()) {
1200 MachineLocation MLoc;
1201 // If the second operand is an immediate, this is a
1202 // register-indirect address.
1203 if (!MI->getOperand(1).isImm())
1204 MLoc.set(MI->getOperand(0).getReg());
1205 else
1206 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
1207 return DebugLocEntry::Value(Var, MLoc);
1208 }
1209 if (MI->getOperand(0).isImm())
1210 return DebugLocEntry::Value(Var, MI->getOperand(0).getImm());
1211 if (MI->getOperand(0).isFPImm())
1212 return DebugLocEntry::Value(Var, MI->getOperand(0).getFPImm());
1213 if (MI->getOperand(0).isCImm())
1214 return DebugLocEntry::Value(Var, MI->getOperand(0).getCImm());
1216 llvm_unreachable("Unexpected 3 operand DBG_VALUE instruction!");
1217 }
1219 /// Determine whether two variable pieces overlap.
1220 static bool piecesOverlap(DIVariable P1, DIVariable P2) {
1221 if (!P1.isVariablePiece() || !P2.isVariablePiece())
1222 return true;
1223 unsigned l1 = P1.getPieceOffset();
1224 unsigned l2 = P2.getPieceOffset();
1225 unsigned r1 = l1 + P1.getPieceSize();
1226 unsigned r2 = l2 + P2.getPieceSize();
1227 // True where [l1,r1[ and [r1,r2[ overlap.
1228 return (l1 < r2) && (l2 < r1);
1229 }
1231 /// Build the location list for all DBG_VALUEs in the function that
1232 /// describe the same variable. If the ranges of several independent
1233 /// pieces of the same variable overlap partially, split them up and
1234 /// combine the ranges. The resulting DebugLocEntries are will have
1235 /// strict monotonically increasing begin addresses and will never
1236 /// overlap.
1237 //
1238 // Input:
1239 //
1240 // Ranges History [var, loc, piece ofs size]
1241 // 0 | [x, (reg0, piece 0, 32)]
1242 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
1243 // 2 | | ...
1244 // 3 | [clobber reg0]
1245 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
1246 //
1247 // Output:
1248 //
1249 // [0-1] [x, (reg0, piece 0, 32)]
1250 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
1251 // [3-4] [x, (reg1, piece 32, 32)]
1252 // [4- ] [x, (mem, piece 0, 64)]
1253 void
1254 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
1255 const DbgValueHistoryMap::InstrRanges &Ranges) {
1256 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
1258 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1259 const MachineInstr *Begin = I->first;
1260 const MachineInstr *End = I->second;
1261 assert(Begin->isDebugValue() && "Invalid History entry");
1263 // Check if a variable is inaccessible in this range.
1264 if (Begin->getNumOperands() > 1 &&
1265 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
1266 OpenRanges.clear();
1267 continue;
1268 }
1270 // If this piece overlaps with any open ranges, truncate them.
1271 DIVariable DIVar = Begin->getDebugVariable();
1272 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
1273 [&](DebugLocEntry::Value R) {
1274 return piecesOverlap(DIVar, R.getVariable());
1275 });
1276 OpenRanges.erase(Last, OpenRanges.end());
1278 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
1279 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
1281 const MCSymbol *EndLabel;
1282 if (End != nullptr)
1283 EndLabel = getLabelAfterInsn(End);
1284 else if (std::next(I) == Ranges.end())
1285 EndLabel = FunctionEndSym;
1286 else
1287 EndLabel = getLabelBeforeInsn(std::next(I)->first);
1288 assert(EndLabel && "Forgot label after instruction ending a range!");
1290 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
1292 auto Value = getDebugLocValue(Begin);
1293 DebugLocEntry Loc(StartLabel, EndLabel, Value);
1294 bool couldMerge = false;
1296 // If this is a piece, it may belong to the current DebugLocEntry.
1297 if (DIVar.isVariablePiece()) {
1298 // Add this value to the list of open ranges.
1299 OpenRanges.push_back(Value);
1301 // Attempt to add the piece to the last entry.
1302 if (!DebugLoc.empty())
1303 if (DebugLoc.back().MergeValues(Loc))
1304 couldMerge = true;
1305 }
1307 if (!couldMerge) {
1308 // Need to add a new DebugLocEntry. Add all values from still
1309 // valid non-overlapping pieces.
1310 if (OpenRanges.size())
1311 Loc.addValues(OpenRanges);
1313 DebugLoc.push_back(std::move(Loc));
1314 }
1316 // Attempt to coalesce the ranges of two otherwise identical
1317 // DebugLocEntries.
1318 auto CurEntry = DebugLoc.rbegin();
1319 auto PrevEntry = std::next(CurEntry);
1320 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
1321 DebugLoc.pop_back();
1323 DEBUG(dbgs() << "Values:\n";
1324 for (auto Value : CurEntry->getValues())
1325 Value.getVariable()->dump();
1326 dbgs() << "-----\n");
1327 }
1328 }
1331 // Find variables for each lexical scope.
1332 void
1333 DwarfDebug::collectVariableInfo(SmallPtrSetImpl<const MDNode *> &Processed) {
1334 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1335 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1337 // Grab the variable info that was squirreled away in the MMI side-table.
1338 collectVariableInfoFromMMITable(Processed);
1340 for (const auto &I : DbgValues) {
1341 DIVariable DV(I.first);
1342 if (Processed.count(DV))
1343 continue;
1345 // Instruction ranges, specifying where DV is accessible.
1346 const auto &Ranges = I.second;
1347 if (Ranges.empty())
1348 continue;
1350 LexicalScope *Scope = nullptr;
1351 if (MDNode *IA = DV.getInlinedAt()) {
1352 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1353 Scope = LScopes.findInlinedScope(DebugLoc::get(
1354 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1355 } else
1356 Scope = LScopes.findLexicalScope(DV.getContext());
1357 // If variable scope is not found then skip this variable.
1358 if (!Scope)
1359 continue;
1361 Processed.insert(getEntireVariable(DV));
1362 const MachineInstr *MInsn = Ranges.front().first;
1363 assert(MInsn->isDebugValue() && "History must begin with debug value");
1364 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1365 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
1366 DbgVariable *RegVar = ConcreteVariables.back().get();
1367 addScopeVariable(Scope, RegVar);
1369 // Check if the first DBG_VALUE is valid for the rest of the function.
1370 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1371 continue;
1373 // Handle multiple DBG_VALUE instructions describing one variable.
1374 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1376 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1377 DebugLocList &LocList = DotDebugLocEntries.back();
1378 LocList.CU = TheCU;
1379 LocList.Label =
1380 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1382 // Build the location list for this variable.
1383 buildLocationList(LocList.List, Ranges);
1384 }
1386 // Collect info for variables that were optimized out.
1387 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1388 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1389 DIVariable DV(Variables.getElement(i));
1390 assert(DV.isVariable());
1391 if (!Processed.insert(DV))
1392 continue;
1393 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1394 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1395 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
1396 addScopeVariable(Scope, ConcreteVariables.back().get());
1397 }
1398 }
1399 }
1401 // Return Label preceding the instruction.
1402 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1403 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1404 assert(Label && "Didn't insert label before instruction");
1405 return Label;
1406 }
1408 // Return Label immediately following the instruction.
1409 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1410 return LabelsAfterInsn.lookup(MI);
1411 }
1413 // Process beginning of an instruction.
1414 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1415 assert(CurMI == nullptr);
1416 CurMI = MI;
1417 // Check if source location changes, but ignore DBG_VALUE locations.
1418 if (!MI->isDebugValue()) {
1419 DebugLoc DL = MI->getDebugLoc();
1420 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1421 unsigned Flags = 0;
1422 PrevInstLoc = DL;
1423 if (DL == PrologEndLoc) {
1424 Flags |= DWARF2_FLAG_PROLOGUE_END;
1425 PrologEndLoc = DebugLoc();
1426 }
1427 if (PrologEndLoc.isUnknown())
1428 Flags |= DWARF2_FLAG_IS_STMT;
1430 if (!DL.isUnknown()) {
1431 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1432 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1433 } else
1434 recordSourceLine(0, 0, nullptr, 0);
1435 }
1436 }
1438 // Insert labels where requested.
1439 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1440 LabelsBeforeInsn.find(MI);
1442 // No label needed.
1443 if (I == LabelsBeforeInsn.end())
1444 return;
1446 // Label already assigned.
1447 if (I->second)
1448 return;
1450 if (!PrevLabel) {
1451 PrevLabel = MMI->getContext().CreateTempSymbol();
1452 Asm->OutStreamer.EmitLabel(PrevLabel);
1453 }
1454 I->second = PrevLabel;
1455 }
1457 // Process end of an instruction.
1458 void DwarfDebug::endInstruction() {
1459 assert(CurMI != nullptr);
1460 // Don't create a new label after DBG_VALUE instructions.
1461 // They don't generate code.
1462 if (!CurMI->isDebugValue())
1463 PrevLabel = nullptr;
1465 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1466 LabelsAfterInsn.find(CurMI);
1467 CurMI = nullptr;
1469 // No label needed.
1470 if (I == LabelsAfterInsn.end())
1471 return;
1473 // Label already assigned.
1474 if (I->second)
1475 return;
1477 // We need a label after this instruction.
1478 if (!PrevLabel) {
1479 PrevLabel = MMI->getContext().CreateTempSymbol();
1480 Asm->OutStreamer.EmitLabel(PrevLabel);
1481 }
1482 I->second = PrevLabel;
1483 }
1485 // Each LexicalScope has first instruction and last instruction to mark
1486 // beginning and end of a scope respectively. Create an inverse map that list
1487 // scopes starts (and ends) with an instruction. One instruction may start (or
1488 // end) multiple scopes. Ignore scopes that are not reachable.
1489 void DwarfDebug::identifyScopeMarkers() {
1490 SmallVector<LexicalScope *, 4> WorkList;
1491 WorkList.push_back(LScopes.getCurrentFunctionScope());
1492 while (!WorkList.empty()) {
1493 LexicalScope *S = WorkList.pop_back_val();
1495 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1496 if (!Children.empty())
1497 WorkList.append(Children.begin(), Children.end());
1499 if (S->isAbstractScope())
1500 continue;
1502 for (const InsnRange &R : S->getRanges()) {
1503 assert(R.first && "InsnRange does not have first instruction!");
1504 assert(R.second && "InsnRange does not have second instruction!");
1505 requestLabelBeforeInsn(R.first);
1506 requestLabelAfterInsn(R.second);
1507 }
1508 }
1509 }
1511 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1512 // First known non-DBG_VALUE and non-frame setup location marks
1513 // the beginning of the function body.
1514 for (const auto &MBB : *MF)
1515 for (const auto &MI : MBB)
1516 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1517 !MI.getDebugLoc().isUnknown())
1518 return MI.getDebugLoc();
1519 return DebugLoc();
1520 }
1522 // Gather pre-function debug information. Assumes being called immediately
1523 // after the function entry point has been emitted.
1524 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1525 CurFn = MF;
1527 // If there's no debug info for the function we're not going to do anything.
1528 if (!MMI->hasDebugInfo())
1529 return;
1531 auto DI = FunctionDIs.find(MF->getFunction());
1532 if (DI == FunctionDIs.end())
1533 return;
1535 // Grab the lexical scopes for the function, if we don't have any of those
1536 // then we're not going to be able to do anything.
1537 LScopes.initialize(*MF);
1538 if (LScopes.empty())
1539 return;
1541 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1543 // Make sure that each lexical scope will have a begin/end label.
1544 identifyScopeMarkers();
1546 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1547 // belongs to so that we add to the correct per-cu line table in the
1548 // non-asm case.
1549 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1550 // FnScope->getScopeNode() and DI->second should represent the same function,
1551 // though they may not be the same MDNode due to inline functions merged in
1552 // LTO where the debug info metadata still differs (either due to distinct
1553 // written differences - two versions of a linkonce_odr function
1554 // written/copied into two separate files, or some sub-optimal metadata that
1555 // isn't structurally identical (see: file path/name info from clang, which
1556 // includes the directory of the cpp file being built, even when the file name
1557 // is absolute (such as an <> lookup header)))
1558 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1559 assert(TheCU && "Unable to find compile unit!");
1560 if (Asm->OutStreamer.hasRawTextSupport())
1561 // Use a single line table if we are generating assembly.
1562 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1563 else
1564 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1566 // Emit a label for the function so that we have a beginning address.
1567 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1568 // Assumes in correct section after the entry point.
1569 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1571 // Calculate history for local variables.
1572 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1573 DbgValues);
1575 // Request labels for the full history.
1576 for (const auto &I : DbgValues) {
1577 const auto &Ranges = I.second;
1578 if (Ranges.empty())
1579 continue;
1581 // The first mention of a function argument gets the FunctionBeginSym
1582 // label, so arguments are visible when breaking at function entry.
1583 DIVariable DV(Ranges.front().first->getDebugVariable());
1584 if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
1585 getDISubprogram(DV.getContext()).describes(MF->getFunction())) {
1586 if (!DV.isVariablePiece())
1587 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1588 else {
1589 // Mark all non-overlapping initial pieces.
1590 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1591 DIVariable Piece = I->first->getDebugVariable();
1592 if (std::all_of(Ranges.begin(), I,
1593 [&](DbgValueHistoryMap::InstrRange Pred){
1594 return !piecesOverlap(Piece, Pred.first->getDebugVariable());
1595 }))
1596 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1597 else
1598 break;
1599 }
1600 }
1601 }
1603 for (const auto &Range : Ranges) {
1604 requestLabelBeforeInsn(Range.first);
1605 if (Range.second)
1606 requestLabelAfterInsn(Range.second);
1607 }
1608 }
1610 PrevInstLoc = DebugLoc();
1611 PrevLabel = FunctionBeginSym;
1613 // Record beginning of function.
1614 PrologEndLoc = findPrologueEndLoc(MF);
1615 if (!PrologEndLoc.isUnknown()) {
1616 DebugLoc FnStartDL =
1617 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1618 recordSourceLine(
1619 FnStartDL.getLine(), FnStartDL.getCol(),
1620 FnStartDL.getScope(MF->getFunction()->getContext()),
1621 // We'd like to list the prologue as "not statements" but GDB behaves
1622 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1623 DWARF2_FLAG_IS_STMT);
1624 }
1625 }
1627 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1628 if (addCurrentFnArgument(Var, LS))
1629 return;
1630 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1631 DIVariable DV = Var->getVariable();
1632 // Variables with positive arg numbers are parameters.
1633 if (unsigned ArgNum = DV.getArgNumber()) {
1634 // Keep all parameters in order at the start of the variable list to ensure
1635 // function types are correct (no out-of-order parameters)
1636 //
1637 // This could be improved by only doing it for optimized builds (unoptimized
1638 // builds have the right order to begin with), searching from the back (this
1639 // would catch the unoptimized case quickly), or doing a binary search
1640 // rather than linear search.
1641 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1642 while (I != Vars.end()) {
1643 unsigned CurNum = (*I)->getVariable().getArgNumber();
1644 // A local (non-parameter) variable has been found, insert immediately
1645 // before it.
1646 if (CurNum == 0)
1647 break;
1648 // A later indexed parameter has been found, insert immediately before it.
1649 if (CurNum > ArgNum)
1650 break;
1651 ++I;
1652 }
1653 Vars.insert(I, Var);
1654 return;
1655 }
1657 Vars.push_back(Var);
1658 }
1660 // Gather and emit post-function debug information.
1661 void DwarfDebug::endFunction(const MachineFunction *MF) {
1662 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1663 // though the beginFunction may not be called at all.
1664 // We should handle both cases.
1665 if (!CurFn)
1666 CurFn = MF;
1667 else
1668 assert(CurFn == MF);
1669 assert(CurFn != nullptr);
1671 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1672 !FunctionDIs.count(MF->getFunction())) {
1673 // If we don't have a lexical scope for this function then there will
1674 // be a hole in the range information. Keep note of this by setting the
1675 // previously used section to nullptr.
1676 PrevCU = nullptr;
1677 CurFn = nullptr;
1678 return;
1679 }
1681 // Define end label for subprogram.
1682 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1683 // Assumes in correct section after the entry point.
1684 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1686 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1687 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1689 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1690 collectVariableInfo(ProcessedVars);
1692 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1693 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1695 // Add the range of this function to the list of ranges for the CU.
1696 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1698 // Under -gmlt, skip building the subprogram if there are no inlined
1699 // subroutines inside it.
1700 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1701 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1702 assert(ScopeVariables.empty());
1703 assert(CurrentFnArguments.empty());
1704 assert(DbgValues.empty());
1705 assert(AbstractVariables.empty());
1706 LabelsBeforeInsn.clear();
1707 LabelsAfterInsn.clear();
1708 PrevLabel = nullptr;
1709 CurFn = nullptr;
1710 return;
1711 }
1713 // Construct abstract scopes.
1714 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1715 DISubprogram SP(AScope->getScopeNode());
1716 assert(SP.isSubprogram());
1717 // Collect info for variables that were optimized out.
1718 DIArray Variables = SP.getVariables();
1719 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1720 DIVariable DV(Variables.getElement(i));
1721 assert(DV && DV.isVariable());
1722 if (!ProcessedVars.insert(DV))
1723 continue;
1724 ensureAbstractVariableIsCreated(DV, DV.getContext());
1725 }
1726 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1727 }
1729 constructSubprogramScopeDIE(TheCU, FnScope);
1731 // Clear debug info
1732 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1733 // DbgVariables except those that are also in AbstractVariables (since they
1734 // can be used cross-function)
1735 ScopeVariables.clear();
1736 CurrentFnArguments.clear();
1737 DbgValues.clear();
1738 LabelsBeforeInsn.clear();
1739 LabelsAfterInsn.clear();
1740 PrevLabel = nullptr;
1741 CurFn = nullptr;
1742 }
1744 // Register a source line with debug info. Returns the unique label that was
1745 // emitted and which provides correspondence to the source line list.
1746 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1747 unsigned Flags) {
1748 StringRef Fn;
1749 StringRef Dir;
1750 unsigned Src = 1;
1751 unsigned Discriminator = 0;
1752 if (DIScope Scope = DIScope(S)) {
1753 assert(Scope.isScope());
1754 Fn = Scope.getFilename();
1755 Dir = Scope.getDirectory();
1756 if (Scope.isLexicalBlockFile())
1757 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1759 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1760 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1761 .getOrCreateSourceID(Fn, Dir);
1762 }
1763 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1764 Discriminator, Fn);
1765 }
1767 //===----------------------------------------------------------------------===//
1768 // Emit Methods
1769 //===----------------------------------------------------------------------===//
1771 // Emit initial Dwarf sections with a label at the start of each one.
1772 void DwarfDebug::emitSectionLabels() {
1773 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1775 // Dwarf sections base addresses.
1776 DwarfInfoSectionSym =
1777 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1778 if (useSplitDwarf()) {
1779 DwarfInfoDWOSectionSym =
1780 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1781 DwarfTypesDWOSectionSym =
1782 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1783 }
1784 DwarfAbbrevSectionSym =
1785 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1786 if (useSplitDwarf())
1787 DwarfAbbrevDWOSectionSym = emitSectionSym(
1788 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1789 if (GenerateARangeSection)
1790 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1792 DwarfLineSectionSym =
1793 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1794 if (GenerateGnuPubSections) {
1795 DwarfGnuPubNamesSectionSym =
1796 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1797 DwarfGnuPubTypesSectionSym =
1798 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1799 } else if (HasDwarfPubSections) {
1800 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1801 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1802 }
1804 DwarfStrSectionSym =
1805 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1806 if (useSplitDwarf()) {
1807 DwarfStrDWOSectionSym =
1808 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1809 DwarfAddrSectionSym =
1810 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1811 DwarfDebugLocSectionSym =
1812 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1813 } else
1814 DwarfDebugLocSectionSym =
1815 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1816 DwarfDebugRangeSectionSym =
1817 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1818 }
1820 // Recursively emits a debug information entry.
1821 void DwarfDebug::emitDIE(DIE &Die) {
1822 // Get the abbreviation for this DIE.
1823 const DIEAbbrev &Abbrev = Die.getAbbrev();
1825 // Emit the code (index) for the abbreviation.
1826 if (Asm->isVerbose())
1827 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1828 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1829 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1830 dwarf::TagString(Abbrev.getTag()));
1831 Asm->EmitULEB128(Abbrev.getNumber());
1833 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1834 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1836 // Emit the DIE attribute values.
1837 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1838 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1839 dwarf::Form Form = AbbrevData[i].getForm();
1840 assert(Form && "Too many attributes for DIE (check abbreviation)");
1842 if (Asm->isVerbose()) {
1843 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1844 if (Attr == dwarf::DW_AT_accessibility)
1845 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1846 cast<DIEInteger>(Values[i])->getValue()));
1847 }
1849 // Emit an attribute using the defined form.
1850 Values[i]->EmitValue(Asm, Form);
1851 }
1853 // Emit the DIE children if any.
1854 if (Abbrev.hasChildren()) {
1855 for (auto &Child : Die.getChildren())
1856 emitDIE(*Child);
1858 Asm->OutStreamer.AddComment("End Of Children Mark");
1859 Asm->EmitInt8(0);
1860 }
1861 }
1863 // Emit the debug info section.
1864 void DwarfDebug::emitDebugInfo() {
1865 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1867 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1868 }
1870 // Emit the abbreviation section.
1871 void DwarfDebug::emitAbbreviations() {
1872 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1874 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1875 }
1877 // Emit the last address of the section and the end of the line matrix.
1878 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1879 // Define last address of section.
1880 Asm->OutStreamer.AddComment("Extended Op");
1881 Asm->EmitInt8(0);
1883 Asm->OutStreamer.AddComment("Op size");
1884 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1885 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1886 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1888 Asm->OutStreamer.AddComment("Section end label");
1890 Asm->OutStreamer.EmitSymbolValue(
1891 Asm->GetTempSymbol("section_end", SectionEnd),
1892 Asm->getDataLayout().getPointerSize());
1894 // Mark end of matrix.
1895 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1896 Asm->EmitInt8(0);
1897 Asm->EmitInt8(1);
1898 Asm->EmitInt8(1);
1899 }
1901 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1902 StringRef TableName, StringRef SymName) {
1903 Accel.FinalizeTable(Asm, TableName);
1904 Asm->OutStreamer.SwitchSection(Section);
1905 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1906 Asm->OutStreamer.EmitLabel(SectionBegin);
1908 // Emit the full data.
1909 Accel.Emit(Asm, SectionBegin, &InfoHolder, DwarfStrSectionSym);
1910 }
1912 // Emit visible names into a hashed accelerator table section.
1913 void DwarfDebug::emitAccelNames() {
1914 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1915 "Names", "names_begin");
1916 }
1918 // Emit objective C classes and categories into a hashed accelerator table
1919 // section.
1920 void DwarfDebug::emitAccelObjC() {
1921 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1922 "ObjC", "objc_begin");
1923 }
1925 // Emit namespace dies into a hashed accelerator table.
1926 void DwarfDebug::emitAccelNamespaces() {
1927 emitAccel(AccelNamespace,
1928 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1929 "namespac", "namespac_begin");
1930 }
1932 // Emit type dies into a hashed accelerator table.
1933 void DwarfDebug::emitAccelTypes() {
1934 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1935 "types", "types_begin");
1936 }
1938 // Public name handling.
1939 // The format for the various pubnames:
1940 //
1941 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1942 // for the DIE that is named.
1943 //
1944 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1945 // into the CU and the index value is computed according to the type of value
1946 // for the DIE that is named.
1947 //
1948 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1949 // it's the offset within the debug_info/debug_types dwo section, however, the
1950 // reference in the pubname header doesn't change.
1952 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1953 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1954 const DIE *Die) {
1955 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1957 // We could have a specification DIE that has our most of our knowledge,
1958 // look for that now.
1959 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1960 if (SpecVal) {
1961 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1962 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1963 Linkage = dwarf::GIEL_EXTERNAL;
1964 } else if (Die->findAttribute(dwarf::DW_AT_external))
1965 Linkage = dwarf::GIEL_EXTERNAL;
1967 switch (Die->getTag()) {
1968 case dwarf::DW_TAG_class_type:
1969 case dwarf::DW_TAG_structure_type:
1970 case dwarf::DW_TAG_union_type:
1971 case dwarf::DW_TAG_enumeration_type:
1972 return dwarf::PubIndexEntryDescriptor(
1973 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1974 ? dwarf::GIEL_STATIC
1975 : dwarf::GIEL_EXTERNAL);
1976 case dwarf::DW_TAG_typedef:
1977 case dwarf::DW_TAG_base_type:
1978 case dwarf::DW_TAG_subrange_type:
1979 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1980 case dwarf::DW_TAG_namespace:
1981 return dwarf::GIEK_TYPE;
1982 case dwarf::DW_TAG_subprogram:
1983 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1984 case dwarf::DW_TAG_constant:
1985 case dwarf::DW_TAG_variable:
1986 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1987 case dwarf::DW_TAG_enumerator:
1988 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1989 dwarf::GIEL_STATIC);
1990 default:
1991 return dwarf::GIEK_NONE;
1992 }
1993 }
1995 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1996 ///
1997 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1998 const MCSection *PSec =
1999 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
2000 : Asm->getObjFileLowering().getDwarfPubNamesSection();
2002 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
2003 }
2005 void DwarfDebug::emitDebugPubSection(
2006 bool GnuStyle, const MCSection *PSec, StringRef Name,
2007 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
2008 for (const auto &NU : CUMap) {
2009 DwarfCompileUnit *TheU = NU.second;
2011 const auto &Globals = (TheU->*Accessor)();
2013 if (Globals.empty())
2014 continue;
2016 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
2017 TheU = Skeleton;
2018 unsigned ID = TheU->getUniqueID();
2020 // Start the dwarf pubnames section.
2021 Asm->OutStreamer.SwitchSection(PSec);
2023 // Emit the header.
2024 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
2025 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
2026 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
2027 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
2029 Asm->OutStreamer.EmitLabel(BeginLabel);
2031 Asm->OutStreamer.AddComment("DWARF Version");
2032 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
2034 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
2035 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
2037 Asm->OutStreamer.AddComment("Compilation Unit Length");
2038 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
2040 // Emit the pubnames for this compilation unit.
2041 for (const auto &GI : Globals) {
2042 const char *Name = GI.getKeyData();
2043 const DIE *Entity = GI.second;
2045 Asm->OutStreamer.AddComment("DIE offset");
2046 Asm->EmitInt32(Entity->getOffset());
2048 if (GnuStyle) {
2049 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
2050 Asm->OutStreamer.AddComment(
2051 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
2052 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
2053 Asm->EmitInt8(Desc.toBits());
2054 }
2056 Asm->OutStreamer.AddComment("External Name");
2057 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
2058 }
2060 Asm->OutStreamer.AddComment("End Mark");
2061 Asm->EmitInt32(0);
2062 Asm->OutStreamer.EmitLabel(EndLabel);
2063 }
2064 }
2066 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
2067 const MCSection *PSec =
2068 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
2069 : Asm->getObjFileLowering().getDwarfPubTypesSection();
2071 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
2072 }
2074 // Emit visible names into a debug str section.
2075 void DwarfDebug::emitDebugStr() {
2076 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
2077 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
2078 }
2080 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
2081 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
2082 const DITypeIdentifierMap &Map,
2083 ArrayRef<DebugLocEntry::Value> Values) {
2084 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
2085 return P.isVariablePiece();
2086 }) && "all values are expected to be pieces");
2087 assert(std::is_sorted(Values.begin(), Values.end()) &&
2088 "pieces are expected to be sorted");
2090 unsigned Offset = 0;
2091 for (auto Piece : Values) {
2092 DIVariable Var = Piece.getVariable();
2093 unsigned PieceOffset = Var.getPieceOffset();
2094 unsigned PieceSize = Var.getPieceSize();
2095 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
2096 if (Offset < PieceOffset) {
2097 // The DWARF spec seriously mandates pieces with no locations for gaps.
2098 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
2099 Offset += PieceOffset-Offset;
2100 }
2102 Offset += PieceSize;
2104 const unsigned SizeOfByte = 8;
2105 assert(!Var.isIndirect() && "indirect address for piece");
2106 #ifndef NDEBUG
2107 unsigned VarSize = Var.getSizeInBits(Map);
2108 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
2109 && "piece is larger than or outside of variable");
2110 assert(PieceSize*SizeOfByte != VarSize
2111 && "piece covers entire variable");
2112 #endif
2113 if (Piece.isLocation() && Piece.getLoc().isReg())
2114 Asm->EmitDwarfRegOpPiece(Streamer,
2115 Piece.getLoc(),
2116 PieceSize*SizeOfByte);
2117 else {
2118 emitDebugLocValue(Streamer, Piece);
2119 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
2120 }
2121 }
2122 }
2125 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
2126 const DebugLocEntry &Entry) {
2127 const DebugLocEntry::Value Value = Entry.getValues()[0];
2128 if (Value.isVariablePiece())
2129 // Emit all pieces that belong to the same variable and range.
2130 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
2132 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
2133 emitDebugLocValue(Streamer, Value);
2134 }
2136 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
2137 const DebugLocEntry::Value &Value) {
2138 DIVariable DV = Value.getVariable();
2139 // Regular entry.
2140 if (Value.isInt()) {
2141 DIBasicType BTy(resolve(DV.getType()));
2142 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
2143 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
2144 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
2145 Streamer.EmitSLEB128(Value.getInt());
2146 } else {
2147 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
2148 Streamer.EmitULEB128(Value.getInt());
2149 }
2150 } else if (Value.isLocation()) {
2151 MachineLocation Loc = Value.getLoc();
2152 if (!DV.hasComplexAddress())
2153 // Regular entry.
2154 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2155 else {
2156 // Complex address entry.
2157 unsigned N = DV.getNumAddrElements();
2158 unsigned i = 0;
2159 if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
2160 if (Loc.getOffset()) {
2161 i = 2;
2162 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2163 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2164 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2165 Streamer.EmitSLEB128(DV.getAddrElement(1));
2166 } else {
2167 // If first address element is OpPlus then emit
2168 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
2169 MachineLocation TLoc(Loc.getReg(), DV.getAddrElement(1));
2170 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
2171 i = 2;
2172 }
2173 } else {
2174 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2175 }
2177 // Emit remaining complex address elements.
2178 for (; i < N; ++i) {
2179 uint64_t Element = DV.getAddrElement(i);
2180 if (Element == DIBuilder::OpPlus) {
2181 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2182 Streamer.EmitULEB128(DV.getAddrElement(++i));
2183 } else if (Element == DIBuilder::OpDeref) {
2184 if (!Loc.isReg())
2185 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2186 } else if (Element == DIBuilder::OpPiece) {
2187 i += 3;
2188 // handled in emitDebugLocEntry.
2189 } else
2190 llvm_unreachable("unknown Opcode found in complex address");
2191 }
2192 }
2193 }
2194 // else ... ignore constant fp. There is not any good way to
2195 // to represent them here in dwarf.
2196 // FIXME: ^
2197 }
2199 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
2200 Asm->OutStreamer.AddComment("Loc expr size");
2201 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
2202 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
2203 Asm->EmitLabelDifference(end, begin, 2);
2204 Asm->OutStreamer.EmitLabel(begin);
2205 // Emit the entry.
2206 APByteStreamer Streamer(*Asm);
2207 emitDebugLocEntry(Streamer, Entry);
2208 // Close the range.
2209 Asm->OutStreamer.EmitLabel(end);
2210 }
2212 // Emit locations into the debug loc section.
2213 void DwarfDebug::emitDebugLoc() {
2214 // Start the dwarf loc section.
2215 Asm->OutStreamer.SwitchSection(
2216 Asm->getObjFileLowering().getDwarfLocSection());
2217 unsigned char Size = Asm->getDataLayout().getPointerSize();
2218 for (const auto &DebugLoc : DotDebugLocEntries) {
2219 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2220 const DwarfCompileUnit *CU = DebugLoc.CU;
2221 assert(!CU->getRanges().empty());
2222 for (const auto &Entry : DebugLoc.List) {
2223 // Set up the range. This range is relative to the entry point of the
2224 // compile unit. This is a hard coded 0 for low_pc when we're emitting
2225 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
2226 if (CU->getRanges().size() == 1) {
2227 // Grab the begin symbol from the first range as our base.
2228 const MCSymbol *Base = CU->getRanges()[0].getStart();
2229 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
2230 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
2231 } else {
2232 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
2233 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
2234 }
2236 emitDebugLocEntryLocation(Entry);
2237 }
2238 Asm->OutStreamer.EmitIntValue(0, Size);
2239 Asm->OutStreamer.EmitIntValue(0, Size);
2240 }
2241 }
2243 void DwarfDebug::emitDebugLocDWO() {
2244 Asm->OutStreamer.SwitchSection(
2245 Asm->getObjFileLowering().getDwarfLocDWOSection());
2246 for (const auto &DebugLoc : DotDebugLocEntries) {
2247 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2248 for (const auto &Entry : DebugLoc.List) {
2249 // Just always use start_length for now - at least that's one address
2250 // rather than two. We could get fancier and try to, say, reuse an
2251 // address we know we've emitted elsewhere (the start of the function?
2252 // The start of the CU or CU subrange that encloses this range?)
2253 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2254 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2255 Asm->EmitULEB128(idx);
2256 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2258 emitDebugLocEntryLocation(Entry);
2259 }
2260 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2261 }
2262 }
2264 struct ArangeSpan {
2265 const MCSymbol *Start, *End;
2266 };
2268 // Emit a debug aranges section, containing a CU lookup for any
2269 // address we can tie back to a CU.
2270 void DwarfDebug::emitDebugARanges() {
2271 // Start the dwarf aranges section.
2272 Asm->OutStreamer.SwitchSection(
2273 Asm->getObjFileLowering().getDwarfARangesSection());
2275 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2277 SpansType Spans;
2279 // Build a list of sections used.
2280 std::vector<const MCSection *> Sections;
2281 for (const auto &it : SectionMap) {
2282 const MCSection *Section = it.first;
2283 Sections.push_back(Section);
2284 }
2286 // Sort the sections into order.
2287 // This is only done to ensure consistent output order across different runs.
2288 std::sort(Sections.begin(), Sections.end(), SectionSort);
2290 // Build a set of address spans, sorted by CU.
2291 for (const MCSection *Section : Sections) {
2292 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2293 if (List.size() < 2)
2294 continue;
2296 // Sort the symbols by offset within the section.
2297 std::sort(List.begin(), List.end(),
2298 [&](const SymbolCU &A, const SymbolCU &B) {
2299 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2300 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2302 // Symbols with no order assigned should be placed at the end.
2303 // (e.g. section end labels)
2304 if (IA == 0)
2305 return false;
2306 if (IB == 0)
2307 return true;
2308 return IA < IB;
2309 });
2311 // If we have no section (e.g. common), just write out
2312 // individual spans for each symbol.
2313 if (!Section) {
2314 for (const SymbolCU &Cur : List) {
2315 ArangeSpan Span;
2316 Span.Start = Cur.Sym;
2317 Span.End = nullptr;
2318 if (Cur.CU)
2319 Spans[Cur.CU].push_back(Span);
2320 }
2321 } else {
2322 // Build spans between each label.
2323 const MCSymbol *StartSym = List[0].Sym;
2324 for (size_t n = 1, e = List.size(); n < e; n++) {
2325 const SymbolCU &Prev = List[n - 1];
2326 const SymbolCU &Cur = List[n];
2328 // Try and build the longest span we can within the same CU.
2329 if (Cur.CU != Prev.CU) {
2330 ArangeSpan Span;
2331 Span.Start = StartSym;
2332 Span.End = Cur.Sym;
2333 Spans[Prev.CU].push_back(Span);
2334 StartSym = Cur.Sym;
2335 }
2336 }
2337 }
2338 }
2340 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2342 // Build a list of CUs used.
2343 std::vector<DwarfCompileUnit *> CUs;
2344 for (const auto &it : Spans) {
2345 DwarfCompileUnit *CU = it.first;
2346 CUs.push_back(CU);
2347 }
2349 // Sort the CU list (again, to ensure consistent output order).
2350 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2351 return A->getUniqueID() < B->getUniqueID();
2352 });
2354 // Emit an arange table for each CU we used.
2355 for (DwarfCompileUnit *CU : CUs) {
2356 std::vector<ArangeSpan> &List = Spans[CU];
2358 // Emit size of content not including length itself.
2359 unsigned ContentSize =
2360 sizeof(int16_t) + // DWARF ARange version number
2361 sizeof(int32_t) + // Offset of CU in the .debug_info section
2362 sizeof(int8_t) + // Pointer Size (in bytes)
2363 sizeof(int8_t); // Segment Size (in bytes)
2365 unsigned TupleSize = PtrSize * 2;
2367 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2368 unsigned Padding =
2369 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2371 ContentSize += Padding;
2372 ContentSize += (List.size() + 1) * TupleSize;
2374 // For each compile unit, write the list of spans it covers.
2375 Asm->OutStreamer.AddComment("Length of ARange Set");
2376 Asm->EmitInt32(ContentSize);
2377 Asm->OutStreamer.AddComment("DWARF Arange version number");
2378 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2379 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2380 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2381 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2382 Asm->EmitInt8(PtrSize);
2383 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2384 Asm->EmitInt8(0);
2386 Asm->OutStreamer.EmitFill(Padding, 0xff);
2388 for (const ArangeSpan &Span : List) {
2389 Asm->EmitLabelReference(Span.Start, PtrSize);
2391 // Calculate the size as being from the span start to it's end.
2392 if (Span.End) {
2393 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2394 } else {
2395 // For symbols without an end marker (e.g. common), we
2396 // write a single arange entry containing just that one symbol.
2397 uint64_t Size = SymSize[Span.Start];
2398 if (Size == 0)
2399 Size = 1;
2401 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2402 }
2403 }
2405 Asm->OutStreamer.AddComment("ARange terminator");
2406 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2407 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2408 }
2409 }
2411 // Emit visible names into a debug ranges section.
2412 void DwarfDebug::emitDebugRanges() {
2413 // Start the dwarf ranges section.
2414 Asm->OutStreamer.SwitchSection(
2415 Asm->getObjFileLowering().getDwarfRangesSection());
2417 // Size for our labels.
2418 unsigned char Size = Asm->getDataLayout().getPointerSize();
2420 // Grab the specific ranges for the compile units in the module.
2421 for (const auto &I : CUMap) {
2422 DwarfCompileUnit *TheCU = I.second;
2424 // Iterate over the misc ranges for the compile units in the module.
2425 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2426 // Emit our symbol so we can find the beginning of the range.
2427 Asm->OutStreamer.EmitLabel(List.getSym());
2429 for (const RangeSpan &Range : List.getRanges()) {
2430 const MCSymbol *Begin = Range.getStart();
2431 const MCSymbol *End = Range.getEnd();
2432 assert(Begin && "Range without a begin symbol?");
2433 assert(End && "Range without an end symbol?");
2434 if (TheCU->getRanges().size() == 1) {
2435 // Grab the begin symbol from the first range as our base.
2436 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2437 Asm->EmitLabelDifference(Begin, Base, Size);
2438 Asm->EmitLabelDifference(End, Base, Size);
2439 } else {
2440 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2441 Asm->OutStreamer.EmitSymbolValue(End, Size);
2442 }
2443 }
2445 // And terminate the list with two 0 values.
2446 Asm->OutStreamer.EmitIntValue(0, Size);
2447 Asm->OutStreamer.EmitIntValue(0, Size);
2448 }
2450 // Now emit a range for the CU itself.
2451 if (TheCU->getRanges().size() > 1) {
2452 Asm->OutStreamer.EmitLabel(
2453 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2454 for (const RangeSpan &Range : TheCU->getRanges()) {
2455 const MCSymbol *Begin = Range.getStart();
2456 const MCSymbol *End = Range.getEnd();
2457 assert(Begin && "Range without a begin symbol?");
2458 assert(End && "Range without an end symbol?");
2459 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2460 Asm->OutStreamer.EmitSymbolValue(End, Size);
2461 }
2462 // And terminate the list with two 0 values.
2463 Asm->OutStreamer.EmitIntValue(0, Size);
2464 Asm->OutStreamer.EmitIntValue(0, Size);
2465 }
2466 }
2467 }
2469 // DWARF5 Experimental Separate Dwarf emitters.
2471 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2472 std::unique_ptr<DwarfUnit> NewU) {
2473 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2474 U.getCUNode().getSplitDebugFilename());
2476 if (!CompilationDir.empty())
2477 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2479 addGnuPubAttributes(*NewU, Die);
2481 SkeletonHolder.addUnit(std::move(NewU));
2482 }
2484 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2485 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2486 // DW_AT_addr_base, DW_AT_ranges_base.
2487 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2489 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2490 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2491 DwarfCompileUnit &NewCU = *OwnedUnit;
2492 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2493 DwarfInfoSectionSym);
2495 NewCU.initStmtList(DwarfLineSectionSym);
2497 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2499 return NewCU;
2500 }
2502 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2503 // compile units that would normally be in debug_info.
2504 void DwarfDebug::emitDebugInfoDWO() {
2505 assert(useSplitDwarf() && "No split dwarf debug info?");
2506 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2507 // emit relocations into the dwo file.
2508 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2509 }
2511 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2512 // abbreviations for the .debug_info.dwo section.
2513 void DwarfDebug::emitDebugAbbrevDWO() {
2514 assert(useSplitDwarf() && "No split dwarf?");
2515 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2516 }
2518 void DwarfDebug::emitDebugLineDWO() {
2519 assert(useSplitDwarf() && "No split dwarf?");
2520 Asm->OutStreamer.SwitchSection(
2521 Asm->getObjFileLowering().getDwarfLineDWOSection());
2522 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2523 }
2525 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2526 // string section and is identical in format to traditional .debug_str
2527 // sections.
2528 void DwarfDebug::emitDebugStrDWO() {
2529 assert(useSplitDwarf() && "No split dwarf?");
2530 const MCSection *OffSec =
2531 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2532 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2533 OffSec);
2534 }
2536 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2537 if (!useSplitDwarf())
2538 return nullptr;
2539 if (SingleCU)
2540 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2541 return &SplitTypeUnitFileTable;
2542 }
2544 static uint64_t makeTypeSignature(StringRef Identifier) {
2545 MD5 Hash;
2546 Hash.update(Identifier);
2547 // ... take the least significant 8 bytes and return those. Our MD5
2548 // implementation always returns its results in little endian, swap bytes
2549 // appropriately.
2550 MD5::MD5Result Result;
2551 Hash.final(Result);
2552 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2553 }
2555 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2556 StringRef Identifier, DIE &RefDie,
2557 DICompositeType CTy) {
2558 // Fast path if we're building some type units and one has already used the
2559 // address pool we know we're going to throw away all this work anyway, so
2560 // don't bother building dependent types.
2561 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2562 return;
2564 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2565 if (TU) {
2566 CU.addDIETypeSignature(RefDie, *TU);
2567 return;
2568 }
2570 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2571 AddrPool.resetUsedFlag();
2573 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2574 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2575 this, &InfoHolder, getDwoLineTable(CU));
2576 DwarfTypeUnit &NewTU = *OwnedUnit;
2577 DIE &UnitDie = NewTU.getUnitDie();
2578 TU = &NewTU;
2579 TypeUnitsUnderConstruction.push_back(
2580 std::make_pair(std::move(OwnedUnit), CTy));
2582 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2583 CU.getLanguage());
2585 uint64_t Signature = makeTypeSignature(Identifier);
2586 NewTU.setTypeSignature(Signature);
2588 if (useSplitDwarf())
2589 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2590 DwarfTypesDWOSectionSym);
2591 else {
2592 CU.applyStmtList(UnitDie);
2593 NewTU.initSection(
2594 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2595 }
2597 NewTU.setType(NewTU.createTypeDIE(CTy));
2599 if (TopLevelType) {
2600 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2601 TypeUnitsUnderConstruction.clear();
2603 // Types referencing entries in the address table cannot be placed in type
2604 // units.
2605 if (AddrPool.hasBeenUsed()) {
2607 // Remove all the types built while building this type.
2608 // This is pessimistic as some of these types might not be dependent on
2609 // the type that used an address.
2610 for (const auto &TU : TypeUnitsToAdd)
2611 DwarfTypeUnits.erase(TU.second);
2613 // Construct this type in the CU directly.
2614 // This is inefficient because all the dependent types will be rebuilt
2615 // from scratch, including building them in type units, discovering that
2616 // they depend on addresses, throwing them out and rebuilding them.
2617 CU.constructTypeDIE(RefDie, CTy);
2618 return;
2619 }
2621 // If the type wasn't dependent on fission addresses, finish adding the type
2622 // and all its dependent types.
2623 for (auto &TU : TypeUnitsToAdd)
2624 InfoHolder.addUnit(std::move(TU.first));
2625 }
2626 CU.addDIETypeSignature(RefDie, NewTU);
2627 }
2629 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2630 const MCSymbol *Begin, const MCSymbol *End) {
2631 assert(Begin && "Begin label should not be null!");
2632 assert(End && "End label should not be null!");
2633 assert(Begin->isDefined() && "Invalid starting label");
2634 assert(End->isDefined() && "Invalid end label");
2636 Unit.addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
2637 if (DwarfVersion < 4)
2638 Unit.addLabelAddress(D, dwarf::DW_AT_high_pc, End);
2639 else
2640 Unit.addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
2641 }
2643 // Accelerator table mutators - add each name along with its companion
2644 // DIE to the proper table while ensuring that the name that we're going
2645 // to reference is in the string table. We do this since the names we
2646 // add may not only be identical to the names in the DIE.
2647 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2648 if (!useDwarfAccelTables())
2649 return;
2650 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2651 &Die);
2652 }
2654 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2655 if (!useDwarfAccelTables())
2656 return;
2657 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2658 &Die);
2659 }
2661 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2662 if (!useDwarfAccelTables())
2663 return;
2664 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2665 &Die);
2666 }
2668 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2669 if (!useDwarfAccelTables())
2670 return;
2671 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2672 &Die);
2673 }