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 using namespace llvm;
53 #define DEBUG_TYPE "dwarfdebug"
55 static cl::opt<bool>
56 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
57 cl::desc("Disable debug info printing"));
59 static cl::opt<bool> UnknownLocations(
60 "use-unknown-locations", cl::Hidden,
61 cl::desc("Make an absence of debug location information explicit."),
62 cl::init(false));
64 static cl::opt<bool>
65 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
66 cl::desc("Generate GNU-style pubnames and pubtypes"),
67 cl::init(false));
69 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
70 cl::Hidden,
71 cl::desc("Generate dwarf aranges"),
72 cl::init(false));
74 namespace {
75 enum DefaultOnOff { Default, Enable, Disable };
76 }
78 static cl::opt<DefaultOnOff>
79 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
80 cl::desc("Output prototype dwarf accelerator tables."),
81 cl::values(clEnumVal(Default, "Default for platform"),
82 clEnumVal(Enable, "Enabled"),
83 clEnumVal(Disable, "Disabled"), clEnumValEnd),
84 cl::init(Default));
86 static cl::opt<DefaultOnOff>
87 SplitDwarf("split-dwarf", cl::Hidden,
88 cl::desc("Output DWARF5 split debug info."),
89 cl::values(clEnumVal(Default, "Default for platform"),
90 clEnumVal(Enable, "Enabled"),
91 clEnumVal(Disable, "Disabled"), clEnumValEnd),
92 cl::init(Default));
94 static cl::opt<DefaultOnOff>
95 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
96 cl::desc("Generate DWARF pubnames and pubtypes sections"),
97 cl::values(clEnumVal(Default, "Default for platform"),
98 clEnumVal(Enable, "Enabled"),
99 clEnumVal(Disable, "Disabled"), clEnumValEnd),
100 cl::init(Default));
102 static const char *const DWARFGroupName = "DWARF Emission";
103 static const char *const DbgTimerName = "DWARF Debug Writer";
105 //===----------------------------------------------------------------------===//
107 /// resolve - Look in the DwarfDebug map for the MDNode that
108 /// corresponds to the reference.
109 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
110 return DD->resolve(Ref);
111 }
113 bool DbgVariable::isBlockByrefVariable() const {
114 assert(Var.isVariable() && "Invalid complex DbgVariable!");
115 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
116 }
118 DIType DbgVariable::getType() const {
119 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
120 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
121 // addresses instead.
122 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
123 /* Byref variables, in Blocks, are declared by the programmer as
124 "SomeType VarName;", but the compiler creates a
125 __Block_byref_x_VarName struct, and gives the variable VarName
126 either the struct, or a pointer to the struct, as its type. This
127 is necessary for various behind-the-scenes things the compiler
128 needs to do with by-reference variables in blocks.
130 However, as far as the original *programmer* is concerned, the
131 variable should still have type 'SomeType', as originally declared.
133 The following function dives into the __Block_byref_x_VarName
134 struct to find the original type of the variable. This will be
135 passed back to the code generating the type for the Debug
136 Information Entry for the variable 'VarName'. 'VarName' will then
137 have the original type 'SomeType' in its debug information.
139 The original type 'SomeType' will be the type of the field named
140 'VarName' inside the __Block_byref_x_VarName struct.
142 NOTE: In order for this to not completely fail on the debugger
143 side, the Debug Information Entry for the variable VarName needs to
144 have a DW_AT_location that tells the debugger how to unwind through
145 the pointers and __Block_byref_x_VarName struct to find the actual
146 value of the variable. The function addBlockByrefType does this. */
147 DIType subType = Ty;
148 uint16_t tag = Ty.getTag();
150 if (tag == dwarf::DW_TAG_pointer_type)
151 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
153 DIArray Elements = DICompositeType(subType).getElements();
154 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
155 DIDerivedType DT(Elements.getElement(i));
156 if (getName() == DT.getName())
157 return (resolve(DT.getTypeDerivedFrom()));
158 }
159 }
160 return Ty;
161 }
163 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
164 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
165 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
166 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
168 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
169 : Asm(A), MMI(Asm->MMI), FirstCU(nullptr), PrevLabel(nullptr),
170 GlobalRangeCount(0), InfoHolder(A, "info_string", DIEValueAllocator),
171 UsedNonDefaultText(false),
172 SkeletonHolder(A, "skel_string", DIEValueAllocator),
173 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
174 dwarf::DW_FORM_data4)),
175 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
176 dwarf::DW_FORM_data4)),
177 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelTypes(TypeAtoms) {
181 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
182 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
183 DwarfLineSectionSym = nullptr;
184 DwarfAddrSectionSym = nullptr;
185 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
186 FunctionBeginSym = FunctionEndSym = nullptr;
187 CurFn = nullptr;
188 CurMI = nullptr;
190 // Turn on accelerator tables for Darwin by default, pubnames by
191 // default for non-Darwin, and handle split dwarf.
192 bool IsDarwin = Triple(A->getTargetTriple()).isOSDarwin();
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);
321 const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
322 MachineLocation Location(RI->getFrameRegister(*Asm->MF));
323 SPCU.addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
325 // Add name to the name table, we do this here because we're guaranteed
326 // to have concrete versions of our DW_TAG_subprogram nodes.
327 addSubprogramNames(SP, *SPDie);
329 return *SPDie;
330 }
332 /// Check whether we should create a DIE for the given Scope, return true
333 /// if we don't create a DIE (the corresponding DIE is null).
334 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
335 if (Scope->isAbstractScope())
336 return false;
338 // We don't create a DIE if there is no Range.
339 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
340 if (Ranges.empty())
341 return true;
343 if (Ranges.size() > 1)
344 return false;
346 // We don't create a DIE if we have a single Range and the end label
347 // is null.
348 SmallVectorImpl<InsnRange>::const_iterator RI = Ranges.begin();
349 MCSymbol *End = getLabelAfterInsn(RI->second);
350 return !End;
351 }
353 static void addSectionLabel(AsmPrinter &Asm, DwarfUnit &U, DIE &D,
354 dwarf::Attribute A, const MCSymbol *L,
355 const MCSymbol *Sec) {
356 if (Asm.MAI->doesDwarfUseRelocationsAcrossSections())
357 U.addSectionLabel(D, A, L);
358 else
359 U.addSectionDelta(D, A, L, Sec);
360 }
362 void DwarfDebug::addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
363 const SmallVectorImpl<InsnRange> &Range) {
364 // Emit offset in .debug_range as a relocatable label. emitDIE will handle
365 // emitting it appropriately.
366 MCSymbol *RangeSym = Asm->GetTempSymbol("debug_ranges", GlobalRangeCount++);
368 // Under fission, ranges are specified by constant offsets relative to the
369 // CU's DW_AT_GNU_ranges_base.
370 if (useSplitDwarf())
371 TheCU.addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
372 DwarfDebugRangeSectionSym);
373 else
374 addSectionLabel(*Asm, TheCU, ScopeDIE, dwarf::DW_AT_ranges, RangeSym,
375 DwarfDebugRangeSectionSym);
377 RangeSpanList List(RangeSym);
378 for (const InsnRange &R : Range) {
379 RangeSpan Span(getLabelBeforeInsn(R.first), getLabelAfterInsn(R.second));
380 List.addRange(std::move(Span));
381 }
383 // Add the range list to the set of ranges to be emitted.
384 TheCU.addRangeList(std::move(List));
385 }
387 void DwarfDebug::attachRangesOrLowHighPC(DwarfCompileUnit &TheCU, DIE &Die,
388 const SmallVectorImpl<InsnRange> &Ranges) {
389 assert(!Ranges.empty());
390 if (Ranges.size() == 1)
391 attachLowHighPC(TheCU, Die, getLabelBeforeInsn(Ranges.front().first),
392 getLabelAfterInsn(Ranges.front().second));
393 else
394 addScopeRangeList(TheCU, Die, Ranges);
395 }
397 // Construct new DW_TAG_lexical_block for this scope and attach
398 // DW_AT_low_pc/DW_AT_high_pc labels.
399 std::unique_ptr<DIE>
400 DwarfDebug::constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
401 LexicalScope *Scope) {
402 if (isLexicalScopeDIENull(Scope))
403 return nullptr;
405 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
406 if (Scope->isAbstractScope())
407 return ScopeDIE;
409 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
411 return ScopeDIE;
412 }
414 // This scope represents inlined body of a function. Construct DIE to
415 // represent this concrete inlined copy of the function.
416 std::unique_ptr<DIE>
417 DwarfDebug::constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
418 LexicalScope *Scope) {
419 assert(Scope->getScopeNode());
420 DIScope DS(Scope->getScopeNode());
421 DISubprogram InlinedSP = getDISubprogram(DS);
422 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
423 // was inlined from another compile unit.
424 DIE *OriginDIE = AbstractSPDies[InlinedSP];
425 assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
427 auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
428 TheCU.addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
430 attachRangesOrLowHighPC(TheCU, *ScopeDIE, Scope->getRanges());
432 InlinedSubprogramDIEs.insert(OriginDIE);
434 // Add the call site information to the DIE.
435 DILocation DL(Scope->getInlinedAt());
436 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
437 TheCU.getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
438 TheCU.addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
440 // Add name to the name table, we do this here because we're guaranteed
441 // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
442 addSubprogramNames(InlinedSP, *ScopeDIE);
444 return ScopeDIE;
445 }
447 static std::unique_ptr<DIE> constructVariableDIE(DwarfCompileUnit &TheCU,
448 DbgVariable &DV,
449 const LexicalScope &Scope,
450 DIE *&ObjectPointer) {
451 auto Var = TheCU.constructVariableDIE(DV, Scope.isAbstractScope());
452 if (DV.isObjectPointer())
453 ObjectPointer = Var.get();
454 return Var;
455 }
457 DIE *DwarfDebug::createScopeChildrenDIE(
458 DwarfCompileUnit &TheCU, LexicalScope *Scope,
459 SmallVectorImpl<std::unique_ptr<DIE>> &Children) {
460 DIE *ObjectPointer = nullptr;
462 // Collect arguments for current function.
463 if (LScopes.isCurrentFunctionScope(Scope)) {
464 for (DbgVariable *ArgDV : CurrentFnArguments)
465 if (ArgDV)
466 Children.push_back(
467 constructVariableDIE(TheCU, *ArgDV, *Scope, ObjectPointer));
469 // If this is a variadic function, add an unspecified parameter.
470 DISubprogram SP(Scope->getScopeNode());
471 DITypeArray FnArgs = SP.getType().getTypeArray();
472 // If we have a single element of null, it is a function that returns void.
473 // If we have more than one elements and the last one is null, it is a
474 // variadic function.
475 if (FnArgs.getNumElements() > 1 &&
476 !FnArgs.getElement(FnArgs.getNumElements() - 1))
477 Children.push_back(
478 make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
479 }
481 // Collect lexical scope children first.
482 for (DbgVariable *DV : ScopeVariables.lookup(Scope))
483 Children.push_back(constructVariableDIE(TheCU, *DV, *Scope, ObjectPointer));
485 for (LexicalScope *LS : Scope->getChildren())
486 if (std::unique_ptr<DIE> Nested = constructScopeDIE(TheCU, LS))
487 Children.push_back(std::move(Nested));
488 return ObjectPointer;
489 }
491 void DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU,
492 LexicalScope *Scope, DIE &ScopeDIE) {
493 // We create children when the scope DIE is not null.
494 SmallVector<std::unique_ptr<DIE>, 8> Children;
495 if (DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children))
496 TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
498 // Add children
499 for (auto &I : Children)
500 ScopeDIE.addChild(std::move(I));
501 }
503 void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
504 LexicalScope *Scope) {
505 assert(Scope && Scope->getScopeNode());
506 assert(Scope->isAbstractScope());
507 assert(!Scope->getInlinedAt());
509 DISubprogram SP(Scope->getScopeNode());
511 ProcessedSPNodes.insert(SP);
513 DIE *&AbsDef = AbstractSPDies[SP];
514 if (AbsDef)
515 return;
517 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
518 // was inlined from another compile unit.
519 DwarfCompileUnit &SPCU = *SPMap[SP];
520 DIE *ContextDIE;
522 // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
523 // the important distinction that the DIDescriptor is not associated with the
524 // DIE (since the DIDescriptor will be associated with the concrete DIE, if
525 // any). It could be refactored to some common utility function.
526 if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
527 ContextDIE = &SPCU.getUnitDie();
528 SPCU.getOrCreateSubprogramDIE(SPDecl);
529 } else
530 ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
532 // Passing null as the associated DIDescriptor because the abstract definition
533 // shouldn't be found by lookup.
534 AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
535 DIDescriptor());
536 SPCU.applySubprogramAttributesToDefinition(SP, *AbsDef);
538 SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
539 createAndAddScopeChildren(SPCU, Scope, *AbsDef);
540 }
542 DIE &DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
543 LexicalScope *Scope) {
544 assert(Scope && Scope->getScopeNode());
545 assert(!Scope->getInlinedAt());
546 assert(!Scope->isAbstractScope());
547 DISubprogram Sub(Scope->getScopeNode());
549 assert(Sub.isSubprogram());
551 ProcessedSPNodes.insert(Sub);
553 DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub);
555 createAndAddScopeChildren(TheCU, Scope, ScopeDIE);
557 return ScopeDIE;
558 }
560 // Construct a DIE for this scope.
561 std::unique_ptr<DIE> DwarfDebug::constructScopeDIE(DwarfCompileUnit &TheCU,
562 LexicalScope *Scope) {
563 if (!Scope || !Scope->getScopeNode())
564 return nullptr;
566 DIScope DS(Scope->getScopeNode());
568 assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
569 "Only handle inlined subprograms here, use "
570 "constructSubprogramScopeDIE for non-inlined "
571 "subprograms");
573 SmallVector<std::unique_ptr<DIE>, 8> Children;
575 // We try to create the scope DIE first, then the children DIEs. This will
576 // avoid creating un-used children then removing them later when we find out
577 // the scope DIE is null.
578 std::unique_ptr<DIE> ScopeDIE;
579 if (Scope->getParent() && DS.isSubprogram()) {
580 ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
581 if (!ScopeDIE)
582 return nullptr;
583 // We create children when the scope DIE is not null.
584 createScopeChildrenDIE(TheCU, Scope, Children);
585 } else {
586 // Early exit when we know the scope DIE is going to be null.
587 if (isLexicalScopeDIENull(Scope))
588 return nullptr;
590 // We create children here when we know the scope DIE is not going to be
591 // null and the children will be added to the scope DIE.
592 createScopeChildrenDIE(TheCU, Scope, Children);
594 // There is no need to emit empty lexical block DIE.
595 std::pair<ImportedEntityMap::const_iterator,
596 ImportedEntityMap::const_iterator> Range =
597 std::equal_range(ScopesWithImportedEntities.begin(),
598 ScopesWithImportedEntities.end(),
599 std::pair<const MDNode *, const MDNode *>(DS, nullptr),
600 less_first());
601 if (Children.empty() && Range.first == Range.second)
602 return nullptr;
603 ScopeDIE = constructLexicalScopeDIE(TheCU, Scope);
604 assert(ScopeDIE && "Scope DIE should not be null.");
605 for (ImportedEntityMap::const_iterator i = Range.first; i != Range.second;
606 ++i)
607 constructImportedEntityDIE(TheCU, i->second, *ScopeDIE);
608 }
610 // Add children
611 for (auto &I : Children)
612 ScopeDIE->addChild(std::move(I));
614 return ScopeDIE;
615 }
617 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
618 if (!GenerateGnuPubSections)
619 return;
621 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
622 }
624 // Create new DwarfCompileUnit for the given metadata node with tag
625 // DW_TAG_compile_unit.
626 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
627 StringRef FN = DIUnit.getFilename();
628 CompilationDir = DIUnit.getDirectory();
630 auto OwnedUnit = make_unique<DwarfCompileUnit>(
631 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
632 DwarfCompileUnit &NewCU = *OwnedUnit;
633 DIE &Die = NewCU.getUnitDie();
634 InfoHolder.addUnit(std::move(OwnedUnit));
636 // LTO with assembly output shares a single line table amongst multiple CUs.
637 // To avoid the compilation directory being ambiguous, let the line table
638 // explicitly describe the directory of all files, never relying on the
639 // compilation directory.
640 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
641 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
642 NewCU.getUniqueID(), CompilationDir);
644 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
645 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
646 DIUnit.getLanguage());
647 NewCU.addString(Die, dwarf::DW_AT_name, FN);
649 if (!useSplitDwarf()) {
650 NewCU.initStmtList(DwarfLineSectionSym);
652 // If we're using split dwarf the compilation dir is going to be in the
653 // skeleton CU and so we don't need to duplicate it here.
654 if (!CompilationDir.empty())
655 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
657 addGnuPubAttributes(NewCU, Die);
658 }
660 if (DIUnit.isOptimized())
661 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
663 StringRef Flags = DIUnit.getFlags();
664 if (!Flags.empty())
665 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
667 if (unsigned RVer = DIUnit.getRunTimeVersion())
668 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
669 dwarf::DW_FORM_data1, RVer);
671 if (!FirstCU)
672 FirstCU = &NewCU;
674 if (useSplitDwarf()) {
675 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
676 DwarfInfoDWOSectionSym);
677 NewCU.setSkeleton(constructSkeletonCU(NewCU));
678 } else
679 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
680 DwarfInfoSectionSym);
682 CUMap.insert(std::make_pair(DIUnit, &NewCU));
683 CUDieMap.insert(std::make_pair(&Die, &NewCU));
684 return NewCU;
685 }
687 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
688 const MDNode *N) {
689 DIImportedEntity Module(N);
690 assert(Module.Verify());
691 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
692 constructImportedEntityDIE(TheCU, Module, *D);
693 }
695 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
696 const MDNode *N, DIE &Context) {
697 DIImportedEntity Module(N);
698 assert(Module.Verify());
699 return constructImportedEntityDIE(TheCU, Module, Context);
700 }
702 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
703 const DIImportedEntity &Module,
704 DIE &Context) {
705 assert(Module.Verify() &&
706 "Use one of the MDNode * overloads to handle invalid metadata");
707 DIE &IMDie = TheCU.createAndAddDIE(Module.getTag(), Context, Module);
708 DIE *EntityDie;
709 DIDescriptor Entity = resolve(Module.getEntity());
710 if (Entity.isNameSpace())
711 EntityDie = TheCU.getOrCreateNameSpace(DINameSpace(Entity));
712 else if (Entity.isSubprogram())
713 EntityDie = TheCU.getOrCreateSubprogramDIE(DISubprogram(Entity));
714 else if (Entity.isType())
715 EntityDie = TheCU.getOrCreateTypeDIE(DIType(Entity));
716 else
717 EntityDie = TheCU.getDIE(Entity);
718 TheCU.addSourceLine(IMDie, Module.getLineNumber(),
719 Module.getContext().getFilename(),
720 Module.getContext().getDirectory());
721 TheCU.addDIEEntry(IMDie, dwarf::DW_AT_import, *EntityDie);
722 StringRef Name = Module.getName();
723 if (!Name.empty())
724 TheCU.addString(IMDie, dwarf::DW_AT_name, Name);
725 }
727 // Emit all Dwarf sections that should come prior to the content. Create
728 // global DIEs and emit initial debug info sections. This is invoked by
729 // the target AsmPrinter.
730 void DwarfDebug::beginModule() {
731 if (DisableDebugInfoPrinting)
732 return;
734 const Module *M = MMI->getModule();
736 FunctionDIs = makeSubprogramMap(*M);
738 // If module has named metadata anchors then use them, otherwise scan the
739 // module using debug info finder to collect debug info.
740 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
741 if (!CU_Nodes)
742 return;
743 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
745 // Emit initial sections so we can reference labels later.
746 emitSectionLabels();
748 SingleCU = CU_Nodes->getNumOperands() == 1;
750 for (MDNode *N : CU_Nodes->operands()) {
751 DICompileUnit CUNode(N);
752 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
753 DIArray ImportedEntities = CUNode.getImportedEntities();
754 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
755 ScopesWithImportedEntities.push_back(std::make_pair(
756 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
757 ImportedEntities.getElement(i)));
758 std::sort(ScopesWithImportedEntities.begin(),
759 ScopesWithImportedEntities.end(), less_first());
760 DIArray GVs = CUNode.getGlobalVariables();
761 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
762 CU.createGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
763 DIArray SPs = CUNode.getSubprograms();
764 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
765 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
766 DIArray EnumTypes = CUNode.getEnumTypes();
767 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
768 DIType Ty(EnumTypes.getElement(i));
769 // The enum types array by design contains pointers to
770 // MDNodes rather than DIRefs. Unique them here.
771 DIType UniqueTy(resolve(Ty.getRef()));
772 CU.getOrCreateTypeDIE(UniqueTy);
773 }
774 DIArray RetainedTypes = CUNode.getRetainedTypes();
775 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
776 DIType Ty(RetainedTypes.getElement(i));
777 // The retained types array by design contains pointers to
778 // MDNodes rather than DIRefs. Unique them here.
779 DIType UniqueTy(resolve(Ty.getRef()));
780 CU.getOrCreateTypeDIE(UniqueTy);
781 }
782 // Emit imported_modules last so that the relevant context is already
783 // available.
784 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
785 constructImportedEntityDIE(CU, ImportedEntities.getElement(i));
786 }
788 // Tell MMI that we have debug info.
789 MMI->setDebugInfoAvailability(true);
791 // Prime section data.
792 SectionMap[Asm->getObjFileLowering().getTextSection()];
793 }
795 void DwarfDebug::finishVariableDefinitions() {
796 for (const auto &Var : ConcreteVariables) {
797 DIE *VariableDie = Var->getDIE();
798 // FIXME: There shouldn't be any variables without DIEs.
799 if (!VariableDie)
800 continue;
801 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
802 // in the ConcreteVariables list, rather than looking it up again here.
803 // DIE::getUnit isn't simple - it walks parent pointers, etc.
804 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
805 assert(Unit);
806 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
807 if (AbsVar && AbsVar->getDIE()) {
808 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
809 *AbsVar->getDIE());
810 } else
811 Unit->applyVariableAttributes(*Var, *VariableDie);
812 }
813 }
815 void DwarfDebug::finishSubprogramDefinitions() {
816 const Module *M = MMI->getModule();
818 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
819 for (MDNode *N : CU_Nodes->operands()) {
820 DICompileUnit TheCU(N);
821 // Construct subprogram DIE and add variables DIEs.
822 DwarfCompileUnit *SPCU =
823 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
824 DIArray Subprograms = TheCU.getSubprograms();
825 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
826 DISubprogram SP(Subprograms.getElement(i));
827 // Perhaps the subprogram is in another CU (such as due to comdat
828 // folding, etc), in which case ignore it here.
829 if (SPMap[SP] != SPCU)
830 continue;
831 DIE *D = SPCU->getDIE(SP);
832 if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
833 if (D)
834 // If this subprogram has an abstract definition, reference that
835 SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
836 } else {
837 if (!D)
838 // Lazily construct the subprogram if we didn't see either concrete or
839 // inlined versions during codegen.
840 D = SPCU->getOrCreateSubprogramDIE(SP);
841 // And attach the attributes
842 SPCU->applySubprogramAttributesToDefinition(SP, *D);
843 }
844 }
845 }
846 }
849 // Collect info for variables that were optimized out.
850 void DwarfDebug::collectDeadVariables() {
851 const Module *M = MMI->getModule();
853 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
854 for (MDNode *N : CU_Nodes->operands()) {
855 DICompileUnit TheCU(N);
856 // Construct subprogram DIE and add variables DIEs.
857 DwarfCompileUnit *SPCU =
858 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
859 assert(SPCU && "Unable to find Compile Unit!");
860 DIArray Subprograms = TheCU.getSubprograms();
861 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
862 DISubprogram SP(Subprograms.getElement(i));
863 if (ProcessedSPNodes.count(SP) != 0)
864 continue;
865 assert(SP.isSubprogram() &&
866 "CU's subprogram list contains a non-subprogram");
867 assert(SP.isDefinition() &&
868 "CU's subprogram list contains a subprogram declaration");
869 DIArray Variables = SP.getVariables();
870 if (Variables.getNumElements() == 0)
871 continue;
873 DIE *SPDIE = AbstractSPDies.lookup(SP);
874 if (!SPDIE)
875 SPDIE = SPCU->getDIE(SP);
876 assert(SPDIE);
877 for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
878 DIVariable DV(Variables.getElement(vi));
879 assert(DV.isVariable());
880 DbgVariable NewVar(DV, this);
881 auto VariableDie = SPCU->constructVariableDIE(NewVar);
882 SPCU->applyVariableAttributes(NewVar, *VariableDie);
883 SPDIE->addChild(std::move(VariableDie));
884 }
885 }
886 }
887 }
888 }
890 void DwarfDebug::finalizeModuleInfo() {
891 finishSubprogramDefinitions();
893 finishVariableDefinitions();
895 // Collect info for variables that were optimized out.
896 collectDeadVariables();
898 // Handle anything that needs to be done on a per-unit basis after
899 // all other generation.
900 for (const auto &TheU : getUnits()) {
901 // Emit DW_AT_containing_type attribute to connect types with their
902 // vtable holding type.
903 TheU->constructContainingTypeDIEs();
905 // Add CU specific attributes if we need to add any.
906 if (TheU->getUnitDie().getTag() == dwarf::DW_TAG_compile_unit) {
907 // If we're splitting the dwarf out now that we've got the entire
908 // CU then add the dwo id to it.
909 DwarfCompileUnit *SkCU =
910 static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
911 if (useSplitDwarf()) {
912 // Emit a unique identifier for this CU.
913 uint64_t ID = DIEHash(Asm).computeCUSignature(TheU->getUnitDie());
914 TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
915 dwarf::DW_FORM_data8, ID);
916 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
917 dwarf::DW_FORM_data8, ID);
919 // We don't keep track of which addresses are used in which CU so this
920 // is a bit pessimistic under LTO.
921 if (!AddrPool.isEmpty())
922 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
923 dwarf::DW_AT_GNU_addr_base, DwarfAddrSectionSym,
924 DwarfAddrSectionSym);
925 if (!TheU->getRangeLists().empty())
926 addSectionLabel(*Asm, *SkCU, SkCU->getUnitDie(),
927 dwarf::DW_AT_GNU_ranges_base,
928 DwarfDebugRangeSectionSym, DwarfDebugRangeSectionSym);
929 }
931 // If we have code split among multiple sections or non-contiguous
932 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
933 // remain in the .o file, otherwise add a DW_AT_low_pc.
934 // FIXME: We should use ranges allow reordering of code ala
935 // .subsections_via_symbols in mach-o. This would mean turning on
936 // ranges for all subprogram DIEs for mach-o.
937 DwarfCompileUnit &U =
938 SkCU ? *SkCU : static_cast<DwarfCompileUnit &>(*TheU);
939 unsigned NumRanges = TheU->getRanges().size();
940 if (NumRanges) {
941 if (NumRanges > 1) {
942 addSectionLabel(*Asm, U, U.getUnitDie(), dwarf::DW_AT_ranges,
943 Asm->GetTempSymbol("cu_ranges", U.getUniqueID()),
944 DwarfDebugRangeSectionSym);
946 // A DW_AT_low_pc attribute may also be specified in combination with
947 // DW_AT_ranges to specify the default base address for use in
948 // location lists (see Section 2.6.2) and range lists (see Section
949 // 2.17.3).
950 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr,
951 0);
952 } else {
953 RangeSpan &Range = TheU->getRanges().back();
954 U.addLocalLabelAddress(U.getUnitDie(), dwarf::DW_AT_low_pc,
955 Range.getStart());
956 U.addLabelDelta(U.getUnitDie(), dwarf::DW_AT_high_pc, Range.getEnd(),
957 Range.getStart());
958 }
959 }
960 }
961 }
963 // Compute DIE offsets and sizes.
964 InfoHolder.computeSizeAndOffsets();
965 if (useSplitDwarf())
966 SkeletonHolder.computeSizeAndOffsets();
967 }
969 void DwarfDebug::endSections() {
970 // Filter labels by section.
971 for (const SymbolCU &SCU : ArangeLabels) {
972 if (SCU.Sym->isInSection()) {
973 // Make a note of this symbol and it's section.
974 const MCSection *Section = &SCU.Sym->getSection();
975 if (!Section->getKind().isMetadata())
976 SectionMap[Section].push_back(SCU);
977 } else {
978 // Some symbols (e.g. common/bss on mach-o) can have no section but still
979 // appear in the output. This sucks as we rely on sections to build
980 // arange spans. We can do it without, but it's icky.
981 SectionMap[nullptr].push_back(SCU);
982 }
983 }
985 // Build a list of sections used.
986 std::vector<const MCSection *> Sections;
987 for (const auto &it : SectionMap) {
988 const MCSection *Section = it.first;
989 Sections.push_back(Section);
990 }
992 // Sort the sections into order.
993 // This is only done to ensure consistent output order across different runs.
994 std::sort(Sections.begin(), Sections.end(), SectionSort);
996 // Add terminating symbols for each section.
997 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
998 const MCSection *Section = Sections[ID];
999 MCSymbol *Sym = nullptr;
1001 if (Section) {
1002 // We can't call MCSection::getLabelEndName, as it's only safe to do so
1003 // if we know the section name up-front. For user-created sections, the
1004 // resulting label may not be valid to use as a label. (section names can
1005 // use a greater set of characters on some systems)
1006 Sym = Asm->GetTempSymbol("debug_end", ID);
1007 Asm->OutStreamer.SwitchSection(Section);
1008 Asm->OutStreamer.EmitLabel(Sym);
1009 }
1011 // Insert a final terminator.
1012 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
1013 }
1014 }
1016 // Emit all Dwarf sections that should come after the content.
1017 void DwarfDebug::endModule() {
1018 assert(CurFn == nullptr);
1019 assert(CurMI == nullptr);
1021 if (!FirstCU)
1022 return;
1024 // End any existing sections.
1025 // TODO: Does this need to happen?
1026 endSections();
1028 // Finalize the debug info for the module.
1029 finalizeModuleInfo();
1031 emitDebugStr();
1033 // Emit all the DIEs into a debug info section.
1034 emitDebugInfo();
1036 // Corresponding abbreviations into a abbrev section.
1037 emitAbbreviations();
1039 // Emit info into a debug aranges section.
1040 if (GenerateARangeSection)
1041 emitDebugARanges();
1043 // Emit info into a debug ranges section.
1044 emitDebugRanges();
1046 if (useSplitDwarf()) {
1047 emitDebugStrDWO();
1048 emitDebugInfoDWO();
1049 emitDebugAbbrevDWO();
1050 emitDebugLineDWO();
1051 emitDebugLocDWO();
1052 // Emit DWO addresses.
1053 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
1054 } else
1055 // Emit info into a debug loc section.
1056 emitDebugLoc();
1058 // Emit info into the dwarf accelerator table sections.
1059 if (useDwarfAccelTables()) {
1060 emitAccelNames();
1061 emitAccelObjC();
1062 emitAccelNamespaces();
1063 emitAccelTypes();
1064 }
1066 // Emit the pubnames and pubtypes sections if requested.
1067 if (HasDwarfPubSections) {
1068 emitDebugPubNames(GenerateGnuPubSections);
1069 emitDebugPubTypes(GenerateGnuPubSections);
1070 }
1072 // clean up.
1073 SPMap.clear();
1074 AbstractVariables.clear();
1076 // Reset these for the next Module if we have one.
1077 FirstCU = nullptr;
1078 }
1080 // Find abstract variable, if any, associated with Var.
1081 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
1082 DIVariable &Cleansed) {
1083 LLVMContext &Ctx = DV->getContext();
1084 // More then one inlined variable corresponds to one abstract variable.
1085 // FIXME: This duplication of variables when inlining should probably be
1086 // removed. It's done to allow each DIVariable to describe its location
1087 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
1088 // make it accurate then remove this duplication/cleansing stuff.
1089 Cleansed = cleanseInlinedVariable(DV, Ctx);
1090 auto I = AbstractVariables.find(Cleansed);
1091 if (I != AbstractVariables.end())
1092 return I->second.get();
1093 return nullptr;
1094 }
1096 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
1097 DIVariable Cleansed;
1098 return getExistingAbstractVariable(DV, Cleansed);
1099 }
1101 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
1102 LexicalScope *Scope) {
1103 auto AbsDbgVariable = make_unique<DbgVariable>(Var, this);
1104 addScopeVariable(Scope, AbsDbgVariable.get());
1105 AbstractVariables[Var] = std::move(AbsDbgVariable);
1106 }
1108 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
1109 const MDNode *ScopeNode) {
1110 DIVariable Cleansed = DV;
1111 if (getExistingAbstractVariable(DV, Cleansed))
1112 return;
1114 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
1115 }
1117 void
1118 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
1119 const MDNode *ScopeNode) {
1120 DIVariable Cleansed = DV;
1121 if (getExistingAbstractVariable(DV, Cleansed))
1122 return;
1124 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
1125 createAbstractVariable(Cleansed, Scope);
1126 }
1128 // If Var is a current function argument then add it to CurrentFnArguments list.
1129 bool DwarfDebug::addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope) {
1130 if (!LScopes.isCurrentFunctionScope(Scope))
1131 return false;
1132 DIVariable DV = Var->getVariable();
1133 if (DV.getTag() != dwarf::DW_TAG_arg_variable)
1134 return false;
1135 unsigned ArgNo = DV.getArgNumber();
1136 if (ArgNo == 0)
1137 return false;
1139 size_t Size = CurrentFnArguments.size();
1140 if (Size == 0)
1141 CurrentFnArguments.resize(CurFn->getFunction()->arg_size());
1142 // llvm::Function argument size is not good indicator of how many
1143 // arguments does the function have at source level.
1144 if (ArgNo > Size)
1145 CurrentFnArguments.resize(ArgNo * 2);
1146 CurrentFnArguments[ArgNo - 1] = Var;
1147 return true;
1148 }
1150 // Collect variable information from side table maintained by MMI.
1151 void DwarfDebug::collectVariableInfoFromMMITable(
1152 SmallPtrSet<const MDNode *, 16> &Processed) {
1153 for (const auto &VI : MMI->getVariableDbgInfo()) {
1154 if (!VI.Var)
1155 continue;
1156 Processed.insert(VI.Var);
1157 DIVariable DV(VI.Var);
1158 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
1160 // If variable scope is not found then skip this variable.
1161 if (!Scope)
1162 continue;
1164 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1165 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
1166 DbgVariable *RegVar = ConcreteVariables.back().get();
1167 RegVar->setFrameIndex(VI.Slot);
1168 addScopeVariable(Scope, RegVar);
1169 }
1170 }
1172 // Get .debug_loc entry for the instruction range starting at MI.
1173 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
1174 const MDNode *Var = MI->getDebugVariable();
1176 assert(MI->getNumOperands() == 3);
1177 if (MI->getOperand(0).isReg()) {
1178 MachineLocation MLoc;
1179 // If the second operand is an immediate, this is a
1180 // register-indirect address.
1181 if (!MI->getOperand(1).isImm())
1182 MLoc.set(MI->getOperand(0).getReg());
1183 else
1184 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
1185 return DebugLocEntry::Value(Var, MLoc);
1186 }
1187 if (MI->getOperand(0).isImm())
1188 return DebugLocEntry::Value(Var, MI->getOperand(0).getImm());
1189 if (MI->getOperand(0).isFPImm())
1190 return DebugLocEntry::Value(Var, MI->getOperand(0).getFPImm());
1191 if (MI->getOperand(0).isCImm())
1192 return DebugLocEntry::Value(Var, MI->getOperand(0).getCImm());
1194 llvm_unreachable("Unexpected 3 operand DBG_VALUE instruction!");
1195 }
1197 /// Determine whether two variable pieces overlap.
1198 static bool piecesOverlap(DIVariable P1, DIVariable P2) {
1199 if (!P1.isVariablePiece() || !P2.isVariablePiece())
1200 return true;
1201 unsigned l1 = P1.getPieceOffset();
1202 unsigned l2 = P2.getPieceOffset();
1203 unsigned r1 = l1 + P1.getPieceSize();
1204 unsigned r2 = l2 + P2.getPieceSize();
1205 // True where [l1,r1[ and [r1,r2[ overlap.
1206 return (l1 < r2) && (l2 < r1);
1207 }
1209 /// Build the location list for all DBG_VALUEs in the function that
1210 /// describe the same variable. If the ranges of several independent
1211 /// pieces of the same variable overlap partially, split them up and
1212 /// combine the ranges. The resulting DebugLocEntries are will have
1213 /// strict monotonically increasing begin addresses and will never
1214 /// overlap.
1215 //
1216 // Input:
1217 //
1218 // Ranges History [var, loc, piece ofs size]
1219 // 0 | [x, (reg0, piece 0, 32)]
1220 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
1221 // 2 | | ...
1222 // 3 | [clobber reg0]
1223 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
1224 //
1225 // Output:
1226 //
1227 // [0-1] [x, (reg0, piece 0, 32)]
1228 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
1229 // [3-4] [x, (reg1, piece 32, 32)]
1230 // [4- ] [x, (mem, piece 0, 64)]
1231 void DwarfDebug::
1232 buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
1233 const DbgValueHistoryMap::InstrRanges &Ranges,
1234 DwarfCompileUnit *TheCU) {
1235 typedef std::pair<DIVariable, DebugLocEntry::Value> Range;
1236 SmallVector<Range, 4> OpenRanges;
1238 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1239 const MachineInstr *Begin = I->first;
1240 const MachineInstr *End = I->second;
1241 assert(Begin->isDebugValue() && "Invalid History entry");
1243 // Check if a variable is inaccessible in this range.
1244 if (!Begin->isDebugValue() ||
1245 (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
1246 !Begin->getOperand(0).getReg())) {
1247 OpenRanges.clear();
1248 continue;
1249 }
1251 // If this piece overlaps with any open ranges, truncate them.
1252 DIVariable DIVar = Begin->getDebugVariable();
1253 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(), [&](Range R){
1254 return piecesOverlap(DIVar, R.first);
1255 });
1256 OpenRanges.erase(Last, OpenRanges.end());
1258 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
1259 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
1261 const MCSymbol *EndLabel;
1262 if (End != nullptr)
1263 EndLabel = getLabelAfterInsn(End);
1264 else if (std::next(I) == Ranges.end())
1265 EndLabel = FunctionEndSym;
1266 else
1267 EndLabel = getLabelBeforeInsn(std::next(I)->first);
1268 assert(EndLabel && "Forgot label after instruction ending a range!");
1270 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
1272 auto Value = getDebugLocValue(Begin);
1273 DebugLocEntry Loc(StartLabel, EndLabel, Value, TheCU);
1274 if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc)) {
1275 // Add all values from still valid non-overlapping pieces.
1276 for (auto Range : OpenRanges)
1277 Loc.addValue(Range.second);
1278 DebugLoc.push_back(std::move(Loc));
1279 }
1280 // Add this value to the list of open ranges.
1281 if (DIVar.isVariablePiece())
1282 OpenRanges.push_back({DIVar, Value});
1284 DEBUG(dbgs() << "Values:\n";
1285 for (auto Value : DebugLoc.back().getValues())
1286 Value.getVariable()->dump();
1287 dbgs() << "-----\n");
1288 }
1289 }
1292 // Find variables for each lexical scope.
1293 void
1294 DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
1295 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1296 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1298 // Grab the variable info that was squirreled away in the MMI side-table.
1299 collectVariableInfoFromMMITable(Processed);
1301 for (const auto &I : DbgValues) {
1302 DIVariable DV(I.first);
1303 if (Processed.count(DV))
1304 continue;
1306 // Instruction ranges, specifying where DV is accessible.
1307 const auto &Ranges = I.second;
1308 if (Ranges.empty())
1309 continue;
1311 LexicalScope *Scope = nullptr;
1312 if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
1313 DISubprogram(DV.getContext()).describes(CurFn->getFunction()))
1314 Scope = LScopes.getCurrentFunctionScope();
1315 else if (MDNode *IA = DV.getInlinedAt()) {
1316 DebugLoc DL = DebugLoc::getFromDILocation(IA);
1317 Scope = LScopes.findInlinedScope(DebugLoc::get(
1318 DL.getLine(), DL.getCol(), DV.getContext(), IA));
1319 } else
1320 Scope = LScopes.findLexicalScope(DV.getContext());
1321 // If variable scope is not found then skip this variable.
1322 if (!Scope)
1323 continue;
1325 Processed.insert(getEntireVariable(DV));
1326 const MachineInstr *MInsn = Ranges.front().first;
1327 assert(MInsn->isDebugValue() && "History must begin with debug value");
1328 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1329 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
1330 DbgVariable *RegVar = ConcreteVariables.back().get();
1331 addScopeVariable(Scope, RegVar);
1333 // Check if the first DBG_VALUE is valid for the rest of the function.
1334 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
1335 continue;
1337 // Handle multiple DBG_VALUE instructions describing one variable.
1338 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
1340 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
1341 DebugLocList &LocList = DotDebugLocEntries.back();
1342 LocList.Label =
1343 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
1345 // Build the location list for this variable.
1346 buildLocationList(LocList.List, Ranges, TheCU);
1347 }
1349 // Collect info for variables that were optimized out.
1350 DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
1351 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1352 DIVariable DV(Variables.getElement(i));
1353 assert(DV.isVariable());
1354 if (!Processed.insert(DV))
1355 continue;
1356 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
1357 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
1358 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
1359 addScopeVariable(Scope, ConcreteVariables.back().get());
1360 }
1361 }
1362 }
1364 // Return Label preceding the instruction.
1365 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1366 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1367 assert(Label && "Didn't insert label before instruction");
1368 return Label;
1369 }
1371 // Return Label immediately following the instruction.
1372 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1373 return LabelsAfterInsn.lookup(MI);
1374 }
1376 // Process beginning of an instruction.
1377 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1378 assert(CurMI == nullptr);
1379 CurMI = MI;
1380 // Check if source location changes, but ignore DBG_VALUE locations.
1381 if (!MI->isDebugValue()) {
1382 DebugLoc DL = MI->getDebugLoc();
1383 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1384 unsigned Flags = 0;
1385 PrevInstLoc = DL;
1386 if (DL == PrologEndLoc) {
1387 Flags |= DWARF2_FLAG_PROLOGUE_END;
1388 PrologEndLoc = DebugLoc();
1389 }
1390 if (PrologEndLoc.isUnknown())
1391 Flags |= DWARF2_FLAG_IS_STMT;
1393 if (!DL.isUnknown()) {
1394 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1395 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1396 } else
1397 recordSourceLine(0, 0, nullptr, 0);
1398 }
1399 }
1401 // Insert labels where requested.
1402 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1403 LabelsBeforeInsn.find(MI);
1405 // No label needed.
1406 if (I == LabelsBeforeInsn.end())
1407 return;
1409 // Label already assigned.
1410 if (I->second)
1411 return;
1413 if (!PrevLabel) {
1414 PrevLabel = MMI->getContext().CreateTempSymbol();
1415 Asm->OutStreamer.EmitLabel(PrevLabel);
1416 }
1417 I->second = PrevLabel;
1418 }
1420 // Process end of an instruction.
1421 void DwarfDebug::endInstruction() {
1422 assert(CurMI != nullptr);
1423 // Don't create a new label after DBG_VALUE instructions.
1424 // They don't generate code.
1425 if (!CurMI->isDebugValue())
1426 PrevLabel = nullptr;
1428 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1429 LabelsAfterInsn.find(CurMI);
1430 CurMI = nullptr;
1432 // No label needed.
1433 if (I == LabelsAfterInsn.end())
1434 return;
1436 // Label already assigned.
1437 if (I->second)
1438 return;
1440 // We need a label after this instruction.
1441 if (!PrevLabel) {
1442 PrevLabel = MMI->getContext().CreateTempSymbol();
1443 Asm->OutStreamer.EmitLabel(PrevLabel);
1444 }
1445 I->second = PrevLabel;
1446 }
1448 // Each LexicalScope has first instruction and last instruction to mark
1449 // beginning and end of a scope respectively. Create an inverse map that list
1450 // scopes starts (and ends) with an instruction. One instruction may start (or
1451 // end) multiple scopes. Ignore scopes that are not reachable.
1452 void DwarfDebug::identifyScopeMarkers() {
1453 SmallVector<LexicalScope *, 4> WorkList;
1454 WorkList.push_back(LScopes.getCurrentFunctionScope());
1455 while (!WorkList.empty()) {
1456 LexicalScope *S = WorkList.pop_back_val();
1458 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1459 if (!Children.empty())
1460 WorkList.append(Children.begin(), Children.end());
1462 if (S->isAbstractScope())
1463 continue;
1465 for (const InsnRange &R : S->getRanges()) {
1466 assert(R.first && "InsnRange does not have first instruction!");
1467 assert(R.second && "InsnRange does not have second instruction!");
1468 requestLabelBeforeInsn(R.first);
1469 requestLabelAfterInsn(R.second);
1470 }
1471 }
1472 }
1474 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1475 // First known non-DBG_VALUE and non-frame setup location marks
1476 // the beginning of the function body.
1477 for (const auto &MBB : *MF)
1478 for (const auto &MI : MBB)
1479 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1480 !MI.getDebugLoc().isUnknown())
1481 return MI.getDebugLoc();
1482 return DebugLoc();
1483 }
1485 // Gather pre-function debug information. Assumes being called immediately
1486 // after the function entry point has been emitted.
1487 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1488 CurFn = MF;
1490 // If there's no debug info for the function we're not going to do anything.
1491 if (!MMI->hasDebugInfo())
1492 return;
1494 auto DI = FunctionDIs.find(MF->getFunction());
1495 if (DI == FunctionDIs.end())
1496 return;
1498 // Grab the lexical scopes for the function, if we don't have any of those
1499 // then we're not going to be able to do anything.
1500 LScopes.initialize(*MF);
1501 if (LScopes.empty())
1502 return;
1504 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1506 // Make sure that each lexical scope will have a begin/end label.
1507 identifyScopeMarkers();
1509 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1510 // belongs to so that we add to the correct per-cu line table in the
1511 // non-asm case.
1512 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1513 // FnScope->getScopeNode() and DI->second should represent the same function,
1514 // though they may not be the same MDNode due to inline functions merged in
1515 // LTO where the debug info metadata still differs (either due to distinct
1516 // written differences - two versions of a linkonce_odr function
1517 // written/copied into two separate files, or some sub-optimal metadata that
1518 // isn't structurally identical (see: file path/name info from clang, which
1519 // includes the directory of the cpp file being built, even when the file name
1520 // is absolute (such as an <> lookup header)))
1521 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1522 assert(TheCU && "Unable to find compile unit!");
1523 if (Asm->OutStreamer.hasRawTextSupport())
1524 // Use a single line table if we are generating assembly.
1525 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1526 else
1527 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1529 // Emit a label for the function so that we have a beginning address.
1530 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1531 // Assumes in correct section after the entry point.
1532 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1534 // Calculate history for local variables.
1535 calculateDbgValueHistory(MF, Asm->TM.getRegisterInfo(), DbgValues);
1537 // Request labels for the full history.
1538 for (const auto &I : DbgValues) {
1539 const auto &Ranges = I.second;
1540 if (Ranges.empty())
1541 continue;
1543 // The first mention of a function argument gets the FunctionBeginSym
1544 // label, so arguments are visible when breaking at function entry.
1545 DIVariable DV(Ranges.front().first->getDebugVariable());
1546 if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
1547 getDISubprogram(DV.getContext()).describes(MF->getFunction())) {
1548 if (!DV.isVariablePiece())
1549 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1550 else {
1551 // Mark all non-overlapping initial pieces.
1552 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1553 DIVariable Piece = I->first->getDebugVariable();
1554 if (std::all_of(Ranges.begin(), I,
1555 [&](DbgValueHistoryMap::InstrRange Pred){
1556 return !piecesOverlap(Piece, Pred.first->getDebugVariable());
1557 }))
1558 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1559 else
1560 break;
1561 }
1562 }
1563 }
1565 for (const auto &Range : Ranges) {
1566 requestLabelBeforeInsn(Range.first);
1567 if (Range.second)
1568 requestLabelAfterInsn(Range.second);
1569 }
1570 }
1572 PrevInstLoc = DebugLoc();
1573 PrevLabel = FunctionBeginSym;
1575 // Record beginning of function.
1576 PrologEndLoc = findPrologueEndLoc(MF);
1577 if (!PrologEndLoc.isUnknown()) {
1578 DebugLoc FnStartDL =
1579 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1580 recordSourceLine(
1581 FnStartDL.getLine(), FnStartDL.getCol(),
1582 FnStartDL.getScope(MF->getFunction()->getContext()),
1583 // We'd like to list the prologue as "not statements" but GDB behaves
1584 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1585 DWARF2_FLAG_IS_STMT);
1586 }
1587 }
1589 void DwarfDebug::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
1590 if (addCurrentFnArgument(Var, LS))
1591 return;
1592 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
1593 DIVariable DV = Var->getVariable();
1594 // Variables with positive arg numbers are parameters.
1595 if (unsigned ArgNum = DV.getArgNumber()) {
1596 // Keep all parameters in order at the start of the variable list to ensure
1597 // function types are correct (no out-of-order parameters)
1598 //
1599 // This could be improved by only doing it for optimized builds (unoptimized
1600 // builds have the right order to begin with), searching from the back (this
1601 // would catch the unoptimized case quickly), or doing a binary search
1602 // rather than linear search.
1603 SmallVectorImpl<DbgVariable *>::iterator I = Vars.begin();
1604 while (I != Vars.end()) {
1605 unsigned CurNum = (*I)->getVariable().getArgNumber();
1606 // A local (non-parameter) variable has been found, insert immediately
1607 // before it.
1608 if (CurNum == 0)
1609 break;
1610 // A later indexed parameter has been found, insert immediately before it.
1611 if (CurNum > ArgNum)
1612 break;
1613 ++I;
1614 }
1615 Vars.insert(I, Var);
1616 return;
1617 }
1619 Vars.push_back(Var);
1620 }
1622 // Gather and emit post-function debug information.
1623 void DwarfDebug::endFunction(const MachineFunction *MF) {
1624 // Every beginFunction(MF) call should be followed by an endFunction(MF) call,
1625 // though the beginFunction may not be called at all.
1626 // We should handle both cases.
1627 if (!CurFn)
1628 CurFn = MF;
1629 else
1630 assert(CurFn == MF);
1631 assert(CurFn != nullptr);
1633 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1634 !FunctionDIs.count(MF->getFunction())) {
1635 // If we don't have a lexical scope for this function then there will
1636 // be a hole in the range information. Keep note of this by setting the
1637 // previously used section to nullptr.
1638 PrevSection = nullptr;
1639 PrevCU = nullptr;
1640 CurFn = nullptr;
1641 return;
1642 }
1644 // Define end label for subprogram.
1645 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1646 // Assumes in correct section after the entry point.
1647 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1649 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1650 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1652 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1653 collectVariableInfo(ProcessedVars);
1655 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1656 DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
1658 // Construct abstract scopes.
1659 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1660 DISubprogram SP(AScope->getScopeNode());
1661 assert(SP.isSubprogram());
1662 // Collect info for variables that were optimized out.
1663 DIArray Variables = SP.getVariables();
1664 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1665 DIVariable DV(Variables.getElement(i));
1666 assert(DV && DV.isVariable());
1667 if (!ProcessedVars.insert(DV))
1668 continue;
1669 ensureAbstractVariableIsCreated(DV, DV.getContext());
1670 }
1671 constructAbstractSubprogramScopeDIE(TheCU, AScope);
1672 }
1674 DIE &CurFnDIE = constructSubprogramScopeDIE(TheCU, FnScope);
1675 if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
1676 TheCU.addFlag(CurFnDIE, dwarf::DW_AT_APPLE_omit_frame_ptr);
1678 // Add the range of this function to the list of ranges for the CU.
1679 RangeSpan Span(FunctionBeginSym, FunctionEndSym);
1680 TheCU.addRange(std::move(Span));
1681 PrevSection = Asm->getCurrentSection();
1682 PrevCU = &TheCU;
1684 // Clear debug info
1685 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1686 // DbgVariables except those that are also in AbstractVariables (since they
1687 // can be used cross-function)
1688 ScopeVariables.clear();
1689 CurrentFnArguments.clear();
1690 DbgValues.clear();
1691 LabelsBeforeInsn.clear();
1692 LabelsAfterInsn.clear();
1693 PrevLabel = nullptr;
1694 CurFn = nullptr;
1695 }
1697 // Register a source line with debug info. Returns the unique label that was
1698 // emitted and which provides correspondence to the source line list.
1699 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1700 unsigned Flags) {
1701 StringRef Fn;
1702 StringRef Dir;
1703 unsigned Src = 1;
1704 unsigned Discriminator = 0;
1705 if (DIScope Scope = DIScope(S)) {
1706 assert(Scope.isScope());
1707 Fn = Scope.getFilename();
1708 Dir = Scope.getDirectory();
1709 if (Scope.isLexicalBlock())
1710 Discriminator = DILexicalBlock(S).getDiscriminator();
1712 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1713 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1714 .getOrCreateSourceID(Fn, Dir);
1715 }
1716 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1717 Discriminator, Fn);
1718 }
1720 //===----------------------------------------------------------------------===//
1721 // Emit Methods
1722 //===----------------------------------------------------------------------===//
1724 // Emit initial Dwarf sections with a label at the start of each one.
1725 void DwarfDebug::emitSectionLabels() {
1726 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1728 // Dwarf sections base addresses.
1729 DwarfInfoSectionSym =
1730 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1731 if (useSplitDwarf()) {
1732 DwarfInfoDWOSectionSym =
1733 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1734 DwarfTypesDWOSectionSym =
1735 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1736 }
1737 DwarfAbbrevSectionSym =
1738 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1739 if (useSplitDwarf())
1740 DwarfAbbrevDWOSectionSym = emitSectionSym(
1741 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1742 if (GenerateARangeSection)
1743 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1745 DwarfLineSectionSym =
1746 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1747 if (GenerateGnuPubSections) {
1748 DwarfGnuPubNamesSectionSym =
1749 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1750 DwarfGnuPubTypesSectionSym =
1751 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1752 } else if (HasDwarfPubSections) {
1753 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1754 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1755 }
1757 DwarfStrSectionSym =
1758 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1759 if (useSplitDwarf()) {
1760 DwarfStrDWOSectionSym =
1761 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1762 DwarfAddrSectionSym =
1763 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1764 DwarfDebugLocSectionSym =
1765 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1766 } else
1767 DwarfDebugLocSectionSym =
1768 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1769 DwarfDebugRangeSectionSym =
1770 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1771 }
1773 // Recursively emits a debug information entry.
1774 void DwarfDebug::emitDIE(DIE &Die) {
1775 // Get the abbreviation for this DIE.
1776 const DIEAbbrev &Abbrev = Die.getAbbrev();
1778 // Emit the code (index) for the abbreviation.
1779 if (Asm->isVerbose())
1780 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1781 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1782 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1783 dwarf::TagString(Abbrev.getTag()));
1784 Asm->EmitULEB128(Abbrev.getNumber());
1786 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1787 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1789 // Emit the DIE attribute values.
1790 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1791 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1792 dwarf::Form Form = AbbrevData[i].getForm();
1793 assert(Form && "Too many attributes for DIE (check abbreviation)");
1795 if (Asm->isVerbose()) {
1796 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1797 if (Attr == dwarf::DW_AT_accessibility)
1798 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1799 cast<DIEInteger>(Values[i])->getValue()));
1800 }
1802 // Emit an attribute using the defined form.
1803 Values[i]->EmitValue(Asm, Form);
1804 }
1806 // Emit the DIE children if any.
1807 if (Abbrev.hasChildren()) {
1808 for (auto &Child : Die.getChildren())
1809 emitDIE(*Child);
1811 Asm->OutStreamer.AddComment("End Of Children Mark");
1812 Asm->EmitInt8(0);
1813 }
1814 }
1816 // Emit the debug info section.
1817 void DwarfDebug::emitDebugInfo() {
1818 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1820 Holder.emitUnits(this, DwarfAbbrevSectionSym);
1821 }
1823 // Emit the abbreviation section.
1824 void DwarfDebug::emitAbbreviations() {
1825 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1827 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1828 }
1830 // Emit the last address of the section and the end of the line matrix.
1831 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1832 // Define last address of section.
1833 Asm->OutStreamer.AddComment("Extended Op");
1834 Asm->EmitInt8(0);
1836 Asm->OutStreamer.AddComment("Op size");
1837 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1838 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1839 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1841 Asm->OutStreamer.AddComment("Section end label");
1843 Asm->OutStreamer.EmitSymbolValue(
1844 Asm->GetTempSymbol("section_end", SectionEnd),
1845 Asm->getDataLayout().getPointerSize());
1847 // Mark end of matrix.
1848 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1849 Asm->EmitInt8(0);
1850 Asm->EmitInt8(1);
1851 Asm->EmitInt8(1);
1852 }
1854 // Emit visible names into a hashed accelerator table section.
1855 void DwarfDebug::emitAccelNames() {
1856 AccelNames.FinalizeTable(Asm, "Names");
1857 Asm->OutStreamer.SwitchSection(
1858 Asm->getObjFileLowering().getDwarfAccelNamesSection());
1859 MCSymbol *SectionBegin = Asm->GetTempSymbol("names_begin");
1860 Asm->OutStreamer.EmitLabel(SectionBegin);
1862 // Emit the full data.
1863 AccelNames.Emit(Asm, SectionBegin, &InfoHolder);
1864 }
1866 // Emit objective C classes and categories into a hashed accelerator table
1867 // section.
1868 void DwarfDebug::emitAccelObjC() {
1869 AccelObjC.FinalizeTable(Asm, "ObjC");
1870 Asm->OutStreamer.SwitchSection(
1871 Asm->getObjFileLowering().getDwarfAccelObjCSection());
1872 MCSymbol *SectionBegin = Asm->GetTempSymbol("objc_begin");
1873 Asm->OutStreamer.EmitLabel(SectionBegin);
1875 // Emit the full data.
1876 AccelObjC.Emit(Asm, SectionBegin, &InfoHolder);
1877 }
1879 // Emit namespace dies into a hashed accelerator table.
1880 void DwarfDebug::emitAccelNamespaces() {
1881 AccelNamespace.FinalizeTable(Asm, "namespac");
1882 Asm->OutStreamer.SwitchSection(
1883 Asm->getObjFileLowering().getDwarfAccelNamespaceSection());
1884 MCSymbol *SectionBegin = Asm->GetTempSymbol("namespac_begin");
1885 Asm->OutStreamer.EmitLabel(SectionBegin);
1887 // Emit the full data.
1888 AccelNamespace.Emit(Asm, SectionBegin, &InfoHolder);
1889 }
1891 // Emit type dies into a hashed accelerator table.
1892 void DwarfDebug::emitAccelTypes() {
1894 AccelTypes.FinalizeTable(Asm, "types");
1895 Asm->OutStreamer.SwitchSection(
1896 Asm->getObjFileLowering().getDwarfAccelTypesSection());
1897 MCSymbol *SectionBegin = Asm->GetTempSymbol("types_begin");
1898 Asm->OutStreamer.EmitLabel(SectionBegin);
1900 // Emit the full data.
1901 AccelTypes.Emit(Asm, SectionBegin, &InfoHolder);
1902 }
1904 // Public name handling.
1905 // The format for the various pubnames:
1906 //
1907 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1908 // for the DIE that is named.
1909 //
1910 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1911 // into the CU and the index value is computed according to the type of value
1912 // for the DIE that is named.
1913 //
1914 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1915 // it's the offset within the debug_info/debug_types dwo section, however, the
1916 // reference in the pubname header doesn't change.
1918 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
1919 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1920 const DIE *Die) {
1921 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1923 // We could have a specification DIE that has our most of our knowledge,
1924 // look for that now.
1925 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1926 if (SpecVal) {
1927 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1928 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1929 Linkage = dwarf::GIEL_EXTERNAL;
1930 } else if (Die->findAttribute(dwarf::DW_AT_external))
1931 Linkage = dwarf::GIEL_EXTERNAL;
1933 switch (Die->getTag()) {
1934 case dwarf::DW_TAG_class_type:
1935 case dwarf::DW_TAG_structure_type:
1936 case dwarf::DW_TAG_union_type:
1937 case dwarf::DW_TAG_enumeration_type:
1938 return dwarf::PubIndexEntryDescriptor(
1939 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1940 ? dwarf::GIEL_STATIC
1941 : dwarf::GIEL_EXTERNAL);
1942 case dwarf::DW_TAG_typedef:
1943 case dwarf::DW_TAG_base_type:
1944 case dwarf::DW_TAG_subrange_type:
1945 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1946 case dwarf::DW_TAG_namespace:
1947 return dwarf::GIEK_TYPE;
1948 case dwarf::DW_TAG_subprogram:
1949 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1950 case dwarf::DW_TAG_constant:
1951 case dwarf::DW_TAG_variable:
1952 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1953 case dwarf::DW_TAG_enumerator:
1954 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1955 dwarf::GIEL_STATIC);
1956 default:
1957 return dwarf::GIEK_NONE;
1958 }
1959 }
1961 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1962 ///
1963 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1964 const MCSection *PSec =
1965 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1966 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1968 emitDebugPubSection(GnuStyle, PSec, "Names", &DwarfUnit::getGlobalNames);
1969 }
1971 void DwarfDebug::emitDebugPubSection(
1972 bool GnuStyle, const MCSection *PSec, StringRef Name,
1973 const StringMap<const DIE *> &(DwarfUnit::*Accessor)() const) {
1974 for (const auto &NU : CUMap) {
1975 DwarfCompileUnit *TheU = NU.second;
1977 const auto &Globals = (TheU->*Accessor)();
1979 if (Globals.empty())
1980 continue;
1982 if (auto Skeleton = static_cast<DwarfCompileUnit *>(TheU->getSkeleton()))
1983 TheU = Skeleton;
1984 unsigned ID = TheU->getUniqueID();
1986 // Start the dwarf pubnames section.
1987 Asm->OutStreamer.SwitchSection(PSec);
1989 // Emit the header.
1990 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1991 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1992 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1993 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1995 Asm->OutStreamer.EmitLabel(BeginLabel);
1997 Asm->OutStreamer.AddComment("DWARF Version");
1998 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
2000 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
2001 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
2003 Asm->OutStreamer.AddComment("Compilation Unit Length");
2004 Asm->EmitLabelDifference(TheU->getLabelEnd(), TheU->getLabelBegin(), 4);
2006 // Emit the pubnames for this compilation unit.
2007 for (const auto &GI : Globals) {
2008 const char *Name = GI.getKeyData();
2009 const DIE *Entity = GI.second;
2011 Asm->OutStreamer.AddComment("DIE offset");
2012 Asm->EmitInt32(Entity->getOffset());
2014 if (GnuStyle) {
2015 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
2016 Asm->OutStreamer.AddComment(
2017 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
2018 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
2019 Asm->EmitInt8(Desc.toBits());
2020 }
2022 Asm->OutStreamer.AddComment("External Name");
2023 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
2024 }
2026 Asm->OutStreamer.AddComment("End Mark");
2027 Asm->EmitInt32(0);
2028 Asm->OutStreamer.EmitLabel(EndLabel);
2029 }
2030 }
2032 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
2033 const MCSection *PSec =
2034 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
2035 : Asm->getObjFileLowering().getDwarfPubTypesSection();
2037 emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
2038 }
2040 // Emit visible names into a debug str section.
2041 void DwarfDebug::emitDebugStr() {
2042 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
2043 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
2044 }
2046 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
2047 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
2048 const DITypeIdentifierMap &Map,
2049 ArrayRef<DebugLocEntry::Value> Values) {
2050 typedef DebugLocEntry::Value Piece;
2051 SmallVector<Piece, 4> Pieces(Values.begin(), Values.end());
2052 assert(std::all_of(Pieces.begin(), Pieces.end(), [](Piece &P) {
2053 return DIVariable(P.getVariable()).isVariablePiece();
2054 }) && "all values are expected to be pieces");
2056 // Sort the pieces so they can be emitted using DW_OP_piece.
2057 std::sort(Pieces.begin(), Pieces.end(), [](const Piece &A, const Piece &B) {
2058 DIVariable VarA(A.getVariable());
2059 DIVariable VarB(B.getVariable());
2060 return VarA.getPieceOffset() < VarB.getPieceOffset();
2061 });
2062 // Remove any duplicate entries by dropping all but the first.
2063 Pieces.erase(std::unique(Pieces.begin(), Pieces.end(),
2064 [] (const Piece &A,const Piece &B){
2065 return A.getVariable() == B.getVariable();
2066 }), Pieces.end());
2068 unsigned Offset = 0;
2069 for (auto Piece : Pieces) {
2070 DIVariable Var(Piece.getVariable());
2071 unsigned PieceOffset = Var.getPieceOffset();
2072 unsigned PieceSize = Var.getPieceSize();
2073 assert(Offset <= PieceOffset && "overlapping pieces in DebugLocEntry");
2074 if (Offset < PieceOffset) {
2075 // The DWARF spec seriously mandates pieces with no locations for gaps.
2076 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
2077 Offset += PieceOffset-Offset;
2078 }
2080 Offset += PieceSize;
2082 const unsigned SizeOfByte = 8;
2083 assert(!Var.isIndirect() && "indirect address for piece");
2084 #ifndef NDEBUG
2085 unsigned VarSize = Var.getSizeInBits(Map);
2086 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
2087 && "piece is larger than or outside of variable");
2088 assert(PieceSize*SizeOfByte != VarSize
2089 && "piece covers entire variable");
2090 #endif
2091 if (Piece.isLocation() && Piece.getLoc().isReg())
2092 Asm->EmitDwarfRegOpPiece(Streamer,
2093 Piece.getLoc(),
2094 PieceSize*SizeOfByte);
2095 else {
2096 emitDebugLocValue(Streamer, Piece);
2097 Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
2098 }
2099 }
2100 }
2103 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
2104 const DebugLocEntry &Entry) {
2105 const DebugLocEntry::Value Value = Entry.getValues()[0];
2106 DIVariable DV(Value.getVariable());
2107 if (DV.isVariablePiece())
2108 // Emit all pieces that belong to the same variable and range.
2109 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
2111 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
2112 emitDebugLocValue(Streamer, Value);
2113 }
2115 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
2116 const DebugLocEntry::Value &Value) {
2117 DIVariable DV(Value.getVariable());
2118 // Regular entry.
2119 if (Value.isInt()) {
2120 DIBasicType BTy(resolve(DV.getType()));
2121 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
2122 BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
2123 Streamer.EmitInt8(dwarf::DW_OP_consts, "DW_OP_consts");
2124 Streamer.EmitSLEB128(Value.getInt());
2125 } else {
2126 Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
2127 Streamer.EmitULEB128(Value.getInt());
2128 }
2129 } else if (Value.isLocation()) {
2130 MachineLocation Loc = Value.getLoc();
2131 if (!DV.hasComplexAddress())
2132 // Regular entry.
2133 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2134 else {
2135 // Complex address entry.
2136 unsigned N = DV.getNumAddrElements();
2137 unsigned i = 0;
2138 if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
2139 if (Loc.getOffset()) {
2140 i = 2;
2141 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2142 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2143 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2144 Streamer.EmitSLEB128(DV.getAddrElement(1));
2145 } else {
2146 // If first address element is OpPlus then emit
2147 // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
2148 MachineLocation TLoc(Loc.getReg(), DV.getAddrElement(1));
2149 Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
2150 i = 2;
2151 }
2152 } else {
2153 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
2154 }
2156 // Emit remaining complex address elements.
2157 for (; i < N; ++i) {
2158 uint64_t Element = DV.getAddrElement(i);
2159 if (Element == DIBuilder::OpPlus) {
2160 Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
2161 Streamer.EmitULEB128(DV.getAddrElement(++i));
2162 } else if (Element == DIBuilder::OpDeref) {
2163 if (!Loc.isReg())
2164 Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
2165 } else if (Element == DIBuilder::OpPiece) {
2166 i += 3;
2167 // handled in emitDebugLocEntry.
2168 } else
2169 llvm_unreachable("unknown Opcode found in complex address");
2170 }
2171 }
2172 }
2173 // else ... ignore constant fp. There is not any good way to
2174 // to represent them here in dwarf.
2175 // FIXME: ^
2176 }
2178 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
2179 Asm->OutStreamer.AddComment("Loc expr size");
2180 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
2181 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
2182 Asm->EmitLabelDifference(end, begin, 2);
2183 Asm->OutStreamer.EmitLabel(begin);
2184 // Emit the entry.
2185 APByteStreamer Streamer(*Asm);
2186 emitDebugLocEntry(Streamer, Entry);
2187 // Close the range.
2188 Asm->OutStreamer.EmitLabel(end);
2189 }
2191 // Emit locations into the debug loc section.
2192 void DwarfDebug::emitDebugLoc() {
2193 // Start the dwarf loc section.
2194 Asm->OutStreamer.SwitchSection(
2195 Asm->getObjFileLowering().getDwarfLocSection());
2196 unsigned char Size = Asm->getDataLayout().getPointerSize();
2197 for (const auto &DebugLoc : DotDebugLocEntries) {
2198 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2199 for (const auto &Entry : DebugLoc.List) {
2200 // Set up the range. This range is relative to the entry point of the
2201 // compile unit. This is a hard coded 0 for low_pc when we're emitting
2202 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
2203 const DwarfCompileUnit *CU = Entry.getCU();
2204 if (CU->getRanges().size() == 1) {
2205 // Grab the begin symbol from the first range as our base.
2206 const MCSymbol *Base = CU->getRanges()[0].getStart();
2207 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
2208 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
2209 } else {
2210 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
2211 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
2212 }
2214 emitDebugLocEntryLocation(Entry);
2215 }
2216 Asm->OutStreamer.EmitIntValue(0, Size);
2217 Asm->OutStreamer.EmitIntValue(0, Size);
2218 }
2219 }
2221 void DwarfDebug::emitDebugLocDWO() {
2222 Asm->OutStreamer.SwitchSection(
2223 Asm->getObjFileLowering().getDwarfLocDWOSection());
2224 for (const auto &DebugLoc : DotDebugLocEntries) {
2225 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
2226 for (const auto &Entry : DebugLoc.List) {
2227 // Just always use start_length for now - at least that's one address
2228 // rather than two. We could get fancier and try to, say, reuse an
2229 // address we know we've emitted elsewhere (the start of the function?
2230 // The start of the CU or CU subrange that encloses this range?)
2231 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
2232 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
2233 Asm->EmitULEB128(idx);
2234 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
2236 emitDebugLocEntryLocation(Entry);
2237 }
2238 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
2239 }
2240 }
2242 struct ArangeSpan {
2243 const MCSymbol *Start, *End;
2244 };
2246 // Emit a debug aranges section, containing a CU lookup for any
2247 // address we can tie back to a CU.
2248 void DwarfDebug::emitDebugARanges() {
2249 // Start the dwarf aranges section.
2250 Asm->OutStreamer.SwitchSection(
2251 Asm->getObjFileLowering().getDwarfARangesSection());
2253 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
2255 SpansType Spans;
2257 // Build a list of sections used.
2258 std::vector<const MCSection *> Sections;
2259 for (const auto &it : SectionMap) {
2260 const MCSection *Section = it.first;
2261 Sections.push_back(Section);
2262 }
2264 // Sort the sections into order.
2265 // This is only done to ensure consistent output order across different runs.
2266 std::sort(Sections.begin(), Sections.end(), SectionSort);
2268 // Build a set of address spans, sorted by CU.
2269 for (const MCSection *Section : Sections) {
2270 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
2271 if (List.size() < 2)
2272 continue;
2274 // Sort the symbols by offset within the section.
2275 std::sort(List.begin(), List.end(),
2276 [&](const SymbolCU &A, const SymbolCU &B) {
2277 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
2278 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
2280 // Symbols with no order assigned should be placed at the end.
2281 // (e.g. section end labels)
2282 if (IA == 0)
2283 return false;
2284 if (IB == 0)
2285 return true;
2286 return IA < IB;
2287 });
2289 // If we have no section (e.g. common), just write out
2290 // individual spans for each symbol.
2291 if (!Section) {
2292 for (const SymbolCU &Cur : List) {
2293 ArangeSpan Span;
2294 Span.Start = Cur.Sym;
2295 Span.End = nullptr;
2296 if (Cur.CU)
2297 Spans[Cur.CU].push_back(Span);
2298 }
2299 } else {
2300 // Build spans between each label.
2301 const MCSymbol *StartSym = List[0].Sym;
2302 for (size_t n = 1, e = List.size(); n < e; n++) {
2303 const SymbolCU &Prev = List[n - 1];
2304 const SymbolCU &Cur = List[n];
2306 // Try and build the longest span we can within the same CU.
2307 if (Cur.CU != Prev.CU) {
2308 ArangeSpan Span;
2309 Span.Start = StartSym;
2310 Span.End = Cur.Sym;
2311 Spans[Prev.CU].push_back(Span);
2312 StartSym = Cur.Sym;
2313 }
2314 }
2315 }
2316 }
2318 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
2320 // Build a list of CUs used.
2321 std::vector<DwarfCompileUnit *> CUs;
2322 for (const auto &it : Spans) {
2323 DwarfCompileUnit *CU = it.first;
2324 CUs.push_back(CU);
2325 }
2327 // Sort the CU list (again, to ensure consistent output order).
2328 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
2329 return A->getUniqueID() < B->getUniqueID();
2330 });
2332 // Emit an arange table for each CU we used.
2333 for (DwarfCompileUnit *CU : CUs) {
2334 std::vector<ArangeSpan> &List = Spans[CU];
2336 // Emit size of content not including length itself.
2337 unsigned ContentSize =
2338 sizeof(int16_t) + // DWARF ARange version number
2339 sizeof(int32_t) + // Offset of CU in the .debug_info section
2340 sizeof(int8_t) + // Pointer Size (in bytes)
2341 sizeof(int8_t); // Segment Size (in bytes)
2343 unsigned TupleSize = PtrSize * 2;
2345 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
2346 unsigned Padding =
2347 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
2349 ContentSize += Padding;
2350 ContentSize += (List.size() + 1) * TupleSize;
2352 // For each compile unit, write the list of spans it covers.
2353 Asm->OutStreamer.AddComment("Length of ARange Set");
2354 Asm->EmitInt32(ContentSize);
2355 Asm->OutStreamer.AddComment("DWARF Arange version number");
2356 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
2357 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
2358 Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
2359 Asm->OutStreamer.AddComment("Address Size (in bytes)");
2360 Asm->EmitInt8(PtrSize);
2361 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
2362 Asm->EmitInt8(0);
2364 Asm->OutStreamer.EmitFill(Padding, 0xff);
2366 for (const ArangeSpan &Span : List) {
2367 Asm->EmitLabelReference(Span.Start, PtrSize);
2369 // Calculate the size as being from the span start to it's end.
2370 if (Span.End) {
2371 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
2372 } else {
2373 // For symbols without an end marker (e.g. common), we
2374 // write a single arange entry containing just that one symbol.
2375 uint64_t Size = SymSize[Span.Start];
2376 if (Size == 0)
2377 Size = 1;
2379 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
2380 }
2381 }
2383 Asm->OutStreamer.AddComment("ARange terminator");
2384 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2385 Asm->OutStreamer.EmitIntValue(0, PtrSize);
2386 }
2387 }
2389 // Emit visible names into a debug ranges section.
2390 void DwarfDebug::emitDebugRanges() {
2391 // Start the dwarf ranges section.
2392 Asm->OutStreamer.SwitchSection(
2393 Asm->getObjFileLowering().getDwarfRangesSection());
2395 // Size for our labels.
2396 unsigned char Size = Asm->getDataLayout().getPointerSize();
2398 // Grab the specific ranges for the compile units in the module.
2399 for (const auto &I : CUMap) {
2400 DwarfCompileUnit *TheCU = I.second;
2402 // Iterate over the misc ranges for the compile units in the module.
2403 for (const RangeSpanList &List : TheCU->getRangeLists()) {
2404 // Emit our symbol so we can find the beginning of the range.
2405 Asm->OutStreamer.EmitLabel(List.getSym());
2407 for (const RangeSpan &Range : List.getRanges()) {
2408 const MCSymbol *Begin = Range.getStart();
2409 const MCSymbol *End = Range.getEnd();
2410 assert(Begin && "Range without a begin symbol?");
2411 assert(End && "Range without an end symbol?");
2412 if (TheCU->getRanges().size() == 1) {
2413 // Grab the begin symbol from the first range as our base.
2414 const MCSymbol *Base = TheCU->getRanges()[0].getStart();
2415 Asm->EmitLabelDifference(Begin, Base, Size);
2416 Asm->EmitLabelDifference(End, Base, Size);
2417 } else {
2418 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2419 Asm->OutStreamer.EmitSymbolValue(End, Size);
2420 }
2421 }
2423 // And terminate the list with two 0 values.
2424 Asm->OutStreamer.EmitIntValue(0, Size);
2425 Asm->OutStreamer.EmitIntValue(0, Size);
2426 }
2428 // Now emit a range for the CU itself.
2429 if (TheCU->getRanges().size() > 1) {
2430 Asm->OutStreamer.EmitLabel(
2431 Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
2432 for (const RangeSpan &Range : TheCU->getRanges()) {
2433 const MCSymbol *Begin = Range.getStart();
2434 const MCSymbol *End = Range.getEnd();
2435 assert(Begin && "Range without a begin symbol?");
2436 assert(End && "Range without an end symbol?");
2437 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
2438 Asm->OutStreamer.EmitSymbolValue(End, Size);
2439 }
2440 // And terminate the list with two 0 values.
2441 Asm->OutStreamer.EmitIntValue(0, Size);
2442 Asm->OutStreamer.EmitIntValue(0, Size);
2443 }
2444 }
2445 }
2447 // DWARF5 Experimental Separate Dwarf emitters.
2449 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2450 std::unique_ptr<DwarfUnit> NewU) {
2451 NewU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
2452 U.getCUNode().getSplitDebugFilename());
2454 if (!CompilationDir.empty())
2455 NewU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2457 addGnuPubAttributes(*NewU, Die);
2459 SkeletonHolder.addUnit(std::move(NewU));
2460 }
2462 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2463 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2464 // DW_AT_addr_base, DW_AT_ranges_base.
2465 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2467 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2468 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2469 DwarfCompileUnit &NewCU = *OwnedUnit;
2470 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2471 DwarfInfoSectionSym);
2473 NewCU.initStmtList(DwarfLineSectionSym);
2475 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2477 return NewCU;
2478 }
2480 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_dwo_name,
2481 // DW_AT_addr_base.
2482 DwarfTypeUnit &DwarfDebug::constructSkeletonTU(DwarfTypeUnit &TU) {
2483 DwarfCompileUnit &CU = static_cast<DwarfCompileUnit &>(
2484 *SkeletonHolder.getUnits()[TU.getCU().getUniqueID()]);
2486 auto OwnedUnit = make_unique<DwarfTypeUnit>(TU.getUniqueID(), CU, Asm, this,
2487 &SkeletonHolder);
2488 DwarfTypeUnit &NewTU = *OwnedUnit;
2489 NewTU.setTypeSignature(TU.getTypeSignature());
2490 NewTU.setType(nullptr);
2491 NewTU.initSection(
2492 Asm->getObjFileLowering().getDwarfTypesSection(TU.getTypeSignature()));
2494 initSkeletonUnit(TU, NewTU.getUnitDie(), std::move(OwnedUnit));
2495 return NewTU;
2496 }
2498 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2499 // compile units that would normally be in debug_info.
2500 void DwarfDebug::emitDebugInfoDWO() {
2501 assert(useSplitDwarf() && "No split dwarf debug info?");
2502 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2503 // emit relocations into the dwo file.
2504 InfoHolder.emitUnits(this, /* AbbrevSymbol */ nullptr);
2505 }
2507 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2508 // abbreviations for the .debug_info.dwo section.
2509 void DwarfDebug::emitDebugAbbrevDWO() {
2510 assert(useSplitDwarf() && "No split dwarf?");
2511 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2512 }
2514 void DwarfDebug::emitDebugLineDWO() {
2515 assert(useSplitDwarf() && "No split dwarf?");
2516 Asm->OutStreamer.SwitchSection(
2517 Asm->getObjFileLowering().getDwarfLineDWOSection());
2518 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2519 }
2521 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2522 // string section and is identical in format to traditional .debug_str
2523 // sections.
2524 void DwarfDebug::emitDebugStrDWO() {
2525 assert(useSplitDwarf() && "No split dwarf?");
2526 const MCSection *OffSec =
2527 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2528 const MCSymbol *StrSym = DwarfStrSectionSym;
2529 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2530 OffSec, StrSym);
2531 }
2533 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2534 if (!useSplitDwarf())
2535 return nullptr;
2536 if (SingleCU)
2537 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2538 return &SplitTypeUnitFileTable;
2539 }
2541 static uint64_t makeTypeSignature(StringRef Identifier) {
2542 MD5 Hash;
2543 Hash.update(Identifier);
2544 // ... take the least significant 8 bytes and return those. Our MD5
2545 // implementation always returns its results in little endian, swap bytes
2546 // appropriately.
2547 MD5::MD5Result Result;
2548 Hash.final(Result);
2549 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2550 }
2552 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2553 StringRef Identifier, DIE &RefDie,
2554 DICompositeType CTy) {
2555 // Fast path if we're building some type units and one has already used the
2556 // address pool we know we're going to throw away all this work anyway, so
2557 // don't bother building dependent types.
2558 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2559 return;
2561 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2562 if (TU) {
2563 CU.addDIETypeSignature(RefDie, *TU);
2564 return;
2565 }
2567 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2568 AddrPool.resetUsedFlag();
2570 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2571 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2572 this, &InfoHolder, getDwoLineTable(CU));
2573 DwarfTypeUnit &NewTU = *OwnedUnit;
2574 DIE &UnitDie = NewTU.getUnitDie();
2575 TU = &NewTU;
2576 TypeUnitsUnderConstruction.push_back(
2577 std::make_pair(std::move(OwnedUnit), CTy));
2579 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2580 CU.getLanguage());
2582 uint64_t Signature = makeTypeSignature(Identifier);
2583 NewTU.setTypeSignature(Signature);
2585 if (useSplitDwarf())
2586 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
2587 DwarfTypesDWOSectionSym);
2588 else {
2589 CU.applyStmtList(UnitDie);
2590 NewTU.initSection(
2591 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2592 }
2594 NewTU.setType(NewTU.createTypeDIE(CTy));
2596 if (TopLevelType) {
2597 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2598 TypeUnitsUnderConstruction.clear();
2600 // Types referencing entries in the address table cannot be placed in type
2601 // units.
2602 if (AddrPool.hasBeenUsed()) {
2604 // Remove all the types built while building this type.
2605 // This is pessimistic as some of these types might not be dependent on
2606 // the type that used an address.
2607 for (const auto &TU : TypeUnitsToAdd)
2608 DwarfTypeUnits.erase(TU.second);
2610 // Construct this type in the CU directly.
2611 // This is inefficient because all the dependent types will be rebuilt
2612 // from scratch, including building them in type units, discovering that
2613 // they depend on addresses, throwing them out and rebuilding them.
2614 CU.constructTypeDIE(RefDie, CTy);
2615 return;
2616 }
2618 // If the type wasn't dependent on fission addresses, finish adding the type
2619 // and all its dependent types.
2620 for (auto &TU : TypeUnitsToAdd) {
2621 if (useSplitDwarf())
2622 TU.first->setSkeleton(constructSkeletonTU(*TU.first));
2623 InfoHolder.addUnit(std::move(TU.first));
2624 }
2625 }
2626 CU.addDIETypeSignature(RefDie, NewTU);
2627 }
2629 void DwarfDebug::attachLowHighPC(DwarfCompileUnit &Unit, DIE &D,
2630 MCSymbol *Begin, 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 }