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 //===----------------------------------------------------------------------===//
13
14 #include "DwarfDebug.h"
15 #include "ByteStreamer.h"
16 #include "DIEHash.h"
17 #include "DwarfCompileUnit.h"
18 #include "DwarfExpression.h"
19 #include "DwarfUnit.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/CodeGen/DIE.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DIBuilder.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/Instructions.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/ValueHandle.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSection.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/Dwarf.h"
41 #include "llvm/Support/Endian.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/FormattedStream.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MD5.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Target/TargetFrameLowering.h"
49 #include "llvm/Target/TargetLoweringObjectFile.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Target/TargetRegisterInfo.h"
53 #include "llvm/Target/TargetSubtargetInfo.h"
54 using namespace llvm;
55
56 #define DEBUG_TYPE "dwarfdebug"
57
58 static cl::opt<bool>
59 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
60 cl::desc("Disable debug info printing"));
61
62 static cl::opt<bool> UnknownLocations(
63 "use-unknown-locations", cl::Hidden,
64 cl::desc("Make an absence of debug location information explicit."),
65 cl::init(false));
66
67 static cl::opt<bool>
68 GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
69 cl::desc("Generate GNU-style pubnames and pubtypes"),
70 cl::init(false));
71
72 static cl::opt<bool> GenerateARangeSection("generate-arange-section",
73 cl::Hidden,
74 cl::desc("Generate dwarf aranges"),
75 cl::init(false));
76
77 namespace {
78 enum DefaultOnOff { Default, Enable, Disable };
79 }
80
81 static cl::opt<DefaultOnOff>
82 DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
83 cl::desc("Output prototype dwarf accelerator tables."),
84 cl::values(clEnumVal(Default, "Default for platform"),
85 clEnumVal(Enable, "Enabled"),
86 clEnumVal(Disable, "Disabled"), clEnumValEnd),
87 cl::init(Default));
88
89 static cl::opt<DefaultOnOff>
90 SplitDwarf("split-dwarf", cl::Hidden,
91 cl::desc("Output DWARF5 split debug info."),
92 cl::values(clEnumVal(Default, "Default for platform"),
93 clEnumVal(Enable, "Enabled"),
94 clEnumVal(Disable, "Disabled"), clEnumValEnd),
95 cl::init(Default));
96
97 static cl::opt<DefaultOnOff>
98 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
99 cl::desc("Generate DWARF pubnames and pubtypes sections"),
100 cl::values(clEnumVal(Default, "Default for platform"),
101 clEnumVal(Enable, "Enabled"),
102 clEnumVal(Disable, "Disabled"), clEnumValEnd),
103 cl::init(Default));
104
105 static const char *const DWARFGroupName = "DWARF Emission";
106 static const char *const DbgTimerName = "DWARF Debug Writer";
107
108 //===----------------------------------------------------------------------===//
109
110 /// resolve - Look in the DwarfDebug map for the MDNode that
111 /// corresponds to the reference.
resolve(DIRef<T> Ref) const112 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
113 return DD->resolve(Ref);
114 }
115
isBlockByrefVariable() const116 bool DbgVariable::isBlockByrefVariable() const {
117 assert(Var.isVariable() && "Invalid complex DbgVariable!");
118 return Var.isBlockByrefVariable(DD->getTypeIdentifierMap());
119 }
120
getType() const121 DIType DbgVariable::getType() const {
122 DIType Ty = Var.getType().resolve(DD->getTypeIdentifierMap());
123 // FIXME: isBlockByrefVariable should be reformulated in terms of complex
124 // addresses instead.
125 if (Var.isBlockByrefVariable(DD->getTypeIdentifierMap())) {
126 /* Byref variables, in Blocks, are declared by the programmer as
127 "SomeType VarName;", but the compiler creates a
128 __Block_byref_x_VarName struct, and gives the variable VarName
129 either the struct, or a pointer to the struct, as its type. This
130 is necessary for various behind-the-scenes things the compiler
131 needs to do with by-reference variables in blocks.
132
133 However, as far as the original *programmer* is concerned, the
134 variable should still have type 'SomeType', as originally declared.
135
136 The following function dives into the __Block_byref_x_VarName
137 struct to find the original type of the variable. This will be
138 passed back to the code generating the type for the Debug
139 Information Entry for the variable 'VarName'. 'VarName' will then
140 have the original type 'SomeType' in its debug information.
141
142 The original type 'SomeType' will be the type of the field named
143 'VarName' inside the __Block_byref_x_VarName struct.
144
145 NOTE: In order for this to not completely fail on the debugger
146 side, the Debug Information Entry for the variable VarName needs to
147 have a DW_AT_location that tells the debugger how to unwind through
148 the pointers and __Block_byref_x_VarName struct to find the actual
149 value of the variable. The function addBlockByrefType does this. */
150 DIType subType = Ty;
151 uint16_t tag = Ty.getTag();
152
153 if (tag == dwarf::DW_TAG_pointer_type)
154 subType = resolve(DIDerivedType(Ty).getTypeDerivedFrom());
155
156 DIArray Elements = DICompositeType(subType).getElements();
157 for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
158 DIDerivedType DT(Elements.getElement(i));
159 if (getName() == DT.getName())
160 return (resolve(DT.getTypeDerivedFrom()));
161 }
162 }
163 return Ty;
164 }
165
166 static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = {
167 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
168 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
169 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)};
170
DwarfDebug(AsmPrinter * A,Module * M)171 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
172 : Asm(A), MMI(Asm->MMI), PrevLabel(nullptr), GlobalRangeCount(0),
173 InfoHolder(A, *this, "info_string", DIEValueAllocator),
174 UsedNonDefaultText(false),
175 SkeletonHolder(A, *this, "skel_string", DIEValueAllocator),
176 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
177 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
178 dwarf::DW_FORM_data4)),
179 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
180 dwarf::DW_FORM_data4)),
181 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
182 dwarf::DW_FORM_data4)),
183 AccelTypes(TypeAtoms) {
184
185 DwarfInfoSectionSym = DwarfAbbrevSectionSym = DwarfStrSectionSym = nullptr;
186 DwarfDebugRangeSectionSym = DwarfDebugLocSectionSym = nullptr;
187 DwarfLineSectionSym = nullptr;
188 DwarfAddrSectionSym = nullptr;
189 DwarfAbbrevDWOSectionSym = DwarfStrDWOSectionSym = nullptr;
190 FunctionBeginSym = FunctionEndSym = nullptr;
191 CurFn = nullptr;
192 CurMI = nullptr;
193
194 // Turn on accelerator tables for Darwin by default, pubnames by
195 // default for non-Darwin, and handle split dwarf.
196 if (DwarfAccelTables == Default)
197 HasDwarfAccelTables = IsDarwin;
198 else
199 HasDwarfAccelTables = DwarfAccelTables == Enable;
200
201 if (SplitDwarf == Default)
202 HasSplitDwarf = false;
203 else
204 HasSplitDwarf = SplitDwarf == Enable;
205
206 if (DwarfPubSections == Default)
207 HasDwarfPubSections = !IsDarwin;
208 else
209 HasDwarfPubSections = DwarfPubSections == Enable;
210
211 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion;
212 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
213 : MMI->getModule()->getDwarfVersion();
214
215 Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion);
216
217 {
218 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
219 beginModule();
220 }
221 }
222
223 // Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
~DwarfDebug()224 DwarfDebug::~DwarfDebug() { }
225
226 // Switch to the specified MCSection and emit an assembler
227 // temporary label to it if SymbolStem is specified.
emitSectionSym(AsmPrinter * Asm,const MCSection * Section,const char * SymbolStem=nullptr)228 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
229 const char *SymbolStem = nullptr) {
230 Asm->OutStreamer.SwitchSection(Section);
231 if (!SymbolStem)
232 return nullptr;
233
234 MCSymbol *TmpSym = Asm->GetTempSymbol(SymbolStem);
235 Asm->OutStreamer.EmitLabel(TmpSym);
236 return TmpSym;
237 }
238
isObjCClass(StringRef Name)239 static bool isObjCClass(StringRef Name) {
240 return Name.startswith("+") || Name.startswith("-");
241 }
242
hasObjCCategory(StringRef Name)243 static bool hasObjCCategory(StringRef Name) {
244 if (!isObjCClass(Name))
245 return false;
246
247 return Name.find(") ") != StringRef::npos;
248 }
249
getObjCClassCategory(StringRef In,StringRef & Class,StringRef & Category)250 static void getObjCClassCategory(StringRef In, StringRef &Class,
251 StringRef &Category) {
252 if (!hasObjCCategory(In)) {
253 Class = In.slice(In.find('[') + 1, In.find(' '));
254 Category = "";
255 return;
256 }
257
258 Class = In.slice(In.find('[') + 1, In.find('('));
259 Category = In.slice(In.find('[') + 1, In.find(' '));
260 return;
261 }
262
getObjCMethodName(StringRef In)263 static StringRef getObjCMethodName(StringRef In) {
264 return In.slice(In.find(' ') + 1, In.find(']'));
265 }
266
267 // Helper for sorting sections into a stable output order.
SectionSort(const MCSection * A,const MCSection * B)268 static bool SectionSort(const MCSection *A, const MCSection *B) {
269 std::string LA = (A ? A->getLabelBeginName() : "");
270 std::string LB = (B ? B->getLabelBeginName() : "");
271 return LA < LB;
272 }
273
274 // Add the various names to the Dwarf accelerator table names.
275 // TODO: Determine whether or not we should add names for programs
276 // that do not have a DW_AT_name or DW_AT_linkage_name field - this
277 // is only slightly different than the lookup of non-standard ObjC names.
addSubprogramNames(DISubprogram SP,DIE & Die)278 void DwarfDebug::addSubprogramNames(DISubprogram SP, DIE &Die) {
279 if (!SP.isDefinition())
280 return;
281 addAccelName(SP.getName(), Die);
282
283 // If the linkage name is different than the name, go ahead and output
284 // that as well into the name table.
285 if (SP.getLinkageName() != "" && SP.getName() != SP.getLinkageName())
286 addAccelName(SP.getLinkageName(), Die);
287
288 // If this is an Objective-C selector name add it to the ObjC accelerator
289 // too.
290 if (isObjCClass(SP.getName())) {
291 StringRef Class, Category;
292 getObjCClassCategory(SP.getName(), Class, Category);
293 addAccelObjC(Class, Die);
294 if (Category != "")
295 addAccelObjC(Category, Die);
296 // Also add the base method name to the name table.
297 addAccelName(getObjCMethodName(SP.getName()), Die);
298 }
299 }
300
301 /// isSubprogramContext - Return true if Context is either a subprogram
302 /// or another context nested inside a subprogram.
isSubprogramContext(const MDNode * Context)303 bool DwarfDebug::isSubprogramContext(const MDNode *Context) {
304 if (!Context)
305 return false;
306 DIDescriptor D(Context);
307 if (D.isSubprogram())
308 return true;
309 if (D.isType())
310 return isSubprogramContext(resolve(DIType(Context).getContext()));
311 return false;
312 }
313
314 /// Check whether we should create a DIE for the given Scope, return true
315 /// if we don't create a DIE (the corresponding DIE is null).
isLexicalScopeDIENull(LexicalScope * Scope)316 bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) {
317 if (Scope->isAbstractScope())
318 return false;
319
320 // We don't create a DIE if there is no Range.
321 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
322 if (Ranges.empty())
323 return true;
324
325 if (Ranges.size() > 1)
326 return false;
327
328 // We don't create a DIE if we have a single Range and the end label
329 // is null.
330 return !getLabelAfterInsn(Ranges.front().second);
331 }
332
forBothCUs(DwarfCompileUnit & CU,Func F)333 template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) {
334 F(CU);
335 if (auto *SkelCU = CU.getSkeleton())
336 F(*SkelCU);
337 }
338
constructAbstractSubprogramScopeDIE(LexicalScope * Scope)339 void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
340 assert(Scope && Scope->getScopeNode());
341 assert(Scope->isAbstractScope());
342 assert(!Scope->getInlinedAt());
343
344 const MDNode *SP = Scope->getScopeNode();
345
346 ProcessedSPNodes.insert(SP);
347
348 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
349 // was inlined from another compile unit.
350 auto &CU = SPMap[SP];
351 forBothCUs(*CU, [&](DwarfCompileUnit &CU) {
352 CU.constructAbstractSubprogramScopeDIE(Scope);
353 });
354 }
355
addGnuPubAttributes(DwarfUnit & U,DIE & D) const356 void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
357 if (!GenerateGnuPubSections)
358 return;
359
360 U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
361 }
362
363 // Create new DwarfCompileUnit for the given metadata node with tag
364 // DW_TAG_compile_unit.
constructDwarfCompileUnit(DICompileUnit DIUnit)365 DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
366 StringRef FN = DIUnit.getFilename();
367 CompilationDir = DIUnit.getDirectory();
368
369 auto OwnedUnit = make_unique<DwarfCompileUnit>(
370 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
371 DwarfCompileUnit &NewCU = *OwnedUnit;
372 DIE &Die = NewCU.getUnitDie();
373 InfoHolder.addUnit(std::move(OwnedUnit));
374 if (useSplitDwarf())
375 NewCU.setSkeleton(constructSkeletonCU(NewCU));
376
377 // LTO with assembly output shares a single line table amongst multiple CUs.
378 // To avoid the compilation directory being ambiguous, let the line table
379 // explicitly describe the directory of all files, never relying on the
380 // compilation directory.
381 if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
382 Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
383 NewCU.getUniqueID(), CompilationDir);
384
385 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit.getProducer());
386 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
387 DIUnit.getLanguage());
388 NewCU.addString(Die, dwarf::DW_AT_name, FN);
389
390 if (!useSplitDwarf()) {
391 NewCU.initStmtList(DwarfLineSectionSym);
392
393 // If we're using split dwarf the compilation dir is going to be in the
394 // skeleton CU and so we don't need to duplicate it here.
395 if (!CompilationDir.empty())
396 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
397
398 addGnuPubAttributes(NewCU, Die);
399 }
400
401 if (DIUnit.isOptimized())
402 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized);
403
404 StringRef Flags = DIUnit.getFlags();
405 if (!Flags.empty())
406 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags);
407
408 if (unsigned RVer = DIUnit.getRunTimeVersion())
409 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers,
410 dwarf::DW_FORM_data1, RVer);
411
412 if (useSplitDwarf())
413 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection(),
414 DwarfInfoDWOSectionSym);
415 else
416 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
417 DwarfInfoSectionSym);
418
419 CUMap.insert(std::make_pair(DIUnit, &NewCU));
420 CUDieMap.insert(std::make_pair(&Die, &NewCU));
421 return NewCU;
422 }
423
constructAndAddImportedEntityDIE(DwarfCompileUnit & TheCU,const MDNode * N)424 void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
425 const MDNode *N) {
426 DIImportedEntity Module(N);
427 assert(Module.Verify());
428 if (DIE *D = TheCU.getOrCreateContextDIE(Module.getContext()))
429 D->addChild(TheCU.constructImportedEntityDIE(Module));
430 }
431
432 // Emit all Dwarf sections that should come prior to the content. Create
433 // global DIEs and emit initial debug info sections. This is invoked by
434 // the target AsmPrinter.
beginModule()435 void DwarfDebug::beginModule() {
436 if (DisableDebugInfoPrinting)
437 return;
438
439 const Module *M = MMI->getModule();
440
441 FunctionDIs = makeSubprogramMap(*M);
442
443 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
444 if (!CU_Nodes)
445 return;
446 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
447
448 // Emit initial sections so we can reference labels later.
449 emitSectionLabels();
450
451 SingleCU = CU_Nodes->getNumOperands() == 1;
452
453 for (MDNode *N : CU_Nodes->operands()) {
454 DICompileUnit CUNode(N);
455 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
456 DIArray ImportedEntities = CUNode.getImportedEntities();
457 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
458 ScopesWithImportedEntities.push_back(std::make_pair(
459 DIImportedEntity(ImportedEntities.getElement(i)).getContext(),
460 ImportedEntities.getElement(i)));
461 std::sort(ScopesWithImportedEntities.begin(),
462 ScopesWithImportedEntities.end(), less_first());
463 DIArray GVs = CUNode.getGlobalVariables();
464 for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
465 CU.getOrCreateGlobalVariableDIE(DIGlobalVariable(GVs.getElement(i)));
466 DIArray SPs = CUNode.getSubprograms();
467 for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
468 SPMap.insert(std::make_pair(SPs.getElement(i), &CU));
469 DIArray EnumTypes = CUNode.getEnumTypes();
470 for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i) {
471 DIType Ty(EnumTypes.getElement(i));
472 // The enum types array by design contains pointers to
473 // MDNodes rather than DIRefs. Unique them here.
474 DIType UniqueTy(resolve(Ty.getRef()));
475 CU.getOrCreateTypeDIE(UniqueTy);
476 }
477 DIArray RetainedTypes = CUNode.getRetainedTypes();
478 for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i) {
479 DIType Ty(RetainedTypes.getElement(i));
480 // The retained types array by design contains pointers to
481 // MDNodes rather than DIRefs. Unique them here.
482 DIType UniqueTy(resolve(Ty.getRef()));
483 CU.getOrCreateTypeDIE(UniqueTy);
484 }
485 // Emit imported_modules last so that the relevant context is already
486 // available.
487 for (unsigned i = 0, e = ImportedEntities.getNumElements(); i != e; ++i)
488 constructAndAddImportedEntityDIE(CU, ImportedEntities.getElement(i));
489 }
490
491 // Tell MMI that we have debug info.
492 MMI->setDebugInfoAvailability(true);
493
494 // Prime section data.
495 SectionMap[Asm->getObjFileLowering().getTextSection()];
496 }
497
finishVariableDefinitions()498 void DwarfDebug::finishVariableDefinitions() {
499 for (const auto &Var : ConcreteVariables) {
500 DIE *VariableDie = Var->getDIE();
501 assert(VariableDie);
502 // FIXME: Consider the time-space tradeoff of just storing the unit pointer
503 // in the ConcreteVariables list, rather than looking it up again here.
504 // DIE::getUnit isn't simple - it walks parent pointers, etc.
505 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit());
506 assert(Unit);
507 DbgVariable *AbsVar = getExistingAbstractVariable(Var->getVariable());
508 if (AbsVar && AbsVar->getDIE()) {
509 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
510 *AbsVar->getDIE());
511 } else
512 Unit->applyVariableAttributes(*Var, *VariableDie);
513 }
514 }
515
finishSubprogramDefinitions()516 void DwarfDebug::finishSubprogramDefinitions() {
517 for (const auto &P : SPMap)
518 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
519 CU.finishSubprogramDefinition(DISubprogram(P.first));
520 });
521 }
522
523
524 // Collect info for variables that were optimized out.
collectDeadVariables()525 void DwarfDebug::collectDeadVariables() {
526 const Module *M = MMI->getModule();
527
528 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
529 for (MDNode *N : CU_Nodes->operands()) {
530 DICompileUnit TheCU(N);
531 // Construct subprogram DIE and add variables DIEs.
532 DwarfCompileUnit *SPCU =
533 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
534 assert(SPCU && "Unable to find Compile Unit!");
535 DIArray Subprograms = TheCU.getSubprograms();
536 for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
537 DISubprogram SP(Subprograms.getElement(i));
538 if (ProcessedSPNodes.count(SP) != 0)
539 continue;
540 SPCU->collectDeadVariables(SP);
541 }
542 }
543 }
544 }
545
finalizeModuleInfo()546 void DwarfDebug::finalizeModuleInfo() {
547 finishSubprogramDefinitions();
548
549 finishVariableDefinitions();
550
551 // Collect info for variables that were optimized out.
552 collectDeadVariables();
553
554 // Handle anything that needs to be done on a per-unit basis after
555 // all other generation.
556 for (const auto &P : CUMap) {
557 auto &TheCU = *P.second;
558 // Emit DW_AT_containing_type attribute to connect types with their
559 // vtable holding type.
560 TheCU.constructContainingTypeDIEs();
561
562 // Add CU specific attributes if we need to add any.
563 // If we're splitting the dwarf out now that we've got the entire
564 // CU then add the dwo id to it.
565 auto *SkCU = TheCU.getSkeleton();
566 if (useSplitDwarf()) {
567 // Emit a unique identifier for this CU.
568 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
569 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
570 dwarf::DW_FORM_data8, ID);
571 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
572 dwarf::DW_FORM_data8, ID);
573
574 // We don't keep track of which addresses are used in which CU so this
575 // is a bit pessimistic under LTO.
576 if (!AddrPool.isEmpty())
577 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base,
578 DwarfAddrSectionSym, DwarfAddrSectionSym);
579 if (!SkCU->getRangeLists().empty())
580 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
581 DwarfDebugRangeSectionSym,
582 DwarfDebugRangeSectionSym);
583 }
584
585 // If we have code split among multiple sections or non-contiguous
586 // ranges of code then emit a DW_AT_ranges attribute on the unit that will
587 // remain in the .o file, otherwise add a DW_AT_low_pc.
588 // FIXME: We should use ranges allow reordering of code ala
589 // .subsections_via_symbols in mach-o. This would mean turning on
590 // ranges for all subprogram DIEs for mach-o.
591 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
592 if (unsigned NumRanges = TheCU.getRanges().size()) {
593 if (NumRanges > 1)
594 // A DW_AT_low_pc attribute may also be specified in combination with
595 // DW_AT_ranges to specify the default base address for use in
596 // location lists (see Section 2.6.2) and range lists (see Section
597 // 2.17.3).
598 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
599 else
600 TheCU.setBaseAddress(TheCU.getRanges().front().getStart());
601 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
602 }
603 }
604
605 // Compute DIE offsets and sizes.
606 InfoHolder.computeSizeAndOffsets();
607 if (useSplitDwarf())
608 SkeletonHolder.computeSizeAndOffsets();
609 }
610
endSections()611 void DwarfDebug::endSections() {
612 // Filter labels by section.
613 for (const SymbolCU &SCU : ArangeLabels) {
614 if (SCU.Sym->isInSection()) {
615 // Make a note of this symbol and it's section.
616 const MCSection *Section = &SCU.Sym->getSection();
617 if (!Section->getKind().isMetadata())
618 SectionMap[Section].push_back(SCU);
619 } else {
620 // Some symbols (e.g. common/bss on mach-o) can have no section but still
621 // appear in the output. This sucks as we rely on sections to build
622 // arange spans. We can do it without, but it's icky.
623 SectionMap[nullptr].push_back(SCU);
624 }
625 }
626
627 // Build a list of sections used.
628 std::vector<const MCSection *> Sections;
629 for (const auto &it : SectionMap) {
630 const MCSection *Section = it.first;
631 Sections.push_back(Section);
632 }
633
634 // Sort the sections into order.
635 // This is only done to ensure consistent output order across different runs.
636 std::sort(Sections.begin(), Sections.end(), SectionSort);
637
638 // Add terminating symbols for each section.
639 for (unsigned ID = 0, E = Sections.size(); ID != E; ID++) {
640 const MCSection *Section = Sections[ID];
641 MCSymbol *Sym = nullptr;
642
643 if (Section) {
644 // We can't call MCSection::getLabelEndName, as it's only safe to do so
645 // if we know the section name up-front. For user-created sections, the
646 // resulting label may not be valid to use as a label. (section names can
647 // use a greater set of characters on some systems)
648 Sym = Asm->GetTempSymbol("debug_end", ID);
649 Asm->OutStreamer.SwitchSection(Section);
650 Asm->OutStreamer.EmitLabel(Sym);
651 }
652
653 // Insert a final terminator.
654 SectionMap[Section].push_back(SymbolCU(nullptr, Sym));
655 }
656 }
657
658 // Emit all Dwarf sections that should come after the content.
endModule()659 void DwarfDebug::endModule() {
660 assert(CurFn == nullptr);
661 assert(CurMI == nullptr);
662
663 // If we aren't actually generating debug info (check beginModule -
664 // conditionalized on !DisableDebugInfoPrinting and the presence of the
665 // llvm.dbg.cu metadata node)
666 if (!DwarfInfoSectionSym)
667 return;
668
669 // End any existing sections.
670 // TODO: Does this need to happen?
671 endSections();
672
673 // Finalize the debug info for the module.
674 finalizeModuleInfo();
675
676 emitDebugStr();
677
678 // Emit all the DIEs into a debug info section.
679 emitDebugInfo();
680
681 // Corresponding abbreviations into a abbrev section.
682 emitAbbreviations();
683
684 // Emit info into a debug aranges section.
685 if (GenerateARangeSection)
686 emitDebugARanges();
687
688 // Emit info into a debug ranges section.
689 emitDebugRanges();
690
691 if (useSplitDwarf()) {
692 emitDebugStrDWO();
693 emitDebugInfoDWO();
694 emitDebugAbbrevDWO();
695 emitDebugLineDWO();
696 emitDebugLocDWO();
697 // Emit DWO addresses.
698 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection());
699 } else
700 // Emit info into a debug loc section.
701 emitDebugLoc();
702
703 // Emit info into the dwarf accelerator table sections.
704 if (useDwarfAccelTables()) {
705 emitAccelNames();
706 emitAccelObjC();
707 emitAccelNamespaces();
708 emitAccelTypes();
709 }
710
711 // Emit the pubnames and pubtypes sections if requested.
712 if (HasDwarfPubSections) {
713 emitDebugPubNames(GenerateGnuPubSections);
714 emitDebugPubTypes(GenerateGnuPubSections);
715 }
716
717 // clean up.
718 SPMap.clear();
719 AbstractVariables.clear();
720 }
721
722 // Find abstract variable, if any, associated with Var.
getExistingAbstractVariable(const DIVariable & DV,DIVariable & Cleansed)723 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV,
724 DIVariable &Cleansed) {
725 LLVMContext &Ctx = DV->getContext();
726 // More then one inlined variable corresponds to one abstract variable.
727 // FIXME: This duplication of variables when inlining should probably be
728 // removed. It's done to allow each DIVariable to describe its location
729 // because the DebugLoc on the dbg.value/declare isn't accurate. We should
730 // make it accurate then remove this duplication/cleansing stuff.
731 Cleansed = cleanseInlinedVariable(DV, Ctx);
732 auto I = AbstractVariables.find(Cleansed);
733 if (I != AbstractVariables.end())
734 return I->second.get();
735 return nullptr;
736 }
737
getExistingAbstractVariable(const DIVariable & DV)738 DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
739 DIVariable Cleansed;
740 return getExistingAbstractVariable(DV, Cleansed);
741 }
742
createAbstractVariable(const DIVariable & Var,LexicalScope * Scope)743 void DwarfDebug::createAbstractVariable(const DIVariable &Var,
744 LexicalScope *Scope) {
745 auto AbsDbgVariable = make_unique<DbgVariable>(Var, DIExpression(), this);
746 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get());
747 AbstractVariables[Var] = std::move(AbsDbgVariable);
748 }
749
ensureAbstractVariableIsCreated(const DIVariable & DV,const MDNode * ScopeNode)750 void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
751 const MDNode *ScopeNode) {
752 DIVariable Cleansed = DV;
753 if (getExistingAbstractVariable(DV, Cleansed))
754 return;
755
756 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
757 }
758
759 void
ensureAbstractVariableIsCreatedIfScoped(const DIVariable & DV,const MDNode * ScopeNode)760 DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
761 const MDNode *ScopeNode) {
762 DIVariable Cleansed = DV;
763 if (getExistingAbstractVariable(DV, Cleansed))
764 return;
765
766 if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
767 createAbstractVariable(Cleansed, Scope);
768 }
769
770 // Collect variable information from side table maintained by MMI.
collectVariableInfoFromMMITable(SmallPtrSetImpl<const MDNode * > & Processed)771 void DwarfDebug::collectVariableInfoFromMMITable(
772 SmallPtrSetImpl<const MDNode *> &Processed) {
773 for (const auto &VI : MMI->getVariableDbgInfo()) {
774 if (!VI.Var)
775 continue;
776 Processed.insert(VI.Var);
777 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
778
779 // If variable scope is not found then skip this variable.
780 if (!Scope)
781 continue;
782
783 DIVariable DV(VI.Var);
784 DIExpression Expr(VI.Expr);
785 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
786 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
787 DbgVariable *RegVar = ConcreteVariables.back().get();
788 RegVar->setFrameIndex(VI.Slot);
789 InfoHolder.addScopeVariable(Scope, RegVar);
790 }
791 }
792
793 // Get .debug_loc entry for the instruction range starting at MI.
getDebugLocValue(const MachineInstr * MI)794 static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
795 const MDNode *Expr = MI->getDebugExpression();
796 const MDNode *Var = MI->getDebugVariable();
797
798 assert(MI->getNumOperands() == 4);
799 if (MI->getOperand(0).isReg()) {
800 MachineLocation MLoc;
801 // If the second operand is an immediate, this is a
802 // register-indirect address.
803 if (!MI->getOperand(1).isImm())
804 MLoc.set(MI->getOperand(0).getReg());
805 else
806 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
807 return DebugLocEntry::Value(Var, Expr, MLoc);
808 }
809 if (MI->getOperand(0).isImm())
810 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getImm());
811 if (MI->getOperand(0).isFPImm())
812 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getFPImm());
813 if (MI->getOperand(0).isCImm())
814 return DebugLocEntry::Value(Var, Expr, MI->getOperand(0).getCImm());
815
816 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!");
817 }
818
819 /// Determine whether two variable pieces overlap.
piecesOverlap(DIExpression P1,DIExpression P2)820 static bool piecesOverlap(DIExpression P1, DIExpression P2) {
821 if (!P1.isVariablePiece() || !P2.isVariablePiece())
822 return true;
823 unsigned l1 = P1.getPieceOffset();
824 unsigned l2 = P2.getPieceOffset();
825 unsigned r1 = l1 + P1.getPieceSize();
826 unsigned r2 = l2 + P2.getPieceSize();
827 // True where [l1,r1[ and [r1,r2[ overlap.
828 return (l1 < r2) && (l2 < r1);
829 }
830
831 /// Build the location list for all DBG_VALUEs in the function that
832 /// describe the same variable. If the ranges of several independent
833 /// pieces of the same variable overlap partially, split them up and
834 /// combine the ranges. The resulting DebugLocEntries are will have
835 /// strict monotonically increasing begin addresses and will never
836 /// overlap.
837 //
838 // Input:
839 //
840 // Ranges History [var, loc, piece ofs size]
841 // 0 | [x, (reg0, piece 0, 32)]
842 // 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
843 // 2 | | ...
844 // 3 | [clobber reg0]
845 // 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
846 //
847 // Output:
848 //
849 // [0-1] [x, (reg0, piece 0, 32)]
850 // [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
851 // [3-4] [x, (reg1, piece 32, 32)]
852 // [4- ] [x, (mem, piece 0, 64)]
853 void
buildLocationList(SmallVectorImpl<DebugLocEntry> & DebugLoc,const DbgValueHistoryMap::InstrRanges & Ranges)854 DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
855 const DbgValueHistoryMap::InstrRanges &Ranges) {
856 SmallVector<DebugLocEntry::Value, 4> OpenRanges;
857
858 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
859 const MachineInstr *Begin = I->first;
860 const MachineInstr *End = I->second;
861 assert(Begin->isDebugValue() && "Invalid History entry");
862
863 // Check if a variable is inaccessible in this range.
864 if (Begin->getNumOperands() > 1 &&
865 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) {
866 OpenRanges.clear();
867 continue;
868 }
869
870 // If this piece overlaps with any open ranges, truncate them.
871 DIExpression DIExpr = Begin->getDebugExpression();
872 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(),
873 [&](DebugLocEntry::Value R) {
874 return piecesOverlap(DIExpr, R.getExpression());
875 });
876 OpenRanges.erase(Last, OpenRanges.end());
877
878 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
879 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
880
881 const MCSymbol *EndLabel;
882 if (End != nullptr)
883 EndLabel = getLabelAfterInsn(End);
884 else if (std::next(I) == Ranges.end())
885 EndLabel = FunctionEndSym;
886 else
887 EndLabel = getLabelBeforeInsn(std::next(I)->first);
888 assert(EndLabel && "Forgot label after instruction ending a range!");
889
890 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
891
892 auto Value = getDebugLocValue(Begin);
893 DebugLocEntry Loc(StartLabel, EndLabel, Value);
894 bool couldMerge = false;
895
896 // If this is a piece, it may belong to the current DebugLocEntry.
897 if (DIExpr.isVariablePiece()) {
898 // Add this value to the list of open ranges.
899 OpenRanges.push_back(Value);
900
901 // Attempt to add the piece to the last entry.
902 if (!DebugLoc.empty())
903 if (DebugLoc.back().MergeValues(Loc))
904 couldMerge = true;
905 }
906
907 if (!couldMerge) {
908 // Need to add a new DebugLocEntry. Add all values from still
909 // valid non-overlapping pieces.
910 if (OpenRanges.size())
911 Loc.addValues(OpenRanges);
912
913 DebugLoc.push_back(std::move(Loc));
914 }
915
916 // Attempt to coalesce the ranges of two otherwise identical
917 // DebugLocEntries.
918 auto CurEntry = DebugLoc.rbegin();
919 auto PrevEntry = std::next(CurEntry);
920 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry))
921 DebugLoc.pop_back();
922
923 DEBUG({
924 dbgs() << CurEntry->getValues().size() << " Values:\n";
925 for (auto Value : CurEntry->getValues()) {
926 Value.getVariable()->dump();
927 Value.getExpression()->dump();
928 }
929 dbgs() << "-----\n";
930 });
931 }
932 }
933
934
935 // Find variables for each lexical scope.
936 void
collectVariableInfo(DwarfCompileUnit & TheCU,DISubprogram SP,SmallPtrSetImpl<const MDNode * > & Processed)937 DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
938 SmallPtrSetImpl<const MDNode *> &Processed) {
939 // Grab the variable info that was squirreled away in the MMI side-table.
940 collectVariableInfoFromMMITable(Processed);
941
942 for (const auto &I : DbgValues) {
943 DIVariable DV(I.first);
944 if (Processed.count(DV))
945 continue;
946
947 // Instruction ranges, specifying where DV is accessible.
948 const auto &Ranges = I.second;
949 if (Ranges.empty())
950 continue;
951
952 LexicalScope *Scope = nullptr;
953 if (MDNode *IA = DV.getInlinedAt()) {
954 DebugLoc DL = DebugLoc::getFromDILocation(IA);
955 Scope = LScopes.findInlinedScope(DebugLoc::get(
956 DL.getLine(), DL.getCol(), DV.getContext(), IA));
957 } else
958 Scope = LScopes.findLexicalScope(DV.getContext());
959 // If variable scope is not found then skip this variable.
960 if (!Scope)
961 continue;
962
963 Processed.insert(DV);
964 const MachineInstr *MInsn = Ranges.front().first;
965 assert(MInsn->isDebugValue() && "History must begin with debug value");
966 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
967 ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
968 DbgVariable *RegVar = ConcreteVariables.back().get();
969 InfoHolder.addScopeVariable(Scope, RegVar);
970
971 // Check if the first DBG_VALUE is valid for the rest of the function.
972 if (Ranges.size() == 1 && Ranges.front().second == nullptr)
973 continue;
974
975 // Handle multiple DBG_VALUE instructions describing one variable.
976 RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
977
978 DotDebugLocEntries.resize(DotDebugLocEntries.size() + 1);
979 DebugLocList &LocList = DotDebugLocEntries.back();
980 LocList.CU = &TheCU;
981 LocList.Label =
982 Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
983
984 // Build the location list for this variable.
985 buildLocationList(LocList.List, Ranges);
986 }
987
988 // Collect info for variables that were optimized out.
989 DIArray Variables = SP.getVariables();
990 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
991 DIVariable DV(Variables.getElement(i));
992 assert(DV.isVariable());
993 if (!Processed.insert(DV).second)
994 continue;
995 if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
996 ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
997 DIExpression NoExpr;
998 ConcreteVariables.push_back(make_unique<DbgVariable>(DV, NoExpr, this));
999 InfoHolder.addScopeVariable(Scope, ConcreteVariables.back().get());
1000 }
1001 }
1002 }
1003
1004 // Return Label preceding the instruction.
getLabelBeforeInsn(const MachineInstr * MI)1005 MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
1006 MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
1007 assert(Label && "Didn't insert label before instruction");
1008 return Label;
1009 }
1010
1011 // Return Label immediately following the instruction.
getLabelAfterInsn(const MachineInstr * MI)1012 MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
1013 return LabelsAfterInsn.lookup(MI);
1014 }
1015
1016 // Process beginning of an instruction.
beginInstruction(const MachineInstr * MI)1017 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
1018 assert(CurMI == nullptr);
1019 CurMI = MI;
1020 // Check if source location changes, but ignore DBG_VALUE locations.
1021 if (!MI->isDebugValue()) {
1022 DebugLoc DL = MI->getDebugLoc();
1023 if (DL != PrevInstLoc && (!DL.isUnknown() || UnknownLocations)) {
1024 unsigned Flags = 0;
1025 PrevInstLoc = DL;
1026 if (DL == PrologEndLoc) {
1027 Flags |= DWARF2_FLAG_PROLOGUE_END;
1028 PrologEndLoc = DebugLoc();
1029 Flags |= DWARF2_FLAG_IS_STMT;
1030 }
1031 if (DL.getLine() !=
1032 Asm->OutStreamer.getContext().getCurrentDwarfLoc().getLine())
1033 Flags |= DWARF2_FLAG_IS_STMT;
1034
1035 if (!DL.isUnknown()) {
1036 const MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
1037 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags);
1038 } else
1039 recordSourceLine(0, 0, nullptr, 0);
1040 }
1041 }
1042
1043 // Insert labels where requested.
1044 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1045 LabelsBeforeInsn.find(MI);
1046
1047 // No label needed.
1048 if (I == LabelsBeforeInsn.end())
1049 return;
1050
1051 // Label already assigned.
1052 if (I->second)
1053 return;
1054
1055 if (!PrevLabel) {
1056 PrevLabel = MMI->getContext().CreateTempSymbol();
1057 Asm->OutStreamer.EmitLabel(PrevLabel);
1058 }
1059 I->second = PrevLabel;
1060 }
1061
1062 // Process end of an instruction.
endInstruction()1063 void DwarfDebug::endInstruction() {
1064 assert(CurMI != nullptr);
1065 // Don't create a new label after DBG_VALUE instructions.
1066 // They don't generate code.
1067 if (!CurMI->isDebugValue())
1068 PrevLabel = nullptr;
1069
1070 DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
1071 LabelsAfterInsn.find(CurMI);
1072 CurMI = nullptr;
1073
1074 // No label needed.
1075 if (I == LabelsAfterInsn.end())
1076 return;
1077
1078 // Label already assigned.
1079 if (I->second)
1080 return;
1081
1082 // We need a label after this instruction.
1083 if (!PrevLabel) {
1084 PrevLabel = MMI->getContext().CreateTempSymbol();
1085 Asm->OutStreamer.EmitLabel(PrevLabel);
1086 }
1087 I->second = PrevLabel;
1088 }
1089
1090 // Each LexicalScope has first instruction and last instruction to mark
1091 // beginning and end of a scope respectively. Create an inverse map that list
1092 // scopes starts (and ends) with an instruction. One instruction may start (or
1093 // end) multiple scopes. Ignore scopes that are not reachable.
identifyScopeMarkers()1094 void DwarfDebug::identifyScopeMarkers() {
1095 SmallVector<LexicalScope *, 4> WorkList;
1096 WorkList.push_back(LScopes.getCurrentFunctionScope());
1097 while (!WorkList.empty()) {
1098 LexicalScope *S = WorkList.pop_back_val();
1099
1100 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
1101 if (!Children.empty())
1102 WorkList.append(Children.begin(), Children.end());
1103
1104 if (S->isAbstractScope())
1105 continue;
1106
1107 for (const InsnRange &R : S->getRanges()) {
1108 assert(R.first && "InsnRange does not have first instruction!");
1109 assert(R.second && "InsnRange does not have second instruction!");
1110 requestLabelBeforeInsn(R.first);
1111 requestLabelAfterInsn(R.second);
1112 }
1113 }
1114 }
1115
findPrologueEndLoc(const MachineFunction * MF)1116 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
1117 // First known non-DBG_VALUE and non-frame setup location marks
1118 // the beginning of the function body.
1119 for (const auto &MBB : *MF)
1120 for (const auto &MI : MBB)
1121 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
1122 !MI.getDebugLoc().isUnknown()) {
1123 // Did the target forget to set the FrameSetup flag for CFI insns?
1124 assert(!MI.isCFIInstruction() &&
1125 "First non-frame-setup instruction is a CFI instruction.");
1126 return MI.getDebugLoc();
1127 }
1128 return DebugLoc();
1129 }
1130
1131 // Gather pre-function debug information. Assumes being called immediately
1132 // after the function entry point has been emitted.
beginFunction(const MachineFunction * MF)1133 void DwarfDebug::beginFunction(const MachineFunction *MF) {
1134 CurFn = MF;
1135
1136 // If there's no debug info for the function we're not going to do anything.
1137 if (!MMI->hasDebugInfo())
1138 return;
1139
1140 auto DI = FunctionDIs.find(MF->getFunction());
1141 if (DI == FunctionDIs.end())
1142 return;
1143
1144 // Grab the lexical scopes for the function, if we don't have any of those
1145 // then we're not going to be able to do anything.
1146 LScopes.initialize(*MF);
1147 if (LScopes.empty())
1148 return;
1149
1150 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
1151
1152 // Make sure that each lexical scope will have a begin/end label.
1153 identifyScopeMarkers();
1154
1155 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
1156 // belongs to so that we add to the correct per-cu line table in the
1157 // non-asm case.
1158 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1159 // FnScope->getScopeNode() and DI->second should represent the same function,
1160 // though they may not be the same MDNode due to inline functions merged in
1161 // LTO where the debug info metadata still differs (either due to distinct
1162 // written differences - two versions of a linkonce_odr function
1163 // written/copied into two separate files, or some sub-optimal metadata that
1164 // isn't structurally identical (see: file path/name info from clang, which
1165 // includes the directory of the cpp file being built, even when the file name
1166 // is absolute (such as an <> lookup header)))
1167 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
1168 assert(TheCU && "Unable to find compile unit!");
1169 if (Asm->OutStreamer.hasRawTextSupport())
1170 // Use a single line table if we are generating assembly.
1171 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1172 else
1173 Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
1174
1175 // Emit a label for the function so that we have a beginning address.
1176 FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber());
1177 // Assumes in correct section after the entry point.
1178 Asm->OutStreamer.EmitLabel(FunctionBeginSym);
1179
1180 // Calculate history for local variables.
1181 calculateDbgValueHistory(MF, Asm->TM.getSubtargetImpl()->getRegisterInfo(),
1182 DbgValues);
1183
1184 // Request labels for the full history.
1185 for (const auto &I : DbgValues) {
1186 const auto &Ranges = I.second;
1187 if (Ranges.empty())
1188 continue;
1189
1190 // The first mention of a function argument gets the FunctionBeginSym
1191 // label, so arguments are visible when breaking at function entry.
1192 DIVariable DIVar(Ranges.front().first->getDebugVariable());
1193 if (DIVar.isVariable() && DIVar.getTag() == dwarf::DW_TAG_arg_variable &&
1194 getDISubprogram(DIVar.getContext()).describes(MF->getFunction())) {
1195 LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
1196 if (Ranges.front().first->getDebugExpression().isVariablePiece()) {
1197 // Mark all non-overlapping initial pieces.
1198 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
1199 DIExpression Piece = I->first->getDebugExpression();
1200 if (std::all_of(Ranges.begin(), I,
1201 [&](DbgValueHistoryMap::InstrRange Pred) {
1202 return !piecesOverlap(Piece, Pred.first->getDebugExpression());
1203 }))
1204 LabelsBeforeInsn[I->first] = FunctionBeginSym;
1205 else
1206 break;
1207 }
1208 }
1209 }
1210
1211 for (const auto &Range : Ranges) {
1212 requestLabelBeforeInsn(Range.first);
1213 if (Range.second)
1214 requestLabelAfterInsn(Range.second);
1215 }
1216 }
1217
1218 PrevInstLoc = DebugLoc();
1219 PrevLabel = FunctionBeginSym;
1220
1221 // Record beginning of function.
1222 PrologEndLoc = findPrologueEndLoc(MF);
1223 if (!PrologEndLoc.isUnknown()) {
1224 DebugLoc FnStartDL =
1225 PrologEndLoc.getFnDebugLoc(MF->getFunction()->getContext());
1226 recordSourceLine(
1227 FnStartDL.getLine(), FnStartDL.getCol(),
1228 FnStartDL.getScope(MF->getFunction()->getContext()),
1229 // We'd like to list the prologue as "not statements" but GDB behaves
1230 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
1231 DWARF2_FLAG_IS_STMT);
1232 }
1233 }
1234
1235 // Gather and emit post-function debug information.
endFunction(const MachineFunction * MF)1236 void DwarfDebug::endFunction(const MachineFunction *MF) {
1237 assert(CurFn == MF &&
1238 "endFunction should be called with the same function as beginFunction");
1239
1240 if (!MMI->hasDebugInfo() || LScopes.empty() ||
1241 !FunctionDIs.count(MF->getFunction())) {
1242 // If we don't have a lexical scope for this function then there will
1243 // be a hole in the range information. Keep note of this by setting the
1244 // previously used section to nullptr.
1245 PrevCU = nullptr;
1246 CurFn = nullptr;
1247 return;
1248 }
1249
1250 // Define end label for subprogram.
1251 FunctionEndSym = Asm->GetTempSymbol("func_end", Asm->getFunctionNumber());
1252 // Assumes in correct section after the entry point.
1253 Asm->OutStreamer.EmitLabel(FunctionEndSym);
1254
1255 // Set DwarfDwarfCompileUnitID in MCContext to default value.
1256 Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
1257
1258 LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
1259 DISubprogram SP(FnScope->getScopeNode());
1260 DwarfCompileUnit &TheCU = *SPMap.lookup(SP);
1261
1262 SmallPtrSet<const MDNode *, 16> ProcessedVars;
1263 collectVariableInfo(TheCU, SP, ProcessedVars);
1264
1265 // Add the range of this function to the list of ranges for the CU.
1266 TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
1267
1268 // Under -gmlt, skip building the subprogram if there are no inlined
1269 // subroutines inside it.
1270 if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
1271 LScopes.getAbstractScopesList().empty() && !IsDarwin) {
1272 assert(InfoHolder.getScopeVariables().empty());
1273 assert(DbgValues.empty());
1274 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed
1275 // by a -gmlt CU. Add a test and remove this assertion.
1276 assert(AbstractVariables.empty());
1277 LabelsBeforeInsn.clear();
1278 LabelsAfterInsn.clear();
1279 PrevLabel = nullptr;
1280 CurFn = nullptr;
1281 return;
1282 }
1283
1284 #ifndef NDEBUG
1285 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
1286 #endif
1287 // Construct abstract scopes.
1288 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
1289 DISubprogram SP(AScope->getScopeNode());
1290 assert(SP.isSubprogram());
1291 // Collect info for variables that were optimized out.
1292 DIArray Variables = SP.getVariables();
1293 for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
1294 DIVariable DV(Variables.getElement(i));
1295 assert(DV && DV.isVariable());
1296 if (!ProcessedVars.insert(DV).second)
1297 continue;
1298 ensureAbstractVariableIsCreated(DV, DV.getContext());
1299 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
1300 && "ensureAbstractVariableIsCreated inserted abstract scopes");
1301 }
1302 constructAbstractSubprogramScopeDIE(AScope);
1303 }
1304
1305 TheCU.constructSubprogramScopeDIE(FnScope);
1306 if (auto *SkelCU = TheCU.getSkeleton())
1307 if (!LScopes.getAbstractScopesList().empty())
1308 SkelCU->constructSubprogramScopeDIE(FnScope);
1309
1310 // Clear debug info
1311 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
1312 // DbgVariables except those that are also in AbstractVariables (since they
1313 // can be used cross-function)
1314 InfoHolder.getScopeVariables().clear();
1315 DbgValues.clear();
1316 LabelsBeforeInsn.clear();
1317 LabelsAfterInsn.clear();
1318 PrevLabel = nullptr;
1319 CurFn = nullptr;
1320 }
1321
1322 // Register a source line with debug info. Returns the unique label that was
1323 // emitted and which provides correspondence to the source line list.
recordSourceLine(unsigned Line,unsigned Col,const MDNode * S,unsigned Flags)1324 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
1325 unsigned Flags) {
1326 StringRef Fn;
1327 StringRef Dir;
1328 unsigned Src = 1;
1329 unsigned Discriminator = 0;
1330 if (DIScope Scope = DIScope(S)) {
1331 assert(Scope.isScope());
1332 Fn = Scope.getFilename();
1333 Dir = Scope.getDirectory();
1334 if (Scope.isLexicalBlockFile())
1335 Discriminator = DILexicalBlockFile(S).getDiscriminator();
1336
1337 unsigned CUID = Asm->OutStreamer.getContext().getDwarfCompileUnitID();
1338 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
1339 .getOrCreateSourceID(Fn, Dir);
1340 }
1341 Asm->OutStreamer.EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
1342 Discriminator, Fn);
1343 }
1344
1345 //===----------------------------------------------------------------------===//
1346 // Emit Methods
1347 //===----------------------------------------------------------------------===//
1348
1349 // Emit initial Dwarf sections with a label at the start of each one.
emitSectionLabels()1350 void DwarfDebug::emitSectionLabels() {
1351 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1352
1353 // Dwarf sections base addresses.
1354 DwarfInfoSectionSym =
1355 emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
1356 if (useSplitDwarf()) {
1357 DwarfInfoDWOSectionSym =
1358 emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
1359 DwarfTypesDWOSectionSym =
1360 emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
1361 }
1362 DwarfAbbrevSectionSym =
1363 emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
1364 if (useSplitDwarf())
1365 DwarfAbbrevDWOSectionSym = emitSectionSym(
1366 Asm, TLOF.getDwarfAbbrevDWOSection(), "section_abbrev_dwo");
1367 if (GenerateARangeSection)
1368 emitSectionSym(Asm, TLOF.getDwarfARangesSection());
1369
1370 DwarfLineSectionSym =
1371 emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
1372 if (GenerateGnuPubSections) {
1373 DwarfGnuPubNamesSectionSym =
1374 emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
1375 DwarfGnuPubTypesSectionSym =
1376 emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
1377 } else if (HasDwarfPubSections) {
1378 emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
1379 emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
1380 }
1381
1382 DwarfStrSectionSym =
1383 emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
1384 if (useSplitDwarf()) {
1385 DwarfStrDWOSectionSym =
1386 emitSectionSym(Asm, TLOF.getDwarfStrDWOSection(), "skel_string");
1387 DwarfAddrSectionSym =
1388 emitSectionSym(Asm, TLOF.getDwarfAddrSection(), "addr_sec");
1389 DwarfDebugLocSectionSym =
1390 emitSectionSym(Asm, TLOF.getDwarfLocDWOSection(), "skel_loc");
1391 } else
1392 DwarfDebugLocSectionSym =
1393 emitSectionSym(Asm, TLOF.getDwarfLocSection(), "section_debug_loc");
1394 DwarfDebugRangeSectionSym =
1395 emitSectionSym(Asm, TLOF.getDwarfRangesSection(), "debug_range");
1396 }
1397
1398 // Recursively emits a debug information entry.
emitDIE(DIE & Die)1399 void DwarfDebug::emitDIE(DIE &Die) {
1400 // Get the abbreviation for this DIE.
1401 const DIEAbbrev &Abbrev = Die.getAbbrev();
1402
1403 // Emit the code (index) for the abbreviation.
1404 if (Asm->isVerbose())
1405 Asm->OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
1406 "] 0x" + Twine::utohexstr(Die.getOffset()) +
1407 ":0x" + Twine::utohexstr(Die.getSize()) + " " +
1408 dwarf::TagString(Abbrev.getTag()));
1409 Asm->EmitULEB128(Abbrev.getNumber());
1410
1411 const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
1412 const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
1413
1414 // Emit the DIE attribute values.
1415 for (unsigned i = 0, N = Values.size(); i < N; ++i) {
1416 dwarf::Attribute Attr = AbbrevData[i].getAttribute();
1417 dwarf::Form Form = AbbrevData[i].getForm();
1418 assert(Form && "Too many attributes for DIE (check abbreviation)");
1419
1420 if (Asm->isVerbose()) {
1421 Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr));
1422 if (Attr == dwarf::DW_AT_accessibility)
1423 Asm->OutStreamer.AddComment(dwarf::AccessibilityString(
1424 cast<DIEInteger>(Values[i])->getValue()));
1425 }
1426
1427 // Emit an attribute using the defined form.
1428 Values[i]->EmitValue(Asm, Form);
1429 }
1430
1431 // Emit the DIE children if any.
1432 if (Abbrev.hasChildren()) {
1433 for (auto &Child : Die.getChildren())
1434 emitDIE(*Child);
1435
1436 Asm->OutStreamer.AddComment("End Of Children Mark");
1437 Asm->EmitInt8(0);
1438 }
1439 }
1440
1441 // Emit the debug info section.
emitDebugInfo()1442 void DwarfDebug::emitDebugInfo() {
1443 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1444
1445 Holder.emitUnits(DwarfAbbrevSectionSym);
1446 }
1447
1448 // Emit the abbreviation section.
emitAbbreviations()1449 void DwarfDebug::emitAbbreviations() {
1450 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1451
1452 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
1453 }
1454
1455 // Emit the last address of the section and the end of the line matrix.
emitEndOfLineMatrix(unsigned SectionEnd)1456 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
1457 // Define last address of section.
1458 Asm->OutStreamer.AddComment("Extended Op");
1459 Asm->EmitInt8(0);
1460
1461 Asm->OutStreamer.AddComment("Op size");
1462 Asm->EmitInt8(Asm->getDataLayout().getPointerSize() + 1);
1463 Asm->OutStreamer.AddComment("DW_LNE_set_address");
1464 Asm->EmitInt8(dwarf::DW_LNE_set_address);
1465
1466 Asm->OutStreamer.AddComment("Section end label");
1467
1468 Asm->OutStreamer.EmitSymbolValue(
1469 Asm->GetTempSymbol("section_end", SectionEnd),
1470 Asm->getDataLayout().getPointerSize());
1471
1472 // Mark end of matrix.
1473 Asm->OutStreamer.AddComment("DW_LNE_end_sequence");
1474 Asm->EmitInt8(0);
1475 Asm->EmitInt8(1);
1476 Asm->EmitInt8(1);
1477 }
1478
emitAccel(DwarfAccelTable & Accel,const MCSection * Section,StringRef TableName,StringRef SymName)1479 void DwarfDebug::emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
1480 StringRef TableName, StringRef SymName) {
1481 Accel.FinalizeTable(Asm, TableName);
1482 Asm->OutStreamer.SwitchSection(Section);
1483 auto *SectionBegin = Asm->GetTempSymbol(SymName);
1484 Asm->OutStreamer.EmitLabel(SectionBegin);
1485
1486 // Emit the full data.
1487 Accel.Emit(Asm, SectionBegin, this, DwarfStrSectionSym);
1488 }
1489
1490 // Emit visible names into a hashed accelerator table section.
emitAccelNames()1491 void DwarfDebug::emitAccelNames() {
1492 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(),
1493 "Names", "names_begin");
1494 }
1495
1496 // Emit objective C classes and categories into a hashed accelerator table
1497 // section.
emitAccelObjC()1498 void DwarfDebug::emitAccelObjC() {
1499 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(),
1500 "ObjC", "objc_begin");
1501 }
1502
1503 // Emit namespace dies into a hashed accelerator table.
emitAccelNamespaces()1504 void DwarfDebug::emitAccelNamespaces() {
1505 emitAccel(AccelNamespace,
1506 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(),
1507 "namespac", "namespac_begin");
1508 }
1509
1510 // Emit type dies into a hashed accelerator table.
emitAccelTypes()1511 void DwarfDebug::emitAccelTypes() {
1512 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(),
1513 "types", "types_begin");
1514 }
1515
1516 // Public name handling.
1517 // The format for the various pubnames:
1518 //
1519 // dwarf pubnames - offset/name pairs where the offset is the offset into the CU
1520 // for the DIE that is named.
1521 //
1522 // gnu pubnames - offset/index value/name tuples where the offset is the offset
1523 // into the CU and the index value is computed according to the type of value
1524 // for the DIE that is named.
1525 //
1526 // For type units the offset is the offset of the skeleton DIE. For split dwarf
1527 // it's the offset within the debug_info/debug_types dwo section, however, the
1528 // reference in the pubname header doesn't change.
1529
1530 /// computeIndexValue - Compute the gdb index value for the DIE and CU.
computeIndexValue(DwarfUnit * CU,const DIE * Die)1531 static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
1532 const DIE *Die) {
1533 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC;
1534
1535 // We could have a specification DIE that has our most of our knowledge,
1536 // look for that now.
1537 DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
1538 if (SpecVal) {
1539 DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
1540 if (SpecDIE.findAttribute(dwarf::DW_AT_external))
1541 Linkage = dwarf::GIEL_EXTERNAL;
1542 } else if (Die->findAttribute(dwarf::DW_AT_external))
1543 Linkage = dwarf::GIEL_EXTERNAL;
1544
1545 switch (Die->getTag()) {
1546 case dwarf::DW_TAG_class_type:
1547 case dwarf::DW_TAG_structure_type:
1548 case dwarf::DW_TAG_union_type:
1549 case dwarf::DW_TAG_enumeration_type:
1550 return dwarf::PubIndexEntryDescriptor(
1551 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus
1552 ? dwarf::GIEL_STATIC
1553 : dwarf::GIEL_EXTERNAL);
1554 case dwarf::DW_TAG_typedef:
1555 case dwarf::DW_TAG_base_type:
1556 case dwarf::DW_TAG_subrange_type:
1557 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC);
1558 case dwarf::DW_TAG_namespace:
1559 return dwarf::GIEK_TYPE;
1560 case dwarf::DW_TAG_subprogram:
1561 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage);
1562 case dwarf::DW_TAG_constant:
1563 case dwarf::DW_TAG_variable:
1564 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage);
1565 case dwarf::DW_TAG_enumerator:
1566 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE,
1567 dwarf::GIEL_STATIC);
1568 default:
1569 return dwarf::GIEK_NONE;
1570 }
1571 }
1572
1573 /// emitDebugPubNames - Emit visible names into a debug pubnames section.
1574 ///
emitDebugPubNames(bool GnuStyle)1575 void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
1576 const MCSection *PSec =
1577 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
1578 : Asm->getObjFileLowering().getDwarfPubNamesSection();
1579
1580 emitDebugPubSection(GnuStyle, PSec, "Names",
1581 &DwarfCompileUnit::getGlobalNames);
1582 }
1583
emitDebugPubSection(bool GnuStyle,const MCSection * PSec,StringRef Name,const StringMap<const DIE * > & (DwarfCompileUnit::* Accessor)()const)1584 void DwarfDebug::emitDebugPubSection(
1585 bool GnuStyle, const MCSection *PSec, StringRef Name,
1586 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) {
1587 for (const auto &NU : CUMap) {
1588 DwarfCompileUnit *TheU = NU.second;
1589
1590 const auto &Globals = (TheU->*Accessor)();
1591
1592 if (Globals.empty())
1593 continue;
1594
1595 if (auto *Skeleton = TheU->getSkeleton())
1596 TheU = Skeleton;
1597 unsigned ID = TheU->getUniqueID();
1598
1599 // Start the dwarf pubnames section.
1600 Asm->OutStreamer.SwitchSection(PSec);
1601
1602 // Emit the header.
1603 Asm->OutStreamer.AddComment("Length of Public " + Name + " Info");
1604 MCSymbol *BeginLabel = Asm->GetTempSymbol("pub" + Name + "_begin", ID);
1605 MCSymbol *EndLabel = Asm->GetTempSymbol("pub" + Name + "_end", ID);
1606 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
1607
1608 Asm->OutStreamer.EmitLabel(BeginLabel);
1609
1610 Asm->OutStreamer.AddComment("DWARF Version");
1611 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION);
1612
1613 Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
1614 Asm->EmitSectionOffset(TheU->getLabelBegin(), TheU->getSectionSym());
1615
1616 Asm->OutStreamer.AddComment("Compilation Unit Length");
1617 Asm->EmitInt32(TheU->getLength());
1618
1619 // Emit the pubnames for this compilation unit.
1620 for (const auto &GI : Globals) {
1621 const char *Name = GI.getKeyData();
1622 const DIE *Entity = GI.second;
1623
1624 Asm->OutStreamer.AddComment("DIE offset");
1625 Asm->EmitInt32(Entity->getOffset());
1626
1627 if (GnuStyle) {
1628 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity);
1629 Asm->OutStreamer.AddComment(
1630 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " +
1631 dwarf::GDBIndexEntryLinkageString(Desc.Linkage));
1632 Asm->EmitInt8(Desc.toBits());
1633 }
1634
1635 Asm->OutStreamer.AddComment("External Name");
1636 Asm->OutStreamer.EmitBytes(StringRef(Name, GI.getKeyLength() + 1));
1637 }
1638
1639 Asm->OutStreamer.AddComment("End Mark");
1640 Asm->EmitInt32(0);
1641 Asm->OutStreamer.EmitLabel(EndLabel);
1642 }
1643 }
1644
emitDebugPubTypes(bool GnuStyle)1645 void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
1646 const MCSection *PSec =
1647 GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection()
1648 : Asm->getObjFileLowering().getDwarfPubTypesSection();
1649
1650 emitDebugPubSection(GnuStyle, PSec, "Types",
1651 &DwarfCompileUnit::getGlobalTypes);
1652 }
1653
1654 // Emit visible names into a debug str section.
emitDebugStr()1655 void DwarfDebug::emitDebugStr() {
1656 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
1657 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
1658 }
1659
1660 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
emitLocPieces(ByteStreamer & Streamer,const DITypeIdentifierMap & Map,ArrayRef<DebugLocEntry::Value> Values)1661 void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
1662 const DITypeIdentifierMap &Map,
1663 ArrayRef<DebugLocEntry::Value> Values) {
1664 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) {
1665 return P.isVariablePiece();
1666 }) && "all values are expected to be pieces");
1667 assert(std::is_sorted(Values.begin(), Values.end()) &&
1668 "pieces are expected to be sorted");
1669
1670 unsigned Offset = 0;
1671 for (auto Piece : Values) {
1672 const unsigned SizeOfByte = 8;
1673 DIExpression Expr = Piece.getExpression();
1674 unsigned PieceOffset = Expr.getPieceOffset();
1675 unsigned PieceSize = Expr.getPieceSize();
1676 assert(Offset <= PieceOffset && "overlapping or duplicate pieces");
1677 if (Offset < PieceOffset) {
1678 // The DWARF spec seriously mandates pieces with no locations for gaps.
1679 Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*SizeOfByte);
1680 Offset += PieceOffset-Offset;
1681 }
1682 Offset += PieceSize;
1683
1684 #ifndef NDEBUG
1685 DIVariable Var = Piece.getVariable();
1686 assert(!Var.isIndirect() && "indirect address for piece");
1687 unsigned VarSize = Var.getSizeInBits(Map);
1688 assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
1689 && "piece is larger than or outside of variable");
1690 assert(PieceSize*SizeOfByte != VarSize
1691 && "piece covers entire variable");
1692 #endif
1693
1694 emitDebugLocValue(Streamer, Piece, PieceOffset*SizeOfByte);
1695 }
1696 }
1697
1698
emitDebugLocEntry(ByteStreamer & Streamer,const DebugLocEntry & Entry)1699 void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
1700 const DebugLocEntry &Entry) {
1701 const DebugLocEntry::Value Value = Entry.getValues()[0];
1702 if (Value.isVariablePiece())
1703 // Emit all pieces that belong to the same variable and range.
1704 return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
1705
1706 assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
1707 emitDebugLocValue(Streamer, Value);
1708 }
1709
emitDebugLocValue(ByteStreamer & Streamer,const DebugLocEntry::Value & Value,unsigned PieceOffsetInBits)1710 void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
1711 const DebugLocEntry::Value &Value,
1712 unsigned PieceOffsetInBits) {
1713 DIVariable DV = Value.getVariable();
1714 DebugLocDwarfExpression DwarfExpr(*Asm, Streamer);
1715
1716 // Regular entry.
1717 if (Value.isInt()) {
1718 DIBasicType BTy(resolve(DV.getType()));
1719 if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
1720 BTy.getEncoding() == dwarf::DW_ATE_signed_char))
1721 DwarfExpr.AddSignedConstant(Value.getInt());
1722 else
1723 DwarfExpr.AddUnsignedConstant(Value.getInt());
1724 } else if (Value.isLocation()) {
1725 MachineLocation Loc = Value.getLoc();
1726 DIExpression Expr = Value.getExpression();
1727 if (!Expr || (Expr.getNumElements() == 0))
1728 // Regular entry.
1729 Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
1730 else {
1731 // Complex address entry.
1732 if (Loc.getOffset()) {
1733 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
1734 DwarfExpr.AddExpression(Expr, PieceOffsetInBits);
1735 } else
1736 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
1737 PieceOffsetInBits);
1738 if (DV.isIndirect())
1739 DwarfExpr.EmitOp(dwarf::DW_OP_deref);
1740 }
1741 }
1742 // else ... ignore constant fp. There is not any good way to
1743 // to represent them here in dwarf.
1744 // FIXME: ^
1745 }
1746
emitDebugLocEntryLocation(const DebugLocEntry & Entry)1747 void DwarfDebug::emitDebugLocEntryLocation(const DebugLocEntry &Entry) {
1748 Asm->OutStreamer.AddComment("Loc expr size");
1749 MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
1750 MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
1751 Asm->EmitLabelDifference(end, begin, 2);
1752 Asm->OutStreamer.EmitLabel(begin);
1753 // Emit the entry.
1754 APByteStreamer Streamer(*Asm);
1755 emitDebugLocEntry(Streamer, Entry);
1756 // Close the range.
1757 Asm->OutStreamer.EmitLabel(end);
1758 }
1759
1760 // Emit locations into the debug loc section.
emitDebugLoc()1761 void DwarfDebug::emitDebugLoc() {
1762 // Start the dwarf loc section.
1763 Asm->OutStreamer.SwitchSection(
1764 Asm->getObjFileLowering().getDwarfLocSection());
1765 unsigned char Size = Asm->getDataLayout().getPointerSize();
1766 for (const auto &DebugLoc : DotDebugLocEntries) {
1767 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1768 const DwarfCompileUnit *CU = DebugLoc.CU;
1769 for (const auto &Entry : DebugLoc.List) {
1770 // Set up the range. This range is relative to the entry point of the
1771 // compile unit. This is a hard coded 0 for low_pc when we're emitting
1772 // ranges, or the DW_AT_low_pc on the compile unit otherwise.
1773 if (auto *Base = CU->getBaseAddress()) {
1774 Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
1775 Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
1776 } else {
1777 Asm->OutStreamer.EmitSymbolValue(Entry.getBeginSym(), Size);
1778 Asm->OutStreamer.EmitSymbolValue(Entry.getEndSym(), Size);
1779 }
1780
1781 emitDebugLocEntryLocation(Entry);
1782 }
1783 Asm->OutStreamer.EmitIntValue(0, Size);
1784 Asm->OutStreamer.EmitIntValue(0, Size);
1785 }
1786 }
1787
emitDebugLocDWO()1788 void DwarfDebug::emitDebugLocDWO() {
1789 Asm->OutStreamer.SwitchSection(
1790 Asm->getObjFileLowering().getDwarfLocDWOSection());
1791 for (const auto &DebugLoc : DotDebugLocEntries) {
1792 Asm->OutStreamer.EmitLabel(DebugLoc.Label);
1793 for (const auto &Entry : DebugLoc.List) {
1794 // Just always use start_length for now - at least that's one address
1795 // rather than two. We could get fancier and try to, say, reuse an
1796 // address we know we've emitted elsewhere (the start of the function?
1797 // The start of the CU or CU subrange that encloses this range?)
1798 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry);
1799 unsigned idx = AddrPool.getIndex(Entry.getBeginSym());
1800 Asm->EmitULEB128(idx);
1801 Asm->EmitLabelDifference(Entry.getEndSym(), Entry.getBeginSym(), 4);
1802
1803 emitDebugLocEntryLocation(Entry);
1804 }
1805 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry);
1806 }
1807 }
1808
1809 struct ArangeSpan {
1810 const MCSymbol *Start, *End;
1811 };
1812
1813 // Emit a debug aranges section, containing a CU lookup for any
1814 // address we can tie back to a CU.
emitDebugARanges()1815 void DwarfDebug::emitDebugARanges() {
1816 // Start the dwarf aranges section.
1817 Asm->OutStreamer.SwitchSection(
1818 Asm->getObjFileLowering().getDwarfARangesSection());
1819
1820 typedef DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> SpansType;
1821
1822 SpansType Spans;
1823
1824 // Build a list of sections used.
1825 std::vector<const MCSection *> Sections;
1826 for (const auto &it : SectionMap) {
1827 const MCSection *Section = it.first;
1828 Sections.push_back(Section);
1829 }
1830
1831 // Sort the sections into order.
1832 // This is only done to ensure consistent output order across different runs.
1833 std::sort(Sections.begin(), Sections.end(), SectionSort);
1834
1835 // Build a set of address spans, sorted by CU.
1836 for (const MCSection *Section : Sections) {
1837 SmallVector<SymbolCU, 8> &List = SectionMap[Section];
1838 if (List.size() < 2)
1839 continue;
1840
1841 // Sort the symbols by offset within the section.
1842 std::sort(List.begin(), List.end(),
1843 [&](const SymbolCU &A, const SymbolCU &B) {
1844 unsigned IA = A.Sym ? Asm->OutStreamer.GetSymbolOrder(A.Sym) : 0;
1845 unsigned IB = B.Sym ? Asm->OutStreamer.GetSymbolOrder(B.Sym) : 0;
1846
1847 // Symbols with no order assigned should be placed at the end.
1848 // (e.g. section end labels)
1849 if (IA == 0)
1850 return false;
1851 if (IB == 0)
1852 return true;
1853 return IA < IB;
1854 });
1855
1856 // If we have no section (e.g. common), just write out
1857 // individual spans for each symbol.
1858 if (!Section) {
1859 for (const SymbolCU &Cur : List) {
1860 ArangeSpan Span;
1861 Span.Start = Cur.Sym;
1862 Span.End = nullptr;
1863 if (Cur.CU)
1864 Spans[Cur.CU].push_back(Span);
1865 }
1866 } else {
1867 // Build spans between each label.
1868 const MCSymbol *StartSym = List[0].Sym;
1869 for (size_t n = 1, e = List.size(); n < e; n++) {
1870 const SymbolCU &Prev = List[n - 1];
1871 const SymbolCU &Cur = List[n];
1872
1873 // Try and build the longest span we can within the same CU.
1874 if (Cur.CU != Prev.CU) {
1875 ArangeSpan Span;
1876 Span.Start = StartSym;
1877 Span.End = Cur.Sym;
1878 Spans[Prev.CU].push_back(Span);
1879 StartSym = Cur.Sym;
1880 }
1881 }
1882 }
1883 }
1884
1885 unsigned PtrSize = Asm->getDataLayout().getPointerSize();
1886
1887 // Build a list of CUs used.
1888 std::vector<DwarfCompileUnit *> CUs;
1889 for (const auto &it : Spans) {
1890 DwarfCompileUnit *CU = it.first;
1891 CUs.push_back(CU);
1892 }
1893
1894 // Sort the CU list (again, to ensure consistent output order).
1895 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
1896 return A->getUniqueID() < B->getUniqueID();
1897 });
1898
1899 // Emit an arange table for each CU we used.
1900 for (DwarfCompileUnit *CU : CUs) {
1901 std::vector<ArangeSpan> &List = Spans[CU];
1902
1903 // Describe the skeleton CU's offset and length, not the dwo file's.
1904 if (auto *Skel = CU->getSkeleton())
1905 CU = Skel;
1906
1907 // Emit size of content not including length itself.
1908 unsigned ContentSize =
1909 sizeof(int16_t) + // DWARF ARange version number
1910 sizeof(int32_t) + // Offset of CU in the .debug_info section
1911 sizeof(int8_t) + // Pointer Size (in bytes)
1912 sizeof(int8_t); // Segment Size (in bytes)
1913
1914 unsigned TupleSize = PtrSize * 2;
1915
1916 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple.
1917 unsigned Padding =
1918 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize);
1919
1920 ContentSize += Padding;
1921 ContentSize += (List.size() + 1) * TupleSize;
1922
1923 // For each compile unit, write the list of spans it covers.
1924 Asm->OutStreamer.AddComment("Length of ARange Set");
1925 Asm->EmitInt32(ContentSize);
1926 Asm->OutStreamer.AddComment("DWARF Arange version number");
1927 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
1928 Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
1929 Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
1930 Asm->OutStreamer.AddComment("Address Size (in bytes)");
1931 Asm->EmitInt8(PtrSize);
1932 Asm->OutStreamer.AddComment("Segment Size (in bytes)");
1933 Asm->EmitInt8(0);
1934
1935 Asm->OutStreamer.EmitFill(Padding, 0xff);
1936
1937 for (const ArangeSpan &Span : List) {
1938 Asm->EmitLabelReference(Span.Start, PtrSize);
1939
1940 // Calculate the size as being from the span start to it's end.
1941 if (Span.End) {
1942 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize);
1943 } else {
1944 // For symbols without an end marker (e.g. common), we
1945 // write a single arange entry containing just that one symbol.
1946 uint64_t Size = SymSize[Span.Start];
1947 if (Size == 0)
1948 Size = 1;
1949
1950 Asm->OutStreamer.EmitIntValue(Size, PtrSize);
1951 }
1952 }
1953
1954 Asm->OutStreamer.AddComment("ARange terminator");
1955 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1956 Asm->OutStreamer.EmitIntValue(0, PtrSize);
1957 }
1958 }
1959
1960 // Emit visible names into a debug ranges section.
emitDebugRanges()1961 void DwarfDebug::emitDebugRanges() {
1962 // Start the dwarf ranges section.
1963 Asm->OutStreamer.SwitchSection(
1964 Asm->getObjFileLowering().getDwarfRangesSection());
1965
1966 // Size for our labels.
1967 unsigned char Size = Asm->getDataLayout().getPointerSize();
1968
1969 // Grab the specific ranges for the compile units in the module.
1970 for (const auto &I : CUMap) {
1971 DwarfCompileUnit *TheCU = I.second;
1972
1973 if (auto *Skel = TheCU->getSkeleton())
1974 TheCU = Skel;
1975
1976 // Iterate over the misc ranges for the compile units in the module.
1977 for (const RangeSpanList &List : TheCU->getRangeLists()) {
1978 // Emit our symbol so we can find the beginning of the range.
1979 Asm->OutStreamer.EmitLabel(List.getSym());
1980
1981 for (const RangeSpan &Range : List.getRanges()) {
1982 const MCSymbol *Begin = Range.getStart();
1983 const MCSymbol *End = Range.getEnd();
1984 assert(Begin && "Range without a begin symbol?");
1985 assert(End && "Range without an end symbol?");
1986 if (auto *Base = TheCU->getBaseAddress()) {
1987 Asm->EmitLabelDifference(Begin, Base, Size);
1988 Asm->EmitLabelDifference(End, Base, Size);
1989 } else {
1990 Asm->OutStreamer.EmitSymbolValue(Begin, Size);
1991 Asm->OutStreamer.EmitSymbolValue(End, Size);
1992 }
1993 }
1994
1995 // And terminate the list with two 0 values.
1996 Asm->OutStreamer.EmitIntValue(0, Size);
1997 Asm->OutStreamer.EmitIntValue(0, Size);
1998 }
1999 }
2000 }
2001
2002 // DWARF5 Experimental Separate Dwarf emitters.
2003
initSkeletonUnit(const DwarfUnit & U,DIE & Die,std::unique_ptr<DwarfUnit> NewU)2004 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
2005 std::unique_ptr<DwarfUnit> NewU) {
2006 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
2007 U.getCUNode().getSplitDebugFilename());
2008
2009 if (!CompilationDir.empty())
2010 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
2011
2012 addGnuPubAttributes(*NewU, Die);
2013
2014 SkeletonHolder.addUnit(std::move(NewU));
2015 }
2016
2017 // This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
2018 // DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
2019 // DW_AT_addr_base, DW_AT_ranges_base.
constructSkeletonCU(const DwarfCompileUnit & CU)2020 DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) {
2021
2022 auto OwnedUnit = make_unique<DwarfCompileUnit>(
2023 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder);
2024 DwarfCompileUnit &NewCU = *OwnedUnit;
2025 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
2026 DwarfInfoSectionSym);
2027
2028 NewCU.initStmtList(DwarfLineSectionSym);
2029
2030 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit));
2031
2032 return NewCU;
2033 }
2034
2035 // Emit the .debug_info.dwo section for separated dwarf. This contains the
2036 // compile units that would normally be in debug_info.
emitDebugInfoDWO()2037 void DwarfDebug::emitDebugInfoDWO() {
2038 assert(useSplitDwarf() && "No split dwarf debug info?");
2039 // Don't pass an abbrev symbol, using a constant zero instead so as not to
2040 // emit relocations into the dwo file.
2041 InfoHolder.emitUnits(/* AbbrevSymbol */ nullptr);
2042 }
2043
2044 // Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
2045 // abbreviations for the .debug_info.dwo section.
emitDebugAbbrevDWO()2046 void DwarfDebug::emitDebugAbbrevDWO() {
2047 assert(useSplitDwarf() && "No split dwarf?");
2048 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection());
2049 }
2050
emitDebugLineDWO()2051 void DwarfDebug::emitDebugLineDWO() {
2052 assert(useSplitDwarf() && "No split dwarf?");
2053 Asm->OutStreamer.SwitchSection(
2054 Asm->getObjFileLowering().getDwarfLineDWOSection());
2055 SplitTypeUnitFileTable.Emit(Asm->OutStreamer);
2056 }
2057
2058 // Emit the .debug_str.dwo section for separated dwarf. This contains the
2059 // string section and is identical in format to traditional .debug_str
2060 // sections.
emitDebugStrDWO()2061 void DwarfDebug::emitDebugStrDWO() {
2062 assert(useSplitDwarf() && "No split dwarf?");
2063 const MCSection *OffSec =
2064 Asm->getObjFileLowering().getDwarfStrOffDWOSection();
2065 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
2066 OffSec);
2067 }
2068
getDwoLineTable(const DwarfCompileUnit & CU)2069 MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) {
2070 if (!useSplitDwarf())
2071 return nullptr;
2072 if (SingleCU)
2073 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode().getDirectory());
2074 return &SplitTypeUnitFileTable;
2075 }
2076
makeTypeSignature(StringRef Identifier)2077 static uint64_t makeTypeSignature(StringRef Identifier) {
2078 MD5 Hash;
2079 Hash.update(Identifier);
2080 // ... take the least significant 8 bytes and return those. Our MD5
2081 // implementation always returns its results in little endian, swap bytes
2082 // appropriately.
2083 MD5::MD5Result Result;
2084 Hash.final(Result);
2085 return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
2086 }
2087
addDwarfTypeUnitType(DwarfCompileUnit & CU,StringRef Identifier,DIE & RefDie,DICompositeType CTy)2088 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
2089 StringRef Identifier, DIE &RefDie,
2090 DICompositeType CTy) {
2091 // Fast path if we're building some type units and one has already used the
2092 // address pool we know we're going to throw away all this work anyway, so
2093 // don't bother building dependent types.
2094 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
2095 return;
2096
2097 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
2098 if (TU) {
2099 CU.addDIETypeSignature(RefDie, *TU);
2100 return;
2101 }
2102
2103 bool TopLevelType = TypeUnitsUnderConstruction.empty();
2104 AddrPool.resetUsedFlag();
2105
2106 auto OwnedUnit = make_unique<DwarfTypeUnit>(
2107 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
2108 this, &InfoHolder, getDwoLineTable(CU));
2109 DwarfTypeUnit &NewTU = *OwnedUnit;
2110 DIE &UnitDie = NewTU.getUnitDie();
2111 TU = &NewTU;
2112 TypeUnitsUnderConstruction.push_back(
2113 std::make_pair(std::move(OwnedUnit), CTy));
2114
2115 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
2116 CU.getLanguage());
2117
2118 uint64_t Signature = makeTypeSignature(Identifier);
2119 NewTU.setTypeSignature(Signature);
2120
2121 if (useSplitDwarf())
2122 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
2123 else {
2124 CU.applyStmtList(UnitDie);
2125 NewTU.initSection(
2126 Asm->getObjFileLowering().getDwarfTypesSection(Signature));
2127 }
2128
2129 NewTU.setType(NewTU.createTypeDIE(CTy));
2130
2131 if (TopLevelType) {
2132 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction);
2133 TypeUnitsUnderConstruction.clear();
2134
2135 // Types referencing entries in the address table cannot be placed in type
2136 // units.
2137 if (AddrPool.hasBeenUsed()) {
2138
2139 // Remove all the types built while building this type.
2140 // This is pessimistic as some of these types might not be dependent on
2141 // the type that used an address.
2142 for (const auto &TU : TypeUnitsToAdd)
2143 DwarfTypeUnits.erase(TU.second);
2144
2145 // Construct this type in the CU directly.
2146 // This is inefficient because all the dependent types will be rebuilt
2147 // from scratch, including building them in type units, discovering that
2148 // they depend on addresses, throwing them out and rebuilding them.
2149 CU.constructTypeDIE(RefDie, CTy);
2150 return;
2151 }
2152
2153 // If the type wasn't dependent on fission addresses, finish adding the type
2154 // and all its dependent types.
2155 for (auto &TU : TypeUnitsToAdd)
2156 InfoHolder.addUnit(std::move(TU.first));
2157 }
2158 CU.addDIETypeSignature(RefDie, NewTU);
2159 }
2160
2161 // Accelerator table mutators - add each name along with its companion
2162 // DIE to the proper table while ensuring that the name that we're going
2163 // to reference is in the string table. We do this since the names we
2164 // add may not only be identical to the names in the DIE.
addAccelName(StringRef Name,const DIE & Die)2165 void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) {
2166 if (!useDwarfAccelTables())
2167 return;
2168 AccelNames.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2169 &Die);
2170 }
2171
addAccelObjC(StringRef Name,const DIE & Die)2172 void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) {
2173 if (!useDwarfAccelTables())
2174 return;
2175 AccelObjC.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2176 &Die);
2177 }
2178
addAccelNamespace(StringRef Name,const DIE & Die)2179 void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) {
2180 if (!useDwarfAccelTables())
2181 return;
2182 AccelNamespace.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2183 &Die);
2184 }
2185
addAccelType(StringRef Name,const DIE & Die,char Flags)2186 void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) {
2187 if (!useDwarfAccelTables())
2188 return;
2189 AccelTypes.AddName(Name, InfoHolder.getStringPool().getSymbol(*Asm, Name),
2190 &Die);
2191 }
2192