DwarfDebug.cpp revision 288943
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 "DebugLocEntry.h" 18#include "DwarfCompileUnit.h" 19#include "DwarfExpression.h" 20#include "DwarfUnit.h" 21#include "llvm/ADT/STLExtras.h" 22#include "llvm/ADT/Statistic.h" 23#include "llvm/ADT/StringExtras.h" 24#include "llvm/ADT/Triple.h" 25#include "llvm/CodeGen/DIE.h" 26#include "llvm/CodeGen/MachineFunction.h" 27#include "llvm/CodeGen/MachineModuleInfo.h" 28#include "llvm/IR/Constants.h" 29#include "llvm/IR/DIBuilder.h" 30#include "llvm/IR/DataLayout.h" 31#include "llvm/IR/DebugInfo.h" 32#include "llvm/IR/Instructions.h" 33#include "llvm/IR/Module.h" 34#include "llvm/IR/ValueHandle.h" 35#include "llvm/MC/MCAsmInfo.h" 36#include "llvm/MC/MCSection.h" 37#include "llvm/MC/MCStreamer.h" 38#include "llvm/MC/MCSymbol.h" 39#include "llvm/Support/CommandLine.h" 40#include "llvm/Support/Debug.h" 41#include "llvm/Support/Dwarf.h" 42#include "llvm/Support/Endian.h" 43#include "llvm/Support/ErrorHandling.h" 44#include "llvm/Support/FormattedStream.h" 45#include "llvm/Support/LEB128.h" 46#include "llvm/Support/MD5.h" 47#include "llvm/Support/Path.h" 48#include "llvm/Support/Timer.h" 49#include "llvm/Support/raw_ostream.h" 50#include "llvm/Target/TargetFrameLowering.h" 51#include "llvm/Target/TargetLoweringObjectFile.h" 52#include "llvm/Target/TargetMachine.h" 53#include "llvm/Target/TargetOptions.h" 54#include "llvm/Target/TargetRegisterInfo.h" 55#include "llvm/Target/TargetSubtargetInfo.h" 56using namespace llvm; 57 58#define DEBUG_TYPE "dwarfdebug" 59 60static cl::opt<bool> 61DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden, 62 cl::desc("Disable debug info printing")); 63 64static cl::opt<bool> UnknownLocations( 65 "use-unknown-locations", cl::Hidden, 66 cl::desc("Make an absence of debug location information explicit."), 67 cl::init(false)); 68 69static cl::opt<bool> 70GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden, 71 cl::desc("Generate GNU-style pubnames and pubtypes"), 72 cl::init(false)); 73 74static cl::opt<bool> GenerateARangeSection("generate-arange-section", 75 cl::Hidden, 76 cl::desc("Generate dwarf aranges"), 77 cl::init(false)); 78 79namespace { 80enum DefaultOnOff { Default, Enable, Disable }; 81} 82 83static cl::opt<DefaultOnOff> 84DwarfAccelTables("dwarf-accel-tables", cl::Hidden, 85 cl::desc("Output prototype dwarf accelerator tables."), 86 cl::values(clEnumVal(Default, "Default for platform"), 87 clEnumVal(Enable, "Enabled"), 88 clEnumVal(Disable, "Disabled"), clEnumValEnd), 89 cl::init(Default)); 90 91static cl::opt<DefaultOnOff> 92SplitDwarf("split-dwarf", cl::Hidden, 93 cl::desc("Output DWARF5 split debug info."), 94 cl::values(clEnumVal(Default, "Default for platform"), 95 clEnumVal(Enable, "Enabled"), 96 clEnumVal(Disable, "Disabled"), clEnumValEnd), 97 cl::init(Default)); 98 99static cl::opt<DefaultOnOff> 100DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden, 101 cl::desc("Generate DWARF pubnames and pubtypes sections"), 102 cl::values(clEnumVal(Default, "Default for platform"), 103 clEnumVal(Enable, "Enabled"), 104 clEnumVal(Disable, "Disabled"), clEnumValEnd), 105 cl::init(Default)); 106 107static const char *const DWARFGroupName = "DWARF Emission"; 108static const char *const DbgTimerName = "DWARF Debug Writer"; 109 110void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) { 111 BS.EmitInt8( 112 Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op) 113 : dwarf::OperationEncodingString(Op)); 114} 115 116void DebugLocDwarfExpression::EmitSigned(int64_t Value) { 117 BS.EmitSLEB128(Value, Twine(Value)); 118} 119 120void DebugLocDwarfExpression::EmitUnsigned(uint64_t Value) { 121 BS.EmitULEB128(Value, Twine(Value)); 122} 123 124bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) { 125 // This information is not available while emitting .debug_loc entries. 126 return false; 127} 128 129//===----------------------------------------------------------------------===// 130 131/// resolve - Look in the DwarfDebug map for the MDNode that 132/// corresponds to the reference. 133template <typename T> T *DbgVariable::resolve(TypedDINodeRef<T> Ref) const { 134 return DD->resolve(Ref); 135} 136 137bool DbgVariable::isBlockByrefVariable() const { 138 assert(Var && "Invalid complex DbgVariable!"); 139 return Var->getType() 140 .resolve(DD->getTypeIdentifierMap()) 141 ->isBlockByrefStruct(); 142} 143 144const DIType *DbgVariable::getType() const { 145 DIType *Ty = Var->getType().resolve(DD->getTypeIdentifierMap()); 146 // FIXME: isBlockByrefVariable should be reformulated in terms of complex 147 // addresses instead. 148 if (Ty->isBlockByrefStruct()) { 149 /* Byref variables, in Blocks, are declared by the programmer as 150 "SomeType VarName;", but the compiler creates a 151 __Block_byref_x_VarName struct, and gives the variable VarName 152 either the struct, or a pointer to the struct, as its type. This 153 is necessary for various behind-the-scenes things the compiler 154 needs to do with by-reference variables in blocks. 155 156 However, as far as the original *programmer* is concerned, the 157 variable should still have type 'SomeType', as originally declared. 158 159 The following function dives into the __Block_byref_x_VarName 160 struct to find the original type of the variable. This will be 161 passed back to the code generating the type for the Debug 162 Information Entry for the variable 'VarName'. 'VarName' will then 163 have the original type 'SomeType' in its debug information. 164 165 The original type 'SomeType' will be the type of the field named 166 'VarName' inside the __Block_byref_x_VarName struct. 167 168 NOTE: In order for this to not completely fail on the debugger 169 side, the Debug Information Entry for the variable VarName needs to 170 have a DW_AT_location that tells the debugger how to unwind through 171 the pointers and __Block_byref_x_VarName struct to find the actual 172 value of the variable. The function addBlockByrefType does this. */ 173 DIType *subType = Ty; 174 uint16_t tag = Ty->getTag(); 175 176 if (tag == dwarf::DW_TAG_pointer_type) 177 subType = resolve(cast<DIDerivedType>(Ty)->getBaseType()); 178 179 auto Elements = cast<DICompositeTypeBase>(subType)->getElements(); 180 for (unsigned i = 0, N = Elements.size(); i < N; ++i) { 181 auto *DT = cast<DIDerivedTypeBase>(Elements[i]); 182 if (getName() == DT->getName()) 183 return resolve(DT->getBaseType()); 184 } 185 } 186 return Ty; 187} 188 189static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = { 190 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4), 191 DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2), 192 DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)}; 193 194DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M) 195 : Asm(A), MMI(Asm->MMI), DebugLocs(A->OutStreamer->isVerboseAsm()), 196 PrevLabel(nullptr), InfoHolder(A, "info_string", DIEValueAllocator), 197 UsedNonDefaultText(false), 198 SkeletonHolder(A, "skel_string", DIEValueAllocator), 199 IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()), 200 IsPS4(Triple(A->getTargetTriple()).isPS4()), 201 AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, 202 dwarf::DW_FORM_data4)), 203 AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, 204 dwarf::DW_FORM_data4)), 205 AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, 206 dwarf::DW_FORM_data4)), 207 AccelTypes(TypeAtoms) { 208 209 CurFn = nullptr; 210 CurMI = nullptr; 211 212 // Turn on accelerator tables for Darwin by default, pubnames by 213 // default for non-Darwin/PS4, and handle split dwarf. 214 if (DwarfAccelTables == Default) 215 HasDwarfAccelTables = IsDarwin; 216 else 217 HasDwarfAccelTables = DwarfAccelTables == Enable; 218 219 if (SplitDwarf == Default) 220 HasSplitDwarf = false; 221 else 222 HasSplitDwarf = SplitDwarf == Enable; 223 224 if (DwarfPubSections == Default) 225 HasDwarfPubSections = !IsDarwin && !IsPS4; 226 else 227 HasDwarfPubSections = DwarfPubSections == Enable; 228 229 unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion; 230 DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber 231 : MMI->getModule()->getDwarfVersion(); 232 233 // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3). 234 // Everybody else uses GNU's. 235 UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3; 236 237 Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion); 238 239 { 240 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 241 beginModule(); 242 } 243} 244 245// Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h. 246DwarfDebug::~DwarfDebug() { } 247 248static bool isObjCClass(StringRef Name) { 249 return Name.startswith("+") || Name.startswith("-"); 250} 251 252static bool hasObjCCategory(StringRef Name) { 253 if (!isObjCClass(Name)) 254 return false; 255 256 return Name.find(") ") != StringRef::npos; 257} 258 259static void getObjCClassCategory(StringRef In, StringRef &Class, 260 StringRef &Category) { 261 if (!hasObjCCategory(In)) { 262 Class = In.slice(In.find('[') + 1, In.find(' ')); 263 Category = ""; 264 return; 265 } 266 267 Class = In.slice(In.find('[') + 1, In.find('(')); 268 Category = In.slice(In.find('[') + 1, In.find(' ')); 269 return; 270} 271 272static StringRef getObjCMethodName(StringRef In) { 273 return In.slice(In.find(' ') + 1, In.find(']')); 274} 275 276// Add the various names to the Dwarf accelerator table names. 277// TODO: Determine whether or not we should add names for programs 278// that do not have a DW_AT_name or DW_AT_linkage_name field - this 279// is only slightly different than the lookup of non-standard ObjC names. 280void DwarfDebug::addSubprogramNames(const DISubprogram *SP, DIE &Die) { 281 if (!SP->isDefinition()) 282 return; 283 addAccelName(SP->getName(), Die); 284 285 // If the linkage name is different than the name, go ahead and output 286 // that as well into the name table. 287 if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName()) 288 addAccelName(SP->getLinkageName(), Die); 289 290 // If this is an Objective-C selector name add it to the ObjC accelerator 291 // too. 292 if (isObjCClass(SP->getName())) { 293 StringRef Class, Category; 294 getObjCClassCategory(SP->getName(), Class, Category); 295 addAccelObjC(Class, Die); 296 if (Category != "") 297 addAccelObjC(Category, Die); 298 // Also add the base method name to the name table. 299 addAccelName(getObjCMethodName(SP->getName()), Die); 300 } 301} 302 303/// isSubprogramContext - Return true if Context is either a subprogram 304/// or another context nested inside a subprogram. 305bool DwarfDebug::isSubprogramContext(const MDNode *Context) { 306 if (!Context) 307 return false; 308 if (isa<DISubprogram>(Context)) 309 return true; 310 if (auto *T = dyn_cast<DIType>(Context)) 311 return isSubprogramContext(resolve(T->getScope())); 312 return false; 313} 314 315/// Check whether we should create a DIE for the given Scope, return true 316/// if we don't create a DIE (the corresponding DIE is null). 317bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) { 318 if (Scope->isAbstractScope()) 319 return false; 320 321 // We don't create a DIE if there is no Range. 322 const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges(); 323 if (Ranges.empty()) 324 return true; 325 326 if (Ranges.size() > 1) 327 return false; 328 329 // We don't create a DIE if we have a single Range and the end label 330 // is null. 331 return !getLabelAfterInsn(Ranges.front().second); 332} 333 334template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) { 335 F(CU); 336 if (auto *SkelCU = CU.getSkeleton()) 337 F(*SkelCU); 338} 339 340void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) { 341 assert(Scope && Scope->getScopeNode()); 342 assert(Scope->isAbstractScope()); 343 assert(!Scope->getInlinedAt()); 344 345 const MDNode *SP = Scope->getScopeNode(); 346 347 ProcessedSPNodes.insert(SP); 348 349 // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram 350 // was inlined from another compile unit. 351 auto &CU = SPMap[SP]; 352 forBothCUs(*CU, [&](DwarfCompileUnit &CU) { 353 CU.constructAbstractSubprogramScopeDIE(Scope); 354 }); 355} 356 357void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const { 358 if (!GenerateGnuPubSections) 359 return; 360 361 U.addFlag(D, dwarf::DW_AT_GNU_pubnames); 362} 363 364// Create new DwarfCompileUnit for the given metadata node with tag 365// DW_TAG_compile_unit. 366DwarfCompileUnit & 367DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) { 368 StringRef FN = DIUnit->getFilename(); 369 CompilationDir = DIUnit->getDirectory(); 370 371 auto OwnedUnit = make_unique<DwarfCompileUnit>( 372 InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder); 373 DwarfCompileUnit &NewCU = *OwnedUnit; 374 DIE &Die = NewCU.getUnitDie(); 375 InfoHolder.addUnit(std::move(OwnedUnit)); 376 if (useSplitDwarf()) 377 NewCU.setSkeleton(constructSkeletonCU(NewCU)); 378 379 // LTO with assembly output shares a single line table amongst multiple CUs. 380 // To avoid the compilation directory being ambiguous, let the line table 381 // explicitly describe the directory of all files, never relying on the 382 // compilation directory. 383 if (!Asm->OutStreamer->hasRawTextSupport() || SingleCU) 384 Asm->OutStreamer->getContext().setMCLineTableCompilationDir( 385 NewCU.getUniqueID(), CompilationDir); 386 387 NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer()); 388 NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2, 389 DIUnit->getSourceLanguage()); 390 NewCU.addString(Die, dwarf::DW_AT_name, FN); 391 392 if (!useSplitDwarf()) { 393 NewCU.initStmtList(); 394 395 // If we're using split dwarf the compilation dir is going to be in the 396 // skeleton CU and so we don't need to duplicate it here. 397 if (!CompilationDir.empty()) 398 NewCU.addString(Die, dwarf::DW_AT_comp_dir, CompilationDir); 399 400 addGnuPubAttributes(NewCU, Die); 401 } 402 403 if (DIUnit->isOptimized()) 404 NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized); 405 406 StringRef Flags = DIUnit->getFlags(); 407 if (!Flags.empty()) 408 NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags); 409 410 if (unsigned RVer = DIUnit->getRuntimeVersion()) 411 NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers, 412 dwarf::DW_FORM_data1, RVer); 413 414 if (useSplitDwarf()) 415 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection()); 416 else 417 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection()); 418 419 CUMap.insert(std::make_pair(DIUnit, &NewCU)); 420 CUDieMap.insert(std::make_pair(&Die, &NewCU)); 421 return NewCU; 422} 423 424void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU, 425 const DIImportedEntity *N) { 426 if (DIE *D = TheCU.getOrCreateContextDIE(N->getScope())) 427 D->addChild(TheCU.constructImportedEntityDIE(N)); 428} 429 430// Emit all Dwarf sections that should come prior to the content. Create 431// global DIEs and emit initial debug info sections. This is invoked by 432// the target AsmPrinter. 433void DwarfDebug::beginModule() { 434 if (DisableDebugInfoPrinting) 435 return; 436 437 const Module *M = MMI->getModule(); 438 439 FunctionDIs = makeSubprogramMap(*M); 440 441 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu"); 442 if (!CU_Nodes) 443 return; 444 TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes); 445 446 SingleCU = CU_Nodes->getNumOperands() == 1; 447 448 for (MDNode *N : CU_Nodes->operands()) { 449 auto *CUNode = cast<DICompileUnit>(N); 450 DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode); 451 for (auto *IE : CUNode->getImportedEntities()) 452 ScopesWithImportedEntities.push_back(std::make_pair(IE->getScope(), IE)); 453 // Stable sort to preserve the order of appearance of imported entities. 454 // This is to avoid out-of-order processing of interdependent declarations 455 // within the same scope, e.g. { namespace A = base; namespace B = A; } 456 std::stable_sort(ScopesWithImportedEntities.begin(), 457 ScopesWithImportedEntities.end(), less_first()); 458 for (auto *GV : CUNode->getGlobalVariables()) 459 CU.getOrCreateGlobalVariableDIE(GV); 460 for (auto *SP : CUNode->getSubprograms()) 461 SPMap.insert(std::make_pair(SP, &CU)); 462 for (auto *Ty : CUNode->getEnumTypes()) { 463 // The enum types array by design contains pointers to 464 // MDNodes rather than DIRefs. Unique them here. 465 CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef()))); 466 } 467 for (auto *Ty : CUNode->getRetainedTypes()) { 468 // The retained types array by design contains pointers to 469 // MDNodes rather than DIRefs. Unique them here. 470 CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef()))); 471 } 472 // Emit imported_modules last so that the relevant context is already 473 // available. 474 for (auto *IE : CUNode->getImportedEntities()) 475 constructAndAddImportedEntityDIE(CU, IE); 476 } 477 478 // Tell MMI that we have debug info. 479 MMI->setDebugInfoAvailability(true); 480} 481 482void DwarfDebug::finishVariableDefinitions() { 483 for (const auto &Var : ConcreteVariables) { 484 DIE *VariableDie = Var->getDIE(); 485 assert(VariableDie); 486 // FIXME: Consider the time-space tradeoff of just storing the unit pointer 487 // in the ConcreteVariables list, rather than looking it up again here. 488 // DIE::getUnit isn't simple - it walks parent pointers, etc. 489 DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit()); 490 assert(Unit); 491 DbgVariable *AbsVar = getExistingAbstractVariable( 492 InlinedVariable(Var->getVariable(), Var->getInlinedAt())); 493 if (AbsVar && AbsVar->getDIE()) { 494 Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin, 495 *AbsVar->getDIE()); 496 } else 497 Unit->applyVariableAttributes(*Var, *VariableDie); 498 } 499} 500 501void DwarfDebug::finishSubprogramDefinitions() { 502 for (const auto &P : SPMap) 503 forBothCUs(*P.second, [&](DwarfCompileUnit &CU) { 504 CU.finishSubprogramDefinition(cast<DISubprogram>(P.first)); 505 }); 506} 507 508 509// Collect info for variables that were optimized out. 510void DwarfDebug::collectDeadVariables() { 511 const Module *M = MMI->getModule(); 512 513 if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) { 514 for (MDNode *N : CU_Nodes->operands()) { 515 auto *TheCU = cast<DICompileUnit>(N); 516 // Construct subprogram DIE and add variables DIEs. 517 DwarfCompileUnit *SPCU = 518 static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU)); 519 assert(SPCU && "Unable to find Compile Unit!"); 520 for (auto *SP : TheCU->getSubprograms()) { 521 if (ProcessedSPNodes.count(SP) != 0) 522 continue; 523 SPCU->collectDeadVariables(SP); 524 } 525 } 526 } 527} 528 529void DwarfDebug::finalizeModuleInfo() { 530 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 531 532 finishSubprogramDefinitions(); 533 534 finishVariableDefinitions(); 535 536 // Collect info for variables that were optimized out. 537 collectDeadVariables(); 538 539 // Handle anything that needs to be done on a per-unit basis after 540 // all other generation. 541 for (const auto &P : CUMap) { 542 auto &TheCU = *P.second; 543 // Emit DW_AT_containing_type attribute to connect types with their 544 // vtable holding type. 545 TheCU.constructContainingTypeDIEs(); 546 547 // Add CU specific attributes if we need to add any. 548 // If we're splitting the dwarf out now that we've got the entire 549 // CU then add the dwo id to it. 550 auto *SkCU = TheCU.getSkeleton(); 551 if (useSplitDwarf()) { 552 // Emit a unique identifier for this CU. 553 uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie()); 554 TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id, 555 dwarf::DW_FORM_data8, ID); 556 SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id, 557 dwarf::DW_FORM_data8, ID); 558 559 // We don't keep track of which addresses are used in which CU so this 560 // is a bit pessimistic under LTO. 561 if (!AddrPool.isEmpty()) { 562 const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol(); 563 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base, 564 Sym, Sym); 565 } 566 if (!SkCU->getRangeLists().empty()) { 567 const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol(); 568 SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base, 569 Sym, Sym); 570 } 571 } 572 573 // If we have code split among multiple sections or non-contiguous 574 // ranges of code then emit a DW_AT_ranges attribute on the unit that will 575 // remain in the .o file, otherwise add a DW_AT_low_pc. 576 // FIXME: We should use ranges allow reordering of code ala 577 // .subsections_via_symbols in mach-o. This would mean turning on 578 // ranges for all subprogram DIEs for mach-o. 579 DwarfCompileUnit &U = SkCU ? *SkCU : TheCU; 580 if (unsigned NumRanges = TheCU.getRanges().size()) { 581 if (NumRanges > 1) 582 // A DW_AT_low_pc attribute may also be specified in combination with 583 // DW_AT_ranges to specify the default base address for use in 584 // location lists (see Section 2.6.2) and range lists (see Section 585 // 2.17.3). 586 U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0); 587 else 588 U.setBaseAddress(TheCU.getRanges().front().getStart()); 589 U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges()); 590 } 591 } 592 593 // Compute DIE offsets and sizes. 594 InfoHolder.computeSizeAndOffsets(); 595 if (useSplitDwarf()) 596 SkeletonHolder.computeSizeAndOffsets(); 597} 598 599// Emit all Dwarf sections that should come after the content. 600void DwarfDebug::endModule() { 601 assert(CurFn == nullptr); 602 assert(CurMI == nullptr); 603 604 // If we aren't actually generating debug info (check beginModule - 605 // conditionalized on !DisableDebugInfoPrinting and the presence of the 606 // llvm.dbg.cu metadata node) 607 if (!MMI->hasDebugInfo()) 608 return; 609 610 // Finalize the debug info for the module. 611 finalizeModuleInfo(); 612 613 emitDebugStr(); 614 615 if (useSplitDwarf()) 616 emitDebugLocDWO(); 617 else 618 // Emit info into a debug loc section. 619 emitDebugLoc(); 620 621 // Corresponding abbreviations into a abbrev section. 622 emitAbbreviations(); 623 624 // Emit all the DIEs into a debug info section. 625 emitDebugInfo(); 626 627 // Emit info into a debug aranges section. 628 if (GenerateARangeSection) 629 emitDebugARanges(); 630 631 // Emit info into a debug ranges section. 632 emitDebugRanges(); 633 634 if (useSplitDwarf()) { 635 emitDebugStrDWO(); 636 emitDebugInfoDWO(); 637 emitDebugAbbrevDWO(); 638 emitDebugLineDWO(); 639 // Emit DWO addresses. 640 AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection()); 641 } 642 643 // Emit info into the dwarf accelerator table sections. 644 if (useDwarfAccelTables()) { 645 emitAccelNames(); 646 emitAccelObjC(); 647 emitAccelNamespaces(); 648 emitAccelTypes(); 649 } 650 651 // Emit the pubnames and pubtypes sections if requested. 652 if (HasDwarfPubSections) { 653 emitDebugPubNames(GenerateGnuPubSections); 654 emitDebugPubTypes(GenerateGnuPubSections); 655 } 656 657 // clean up. 658 SPMap.clear(); 659 AbstractVariables.clear(); 660} 661 662// Find abstract variable, if any, associated with Var. 663DbgVariable * 664DwarfDebug::getExistingAbstractVariable(InlinedVariable IV, 665 const DILocalVariable *&Cleansed) { 666 // More then one inlined variable corresponds to one abstract variable. 667 Cleansed = IV.first; 668 auto I = AbstractVariables.find(Cleansed); 669 if (I != AbstractVariables.end()) 670 return I->second.get(); 671 return nullptr; 672} 673 674DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV) { 675 const DILocalVariable *Cleansed; 676 return getExistingAbstractVariable(IV, Cleansed); 677} 678 679void DwarfDebug::createAbstractVariable(const DILocalVariable *Var, 680 LexicalScope *Scope) { 681 auto AbsDbgVariable = make_unique<DbgVariable>(Var, /* IA */ nullptr, this); 682 InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get()); 683 AbstractVariables[Var] = std::move(AbsDbgVariable); 684} 685 686void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV, 687 const MDNode *ScopeNode) { 688 const DILocalVariable *Cleansed = nullptr; 689 if (getExistingAbstractVariable(IV, Cleansed)) 690 return; 691 692 createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope( 693 cast<DILocalScope>(ScopeNode))); 694} 695 696void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped( 697 InlinedVariable IV, const MDNode *ScopeNode) { 698 const DILocalVariable *Cleansed = nullptr; 699 if (getExistingAbstractVariable(IV, Cleansed)) 700 return; 701 702 if (LexicalScope *Scope = 703 LScopes.findAbstractScope(cast_or_null<DILocalScope>(ScopeNode))) 704 createAbstractVariable(Cleansed, Scope); 705} 706 707// Collect variable information from side table maintained by MMI. 708void DwarfDebug::collectVariableInfoFromMMITable( 709 DenseSet<InlinedVariable> &Processed) { 710 for (const auto &VI : MMI->getVariableDbgInfo()) { 711 if (!VI.Var) 712 continue; 713 assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) && 714 "Expected inlined-at fields to agree"); 715 716 InlinedVariable Var(VI.Var, VI.Loc->getInlinedAt()); 717 Processed.insert(Var); 718 LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc); 719 720 // If variable scope is not found then skip this variable. 721 if (!Scope) 722 continue; 723 724 ensureAbstractVariableIsCreatedIfScoped(Var, Scope->getScopeNode()); 725 auto RegVar = make_unique<DbgVariable>(Var.first, Var.second, this); 726 RegVar->initializeMMI(VI.Expr, VI.Slot); 727 if (InfoHolder.addScopeVariable(Scope, RegVar.get())) 728 ConcreteVariables.push_back(std::move(RegVar)); 729 } 730} 731 732// Get .debug_loc entry for the instruction range starting at MI. 733static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) { 734 const DIExpression *Expr = MI->getDebugExpression(); 735 736 assert(MI->getNumOperands() == 4); 737 if (MI->getOperand(0).isReg()) { 738 MachineLocation MLoc; 739 // If the second operand is an immediate, this is a 740 // register-indirect address. 741 if (!MI->getOperand(1).isImm()) 742 MLoc.set(MI->getOperand(0).getReg()); 743 else 744 MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm()); 745 return DebugLocEntry::Value(Expr, MLoc); 746 } 747 if (MI->getOperand(0).isImm()) 748 return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm()); 749 if (MI->getOperand(0).isFPImm()) 750 return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm()); 751 if (MI->getOperand(0).isCImm()) 752 return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm()); 753 754 llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!"); 755} 756 757/// Determine whether two variable pieces overlap. 758static bool piecesOverlap(const DIExpression *P1, const DIExpression *P2) { 759 if (!P1->isBitPiece() || !P2->isBitPiece()) 760 return true; 761 unsigned l1 = P1->getBitPieceOffset(); 762 unsigned l2 = P2->getBitPieceOffset(); 763 unsigned r1 = l1 + P1->getBitPieceSize(); 764 unsigned r2 = l2 + P2->getBitPieceSize(); 765 // True where [l1,r1[ and [r1,r2[ overlap. 766 return (l1 < r2) && (l2 < r1); 767} 768 769/// Build the location list for all DBG_VALUEs in the function that 770/// describe the same variable. If the ranges of several independent 771/// pieces of the same variable overlap partially, split them up and 772/// combine the ranges. The resulting DebugLocEntries are will have 773/// strict monotonically increasing begin addresses and will never 774/// overlap. 775// 776// Input: 777// 778// Ranges History [var, loc, piece ofs size] 779// 0 | [x, (reg0, piece 0, 32)] 780// 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry 781// 2 | | ... 782// 3 | [clobber reg0] 783// 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of 784// x. 785// 786// Output: 787// 788// [0-1] [x, (reg0, piece 0, 32)] 789// [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)] 790// [3-4] [x, (reg1, piece 32, 32)] 791// [4- ] [x, (mem, piece 0, 64)] 792void 793DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc, 794 const DbgValueHistoryMap::InstrRanges &Ranges) { 795 SmallVector<DebugLocEntry::Value, 4> OpenRanges; 796 797 for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) { 798 const MachineInstr *Begin = I->first; 799 const MachineInstr *End = I->second; 800 assert(Begin->isDebugValue() && "Invalid History entry"); 801 802 // Check if a variable is inaccessible in this range. 803 if (Begin->getNumOperands() > 1 && 804 Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) { 805 OpenRanges.clear(); 806 continue; 807 } 808 809 // If this piece overlaps with any open ranges, truncate them. 810 const DIExpression *DIExpr = Begin->getDebugExpression(); 811 auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(), 812 [&](DebugLocEntry::Value R) { 813 return piecesOverlap(DIExpr, R.getExpression()); 814 }); 815 OpenRanges.erase(Last, OpenRanges.end()); 816 817 const MCSymbol *StartLabel = getLabelBeforeInsn(Begin); 818 assert(StartLabel && "Forgot label before DBG_VALUE starting a range!"); 819 820 const MCSymbol *EndLabel; 821 if (End != nullptr) 822 EndLabel = getLabelAfterInsn(End); 823 else if (std::next(I) == Ranges.end()) 824 EndLabel = Asm->getFunctionEnd(); 825 else 826 EndLabel = getLabelBeforeInsn(std::next(I)->first); 827 assert(EndLabel && "Forgot label after instruction ending a range!"); 828 829 DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n"); 830 831 auto Value = getDebugLocValue(Begin); 832 DebugLocEntry Loc(StartLabel, EndLabel, Value); 833 bool couldMerge = false; 834 835 // If this is a piece, it may belong to the current DebugLocEntry. 836 if (DIExpr->isBitPiece()) { 837 // Add this value to the list of open ranges. 838 OpenRanges.push_back(Value); 839 840 // Attempt to add the piece to the last entry. 841 if (!DebugLoc.empty()) 842 if (DebugLoc.back().MergeValues(Loc)) 843 couldMerge = true; 844 } 845 846 if (!couldMerge) { 847 // Need to add a new DebugLocEntry. Add all values from still 848 // valid non-overlapping pieces. 849 if (OpenRanges.size()) 850 Loc.addValues(OpenRanges); 851 852 DebugLoc.push_back(std::move(Loc)); 853 } 854 855 // Attempt to coalesce the ranges of two otherwise identical 856 // DebugLocEntries. 857 auto CurEntry = DebugLoc.rbegin(); 858 DEBUG({ 859 dbgs() << CurEntry->getValues().size() << " Values:\n"; 860 for (auto &Value : CurEntry->getValues()) 861 Value.getExpression()->dump(); 862 dbgs() << "-----\n"; 863 }); 864 865 auto PrevEntry = std::next(CurEntry); 866 if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry)) 867 DebugLoc.pop_back(); 868 } 869} 870 871DbgVariable *DwarfDebug::createConcreteVariable(LexicalScope &Scope, 872 InlinedVariable IV) { 873 ensureAbstractVariableIsCreatedIfScoped(IV, Scope.getScopeNode()); 874 ConcreteVariables.push_back( 875 make_unique<DbgVariable>(IV.first, IV.second, this)); 876 InfoHolder.addScopeVariable(&Scope, ConcreteVariables.back().get()); 877 return ConcreteVariables.back().get(); 878} 879 880// Find variables for each lexical scope. 881void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, 882 const DISubprogram *SP, 883 DenseSet<InlinedVariable> &Processed) { 884 // Grab the variable info that was squirreled away in the MMI side-table. 885 collectVariableInfoFromMMITable(Processed); 886 887 for (const auto &I : DbgValues) { 888 InlinedVariable IV = I.first; 889 if (Processed.count(IV)) 890 continue; 891 892 // Instruction ranges, specifying where IV is accessible. 893 const auto &Ranges = I.second; 894 if (Ranges.empty()) 895 continue; 896 897 LexicalScope *Scope = nullptr; 898 if (const DILocation *IA = IV.second) 899 Scope = LScopes.findInlinedScope(IV.first->getScope(), IA); 900 else 901 Scope = LScopes.findLexicalScope(IV.first->getScope()); 902 // If variable scope is not found then skip this variable. 903 if (!Scope) 904 continue; 905 906 Processed.insert(IV); 907 DbgVariable *RegVar = createConcreteVariable(*Scope, IV); 908 909 const MachineInstr *MInsn = Ranges.front().first; 910 assert(MInsn->isDebugValue() && "History must begin with debug value"); 911 912 // Check if the first DBG_VALUE is valid for the rest of the function. 913 if (Ranges.size() == 1 && Ranges.front().second == nullptr) { 914 RegVar->initializeDbgValue(MInsn); 915 continue; 916 } 917 918 // Handle multiple DBG_VALUE instructions describing one variable. 919 DebugLocStream::ListBuilder List(DebugLocs, TheCU, *Asm, *RegVar, *MInsn); 920 921 // Build the location list for this variable. 922 SmallVector<DebugLocEntry, 8> Entries; 923 buildLocationList(Entries, Ranges); 924 925 // If the variable has an DIBasicType, extract it. Basic types cannot have 926 // unique identifiers, so don't bother resolving the type with the 927 // identifier map. 928 const DIBasicType *BT = dyn_cast<DIBasicType>( 929 static_cast<const Metadata *>(IV.first->getType())); 930 931 // Finalize the entry by lowering it into a DWARF bytestream. 932 for (auto &Entry : Entries) 933 Entry.finalize(*Asm, List, BT); 934 } 935 936 // Collect info for variables that were optimized out. 937 for (const DILocalVariable *DV : SP->getVariables()) { 938 if (Processed.insert(InlinedVariable(DV, nullptr)).second) 939 if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) 940 createConcreteVariable(*Scope, InlinedVariable(DV, nullptr)); 941 } 942} 943 944// Return Label preceding the instruction. 945MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) { 946 MCSymbol *Label = LabelsBeforeInsn.lookup(MI); 947 assert(Label && "Didn't insert label before instruction"); 948 return Label; 949} 950 951// Return Label immediately following the instruction. 952MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) { 953 return LabelsAfterInsn.lookup(MI); 954} 955 956// Process beginning of an instruction. 957void DwarfDebug::beginInstruction(const MachineInstr *MI) { 958 assert(CurMI == nullptr); 959 CurMI = MI; 960 // Check if source location changes, but ignore DBG_VALUE locations. 961 if (!MI->isDebugValue()) { 962 DebugLoc DL = MI->getDebugLoc(); 963 if (DL != PrevInstLoc) { 964 if (DL) { 965 unsigned Flags = 0; 966 PrevInstLoc = DL; 967 if (DL == PrologEndLoc) { 968 Flags |= DWARF2_FLAG_PROLOGUE_END; 969 PrologEndLoc = DebugLoc(); 970 Flags |= DWARF2_FLAG_IS_STMT; 971 } 972 if (DL.getLine() != 973 Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine()) 974 Flags |= DWARF2_FLAG_IS_STMT; 975 976 const MDNode *Scope = DL.getScope(); 977 recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags); 978 } else if (UnknownLocations) { 979 PrevInstLoc = DL; 980 recordSourceLine(0, 0, nullptr, 0); 981 } 982 } 983 } 984 985 // Insert labels where requested. 986 DenseMap<const MachineInstr *, MCSymbol *>::iterator I = 987 LabelsBeforeInsn.find(MI); 988 989 // No label needed. 990 if (I == LabelsBeforeInsn.end()) 991 return; 992 993 // Label already assigned. 994 if (I->second) 995 return; 996 997 if (!PrevLabel) { 998 PrevLabel = MMI->getContext().createTempSymbol(); 999 Asm->OutStreamer->EmitLabel(PrevLabel); 1000 } 1001 I->second = PrevLabel; 1002} 1003 1004// Process end of an instruction. 1005void DwarfDebug::endInstruction() { 1006 assert(CurMI != nullptr); 1007 // Don't create a new label after DBG_VALUE instructions. 1008 // They don't generate code. 1009 if (!CurMI->isDebugValue()) 1010 PrevLabel = nullptr; 1011 1012 DenseMap<const MachineInstr *, MCSymbol *>::iterator I = 1013 LabelsAfterInsn.find(CurMI); 1014 CurMI = nullptr; 1015 1016 // No label needed. 1017 if (I == LabelsAfterInsn.end()) 1018 return; 1019 1020 // Label already assigned. 1021 if (I->second) 1022 return; 1023 1024 // We need a label after this instruction. 1025 if (!PrevLabel) { 1026 PrevLabel = MMI->getContext().createTempSymbol(); 1027 Asm->OutStreamer->EmitLabel(PrevLabel); 1028 } 1029 I->second = PrevLabel; 1030} 1031 1032// Each LexicalScope has first instruction and last instruction to mark 1033// beginning and end of a scope respectively. Create an inverse map that list 1034// scopes starts (and ends) with an instruction. One instruction may start (or 1035// end) multiple scopes. Ignore scopes that are not reachable. 1036void DwarfDebug::identifyScopeMarkers() { 1037 SmallVector<LexicalScope *, 4> WorkList; 1038 WorkList.push_back(LScopes.getCurrentFunctionScope()); 1039 while (!WorkList.empty()) { 1040 LexicalScope *S = WorkList.pop_back_val(); 1041 1042 const SmallVectorImpl<LexicalScope *> &Children = S->getChildren(); 1043 if (!Children.empty()) 1044 WorkList.append(Children.begin(), Children.end()); 1045 1046 if (S->isAbstractScope()) 1047 continue; 1048 1049 for (const InsnRange &R : S->getRanges()) { 1050 assert(R.first && "InsnRange does not have first instruction!"); 1051 assert(R.second && "InsnRange does not have second instruction!"); 1052 requestLabelBeforeInsn(R.first); 1053 requestLabelAfterInsn(R.second); 1054 } 1055 } 1056} 1057 1058static DebugLoc findPrologueEndLoc(const MachineFunction *MF) { 1059 // First known non-DBG_VALUE and non-frame setup location marks 1060 // the beginning of the function body. 1061 for (const auto &MBB : *MF) 1062 for (const auto &MI : MBB) 1063 if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) && 1064 MI.getDebugLoc()) { 1065 // Did the target forget to set the FrameSetup flag for CFI insns? 1066 assert(!MI.isCFIInstruction() && 1067 "First non-frame-setup instruction is a CFI instruction."); 1068 return MI.getDebugLoc(); 1069 } 1070 return DebugLoc(); 1071} 1072 1073// Gather pre-function debug information. Assumes being called immediately 1074// after the function entry point has been emitted. 1075void DwarfDebug::beginFunction(const MachineFunction *MF) { 1076 CurFn = MF; 1077 1078 // If there's no debug info for the function we're not going to do anything. 1079 if (!MMI->hasDebugInfo()) 1080 return; 1081 1082 auto DI = FunctionDIs.find(MF->getFunction()); 1083 if (DI == FunctionDIs.end()) 1084 return; 1085 1086 // Grab the lexical scopes for the function, if we don't have any of those 1087 // then we're not going to be able to do anything. 1088 LScopes.initialize(*MF); 1089 if (LScopes.empty()) 1090 return; 1091 1092 assert(DbgValues.empty() && "DbgValues map wasn't cleaned!"); 1093 1094 // Make sure that each lexical scope will have a begin/end label. 1095 identifyScopeMarkers(); 1096 1097 // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function 1098 // belongs to so that we add to the correct per-cu line table in the 1099 // non-asm case. 1100 LexicalScope *FnScope = LScopes.getCurrentFunctionScope(); 1101 // FnScope->getScopeNode() and DI->second should represent the same function, 1102 // though they may not be the same MDNode due to inline functions merged in 1103 // LTO where the debug info metadata still differs (either due to distinct 1104 // written differences - two versions of a linkonce_odr function 1105 // written/copied into two separate files, or some sub-optimal metadata that 1106 // isn't structurally identical (see: file path/name info from clang, which 1107 // includes the directory of the cpp file being built, even when the file name 1108 // is absolute (such as an <> lookup header))) 1109 DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode()); 1110 assert(TheCU && "Unable to find compile unit!"); 1111 if (Asm->OutStreamer->hasRawTextSupport()) 1112 // Use a single line table if we are generating assembly. 1113 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0); 1114 else 1115 Asm->OutStreamer->getContext().setDwarfCompileUnitID(TheCU->getUniqueID()); 1116 1117 // Calculate history for local variables. 1118 calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(), 1119 DbgValues); 1120 1121 // Request labels for the full history. 1122 for (const auto &I : DbgValues) { 1123 const auto &Ranges = I.second; 1124 if (Ranges.empty()) 1125 continue; 1126 1127 // The first mention of a function argument gets the CurrentFnBegin 1128 // label, so arguments are visible when breaking at function entry. 1129 const DILocalVariable *DIVar = Ranges.front().first->getDebugVariable(); 1130 if (DIVar->getTag() == dwarf::DW_TAG_arg_variable && 1131 getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) { 1132 LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin(); 1133 if (Ranges.front().first->getDebugExpression()->isBitPiece()) { 1134 // Mark all non-overlapping initial pieces. 1135 for (auto I = Ranges.begin(); I != Ranges.end(); ++I) { 1136 const DIExpression *Piece = I->first->getDebugExpression(); 1137 if (std::all_of(Ranges.begin(), I, 1138 [&](DbgValueHistoryMap::InstrRange Pred) { 1139 return !piecesOverlap(Piece, Pred.first->getDebugExpression()); 1140 })) 1141 LabelsBeforeInsn[I->first] = Asm->getFunctionBegin(); 1142 else 1143 break; 1144 } 1145 } 1146 } 1147 1148 for (const auto &Range : Ranges) { 1149 requestLabelBeforeInsn(Range.first); 1150 if (Range.second) 1151 requestLabelAfterInsn(Range.second); 1152 } 1153 } 1154 1155 PrevInstLoc = DebugLoc(); 1156 PrevLabel = Asm->getFunctionBegin(); 1157 1158 // Record beginning of function. 1159 PrologEndLoc = findPrologueEndLoc(MF); 1160 if (DILocation *L = PrologEndLoc) { 1161 // We'd like to list the prologue as "not statements" but GDB behaves 1162 // poorly if we do that. Revisit this with caution/GDB (7.5+) testing. 1163 auto *SP = L->getInlinedAtScope()->getSubprogram(); 1164 recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT); 1165 } 1166} 1167 1168// Gather and emit post-function debug information. 1169void DwarfDebug::endFunction(const MachineFunction *MF) { 1170 assert(CurFn == MF && 1171 "endFunction should be called with the same function as beginFunction"); 1172 1173 if (!MMI->hasDebugInfo() || LScopes.empty() || 1174 !FunctionDIs.count(MF->getFunction())) { 1175 // If we don't have a lexical scope for this function then there will 1176 // be a hole in the range information. Keep note of this by setting the 1177 // previously used section to nullptr. 1178 PrevCU = nullptr; 1179 CurFn = nullptr; 1180 return; 1181 } 1182 1183 // Set DwarfDwarfCompileUnitID in MCContext to default value. 1184 Asm->OutStreamer->getContext().setDwarfCompileUnitID(0); 1185 1186 LexicalScope *FnScope = LScopes.getCurrentFunctionScope(); 1187 auto *SP = cast<DISubprogram>(FnScope->getScopeNode()); 1188 DwarfCompileUnit &TheCU = *SPMap.lookup(SP); 1189 1190 DenseSet<InlinedVariable> ProcessedVars; 1191 collectVariableInfo(TheCU, SP, ProcessedVars); 1192 1193 // Add the range of this function to the list of ranges for the CU. 1194 TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd())); 1195 1196 // Under -gmlt, skip building the subprogram if there are no inlined 1197 // subroutines inside it. 1198 if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly && 1199 LScopes.getAbstractScopesList().empty() && !IsDarwin) { 1200 assert(InfoHolder.getScopeVariables().empty()); 1201 assert(DbgValues.empty()); 1202 // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed 1203 // by a -gmlt CU. Add a test and remove this assertion. 1204 assert(AbstractVariables.empty()); 1205 LabelsBeforeInsn.clear(); 1206 LabelsAfterInsn.clear(); 1207 PrevLabel = nullptr; 1208 CurFn = nullptr; 1209 return; 1210 } 1211 1212#ifndef NDEBUG 1213 size_t NumAbstractScopes = LScopes.getAbstractScopesList().size(); 1214#endif 1215 // Construct abstract scopes. 1216 for (LexicalScope *AScope : LScopes.getAbstractScopesList()) { 1217 auto *SP = cast<DISubprogram>(AScope->getScopeNode()); 1218 // Collect info for variables that were optimized out. 1219 for (const DILocalVariable *DV : SP->getVariables()) { 1220 if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second) 1221 continue; 1222 ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr), 1223 DV->getScope()); 1224 assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes 1225 && "ensureAbstractVariableIsCreated inserted abstract scopes"); 1226 } 1227 constructAbstractSubprogramScopeDIE(AScope); 1228 } 1229 1230 TheCU.constructSubprogramScopeDIE(FnScope); 1231 if (auto *SkelCU = TheCU.getSkeleton()) 1232 if (!LScopes.getAbstractScopesList().empty()) 1233 SkelCU->constructSubprogramScopeDIE(FnScope); 1234 1235 // Clear debug info 1236 // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the 1237 // DbgVariables except those that are also in AbstractVariables (since they 1238 // can be used cross-function) 1239 InfoHolder.getScopeVariables().clear(); 1240 DbgValues.clear(); 1241 LabelsBeforeInsn.clear(); 1242 LabelsAfterInsn.clear(); 1243 PrevLabel = nullptr; 1244 CurFn = nullptr; 1245} 1246 1247// Register a source line with debug info. Returns the unique label that was 1248// emitted and which provides correspondence to the source line list. 1249void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S, 1250 unsigned Flags) { 1251 StringRef Fn; 1252 StringRef Dir; 1253 unsigned Src = 1; 1254 unsigned Discriminator = 0; 1255 if (auto *Scope = cast_or_null<DIScope>(S)) { 1256 Fn = Scope->getFilename(); 1257 Dir = Scope->getDirectory(); 1258 if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope)) 1259 Discriminator = LBF->getDiscriminator(); 1260 1261 unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID(); 1262 Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID]) 1263 .getOrCreateSourceID(Fn, Dir); 1264 } 1265 Asm->OutStreamer->EmitDwarfLocDirective(Src, Line, Col, Flags, 0, 1266 Discriminator, Fn); 1267} 1268 1269//===----------------------------------------------------------------------===// 1270// Emit Methods 1271//===----------------------------------------------------------------------===// 1272 1273// Emit the debug info section. 1274void DwarfDebug::emitDebugInfo() { 1275 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; 1276 Holder.emitUnits(/* UseOffsets */ false); 1277} 1278 1279// Emit the abbreviation section. 1280void DwarfDebug::emitAbbreviations() { 1281 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; 1282 1283 Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection()); 1284} 1285 1286void DwarfDebug::emitAccel(DwarfAccelTable &Accel, MCSection *Section, 1287 StringRef TableName) { 1288 Accel.FinalizeTable(Asm, TableName); 1289 Asm->OutStreamer->SwitchSection(Section); 1290 1291 // Emit the full data. 1292 Accel.emit(Asm, Section->getBeginSymbol(), this); 1293} 1294 1295// Emit visible names into a hashed accelerator table section. 1296void DwarfDebug::emitAccelNames() { 1297 emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(), 1298 "Names"); 1299} 1300 1301// Emit objective C classes and categories into a hashed accelerator table 1302// section. 1303void DwarfDebug::emitAccelObjC() { 1304 emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(), 1305 "ObjC"); 1306} 1307 1308// Emit namespace dies into a hashed accelerator table. 1309void DwarfDebug::emitAccelNamespaces() { 1310 emitAccel(AccelNamespace, 1311 Asm->getObjFileLowering().getDwarfAccelNamespaceSection(), 1312 "namespac"); 1313} 1314 1315// Emit type dies into a hashed accelerator table. 1316void DwarfDebug::emitAccelTypes() { 1317 emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(), 1318 "types"); 1319} 1320 1321// Public name handling. 1322// The format for the various pubnames: 1323// 1324// dwarf pubnames - offset/name pairs where the offset is the offset into the CU 1325// for the DIE that is named. 1326// 1327// gnu pubnames - offset/index value/name tuples where the offset is the offset 1328// into the CU and the index value is computed according to the type of value 1329// for the DIE that is named. 1330// 1331// For type units the offset is the offset of the skeleton DIE. For split dwarf 1332// it's the offset within the debug_info/debug_types dwo section, however, the 1333// reference in the pubname header doesn't change. 1334 1335/// computeIndexValue - Compute the gdb index value for the DIE and CU. 1336static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU, 1337 const DIE *Die) { 1338 dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC; 1339 1340 // We could have a specification DIE that has our most of our knowledge, 1341 // look for that now. 1342 if (DIEValue SpecVal = Die->findAttribute(dwarf::DW_AT_specification)) { 1343 DIE &SpecDIE = SpecVal.getDIEEntry().getEntry(); 1344 if (SpecDIE.findAttribute(dwarf::DW_AT_external)) 1345 Linkage = dwarf::GIEL_EXTERNAL; 1346 } else if (Die->findAttribute(dwarf::DW_AT_external)) 1347 Linkage = dwarf::GIEL_EXTERNAL; 1348 1349 switch (Die->getTag()) { 1350 case dwarf::DW_TAG_class_type: 1351 case dwarf::DW_TAG_structure_type: 1352 case dwarf::DW_TAG_union_type: 1353 case dwarf::DW_TAG_enumeration_type: 1354 return dwarf::PubIndexEntryDescriptor( 1355 dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus 1356 ? dwarf::GIEL_STATIC 1357 : dwarf::GIEL_EXTERNAL); 1358 case dwarf::DW_TAG_typedef: 1359 case dwarf::DW_TAG_base_type: 1360 case dwarf::DW_TAG_subrange_type: 1361 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC); 1362 case dwarf::DW_TAG_namespace: 1363 return dwarf::GIEK_TYPE; 1364 case dwarf::DW_TAG_subprogram: 1365 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage); 1366 case dwarf::DW_TAG_variable: 1367 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage); 1368 case dwarf::DW_TAG_enumerator: 1369 return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, 1370 dwarf::GIEL_STATIC); 1371 default: 1372 return dwarf::GIEK_NONE; 1373 } 1374} 1375 1376/// emitDebugPubNames - Emit visible names into a debug pubnames section. 1377/// 1378void DwarfDebug::emitDebugPubNames(bool GnuStyle) { 1379 MCSection *PSec = GnuStyle 1380 ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection() 1381 : Asm->getObjFileLowering().getDwarfPubNamesSection(); 1382 1383 emitDebugPubSection(GnuStyle, PSec, "Names", 1384 &DwarfCompileUnit::getGlobalNames); 1385} 1386 1387void DwarfDebug::emitDebugPubSection( 1388 bool GnuStyle, MCSection *PSec, StringRef Name, 1389 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) { 1390 for (const auto &NU : CUMap) { 1391 DwarfCompileUnit *TheU = NU.second; 1392 1393 const auto &Globals = (TheU->*Accessor)(); 1394 1395 if (Globals.empty()) 1396 continue; 1397 1398 if (auto *Skeleton = TheU->getSkeleton()) 1399 TheU = Skeleton; 1400 1401 // Start the dwarf pubnames section. 1402 Asm->OutStreamer->SwitchSection(PSec); 1403 1404 // Emit the header. 1405 Asm->OutStreamer->AddComment("Length of Public " + Name + " Info"); 1406 MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin"); 1407 MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end"); 1408 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); 1409 1410 Asm->OutStreamer->EmitLabel(BeginLabel); 1411 1412 Asm->OutStreamer->AddComment("DWARF Version"); 1413 Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION); 1414 1415 Asm->OutStreamer->AddComment("Offset of Compilation Unit Info"); 1416 Asm->emitDwarfSymbolReference(TheU->getLabelBegin()); 1417 1418 Asm->OutStreamer->AddComment("Compilation Unit Length"); 1419 Asm->EmitInt32(TheU->getLength()); 1420 1421 // Emit the pubnames for this compilation unit. 1422 for (const auto &GI : Globals) { 1423 const char *Name = GI.getKeyData(); 1424 const DIE *Entity = GI.second; 1425 1426 Asm->OutStreamer->AddComment("DIE offset"); 1427 Asm->EmitInt32(Entity->getOffset()); 1428 1429 if (GnuStyle) { 1430 dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity); 1431 Asm->OutStreamer->AddComment( 1432 Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " + 1433 dwarf::GDBIndexEntryLinkageString(Desc.Linkage)); 1434 Asm->EmitInt8(Desc.toBits()); 1435 } 1436 1437 Asm->OutStreamer->AddComment("External Name"); 1438 Asm->OutStreamer->EmitBytes(StringRef(Name, GI.getKeyLength() + 1)); 1439 } 1440 1441 Asm->OutStreamer->AddComment("End Mark"); 1442 Asm->EmitInt32(0); 1443 Asm->OutStreamer->EmitLabel(EndLabel); 1444 } 1445} 1446 1447void DwarfDebug::emitDebugPubTypes(bool GnuStyle) { 1448 MCSection *PSec = GnuStyle 1449 ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection() 1450 : Asm->getObjFileLowering().getDwarfPubTypesSection(); 1451 1452 emitDebugPubSection(GnuStyle, PSec, "Types", 1453 &DwarfCompileUnit::getGlobalTypes); 1454} 1455 1456// Emit visible names into a debug str section. 1457void DwarfDebug::emitDebugStr() { 1458 DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; 1459 Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection()); 1460} 1461 1462void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer, 1463 const DebugLocStream::Entry &Entry) { 1464 auto &&Comments = DebugLocs.getComments(Entry); 1465 auto Comment = Comments.begin(); 1466 auto End = Comments.end(); 1467 for (uint8_t Byte : DebugLocs.getBytes(Entry)) 1468 Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : ""); 1469} 1470 1471static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT, 1472 ByteStreamer &Streamer, 1473 const DebugLocEntry::Value &Value, 1474 unsigned PieceOffsetInBits) { 1475 DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(), 1476 AP.getDwarfDebug()->getDwarfVersion(), 1477 Streamer); 1478 // Regular entry. 1479 if (Value.isInt()) { 1480 if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed || 1481 BT->getEncoding() == dwarf::DW_ATE_signed_char)) 1482 DwarfExpr.AddSignedConstant(Value.getInt()); 1483 else 1484 DwarfExpr.AddUnsignedConstant(Value.getInt()); 1485 } else if (Value.isLocation()) { 1486 MachineLocation Loc = Value.getLoc(); 1487 const DIExpression *Expr = Value.getExpression(); 1488 if (!Expr || !Expr->getNumElements()) 1489 // Regular entry. 1490 AP.EmitDwarfRegOp(Streamer, Loc); 1491 else { 1492 // Complex address entry. 1493 if (Loc.getOffset()) { 1494 DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset()); 1495 DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(), 1496 PieceOffsetInBits); 1497 } else 1498 DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(), 1499 PieceOffsetInBits); 1500 } 1501 } 1502 // else ... ignore constant fp. There is not any good way to 1503 // to represent them here in dwarf. 1504 // FIXME: ^ 1505} 1506 1507void DebugLocEntry::finalize(const AsmPrinter &AP, 1508 DebugLocStream::ListBuilder &List, 1509 const DIBasicType *BT) { 1510 DebugLocStream::EntryBuilder Entry(List, Begin, End); 1511 BufferByteStreamer Streamer = Entry.getStreamer(); 1512 const DebugLocEntry::Value &Value = Values[0]; 1513 if (Value.isBitPiece()) { 1514 // Emit all pieces that belong to the same variable and range. 1515 assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) { 1516 return P.isBitPiece(); 1517 }) && "all values are expected to be pieces"); 1518 assert(std::is_sorted(Values.begin(), Values.end()) && 1519 "pieces are expected to be sorted"); 1520 1521 unsigned Offset = 0; 1522 for (auto Piece : Values) { 1523 const DIExpression *Expr = Piece.getExpression(); 1524 unsigned PieceOffset = Expr->getBitPieceOffset(); 1525 unsigned PieceSize = Expr->getBitPieceSize(); 1526 assert(Offset <= PieceOffset && "overlapping or duplicate pieces"); 1527 if (Offset < PieceOffset) { 1528 // The DWARF spec seriously mandates pieces with no locations for gaps. 1529 DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(), 1530 AP.getDwarfDebug()->getDwarfVersion(), 1531 Streamer); 1532 Expr.AddOpPiece(PieceOffset-Offset, 0); 1533 Offset += PieceOffset-Offset; 1534 } 1535 Offset += PieceSize; 1536 1537 emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset); 1538 } 1539 } else { 1540 assert(Values.size() == 1 && "only pieces may have >1 value"); 1541 emitDebugLocValue(AP, BT, Streamer, Value, 0); 1542 } 1543} 1544 1545void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) { 1546 // Emit the size. 1547 Asm->OutStreamer->AddComment("Loc expr size"); 1548 Asm->EmitInt16(DebugLocs.getBytes(Entry).size()); 1549 1550 // Emit the entry. 1551 APByteStreamer Streamer(*Asm); 1552 emitDebugLocEntry(Streamer, Entry); 1553} 1554 1555// Emit locations into the debug loc section. 1556void DwarfDebug::emitDebugLoc() { 1557 // Start the dwarf loc section. 1558 Asm->OutStreamer->SwitchSection( 1559 Asm->getObjFileLowering().getDwarfLocSection()); 1560 unsigned char Size = Asm->getDataLayout().getPointerSize(); 1561 for (const auto &List : DebugLocs.getLists()) { 1562 Asm->OutStreamer->EmitLabel(List.Label); 1563 const DwarfCompileUnit *CU = List.CU; 1564 for (const auto &Entry : DebugLocs.getEntries(List)) { 1565 // Set up the range. This range is relative to the entry point of the 1566 // compile unit. This is a hard coded 0 for low_pc when we're emitting 1567 // ranges, or the DW_AT_low_pc on the compile unit otherwise. 1568 if (auto *Base = CU->getBaseAddress()) { 1569 Asm->EmitLabelDifference(Entry.BeginSym, Base, Size); 1570 Asm->EmitLabelDifference(Entry.EndSym, Base, Size); 1571 } else { 1572 Asm->OutStreamer->EmitSymbolValue(Entry.BeginSym, Size); 1573 Asm->OutStreamer->EmitSymbolValue(Entry.EndSym, Size); 1574 } 1575 1576 emitDebugLocEntryLocation(Entry); 1577 } 1578 Asm->OutStreamer->EmitIntValue(0, Size); 1579 Asm->OutStreamer->EmitIntValue(0, Size); 1580 } 1581} 1582 1583void DwarfDebug::emitDebugLocDWO() { 1584 Asm->OutStreamer->SwitchSection( 1585 Asm->getObjFileLowering().getDwarfLocDWOSection()); 1586 for (const auto &List : DebugLocs.getLists()) { 1587 Asm->OutStreamer->EmitLabel(List.Label); 1588 for (const auto &Entry : DebugLocs.getEntries(List)) { 1589 // Just always use start_length for now - at least that's one address 1590 // rather than two. We could get fancier and try to, say, reuse an 1591 // address we know we've emitted elsewhere (the start of the function? 1592 // The start of the CU or CU subrange that encloses this range?) 1593 Asm->EmitInt8(dwarf::DW_LLE_start_length_entry); 1594 unsigned idx = AddrPool.getIndex(Entry.BeginSym); 1595 Asm->EmitULEB128(idx); 1596 Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4); 1597 1598 emitDebugLocEntryLocation(Entry); 1599 } 1600 Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry); 1601 } 1602} 1603 1604struct ArangeSpan { 1605 const MCSymbol *Start, *End; 1606}; 1607 1608// Emit a debug aranges section, containing a CU lookup for any 1609// address we can tie back to a CU. 1610void DwarfDebug::emitDebugARanges() { 1611 // Provides a unique id per text section. 1612 MapVector<MCSection *, SmallVector<SymbolCU, 8>> SectionMap; 1613 1614 // Filter labels by section. 1615 for (const SymbolCU &SCU : ArangeLabels) { 1616 if (SCU.Sym->isInSection()) { 1617 // Make a note of this symbol and it's section. 1618 MCSection *Section = &SCU.Sym->getSection(); 1619 if (!Section->getKind().isMetadata()) 1620 SectionMap[Section].push_back(SCU); 1621 } else { 1622 // Some symbols (e.g. common/bss on mach-o) can have no section but still 1623 // appear in the output. This sucks as we rely on sections to build 1624 // arange spans. We can do it without, but it's icky. 1625 SectionMap[nullptr].push_back(SCU); 1626 } 1627 } 1628 1629 // Add terminating symbols for each section. 1630 for (const auto &I : SectionMap) { 1631 MCSection *Section = I.first; 1632 MCSymbol *Sym = nullptr; 1633 1634 if (Section) 1635 Sym = Asm->OutStreamer->endSection(Section); 1636 1637 // Insert a final terminator. 1638 SectionMap[Section].push_back(SymbolCU(nullptr, Sym)); 1639 } 1640 1641 DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans; 1642 1643 for (auto &I : SectionMap) { 1644 const MCSection *Section = I.first; 1645 SmallVector<SymbolCU, 8> &List = I.second; 1646 if (List.size() < 2) 1647 continue; 1648 1649 // If we have no section (e.g. common), just write out 1650 // individual spans for each symbol. 1651 if (!Section) { 1652 for (const SymbolCU &Cur : List) { 1653 ArangeSpan Span; 1654 Span.Start = Cur.Sym; 1655 Span.End = nullptr; 1656 if (Cur.CU) 1657 Spans[Cur.CU].push_back(Span); 1658 } 1659 continue; 1660 } 1661 1662 // Sort the symbols by offset within the section. 1663 std::sort(List.begin(), List.end(), 1664 [&](const SymbolCU &A, const SymbolCU &B) { 1665 unsigned IA = A.Sym ? Asm->OutStreamer->GetSymbolOrder(A.Sym) : 0; 1666 unsigned IB = B.Sym ? Asm->OutStreamer->GetSymbolOrder(B.Sym) : 0; 1667 1668 // Symbols with no order assigned should be placed at the end. 1669 // (e.g. section end labels) 1670 if (IA == 0) 1671 return false; 1672 if (IB == 0) 1673 return true; 1674 return IA < IB; 1675 }); 1676 1677 // Build spans between each label. 1678 const MCSymbol *StartSym = List[0].Sym; 1679 for (size_t n = 1, e = List.size(); n < e; n++) { 1680 const SymbolCU &Prev = List[n - 1]; 1681 const SymbolCU &Cur = List[n]; 1682 1683 // Try and build the longest span we can within the same CU. 1684 if (Cur.CU != Prev.CU) { 1685 ArangeSpan Span; 1686 Span.Start = StartSym; 1687 Span.End = Cur.Sym; 1688 Spans[Prev.CU].push_back(Span); 1689 StartSym = Cur.Sym; 1690 } 1691 } 1692 } 1693 1694 // Start the dwarf aranges section. 1695 Asm->OutStreamer->SwitchSection( 1696 Asm->getObjFileLowering().getDwarfARangesSection()); 1697 1698 unsigned PtrSize = Asm->getDataLayout().getPointerSize(); 1699 1700 // Build a list of CUs used. 1701 std::vector<DwarfCompileUnit *> CUs; 1702 for (const auto &it : Spans) { 1703 DwarfCompileUnit *CU = it.first; 1704 CUs.push_back(CU); 1705 } 1706 1707 // Sort the CU list (again, to ensure consistent output order). 1708 std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) { 1709 return A->getUniqueID() < B->getUniqueID(); 1710 }); 1711 1712 // Emit an arange table for each CU we used. 1713 for (DwarfCompileUnit *CU : CUs) { 1714 std::vector<ArangeSpan> &List = Spans[CU]; 1715 1716 // Describe the skeleton CU's offset and length, not the dwo file's. 1717 if (auto *Skel = CU->getSkeleton()) 1718 CU = Skel; 1719 1720 // Emit size of content not including length itself. 1721 unsigned ContentSize = 1722 sizeof(int16_t) + // DWARF ARange version number 1723 sizeof(int32_t) + // Offset of CU in the .debug_info section 1724 sizeof(int8_t) + // Pointer Size (in bytes) 1725 sizeof(int8_t); // Segment Size (in bytes) 1726 1727 unsigned TupleSize = PtrSize * 2; 1728 1729 // 7.20 in the Dwarf specs requires the table to be aligned to a tuple. 1730 unsigned Padding = 1731 OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize); 1732 1733 ContentSize += Padding; 1734 ContentSize += (List.size() + 1) * TupleSize; 1735 1736 // For each compile unit, write the list of spans it covers. 1737 Asm->OutStreamer->AddComment("Length of ARange Set"); 1738 Asm->EmitInt32(ContentSize); 1739 Asm->OutStreamer->AddComment("DWARF Arange version number"); 1740 Asm->EmitInt16(dwarf::DW_ARANGES_VERSION); 1741 Asm->OutStreamer->AddComment("Offset Into Debug Info Section"); 1742 Asm->emitDwarfSymbolReference(CU->getLabelBegin()); 1743 Asm->OutStreamer->AddComment("Address Size (in bytes)"); 1744 Asm->EmitInt8(PtrSize); 1745 Asm->OutStreamer->AddComment("Segment Size (in bytes)"); 1746 Asm->EmitInt8(0); 1747 1748 Asm->OutStreamer->EmitFill(Padding, 0xff); 1749 1750 for (const ArangeSpan &Span : List) { 1751 Asm->EmitLabelReference(Span.Start, PtrSize); 1752 1753 // Calculate the size as being from the span start to it's end. 1754 if (Span.End) { 1755 Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize); 1756 } else { 1757 // For symbols without an end marker (e.g. common), we 1758 // write a single arange entry containing just that one symbol. 1759 uint64_t Size = SymSize[Span.Start]; 1760 if (Size == 0) 1761 Size = 1; 1762 1763 Asm->OutStreamer->EmitIntValue(Size, PtrSize); 1764 } 1765 } 1766 1767 Asm->OutStreamer->AddComment("ARange terminator"); 1768 Asm->OutStreamer->EmitIntValue(0, PtrSize); 1769 Asm->OutStreamer->EmitIntValue(0, PtrSize); 1770 } 1771} 1772 1773// Emit visible names into a debug ranges section. 1774void DwarfDebug::emitDebugRanges() { 1775 // Start the dwarf ranges section. 1776 Asm->OutStreamer->SwitchSection( 1777 Asm->getObjFileLowering().getDwarfRangesSection()); 1778 1779 // Size for our labels. 1780 unsigned char Size = Asm->getDataLayout().getPointerSize(); 1781 1782 // Grab the specific ranges for the compile units in the module. 1783 for (const auto &I : CUMap) { 1784 DwarfCompileUnit *TheCU = I.second; 1785 1786 if (auto *Skel = TheCU->getSkeleton()) 1787 TheCU = Skel; 1788 1789 // Iterate over the misc ranges for the compile units in the module. 1790 for (const RangeSpanList &List : TheCU->getRangeLists()) { 1791 // Emit our symbol so we can find the beginning of the range. 1792 Asm->OutStreamer->EmitLabel(List.getSym()); 1793 1794 for (const RangeSpan &Range : List.getRanges()) { 1795 const MCSymbol *Begin = Range.getStart(); 1796 const MCSymbol *End = Range.getEnd(); 1797 assert(Begin && "Range without a begin symbol?"); 1798 assert(End && "Range without an end symbol?"); 1799 if (auto *Base = TheCU->getBaseAddress()) { 1800 Asm->EmitLabelDifference(Begin, Base, Size); 1801 Asm->EmitLabelDifference(End, Base, Size); 1802 } else { 1803 Asm->OutStreamer->EmitSymbolValue(Begin, Size); 1804 Asm->OutStreamer->EmitSymbolValue(End, Size); 1805 } 1806 } 1807 1808 // And terminate the list with two 0 values. 1809 Asm->OutStreamer->EmitIntValue(0, Size); 1810 Asm->OutStreamer->EmitIntValue(0, Size); 1811 } 1812 } 1813} 1814 1815// DWARF5 Experimental Separate Dwarf emitters. 1816 1817void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die, 1818 std::unique_ptr<DwarfUnit> NewU) { 1819 NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name, 1820 U.getCUNode()->getSplitDebugFilename()); 1821 1822 if (!CompilationDir.empty()) 1823 NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir); 1824 1825 addGnuPubAttributes(*NewU, Die); 1826 1827 SkeletonHolder.addUnit(std::move(NewU)); 1828} 1829 1830// This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list, 1831// DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id, 1832// DW_AT_addr_base, DW_AT_ranges_base. 1833DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) { 1834 1835 auto OwnedUnit = make_unique<DwarfCompileUnit>( 1836 CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder); 1837 DwarfCompileUnit &NewCU = *OwnedUnit; 1838 NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection()); 1839 1840 NewCU.initStmtList(); 1841 1842 initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit)); 1843 1844 return NewCU; 1845} 1846 1847// Emit the .debug_info.dwo section for separated dwarf. This contains the 1848// compile units that would normally be in debug_info. 1849void DwarfDebug::emitDebugInfoDWO() { 1850 assert(useSplitDwarf() && "No split dwarf debug info?"); 1851 // Don't emit relocations into the dwo file. 1852 InfoHolder.emitUnits(/* UseOffsets */ true); 1853} 1854 1855// Emit the .debug_abbrev.dwo section for separated dwarf. This contains the 1856// abbreviations for the .debug_info.dwo section. 1857void DwarfDebug::emitDebugAbbrevDWO() { 1858 assert(useSplitDwarf() && "No split dwarf?"); 1859 InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection()); 1860} 1861 1862void DwarfDebug::emitDebugLineDWO() { 1863 assert(useSplitDwarf() && "No split dwarf?"); 1864 Asm->OutStreamer->SwitchSection( 1865 Asm->getObjFileLowering().getDwarfLineDWOSection()); 1866 SplitTypeUnitFileTable.Emit(*Asm->OutStreamer); 1867} 1868 1869// Emit the .debug_str.dwo section for separated dwarf. This contains the 1870// string section and is identical in format to traditional .debug_str 1871// sections. 1872void DwarfDebug::emitDebugStrDWO() { 1873 assert(useSplitDwarf() && "No split dwarf?"); 1874 MCSection *OffSec = Asm->getObjFileLowering().getDwarfStrOffDWOSection(); 1875 InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(), 1876 OffSec); 1877} 1878 1879MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) { 1880 if (!useSplitDwarf()) 1881 return nullptr; 1882 if (SingleCU) 1883 SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory()); 1884 return &SplitTypeUnitFileTable; 1885} 1886 1887static uint64_t makeTypeSignature(StringRef Identifier) { 1888 MD5 Hash; 1889 Hash.update(Identifier); 1890 // ... take the least significant 8 bytes and return those. Our MD5 1891 // implementation always returns its results in little endian, swap bytes 1892 // appropriately. 1893 MD5::MD5Result Result; 1894 Hash.final(Result); 1895 return support::endian::read64le(Result + 8); 1896} 1897 1898void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU, 1899 StringRef Identifier, DIE &RefDie, 1900 const DICompositeType *CTy) { 1901 // Fast path if we're building some type units and one has already used the 1902 // address pool we know we're going to throw away all this work anyway, so 1903 // don't bother building dependent types. 1904 if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed()) 1905 return; 1906 1907 const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy]; 1908 if (TU) { 1909 CU.addDIETypeSignature(RefDie, *TU); 1910 return; 1911 } 1912 1913 bool TopLevelType = TypeUnitsUnderConstruction.empty(); 1914 AddrPool.resetUsedFlag(); 1915 1916 auto OwnedUnit = make_unique<DwarfTypeUnit>( 1917 InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm, 1918 this, &InfoHolder, getDwoLineTable(CU)); 1919 DwarfTypeUnit &NewTU = *OwnedUnit; 1920 DIE &UnitDie = NewTU.getUnitDie(); 1921 TU = &NewTU; 1922 TypeUnitsUnderConstruction.push_back( 1923 std::make_pair(std::move(OwnedUnit), CTy)); 1924 1925 NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2, 1926 CU.getLanguage()); 1927 1928 uint64_t Signature = makeTypeSignature(Identifier); 1929 NewTU.setTypeSignature(Signature); 1930 1931 if (useSplitDwarf()) 1932 NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection()); 1933 else { 1934 CU.applyStmtList(UnitDie); 1935 NewTU.initSection( 1936 Asm->getObjFileLowering().getDwarfTypesSection(Signature)); 1937 } 1938 1939 NewTU.setType(NewTU.createTypeDIE(CTy)); 1940 1941 if (TopLevelType) { 1942 auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction); 1943 TypeUnitsUnderConstruction.clear(); 1944 1945 // Types referencing entries in the address table cannot be placed in type 1946 // units. 1947 if (AddrPool.hasBeenUsed()) { 1948 1949 // Remove all the types built while building this type. 1950 // This is pessimistic as some of these types might not be dependent on 1951 // the type that used an address. 1952 for (const auto &TU : TypeUnitsToAdd) 1953 DwarfTypeUnits.erase(TU.second); 1954 1955 // Construct this type in the CU directly. 1956 // This is inefficient because all the dependent types will be rebuilt 1957 // from scratch, including building them in type units, discovering that 1958 // they depend on addresses, throwing them out and rebuilding them. 1959 CU.constructTypeDIE(RefDie, cast<DICompositeType>(CTy)); 1960 return; 1961 } 1962 1963 // If the type wasn't dependent on fission addresses, finish adding the type 1964 // and all its dependent types. 1965 for (auto &TU : TypeUnitsToAdd) 1966 InfoHolder.addUnit(std::move(TU.first)); 1967 } 1968 CU.addDIETypeSignature(RefDie, NewTU); 1969} 1970 1971// Accelerator table mutators - add each name along with its companion 1972// DIE to the proper table while ensuring that the name that we're going 1973// to reference is in the string table. We do this since the names we 1974// add may not only be identical to the names in the DIE. 1975void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) { 1976 if (!useDwarfAccelTables()) 1977 return; 1978 AccelNames.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); 1979} 1980 1981void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) { 1982 if (!useDwarfAccelTables()) 1983 return; 1984 AccelObjC.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); 1985} 1986 1987void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) { 1988 if (!useDwarfAccelTables()) 1989 return; 1990 AccelNamespace.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); 1991} 1992 1993void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) { 1994 if (!useDwarfAccelTables()) 1995 return; 1996 AccelTypes.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); 1997} 1998