1 //===-- llvm/CodeGen/DwarfUnit.h - Dwarf Compile Unit ---*- C++ -*--===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains support for writing dwarf compile unit. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H 14 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H 15 16 #include "DwarfDebug.h" 17 #include "llvm/ADT/DenseMap.h" 18 #include "llvm/ADT/Optional.h" 19 #include "llvm/ADT/StringMap.h" 20 #include "llvm/CodeGen/AsmPrinter.h" 21 #include "llvm/CodeGen/DIE.h" 22 #include "llvm/IR/DIBuilder.h" 23 #include "llvm/IR/DebugInfo.h" 24 #include "llvm/MC/MCDwarf.h" 25 #include "llvm/MC/MCExpr.h" 26 #include "llvm/MC/MCSection.h" 27 28 namespace llvm { 29 30 class MachineLocation; 31 class MachineOperand; 32 class ConstantInt; 33 class ConstantFP; 34 class DbgVariable; 35 class DwarfCompileUnit; 36 37 //===----------------------------------------------------------------------===// 38 /// This dwarf writer support class manages information associated with a 39 /// source file. 40 class DwarfUnit : public DIEUnit { 41 protected: 42 /// MDNode for the compile unit. 43 const DICompileUnit *CUNode; 44 45 // All DIEValues are allocated through this allocator. 46 BumpPtrAllocator DIEValueAllocator; 47 48 /// Target of Dwarf emission. 49 AsmPrinter *Asm; 50 51 /// Emitted at the end of the CU and used to compute the CU Length field. 52 MCSymbol *EndLabel = nullptr; 53 54 // Holders for some common dwarf information. 55 DwarfDebug *DD; 56 DwarfFile *DU; 57 58 /// An anonymous type for index type. Owned by DIEUnit. 59 DIE *IndexTyDie; 60 61 /// Tracks the mapping of unit level debug information variables to debug 62 /// information entries. 63 DenseMap<const MDNode *, DIE *> MDNodeToDieMap; 64 65 /// A list of all the DIEBlocks in use. 66 std::vector<DIEBlock *> DIEBlocks; 67 68 /// A list of all the DIELocs in use. 69 std::vector<DIELoc *> DIELocs; 70 71 /// This map is used to keep track of subprogram DIEs that need 72 /// DW_AT_containing_type attribute. This attribute points to a DIE that 73 /// corresponds to the MDNode mapped with the subprogram DIE. 74 DenseMap<DIE *, const DINode *> ContainingTypeMap; 75 76 DwarfUnit(dwarf::Tag, const DICompileUnit *Node, AsmPrinter *A, DwarfDebug *DW, 77 DwarfFile *DWU); 78 79 bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie); 80 81 bool shareAcrossDWOCUs() const; 82 bool isShareableAcrossCUs(const DINode *D) const; 83 84 public: 85 // Accessors. 86 AsmPrinter* getAsmPrinter() const { return Asm; } 87 MCSymbol *getEndLabel() const { return EndLabel; } 88 uint16_t getLanguage() const { return CUNode->getSourceLanguage(); } 89 const DICompileUnit *getCUNode() const { return CUNode; } 90 91 uint16_t getDwarfVersion() const { return DD->getDwarfVersion(); } 92 93 /// Return true if this compile unit has something to write out. 94 bool hasContent() const { return getUnitDie().hasChildren(); } 95 96 /// Get string containing language specific context for a global name. 97 /// 98 /// Walks the metadata parent chain in a language specific manner (using the 99 /// compile unit language) and returns it as a string. This is done at the 100 /// metadata level because DIEs may not currently have been added to the 101 /// parent context and walking the DIEs looking for names is more expensive 102 /// than walking the metadata. 103 std::string getParentContextString(const DIScope *Context) const; 104 105 /// Add a new global name to the compile unit. 106 virtual void addGlobalName(StringRef Name, const DIE &Die, 107 const DIScope *Context) = 0; 108 109 /// Add a new global type to the compile unit. 110 virtual void addGlobalType(const DIType *Ty, const DIE &Die, 111 const DIScope *Context) = 0; 112 113 /// Returns the DIE map slot for the specified debug variable. 114 /// 115 /// We delegate the request to DwarfDebug when the MDNode can be part of the 116 /// type system, since DIEs for the type system can be shared across CUs and 117 /// the mappings are kept in DwarfDebug. 118 DIE *getDIE(const DINode *D) const; 119 120 /// Returns a fresh newly allocated DIELoc. 121 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; } 122 123 /// Insert DIE into the map. 124 /// 125 /// We delegate the request to DwarfDebug when the MDNode can be part of the 126 /// type system, since DIEs for the type system can be shared across CUs and 127 /// the mappings are kept in DwarfDebug. 128 void insertDIE(const DINode *Desc, DIE *D); 129 130 /// Add a flag that is true to the DIE. 131 void addFlag(DIE &Die, dwarf::Attribute Attribute); 132 133 /// Add an unsigned integer attribute data and value. 134 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute, 135 Optional<dwarf::Form> Form, uint64_t Integer); 136 137 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer); 138 139 /// Add an signed integer attribute data and value. 140 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute, 141 Optional<dwarf::Form> Form, int64_t Integer); 142 143 void addSInt(DIELoc &Die, Optional<dwarf::Form> Form, int64_t Integer); 144 145 /// Add a string attribute data and value. 146 /// 147 /// We always emit a reference to the string pool instead of immediate 148 /// strings so that DIEs have more predictable sizes. In the case of split 149 /// dwarf we emit an index into another table which gets us the static offset 150 /// into the string table. 151 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str); 152 153 /// Add a Dwarf label attribute data and value. 154 DIEValueList::value_iterator addLabel(DIEValueList &Die, 155 dwarf::Attribute Attribute, 156 dwarf::Form Form, 157 const MCSymbol *Label); 158 159 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label); 160 161 /// Add an offset into a section attribute data and value. 162 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer); 163 164 /// Add a dwarf op address data and value using the form given and an 165 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index. 166 void addOpAddress(DIELoc &Die, const MCSymbol *Sym); 167 168 /// Add a label delta attribute data and value. 169 void addLabelDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi, 170 const MCSymbol *Lo); 171 172 /// Add a DIE attribute data and value. 173 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry); 174 175 /// Add a DIE attribute data and value. 176 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry); 177 178 /// Add a type's DW_AT_signature and set the declaration flag. 179 void addDIETypeSignature(DIE &Die, uint64_t Signature); 180 181 /// Add block data. 182 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc); 183 184 /// Add block data. 185 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block); 186 187 /// Add location information to specified debug information entry. 188 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File); 189 void addSourceLine(DIE &Die, const DILocalVariable *V); 190 void addSourceLine(DIE &Die, const DIGlobalVariable *G); 191 void addSourceLine(DIE &Die, const DISubprogram *SP); 192 void addSourceLine(DIE &Die, const DILabel *L); 193 void addSourceLine(DIE &Die, const DIType *Ty); 194 void addSourceLine(DIE &Die, const DIObjCProperty *Ty); 195 196 /// Add constant value entry in variable DIE. 197 void addConstantValue(DIE &Die, const MachineOperand &MO, const DIType *Ty); 198 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty); 199 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty); 200 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned); 201 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val); 202 203 /// Add constant value entry in variable DIE. 204 void addConstantFPValue(DIE &Die, const MachineOperand &MO); 205 void addConstantFPValue(DIE &Die, const ConstantFP *CFP); 206 207 /// Add a linkage name, if it isn't empty. 208 void addLinkageName(DIE &Die, StringRef LinkageName); 209 210 /// Add template parameters in buffer. 211 void addTemplateParams(DIE &Buffer, DINodeArray TParams); 212 213 /// Add thrown types. 214 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); 215 216 // FIXME: Should be reformulated in terms of addComplexAddress. 217 /// Start with the address based on the location provided, and generate the 218 /// DWARF information necessary to find the actual Block variable (navigating 219 /// the Block struct) based on the starting location. Add the DWARF 220 /// information to the die. Obsolete, please use addComplexAddress instead. 221 void addBlockByrefAddress(const DbgVariable &DV, DIE &Die, 222 dwarf::Attribute Attribute, 223 const MachineLocation &Location); 224 225 /// Add a new type attribute to the specified entity. 226 /// 227 /// This takes and attribute parameter because DW_AT_friend attributes are 228 /// also type references. 229 void addType(DIE &Entity, const DIType *Ty, 230 dwarf::Attribute Attribute = dwarf::DW_AT_type); 231 232 DIE *getOrCreateNameSpace(const DINamespace *NS); 233 DIE *getOrCreateModule(const DIModule *M); 234 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false); 235 236 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie, 237 bool SkipSPAttributes = false); 238 239 /// Creates type DIE with specific context. 240 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty); 241 242 /// Find existing DIE or create new DIE for the given type. 243 DIE *getOrCreateTypeDIE(const MDNode *TyNode); 244 245 /// Get context owner's DIE. 246 DIE *getOrCreateContextDIE(const DIScope *Context); 247 248 /// Construct DIEs for types that contain vtables. 249 void constructContainingTypeDIEs(); 250 251 /// Construct function argument DIEs. 252 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args); 253 254 /// Create a DIE with the given Tag, add the DIE to its parent, and 255 /// call insertDIE if MD is not null. 256 DIE &createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N = nullptr); 257 258 bool useSegmentedStringOffsetsTable() const { 259 return DD->useSegmentedStringOffsetsTable(); 260 } 261 262 /// Compute the size of a header for this unit, not including the initial 263 /// length field. 264 virtual unsigned getHeaderSize() const { 265 return sizeof(int16_t) + // DWARF version number 266 sizeof(int32_t) + // Offset Into Abbrev. Section 267 sizeof(int8_t) + // Pointer Size (in bytes) 268 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t) 269 : 0); // DWARF v5 unit type 270 } 271 272 /// Emit the header for this unit, not including the initial length field. 273 virtual void emitHeader(bool UseOffsets) = 0; 274 275 /// Add the DW_AT_str_offsets_base attribute to the unit DIE. 276 void addStringOffsetsStart(); 277 278 /// Add the DW_AT_rnglists_base attribute to the unit DIE. 279 void addRnglistsBase(); 280 281 /// Add the DW_AT_loclists_base attribute to the unit DIE. 282 void addLoclistsBase(); 283 284 virtual DwarfCompileUnit &getCU() = 0; 285 286 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy); 287 288 /// addSectionDelta - Add a label delta attribute data and value. 289 DIE::value_iterator addSectionDelta(DIE &Die, dwarf::Attribute Attribute, 290 const MCSymbol *Hi, const MCSymbol *Lo); 291 292 /// Add a Dwarf section label attribute data and value. 293 DIE::value_iterator addSectionLabel(DIE &Die, dwarf::Attribute Attribute, 294 const MCSymbol *Label, 295 const MCSymbol *Sec); 296 297 /// If the \p File has an MD5 checksum, return it as an MD5Result 298 /// allocated in the MCContext. 299 Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const; 300 301 /// Get context owner's DIE. 302 DIE *createTypeDIE(const DICompositeType *Ty); 303 304 protected: 305 ~DwarfUnit(); 306 307 /// Create new static data member DIE. 308 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT); 309 310 /// Look up the source ID for the given file. If none currently exists, 311 /// create a new ID and insert it in the line table. 312 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0; 313 314 /// Look in the DwarfDebug map for the MDNode that corresponds to the 315 /// reference. 316 template <typename T> T *resolve(TypedDINodeRef<T> Ref) const { 317 return Ref.resolve(); 318 } 319 320 /// Emit the common part of the header for this unit. 321 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT); 322 323 private: 324 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy); 325 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy); 326 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy); 327 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy); 328 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy); 329 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy); 330 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT); 331 void constructTemplateTypeParameterDIE(DIE &Buffer, 332 const DITemplateTypeParameter *TP); 333 void constructTemplateValueParameterDIE(DIE &Buffer, 334 const DITemplateValueParameter *TVP); 335 336 /// Return the default lower bound for an array. 337 /// 338 /// If the DWARF version doesn't handle the language, return -1. 339 int64_t getDefaultLowerBound() const; 340 341 /// Get an anonymous type for index type. 342 DIE *getIndexTyDie(); 343 344 /// Set D as anonymous type for index which can be reused later. 345 void setIndexTyDie(DIE *D) { IndexTyDie = D; } 346 347 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0; 348 349 /// If this is a named finished type then include it in the list of types for 350 /// the accelerator tables. 351 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty, 352 const DIE &TyDIE); 353 354 virtual bool isDwoUnit() const = 0; 355 const MCSymbol *getCrossSectionRelativeBaseAddress() const override; 356 }; 357 358 class DwarfTypeUnit final : public DwarfUnit { 359 uint64_t TypeSignature; 360 const DIE *Ty; 361 DwarfCompileUnit &CU; 362 MCDwarfDwoLineTable *SplitLineTable; 363 bool UsedLineTable = false; 364 365 unsigned getOrCreateSourceID(const DIFile *File) override; 366 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override; 367 bool isDwoUnit() const override; 368 369 public: 370 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW, 371 DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr); 372 373 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; } 374 void setType(const DIE *Ty) { this->Ty = Ty; } 375 376 /// Emit the header for this unit, not including the initial length field. 377 void emitHeader(bool UseOffsets) override; 378 unsigned getHeaderSize() const override { 379 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature 380 sizeof(uint32_t); // Type DIE Offset 381 } 382 void addGlobalName(StringRef Name, const DIE &Die, 383 const DIScope *Context) override; 384 void addGlobalType(const DIType *Ty, const DIE &Die, 385 const DIScope *Context) override; 386 DwarfCompileUnit &getCU() override { return CU; } 387 }; 388 } // end llvm namespace 389 #endif 390