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/CodeGen/AsmPrinter.h" 19 #include "llvm/CodeGen/DIE.h" 20 #include "llvm/Target/TargetMachine.h" 21 #include <optional> 22 #include <string> 23 24 namespace llvm { 25 26 class ConstantFP; 27 class ConstantInt; 28 class DwarfCompileUnit; 29 class MCDwarfDwoLineTable; 30 class MCSymbol; 31 32 //===----------------------------------------------------------------------===// 33 /// This dwarf writer support class manages information associated with a 34 /// source file. 35 class DwarfUnit : public DIEUnit { 36 protected: 37 /// MDNode for the compile unit. 38 const DICompileUnit *CUNode; 39 40 // All DIEValues are allocated through this allocator. 41 BumpPtrAllocator DIEValueAllocator; 42 43 /// Target of Dwarf emission. 44 AsmPrinter *Asm; 45 46 /// Emitted at the end of the CU and used to compute the CU Length field. 47 MCSymbol *EndLabel = nullptr; 48 49 // Holders for some common dwarf information. 50 DwarfDebug *DD; 51 DwarfFile *DU; 52 53 /// An anonymous type for index type. Owned by DIEUnit. 54 DIE *IndexTyDie = nullptr; 55 56 /// Tracks the mapping of unit level debug information variables to debug 57 /// information entries. 58 DenseMap<const MDNode *, DIE *> MDNodeToDieMap; 59 60 /// A list of all the DIEBlocks in use. 61 std::vector<DIEBlock *> DIEBlocks; 62 63 /// A list of all the DIELocs in use. 64 std::vector<DIELoc *> DIELocs; 65 66 /// This map is used to keep track of subprogram DIEs that need 67 /// DW_AT_containing_type attribute. This attribute points to a DIE that 68 /// corresponds to the MDNode mapped with the subprogram DIE. 69 DenseMap<DIE *, const DINode *> ContainingTypeMap; 70 71 DwarfUnit(dwarf::Tag, const DICompileUnit *Node, AsmPrinter *A, DwarfDebug *DW, 72 DwarfFile *DWU); 73 74 bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie, bool Minimal); 75 76 bool isShareableAcrossCUs(const DINode *D) const; 77 78 template <typename T> addAttribute(DIEValueList & Die,dwarf::Attribute Attribute,dwarf::Form Form,T && Value)79 void addAttribute(DIEValueList &Die, dwarf::Attribute Attribute, 80 dwarf::Form Form, T &&Value) { 81 // For strict DWARF mode, only generate attributes available to current 82 // DWARF version. 83 // Attribute 0 is used when emitting form-encoded values in blocks, which 84 // don't have attributes (only forms) so we cannot detect their DWARF 85 // version compatibility here and assume they are compatible. 86 if (Attribute != 0 && Asm->TM.Options.DebugStrictDwarf && 87 DD->getDwarfVersion() < dwarf::AttributeVersion(Attribute)) 88 return; 89 90 Die.addValue(DIEValueAllocator, 91 DIEValue(Attribute, Form, std::forward<T>(Value))); 92 } 93 94 public: 95 // Accessors. getAsmPrinter()96 AsmPrinter* getAsmPrinter() const { return Asm; } getEndLabel()97 MCSymbol *getEndLabel() const { return EndLabel; } getLanguage()98 uint16_t getLanguage() const { return CUNode->getSourceLanguage(); } getCUNode()99 const DICompileUnit *getCUNode() const { return CUNode; } getDwarfDebug()100 DwarfDebug &getDwarfDebug() const { return *DD; } 101 102 /// Return true if this compile unit has something to write out. hasContent()103 bool hasContent() const { return getUnitDie().hasChildren(); } 104 105 /// Get string containing language specific context for a global name. 106 /// 107 /// Walks the metadata parent chain in a language specific manner (using the 108 /// compile unit language) and returns it as a string. This is done at the 109 /// metadata level because DIEs may not currently have been added to the 110 /// parent context and walking the DIEs looking for names is more expensive 111 /// than walking the metadata. 112 std::string getParentContextString(const DIScope *Context) const; 113 114 /// Add a new global name to the compile unit. 115 virtual void addGlobalName(StringRef Name, const DIE &Die, 116 const DIScope *Context) = 0; 117 118 /// Add a new global type to the compile unit. 119 virtual void addGlobalType(const DIType *Ty, const DIE &Die, 120 const DIScope *Context) = 0; 121 122 /// Returns the DIE map slot for the specified debug variable. 123 /// 124 /// We delegate the request to DwarfDebug when the MDNode can be part of the 125 /// type system, since DIEs for the type system can be shared across CUs and 126 /// the mappings are kept in DwarfDebug. 127 DIE *getDIE(const DINode *D) const; 128 129 /// Returns a fresh newly allocated DIELoc. getDIELoc()130 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; } 131 132 /// Insert DIE into the map. 133 /// 134 /// We delegate the request to DwarfDebug when the MDNode can be part of the 135 /// type system, since DIEs for the type system can be shared across CUs and 136 /// the mappings are kept in DwarfDebug. 137 void insertDIE(const DINode *Desc, DIE *D); 138 139 void insertDIE(DIE *D); 140 141 /// Add a flag that is true to the DIE. 142 void addFlag(DIE &Die, dwarf::Attribute Attribute); 143 144 /// Add an unsigned integer attribute data and value. 145 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute, 146 std::optional<dwarf::Form> Form, uint64_t Integer); 147 148 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer); 149 150 /// Add an signed integer attribute data and value. 151 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute, 152 std::optional<dwarf::Form> Form, int64_t Integer); 153 154 void addSInt(DIELoc &Die, std::optional<dwarf::Form> Form, int64_t Integer); 155 156 /// Add a string attribute data and value. 157 /// 158 /// We always emit a reference to the string pool instead of immediate 159 /// strings so that DIEs have more predictable sizes. In the case of split 160 /// dwarf we emit an index into another table which gets us the static offset 161 /// into the string table. 162 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str); 163 164 /// Add a Dwarf label attribute data and value. 165 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form, 166 const MCSymbol *Label); 167 168 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label); 169 170 /// Add an offset into a section attribute data and value. 171 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer); 172 173 /// Add a dwarf op address data and value using the form given and an 174 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index. 175 void addOpAddress(DIELoc &Die, const MCSymbol *Sym); 176 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label); 177 178 /// Add a label delta attribute data and value. 179 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute, 180 const MCSymbol *Hi, const MCSymbol *Lo); 181 182 /// Add a DIE attribute data and value. 183 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry); 184 185 /// Add a DIE attribute data and value. 186 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry); 187 188 /// Add a type's DW_AT_signature and set the declaration flag. 189 void addDIETypeSignature(DIE &Die, uint64_t Signature); 190 191 /// Add block data. 192 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc); 193 194 /// Add block data. 195 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block); 196 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form, 197 DIEBlock *Block); 198 199 /// Add location information to specified debug information entry. 200 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File); 201 void addSourceLine(DIE &Die, const DILocalVariable *V); 202 void addSourceLine(DIE &Die, const DIGlobalVariable *G); 203 void addSourceLine(DIE &Die, const DISubprogram *SP); 204 void addSourceLine(DIE &Die, const DILabel *L); 205 void addSourceLine(DIE &Die, const DIType *Ty); 206 void addSourceLine(DIE &Die, const DIObjCProperty *Ty); 207 208 /// Add constant value entry in variable DIE. 209 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty); 210 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty); 211 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned); 212 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty); 213 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val); 214 215 /// Add constant value entry in variable DIE. 216 void addConstantFPValue(DIE &Die, const ConstantFP *CFP); 217 218 /// Add a linkage name, if it isn't empty. 219 void addLinkageName(DIE &Die, StringRef LinkageName); 220 221 /// Add template parameters in buffer. 222 void addTemplateParams(DIE &Buffer, DINodeArray TParams); 223 224 /// Add thrown types. 225 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); 226 227 /// Add the accessibility attribute. 228 void addAccess(DIE &Die, DINode::DIFlags Flags); 229 230 /// Add a new type attribute to the specified entity. 231 /// 232 /// This takes and attribute parameter because DW_AT_friend attributes are 233 /// also type references. 234 void addType(DIE &Entity, const DIType *Ty, 235 dwarf::Attribute Attribute = dwarf::DW_AT_type); 236 237 DIE *getOrCreateNameSpace(const DINamespace *NS); 238 DIE *getOrCreateModule(const DIModule *M); 239 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false); 240 241 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie, 242 bool SkipSPAttributes = false); 243 244 /// Creates type DIE with specific context. 245 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty); 246 247 /// Find existing DIE or create new DIE for the given type. 248 DIE *getOrCreateTypeDIE(const MDNode *TyNode); 249 250 /// Get context owner's DIE. 251 DIE *getOrCreateContextDIE(const DIScope *Context); 252 253 /// Construct DIEs for types that contain vtables. 254 void constructContainingTypeDIEs(); 255 256 /// Construct function argument DIEs. 257 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args); 258 259 /// Create a DIE with the given Tag, add the DIE to its parent, and 260 /// call insertDIE if MD is not null. 261 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr); 262 useSegmentedStringOffsetsTable()263 bool useSegmentedStringOffsetsTable() const { 264 return DD->useSegmentedStringOffsetsTable(); 265 } 266 267 /// Compute the size of a header for this unit, not including the initial 268 /// length field. getHeaderSize()269 virtual unsigned getHeaderSize() const { 270 return sizeof(int16_t) + // DWARF version number 271 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section 272 sizeof(int8_t) + // Pointer Size (in bytes) 273 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t) 274 : 0); // DWARF v5 unit type 275 } 276 277 /// Emit the header for this unit, not including the initial length field. 278 virtual void emitHeader(bool UseOffsets) = 0; 279 280 /// Add the DW_AT_str_offsets_base attribute to the unit DIE. 281 void addStringOffsetsStart(); 282 283 /// Add the DW_AT_rnglists_base attribute to the unit DIE. 284 void addRnglistsBase(); 285 286 virtual DwarfCompileUnit &getCU() = 0; 287 288 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy); 289 290 /// addSectionDelta - Add a label delta attribute data and value. 291 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi, 292 const MCSymbol *Lo); 293 294 /// Add a Dwarf section label attribute data and value. 295 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute, 296 const MCSymbol *Label, const MCSymbol *Sec); 297 298 /// Add DW_TAG_LLVM_annotation. 299 void addAnnotation(DIE &Buffer, DINodeArray Annotations); 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 /// Emit the common part of the header for this unit. 315 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT); 316 317 private: 318 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy); 319 void constructTypeDIE(DIE &Buffer, const DIStringType *BTy); 320 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy); 321 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy); 322 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy); 323 void constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR, 324 DIE *IndexTy); 325 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy); 326 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy); 327 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT); 328 void constructTemplateTypeParameterDIE(DIE &Buffer, 329 const DITemplateTypeParameter *TP); 330 void constructTemplateValueParameterDIE(DIE &Buffer, 331 const DITemplateValueParameter *TVP); 332 333 /// Return the default lower bound for an array. 334 /// 335 /// If the DWARF version doesn't handle the language, return -1. 336 int64_t getDefaultLowerBound() const; 337 338 /// Get an anonymous type for index type. 339 DIE *getIndexTyDie(); 340 341 /// Set D as anonymous type for index which can be reused later. setIndexTyDie(DIE * D)342 void setIndexTyDie(DIE *D) { IndexTyDie = D; } 343 344 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0; 345 346 /// If this is a named finished type then include it in the list of types for 347 /// the accelerator tables. 348 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty, 349 const DIE &TyDIE); 350 351 virtual bool isDwoUnit() const = 0; 352 const MCSymbol *getCrossSectionRelativeBaseAddress() const override; 353 354 /// Returns 'true' if the current DwarfVersion is compatible 355 /// with the specified \p Version. 356 bool isCompatibleWithVersion(uint16_t Version) const; 357 }; 358 359 class DwarfTypeUnit final : public DwarfUnit { 360 uint64_t TypeSignature; 361 const DIE *Ty; 362 DwarfCompileUnit &CU; 363 MCDwarfDwoLineTable *SplitLineTable; 364 bool UsedLineTable = false; 365 366 unsigned getOrCreateSourceID(const DIFile *File) override; 367 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override; 368 bool isDwoUnit() const override; 369 370 public: 371 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW, 372 DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr); 373 setTypeSignature(uint64_t Signature)374 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; } setType(const DIE * Ty)375 void setType(const DIE *Ty) { this->Ty = Ty; } 376 377 /// Emit the header for this unit, not including the initial length field. 378 void emitHeader(bool UseOffsets) override; getHeaderSize()379 unsigned getHeaderSize() const override { 380 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature 381 Asm->getDwarfOffsetByteSize(); // Type DIE Offset 382 } 383 void addGlobalName(StringRef Name, const DIE &Die, 384 const DIScope *Context) override; 385 void addGlobalType(const DIType *Ty, const DIE &Die, 386 const DIScope *Context) override; getCU()387 DwarfCompileUnit &getCU() override { return CU; } 388 }; 389 } // end llvm namespace 390 #endif 391