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 /// A numeric ID unique among all CUs in the module 38 unsigned UniqueID; 39 /// MDNode for the compile unit. 40 const DICompileUnit *CUNode; 41 42 // All DIEValues are allocated through this allocator. 43 BumpPtrAllocator DIEValueAllocator; 44 45 /// Target of Dwarf emission. 46 AsmPrinter *Asm; 47 48 /// The start of the unit within its section. 49 MCSymbol *LabelBegin = nullptr; 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 = nullptr; 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, 77 DwarfDebug *DW, DwarfFile *DWU, unsigned UniqueID = 0); 78 79 bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie, bool Minimal); 80 81 bool isShareableAcrossCUs(const DINode *D) const; 82 83 template <typename T> addAttribute(DIEValueList & Die,dwarf::Attribute Attribute,dwarf::Form Form,T && Value)84 void addAttribute(DIEValueList &Die, dwarf::Attribute Attribute, 85 dwarf::Form Form, T &&Value) { 86 // For strict DWARF mode, only generate attributes available to current 87 // DWARF version. 88 // Attribute 0 is used when emitting form-encoded values in blocks, which 89 // don't have attributes (only forms) so we cannot detect their DWARF 90 // version compatibility here and assume they are compatible. 91 if (Attribute != 0 && Asm->TM.Options.DebugStrictDwarf && 92 DD->getDwarfVersion() < dwarf::AttributeVersion(Attribute)) 93 return; 94 95 Die.addValue(DIEValueAllocator, 96 DIEValue(Attribute, Form, std::forward<T>(Value))); 97 } 98 99 public: 100 /// Gets Unique ID for this unit. getUniqueID()101 unsigned getUniqueID() const { return UniqueID; } 102 // Accessors. getAsmPrinter()103 AsmPrinter* getAsmPrinter() const { return Asm; } 104 /// Get the the symbol for start of the section for this unit. getLabelBegin()105 MCSymbol *getLabelBegin() const { 106 assert(LabelBegin && "LabelBegin is not initialized"); 107 return LabelBegin; 108 } getEndLabel()109 MCSymbol *getEndLabel() const { return EndLabel; } getLanguage()110 uint16_t getLanguage() const { return CUNode->getSourceLanguage(); } getCUNode()111 const DICompileUnit *getCUNode() const { return CUNode; } getDwarfDebug()112 DwarfDebug &getDwarfDebug() const { return *DD; } 113 114 /// Return true if this compile unit has something to write out. hasContent()115 bool hasContent() const { return getUnitDie().hasChildren(); } 116 117 /// Get string containing language specific context for a global name. 118 /// 119 /// Walks the metadata parent chain in a language specific manner (using the 120 /// compile unit language) and returns it as a string. This is done at the 121 /// metadata level because DIEs may not currently have been added to the 122 /// parent context and walking the DIEs looking for names is more expensive 123 /// than walking the metadata. 124 std::string getParentContextString(const DIScope *Context) const; 125 126 /// Add a new global name to the compile unit. 127 virtual void addGlobalName(StringRef Name, const DIE &Die, 128 const DIScope *Context) = 0; 129 130 /// Add a new global type to the compile unit. 131 virtual void addGlobalTypeImpl(const DIType *Ty, const DIE &Die, 132 const DIScope *Context) = 0; 133 134 void addGlobalType(const DIType *Ty, const DIE &Die, const DIScope *Context); 135 136 /// Returns the DIE map slot for the specified debug variable. 137 /// 138 /// We delegate the request to DwarfDebug when the MDNode can be part of the 139 /// type system, since DIEs for the type system can be shared across CUs and 140 /// the mappings are kept in DwarfDebug. 141 DIE *getDIE(const DINode *D) const; 142 143 /// Returns a fresh newly allocated DIELoc. getDIELoc()144 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; } 145 146 /// Insert DIE into the map. 147 /// 148 /// We delegate the request to DwarfDebug when the MDNode can be part of the 149 /// type system, since DIEs for the type system can be shared across CUs and 150 /// the mappings are kept in DwarfDebug. 151 void insertDIE(const DINode *Desc, DIE *D); 152 153 void insertDIE(DIE *D); 154 155 /// Add a flag that is true to the DIE. 156 void addFlag(DIE &Die, dwarf::Attribute Attribute); 157 158 /// Add an unsigned integer attribute data and value. 159 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute, 160 std::optional<dwarf::Form> Form, uint64_t Integer); 161 162 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer); 163 164 /// Add an signed integer attribute data and value. 165 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute, 166 std::optional<dwarf::Form> Form, int64_t Integer); 167 168 void addSInt(DIELoc &Die, std::optional<dwarf::Form> Form, int64_t Integer); 169 170 /// Add a string attribute data and value. 171 /// 172 /// We always emit a reference to the string pool instead of immediate 173 /// strings so that DIEs have more predictable sizes. In the case of split 174 /// dwarf we emit an index into another table which gets us the static offset 175 /// into the string table. 176 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str); 177 178 /// Add a Dwarf label attribute data and value. 179 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form, 180 const MCSymbol *Label); 181 182 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label); 183 184 /// Add an offset into a section attribute data and value. 185 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer); 186 187 /// Add a dwarf op address data and value using the form given and an 188 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index. 189 void addOpAddress(DIELoc &Die, const MCSymbol *Sym); 190 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label); 191 192 /// Add a label delta attribute data and value. 193 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute, 194 const MCSymbol *Hi, const MCSymbol *Lo); 195 196 /// Add a DIE attribute data and value. 197 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry); 198 199 /// Add a DIE attribute data and value. 200 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry); 201 202 /// Add a type's DW_AT_signature and set the declaration flag. 203 void addDIETypeSignature(DIE &Die, uint64_t Signature); 204 205 /// Add block data. 206 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc); 207 208 /// Add block data. 209 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block); 210 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form, 211 DIEBlock *Block); 212 213 /// Add location information to specified debug information entry. 214 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File); 215 void addSourceLine(DIE &Die, const DILocalVariable *V); 216 void addSourceLine(DIE &Die, const DIGlobalVariable *G); 217 void addSourceLine(DIE &Die, const DISubprogram *SP); 218 void addSourceLine(DIE &Die, const DILabel *L); 219 void addSourceLine(DIE &Die, const DIType *Ty); 220 void addSourceLine(DIE &Die, const DIObjCProperty *Ty); 221 222 /// Add constant value entry in variable DIE. 223 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty); 224 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty); 225 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned); 226 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty); 227 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val); 228 229 /// Add constant value entry in variable DIE. 230 void addConstantFPValue(DIE &Die, const ConstantFP *CFP); 231 232 /// Add a linkage name, if it isn't empty. 233 void addLinkageName(DIE &Die, StringRef LinkageName); 234 235 /// Add template parameters in buffer. 236 void addTemplateParams(DIE &Buffer, DINodeArray TParams); 237 238 /// Add thrown types. 239 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); 240 241 /// Add the accessibility attribute. 242 void addAccess(DIE &Die, DINode::DIFlags Flags); 243 244 /// Add a new type attribute to the specified entity. 245 /// 246 /// This takes and attribute parameter because DW_AT_friend attributes are 247 /// also type references. 248 void addType(DIE &Entity, const DIType *Ty, 249 dwarf::Attribute Attribute = dwarf::DW_AT_type); 250 251 DIE *getOrCreateNameSpace(const DINamespace *NS); 252 DIE *getOrCreateModule(const DIModule *M); 253 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false); 254 255 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie, 256 bool SkipSPAttributes = false); 257 258 /// Creates type DIE with specific context. 259 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty); 260 261 /// Find existing DIE or create new DIE for the given type. 262 virtual DIE *getOrCreateTypeDIE(const MDNode *TyNode); 263 264 /// Get context owner's DIE. 265 virtual DIE *getOrCreateContextDIE(const DIScope *Context); 266 267 /// Construct DIEs for types that contain vtables. 268 void constructContainingTypeDIEs(); 269 270 /// Construct function argument DIEs. 271 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args); 272 273 /// Create a DIE with the given Tag, add the DIE to its parent, and 274 /// call insertDIE if MD is not null. 275 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr); 276 useSegmentedStringOffsetsTable()277 bool useSegmentedStringOffsetsTable() const { 278 return DD->useSegmentedStringOffsetsTable(); 279 } 280 281 /// Compute the size of a header for this unit, not including the initial 282 /// length field. getHeaderSize()283 virtual unsigned getHeaderSize() const { 284 return sizeof(int16_t) + // DWARF version number 285 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section 286 sizeof(int8_t) + // Pointer Size (in bytes) 287 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t) 288 : 0); // DWARF v5 unit type 289 } 290 291 /// Emit the header for this unit, not including the initial length field. 292 virtual void emitHeader(bool UseOffsets) = 0; 293 294 /// Add the DW_AT_str_offsets_base attribute to the unit DIE. 295 void addStringOffsetsStart(); 296 297 /// Add the DW_AT_rnglists_base attribute to the unit DIE. 298 void addRnglistsBase(); 299 300 virtual DwarfCompileUnit &getCU() = 0; 301 302 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy); 303 304 /// addSectionDelta - Add a label delta attribute data and value. 305 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi, 306 const MCSymbol *Lo); 307 308 /// Add a Dwarf section label attribute data and value. 309 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute, 310 const MCSymbol *Label, const MCSymbol *Sec); 311 312 /// Add DW_TAG_LLVM_annotation. 313 void addAnnotation(DIE &Buffer, DINodeArray Annotations); 314 315 /// Get context owner's DIE. 316 DIE *createTypeDIE(const DICompositeType *Ty); 317 318 protected: 319 ~DwarfUnit(); 320 321 /// Create new static data member DIE. 322 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT); 323 324 /// Look up the source ID for the given file. If none currently exists, 325 /// create a new ID and insert it in the line table. 326 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0; 327 328 /// Emit the common part of the header for this unit. 329 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT); 330 331 private: 332 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy); 333 void constructTypeDIE(DIE &Buffer, const DIStringType *BTy); 334 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy); 335 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy); 336 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy); 337 void constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR, 338 DIE *IndexTy); 339 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy); 340 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy); 341 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT); 342 void constructTemplateTypeParameterDIE(DIE &Buffer, 343 const DITemplateTypeParameter *TP); 344 void constructTemplateValueParameterDIE(DIE &Buffer, 345 const DITemplateValueParameter *TVP); 346 347 /// Return the default lower bound for an array. 348 /// 349 /// If the DWARF version doesn't handle the language, return -1. 350 int64_t getDefaultLowerBound() const; 351 352 /// Get an anonymous type for index type. 353 DIE *getIndexTyDie(); 354 355 /// Set D as anonymous type for index which can be reused later. setIndexTyDie(DIE * D)356 void setIndexTyDie(DIE *D) { IndexTyDie = D; } 357 358 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0; 359 360 /// If this is a named finished type then include it in the list of types for 361 /// the accelerator tables. 362 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty, 363 const DIE &TyDIE); 364 365 virtual bool isDwoUnit() const = 0; 366 const MCSymbol *getCrossSectionRelativeBaseAddress() const override; 367 368 /// Returns 'true' if the current DwarfVersion is compatible 369 /// with the specified \p Version. 370 bool isCompatibleWithVersion(uint16_t Version) const; 371 }; 372 373 class DwarfTypeUnit final : public DwarfUnit { 374 uint64_t TypeSignature; 375 const DIE *Ty; 376 DwarfCompileUnit &CU; 377 MCDwarfDwoLineTable *SplitLineTable; 378 bool UsedLineTable = false; 379 380 unsigned getOrCreateSourceID(const DIFile *File) override; 381 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override; 382 bool isDwoUnit() const override; 383 384 public: 385 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW, 386 DwarfFile *DWU, unsigned UniqueID, 387 MCDwarfDwoLineTable *SplitLineTable = nullptr); 388 setTypeSignature(uint64_t Signature)389 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; } 390 /// Returns Type Signature. getTypeSignature()391 uint64_t getTypeSignature() const { return TypeSignature; } setType(const DIE * Ty)392 void setType(const DIE *Ty) { this->Ty = Ty; } 393 394 /// Emit the header for this unit, not including the initial length field. 395 void emitHeader(bool UseOffsets) override; getHeaderSize()396 unsigned getHeaderSize() const override { 397 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature 398 Asm->getDwarfOffsetByteSize(); // Type DIE Offset 399 } 400 void addGlobalName(StringRef Name, const DIE &Die, 401 const DIScope *Context) override; 402 void addGlobalTypeImpl(const DIType *Ty, const DIE &Die, 403 const DIScope *Context) override; getCU()404 DwarfCompileUnit &getCU() override { return CU; } 405 }; 406 } // end llvm namespace 407 #endif 408