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