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 void insertDIE(DIE *D); 131 132 /// Add a flag that is true to the DIE. 133 void addFlag(DIE &Die, dwarf::Attribute Attribute); 134 135 /// Add an unsigned integer attribute data and value. 136 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute, 137 Optional<dwarf::Form> Form, uint64_t Integer); 138 139 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer); 140 141 /// Add an signed integer attribute data and value. 142 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute, 143 Optional<dwarf::Form> Form, int64_t Integer); 144 145 void addSInt(DIELoc &Die, Optional<dwarf::Form> Form, int64_t Integer); 146 147 /// Add a string attribute data and value. 148 /// 149 /// We always emit a reference to the string pool instead of immediate 150 /// strings so that DIEs have more predictable sizes. In the case of split 151 /// dwarf we emit an index into another table which gets us the static offset 152 /// into the string table. 153 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str); 154 155 /// Add a Dwarf label attribute data and value. 156 DIEValueList::value_iterator addLabel(DIEValueList &Die, 157 dwarf::Attribute Attribute, 158 dwarf::Form Form, 159 const MCSymbol *Label); 160 161 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label); 162 163 /// Add an offset into a section attribute data and value. 164 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer); 165 166 /// Add a dwarf op address data and value using the form given and an 167 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index. 168 void addOpAddress(DIELoc &Die, const MCSymbol *Sym); 169 170 /// Add a label delta attribute data and value. 171 void addLabelDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi, 172 const MCSymbol *Lo); 173 174 /// Add a DIE attribute data and value. 175 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry); 176 177 /// Add a DIE attribute data and value. 178 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry); 179 180 /// Add a type's DW_AT_signature and set the declaration flag. 181 void addDIETypeSignature(DIE &Die, uint64_t Signature); 182 183 /// Add block data. 184 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc); 185 186 /// Add block data. 187 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block); 188 189 /// Add location information to specified debug information entry. 190 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File); 191 void addSourceLine(DIE &Die, const DILocalVariable *V); 192 void addSourceLine(DIE &Die, const DIGlobalVariable *G); 193 void addSourceLine(DIE &Die, const DISubprogram *SP); 194 void addSourceLine(DIE &Die, const DILabel *L); 195 void addSourceLine(DIE &Die, const DIType *Ty); 196 void addSourceLine(DIE &Die, const DIObjCProperty *Ty); 197 198 /// Add constant value entry in variable DIE. 199 void addConstantValue(DIE &Die, const MachineOperand &MO, const DIType *Ty); 200 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty); 201 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty); 202 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned); 203 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty); 204 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val); 205 206 /// Add constant value entry in variable DIE. 207 void addConstantFPValue(DIE &Die, const MachineOperand &MO); 208 void addConstantFPValue(DIE &Die, const ConstantFP *CFP); 209 210 /// Add a linkage name, if it isn't empty. 211 void addLinkageName(DIE &Die, StringRef LinkageName); 212 213 /// Add template parameters in buffer. 214 void addTemplateParams(DIE &Buffer, DINodeArray TParams); 215 216 /// Add thrown types. 217 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); 218 219 // FIXME: Should be reformulated in terms of addComplexAddress. 220 /// Start with the address based on the location provided, and generate the 221 /// DWARF information necessary to find the actual Block variable (navigating 222 /// the Block struct) based on the starting location. Add the DWARF 223 /// information to the die. Obsolete, please use addComplexAddress instead. 224 void addBlockByrefAddress(const DbgVariable &DV, DIE &Die, 225 dwarf::Attribute Attribute, 226 const MachineLocation &Location); 227 228 /// Add a new type attribute to the specified entity. 229 /// 230 /// This takes and attribute parameter because DW_AT_friend attributes are 231 /// also type references. 232 void addType(DIE &Entity, const DIType *Ty, 233 dwarf::Attribute Attribute = dwarf::DW_AT_type); 234 235 DIE *getOrCreateNameSpace(const DINamespace *NS); 236 DIE *getOrCreateModule(const DIModule *M); 237 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false); 238 239 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie, 240 bool SkipSPAttributes = false); 241 242 /// Creates type DIE with specific context. 243 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty); 244 245 /// Find existing DIE or create new DIE for the given type. 246 DIE *getOrCreateTypeDIE(const MDNode *TyNode); 247 248 /// Get context owner's DIE. 249 DIE *getOrCreateContextDIE(const DIScope *Context); 250 251 /// Construct DIEs for types that contain vtables. 252 void constructContainingTypeDIEs(); 253 254 /// Construct function argument DIEs. 255 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args); 256 257 /// Create a DIE with the given Tag, add the DIE to its parent, and 258 /// call insertDIE if MD is not null. 259 DIE &createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N = nullptr); 260 261 bool useSegmentedStringOffsetsTable() const { 262 return DD->useSegmentedStringOffsetsTable(); 263 } 264 265 /// Compute the size of a header for this unit, not including the initial 266 /// length field. 267 virtual unsigned getHeaderSize() const { 268 return sizeof(int16_t) + // DWARF version number 269 sizeof(int32_t) + // Offset Into Abbrev. Section 270 sizeof(int8_t) + // Pointer Size (in bytes) 271 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t) 272 : 0); // DWARF v5 unit type 273 } 274 275 /// Emit the header for this unit, not including the initial length field. 276 virtual void emitHeader(bool UseOffsets) = 0; 277 278 /// Add the DW_AT_str_offsets_base attribute to the unit DIE. 279 void addStringOffsetsStart(); 280 281 /// Add the DW_AT_rnglists_base attribute to the unit DIE. 282 void addRnglistsBase(); 283 284 /// Add the DW_AT_loclists_base attribute to the unit DIE. 285 void addLoclistsBase(); 286 287 virtual DwarfCompileUnit &getCU() = 0; 288 289 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy); 290 291 /// addSectionDelta - Add a label delta attribute data and value. 292 DIE::value_iterator addSectionDelta(DIE &Die, dwarf::Attribute Attribute, 293 const MCSymbol *Hi, const MCSymbol *Lo); 294 295 /// Add a Dwarf section label attribute data and value. 296 DIE::value_iterator addSectionLabel(DIE &Die, dwarf::Attribute Attribute, 297 const MCSymbol *Label, 298 const MCSymbol *Sec); 299 300 /// If the \p File has an MD5 checksum, return it as an MD5Result 301 /// allocated in the MCContext. 302 Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const; 303 304 /// Get context owner's DIE. 305 DIE *createTypeDIE(const DICompositeType *Ty); 306 307 protected: 308 ~DwarfUnit(); 309 310 /// Create new static data member DIE. 311 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT); 312 313 /// Look up the source ID for the given file. If none currently exists, 314 /// create a new ID and insert it in the line table. 315 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0; 316 317 /// Emit the common part of the header for this unit. 318 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT); 319 320 private: 321 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy); 322 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy); 323 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy); 324 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, 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. 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 }; 354 355 class DwarfTypeUnit final : public DwarfUnit { 356 uint64_t TypeSignature; 357 const DIE *Ty; 358 DwarfCompileUnit &CU; 359 MCDwarfDwoLineTable *SplitLineTable; 360 bool UsedLineTable = false; 361 362 unsigned getOrCreateSourceID(const DIFile *File) override; 363 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override; 364 bool isDwoUnit() const override; 365 366 public: 367 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW, 368 DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr); 369 370 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; } 371 void setType(const DIE *Ty) { this->Ty = Ty; } 372 373 /// Emit the header for this unit, not including the initial length field. 374 void emitHeader(bool UseOffsets) override; 375 unsigned getHeaderSize() const override { 376 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature 377 sizeof(uint32_t); // Type DIE Offset 378 } 379 void addGlobalName(StringRef Name, const DIE &Die, 380 const DIScope *Context) override; 381 void addGlobalType(const DIType *Ty, const DIE &Die, 382 const DIScope *Context) override; 383 DwarfCompileUnit &getCU() override { return CU; } 384 }; 385 } // end llvm namespace 386 #endif 387