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