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 "llvm/Target/TargetMachine.h" 22 #include <string> 23 24 namespace llvm { 25 26 class ConstantFP; 27 class ConstantInt; 28 class DbgVariable; 29 class DwarfCompileUnit; 30 class MachineOperand; 31 class MCDwarfDwoLineTable; 32 class MCSymbol; 33 34 //===----------------------------------------------------------------------===// 35 /// This dwarf writer support class manages information associated with a 36 /// source file. 37 class DwarfUnit : public DIEUnit { 38 protected: 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 /// Emitted at the end of the CU and used to compute the CU Length field. 49 MCSymbol *EndLabel = nullptr; 50 51 // Holders for some common dwarf information. 52 DwarfDebug *DD; 53 DwarfFile *DU; 54 55 /// An anonymous type for index type. Owned by DIEUnit. 56 DIE *IndexTyDie; 57 58 /// Tracks the mapping of unit level debug information variables to debug 59 /// information entries. 60 DenseMap<const MDNode *, DIE *> MDNodeToDieMap; 61 62 /// A list of all the DIEBlocks in use. 63 std::vector<DIEBlock *> DIEBlocks; 64 65 /// A list of all the DIELocs in use. 66 std::vector<DIELoc *> DIELocs; 67 68 /// This map is used to keep track of subprogram DIEs that need 69 /// DW_AT_containing_type attribute. This attribute points to a DIE that 70 /// corresponds to the MDNode mapped with the subprogram DIE. 71 DenseMap<DIE *, const DINode *> ContainingTypeMap; 72 73 DwarfUnit(dwarf::Tag, const DICompileUnit *Node, AsmPrinter *A, DwarfDebug *DW, 74 DwarfFile *DWU); 75 76 bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie, bool Minimal); 77 78 bool isShareableAcrossCUs(const DINode *D) const; 79 80 template <typename T> 81 void addAttribute(DIEValueList &Die, dwarf::Attribute Attribute, 82 dwarf::Form Form, T &&Value) { 83 // For strict DWARF mode, only generate attributes available to current 84 // DWARF version. 85 // Attribute 0 is used when emitting form-encoded values in blocks, which 86 // don't have attributes (only forms) so we cannot detect their DWARF 87 // version compatibility here and assume they are compatible. 88 if (Attribute != 0 && Asm->TM.Options.DebugStrictDwarf && 89 DD->getDwarfVersion() < dwarf::AttributeVersion(Attribute)) 90 return; 91 92 Die.addValue(DIEValueAllocator, 93 DIEValue(Attribute, Form, std::forward<T>(Value))); 94 } 95 96 public: 97 // Accessors. 98 AsmPrinter* getAsmPrinter() const { return Asm; } 99 MCSymbol *getEndLabel() const { return EndLabel; } 100 uint16_t getLanguage() const { return CUNode->getSourceLanguage(); } 101 const DICompileUnit *getCUNode() const { return CUNode; } 102 DwarfDebug &getDwarfDebug() const { return *DD; } 103 104 /// Return true if this compile unit has something to write out. 105 bool hasContent() const { return getUnitDie().hasChildren(); } 106 107 /// Get string containing language specific context for a global name. 108 /// 109 /// Walks the metadata parent chain in a language specific manner (using the 110 /// compile unit language) and returns it as a string. This is done at the 111 /// metadata level because DIEs may not currently have been added to the 112 /// parent context and walking the DIEs looking for names is more expensive 113 /// than walking the metadata. 114 std::string getParentContextString(const DIScope *Context) const; 115 116 /// Add a new global name to the compile unit. 117 virtual void addGlobalName(StringRef Name, const DIE &Die, 118 const DIScope *Context) = 0; 119 120 /// Add a new global type to the compile unit. 121 virtual void addGlobalType(const DIType *Ty, const DIE &Die, 122 const DIScope *Context) = 0; 123 124 /// Returns the DIE map slot for the specified debug variable. 125 /// 126 /// We delegate the request to DwarfDebug when the MDNode can be part of the 127 /// type system, since DIEs for the type system can be shared across CUs and 128 /// the mappings are kept in DwarfDebug. 129 DIE *getDIE(const DINode *D) const; 130 131 /// Returns a fresh newly allocated DIELoc. 132 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; } 133 134 /// Insert DIE into the map. 135 /// 136 /// We delegate the request to DwarfDebug when the MDNode can be part of the 137 /// type system, since DIEs for the type system can be shared across CUs and 138 /// the mappings are kept in DwarfDebug. 139 void insertDIE(const DINode *Desc, DIE *D); 140 141 void insertDIE(DIE *D); 142 143 /// Add a flag that is true to the DIE. 144 void addFlag(DIE &Die, dwarf::Attribute Attribute); 145 146 /// Add an unsigned integer attribute data and value. 147 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute, 148 Optional<dwarf::Form> Form, uint64_t Integer); 149 150 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer); 151 152 /// Add an signed integer attribute data and value. 153 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute, 154 Optional<dwarf::Form> Form, int64_t Integer); 155 156 void addSInt(DIELoc &Die, Optional<dwarf::Form> Form, int64_t Integer); 157 158 /// Add a string attribute data and value. 159 /// 160 /// We always emit a reference to the string pool instead of immediate 161 /// strings so that DIEs have more predictable sizes. In the case of split 162 /// dwarf we emit an index into another table which gets us the static offset 163 /// into the string table. 164 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str); 165 166 /// Add a Dwarf label attribute data and value. 167 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form, 168 const MCSymbol *Label); 169 170 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label); 171 172 /// Add an offset into a section attribute data and value. 173 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer); 174 175 /// Add a dwarf op address data and value using the form given and an 176 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index. 177 void addOpAddress(DIELoc &Die, const MCSymbol *Sym); 178 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label); 179 180 /// Add a label delta attribute data and value. 181 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute, 182 const MCSymbol *Hi, const MCSymbol *Lo); 183 184 /// Add a DIE attribute data and value. 185 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry); 186 187 /// Add a DIE attribute data and value. 188 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry); 189 190 /// Add a type's DW_AT_signature and set the declaration flag. 191 void addDIETypeSignature(DIE &Die, uint64_t Signature); 192 193 /// Add block data. 194 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc); 195 196 /// Add block data. 197 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block); 198 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form, 199 DIEBlock *Block); 200 201 /// Add location information to specified debug information entry. 202 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File); 203 void addSourceLine(DIE &Die, const DILocalVariable *V); 204 void addSourceLine(DIE &Die, const DIGlobalVariable *G); 205 void addSourceLine(DIE &Die, const DISubprogram *SP); 206 void addSourceLine(DIE &Die, const DILabel *L); 207 void addSourceLine(DIE &Die, const DIType *Ty); 208 void addSourceLine(DIE &Die, const DIObjCProperty *Ty); 209 210 /// Add constant value entry in variable DIE. 211 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty); 212 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty); 213 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned); 214 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty); 215 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val); 216 217 /// Add constant value entry in variable DIE. 218 void addConstantFPValue(DIE &Die, const ConstantFP *CFP); 219 220 /// Add a linkage name, if it isn't empty. 221 void addLinkageName(DIE &Die, StringRef LinkageName); 222 223 /// Add template parameters in buffer. 224 void addTemplateParams(DIE &Buffer, DINodeArray TParams); 225 226 /// Add thrown types. 227 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); 228 229 /// Add the accessibility attribute. 230 void addAccess(DIE &Die, DINode::DIFlags Flags); 231 232 /// Add a new type attribute to the specified entity. 233 /// 234 /// This takes and attribute parameter because DW_AT_friend attributes are 235 /// also type references. 236 void addType(DIE &Entity, const DIType *Ty, 237 dwarf::Attribute Attribute = dwarf::DW_AT_type); 238 239 DIE *getOrCreateNameSpace(const DINamespace *NS); 240 DIE *getOrCreateModule(const DIModule *M); 241 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false); 242 243 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie, 244 bool SkipSPAttributes = false); 245 246 /// Creates type DIE with specific context. 247 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty); 248 249 /// Find existing DIE or create new DIE for the given type. 250 DIE *getOrCreateTypeDIE(const MDNode *TyNode); 251 252 /// Get context owner's DIE. 253 DIE *getOrCreateContextDIE(const DIScope *Context); 254 255 /// Construct DIEs for types that contain vtables. 256 void constructContainingTypeDIEs(); 257 258 /// Construct function argument DIEs. 259 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args); 260 261 /// Create a DIE with the given Tag, add the DIE to its parent, and 262 /// call insertDIE if MD is not null. 263 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr); 264 265 bool useSegmentedStringOffsetsTable() const { 266 return DD->useSegmentedStringOffsetsTable(); 267 } 268 269 /// Compute the size of a header for this unit, not including the initial 270 /// length field. 271 virtual unsigned getHeaderSize() const { 272 return sizeof(int16_t) + // DWARF version number 273 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section 274 sizeof(int8_t) + // Pointer Size (in bytes) 275 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t) 276 : 0); // DWARF v5 unit type 277 } 278 279 /// Emit the header for this unit, not including the initial length field. 280 virtual void emitHeader(bool UseOffsets) = 0; 281 282 /// Add the DW_AT_str_offsets_base attribute to the unit DIE. 283 void addStringOffsetsStart(); 284 285 /// Add the DW_AT_rnglists_base attribute to the unit DIE. 286 void addRnglistsBase(); 287 288 virtual DwarfCompileUnit &getCU() = 0; 289 290 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy); 291 292 /// addSectionDelta - Add a label delta attribute data and value. 293 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi, 294 const MCSymbol *Lo); 295 296 /// Add a Dwarf section label attribute data and value. 297 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute, 298 const MCSymbol *Label, const MCSymbol *Sec); 299 300 /// Add DW_TAG_LLVM_annotation. 301 void addAnnotation(DIE &Buffer, DINodeArray Annotations); 302 303 /// Get context owner's DIE. 304 DIE *createTypeDIE(const DICompositeType *Ty); 305 306 protected: 307 ~DwarfUnit(); 308 309 /// Create new static data member DIE. 310 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT); 311 312 /// Look up the source ID for the given file. If none currently exists, 313 /// create a new ID and insert it in the line table. 314 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0; 315 316 /// Emit the common part of the header for this unit. 317 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT); 318 319 private: 320 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy); 321 void constructTypeDIE(DIE &Buffer, const DIStringType *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 constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR, 326 DIE *IndexTy); 327 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy); 328 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy); 329 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT); 330 void constructTemplateTypeParameterDIE(DIE &Buffer, 331 const DITemplateTypeParameter *TP); 332 void constructTemplateValueParameterDIE(DIE &Buffer, 333 const DITemplateValueParameter *TVP); 334 335 /// Return the default lower bound for an array. 336 /// 337 /// If the DWARF version doesn't handle the language, return -1. 338 int64_t getDefaultLowerBound() const; 339 340 /// Get an anonymous type for index type. 341 DIE *getIndexTyDie(); 342 343 /// Set D as anonymous type for index which can be reused later. 344 void setIndexTyDie(DIE *D) { IndexTyDie = D; } 345 346 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0; 347 348 /// If this is a named finished type then include it in the list of types for 349 /// the accelerator tables. 350 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty, 351 const DIE &TyDIE); 352 353 virtual bool isDwoUnit() const = 0; 354 const MCSymbol *getCrossSectionRelativeBaseAddress() const override; 355 }; 356 357 class DwarfTypeUnit final : public DwarfUnit { 358 uint64_t TypeSignature; 359 const DIE *Ty; 360 DwarfCompileUnit &CU; 361 MCDwarfDwoLineTable *SplitLineTable; 362 bool UsedLineTable = false; 363 364 unsigned getOrCreateSourceID(const DIFile *File) override; 365 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override; 366 bool isDwoUnit() const override; 367 368 public: 369 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW, 370 DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr); 371 372 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; } 373 void setType(const DIE *Ty) { this->Ty = Ty; } 374 375 /// Emit the header for this unit, not including the initial length field. 376 void emitHeader(bool UseOffsets) override; 377 unsigned getHeaderSize() const override { 378 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature 379 Asm->getDwarfOffsetByteSize(); // Type DIE Offset 380 } 381 void addGlobalName(StringRef Name, const DIE &Die, 382 const DIScope *Context) override; 383 void addGlobalType(const DIType *Ty, const DIE &Die, 384 const DIScope *Context) override; 385 DwarfCompileUnit &getCU() override { return CU; } 386 }; 387 } // end llvm namespace 388 #endif 389