llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h

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