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