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/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   /// Add a new type attribute to the specified entity.
 220   ///
 221   /// This takes and attribute parameter because DW_AT_friend attributes are
 222   /// also type references.
 223   void addType(DIE &Entity, const DIType *Ty,
 224                dwarf::Attribute Attribute = dwarf::DW_AT_type);
 225
 226   DIE *getOrCreateNameSpace(const DINamespace *NS);
 227   DIE *getOrCreateModule(const DIModule *M);
 228   DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
 229
 230   void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
 231                                  bool SkipSPAttributes = false);
 232
 233   /// Creates type DIE with specific context.
 234   DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
 235
 236   /// Find existing DIE or create new DIE for the given type.
 237   DIE *getOrCreateTypeDIE(const MDNode *TyNode);
 238
 239   /// Get context owner's DIE.
 240   DIE *getOrCreateContextDIE(const DIScope *Context);
 241
 242   /// Construct DIEs for types that contain vtables.
 243   void constructContainingTypeDIEs();
 244
 245   /// Construct function argument DIEs.
 246   void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
 247
 248   /// Create a DIE with the given Tag, add the DIE to its parent, and
 249   /// call insertDIE if MD is not null.
 250   DIE &createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N = nullptr);
 251
 252   bool useSegmentedStringOffsetsTable() const {
 253     return DD->useSegmentedStringOffsetsTable();
 254   }
 255
 256   /// Compute the size of a header for this unit, not including the initial
 257   /// length field.
 258   virtual unsigned getHeaderSize() const {
 259     return sizeof(int16_t) + // DWARF version number
 260            sizeof(int32_t) + // Offset Into Abbrev. Section
 261            sizeof(int8_t) +  // Pointer Size (in bytes)
 262            (DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
 263                                        : 0); // DWARF v5 unit type
 264   }
 265
 266   /// Emit the header for this unit, not including the initial length field.
 267   virtual void emitHeader(bool UseOffsets) = 0;
 268
 269   /// Add the DW_AT_str_offsets_base attribute to the unit DIE.
 270   void addStringOffsetsStart();
 271
 272   /// Add the DW_AT_rnglists_base attribute to the unit DIE.
 273   void addRnglistsBase();
 274
 275   virtual DwarfCompileUnit &getCU() = 0;
 276
 277   void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
 278
 279   /// addSectionDelta - Add a label delta attribute data and value.
 280   DIE::value_iterator addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
 281                                       const MCSymbol *Hi, const MCSymbol *Lo);
 282
 283   /// Add a Dwarf section label attribute data and value.
 284   DIE::value_iterator addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
 285                                       const MCSymbol *Label,
 286                                       const MCSymbol *Sec);
 287
 288   /// If the \p File has an MD5 checksum, return it as an MD5Result
 289   /// allocated in the MCContext.
 290   Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
 291
 292   /// Get context owner's DIE.
 293   DIE *createTypeDIE(const DICompositeType *Ty);
 294
 295 protected:
 296   ~DwarfUnit();
 297
 298   /// Create new static data member DIE.
 299   DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
 300
 301   /// Look up the source ID for the given file. If none currently exists,
 302   /// create a new ID and insert it in the line table.
 303   virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
 304
 305   /// Emit the common part of the header for this unit.
 306   void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
 307
 308 private:
 309   void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
 310   void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
 311   void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
 312   void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);
 313   void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
 314   void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
 315   DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
 316   void constructTemplateTypeParameterDIE(DIE &Buffer,
 317                                          const DITemplateTypeParameter *TP);
 318   void constructTemplateValueParameterDIE(DIE &Buffer,
 319                                           const DITemplateValueParameter *TVP);
 320
 321   /// Return the default lower bound for an array.
 322   ///
 323   /// If the DWARF version doesn't handle the language, return -1.
 324   int64_t getDefaultLowerBound() const;
 325
 326   /// Get an anonymous type for index type.
 327   DIE *getIndexTyDie();
 328
 329   /// Set D as anonymous type for index which can be reused later.
 330   void setIndexTyDie(DIE *D) { IndexTyDie = D; }
 331
 332   virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0;
 333
 334   /// If this is a named finished type then include it in the list of types for
 335   /// the accelerator tables.
 336   void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
 337                                const DIE &TyDIE);
 338
 339   virtual bool isDwoUnit() const = 0;
 340   const MCSymbol *getCrossSectionRelativeBaseAddress() const override;
 341 };
 342
 343 class DwarfTypeUnit final : public DwarfUnit {
 344   uint64_t TypeSignature;
 345   const DIE *Ty;
 346   DwarfCompileUnit &CU;
 347   MCDwarfDwoLineTable *SplitLineTable;
 348   bool UsedLineTable = false;
 349
 350   unsigned getOrCreateSourceID(const DIFile *File) override;
 351   void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
 352   bool isDwoUnit() const override;
 353
 354 public:
 355   DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
 356                 DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr);
 357
 358   void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
 359   void setType(const DIE *Ty) { this->Ty = Ty; }
 360
 361   /// Emit the header for this unit, not including the initial length field.
 362   void emitHeader(bool UseOffsets) override;
 363   unsigned getHeaderSize() const override {
 364     return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
 365            sizeof(uint32_t);                               // Type DIE Offset
 366   }
 367   void addGlobalName(StringRef Name, const DIE &Die,
 368                      const DIScope *Context) override;
 369   void addGlobalType(const DIType *Ty, const DIE &Die,
 370                      const DIScope *Context) override;
 371   DwarfCompileUnit &getCU() override { return CU; }
 372 };
 373 } // end llvm namespace
 374 #endif