llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

   1 //===- llvm/CodeGen/DwarfCompileUnit.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_DWARFCOMPILEUNIT_H
  14 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H
  15
  16 #include "DwarfDebug.h"
  17 #include "DwarfUnit.h"
  18 #include "llvm/ADT/ArrayRef.h"
  19 #include "llvm/ADT/DenseMap.h"
  20 #include "llvm/ADT/SmallVector.h"
  21 #include "llvm/ADT/StringMap.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/BinaryFormat/Dwarf.h"
  24 #include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
  25 #include "llvm/CodeGen/LexicalScopes.h"
  26 #include "llvm/IR/DebugInfoMetadata.h"
  27 #include "llvm/Support/Casting.h"
  28 #include <cassert>
  29 #include <cstdint>
  30 #include <memory>
  31
  32 namespace llvm {
  33
  34 class AsmPrinter;
  35 class DIE;
  36 class DIELoc;
  37 class DIEValueList;
  38 class DwarfFile;
  39 class GlobalVariable;
  40 class MCExpr;
  41 class MCSymbol;
  42 class MDNode;
  43
  44 enum class UnitKind { Skeleton, Full };
  45
  46 class DwarfCompileUnit final : public DwarfUnit {
  47   /// A numeric ID unique among all CUs in the module
  48   unsigned UniqueID;
  49   bool HasRangeLists = false;
  50
  51   /// The start of the unit line section, this is also
  52   /// reused in appyStmtList.
  53   MCSymbol *LineTableStartSym;
  54
  55   /// Skeleton unit associated with this unit.
  56   DwarfCompileUnit *Skeleton = nullptr;
  57
  58   /// The start of the unit within its section.
  59   MCSymbol *LabelBegin = nullptr;
  60
  61   /// The start of the unit macro info within macro section.
  62   MCSymbol *MacroLabelBegin;
  63
  64   using ImportedEntityList = SmallVector<const MDNode *, 8>;
  65   using ImportedEntityMap = DenseMap<const MDNode *, ImportedEntityList>;
  66
  67   ImportedEntityMap ImportedEntities;
  68
  69   /// GlobalNames - A map of globally visible named entities for this unit.
  70   StringMap<const DIE *> GlobalNames;
  71
  72   /// GlobalTypes - A map of globally visible types for this unit.
  73   StringMap<const DIE *> GlobalTypes;
  74
  75   // List of ranges for a given compile unit.
  76   SmallVector<RangeSpan, 2> CURanges;
  77
  78   // The base address of this unit, if any. Used for relative references in
  79   // ranges/locs.
  80   const MCSymbol *BaseAddress = nullptr;
  81
  82   DenseMap<const MDNode *, DIE *> AbstractSPDies;
  83   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
  84
  85   /// DWO ID for correlating skeleton and split units.
  86   uint64_t DWOId = 0;
  87
  88   const DIFile *LastFile = nullptr;
  89   unsigned LastFileID;
  90
  91   /// Construct a DIE for the given DbgVariable without initializing the
  92   /// DbgVariable's DIE reference.
  93   DIE *constructVariableDIEImpl(const DbgVariable &DV, bool Abstract);
  94
  95   bool isDwoUnit() const override;
  96
  97   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
  98     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
  99       return AbstractSPDies;
 100     return DU->getAbstractSPDies();
 101   }
 102
 103   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
 104     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
 105       return AbstractEntities;
 106     return DU->getAbstractEntities();
 107   }
 108
 109   void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
 110
 111 public:
 112   DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
 113                    DwarfDebug *DW, DwarfFile *DWU,
 114                    UnitKind Kind = UnitKind::Full);
 115
 116   bool hasRangeLists() const { return HasRangeLists; }
 117   unsigned getUniqueID() const { return UniqueID; }
 118
 119   DwarfCompileUnit *getSkeleton() const {
 120     return Skeleton;
 121   }
 122
 123   bool includeMinimalInlineScopes() const;
 124
 125   void initStmtList();
 126
 127   /// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
 128   void applyStmtList(DIE &D);
 129
 130   /// Get line table start symbol for this unit.
 131   MCSymbol *getLineTableStartSym() const { return LineTableStartSym; }
 132
 133   /// A pair of GlobalVariable and DIExpression.
 134   struct GlobalExpr {
 135     const GlobalVariable *Var;
 136     const DIExpression *Expr;
 137   };
 138
 139   struct BaseTypeRef {
 140     BaseTypeRef(unsigned BitSize, dwarf::TypeKind Encoding) :
 141       BitSize(BitSize), Encoding(Encoding) {}
 142     unsigned BitSize;
 143     dwarf::TypeKind Encoding;
 144     DIE *Die = nullptr;
 145   };
 146
 147   std::vector<BaseTypeRef> ExprRefedBaseTypes;
 148
 149   /// Get or create global variable DIE.
 150   DIE *
 151   getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV,
 152                                ArrayRef<GlobalExpr> GlobalExprs);
 153
 154   DIE *getOrCreateCommonBlock(const DICommonBlock *CB,
 155                               ArrayRef<GlobalExpr> GlobalExprs);
 156
 157   void addLocationAttribute(DIE *ToDIE, const DIGlobalVariable *GV,
 158                             ArrayRef<GlobalExpr> GlobalExprs);
 159
 160   /// addLabelAddress - Add a dwarf label attribute data and value using
 161   /// either DW_FORM_addr or DW_FORM_GNU_addr_index.
 162   void addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
 163                        const MCSymbol *Label);
 164
 165   /// addLocalLabelAddress - Add a dwarf label attribute data and value using
 166   /// DW_FORM_addr only.
 167   void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
 168                             const MCSymbol *Label);
 169
 170   DwarfCompileUnit &getCU() override { return *this; }
 171
 172   unsigned getOrCreateSourceID(const DIFile *File) override;
 173
 174   void addImportedEntity(const DIImportedEntity* IE) {
 175     DIScope *Scope = IE->getScope();
 176     assert(Scope && "Invalid Scope encoding!");
 177     if (!isa<DILocalScope>(Scope))
 178       // No need to add imported enities that are not local declaration.
 179       return;
 180
 181     auto *LocalScope = cast<DILocalScope>(Scope)->getNonLexicalBlockFileScope();
 182     ImportedEntities[LocalScope].push_back(IE);
 183   }
 184
 185   /// addRange - Add an address range to the list of ranges for this unit.
 186   void addRange(RangeSpan Range);
 187
 188   void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
 189
 190   /// Find DIE for the given subprogram and attach appropriate
 191   /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
 192   /// variables in this scope then create and insert DIEs for these
 193   /// variables.
 194   DIE &updateSubprogramScopeDIE(const DISubprogram *SP);
 195
 196   void constructScopeDIE(LexicalScope *Scope, DIE &ParentScopeDIE);
 197
 198   /// A helper function to construct a RangeSpanList for a given
 199   /// lexical scope.
 200   void addScopeRangeList(DIE &ScopeDIE, SmallVector<RangeSpan, 2> Range);
 201
 202   void attachRangesOrLowHighPC(DIE &D, SmallVector<RangeSpan, 2> Ranges);
 203
 204   void attachRangesOrLowHighPC(DIE &D,
 205                                const SmallVectorImpl<InsnRange> &Ranges);
 206
 207   /// This scope represents inlined body of a function. Construct
 208   /// DIE to represent this concrete inlined copy of the function.
 209   DIE *constructInlinedScopeDIE(LexicalScope *Scope);
 210
 211   /// Construct new DW_TAG_lexical_block for this scope and
 212   /// attach DW_AT_low_pc/DW_AT_high_pc labels.
 213   DIE *constructLexicalScopeDIE(LexicalScope *Scope);
 214
 215   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
 216   DIE *constructVariableDIE(DbgVariable &DV, bool Abstract = false);
 217
 218   DIE *constructVariableDIE(DbgVariable &DV, const LexicalScope &Scope,
 219                             DIE *&ObjectPointer);
 220
 221   /// Construct a DIE for the given DbgLabel.
 222   DIE *constructLabelDIE(DbgLabel &DL, const LexicalScope &Scope);
 223
 224   void createBaseTypeDIEs();
 225
 226   /// Construct a DIE for this subprogram scope.
 227   DIE &constructSubprogramScopeDIE(const DISubprogram *Sub,
 228                                    LexicalScope *Scope);
 229
 230   DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
 231
 232   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 233
 234   /// Whether to use the GNU analog for a DWARF5 tag, attribute, or location
 235   /// atom. Only applicable when emitting otherwise DWARF4-compliant debug info.
 236   bool useGNUAnalogForDwarf5Feature() const;
 237
 238   /// This takes a DWARF 5 tag and returns it or a GNU analog.
 239   dwarf::Tag getDwarf5OrGNUTag(dwarf::Tag Tag) const;
 240
 241   /// This takes a DWARF 5 attribute and returns it or a GNU analog.
 242   dwarf::Attribute getDwarf5OrGNUAttr(dwarf::Attribute Attr) const;
 243
 244   /// This takes a DWARF 5 location atom and either returns it or a GNU analog.
 245   dwarf::LocationAtom getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const;
 246
 247   /// Construct a call site entry DIE describing a call within \p Scope to a
 248   /// callee described by \p CalleeSP.
 249   /// \p IsTail specifies whether the call is a tail call.
 250   /// \p PCAddr points to the PC value after the call instruction.
 251   /// \p CallAddr points to the PC value at the call instruction (or is null).
 252   /// \p CallReg is a register location for an indirect call. For direct calls
 253   /// the \p CallReg is set to 0.
 254   DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
 255                                  bool IsTail, const MCSymbol *PCAddr,
 256                                  const MCSymbol *CallAddr, unsigned CallReg);
 257   /// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
 258   /// were collected by the \ref collectCallSiteParameters.
 259   /// Note: The order of parameters does not matter, since debuggers recognize
 260   ///       call site parameters by the DW_AT_location attribute.
 261   void constructCallSiteParmEntryDIEs(DIE &CallSiteDIE,
 262                                       SmallVector<DbgCallSiteParam, 4> &Params);
 263
 264   /// Construct import_module DIE.
 265   DIE *constructImportedEntityDIE(const DIImportedEntity *Module);
 266
 267   void finishSubprogramDefinition(const DISubprogram *SP);
 268   void finishEntityDefinition(const DbgEntity *Entity);
 269
 270   /// Find abstract variable associated with Var.
 271   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
 272   DbgEntity *getExistingAbstractEntity(const DINode *Node);
 273   void createAbstractEntity(const DINode *Node, LexicalScope *Scope);
 274
 275   /// Set the skeleton unit associated with this unit.
 276   void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
 277
 278   unsigned getHeaderSize() const override {
 279     // DWARF v5 added the DWO ID to the header for split/skeleton units.
 280     unsigned DWOIdSize =
 281         DD->getDwarfVersion() >= 5 && DD->useSplitDwarf() ? sizeof(uint64_t)
 282                                                           : 0;
 283     return DwarfUnit::getHeaderSize() + DWOIdSize;
 284   }
 285   unsigned getLength() {
 286     return Asm->getUnitLengthFieldByteSize() + // Length field
 287            getHeaderSize() + getUnitDie().getSize();
 288   }
 289
 290   void emitHeader(bool UseOffsets) override;
 291
 292   /// Add the DW_AT_addr_base attribute to the unit DIE.
 293   void addAddrTableBase();
 294
 295   MCSymbol *getLabelBegin() const {
 296     assert(LabelBegin && "LabelBegin is not initialized");
 297     return LabelBegin;
 298   }
 299
 300   MCSymbol *getMacroLabelBegin() const {
 301     return MacroLabelBegin;
 302   }
 303
 304   /// Add a new global name to the compile unit.
 305   void addGlobalName(StringRef Name, const DIE &Die,
 306                      const DIScope *Context) override;
 307
 308   /// Add a new global name present in a type unit to this compile unit.
 309   void addGlobalNameForTypeUnit(StringRef Name, const DIScope *Context);
 310
 311   /// Add a new global type to the compile unit.
 312   void addGlobalType(const DIType *Ty, const DIE &Die,
 313                      const DIScope *Context) override;
 314
 315   /// Add a new global type present in a type unit to this compile unit.
 316   void addGlobalTypeUnitType(const DIType *Ty, const DIScope *Context);
 317
 318   const StringMap<const DIE *> &getGlobalNames() const { return GlobalNames; }
 319   const StringMap<const DIE *> &getGlobalTypes() const { return GlobalTypes; }
 320
 321   /// Add DW_AT_location attribute for a DbgVariable based on provided
 322   /// MachineLocation.
 323   void addVariableAddress(const DbgVariable &DV, DIE &Die,
 324                           MachineLocation Location);
 325   /// Add an address attribute to a die based on the location provided.
 326   void addAddress(DIE &Die, dwarf::Attribute Attribute,
 327                   const MachineLocation &Location);
 328
 329   /// Start with the address based on the location provided, and generate the
 330   /// DWARF information necessary to find the actual variable (navigating the
 331   /// extra location information encoded in the type) based on the starting
 332   /// location.  Add the DWARF information to the die.
 333   void addComplexAddress(const DbgVariable &DV, DIE &Die,
 334                          dwarf::Attribute Attribute,
 335                          const MachineLocation &Location);
 336
 337   /// Add a Dwarf loclistptr attribute data and value.
 338   void addLocationList(DIE &Die, dwarf::Attribute Attribute, unsigned Index);
 339   void applyVariableAttributes(const DbgVariable &Var, DIE &VariableDie);
 340
 341   /// Add a Dwarf expression attribute data and value.
 342   void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
 343
 344   void applySubprogramAttributesToDefinition(const DISubprogram *SP,
 345                                              DIE &SPDie);
 346
 347   void applyLabelAttributes(const DbgLabel &Label, DIE &LabelDie);
 348
 349   /// getRanges - Get the list of ranges for this unit.
 350   const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
 351   SmallVector<RangeSpan, 2> takeRanges() { return std::move(CURanges); }
 352
 353   void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
 354   const MCSymbol *getBaseAddress() const { return BaseAddress; }
 355
 356   uint64_t getDWOId() const { return DWOId; }
 357   void setDWOId(uint64_t DwoId) { DWOId = DwoId; }
 358
 359   bool hasDwarfPubSections() const;
 360
 361   void addBaseTypeRef(DIEValueList &Die, int64_t Idx);
 362 };
 363
 364 } // end namespace llvm
 365
 366 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H