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/DIE.h"
  26 #include "llvm/CodeGen/LexicalScopes.h"
  27 #include "llvm/IR/DebugInfoMetadata.h"
  28 #include "llvm/Support/Casting.h"
  29 #include <algorithm>
  30 #include <cassert>
  31 #include <cstdint>
  32 #include <memory>
  33
  34 namespace llvm {
  35
  36 class AsmPrinter;
  37 class DwarfFile;
  38 class GlobalVariable;
  39 class MCExpr;
  40 class MCSymbol;
  41 class MDNode;
  42
  43 class DwarfCompileUnit final : public DwarfUnit {
  44   /// A numeric ID unique among all CUs in the module
  45   unsigned UniqueID;
  46   bool HasRangeLists = false;
  47
  48   /// The attribute index of DW_AT_stmt_list in the compile unit DIE, avoiding
  49   /// the need to search for it in applyStmtList.
  50   DIE::value_iterator StmtListValue;
  51
  52   /// Skeleton unit associated with this unit.
  53   DwarfCompileUnit *Skeleton = nullptr;
  54
  55   /// The start of the unit within its section.
  56   MCSymbol *LabelBegin;
  57
  58   /// The start of the unit macro info within macro section.
  59   MCSymbol *MacroLabelBegin;
  60
  61   using ImportedEntityList = SmallVector<const MDNode *, 8>;
  62   using ImportedEntityMap = DenseMap<const MDNode *, ImportedEntityList>;
  63
  64   ImportedEntityMap ImportedEntities;
  65
  66   /// GlobalNames - A map of globally visible named entities for this unit.
  67   StringMap<const DIE *> GlobalNames;
  68
  69   /// GlobalTypes - A map of globally visible types for this unit.
  70   StringMap<const DIE *> GlobalTypes;
  71
  72   // List of ranges for a given compile unit.
  73   SmallVector<RangeSpan, 2> CURanges;
  74
  75   // The base address of this unit, if any. Used for relative references in
  76   // ranges/locs.
  77   const MCSymbol *BaseAddress = nullptr;
  78
  79   DenseMap<const MDNode *, DIE *> AbstractSPDies;
  80   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
  81
  82   /// DWO ID for correlating skeleton and split units.
  83   uint64_t DWOId = 0;
  84
  85   /// Construct a DIE for the given DbgVariable without initializing the
  86   /// DbgVariable's DIE reference.
  87   DIE *constructVariableDIEImpl(const DbgVariable &DV, bool Abstract);
  88
  89   bool isDwoUnit() const override;
  90
  91   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
  92     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
  93       return AbstractSPDies;
  94     return DU->getAbstractSPDies();
  95   }
  96
  97   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
  98     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
  99       return AbstractEntities;
 100     return DU->getAbstractEntities();
 101   }
 102
 103   void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
 104
 105 public:
 106   DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
 107                    DwarfDebug *DW, DwarfFile *DWU);
 108
 109   bool hasRangeLists() const { return HasRangeLists; }
 110   unsigned getUniqueID() const { return UniqueID; }
 111
 112   DwarfCompileUnit *getSkeleton() const {
 113     return Skeleton;
 114   }
 115
 116   bool includeMinimalInlineScopes() const;
 117
 118   void initStmtList();
 119
 120   /// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
 121   void applyStmtList(DIE &D);
 122
 123   /// A pair of GlobalVariable and DIExpression.
 124   struct GlobalExpr {
 125     const GlobalVariable *Var;
 126     const DIExpression *Expr;
 127   };
 128
 129   struct BaseTypeRef {
 130     BaseTypeRef(unsigned BitSize, dwarf::TypeKind Encoding) :
 131       BitSize(BitSize), Encoding(Encoding) {}
 132     unsigned BitSize;
 133     dwarf::TypeKind Encoding;
 134     DIE *Die = nullptr;
 135   };
 136
 137   std::vector<BaseTypeRef> ExprRefedBaseTypes;
 138
 139   /// Get or create global variable DIE.
 140   DIE *
 141   getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV,
 142                                ArrayRef<GlobalExpr> GlobalExprs);
 143
 144   DIE *getOrCreateCommonBlock(const DICommonBlock *CB,
 145                               ArrayRef<GlobalExpr> GlobalExprs);
 146
 147   void addLocationAttribute(DIE *ToDIE, const DIGlobalVariable *GV,
 148                             ArrayRef<GlobalExpr> GlobalExprs);
 149
 150   /// addLabelAddress - Add a dwarf label attribute data and value using
 151   /// either DW_FORM_addr or DW_FORM_GNU_addr_index.
 152   void addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
 153                        const MCSymbol *Label);
 154
 155   /// addLocalLabelAddress - Add a dwarf label attribute data and value using
 156   /// DW_FORM_addr only.
 157   void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
 158                             const MCSymbol *Label);
 159
 160   DwarfCompileUnit &getCU() override { return *this; }
 161
 162   unsigned getOrCreateSourceID(const DIFile *File) override;
 163
 164   void addImportedEntity(const DIImportedEntity* IE) {
 165     DIScope *Scope = IE->getScope();
 166     assert(Scope && "Invalid Scope encoding!");
 167     if (!isa<DILocalScope>(Scope))
 168       // No need to add imported enities that are not local declaration.
 169       return;
 170
 171     auto *LocalScope = cast<DILocalScope>(Scope)->getNonLexicalBlockFileScope();
 172     ImportedEntities[LocalScope].push_back(IE);
 173   }
 174
 175   /// addRange - Add an address range to the list of ranges for this unit.
 176   void addRange(RangeSpan Range);
 177
 178   void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
 179
 180   /// Find DIE for the given subprogram and attach appropriate
 181   /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
 182   /// variables in this scope then create and insert DIEs for these
 183   /// variables.
 184   DIE &updateSubprogramScopeDIE(const DISubprogram *SP);
 185
 186   void constructScopeDIE(LexicalScope *Scope,
 187                          SmallVectorImpl<DIE *> &FinalChildren);
 188
 189   /// A helper function to construct a RangeSpanList for a given
 190   /// lexical scope.
 191   void addScopeRangeList(DIE &ScopeDIE, SmallVector<RangeSpan, 2> Range);
 192
 193   void attachRangesOrLowHighPC(DIE &D, SmallVector<RangeSpan, 2> Ranges);
 194
 195   void attachRangesOrLowHighPC(DIE &D,
 196                                const SmallVectorImpl<InsnRange> &Ranges);
 197
 198   /// This scope represents inlined body of a function. Construct
 199   /// DIE to represent this concrete inlined copy of the function.
 200   DIE *constructInlinedScopeDIE(LexicalScope *Scope);
 201
 202   /// Construct new DW_TAG_lexical_block for this scope and
 203   /// attach DW_AT_low_pc/DW_AT_high_pc labels.
 204   DIE *constructLexicalScopeDIE(LexicalScope *Scope);
 205
 206   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
 207   DIE *constructVariableDIE(DbgVariable &DV, bool Abstract = false);
 208
 209   DIE *constructVariableDIE(DbgVariable &DV, const LexicalScope &Scope,
 210                             DIE *&ObjectPointer);
 211
 212   /// Construct a DIE for the given DbgLabel.
 213   DIE *constructLabelDIE(DbgLabel &DL, const LexicalScope &Scope);
 214
 215   /// A helper function to create children of a Scope DIE.
 216   DIE *createScopeChildrenDIE(LexicalScope *Scope,
 217                               SmallVectorImpl<DIE *> &Children,
 218                               bool *HasNonScopeChildren = nullptr);
 219
 220   void createBaseTypeDIEs();
 221
 222   /// Construct a DIE for this subprogram scope.
 223   DIE &constructSubprogramScopeDIE(const DISubprogram *Sub,
 224                                    LexicalScope *Scope);
 225
 226   DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
 227
 228   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 229
 230   /// This takes a DWARF 5 tag and returns it or a GNU analog.
 231   dwarf::Tag getDwarf5OrGNUTag(dwarf::Tag Tag) const;
 232
 233   /// This takes a DWARF 5 attribute and returns it or a GNU analog.
 234   dwarf::Attribute getDwarf5OrGNUAttr(dwarf::Attribute Attr) const;
 235
 236   /// This takes a DWARF 5 location atom and either returns it or a GNU analog.
 237   dwarf::LocationAtom getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const;
 238
 239   /// Construct a call site entry DIE describing a call within \p Scope to a
 240   /// callee described by \p CalleeSP.
 241   /// \p IsTail specifies whether the call is a tail call.
 242   /// \p PCAddr (used for GDB + DWARF 4 tuning) points to the PC value after
 243   /// the call instruction.
 244   /// \p PCOffset (used for cases other than GDB + DWARF 4 tuning) must be
 245   /// non-zero for non-tail calls (in the case of non-gdb tuning, since for
 246   /// GDB + DWARF 5 tuning we still generate PC info for tail calls) or be the
 247   /// function-local offset to PC value after the call instruction.
 248   /// \p CallReg is a register location for an indirect call. For direct calls
 249   /// the \p CallReg is set to 0.
 250   DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
 251                                  bool IsTail, const MCSymbol *PCAddr,
 252                                  const MCExpr *PCOffset, unsigned CallReg);
 253   /// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
 254   /// were collected by the \ref collectCallSiteParameters.
 255   /// Note: The order of parameters does not matter, since debuggers recognize
 256   ///       call site parameters by the DW_AT_location attribute.
 257   void constructCallSiteParmEntryDIEs(DIE &CallSiteDIE,
 258                                       SmallVector<DbgCallSiteParam, 4> &Params);
 259
 260   /// Construct import_module DIE.
 261   DIE *constructImportedEntityDIE(const DIImportedEntity *Module);
 262
 263   void finishSubprogramDefinition(const DISubprogram *SP);
 264   void finishEntityDefinition(const DbgEntity *Entity);
 265
 266   /// Find abstract variable associated with Var.
 267   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
 268   DbgEntity *getExistingAbstractEntity(const DINode *Node);
 269   void createAbstractEntity(const DINode *Node, LexicalScope *Scope);
 270
 271   /// Set the skeleton unit associated with this unit.
 272   void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
 273
 274   unsigned getHeaderSize() const override {
 275     // DWARF v5 added the DWO ID to the header for split/skeleton units.
 276     unsigned DWOIdSize =
 277         DD->getDwarfVersion() >= 5 && DD->useSplitDwarf() ? sizeof(uint64_t)
 278                                                           : 0;
 279     return DwarfUnit::getHeaderSize() + DWOIdSize;
 280   }
 281   unsigned getLength() {
 282     return sizeof(uint32_t) + // Length field
 283         getHeaderSize() + getUnitDie().getSize();
 284   }
 285
 286   void emitHeader(bool UseOffsets) override;
 287
 288   /// Add the DW_AT_addr_base attribute to the unit DIE.
 289   void addAddrTableBase();
 290
 291   MCSymbol *getLabelBegin() const {
 292     assert(getSection());
 293     return LabelBegin;
 294   }
 295
 296   MCSymbol *getMacroLabelBegin() const {
 297     return MacroLabelBegin;
 298   }
 299
 300   /// Add a new global name to the compile unit.
 301   void addGlobalName(StringRef Name, const DIE &Die,
 302                      const DIScope *Context) override;
 303
 304   /// Add a new global name present in a type unit to this compile unit.
 305   void addGlobalNameForTypeUnit(StringRef Name, const DIScope *Context);
 306
 307   /// Add a new global type to the compile unit.
 308   void addGlobalType(const DIType *Ty, const DIE &Die,
 309                      const DIScope *Context) override;
 310
 311   /// Add a new global type present in a type unit to this compile unit.
 312   void addGlobalTypeUnitType(const DIType *Ty, const DIScope *Context);
 313
 314   const StringMap<const DIE *> &getGlobalNames() const { return GlobalNames; }
 315   const StringMap<const DIE *> &getGlobalTypes() const { return GlobalTypes; }
 316
 317   /// Add DW_AT_location attribute for a DbgVariable based on provided
 318   /// MachineLocation.
 319   void addVariableAddress(const DbgVariable &DV, DIE &Die,
 320                           MachineLocation Location);
 321   /// Add an address attribute to a die based on the location provided.
 322   void addAddress(DIE &Die, dwarf::Attribute Attribute,
 323                   const MachineLocation &Location);
 324
 325   /// Start with the address based on the location provided, and generate the
 326   /// DWARF information necessary to find the actual variable (navigating the
 327   /// extra location information encoded in the type) based on the starting
 328   /// location.  Add the DWARF information to the die.
 329   void addComplexAddress(const DbgVariable &DV, DIE &Die,
 330                          dwarf::Attribute Attribute,
 331                          const MachineLocation &Location);
 332
 333   /// Add a Dwarf loclistptr attribute data and value.
 334   void addLocationList(DIE &Die, dwarf::Attribute Attribute, unsigned Index);
 335   void applyVariableAttributes(const DbgVariable &Var, DIE &VariableDie);
 336
 337   /// Add a Dwarf expression attribute data and value.
 338   void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
 339
 340   /// Add an attribute containing an address expression to \p Die.
 341   void addAddressExpr(DIE &Die, dwarf::Attribute Attribute, const MCExpr *Expr);
 342
 343   void applySubprogramAttributesToDefinition(const DISubprogram *SP,
 344                                              DIE &SPDie);
 345
 346   void applyLabelAttributes(const DbgLabel &Label, DIE &LabelDie);
 347
 348   /// getRanges - Get the list of ranges for this unit.
 349   const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
 350   SmallVector<RangeSpan, 2> takeRanges() { return std::move(CURanges); }
 351
 352   void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
 353   const MCSymbol *getBaseAddress() const { return BaseAddress; }
 354
 355   uint64_t getDWOId() const { return DWOId; }
 356   void setDWOId(uint64_t DwoId) { DWOId = DwoId; }
 357
 358   bool hasDwarfPubSections() const;
 359
 360   void addBaseTypeRef(DIEValueList &Die, int64_t Idx);
 361 };
 362
 363 } // end namespace llvm
 364
 365 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H