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      1 //===--- lib/CodeGen/DIE.h - DWARF Info Entries -----------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Data structures for DWARF info entries.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef CODEGEN_ASMPRINTER_DIE_H__
     15 #define CODEGEN_ASMPRINTER_DIE_H__
     16 
     17 #include "llvm/ADT/FoldingSet.h"
     18 #include "llvm/ADT/SmallVector.h"
     19 #include "llvm/Support/Dwarf.h"
     20 #include <vector>
     21 
     22 namespace llvm {
     23 class AsmPrinter;
     24 class MCExpr;
     25 class MCSymbol;
     26 class raw_ostream;
     27 class DwarfTypeUnit;
     28 
     29 //===--------------------------------------------------------------------===//
     30 /// DIEAbbrevData - Dwarf abbreviation data, describes one attribute of a
     31 /// Dwarf abbreviation.
     32 class DIEAbbrevData {
     33   /// Attribute - Dwarf attribute code.
     34   ///
     35   dwarf::Attribute Attribute;
     36 
     37   /// Form - Dwarf form code.
     38   ///
     39   dwarf::Form Form;
     40 
     41 public:
     42   DIEAbbrevData(dwarf::Attribute A, dwarf::Form F) : Attribute(A), Form(F) {}
     43 
     44   // Accessors.
     45   dwarf::Attribute getAttribute() const { return Attribute; }
     46   dwarf::Form getForm() const { return Form; }
     47 
     48   /// Profile - Used to gather unique data for the abbreviation folding set.
     49   ///
     50   void Profile(FoldingSetNodeID &ID) const;
     51 };
     52 
     53 //===--------------------------------------------------------------------===//
     54 /// DIEAbbrev - Dwarf abbreviation, describes the organization of a debug
     55 /// information object.
     56 class DIEAbbrev : public FoldingSetNode {
     57   /// Unique number for node.
     58   ///
     59   unsigned Number;
     60 
     61   /// Tag - Dwarf tag code.
     62   ///
     63   dwarf::Tag Tag;
     64 
     65   /// Children - Whether or not this node has children.
     66   ///
     67   // This cheats a bit in all of the uses since the values in the standard
     68   // are 0 and 1 for no children and children respectively.
     69   bool Children;
     70 
     71   /// Data - Raw data bytes for abbreviation.
     72   ///
     73   SmallVector<DIEAbbrevData, 12> Data;
     74 
     75 public:
     76   DIEAbbrev(dwarf::Tag T, bool C) : Tag(T), Children(C), Data() {}
     77 
     78   // Accessors.
     79   dwarf::Tag getTag() const { return Tag; }
     80   unsigned getNumber() const { return Number; }
     81   bool hasChildren() const { return Children; }
     82   const SmallVectorImpl<DIEAbbrevData> &getData() const { return Data; }
     83   void setChildrenFlag(bool hasChild) { Children = hasChild; }
     84   void setNumber(unsigned N) { Number = N; }
     85 
     86   /// AddAttribute - Adds another set of attribute information to the
     87   /// abbreviation.
     88   void AddAttribute(dwarf::Attribute Attribute, dwarf::Form Form) {
     89     Data.push_back(DIEAbbrevData(Attribute, Form));
     90   }
     91 
     92   /// Profile - Used to gather unique data for the abbreviation folding set.
     93   ///
     94   void Profile(FoldingSetNodeID &ID) const;
     95 
     96   /// Emit - Print the abbreviation using the specified asm printer.
     97   ///
     98   void Emit(AsmPrinter *AP) const;
     99 
    100 #ifndef NDEBUG
    101   void print(raw_ostream &O);
    102   void dump();
    103 #endif
    104 };
    105 
    106 //===--------------------------------------------------------------------===//
    107 /// DIE - A structured debug information entry.  Has an abbreviation which
    108 /// describes its organization.
    109 class DIEValue;
    110 
    111 class DIE {
    112 protected:
    113   /// Offset - Offset in debug info section.
    114   ///
    115   unsigned Offset;
    116 
    117   /// Size - Size of instance + children.
    118   ///
    119   unsigned Size;
    120 
    121   /// Abbrev - Buffer for constructing abbreviation.
    122   ///
    123   DIEAbbrev Abbrev;
    124 
    125   /// Children DIEs.
    126   ///
    127   // This can't be a vector<DIE> because pointer validity is requirent for the
    128   // Parent pointer and DIEEntry.
    129   // It can't be a list<DIE> because some clients need pointer validity before
    130   // the object has been added to any child list
    131   // (eg: DwarfUnit::constructVariableDIE). These aren't insurmountable, but may
    132   // be more convoluted than beneficial.
    133   std::vector<std::unique_ptr<DIE>> Children;
    134 
    135   DIE *Parent;
    136 
    137   /// Attribute values.
    138   ///
    139   SmallVector<DIEValue *, 12> Values;
    140 
    141 protected:
    142   DIE()
    143       : Offset(0), Size(0), Abbrev((dwarf::Tag)0, dwarf::DW_CHILDREN_no),
    144         Parent(nullptr) {}
    145 
    146 public:
    147   explicit DIE(dwarf::Tag Tag)
    148       : Offset(0), Size(0), Abbrev((dwarf::Tag)Tag, dwarf::DW_CHILDREN_no),
    149         Parent(nullptr) {}
    150 
    151   // Accessors.
    152   DIEAbbrev &getAbbrev() { return Abbrev; }
    153   const DIEAbbrev &getAbbrev() const { return Abbrev; }
    154   unsigned getAbbrevNumber() const { return Abbrev.getNumber(); }
    155   dwarf::Tag getTag() const { return Abbrev.getTag(); }
    156   unsigned getOffset() const { return Offset; }
    157   unsigned getSize() const { return Size; }
    158   const std::vector<std::unique_ptr<DIE>> &getChildren() const {
    159     return Children;
    160   }
    161   const SmallVectorImpl<DIEValue *> &getValues() const { return Values; }
    162   DIE *getParent() const { return Parent; }
    163   /// Climb up the parent chain to get the compile or type unit DIE this DIE
    164   /// belongs to.
    165   const DIE *getUnit() const;
    166   /// Similar to getUnit, returns null when DIE is not added to an
    167   /// owner yet.
    168   const DIE *getUnitOrNull() const;
    169   void setOffset(unsigned O) { Offset = O; }
    170   void setSize(unsigned S) { Size = S; }
    171 
    172   /// addValue - Add a value and attributes to a DIE.
    173   ///
    174   void addValue(dwarf::Attribute Attribute, dwarf::Form Form, DIEValue *Value) {
    175     Abbrev.AddAttribute(Attribute, Form);
    176     Values.push_back(Value);
    177   }
    178 
    179   /// addChild - Add a child to the DIE.
    180   ///
    181   void addChild(std::unique_ptr<DIE> Child) {
    182     assert(!Child->getParent());
    183     Abbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
    184     Child->Parent = this;
    185     Children.push_back(std::move(Child));
    186   }
    187 
    188   /// findAttribute - Find a value in the DIE with the attribute given,
    189   /// returns NULL if no such attribute exists.
    190   DIEValue *findAttribute(dwarf::Attribute Attribute) const;
    191 
    192 #ifndef NDEBUG
    193   void print(raw_ostream &O, unsigned IndentCount = 0) const;
    194   void dump();
    195 #endif
    196 };
    197 
    198 //===--------------------------------------------------------------------===//
    199 /// DIEValue - A debug information entry value. Some of these roughly correlate
    200 /// to DWARF attribute classes.
    201 ///
    202 class DIEValue {
    203   virtual void anchor();
    204 
    205 public:
    206   enum Type {
    207     isInteger,
    208     isString,
    209     isExpr,
    210     isLabel,
    211     isDelta,
    212     isEntry,
    213     isTypeSignature,
    214     isBlock,
    215     isLoc,
    216     isLocList,
    217   };
    218 
    219 protected:
    220   /// Ty - Type of data stored in the value.
    221   ///
    222   Type Ty;
    223 
    224   explicit DIEValue(Type T) : Ty(T) {}
    225   virtual ~DIEValue() {}
    226 
    227 public:
    228   // Accessors
    229   Type getType() const { return Ty; }
    230 
    231   /// EmitValue - Emit value via the Dwarf writer.
    232   ///
    233   virtual void EmitValue(AsmPrinter *AP, dwarf::Form Form) const = 0;
    234 
    235   /// SizeOf - Return the size of a value in bytes.
    236   ///
    237   virtual unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const = 0;
    238 
    239 #ifndef NDEBUG
    240   virtual void print(raw_ostream &O) const = 0;
    241   void dump() const;
    242 #endif
    243 };
    244 
    245 //===--------------------------------------------------------------------===//
    246 /// DIEInteger - An integer value DIE.
    247 ///
    248 class DIEInteger : public DIEValue {
    249   uint64_t Integer;
    250 
    251 public:
    252   explicit DIEInteger(uint64_t I) : DIEValue(isInteger), Integer(I) {}
    253 
    254   /// BestForm - Choose the best form for integer.
    255   ///
    256   static dwarf::Form BestForm(bool IsSigned, uint64_t Int) {
    257     if (IsSigned) {
    258       const int64_t SignedInt = Int;
    259       if ((char)Int == SignedInt)
    260         return dwarf::DW_FORM_data1;
    261       if ((short)Int == SignedInt)
    262         return dwarf::DW_FORM_data2;
    263       if ((int)Int == SignedInt)
    264         return dwarf::DW_FORM_data4;
    265     } else {
    266       if ((unsigned char)Int == Int)
    267         return dwarf::DW_FORM_data1;
    268       if ((unsigned short)Int == Int)
    269         return dwarf::DW_FORM_data2;
    270       if ((unsigned int)Int == Int)
    271         return dwarf::DW_FORM_data4;
    272     }
    273     return dwarf::DW_FORM_data8;
    274   }
    275 
    276   /// EmitValue - Emit integer of appropriate size.
    277   ///
    278   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    279 
    280   uint64_t getValue() const { return Integer; }
    281 
    282   /// SizeOf - Determine size of integer value in bytes.
    283   ///
    284   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    285 
    286   // Implement isa/cast/dyncast.
    287   static bool classof(const DIEValue *I) { return I->getType() == isInteger; }
    288 
    289 #ifndef NDEBUG
    290   void print(raw_ostream &O) const override;
    291 #endif
    292 };
    293 
    294 //===--------------------------------------------------------------------===//
    295 /// DIEExpr - An expression DIE.
    296 //
    297 class DIEExpr : public DIEValue {
    298   const MCExpr *Expr;
    299 
    300 public:
    301   explicit DIEExpr(const MCExpr *E) : DIEValue(isExpr), Expr(E) {}
    302 
    303   /// EmitValue - Emit expression value.
    304   ///
    305   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    306 
    307   /// getValue - Get MCExpr.
    308   ///
    309   const MCExpr *getValue() const { return Expr; }
    310 
    311   /// SizeOf - Determine size of expression value in bytes.
    312   ///
    313   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    314 
    315   // Implement isa/cast/dyncast.
    316   static bool classof(const DIEValue *E) { return E->getType() == isExpr; }
    317 
    318 #ifndef NDEBUG
    319   void print(raw_ostream &O) const override;
    320 #endif
    321 };
    322 
    323 //===--------------------------------------------------------------------===//
    324 /// DIELabel - A label DIE.
    325 //
    326 class DIELabel : public DIEValue {
    327   const MCSymbol *Label;
    328 
    329 public:
    330   explicit DIELabel(const MCSymbol *L) : DIEValue(isLabel), Label(L) {}
    331 
    332   /// EmitValue - Emit label value.
    333   ///
    334   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    335 
    336   /// getValue - Get MCSymbol.
    337   ///
    338   const MCSymbol *getValue() const { return Label; }
    339 
    340   /// SizeOf - Determine size of label value in bytes.
    341   ///
    342   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    343 
    344   // Implement isa/cast/dyncast.
    345   static bool classof(const DIEValue *L) { return L->getType() == isLabel; }
    346 
    347 #ifndef NDEBUG
    348   void print(raw_ostream &O) const override;
    349 #endif
    350 };
    351 
    352 //===--------------------------------------------------------------------===//
    353 /// DIEDelta - A simple label difference DIE.
    354 ///
    355 class DIEDelta : public DIEValue {
    356   const MCSymbol *LabelHi;
    357   const MCSymbol *LabelLo;
    358 
    359 public:
    360   DIEDelta(const MCSymbol *Hi, const MCSymbol *Lo)
    361       : DIEValue(isDelta), LabelHi(Hi), LabelLo(Lo) {}
    362 
    363   /// EmitValue - Emit delta value.
    364   ///
    365   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    366 
    367   /// SizeOf - Determine size of delta value in bytes.
    368   ///
    369   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    370 
    371   // Implement isa/cast/dyncast.
    372   static bool classof(const DIEValue *D) { return D->getType() == isDelta; }
    373 
    374 #ifndef NDEBUG
    375   void print(raw_ostream &O) const override;
    376 #endif
    377 };
    378 
    379 //===--------------------------------------------------------------------===//
    380 /// DIEString - A container for string values.
    381 ///
    382 class DIEString : public DIEValue {
    383   const DIEValue *Access;
    384   const StringRef Str;
    385 
    386 public:
    387   DIEString(const DIEValue *Acc, const StringRef S)
    388       : DIEValue(isString), Access(Acc), Str(S) {}
    389 
    390   /// getString - Grab the string out of the object.
    391   StringRef getString() const { return Str; }
    392 
    393   /// EmitValue - Emit delta value.
    394   ///
    395   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    396 
    397   /// SizeOf - Determine size of delta value in bytes.
    398   ///
    399   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    400 
    401   // Implement isa/cast/dyncast.
    402   static bool classof(const DIEValue *D) { return D->getType() == isString; }
    403 
    404 #ifndef NDEBUG
    405   void print(raw_ostream &O) const override;
    406 #endif
    407 };
    408 
    409 //===--------------------------------------------------------------------===//
    410 /// DIEEntry - A pointer to another debug information entry.  An instance of
    411 /// this class can also be used as a proxy for a debug information entry not
    412 /// yet defined (ie. types.)
    413 class DIEEntry : public DIEValue {
    414   DIE &Entry;
    415 
    416 public:
    417   explicit DIEEntry(DIE &E) : DIEValue(isEntry), Entry(E) {
    418   }
    419 
    420   DIE &getEntry() const { return Entry; }
    421 
    422   /// EmitValue - Emit debug information entry offset.
    423   ///
    424   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    425 
    426   /// SizeOf - Determine size of debug information entry in bytes.
    427   ///
    428    unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override {
    429     return Form == dwarf::DW_FORM_ref_addr ? getRefAddrSize(AP)
    430                                            : sizeof(int32_t);
    431   }
    432 
    433   /// Returns size of a ref_addr entry.
    434   static unsigned getRefAddrSize(AsmPrinter *AP);
    435 
    436   // Implement isa/cast/dyncast.
    437   static bool classof(const DIEValue *E) { return E->getType() == isEntry; }
    438 
    439 #ifndef NDEBUG
    440   void print(raw_ostream &O) const override;
    441 #endif
    442 };
    443 
    444 //===--------------------------------------------------------------------===//
    445 /// \brief A signature reference to a type unit.
    446 class DIETypeSignature : public DIEValue {
    447   const DwarfTypeUnit &Unit;
    448 
    449 public:
    450   explicit DIETypeSignature(const DwarfTypeUnit &Unit)
    451       : DIEValue(isTypeSignature), Unit(Unit) {}
    452 
    453   /// \brief Emit type unit signature.
    454   void EmitValue(AsmPrinter *Asm, dwarf::Form Form) const override;
    455 
    456   /// Returns size of a ref_sig8 entry.
    457   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override {
    458     assert(Form == dwarf::DW_FORM_ref_sig8);
    459     return 8;
    460   }
    461 
    462   // \brief Implement isa/cast/dyncast.
    463   static bool classof(const DIEValue *E) {
    464     return E->getType() == isTypeSignature;
    465   }
    466 #ifndef NDEBUG
    467   void print(raw_ostream &O) const override;
    468   void dump() const;
    469 #endif
    470 };
    471 
    472 //===--------------------------------------------------------------------===//
    473 /// DIELoc - Represents an expression location.
    474 //
    475 class DIELoc : public DIEValue, public DIE {
    476   mutable unsigned Size; // Size in bytes excluding size header.
    477 public:
    478   DIELoc() : DIEValue(isLoc), Size(0) {}
    479 
    480   /// ComputeSize - Calculate the size of the location expression.
    481   ///
    482   unsigned ComputeSize(AsmPrinter *AP) const;
    483 
    484   /// BestForm - Choose the best form for data.
    485   ///
    486   dwarf::Form BestForm(unsigned DwarfVersion) const {
    487     if (DwarfVersion > 3)
    488       return dwarf::DW_FORM_exprloc;
    489     // Pre-DWARF4 location expressions were blocks and not exprloc.
    490     if ((unsigned char)Size == Size)
    491       return dwarf::DW_FORM_block1;
    492     if ((unsigned short)Size == Size)
    493       return dwarf::DW_FORM_block2;
    494     if ((unsigned int)Size == Size)
    495       return dwarf::DW_FORM_block4;
    496     return dwarf::DW_FORM_block;
    497   }
    498 
    499   /// EmitValue - Emit location data.
    500   ///
    501   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    502 
    503   /// SizeOf - Determine size of location data in bytes.
    504   ///
    505   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    506 
    507   // Implement isa/cast/dyncast.
    508   static bool classof(const DIEValue *E) { return E->getType() == isLoc; }
    509 
    510 #ifndef NDEBUG
    511   void print(raw_ostream &O) const override;
    512 #endif
    513 };
    514 
    515 //===--------------------------------------------------------------------===//
    516 /// DIEBlock - Represents a block of values.
    517 //
    518 class DIEBlock : public DIEValue, public DIE {
    519   mutable unsigned Size; // Size in bytes excluding size header.
    520 public:
    521   DIEBlock() : DIEValue(isBlock), Size(0) {}
    522 
    523   /// ComputeSize - Calculate the size of the location expression.
    524   ///
    525   unsigned ComputeSize(AsmPrinter *AP) const;
    526 
    527   /// BestForm - Choose the best form for data.
    528   ///
    529   dwarf::Form BestForm() const {
    530     if ((unsigned char)Size == Size)
    531       return dwarf::DW_FORM_block1;
    532     if ((unsigned short)Size == Size)
    533       return dwarf::DW_FORM_block2;
    534     if ((unsigned int)Size == Size)
    535       return dwarf::DW_FORM_block4;
    536     return dwarf::DW_FORM_block;
    537   }
    538 
    539   /// EmitValue - Emit location data.
    540   ///
    541   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    542 
    543   /// SizeOf - Determine size of location data in bytes.
    544   ///
    545   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    546 
    547   // Implement isa/cast/dyncast.
    548   static bool classof(const DIEValue *E) { return E->getType() == isBlock; }
    549 
    550 #ifndef NDEBUG
    551   void print(raw_ostream &O) const override;
    552 #endif
    553 };
    554 
    555 //===--------------------------------------------------------------------===//
    556 /// DIELocList - Represents a pointer to a location list in the debug_loc
    557 /// section.
    558 //
    559 class DIELocList : public DIEValue {
    560   // Index into the .debug_loc vector.
    561   size_t Index;
    562 
    563 public:
    564   DIELocList(size_t I) : DIEValue(isLocList), Index(I) {}
    565 
    566   /// getValue - Grab the current index out.
    567   size_t getValue() const { return Index; }
    568 
    569   /// EmitValue - Emit location data.
    570   ///
    571   void EmitValue(AsmPrinter *AP, dwarf::Form Form) const override;
    572 
    573   /// SizeOf - Determine size of location data in bytes.
    574   ///
    575   unsigned SizeOf(AsmPrinter *AP, dwarf::Form Form) const override;
    576 
    577   // Implement isa/cast/dyncast.
    578   static bool classof(const DIEValue *E) { return E->getType() == isLocList; }
    579 
    580 #ifndef NDEBUG
    581   void print(raw_ostream &O) const override;
    582 #endif
    583 };
    584 
    585 } // end llvm namespace
    586 
    587 #endif
    588