lib/CodeGen/AsmPrinter/DIEHash.h

   1 //===-- llvm/CodeGen/DIEHash.h - Dwarf Hashing Framework -------*- 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 // This file contains support for DWARF4 hashing of DIEs.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
  15 #define LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
  16
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/CodeGen/DIE.h"
  19 #include "llvm/Support/MD5.h"
  20
  21 namespace llvm {
  22
  23 class AsmPrinter;
  24 class CompileUnit;
  25
  26 /// \brief An object containing the capability of hashing and adding hash
  27 /// attributes onto a DIE.
  28 class DIEHash {
  29   // Collection of all attributes used in hashing a particular DIE.
  30   struct DIEAttrs {
  31 #define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME;
  32 #include "DIEHashAttributes.def"
  33   };
  34
  35 public:
  36   DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
  37
  38   /// \brief Computes the CU signature.
  39   uint64_t computeCUSignature(StringRef DWOName, const DIE &Die);
  40
  41   /// \brief Computes the type signature.
  42   uint64_t computeTypeSignature(const DIE &Die);
  43
  44   // Helper routines to process parts of a DIE.
  45 private:
  46   /// \brief Adds the parent context of \param Die to the hash.
  47   void addParentContext(const DIE &Die);
  48
  49   /// \brief Adds the attributes of \param Die to the hash.
  50   void addAttributes(const DIE &Die);
  51
  52   /// \brief Computes the full DWARF4 7.27 hash of the DIE.
  53   void computeHash(const DIE &Die);
  54
  55   // Routines that add DIEValues to the hash.
  56 public:
  57   /// \brief Adds \param Value to the hash.
  58   void update(uint8_t Value) { Hash.update(Value); }
  59
  60   /// \brief Encodes and adds \param Value to the hash as a ULEB128.
  61   void addULEB128(uint64_t Value);
  62
  63   /// \brief Encodes and adds \param Value to the hash as a SLEB128.
  64   void addSLEB128(int64_t Value);
  65
  66 private:
  67   /// \brief Adds \param Str to the hash and includes a NULL byte.
  68   void addString(StringRef Str);
  69
  70   /// \brief Collects the attributes of DIE \param Die into the \param Attrs
  71   /// structure.
  72   void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
  73
  74   /// \brief Hashes the attributes in \param Attrs in order.
  75   void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
  76
  77   /// \brief Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
  78   /// DW_FORM_exprloc.
  79   void hashBlockData(const DIE::const_value_range &Values);
  80
  81   /// \brief Hashes the contents pointed to in the .debug_loc section.
  82   void hashLocList(const DIELocList &LocList);
  83
  84   /// \brief Hashes an individual attribute.
  85   void hashAttribute(const DIEValue &Value, dwarf::Tag Tag);
  86
  87   /// \brief Hashes an attribute that refers to another DIE.
  88   void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
  89                     const DIE &Entry);
  90
  91   /// \brief Hashes a reference to a named type in such a way that is
  92   /// independent of whether that type is described by a declaration or a
  93   /// definition.
  94   void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
  95                                 StringRef Name);
  96
  97   /// \brief Hashes a reference to a previously referenced type DIE.
  98   void hashRepeatedTypeReference(dwarf::Attribute Attribute,
  99                                  unsigned DieNumber);
 100
 101   void hashNestedType(const DIE &Die, StringRef Name);
 102
 103 private:
 104   MD5 Hash;
 105   AsmPrinter *AP;
 106   DenseMap<const DIE *, unsigned> Numbering;
 107 };
 108 }
 109
 110 #endif