DIEHash.h revision a9a8f0f432966438800ffabb1b740a4cc8cd2599 
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#include "DIE.h"
15#include "llvm/ADT/DenseMap.h"
16#include "llvm/Support/MD5.h"
17
18namespace llvm {
19
20class CompileUnit;
21
22/// \brief An object containing the capability of hashing and adding hash
23/// attributes onto a DIE.
24class DIEHash {
25  // The entry for a particular attribute.
26  struct AttrEntry {
27    const DIEValue *Val;
28    const DIEAbbrevData *Desc;
29  };
30
31  // Collection of all attributes used in hashing a particular DIE.
32  struct DIEAttrs {
33    AttrEntry DW_AT_name;
34    AttrEntry DW_AT_accessibility;
35    AttrEntry DW_AT_address_class;
36    AttrEntry DW_AT_allocated;
37    AttrEntry DW_AT_artificial;
38    AttrEntry DW_AT_associated;
39    AttrEntry DW_AT_binary_scale;
40    AttrEntry DW_AT_bit_offset;
41    AttrEntry DW_AT_bit_size;
42    AttrEntry DW_AT_bit_stride;
43    AttrEntry DW_AT_byte_size;
44    AttrEntry DW_AT_byte_stride;
45    AttrEntry DW_AT_const_expr;
46    AttrEntry DW_AT_const_value;
47    AttrEntry DW_AT_containing_type;
48    AttrEntry DW_AT_count;
49    AttrEntry DW_AT_data_bit_offset;
50    AttrEntry DW_AT_data_location;
51    AttrEntry DW_AT_data_member_location;
52    AttrEntry DW_AT_decimal_scale;
53    AttrEntry DW_AT_decimal_sign;
54    AttrEntry DW_AT_default_value;
55    AttrEntry DW_AT_digit_count;
56    AttrEntry DW_AT_discr;
57    AttrEntry DW_AT_discr_list;
58    AttrEntry DW_AT_discr_value;
59    AttrEntry DW_AT_encoding;
60    AttrEntry DW_AT_enum_class;
61    AttrEntry DW_AT_endianity;
62    AttrEntry DW_AT_explicit;
63    AttrEntry DW_AT_is_optional;
64    AttrEntry DW_AT_location;
65    AttrEntry DW_AT_lower_bound;
66    AttrEntry DW_AT_mutable;
67    AttrEntry DW_AT_ordering;
68    AttrEntry DW_AT_picture_string;
69    AttrEntry DW_AT_prototyped;
70    AttrEntry DW_AT_small;
71    AttrEntry DW_AT_segment;
72    AttrEntry DW_AT_string_length;
73    AttrEntry DW_AT_threads_scaled;
74    AttrEntry DW_AT_upper_bound;
75    AttrEntry DW_AT_use_location;
76    AttrEntry DW_AT_use_UTF8;
77    AttrEntry DW_AT_variable_parameter;
78    AttrEntry DW_AT_virtuality;
79    AttrEntry DW_AT_visibility;
80    AttrEntry DW_AT_vtable_elem_location;
81    AttrEntry DW_AT_type;
82
83    // Insert any additional ones here...
84  };
85
86public:
87  /// \brief Computes the ODR signature.
88  uint64_t computeDIEODRSignature(const DIE &Die);
89
90  /// \brief Computes the CU signature.
91  uint64_t computeCUSignature(const DIE &Die);
92
93  /// \brief Computes the type signature.
94  uint64_t computeTypeSignature(const DIE &Die);
95
96  // Helper routines to process parts of a DIE.
97private:
98  /// \brief Adds the parent context of \param Die to the hash.
99  void addParentContext(const DIE &Die);
100
101  /// \brief Adds the attributes of \param Die to the hash.
102  void addAttributes(const DIE &Die);
103
104  /// \brief Computes the full DWARF4 7.27 hash of the DIE.
105  void computeHash(const DIE &Die);
106
107  // Routines that add DIEValues to the hash.
108private:
109  /// \brief Encodes and adds \param Value to the hash as a ULEB128.
110  void addULEB128(uint64_t Value);
111
112  /// \brief Encodes and adds \param Value to the hash as a SLEB128.
113  void addSLEB128(int64_t Value);
114
115  /// \brief Adds \param Str to the hash and includes a NULL byte.
116  void addString(StringRef Str);
117
118  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
119  /// structure.
120  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
121
122  /// \brief Hashes the attributes in \param Attrs in order.
123  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
124
125  /// \brief Hashes an individual attribute.
126  void hashAttribute(AttrEntry Attr, dwarf::Tag Tag);
127
128  /// \brief Hashes an attribute that refers to another DIE.
129  void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
130                    const DIE &Entry);
131
132  /// \brief Hashes a reference to a named type in such a way that is
133  /// independent of whether that type is described by a declaration or a
134  /// definition.
135  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
136                                StringRef Name);
137
138  /// \brief Hashes a reference to a previously referenced type DIE.
139  void hashRepeatedTypeReference(dwarf::Attribute Attribute, unsigned DieNumber);
140
141  void hashNestedType(const DIE &Die, StringRef Name);
142
143private:
144  MD5 Hash;
145  DenseMap<const DIE *, unsigned> Numbering;
146};
147}
148