DIEHash.h revision f1545a219744c1ae66137e64d1c456cd8e924eb7 
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 "llvm/ADT/DenseMap.h"
15#include "llvm/Support/MD5.h"
16
17namespace llvm {
18
19class CompileUnit;
20
21/// \brief An object containing the capability of hashing and adding hash
22/// attributes onto a DIE.
23class DIEHash {
24  // The entry for a particular attribute.
25  struct AttrEntry {
26    const DIEValue *Val;
27    const DIEAbbrevData *Desc;
28  };
29
30  // Collection of all attributes used in hashing a particular DIE.
31  struct DIEAttrs {
32    AttrEntry DW_AT_name;
33    AttrEntry DW_AT_accessibility;
34    AttrEntry DW_AT_address_class;
35    AttrEntry DW_AT_allocated;
36    AttrEntry DW_AT_artificial;
37    AttrEntry DW_AT_associated;
38    AttrEntry DW_AT_binary_scale;
39    AttrEntry DW_AT_bit_offset;
40    AttrEntry DW_AT_bit_size;
41    AttrEntry DW_AT_bit_stride;
42    AttrEntry DW_AT_byte_size;
43    AttrEntry DW_AT_byte_stride;
44    AttrEntry DW_AT_const_expr;
45    AttrEntry DW_AT_const_value;
46    AttrEntry DW_AT_containing_type;
47    AttrEntry DW_AT_count;
48    AttrEntry DW_AT_data_bit_offset;
49    AttrEntry DW_AT_data_location;
50    AttrEntry DW_AT_data_member_location;
51    AttrEntry DW_AT_decimal_scale;
52    AttrEntry DW_AT_decimal_sign;
53    AttrEntry DW_AT_default_value;
54    AttrEntry DW_AT_digit_count;
55    AttrEntry DW_AT_discr;
56    AttrEntry DW_AT_discr_list;
57    AttrEntry DW_AT_discr_value;
58    AttrEntry DW_AT_encoding;
59    AttrEntry DW_AT_enum_class;
60    AttrEntry DW_AT_endianity;
61    AttrEntry DW_AT_explicit;
62    AttrEntry DW_AT_is_optional;
63    AttrEntry DW_AT_location;
64    AttrEntry DW_AT_lower_bound;
65    AttrEntry DW_AT_mutable;
66    AttrEntry DW_AT_ordering;
67    AttrEntry DW_AT_picture_string;
68    AttrEntry DW_AT_prototyped;
69    AttrEntry DW_AT_small;
70    AttrEntry DW_AT_segment;
71    AttrEntry DW_AT_string_length;
72    AttrEntry DW_AT_threads_scaled;
73    AttrEntry DW_AT_upper_bound;
74    AttrEntry DW_AT_use_location;
75    AttrEntry DW_AT_use_UTF8;
76    AttrEntry DW_AT_variable_parameter;
77    AttrEntry DW_AT_virtuality;
78    AttrEntry DW_AT_visibility;
79    AttrEntry DW_AT_vtable_elem_location;
80    AttrEntry DW_AT_type;
81
82    // Insert any additional ones here...
83  };
84
85public:
86  /// \brief Computes the ODR signature.
87  uint64_t computeDIEODRSignature(DIE *Die);
88
89  /// \brief Computes the CU signature.
90  uint64_t computeCUSignature(DIE *Die);
91
92  /// \brief Computes the type signature.
93  uint64_t computeTypeSignature(DIE *Die);
94
95  // Helper routines to process parts of a DIE.
96private:
97  /// \brief Adds the parent context of \param Die to the hash.
98  void addParentContext(DIE *Die);
99
100  /// \brief Adds the attributes of \param Die to the hash.
101  void addAttributes(DIE *Die);
102
103  /// \brief Computes the full DWARF4 7.27 hash of the DIE.
104  void computeHash(DIE *Die);
105
106  // Routines that add DIEValues to the hash.
107private:
108  /// \brief Encodes and adds \param Value to the hash as a ULEB128.
109  void addULEB128(uint64_t Value);
110
111  /// \brief Encodes and adds \param Value to the hash as a SLEB128.
112  void addSLEB128(int64_t Value);
113
114  /// \brief Adds \param Str to the hash and includes a NULL byte.
115  void addString(StringRef Str);
116
117  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
118  /// structure.
119  void collectAttributes(DIE *Die, DIEAttrs &Attrs);
120
121  /// \brief Hashes the attributes in \param Attrs in order.
122  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
123
124  /// \brief Hashes an individual attribute.
125  void hashAttribute(AttrEntry Attr, dwarf::Tag Tag);
126
127private:
128  MD5 Hash;
129  DenseMap<DIE*, unsigned> Numbering;
130};
131}
132