DIEHash.h revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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 CODEGEN_ASMPRINTER_DIEHASH_H__
15#define CODEGEN_ASMPRINTER_DIEHASH_H__
16
17#include "DIE.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/Support/MD5.h"
20
21namespace llvm {
22
23class AsmPrinter;
24class CompileUnit;
25
26/// \brief An object containing the capability of hashing and adding hash
27/// attributes onto a DIE.
28class DIEHash {
29
30  // The entry for a particular attribute.
31  struct AttrEntry {
32    const DIEValue *Val;
33    const DIEAbbrevData *Desc;
34  };
35
36  // Collection of all attributes used in hashing a particular DIE.
37  struct DIEAttrs {
38    AttrEntry DW_AT_name;
39    AttrEntry DW_AT_accessibility;
40    AttrEntry DW_AT_address_class;
41    AttrEntry DW_AT_allocated;
42    AttrEntry DW_AT_artificial;
43    AttrEntry DW_AT_associated;
44    AttrEntry DW_AT_binary_scale;
45    AttrEntry DW_AT_bit_offset;
46    AttrEntry DW_AT_bit_size;
47    AttrEntry DW_AT_bit_stride;
48    AttrEntry DW_AT_byte_size;
49    AttrEntry DW_AT_byte_stride;
50    AttrEntry DW_AT_const_expr;
51    AttrEntry DW_AT_const_value;
52    AttrEntry DW_AT_containing_type;
53    AttrEntry DW_AT_count;
54    AttrEntry DW_AT_data_bit_offset;
55    AttrEntry DW_AT_data_location;
56    AttrEntry DW_AT_data_member_location;
57    AttrEntry DW_AT_decimal_scale;
58    AttrEntry DW_AT_decimal_sign;
59    AttrEntry DW_AT_default_value;
60    AttrEntry DW_AT_digit_count;
61    AttrEntry DW_AT_discr;
62    AttrEntry DW_AT_discr_list;
63    AttrEntry DW_AT_discr_value;
64    AttrEntry DW_AT_encoding;
65    AttrEntry DW_AT_enum_class;
66    AttrEntry DW_AT_endianity;
67    AttrEntry DW_AT_explicit;
68    AttrEntry DW_AT_is_optional;
69    AttrEntry DW_AT_location;
70    AttrEntry DW_AT_lower_bound;
71    AttrEntry DW_AT_mutable;
72    AttrEntry DW_AT_ordering;
73    AttrEntry DW_AT_picture_string;
74    AttrEntry DW_AT_prototyped;
75    AttrEntry DW_AT_small;
76    AttrEntry DW_AT_segment;
77    AttrEntry DW_AT_string_length;
78    AttrEntry DW_AT_threads_scaled;
79    AttrEntry DW_AT_upper_bound;
80    AttrEntry DW_AT_use_location;
81    AttrEntry DW_AT_use_UTF8;
82    AttrEntry DW_AT_variable_parameter;
83    AttrEntry DW_AT_virtuality;
84    AttrEntry DW_AT_visibility;
85    AttrEntry DW_AT_vtable_elem_location;
86    AttrEntry DW_AT_type;
87
88    // Insert any additional ones here...
89  };
90
91public:
92  DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
93
94  /// \brief Computes the ODR signature.
95  uint64_t computeDIEODRSignature(const DIE &Die);
96
97  /// \brief Computes the CU signature.
98  uint64_t computeCUSignature(const DIE &Die);
99
100  /// \brief Computes the type signature.
101  uint64_t computeTypeSignature(const DIE &Die);
102
103  // Helper routines to process parts of a DIE.
104private:
105  /// \brief Adds the parent context of \param Die to the hash.
106  void addParentContext(const DIE &Die);
107
108  /// \brief Adds the attributes of \param Die to the hash.
109  void addAttributes(const DIE &Die);
110
111  /// \brief Computes the full DWARF4 7.27 hash of the DIE.
112  void computeHash(const DIE &Die);
113
114  // Routines that add DIEValues to the hash.
115public:
116  /// \brief Adds \param Value to the hash.
117  void update(uint8_t Value) { Hash.update(Value); }
118
119  /// \brief Encodes and adds \param Value to the hash as a ULEB128.
120  void addULEB128(uint64_t Value);
121
122  /// \brief Encodes and adds \param Value to the hash as a SLEB128.
123  void addSLEB128(int64_t Value);
124
125private:
126  /// \brief Adds \param Str to the hash and includes a NULL byte.
127  void addString(StringRef Str);
128
129  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
130  /// structure.
131  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
132
133  /// \brief Hashes the attributes in \param Attrs in order.
134  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
135
136  /// \brief Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
137  /// DW_FORM_exprloc.
138  void hashBlockData(const SmallVectorImpl<DIEValue *> &Values);
139
140  /// \brief Hashes the contents pointed to in the .debug_loc section.
141  void hashLocList(const DIELocList &LocList);
142
143  /// \brief Hashes an individual attribute.
144  void hashAttribute(AttrEntry Attr, dwarf::Tag Tag);
145
146  /// \brief Hashes an attribute that refers to another DIE.
147  void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
148                    const DIE &Entry);
149
150  /// \brief Hashes a reference to a named type in such a way that is
151  /// independent of whether that type is described by a declaration or a
152  /// definition.
153  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
154                                StringRef Name);
155
156  /// \brief Hashes a reference to a previously referenced type DIE.
157  void hashRepeatedTypeReference(dwarf::Attribute Attribute,
158                                 unsigned DieNumber);
159
160  void hashNestedType(const DIE &Die, StringRef Name);
161
162private:
163  MD5 Hash;
164  AsmPrinter *AP;
165  DenseMap<const DIE *, unsigned> Numbering;
166};
167}
168
169#endif
170