DIEHash.h revision cddc3e03e4ec99c0268c03a126195173e519ed58 
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
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  // Collection of all attributes used in hashing a particular DIE.
30  struct DIEAttrs {
31    DIEValue DW_AT_name;
32    DIEValue DW_AT_accessibility;
33    DIEValue DW_AT_address_class;
34    DIEValue DW_AT_allocated;
35    DIEValue DW_AT_artificial;
36    DIEValue DW_AT_associated;
37    DIEValue DW_AT_binary_scale;
38    DIEValue DW_AT_bit_offset;
39    DIEValue DW_AT_bit_size;
40    DIEValue DW_AT_bit_stride;
41    DIEValue DW_AT_byte_size;
42    DIEValue DW_AT_byte_stride;
43    DIEValue DW_AT_const_expr;
44    DIEValue DW_AT_const_value;
45    DIEValue DW_AT_containing_type;
46    DIEValue DW_AT_count;
47    DIEValue DW_AT_data_bit_offset;
48    DIEValue DW_AT_data_location;
49    DIEValue DW_AT_data_member_location;
50    DIEValue DW_AT_decimal_scale;
51    DIEValue DW_AT_decimal_sign;
52    DIEValue DW_AT_default_value;
53    DIEValue DW_AT_digit_count;
54    DIEValue DW_AT_discr;
55    DIEValue DW_AT_discr_list;
56    DIEValue DW_AT_discr_value;
57    DIEValue DW_AT_encoding;
58    DIEValue DW_AT_enum_class;
59    DIEValue DW_AT_endianity;
60    DIEValue DW_AT_explicit;
61    DIEValue DW_AT_is_optional;
62    DIEValue DW_AT_location;
63    DIEValue DW_AT_lower_bound;
64    DIEValue DW_AT_mutable;
65    DIEValue DW_AT_ordering;
66    DIEValue DW_AT_picture_string;
67    DIEValue DW_AT_prototyped;
68    DIEValue DW_AT_small;
69    DIEValue DW_AT_segment;
70    DIEValue DW_AT_string_length;
71    DIEValue DW_AT_threads_scaled;
72    DIEValue DW_AT_upper_bound;
73    DIEValue DW_AT_use_location;
74    DIEValue DW_AT_use_UTF8;
75    DIEValue DW_AT_variable_parameter;
76    DIEValue DW_AT_virtuality;
77    DIEValue DW_AT_visibility;
78    DIEValue DW_AT_vtable_elem_location;
79    DIEValue DW_AT_type;
80
81    // Insert any additional ones here...
82  };
83
84public:
85  DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
86
87  /// \brief Computes the CU signature.
88  uint64_t computeCUSignature(const DIE &Die);
89
90  /// \brief Computes the type signature.
91  uint64_t computeTypeSignature(const DIE &Die);
92
93  // Helper routines to process parts of a DIE.
94private:
95  /// \brief Adds the parent context of \param Die to the hash.
96  void addParentContext(const DIE &Die);
97
98  /// \brief Adds the attributes of \param Die to the hash.
99  void addAttributes(const DIE &Die);
100
101  /// \brief Computes the full DWARF4 7.27 hash of the DIE.
102  void computeHash(const DIE &Die);
103
104  // Routines that add DIEValues to the hash.
105public:
106  /// \brief Adds \param Value to the hash.
107  void update(uint8_t Value) { Hash.update(Value); }
108
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
115private:
116  /// \brief Adds \param Str to the hash and includes a NULL byte.
117  void addString(StringRef Str);
118
119  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
120  /// structure.
121  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
122
123  /// \brief Hashes the attributes in \param Attrs in order.
124  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
125
126  /// \brief Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
127  /// DW_FORM_exprloc.
128  void hashBlockData(const DIE::const_value_range &Values);
129
130  /// \brief Hashes the contents pointed to in the .debug_loc section.
131  void hashLocList(const DIELocList &LocList);
132
133  /// \brief Hashes an individual attribute.
134  void hashAttribute(DIEValue Value, dwarf::Tag Tag);
135
136  /// \brief Hashes an attribute that refers to another DIE.
137  void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
138                    const DIE &Entry);
139
140  /// \brief Hashes a reference to a named type in such a way that is
141  /// independent of whether that type is described by a declaration or a
142  /// definition.
143  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
144                                StringRef Name);
145
146  /// \brief Hashes a reference to a previously referenced type DIE.
147  void hashRepeatedTypeReference(dwarf::Attribute Attribute,
148                                 unsigned DieNumber);
149
150  void hashNestedType(const DIE &Die, StringRef Name);
151
152private:
153  MD5 Hash;
154  AsmPrinter *AP;
155  DenseMap<const DIE *, unsigned> Numbering;
156};
157}
158
159#endif
160