DIEHash.h revision 288943 
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 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.
108public:
109  /// \brief Adds \param Value to the hash.
110  void update(uint8_t Value) { Hash.update(Value); }
111
112  /// \brief Encodes and adds \param Value to the hash as a ULEB128.
113  void addULEB128(uint64_t Value);
114
115  /// \brief Encodes and adds \param Value to the hash as a SLEB128.
116  void addSLEB128(int64_t Value);
117
118private:
119  /// \brief Adds \param Str to the hash and includes a NULL byte.
120  void addString(StringRef Str);
121
122  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
123  /// structure.
124  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
125
126  /// \brief Hashes the attributes in \param Attrs in order.
127  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
128
129  /// \brief Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
130  /// DW_FORM_exprloc.
131  void hashBlockData(const DIE::const_value_range &Values);
132
133  /// \brief Hashes the contents pointed to in the .debug_loc section.
134  void hashLocList(const DIELocList &LocList);
135
136  /// \brief Hashes an individual attribute.
137  void hashAttribute(DIEValue Value, dwarf::Tag Tag);
138
139  /// \brief Hashes an attribute that refers to another DIE.
140  void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
141                    const DIE &Entry);
142
143  /// \brief Hashes a reference to a named type in such a way that is
144  /// independent of whether that type is described by a declaration or a
145  /// definition.
146  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
147                                StringRef Name);
148
149  /// \brief Hashes a reference to a previously referenced type DIE.
150  void hashRepeatedTypeReference(dwarf::Attribute Attribute,
151                                 unsigned DieNumber);
152
153  void hashNestedType(const DIE &Die, StringRef Name);
154
155private:
156  MD5 Hash;
157  AsmPrinter *AP;
158  DenseMap<const DIE *, unsigned> Numbering;
159};
160}
161
162#endif
163