LLVM  4.0.0
DIEHash.h
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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 
21 namespace llvm {
22 
23 class AsmPrinter;
24 class CompileUnit;
25 
26 /// \brief An object containing the capability of hashing and adding hash
27 /// attributes onto a DIE.
28 class 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 
84 public:
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.
94 private:
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.
105 public:
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 
115 private:
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(const 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 
152 private:
153  MD5 Hash;
154  AsmPrinter *AP;
156 };
157 }
158 
159 #endif
An object containing the capability of hashing and adding hash attributes onto a DIE.
Definition: DIEHash.h:28
uint64_t computeCUSignature(const DIE &Die)
Computes the CU signature.
Definition: DIEHash.cpp:481
DIEHash(AsmPrinter *A=nullptr)
Definition: DIEHash.h:85
Attribute
Attributes.
Definition: Dwarf.h:94
void addULEB128(uint64_t Value)
Encodes and adds.
Definition: DIEHash.cpp:55
Represents a pointer to a location list in the debug_loc section.
Definition: DIE.h:312
uint64_t computeTypeSignature(const DIE &Die)
Computes the type signature.
Definition: DIEHash.cpp:502
void update(ArrayRef< uint8_t > Data)
Updates the hash for the byte stream provided.
Definition: MD5.cpp:187
A structured debug information entry.
Definition: DIE.h:655
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:67
A range adaptor for a pair of iterators.
void update(uint8_t Value)
Adds.
Definition: DIEHash.h:107
void addSLEB128(int64_t Value)
Encodes and adds.
Definition: DIEHash.cpp:66
Definition: MD5.h:39
LLVM Value Representation.
Definition: Value.h:71
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:47
static GCRegistry::Add< ErlangGC > A("erlang","erlang-compatible garbage collector")