LLVM  12.0.0git
DIEHash.h
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1 //===-- llvm/CodeGen/DIEHash.h - Dwarf Hashing Framework -------*- C++ -*--===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains support for DWARF4 hashing of DIEs.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
14 #define LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
15 
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/CodeGen/DIE.h"
18 #include "llvm/Support/MD5.h"
19 
20 namespace llvm {
21 
22 class AsmPrinter;
23 
24 /// An object containing the capability of hashing and adding hash
25 /// attributes onto a DIE.
26 class DIEHash {
27  // Collection of all attributes used in hashing a particular DIE.
28  struct DIEAttrs {
29 #define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME;
30 #include "DIEHashAttributes.def"
31  };
32 
33 public:
34  DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
35 
36  /// Computes the CU signature.
37  uint64_t computeCUSignature(StringRef DWOName, const DIE &Die);
38 
39  /// Computes the type signature.
40  uint64_t computeTypeSignature(const DIE &Die);
41 
42  // Helper routines to process parts of a DIE.
43 private:
44  /// Adds the parent context of \param Parent to the hash.
45  void addParentContext(const DIE &Parent);
46 
47  /// Adds the attributes of \param Die to the hash.
48  void addAttributes(const DIE &Die);
49 
50  /// Computes the full DWARF4 7.27 hash of the DIE.
51  void computeHash(const DIE &Die);
52 
53  // Routines that add DIEValues to the hash.
54 public:
55  /// Adds \param Value to the hash.
56  void update(uint8_t Value) { Hash.update(Value); }
57 
58  /// Encodes and adds \param Value to the hash as a ULEB128.
59  void addULEB128(uint64_t Value);
60 
61  /// Encodes and adds \param Value to the hash as a SLEB128.
62  void addSLEB128(int64_t Value);
63 
64 private:
65  /// Adds \param Str to the hash and includes a NULL byte.
66  void addString(StringRef Str);
67 
68  /// Collects the attributes of DIE \param Die into the \param Attrs
69  /// structure.
70  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
71 
72  /// Hashes the attributes in \param Attrs in order.
73  void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
74 
75  /// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
76  /// DW_FORM_exprloc.
77  void hashBlockData(const DIE::const_value_range &Values);
78 
79  /// Hashes the contents pointed to in the .debug_loc section.
80  void hashLocList(const DIELocList &LocList);
81 
82  /// Hashes an individual attribute.
83  void hashAttribute(const DIEValue &Value, dwarf::Tag Tag);
84 
85  /// Hashes an attribute that refers to another DIE.
86  void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
87  const DIE &Entry);
88 
89  /// Hashes a reference to a named type in such a way that is
90  /// independent of whether that type is described by a declaration or a
91  /// definition.
92  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
93  StringRef Name);
94 
95  /// Hashes a reference to a previously referenced type DIE.
96  void hashRepeatedTypeReference(dwarf::Attribute Attribute,
97  unsigned DieNumber);
98 
99  void hashNestedType(const DIE &Die, StringRef Name);
100 
101 private:
102  MD5 Hash;
103  AsmPrinter *AP;
105 };
106 }
107 
108 #endif
Global Value Numbering
Definition: NewGVN.cpp:4224
An object containing the capability of hashing and adding hash attributes onto a DIE.
Definition: DIEHash.h:26
DIEHash(AsmPrinter *A=nullptr)
Definition: DIEHash.h:34
This class represents lattice values for constants.
Definition: AllocatorList.h:23
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
Attribute
Attributes.
Definition: Dwarf.h:103
void addULEB128(uint64_t Value)
Encodes and adds.
Definition: DIEHash.cpp:52
Represents a pointer to a location list in the debug_loc section.
Definition: DIE.h:331
uint64_t computeCUSignature(StringRef DWOName, const DIE &Die)
Computes the CU signature.
Definition: DIEHash.cpp:382
uint64_t computeTypeSignature(const DIE &Die)
Computes the type signature.
Definition: DIEHash.cpp:405
constexpr char Attrs[]
Key for Kernel::Metadata::mAttrs.
A structured debug information entry.
Definition: DIE.h:723
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:81
A range adaptor for a pair of iterators.
void update(uint8_t Value)
Adds.
Definition: DIEHash.h:56
void addSLEB128(int64_t Value)
Encodes and adds.
Definition: DIEHash.cpp:63
Definition: MD5.h:41
LLVM Value Representation.
Definition: Value.h:74
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57