DIEHash.h revision 15ab9f4aaa0bebe50c1367963c409d929bede030 
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#include "llvm/Support/MD5.h"
15
16namespace llvm {
17
18class CompileUnit;
19
20/// \brief An object containing the capability of hashing and adding hash
21/// attributes onto a DIE.
22class DIEHash {
23  // The entry for a particular attribute.
24  struct AttrEntry {
25    const DIEValue *Val;
26    const DIEAbbrevData *Desc;
27  };
28
29  // Collection of all attributes used in hashing a particular DIE.
30  struct DIEAttrs {
31    AttrEntry DW_AT_name;
32  };
33
34public:
35  /// \brief Computes the ODR signature
36  uint64_t computeDIEODRSignature(DIE *Die);
37
38  /// \brief Computes the CU signature
39  uint64_t computeCUSignature(DIE *Die);
40
41  // Helper routines to process parts of a DIE.
42private:
43  /// \brief Adds the parent context of \param Die to the hash.
44  void addParentContext(DIE *Die);
45
46  /// \brief Adds the attributes of \param Die to the hash.
47  void addAttributes(DIE *Die);
48
49  /// \brief Computes the full DWARF4 7.27 hash of the DIE.
50  void computeHash(DIE *Die);
51
52  // Routines that add DIEValues to the hash.
53private:
54  /// \brief Encodes and adds \param Value to the hash as a ULEB128.
55  void addULEB128(uint64_t Value);
56
57  /// \brief Adds \param Str to the hash and includes a NULL byte.
58  void addString(StringRef Str);
59
60  /// \brief Collects the attributes of DIE \param Die into the \param Attrs
61  /// structure.
62  void collectAttributes(DIE *Die, DIEAttrs *Attrs);
63
64  /// \brief Hashes the attributes in \param Attrs in order.
65  void hashAttributes(DIEAttrs Attrs);
66
67  /// \brief Hashes an individual attribute.
68  void hashAttribute(AttrEntry Attr);
69
70private:
71  MD5 Hash;
72};
73}
74