1//===- BitCodes.h - Enum values for the bitcode format ----------*- 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 header Bitcode enum values.
11//
12// The enum values defined in this file should be considered permanent.  If
13// new features are added, they should have values added at the end of the
14// respective lists.
15//
16//===----------------------------------------------------------------------===//
17
18#ifndef LLVM_BITCODE_BITCODES_H
19#define LLVM_BITCODE_BITCODES_H
20
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/Support/DataTypes.h"
23#include "llvm/Support/ErrorHandling.h"
24#include <cassert>
25
26namespace llvm {
27/// Offsets of the 32-bit fields of bitcode wrapper header.
28static const unsigned BWH_MagicField = 0 * 4;
29static const unsigned BWH_VersionField = 1 * 4;
30static const unsigned BWH_OffsetField = 2 * 4;
31static const unsigned BWH_SizeField = 3 * 4;
32static const unsigned BWH_CPUTypeField = 4 * 4;
33static const unsigned BWH_HeaderSize = 5 * 4;
34
35namespace bitc {
36  enum StandardWidths {
37    BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
38    CodeLenWidth   = 4,  // Codelen are VBR-4.
39    BlockSizeWidth = 32  // BlockSize up to 2^32 32-bit words = 16GB per block.
40  };
41
42  // The standard abbrev namespace always has a way to exit a block, enter a
43  // nested block, define abbrevs, and define an unabbreviated record.
44  enum FixedAbbrevIDs {
45    END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
46    ENTER_SUBBLOCK = 1,
47
48    /// DEFINE_ABBREV - Defines an abbrev for the current block.  It consists
49    /// of a vbr5 for # operand infos.  Each operand info is emitted with a
50    /// single bit to indicate if it is a literal encoding.  If so, the value is
51    /// emitted with a vbr8.  If not, the encoding is emitted as 3 bits followed
52    /// by the info value as a vbr5 if needed.
53    DEFINE_ABBREV = 2,
54
55    // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
56    // a vbr6 for the # operands, followed by vbr6's for each operand.
57    UNABBREV_RECORD = 3,
58
59    // This is not a code, this is a marker for the first abbrev assignment.
60    FIRST_APPLICATION_ABBREV = 4
61  };
62
63  /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
64  /// block, which contains metadata about other blocks in the file.
65  enum StandardBlockIDs {
66    /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
67    /// standard abbrevs that should be available to all blocks of a specified
68    /// ID.
69    BLOCKINFO_BLOCK_ID = 0,
70
71    // Block IDs 1-7 are reserved for future expansion.
72    FIRST_APPLICATION_BLOCKID = 8
73  };
74
75  /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
76  /// blocks.
77  enum BlockInfoCodes {
78    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
79    // block, instead of the BlockInfo block.
80
81    BLOCKINFO_CODE_SETBID        = 1, // SETBID: [blockid#]
82    BLOCKINFO_CODE_BLOCKNAME     = 2, // BLOCKNAME: [name]
83    BLOCKINFO_CODE_SETRECORDNAME = 3  // BLOCKINFO_CODE_SETRECORDNAME:
84                                      //                             [id, name]
85  };
86
87} // End bitc namespace
88
89/// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
90/// This is actually a union of two different things:
91///   1. It could be a literal integer value ("the operand is always 17").
92///   2. It could be an encoding specification ("this operand encoded like so").
93///
94class BitCodeAbbrevOp {
95  uint64_t Val;           // A literal value or data for an encoding.
96  bool IsLiteral : 1;     // Indicate whether this is a literal value or not.
97  unsigned Enc   : 3;     // The encoding to use.
98public:
99  enum Encoding {
100    Fixed = 1,  // A fixed width field, Val specifies number of bits.
101    VBR   = 2,  // A VBR field where Val specifies the width of each chunk.
102    Array = 3,  // A sequence of fields, next field species elt encoding.
103    Char6 = 4,  // A 6-bit fixed field which maps to [a-zA-Z0-9._].
104    Blob  = 5   // 32-bit aligned array of 8-bit characters.
105  };
106
107  explicit BitCodeAbbrevOp(uint64_t V) :  Val(V), IsLiteral(true) {}
108  explicit BitCodeAbbrevOp(Encoding E, uint64_t Data = 0)
109    : Val(Data), IsLiteral(false), Enc(E) {}
110
111  bool isLiteral() const  { return IsLiteral; }
112  bool isEncoding() const { return !IsLiteral; }
113
114  // Accessors for literals.
115  uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }
116
117  // Accessors for encoding info.
118  Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
119  uint64_t getEncodingData() const {
120    assert(isEncoding() && hasEncodingData());
121    return Val;
122  }
123
124  bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
125  static bool hasEncodingData(Encoding E) {
126    switch (E) {
127    case Fixed:
128    case VBR:
129      return true;
130    case Array:
131    case Char6:
132    case Blob:
133      return false;
134    }
135    report_fatal_error("Invalid encoding");
136  }
137
138  /// isChar6 - Return true if this character is legal in the Char6 encoding.
139  static bool isChar6(char C) {
140    if (C >= 'a' && C <= 'z') return true;
141    if (C >= 'A' && C <= 'Z') return true;
142    if (C >= '0' && C <= '9') return true;
143    if (C == '.' || C == '_') return true;
144    return false;
145  }
146  static unsigned EncodeChar6(char C) {
147    if (C >= 'a' && C <= 'z') return C-'a';
148    if (C >= 'A' && C <= 'Z') return C-'A'+26;
149    if (C >= '0' && C <= '9') return C-'0'+26+26;
150    if (C == '.')             return 62;
151    if (C == '_')             return 63;
152    llvm_unreachable("Not a value Char6 character!");
153  }
154
155  static char DecodeChar6(unsigned V) {
156    assert((V & ~63) == 0 && "Not a Char6 encoded character!");
157    return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._"
158        [V];
159  }
160
161};
162
163template <> struct isPodLike<BitCodeAbbrevOp> { static const bool value=true; };
164
165/// BitCodeAbbrev - This class represents an abbreviation record.  An
166/// abbreviation allows a complex record that has redundancy to be stored in a
167/// specialized format instead of the fully-general, fully-vbr, format.
168class BitCodeAbbrev {
169  SmallVector<BitCodeAbbrevOp, 32> OperandList;
170
171public:
172  unsigned getNumOperandInfos() const {
173    return static_cast<unsigned>(OperandList.size());
174  }
175  const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
176    return OperandList[N];
177  }
178
179  void Add(const BitCodeAbbrevOp &OpInfo) {
180    OperandList.push_back(OpInfo);
181  }
182};
183} // End llvm namespace
184
185#endif
186