1 //===- BitCodes.h - Enum values for the bitcode format ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Chris Lattner and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header Bitcode enum values.
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
16 //===----------------------------------------------------------------------===//
18 #ifndef LLVM_BITCODE_BITCODES_H
19 #define LLVM_BITCODE_BITCODES_H
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/Support/DataTypes.h"
28 BlockIDWidth = 8, // We use VBR-8 for block IDs.
29 CodeLenWidth = 4, // Codelen are VBR-4.
30 BlockSizeWidth = 32 // BlockSize up to 2^32 32-bit words = 32GB per block.
33 // The standard abbrev namespace always has a way to exit a block, enter a
34 // nested block, define abbrevs, and define an unabbreviated record.
36 END_BLOCK = 0, // Must be zero to guarantee termination for broken bitcode.
39 /// DEFINE_ABBREV - Defines an abbrev for the current block. It consists
40 /// of a vbr5 for # operand infos. Each operand info is emitted with a
41 /// single bit to indicate if it is a literal encoding. If so, the value is
42 /// emitted with a vbr8. If not, the encoding is emitted as 3 bits followed
43 /// by the info value as a vbr5 if needed.
46 // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
47 // a vbr6 for the # operands, followed by vbr6's for each operand.
50 // This is not a code, this is a marker for the first abbrev assignment.
51 FIRST_APPLICATION_ABBREV = 4
54 /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
55 /// block, which contains metadata about other blocks in the file.
56 enum StandardBlockIDs {
57 /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
58 /// standard abbrevs that should be available to all blocks of a specified
60 BLOCKINFO_BLOCK_ID = 0,
62 // Block IDs 1-7 are reserved for future expansion.
63 FIRST_APPLICATION_BLOCKID = 8
66 /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
69 BLOCKINFO_CODE_SETBID = 1, // SETBID: [blockid#]
70 BLOCKINFO_CODE_ABBREV = 2 // ABBREV: [standard abbrev encoding]
71 // BLOCKNAME: give string name to block, if desired.
74 } // End bitc namespace
76 /// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
77 /// This is actually a union of two different things:
78 /// 1. It could be a literal integer value ("the operand is always 17").
79 /// 2. It could be an encoding specification ("this operand encoded like so").
81 class BitCodeAbbrevOp {
82 uint64_t Val; // A literal value or data for an encoding.
83 bool IsLiteral : 1; // Indicate whether this is a literal value or not.
84 unsigned Enc : 3; // The encoding to use.
87 FixedWidth = 1, // A fixed with field, Val specifies number of bits.
88 VBR = 2 // A VBR field where Val specifies the width of each chunk.
91 BitCodeAbbrevOp(uint64_t V) : Val(V), IsLiteral(true) {}
92 BitCodeAbbrevOp(Encoding E, uint64_t Data)
93 : Val(Data), IsLiteral(false), Enc(E) {}
95 bool isLiteral() const { return IsLiteral; }
96 bool isEncoding() const { return !IsLiteral; }
98 // Accessors for literals.
99 uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }
101 // Accessors for encoding info.
102 Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
103 uint64_t getEncodingData() const { assert(isEncoding()); return Val; }
105 bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
106 static bool hasEncodingData(Encoding E) {
111 /// BitCodeAbbrev - This class represents an abbreviation record. An
112 /// abbreviation allows a complex record that has redundancy to be stored in a
113 /// specialized format instead of the fully-general, fully-vbr, format.
114 class BitCodeAbbrev {
115 SmallVector<BitCodeAbbrevOp, 8> OperandList;
116 unsigned char RefCount; // Number of things using this.
119 BitCodeAbbrev() : RefCount(1) {}
121 void addRef() { ++RefCount; }
122 void dropRef() { if (--RefCount == 0) delete this; }
124 unsigned getNumOperandInfos() const { return OperandList.size(); }
125 const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
126 return OperandList[N];
129 void Add(const BitCodeAbbrevOp &OpInfo) {
130 OperandList.push_back(OpInfo);
133 } // End llvm namespace