1 //===-- llvm/Bitcode/ReaderWriter.h - Bitcode reader/writers ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header defines interfaces to read and write LLVM bitcode files/streams.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_BITCODE_H
15 #define LLVM_BITCODE_H
25 class BitstreamWriter;
29 /// getBitcodeModuleProvider - Read the header of the specified bitcode buffer
30 /// and prepare for lazy deserialization of function bodies. If successful,
31 /// this takes ownership of 'buffer' and returns a non-null pointer. On
32 /// error, this returns null, *does not* take ownership of Buffer, and fills
33 /// in *ErrMsg with an error description if ErrMsg is non-null.
34 ModuleProvider *getBitcodeModuleProvider(MemoryBuffer *Buffer,
36 std::string *ErrMsg = 0);
38 /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
39 /// If an error occurs, this returns null and fills in *ErrMsg if it is
40 /// non-null. This method *never* takes ownership of Buffer.
41 Module *ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,
42 std::string *ErrMsg = 0);
44 /// WriteBitcodeToFile - Write the specified module to the specified output
46 void WriteBitcodeToFile(const Module *M, std::ostream &Out);
48 /// WriteBitcodeToFile - Write the specified module to the specified
49 /// raw output stream.
50 void WriteBitcodeToFile(const Module *M, raw_ostream &Out);
52 /// WriteBitcodeToStream - Write the specified module to the specified
53 /// raw output stream.
54 void WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream);
56 /// CreateBitcodeWriterPass - Create and return a pass that writes the module
57 /// to the specified ostream.
58 ModulePass *CreateBitcodeWriterPass(std::ostream &Str);
60 /// createBitcodeWriterPass - Create and return a pass that writes the module
61 /// to the specified ostream.
62 ModulePass *createBitcodeWriterPass(raw_ostream &Str);
65 /// isBitcodeWrapper - Return true fi this is a wrapper for LLVM IR bitcode
67 static bool inline isBitcodeWrapper(unsigned char *BufPtr,
68 unsigned char *BufEnd) {
69 return (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 &&
70 BufPtr[2] == 0x17 && BufPtr[3] == 0x0B);
73 /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
74 /// header for padding or other reasons. The format of this header is:
76 /// struct bc_header {
77 /// uint32_t Magic; // 0x0B17C0DE
78 /// uint32_t Version; // Version, currently always 0.
79 /// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
80 /// uint32_t BitcodeSize; // Size of traditional bitcode file.
81 /// ... potentially other gunk ...
84 /// This function is called when we find a file with a matching magic number.
85 /// In this case, skip down to the subsection of the file that is actually a
87 static inline bool SkipBitcodeWrapperHeader(unsigned char *&BufPtr,
88 unsigned char *&BufEnd) {
90 KnownHeaderSize = 4*4, // Size of header we read.
91 OffsetField = 2*4, // Offset in bytes to Offset field.
92 SizeField = 3*4 // Offset in bytes to Size field.
95 // Must contain the header!
96 if (BufEnd-BufPtr < KnownHeaderSize) return true;
98 unsigned Offset = ( BufPtr[OffsetField ] |
99 (BufPtr[OffsetField+1] << 8) |
100 (BufPtr[OffsetField+2] << 16) |
101 (BufPtr[OffsetField+3] << 24));
102 unsigned Size = ( BufPtr[SizeField ] |
103 (BufPtr[SizeField +1] << 8) |
104 (BufPtr[SizeField +2] << 16) |
105 (BufPtr[SizeField +3] << 24));
107 // Verify that Offset+Size fits in the file.
108 if (Offset+Size > unsigned(BufEnd-BufPtr))
111 BufEnd = BufPtr+Size;
114 } // End llvm namespace