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
24 class BitstreamWriter;
28 /// getBitcodeModuleProvider - Read the header of the specified bitcode buffer
29 /// and prepare for lazy deserialization of function bodies. If successful,
30 /// this takes ownership of 'buffer' and returns a non-null pointer. On
31 /// error, this returns null, *does not* take ownership of Buffer, and fills
32 /// in *ErrMsg with an error description if ErrMsg is non-null.
33 ModuleProvider *getBitcodeModuleProvider(MemoryBuffer *Buffer,
35 std::string *ErrMsg = 0);
37 /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
38 /// If an error occurs, this returns null and fills in *ErrMsg if it is
39 /// non-null. This method *never* takes ownership of Buffer.
40 Module *ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,
41 std::string *ErrMsg = 0);
43 /// WriteBitcodeToFile - Write the specified module to the specified
44 /// raw output stream.
45 void WriteBitcodeToFile(const Module *M, raw_ostream &Out);
47 /// WriteBitcodeToStream - Write the specified module to the specified
48 /// raw output stream.
49 void WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream);
51 /// createBitcodeWriterPass - Create and return a pass that writes the module
52 /// to the specified ostream.
53 ModulePass *createBitcodeWriterPass(raw_ostream &Str);
56 /// isBitcodeWrapper - Return true fi this is a wrapper for LLVM IR bitcode
58 static bool inline isBitcodeWrapper(unsigned char *BufPtr,
59 unsigned char *BufEnd) {
60 return (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 &&
61 BufPtr[2] == 0x17 && BufPtr[3] == 0x0B);
64 /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
65 /// header for padding or other reasons. The format of this header is:
67 /// struct bc_header {
68 /// uint32_t Magic; // 0x0B17C0DE
69 /// uint32_t Version; // Version, currently always 0.
70 /// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
71 /// uint32_t BitcodeSize; // Size of traditional bitcode file.
72 /// ... potentially other gunk ...
75 /// This function is called when we find a file with a matching magic number.
76 /// In this case, skip down to the subsection of the file that is actually a
78 static inline bool SkipBitcodeWrapperHeader(unsigned char *&BufPtr,
79 unsigned char *&BufEnd) {
81 KnownHeaderSize = 4*4, // Size of header we read.
82 OffsetField = 2*4, // Offset in bytes to Offset field.
83 SizeField = 3*4 // Offset in bytes to Size field.
86 // Must contain the header!
87 if (BufEnd-BufPtr < KnownHeaderSize) return true;
89 unsigned Offset = ( BufPtr[OffsetField ] |
90 (BufPtr[OffsetField+1] << 8) |
91 (BufPtr[OffsetField+2] << 16) |
92 (BufPtr[OffsetField+3] << 24));
93 unsigned Size = ( BufPtr[SizeField ] |
94 (BufPtr[SizeField +1] << 8) |
95 (BufPtr[SizeField +2] << 16) |
96 (BufPtr[SizeField +3] << 24));
98 // Verify that Offset+Size fits in the file.
99 if (Offset+Size > unsigned(BufEnd-BufPtr))
102 BufEnd = BufPtr+Size;
105 } // End llvm namespace