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//===-- llvm/Bitcode/ReaderWriter.h - Bitcode reader/writers ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header defines interfaces to read and write LLVM bitcode files/streams.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_BITCODE_H
#define LLVM_BITCODE_H
#include <iosfwd>
#include <string>
namespace llvm {
class Module;
class ModuleProvider;
class MemoryBuffer;
class ModulePass;
class BitstreamWriter;
class LLVMContext;
class raw_ostream;
/// getBitcodeModuleProvider - Read the header of the specified bitcode buffer
/// and prepare for lazy deserialization of function bodies. If successful,
/// this takes ownership of 'buffer' and returns a non-null pointer. On
/// error, this returns null, *does not* take ownership of Buffer, and fills
/// in *ErrMsg with an error description if ErrMsg is non-null.
ModuleProvider *getBitcodeModuleProvider(MemoryBuffer *Buffer,
LLVMContext* Context,
std::string *ErrMsg = 0);
/// ParseBitcodeFile - Read the specified bitcode file, returning the module.
/// If an error occurs, this returns null and fills in *ErrMsg if it is
/// non-null. This method *never* takes ownership of Buffer.
Module *ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext* Context,
std::string *ErrMsg = 0);
/// WriteBitcodeToFile - Write the specified module to the specified output
/// stream.
void WriteBitcodeToFile(const Module *M, std::ostream &Out);
/// WriteBitcodeToFile - Write the specified module to the specified
/// raw output stream.
void WriteBitcodeToFile(const Module *M, raw_ostream &Out);
/// WriteBitcodeToStream - Write the specified module to the specified
/// raw output stream.
void WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream);
/// CreateBitcodeWriterPass - Create and return a pass that writes the module
/// to the specified ostream.
ModulePass *CreateBitcodeWriterPass(std::ostream &Str);
/// createBitcodeWriterPass - Create and return a pass that writes the module
/// to the specified ostream.
ModulePass *createBitcodeWriterPass(raw_ostream &Str);
/// isBitcodeWrapper - Return true fi this is a wrapper for LLVM IR bitcode
/// files.
static bool inline isBitcodeWrapper(unsigned char *BufPtr,
unsigned char *BufEnd) {
return (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 &&
BufPtr[2] == 0x17 && BufPtr[3] == 0x0B);
}
/// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
/// header for padding or other reasons. The format of this header is:
///
/// struct bc_header {
/// uint32_t Magic; // 0x0B17C0DE
/// uint32_t Version; // Version, currently always 0.
/// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
/// uint32_t BitcodeSize; // Size of traditional bitcode file.
/// ... potentially other gunk ...
/// };
///
/// This function is called when we find a file with a matching magic number.
/// In this case, skip down to the subsection of the file that is actually a
/// BC file.
static inline bool SkipBitcodeWrapperHeader(unsigned char *&BufPtr,
unsigned char *&BufEnd) {
enum {
KnownHeaderSize = 4*4, // Size of header we read.
OffsetField = 2*4, // Offset in bytes to Offset field.
SizeField = 3*4 // Offset in bytes to Size field.
};
// Must contain the header!
if (BufEnd-BufPtr < KnownHeaderSize) return true;
unsigned Offset = ( BufPtr[OffsetField ] |
(BufPtr[OffsetField+1] << 8) |
(BufPtr[OffsetField+2] << 16) |
(BufPtr[OffsetField+3] << 24));
unsigned Size = ( BufPtr[SizeField ] |
(BufPtr[SizeField +1] << 8) |
(BufPtr[SizeField +2] << 16) |
(BufPtr[SizeField +3] << 24));
// Verify that Offset+Size fits in the file.
if (Offset+Size > unsigned(BufEnd-BufPtr))
return true;
BufPtr += Offset;
BufEnd = BufPtr+Size;
return false;
}
} // End llvm namespace
#endif
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