//===-- 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_READERWRITER_H
#define LLVM_BITCODE_READERWRITER_H
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MemoryBuffer.h"
#include <memory>
#include <string>
namespace llvm {
class BitstreamWriter;
class DataStreamer;
class LLVMContext;
class Module;
class ModulePass;
class raw_ostream;
/// Read the header of the specified bitcode buffer and prepare for lazy
/// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
/// lazily load metadata as well. If successful, this moves Buffer. On
/// error, this *does not* move Buffer.
ErrorOr<Module *>
getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
LLVMContext &Context,
DiagnosticHandlerFunction DiagnosticHandler = nullptr,
bool ShouldLazyLoadMetadata = false);
/// Read the header of the specified stream and prepare for lazy
/// deserialization and streaming of function bodies.
ErrorOr<std::unique_ptr<Module>> getStreamedBitcodeModule(
StringRef Name, DataStreamer *Streamer, LLVMContext &Context,
DiagnosticHandlerFunction DiagnosticHandler = nullptr);
/// Read the header of the specified bitcode buffer and extract just the
/// triple information. If successful, this returns a string. On error, this
/// returns "".
std::string
getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
DiagnosticHandlerFunction DiagnosticHandler = nullptr);
/// Read the specified bitcode file, returning the module.
ErrorOr<Module *>
parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
DiagnosticHandlerFunction DiagnosticHandler = nullptr);
/// \brief Write the specified module to the specified raw output stream.
///
/// For streams where it matters, the given stream should be in "binary"
/// mode.
///
/// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
/// Value in \c M. These will be reconstructed exactly when \a M is
/// deserialized.
void WriteBitcodeToFile(const Module *M, raw_ostream &Out,
bool ShouldPreserveUseListOrder = false);
/// isBitcodeWrapper - Return true if the given bytes are the magic bytes
/// for an LLVM IR bitcode wrapper.
///
inline bool isBitcodeWrapper(const unsigned char *BufPtr,
const unsigned char *BufEnd) {
// See if you can find the hidden message in the magic bytes :-).
// (Hint: it's a little-endian encoding.)
return BufPtr != BufEnd &&
BufPtr[0] == 0xDE &&
BufPtr[1] == 0xC0 &&
BufPtr[2] == 0x17 &&
BufPtr[3] == 0x0B;
}
/// isRawBitcode - Return true if the given bytes are the magic bytes for
/// raw LLVM IR bitcode (without a wrapper).
///
inline bool isRawBitcode(const unsigned char *BufPtr,
const unsigned char *BufEnd) {
// These bytes sort of have a hidden message, but it's not in
// little-endian this time, and it's a little redundant.
return BufPtr != BufEnd &&
BufPtr[0] == 'B' &&
BufPtr[1] == 'C' &&
BufPtr[2] == 0xc0 &&
BufPtr[3] == 0xde;
}
/// isBitcode - Return true if the given bytes are the magic bytes for
/// LLVM IR bitcode, either with or without a wrapper.
///
inline bool isBitcode(const unsigned char *BufPtr,
const unsigned char *BufEnd) {
return isBitcodeWrapper(BufPtr, BufEnd) ||
isRawBitcode(BufPtr, BufEnd);
}
/// 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.
/// If 'VerifyBufferSize' is true, check that the buffer is large enough to
/// contain the whole bitcode file.
inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
const unsigned char *&BufEnd,
bool VerifyBufferSize) {
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 (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
return true;
BufPtr += Offset;
BufEnd = BufPtr+Size;
return false;
}
const std::error_category &BitcodeErrorCategory();
enum class BitcodeError { InvalidBitcodeSignature, CorruptedBitcode };
inline std::error_code make_error_code(BitcodeError E) {
return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
}
class BitcodeDiagnosticInfo : public DiagnosticInfo {
const Twine &Msg;
std::error_code EC;
public:
BitcodeDiagnosticInfo(std::error_code EC, DiagnosticSeverity Severity,
const Twine &Msg);
void print(DiagnosticPrinter &DP) const override;
std::error_code getError() const { return EC; };
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() == DK_Bitcode;
}
};
} // End llvm namespace
namespace std {
template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};
}
#endif
