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_READERWRITER_H
15 #define LLVM_BITCODE_READERWRITER_H
17 #include "llvm/IR/DiagnosticInfo.h"
18 #include "llvm/Support/Endian.h"
19 #include "llvm/Support/ErrorOr.h"
20 #include "llvm/Support/MemoryBuffer.h"
25 class BitstreamWriter;
32 /// Read the header of the specified bitcode buffer and prepare for lazy
33 /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
34 /// lazily load metadata as well. If successful, this moves Buffer. On
35 /// error, this *does not* move Buffer.
36 ErrorOr<std::unique_ptr<Module>>
37 getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
39 DiagnosticHandlerFunction DiagnosticHandler = nullptr,
40 bool ShouldLazyLoadMetadata = false);
42 /// Read the header of the specified stream and prepare for lazy
43 /// deserialization and streaming of function bodies.
44 ErrorOr<std::unique_ptr<Module>> getStreamedBitcodeModule(
45 StringRef Name, std::unique_ptr<DataStreamer> Streamer,
47 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
49 /// Read the header of the specified bitcode buffer and extract just the
50 /// triple information. If successful, this returns a string. On error, this
53 getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
54 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
56 /// Read the specified bitcode file, returning the module.
57 ErrorOr<std::unique_ptr<Module>>
58 parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
59 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
61 /// \brief Write the specified module to the specified raw output stream.
63 /// For streams where it matters, the given stream should be in "binary"
66 /// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
67 /// Value in \c M. These will be reconstructed exactly when \a M is
69 void WriteBitcodeToFile(const Module *M, raw_ostream &Out,
70 bool ShouldPreserveUseListOrder = false);
72 /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
73 /// for an LLVM IR bitcode wrapper.
75 inline bool isBitcodeWrapper(const unsigned char *BufPtr,
76 const unsigned char *BufEnd) {
77 // See if you can find the hidden message in the magic bytes :-).
78 // (Hint: it's a little-endian encoding.)
79 return BufPtr != BufEnd &&
86 /// isRawBitcode - Return true if the given bytes are the magic bytes for
87 /// raw LLVM IR bitcode (without a wrapper).
89 inline bool isRawBitcode(const unsigned char *BufPtr,
90 const unsigned char *BufEnd) {
91 // These bytes sort of have a hidden message, but it's not in
92 // little-endian this time, and it's a little redundant.
93 return BufPtr != BufEnd &&
100 /// isBitcode - Return true if the given bytes are the magic bytes for
101 /// LLVM IR bitcode, either with or without a wrapper.
103 inline bool isBitcode(const unsigned char *BufPtr,
104 const unsigned char *BufEnd) {
105 return isBitcodeWrapper(BufPtr, BufEnd) ||
106 isRawBitcode(BufPtr, BufEnd);
109 /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
110 /// header for padding or other reasons. The format of this header is:
112 /// struct bc_header {
113 /// uint32_t Magic; // 0x0B17C0DE
114 /// uint32_t Version; // Version, currently always 0.
115 /// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
116 /// uint32_t BitcodeSize; // Size of traditional bitcode file.
117 /// ... potentially other gunk ...
120 /// This function is called when we find a file with a matching magic number.
121 /// In this case, skip down to the subsection of the file that is actually a
123 /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
124 /// contain the whole bitcode file.
125 inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
126 const unsigned char *&BufEnd,
127 bool VerifyBufferSize) {
129 KnownHeaderSize = 4*4, // Size of header we read.
130 OffsetField = 2*4, // Offset in bytes to Offset field.
131 SizeField = 3*4 // Offset in bytes to Size field.
134 // Must contain the header!
135 if (BufEnd-BufPtr < KnownHeaderSize) return true;
137 unsigned Offset = support::endian::read32le(&BufPtr[OffsetField]);
138 unsigned Size = support::endian::read32le(&BufPtr[SizeField]);
140 // Verify that Offset+Size fits in the file.
141 if (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
144 BufEnd = BufPtr+Size;
148 const std::error_category &BitcodeErrorCategory();
149 enum class BitcodeError { InvalidBitcodeSignature = 1, CorruptedBitcode };
150 inline std::error_code make_error_code(BitcodeError E) {
151 return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
154 class BitcodeDiagnosticInfo : public DiagnosticInfo {
159 BitcodeDiagnosticInfo(std::error_code EC, DiagnosticSeverity Severity,
161 void print(DiagnosticPrinter &DP) const override;
162 std::error_code getError() const { return EC; }
164 static bool classof(const DiagnosticInfo *DI) {
165 return DI->getKind() == DK_Bitcode;
169 } // End llvm namespace
172 template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};