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/IR/FunctionInfo.h"
19 #include "llvm/Support/Endian.h"
20 #include "llvm/Support/ErrorOr.h"
21 #include "llvm/Support/MemoryBuffer.h"
26 class BitstreamWriter;
33 /// Read the header of the specified bitcode buffer and prepare for lazy
34 /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
35 /// lazily load metadata as well. If successful, this moves Buffer. On
36 /// error, this *does not* move Buffer.
37 ErrorOr<std::unique_ptr<Module>>
38 getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
40 DiagnosticHandlerFunction DiagnosticHandler = nullptr,
41 bool ShouldLazyLoadMetadata = false);
43 /// Read the header of the specified stream and prepare for lazy
44 /// deserialization and streaming of function bodies.
45 ErrorOr<std::unique_ptr<Module>> getStreamedBitcodeModule(
46 StringRef Name, std::unique_ptr<DataStreamer> Streamer,
48 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
50 /// Read the header of the specified bitcode buffer and extract just the
51 /// triple information. If successful, this returns a string. On error, this
54 getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
55 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
57 /// Read the header of the specified bitcode buffer and extract just the
58 /// producer string information. If successful, this returns a string. On
59 /// error, this returns "".
60 std::string getBitcodeProducerString(
61 MemoryBufferRef Buffer, LLVMContext &Context,
62 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
64 /// Read the specified bitcode file, returning the module.
65 ErrorOr<std::unique_ptr<Module>>
66 parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
67 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
69 /// Check if the given bitcode buffer contains a function summary block.
70 bool hasFunctionSummary(MemoryBufferRef Buffer,
71 DiagnosticHandlerFunction DiagnosticHandler);
73 /// Parse the specified bitcode buffer, returning the function info index.
74 /// If IsLazy is true, parse the entire function summary into
75 /// the index. Otherwise skip the function summary section, and only create
76 /// an index object with a map from function name to function summary offset.
77 /// The index is used to perform lazy function summary reading later.
78 ErrorOr<std::unique_ptr<FunctionInfoIndex>> getFunctionInfoIndex(
79 MemoryBufferRef Buffer, DiagnosticHandlerFunction DiagnosticHandler,
82 /// This method supports lazy reading of function summary data from the
83 /// combined index during function importing. When reading the combined index
84 /// file, getFunctionInfoIndex is first invoked with IsLazy=true.
85 /// Then this method is called for each function considered for importing,
86 /// to parse the summary information for the given function name into
88 std::error_code readFunctionSummary(
89 MemoryBufferRef Buffer, DiagnosticHandlerFunction DiagnosticHandler,
90 StringRef FunctionName, std::unique_ptr<FunctionInfoIndex> Index);
92 /// \brief Write the specified module to the specified raw output stream.
94 /// For streams where it matters, the given stream should be in "binary"
97 /// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
98 /// Value in \c M. These will be reconstructed exactly when \a M is
101 /// If \c EmitFunctionSummary, emit the function summary index (currently
102 /// for use in ThinLTO optimization).
103 void WriteBitcodeToFile(const Module *M, raw_ostream &Out,
104 bool ShouldPreserveUseListOrder = false,
105 bool EmitFunctionSummary = false);
107 /// Write the specified function summary index to the given raw output stream,
108 /// where it will be written in a new bitcode block. This is used when
109 /// writing the combined index file for ThinLTO.
110 void WriteFunctionSummaryToFile(const FunctionInfoIndex &Index,
113 /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
114 /// for an LLVM IR bitcode wrapper.
116 inline bool isBitcodeWrapper(const unsigned char *BufPtr,
117 const unsigned char *BufEnd) {
118 // See if you can find the hidden message in the magic bytes :-).
119 // (Hint: it's a little-endian encoding.)
120 return BufPtr != BufEnd &&
127 /// isRawBitcode - Return true if the given bytes are the magic bytes for
128 /// raw LLVM IR bitcode (without a wrapper).
130 inline bool isRawBitcode(const unsigned char *BufPtr,
131 const unsigned char *BufEnd) {
132 // These bytes sort of have a hidden message, but it's not in
133 // little-endian this time, and it's a little redundant.
134 return BufPtr != BufEnd &&
141 /// isBitcode - Return true if the given bytes are the magic bytes for
142 /// LLVM IR bitcode, either with or without a wrapper.
144 inline bool isBitcode(const unsigned char *BufPtr,
145 const unsigned char *BufEnd) {
146 return isBitcodeWrapper(BufPtr, BufEnd) ||
147 isRawBitcode(BufPtr, BufEnd);
150 /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
151 /// header for padding or other reasons. The format of this header is:
153 /// struct bc_header {
154 /// uint32_t Magic; // 0x0B17C0DE
155 /// uint32_t Version; // Version, currently always 0.
156 /// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
157 /// uint32_t BitcodeSize; // Size of traditional bitcode file.
158 /// ... potentially other gunk ...
161 /// This function is called when we find a file with a matching magic number.
162 /// In this case, skip down to the subsection of the file that is actually a
164 /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
165 /// contain the whole bitcode file.
166 inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
167 const unsigned char *&BufEnd,
168 bool VerifyBufferSize) {
170 KnownHeaderSize = 4*4, // Size of header we read.
171 OffsetField = 2*4, // Offset in bytes to Offset field.
172 SizeField = 3*4 // Offset in bytes to Size field.
175 // Must contain the header!
176 if (BufEnd-BufPtr < KnownHeaderSize) return true;
178 unsigned Offset = support::endian::read32le(&BufPtr[OffsetField]);
179 unsigned Size = support::endian::read32le(&BufPtr[SizeField]);
181 // Verify that Offset+Size fits in the file.
182 if (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
185 BufEnd = BufPtr+Size;
189 const std::error_category &BitcodeErrorCategory();
190 enum class BitcodeError { InvalidBitcodeSignature = 1, CorruptedBitcode };
191 inline std::error_code make_error_code(BitcodeError E) {
192 return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
195 class BitcodeDiagnosticInfo : public DiagnosticInfo {
200 BitcodeDiagnosticInfo(std::error_code EC, DiagnosticSeverity Severity,
202 void print(DiagnosticPrinter &DP) const override;
203 std::error_code getError() const { return EC; }
205 static bool classof(const DiagnosticInfo *DI) {
206 return DI->getKind() == DK_Bitcode;
210 } // End llvm namespace
213 template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};