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 specified bitcode file, returning the module.
58 ErrorOr<std::unique_ptr<Module>>
59 parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
60 DiagnosticHandlerFunction DiagnosticHandler = nullptr);
62 /// Check if the given bitcode buffer contains a function summary block.
63 bool hasFunctionSummary(MemoryBufferRef Buffer, LLVMContext &Context,
64 DiagnosticHandlerFunction DiagnosticHandler);
66 /// Parse the specified bitcode buffer, returning the function info index.
67 /// If ExportingModule is true, check for functions in the index from this
68 /// module when the combined index is built during parsing and set flag.
69 /// If IsLazy is true, parse the entire function summary into
70 /// the index. Otherwise skip the function summary section, and only create
71 /// an index object with a map from function name to function summary offset.
72 /// The index is used to perform lazy function summary reading later.
73 ErrorOr<std::unique_ptr<FunctionInfoIndex>>
74 getFunctionInfoIndex(MemoryBufferRef Buffer, LLVMContext &Context,
75 DiagnosticHandlerFunction DiagnosticHandler,
76 const Module *ExportingModule = nullptr,
79 /// This method supports lazy reading of function summary data from the
80 /// combined index during function importing. When reading the combined index
81 /// file, getFunctionInfoIndex is first invoked with IsLazy=true.
82 /// Then this method is called for each function considered for importing,
83 /// to parse the summary information for the given function name into
86 readFunctionSummary(MemoryBufferRef Buffer, LLVMContext &Context,
87 DiagnosticHandlerFunction DiagnosticHandler,
88 StringRef FunctionName,
89 std::unique_ptr<FunctionInfoIndex> Index);
91 /// \brief Write the specified module to the specified raw output stream.
93 /// For streams where it matters, the given stream should be in "binary"
96 /// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
97 /// Value in \c M. These will be reconstructed exactly when \a M is
100 /// If \c EmitFunctionSummary, emit the function summary index (currently
101 /// for use in ThinLTO optimization).
102 void WriteBitcodeToFile(const Module *M, raw_ostream &Out,
103 bool ShouldPreserveUseListOrder = false,
104 bool EmitFunctionSummary = false);
106 /// Write the specified function summary index to the given raw output stream,
107 /// where it will be written in a new bitcode block. This is used when
108 /// writing the combined index file for ThinLTO.
109 void WriteFunctionSummaryToFile(const FunctionInfoIndex &Index,
112 /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
113 /// for an LLVM IR bitcode wrapper.
115 inline bool isBitcodeWrapper(const unsigned char *BufPtr,
116 const unsigned char *BufEnd) {
117 // See if you can find the hidden message in the magic bytes :-).
118 // (Hint: it's a little-endian encoding.)
119 return BufPtr != BufEnd &&
126 /// isRawBitcode - Return true if the given bytes are the magic bytes for
127 /// raw LLVM IR bitcode (without a wrapper).
129 inline bool isRawBitcode(const unsigned char *BufPtr,
130 const unsigned char *BufEnd) {
131 // These bytes sort of have a hidden message, but it's not in
132 // little-endian this time, and it's a little redundant.
133 return BufPtr != BufEnd &&
140 /// isBitcode - Return true if the given bytes are the magic bytes for
141 /// LLVM IR bitcode, either with or without a wrapper.
143 inline bool isBitcode(const unsigned char *BufPtr,
144 const unsigned char *BufEnd) {
145 return isBitcodeWrapper(BufPtr, BufEnd) ||
146 isRawBitcode(BufPtr, BufEnd);
149 /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
150 /// header for padding or other reasons. The format of this header is:
152 /// struct bc_header {
153 /// uint32_t Magic; // 0x0B17C0DE
154 /// uint32_t Version; // Version, currently always 0.
155 /// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
156 /// uint32_t BitcodeSize; // Size of traditional bitcode file.
157 /// ... potentially other gunk ...
160 /// This function is called when we find a file with a matching magic number.
161 /// In this case, skip down to the subsection of the file that is actually a
163 /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
164 /// contain the whole bitcode file.
165 inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
166 const unsigned char *&BufEnd,
167 bool VerifyBufferSize) {
169 KnownHeaderSize = 4*4, // Size of header we read.
170 OffsetField = 2*4, // Offset in bytes to Offset field.
171 SizeField = 3*4 // Offset in bytes to Size field.
174 // Must contain the header!
175 if (BufEnd-BufPtr < KnownHeaderSize) return true;
177 unsigned Offset = support::endian::read32le(&BufPtr[OffsetField]);
178 unsigned Size = support::endian::read32le(&BufPtr[SizeField]);
180 // Verify that Offset+Size fits in the file.
181 if (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
184 BufEnd = BufPtr+Size;
188 const std::error_category &BitcodeErrorCategory();
189 enum class BitcodeError { InvalidBitcodeSignature = 1, CorruptedBitcode };
190 inline std::error_code make_error_code(BitcodeError E) {
191 return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
194 class BitcodeDiagnosticInfo : public DiagnosticInfo {
199 BitcodeDiagnosticInfo(std::error_code EC, DiagnosticSeverity Severity,
201 void print(DiagnosticPrinter &DP) const override;
202 std::error_code getError() const { return EC; }
204 static bool classof(const DiagnosticInfo *DI) {
205 return DI->getKind() == DK_Bitcode;
209 } // End llvm namespace
212 template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};