LLVM 19.0.0git
BitcodeWriter.h
Go to the documentation of this file.
1//===- llvm/Bitcode/BitcodeWriter.h - Bitcode writers -----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This header defines interfaces to write LLVM bitcode files/streams.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_BITCODE_BITCODEWRITER_H
14#define LLVM_BITCODE_BITCODEWRITER_H
15
16#include "llvm/ADT/StringRef.h"
21#include <map>
22#include <memory>
23#include <string>
24#include <vector>
25
26namespace llvm {
27
28class BitstreamWriter;
29class Module;
30class raw_ostream;
31
34 std::unique_ptr<BitstreamWriter> Stream;
35
37
38 // Owns any strings created by the irsymtab writer until we create the
39 // string table.
40 BumpPtrAllocator Alloc;
41
42 bool WroteStrtab = false, WroteSymtab = false;
43
44 void writeBlob(unsigned Block, unsigned Record, StringRef Blob);
45
46 std::vector<Module *> Mods;
47
48 public:
49 /// Create a BitcodeWriter that writes to Buffer.
51
53
54 /// Attempt to write a symbol table to the bitcode file. This must be called
55 /// at most once after all modules have been written.
56 ///
57 /// A reader does not require a symbol table to interpret a bitcode file;
58 /// the symbol table is needed only to improve link-time performance. So
59 /// this function may decide not to write a symbol table. It may so decide
60 /// if, for example, the target is unregistered or the IR is malformed.
61 void writeSymtab();
62
63 /// Write the bitcode file's string table. This must be called exactly once
64 /// after all modules and the optional symbol table have been written.
65 void writeStrtab();
66
67 /// Copy the string table for another module into this bitcode file. This
68 /// should be called after copying the module itself into the bitcode file.
69 void copyStrtab(StringRef Strtab);
70
71 /// Write the specified module to the buffer specified at construction time.
72 ///
73 /// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
74 /// Value in \c M. These will be reconstructed exactly when \a M is
75 /// deserialized.
76 ///
77 /// If \c Index is supplied, the bitcode will contain the summary index
78 /// (currently for use in ThinLTO optimization).
79 ///
80 /// \p GenerateHash enables hashing the Module and including the hash in the
81 /// bitcode (currently for use in ThinLTO incremental build).
82 ///
83 /// If \p ModHash is non-null, when GenerateHash is true, the resulting
84 /// hash is written into ModHash. When GenerateHash is false, that value
85 /// is used as the hash instead of computing from the generated bitcode.
86 /// Can be used to produce the same module hash for a minimized bitcode
87 /// used just for the thin link as in the regular full bitcode that will
88 /// be used in the backend.
89 void writeModule(const Module &M, bool ShouldPreserveUseListOrder = false,
90 const ModuleSummaryIndex *Index = nullptr,
91 bool GenerateHash = false, ModuleHash *ModHash = nullptr);
92
93 /// Write the specified thin link bitcode file (i.e., the minimized bitcode
94 /// file) to the buffer specified at construction time. The thin link
95 /// bitcode file is used for thin link, and it only contains the necessary
96 /// information for thin link.
97 ///
98 /// ModHash is for use in ThinLTO incremental build, generated while the
99 /// IR bitcode file writing.
101 const ModuleHash &ModHash);
102
103 void writeIndex(
105 const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex);
106 };
107
108 /// Write the specified module to the specified raw output stream.
109 ///
110 /// For streams where it matters, the given stream should be in "binary"
111 /// mode.
112 ///
113 /// If \c ShouldPreserveUseListOrder, encode the use-list order for each \a
114 /// Value in \c M. These will be reconstructed exactly when \a M is
115 /// deserialized.
116 ///
117 /// If \c Index is supplied, the bitcode will contain the summary index
118 /// (currently for use in ThinLTO optimization).
119 ///
120 /// \p GenerateHash enables hashing the Module and including the hash in the
121 /// bitcode (currently for use in ThinLTO incremental build).
122 ///
123 /// If \p ModHash is non-null, when GenerateHash is true, the resulting
124 /// hash is written into ModHash. When GenerateHash is false, that value
125 /// is used as the hash instead of computing from the generated bitcode.
126 /// Can be used to produce the same module hash for a minimized bitcode
127 /// used just for the thin link as in the regular full bitcode that will
128 /// be used in the backend.
129 void WriteBitcodeToFile(const Module &M, raw_ostream &Out,
130 bool ShouldPreserveUseListOrder = false,
131 const ModuleSummaryIndex *Index = nullptr,
132 bool GenerateHash = false,
133 ModuleHash *ModHash = nullptr);
134
135 /// Write the specified thin link bitcode file (i.e., the minimized bitcode
136 /// file) to the given raw output stream, where it will be written in a new
137 /// bitcode block. The thin link bitcode file is used for thin link, and it
138 /// only contains the necessary information for thin link.
139 ///
140 /// ModHash is for use in ThinLTO incremental build, generated while the IR
141 /// bitcode file writing.
144 const ModuleHash &ModHash);
145
146 /// Write the specified module summary index to the given raw output stream,
147 /// where it will be written in a new bitcode block. This is used when
148 /// writing the combined index file for ThinLTO. When writing a subset of the
149 /// index for a distributed backend, provide the \p ModuleToSummariesForIndex
150 /// map.
152 const std::map<std::string, GVSummaryMapTy>
153 *ModuleToSummariesForIndex = nullptr);
154
155 /// If EmbedBitcode is set, save a copy of the llvm IR as data in the
156 /// __LLVM,__bitcode section (.llvmbc on non-MacOS).
157 /// If available, pass the serialized module via the Buf parameter. If not,
158 /// pass an empty (default-initialized) MemoryBufferRef, and the serialization
159 /// will be handled by this API. The same behavior happens if the provided Buf
160 /// is not bitcode (i.e. if it's invalid data or even textual LLVM assembly).
161 /// If EmbedCmdline is set, the command line is also exported in
162 /// the corresponding section (__LLVM,_cmdline / .llvmcmd) - even if CmdArgs
163 /// were empty.
165 bool EmbedCmdline,
166 const std::vector<uint8_t> &CmdArgs);
167
168} // end namespace llvm
169
170#endif // LLVM_BITCODE_BITCODEWRITER_H
This file defines the BumpPtrAllocator interface.
static cl::opt< LTOBitcodeEmbedding > EmbedBitcode("lto-embed-bitcode", cl::init(LTOBitcodeEmbedding::DoNotEmbed), cl::values(clEnumValN(LTOBitcodeEmbedding::DoNotEmbed, "none", "Do not embed"), clEnumValN(LTOBitcodeEmbedding::EmbedOptimized, "optimized", "Embed after all optimization passes"), clEnumValN(LTOBitcodeEmbedding::EmbedPostMergePreOptimized, "post-merge-pre-opt", "Embed post merge, but before optimizations")), cl::desc("Embed LLVM bitcode in object files produced by LTO"))
Machine Check Debug Module
ModuleSummaryIndex.h This file contains the declarations the classes that hold the module index and s...
void writeThinLinkBitcode(const Module &M, const ModuleSummaryIndex &Index, const ModuleHash &ModHash)
Write the specified thin link bitcode file (i.e., the minimized bitcode file) to the buffer specified...
void copyStrtab(StringRef Strtab)
Copy the string table for another module into this bitcode file.
void writeStrtab()
Write the bitcode file's string table.
void writeSymtab()
Attempt to write a symbol table to the bitcode file.
void writeIndex(const ModuleSummaryIndex *Index, const std::map< std::string, GVSummaryMapTy > *ModuleToSummariesForIndex)
void writeModule(const Module &M, bool ShouldPreserveUseListOrder=false, const ModuleSummaryIndex *Index=nullptr, bool GenerateHash=false, ModuleHash *ModHash=nullptr)
Write the specified module to the buffer specified at construction time.
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:66
Class to hold module path string table and global value map, and encapsulate methods for operating on...
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: SmallVector.h:586
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
Utility for building string tables with deduplicated suffixes.
A raw_ostream of a file for reading/writing/seeking.
Definition: raw_ostream.h:627
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
void WriteBitcodeToFile(const Module &M, raw_ostream &Out, bool ShouldPreserveUseListOrder=false, const ModuleSummaryIndex *Index=nullptr, bool GenerateHash=false, ModuleHash *ModHash=nullptr)
Write the specified module to the specified raw output stream.
void writeIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out, const std::map< std::string, GVSummaryMapTy > *ModuleToSummariesForIndex=nullptr)
Write the specified module summary index to the given raw output stream, where it will be written in ...
void writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out, const ModuleSummaryIndex &Index, const ModuleHash &ModHash)
Write the specified thin link bitcode file (i.e., the minimized bitcode file) to the given raw output...
void embedBitcodeInModule(Module &M, MemoryBufferRef Buf, bool EmbedBitcode, bool EmbedCmdline, const std::vector< uint8_t > &CmdArgs)
If EmbedBitcode is set, save a copy of the llvm IR as data in the __LLVM,__bitcode section (....
std::array< uint32_t, 5 > ModuleHash
160 bits SHA1