1 //===-- ModuleFileExtension.h - Module File Extensions ----------*- 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 #ifndef LLVM_CLANG_SERIALIZATION_MODULEFILEEXTENSION_H 10 #define LLVM_CLANG_SERIALIZATION_MODULEFILEEXTENSION_H 11 12 #include "llvm/ADT/IntrusiveRefCntPtr.h" 13 #include "llvm/Support/ExtensibleRTTI.h" 14 #include "llvm/Support/HashBuilder.h" 15 #include "llvm/Support/MD5.h" 16 #include <memory> 17 #include <string> 18 19 namespace llvm { 20 class BitstreamCursor; 21 class BitstreamWriter; 22 class raw_ostream; 23 } 24 25 namespace clang { 26 27 class ASTReader; 28 class ASTWriter; 29 class Sema; 30 31 namespace serialization { 32 class ModuleFile; 33 } // end namespace serialization 34 35 /// Metadata for a module file extension. 36 struct ModuleFileExtensionMetadata { 37 /// The name used to identify this particular extension block within 38 /// the resulting module file. It should be unique to the particular 39 /// extension, because this name will be used to match the name of 40 /// an extension block to the appropriate reader. 41 std::string BlockName; 42 43 /// The major version of the extension data. 44 unsigned MajorVersion; 45 46 /// The minor version of the extension data. 47 unsigned MinorVersion; 48 49 /// A string containing additional user information that will be 50 /// stored with the metadata. 51 std::string UserInfo; 52 }; 53 54 class ModuleFileExtensionReader; 55 class ModuleFileExtensionWriter; 56 57 /// An abstract superclass that describes a custom extension to the 58 /// module/precompiled header file format. 59 /// 60 /// A module file extension can introduce additional information into 61 /// compiled module files (.pcm) and precompiled headers (.pch) via a 62 /// custom writer that can then be accessed via a custom reader when 63 /// the module file or precompiled header is loaded. 64 /// 65 /// Subclasses must use LLVM RTTI for open class hierarchies. 66 class ModuleFileExtension 67 : public llvm::RTTIExtends<ModuleFileExtension, llvm::RTTIRoot> { 68 public: 69 /// Discriminator for LLVM RTTI. 70 static char ID; 71 72 virtual ~ModuleFileExtension(); 73 74 /// Retrieves the metadata for this module file extension. 75 virtual ModuleFileExtensionMetadata getExtensionMetadata() const = 0; 76 77 /// Hash information about the presence of this extension into the 78 /// module hash. 79 /// 80 /// The module hash is used to distinguish different variants of a module that 81 /// are incompatible. If the presence, absence, or version of the module file 82 /// extension should force the creation of a separate set of module files, 83 /// override this method to combine that distinguishing information into the 84 /// module hash. 85 /// 86 /// The default implementation of this function simply does nothing, so the 87 /// presence/absence of this extension does not distinguish module files. 88 using ExtensionHashBuilder = 89 llvm::HashBuilder<llvm::MD5, llvm::endianness::native>; 90 virtual void hashExtension(ExtensionHashBuilder &HBuilder) const; 91 92 /// Create a new module file extension writer, which will be 93 /// responsible for writing the extension contents into a particular 94 /// module file. 95 virtual std::unique_ptr<ModuleFileExtensionWriter> 96 createExtensionWriter(ASTWriter &Writer) = 0; 97 98 /// Create a new module file extension reader, given the 99 /// metadata read from the block and the cursor into the extension 100 /// block. 101 /// 102 /// May return null to indicate that an extension block with the 103 /// given metadata cannot be read. 104 virtual std::unique_ptr<ModuleFileExtensionReader> 105 createExtensionReader(const ModuleFileExtensionMetadata &Metadata, 106 ASTReader &Reader, serialization::ModuleFile &Mod, 107 const llvm::BitstreamCursor &Stream) = 0; 108 }; 109 110 /// Abstract base class that writes a module file extension block into 111 /// a module file. 112 class ModuleFileExtensionWriter { 113 ModuleFileExtension *Extension; 114 115 protected: 116 ModuleFileExtensionWriter(ModuleFileExtension *Extension) 117 : Extension(Extension) { } 118 119 public: 120 virtual ~ModuleFileExtensionWriter(); 121 122 /// Retrieve the module file extension with which this writer is 123 /// associated. 124 ModuleFileExtension *getExtension() const { return Extension; } 125 126 /// Write the contents of the extension block into the given bitstream. 127 /// 128 /// Responsible for writing the contents of the extension into the 129 /// given stream. All of the contents should be written into custom 130 /// records with IDs >= FIRST_EXTENSION_RECORD_ID. 131 virtual void writeExtensionContents(Sema &SemaRef, 132 llvm::BitstreamWriter &Stream) = 0; 133 }; 134 135 /// Abstract base class that reads a module file extension block from 136 /// a module file. 137 /// 138 /// Subclasses 139 class ModuleFileExtensionReader { 140 ModuleFileExtension *Extension; 141 142 protected: 143 ModuleFileExtensionReader(ModuleFileExtension *Extension) 144 : Extension(Extension) { } 145 146 public: 147 /// Retrieve the module file extension with which this reader is 148 /// associated. 149 ModuleFileExtension *getExtension() const { return Extension; } 150 151 virtual ~ModuleFileExtensionReader(); 152 }; 153 154 } // end namespace clang 155 156 #endif // LLVM_CLANG_SERIALIZATION_MODULEFILEEXTENSION_H 157