Modules: Rename MemoryBufferCache to InMemoryModuleCache

Change MemoryBufferCache to InMemoryModuleCache, moving it from Basic to
Serialization.  Another patch will start using it to manage module build
more explicitly, but this is split out because it's mostly mechanical.

Because of the move to Serialization we can no longer abuse the
Preprocessor to forward it to the ASTReader.  Besides the rename and
file move, that means Preprocessor::Preprocessor has one fewer parameter
and ASTReader::ASTReader has one more.

llvm-svn: 355777

Author: dexonsmith

clang/include/clang/Frontend/ASTUnit.h

@@ -71,7 +71,7 @@ class FileManager;
 class FrontendAction;
 class HeaderSearch;
 class InputKind;
-class MemoryBufferCache;
+class InMemoryModuleCache;
 class PCHContainerOperations;
 class PCHContainerReader;
 class Preprocessor;
@@ -107,7 +107,7 @@ class ASTUnit {
   IntrusiveRefCntPtr<DiagnosticsEngine>   Diagnostics;
   IntrusiveRefCntPtr<FileManager>         FileMgr;
   IntrusiveRefCntPtr<SourceManager>       SourceMgr;
-  IntrusiveRefCntPtr<MemoryBufferCache>   PCMCache;
+  IntrusiveRefCntPtr<InMemoryModuleCache> ModuleCache;
   std::unique_ptr<HeaderSearch>           HeaderInfo;
   IntrusiveRefCntPtr<TargetInfo>          Target;
   std::shared_ptr<Preprocessor>           PP;

clang/include/clang/Frontend/CompilerInstance.h

@@ -44,7 +44,7 @@ class ExternalASTSource;
 class FileEntry;
 class FileManager;
 class FrontendAction;
-class MemoryBufferCache;
+class InMemoryModuleCache;
 class Module;
 class Preprocessor;
 class Sema;
@@ -92,7 +92,7 @@ class CompilerInstance : public ModuleLoader {
   IntrusiveRefCntPtr<SourceManager> SourceMgr;
 
   /// The cache of PCM files.
-  IntrusiveRefCntPtr<MemoryBufferCache> PCMCache;
+  IntrusiveRefCntPtr<InMemoryModuleCache> ModuleCache;
 
   /// The preprocessor.
   std::shared_ptr<Preprocessor> PP;
@@ -192,7 +192,7 @@ class CompilerInstance : public ModuleLoader {
   explicit CompilerInstance(
       std::shared_ptr<PCHContainerOperations> PCHContainerOps =
           std::make_shared<PCHContainerOperations>(),
-      MemoryBufferCache *SharedPCMCache = nullptr);
+      InMemoryModuleCache *SharedModuleCache = nullptr);
   ~CompilerInstance() override;
 
   /// @name High-Level Operations
@@ -671,7 +671,8 @@ class CompilerInstance : public ModuleLoader {
   /// \return - The new object on success, or null on failure.
   static IntrusiveRefCntPtr<ASTReader> createPCHExternalASTSource(
       StringRef Path, StringRef Sysroot, bool DisablePCHValidation,
-      bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
+      bool AllowPCHWithCompilerErrors, Preprocessor &PP,
+      InMemoryModuleCache &ModuleCache, ASTContext &Context,
       const PCHContainerReader &PCHContainerRdr,
       ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
       DependencyFileGenerator *DependencyFile,
@@ -813,7 +814,7 @@ class CompilerInstance : public ModuleLoader {
 
   void setExternalSemaSource(IntrusiveRefCntPtr<ExternalSemaSource> ESS);
 
-  MemoryBufferCache &getPCMCache() const { return *PCMCache; }
+  InMemoryModuleCache &getModuleCache() const { return *ModuleCache; }
 };
 
 } // end namespace clang

clang/include/clang/Lex/Preprocessor.h

@@ -71,7 +71,6 @@ class FileEntry;
 class FileManager;
 class HeaderSearch;
 class MacroArgs;
-class MemoryBufferCache;
 class PragmaHandler;
 class PragmaNamespace;
 class PreprocessingRecord;
@@ -132,7 +131,6 @@ class Preprocessor {
   const TargetInfo *AuxTarget = nullptr;
   FileManager       &FileMgr;
   SourceManager     &SourceMgr;
-  MemoryBufferCache &PCMCache;
   std::unique_ptr<ScratchBuffer> ScratchBuf;
   HeaderSearch      &HeaderInfo;
   ModuleLoader      &TheModuleLoader;
@@ -779,7 +777,6 @@ class Preprocessor {
 public:
   Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
                DiagnosticsEngine &diags, LangOptions &opts, SourceManager &SM,
-               MemoryBufferCache &PCMCache,
                HeaderSearch &Headers, ModuleLoader &TheModuleLoader,
                IdentifierInfoLookup *IILookup = nullptr,
                bool OwnsHeaderSearch = false,
@@ -819,7 +816,6 @@ class Preprocessor {
   const TargetInfo *getAuxTargetInfo() const { return AuxTarget; }
   FileManager &getFileManager() const { return FileMgr; }
   SourceManager &getSourceManager() const { return SourceMgr; }
-  MemoryBufferCache &getPCMCache() const { return PCMCache; }
   HeaderSearch &getHeaderSearchInfo() const { return HeaderInfo; }
 
   IdentifierTable &getIdentifierTable() { return Identifiers; }

clang/include/clang/Serialization/ASTReader.h

@@ -97,7 +97,7 @@ class HeaderSearchOptions;
 class LangOptions;
 class LazyASTUnresolvedSet;
 class MacroInfo;
-class MemoryBufferCache;
+class InMemoryModuleCache;
 class NamedDecl;
 class NamespaceDecl;
 class ObjCCategoryDecl;
@@ -440,9 +440,6 @@ class ASTReader
   /// The module manager which manages modules and their dependencies
   ModuleManager ModuleMgr;
 
-  /// The cache that manages memory buffers for PCM files.
-  MemoryBufferCache &PCMCache;
-
   /// A dummy identifier resolver used to merge TU-scope declarations in
   /// C, for the cases where we don't have a Sema object to provide a real
   /// identifier resolver.
@@ -1481,8 +1478,8 @@ class ASTReader
   ///
   /// \param ReadTimer If non-null, a timer used to track the time spent
   /// deserializing.
-  ASTReader(Preprocessor &PP, ASTContext *Context,
-            const PCHContainerReader &PCHContainerRdr,
+  ASTReader(Preprocessor &PP, InMemoryModuleCache &ModuleCache,
+            ASTContext *Context, const PCHContainerReader &PCHContainerRdr,
             ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
             StringRef isysroot = "", bool DisableValidation = false,
             bool AllowASTWithCompilerErrors = false,

clang/include/clang/Serialization/ASTWriter.h

@@ -74,8 +74,8 @@ class IdentifierResolver;
 class LangOptions;
 class MacroDefinitionRecord;
 class MacroInfo;
-class MemoryBufferCache;
 class Module;
+class InMemoryModuleCache;
 class ModuleFileExtension;
 class ModuleFileExtensionWriter;
 class NamedDecl;
@@ -132,7 +132,7 @@ class ASTWriter : public ASTDeserializationListener,
   const SmallVectorImpl<char> &Buffer;
 
   /// The PCM manager which manages memory buffers for pcm files.
-  MemoryBufferCache &PCMCache;
+  InMemoryModuleCache &ModuleCache;
 
   /// The ASTContext we're writing.
   ASTContext *Context = nullptr;
@@ -542,7 +542,7 @@ class ASTWriter : public ASTDeserializationListener,
   /// Create a new precompiled header writer that outputs to
   /// the given bitstream.
   ASTWriter(llvm::BitstreamWriter &Stream, SmallVectorImpl<char> &Buffer,
-            MemoryBufferCache &PCMCache,
+            InMemoryModuleCache &ModuleCache,
             ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
             bool IncludeTimestamps = true);
   ~ASTWriter() override;
@@ -981,7 +981,8 @@ class PCHGenerator : public SemaConsumer {
   SmallVectorImpl<char> &getPCH() const { return Buffer->Data; }
 
 public:
-  PCHGenerator(const Preprocessor &PP, StringRef OutputFile, StringRef isysroot,
+  PCHGenerator(const Preprocessor &PP, InMemoryModuleCache &ModuleCache,
+               StringRef OutputFile, StringRef isysroot,
                std::shared_ptr<PCHBuffer> Buffer,
                ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
                bool AllowASTWithErrors = false, bool IncludeTimestamps = true);

clang/include/clang/Basic/MemoryBufferCache.h renamed to clang/include/clang/Serialization/InMemoryModuleCache.h

@@ -1,15 +1,16 @@
-//===- MemoryBufferCache.h - Cache for loaded memory buffers ----*- C++ -*-===//
+//===- InMemoryModuleCache.h - In-memory cache for modules ------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_BASIC_MEMORYBUFFERCACHE_H
-#define LLVM_CLANG_BASIC_MEMORYBUFFERCACHE_H
+#ifndef LLVM_CLANG_SERIALIZATION_INMEMORYMODULECACHE_H
+#define LLVM_CLANG_SERIALIZATION_INMEMORYMODULECACHE_H
 
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringMap.h"
 #include <memory>
 
@@ -19,25 +20,30 @@ class MemoryBuffer;
 
 namespace clang {
 
-/// Manage memory buffers across multiple users.
+/// In-memory cache for modules.
 ///
-/// Ensures that multiple users have a consistent view of each buffer.  This is
-/// used by \a CompilerInstance when building PCMs to ensure that each \a
-/// ModuleManager sees the same files.
+/// This is a cache for modules for use across a compilation, sharing state
+/// between the CompilerInstances in an implicit modules build.  It must be
+/// shared by each CompilerInstance, ASTReader, ASTWriter, and ModuleManager
+/// that are coordinating.
+///
+/// Critically, it ensures that a single process has a consistent view of each
+/// PCM.  This is used by \a CompilerInstance when building PCMs to ensure that
+/// each \a ModuleManager sees the same files.
 ///
 /// \a finalizeCurrentBuffers() should be called before creating a new user.
-/// This locks in the current buffers, ensuring that no buffer that has already
-/// been accessed can be purged, preventing use-after-frees.
-class MemoryBufferCache : public llvm::RefCountedBase<MemoryBufferCache> {
-  struct BufferEntry {
+/// This locks in the current PCMs, ensuring that no PCM that has already been
+/// accessed can be purged, preventing use-after-frees.
+class InMemoryModuleCache : public llvm::RefCountedBase<InMemoryModuleCache> {
+  struct PCM {
     std::unique_ptr<llvm::MemoryBuffer> Buffer;
 
     /// Track the timeline of when this was added to the cache.
     unsigned Index;
   };
 
   /// Cache of buffers.
-  llvm::StringMap<BufferEntry> Buffers;
+  llvm::StringMap<PCM> PCMs;
 
   /// Monotonically increasing index.
   unsigned NextIndex = 0;
@@ -76,4 +82,4 @@ class MemoryBufferCache : public llvm::RefCountedBase<MemoryBufferCache> {
 
 } // end namespace clang
 
-#endif // LLVM_CLANG_BASIC_MEMORYBUFFERCACHE_H
+#endif // LLVM_CLANG_SERIALIZATION_INMEMORYMODULECACHE_H

clang/include/clang/Serialization/Module.h

@@ -174,7 +174,7 @@ class ModuleFile {
   unsigned Generation;
 
   /// The memory buffer that stores the data associated with
-  /// this AST file, owned by the PCMCache in the ModuleManager.
+  /// this AST file, owned by the InMemoryModuleCache.
   llvm::MemoryBuffer *Buffer;
 
   /// The size of this file, in bits.

clang/include/clang/Serialization/ModuleManager.h

@@ -38,7 +38,7 @@ class FileEntry;
 class FileManager;
 class GlobalModuleIndex;
 class HeaderSearch;
-class MemoryBufferCache;
+class InMemoryModuleCache;
 class ModuleMap;
 class PCHContainerReader;
 
@@ -67,7 +67,7 @@ class ModuleManager {
   FileManager &FileMgr;
 
   /// Cache of PCM files.
-  IntrusiveRefCntPtr<MemoryBufferCache> PCMCache;
+  IntrusiveRefCntPtr<InMemoryModuleCache> ModuleCache;
 
   /// Knows how to unwrap module containers.
   const PCHContainerReader &PCHContainerRdr;
@@ -139,7 +139,7 @@ class ModuleManager {
       SmallVectorImpl<std::unique_ptr<ModuleFile>>::reverse_iterator>;
   using ModuleOffset = std::pair<uint32_t, StringRef>;
 
-  explicit ModuleManager(FileManager &FileMgr, MemoryBufferCache &PCMCache,
+  explicit ModuleManager(FileManager &FileMgr, InMemoryModuleCache &ModuleCache,
                          const PCHContainerReader &PCHContainerRdr,
                          const HeaderSearch &HeaderSearchInfo);
   ~ModuleManager();
@@ -317,7 +317,7 @@ class ModuleManager {
   /// View the graphviz representation of the module graph.
   void viewGraph();
 
-  MemoryBufferCache &getPCMCache() const { return *PCMCache; }
+  InMemoryModuleCache &getModuleCache() const { return *ModuleCache; }
 };
 
 } // namespace serialization

clang/lib/Basic/CMakeLists.txt

@@ -50,7 +50,6 @@ add_clang_library(clangBasic
   FixedPoint.cpp
   IdentifierTable.cpp
   LangOptions.cpp
-  MemoryBufferCache.cpp
   Module.cpp
   ObjCRuntime.cpp
   OpenMPKinds.cpp