In-memory cache for modules. More...

#include "clang/Serialization/InMemoryModuleCache.h"

Inheritance diagram for clang::InMemoryModuleCache:

Public Types
enum	State { Unknown , Tentative , ToBuild , Final }
	There are four states for a PCM. More...

Public Member Functions
	InMemoryModuleCache (AtomicLineLogger &Logger)
State	getPCMState (llvm::StringRef Filename) const
	Get the state of the PCM.
llvm::MemoryBuffer &	addPCM (llvm::StringRef Filename, std::unique_ptr< llvm::MemoryBuffer > Buffer, off_t Size, time_t ModTime)
	Store the PCM under the Filename.
llvm::MemoryBuffer &	addBuiltPCM (llvm::StringRef Filename, std::unique_ptr< llvm::MemoryBuffer > Buffer, off_t Size, time_t ModTime)
	Store a just-built PCM under the Filename.
bool	tryToDropPCM (llvm::StringRef Filename)
	Try to remove a buffer from the cache.
void	finalizePCM (llvm::StringRef Filename)
	Mark a PCM as final.
llvm::MemoryBuffer *	lookupPCM (llvm::StringRef Filename, off_t &Size, time_t &ModTime) const
	Get a pointer to the PCM if it exists and set `Size` and `ModTime` to its on-disk size and modification time.
bool	isPCMFinal (llvm::StringRef Filename) const
	Check whether the PCM is final and has been shown to work.
bool	shouldBuildPCM (llvm::StringRef Filename) const
	Check whether the PCM is waiting to be built.

Detailed Description

In-memory cache for modules.

This is a cache for modules for use across a compilation, sharing state between the CompilerInstances in a 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 implicitly-built PCM. This is used by CompilerInstance when building PCMs to ensure that each ModuleManager sees the same files.

Definition at line 30 of file InMemoryModuleCache.h.

Member Enumeration Documentation

◆ State

enum clang::InMemoryModuleCache::State

There are four states for a PCM.

It must monotonically increase.

Unknown: the PCM has neither been read from disk nor built.
Tentative: the PCM has been read from disk but not yet imported or built. It might work.
ToBuild: the PCM read from disk did not work but a new one has not been built yet.
Final: indicating that the current PCM was either built in this process or has been successfully imported.

Enumerator
Unknown
Tentative
ToBuild
Final

Definition at line 69 of file InMemoryModuleCache.h.

Constructor & Destructor Documentation

◆ InMemoryModuleCache()

clang::InMemoryModuleCache::InMemoryModuleCache ( AtomicLineLogger & Logger )

inlineexplicit

Definition at line 58 of file InMemoryModuleCache.h.

Member Function Documentation

◆ addBuiltPCM()

llvm::MemoryBuffer & InMemoryModuleCache::addBuiltPCM	(	llvm::StringRef	Filename,
		std::unique_ptr< llvm::MemoryBuffer >	Buffer,
		off_t	Size,
		time_t	ModTime )

Store a just-built PCM under the Filename.

Precondition: state is Unknown or ToBuild.; state is not Tentative.

Returns: a reference to the buffer as a convenience.

Definition at line 37 of file InMemoryModuleCache.cpp.

Referenced by compileModuleImpl(), and createASTReader().

◆ addPCM()

llvm::MemoryBuffer & InMemoryModuleCache::addPCM	(	llvm::StringRef	Filename,
		std::unique_ptr< llvm::MemoryBuffer >	Buffer,
		off_t	Size,
		time_t	ModTime )

Store the PCM under the Filename.

Precondition: state is Unknown

Postcondition: state is Tentative

Returns: a reference to the buffer as a convenience.

Definition at line 26 of file InMemoryModuleCache.cpp.

Referenced by clang::serialization::ModuleManager::addModule().

◆ finalizePCM()

void InMemoryModuleCache::finalizePCM ( llvm::StringRef Filename )

Mark a PCM as final.

Precondition: state is Tentative or Final.

Postcondition: state is Final.

Definition at line 88 of file InMemoryModuleCache.cpp.

◆ getPCMState()

InMemoryModuleCache::State InMemoryModuleCache::getPCMState ( llvm::StringRef Filename ) const

Get the state of the PCM.

Definition at line 16 of file InMemoryModuleCache.cpp.

References Final, Tentative, ToBuild, and Unknown.

Referenced by isPCMFinal(), and shouldBuildPCM().

◆ isPCMFinal()

bool InMemoryModuleCache::isPCMFinal ( llvm::StringRef Filename ) const

Check whether the PCM is final and has been shown to work.

Returns: true iff state is Final.

Definition at line 63 of file InMemoryModuleCache.cpp.

References Final, and getPCMState().

◆ lookupPCM()

llvm::MemoryBuffer * InMemoryModuleCache::lookupPCM	(	llvm::StringRef	Filename,
		off_t &	Size,
		time_t &	ModTime ) const

Get a pointer to the PCM if it exists and set Size and ModTime to its on-disk size and modification time.

Otherwise, return nullptr and don't change Size and ModTime.

Definition at line 51 of file InMemoryModuleCache.cpp.

Referenced by clang::ASTReader::readASTFileControlBlock().

◆ shouldBuildPCM()

bool InMemoryModuleCache::shouldBuildPCM ( llvm::StringRef Filename ) const

Check whether the PCM is waiting to be built.

Returns: true iff state is ToBuild.

Definition at line 67 of file InMemoryModuleCache.cpp.

References getPCMState(), and ToBuild.

◆ tryToDropPCM()

bool InMemoryModuleCache::tryToDropPCM ( llvm::StringRef Filename )

Try to remove a buffer from the cache.

No effect if state is Final.

Precondition: state is Tentative/Final.

Postcondition: Tentative => ToBuild or Final => Final.

Returns: false on success, i.e. if Tentative => ToBuild.

Definition at line 71 of file InMemoryModuleCache.cpp.

The documentation for this class was generated from the following files:

include/clang/Serialization/InMemoryModuleCache.h
lib/Serialization/InMemoryModuleCache.cpp

Public Types

Public Member Functions