clang::InMemoryModuleCache Class Reference

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
State	getPCMState (llvm::StringRef Filename) const
	Get the state of the PCM.
llvm::MemoryBuffer &	addPCM (llvm::StringRef Filename, std::unique_ptr< llvm::MemoryBuffer > Buffer)
	Store the PCM under the Filename.
llvm::MemoryBuffer &	addBuiltPCM (llvm::StringRef Filename, std::unique_ptr< llvm::MemoryBuffer > Buffer)
	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) const
	Get a pointer to the pCM if it exists; else nullptr.
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 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 CompilerInstance when building PCMs to ensure that each ModuleManager sees the same files.

Definition at line 29 of file InMemoryModuleCache.h.

Member Enumeration Documentation

State

enum clang::InMemoryModuleCache::State

There are four states for a PCM.

It must monotonically increase.

1. Unknown: the PCM has neither been read from disk nor built.
2. Tentative: the PCM has been read from disk but not yet imported or built. It might work.
3. ToBuild: the PCM read from disk did not work but a new one has not been built yet.
4. 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 56 of file InMemoryModuleCache.h.

Member Function Documentation

addBuiltPCM()

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

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 33 of file InMemoryModuleCache.cpp.

References Filename.

Referenced by clang::ASTWriter::WriteAST().

addPCM()

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

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 25 of file InMemoryModuleCache.cpp.

References Filename.

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 73 of file InMemoryModuleCache.cpp.

References Filename.

getPCMState()

InMemoryModuleCache::State InMemoryModuleCache::getPCMState

(

llvm::StringRef

Filename

)

const

Get the state of the PCM.

Definition at line 15 of file InMemoryModuleCache.cpp.

References Filename, 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 51 of file InMemoryModuleCache.cpp.

References Filename, Final, and getPCMState().

lookupPCM()

llvm::MemoryBuffer * InMemoryModuleCache::lookupPCM

(

llvm::StringRef

Filename

)

const

Get a pointer to the pCM if it exists; else nullptr.

Definition at line 44 of file InMemoryModuleCache.cpp.

References Filename.

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 55 of file InMemoryModuleCache.cpp.

References Filename, 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 59 of file InMemoryModuleCache.cpp.

References Filename.

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

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