llvm::JITMemoryManager Class Reference

#include <JITMemoryManager.h>

Collaboration diagram for llvm::JITMemoryManager:

[legend]

List of all members.

Public Member Functions
	JITMemoryManager ()
virtual	~JITMemoryManager ()
virtual void	setMemoryWritable (void)=0
virtual void	setMemoryExecutable (void)=0
virtual void	AllocateGOT ()=0
bool	isManagingGOT () const
virtual unsigned char *	getGOTBase () const =0
bool	NeedsExactSize () const
virtual unsigned char *	startFunctionBody (const Function *F, uintptr_t &ActualSize)=0
virtual unsigned char *	allocateStub (const GlobalValue *F, unsigned StubSize, unsigned Alignment)=0
virtual void	endFunctionBody (const Function *F, unsigned char *FunctionStart, unsigned char *FunctionEnd)=0
virtual unsigned char *	allocateSpace (intptr_t Size, unsigned Alignment)=0
	allocateSpace - Allocate a memory block of the given size.
virtual void	deallocateMemForFunction (const Function *F)=0
virtual unsigned char *	startExceptionTable (const Function *F, uintptr_t &ActualSize)=0
virtual void	endExceptionTable (const Function *F, unsigned char *TableStart, unsigned char *TableEnd, unsigned char *FrameRegister)=0
Static Public Member Functions
static JITMemoryManager *	CreateDefaultMemManager ()
Protected Attributes
bool	HasGOT
bool	SizeRequired

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Detailed Description

JITMemoryManager - This interface is used by the JIT to allocate and manage memory for the code generated by the JIT. This can be reimplemented by clients that have a strong desire to control how the layout of JIT'd memory works.

Definition at line 26 of file JITMemoryManager.h.

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Constructor & Destructor Documentation

llvm::JITMemoryManager::JITMemoryManager

(

)

[inline]

Definition at line 31 of file JITMemoryManager.h.

JITMemoryManager::~JITMemoryManager

(

)

[virtual]

Definition at line 27 of file JITMemoryManager.cpp.

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Member Function Documentation

JITMemoryManager * JITMemoryManager::CreateDefaultMemManager

(

)

[static]

CreateDefaultMemManager - This is used to create the default JIT Memory Manager if the client does not provide one to the JIT.

Definition at line 513 of file JITMemoryManager.cpp.

virtual void llvm::JITMemoryManager::setMemoryWritable

(

void

)

[pure virtual]

setMemoryWritable - When code generation is in progress, the code pages may need permissions changed.

virtual void llvm::JITMemoryManager::setMemoryExecutable

(

void

)

[pure virtual]

setMemoryExecutable - When code generation is done and we're ready to start execution, the code pages may need permissions changed.

virtual void llvm::JITMemoryManager::AllocateGOT

(

)

[pure virtual]

AllocateGOT - If the current table requires a Global Offset Table, this method is invoked to allocate it. This method is required to set HasGOT to true.

bool llvm::JITMemoryManager::isManagingGOT

(

)

const [inline]

isManagingGOT - Return true if the AllocateGOT method is called.

Definition at line 57 of file JITMemoryManager.h.

References HasGOT.

virtual unsigned char* llvm::JITMemoryManager::getGOTBase

(

)

const [pure virtual]

getGOTBase - If this is managing a Global Offset Table, this method should return a pointer to its base.

bool llvm::JITMemoryManager::NeedsExactSize

(

)

const [inline]

NeedsExactSize - If the memory manager requires to know the size of the objects to be emitted

Definition at line 67 of file JITMemoryManager.h.

References SizeRequired.

virtual unsigned char* llvm::JITMemoryManager::startFunctionBody	(	const Function *	F,
		uintptr_t &	ActualSize
	)			[pure virtual]

startFunctionBody - When we start JITing a function, the JIT calls this method to allocate a block of free RWX memory, which returns a pointer to it. The JIT doesn't know ahead of time how much space it will need to emit the function, so it doesn't pass in the size. Instead, this method is required to pass back a "valid size". The JIT will be careful to not write more than the returned ActualSize bytes of memory.

virtual unsigned char* llvm::JITMemoryManager::allocateStub	(	const GlobalValue *	F,
		unsigned	StubSize,
		unsigned	Alignment
	)			[pure virtual]

allocateStub - This method is called by the JIT to allocate space for a function stub (used to handle limited branch displacements) while it is JIT compiling a function. For example, if foo calls bar, and if bar either needs to be lazily compiled or is a native function that exists too far away from the call site to work, this method will be used to make a thunk for it. The stub should be "close" to the current function body, but should not be included in the 'actualsize' returned by startFunctionBody.

virtual void llvm::JITMemoryManager::endFunctionBody	(	const Function *	F,
		unsigned char *	FunctionStart,
		unsigned char *	FunctionEnd
	)			[pure virtual]

endFunctionBody - This method is called when the JIT is done codegen'ing the specified function. At this point we know the size of the JIT compiled function. This passes in FunctionStart (which was returned by the startFunctionBody method) and FunctionEnd which is a pointer to the actual end of the function. This method should mark the space allocated and remember where it is in case the client wants to deallocate it.

virtual unsigned char* llvm::JITMemoryManager::allocateSpace	(	intptr_t	Size,
		unsigned	Alignment
	)			[pure virtual]

allocateSpace - Allocate a memory block of the given size.

virtual void llvm::JITMemoryManager::deallocateMemForFunction

(

const Function *

F

)

[pure virtual]

deallocateMemForFunction - Free JIT memory for the specified function. This is never called when the JIT is currently emitting a function.

virtual unsigned char* llvm::JITMemoryManager::startExceptionTable	(	const Function *	F,
		uintptr_t &	ActualSize
	)			[pure virtual]

startExceptionTable - When we finished JITing the function, if exception handling is set, we emit the exception table.

virtual void llvm::JITMemoryManager::endExceptionTable	(	const Function *	F,
		unsigned char *	TableStart,
		unsigned char *	TableEnd,
		unsigned char *	FrameRegister
	)			[pure virtual]

endExceptionTable - This method is called when the JIT is done emitting the exception table.

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Member Data Documentation

bool llvm::JITMemoryManager::HasGOT [protected]

Definition at line 28 of file JITMemoryManager.h.

Referenced by isManagingGOT().

bool llvm::JITMemoryManager::SizeRequired [protected]

Definition at line 29 of file JITMemoryManager.h.

Referenced by NeedsExactSize().

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

• JITMemoryManager.h
• JITMemoryManager.cpp