This is a simple memory manager which implements the methods called by the RuntimeDyld class to allocate memory for section-based loading of objects, usually those generated by the MCJIT execution engine. More...

#include "llvm/ExecutionEngine/SectionMemoryManager.h"

Inheritance diagram for llvm::SectionMemoryManager:

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Classes
class	MemoryMapper
	Implementations of this interface are used by SectionMemoryManager to request pages from the operating system. More...

Public Types
enum class	AllocationPurpose { Code , ROData , RWData }
	This enum describes the various reasons to allocate pages from allocateMappedMemory. More...
Public Types inherited from llvm::JITSymbolResolver
using	LookupSet = std::set<StringRef>
using	LookupResult = std::map<StringRef, JITEvaluatedSymbol>
using	OnResolvedFunction = unique_function<void(Expected<LookupResult>)>

Public Member Functions
	SectionMemoryManager (MemoryMapper *MM=nullptr, bool ReserveAlloc=false)
	Creates a SectionMemoryManager instance with `MM` as the associated memory mapper.
	SectionMemoryManager (const SectionMemoryManager &)=delete
void	operator= (const SectionMemoryManager &)=delete
	~SectionMemoryManager () override
bool	needsToReserveAllocationSpace () override
	Enable reserveAllocationSpace when requested.
void	reserveAllocationSpace (uintptr_t CodeSize, Align CodeAlign, uintptr_t RODataSize, Align RODataAlign, uintptr_t RWDataSize, Align RWDataAlign) override
	Implements allocating all memory in a single block.
uint8_t *	allocateCodeSection (uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName) override
	Allocates a memory block of (at least) the given size suitable for executable code.
uint8_t *	allocateDataSection (uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName, bool isReadOnly) override
	Allocates a memory block of (at least) the given size suitable for executable code.
bool	finalizeMemory (std::string *ErrMsg=nullptr) override
	Update section-specific memory permissions and other attributes.
virtual void	invalidateInstructionCache ()
	Invalidate instruction cache for code sections.
Public Member Functions inherited from llvm::RTDyldMemoryManager
	RTDyldMemoryManager ()=default
	RTDyldMemoryManager (const RTDyldMemoryManager &)=delete
void	operator= (const RTDyldMemoryManager &)=delete
	~RTDyldMemoryManager () override
void	registerEHFrames (uint8_t *Addr, uint64_t LoadAddr, size_t Size) override
	Register the EH frames with the runtime so that c++ exceptions work.
void	deregisterEHFrames () override
virtual uint64_t	getSymbolAddress (const std::string &Name)
	Legacy symbol lookup - DEPRECATED!
JITSymbol	findSymbol (const std::string &Name) override
	This method returns a RuntimeDyld::SymbolInfo for the specified function or variable.
virtual uint64_t	getSymbolAddressInLogicalDylib (const std::string &Name)
	Legacy symbol lookup – DEPRECATED!
JITSymbol	findSymbolInLogicalDylib (const std::string &Name) override
	Default to treating all modules as separate.
virtual void *	getPointerToNamedFunction (const std::string &Name, bool AbortOnFailure=true)
	This method returns the address of the specified function.
Public Member Functions inherited from llvm::MCJITMemoryManager
virtual void	notifyObjectLoaded (ExecutionEngine *EE, const object::ObjectFile &)
	This method is called after an object has been loaded into memory but before relocations are applied to the loaded sections.
virtual void	notifyObjectLoaded (RuntimeDyld &RTDyld, const object::ObjectFile &Obj)
	This method is called after an object has been loaded into memory but before relocations are applied to the loaded sections.
Public Member Functions inherited from llvm::RuntimeDyld::MemoryManager
	MemoryManager ()=default
virtual	~MemoryManager ()=default
virtual TLSSection	allocateTLSSection (uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName)
	Allocate a memory block of (at least) the given size to be used for thread-local storage (TLS).
virtual bool	allowStubAllocation () const
	Override to return false to tell LLVM no stub space will be needed.
Public Member Functions inherited from llvm::LegacyJITSymbolResolver
void	lookup (const LookupSet &Symbols, OnResolvedFunction OnResolved) final
	Performs lookup by, for each symbol, first calling findSymbolInLogicalDylib and if that fails calling findSymbol.
Expected< LookupSet >	getResponsibilitySet (const LookupSet &Symbols) final
	Performs flags lookup by calling findSymbolInLogicalDylib and returning the flags value for that symbol.
Public Member Functions inherited from llvm::JITSymbolResolver
virtual	~JITSymbolResolver ()=default
virtual bool	allowsZeroSymbols ()
	Specify if this resolver can return valid symbols with zero value.

Additional Inherited Members
Static Public Member Functions inherited from llvm::RTDyldMemoryManager
static void	registerEHFramesInProcess (uint8_t *Addr, size_t Size)
	Register EH frames in the current process.
static void	deregisterEHFramesInProcess (uint8_t *Addr, size_t Size)
	Deregister EH frames in the current process.
static uint64_t	getSymbolAddressInProcess (const std::string &Name)
	This method returns the address of the specified function or variable in the current process.
Protected Types inherited from llvm::RTDyldMemoryManager
typedef std::vector< EHFrame >	EHFrameInfos
Protected Attributes inherited from llvm::RTDyldMemoryManager
EHFrameInfos	EHFrames

Detailed Description

This is a simple memory manager which implements the methods called by the RuntimeDyld class to allocate memory for section-based loading of objects, usually those generated by the MCJIT execution engine.

This memory manager allocates all section memory as read-write. The RuntimeDyld will copy JITed section memory into these allocated blocks and perform any necessary linking and relocations.

Any client using this memory manager MUST ensure that section-specific page permissions have been applied before attempting to execute functions in the JITed object. Permissions can be applied either by calling MCJIT::finalizeObject or by calling SectionMemoryManager::finalizeMemory directly. Clients of MCJIT should call MCJIT::finalizeObject.

Definition at line 40 of file SectionMemoryManager.h.

Member Enumeration Documentation

◆ AllocationPurpose

enum class llvm::SectionMemoryManager::AllocationPurpose

strong

This enum describes the various reasons to allocate pages from allocateMappedMemory.

Enumerator
Code
ROData
RWData

Definition at line 44 of file SectionMemoryManager.h.

Constructor & Destructor Documentation

◆ SectionMemoryManager() [1/2]

llvm::SectionMemoryManager::SectionMemoryManager	(	MemoryMapper *	MM = nullptr,
		bool	ReserveAlloc = false )

Creates a SectionMemoryManager instance with MM as the associated memory mapper.

If MM is nullptr then a default memory mapper is used that directly calls into the operating system.

If ReserveAlloc is true all memory will be pre-allocated, and any attempts to allocate beyond pre-allocated memory will fail.

Definition at line 358 of file SectionMemoryManager.cpp.

Referenced by operator=(), and SectionMemoryManager().

◆ SectionMemoryManager() [2/2]

llvm::SectionMemoryManager::SectionMemoryManager ( const SectionMemoryManager & )

delete

References SectionMemoryManager().

◆ ~SectionMemoryManager()

llvm::SectionMemoryManager::~SectionMemoryManager ( )

override

Definition at line 324 of file SectionMemoryManager.cpp.

References llvm::Block.

Member Function Documentation

◆ allocateCodeSection()

uint8_t * llvm::SectionMemoryManager::allocateCodeSection	(	uintptr_t	Size,
		unsigned	Alignment,
		unsigned	SectionID,
		StringRef	SectionName )

overridevirtual

Allocates a memory block of (at least) the given size suitable for executable code.

The value of Alignment must be a power of two. If Alignment is zero a default alignment of 16 will be used.

Implements llvm::RuntimeDyld::MemoryManager.

Definition at line 123 of file SectionMemoryManager.cpp.

References Code, and Size.

◆ allocateDataSection()

uint8_t * llvm::SectionMemoryManager::allocateDataSection	(	uintptr_t	Size,
		unsigned	Alignment,
		unsigned	SectionID,
		StringRef	SectionName,
		bool	isReadOnly )

overridevirtual

Allocates a memory block of (at least) the given size suitable for executable code.

The value of Alignment must be a power of two. If Alignment is zero a default alignment of 16 will be used.

Implements llvm::RuntimeDyld::MemoryManager.

Definition at line 111 of file SectionMemoryManager.cpp.

References ROData, RWData, and Size.

◆ finalizeMemory()

bool llvm::SectionMemoryManager::finalizeMemory ( std::string * ErrMsg = nullptr )

overridevirtual

Update section-specific memory permissions and other attributes.

This method is called when object loading is complete and section page permissions can be applied. It is up to the memory manager implementation to decide whether or not to act on this method. The memory manager will typically allocate all sections as read-write and then apply specific permissions when this method is called. Code sections cannot be executed until this function has been called. In addition, any cache coherency operations needed to reliably use the memory are also performed.

Returns: true if an error occurred, false otherwise.

Implements llvm::RuntimeDyld::MemoryManager.

Definition at line 239 of file SectionMemoryManager.cpp.

References invalidateInstructionCache(), llvm::sys::Memory::MF_EXEC, and llvm::sys::Memory::MF_READ.

◆ invalidateInstructionCache()

void llvm::SectionMemoryManager::invalidateInstructionCache ( )

virtual

Invalidate instruction cache for code sections.

Some platforms with separate data cache and instruction cache require explicit cache flush, otherwise JIT code manipulations (like resolved relocations) will get to the data cache but not to the instruction cache.

This method is called from finalizeMemory.

Definition at line 318 of file SectionMemoryManager.cpp.

References llvm::Block, and llvm::sys::Memory::InvalidateInstructionCache().

Referenced by finalizeMemory().

◆ needsToReserveAllocationSpace()

bool llvm::SectionMemoryManager::needsToReserveAllocationSpace ( )

inlineoverridevirtual

Enable reserveAllocationSpace when requested.

Reimplemented from llvm::RuntimeDyld::MemoryManager.

Definition at line 117 of file SectionMemoryManager.h.

◆ operator=()

void llvm::SectionMemoryManager::operator= ( const SectionMemoryManager & )

delete

References SectionMemoryManager().

◆ reserveAllocationSpace()

void llvm::SectionMemoryManager::reserveAllocationSpace	(	uintptr_t	CodeSize,
		Align	CodeAlign,
		uintptr_t	RODataSize,
		Align	RODataAlign,
		uintptr_t	RWDataSize,
		Align	RWDataAlign )

overridevirtual

Implements allocating all memory in a single block.

This is required to limit memory offsets to fit the ARM ABI; large memory systems may otherwise allocate separate sections too far apart.

Reimplemented from llvm::RuntimeDyld::MemoryManager.

Definition at line 29 of file SectionMemoryManager.cpp.

References llvm::alignTo(), assert(), llvm::sys::MemoryBlock::base(), CodeSize, llvm::sys::Process::getPageSizeEstimate(), llvm::isAddrAligned(), llvm::sys::Memory::MF_READ, llvm::sys::Memory::MF_WRITE, PageSize, RWData, and llvm::Align::value().

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

include/llvm/ExecutionEngine/SectionMemoryManager.h
lib/ExecutionEngine/SectionMemoryManager.cpp

Classes

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ AllocationPurpose

Constructor & Destructor Documentation

◆ SectionMemoryManager() [1/2]

◆ SectionMemoryManager() [2/2]

◆ ~SectionMemoryManager()

Member Function Documentation

◆ allocateCodeSection()

◆ allocateDataSection()

◆ finalizeMemory()

◆ invalidateInstructionCache()

◆ needsToReserveAllocationSpace()

◆ operator=()

◆ reserveAllocationSpace()