#include <SectionMemoryManager.h>

Data Structures
struct	FreeMemBlock

struct	MemoryGroup

class	MemoryMapper

Public Types
enum class	AllocationPurpose { Code , ROData , RWData }

Public Member Functions
	SectionMemoryManager (MemoryMapper *MM=nullptr, bool ReserveAlloc=false)

	SectionMemoryManager (const SectionMemoryManager &)=delete

void	operator= (const SectionMemoryManager &)=delete

	~SectionMemoryManager () override

bool	needsToReserveAllocationSpace () override
	Enable reserveAllocationSpace when requested. More...

virtual void	reserveAllocationSpace (uintptr_t CodeSize, uint32_t CodeAlign, uintptr_t RODataSize, uint32_t RODataAlign, uintptr_t RWDataSize, uint32_t RWDataAlign) override

uint8_t *	allocateCodeSection (uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName) override

uint8_t *	allocateDataSection (uintptr_t Size, unsigned Alignment, unsigned SectionID, StringRef SectionName, bool IsReadOnly) override

bool	finalizeMemory (std::string *ErrMsg=nullptr) override

virtual void	invalidateInstructionCache ()

Private Member Functions
uint8_t *	allocateSection (AllocationPurpose Purpose, uintptr_t Size, unsigned Alignment)

std::error_code	applyMemoryGroupPermissions (MemoryGroup &MemGroup, unsigned Permissions)

bool	hasSpace (const MemoryGroup &MemGroup, uintptr_t Size) const

void	anchor () override

Private Attributes
MemoryGroup	CodeMem

MemoryGroup	RWDataMem

MemoryGroup	RODataMem

MemoryMapper *	MMapper

std::unique_ptr< MemoryMapper >	OwnedMMapper

bool	ReserveAllocation

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 46 of file SectionMemoryManager.h.

Member Enumeration Documentation

◆ AllocationPurpose

enum class llvm::backport::SectionMemoryManager::AllocationPurpose

strong

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

Enumerator
Code
ROData
RWData

Definition at line 50 of file SectionMemoryManager.h.

                               {
    Code,
    ROData,
    RWData,
  };

Constructor & Destructor Documentation

◆ SectionMemoryManager() [1/2]

llvm::backport::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.

◆ SectionMemoryManager() [2/2]

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

delete

◆ ~SectionMemoryManager()

llvm::backport::SectionMemoryManager::~SectionMemoryManager ( )

override

Member Function Documentation

◆ allocateCodeSection()

uint8_t * llvm::backport::SectionMemoryManager::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.

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

◆ allocateDataSection()

uint8_t * llvm::backport::SectionMemoryManager::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.

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

◆ allocateSection()

uint8_t * llvm::backport::SectionMemoryManager::allocateSection	(	AllocationPurpose	Purpose,
		uintptr_t	Size,
		unsigned	Alignment
	)

private

◆ anchor()

void llvm::backport::SectionMemoryManager::anchor ( )

overrideprivate

◆ applyMemoryGroupPermissions()

std::error_code llvm::backport::SectionMemoryManager::applyMemoryGroupPermissions	(	MemoryGroup &	MemGroup,
		unsigned	Permissions
	)

private

◆ finalizeMemory()

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

override

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.

◆ hasSpace()

bool llvm::backport::SectionMemoryManager::hasSpace	(	const MemoryGroup &	MemGroup,
		uintptr_t	Size
	)		const

private

◆ invalidateInstructionCache()

virtual void llvm::backport::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.

◆ needsToReserveAllocationSpace()

bool llvm::backport::SectionMemoryManager::needsToReserveAllocationSpace ( )

inlineoverride

Enable reserveAllocationSpace when requested.

Definition at line 123 of file SectionMemoryManager.h.

123{ return ReserveAllocation; }

llvm::backport::SectionMemoryManager::ReserveAllocation

bool ReserveAllocation

Definition: SectionMemoryManager.h:220

References ReserveAllocation.

◆ operator=()

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

delete

◆ reserveAllocationSpace()

virtual void llvm::backport::SectionMemoryManager::reserveAllocationSpace	(	uintptr_t	CodeSize,
		uint32_t	CodeAlign,
		uintptr_t	RODataSize,
		uint32_t	RODataAlign,
		uintptr_t	RWDataSize,
		uint32_t	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.

Field Documentation

◆ CodeMem

MemoryGroup llvm::backport::SectionMemoryManager::CodeMem

private

Definition at line 215 of file SectionMemoryManager.h.

◆ MMapper

MemoryMapper* llvm::backport::SectionMemoryManager::MMapper

private

Definition at line 218 of file SectionMemoryManager.h.

◆ OwnedMMapper

std::unique_ptr<MemoryMapper> llvm::backport::SectionMemoryManager::OwnedMMapper

private

Definition at line 219 of file SectionMemoryManager.h.

◆ ReserveAllocation

bool llvm::backport::SectionMemoryManager::ReserveAllocation

private

Definition at line 220 of file SectionMemoryManager.h.

Referenced by needsToReserveAllocationSpace().

◆ RODataMem

MemoryGroup llvm::backport::SectionMemoryManager::RODataMem

private

Definition at line 217 of file SectionMemoryManager.h.

◆ RWDataMem

MemoryGroup llvm::backport::SectionMemoryManager::RWDataMem

private

Definition at line 216 of file SectionMemoryManager.h.

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

src/include/jit/SectionMemoryManager.h

Data Structures

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ AllocationPurpose

Constructor & Destructor Documentation

◆ SectionMemoryManager() [1/2]

◆ SectionMemoryManager() [2/2]

◆ ~SectionMemoryManager()

Member Function Documentation

◆ allocateCodeSection()

◆ allocateDataSection()

◆ allocateSection()

◆ anchor()

◆ applyMemoryGroupPermissions()

◆ finalizeMemory()

◆ hasSpace()

◆ invalidateInstructionCache()

◆ needsToReserveAllocationSpace()

◆ operator=()

◆ reserveAllocationSpace()

Field Documentation

◆ CodeMem

◆ MMapper

◆ OwnedMMapper

◆ ReserveAllocation

◆ RODataMem

◆ RWDataMem