com.oracle.svm.core.os

Interface ImageHeapProvider

All Known Implementing Classes:

AbstractCopyingImageHeapProvider, AbstractImageHeapProvider, CopyingImageHeapProvider, DarwinImageHeapProvider, LinuxImageHeapProvider, WindowsImageHeapProvider

public interface ImageHeapProvider

Provides new instances of the image heap for creating isolates. The same image heap provider implementation can be shared by different garbage collectors.

When a heap base is used, then the image heap is always mapped in a way that the memory at the heap base is protected and marked as inaccessible. Depending on the specific scenario, that memory may or may not be part of the Native Image file (see Heap.getImageHeapNullRegionSize() and Heap.getImageHeapOffsetInAddressSpace() for more details). This is done regardless of the used GC, platform, or CPU architecture:

 | protected memory | image heap |
 ^
 heapBase
 

Method Summary

Modifier and Type	Method and Description
int	freeImageHeap(org.graalvm.word.PointerBase heapBase) Disposes an instance of the image heap that was created with this provider.
static ImageHeapProvider	get()
boolean	guaranteesHeapPreferredAddressSpaceAlignment() Returns whether this provider, when not already supplied a reserved address space by CommittedMemoryProvider, will always ensure a heap address space alignment of Heap.getPreferredAddressSpaceAlignment() at image runtime.
int	initialize(org.graalvm.word.Pointer reservedAddressSpace, org.graalvm.word.UnsignedWord reservedSize, org.graalvm.nativeimage.c.type.WordPointer basePointer, org.graalvm.nativeimage.c.type.WordPointer endPointer) Creates a new instance of the image heap.

Method Detail

get

static ImageHeapProvider get()

guaranteesHeapPreferredAddressSpaceAlignment

boolean guaranteesHeapPreferredAddressSpaceAlignment()

Returns whether this provider, when not already supplied a reserved address space by CommittedMemoryProvider, will always ensure a heap address space alignment of Heap.getPreferredAddressSpaceAlignment() at image runtime.

initialize

int initialize(org.graalvm.word.Pointer reservedAddressSpace,
               org.graalvm.word.UnsignedWord reservedSize,
               org.graalvm.nativeimage.c.type.WordPointer basePointer,
               org.graalvm.nativeimage.c.type.WordPointer endPointer)

Creates a new instance of the image heap.

Parameters:

reservedAddressSpace - If non-null, this specifies the address of a contiguous block of memory in which the image heap and the Java heap should be placed. If null, the ImageHeapProvider is responsible for allocating sufficient memory for the image heap at an arbitrary address.

reservedSize - If reservedAddressSpace is non-null, the number of reserved bytes at that address.

basePointer - An address where a pointer to the start address of the image heap instance will be written. Must not be null.

endPointer - An address where a pointer to the end of the image heap instance will be written. May be null if this value is not required.

Returns:

a result code from CEntryPointErrors.

freeImageHeap

int freeImageHeap(org.graalvm.word.PointerBase heapBase)

Disposes an instance of the image heap that was created with this provider. This method must only be called if the image heap memory was allocated by the ImageHeapProvider.