org.jikesrvm.jni.ia32

Class JNIGCMapIterator

java.lang.Object

org.jikesrvm.mm.mminterface.GCMapIterator

org.jikesrvm.jni.ia32.JNIGCMapIterator

public final class JNIGCMapIterator
extends GCMapIterator

Iterator for stack frames inserted at the transition from Java to JNI Native C. It will report JREFs associated with the executing C frames which are in the "JREFs stack" attached to the executing Threads JNIEnvironment. It will update register location addresses for the non-volatile registers to point to the registers saved in the transition frame.

See Also:

JNICompiler

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	jniFramePtr
(package private) int	jniNextRef
(package private) AddressArray	jniRefs

Fields inherited from class org.jikesrvm.mm.mminterface.GCMapIterator

framePtr, registerLocations, thread

Constructor Summary

Constructors

Constructor and Description
JNIGCMapIterator(AddressArray registerLocations)

Method Summary

Modifier and Type	Method and Description
void	cleanupPointers() Iteration is complete, release any internal data structures including locks acquired during setupIterator for jsr maps.
Address	getNextReferenceAddress() Get address of next object reference held by current stackframe.
Address	getNextReturnAddressAddress() Get address of next JSR return address held by current stackframe.
int	getType() Get the type of this iterator (BASELINE, OPT, etc.).
void	newStackWalk(RVMThread thread) Prepare to scan a thread's stack and saved registers for object references.
void	reset() Prepare to re-iterate on same stackframe, and to switch between "reference" iteration and "JSR return address" iteration.
void	setupIterator(CompiledMethod compiledMethod, Offset instructionOffset, Address framePtr) Prepare to iterate over object references and JSR return addresses held by a stackframe.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

jniRefs

AddressArray jniRefs

jniNextRef

int jniNextRef

jniFramePtr

int jniFramePtr

Constructor Detail

JNIGCMapIterator

public JNIGCMapIterator(AddressArray registerLocations)

Method Detail

newStackWalk

public void newStackWalk(RVMThread thread)

Description copied from class: GCMapIterator

Prepare to scan a thread's stack and saved registers for object references.

Overrides:

newStackWalk in class GCMapIterator

Parameters:

thread - Thread whose stack is being scanned

setupIterator

public void setupIterator(CompiledMethod compiledMethod,
                          Offset instructionOffset,
                          Address framePtr)

Description copied from class: GCMapIterator

Prepare to iterate over object references and JSR return addresses held by a stackframe.

Specified by:

setupIterator in class GCMapIterator

Parameters:

compiledMethod - method running in the stackframe

instructionOffset - offset of current instruction within that method's code

framePtr - address of stackframe to be visited

getNextReferenceAddress

public Address getNextReferenceAddress()

Description copied from class: GCMapIterator

Get address of next object reference held by current stackframe. Returns zero when there are no more references to report.

Side effect: registerLocations[] updated at end of iteration. TODO: registerLocations[] update should be done via separately called method instead of as side effect.

Specified by:

getNextReferenceAddress in class GCMapIterator

Returns:

address of word containing an object reference zero if no more references to report

getNextReturnAddressAddress

public Address getNextReturnAddressAddress()

Description copied from class: GCMapIterator

Get address of next JSR return address held by current stackframe.

Specified by:

getNextReturnAddressAddress in class GCMapIterator

Returns:

address of word containing a JSR return address zero if no more return addresses to report

reset

public void reset()

Description copied from class: GCMapIterator

Prepare to re-iterate on same stackframe, and to switch between "reference" iteration and "JSR return address" iteration.

Specified by:

reset in class GCMapIterator

cleanupPointers

public void cleanupPointers()

Description copied from class: GCMapIterator

Iteration is complete, release any internal data structures including locks acquired during setupIterator for jsr maps.

Specified by:

cleanupPointers in class GCMapIterator

getType

public int getType()

Description copied from class: GCMapIterator

Get the type of this iterator (BASELINE, OPT, etc.). Called from GCMapIteratorGroup to select which iterator to use for a stackframe. The possible types are specified in CompiledMethod.

Specified by:

getType in class GCMapIterator

Returns:

type code for this iterator