OpenJDK 27 · sun.jvm.hotspot.runtime.amd64.AMD64CurrentFrameGuess

Should be able to be used on all amd64 platforms we support (Linux/amd64) to implement JavaThread's "currentFrameGuess()" functionality. Input is an AMD64ThreadContext; output is SP, FP, and PC for an AMD64Frame. Instantiation of the AMD64Frame is left to the caller, since we may need to subclass AMD64Frame to support signal handler frames on Unix platforms.

Algorithm is to walk up the stack within a given range (say, 512K at most) looking for a plausible PC and SP for a Java frame, also considering those coming in from the context. If we find a PC that belongs to the VM (i.e., in generated code like the interpreter or CodeCache) then we try to find an associated EBP. We repeat this until we either find a complete frame or run out of stack to look at.

Field Summary

Modifier and Type	Field and Description
private AMD64ThreadContext	context
private static final boolean	DEBUG
private Address	fpFound
private Address	pcFound
private Address	spFound
private JavaThread	thread

Constructor Summary

Access	Constructor and Description
public	AMD64CurrentFrameGuess(AMD64ThreadContext context, JavaThread thread)

Method Summary

Modifier and Type	Method and Description
private boolean	checkLastJavaSP()
public Address	getFP()
public Address	getPC() May be null if getting values from thread-local storage; take care to call the correct AMD64Frame constructor to recover this if necessary
public Address	getSP()
public boolean	run(long regionInBytesToSearch) Returns false if not able to find a frame within a reasonable range.
private void	setValues(Address sp, Address fp, Address pc)
private boolean	validateInterpreterFrame(Address sp, Address fp, Address pc)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

context	back to summary
private AMD64ThreadContext context

DEBUG	back to summary
private static final boolean DEBUG

fpFound	back to summary
private Address fpFound

pcFound	back to summary
private Address pcFound

spFound	back to summary
private Address spFound

thread	back to summary
private JavaThread thread

Constructor Detail

AMD64CurrentFrameGuess	back to summary
public AMD64CurrentFrameGuess(AMD64ThreadContext context, JavaThread thread)

Method Detail

checkLastJavaSP	back to summary
private boolean checkLastJavaSP()

getFP	back to summary
public Address getFP()

getPC	back to summary
public Address getPC() May be null if getting values from thread-local storage; take care to call the correct AMD64Frame constructor to recover this if necessary

getSP	back to summary
public Address getSP()

run	back to summary
public boolean run(long regionInBytesToSearch) Returns false if not able to find a frame within a reasonable range.

setValues	back to summary
private void setValues(Address sp, Address fp, Address pc)