RFR: 8041934 com/sun/jdi/RepStep.java fails on all platforms with assert(_cur_stack_depth == count_frames()) failed: cur_stack_depth out of sync

Staffan Larsen staffan.larsen at oracle.com
Thu May 8 06:06:54 UTC 2014


This is a fix for an assert in JVMTI that verifies that JVMTI’s internal notion of the number of frames on the stack is correct.

When running in -Xcomp mode and enable single-stepping (or method_entry/exit) we will revert all frames on the stack to be run by the interpreter. Only the interpreter can send single-step and method_entry/exit. However, if one of the frames is a native wrapper, that frame will not be reverted (presumably because we don't know how to do that). This will cause us to miss a method_exit event when that native frame is popped. This in turn will mess up the logic in JVMTI that keeps track of the number of frames currently on the stack (see JvmtiThreadState::_cur_stack_depth) and will trigger the assert.

The proposed solution is to include a method_exit event in the native wrapper frame if interpreted mode has been enabled. This needs updates to SharedRuntime::generate_native_wrapper() for all platforms.

Kudos to Rickard for helping me write the code.

webrev: http://cr.openjdk.java.net/~sla/8041934/webrev.00/
bug: https://bugs.openjdk.java.net/browse/JDK-8041934

The fix has been verified by running the failing test in JPRT with -Xcomp.


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