> When a virtual thread suspended at a breakpoint gets unmounted and mounted > again only the top frame is thawed. The caller stays frozen in the stack > chunk and the popped frame returns into the continuation return barrier. The > interpreter's popframe entry treats that return address like a deoptimized > caller, preserves the arguments, sets the reexecution bit and returns. The > barrier then thawed the caller as a plain return. Arguments and bit left > behind, no reexecution of the invoke, run() went on with a zero result. > > Thaw finishes it now. An interpreted caller gets the preserved arguments back > on its expression stack and its return slot is patched to the interpreter > deopt entry after push_return_frame, the x86 deopt entry reloads rsp from > last_sp for that, aarch64 already does. A compiled caller frozen in the chunk > is deoptimized from UpdateForPopTopFrameClosure::doit the same way > set_frame_pop does it. Thaw leaves the arguments alone in that case and > unpack_on_stack puts them back. A frozen compiled frame being popped stays > opaque. > > A linkTo caller needs one more thing. The linker consumed the trailing > MemberName before the target ran and the preserved arguments are sized by the > target, so the MemberName is not among them. Thaw takes it from the caller's > local 0 the way the interpreter's popframe entry does, the lookup from > member_name_arg_or_null moved into a plain helper both can call. The > arguments go one slot up and the MemberName goes back on top. > > popframes002 runs popframes001 on a virtual thread with the join Chris > Plummer wrote enabled by a property in the debuggee. It unmounts the tested > thread before the breakpoint so the caller is frozen when popped, and run() > is excluded from compilation so this stays the interpreted case. popframes003 > is the compiled caller case, -Xcomp with the breakpoint in a separate stop() > so testedMethod keeps its compiled frame and run() stays frozen, the debugger > pops frame 1 and the debuggee checks with WhiteBox that run() and > testedMethod are compiled and that testedMethod ran twice. > -XX:+PreserveFramePointer keeps the thaw on the slow path. Both fail on > master without the hotspot change. popframes001 itself runs the plain case as > before and is off the virtual problem list. If separate copies of the > debugger and debuggee are preferred over the properties that is easy to > change. PopFrameMethodNameInvariantTest got an unmount mode, the same > linkToStatic pop on a virtual thread that sleeps before the breakpoint so its ca...
Shiv Shah has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 21 additional commits since the last revision: - Merge remote-tracking branch 'upstream/master' into JDK-8391440 - Require continuations for the frozen caller runs and add popframes002 to the jdwp quick group - Keep testedMethod and run free of deoptimization before the freeze, drop the WhiteBox check - Break in stop() and pop its caller in popframes003, make the unmount deterministic - Put the MemberName back for a linkTo caller and factor the popframe block out - Run popframes002 and popframes003 on the popframes001 classes - Patch the return pc instead of rebuilding the frame - Exclude the popframes002 caller from compilation - Keep the popframes002 caller interpreted and add popframes003 for a compiled one - Deoptimize a frozen compiled caller instead of refusing the pop - ... and 11 more: https://git.openjdk.org/jdk/compare/c803e827...3d4ad029 ------------- Changes: - all: https://git.openjdk.org/jdk/pull/32661/files - new: https://git.openjdk.org/jdk/pull/32661/files/173a40d5..3d4ad029 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=32661&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=32661&range=00-01 Stats: 84312 lines in 1865 files changed: 50995 ins; 23483 del; 9834 mod Patch: https://git.openjdk.org/jdk/pull/32661.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/32661/head:pull/32661 PR: https://git.openjdk.org/jdk/pull/32661
