Integrated: 8268339: Upstream: 8267989: Exceptions thrown during upcalls should be handled

[Jorn Vernee]

On Mon, 7 Jun 2021 16:38:01 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Hi,
> 
> ~This is part 2 of a two part upstreaming process of the patch mentioned in the subject line. The patch was split into 2 in order to document 2 separate specification changes that arose from a change in the implementation, with 2 separate CSRs. The first patch can be found here: https://github.com/openjdk/jdk/pull/4395~
> 
> This patch adds uniform exception handling for exceptions thrown during FLA upcalls. Currently, these exceptions are either handled similarly to the VMs `CATCH` macro, or ignored after which control returns to unsuspecting native code, until control returns to Java, which will then handle the exception. The handling depends on the invocation mode.
> 
> Both of these are bad. The former because a stack trace is not printed and instead the VM exits with a fatal error. The latter is bad because an upcall completing abruptly and returning to native code which has no idea an exception occurred is unsafe, in the sense that invariants about the state of the program that the native code depends on might no longer hold.
> 
> This patch adds uniform exception handling that replaces both of these cases (see `SharedUtils::handleUncaughtException`), which prints the exception stack trace, and then unconditionally exits the VM, which is the only safe course of action at that point.
> 
> Exceptions thrown by upcalls should instead be handled during the upcall itself, for instance by translating the exception into an error code that is then returned to the native caller, which can deal with it appropriately.
> 
> See also the original review for panama-foreign: https://github.com/openjdk/panama-foreign/pull/543
> 
> Thanks,
> Jorn
> 
> Testing: `jdk_foreign` test suite.
> 
> Thanks,
> Jorn

This pull request has now been integrated.

Changeset: ab01cb54
Author:    Jorn Vernee <jvernee at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/ab01cb547dd87f76017e9b079ab68495c38ffc90
Stats:     229 lines in 8 files changed: 224 ins; 0 del; 5 mod

8268339: Upstream: 8267989: Exceptions thrown during upcalls should be handled

Reviewed-by: psandoz, mcimadamore

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PR: https://git.openjdk.java.net/jdk/pull/4396