Integrated: 8362169: Pointer passed to upcall may get wrong scope

[Jorn Vernee]

On Mon, 14 Jul 2025 15:33:35 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Issue copied from the JBS issue:
> 
> When an upcall stub accepts a by-value struct, and the struct is passed by the underlying ABI as a pointer to a temporary copy on the caller's stack (for instance on Windows when the struct doesn't fit into a single register), a scope is created for the duration of the upcall, to which the memory segment for this struct is attached.
> 
> However, if such a scope is created for the upcall, any other unrelated pointer argument will _also_ be attached to the same scope. This is incorrect, as unrelated pointer arguments should be attached to the global scope. The underlying issue is that, when deciding whether a particular argument needs to be attached to the scope, we check if _any_ of the argument needs to be attached to the created scope.
> 
> This PR fixes the issue by calling `boxAddress.needsScope()` in `BindingSpecializer::emitBoxAddress`, which checks only if that particular argument needs to be attached to the upcall scope.
> 
> I've also renamed the 'global' `needsScope` method, which checks whether _any_ of the arguments need a scope, to `anyArgNeedsScope` for clarity.
> 
> Testing: `jdk_foreign` test suite on Mac/Windows/Linux x64, and Mac/Linux aarch64

This pull request has now been integrated.

Changeset: 9dc62825
Author:    Jorn Vernee <jvernee at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/9dc62825b5e7300542d22df0b87b79116f3562d3
Stats:     44 lines in 3 files changed: 39 ins; 0 del; 5 mod

8362169: Pointer passed to upcall may get wrong scope

Reviewed-by: mcimadamore

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PR: https://git.openjdk.org/jdk/pull/26295