Integrated: 8308031: Linkers should reject unpromoted variadic parameters

[Jorn Vernee]

On Tue, 30 May 2023 17:25:35 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> In C, arguments smaller than `int` are promoted to (`unsigned`) `int`, and `float` is promoted to `double`, when being passed as variadic argument (see e.g. https://en.cppreference.com/w/c/language/conversion#Default_argument_promotions). This patch adds the automatic argument promotion for variadic arguments, to align the implementation with the C specification.
> 
> The fallback linker is also updated to use to correct function to link variadic calls (not doing this turned out not to be a problem so far, but it is problematic for instance on Mac/AArch64 when using the fallback linker). Adding the restriction on layouts for all linkers is also partly motivated by the fallback linker rejecting such unsupported variadic layouts already.
> 
> I've added a small paragraph to the Linker javadoc as well that explains this.
> 
> TestVarArgs needed to be updated in order to account for the difference in the promoted `float` values.
> 
> Testing:
> - local testing on Windows/x64
> - local testing on Linux/x64 using the fallback linker
> - tier1-3 + jdk-tier5
> - manual test run on mac/aarch64 with the fallback linker to verify the correctness of the fallback linker changes.

This pull request has now been integrated.

Changeset: fa791119
Author:    Jorn Vernee <jvernee at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/fa791119f0b73cd1e110d6a62d3bed58fee5740a
Stats:     144 lines in 11 files changed: 120 ins; 6 del; 18 mod

8308031: Linkers should reject unpromoted variadic parameters

Reviewed-by: mcimadamore

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PR: https://git.openjdk.org/jdk/pull/14225