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[3.13] gh-132026: Ensure _MIPS_SIM has defined _ABI identifiers for comparison (GH-132027)#133092

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Merged

zware merged 1 commit intopython:3.13frommiss-islington:backport-6985e2e-3.13

Apr 28, 2025

Merged

[3.13] gh-132026: Ensure _MIPS_SIM has defined _ABI identifiers for comparison (GH-132027)#133092

zware merged 1 commit intopython:3.13frommiss-islington:backport-6985e2e-3.13

Apr 28, 2025

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miss-islington commentedApr 28, 2025•
edited by bedevere-appbot
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When built on a MIPS architecture,_MIPS_SIM is used to determine
architecture specifics. The value is expected to match either
_ABIO32,_ABIN32 or_ABI64.

Ingcc config/mips/mips.h these values are defined as compiler
builtin_define inside of a switch/case. That means, mips64el and
mips64 architectures know about_ABI64 but don't know about_ABIO32
and_ABIN32. In turn, when CPython tries to use them in comparison,
they may be undefined identifiers.

In default compiler behavior, the undefined identifier will be
evaluated as zero, and it will not match_MIPS_SIM. However, the
issues pop up when-Wundef (or, even worse,-Werror=undef) compiler
flag is enabled. Then suddenly it's visible as a warning or error.
(cherry picked from commit6985e2e)

Co-authored-by: Valters Jansonssigv@users.noreply.github.com

Issue:_MIPS_SIM comparison may contain undefined identifiers for _ABI #132026

pythongh-132026: Ensure _MIPS_SIM has defined _ABI identifiers for co…

7735662

…mparison (pythonGH-132027)When built on a MIPS architecture, `_MIPS_SIM` is used to determinearchitecture specifics. The value is expected to match either`_ABIO32`, `_ABIN32` or `_ABI64`.In `gcc` config/mips/mips.h these values are defined as compiler`builtin_define` inside of a switch/case. That means, mips64el andmips64 architectures know about `_ABI64` but don't know about `_ABIO32`and `_ABIN32`. In turn, when CPython tries to use them in comparison,they may be undefined identifiers.In default compiler behavior, the undefined identifier will beevaluated as zero, and it will not match `_MIPS_SIM`. However, theissues pop up when `-Wundef` (or, even worse, `-Werror=undef`) compilerflag is enabled. Then suddenly it's visible as a warning or error.(cherry picked from commit6985e2e)Co-authored-by: Valters Jansons <sigv@users.noreply.github.com>