Re: [PATCH] LoongArch: Add soft floating-point fe* function implementations.

[caiyinyu <caiyinyu@loongson.cn>]

在 2024/4/1 下午9:19, Florian Weimer 写道:
>> This patch accomplishes the following:
>> 1. Implements soft floating-point functions to enhance compatibility and
>>    flexibility in environments without hardware floating-point support.
>> 2. Refactors macro definitions by moving them from `fenv_libc.h` to
>>    `fpu_control.h`. This change not only simplifies the codebase but also
>>    eliminates the need for the unexported header file `fenv_libc.h`,
>>    streamlining the inclusion of floating-point utilities across different
>>    modules.
> This patch appears to add a new ABI.  The commit message doesn't mention
> this, and it probably needs a NEWS update, too.
>
> The new ABI is backdated to glibc 2.36.  For new ABIs, we would expect a
> glibc 2.40 baseline, but this is not a hard technical requirement.


The LoongArch soft ABI was added to glibc in version 2.37[1], but it was 
not fully implemented,
lacking functions for handling soft float exceptions/rounding modes. 
This patch fills in
the missing functions and fixes related failed test cases.
Therefore, would backporting this patch to 2.37 be sufficient?

I will update the NEWS (if necessary) and
the commit message of this patch in the v3 version of the patch as follows:

diff --git a/NEWS b/NEWS
index da4b2223e9..b64607ff57 100644
--- a/NEWS
+++ b/NEWS
@@ -26,6 +26,11 @@ Major new features:
    more extensive verification tests for AT_SECURE programs and not 
meant to
    be a security feature.

+* Added missing functions for handling soft float exceptions/rounding modes
+  in the LoongArch soft ABI. The LoongArch soft ABI was introduced in 
version
+  2.37 of glibc, but it did not include comprehensive support for soft 
float
+  exceptions/rounding modes.
+
  Deprecated and removed features, and other changes affecting 
compatibility:

    [Add deprecations, removals and changes affecting compatibility here]


commit info:

     LoongArch: Add soft floating-point fe* function implementations.

     This patch accomplishes the following:
     1. Implements soft floating-point functions to enhance 
compatibility and
       flexibility in environments without hardware floating-point support.
     2. Refactors macro definitions by moving them from `fenv_libc.h` to
       `fpu_control.h`. This change not only simplifies the codebase but 
also
       eliminates the need for the unexported header file `fenv_libc.h`,
       streamlining the inclusion of floating-point utilities across 
different
       modules.

     The LoongArch soft ABI was introduced in version 2.37 of glibc, but 
it did
     not include comprehensive support for soft float 
exceptions/rounding modes.
     This commit added missing functions for handling soft float 
exceptions/rounding
     modes in the LoongArch soft ABI and fixes related failed test cases.

     Signed-off-by: caiyinyu <caiyinyu@loongson.cn>

[1]
commit 930993921f2f381b545ea1b1f2d9c534b2b72b08
Author: caiyinyu <caiyinyu@loongson.cn>
Date:   Mon Aug 22 16:00:51 2022 +0800

     LoongArch: Add soft float support.


  scripts/build-many-glibcs.py                      |  4 ++++
  sysdeps/loongarch/Makefile                        |  8 --------
  sysdeps/loongarch/__longjmp.S                     |  2 ++
  sysdeps/loongarch/bits/setjmp.h                   |  3 +++
  sysdeps/loongarch/dl-trampoline.S                 | 11 +++++++++--
  sysdeps/loongarch/fpu_control.h                   | 13 +++++++++++++
  sysdeps/loongarch/nofpu/Implies                   |  1 +
  sysdeps/loongarch/nofpu/math-tests-exceptions.h   | 28 
++++++++++++++++++++++++++++
  sysdeps/loongarch/nofpu/math-tests-rounding.h     | 27 
+++++++++++++++++++++++++++
  sysdeps/loongarch/preconfigure                    |  1 -
  sysdeps/loongarch/preconfigure.ac                 |  1 -
  sysdeps/loongarch/setjmp.S                        |  2 ++
  sysdeps/unix/sysv/linux/loongarch/Makefile        |  9 +++++++++
  sysdeps/unix/sysv/linux/loongarch/configure       | 51 
++++++++++++++++++++++++++++++++++++++++++++++++---
  sysdeps/unix/sysv/linux/loongarch/configure.ac    | 22 
+++++++++++++++++++---
  sysdeps/unix/sysv/linux/loongarch/ldd-rewrite.sed |  2 +-
  sysdeps/unix/sysv/linux/loongarch/shlib-versions  |  2 ++

> Thanks,
> Florian