Subject: Re: Powerpc on core-updates

From: Andreas Enge <[email-masked]>
Date: Thu, 13 Apr 2023 11:51:51 +0200

I may as well try to provide a patch. It is untested even on x86_64,
since it requires quite a few rebuilds. If it works on powerpc, it should
probably be made conditional on the architecture to avoid a world rebuild.
I do not know whether this is possible in the patches field in an origin.

Andreas

>From 5eb50bdc34759d4c917f2143e037fad62bc08ed7 Mon Sep 17 00:00:00 2001
From: Andreas Enge <[email-masked]>
Date: Thu, 13 Apr 2023 11:46:47 +0200
Subject: [PATCH] gnu: gcc-11: Fix build on powerpc64le.

* gnu/packages/patches/gcc-11-libstdc++-powerpc.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register patch.
* gnu/packages/gcc.scm (gcc-11)[origin]: Use patch.
---
 gnu/local.mk                                   |  1 +
 gnu/packages/gcc.scm                           |  5 +++--
 .../patches/gcc-11-libstdc++-powerpc.patch     | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 gnu/packages/patches/gcc-11-libstdc++-powerpc.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index b07811f1cb..1255846462 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1184,6 +1184,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gcc-11-libstdc++-hurd-libpthread.patch   \
   %D%/packages/patches/gcc-12-cross-environment-variables.patch \
   %D%/packages/patches/gcc-10-tree-sra-union-handling.patch	\
+  %D%/packages/patches/gcc-11-libstdc++-powerpc.patch           \
   %D%/packages/patches/gcolor3-update-libportal-usage.patch	\
   %D%/packages/patches/gd-fix-tests-on-i686.patch		\
   %D%/packages/patches/gd-brect-bounds.patch			\
diff --git a/gnu/packages/gcc.scm b/gnu/packages/gcc.scm
index a511cdbc45..631e08db25 100644
--- a/gnu/packages/gcc.scm
+++ b/gnu/packages/gcc.scm
@@ -2,7 +2,7 @@
 ;;; Copyright © 2012-2023 Ludovic Courtès <[email-masked]>
 ;;; Copyright © 2014, 2015, 2018 Mark H Weaver <[email-masked]>
 ;;; Copyright © 2014, 2015, 2016, 2017, 2019, 2021 Ricardo Wurmus <[email-masked]>
-;;; Copyright © 2015 Andreas Enge <[email-masked]>
+;;; Copyright © 2015, 2023 Andreas Enge <[email-masked]>
 ;;; Copyright © 2015-2018, 2020-2023 Efraim Flashner <[email-masked]>
 ;;; Copyright © 2016 Carlos Sánchez de La Lama <[email-masked]>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <[email-masked]>
@@ -703,7 +703,8 @@ (define-public gcc-11
               "0fdclcwf728wbq52vphfcjywzhpsjp3kifzj3pib3xcihs0z4z5l"))
             (patches (search-patches "gcc-9-strmov-store-file-names.patch"
                                      "gcc-5.0-libvtv-runpath.patch"
-                                     "gcc-10-tree-sra-union-handling.patch"))
+                                     "gcc-10-tree-sra-union-handling.patch"
+                                     "gcc-11-libstdc++-powerpc.patch"))
             (modules '((guix build utils)))
             (snippet gcc-canadian-cross-objdump-snippet)))
    (arguments
diff --git a/gnu/packages/patches/gcc-11-libstdc++-powerpc.patch b/gnu/packages/patches/gcc-11-libstdc++-powerpc.patch
new file mode 100644
index 0000000000..aff2ef16f1
--- /dev/null
+++ b/gnu/packages/patches/gcc-11-libstdc++-powerpc.patch
@@ -0,0 +1,18 @@
+diff -u -r gcc-11.3.0.alt/libstdc++-v3/src/c++17/floating_from_chars.cc gcc-11.3.0/libstdc++-v3/src/c++17/floating_from_chars.cc
+--- gcc-11.3.0.alt/libstdc++-v3/src/c++17/floating_from_chars.cc	2023-04-13 11:36:08.169841428 +0200
++++ gcc-11.3.0/libstdc++-v3/src/c++17/floating_from_chars.cc	2023-04-13 11:36:54.825827304 +0200
+@@ -495,8 +495,14 @@
+ from_chars(const char* first, const char* last, __ieee128& value,
+ 	   chars_format fmt) noexcept
+ {
++#if _GLIBCXX_USE_CXX11_ABI
+   buffer_resource mr;
+   pmr::string buf(&mr);
++#else
++  string buf;
++  if (!reserve_string(buf))
++    return make_result(first, 0, {}, ec);
++#endif
+   size_t len = 0;
+   errc ec = errc::invalid_argument;
+   __try
-- 
2.39.2