76 lines
2.7 KiB
Diff
76 lines
2.7 KiB
Diff
From 365426c28f8bf73d34d77cc06b7d5ffeae17f13a Mon Sep 17 00:00:00 2001
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From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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Date: Tue, 6 Feb 2024 15:33:15 +0100
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Subject: [PATCH] configure.ac: add detection of symver gcc attribute
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On non-ELF platforms, such as microblaze, builds will fail when trying
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to add symver information because __attribute__((symver ..)) is not
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supported even though __has_attribute(__symver__) returns true.
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Support for symver needs to be detected via a compile test since
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__has_attribute can report false positives [0].
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Add a configure compile check for __attribute__((symver ..)) to ensure
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it is supported and define a variable to advertise support.
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[0] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101766#c1
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Upstream: https://git.savannah.nongnu.org/cgit/attr.git/commit/?id=943c776089dbb24ebbfb7432ba9841f1845bf95a
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Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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[Giulio: rework local patch for #if nesting]
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Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
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---
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configure.ac | 15 +++++++++++++++
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libattr/syscalls.c | 8 ++++----
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2 files changed, 19 insertions(+), 4 deletions(-)
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diff --git a/configure.ac b/configure.ac
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index 7e362e9..98477b5 100644
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--- a/configure.ac
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+++ b/configure.ac
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@@ -57,6 +57,21 @@ AS_CASE([$host_os],
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[linux*], [os_linux=yes])
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AM_CONDITIONAL([OS_LINUX], [test "x$os_linux" = "xyes"])
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+AC_CACHE_CHECK(whether __attribute__((__symver__())) is supported,
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+ gcc_cv_symver_attribute,
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+ [cat > conftest.c <<EOF
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+void foo (void) {}
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+__typeof(foo) foo __attribute__ ((__symver__("foo@foo")));
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+EOF
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+ gcc_cv_symver_attribute=no
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+ if ${CC-cc} -Werror -S conftest.c -o conftest.s >/dev/null 2>&1; then \
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+ gcc_cv_symver_attribute=yes
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+ fi
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+ rm -f conftest.[cs]
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+])
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+AS_IF([test $gcc_cv_symver_attribute = yes],
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+ [AC_DEFINE(HAVE_SYMVER_ATTRIBUTE, [], [GCC supports symver attribute])])
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+
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AC_CONFIG_COMMANDS([include/attr],
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[dnl
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rm -rf include/attr
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diff --git a/libattr/syscalls.c b/libattr/syscalls.c
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index 907560a..7ee6d39 100644
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--- a/libattr/syscalls.c
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+++ b/libattr/syscalls.c
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@@ -31,10 +31,10 @@
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* prefer symver attribute if available (since gcc 10),
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* fall back to traditional .symver asm directive otherwise.
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*/
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-#ifdef __has_attribute
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-# if __has_attribute(__symver__)
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-# define SYMVER(cn, vn) __typeof(cn) cn __attribute__((__symver__(vn)))
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-# elif __has_attribute(__no_reorder__)
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+#if defined(HAVE_SYMVER_ATTRIBUTE)
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+# define SYMVER(cn, vn) __typeof(cn) cn __attribute__((__symver__(vn)))
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+#elif defined(__has_attribute)
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+# if __has_attribute(__no_reorder__)
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/*
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* Avoid wrong partitioning with older gcc and LTO. May not work reliably
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* with all versions; use -flto-partition=none if you encounter problems.
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--
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2.34.1
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