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From ffb10db6fa080e4c225e16928aec052d4c0baa95 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Fri, 2 Sep 2022 23:07:05 -0700
Subject: [PATCH] Allow default libc to be specified to configure
The default C library is normally computed based on the target
triplet. However, for embedded systems, it can be useful to leave the
triplet alone while changing which C library is used by default. Other
C libraries may still be available on the system so the compiler and
can be used by specifying suitable include and library paths at build
time.
If an unknown --with-default-libc= value is provided, emit an error
and stop.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
gcc/config.gcc | 48 ++++++++++++++++++++++++++++++++++++++++--------
gcc/configure.ac | 4 ++++
2 files changed, 44 insertions(+), 8 deletions(-)
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -664,6 +664,8 @@
# Common C libraries.
tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3 LIBC_MUSL=4"
+default_libc=""
+
# 32-bit x86 processors supported by --with-arch=. Each processor
# MUST be separated by exactly one space.
x86_archs="athlon athlon-4 athlon-fx athlon-mp athlon-tbird \
@@ -870,16 +872,16 @@
esac
case $target in
*-*-*android*)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_BIONIC"
+ default_libc=LIBC_BIONIC
;;
*-*-*uclibc* | *-*-uclinuxfdpiceabi)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
+ default_libc=LIBC_UCLIBC
;;
*-*-*musl*)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_MUSL"
+ default_libc=LIBC_MUSL
;;
*)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
+ default_libc=LIBC_GLIBC
;;
esac
# Assume that glibc or uClibc or Bionic are being used and so __cxa_atexit
@@ -988,7 +990,8 @@
case ${enable_threads} in
"" | yes | posix) thread_file='posix' ;;
esac
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC SINGLE_LIBC"
+ tm_defines="$tm_defines SINGLE_LIBC"
+ default_libc=LIBC_UCLIBC
;;
*-*-rdos*)
use_gcc_stdint=wrap
@@ -1652,13 +1655,13 @@
case ${target} in
csky-*-linux-gnu*)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
+ default_libc=LIBC_GLIBC
# Force .init_array support. The configure script cannot always
# automatically detect that GAS supports it, yet we require it.
gcc_cv_initfini_array=yes
;;
csky-*-linux-uclibc*)
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
+ default_libc=LIBC_UCLIBC
default_use_cxa_atexit=no
;;
*)
@@ -3038,7 +3041,7 @@
tmake_file="${tmake_file} t-linux rs6000/t-linux64 rs6000/t-fprules rs6000/t-ppccomm"
tmake_file="${tmake_file} rs6000/t-vxworks"
- tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
+ default_libc=LIBC_GLIBC
extra_objs="$extra_objs linux.o rs6000-linux.o"
;;
powerpc-wrs-vxworks*)
@@ -5879,3 +5882,32 @@
fi
;;
esac
+
+case "${with_default_libc}" in
+glibc)
+ default_libc=LIBC_GLIBC
+ ;;
+uclibc)
+ default_libc=LIBC_UCLIBC
+ ;;
+bionic)
+ default_libc=LIBC_BIONIC
+ ;;
+musl)
+ default_libc=LIBC_MUSL
+ ;;
+"")
+ ;;
+*)
+ echo "Unknown libc in --with-default-libc=$with_default_libc" 1>&2
+ exit 1
+ ;;
+esac
+
+case "$default_libc" in
+"")
+ ;;
+*)
+ tm_defines="$tm_defines DEFAULT_LIBC=$default_libc"
+ ;;
+esac
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -2502,6 +2502,10 @@
fi
AC_SUBST(inhibit_libc)
+AC_ARG_WITH(default-libc,
+ [AS_HELP_STRING([--with-default-libc],
+ [Use specified default C library])])
+
# When building gcc with a cross-compiler, we need to adjust things so
# that the generator programs are still built with the native compiler.
# Also, we cannot run fixincludes.
|
