From: Keith Packard <keithp@keithp.com>
To: gcc@gcc.gnu.org
Cc: gcc-patches@gcc.gnu.org, Keith Packard <keithp@keithp.com>
Subject: [PATCH 1/3] picolibc: Allow default libc to be specified to configure
Date: Wed, 24 Aug 2022 11:04:24 -0700 [thread overview]
Message-ID: <20220824180426.820576-2-keithp@keithp.com> (raw)
In-Reply-To: <20220824180426.820576-1-keithp@keithp.com>
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.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
gcc/config.gcc | 42 ++++++++++++++++++++++++++++++++++--------
gcc/configure.ac | 4 ++++
2 files changed, 38 insertions(+), 8 deletions(-)
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 02f58970db0..f8b6da4f4e7 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -641,6 +641,8 @@ esac
# 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 \
@@ -847,16 +849,16 @@ case ${target} in
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
@@ -949,7 +951,8 @@ case ${target} in
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
@@ -1606,13 +1609,13 @@ csky-*-*)
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="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
+ default_libc=LIBC_UCLIBC
default_use_cxa_atexit=no
;;
*)
@@ -3065,7 +3068,7 @@ powerpc*-wrs-vxworks7r*)
tmake_file="${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="$extra_objs linux.o rs6000-linux.o"
;;
powerpc-wrs-vxworks*)
@@ -5861,3 +5864,26 @@ i[34567]86-*-* | x86_64-*-*)
fi
;;
esac
+
+case "${with_default_libc}" in
+glibc)
+ default_libc=LIBC_GLIBC
+ ;;
+uclibc)
+ default_libc=LIBC_UCLIBC
+ ;;
+bionic)
+ default_libc=LIBC_BIONIC
+ ;;
+musl)
+ default_libc=LIBC_MUSL
+ ;;
+esac
+
+case "$default_libc" in
+"")
+ ;;
+*)
+ tm_defines="$tm_defines DEFAULT_LIBC=$default_libc"
+ ;;
+esac
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 819b490d1b6..0b76613b635 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -2490,6 +2490,10 @@ if { { test x$host != x$target && test "x$with_sysroot" = x ; } ||
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.
--
2.36.1
next prev parent reply other threads:[~2022-08-24 18:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 18:04 [PATCH 0/3] picolibc: Add picolibc linking help Keith Packard
2022-08-24 18:04 ` Keith Packard [this message]
2022-08-24 18:04 ` [PATCH 2/3] picolibc: Add newlib and picolibc as default C library choices Keith Packard
2022-08-24 18:04 ` [PATCH 3/3] picolibc: Add '--oslib=' option when default C library is picolibc Keith Packard
2022-08-24 18:24 ` [PATCH 0/3] picolibc: Add picolibc linking help Andrew Pinski
2022-09-02 12:36 ` Richard Sandiford
2022-09-03 6:02 ` Keith Packard
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