On Wed, May 8, 2013 at 6:14 PM, gnubie gnubie <gcc.gnu...@gmail.com> wrote:
> Hi,
> I've noticed odd behaviour when building an ARM compiler with GCC 4.7,
> --with-mode=thumb and multilibs enabled.
>
> If I do a standard c/c++ newlib build with the following multilib options:
> MULTILIB_OPTIONS += marm mthumb
> MULTILIB_DIRNAMES += arm thumb
>
Watch out the difference between "+=" and "=" when hack the Multilib.
When you configure the gcc with --with-mode=thumb, the default mode is
changed to thumb, thus you need to change the "marm" to "mthumb" in
MULTILIB_DEFAULTS.
Here is a small patch that can help you to implement this:
diff --git a/gcc/config/arm/elf.h b/gcc/config/arm/elf.h
index e0a0aa0..d5f2234 100644
--- a/gcc/config/arm/elf.h
+++ b/gcc/config/arm/elf.h
@@ -113,7 +113,7 @@
#ifndef MULTILIB_DEFAULTS
#define MULTILIB_DEFAULTS \
- { "marm", "mlittle-endian", "mfloat-abi=soft",
"mno-thumb-interwork", "fno-leading-underscore" }
+ { "mthumb", "mlittle-endian", "mfloat-abi=soft",
"mno-thumb-interwork", "fno-leading-underscore" }
#endif
^L
#define TARGET_ASM_FILE_START_APP_OFF true
diff --git a/gcc/config/arm/t-arm-elf b/gcc/config/arm/t-arm-elf
index 25b7acb..e7dda60 100644
--- a/gcc/config/arm/t-arm-elf
+++ b/gcc/config/arm/t-arm-elf
@@ -17,7 +17,7 @@
# along with GCC; see the file COPYING3. If not see
# <http://www.gnu.org/licenses/>.
-MULTILIB_OPTIONS = marm/mthumb
+MULTILIB_OPTIONS = marm mthumb
MULTILIB_DIRNAMES = arm thumb
MULTILIB_EXCEPTIONS =
MULTILIB_MATCHES =
@@ -39,9 +39,9 @@ MULTILIB_MATCHES =
# Not quite true. We can support hard-vfp calling in Thumb2, but how do we
# express that here? Also, we really need architecture v5e or later
# (mcrr etc).
-MULTILIB_OPTIONS += mfloat-abi=hard
-MULTILIB_DIRNAMES += fpu
-MULTILIB_EXCEPTIONS += *mthumb/*mfloat-abi=hard*
+#MULTILIB_OPTIONS += mfloat-abi=hard
+#MULTILIB_DIRNAMES += fpu
+#MULTILIB_EXCEPTIONS += *mthumb/*mfloat-abi=hard*
#MULTILIB_EXCEPTIONS += *mcpu=fa526/*mfloat-abi=hard*
#MULTILIB_EXCEPTIONS += *mcpu=fa626/*mfloat-abi=hard*
At least it works for me. Here is what I got:
terguo01@terry-pc01:install-native$ ls arm-none-eabi/lib/
arm libc.a libnosys.a libstdc++.a-gdb.py
linux-crt0.o rdimon.specs redboot.ld
crt0.o libg.a librdimon.a libstdc++.la
linux.specs rdpmon-crt0.o redboot.specs
iq80310.specs libgloss-linux.a librdpmon.a libsupc++.a
pid.specs rdpmon.specs redboot-syscalls.o
ldscripts libm.a libstdc++.a libsupc++.la
rdimon-crt0.o redboot-crt0.o
terguo01@terry-pc01:install-native$ ls arm-none-eabi/lib/arm
crt0.o libgloss-linux.a librdpmon.a libsupc++.a
pid.specs rdpmon.specs redboot-syscalls.o
iq80310.specs libm.a libstdc++.a libsupc++.la
rdimon-crt0.o redboot-crt0.o
libc.a libnosys.a libstdc++.a-gdb.py linux-crt0.o
rdimon.specs redboot.ld
libg.a librdimon.a libstdc++.la linux.specs
rdpmon-crt0.o redboot.specs
BTW. There is an official pre-built tool chain with full
multilib-support for arm-non-eabi at
https://launchpad.net/gcc-arm-embedded.
BR,
Terry
