../configure --target=msp430-elf --enable-languages=c,c++ && make -j4
Results in the msp430 -mlarge multilib failing to build with...
> configure: error: Unknown underlying type for size_t
> make[1]: *** [configure-target-libstdc++-v3] Error 1
This relates to...
> commit 13143e139230dc4d72710a6c4c312105aeddce4f
> Author: torvald <torvald@138bc75d-0d04-0410-961f-82ee72b054a4>
> Date: Fri Jan 15 22:42:41 2016 +0000
>
> libstdc++: Make certain exceptions transaction_safe.
https://gcc.gnu.org/ml/libstdc++/2016-01/msg00015.html
...which iterates through a list of types at configure time, looking for one
matching __SIZE_TYPE__. The following patch (wip) allows the build to
proceed
(to the next error), by adding __int20 to the list of types to try.
- Is this an acceptable solution?
- There's a comment above GLIBCXX_CHECK_SIZE_T_MANGLING, saying that it was
copied from libitm. Should that be updated too, even if it's
irrelevant for
msp430?
Proceeding past that build error, all multilibs then fail to build with...
> ../../../../../libstdc++-v3/src/c++11/cow-stdexcept.cc:274:3: error:
static assertion failed: Pointers must be 32 bits or 64 bits wide
> static_assert(sizeof(uint64_t) == sizeof(void*)
The assert fails because msp430 has 16-bit or 20-bit pointers. The same
error
can be reproduced for the rl78-elf target, which has 16-bit pointers.
Disabling the original changes for targets with unsupported pointer
sizes seems
like a reasonable solution to me, but I can't see an existing mechanism
to do
so? Do others agree?
More generally, it might be useful to have a mechanism to disable
transactional
memory for some targets. I've observed things like register_tm_clones
taking up
space in ARM Cortex-M binaries. Presumably, this would be achieved by
adding an
--{enable,disable}-transactional-memory argument to configure? I'm happy to
work on a patch, if this is acceptable in principle.
Thanks,
2016-08-XX Joe Seymour <jo...@somniumtech.com>
* acinclude.m4 (GLIBCXX_CHCK_SIZE_T_MANGLING): Try __int20.
* configure: Regenerate.
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index b0f88cb..7332d3e 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -4405,9 +4405,13 @@ AC_DEFUN([GLIBCXX_CHECK_SIZE_T_MANGLING], [
[extern __SIZE_TYPE__ x; extern unsigned long
long x;],
[glibcxx_cv_size_t_mangling=y], [
AC_TRY_COMPILE([],
- [extern __SIZE_TYPE__ x; extern unsigned short
x;],
- [glibcxx_cv_size_t_mangling=t],
- [glibcxx_cv_size_t_mangling=x])
+ [extern __SIZE_TYPE__ x; extern unsigned long
long x;],
+ [glibcxx_cv_size_t_mangling=y], [
+ AC_TRY_COMPILE([],
+ [extern __SIZE_TYPE__ x; extern __int20
unsigned x;],
+ [glibcxx_cv_size_t_mangling=u6uint20],
+ [glibcxx_cv_size_t_mangling=x])
+ ])
])
])
])
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 41797a9..7ab84eb 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -80475,13 +80475,28 @@ else
int
main ()
{
-extern __SIZE_TYPE__ x; extern unsigned short x;
+extern __SIZE_TYPE__ x; extern unsigned long long x;
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
- glibcxx_cv_size_t_mangling=t
+ glibcxx_cv_size_t_mangling=y
+else
+
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+int
+main ()
+{
+extern __SIZE_TYPE__ x; extern __int20 unsigned x;
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+ glibcxx_cv_size_t_mangling=u6uint20
else
glibcxx_cv_size_t_mangling=x
fi
@@ -80497,6 +80512,9 @@ fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
$glibcxx_cv_size_t_mangling" >&5
$as_echo "$glibcxx_cv_size_t_mangling" >&6; }
if test $glibcxx_cv_size_t_mangling = x; then
