Re: Trunk patches required for gcc-6-branch to build for msp430

[Jozef Lawrynowicz <jozef dot l at somniumtech dot com>]

The gcc-6-branch at the current upstream revision (r246561) doesn't
build when configured with the following options: "--target=msp430-elf
--enable-languages=c,c++"

The gcc-5-branch does build with these options.

Backporting r244727 and r243310 to the gcc-6-branch fixes the two
build issues, so the build completes successfully. The patches are at
the end of this message.
I don't have write access to the GCC repository, so would appreciate
if someone could backport these patches for me.

The error message when building GCC on the gcc-6-branch:

    checking how size_t is mangled... x
    configure: error: Unknown underlying type for size_t
    make[1]: *** [configure-target-libstdc++-v3] Error 1
    make[1]: Leaving directory `/srv/net/msp430/jozefl/gcc/build'
    make: *** [all] Error 2

Applying r244727 fixes this configure error. Discussion on this patch
is here: https://gcc.gnu.org/ml/gcc-patches/2017-01/msg01448.html

Rebuilding results in this new error:

../../../../../libstdc++-v3/src/c++11/cow-stdexcept.cc: In function
âvoid* txnal_read_ptr(void* const*)â:
../../../../../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*)
   ^~~~~~~~~~~~~
make[4]: *** [cow-stdexcept.lo] Error 1

Applying r243310 fixes this build error. Discussion on this patch is
here: https://gcc.gnu.org/ml/gcc-patches/2016-11/msg00950.html

GCC now builds successfully builds successfully:

Target: msp430-elf
Configured with: ../configure --target=msp430-elf --enable-languages=c,c++
Thread model: single
gcc version 6.3.1 20170329 (GCC)

The 2 patches are below, I verified GCC builds successfully for
x86_64-unknown-linux-gnu with both applied.

From b5aacd74cdd4209f28309d38d85cb0004cc93410 Mon Sep 17 00:00:00 2001

From: Jozef Lawrynowicz <jozef.l@somniumtech.com>
Date: Thu, 30 Mar 2017 15:46:26 +0000
Subject: [PATCH 1/2] Backport r244727

2017-01-20  Joe Seymour  <joe.s@somniumtech.com>

* acinclude.m4 (GLIBCXX_CHECK_SIZE_T_MANGLING): Support uint20_t.
* configure: Regenerate.

---
 libstdc++-v3/acinclude.m4 |  8 ++++++--
 libstdc++-v3/configure    | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 0576560..e48cf96 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -4468,8 +4468,12 @@ AC_DEFUN([GLIBCXX_CHECK_SIZE_T_MANGLING], [
                        [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])
+                         [glibcxx_cv_size_t_mangling=t], [
+            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 b5ae421..f8635f8 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -80555,6 +80555,21 @@ _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
   glibcxx_cv_size_t_mangling=t
 else
+
+            cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+extern __SIZE_TYPE__ x; extern __int20 unsigned x;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  glibcxx_cv_size_t_mangling=u6uint20
+else
   glibcxx_cv_size_t_mangling=x
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
@@ -80569,6 +80584,9 @@ fi
 rm -f core conftest.err conftest.$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
-- 
2.9.3

=============

From: Jozef Lawrynowicz <jozef.l@somniumtech.com>
Date: Thu, 30 Mar 2017 15:42:26 +0000
Subject: [PATCH 2/2] Backport r243310

Added #ifdef case for when void* is 16 bits so it compiles in AVR
target.

2016-12-06  Felipe Magno de Almeida  <felipe@expertisesolutions.com.br>

* src/c++11/cow-stdexcept.cc: Add special case for 16 bit pointers.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@243310
138bc75d-0d04-0410-961f-82ee72b054a4
---
 libstdc++-v3/src/c++11/cow-stdexcept.cc | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/src/c++11/cow-stdexcept.cc
b/libstdc++-v3/src/c++11/cow-stdexcept.cc
index 31a89df..641b372 100644
--- a/libstdc++-v3/src/c++11/cow-stdexcept.cc
+++ b/libstdc++-v3/src/c++11/cow-stdexcept.cc
@@ -208,6 +208,8 @@ extern void* _ZGTtnaX (size_t sz) __attribute__((weak));
 extern void _ZGTtdlPv (void* ptr) __attribute__((weak));
 extern uint8_t _ITM_RU1(const uint8_t *p)
   ITM_REGPARM __attribute__((weak));
+extern uint16_t _ITM_RU2(const uint16_t *p)
+  ITM_REGPARM __attribute__((weak));
 extern uint32_t _ITM_RU4(const uint32_t *p)
   ITM_REGPARM __attribute__((weak));
 extern uint64_t _ITM_RU8(const uint64_t *p)
@@ -272,12 +274,15 @@ _txnal_cow_string_C1_for_exceptions(void* that,
const char* s,
 static void* txnal_read_ptr(void* const * ptr)
 {
   static_assert(sizeof(uint64_t) == sizeof(void*)
- || sizeof(uint32_t) == sizeof(void*),
- "Pointers must be 32 bits or 64 bits wide");
+ || sizeof(uint32_t) == sizeof(void*)
+ || sizeof(uint16_t) == sizeof(void*),
+ "Pointers must be 16 bits, 32 bits or 64 bits wide");
 #if __UINTPTR_MAX__ == __UINT64_MAX__
   return (void*)_ITM_RU8((const uint64_t*)ptr);
-#else
+#elif __UINTPTR_MAX__ == __UINT32_MAX__
   return (void*)_ITM_RU4((const uint32_t*)ptr);
+#else
+  return (void*)_ITM_RU2((const uint16_t*)ptr);
 #endif
 }

-- 
2.9.3


On 21 March 2017 at 17:57, Jozef Lawrynowicz <jozef.l@somniumtech.com> wrote:
> r244727 and r243310 from the gcc trunk are needed in the gcc-6-branch
> to build gcc for the msp430 target with C and C++ support.
>
> Would it be possible for these patches to be backported to the
> gcc-6-branch? The gcc-5-branch builds for msp430 with C and C++
> support, so isn't this technically a regression?



-- 
Jozef Lawrynowicz
Software Engineer
SOMNIUM Technologies
www.somniumtech.com