[Bug libstdc++/69310] [6 Regression] Revision r232454 breaks bootstrap on x86_64-apple-darwin15

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69310

--- Comment #8 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
(In reply to torvald from comment #7)
> Does this patch fix the issue on Darwin?
> https://gcc.gnu.org/ml/gcc-patches/2016-01/msg01452.html

The proposed patch for libstdc++-v3/src/c++11/cow-stdexcept.cc is incomplete.
You missed the additional required change of...

@@ -385,7 +387,7 @@
 }                                                                      \
 void                                                                   \
 _ZGTtNSt##NAME##C2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \
-    CLASS*, const std::__sso_string&) __attribute__((alias             \
+    CLASS*, const std::__sso_string&) __attribute__((weak, alias              
\
 ("_ZGTtNSt" #NAME                                                      \
   "C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE")));      \
 void                                                                   \

Note however that the compilation of libstdc++-v3/src/c++11/cow-stdexcept.cc on
x86_64-apple-darwin15 does produce warnings of the form...

warning: alias definitions not supported in Mach-O; ignored

and then the bootstrap fails later at...

make[3]: Nothing to be done for `all'.
/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/./prev-gcc/xg++
-B/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/./prev-gcc/
-B/sw/lib/gcc6/x86_64-apple-darwin15.4.0/bin/ -nostdinc++
-B/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/src/.libs
-B/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/libsupc++/.libs

-I/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/include/x86_64-apple-darwin15.4.0

-I/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/include
 -I/sw/src/fink.build/gcc6-6.0.0-1/gcc-6-20160119/libstdc++-v3/libsupc++
-L/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/src/.libs
-L/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/prev-x86_64-apple-darwin15.4.0/libstdc++-v3/libsupc++/.libs
  -g -O2   -gtoggle -DIN_GCC     -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic
-Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common
 -DHAVE_CONFIG_H -DGENERATOR_FILE -fno-PIE -static-libstdc++ -static-libgcc
-Wl,-no_pie  -o build/genpreds \
            build/genpreds.o build/rtl.o build/read-rtl.o build/ggc-none.o
build/vec.o build/min-insn-modes.o build/gensupport.o build/print-rtl.o
build/hash-table.o build/read-md.o build/errors.o .././libiberty/libiberty.a
Undefined symbols for architecture x86_64:
  "__ITM_RU1", referenced from:
      _txnal_cow_string_C1_for_exceptions(void*, char const*, void*) in
libstdc++.a(cow-stdexcept.o)
  "__ITM_RU8", referenced from:
      _txnal_cow_string_c_str(void const*) in libstdc++.a(cow-stdexcept.o)
      _txnal_sso_string_c_str(void const*) in libstdc++.a(cow-stdexcept.o)
      _txnal_cow_string_D1(void*) in libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::logic_error::logic_error(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::logic_error::what() const in
libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::domain_error::domain_error(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::invalid_argument::invalid_argument(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      ...
  "__ITM_addUserCommitAction", referenced from:
      _txnal_cow_string_D1(void*) in libstdc++.a(cow-stdexcept.o)
  "__ITM_memcpyRnWt", referenced from:
      transaction clone for std::logic_error::logic_error(char const*) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::logic_error::logic_error(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::domain_error::domain_error(char const*) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::domain_error::domain_error(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::invalid_argument::invalid_argument(char
const*) in libstdc++.a(cow-stdexcept.o)
      transaction clone for
std::invalid_argument::invalid_argument(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::length_error::length_error(char const*) in
libstdc++.a(cow-stdexcept.o)
      ...
  "__ITM_memcpyRtWn", referenced from:
      _txnal_cow_string_C1_for_exceptions(void*, char const*, void*) in
libstdc++.a(cow-stdexcept.o)
  "transaction clone for operator delete(void*)", referenced from:
      transaction clone for std::logic_error::~logic_error() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::domain_error::~domain_error() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::invalid_argument::~invalid_argument() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::length_error::~length_error() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::out_of_range::~out_of_range() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::runtime_error::~runtime_error() in
libstdc++.a(cow-stdexcept.o)
      transaction clone for std::range_error::~range_error() in
libstdc++.a(cow-stdexcept.o)
      ...
  "transaction clone for operator new[](unsigned long)", referenced from:
      _txnal_cow_string_C1_for_exceptions(void*, char const*, void*) in
libstdc++.a(cow-stdexcept.o)
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
make[3]: *** [build/genpreds] Error 1
make[2]: *** [all-stage2-gcc] Error 2
make[1]: *** [stage2-bubble] Error 2
make: *** [bootstrap] Error 2