On Wed, 28 Jun 2023 at 08:56, Jan Hubicka wrote: > > I think the __throw_bad_alloc() and __throw_bad_array_new_length() > > functions should always be rare, so marking them cold seems fine (users > who > > define their own allocators that want to throw bad_alloc "often" will > > probably throw it directly, they shouldn't be using our > __throw_bad_alloc() > > function anyway). I don't think __throw_bad_exception is ever used, so > that > > doesn't matter (we could remove it from the header and just keep its > > definition in the library, but there's no big advantage to doing that). > > Others like __throw_length_error() should also be very very rare, and > could > > be marked cold. > > > > Maybe we should just mark everything in <bits/functexcept.h> as cold. If > > users want to avoid the cost of calls to those functions they can do so > by > > checking function preconditions/arguments to avoid the exceptions. There > > are very few places where a throwing libstdc++ API doesn't have a way to > > avoid the exception. The only one that isn't easily avoidable is > > __throw_bad_alloc but OOM should be rare. > > Hi, > this marks everything in functexcept.h as cold and I also noticed that > we probably want to mark as such terminate. > > With fix to 110436 and -O3 we now inline _M_realloc_insert, yay :) > > tested on x86_64-linux, OK? >
OK for trunk, thanks. > > * include/bits/c++config (std::__terminate): Mark cold. > * include/bits/functexcept.h: Mark everything as cold. > * libsupc++/exception: Mark terminate and unexpected as cold. > diff --git a/libstdc++-v3/include/bits/c++config > b/libstdc++-v3/include/bits/c++config > index 009a017b048..dd47f274d5f 100644 > --- a/libstdc++-v3/include/bits/c++config > +++ b/libstdc++-v3/include/bits/c++config > @@ -320,7 +320,7 @@ namespace std > extern "C++" __attribute__ ((__noreturn__, __always_inline__)) > inline void __terminate() _GLIBCXX_USE_NOEXCEPT > { > - void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__)); > + void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ > ((__noreturn__,__cold__)); > terminate(); > } > #pragma GCC visibility pop > diff --git a/libstdc++-v3/include/bits/functexcept.h > b/libstdc++-v3/include/bits/functexcept.h > index 2765f7865df..a2e97413661 100644 > --- a/libstdc++-v3/include/bits/functexcept.h > +++ b/libstdc++-v3/include/bits/functexcept.h > @@ -57,61 +57,61 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > // Helper for exception objects in <typeinfo> > void > - __throw_bad_cast(void) __attribute__((__noreturn__)); > + __throw_bad_cast(void) __attribute__((__noreturn__,__cold__)); > > void > - __throw_bad_typeid(void) __attribute__((__noreturn__)); > + __throw_bad_typeid(void) __attribute__((__noreturn__,__cold__)); > > // Helpers for exception objects in <stdexcept> > void > - __throw_logic_error(const char*) __attribute__((__noreturn__)); > + __throw_logic_error(const char*) __attribute__((__noreturn__,__cold__)); > > void > - __throw_domain_error(const char*) __attribute__((__noreturn__)); > + __throw_domain_error(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_invalid_argument(const char*) __attribute__((__noreturn__)); > + __throw_invalid_argument(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_length_error(const char*) __attribute__((__noreturn__)); > + __throw_length_error(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_out_of_range(const char*) __attribute__((__noreturn__)); > + __throw_out_of_range(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_out_of_range_fmt(const char*, ...) __attribute__((__noreturn__)) > + __throw_out_of_range_fmt(const char*, ...) > __attribute__((__noreturn__,__cold__)) > __attribute__((__format__(__gnu_printf__, 1, 2))); > > void > - __throw_runtime_error(const char*) __attribute__((__noreturn__)); > + __throw_runtime_error(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_range_error(const char*) __attribute__((__noreturn__)); > + __throw_range_error(const char*) __attribute__((__noreturn__,__cold__)); > > void > - __throw_overflow_error(const char*) __attribute__((__noreturn__)); > + __throw_overflow_error(const char*) > __attribute__((__noreturn__,__cold__)); > > void > - __throw_underflow_error(const char*) __attribute__((__noreturn__)); > + __throw_underflow_error(const char*) > __attribute__((__noreturn__,__cold__)); > > // Helpers for exception objects in <ios> > void > - __throw_ios_failure(const char*) __attribute__((__noreturn__)); > + __throw_ios_failure(const char*) __attribute__((__noreturn__,__cold__)); > > void > - __throw_ios_failure(const char*, int) __attribute__((__noreturn__)); > + __throw_ios_failure(const char*, int) > __attribute__((__noreturn__,__cold__)); > > // Helpers for exception objects in <system_error> > void > - __throw_system_error(int) __attribute__((__noreturn__)); > + __throw_system_error(int) __attribute__((__noreturn__,__cold__)); > > // Helpers for exception objects in <future> > void > - __throw_future_error(int) __attribute__((__noreturn__)); > + __throw_future_error(int) __attribute__((__noreturn__,__cold__)); > > // Helpers for exception objects in <functional> > void > - __throw_bad_function_call() __attribute__((__noreturn__)); > + __throw_bad_function_call() __attribute__((__noreturn__,__cold__)); > > #else // ! HOSTED > > diff --git a/libstdc++-v3/libsupc++/exception > b/libstdc++-v3/libsupc++/exception > index a34386e6026..00a6347ebe5 100644 > --- a/libstdc++-v3/libsupc++/exception > +++ b/libstdc++-v3/libsupc++/exception > @@ -75,7 +75,7 @@ namespace std _GLIBCXX_VISIBILITY(default) > > /** The runtime will call this function if %exception handling must be > * abandoned for any reason. It can also be called by the user. */ > - void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__)); > + void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ > ((__noreturn__,__cold__)); > > #if __cplusplus < 201703L || (__cplusplus <= 202002L && > _GLIBCXX_USE_DEPRECATED) > /// If you write a replacement %unexpected handler, it must be of this > type. > @@ -104,7 +104,7 @@ namespace std _GLIBCXX_VISIBILITY(default) > * @deprecated Removed from the C++ standard in C++17 > */ > _GLIBCXX11_DEPRECATED > - void unexpected() __attribute__ ((__noreturn__)); > + void unexpected() __attribute__ ((__noreturn__,__cold__)); > #endif > > /** [18.6.4]/1: 'Returns true after completing evaluation of a > >