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| author | Jonathan Wakely <jwakely@redhat.com> | 2022-10-12 23:04:53 +0100 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2022-10-14 15:35:41 +0100 |
| commit | 0dd9dd1fdfca1219bbe3ac460b50c6776b427119 (patch) | |
| tree | d658f3094b09bfea5263f7b42d258232001cf18c | |
| parent | cf0b7e9787c3686c47219a725f2cbcaa19faaaca (diff) | |
| download | gcc-0dd9dd1fdfca1219bbe3ac460b50c6776b427119.zip gcc-0dd9dd1fdfca1219bbe3ac460b50c6776b427119.tar.gz gcc-0dd9dd1fdfca1219bbe3ac460b50c6776b427119.tar.bz2 | |
libstdc++: Disable all emergency EH pool code if obj-count == 0
For a zero-sized static pool we can completely elide all code for the EH
pool.
We no longer need to adjust the static buffer size to ensure at least
one free_entry can be created in it, because we no longer use a static
buffer at all if obj_count == 0. If the buffer exists, obj_count >= 1
and the buffer will be much larger than sizeof(free_entry).
libstdc++-v3/ChangeLog:
* libsupc++/eh_alloc.cc [USE_POOL]: New macro.
[!USE_POOL] (__gnu_cxx::__freeres, pool): Do not define.
[_GLIBCXX_EH_POOL_STATIC] (pool::arena): Do not use std::max.
(__cxxabiv1::__cxa_allocate_exception) [!USE_POOL]: Do not use
pool.
(__cxxabiv1::__cxa_free_exception) [!USE_POOL]: Likewise.
(__cxxabiv1::__cxa_allocate_dependent_exception) [!USE_POOL]:
Likewise.
(__cxxabiv1::__cxa_free_dependent_exception) [!USE_POOL]:
Likewise.
| -rw-r--r-- | libstdc++-v3/libsupc++/eh_alloc.cc | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/libstdc++-v3/libsupc++/eh_alloc.cc b/libstdc++-v3/libsupc++/eh_alloc.cc index 81b8a15..e93f14c 100644 --- a/libstdc++-v3/libsupc++/eh_alloc.cc +++ b/libstdc++-v3/libsupc++/eh_alloc.cc @@ -101,12 +101,21 @@ using namespace __cxxabiv1; #ifdef _GLIBCXX_EH_POOL_NOBJS # if _GLIBCXX_EH_POOL_NOBJS > MAX_OBJ_COUNT # warning "_GLIBCXX_EH_POOL_NOBJS value is too large; ignoring it" +# elif _GLIBCXX_EH_POOL_NOBJS < 0 +# warning "_GLIBCXX_EH_POOL_NOBJS value is negative; ignoring it" # else # undef EMERGENCY_OBJ_COUNT # define EMERGENCY_OBJ_COUNT _GLIBCXX_EH_POOL_NOBJS # endif #endif +#if defined _GLIBCXX_EH_POOL_STATIC && EMERGENCY_OBJ_COUNT == 0 +# define USE_POOL 0 +#else +# define USE_POOL 1 +#endif + +#if USE_POOL namespace __gnu_cxx { void __freeres() noexcept; @@ -161,7 +170,7 @@ namespace #ifdef _GLIBCXX_EH_POOL_STATIC static constexpr std::size_t arena_size = buffer_size_in_bytes(EMERGENCY_OBJ_COUNT, EMERGENCY_OBJ_SIZE); - alignas(void*) char arena[std::max(arena_size, sizeof(free_entry))]; + alignas(void*) char arena[arena_size]; #else char *arena = nullptr; std::size_t arena_size = 0; @@ -374,6 +383,7 @@ namespace __gnu_cxx #endif } } +#endif // USE_POOL extern "C" void * __cxxabiv1::__cxa_allocate_exception(std::size_t thrown_size) noexcept @@ -382,8 +392,10 @@ __cxxabiv1::__cxa_allocate_exception(std::size_t thrown_size) noexcept void *ret = malloc (thrown_size); +#if USE_POOL if (!ret) ret = emergency_pool.allocate (thrown_size); +#endif if (!ret) std::terminate (); @@ -398,9 +410,11 @@ extern "C" void __cxxabiv1::__cxa_free_exception(void *vptr) noexcept { char *ptr = (char *) vptr - sizeof (__cxa_refcounted_exception); +#if USE_POOL if (emergency_pool.in_pool (ptr)) [[__unlikely__]] emergency_pool.free (ptr); else +#endif free (ptr); } @@ -410,8 +424,10 @@ __cxxabiv1::__cxa_allocate_dependent_exception() noexcept { void *ret = malloc (sizeof (__cxa_dependent_exception)); +#if USE_POOL if (!ret) ret = emergency_pool.allocate (sizeof (__cxa_dependent_exception)); +#endif if (!ret) std::terminate (); @@ -426,8 +442,10 @@ extern "C" void __cxxabiv1::__cxa_free_dependent_exception (__cxa_dependent_exception *vptr) noexcept { +#if USE_POOL if (emergency_pool.in_pool (vptr)) [[__unlikely__]] emergency_pool.free (vptr); else +#endif free (vptr); } |