Substantially reduce instantiations and debug size of std::function
std::function uses a standard allocator to manage its memory, however
standard allocators are templates and using them correctly requires
a stupid amount of instantiations. This leads to a substantial increase
in debug info and object sizes.
This patch addresses the issue by dropping the allocator when possible
and using raw new and delete to get memory.
This change decreases the object file size for the test func.wrap.func.con/F.pass.cpp by 33% and the final binary by 29% (when compiled with -g -ggnu-pubnames -gpubnames).
It also roughly halfs the number of entries in the pubnames and pubtype
sections.
llvm-svn: 362865
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: d63dd874ecbdcbc9bdcfc4fde4e372ad2f605ba5
diff --git a/include/functional b/include/functional
index 2cec0ea..e2eac0e 100644
--- a/include/functional
+++ b/include/functional
@@ -1479,6 +1479,8 @@
// __alloc_func holds a functor and an allocator.
template <class _Fp, class _Ap, class _FB> class __alloc_func;
+template <class _Fp, class _FB>
+class __default_alloc_func;
template <class _Fp, class _Ap, class _Rp, class... _ArgTypes>
class __alloc_func<_Fp, _Ap, _Rp(_ArgTypes...)>
@@ -1548,6 +1550,56 @@
_LIBCPP_INLINE_VISIBILITY
void destroy() _NOEXCEPT { __f_.~__compressed_pair<_Target, _Alloc>(); }
+
+ static void __destroy_and_delete(__alloc_func* __f) {
+ typedef allocator_traits<_Alloc> __alloc_traits;
+ typedef typename __rebind_alloc_helper<__alloc_traits, __alloc_func>::type
+ _FunAlloc;
+ _FunAlloc __a(__f->__get_allocator());
+ __f->destroy();
+ __a.deallocate(__f, 1);
+ }
+};
+
+template <class _Fp, class _Rp, class... _ArgTypes>
+class __default_alloc_func<_Fp, _Rp(_ArgTypes...)> {
+ _Fp __f_;
+
+public:
+ typedef _Fp _Target;
+
+ _LIBCPP_INLINE_VISIBILITY
+ const _Target& __target() const { return __f_; }
+
+ _LIBCPP_INLINE_VISIBILITY
+ explicit __default_alloc_func(_Target&& __f) : __f_(std::move(__f)) {}
+
+ _LIBCPP_INLINE_VISIBILITY
+ explicit __default_alloc_func(const _Target& __f) : __f_(__f) {}
+
+ _LIBCPP_INLINE_VISIBILITY
+ _Rp operator()(_ArgTypes&&... __arg) {
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_, _VSTD::forward<_ArgTypes>(__arg)...);
+ }
+
+ _LIBCPP_INLINE_VISIBILITY
+ __default_alloc_func* __clone() const {
+ __builtin_new_allocator::__holder_t __hold =
+ __builtin_new_allocator::__allocate_type<__default_alloc_func>(1);
+ __default_alloc_func* __res =
+ ::new (__hold.get()) __default_alloc_func(__f_);
+ (void)__hold.release();
+ return __res;
+ }
+
+ _LIBCPP_INLINE_VISIBILITY
+ void destroy() _NOEXCEPT { __f_.~_Target(); }
+
+ static void __destroy_and_delete(__default_alloc_func* __f) {
+ __f->destroy();
+ __builtin_new_allocator::__deallocate_type<__default_alloc_func>(__f, 1);
+ }
};
// __base provides an abstract interface for copyable functors.
@@ -1696,7 +1748,7 @@
__value_func() _NOEXCEPT : __f_(0) {}
template <class _Fp, class _Alloc>
- _LIBCPP_INLINE_VISIBILITY __value_func(_Fp&& __f, const _Alloc __a)
+ _LIBCPP_INLINE_VISIBILITY __value_func(_Fp&& __f, const _Alloc& __a)
: __f_(0)
{
typedef allocator_traits<_Alloc> __alloc_traits;
@@ -1724,6 +1776,11 @@
}
}
+ template <class _Fp,
+ class = typename enable_if<!is_same<typename decay<_Fp>::type, __value_func>::value>::type>
+ _LIBCPP_INLINE_VISIBILITY explicit __value_func(_Fp&& __f)
+ : __value_func(std::forward<_Fp>(__f), allocator<_Fp>()) {}
+
_LIBCPP_INLINE_VISIBILITY
__value_func(const __value_func& __f)
{
@@ -1923,29 +1980,22 @@
return __f->__clone();
}
- template <typename _Fun> static void __large_destroy(void* __s)
- {
- typedef allocator_traits<typename _Fun::_Alloc> __alloc_traits;
- typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
- _FunAlloc;
- _Fun* __f = static_cast<_Fun*>(__s);
- _FunAlloc __a(__f->__get_allocator());
- __f->destroy();
- __a.deallocate(__f, 1);
+ template <typename _Fun>
+ static void __large_destroy(void* __s) {
+ _Fun::__destroy_and_delete(static_cast<_Fun*>(__s));
}
template <typename _Fun>
_LIBCPP_INLINE_VISIBILITY static const __policy*
- __choose_policy(/* is_small = */ false_type)
- {
- static const _LIBCPP_CONSTEXPR __policy __policy_ = {
- &__large_clone<_Fun>, &__large_destroy<_Fun>, false,
+ __choose_policy(/* is_small = */ false_type) {
+ static const _LIBCPP_CONSTEXPR __policy __policy_ = {
+ &__large_clone<_Fun>, &__large_destroy<_Fun>, false,
#ifndef _LIBCPP_NO_RTTI
- &typeid(typename _Fun::_Target)
+ &typeid(typename _Fun::_Target)
#else
- nullptr
+ nullptr
#endif
- };
+ };
return &__policy_;
}
@@ -2070,6 +2120,25 @@
}
}
+ template <class _Fp, class = typename enable_if<!is_same<typename decay<_Fp>::type, __policy_func>::value>::type>
+ _LIBCPP_INLINE_VISIBILITY explicit __policy_func(_Fp&& __f)
+ : __policy_(__policy::__create_empty()) {
+ typedef __default_alloc_func<_Fp, _Rp(_ArgTypes...)> _Fun;
+
+ if (__function::__not_null(__f)) {
+ __invoker_ = __invoker::template __create<_Fun>();
+ __policy_ = __policy::__create<_Fun>();
+ if (__use_small_storage<_Fun>()) {
+ ::new ((void*)&__buf_.__small) _Fun(_VSTD::move(__f));
+ } else {
+ __builtin_new_allocator::__holder_t __hold =
+ __builtin_new_allocator::__allocate_type<_Fun>(1);
+ __buf_.__large = ::new (__hold.get()) _Fun(_VSTD::move(__f));
+ (void)__hold.release();
+ }
+ }
+ }
+
_LIBCPP_INLINE_VISIBILITY
__policy_func(const __policy_func& __f)
: __buf_(__f.__buf_), __invoker_(__f.__invoker_),
@@ -2290,8 +2359,7 @@
template <class _Rp, class... _ArgTypes>
template <class _Fp, class>
-function<_Rp(_ArgTypes...)>::function(_Fp __f)
- : __f_(_VSTD::move(__f), allocator<_Fp>()) {}
+function<_Rp(_ArgTypes...)>::function(_Fp __f) : __f_(_VSTD::move(__f)) {}
#if _LIBCPP_STD_VER <= 14
template <class _Rp, class... _ArgTypes>