[libcxx-commits] [libcxx] [libc++] fix std::make_exception_ptr interaction with ObjC (PR #135386)
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libcxx-commits at lists.llvm.org
Tue May 13 15:11:17 PDT 2025
https://github.com/itrofimow updated https://github.com/llvm/llvm-project/pull/135386
>From 9f88c67d226864bd7df99a3e55d4a4790a8d69fa Mon Sep 17 00:00:00 2001
From: Ivan Trofimov <i.trofimow at yandex.ru>
Date: Fri, 11 Apr 2025 18:23:30 +0300
Subject: [PATCH 1/3] fix std::make_exception_ptr interaction with ObjC
---
libcxx/include/__exception/exception_ptr.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/include/__exception/exception_ptr.h b/libcxx/include/__exception/exception_ptr.h
index dac5b00b57fe3..8b90a6569d136 100644
--- a/libcxx/include/__exception/exception_ptr.h
+++ b/libcxx/include/__exception/exception_ptr.h
@@ -92,7 +92,7 @@ class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
template <class _Ep>
_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
# if _LIBCPP_HAS_EXCEPTIONS
-# if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
+# if !defined(__OBJC__) && _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
using _Ep2 = __decay_t<_Ep>;
void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
>From 764caba12345ab1bc626758d5052c4597cbade62 Mon Sep 17 00:00:00 2001
From: Ivan Trofimov <i.trofimow at yandex.ru>
Date: Mon, 14 Apr 2025 17:17:37 +0300
Subject: [PATCH 2/3] add a comment about __OBJC__ define
---
libcxx/include/__exception/exception_ptr.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/libcxx/include/__exception/exception_ptr.h b/libcxx/include/__exception/exception_ptr.h
index 8b90a6569d136..167aa4d9b367a 100644
--- a/libcxx/include/__exception/exception_ptr.h
+++ b/libcxx/include/__exception/exception_ptr.h
@@ -92,6 +92,7 @@ class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
template <class _Ep>
_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
# if _LIBCPP_HAS_EXCEPTIONS
+ // Clang treats throwing ObjC types differently, and we have to preserve original throw-ing behavior
# if !defined(__OBJC__) && _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
using _Ep2 = __decay_t<_Ep>;
>From 6e108eb698cccec4202d711ae9795fffb53d5ec8 Mon Sep 17 00:00:00 2001
From: Ivan Trofimov <i.trofimow at yandex.ru>
Date: Wed, 14 May 2025 01:11:01 +0300
Subject: [PATCH 3/3] remove the __OBJC__ usage in favor of checking whether
the type thrown is a pointer
---
libcxx/include/__exception/exception_ptr.h | 52 +++++++++++++---------
1 file changed, 32 insertions(+), 20 deletions(-)
diff --git a/libcxx/include/__exception/exception_ptr.h b/libcxx/include/__exception/exception_ptr.h
index 167aa4d9b367a..e0c6fc48b1333 100644
--- a/libcxx/include/__exception/exception_ptr.h
+++ b/libcxx/include/__exception/exception_ptr.h
@@ -15,6 +15,7 @@
#include <__memory/addressof.h>
#include <__memory/construct_at.h>
#include <__type_traits/decay.h>
+#include <__type_traits/is_pointer.h>
#include <cstdlib>
#include <typeinfo>
@@ -92,39 +93,50 @@ class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
template <class _Ep>
_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
# if _LIBCPP_HAS_EXCEPTIONS
+# if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201703L
// Clang treats throwing ObjC types differently, and we have to preserve original throw-ing behavior
-# if !defined(__OBJC__) && _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
- using _Ep2 = __decay_t<_Ep>;
-
- void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
+ // to not break some ObjC invariants. ObjC types are thrown by a pointer, hence the condition;
+ // although it does also trigger for some valid c++ usages, this should be a case rare enough to
+ // not complicate the condition any further
+ if constexpr (std::is_pointer_v<_Ep>) {
+ try {
+ throw __e;
+ } catch (...) {
+ return current_exception();
+ }
+ } else {
+ using _Ep2 = __decay_t<_Ep>;
+
+ void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
# ifdef __wasm__
- // In Wasm, a destructor returns its argument
- (void)__cxxabiv1::__cxa_init_primary_exception(
- __ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) -> void* {
+ // In Wasm, a destructor returns its argument
+ (void)__cxxabiv1::__cxa_init_primary_exception(
+ __ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) -> void* {
# else
- (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) {
+ (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) {
# endif
- std::__destroy_at(static_cast<_Ep2*>(__p));
+ std::__destroy_at(static_cast<_Ep2*>(__p));
# ifdef __wasm__
- return __p;
+ return __p;
# endif
- });
-
- try {
- ::new (__ex) _Ep2(__e);
- return exception_ptr::__from_native_exception_pointer(__ex);
- } catch (...) {
- __cxxabiv1::__cxa_free_exception(__ex);
- return current_exception();
+ });
+
+ try {
+ ::new (__ex) _Ep2(__e);
+ return exception_ptr::__from_native_exception_pointer(__ex);
+ } catch (...) {
+ __cxxabiv1::__cxa_free_exception(__ex);
+ return current_exception();
+ }
}
-# else
+# else // !(_LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201703L)
try {
throw __e;
} catch (...) {
return current_exception();
}
# endif
-# else
+# else // !LIBCPP_HAS_EXCEPTIONS
((void)__e);
std::abort();
# endif
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