libstdc++: Make __cpp_lib_constexpr_exceptions depend on cxx11 ABI

jwakely · jwakely · commit 278eb0a081a3 · 2025-12-17T21:28:57.000Z
The COW std::string is not constexpr, so the &lt;stdexcept&gt; exception
classes can't be constexpr either when they're defined in terms of the
COW string.

While constexpr exceptions for &lt;typeinfo&gt;, &lt;new&gt;, and &lt;exception&gt;
classes would work, __cpp_constexpr_exceptions &gt;= 202411L implies that
everything including &lt;stdexcept&gt; should work. So when we can't support
it fully, we shouldn't announce it.

libstdc++-v3/ChangeLog:

	* include/bits/version.def (constexpr_exceptions): Add
	cxx11abi=yes.
	* include/bits/version.h: Regenerate.
	* testsuite/18_support/exception/version.cc: Require effectiove
	target cxx11_abi.
	* testsuite/18_support/exception_ptr/exception_ptr_cast.cc: Only
	check for constexpr support in cxx11 ABI.
	* testsuite/19_diagnostics/headers/stdexcept/version.cc: Require
	effective target cxx11_abi.
	* testsuite/19_diagnostics/logic_error/constexpr.cc: Likewise.
	* testsuite/19_diagnostics/runtime_error/constexpr.cc: Likewise.
	* testsuite/20_util/expected/version.cc: Only check for
	__cpp_lib_constexpr_exceptions macro for cxx11 ABI.
	* testsuite/20_util/optional/version.cc: Likewise.
	* testsuite/20_util/variant/version.cc: Likewise.

Reviewed-by: Jakub Jelinek &lt;jakub@redhat.com&gt;
diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
@@ -2233,6 +2233,7 @@ ftms = {
     v = 202502;
     cxxmin = 26;
     extra_cond = "__cpp_constexpr_exceptions >= 202411L";
+    cxx11abi = yes;
   };
 };
 
diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
@@ -2497,7 +2497,7 @@
 #undef __glibcxx_want_bitset
 
 #if !defined(__cpp_lib_constexpr_exceptions)
-# if (__cplusplus >  202302L) && (__cpp_constexpr_exceptions >= 202411L)
+# if (__cplusplus >  202302L) && _GLIBCXX_USE_CXX11_ABI && (__cpp_constexpr_exceptions >= 202411L)
 #  define __glibcxx_constexpr_exceptions 202502L
 #  if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_exceptions)
 #   define __cpp_lib_constexpr_exceptions 202502L
diff --git a/libstdc++-v3/testsuite/18_support/exception/version.cc b/libstdc++-v3/testsuite/18_support/exception/version.cc
@@ -1,5 +1,6 @@
 // { dg-do preprocess { target c++26 } }
 // { dg-add-options no_pch }
+// { dg-require-effective-target cxx11_abi }
 
 #include <exception>
 
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/exception_ptr_cast.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/exception_ptr_cast.cc
@@ -78,7 +78,9 @@ constexpr bool test01(bool x)
   return true;
 }
 
+#if _GLIBCXX_USE_CXX11_ABI
 static_assert(test01(false));
+#endif
 
 int main()
 {
diff --git a/libstdc++-v3/testsuite/19_diagnostics/headers/stdexcept/version.cc b/libstdc++-v3/testsuite/19_diagnostics/headers/stdexcept/version.cc
@@ -1,5 +1,6 @@
 // { dg-do preprocess { target c++26 } }
 // { dg-add-options no_pch }
+// { dg-require-effective-target cxx11_abi }
 
 #include <stdexcept>
 
diff --git a/libstdc++-v3/testsuite/19_diagnostics/logic_error/constexpr.cc b/libstdc++-v3/testsuite/19_diagnostics/logic_error/constexpr.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++26 } }
+// { dg-require-effective-target cxx11_abi }
 
 #include <string>
 #include <stdexcept>
diff --git a/libstdc++-v3/testsuite/19_diagnostics/runtime_error/constexpr.cc b/libstdc++-v3/testsuite/19_diagnostics/runtime_error/constexpr.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++26 } }
+// { dg-require-effective-target cxx11_abi }
 
 #include <string>
 #include <stdexcept>
diff --git a/libstdc++-v3/testsuite/20_util/expected/version.cc b/libstdc++-v3/testsuite/20_util/expected/version.cc
@@ -15,7 +15,7 @@
 # error "Feature-test macro for freestanding expected has wrong value in <version>"
 #endif
 
-#if __cplusplus > 202302L
+#if __cplusplus > 202302L && _GLIBCXX_USE_CXX11_ABI
 # ifndef __cpp_lib_constexpr_exceptions
 #  error "Feature test macro for constexpr_exceptions is missing in <version>"
 # elif __cpp_lib_constexpr_exceptions < 202502L
@@ -40,7 +40,7 @@
 # error "Feature-test macro for freestanding expected has wrong value in <expected>"
 #endif
 
-#if __cplusplus > 202302L
+#if __cplusplus > 202302L && _GLIBCXX_USE_CXX11_ABI
 # ifndef __cpp_lib_constexpr_exceptions
 #  error "Feature test macro for constexpr_exceptions is missing in <expected>"
 # elif __cpp_lib_constexpr_exceptions < 202502L
diff --git a/libstdc++-v3/testsuite/20_util/optional/version.cc b/libstdc++-v3/testsuite/20_util/optional/version.cc
@@ -30,11 +30,13 @@
 #  error "Feature test macro for optional range support has wrong value for C++26 in <version>"
 # endif
 
+# if _GLIBCXX_USE_CXX11_ABI
 # ifndef __cpp_lib_constexpr_exceptions
 #  error "Feature test macro for constexpr_exceptions is missing in <version>"
 # elif __cpp_lib_constexpr_exceptions < 202502L
 #  error "Feature test macro for constexpr_exceptions has wrong value in <version>"
 # endif
+# endif
 #endif
 
 #undef __cpp_lib_optional
@@ -59,9 +61,11 @@
 #  error "Feature test macro for optional range support has wrong value for C++26 in <optional>"
 # endif
 
+# if _GLIBCXX_USE_CXX11_ABI
 # ifndef __cpp_lib_constexpr_exceptions
 #  error "Feature test macro for constexpr_exceptions is missing in <optional>"
 # elif __cpp_lib_constexpr_exceptions < 202502L
 #  error "Feature test macro for constexpr_exceptions has wrong value in <optional>"
 # endif
+# endif
 #endif
diff --git a/libstdc++-v3/testsuite/20_util/variant/version.cc b/libstdc++-v3/testsuite/20_util/variant/version.cc
@@ -19,7 +19,7 @@
 #endif
 #endif
 
-#if __cplusplus > 202302L
+#if __cplusplus > 202302L && _GLIBCXX_USE_CXX11_ABI
 #ifndef __cpp_lib_constexpr_exceptions
 # error "Feature test macro for constexpr_exceptions is missing in <version>"
 #elif __cpp_lib_constexpr_exceptions < 202502L
@@ -40,7 +40,7 @@
 #endif
 #endif
 
-#if __cplusplus > 202302L
+#if __cplusplus > 202302L && _GLIBCXX_USE_CXX11_ABI
 #ifndef __cpp_lib_constexpr_exceptions
 # error "Feature test macro for constexpr_exceptions is missing in <variant>"
 #elif __cpp_lib_constexpr_exceptions < 202502L

Original file line number	Diff line number	Diff line change
`@@ -78,7 +78,9 @@ constexpr bool test01(bool x)`
`78`	`78`	`return true;`
`79`	`79`	`}`
`80`	`80`
	`81`	`+#if _GLIBCXX_USE_CXX11_ABI`
`81`	`82`	`static_assert(test01(false));`
	`83`	`+#endif`
`82`	`84`
`83`	`85`	`int main()`
`84`	`86`	`{`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`// { dg-do compile { target c++26 } }`
	`2`	`+// { dg-require-effective-target cxx11_abi }`
`2`	`3`
`3`	`4`	`#include <string>`
`4`	`5`	`#include <stdexcept>`