[libcxx-commits] [libcxx] [libc++][hardening] Always enable all checks during constant evaluation (PR #107713)

[Mital Ashok via libcxx-commits]

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@@ -17,23 +17,38 @@
 #  pragma GCC system_header
 #endif
 
+#ifdef _LIBCPP_COMPILER_CLANG_BASED
+// TODO: use `_LIBCPP_DIAGNOSTIC_*` macros after #107715 is fixed in all supported clang compilers
+#  define _LIBCPP_ASSERT_IS_CONSTANT_EVALUATED                                                                         \
+    (_Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wconstant-evaluated\"")                     \
+         __builtin_is_constant_evaluated() _Pragma("clang diagnostic pop"))
+#else
+#  define _LIBCPP_ASSERT_IS_CONSTANT_EVALUATED (__builtin_is_constant_evaluated())
+#endif
+
 #define _LIBCPP_ASSERT(expression, message)                                                                            \
-  (__builtin_expect(static_cast<bool>(expression), 1)                                                                  \
-       ? (void)0                                                                                                       \
+  (__builtin_expect(static_cast<bool>(expression), 1) ? (void)0                                                        \
+   : _LIBCPP_ASSERT_IS_CONSTANT_EVALUATED                                                                              \
+       ? __builtin_unreachable()                                                                                       \
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MitalAshok wrote:

The original idea was the diagnostic would be consistent, but on second thoughts that isn't worth the extra complexity. I'll revert this.

https://github.com/llvm/llvm-project/pull/107713