[clang] [CUDA][HIP] Add a __device__ version of std::__glibcxx_assert_fail() (PR #136133)

Artem Belevich via cfe-commits cfe-commits at lists.llvm.org
Thu Apr 17 12:02:04 PDT 2025


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@@ -0,0 +1,35 @@
+// libstdc++ uses the non-constexpr function std::__glibcxx_assert_fail()
+// to trigger compilation errors when the __glibcxx_assert(cond) macro
+// is used in a constexpr context.
+// Compilation fails when using code from the libstdc++ (such as std::array) on
+// device code, since these assertions invoke a non-constexpr host function from
+// device code.
+//
+// To work around this issue, we declare our own device version of the function
+
+#ifndef __CLANG_CUDA_WRAPPERS_BITS_CPP_CONFIG
+#define __CLANG_CUDA_WRAPPERS_BITS_CPP_CONFIG
+
+#include_next <bits/c++config.h>
+
+#ifdef _LIBCPP_BEGIN_NAMESPACE_STD
+_LIBCPP_BEGIN_NAMESPACE_STD
+#else
+namespace std {
+#ifdef _GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+#endif
+#endif
+__device__
+    __attribute__((__always_inline__, __visibility__("default"))) inline void
+    __glibcxx_assert_fail() {}
----------------
Artem-B wrote:

Presumably we *do* want to fail here. We should at least call __builtin_abort() or something. 

Also, __glibcxx_assert_fail() appears to have overloads with multiple parameters, too: 

https://github.com/gcc-mirror/gcc/blob/4cff0434e8bf6683988482a7e47f8459c06f2c05/libstdc%2B%2B-v3/src/c%2B%2B11/assert_fail.cc#L33

It looks like it's vestion-dependent, and we may need to provide both variants, otherwise the issue will still be there for other libstdc++ versions. 


https://github.com/llvm/llvm-project/pull/136133


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