[clang] [CUDA][HIP] improve error message for missing cmath (PR #122155)

[Yaxun Liu via cfe-commits]

https://github.com/yxsamliu created https://github.com/llvm/llvm-project/pull/122155

One common error seen in CUDA/HIP compilation is:

fatal error: 'cmath' file not found

which is due to inproper installation of standard C++ libraries.

Since it happens with #include_next, users may feel confusing which cmath is not found and how to fix it.

Add an error directive to help users resolve this issue.

>From cf2586ab3a6afde64b4e9eeb1016a62e28c81cce Mon Sep 17 00:00:00 2001
From: "Yaxun (Sam) Liu" <yaxun.liu at amd.com>
Date: Wed, 8 Jan 2025 13:57:50 -0500
Subject: [PATCH] [CUDA][HIP] improve error message for missing cmath

One common error seen in CUDA/HIP compilation is:

fatal error: 'cmath' file not found

which is due to inproper installation of standard C++ libraries.

Since it happens with #include_next, users may feel confusing
which cmath is not found and how to fix it.

Add an error directive to help users resolve this issue.
---
 clang/lib/Headers/cuda_wrappers/cmath | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/clang/lib/Headers/cuda_wrappers/cmath b/clang/lib/Headers/cuda_wrappers/cmath
index 45f89beec9b4df..7deca678bf252e 100644
--- a/clang/lib/Headers/cuda_wrappers/cmath
+++ b/clang/lib/Headers/cuda_wrappers/cmath
@@ -24,7 +24,11 @@
 #ifndef __CLANG_CUDA_WRAPPERS_CMATH
 #define __CLANG_CUDA_WRAPPERS_CMATH
 
+#if __has_include_next(<cmath>)
 #include_next <cmath>
+#else
+#error "Could not find standard C++ header 'cmath'. Add -v to your compilation command to check the include paths being searched. You may need to install the appropriate standard C++ library package corresponding to the search path."
+#endif
 
 #if defined(_LIBCPP_STD_VER)