Merge pull request #78930 from compnerd/this-is-your-last-warning

Runtimes: treat linker warnings as errors

Author: compnerd

Runtimes/Core/CMakeLists.txt

@@ -144,6 +144,15 @@ add_compile_options(
   $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions>
   $<$<COMPILE_LANGUAGE:CXX>:-funwind-tables>)
 
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+
 add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-library-level api>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-runtime-compatibility-version none>"