diff --git a/src/Compilation.zig b/src/Compilation.zig index d6157fec82..177c71f4d1 100644 --- a/src/Compilation.zig +++ b/src/Compilation.zig @@ -4457,9 +4457,18 @@ pub fn addCCArgs( if (comp.sanitize_c and !comp.bin_file.options.tsan) { try argv.append("-fsanitize=undefined"); try argv.append("-fsanitize-trap=undefined"); + // It is very common, and well-defined, for a pointer on one side of a C ABI + // to have a different but compatible element type. Examples include: + // `char*` vs `uint8_t*` on a system with 8-bit bytes + // `const char*` vs `char*` + // `char*` vs `unsigned char*` + // Without this flag, Clang would invoke UBSAN when such an extern + // function was called. + try argv.append("-fno-sanitize=function"); } else if (comp.sanitize_c and comp.bin_file.options.tsan) { try argv.append("-fsanitize=undefined,thread"); try argv.append("-fsanitize-trap=undefined"); + try argv.append("-fno-sanitize=function"); } else if (!comp.sanitize_c and comp.bin_file.options.tsan) { try argv.append("-fsanitize=thread"); }