fn verify_compiler_support()

in aws-lc-fips-sys/builder/cmake_builder.rs [273:321]

• 46 lines of code
• 13 McCabe index (conditional complexity)

    fn verify_compiler_support(compiler: &cc::Tool) -> Option<bool> {
        let compiler_path = compiler.path();

        if compiler.is_like_gnu() || compiler.is_like_clang() {
            if let TestCommandResult {
                stderr: _,
                stdout,
                executed: true,
                status: true,
            } = execute_command(compiler_path.as_os_str(), &["--version".as_ref()])
            {
                if let Some(first_line) = stdout.lines().nth(0) {
                    if let Some((major, minor, patch)) = parse_version(first_line) {
                        // We don't force a build failure, but we generate a clear message.
                        if compiler.is_like_gnu() {
                            emit_warning(&format!("GCC v{major}.{minor}.{patch} detected."));
                            if major > 13 {
                                // TODO: Update when FIPS GCC 14 build is fixed
                                emit_warning("WARNING: FIPS build is known to fail on GCC >= 14. See: https://github.com/aws/aws-lc-rs/issues/569");
                                emit_warning("Consider specifying a different compiler in your environment by setting `CC` or: `export AWS_LC_FIPS_SYS_CC=clang`");
                                return Some(false);
                            }
                        }
                        if compiler.is_like_clang() {
                            // AWS-LC-FIPS 2.0 was unable to compile with Clang 19
                            emit_warning(&format!("Clang v{major}.{minor}.{patch} detected."));
                        }
                        return Some(true);
                    }
                }
            }
        } else if compiler.is_like_msvc() {
            if let TestCommandResult {
                stderr,
                stdout: _,
                executed: true,
                status: true,
            } = execute_command(compiler_path.as_os_str(), &["/help".as_ref()])
            {
                if let Some(first_line) = stderr.lines().nth(0) {
                    if let Some((major, minor, patch)) = parse_version(first_line) {
                        emit_warning(&format!("MSVC v{major}.{minor}.{patch} detected."));
                        return Some(true);
                    }
                }
            }
        }
        None
    }