1#!/bin/sh 2# SPDX-License-Identifier: GPL-2.0-only 3# 4# Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG 5# options your compiler does not support. This works well if you configure and 6# build the kernel on the same host machine. 7# 8# It is inconvenient if you prepare the .config that is carried to a different 9# build environment (typically this happens when you package the kernel for 10# distros) because using a different compiler potentially produces different 11# CONFIG options than the real build environment. So, you probably want to make 12# as many options visible as possible. In other words, you need to create a 13# super-set of CONFIG options that cover any build environment. If some of the 14# CONFIG options turned out to be unsupported on the build machine, they are 15# automatically disabled by the nature of Kconfig. 16# 17# However, it is not feasible to get a full-featured compiler for every arch. 18# Hence these dummy toolchains to make all compiler tests pass. 19# 20# Usage: 21# 22# From the top directory of the source tree, run 23# 24# $ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig 25# 26# Most of compiler features are tested by cc-option, which simply checks the 27# exit code of $(CC). This script does nothing and just exits with 0 in most 28# cases. So, $(cc-option, ...) is evaluated as 'y'. 29# 30# This scripts caters to more checks; handle --version and pre-process __GNUC__ 31# etc. to pretend to be GCC, and also do right things to satisfy some scripts. 32 33# Check if the first parameter appears in the rest. Succeeds if found. 34# This helper is useful if a particular option was passed to this script. 35# Typically used like this: 36# arg_contain <word-you-are-searching-for> "$@" 37arg_contain () 38{ 39 search="$1" 40 shift 41 42 while [ $# -gt 0 ] 43 do 44 if [ "$search" = "$1" ]; then 45 return 0 46 fi 47 shift 48 done 49 50 return 1 51} 52 53# To set CONFIG_CC_IS_GCC=y 54if arg_contain --version "$@"; then 55 echo "gcc (scripts/dummy-tools/gcc)" 56 exit 0 57fi 58 59if arg_contain -E "$@"; then 60 # For scripts/gcc-version.sh; This emulates GCC 20.0.0 61 if arg_contain - "$@"; then 62 sed 's/^__GNUC__$/20/; s/^__GNUC_MINOR__$/0/; s/^__GNUC_PATCHLEVEL__$/0/' 63 exit 0 64 else 65 echo "no input files" >&2 66 exit 1 67 fi 68fi 69 70if arg_contain -S "$@"; then 71 # For scripts/gcc-x86-*-has-stack-protector.sh 72 if arg_contain -fstack-protector "$@"; then 73 echo "%gs" 74 exit 0 75 fi 76fi 77 78# For scripts/gcc-plugin.sh 79if arg_contain -print-file-name=plugin "$@"; then 80 plugin_dir=$(mktemp -d) 81 82 sed -n 's/.*#include "\(.*\)"/\1/p' $(dirname $0)/../gcc-plugins/gcc-common.h | 83 while read header 84 do 85 mkdir -p $plugin_dir/include/$(dirname $header) 86 touch $plugin_dir/include/$header 87 done 88 89 echo $plugin_dir 90 exit 0 91fi 92