linux-yocto/scripts/dummy-tools/gcc

#!/bin/sh

SPDX-License-Identifier: GPL-2.0-only

Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG

options your compiler does not support. This works well if you configure and

build the kernel on the same host machine.

It is inconvenient if you prepare the .config that is carried to a different

build environment (typically this happens when you package the kernel for

distros) because using a different compiler potentially produces different

CONFIG options than the real build environment. So, you probably want to make

as many options visible as possible. In other words, you need to create a

super-set of CONFIG options that cover any build environment. If some of the

CONFIG options turned out to be unsupported on the build machine, they are

automatically disabled by the nature of Kconfig.

However, it is not feasible to get a full-featured compiler for every arch.

Hence these dummy toolchains to make all compiler tests pass.

Usage:

From the top directory of the source tree, run

$ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig

Most of compiler features are tested by cc-option, which simply checks the

exit code of $(CC). This script does nothing and just exits with 0 in most

cases. So, $(cc-option, ...) is evaluated as 'y'.

This scripts caters to more checks; handle --version and pre-process GNUC

etc. to pretend to be GCC, and also do right things to satisfy some scripts.

Check if the first parameter appears in the rest. Succeeds if found.

This helper is useful if a particular option was passed to this script.

Typically used like this:

arg_contain "$@"

arg_contain () { search="$1" shift

while [ $# -gt 0 ]
do
	if [ "$search" = "$1" ]; then
		return 0
	fi
	shift
done

return 1

}

To set CONFIG_CC_IS_GCC=y

if arg_contain --version "$@"; then echo "gcc (scripts/dummy-tools/gcc)" exit 0 fi

if arg_contain -E "$@"; then # For scripts/cc-version.sh; This emulates GCC 20.0.0 if arg_contain - "$@"; then sed -n '/^GCC/{s/GNUC/20/; s/GNUC_MINOR/0/; s/GNUC_PATCHLEVEL/0/; p;}; s/LONG_DOUBLE_128/1/ p' exit 0 else echo "no input files" >&2 exit 1 fi fi

To set CONFIG_AS_IS_GNU

if arg_contain -Wa,--version "$@"; then echo "GNU assembler (scripts/dummy-tools) 2.50" exit 0 fi

if arg_contain -S "$@"; then # For scripts/gcc-x86-*-has-stack-protector.sh if arg_contain -fstack-protector "$@"; then if arg_contain -mstack-protector-guard-reg=fs "$@"; then echo "%fs" else echo "%gs" fi exit 0 fi

# For arch/powerpc/tools/gcc-check-mprofile-kernel.sh
if arg_contain -m64 "$@" && arg_contain -mprofile-kernel "$@"; then
	if ! test -t 0 && ! grep -q notrace; then
		echo "_mcount"
	fi
	exit 0
fi

# For arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
if arg_contain -m64 "$@" && arg_contain -fpatchable-function-entry=2 "$@"; then
	echo "func:"
	echo ".section __patchable_function_entries"
	echo ".localentry"
	echo "  nop"
	echo "  nop"
	exit 0
fi

fi

To set GCC_PLUGINS

if arg_contain -print-file-name=plugin "$@"; then # Use $0 to find the in-tree dummy directory echo "$(dirname "$(readlink -f "$0")")/dummy-plugin-dir" exit 0 fi

inverted return value

if arg_contain -D__SIZEOF_INT128__=0 "$@"; then exit 1 fi