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- #!/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, $(cc-option, ...) is evaluated as 'y'.
- #
- # This scripts caters to more checks; handle --version and pre-process __GNUC__
- # etc. to pretend to be GCC, and also do right things to satisfy some scripts.
- # Check if the first parameter appears in the rest. Succeeds if found.
- # This helper is useful if a particular option was passed to this script.
- # Typically used like this:
- # arg_contain <word-you-are-searching-for> "$@"
- 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 "$@" && arg_contain -mlittle-endian "$@" &&
- arg_contain -mprofile-kernel "$@"; then
- if ! test -t 0 && ! grep -q notrace; then
- echo "_mcount"
- fi
- exit 0
- fi
- fi
- # To set GCC_PLUGINS
- if arg_contain -print-file-name=plugin "$@"; 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
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