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List:       gentoo-dev
Subject:    [gentoo-dev] Re: [PATCH] flag-o-matic.eclass: add LDFLAGS testing against linker
From:       Sergei Trofimovich <slyfox () gentoo ! org>
Date:       2019-12-25 10:45:38
Message-ID: 20191225104538.6f2b536c () sf
[Download RAW message or body]

On Mon, 23 Dec 2019 11:50:43 +0000
Sergei Trofimovich <slyfox@gentoo.org> wrote:

> Before the change we tested only compiler driver (gcc flag parser)
> for LDFLAGS.
> 
> This does not cover cases when we would really like to filter out
> unsupported linker flags like -Wl,--hash-style=gnu passed to non-ELF
> targets.
> 
> The change adds test-flag-CCLD() helper to perform all of assembly,
> compilation and linking steps. Helper is used to filter LDFLAGS variable
> in strip-unsupported-flags().
> 
> Closes: https://bugs.gentoo.org/333763
> Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
> ---

Pushed as:
    https://gitweb.gentoo.org/repo/gentoo.git/commit/eclass?id=28d6437fc7009002f98f28e8900e994109927726


> eclass/flag-o-matic.eclass   | 72 +++++++++++++++++++++++++++++-------
> eclass/tests/flag-o-matic.sh |  2 +-
> 2 files changed, 59 insertions(+), 15 deletions(-)
> 
> diff --git a/eclass/flag-o-matic.eclass b/eclass/flag-o-matic.eclass
> index f882b09d621..0aec22c83f2 100644
> --- a/eclass/flag-o-matic.eclass
> +++ b/eclass/flag-o-matic.eclass
> @@ -441,29 +441,63 @@ test-flag-PROG() {
> 	# 'type' needs a binary name
> 	type -p ${comp[0]} >/dev/null || return 1
> 
> +	# Set up test file.
> +	local in_src in_ext cmdline_extra=()
> +	case "${lang}" in
> +		# compiler/assembler only
> +		c)
> +			in_ext='.c'
> +			in_src='int main(void) { return 0; }'
> +			cmdline_extra+=(-xc -c)
> +			;;
> +		c++)
> +			in_ext='.cc'
> +			in_src='int main(void) { return 0; }'
> +			cmdline_extra+=(-xc++ -c)
> +			;;
> +		f77)
> +			in_ext='.f'
> +			# fixed source form
> +			in_src='      end'
> +			cmdline_extra+=(-xf77 -c)
> +			;;
> +		f95)
> +			in_ext='.f90'
> +			in_src='end'
> +			cmdline_extra+=(-xf95 -c)
> +			;;
> +
> +		# C compiler/assembler/linker
> +		c+ld)
> +			in_ext='.c'
> +			in_src='int main(void) { return 0; }'
> +			cmdline_extra+=(-xc)
> +			;;
> +	esac
> +	local test_in=${T}/test-flag-${comp}.${lang}
> +	local test_out=${T}/test-flag-${comp}.exe
> +
> +	printf "%s\n" "${in_src}" > "${test_in}" || return 1
> +
> 	local cmdline=(
> 		"${comp[@]}"
> 		# Clang will warn about unknown gcc flags but exit 0.
> 		# Need -Werror to force it to exit non-zero.
> 		-Werror
> -		# Use -c so we can test the assembler as well.
> -		-c -o /dev/null
> +		"$@"
> +		# -x<lang> options need to go before first source file
> +		"${cmdline_extra[@]}"
> +
> +		"${test_in}" -o "${test_out}"
> 	)
> -	if "${cmdline[@]}" -x${lang} - </dev/null &>/dev/null ; then
> -		cmdline+=( "$@" -x${lang} - )
> -	else
> -		# XXX: what's the purpose of this? does it even work with
> -		# any compiler?
> -		cmdline+=( "$@" -c -o /dev/null /dev/null )
> -	fi
> 
> -	if ! "${cmdline[@]}" </dev/null &>/dev/null; then
> +	if ! "${cmdline[@]}" &>/dev/null; then
> 		# -Werror makes clang bail out on unused arguments as well;
> 		# try to add -Qunused-arguments to work-around that
> 		# other compilers don't support it but then, it's failure like
> 		# any other
> 		cmdline+=( -Qunused-arguments )
> -		"${cmdline[@]}" </dev/null &>/dev/null
> +		"${cmdline[@]}" &>/dev/null
> 	fi
> }
> 
> @@ -491,6 +525,12 @@ test-flag-F77() { test-flag-PROG "F77" f77 "$@"; }
> # Returns shell true if <flag> is supported by the Fortran 90 compiler, else \
> returns shell false. test-flag-FC() { test-flag-PROG "FC" f95 "$@"; }
> 
> +# @FUNCTION: test-flag-CCLD
> +# @USAGE: <flag>
> +# @DESCRIPTION:
> +# Returns shell true if <flag> is supported by the C compiler and linker, else \
> returns shell false. +test-flag-CCLD() { test-flag-PROG "CC" c+ld "$@"; }
> +
> test-flags-PROG() {
> 	local comp=$1
> 	local flags=()
> @@ -548,6 +588,12 @@ test-flags-F77() { test-flags-PROG "F77" "$@"; }
> # Returns shell true if <flags> are supported by the Fortran 90 compiler, else \
> returns shell false. test-flags-FC() { test-flags-PROG "FC" "$@"; }
> 
> +# @FUNCTION: test-flags-CCLD
> +# @USAGE: <flags>
> +# @DESCRIPTION:
> +# Returns shell true if <flags> are supported by the C compiler and default \
> linker, else returns shell false. +test-flags-CCLD() { test-flags-PROG "CCLD" "$@"; \
> } +
> # @FUNCTION: test-flags
> # @USAGE: <flags>
> # @DESCRIPTION:
> @@ -576,9 +622,7 @@ strip-unsupported-flags() {
> 	export CXXFLAGS=$(test-flags-CXX ${CXXFLAGS})
> 	export FFLAGS=$(test-flags-F77 ${FFLAGS})
> 	export FCFLAGS=$(test-flags-FC ${FCFLAGS})
> -	# note: this does not verify the linker flags but it is enough
> -	# to strip invalid C flags which are much more likely, #621274
> -	export LDFLAGS=$(test-flags-CC ${LDFLAGS})
> +	export LDFLAGS=$(test-flags-CCLD ${LDFLAGS})
> }
> 
> # @FUNCTION: get-flag
> diff --git a/eclass/tests/flag-o-matic.sh b/eclass/tests/flag-o-matic.sh
> index 7c078499d70..90eaf3a6ffb 100755
> --- a/eclass/tests/flag-o-matic.sh
> +++ b/eclass/tests/flag-o-matic.sh
> @@ -8,7 +8,7 @@ inherit flag-o-matic
> 
> CFLAGS="-a -b -c=1 --param l1-cache-size=32"
> CXXFLAGS="-x -y -z=2"
> -LDFLAGS="-l -m -n=3"
> +LDFLAGS="-l -m -n=3 -Wl,--remove-me"
> ftend() {
> 	local ret=$?
> 	local msg="Failed; flags are:"
> -- 
> 2.24.1
> 


-- 

  Sergei


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