1 # Copyright 1999-2020 Gentoo Authors
2 # Distributed under the terms of the GNU General Public License v2
4 # @ECLASS: flag-o-matic.eclass
7 # @BLURB: common functions to manipulate and query toolchain flags
9 # This eclass contains a suite of functions to help developers sanely
10 # and safely manage toolchain flags in their builds.
12 if [[ -z ${_FLAG_O_MATIC_ECLASS} ]]; then
13 _FLAG_O_MATIC_ECLASS=1
15 inherit eutils toolchain-funcs multilib
17 # Return all the flag variables that our high level funcs operate on.
19 echo {ADA,C,CPP,CXX,CCAS,F,FC,LD}FLAGS
22 # {C,CPP,CXX,CCAS,F,FC,LD}FLAGS that we allow in strip-flags
23 # Note: shell globs and character lists are allowed
24 setup-allowed-flags() {
26 -pipe -O '-O[12sg]' -mcpu -march -mtune
27 '-fstack-protector*' '-fsanitize*' '-fstack-check*' -fno-stack-check
28 -fbounds-check -fbounds-checking -fno-strict-overflow
29 -fno-PIE -fno-pie -nopie -no-pie -fno-unit-at-a-time
30 -g '-g[0-9]' -ggdb '-ggdb[0-9]' '-gdwarf-*' gstabs -gstabs+ -gz
31 -fno-ident -fpermissive -frecord-gcc-switches
32 '-fdiagnostics*' '-fplugin*'
35 # CPPFLAGS and LDFLAGS
42 # allow a bunch of flags that negate features / control ABI
44 '-fno-stack-protector*' '-fabi-version=*'
45 -fno-strict-aliasing -fno-bounds-check -fno-bounds-checking -fstrict-overflow
46 -fno-omit-frame-pointer '-fno-builtin*'
49 -mregparm -mno-app-regs -mapp-regs -mno-mmx -mno-sse
50 -mno-sse2 -mno-sse3 -mno-ssse3 -mno-sse4 -mno-sse4.1 -mno-sse4.2
51 -mno-avx -mno-aes -mno-pclmul -mno-sse4a -mno-3dnow -mno-popcnt
52 -mno-abm -mips1 -mips2 -mips3 -mips4 -mips32 -mips64 -mips16 -mplt
53 -msoft-float -mno-soft-float -mhard-float -mno-hard-float -mfpu
54 -mieee -mieee-with-inexact -mschedule -mfloat-gprs -mspe -mno-spe
55 -mtls-direct-seg-refs -mno-tls-direct-seg-refs -mflat -mno-flat
56 -mno-faster-structs -mfaster-structs -m32 -m64 -mx32 -mabi
57 -mlittle-endian -mbig-endian -EL -EB -fPIC -mlive-g0 -mcmodel
58 -mstack-bias -mno-stack-bias -msecure-plt '-m*-toc' -mfloat-abi
59 -mfix-r4000 -mno-fix-r4000 -mfix-r4400 -mno-fix-r4400
60 -mfix-rm7000 -mno-fix-rm7000 -mfix-r10000 -mno-fix-r10000
61 -mr10k-cache-barrier -mthumb -marm
64 -mno-fma4 -mno-movbe -mno-xop -mno-lwp
66 -mno-fsgsbase -mno-rdrnd -mno-f16c -mno-bmi -mno-tbm
68 -mno-avx2 -mno-bmi2 -mno-fma -mno-lzcnt
70 -mno-fxsr -mno-hle -mno-rtm -mno-xsave -mno-xsaveopt
72 -mno-avx512cd -mno-avx512er -mno-avx512f -mno-avx512pf -mno-sha
75 # Allow some safe individual flags. Should come along with the bug reference.
77 # Allow explicit stack realignment to run non-conformant
78 # binaries: bug #677852
83 # inverted filters for hardened compiler. This is trying to unpick
84 # the hardened compiler defaults.
89 # Ideally we should only concern ourselves with PIE flags,
90 # not -fPIC or -fpic, but too many places filter -fPIC without
91 # thinking about -fPIE.
92 -fPIC|-fpic|-fPIE|-fpie|-Wl,pie|-pie)
93 gcc-specs-pie || continue
94 if ! is-flagq -nopie && ! is-flagq -no-pie ; then
95 # Support older Gentoo form first (-nopie) before falling
96 # back to the official gcc-6+ form (-no-pie).
97 if test-flags -nopie >/dev/null ; then
105 gcc-specs-ssp || continue
106 is-flagq -fno-stack-protector || append-flags $(test-flags -fno-stack-protector);;
107 -fstack-protector-all)
108 gcc-specs-ssp-to-all || continue
109 is-flagq -fno-stack-protector-all || append-flags $(test-flags -fno-stack-protector-all);;
110 -fno-strict-overflow)
111 gcc-specs-nostrict || continue
112 is-flagq -fstrict-overflow || append-flags $(test-flags -fstrict-overflow);;
117 # Remove occurrences of strings from variable given in $1
118 # Strings removed are matched as globs, so for example
119 # '-O*' would remove -O1, -O2 etc.
121 local f x var=$1 new=()
124 for f in ${!var} ; do
126 # Note this should work with globs like -O*
127 [[ ${f} == ${x} ]] && continue 2
131 export ${var}="${new[*]}"
134 # @FUNCTION: filter-flags
137 # Remove particular <flags> from {C,CPP,CXX,CCAS,F,FC,LD}FLAGS. Accepts shell globs.
139 _filter-hardened "$@"
141 for v in $(all-flag-vars) ; do
142 _filter-var ${v} "$@"
147 # @FUNCTION: filter-lfs-flags
149 # Remove flags that enable Large File Support.
151 [[ $# -ne 0 ]] && die "filter-lfs-flags takes no arguments"
152 # http://www.gnu.org/s/libc/manual/html_node/Feature-Test-Macros.html
153 # _LARGEFILE_SOURCE: enable support for new LFS funcs (ftello/etc...)
154 # _LARGEFILE64_SOURCE: enable support for 64bit variants (off64_t/fseeko64/etc...)
155 # _FILE_OFFSET_BITS: default to 64bit variants (off_t is defined as off64_t)
156 filter-flags -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
159 # @FUNCTION: filter-ldflags
162 # Remove particular <flags> from LDFLAGS. Accepts shell globs.
164 _filter-var LDFLAGS "$@"
168 # @FUNCTION: append-cppflags
171 # Add extra <flags> to the current CPPFLAGS.
173 [[ $# -eq 0 ]] && return 0
174 export CPPFLAGS+=" $*"
178 # @FUNCTION: append-cflags
181 # Add extra <flags> to the current CFLAGS. If a flag might not be supported
182 # with different compilers (or versions), then use test-flags-CC like so:
184 # append-cflags $(test-flags-CC -funky-flag)
187 [[ $# -eq 0 ]] && return 0
188 # Do not do automatic flag testing ourselves. #417047
193 # @FUNCTION: append-cxxflags
196 # Add extra <flags> to the current CXXFLAGS. If a flag might not be supported
197 # with different compilers (or versions), then use test-flags-CXX like so:
199 # append-cxxflags $(test-flags-CXX -funky-flag)
202 [[ $# -eq 0 ]] && return 0
203 # Do not do automatic flag testing ourselves. #417047
204 export CXXFLAGS+=" $*"
208 # @FUNCTION: append-fflags
211 # Add extra <flags> to the current {F,FC}FLAGS. If a flag might not be supported
212 # with different compilers (or versions), then use test-flags-F77 like so:
214 # append-fflags $(test-flags-F77 -funky-flag)
217 [[ $# -eq 0 ]] && return 0
218 # Do not do automatic flag testing ourselves. #417047
220 export FCFLAGS+=" $*"
224 # @FUNCTION: append-lfs-flags
226 # Add flags that enable Large File Support.
228 [[ $# -ne 0 ]] && die "append-lfs-flags takes no arguments"
229 # see comments in filter-lfs-flags func for meaning of these
230 append-cppflags -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
233 # @FUNCTION: append-ldflags
236 # Add extra <flags> to the current LDFLAGS.
238 [[ $# -eq 0 ]] && return 0
241 [[ ${flag} == -l* ]] && \
242 eqawarn "Appending a library link instruction (${flag}); libraries to link to should not be passed through LDFLAGS"
245 export LDFLAGS="${LDFLAGS} $*"
249 # @FUNCTION: append-flags
252 # Add extra <flags> to your current {C,CXX,F,FC}FLAGS.
254 [[ $# -eq 0 ]] && return 0
256 *' '-[DIU]*) eqawarn 'please use append-cppflags for preprocessor flags' ;;
258 *' '-Wl,*) eqawarn 'please use append-ldflags for linker flags' ;;
266 # @FUNCTION: replace-flags
267 # @USAGE: <old> <new>
269 # Replace the <old> flag with <new>. Accepts shell globs for <old>.
271 [[ $# != 2 ]] && die "Usage: replace-flags <old flag> <new flag>"
274 for var in $(all-flag-vars) ; do
275 # Looping over the flags instead of using a global
276 # substitution ensures that we're working with flag atoms.
277 # Otherwise globs like -O* have the potential to wipe out the
280 for f in ${!var} ; do
281 # Note this should work with globs like -O*
282 [[ ${f} == ${1} ]] && f=${2}
285 export ${var}="${new[*]}"
291 # @FUNCTION: replace-cpu-flags
292 # @USAGE: <old> <new>
294 # Replace cpu flags (like -march/-mcpu/-mtune) that select the <old> cpu
295 # with flags that select the <new> cpu. Accepts shell globs for <old>.
296 replace-cpu-flags() {
297 local newcpu="$#" ; newcpu="${!newcpu}"
298 while [ $# -gt 1 ] ; do
299 # quote to make sure that no globbing is done (particularly on
300 # ${oldcpu}) prior to calling replace-flags
301 replace-flags "-march=${1}" "-march=${newcpu}"
302 replace-flags "-mcpu=${1}" "-mcpu=${newcpu}"
303 replace-flags "-mtune=${1}" "-mtune=${newcpu}"
311 for x in ${!var} ; do
312 [[ ${x} == $2 ]] && return 0
317 # @FUNCTION: is-flagq
320 # Returns shell true if <flag> is in {C,CXX,F,FC}FLAGS, else returns shell false. Accepts shell globs.
322 [[ -n $2 ]] && die "Usage: is-flag <flag>"
325 for var in $(all-flag-vars) ; do
326 _is_flagq ${var} "$1" && return 0
334 # Echo's "true" if flag is set in {C,CXX,F,FC}FLAGS. Accepts shell globs.
336 is-flagq "$@" && echo true
339 # @FUNCTION: is-ldflagq
342 # Returns shell true if <flag> is in LDFLAGS, else returns shell false. Accepts shell globs.
344 [[ -n $2 ]] && die "Usage: is-ldflag <flag>"
348 # @FUNCTION: is-ldflag
351 # Echo's "true" if flag is set in LDFLAGS. Accepts shell globs.
353 is-ldflagq "$@" && echo true
356 # @FUNCTION: filter-mfpmath
357 # @USAGE: <math types>
359 # Remove specified math types from the fpmath flag. For example, if the user
360 # has -mfpmath=sse,386, running `filter-mfpmath sse` will leave the user with
363 local orig_mfpmath new_math prune_math
365 # save the original -mfpmath flag
366 orig_mfpmath=$(get-flag -mfpmath)
367 # get the value of the current -mfpmath flag
368 new_math=$(get-flag mfpmath)
369 # convert "both" to something we can filter
370 new_math=${new_math/both/387,sse}
371 new_math=" ${new_math//[,+]/ } "
372 # figure out which math values are to be removed
374 for prune_math in "$@" ; do
375 new_math=${new_math/ ${prune_math} / }
377 new_math=$(echo ${new_math})
378 new_math=${new_math// /,}
380 if [[ -z ${new_math} ]] ; then
381 # if we're removing all user specified math values are
382 # slated for removal, then we just filter the flag
383 filter-flags ${orig_mfpmath}
385 # if we only want to filter some of the user specified
386 # math values, then we replace the current flag
387 replace-flags ${orig_mfpmath} -mfpmath=${new_math}
392 # @FUNCTION: strip-flags
394 # Strip *FLAGS of everything except known good/safe flags. This runs over all
395 # flags returned by all_flag_vars().
397 [[ $# -ne 0 ]] && die "strip-flags takes no arguments"
403 set -f # disable pathname expansion
405 for var in $(all-flag-vars) ; do
408 for x in ${!var} ; do
410 for y in "${ALLOWED_FLAGS[@]}" ; do
411 if [[ -z ${flag%%${y}} ]] ; then
418 # In case we filtered out all optimization flags fallback to -O2
419 if _is_flagq ${var} "-O*" && ! _is_flagq new "-O*" ; then
423 if [[ ${!var} != "${new[*]}" ]] ; then
424 einfo "strip-flags: ${var}: changed '${!var}' to '${new[*]}'"
426 export ${var}="${new[*]}"
429 set +f # re-enable pathname expansion
439 if [[ -z ${comp} ]]; then
446 # verify selected compiler exists before using it
447 comp=($(tc-get${comp}))
448 # 'comp' can already contain compiler options.
449 # 'type' needs a binary name
450 if ! type -p ${comp[0]} >/dev/null; then
455 local in_src in_ext cmdline_extra=()
457 # compiler/assembler only
460 in_src='int main(void) { return 0; }'
461 cmdline_extra+=(-xc -c)
465 in_src='int main(void) { return 0; }'
466 cmdline_extra+=(-xc++ -c)
472 cmdline_extra+=(-xf77 -c)
477 cmdline_extra+=(-xf95 -c)
480 # C compiler/assembler/linker
483 in_src='int main(void) { return 0; }'
487 local test_in=${T}/test-flag.${in_ext}
488 local test_out=${T}/test-flag.exe
490 printf "%s\n" "${in_src}" > "${test_in}" || die "Failed to create '${test_in}'"
492 # Currently we rely on warning-free output of a compiler
493 # before the flag to see if a flag prduces any warnings.
494 # This has a few drawbacks:
495 # - if compiler already generates warnings we filter out
496 # every single flag: bug #712488
497 # - if user actually wants to see warnings we just strip
498 # them regardless of warnings type.
500 # We can add more selective detection of no-op flags via
501 # '-Werror=ignored-optimization-argument' and similar error options
502 # similar to what we are doing with '-Qunused-arguments'.
505 # Clang will warn about unknown gcc flags but exit 0.
506 # Need -Werror to force it to exit non-zero.
509 # -x<lang> options need to go before first source file
510 "${cmdline_extra[@]}"
512 "${test_in}" -o "${test_out}"
515 if ! "${cmdline[@]}" &>/dev/null; then
516 # -Werror makes clang bail out on unused arguments as well;
517 # try to add -Qunused-arguments to work-around that
518 # other compilers don't support it but then, it's failure like
520 cmdline+=( -Qunused-arguments )
521 "${cmdline[@]}" &>/dev/null
525 # @FUNCTION: test-flag-CC
528 # Returns shell true if <flag> is supported by the C compiler, else returns shell false.
529 test-flag-CC() { test-flag-PROG "CC" c "$@"; }
531 # @FUNCTION: test-flag-CXX
534 # Returns shell true if <flag> is supported by the C++ compiler, else returns shell false.
535 test-flag-CXX() { test-flag-PROG "CXX" c++ "$@"; }
537 # @FUNCTION: test-flag-F77
540 # Returns shell true if <flag> is supported by the Fortran 77 compiler, else returns shell false.
541 test-flag-F77() { test-flag-PROG "F77" f77 "$@"; }
543 # @FUNCTION: test-flag-FC
546 # Returns shell true if <flag> is supported by the Fortran 90 compiler, else returns shell false.
547 test-flag-FC() { test-flag-PROG "FC" f95 "$@"; }
549 # @FUNCTION: test-flag-CCLD
552 # Returns shell true if <flag> is supported by the C compiler and linker, else returns shell false.
553 test-flag-CCLD() { test-flag-PROG "CC" c+ld "$@"; }
562 [[ -z ${comp} ]] && return 1
566 # '-B /foo': bug # 687198
568 if test-flag-${comp} "$1" "$2"; then
574 if test-flag-${comp} "$1"; then
584 # Just bail if we dont have any flags
585 [[ ${#flags[@]} -gt 0 ]]
588 # @FUNCTION: test-flags-CC
591 # Returns shell true if <flags> are supported by the C compiler, else returns shell false.
592 test-flags-CC() { test-flags-PROG "CC" "$@"; }
594 # @FUNCTION: test-flags-CXX
597 # Returns shell true if <flags> are supported by the C++ compiler, else returns shell false.
598 test-flags-CXX() { test-flags-PROG "CXX" "$@"; }
600 # @FUNCTION: test-flags-F77
603 # Returns shell true if <flags> are supported by the Fortran 77 compiler, else returns shell false.
604 test-flags-F77() { test-flags-PROG "F77" "$@"; }
606 # @FUNCTION: test-flags-FC
609 # Returns shell true if <flags> are supported by the Fortran 90 compiler, else returns shell false.
610 test-flags-FC() { test-flags-PROG "FC" "$@"; }
612 # @FUNCTION: test-flags-CCLD
615 # Returns shell true if <flags> are supported by the C compiler and default linker, else returns shell false.
616 test-flags-CCLD() { test-flags-PROG "CCLD" "$@"; }
618 # @FUNCTION: test-flags
621 # Short-hand that should hopefully work for both C and C++ compiler, but
622 # its really only present due to the append-flags() abomination.
623 test-flags() { test-flags-CC "$@"; }
625 # @FUNCTION: test_version_info
628 # Returns shell true if the current C compiler version matches <version>, else returns shell false.
629 # Accepts shell globs.
630 test_version_info() {
631 if [[ $($(tc-getCC) --version 2>&1) == *$1* ]]; then
638 # @FUNCTION: strip-unsupported-flags
640 # Strip {C,CXX,F,FC}FLAGS of any flags not supported by the active toolchain.
641 strip-unsupported-flags() {
642 [[ $# -ne 0 ]] && die "strip-unsupported-flags takes no arguments"
643 export CFLAGS=$(test-flags-CC ${CFLAGS})
644 export CXXFLAGS=$(test-flags-CXX ${CXXFLAGS})
645 export FFLAGS=$(test-flags-F77 ${FFLAGS})
646 export FCFLAGS=$(test-flags-FC ${FCFLAGS})
647 export LDFLAGS=$(test-flags-CCLD ${LDFLAGS})
650 # @FUNCTION: get-flag
653 # Find and echo the value for a particular flag. Accepts shell globs.
655 [[ $# -ne 1 ]] && die "usage: <flag>"
656 local f var findflag="$1"
658 # this code looks a little flaky but seems to work for
659 # everything we want ...
660 # for example, if CFLAGS="-march=i686":
661 # `get-flag -march` == "-march=i686"
662 # `get-flag march` == "i686"
663 for var in $(all-flag-vars) ; do
664 for f in ${!var} ; do
665 if [ "${f/${findflag}}" != "${f}" ] ; then
666 printf "%s\n" "${f/-${findflag}=}"
674 # @FUNCTION: replace-sparc64-flags
676 # Sets mcpu to v8 and uses the original value as mtune if none specified.
677 replace-sparc64-flags() {
678 [[ $# -ne 0 ]] && die "replace-sparc64-flags takes no arguments"
679 local SPARC64_CPUS="ultrasparc3 ultrasparc v9"
681 if [ "${CFLAGS/mtune}" != "${CFLAGS}" ]; then
682 for x in ${SPARC64_CPUS}; do
683 CFLAGS="${CFLAGS/-mcpu=${x}/-mcpu=v8}"
686 for x in ${SPARC64_CPUS}; do
687 CFLAGS="${CFLAGS/-mcpu=${x}/-mcpu=v8 -mtune=${x}}"
691 if [ "${CXXFLAGS/mtune}" != "${CXXFLAGS}" ]; then
692 for x in ${SPARC64_CPUS}; do
693 CXXFLAGS="${CXXFLAGS/-mcpu=${x}/-mcpu=v8}"
696 for x in ${SPARC64_CPUS}; do
697 CXXFLAGS="${CXXFLAGS/-mcpu=${x}/-mcpu=v8 -mtune=${x}}"
701 export CFLAGS CXXFLAGS
704 # @FUNCTION: append-libs
707 # Add extra <libs> to the current LIBS. All arguments should be prefixed with
708 # either -l or -L. For compatibility, if arguments are not prefixed as
709 # options, they are given a -l prefix automatically.
711 [[ $# -eq 0 ]] && return 0
714 if [[ -z "${flag// }" ]]; then
715 eqawarn "Appending an empty argument to LIBS is invalid! Skipping."
720 export LIBS="${LIBS} ${flag}"
723 eqawarn "Appending non-library to LIBS (${flag}); Other linker flags should be passed via LDFLAGS"
724 export LIBS="${LIBS} ${flag}"
727 export LIBS="${LIBS} -l${flag}"
734 # @FUNCTION: raw-ldflags
737 # Turn C style ldflags (-Wl,-foo) into straight ldflags - the results
738 # are suitable for passing directly to 'ld'; note LDFLAGS is usually passed
739 # to gcc where it needs the '-Wl,'.
741 # If no flags are specified, then default to ${LDFLAGS}.
744 [[ -z ${input} ]] && input=${LDFLAGS}
746 for x in ${input} ; do
750 set -- "$@" ${x//,/ }
752 *) # Assume it's a compiler driver flag, so throw it away #441808
759 # @FUNCTION: no-as-needed
760 # @RETURN: Flag to disable asneeded behavior for use with append-ldflags.
762 [[ $# -ne 0 ]] && die "no-as-needed takes no arguments"
763 case $($(tc-getLD) -v 2>&1 </dev/null) in
765 echo "-Wl,--no-as-needed" ;;