Re: [PATCH v2 0/3] detect-compiler: clang updates
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Aug 7, 2021, 02:02 UTC
- Message-ID
- <87bl6aypke.fsf@evledraar.gmail.com>
- In-Reply-To
- <20210806205235.988761-1-gitster@pobox.com>
On Fri, Aug 06 2021, Junio C Hamano wrote:
Show 14 quoted lines
> So here is a mini-series that summarizes what has been suggested so > far on the topic. > > Carlo Marcelo Arenas Belón (1): > build: update detect-compiler for newer Xcode version > > Jeff King (1): > build: clang version may not be followed by extra words > > Junio C Hamano (1): > build: catch clang that identifies itself as "$VENDOR clang" > > detect-compiler | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-)
Perhaps I've missed some obvious reason not to do this, but why are we parsing the --version output of two modern compilers, as opposed to just asking them what type/version they are via their usual macro facilities? I.e. something like the below:
diff --git a/detect-compiler b/detect-compiler index 70b754481c8..37908ac9ea8 100755 --- a/detect-compiler +++ b/detect-compiler @@ -5,19 +5,47 @@ CC="$*" -# we get something like (this is at least true for gcc and clang) +#!/bin/sh # -# FreeBSD clang version 3.4.1 (tags/RELEASE...) -get_version_line() { - $CC -v 2>&1 | grep ' version ' -} +# Probe the compiler for vintage, version, etc. This is used for setting +# optional make knobs under the DEVELOPER knob. + +CC="$*" + +v=$($CC -E - <<-EOF 2>&1 | grep -e '=') +GNUC=__GNUC__ +GNUC_MINOR=__GNUC_MINOR__ +GNUC_PATCHLEVEL=__GNUC_PATCHLEVEL__ +clang=__clang__ +clang_major=__clang_major__ +clang_minor=__clang_minor__ +clang_patchlevel=__clang_patchlevel__ +EOF +eval "$v" get_family() { - get_version_line | sed 's/^\(.*\) version [0-9][^ ]* .*/\1/' + # Clang also sets the GNUC macros, but GCC does not set + # clang's. + if test "$clang" != "__clang__" + then + echo clang + elif test "$GNUC" != "__GNUC__" + then + echo gcc + else + echo unknown + fi } get_version() { - get_version_line | sed 's/^.* version \([0-9][^ ]*\) .*/\1/' + case "$(get_family)" in + clang) + echo "$clang_major.$clang_minor.$clang_patchlevel" + ;; + gcc) + echo "$GNUC.$GNUC_MINOR.$GNUC_PATCHLEVEL" + ;; + esac } print_flags() { @@ -41,12 +69,6 @@ gcc) clang) print_flags clang ;; -"FreeBSD clang") - print_flags clang - ;; -"Apple LLVM") - print_flags clang - ;; *) : unknown compiler family ;;