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Date: Tue, 29 Nov 2016 12:33:15 -0200
From: Arnaldo Carvalho de Melo <acme@redhat.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Foley <pefoley2@pefoley.com>,
        LKML <linux-kernel@vger.kernel.org>, wangnan0@huawei.com
Subject: Re: [PATCH v2] Fix objtool with clang
Message-ID: <20161129143314.GC2361@redhat.com>
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Em Tue, Nov 29, 2016 at 03:28:08PM +0100, Jiri Olsa escreveu:
> On Mon, Nov 28, 2016 at 05:40:46PM -0200, Arnaldo Carvalho de Melo wrote:
> 
> SNIP
> 
> >   CC       /tmp/build/perf/builtin-buildid-list.o
> >   LD       /tmp/build/perf/pmu-events/pmu-events-in.o
> >   CC       /tmp/build/perf/arch/x86/util/intel-bts.o
> >   CC       /tmp/build/perf/builtin-buildid-cache.o
> >   CC       /tmp/build/perf/builtin-list.o
> >   LD       /tmp/build/perf/arch/x86/util/libperf-in.o
> >   MKDIR    /tmp/build/perf/arch/x86/tests/
> >   CC       /tmp/build/perf/arch/x86/tests/regs_load.o
> > /tmp/build/perf/.plugin_jbd2.o.cmd:3: *** empty variable name.  Stop.
> > Makefile:192: recipe for target '/tmp/build/perf/plugin_jbd2-in.o' failed
> > make[2]: *** [/tmp/build/perf/plugin_jbd2-in.o] Error 2
> > Makefile.perf:591: recipe for target '/tmp/build/perf/libtraceevent-dynamic-list' failed
> > make[1]: *** [/tmp/build/perf/libtraceevent-dynamic-list] Error 2
> > make[1]: *** Waiting for unfinished jobs....
> >   MKDIR    /tmp/build/perf/arch/x86/tests/
> >   CC       /tmp/build/perf/arch/x86/tests/arch-tests.o
> > <SNIP>
> >   CC       /tmp/build/perf/util/pmu.o
> >   CC       /tmp/build/perf/util/pmu-flex.o
> >   LD       /tmp/build/perf/util/libperf-in.o
> >   LD       /tmp/build/perf/libperf-in.o
> > Makefile:108: recipe for target 'install-bin' failed
> > make: *** [install-bin] Error 2
> > make: Leaving directory '/home/acme/git/linux/tools/perf'
> > [acme@jouet linux]$ 
> 
> how about following fix.. it gets rid of the -Wp,MT option completely
> so it should address Peter's issue.. it also makes fixdep more robust
> and makes it wait for first target before spitting out dependencies

So this should replace Peter's patch? On top? I'm checking that now...
 
> I have some difficulties now with getting Fedora 25.. I'll test
> and send this out within this week
> 
> jirka
> 
> 
> ---
> diff --git a/tools/build/Build.include b/tools/build/Build.include
> index c4ae12a5d0a5..63c898f089f7 100644
> --- a/tools/build/Build.include
> +++ b/tools/build/Build.include
> @@ -89,12 +89,12 @@ if_changed = $(if $(strip $(any-prereq) $(arg-check)),             \
>  # - per target C flags
>  # - per object C flags
>  # - BUILD_STR macro to allow '-D"$(variable)"' constructs
> -c_flags_1 = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
> +c_flags_1 = -Wp,-MD,$(depfile) $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
>  c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
>  c_flags   = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
> -cxx_flags = -Wp,-MD,$(depfile),-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
> +cxx_flags = -Wp,-MD,$(depfile) $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
>  
>  ###
>  ## HOSTCC C flags
>  
> -host_c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CHOSTFLAGS) -D"BUILD_STR(s)=\#s" $(CHOSTFLAGS_$(basetarget).o) $(CHOSTFLAGS_$(obj))
> +host_c_flags = -Wp,-MD,$(depfile) $(CHOSTFLAGS) -D"BUILD_STR(s)=\#s" $(CHOSTFLAGS_$(basetarget).o) $(CHOSTFLAGS_$(obj))
> diff --git a/tools/build/fixdep.c b/tools/build/fixdep.c
> index 1521d36cef0d..734d1547cbae 100644
> --- a/tools/build/fixdep.c
> +++ b/tools/build/fixdep.c
> @@ -49,7 +49,7 @@ static void parse_dep_file(void *map, size_t len)
>  	char *end = m + len;
>  	char *p;
>  	char s[PATH_MAX];
> -	int is_target;
> +	int is_target, has_target = 0;
>  	int saw_any_target = 0;
>  	int is_first_dep = 0;
>  
> @@ -67,7 +67,8 @@ static void parse_dep_file(void *map, size_t len)
>  		if (is_target) {
>  			/* The /next/ file is the first dependency */
>  			is_first_dep = 1;
> -		} else {
> +			has_target = 1;
> +		} else if (has_target) {
>  			/* Save this token/filename */
>  			memcpy(s, m, p-m);
>  			s[p - m] = 0;