Re: [PATCH v4 04/20] add configury

[Gerald Pfeifer <gerald at pfeifer dot com>]

Hi Tom,

On Mon, 23 Sep 2013, Tom Tromey wrote:
> This adds the configury needed for automatic dependency tracking.  It
> also adds some bits to the Makefile so we can begin converting
> (removing) explicit dependencies.
> 
> 	* Makefile.in (CCDEPMODE, DEPDIR, depcomp, COMPILE.base)
> 	(COMPILE, POSTCOMPILE): New variables.
> 	(.cc.o .c.o): Use COMPILE, POSTCOMPILE.

I believe this may be breaking all my testers on FreeBSD 
(i386-unknown-freebsd10.0 for example).  The timing of when this
patchset went in fits pretty much when my builds started to break
and I am wondering about some code.

Here is the failure mode:

gmake[2]: Entering directory `/scratch/tmp/gerald/OBJ-0927-1848/gcc'
g++ -c  -DIN_GCC_FRONTEND -g -O2 -DIN_GCC   -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wmissing-format-attribute -pedantic -Wno-long-long
-Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common
-DHAVE_CONFIG_H -I. -Ic -I/scratch/tmp/gerald/gcc-HEAD/gcc ...[-I 
options]...
-o c/c-lang.o -MT c/c-lang.o -MMD -MP -MF c/.deps/c-lang.TPo
/scratch/tmp/gerald/gcc-HEAD/gcc/c/c-lang.c
cc1plus: error: unrecognized command line option "-Wno-narrowing"
gmake[2]: *** [c/c-lang.o] Error 1
gmake[1]: *** [install-gcc] Error 2
gmake: *** [install] Error 2

The issue is the invocation of g++ (the old system compiler, not what
we built) with -Wno-narrowing (a new option).

And looking at the code, I see

  +COMPILE.base = $(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) -o $@
  +ifeq ($(CCDEPMODE),depmode=gcc3)
  +# Note a subtlety here: we use $(@D) for the directory part, to make
  +# things like the go/%.o rule work properly; but we use $(*F) for the
  +# file part, as we just want the file part of the stem, not the entire
  +# file name.
  +COMPILE = $(COMPILE.base) -MT $@ -MMD -MP -MF $(@D)/$(DEPDIR)/$(*F).TPo
  +POSTCOMPILE = @mv $(@D)/$(DEPDIR)/$(*F).TPo $(@D)/$(DEPDIR)/$(*F).Po
  +else
  +COMPILE = source='$<' object='$@' libtool=no \
  +    DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) $(COMPILE.base)
  +POSTCOMPILE =
  +endif

Where does $(ALL_COMPILERFLAGS) compile from?  If I read the code
right, we do disable these warnings for the stage1 build.  However,
the install compiler is the same -- so I guess we should disable
warnings there, too?

Gerald