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Re: preprocessor/3951: need for -MF w/ -M breaks backward compat. w/ documented features.
- From: Neil Booth <neil at daikokuya dot demon dot co dot uk>
- To: neil at gcc dot gnu dot org
- Cc: gcc-prs at gcc dot gnu dot org,
- Date: 23 Mar 2002 13:26:01 -0000
- Subject: Re: preprocessor/3951: need for -MF w/ -M breaks backward compat. w/ documented features.
- Reply-to: Neil Booth <neil at daikokuya dot demon dot co dot uk>
The following reply was made to PR preprocessor/3951; it has been noted by GNATS.
From: Neil Booth <neil@daikokuya.demon.co.uk>
To: cgd@broadcom.com
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: preprocessor/3951: need for -MF w/ -M breaks backward compat. w/ documented features.
Date: Sat, 23 Mar 2002 13:16:56 +0000
I've cc-ed GNATS.
Chris G. Demetriou wrote:-
> On further testing, not sure that all is happy in 3.0.x with the
> matches that you made. (I didn't cc the list/gnats on this, but if
> you'd like feel free to fwd this msg there.)
>
>
> It could be that i've goofed them up applying them to my source tree,
> but I don't _think_ I did.
>
>
> For a file foo.c and foo.S with 'junk' contents, what does:
>
> gcc -MMD -c -o foo.o $@
>
> produce for you?
>
> similarly, what if you say "-E" instead of -c?
>
>
> in my little world, for the .c / -c case, things are fine.
>
> for the .c / -E, .S / -c, and .S / -E cases, the the preprocessed
> output is zero-length (leading to ... not the right thing in the .S /
> -c case, especially 8-).
Wah! It works now! And with -save-temps!! Happy!!! I've done
everything I can think of to break it, and compared everything with
2.95.4; and it's all matching.
The final patch I sent you seems to be the holy grail. It gets the
above right, fixes the 2.95 issues we wanted to avoid, and handles -MF,
-MQ and -MT like we want. For the benefit of GNATS, I'll reproduce the
patch below. If you could confirm this fixes this issue once and for
all, I'll apply it to all 3 trees.
Thanks for persevering!
Neil.
Index: gcc.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/gcc.c,v
retrieving revision 1.205.2.26
diff -u -p -r1.205.2.26 gcc.c
--- gcc.c 2002/03/11 21:38:14 1.205.2.26
+++ gcc.c 2002/03/23 12:07:37
@@ -596,8 +596,8 @@ static const char *cpp_options =
"%{C:%{!E:%eGNU C does not support -C without using -E}}\
%{std*} %{nostdinc*}\
%{C} %{v} %{I*} %{P} %{$} %I\
- %{MD:-M -MF %W{!o: %b.d}%W{o*:%.d%*}}\
- %{MMD:-MM -MF %W{!o: %b.d}%W{o*:%.d%*}}\
+ %{MD:-MD %W{!o: %b.d}%W{o*:%.d%*}}\
+ %{MMD:-MMD %W{!o: %b.d}%W{o*:%.d%*}}\
%{M} %{MM} %W{MF*} %{MG} %{MP} %{MQ*} %{MT*}\
%{!E:%{!M:%{!MM:%{MD|MMD:%{o*:-MQ %*}}}}}\
%{!no-gcc:-D__GNUC__=%v1 -D__GNUC_MINOR__=%v2 -D__GNUC_PATCHLEVEL__=%v3}\
Index: cppinit.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cppinit.c,v
retrieving revision 1.147.2.12
diff -u -p -r1.147.2.12 cppinit.c
--- cppinit.c 2002/03/11 21:38:18 1.147.2.12
+++ cppinit.c 2002/03/23 12:07:41
@@ -1459,10 +1459,16 @@ cpp_handle_option (pfile, argc, argv)
CPP_OPTION (pfile, print_deps_missing_files) = 1;
break;
case OPT_M:
+ /* When doing dependencies with -M or -MM, suppress normal
+ preprocessed output, but still do -dM etc. as software
+ depends on this. Preprocessed output occurs if -MD, -MMD
+ or environment var dependency generation is used. */
CPP_OPTION (pfile, print_deps) = 2;
+ CPP_OPTION (pfile, no_output) = 1;
break;
case OPT_MM:
CPP_OPTION (pfile, print_deps) = 1;
+ CPP_OPTION (pfile, no_output) = 1;
break;
case OPT_MF:
CPP_OPTION (pfile, deps_file) = arg;
@@ -1476,12 +1482,6 @@ cpp_handle_option (pfile, argc, argv)
deps_add_target (pfile->deps, arg, opt_code == OPT_MQ);
break;
- /* -MD and -MMD for cpp0 are deprecated and undocumented
- (use -M or -MM with -MF instead), and probably should be
- removed with the next major GCC version. For the moment
- we allow these for the benefit of Automake 1.4, which
- uses these when dependency tracking is enabled. Automake
- 1.5 will fix this. */
case OPT_MD:
CPP_OPTION (pfile, print_deps) = 2;
CPP_OPTION (pfile, deps_file) = arg;
@@ -1786,10 +1786,6 @@ init_dependency_output (pfile)
/* If -M or -MM was seen, default output to wherever was specified
with -o. out_fname is non-NULL here. */
CPP_OPTION (pfile, deps_file) = CPP_OPTION (pfile, out_fname);
-
- /* When doing dependencies, suppress normal preprocessed output.
- Still do -dM, -dI etc. as e.g. glibc depends on this. */
- CPP_OPTION (pfile, no_output) = 1;
}
static void