[Bug preprocessor/28435] New: -MMD vs not found system header (included from a system header)

[Bug preprocessor/28435] New: -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

I really don't know if this is a bug or not but it seems to be.
The steps to reproduce:
mkdir sys
cat >sys/t.h <<FOO
#include <bogus.h>
FOO
cat > t.c <<FOO
#include <t.h>
FOO
gcc -isystem sys t.c -MMD


And notice that this actually compiles successfully even though bougs.h does
not exist.  And removing the -MMD option, it actually fails.


-- 
           Summary: -MMD vs not found system header (included from a system
                    header)
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-07-19 14:06 -------
I forgot to say every GCC since at least 2.95.3, I tried has the same behavior.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2006-09-03 20:25 -------
This looks like the same bug as PR 22231.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |22231


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2006-10-03 15:56 -------
Confirmed via the dup bug.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-10-03 15:56:21
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-10-03 15:55 -------
*** Bug 29331 has been marked as a duplicate of this bug. ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gcc-bklyn at sneakemail dot
                   |                            |com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[matz at gcc dot gnu dot org]

------- Comment #5 from matz at gcc dot gnu dot org  2006-10-18 14:04 -------
The problem is in libcpp/files.c:open_file_failed.  It deliberately only
gives a warning when producing dependencies (and under some circumstances
doesn't even give a warning) for missing files.  I think it does that under
the assumption that the user gave only -M (with -E implied), so he would
be interested in the preprocessor output nevertheless, and that can be
produced even with missing deps.  The problem is, that giving -MD or -MMD
does not imply -E, i.e. the user really wants the deps to just be a
side-effect, as documented.  Probably libcpp needs another option which can
be set from the driver, which would make it produce errors instead of
warnings.


-- 

matz at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matz at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[tromey at gcc dot gnu dot org]

------- Comment #6 from tromey at gcc dot gnu dot org  2008-05-09 23:02 -------
I think we should give an error by default, and only *not* give an
error if -MG is passed.  My reasoning is that -MG exists only to disable
this error.  I couldn't think of a reason to disable it in other cases.
For instance, it seems to me that "gcc -E" should fail if a header is missing.

I looked at open_file_failed, but I don't understand the reasoning behind
a lot of the logic in there (though see PR 15220).

A comment says:

      /* If we are outputting dependencies but not for this file then
         don't error because we can still produce correct output.  */

... but this seems to be based on incorrect logic to me.  A <> include
may define something which affects later inclusions.

I wonder if anybody relies on the current, bogus, behavior.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at gcc dot gnu dot org]

------- Comment #7 from cgd at gcc dot gnu dot org  2009-09-19 06:15 -------
Subject: Bug 28435

Author: cgd
Date: Sat Sep 19 06:15:21 2009
New Revision: 151879

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=151879
Log:
[libcpp/ChangeLog]
2009-09-18  Chris Demetriou  <cgd@google.com>

        PR preprocessor/28435:
        * include/cpplib.h (struct cpp_options): Add new member
        deps.need_preprocessor_output.
        * files.c (open_file_failed): If preprocessor output is needed
        always report an error.

[gcc/ChangeLog]
2009-09-19  Chris Demetriou  <cgd@google.com>

        PR preprocessor/28435:
        * c-opts.c (c_common_handle_option): For -MD and -MMD, indicate
        to cpplib that the preprocessor output is needed.

[gcc/testsuite/ChangeLog]
2009-09-19  Chris Demetriou  <cgd@google.com>

        PR preprocessor/28435:
        * gcc.dg/cpp/missing-header-MD.c: New test.
        * gcc.dg/cpp/missing-header-MMD.c: New test.
        * gcc.dg/cpp/missing-sysheader-MD.c: New test.
        * gcc.dg/cpp/missing-sysheader-MMD.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/cpp/missing-header-MD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-header-MMD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-sysheader-MD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-sysheader-MMD.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-opts.c
    trunk/gcc/testsuite/ChangeLog
    trunk/libcpp/ChangeLog
    trunk/libcpp/files.c
    trunk/libcpp/include/cpplib.h


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at gcc dot gnu dot org]

------- Comment #8 from cgd at gcc dot gnu dot org  2009-09-19 19:26 -------
Fixed in trunk in rev 151879.


-- 

cgd at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |cgd at gcc dot gnu dot org
             Status|NEW                         |RESOLVED
           Keywords|                            |patch
      Known to fail|                            |4.2.0 4.2.1 4.2.2 4.3.1
                   |                            |4.4.0
         Resolution|                            |FIXED
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[hjl dot tools at gmail dot com]

------- Comment #9 from hjl dot tools at gmail dot com  2009-09-19 21:47 -------
On Linux/ia32, Linux/ia64 and Linux/Intel64, I got

FAIL: gcc.dg/cpp/missing-header-MD.c  (test for errors, line 5)
FAIL: gcc.dg/cpp/missing-header-MD.c (test for excess errors)
FAIL: gcc.dg/cpp/missing-header-MMD.c  (test for errors, line 5)
FAIL: gcc.dg/cpp/missing-header-MMD.c (test for excess errors)
FAIL: gcc.dg/cpp/missing-sysheader-MD.c  (test for errors, line 5)
FAIL: gcc.dg/cpp/missing-sysheader-MD.c (test for excess errors)
FAIL: gcc.dg/cpp/missing-sysheader-MMD.c  (test for errors, line 5)
FAIL: gcc.dg/cpp/missing-sysheader-MMD.c (test for excess errors)


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2006-10-03 15:56:21         |2009-09-19 21:47:02
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[hjl dot tools at gmail dot com]

------- Comment #10 from hjl dot tools at gmail dot com  2009-09-19 21:47 -------
All new tests are failing.


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at google dot com]

------- Comment #11 from cgd at google dot com  2009-09-20 01:34 -------
Subject: Re:  -MMD vs not found system header 
        (included from a system header)

Gack, sorry, looks like I screwed this up.

When I retested after updating, I only compared test results
before/after, and saw what I was expecting, I didn't actually recheck
all of the output from the new tests.

I'll see about fixing ASAP.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at gcc dot gnu dot org]

------- Comment #12 from cgd at gcc dot gnu dot org  2009-09-20 01:57 -------
(In reply to comment #11)
> Gack, sorry, looks like I screwed this up.
> 
> When I retested after updating, I only compared test results
> before/after, and saw what I was expecting, I didn't actually recheck
> all of the output from the new tests.

Actually, it looking at this error further, I can't see how the new tests ever
passed in trunk.

(I initially wrote this in 4.4.0, where I definitely verified that all of the
tests passed... but the 'fatal error' bit was changed in trunk, and so I had to
change the tests.  And I know that I diffed the test results in trunk, but I
can only conclude that I never actually verified that they all passed in trunk.
 *sigh*)

Anyway, testing the fix now (copying the error-checking style from the current
missing-header-1 test).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at gcc dot gnu dot org]

------- Comment #13 from cgd at gcc dot gnu dot org  2009-09-20 08:08 -------
Subject: Bug 28435

Author: cgd
Date: Sun Sep 20 08:08:06 2009
New Revision: 151894

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=151894
Log:
[gcc/testsuite/ChangeLog]
2009-09-20  Chris Demetriou  <cgd@google.com>

        PR preprocessor/28435:
        * gcc.dg/cpp/missing-header-MD.c: Make output checking match
        gcc.dg/cpp/missing-header-1.c, and add PR number to test comment.
        * gcc.dg/cpp/missing-header-MMD.c: Likewise.
        * gcc.dg/cpp/missing-sysheader-MD.c: Likewise.
        * gcc.dg/cpp/missing-sysheader-MMD.c: Likewise.

Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/cpp/missing-header-MD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-header-MMD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-sysheader-MD.c
    trunk/gcc/testsuite/gcc.dg/cpp/missing-sysheader-MMD.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at gcc dot gnu dot org]

------- Comment #14 from cgd at gcc dot gnu dot org  2009-09-20 08:10 -------
HJ, I believe I've fixed the tests now:

PASS: gcc.dg/cpp/missing-header-MD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-header-MD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-header-MD.c (test for excess errors)
PASS: gcc.dg/cpp/missing-header-MMD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-header-MMD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-header-MMD.c (test for excess errors)
PASS: gcc.dg/cpp/missing-sysheader-MD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-sysheader-MD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-sysheader-MD.c (test for excess errors)
PASS: gcc.dg/cpp/missing-sysheader-MMD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-sysheader-MMD.c  (test for warnings, line )
PASS: gcc.dg/cpp/missing-sysheader-MMD.c (test for excess errors)

thanks for letting me know.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu dot org]

------- Comment #15 from pinskia at gcc dot gnu dot org  2010-02-07 20:33 -------
*** Bug 42921 has been marked as a duplicate of this bug. ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rhansen at bbn dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[cgd at google dot com]

------- Comment #16 from cgd at google dot com  2010-02-07 21:24 -------
(In reply to comment #15)
> *** Bug 42921 has been marked as a duplicate of this bug. ***
> 

FWIW, I actually think that's a different issue (though certainly related).

this bug was all about -MD and -MMD -- and what happens when an object file
needs to be output, but cannot be because of a missing include.

AFAICT, that bug is all about, what should the handling of -MM be vs. missing
system headers.

That having been said, I will note that with:
gcc version 3.4.4 (cygming special, gdc 0.12, using dmd 0.125)

you get the results:

[cgd@laptop tmp]$ echo "#include <does_not_exist.h>" > foo.c
[cgd@laptop tmp]$ gcc -MM -MF foo.d foo.c && echo succeeded || echo failed
foo.c:1:28: does_not_exist.h: No such file or directory
failed
[cgd@laptop tmp]$ echo '#include "does_not_exist.h"' > foo.c
[cgd@laptop tmp]$ gcc -MM -MF foo.d foo.c && echo succeeded || echo failed
foo.c:1:28: does_not_exist.h: No such file or directory
failed

So this certainly used to behave as the submitter of 42921 expected at *some*
point.

As of 4.2.2 (the next version I have handy after 3.4.4) the first case reported
"succeeded" (and the second failed).

--cgd


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[rguenth at gcc dot gnu dot org]

------- Comment #17 from rguenth at gcc dot gnu dot org  2010-04-06 11:19 -------
GCC 4.5.0 is being released.  Deferring to 4.5.1.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.5.0                       |4.5.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[rguenth at gcc dot gnu dot org]

------- Comment #18 from rguenth at gcc dot gnu dot org  2010-07-31 09:29 -------
GCC 4.5.1 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.5.1                       |4.5.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.5.3                       |4.5.0
      Known to fail|                            |

--- Comment #20 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-12 20:26:59 UTC ---
Fixed so closing.

[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.5.2                       |4.5.3

--- Comment #19 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-12-16 13:03:23 UTC ---
GCC 4.5.2 is being released, adjusting target milestone.