[Bug c/29172] New: --combine can't handle #pragma once

[Bug c/29172] New: --combine can't handle #pragma once

[acahalan at gmail dot com]

The --combine option fails to forget the "once" property of a header file when
gcc moves on to dealing with the next *.c file. The pragma should function just
the same as the usual "#ifndef _SOME_ARBITRARY_CRAP" hack.

k 0 $ cat once.h
#pragma once
#define D
k 0 $ cat a.c
#include "once.h"
#ifndef D
#error No def in a.c!
#endif
k 0 $ cat b.c
#include "once.h"
#ifndef D
#error No def in b.c!
#endif
k 0 $ gcc --combine a.c b.c
b.c:3:2: error: #error No def in b.c!
k 1 $ gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-libgcj-multifile
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk
--disable-dssi --enable-plugin
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-cpu=generic
--host=x86_64-redhat-linux
Thread model: posix
gcc version 4.1.1 20060828 (Red Hat 4.1.1-20)
k 0 $


-- 
           Summary: --combine can't handle #pragma once
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: acahalan at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-09-21 18:34 -------
I bet the C front-end forgot to tell the preprocessor to rest the "pragma once"
table.


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[acahalan at gmail dot com]

------- Comment #2 from acahalan at gmail dot com  2006-10-19 05:28 -------
Why is this still UNCONFIRMED, and why is it marked enhancement?

The compiler is failing to follow the documented behavior.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-12-05 23:15 -------
(In reply to comment #2)
> The compiler is failing to follow the documented behavior.
Because I (or anyone else) have not got around to actually testing the testcase
:).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[acahalan at gmail dot com]

------- Comment #4 from acahalan at gmail dot com  2006-12-06 04:07 -------
(In reply to comment #3)
> (In reply to comment #2)
> > The compiler is failing to follow the documented behavior.
> Because I (or anyone else) have not got around to actually testing the testcase
> :).

I still don't see how this is an enhancement.

The compiler is documented to behave one way. It does something else.
That's not "add my new pet feature". That's "you have a clear defect".
Supposedly gcc supports "#pragma once" (it seems to, and is documented
as such) and supposedly gcc supports "--combine" (it seems to, kind of,
aside from the many bugs, but at least this feature is documented).
Nothing says that these features cause each other to break horribly,
yet they do.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[tromey at gcc dot gnu dot org]

------- Comment #5 from tromey at gcc dot gnu dot org  2007-09-27 22:04 -------
Confirmed.
The problem is that the loop in c_common_parse_file calls
cpp_undef_all -- which undefines all symbols but does not
mark _cpp_file objects as not seen.
We probably need a new libcpp API for this.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-09-27 22:04:24
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[tromey at gcc dot gnu dot org]

------- Comment #6 from tromey at gcc dot gnu dot org  2007-11-12 20:24 -------
Testing a patch.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |tromey at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-09-27 22:04:24         |2007-11-12 20:24:41
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[tromey at gcc dot gnu dot org]

------- Comment #7 from tromey at gcc dot gnu dot org  2007-12-06 18:56 -------
Subject: Bug 29172

Author: tromey
Date: Thu Dec  6 18:56:26 2007
New Revision: 130656

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=130656
Log:
gcc
        PR c/29172:
        * c-opts.c (c_common_parse_file): Call cpp_clear_file_cache.
libcpp
        PR c/29172:
        * internal.h (struct cpp_reader) <file_hash_entries>: Changed
        type.
        <file_hash_entries_allocated, file_hash_entries_used>: Removed.
        * files.c (FILE_HASH_POOL_SIZE): New macro.
        (struct file_hash_entry_pool): New.
        (destroy_all_cpp_files): New function.
        (allocate_file_hash_entries): Allocate a file_hash_entry_pool.
        (new_file_hash_entry): Update.
        (free_file_hash_entries): New function.
        (_cpp_cleanup_files): Call free_file_hash_entries and
        destroy_all_cpp_files.
        (cpp_clear_file_cache): New function.
        * include/cpplib.h (cpp_clear_file_cache): Declare.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-opts.c
    trunk/libcpp/ChangeLog
    trunk/libcpp/files.c
    trunk/libcpp/include/cpplib.h
    trunk/libcpp/internal.h


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[tromey at gcc dot gnu dot org]

------- Comment #8 from tromey at gcc dot gnu dot org  2007-12-06 18:58 -------
Fixed on trunk.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.3.0
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172

[Bug c/29172] --combine can't handle #pragma once

[pinskia at gcc dot gnu dot org]

------- Comment #9 from pinskia at gcc dot gnu dot org  2007-12-08 20:11 -------
Fixed so closing.


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pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29172