[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #1 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Created attachment 33451
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33451&action=edit
The source to show the issue

[Bug c/63178] New: Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

            Bug ID: 63178
           Summary: Missed "incorrect-type-passed-to-function warning"
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gccbugs at dima dot secretsauce.net

Hi. I'm seeing that under particular conditions I can pass a wrong type into a
function, and no warning results. I'm attaching a minimized test case to show
this. There are two files: bugreport.c and bugreport.h. The .c includes the .h.
The issue only happens when the .h file is placed into /usr/include, and
included using <> instead of "".

bugreport.c has this snippet:


typedef ... sss_t;
int fff( sss_t* ctx, ... )
...
    sss_t* sss = NULL;
    fff(&sss,0,0);

So fff() expects a sss_t* as its first argument, but we're giving it a sss_t**
instead. This should generate a warning. However:

dima@shorty:/tmp$ gcc-4.9 -Wall -Wextra -c -o/dev/null bugreport.c
<no output>

So gcc thinks this is fine. Tweaking the test case even a little bit makes the
warning come back. For instance, including the header in the local directory,
instead of in /usr/include makes it work, as does simply putting the header the
contents into the .c and including nothing. Removing the F() call makes it
work. Changing the whitespace in the F() call makes it work.

I'm using gcc 4.9.1 as shipped on Debian/sid:

dima@shorty:/tmp$ dpkg -l gcc-4.9
ii  gcc-4.9                           4.9.1-1


dima@shorty:/tmp$ gcc-4.9 -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc-4.9
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.9/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.9.1-1'
--with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap
--disable-vtable-verify --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --with-arch-32=i586 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.9.1 (Debian 4.9.1-1) 


Thanks

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #2 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Created attachment 33452
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33452&action=edit
and the header

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2014-09-04
                 CC|                            |mpolacek at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think I fixed this in r214874.  Can you try to update your 4.9 gcc?

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #4 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Hi. Thank you for looking at this. I'm not set up to make bleeding-edge gcc
builds, so let me wait until Debian catches up, and I'll report back. Currently
they're on r214759 (not what the bug report mentions, but affected too), and
they update relatively often. Thanks again.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #5 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Hi.

I cherry-picked the commit you mentioned, rebuilt gcc, and the bug was not
resolved. Just in case I did something wrong in that process, I waited for
Debian to update their package. This just happened, and I updated. I'm now
using gcc4.9 version 4.9.1-13 from Debian/unstable. The Debian changelog says
this is using r215008:
http://metadata.ftp-master.debian.org/changelogs//main/g/gcc-4.9/gcc-4.9_4.9.1-13_changelog

As before, the bug is unresolved.

Thanks.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I've tried this again, and I still get the expected warning.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

Dima Kogan <gccbugs at dima dot secretsauce.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |INVALID

--- Comment #7 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Hi. Thank you once again for replying, Marek.

I just looked into this a bit more deeply, and it appears that this is some
sort of ccache artifact. Running without ccache I see the warning with all
versions of gcc that I have tried. With ccache, the warning is missing for all
gcc-4.9 and gcc-4.8 that I have, but it IS there with gcc-4.4.

So this sounds like a bug in ccache and not gcc. Sorry for the false alarm and
thank you very much for looking.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Ah, ccache, that settles it then.  NP, you're welcome.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

--- Comment #9 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
For the record, here's the ccache bug I just filed:
https://bugzilla.samba.org/show_bug.cgi?id=10819

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[gccbugs at dima dot secretsauce.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

Dima Kogan <gccbugs at dima dot secretsauce.net> changed:

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

--- Comment #10 from Dima Kogan <gccbugs at dima dot secretsauce.net> ---
Hi.

I filed this bug against ccache, and its maintainer had some insight and thinks
that this is a gcc issue after all. I'm reopening this bug here with the
salient portion of the comment from the ccache maintainer copied below. Thanks.


I would say that this is not a ccache bug. For ccache to work as expected in
its default operation mode, the compiler must be able to compile its own
preprocessed source code with the same result as compiling without the
preprocessing step.

In essence,

    compiler [OPTIONS] -E source.c -o source.i
    compiler [OPTIONS] -c source.i -o source.o

needs to give the same result as

    compiler [OPTIONS] -c source.c -o source.o

GCC doesn't do that for your test case:

    % gcc-4.9 -Wall -Wextra -E bugreport.c -o bugreport.i
    % gcc-4.9 -Wall -Wextra -c bugreport.i -o /dev/null
    % gcc-4.9 -Wall -Wextra -c bugreport.c -o /dev/null
    bugreport.c: In function ‘fn1’:
    bugreport.c:14:5: warning: passing argument 1 of ‘fff’ from incompatible
pointer type
     fff(&sss,0,0);
         ^
    bugreport.c:6:5: note: expected ‘struct sss_t *’ but argument is of type
‘struct sss_t **’
     int fff( sss_t* ctx, int a, int b);
         ^
    bugreport.c:15:1: warning: control reaches end of non-void function
[-Wreturn-type]
     }
     ^

.....

Digging a bit deeper, the behavior difference comes from this part of the
preprocessed output:

    % tail -n 11 bugreport.i
    int fn1()
    {
        sss_t* sss = ((void *)0);

        printf("%s %d",
     "bugreport.c"
    # 12 "bugreport.c" 3 4
        , 0 )
                      ;
        fff(&sss,0,0);
    }

The flag "3" after '# 12 "bugreport.c"' indicates that the following text comes
from a system header, which doesn't look right. (If bugreport.h is found
locally instead of in /usr/include, then the "3" flag disappears.) Sounds like
a GCC bug to me.
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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/63315] New: -fcompare-debug bootstrap issue in libjava (fixup_abnormal_edges related)
Date: Fri, 19 Sep 2014 19:46:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc315

            Bug ID: 63315
           Summary: -fcompare-debug bootstrap issue in libjava
                    (fixup_abnormal_edges related)
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: vmakarov at gcc dot gnu.org

In x86_64-linux trunk:
 ../configure --enable-languages=all,obj-c++,lto,go --disable-libcilkrts
 --enable-checking=release; GCC_COMPARE_DEBUG=1 make -j48 bootstrap > LOG 2>&1
 && GCC_COMPARE_DEBUG=1 make -j48 -k check > LOGC 2>&1; ../contrib/test_summary
 > LOGT 2>&1
bootstrap I'm seeing:
gcj: error: /tmp/ccb0xB2Sjx: -fcompare-debug failure (length)
make[3]: *** [gnu-xml-util.lo] Error 1
/usr/src/gcc/obj086/./gcc/gcj
-B/usr/src/gcc/obj086/x86_64-unknown-linux-gnu/libjava/
-B/usr/src/gcc/obj086/./gcc/ -B/usr/local/x86_64-unknown-linux-gnu/bin/
-B/usr/local/x86_64-unknown-linux-gnu/lib/ -isystem
/usr/local/x86_64-unknown-linux-gnu/include -isystem
/usr/local/x86_64-unknown-linux-gnu/sys-include    -fomit-frame-pointer -Usun
-fclasspath= -fbootclasspath=../../../libjava/classpath/lib --encoding=UTF-8
-Wno-deprecated -fbootstrap-classes -g -O2
-fsource-filename=/usr/src/gcc/obj086/x86_64-unknown-linux-gnu/libjava/classpath/lib/classes
-fjni -findirect-dispatch -fno-indirect-classes -c -o gnu-xml-util.lo
@gnu-xml-util.list -fcompare-debug --param min-nondebug-insn-uid\x10000
fails, with:
--- ccn5lLfzjx.gk.gkd   2014-09-19 17:40:51.443440651 +0200
+++ ccn5lLfzjx.gkd      2014-09-19 17:40:47.340440895 +0200
@@ -77215,6 +77215,7 @@ Declarations used by gnu.xml.util.XCat$C
 (note # 0 0 NOTE_INSN_DELETED)
 (note # 0 0 [bb 2] NOTE_INSN_BASIC_BLOCK)
 (note # 0 0 NOTE_INSN_FUNCTION_BEG)
+(note # 0 0 NOTE_INSN_DELETED)
 (insn/f:TI # 0 0 2 (set (mem:DI (pre_dec:DI (reg/f:DI 7 sp)) [  S8 A8])
         (reg:DI 44 r15))
/usr/src/gcc/libjava/classpath/gnu/xml/util/XCat.java:971# {*pushdi2_rex64}
      (expr_list:REG_DEAD (reg:DI 44 r15)
difference.

[Bug c/63178] Missed "incorrect-type-passed-to-function warning"

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63178

Andreas Schwab <schwab@linux-m68k.org> changed:

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

--- Comment #11 from Andreas Schwab <schwab@linux-m68k.org> ---
Dup of PR60100.

*** This bug has been marked as a duplicate of bug 60100 ***