[PATCH] Add missing headers to fix implicit function defns

[PATCH] Add missing headers to fix implicit function defns

[Pat Pannuto]

A few files were missing headers for memset/malloc, likely missed
because the files don't directly call the functions, rather they
come in via macros in libc/include/sys/reent.h:

    #define _REENT_CHECK(var, what, type, size, init) do { \
      struct _reent *_r = (var); \
      if (_r->what == NULL) { \
        _r->what = (type)malloc(size); \

    #define _REENT_CHECK_ASCTIME_BUF(var) \
      _REENT_CHECK(var, _asctime_buf, char *, _REENT_ASCTIME_SIZE, \
        memset((var)->_asctime_buf, 0, _REENT_ASCTIME_SIZE))

Without these fixes, implicit function signatures are provided,
which gcc warns could cause aliasing issues down the line:

    ../../../../../../../newlib-2.5.0/newlib/libc/time/asctime.c:62:3: warning: type of 'memset' does not match original declaration [-Wlto-type-mismatch]
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/string.h:29:7: note: return value type mismatch
     _PTR  _EXFUN(memset,(_PTR, int, size_t));
           ^
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/string.h:29:7: note: 'memset' was previously declared here
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/string.h:29:7: note: code may be misoptimized unless -fno-strict-aliasing is used
    ../../../../../../../newlib-2.5.0/newlib/libc/time/asctime.c:62:3: warning: type of 'malloc' does not match original declaration [-Wlto-type-mismatch]
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: return value type mismatch
     extern _PTR malloc _PARAMS ((size_t));
                 ^
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: 'malloc' was previously declared here
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: code may be misoptimized unless -fno-strict-aliasing is used

    ../../../../../../../newlib-2.5.0/newlib/libc/time/lcltime.c:58:3: warning: type of 'malloc' does not match original declaration [-Wlto-type-mismatch]
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: return value type mismatch
     extern _PTR malloc _PARAMS ((size_t));
                 ^
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: 'malloc' was previously declared here
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: code may be misoptimized unless -fno-strict-aliasing is used

    ../../../../../../../newlib-2.5.0/newlib/libc/string/strsignal.c:70:3: warning: type of 'malloc' does not match original declaration [-Wlto-type-mismatch]
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: return value type mismatch
     extern _PTR malloc _PARAMS ((size_t));
                 ^
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: 'malloc' was previously declared here
    /Volumes/code/external/newlib-cygwin/newlib/libc/include/malloc.h:37:13: note: code may be misoptimized unless -fno-strict-aliasing is used

Including the proper headers elminates the implicit function
signatures and these warnings.
---
 newlib/libc/string/strsignal.c | 1 +
 newlib/libc/string/strtok.c    | 1 +
 newlib/libc/time/asctime.c     | 2 ++
 newlib/libc/time/lcltime.c     | 1 +
 4 files changed, 5 insertions(+)

diff --git a/newlib/libc/string/strsignal.c b/newlib/libc/string/strsignal.c
index e03c1086b..94ae26db1 100644
--- a/newlib/libc/string/strsignal.c
+++ b/newlib/libc/string/strsignal.c
@@ -56,6 +56,7 @@ QUICKREF
 #include <string.h>
 #include <signal.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <reent.h>
 
 char *
diff --git a/newlib/libc/string/strtok.c b/newlib/libc/string/strtok.c
index 21607e04a..8d07ab387 100644
--- a/newlib/libc/string/strtok.c
+++ b/newlib/libc/string/strtok.c
@@ -85,6 +85,7 @@ QUICKREF
 /* undef STRICT_ANSI so that strtok_r prototype will be defined */
 #undef  __STRICT_ANSI__
 #include <string.h>
+#include <stdlib.h>
 #include <_ansi.h>
 #include <reent.h>
 
diff --git a/newlib/libc/time/asctime.c b/newlib/libc/time/asctime.c
index 024310bbf..f56b511b8 100644
--- a/newlib/libc/time/asctime.c
+++ b/newlib/libc/time/asctime.c
@@ -47,6 +47,8 @@ ANSI C requires <<asctime>>.
 <<asctime>> requires no supporting OS subroutines.
 */
 
+#include <stdlib.h>
+#include <string.h>
 #include <time.h>
 #include <_ansi.h>
 #include <reent.h>
diff --git a/newlib/libc/time/lcltime.c b/newlib/libc/time/lcltime.c
index 16162bfb0..2c9a25fd7 100644
--- a/newlib/libc/time/lcltime.c
+++ b/newlib/libc/time/lcltime.c
@@ -44,6 +44,7 @@ ANSI C requires <<localtime>>.
 <<localtime>> requires no supporting OS subroutines.
 */
 
+#include <stdlib.h>
 #include <time.h>
 #include <reent.h>
 
-- 
2.11.0

Re: [PATCH] Add missing headers to fix implicit function defns

[Corinna Vinschen]

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On Jan 15 19:12, Pat Pannuto wrote:
> A few files were missing headers for memset/malloc, likely missed
> because the files don't directly call the functions, rather they
> come in via macros in libc/include/sys/reent.h:
> [...]

Patch applied.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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Re: [PATCH] Add missing headers to fix implicit function defns

[Hans-Bernhard Bröker]

Am 16.01.2017 um 01:12 schrieb Pat Pannuto:
> A few files were missing headers for memset/malloc, likely missed
> because the files don't directly call the functions, rather they
> come in via macros in libc/include/sys/reent.h:

Shouldn't then <sys/reent.h> be including <string.h> and <stdlib.h> 
itself, to be done with it?

If a header defines macros which reference things provided by other 
headers, it should make sure those other things are known, i.e. it 
should include those other headers.

Re: [PATCH] Add missing headers to fix implicit function defns

[Pat Pannuto]

Quite possibly. This warning at the top of <sys/reent.h> made me nervous as I
don't have a handle on exactly what reent.h is doing and how it plays with other
headers:

/* WARNING: All identifiers here must begin with an underscore.  This file is
   included by stdio.h and others and we therefore must only use identifiers
   in the namespace allotted to us.  */

So I went with the more conservative change. If you have a deeper understanding
and including other std* headers in reent.h is safe, then I agree it's
probably a
better fix.

On Mon, Jan 16, 2017 at 4:21 PM, Hans-Bernhard Bröker
<HBBroeker@t-online.de> wrote:
> Am 16.01.2017 um 01:12 schrieb Pat Pannuto:
>>
>> A few files were missing headers for memset/malloc, likely missed
>> because the files don't directly call the functions, rather they
>> come in via macros in libc/include/sys/reent.h:
>
>
> Shouldn't then <sys/reent.h> be including <string.h> and <stdlib.h> itself,
> to be done with it?
>
> If a header defines macros which reference things provided by other headers,
> it should make sure those other things are known, i.e. it should include
> those other headers.
>

Re: [PATCH] Add missing headers to fix implicit function defns

[Sebastian Huber]

On 16/01/17 22:21, Hans-Bernhard Bröker wrote:
> Am 16.01.2017 um 01:12 schrieb Pat Pannuto:
>> A few files were missing headers for memset/malloc, likely missed
>> because the files don't directly call the functions, rather they
>> come in via macros in libc/include/sys/reent.h:
>
> Shouldn't then <sys/reent.h> be including <string.h> and <stdlib.h> 
> itself, to be done with it?
>
> If a header defines macros which reference things provided by other 
> headers, it should make sure those other things are known, i.e. it 
> should include those other headers.

No, this would lead to cyclic dependencies (<stdlib.h> includes 
<sys/reent.h>) and would make <string.h> and <stdlib.h> unnecessarily 
visible via unrelated standard header files.

-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
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Fax     : +49 89 189 47 41-09
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Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.

Re: [PATCH] Add missing headers to fix implicit function defns

[Hans-Bernhard Bröker]

Am 17.01.2017 um 11:08 schrieb Sebastian Huber:
> On 16/01/17 22:21, Hans-Bernhard Bröker wrote:
>> Am 16.01.2017 um 01:12 schrieb Pat Pannuto:

>> If a header defines macros which reference things provided by other
>> headers, it should make sure those other things are known, i.e. it
>> should include those other headers.

> No, this would lead to cyclic dependencies (<stdlib.h> includes
> <sys/reent.h>) and would make <string.h> and <stdlib.h> unnecessarily
> visible via unrelated standard header files.

Indeed.  I had found that out, too, in the meantime, but forgot to CC: 
the list in the reply.

But that does mean there's already a cyclic header dependency now, 
introduced by <sys/reent.h> referencing to stuff from <string.h>, while 
<string.h> includes <sys/reent.h> (smae for <stdlib.h>).  That should 
really be avoided, if at all possible.  Usually, this would mean that 
the actual declarations/definitions of malloc() and memset() should be 
in separate header fragments, to be included by both <sys/reent.h> and 
<stdlib.h>/<string.h>, respectively.

Could this mean that many of the 274 occurences of #include <reent.h> in 
the *.c files could actually be dropped, since what those sources really 
need out of it is already provided indirectly by their includes of 
<stdio.h>, <string.h>, etc.?  In a small experimen the 4 files modified 
by this patch, and the Cygwin build of newlib, removing their #include 
<reent.h> didn't appear to break the build...