Fix -Os putc_unlocked, fputc_unlocked linknamespace, localplt issues (bug 15105, bug 19463)

  Continuing the fixes for linknamespace and localplt test failures with
-Os that arise from functions not being inlined in that case, this
patch fixes such failures for putc_unlocked and fputc_unlocked.  This
is relative to a tree with
<https://sourceware.org/ml/libc-alpha/2018-02/msg00475.html> (pending
review) applied, but has only trivial textual dependence on that
patch.

libc_hidden_* are used for both functions, while namespace issues are
addressed by making putc_unlocked a weak alias of hidden
__putc_unlocked, which is called in the one place where namespace
issues arise (and defined as an inline function in include/stdio.h).

Tested for x86_64 (both without -Os to make sure that case continues
to work, and with -Os to make sure all the relevant linknamespace and
localplt test failures are resolved).  This completes fixing the -Os
linknamespace failures (at least for x86_64); localplt failures remain
after this patch.

2018-02-19  Joseph Myers  <joseph@codesourcery.com>

	[BZ #15105]
	[BZ #19463]
	* libio/fputc_u.c (fputc_unlocked): Use libc_hidden_def.
	* libio/putc_u.c (putc_unlocked): Rename to __putc_unlocked and
	define as weak alias of __putc_unlocked.  Use libc_hidden_weak.
	* include/stdio.h [!_ISOMAC] (fputc_unlocked): Use
	libc_hidden_proto.
	[!_ISOMAC] (putc_unlocked): Likewise.
	[!_ISOMAC] (__putc_unlocked): Declare as hidden function, and
	define inline if [__USE_EXTERN_INLINES].
	* misc/syslog.c (__vsyslog_chk): Call __putc_unlocked instead of
	putc_unlocked.
  

On 19/02/2018 15:08, Joseph Myers wrote:
> Continuing the fixes for linknamespace and localplt test failures with
> -Os that arise from functions not being inlined in that case, this
> patch fixes such failures for putc_unlocked and fputc_unlocked.  This
> is relative to a tree with
> <https://sourceware.org/ml/libc-alpha/2018-02/msg00475.html> (pending
> review) applied, but has only trivial textual dependence on that
> patch.
> 
> libc_hidden_* are used for both functions, while namespace issues are
> addressed by making putc_unlocked a weak alias of hidden
> __putc_unlocked, which is called in the one place where namespace
> issues arise (and defined as an inline function in include/stdio.h).
> 
> Tested for x86_64 (both without -Os to make sure that case continues
> to work, and with -Os to make sure all the relevant linknamespace and
> localplt test failures are resolved).  This completes fixing the -Os
> linknamespace failures (at least for x86_64); localplt failures remain
> after this patch.
> 
> 2018-02-19  Joseph Myers  <joseph@codesourcery.com>
> 
> 	[BZ #15105]
> 	[BZ #19463]
> 	* libio/fputc_u.c (fputc_unlocked): Use libc_hidden_def.
> 	* libio/putc_u.c (putc_unlocked): Rename to __putc_unlocked and
> 	define as weak alias of __putc_unlocked.  Use libc_hidden_weak.
> 	* include/stdio.h [!_ISOMAC] (fputc_unlocked): Use
> 	libc_hidden_proto.
> 	[!_ISOMAC] (putc_unlocked): Likewise.
> 	[!_ISOMAC] (__putc_unlocked): Declare as hidden function, and
> 	define inline if [__USE_EXTERN_INLINES].
> 	* misc/syslog.c (__vsyslog_chk): Call __putc_unlocked instead of
> 	putc_unlocked.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

> 
> diff --git a/include/stdio.h b/include/stdio.h
> index 937235f..aac5acd 100644
> --- a/include/stdio.h
> +++ b/include/stdio.h
> @@ -188,6 +188,9 @@ extern __typeof (feof_unlocked) __feof_unlocked attribute_hidden;
>  libc_hidden_proto (ferror_unlocked)
>  extern __typeof (ferror_unlocked) __ferror_unlocked attribute_hidden;
>  libc_hidden_proto (getc_unlocked)
> +libc_hidden_proto (fputc_unlocked)
> +libc_hidden_proto (putc_unlocked)
> +extern __typeof (putc_unlocked) __putc_unlocked attribute_hidden;
>  libc_hidden_proto (fmemopen)
>  /* The prototype needs repeating instead of using __typeof to use
>     __THROW in C++ tests.  */
> @@ -226,6 +229,12 @@ __getc_unlocked (FILE *__fp)
>  {
>    return __getc_unlocked_body (__fp);
>  }
> +
> +__extern_inline int
> +__putc_unlocked (int __c, FILE *__stream)
> +{
> +  return __putc_unlocked_body (__c, __stream);
> +}
>  #  endif
>  
>  # endif /* not _ISOMAC */
> diff --git a/libio/fputc_u.c b/libio/fputc_u.c
> index abe07f3..25e2035 100644
> --- a/libio/fputc_u.c
> +++ b/libio/fputc_u.c
> @@ -35,3 +35,4 @@ fputc_unlocked (int c, _IO_FILE *fp)
>    CHECK_FILE (fp, EOF);
>    return _IO_putc_unlocked (c, fp);
>  }
> +libc_hidden_def (fputc_unlocked)
> diff --git a/libio/putc_u.c b/libio/putc_u.c
> index 61ca95b..2d122a6 100644
> --- a/libio/putc_u.c
> +++ b/libio/putc_u.c
> @@ -21,8 +21,10 @@
>  #undef putc_unlocked
>  
>  int
> -putc_unlocked (int c, _IO_FILE *fp)
> +__putc_unlocked (int c, _IO_FILE *fp)
>  {
>    CHECK_FILE (fp, EOF);
>    return _IO_putc_unlocked (c, fp);
>  }
> +weak_alias (__putc_unlocked, putc_unlocked)
> +libc_hidden_weak (putc_unlocked)
> diff --git a/misc/syslog.c b/misc/syslog.c
> index 2b6bd37..644dbe8 100644
> --- a/misc/syslog.c
> +++ b/misc/syslog.c
> @@ -207,8 +207,8 @@ __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
>  	      fprintf (f, "[%d]", (int) __getpid ());
>  	    if (LogTag != NULL)
>  	      {
> -		putc_unlocked (':', f);
> -		putc_unlocked (' ', f);
> +		__putc_unlocked (':', f);
> +		__putc_unlocked (' ', f);
>  	      }
>  
>  	    /* Restore errno for %m format.  */
>