re PR driver/50250 (Driver documentation on -l does not mention shared libraries)

2018-11-19  Sandra Loosemore  <sandra@codesourcery.com>

	PR driver/50250

	gcc/
	* doc/invoke.texi (Link Options): Mention shared libraries
	in documentation for the -l option.  Simplify discussion and
	point to the system linker documentation for details.

From-SVN: r266287

gcc/ChangeLog

+2018-11-19  Sandra Loosemore  <sandra@codesourcery.com>
+
+	PR driver/50250
+	* doc/invoke.texi (Link Options): Mention shared libraries
+	in documentation for the -l option.  Simplify discussion and
+	point to the system linker documentation for details.
+
 2018-11-19  Peter Bergner  <bergner@linux.ibm.com>
 
 	PR rtl-optimization/88033

gcc/doc/invoke.texi

@@ -12988,28 +12988,27 @@ Search the library named @var{library} when linking.  (The second
 alternative with the library as a separate argument is only for
 POSIX compliance and is not recommended.)
 
+The @option{-l} option is passed directly to the linker by GCC.  Refer
+to your linker documentation for exact details.  The general
+description below applies to the GNU linker.  
+
+The linker searches a standard list of directories for the library.
+The directories searched include several standard system directories
+plus any that you specify with @option{-L}.
+
+Static libraries are archives of object files, and have file names
+like @file{lib@var{library}.a}.  Some targets also support shared
+libraries, which typically have names like @file{lib@var{library}.so}.
+If both static and shared libraries are found, the linker gives
+preference to linking with the shared library unless the
+@option{-static} option is used.
+
 It makes a difference where in the command you write this option; the
 linker searches and processes libraries and object files in the order they
 are specified.  Thus, @samp{foo.o -lz bar.o} searches library @samp{z}
 after file @file{foo.o} but before @file{bar.o}.  If @file{bar.o} refers
 to functions in @samp{z}, those functions may not be loaded.
 
-The linker searches a standard list of directories for the library,
-which is actually a file named @file{lib@var{library}.a}.  The linker
-then uses this file as if it had been specified precisely by name.
-
-The directories searched include several standard system directories
-plus any that you specify with @option{-L}.
-
-Normally the files found this way are library files---archive files
-whose members are object files.  The linker handles an archive file by
-scanning through it for members which define symbols that have so far
-been referenced but not defined.  But if the file that is found is an
-ordinary object file, it is linked in the usual fashion.  The only
-difference between using an @option{-l} option and specifying a file name
-is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a}
-and searches several directories.
-
 @item -lobjc
 @opindex lobjc
 You need this special case of the @option{-l} option in order to