[patch+7.9] compile: Filter out -fpreprocessed

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

with global system gcc-5.0 if one also installs ccache (needing a different
patch for -fplugin=libcc1plugin) it breaks as GDB will read from inferior
DW_AT_producer containing -fpreprocessed (due to ccache used to compile the
inferior).
    <c>   DW_AT_producer    : (indirect string, offset: 0x52): GNU C11 5.0.0 20150114 (Red Hat 5.0.0-0.1) -fpreprocessed -mtune=generic -march=x86-64 -g

It is wrong that gcc puts -fpreprocessed into DW_AT_producer - I may post a gcc
patch for it.  But even if it gets accepted there are already built inferiors
out there which GDB could be compatible (for the 'compile' mode) with.

gdb.compile/*.exp PASSes for it on {x86_64,x86_64-m32}-fedora22pre-linux-gnu.


Thanks,
Jan

gdb/ChangeLog
2015-01-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Filter out inferior gcc option -fpreprocessed.
	* compile/compile.c (filter_args): New function.
	(get_args): Use it.

diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index ccac49d..ecbd15c 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -324,6 +324,26 @@ get_selected_pc_producer_options (void)
   return cs;
 }
 
+/* Filter out unwanted options from *ARGCP and ARGV.  */
+
+static void
+filter_args (int *argcp, char **argv)
+{
+  char **destv;
+
+  for (destv = argv; *argv != NULL; argv++)
+    {
+      /* -fpreprocessed may get in commonly from ccache.  */
+      if (strcmp (*argv, "-fpreprocessed") == 0)
+	{
+	  (*argcp)--;
+	  continue;
+	}
+      *destv++ = *argv;
+    }
+  *destv = NULL;
+}
+
 /* Produce final vector of GCC compilation options.  First element is target
    size ("-m64", "-m32" etc.), optionally followed by DW_AT_producer options
    and then compile-args string GDB variable.  */
@@ -346,6 +366,7 @@ get_args (const struct compile_instance *compiler, struct gdbarch *gdbarch,
       char **argv_producer;
 
       build_argc_argv (cs_producer_options, &argc_producer, &argv_producer);
+      filter_args (&argc_producer, argv_producer);
       append_args (argcp, argvp, argc_producer, argv_producer);
       freeargv (argv_producer);
     }