[patch] Fix initial language with -readnow, regressed by: RFC: add DWARF index support

[Jan Kratochvil]

Hi,

if you use -readnow the common autodetection
	The current source language is "auto; currently c++".
fails
	The current source language is "auto; currently c".
causing various C++ handling problems.

dw2_find_symbol_file:
  /* index_table is NULL if OBJF_READNOW.  */
  if (!dwarf2_per_objfile->index_table)
    return NULL;

There are only 'skip'ped commits left to test.
The first bad commit could be any of:
28cfc710ba3d9959cedd0f345bb212666cc6890f
cf9fe5cf2be8b76820a05c966cdca6df5c2eee24
3363422556d95de01c4a262489fec8d6b5506d01
We cannot bisect more!
bisect run cannot continue any more

No regressions on {x86_64,x86_64-m32,i686}-fedora16pre-linux-gnu.
I will check it in.


Thanks,
Jan


gdb/
2011-09-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix initial language detection with -readnow.
	* symtab.c (find_main_filename): New variables sym and readnow_seen.
	Use them for lookup_symbol.

gdb/testsuite/
2011-09-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix initial language detection with -readnow.
	* gdb.cp/readnow-language.cc: New file.
	* gdb.cp/readnow-language.exp: New file.

--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -1687,17 +1687,30 @@ find_main_filename (void)
 {
   struct objfile *objfile;
   char *name = main_name ();
+  struct symbol *sym;
+  int readnow_seen = 0;
 
   ALL_OBJFILES (objfile)
   {
     const char *result;
 
+    readnow_seen |= (objfile->flags & OBJF_READNOW) != 0;
+
     if (!objfile->sf)
       continue;
     result = objfile->sf->qf->find_symbol_file (objfile, name);
     if (result)
       return result;
   }
+
+  /* OBJF_READNOW does not provide any index to look up above.  */
+  if (readnow_seen)
+    {
+      sym = lookup_symbol (name, NULL, VAR_DOMAIN, NULL);
+      if (sym)
+	return sym->symtab->filename;
+    }
+
   return (NULL);
 }
 
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/readnow-language.cc
@@ -0,0 +1,21 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2011 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+main ()
+{
+}
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/readnow-language.exp
@@ -0,0 +1,28 @@
+# Copyright 2011 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set testfile readnow-language
+set srcfile ${testfile}.cc
+set executable ${testfile}
+if {[build_executable ${testfile}.exp $executable ${testfile}.cc {c++ debug}] == -1} {
+    return -1
+}
+
+set old_gdbflags $GDBFLAGS
+set GDBFLAGS "$GDBFLAGS -readnow"
+clean_restart $executable
+set GDBFLAGS $old_gdbflags
+
+gdb_test "show language" {The current source language is "auto; currently c\+\+"\.}