Ignore __fu<digits>__ symbols from COFF symbol tables

The debugger sometimes prints strange function names for given
addresses. For instance, with the following source code...

	4    procedure Foo is
	5       A : Integer;
	6    begin
	7       Do_Nothing (A'Address);
	8    end Foo;

... we can see...

    (gdb) info line 5
    Line 5 of "foo.adb" starts at address 0x4017ca <_ada_foo+6>
       and ends at 0x4017d2 <_fu29__system__scalar_values__is_is4+7>.
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

_fu29__system__scalar_values__is_is4 is an artificial symbol
generated by the linker, and interferes with the pc-to-symbol
resolution.  There isn't much in the general minimal_symbol
data that could help us identify them, so this patch changes
the COFF reader to simply ignore them.

gdb/ChangeLog:

	* coffread.c (is_import_fixup_symbol): New function.
	(record_minimal_symbol): Use is_import_fixup_symbol to
	detect import fixup symbols, and discard them.

gdb/testsuite/ChangeLog:

        * gdb.ada/win_fu_syms: New testcase.

4 files changed, 98 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.ada/win_fu_syms.exp b/gdb/testsuite/gdb.ada/win_fu_syms.exp
new file mode 100644
index 0000000..c3cbf16
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/win_fu_syms.exp
@@ -0,0 +1,35 @@
+# Copyright 2013 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/>.
+
+load_lib "ada.exp"
+
+standard_ada_testfile foo
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug additional_flags=-bargs additional_flags=-shared additional_flags=-margs]] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+set loc [gdb_get_line_number "Integer" ${testdir}/foo.adb]
+gdb_test "info line foo.adb:$loc" \
+         "Line $decimal of \".*foo\\.adb\" starts at address $hex <_ada_foo\\+$decimal> and ends at $hex <_ada_foo\\+$decimal>\\." \
+         "info line on variable declaration"
+
+set loc [gdb_get_line_number "Do_Nothing" ${testdir}/foo.adb]
+gdb_test "info line foo.adb:$loc" \
+         "Line $decimal of \".*foo\\.adb\" starts at address $hex <_ada_foo\\+$decimal> and ends at $hex <_ada_foo\\+$decimal>\\." \
+         "info line on Do_Nothing call"
+
diff --git a/gdb/testsuite/gdb.ada/win_fu_syms/foo.adb b/gdb/testsuite/gdb.ada/win_fu_syms/foo.adb
new file mode 100644
index 0000000..a09a346
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/win_fu_syms/foo.adb
@@ -0,0 +1,23 @@
+--  Copyright 2013 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/>.
+
+pragma Initialize_Scalars;
+with Pck; use Pck;
+
+procedure Foo is
+   A : Integer;
+begin
+   Do_Nothing (A'Address);
+end Foo;
diff --git a/gdb/testsuite/gdb.ada/win_fu_syms/pck.adb b/gdb/testsuite/gdb.ada/win_fu_syms/pck.adb
new file mode 100644
index 0000000..808da4db
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/win_fu_syms/pck.adb
@@ -0,0 +1,21 @@
+--  Copyright 2007-2013 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/>.
+
+package body Pck is
+   procedure Do_Nothing (A : System.Address) is
+   begin
+      null;
+   end Do_Nothing;
+end Pck;
diff --git a/gdb/testsuite/gdb.ada/win_fu_syms/pck.ads b/gdb/testsuite/gdb.ada/win_fu_syms/pck.ads
new file mode 100644
index 0000000..d5791b2
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/win_fu_syms/pck.ads
@@ -0,0 +1,19 @@
+--  Copyright 2007-2013 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/>.
+
+with System;
+package Pck is
+   procedure Do_Nothing (A : System.Address);
+end Pck;