[python][patch] Add is_base_class attribute to fields.

[Phil Muldoon <pmuldoon at redhat dot com>]

This patch adds an "is_base_class" attribute to the fields function in 
the Python GDB type representation.

The original source of this patch was originally written and submitted 
to the archer project by Rich Ward.

http://sourceware.org/ml/archer/2009-q2/msg00176.html

Later I fixed a bug/added tests to capture a regression this 
functionality caused.

http://sourceware.org/ml/archer/2009-q4/msg00016.html?

Ok to commit?

Cheers,

Phil Muldoon

--

ChangeLog:

2009-11-30  Richard Ward  <richard.j.ward1@googlemail.com>

	* python/py-type.c (convert_field): New attribute "is_base_class".

doc/ChangeLog:

2009-11-30  Richard Ward  <richard.j.ward1@googlemail.com>

	* gdb.texinfo (Types In Python): Describe "is_base_class".

testsuite/ChangeLog:

2009-11-30  Phil Muldoon <pmuldoon@redhat.com>
	PR python/10805

	* gdb.python/py-type.exp: New file.
	* gdb.python/py-type.c: New file.
	* Makefile.in: Add py-type.

--

Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.644
diff -u -r1.644 gdb.texinfo
--- doc/gdb.texinfo	25 Nov 2009 20:43:29 -0000	1.644
+++ doc/gdb.texinfo	30 Nov 2009 10:16:50 -0000
@@ -19608,6 +19608,12 @@
 it was provided by the compiler and not the user.  This attribute is
 always provided, and is @code{False} if the field is not artificial.

+@item is_base_class
+This is @code{True} if the field represents a base class of a C@t{++}
+structure.  This attribute is always provided, and is @code{False}
+if the field is not a base class of the type on which @code{fields} was
+called, or if that type was not a C@t{++} class.
+
 @item bitsize
 If the field is packed, or is a bitfield, then this will have a
 non-zero value, which is the size of the field in bits.  Otherwise,
Index: python/py-type.c
===================================================================
RCS file: /cvs/src/src/gdb/python/py-type.c,v
retrieving revision 1.2
diff -u -r1.2 py-type.c
--- python/py-type.c	11 Sep 2009 18:51:31 -0000	1.2
+++ python/py-type.c	30 Nov 2009 10:16:51 -0000
@@ -169,6 +169,14 @@
   if (PyObject_SetAttrString (result, "artificial", arg) < 0)
     goto failarg;

+  if (TYPE_CODE (type) == TYPE_CODE_CLASS)
+    arg = field < TYPE_N_BASECLASSES (type) ? Py_True : Py_False;
+  else
+    arg = Py_False;
+  Py_INCREF (arg);
+  if (PyObject_SetAttrString (result, "is_base_class", arg) < 0)
+    goto failarg;
+
   arg = PyLong_FromLong (TYPE_FIELD_BITSIZE (type, field));
   if (!arg)
     goto fail;
Index: testsuite/gdb.python/Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.python/Makefile.in,v
retrieving revision 1.2
diff -u -r1.2 Makefile.in
--- testsuite/gdb.python/Makefile.in	9 Sep 2009 17:45:42 -0000	1.2
+++ testsuite/gdb.python/Makefile.in	30 Nov 2009 10:16:52 -0000
@@ -1,7 +1,7 @@
 VPATH = @srcdir@
 srcdir = @srcdir@

-EXECUTABLES = py-value py-prettyprint py-template
+EXECUTABLES = py-type py-value py-prettyprint py-template

 all info install-info dvi install uninstall installcheck check:
 	@echo "Nothing to be done for $@..."
Index: testsuite/gdb.python/py-type.c
===================================================================
RCS file: testsuite/gdb.python/py-type.c
diff -N testsuite/gdb.python/py-type.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.python/py-type.c	30 Nov 2009 10:16:52 -0000
@@ -0,0 +1,48 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 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/>.  */
+
+struct s
+{
+  int a;
+  int b;
+};
+
+#ifdef __cplusplus
+class C
+{
+ public:
+  int c;
+  int d;
+};
+#endif
+
+int
+main ()
+{
+  int ar[2] = {1,2};
+  struct s st;
+#ifdef __cplusplus
+  C c;
+  c.c = 1;
+  c.d = 2;
+#endif
+
+  st.a = 3;
+  st.b = 5;
+
+  return 0;      /* break to inspect struct and array.  */
+}
Index: testsuite/gdb.python/py-type.exp
===================================================================
RCS file: testsuite/gdb.python/py-type.exp
diff -N testsuite/gdb.python/py-type.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.python/py-type.exp	30 Nov 2009 10:16:52 -0000
@@ -0,0 +1,104 @@
+# Copyright (C) 2009 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/>.
+
+# This file is part of the GDB testsuite.  It tests the mechanism
+# of exposing types to Python.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile "py-type"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+# Build inferior to language specification.
+proc build_inferior {lang} {
+  global srcdir subdir srcfile binfile testfile hex
+
+  if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" 
executable "debug $lang"] != "" } {
+      untested "Couldn't compile ${srcfile} in $lang mode"
+      return -1
+  }
+}
+
+# Restart GDB, set breakpoint and run to that breakpoint.
+proc restart_gdb {bp} {
+  global srcdir subdir srcfile binfile testfile hex
+
+  gdb_exit
+  gdb_start
+  gdb_reinitialize_dir $srcdir/$subdir
+  gdb_load ${binfile}
+
+  if ![runto_main ] then {
+      perror "couldn't run to breakpoint"
+      return
+  }
+
+  gdb_breakpoint [gdb_get_line_number $bp]
+  gdb_continue_to_breakpoint $bp
+}
+
+
+# Run a command in GDB, and report a failure if a Python exception is 
thrown.
+# If report_pass is true, report a pass if no exception is thrown.
+proc gdb_py_test_silent_cmd {cmd name report_pass} {
+  global gdb_prompt
+
+  gdb_test_multiple $cmd $name {
+      -re "Traceback.*$gdb_prompt $"  { fail $name }
+      -re "$gdb_prompt $"	      { if $report_pass { pass $name } }
+  }
+}
+
+proc test_fields {lang} {
+  global gdb_prompt
+
+  if {$lang == "c++"} {
+      # Test usage with a class
+      gdb_py_test_silent_cmd "print c" "print value" 1
+      gdb_py_test_silent_cmd "python c = gdb.history (0)" "get value 
from history" 1
+      gdb_py_test_silent_cmd "python fields = c.type.fields()" "get 
fields" 1
+      gdb_test "python print len(fields)" "2" "Check number of fields"
+      gdb_test "python print fields\[0\].name" "c" "Check class field c 
name"
+      gdb_test "python print fields\[1\].name" "d" "Check class field d 
name"
+  }
+
+  # Test normal fields usage in structs.
+  gdb_py_test_silent_cmd "print st" "print value" 1
+  gdb_py_test_silent_cmd "python st = gdb.history (0)" "get value from 
history" 1
+  gdb_py_test_silent_cmd "python fields = st.type.fields()" "get fields" 1
+  gdb_test "python print len(fields)" "2" "Check number of fields"
+  gdb_test "python print fields\[0\].name" "a" "Check structure field a 
name"
+  gdb_test "python print fields\[1\].name" "b" "Check structure field b 
name"
+
+  # Test regression PR python/10805
+  gdb_py_test_silent_cmd "print ar" "print value" 1
+  gdb_py_test_silent_cmd "python ar = gdb.history (0)" "get value from 
 history" 1
+  gdb_test "python fields = ar.type.fields()"
+  gdb_test "python print len(fields)" "1" "Check the number of fields"
+  gdb_test "python print fields\[0\].type" "<range type>" "Check array 
field type"
+}
+
+# Perform C Tests.
+build_inferior "c"
+restart_gdb "break to inspect struct and array."
+test_fields "c"
+
+# Perform C++ Tests.
+build_inferior "c++"
+restart_gdb "break to inspect struct and array."
+test_fields "c++"