2008-10-16 Thiago Jung Bauermann <bauerman@br.ibm.com>

	    Tom Tromey  <tromey@redhat.com>

gdb/
	* Makefile.in (SUBDIR_PYTHON_OBS): Add python-value.o.
	(SUBDIR_PYTHON_SRCS): Add python-value.c.
	(python-value.o): New target.
	* configure.ac (CONFIG_OBS): Add python-value.o.
	(CONFIG_SRCS): Add python/python-value.c
	* configure: Regenerate.
	* python-internal.h (value_object_type): Add external declaration.
	(gdbpy_get_value_from_history, value_to_value_object,
	convert_value_from_python, gdbpy_initialize_values): Add function
	prototype.
	* python/python-value.c: New file.
	* python/python.c (GdbMethods): Add gdbpy_get_value_from_history.
	(_initialize_python): Call gdbpy_initialize_values.
	* python/python.h (values_in_python): Add external declaration.
	* value.c (value_prepend_to_list, value_remove_from_list): New
	functions.
	(preserve_values): Iterate over values_in_python list as well.
	* value.h (value_prepend_to_list, value_remove_from_list): Add
	function prototypes.

gdb/doc/
	* gdb.texinfo. (Values From Inferior): New subsubsection.

gdb/testsuite/
	* gdb.python/python-value.c: New file.
	* gdb.python/python-value.exp: New file.

13 files changed, 430 insertions, 15 deletions

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 5b6c93d..93f9d94 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -271,10 +271,12 @@ SUBDIR_TUI_CFLAGS= \
 #
 SUBDIR_PYTHON_OBS = \
 	python.o \
-	python-utils.o
+	python-utils.o \
+	python-value.o
 SUBDIR_PYTHON_SRCS = \
 	python/python.c \
-	python/python-utils.c
+	python/python-utils.c \
+	python/python-value.c
 SUBDIR_PYTHON_DEPS =
 SUBDIR_PYTHON_LDFLAGS=
 SUBDIR_PYTHON_CFLAGS=
@@ -1836,6 +1838,10 @@ python-utils.o: $(srcdir)/python/python-utils.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/python-utils.c
 	$(POSTCOMPILE)
 
+python-value.o: $(srcdir)/python/python-value.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/python-value.c
+	$(POSTCOMPILE)
+
 #
 # Dependency tracking.  Most of this is conditional on GNU Make being
 # found by configure; if GNU Make is not found, we fall back to a
diff --git a/gdb/configure b/gdb/configure
index 7955569..7f4d2a6 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -11704,10 +11704,10 @@ rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
 echo "${ECHO_T}${PYTHON_CFLAGS}" >&6
   fi
 else
-  # Even if Python support is not compiled in, we need to have this file
+  # Even if Python support is not compiled in, we need to have these files
   # included in order to recognize the GDB command "python".
-  CONFIG_OBS="$CONFIG_OBS python.o"
-  CONFIG_SRCS="$CONFIG_SRCS python/python.c"
+  CONFIG_OBS="$CONFIG_OBS python.o python-value.o"
+  CONFIG_SRCS="$CONFIG_SRCS python/python.c python/python-value.c"
 fi
 
 
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 680fba0..677a6ae 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -624,10 +624,10 @@ if test "${have_libpython}" = yes; then
     AC_MSG_RESULT(${PYTHON_CFLAGS})
   fi
 else
-  # Even if Python support is not compiled in, we need to have this file
+  # Even if Python support is not compiled in, we need to have these files
   # included in order to recognize the GDB command "python".
-  CONFIG_OBS="$CONFIG_OBS python.o"
-  CONFIG_SRCS="$CONFIG_SRCS python/python.c"
+  CONFIG_OBS="$CONFIG_OBS python.o python-value.o"
+  CONFIG_SRCS="$CONFIG_SRCS python/python.c python/python-value.c"
 fi
 AC_SUBST(PYTHON_CFLAGS)
 
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 314a6f0..c784c29 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2008-10-16  Thiago Jung Bauermann  <bauerman@br.ibm.com>
+
+	* gdb.texinfo. (Values From Inferior): New subsubsection.
+
 2008-10-06  Doug Evans  <dje@google.com>
 
 	* gdb.texinfo (set debug dwarf2-die): Document it.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 67b5fac..d150466 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -17690,6 +17690,7 @@ situation, a Python @code{KeyboardInterrupt} exception is thrown.
 @menu
 * Basic Python::                Basic Python Functions.
 * Exception Handling::
+* Values From Inferior::
 @end menu
 
 @node Basic Python
@@ -17768,6 +17769,64 @@ message as its value, and the Python call stack backtrace at the
 Python statement closest to where the @value{GDBN} error occured as the
 traceback.
 
+@node Values From Inferior
+@subsubsection Values From Inferior
+@cindex values from inferior, with Python
+@cindex python, working with values from inferior
+
+@cindex @code{gdb.Value}
+@value{GDBN} provides values it obtains from the inferior program in
+an object of type @code{gdb.Value}.  @value{GDBN} uses this object
+for its internal bookkeeping of the inferior's values, and for
+fetching values when necessary.
+
+Inferior values that are simple scalars can be used directly in
+Python expressions that are valid for the value's data type.  Here's
+an example for an integer or floating-point value @code{some_val}:
+
+@smallexample
+bar = some_val + 2
+@end smallexample
+
+@noindent
+As result of this, @code{bar} will also be a @code{gdb.Value} object
+whose values are of the same type as those of @code{some_val}.
+
+Inferior values that are structures or instances of some class can
+be accessed using the Python @dfn{dictionary syntax}.  For example, if
+@code{some_val} is a @code{gdb.Value} instance holding a structure, you
+can access its @code{foo} element with:
+
+@smallexample
+bar = some_val['foo']
+@end smallexample
+
+Again, @code{bar} will also be a @code{gdb.Value} object.
+
+For pointer data types, @code{gdb.Value} provides a method for
+dereferencing the pointer to obtain the object it points to.
+
+@defmethod Value dereference
+This method returns a new @code{gdb.Value} object whose contents is
+the object pointed to by the pointer.  For example, if @code{foo} is
+a C pointer to an @code{int}, declared in your C program as
+
+@smallexample
+int *foo;
+@end smallexample
+
+@noindent
+then you can use the corresponding @code{gdb.Value} to access what
+@code{foo} points to like this:
+
+@smallexample
+bar = foo.dereference ()
+@end smallexample
+
+The result @code{bar} will be a @code{gdb.Value} object holding the
+value pointed to by @code{foo}.
+@end defmethod
+
 @node Interpreters
 @chapter Command Interpreters
 @cindex command interpreters
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index f850448..72f7a5f 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -43,11 +43,18 @@ typedef Py_intptr_t Py_ssize_t;
 #error "Unable to find usable Python.h"
 #endif
 
-struct block;
-struct symbol;
-struct symtab_and_line;
+struct value;
 
 extern PyObject *gdb_module;
+extern PyTypeObject value_object_type;
+
+PyObject *gdbpy_get_value_from_history (PyObject *self, PyObject *args);
+
+PyObject *value_to_value_object (struct value *v);
+
+struct value *convert_value_from_python (PyObject *obj);
+
+void gdbpy_initialize_values (void);
 
 struct cleanup *make_cleanup_py_decref (PyObject *py);
 
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 8bc24c2..77d8774 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -52,6 +52,8 @@ static PyObject *gdbpy_flush (PyObject *, PyObject *);
 
 static PyMethodDef GdbMethods[] =
 {
+  { "get_value_from_history", gdbpy_get_value_from_history, METH_VARARGS,
+    "Get a value from history" },
   { "execute", execute_gdb_command, METH_VARARGS,
     "Execute a gdb command" },
   { "get_parameter", get_parameter, METH_VARARGS,
@@ -398,6 +400,8 @@ Enables or disables printing of Python stack traces."),
   PyModule_AddStringConstant (gdb_module, "HOST_CONFIG", (char*) host_name);
   PyModule_AddStringConstant (gdb_module, "TARGET_CONFIG", (char*) target_name);
 
+  gdbpy_initialize_values ();
+
   PyRun_SimpleString ("import gdb");
 
   /* Create a couple objects which are used for Python's stdout and
diff --git a/gdb/python/python.h b/gdb/python/python.h
index 00ff159..102fef6 100644
--- a/gdb/python/python.h
+++ b/gdb/python/python.h
@@ -22,6 +22,8 @@
 
 #include "value.h"
 
+extern struct value *values_in_python;
+
 void eval_python_from_control_command (struct command_line *);
 
 #endif /* GDB_PYTHON_H */
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 1dd8d4b..7f50bed 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-10-16  Thiago Jung Bauermann  <bauerman@br.ibm.com>
+
+	* gdb.python/python-value.c: New file.
+	* gdb.python/python-value.exp: New file.
+
 2008-10-15  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdb.mi/mi-nsmoribund.exp, gdb.mi/nsmoribund.c: New test.
diff --git a/gdb/testsuite/gdb.python/python-value.c b/gdb/testsuite/gdb.python/python-value.c
new file mode 100644
index 0000000..82cfd9a
--- /dev/null
+++ b/gdb/testsuite/gdb.python/python-value.c
@@ -0,0 +1,41 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2008 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;
+};
+
+union u
+{
+  int a;
+  float b;
+};
+
+int
+main (int argc, char *argv[])
+{
+  struct s s;
+  union u u;
+
+  s.a = 3;
+  s.b = 5;
+  u.a = 7;
+
+  return 0;      /* break to inspect struct and union */
+}
diff --git a/gdb/testsuite/gdb.python/python-value.exp b/gdb/testsuite/gdb.python/python-value.exp
new file mode 100644
index 0000000..7515ab7
--- /dev/null
+++ b/gdb/testsuite/gdb.python/python-value.exp
@@ -0,0 +1,250 @@
+# Copyright (C) 2008 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
+# exposing values to Python.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile "python-value"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile ${srcfile}"
+    return -1
+}
+
+# Usage: gdb_py_test_multiple NAME INPUT RESULT {INPUT RESULT}...
+# Run a test named NAME, consisting of multiple lines of input.
+# After each input line INPUT, search for result line RESULT.
+# Succeed if all results are seen; fail otherwise.
+proc gdb_py_test_multiple {name args} {
+    global gdb_prompt
+    foreach {input result} $args {
+	if {[gdb_test_multiple $input "$name - $input" {
+	    -re "\[\r\n\]*($result)\[\r\n\]+($gdb_prompt | *>)$" {
+		pass "$name - $input"
+	    }
+	}]} {
+	    return 1
+	}
+    }
+    return 0
+}
+
+# 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_value_creation {} {
+  global gdb_prompt
+
+  gdb_py_test_silent_cmd "python i = gdb.Value (True)" "create boolean value" 1
+  gdb_py_test_silent_cmd "python i = gdb.Value (5)" "create integer value" 1
+  gdb_py_test_silent_cmd "python i = gdb.Value (5L)" "create long value" 1
+  gdb_py_test_silent_cmd "python f = gdb.Value (1.25)" "create double value" 1
+  gdb_py_test_silent_cmd "python a = gdb.Value ('string test')" "create 8-bit string value" 1
+  gdb_test "python print a" "\"string test\"" "print 8-bit string"
+  gdb_test "python print a.__class__" "<type 'gdb.Value'>" "verify type of 8-bit string"
+  gdb_py_test_silent_cmd "python a = gdb.Value (u'unicode test')" "create unicode value" 1
+  gdb_test "python print a" "\"unicode test\"" "print Unicode string"
+  gdb_test "python print a.__class__" "<type 'gdb.Value'>" "verify type of unicode string"
+}
+
+proc test_value_numeric_ops {} {
+  global gdb_prompt
+
+  gdb_py_test_silent_cmd "python i = gdb.Value (5)" "create first integer value" 0
+  gdb_py_test_silent_cmd "python j = gdb.Value (2)" "create second integer value" 0
+  gdb_py_test_silent_cmd "python f = gdb.Value (1.25)" "create first double value" 0
+  gdb_py_test_silent_cmd "python g = gdb.Value (2.5)" "create second double value" 0
+  gdb_test "python print 'result = ' + str(i+j)" " = 7" "add two integer values"
+  gdb_test "python print (i+j).__class__" "<type 'gdb.Value'>" "verify type of integer add result"
+
+  gdb_test "python print 'result = ' + str(f+g)" " = 3.75" "add two double values"
+  gdb_test "python print 'result = ' + str(i-j)" " = 3" "subtract two integer values"
+  gdb_test "python print 'result = ' + str(f-g)" " = -1.25" "subtract two double values"
+  gdb_test "python print 'result = ' + str(i*j)" " = 10" "multiply two integer values"
+  gdb_test "python print 'result = ' + str(f*g)" " = 3.125" "multiply two double values"
+  gdb_test "python print 'result = ' + str(i/j)" " = 2" "divide two integer values"
+  gdb_test "python print 'result = ' + str(f/g)" " = 0.5" "divide two double values"
+  gdb_test "python print 'result = ' + str(i%j)" " = 1" "take remainder of two integer values"
+  # Remainder of float is implemented in Python but not in GDB's value system.
+
+  gdb_test "python print 'result = ' + str(i**j)" " = 25" "integer value raised to the power of another integer value"
+  gdb_test "python print 'result = ' + str(g**j)" " = 6.25" "double value raised to the power of integer value"
+
+  gdb_test "python print 'result = ' + str(-i)" " = -5" "negated integer value"
+  gdb_test "python print 'result = ' + str(+i)" " = 5" "positive integer value"
+  gdb_test "python print 'result = ' + str(-f)" " = -1.25" "negated double value"
+  gdb_test "python print 'result = ' + str(+f)" " = 1.25" "positive double value"
+  gdb_test "python print 'result = ' + str(abs(j-i))" " = 3" "absolute of integer value"
+  gdb_test "python print 'result = ' + str(abs(f-g))" " = 1.25" "absolute of double value"
+
+  # Test gdb.Value mixed with Python types.
+
+  gdb_test "python print 'result = ' + str(i-1)" " = 4" "subtract integer value from python integer"
+  gdb_test "python print (i-1).__class__" "<type 'gdb.Value'>" "verify type of mixed integer subtraction result"
+  gdb_test "python print 'result = ' + str(f+1.5)" " = 2.75" "add double value with python float"
+
+  gdb_test "python print 'result = ' + str(1-i)" " = -4" "subtract python integer from integer value"
+  gdb_test "python print 'result = ' + str(1.5+f)" " = 2.75" "add python float with double value"
+
+  # Test pointer arithmethic
+
+  # First, obtain the pointers
+  gdb_test "print (void *) 2" "" ""
+  gdb_test "python a = gdb.get_value_from_history (0)" "" ""
+  gdb_test "print (void *) 5" "" ""
+  gdb_test "python b = gdb.get_value_from_history (0)" "" ""
+
+  gdb_test "python print 'result = ' + str(a+5)" " = 0x7" "add pointer value with python integer"
+  gdb_test "python print 'result = ' + str(b-2)" " = 0x3" "subtract python integer from pointer value"
+  gdb_test "python print 'result = ' + str(b-a)" " = 3" "subtract two pointer values"
+
+  # Test some invalid operations.
+
+  gdb_test_multiple "python print 'result = ' + str(i+'foo')" "catch error in python type conversion" {
+      -re "Argument to arithmetic operation not a number or boolean.*$gdb_prompt $"   {pass "catch error in python type conversion"}
+      -re "result = .*$gdb_prompt $"		      {fail "catch error in python type conversion"}
+      -re "$gdb_prompt $"			      {fail "catch error in python type conversion"}
+  }
+
+  gdb_test_multiple "python print 'result = ' + str(i+gdb.Value('foo'))" "catch throw of GDB error" {
+      -re "Traceback.*$gdb_prompt $"  {pass "catch throw of GDB error"}
+      -re "result = .*$gdb_prompt $"  {fail "catch throw of GDB error"}
+      -re "$gdb_prompt $"	      {fail "catch throw of GDB error"}
+  }
+}
+
+proc test_value_boolean {} {
+  # First, define a useful function to test booleans.
+  gdb_py_test_multiple "define function to test booleans" \
+    "python" "" \
+    "def test_bool (val):" "" \
+    "  if val:" "" \
+    "    print 'yay'" "" \
+    "  else:" "" \
+    "    print 'nay'" "" \
+    "end" ""
+
+  gdb_test "py test_bool (gdb.Value (True))" "yay" "check evaluation of true boolean value in expression"
+
+  gdb_test "py test_bool (gdb.Value (False))" "nay" "check evaluation of false boolean value in expression"
+
+  gdb_test "py test_bool (gdb.Value (5))" "yay" "check evaluation of true integer value in expression"
+
+  gdb_test "py test_bool (gdb.Value (0))" "nay" "check evaluation of false integer value in expression"
+
+  gdb_test "py test_bool (gdb.Value (5.2))" "yay" "check evaluation of true integer value in expression"
+
+  gdb_test "py test_bool (gdb.Value (0.0))" "nay" "check evaluation of false integer value in expression"
+}
+
+proc test_value_compare {} {
+  gdb_test "py print gdb.Value (1) < gdb.Value (1)" "False" "less than, equal"
+  gdb_test "py print gdb.Value (1) < gdb.Value (2)" "True" "less than, less"
+  gdb_test "py print gdb.Value (2) < gdb.Value (1)" "False" "less than, greater"
+  gdb_test "py print gdb.Value (2) < None" "False" "less than, None"
+
+  gdb_test "py print gdb.Value (1) <= gdb.Value (1)" "True" "less or equal, equal"
+  gdb_test "py print gdb.Value (1) <= gdb.Value (2)" "True" "less or equal, less"
+  gdb_test "py print gdb.Value (2) <= gdb.Value (1)" "False" "less or equal, greater"
+  gdb_test "py print gdb.Value (2) <= None" "False" "less or equal, None"
+
+  gdb_test "py print gdb.Value (1) == gdb.Value (1)" "True" "equality of gdb.Values"
+  gdb_test "py print gdb.Value (1) == gdb.Value (2)" "False" "inequality of gdb.Values"
+  gdb_test "py print gdb.Value (1) == 1.0" "True" "equality of gdb.Value with Python value"
+  gdb_test "py print gdb.Value (1) == 2" "False" "inequality of gdb.Value with Python value"
+  gdb_test "py print gdb.Value (1) == None" "False" "inequality of gdb.Value with None"
+
+  gdb_test "py print gdb.Value (1) != gdb.Value (1)" "False" "inequality, false"
+  gdb_test "py print gdb.Value (1) != gdb.Value (2)" "True" "inequality, true"
+  gdb_test "py print gdb.Value (1) != None" "True" "inequality, None"
+
+  gdb_test "py print gdb.Value (1) > gdb.Value (1)" "False" "greater than, equal"
+  gdb_test "py print gdb.Value (1) > gdb.Value (2)" "False" "greater than, less"
+  gdb_test "py print gdb.Value (2) > gdb.Value (1)" "True" "greater than, greater"
+  gdb_test "py print gdb.Value (2) > None" "True" "greater than, None"
+
+  gdb_test "py print gdb.Value (1) >= gdb.Value (1)" "True" "greater or equal, equal"
+  gdb_test "py print gdb.Value (1) >= gdb.Value (2)" "False" "greater or equal, less"
+  gdb_test "py print gdb.Value (2) >= gdb.Value (1)" "True" "greater or equal, greater"
+  gdb_test "py print gdb.Value (2) >= None" "True" "greater or equal, None"
+}
+
+proc test_value_in_inferior {} {
+  global gdb_prompt
+  global testfile
+
+  gdb_breakpoint [gdb_get_line_number "break to inspect struct and union"]
+  gdb_start_cmd
+
+  # Avoid race condition where a continue command in gdb_continue_to_breakpoint
+  # is issued too early.
+  gdb_test "" "$gdb_prompt"
+
+  gdb_continue_to_breakpoint "break to inspect struct and union"
+
+  # Just get inferior variable s in the value history, available to python.
+  gdb_test "print s" " = {a = 3, b = 5}" ""
+
+  gdb_py_test_silent_cmd "python s = gdb.get_value_from_history (0)" "get value from history" 1
+
+  gdb_test "python print 'result = ' + str(s\['a'\])" " = 3" "access element inside struct using 8-bit string name"
+  gdb_test "python print 'result = ' + str(s\[u'a'\])" " = 3" "access element inside struct using unicode name"
+
+  # Test dereferencing the argv pointer
+
+  # Just get inferior variable argv the value history, available to python.
+  gdb_test "print argv" " = \\(char \\*\\*\\) 0x.*" ""
+
+  gdb_py_test_silent_cmd "python argv = gdb.get_value_from_history (0)" "" 0
+  gdb_py_test_silent_cmd "python arg0 = argv.dereference ()" "dereference value" 1
+
+  # Check that the dereferenced value is sane
+  gdb_test "python print arg0" "0x.*$testfile\"" "verify dereferenced value"
+}
+
+
+# Start with a fresh gdb.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test_multiple "python print 'hello, world!'" "verify python support" {
+    -re "not supported.*$gdb_prompt $"	{
+      unsupported "python support is disabled"
+      return -1
+    }
+    -re "$gdb_prompt $"	{}
+}
+
+test_value_creation
+test_value_numeric_ops
+test_value_boolean
+test_value_compare
+test_value_in_inferior
diff --git a/gdb/value.c b/gdb/value.c
index 06b0d1e..0b530f0 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -37,6 +37,8 @@
 #include "dfp.h"
 #include "objfiles.h"
 
+#include "python/python.h"
+
 /* Prototypes for exported functions. */
 
 void _initialize_values (void);
@@ -130,8 +132,8 @@ struct value
 
   /* Values are stored in a chain, so that they can be deleted easily
      over calls to the inferior.  Values assigned to internal
-     variables or put into the value history are taken off this
-     list.  */
+     variables, put into the value history or exposed to Python are
+     taken off this list.  */
   struct value *next;
 
   /* Register number if the value is from a register.  */
@@ -257,6 +259,31 @@ allocate_repeat_value (struct type *type, int count)
 					    type, range_type));
 }
 
+/* Needed if another module needs to maintain its on list of values.  */
+void
+value_prepend_to_list (struct value **head, struct value *val)
+{
+  val->next = *head;
+  *head = val;
+}
+
+/* Needed if another module needs to maintain its on list of values.  */
+void
+value_remove_from_list (struct value **head, struct value *val)
+{
+  struct value *prev;
+
+  if (*head == val)
+    *head = (*head)->next;
+  else
+    for (prev = *head; prev->next; prev = prev->next)
+      if (prev->next == val)
+      {
+	prev->next = val->next;
+	break;
+      }
+}
+
 /* Accessor methods.  */
 
 struct value *
@@ -916,6 +943,7 @@ preserve_values (struct objfile *objfile)
   htab_t copied_types;
   struct value_history_chunk *cur;
   struct internalvar *var;
+  struct value *val;
   int i;
 
   /* Create the hash table.  We allocate on the objfile's obstack, since
@@ -930,6 +958,9 @@ preserve_values (struct objfile *objfile)
   for (var = internalvars; var; var = var->next)
     preserve_one_value (var->value, objfile, copied_types);
 
+  for (val = values_in_python; val; val = val->next)
+    preserve_one_value (val, objfile, copied_types);
+
   htab_delete (copied_types);
 }
 
diff --git a/gdb/value.h b/gdb/value.h
index deb2629..f53d333 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -40,9 +40,15 @@ struct language_defn;
 
 struct value;
 
+/* Needed if another module needs to maintain its own list of values.  */
+
+void value_prepend_to_list (struct value **head, struct value *val);
+void value_remove_from_list (struct value **head, struct value *val);
+
 /* Values are stored in a chain, so that they can be deleted easily
-   over calls to the inferior.  Values assigned to internal variables
-   or put into the value history are taken off this list.  */
+   over calls to the inferior.  Values assigned to internal variables,
+   put into the value history or exposed to Python are taken off this
+   list.  */
 
 struct value *value_next (struct value *);