Add global_context parameter to gdb.parse_and_eval

This adds a 'global_context' parse_and_eval to gdb.parse_and_eval.
This lets users request a parse that is done at "global scope".

I considered letting callers pass in a block instead, with None
meaning "global" -- but then there didn't seem to be a clean way to
express the default for this parameter.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>

gdb/NEWS

@@ -195,6 +195,10 @@ info main
   ** New function gdb.execute_mi(COMMAND, [ARG]...), that invokes a
      GDB/MI command and returns the output as a Python dictionary.
 
+  ** gdb.parse_and_eval now has a new "global_context" parameter.
+     This can be used to request that the parse only examine global
+     symbols.
+
 *** Changes in GDB 13
 
 * MI version 1 is deprecated, and will be removed in GDB 14.

gdb/doc/python.texi

@@ -419,11 +419,16 @@ using the @code{gdb.Value} constructor.
 @end defun
 
 @findex gdb.parse_and_eval
-@defun gdb.parse_and_eval (expression)
+@defun gdb.parse_and_eval (expression @r{[}, global_context@r{]})
 Parse @var{expression}, which must be a string, as an expression in
 the current language, evaluate it, and return the result as a
 @code{gdb.Value}.
 
+@var{global_context}, if provided, is a boolean indicating whether the
+parsing should be done in the global context.  The default is
+@samp{False}, meaning that the current frame or current static context
+should be used.
+
 This function can be useful when implementing a new command
 (@pxref{CLI Commands In Python}, @pxref{GDB/MI Commands In Python}),
 as it provides a way to parse the

gdb/python/python.c

@@ -969,19 +969,34 @@ gdbpy_decode_line (PyObject *self, PyObject *args)
 
 /* Parse a string and evaluate it as an expression.  */
 static PyObject *
-gdbpy_parse_and_eval (PyObject *self, PyObject *args)
+gdbpy_parse_and_eval (PyObject *self, PyObject *args, PyObject *kw)
 {
-  const char *expr_str;
+  static const char *keywords[] = { "expression", "global_context", nullptr };
 
-  if (!PyArg_ParseTuple (args, "s", &expr_str))
-    return NULL;
+  const char *expr_str;
+  PyObject *global_context_obj = nullptr;
+
+  if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|O!", keywords,
+					&expr_str,
+					&PyBool_Type, &global_context_obj))
+    return nullptr;
+
+  parser_flags flags = 0;
+  if (global_context_obj != NULL)
+    {
+      int cmp = PyObject_IsTrue (global_context_obj);
+      if (cmp < 0)
+	return nullptr;
+      if (cmp)
+	flags |= PARSER_LEAVE_BLOCK_ALONE;
+    }
 
   PyObject *result = nullptr;
   try
     {
       gdbpy_allow_threads allow_threads;
       scoped_value_mark free_values;
-      struct value *val = parse_and_eval (expr_str);
+      struct value *val = parse_and_eval (expr_str, flags);
       result = value_to_value_object (val);
     }
   catch (const gdb_exception &except)
@@ -2563,8 +2578,9 @@ The first element contains any unparsed portion of the String parameter\n\
 (or None if the string was fully parsed).  The second element contains\n\
 a tuple that contains all the locations that match, represented as\n\
 gdb.Symtab_and_line objects (or None)."},
-  { "parse_and_eval", gdbpy_parse_and_eval, METH_VARARGS,
-    "parse_and_eval (String) -> Value.\n\
+  { "parse_and_eval", (PyCFunction) gdbpy_parse_and_eval,
+    METH_VARARGS | METH_KEYWORDS,
+    "parse_and_eval (String, [Boolean]) -> Value.\n\
 Parse String as an expression, evaluate it, and return the result as a Value."
   },
 

gdb/testsuite/gdb.python/py-value.c

@@ -79,6 +79,8 @@ int func2 (int arg1, int arg2)
 
 char **save_argv;
 
+int shadowed = 23;
+
 int
 main (int argc, char *argv[])
 {
@@ -96,6 +98,7 @@ main (int argc, char *argv[])
   int i = 2;
   int *ptr_i = &i;
   struct str *xstr;
+  int shadowed = 97;
 
   /* Prevent gcc from optimizing argv[] out.  */
 

gdb/testsuite/gdb.python/py-value.exp

@@ -338,6 +338,11 @@ proc test_value_in_inferior {} {
   gdb_py_test_silent_cmd "python str = '\"str\"'" "set up str variable" 1
   gdb_test "python print (gdb.parse_and_eval (str).string (length = 10))" \
       "gdb.error: Attempt to take address of value not located in memory.\r\nError while executing Python code."
+
+  gdb_test "python print (gdb.parse_and_eval ('shadowed'))" \
+      97 "shadowed local value"
+  gdb_test "python print (gdb.parse_and_eval ('shadowed', global_context=True))" \
+      23 "shadowed global value"
 }
 
 proc test_inferior_function_call {} {