gdb/python: new Progspace.executable_filename attribute

Add a new Progspace.executable_filename attribute that contains the
path to the executable for this program space, or None if no
executable is set.

The path within this attribute will be set by the "exec-file" and/or
"file" commands.

Accessing this attribute for an invalid program space will raise an
exception.

This new attribute is similar too, but not the same as the existing
gdb.Progspace.filename attribute.  If I could change the past, I'd
change the 'filename' attribute to 'symbol_filename', which is what it
actually represents.  The old attribute will be set by the
'symbol-file' command, while the new attribute is set by the
'exec-file' command.  Obviously the 'file' command sets both of these
attributes.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>

gdb/NEWS

@@ -303,6 +303,13 @@ show tui mouse-events
      Progspace.filename is not None), otherwise, this attribute is
      itself None.
 
+  ** New attribute Progspace.executable_filename.  This attribute
+     holds a string containing a file name set by the "exec-file" or
+     "file" commands, or None if no executable file is set.  This
+     isn't the exact string passed by the user to these commands; the
+     file name will have been partially resolved to an absolute file
+     name.
+
 *** Changes in GDB 13
 
 * MI version 1 is deprecated, and will be removed in GDB 14.

gdb/doc/python.texi

@@ -5095,6 +5095,21 @@ If the @code{Progspace} is invalid, i.e.@:, when
 access this attribute will raise a @code{RuntimeError} exception.
 @end defvar
 
+@defvar Progspace.executable_filename
+The file name, as a string, of the executable file in use by this
+program space.  The executable file is the file that @value{GDBN} will
+invoke in order to start an inferior when using a native target.  The
+file name within this attribute is updated by the @kbd{exec-file} and
+@kbd{file} commands.
+
+If no executable is currently set within this @code{Progspace} then
+this attribute contains @code{None}.
+
+If the @code{Progspace} is invalid, i.e.@:, when
+@code{Progspace.is_valid()} returns @code{False}, then attempting to
+access this attribute will raise a @code{RuntimeError} exception.
+@end defvar
+
 @defvar Progspace.pretty_printers
 The @code{pretty_printers} attribute is a list of functions.  It is
 used to look up pretty-printers.  A @code{Value} is passed to each

gdb/python/py-progspace.c

@@ -131,6 +131,25 @@ pspy_get_symbol_file (PyObject *self, void *closure)
   Py_RETURN_NONE;
 }
 
+/* Implement the gdb.Progspace.executable_filename attribute.  Retun a
+   string containing the name of the current executable, or None if no
+   executable is currently set.  If the Progspace is invalid then raise an
+   exception.  */
+
+static PyObject *
+pspy_get_exec_file (PyObject *self, void *closure)
+{
+  pspace_object *obj = (pspace_object *) self;
+
+  PSPY_REQUIRE_VALID (obj);
+
+  const char *filename = obj->pspace->exec_filename.get ();
+  if (filename != nullptr)
+    return host_string_to_python_string (filename).release ();
+
+  Py_RETURN_NONE;
+}
+
 static void
 pspy_dealloc (PyObject *self)
 {
@@ -596,6 +615,8 @@ static gdb_PyGetSetDef pspace_getset[] =
   { "symbol_file", pspy_get_symbol_file, nullptr,
     "The gdb.Objfile for the progspace's main symbol file, or None.",
     nullptr},
+  { "executable_filename", pspy_get_exec_file, nullptr,
+    "The filename for the progspace's executable, or None.", nullptr},
   { "pretty_printers", pspy_get_printers, pspy_set_printers,
     "Pretty printers.", NULL },
   { "frame_filters", pspy_get_frame_filters, pspy_set_frame_filters,

gdb/testsuite/gdb.python/py-exec-file.c

@@ -0,0 +1,22 @@
+/* This test program is part of GDB, the GNU debugger.
+
+   Copyright 2023 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 ()
+{
+  return 0;
+}

gdb/testsuite/gdb.python/py-exec-file.exp

@@ -0,0 +1,100 @@
+# Copyright (C) 2023 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/>.
+
+require allow_python_tests
+
+load_lib gdb-python.exp
+
+standard_testfile
+
+set binfile1 ${binfile}-a
+set binfile2 ${binfile}-b
+
+if {[build_executable "failed to prepare first executable" \
+	 $binfile1 $srcfile]} {
+    return -1
+}
+
+if {[build_executable "failed to prepare second executable" \
+	 $binfile2 $srcfile]} {
+    return -1
+}
+
+set binfile1 [gdb_remote_download host $binfile1]
+set binfile2 [gdb_remote_download host $binfile2]
+
+# Check that the executable_filename is set correctly after using the
+# 'file' command.
+with_test_prefix "using 'file' command" {
+    clean_restart
+
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"None" \
+	"check executable_filename when no file is loaded"
+
+    gdb_test "file $binfile1" \
+	"Reading symbols from [string_to_regexp $binfile1]\\.\\.\\..*" \
+	"load first executable"
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"[string_to_regexp $binfile1]" \
+	"check executable_filename when first executable is loaded"
+
+    gdb_test "file $binfile2" \
+	"Reading symbols from [string_to_regexp $binfile2]\\.\\.\\..*" \
+	"load second executable" \
+	"Load new symbol table from .*\? .y or n. " "y"
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"[string_to_regexp $binfile2]" \
+	"check executable_filename when second executable is loaded"
+
+    gdb_unload
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"None" \
+	"check executable_filename after unloading file"
+}
+
+# Check that the executable_filename is correctly set when we only set
+# the exec-file.
+with_test_prefix "using 'exec-file' command" {
+    clean_restart
+    gdb_test_no_output "exec-file $binfile1" \
+	"load first executable"
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"[string_to_regexp $binfile1]" \
+	"check executable_filename when first executable is loaded"
+
+    gdb_test_no_output "exec-file $binfile2" \
+	"load second executable"
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"[string_to_regexp $binfile2]" \
+	"check executable_filename when second executable is loaded"
+
+    gdb_test "exec-file" "No executable file now\\."
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"None" \
+	"check executable_filename after unloading file"
+}
+
+# Check that setting the symbol-file doesn't cause the
+# executable_filename to be set.
+with_test_prefix "using 'symbol-file' command" {
+    clean_restart
+    gdb_test "symbol-file $binfile1" \
+	"Reading symbols from [string_to_regexp $binfile1]\\.\\.\\..*" \
+	"load first executable"
+    gdb_test "python print(gdb.current_progspace().executable_filename)" \
+	"None" \
+	"check executable_filename after setting symbol-file"
+}