Add gdb.current_language and gdb.Frame.language

This adds the gdb.current_language function, which can be used to find
the current language without (1) ever having the value "auto" or (2)
having to parse the output of "show language".

It also adds the gdb.Frame.language, which can be used to find the
language of a given frame.  This is normally preferable if one has a
Frame object handy.

gdb/NEWS

@@ -58,6 +58,13 @@ maintenance info line-table
      This is the same format that GDB uses when printing address, symbol,
      and offset information from the disassembler.
 
+  ** New function gdb.current_language that returns the name of the
+     current language.  Unlike gdb.parameter('language'), this will
+     never return 'auto'.
+
+  ** New method gdb.Frame.language that returns the name of the
+     frame's language.
+
 *** Changes in GDB 12
 
 * DBX mode is deprecated, and will be removed in GDB 13

gdb/doc/python.texi

@@ -668,6 +668,14 @@ Here are some examples of the possible string formats:
 @end smallexample
 @end defun
 
+@defun gdb.current_language ()
+Return the name of the current language as a string.  Unlike
+@code{gdb.parameter('language')}, this function will never return
+@samp{auto}.  If a @code{gdb.Frame} object is available (@pxref{Frames
+In Python}), the @code{language} method might be preferable in some
+cases, as that is not affected by the user's language setting.
+@end defun
+
 @node Exception Handling
 @subsubsection Exception Handling
 @cindex python exceptions
@@ -5202,6 +5210,10 @@ Stack}.
 Return an integer, the stack frame level for this frame.  @xref{Frames, ,Stack Frames}.
 @end defun
 
+@defun Frame.language ()
+Return a string, the source language for this frame.
+@end defun
+
 @node Blocks In Python
 @subsubsection Accessing blocks from Python
 

gdb/python/py-frame.c

@@ -598,6 +598,29 @@ frapy_level (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* The language for this frame.  */
+
+static PyObject *
+frapy_language (PyObject *self, PyObject *args)
+{
+  try
+    {
+      struct frame_info *fi;
+      FRAPY_REQUIRE_VALID (self, fi);
+
+      enum language lang = get_frame_language (fi);
+      const language_defn *lang_def = language_def (lang);
+
+      return host_string_to_python_string (lang_def->name ()).release ();
+    }
+  catch (const gdb_exception &except)
+    {
+      GDB_PY_HANDLE_EXCEPTION (except);
+    }
+
+  Py_RETURN_NONE;
+}
+
 /* Implementation of gdb.newest_frame () -> gdb.Frame.
    Returns the newest frame object.  */
 
@@ -771,6 +794,8 @@ Return the value of the variable in this frame." },
     "Select this frame as the user's current frame." },
   { "level", frapy_level, METH_NOARGS,
     "The stack level of this frame." },
+  { "language", frapy_language, METH_NOARGS,
+    "The language of this frame." },
   {NULL}  /* Sentinel */
 };
 

gdb/python/python.c

@@ -1571,6 +1571,14 @@ gdbpy_progspaces (PyObject *unused1, PyObject *unused2)
   return list.release ();
 }
 
+/* Return the name of the current language.  */
+
+static PyObject *
+gdbpy_current_language (PyObject *unused1, PyObject *unused2)
+{
+  return host_string_to_python_string (current_language->name ()).release ();
+}
+
 
 
 /* The "current" objfile.  This is set when gdb detects that a new
@@ -2534,6 +2542,10 @@ Format ADDRESS, an address within PROG_SPACE, a gdb.Progspace, using\n\
 ARCH, a gdb.Architecture to determine the address size.  The format of\n\
 the returned string is 'ADDRESS <SYMBOL+OFFSET>' without the quotes." },
 
+  { "current_language", gdbpy_current_language, METH_NOARGS,
+    "current_language () -> string\n\
+Return the name of the currently selected language." },
+
   {NULL, NULL, 0, NULL}
 };
 

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

@@ -128,3 +128,9 @@ if { $pc != "" } {
 	" = True" \
 	"test Frame.read_register($pc)"
 }
+
+# Test language.
+gdb_test "python print(gdb.selected_frame().language())" "c"
+gdb_test "set language ada"
+gdb_test "python print(gdb.selected_frame().language())" "c" \
+    "frame language is not affected by global language"

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

@@ -370,6 +370,19 @@ proc_with_prefix test_throwing_parameter { } {
 	"gdb.GdbError does not show Python stack"
 }
 
+proc_with_prefix test_language {} {
+    gdb_test "python print(gdb.parameter('language'))" "auto" \
+	"print language parameter"
+    gdb_test "python print(gdb.current_language())" "c" \
+	"print current language"
+    gdb_test_no_output "set lang rust"
+    gdb_test "python print(gdb.parameter('language'))" "rust" \
+	"print language parameter for rust"
+    gdb_test "python print(gdb.current_language())" "rust" \
+	"print current language for rust"
+    gdb_test_no_output "set lang auto"
+}
+
 test_directories
 test_data_directory
 test_boolean_parameter
@@ -380,6 +393,7 @@ test_really_undocumented_parameter
 test_deprecated_api_parameter
 test_integer_parameter
 test_throwing_parameter
+test_language
 
 # This caused a gdb crash.
 gdb_test "python print(gdb.parameter('endian'))" "auto" \

gdb/testsuite/gdb.rust/pp.exp

@@ -40,3 +40,5 @@ if {![runto ${srcfile}:$line]} {
 
 gdb_test "print outer" " = pp::Outer \\(x\\(5\\)\\)"
 gdb_test "print outer.0" " = x\\(5\\)"
+
+gdb_test "python print(gdb.selected_frame().language())" "rust"