[binutils-gdb] Add gdb.current_language and gdb.Frame.language

[binutils-gdb] Add gdb.current_language and gdb.Frame.language

[Tom Tromey]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=80fa4b2a606763e71c4b599fa88288f554a0ea5b

commit 80fa4b2a606763e71c4b599fa88288f554a0ea5b
Author: Tom Tromey <tromey@adacore.com>
Date:   Tue May 24 10:15:17 2022 -0600

    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.

Diff:
---
 gdb/NEWS                                  |  7 +++++++
 gdb/doc/python.texi                       | 12 ++++++++++++
 gdb/python/py-frame.c                     | 25 +++++++++++++++++++++++++
 gdb/python/python.c                       | 12 ++++++++++++
 gdb/testsuite/gdb.python/py-frame.exp     |  6 ++++++
 gdb/testsuite/gdb.python/py-parameter.exp | 14 ++++++++++++++
 gdb/testsuite/gdb.rust/pp.exp             |  2 ++
 7 files changed, 78 insertions(+)

diff --git a/gdb/NEWS b/gdb/NEWS
index dac6dabfa42..960f90b4387 100644
--- a/gdb/NEWS
+++ b/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
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index f933c7d30c9..ba5a9b315e1 100644
--- a/gdb/doc/python.texi
+++ b/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
 
diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index 769e28c1a2c..9a28c36c1cc 100644
--- a/gdb/python/py-frame.c
+++ b/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 */
 };
 
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 11aaa7ae778..9bef2252e88 100644
--- a/gdb/python/python.c
+++ b/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 ();
+}
+
 \f
 
 /* 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}
 };
 
diff --git a/gdb/testsuite/gdb.python/py-frame.exp b/gdb/testsuite/gdb.python/py-frame.exp
index b91ffe62a83..4991e8a0c5d 100644
--- a/gdb/testsuite/gdb.python/py-frame.exp
+++ b/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"
diff --git a/gdb/testsuite/gdb.python/py-parameter.exp b/gdb/testsuite/gdb.python/py-parameter.exp
index 199d3bc16ec..db158ddec26 100644
--- a/gdb/testsuite/gdb.python/py-parameter.exp
+++ b/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" \
diff --git a/gdb/testsuite/gdb.rust/pp.exp b/gdb/testsuite/gdb.rust/pp.exp
index 7c7c78b5847..e3e226c5db5 100644
--- a/gdb/testsuite/gdb.rust/pp.exp
+++ b/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"