[PATCH] Add an Objfile.lookup_global_symbol function

["Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>]

Per the discussion in the thread about my gdb.lookup_global_symbol
patch, I've changed this patch to only look in GLOBAL_SCOPE.

This is essentially the inverse of Symbol.objfile. This allows
handling different symbols with the same name (but from different
objfiles) and can also be faster if the objfile is known.

gdb/ChangeLog:

2019-06-25  Christian Biesinger  <cbiesinger@google.com>

	* NEWS: Mention new function Objfile.lookup_global_symbol.
	* python/py-objfile.c (objfpy_lookup_global_symbol): New function
	  Objfile.lookup_global_symbol.

gdb/doc/ChangeLog:

2019-06-25  Christian Biesinger  <cbiesinger@google.com>

	* python.texi (Objfiles In Python): Document new function
	  Objfile.lookup_global_symbol.

gdb/testsuite/ChangeLog:

2019-06-25  Christian Biesinger  <cbiesinger@google.com>

	* gdb.python/py-objfile.c: Add global and static vars.
	* gdb.python/py-objfile.exp: Test new function Objfile.
	  lookup_global_symbol.
---
 gdb/NEWS                                |  3 ++
 gdb/doc/python.texi                     | 12 ++++++++
 gdb/python/py-objfile.c                 | 40 ++++++++++++++++++++++++-
 gdb/testsuite/gdb.python/py-objfile.c   |  3 ++
 gdb/testsuite/gdb.python/py-objfile.exp |  7 +++++
 5 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index cc1d58520d..c57cb4576e 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -36,6 +36,9 @@
   ** gdb.Type has a new property 'objfile' which returns the objfile the
      type was defined in.
 
+  ** gdb.Objfile has a new method 'lookup_global_symbol' to lookup a symbol
+     from this objfile only.
+
 * New commands
 
 | [COMMAND] | SHELL_COMMAND
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 034623513b..80da607824 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -4441,6 +4441,18 @@ searches then this function can be used to add a debug info file
 from a different place.
 @end defun
 
+@defun Objfile.lookup_global_symbol (name @r{[}, domain@r{]})
+Searches for a global symbol named @var{name} in this objfile.  Optionally, the
+search scope can be restricted with the @var{domain} argument.
+The @var{domain} argument must be a domain constant defined in the @code{gdb}
+module and described in @ref{Symbols In Python}.  This function is similar to
+@code{gdb.lookup_global_symbol}, except that the search is limited to this
+objfile.
+
+The result is a @code{gdb.Symbol} object or @code{None} if the symbol
+is not found.
+@end defun
+
 @node Frames In Python
 @subsubsection Accessing inferior stack frames from Python
 
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index 199c567a04..a9a6ae6725 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -406,7 +406,7 @@ objfpy_is_valid (PyObject *self, PyObject *args)
   Py_RETURN_TRUE;
 }
 
-/* Implementation of gdb.Objfile.add_separate_debug_file (self) -> Boolean.  */
+/* Implementation of gdb.Objfile.add_separate_debug_file (self, string) -> None.  */
 
 static PyObject *
 objfpy_add_separate_debug_file (PyObject *self, PyObject *args, PyObject *kw)
@@ -434,6 +434,39 @@ objfpy_add_separate_debug_file (PyObject *self, PyObject *args, PyObject *kw)
   Py_RETURN_NONE;
 }
 
+/* Implementation of gdb.Objfile.lookup_global_symbol (self, string [, domain]) -> gdb.Symbol.  */
+
+static PyObject *
+objfpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw)
+{
+  static const char *keywords[] = { "name", "domain", NULL };
+  objfile_object *obj = (objfile_object *) self;
+  const char *symbol_name;
+  int domain = VAR_DOMAIN;
+
+  OBJFPY_REQUIRE_VALID (obj);
+
+  if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &symbol_name,
+					&domain))
+    return nullptr;
+
+  try
+    {
+      struct symbol *sym = lookup_global_symbol_from_objfile
+        (obj->objfile, symbol_name, (domain_enum) domain).symbol;
+      if (sym == nullptr)
+	Py_RETURN_NONE;
+
+      return symbol_to_symbol_object (sym);
+    }
+  catch (const gdb_exception &except)
+    {
+      GDB_PY_HANDLE_EXCEPTION (except);
+    }
+
+  Py_RETURN_NONE;
+}
+
 /* Implement repr() for gdb.Objfile.  */
 
 static PyObject *
@@ -652,6 +685,11 @@ Return true if this object file is valid, false if not." },
     "add_separate_debug_file (file_name).\n\
 Add FILE_NAME to the list of files containing debug info for the objfile." },
 
+  { "lookup_global_symbol", (PyCFunction) objfpy_lookup_global_symbol,
+    METH_VARARGS | METH_KEYWORDS,
+    "lookup_global_symbol (name [, domain]).\n\
+Looks up a global symbol in this objfile and returns it." },
+
   { NULL }
 };
 
diff --git a/gdb/testsuite/gdb.python/py-objfile.c b/gdb/testsuite/gdb.python/py-objfile.c
index ac41491234..6d751bddae 100644
--- a/gdb/testsuite/gdb.python/py-objfile.c
+++ b/gdb/testsuite/gdb.python/py-objfile.c
@@ -15,6 +15,9 @@
    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 global_var = 42;
+static int static_var = 50;
+
 int
 main ()
 {
diff --git a/gdb/testsuite/gdb.python/py-objfile.exp b/gdb/testsuite/gdb.python/py-objfile.exp
index b5e0c5e760..2e8358bd76 100644
--- a/gdb/testsuite/gdb.python/py-objfile.exp
+++ b/gdb/testsuite/gdb.python/py-objfile.exp
@@ -55,6 +55,13 @@ gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").filename)" \
 gdb_test "python print (gdb.lookup_objfile (\"junk\"))" \
     "Objfile not found\\.\r\n${python_error_text}"
 
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_global_symbol (\"global_var\").name)" \
+    "global_var" "lookup_global_symbol finds a valid symbol"
+gdb_test "python print gdb.lookup_objfile (\"${testfile}\").lookup_global_symbol (\"static_var\") is None" \
+    "True" "lookup_global_symbol does not find static symbols"
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_global_symbol (\"stdout\"))" \
+    "None" "lookup_global_symbol doesn't find symbol in other objfile"
+
 set binfile_build_id [get_build_id $binfile]
 if [string compare $binfile_build_id ""] {
     verbose -log "binfile_build_id = $binfile_build_id"
-- 
2.22.0.657.g960e92d24f-goog