[PATCH v4] Add Objfile.lookup_{global,static}_symbol functions

["Christian Biesinger via gdb-patches" <gdb-patches at sourceware dot org>]

Thanks Eli, fixed in this version.

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:

2019-07-25  Christian Biesinger  <cbiesinger@google.com>

	* NEWS: Mention new functions Objfile.lookup_{global,static}_symbol.
	* python/py-objfile.c (objfpy_lookup_global_symbol): New function.
	(objfpy_lookup_static_symbol): New function.
  (objfile_object_methods): Add new functions.

gdb/doc/ChangeLog:

2019-07-25  Christian Biesinger  <cbiesinger@google.com>

	* python.texi (Objfiles In Python): Document new functions
	  Objfile.lookup_{global,static}_symbol.

gdb/testsuite/ChangeLog:

2019-07-25  Christian Biesinger  <cbiesinger@google.com>

	* gdb.python/py-objfile.c: Add global and static vars.
	* gdb.python/py-objfile.exp: Test new functions Objfile.
	  lookup_global_symbol and lookup_static_symbol.
---
 gdb/NEWS                                |  3 +
 gdb/doc/python.texi                     | 17 ++++++
 gdb/python/py-objfile.c                 | 78 +++++++++++++++++++++++++
 gdb/testsuite/gdb.python/py-objfile.c   |  3 +
 gdb/testsuite/gdb.python/py-objfile.exp | 14 +++++
 5 files changed, 115 insertions(+)

diff --git a/gdb/NEWS b/gdb/NEWS
index cc1d58520d..d8fb4cfe7f 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 new methods 'lookup_global_symbol' and
+     'lookup_static_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..bbba519ffc 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -4441,6 +4441,23 @@ 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{]})
+Search 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
+
+@defun Objfile.lookup_static_symbol (name @r{[}, domain@r{]})
+Like @code{Objfile.lookup_global_symbol}, but searches for a global
+symbol with static linkage named @var{name} in this objfile.
+@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 15735c8501..2c548450b4 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -434,6 +434,74 @@ 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, GLOBAL_BLOCK, 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;
+}
+
+/* Implementation of
+  gdb.Objfile.lookup_static_symbol (self, string [, domain]) -> gdb.Symbol.  */
+
+static PyObject *
+objfpy_lookup_static_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, STATIC_BLOCK, 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 +720,16 @@ 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\
+Look up a global symbol in this objfile and return it." },
+
+  { "lookup_static_symbol", (PyCFunction) objfpy_lookup_static_symbol,
+    METH_VARARGS | METH_KEYWORDS,
+    "lookup_static_symbol (name [, domain]).\n\
+Look up a static-linkage global symbol in this objfile and return 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..1b8acf47ed 100644
--- a/gdb/testsuite/gdb.python/py-objfile.exp
+++ b/gdb/testsuite/gdb.python/py-objfile.exp
@@ -55,6 +55,20 @@ 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 symbol"
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_global_symbol (\"stdout\"))" \
+    "None" "lookup_global_symbol doesn't find symbol in other objfile"
+
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_static_symbol (\"static_var\").name)" \
+    "static_var" "lookup_static_symbol finds a valid symbol"
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_static_symbol (\"global_var\")) is None" \
+    "True" "lookup_static_symbol does not find global symbol"
+gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").lookup_static_symbol (\"nonexistant\"))" \
+    "None" "lookup_static_symbol can handle nonexistant symbol"
+
 set binfile_build_id [get_build_id $binfile]
 if [string compare $binfile_build_id ""] {
     verbose -log "binfile_build_id = $binfile_build_id"
-- 
2.22.0.709.g102302147b-goog