gdb/gdb-python-gil.patch

Index: gdb-7.11.50.20160630/gdb/doc/python.texi
===================================================================
--- gdb-7.11.50.20160630.orig/gdb/doc/python.texi	2016-07-03 16:30:37.009338358 +0200
+++ gdb-7.11.50.20160630/gdb/doc/python.texi	2016-07-03 16:30:42.812387867 +0200
@@ -229,6 +229,14 @@
 return value is @code{None}.  If @var{to_string} is @code{True}, the
 @value{GDBN} virtual terminal will be temporarily set to unlimited width
 and height, and its pagination will be disabled; @pxref{Screen Size}.
+
+The @var{release_gil} flag specifies whether @value{GDBN} ought to
+release the Python GIL before executing the command.  This is useful
+in multi-threaded Python programs where by default the Python
+interpreter will acquire the GIL and lock other threads from
+executing.  After the command has completed executing in @value{GDBN}
+the Python GIL is reacquired. This flag must be a boolean value.  If
+omitted, it defaults to @code{False}.
 @end defun
 
 @findex gdb.breakpoints
Index: gdb-7.11.50.20160630/gdb/python/python-internal.h
===================================================================
--- gdb-7.11.50.20160630.orig/gdb/python/python-internal.h	2016-07-03 16:30:37.010338366 +0200
+++ gdb-7.11.50.20160630/gdb/python/python-internal.h	2016-07-03 16:30:42.812387867 +0200
@@ -140,6 +140,8 @@
 #define PyGILState_Release(ARG) ((void)(ARG))
 #define PyEval_InitThreads()
 #define PyThreadState_Swap(ARG) ((void)(ARG))
+#define PyEval_SaveThread() ((void)(ARG))
+#define PyEval_RestoreThread(ARG) ((void)(ARG))
 #define PyEval_ReleaseLock()
 #endif
 
Index: gdb-7.11.50.20160630/gdb/python/python.c
===================================================================
--- gdb-7.11.50.20160630.orig/gdb/python/python.c	2016-07-03 16:30:37.011338375 +0200
+++ gdb-7.11.50.20160630/gdb/python/python.c	2016-07-03 16:31:16.324673783 +0200
@@ -619,13 +619,18 @@
 {
   const char *arg;
   PyObject *from_tty_obj = NULL, *to_string_obj = NULL;
-  int from_tty, to_string;
-  static char *keywords[] = {"command", "from_tty", "to_string", NULL };
+  PyObject *release_gil_obj = NULL;
+  int from_tty, to_string, release_gil;
+  static char *keywords[] = {"command", "from_tty", "to_string",
+			     "release_gil", NULL };
   char *result = NULL;
+  /* Initialize it just to avoid a GCC false warning.  */
+  PyThreadState *state = NULL;
 
-  if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!O!", keywords, &arg,
+  if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!O!O!", keywords, &arg,
 				     &PyBool_Type, &from_tty_obj,
-				     &PyBool_Type, &to_string_obj))
+				     &PyBool_Type, &to_string_obj,
+				     &PyBool_Type, &release_gil_obj))
     return NULL;
 
   from_tty = 0;
@@ -646,6 +651,15 @@
       to_string = cmp;
     }
 
+  release_gil = 0;
+  if (release_gil_obj)
+    {
+      int cmp = PyObject_IsTrue (release_gil_obj);
+      if (cmp < 0)
+	return NULL;
+      release_gil = cmp;
+    }
+
   TRY
     {
       /* Copy the argument text in case the command modifies it.  */
@@ -653,6 +667,13 @@
       struct cleanup *cleanup = make_cleanup (xfree, copy);
       struct interp *interp;
 
+      /* In the case of long running GDB commands, allow the user to
+	 release the Python GIL acquired by Python.  Restore the GIL
+	 after the command has completed before handing back to
+	 Python.  */
+      if (release_gil)
+	state = PyEval_SaveThread();
+
       make_cleanup_restore_integer (&current_ui->async);
       current_ui->async = 0;
 
@@ -671,11 +692,23 @@
 	  execute_command (copy, from_tty);
 	}
 
+      /* Reacquire the GIL if it was released earlier.  */
+      if (release_gil)
+	PyEval_RestoreThread (state);
+
       do_cleanups (cleanup);
     }
   CATCH (except, RETURN_MASK_ALL)
     {
-      GDB_PY_HANDLE_EXCEPTION (except);
+      if (except.reason < 0)
+	{
+	  /* Reacquire the GIL if it was released earlier.  */
+	  if (release_gil)
+	    PyEval_RestoreThread (state);
+
+	  gdbpy_convert_exception (except);
+	  return NULL;
+	}
     }
   END_CATCH
 
Index: gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.c	2016-07-03 16:30:42.813387876 +0200
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int
+main (void)
+{
+  int i;
+  for (i = 0; i < 10; i++)
+    {
+      sleep (1); /* break-here */
+      printf ("Sleeping %d\n", i);
+    }
+}
Index: gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.exp
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.exp	2016-07-03 16:30:42.813387876 +0200
@@ -0,0 +1,69 @@
+# Copyright (C) 2014 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/>.
+
+standard_testfile .c .py
+set executable $testfile
+
+if { [prepare_for_testing $testfile.exp $executable $srcfile] } {
+    return -1
+}
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+if ![runto_main] {
+    return -1
+}
+
+gdb_breakpoint $srcfile:[gdb_get_line_number "break-here"] temporary
+gdb_continue_to_breakpoint "break-here" ".* break-here .*"
+
+set test "response"
+set timeout 60
+set sleeping_last -1
+set hello_last 0
+set minimal 5
+gdb_test_multiple "python execfile('$srcdir/$subdir/$srcfile2')" $test {
+    -re "Error: unable to start thread\r\n" {
+	fail $test
+	# Not $gdb_prompt-synced!
+    }
+    -re "Sleeping (\[0-9\]+)\r\n" {
+	set n $expect_out(1,string)
+	if { $sleeping_last + 1 != $n } {
+	    fail $test
+	} else {
+	    set sleeping_last $n
+	    if { $sleeping_last >= $minimal && $hello_last >= $minimal } {
+		pass $test
+	    } else {
+		exp_continue
+	    }
+	}
+    }
+    -re "Hello \\( (\[0-9\]+) \\)\r\n" {
+	set n $expect_out(1,string)
+	if { $hello_last + 1 != $n } {
+	    fail $test
+	} else {
+	    set hello_last $n
+	    if { $sleeping_last >= $minimal && $hello_last >= $minimal } {
+		pass $test
+	    } else {
+		exp_continue
+	    }
+	}
+    }
+}
Index: gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.py
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.11.50.20160630/gdb/testsuite/gdb.python/py-gil-mthread.py	2016-07-03 16:30:42.814387884 +0200
@@ -0,0 +1,22 @@
+import thread
+import time
+import gdb
+
+# Define a function for the thread
+def print_thread_hello():
+   count = 0
+   while count < 10:
+      time.sleep(1)
+      count += 1
+      print "Hello (", count, ")"
+
+# Create a threads a continue
+try:
+   thread.start_new_thread( print_thread_hello, ())
+   gdb.execute ("continue", release_gil=True)
+   
+except:
+   print "Error: unable to start thread"
+
+while 1:
+   pass