Issue #13628: python-gdb.py is now able to retrieve more frames in the Python
traceback if Python is optimized.

 * delay the lookup of the size_t type, it is not available at startup
 * The second argument of the PyFrameObjectPtr constructor is optional, as
   done in other constructors
 * iter_builtins() and iter_globals() methods of PyFrameObjectPtr returns
   an empty tuple instead of None if Python is optimized
 * Fix py-bt to handle correctly "optimized" frames
 * Frame.get_pyop() tries to get the frame pointer from PyEval_EvalCodeEx()
   if the pointer is optimized out in PyEval_EvalFrameEx()
diff --git a/Lib/test/test_gdb.py b/Lib/test/test_gdb.py
index 6d4fda1..0a2d883 100644
--- a/Lib/test/test_gdb.py
+++ b/Lib/test/test_gdb.py
@@ -32,6 +32,14 @@
 if gdbpy_version == '':
     raise unittest.SkipTest("gdb not built with embedded python support")
 
+def python_is_optimized():
+    cflags = sysconfig.get_config_vars()['PY_CFLAGS']
+    final_opt = ""
+    for opt in cflags.split():
+        if opt.startswith('-O'):
+            final_opt = opt
+    return (final_opt and final_opt != '-O0')
+
 def gdb_has_frame_select():
     # Does this build of gdb have gdb.Frame.select ?
     cmd = "--eval-command=python print(dir(gdb.Frame))"
@@ -543,6 +551,8 @@
                                  re.DOTALL),
                         'Unexpected gdb representation: %r\n%s' % (gdb_output, gdb_output))
 
+@unittest.skipIf(python_is_optimized(),
+                 "Python was compiled with optimizations")
 class PyListTests(DebuggerTests):
     def assertListing(self, expected, actual):
         self.assertEndsWith(actual, expected)
@@ -585,6 +595,8 @@
 
 class StackNavigationTests(DebuggerTests):
     @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_pyup_command(self):
         'Verify that the "py-up" command works'
         bt = self.get_stack_trace(script=self.get_sample_script(),
@@ -612,6 +624,8 @@
                             'Unable to find an older python frame\n')
 
     @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_up_then_down(self):
         'Verify "py-up" followed by "py-down"'
         bt = self.get_stack_trace(script=self.get_sample_script(),
@@ -625,6 +639,8 @@
 $''')
 
 class PyBtTests(DebuggerTests):
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_basic_command(self):
         'Verify that the "py-bt" command works'
         bt = self.get_stack_trace(script=self.get_sample_script(),
@@ -636,10 +652,12 @@
 #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\)
     bar\(a, b, c\)
 #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 12, in <module> \(\)
-foo\(1, 2, 3\)
+    foo\(1, 2, 3\)
 ''')
 
 class PyPrintTests(DebuggerTests):
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_basic_command(self):
         'Verify that the "py-print" command works'
         bt = self.get_stack_trace(script=self.get_sample_script(),
@@ -648,18 +666,24 @@
                                     r".*\nlocal 'args' = \(1, 2, 3\)\n.*")
 
     @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_print_after_up(self):
         bt = self.get_stack_trace(script=self.get_sample_script(),
                                   cmds_after_breakpoint=['py-up', 'py-print c', 'py-print b', 'py-print a'])
         self.assertMultilineMatches(bt,
                                     r".*\nlocal 'c' = 3\nlocal 'b' = 2\nlocal 'a' = 1\n.*")
 
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_printing_global(self):
         bt = self.get_stack_trace(script=self.get_sample_script(),
                                   cmds_after_breakpoint=['py-print __name__'])
         self.assertMultilineMatches(bt,
                                     r".*\nglobal '__name__' = '__main__'\n.*")
 
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_printing_builtin(self):
         bt = self.get_stack_trace(script=self.get_sample_script(),
                                   cmds_after_breakpoint=['py-print len'])
@@ -667,6 +691,8 @@
                                     r".*\nbuiltin 'len' = <built-in function len>\n.*")
 
 class PyLocalsTests(DebuggerTests):
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_basic_command(self):
         bt = self.get_stack_trace(script=self.get_sample_script(),
                                   cmds_after_breakpoint=['py-locals'])
@@ -674,6 +700,8 @@
                                     r".*\nargs = \(1, 2, 3\)\n.*")
 
     @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_locals_after_up(self):
         bt = self.get_stack_trace(script=self.get_sample_script(),
                                   cmds_after_breakpoint=['py-up', 'py-locals'])
@@ -681,15 +709,6 @@
                                     r".*\na = 1\nb = 2\nc = 3\n.*")
 
 def test_main():
-    cflags = sysconfig.get_config_vars()['PY_CFLAGS']
-    final_opt = ""
-    for opt in cflags.split():
-        if opt.startswith('-O'):
-            final_opt = opt
-    if final_opt and final_opt != '-O0':
-        raise unittest.SkipTest("Python was built with compiler optimizations, "
-                                "tests can't reliably succeed")
-
     run_unittest(PrettyPrintTests,
                  PyListTests,
                  StackNavigationTests,