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python-gdb.py: enhance py-bt command
* Add py-bt-full command * py-bt now gives an output similar to a regular Python traceback * py-bt indicates: - if the garbage collector is running - if the thread is waiting for the GIL - detect PyCFunction_Call to get the name of the builtin function
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Lines changed: 292 additions & 18 deletions

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‎Lib/test/test_gdb.py‎

Lines changed: 123 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -13,6 +13,12 @@
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from test import test_support
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from test.test_support import run_unittest, findfile
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# Is this Python configured to support threads?
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try:
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import thread
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except ImportError:
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thread = None
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def get_gdb_version():
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try:
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proc = subprocess.Popen(["gdb", "-nx", "--version"],
@@ -728,20 +734,133 @@ def test_up_then_down(self):
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class PyBtTests(DebuggerTests):
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@unittest.skipIf(python_is_optimized(),
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"Python was compiled with optimizations")
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def test_basic_command(self):
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def test_bt(self):
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'Verify that the "py-bt" command works'
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bt = self.get_stack_trace(script=self.get_sample_script(),
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cmds_after_breakpoint=['py-bt'])
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self.assertMultilineMatches(bt,
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r'''^.*
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#[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
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Traceback \(most recent call first\):
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File ".*gdb_sample.py", line 10, in baz
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print\(42\)
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File ".*gdb_sample.py", line 7, in bar
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baz\(a, b, c\)
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File ".*gdb_sample.py", line 4, in foo
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bar\(a, b, c\)
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File ".*gdb_sample.py", line 12, in <module>
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foo\(1, 2, 3\)
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''')
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@unittest.skipIf(python_is_optimized(),
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"Python was compiled with optimizations")
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def test_bt_full(self):
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'Verify that the "py-bt-full" command works'
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bt = self.get_stack_trace(script=self.get_sample_script(),
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cmds_after_breakpoint=['py-bt-full'])
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self.assertMultilineMatches(bt,
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r'''^.*
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#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
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baz\(a, b, c\)
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#[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\)
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#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\)
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bar\(a, b, c\)
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#[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 12, in <module> \(\)
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#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 12, in <module> \(\)
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foo\(1, 2, 3\)
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''')
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@unittest.skipUnless(thread,
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"Python was compiled without thread support")
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def test_threads(self):
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'Verify that "py-bt" indicates threads that are waiting for the GIL'
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cmd = '''
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from threading import Thread
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class TestThread(Thread):
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# These threads would run forever, but we'll interrupt things with the
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# debugger
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def run(self):
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i = 0
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while 1:
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i += 1
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t = {}
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for i in range(4):
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t[i] = TestThread()
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t[i].start()
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# Trigger a breakpoint on the main thread
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print 42
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'''
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# Verify with "py-bt":
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gdb_output = self.get_stack_trace(cmd,
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cmds_after_breakpoint=['thread apply all py-bt'])
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self.assertIn('Waiting for the GIL', gdb_output)
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# Verify with "py-bt-full":
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gdb_output = self.get_stack_trace(cmd,
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cmds_after_breakpoint=['thread apply all py-bt-full'])
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self.assertIn('Waiting for the GIL', gdb_output)
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@unittest.skipIf(python_is_optimized(),
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"Python was compiled with optimizations")
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# Some older versions of gdb will fail with
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# "Cannot find new threads: generic error"
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# unless we add LD_PRELOAD=PATH-TO-libpthread.so.1 as a workaround
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@unittest.skipUnless(thread,
810+
"Python was compiled without thread support")
811+
def test_gc(self):
812+
'Verify that "py-bt" indicates if a thread is garbage-collecting'
813+
cmd = ('from gc import collect\n'
814+
'print 42\n'
815+
'def foo():\n'
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' collect()\n'
817+
'def bar():\n'
818+
' foo()\n'
819+
'bar()\n')
820+
# Verify with "py-bt":
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gdb_output = self.get_stack_trace(cmd,
822+
cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt'],
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)
824+
self.assertIn('Garbage-collecting', gdb_output)
825+
826+
# Verify with "py-bt-full":
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gdb_output = self.get_stack_trace(cmd,
828+
cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt-full'],
829+
)
830+
self.assertIn('Garbage-collecting', gdb_output)
831+
832+
@unittest.skipIf(python_is_optimized(),
833+
"Python was compiled with optimizations")
834+
# Some older versions of gdb will fail with
835+
# "Cannot find new threads: generic error"
836+
# unless we add LD_PRELOAD=PATH-TO-libpthread.so.1 as a workaround
837+
@unittest.skipUnless(thread,
838+
"Python was compiled without thread support")
839+
def test_pycfunction(self):
840+
'Verify that "py-bt" displays invocations of PyCFunction instances'
841+
# Tested function must not be defined with METH_NOARGS or METH_O,
842+
# otherwise call_function() doesn't call PyCFunction_Call()
843+
cmd = ('from time import gmtime\n'
844+
'def foo():\n'
845+
' gmtime(1)\n'
846+
'def bar():\n'
847+
' foo()\n'
848+
'bar()\n')
849+
# Verify with "py-bt":
850+
gdb_output = self.get_stack_trace(cmd,
851+
breakpoint='time_gmtime',
852+
cmds_after_breakpoint=['bt', 'py-bt'],
853+
)
854+
self.assertIn('<built-in function gmtime', gdb_output)
855+
856+
# Verify with "py-bt-full":
857+
gdb_output = self.get_stack_trace(cmd,
858+
breakpoint='time_gmtime',
859+
cmds_after_breakpoint=['py-bt-full'],
860+
)
861+
self.assertIn('#0 <built-in function gmtime', gdb_output)
862+
863+
745864
class PyPrintTests(DebuggerTests):
746865
@unittest.skipIf(python_is_optimized(),
747866
"Python was compiled with optimizations")

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