gdbinit

# If you use the GNU debugger gdb to debug the Python C runtime, you
	# might find some of the following commands useful.  Copy this to your
	# ~/.gdbinit file and it'll get loaded into gdb automatically when you
	# start it up.  Then, at the gdb prompt you can do things like:
	#
	#    (gdb) pyo apyobjectptr
	#    <module 'foobar' (built-in)>
	#    refcounts: 1
	#    address    : 84a7a2c
	#    $1 = void
	#    (gdb)
	#
	# NOTE: If you have gdb 7 or later, it supports debugging of Python directly
	# with embedded macros that you may find superior to what is in here.
	# See Tools/gdb/libpython.py and http://bugs.python.org/issue8032.

	# Prints a representation of the object to stderr, along with the
	# number of reference counts it current has and the hex address the
	# object is allocated at.  The argument must be a PyObject*
	define pyo
	    # side effect of calling _PyObject_Dump is to dump the object's
	    # info - assigning just prevents gdb from printing the
	    # NULL return value
	    set $_unused_void = _PyObject_Dump($arg0)
	end

	# Prints a representation of the object to stderr, along with the
	# number of reference counts it current has and the hex address the
	# object is allocated at.  The argument must be a PyGC_Head*
	define pyg
	    print _PyGC_Dump($arg0)
	end

	# print the local variables of the current frame
	define pylocals
	    set $_i = 0
	    while $_i < f->f_code->co_nlocals
	        if f->f_localsplus + $_i != 0
	            set $_names = co->co_varnames
	            set $_name = PyString_AsString(PyTuple_GetItem($_names, $_i))
	            printf "%s:\n", $_name
	            pyo f->f_localsplus[$_i]
	        end
	        set $_i = $_i + 1
	    end
	end

	# A rewrite of the Python interpreter's line number calculator in GDB's
	# command language
	define lineno
	    set $__continue = 1
	    set $__co = f->f_code
	    set $__lasti = f->f_lasti
	    set $__sz = ((PyStringObject *)$__co->co_lnotab)->ob_size/2
	    set $__p = (unsigned char *)((PyStringObject *)$__co->co_lnotab)->ob_sval
	    set $__li = $__co->co_firstlineno
	    set $__ad = 0
	    while ($__sz-1 >= 0 && $__continue)
	      set $__sz = $__sz - 1
	      set $__ad = $__ad + *$__p
	      set $__p = $__p + 1
	      if ($__ad > $__lasti)
	        set $__continue = 0
	      else
	        set $__li = $__li + *$__p
	        set $__p = $__p + 1
	      end
	    end
	    printf "%d", $__li
	end

	# print the current frame - verbose
	define pyframev
	    pyframe
	    pylocals
	end

	define pyframe
	    set $__fn = (char *)((PyStringObject *)co->co_filename)->ob_sval
	    set $__n = (char *)((PyStringObject *)co->co_name)->ob_sval
	    printf "%s (", $__fn
	    lineno
	    printf "): %s\n", $__n
	### Uncomment these lines when using from within Emacs/XEmacs so it will
	### automatically track/display the current Python source line
	#    printf "%c%c%s:", 032, 032, $__fn
	#    lineno
	#    printf ":1\n"
	end

	### Use these at your own risk.  It appears that a bug in gdb causes it
	### to crash in certain circumstances.

	#define up
	#    up-silently 1
	#    printframe
	#end

	#define down
	#    down-silently 1
	#    printframe
	#end

	define printframe
	    if $pc > PyEval_EvalFrameEx && $pc < PyEval_EvalCodeEx
	        pyframe
	    else
	        frame
	    end
	end

	# Here's a somewhat fragile way to print the entire Python stack from gdb.
	# It's fragile because the tests for the value of $pc depend on the layout
	# of specific functions in the C source code.

	# Explanation of while and if tests: We want to pop up the stack until we
	# land in Py_Main (this is probably an incorrect assumption in an embedded
	# interpreter, but the test can be extended by an interested party).  If
	# Py_Main <= $pc <= Py_GetArgcArv is true, $pc is in Py_Main(), so the while
	# tests succeeds as long as it's not true.  In a similar fashion the if
	# statement tests to see if we are in PyEval_EvalFrameEx().

	# Note: The name of the main interpreter function and the function which
	# follow it has changed over time.  This version of pystack works with this
	# version of Python.  If you try using it with older or newer versions of
	# the interpreter you may will have to change the functions you compare with
	# $pc.

	# print the entire Python call stack
	define pystack
	    while $pc < Py_Main || $pc > Py_GetArgcArgv
	        if $pc > PyEval_EvalFrameEx && $pc < PyEval_EvalCodeEx
	            pyframe
	        end
	        up-silently 1
	    end
	    select-frame 0
	end

	# print the entire Python call stack - verbose mode
	define pystackv
	    while $pc < Py_Main || $pc > Py_GetArgcArgv
	        if $pc > PyEval_EvalFrameEx && $pc < PyEval_EvalCodeEx
	            pyframev
	        end
	        up-silently 1
	    end
	    select-frame 0
	end

	# generally useful macro to print a Unicode string
	def pu
	  set $uni = $arg0
	  set $i = 0
	  while (*$uni && $i++<100)
	    if (*$uni < 0x80)
	      print *(char*)$uni++
	    else
	      print /x *(short*)$uni++
	    end
	  end
	end