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Filename : python3.stp
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// python 3 tapset
// Copyright (C) 2016 Red Hat Inc.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

// Here we store to address of 'PyObject_GenericGetAttr', which we use
// down in Py3Object_GetAttr().
private global Py3Object_GenericGetAttr_addr = 0

%{
/*
 * Defines borrowed from object.h.
 */
 
/* These flags are used to determine if a type is a subclass. */
#define Py3_TPFLAGS_LONG_SUBCLASS        (1L<<24)
#define Py3_TPFLAGS_LIST_SUBCLASS        (1L<<25)
#define Py3_TPFLAGS_TUPLE_SUBCLASS       (1L<<26)
#define Py3_TPFLAGS_BYTES_SUBCLASS       (1L<<27)
#define Py3_TPFLAGS_UNICODE_SUBCLASS     (1L<<28)
#define Py3_TPFLAGS_DICT_SUBCLASS        (1L<<29)
#define Py3_TPFLAGS_BASE_EXC_SUBCLASS    (1L<<30)
#define Py3_TPFLAGS_TYPE_SUBCLASS        (1L<<31)

/*
 * Defines borrowed from code.h.
 */

/* Masks for co_flags above */
#define Py3_CO_OPTIMIZED	0x0001
#define Py3_CO_NEWLOCALS	0x0002
#define Py3_CO_VARARGS		0x0004
#define Py3_CO_VARKEYWORDS	0x0008
#define Py3_CO_NESTED		0x0010
#define Py3_CO_GENERATOR	0x0020
/* The Py3_CO_NOFREE flag is set if there are no free or cell variables.
   This information is redundant, but it allows a single flag test
   to determine whether there is any extra work to be done when the
   call frame it setup.
*/
#define Py3_CO_NOFREE       0x0040

/*
 * Defines borrowed from longintrepr.h
 */
#define Py3Long_SHIFT_SMALL	15
#define Py3Long_SHIFT_BIG	30

%}

#
# Macros to cast to various python 3 types
#

###########################################
#
# FIXME: We've got a couple of problems with @cast() here.
#
# 1) The first thing in the @cast module list is 'python3'. On some
#    systems, the python3 executable is just named
#    'python'. Systemtap's configure script finds the right name for
#    the python 3 executable, but that information doesn't make it
#    here. This file may need to be generated at systemtap build time
#    (i.e. have a 'python3.stp.in' tapset file that gets turned into
#    'python3.stp').
#
# 2) Because @cast module paths doesn't support wildcards (see
#    PR20394), we have to list 64-bit and 32-bit versions of the
#    python 3.4, 3.5, and 3.6 versions of the shared library.
#
###########################################

@define Py3ModuleList %(
    "python3:/usr/lib64/libpython3.6.so:/usr/lib64/libpython3.6m.so:/usr/lib64/libpython3.5m.so:/usr/lib64/libpython3.4m.so:/usr/lib/libpython3.6.so:/usr/lib/libpython3.6m.so:/usr/lib/libpython3.5m.so:/usr/lib/libpython3.4m.so"
%)

@define Py3Object(object) %(
    @cast(@object, "PyObject", @Py3ModuleList)
%)
@define Py3VarObject(object) %(
    @cast(@object, "PyVarObject", @Py3ModuleList)
%)
@define Py3LongObject(object) %(
    @cast(@object, "PyLongObject", @Py3ModuleList)
%)
@define Py3BytesObject(object) %(
    @cast(@object, "PyBytesObject", @Py3ModuleList)
%)
@define Py3UnicodeObject(object) %(
    @cast(@object, "PyUnicodeObject", @Py3ModuleList)
%)
@define Py3TypeObject(object) %(
    @cast(@object, "PyTypeObject", @Py3ModuleList)
%)
@define Py3TupleObject(object) %(
    @cast(@object, "PyTupleObject", @Py3ModuleList)
%)
@define Py3ListObject(object) %(
    @cast(@object, "PyListObject", @Py3ModuleList)
%)
@define Py3SetObject(object) %(
    @cast(@object, "PySetObject", @Py3ModuleList)
%)
@define Py3DictObject(object) %(
    @cast(@object, "PyDictObject", @Py3ModuleList)
%)
@define Py3DictEntry(object) %(
    @cast(@object, "PyDictEntry", @Py3ModuleList)
%)
@define Py3DictKeysObject(object) %(
    @cast(@object, "PyDictKeysObject", @Py3ModuleList)
%)
@define Py3DictKeyEntry(object) %(
    @cast(@object, "PyDictKeyEntry", @Py3ModuleList)
%)
@define Py3FrameObject(object) %(
    @cast(@object, "PyFrameObject", @Py3ModuleList)
%)
@define Py3CodeObject(object) %(
    @cast(@object, "PyCodeObject", @Py3ModuleList)
%)

@define Py3ASCIIObject(object) %(
    @cast(@object, "PyASCIIObject", @Py3ModuleList)
%)
@define Py3ASCIIObject_Sizeof %(
    @cast_module_sizeof(@Py3ModuleList, "PyASCIIObject")
%)

@define Py3CompactUnicodeObject(object) %(
    @cast(@object, "PyCompactUnicodeObject", @Py3ModuleList)
%)
@define Py3CompactUnicodeObject_Sizeof %(
    @cast_module_sizeof(@Py3ModuleList, "PyCompactUnicodeObject")
%)

#
# Systemtap macros based on C macros in object.h.
#

@define Py3_REFCNT(object) %(
    @Py3Object(@object)->ob_refcnt
%)
@define Py3_TYPE(object) %(
    @Py3Object(@object)->ob_type
%)
@define Py3_SIZE(object) %(
    @Py3VarObject(@object)->ob_size
%)

@define Py3Type_HasFeature(t, f) %(
    ((@t->tp_flags & (@f)) != 0)
%)
@define Py3Type_FastSubclass(t, f) %(
    @Py3Type_HasFeature(@t, @f)
%)

#
# Systemtap macros based on C macros in bytesobject.h.
#

@define Py3Bytes_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_BYTES_SUBCLASS %})
%)

#
# Systemtap macros based on C macros in unicodeobject.h.
#

@define Py3Unicode_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_UNICODE_SUBCLASS %})
%)

/* Returns the length of the unicode string. */
@define Py3Unicode_GET_LENGTH(op) %(
    ((@Py3Unicode_Check(@op) && @Py3Unicode_IS_READY(@op))
     ? @Py3ASCIIObject(@op)->length : 0)
%)

@define Py3Unicode_IS_READY(op) %(
    @Py3ASCIIObject(@op)->state->ready
%)

@define Py3Unicode_IS_ASCII(op) %(
    (@Py3Unicode_Check(@op) && @Py3Unicode_IS_READY(@op)
     && @Py3ASCIIObject(@op)->state->ascii)
%)

/* Return true if the string is compact or 0 if not.
   No type checks or Ready calls are performed. */
@define Py3Unicode_IS_COMPACT(op) %(
    (@Py3ASCIIObject(@op)->state->compact)
%)

/* Return a void pointer to the raw unicode buffer. */
@define _Py3Unicode_COMPACT_DATA(op) %(
    (@Py3Unicode_IS_ASCII(@op)
     ? (@op + @Py3ASCIIObject_Sizeof)
     : (@op + @Py3CompactUnicodeObject_Sizeof))
%)
@define _Py3Unicode_NONCOMPACT_DATA(op) %(
    (@Py3UnicodeObject(@op)->data->any)
%)
@define Py3Unicode_DATA(op) %(
    (@Py3Unicode_IS_COMPACT(@op) ? @_Py3Unicode_COMPACT_DATA(@op)
     : @_Py3Unicode_NONCOMPACT_DATA(@op))
%)

#
# Systemtap macros based on C macros in longobject.h.
#

@define Py3Long_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_LONG_SUBCLASS %})
%)

#
# Systemtap macros based on C macros in dictobject.h.
#

@define Py3Dict_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_DICT_SUBCLASS %})
%)

#
# Systemtap macros based on C macros in tupleobject.h.
#

@define Py3Tuple_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_TUPLE_SUBCLASS %})
%)

#
# Systemtap macros based on C macros in listobject.h.
#

@define Py3List_Check(op) %(
    @Py3Type_FastSubclass(@Py3_TYPE(@op), %{ Py3_TPFLAGS_LIST_SUBCLASS %})
%)

#
# Systemtap functions based on C functions in longobject.c.
#

%{
/* Checking for overflow in PyLong_AsLong is a PITA since C doesn't define
 * anything about what happens when a signed integer operation overflows,
 * and some compilers think they're doing you a favor by being "clever"
 * then.  The bit pattern for the largest positive signed long is
 * (unsigned long)LONG_MAX, and for the smallest negative signed long
 * it is abs(LONG_MIN), which we could write -(unsigned long)LONG_MIN.
 * However, some other compilers warn about applying unary minus to an
 * unsigned operand.  Hence the weird "0-".
 */

#define PY3_LLONG_MIN		(-__LONG_LONG_MAX__ - 1L)
#define PY3_ABS_LLONG_MIN	(0-(unsigned long long)PY3_LLONG_MIN)
%}

/* Get a C long int from an int object or any object that has an __int__
 * method.
 *
 * On overflow, return -1 and throw an error.
 */

/*
 * The Py3Long_AsLongLong() function below is actually based on
 * PyLong_AsLong(). Python's PyLong_AsLongLong() converts the PyLong
 * to a Bytes object. This method is simpler.
 *
 * On 32-bit platforms, the default for PYLONG_BITS_IN_DIGIT is 15. On
 * 64-bit platforms, the default for PYLONG_BITS_IN_DIGIT is 30. We're
 * going to assume that to be true, even though it can be configured
 * differently.
 *
 * Since we can be on a 64-bit kernel but probing a 32-bit python 3
 * executable, we have to handle both cases at the same time.
 */

private function Py3Long_AsLongLongAndOverflow_Small:long(v:long)
{
    res = -1
    i = @Py3_SIZE(v)
    if (i == -1) {
	/* We're using 'x & 0xffff' instead of '(short)x' */
	res = -(@Py3LongObject(v)->ob_digit[0] & 0xffff)
    }
    else if (i == 0) {
	res = 0
    }
    else if (i == 1) {
	res = @Py3LongObject(v)->ob_digit[0]
    }
    else {
	sign = 1
	x = 0
	if (i < 0) {
	    sign = -1
	    i = -(i)
	}
	while (--i >= 0) {
	    prev = x
	    x = ((x << %{ Py3Long_SHIFT_SMALL %})
		 | @Py3LongObject(v)->ob_digit[i])
	    if ((x >> %{ Py3Long_SHIFT_SMALL %}) != prev) {
		error("Python int too large")
		return res
	    }
	}
	/* Haven't lost any bits, but casting to long requires extra
	 * care (see comment above).
	 */
        if (x <= %{ __LONG_LONG_MAX__ %}) {
            res = x * sign
        }
        else if (sign < 0 && x == %{ PY3_ABS_LLONG_MIN %}) {
            res = %{ PY3_LLONG_MIN %}
        }
        else {
	    error("Python int too large")
            /* res is already set to -1 */
	}
    }
    return res
}

private function Py3Long_AsLongLongAndOverflow_Big:long(v:long)
{
    res = -1
    i = @Py3_SIZE(v)
    if (i == -1) {
	/* We're using 'x & 0xffffffff' instead of '(int32_t)x' */
	res = -(@Py3LongObject(v)->ob_digit[0] & 0xffffffff)
    }
    else if (i == 0) {
	res = 0
    }
    else if (i == 1) {
	res = @Py3LongObject(v)->ob_digit[0]
    }
    else {
	sign = 1
	x = 0
	if (i < 0) {
	    sign = -1
	    i = -(i)
	}
	while (--i >= 0) {
	    prev = x
	    x = ((x << %{ Py3Long_SHIFT_BIG %})
		 | @Py3LongObject(v)->ob_digit[i])
	    if ((x >> %{ Py3Long_SHIFT_BIG %}) != prev) {
		error("Python int too large")
		return res
	    }
	}
	/* Haven't lost any bits, but casting to long requires extra
	 * care (see comment above).
	 */
        if (x <= %{ __LONG_LONG_MAX__ %}) {
            res = x * sign
        }
        else if (sign < 0 && x == %{ PY3_ABS_LLONG_MIN %}) {
            res = %{ PY3_LLONG_MIN %}
        }
        else {
	    error("Python int too large")
            /* res is already set to -1 */
	}
    }
    return res
}

private function Py3Long_AsLongLong:long(v:long)
{
    if (! @Py3Long_Check(v)) {    
	error(sprintf("Py3Long_AsLong called on %s object at %p",
	      python3_get_typename(v), v))
	return -1
    }

%( CONFIG_64BIT == "y" %?
%( CONFIG_COMPAT == "y" %?
    if (@__compat_task) {
    	return Py3Long_AsLongLongAndOverflow_Small(v)
    }
%)
    return Py3Long_AsLongLongAndOverflow_Big(v)
%:
    return Py3Long_AsLongLongAndOverflow_Small(v)
%)
}

#
# Systemtap functions based on C functions in bytesobject.c.
#

private function Py3Bytes_Size:long(object:long)
{
    if (! @Py3Bytes_Check(object)) {
	# NB: python code returns string_getsize(), creating a new
	# string representation of the object, then returning the
	# length of the new string. We can't create new objects here,
	# so we'll just quit.
	warn(sprintf("Py3Bytes_Size called on non-bytes object address 0x%p\n",
		     object))
	return 0
    }
    return @Py3_SIZE(object)
}

#
# Systemtap functions based on C functions in unicodeobject.c.
#

private function Py3Unicode_AsASCIIString:string(object:long)
{
    if (!@Py3Unicode_Check(object)) {
	# NB: python returns value of string_getbuffer() here
	# (basically getting a string representation of any
	# object). We can't create new objects here, so we'll
	# just quit.
	warn(sprintf("Py3Unicode_AsASCIIString called on non-string address 0x%p\n",
		     object))
	return ""
    }
    if (@Py3Unicode_IS_ASCII(object)) {
        try {
	    return user_string_n(@Py3Unicode_DATA(object),
				 @Py3Unicode_GET_LENGTH(object))
	} catch {
	    warn(sprintf("Py3Unicode_AsASCIIString failed on address 0x%p\n",
			 object))
	}
	return ""
    }
    try {
	return text_str(user_string_n(@Py3Unicode_DATA(object),
				      @Py3Unicode_GET_LENGTH(object)))
    } catch {
	warn(sprintf("Py3Unicode_AsASCIIString failed(2) on address 0x%p\n",
		     @Py3Unicode_DATA(object)))
    }
    return ""
}

#
# Systemtap functions based on C functions in codeobject.c.
#

private function Py3Code_Addr2Line:long(code:long, addrq:long)
{
    /*
     * co_lnotab is used to compute the line number from a bytecode
     * index, addrq. See the file Objects/lnotab_notes.txt in the
     * python source for the details of the lnotab representation.
     *
     * We can't treat co_lnotab as a "real" null terminated string,
     * since co_lnotab can have embedded null characters. So, we'll
     * grab it character by character.
     */
    size = Py3Bytes_Size(@Py3CodeObject(code)->co_lnotab) / 2
    co_lnotab_sval = @Py3BytesObject(@Py3CodeObject(code)->co_lnotab)->ob_sval
    line = @Py3CodeObject(code)->co_firstlineno
    addr = 0
    p = 0
    while (--size >= 0) {
    	addr += user_char(co_lnotab_sval + p++)
	if (addr > addrq)
	    break
	    
	line += user_char(co_lnotab_sval + p++)
    }
    return line
}

#
# Systemtap functions based on C functions in frameobject.c.
#

private function Py3Frame_GetLineNumber:long(frame:long)
{
    if (@Py3FrameObject(frame)->f_trace)
	return @Py3FrameObject(frame)->f_lineno
    else
	return Py3Code_Addr2Line(@Py3FrameObject(frame)->f_code,
				 @Py3FrameObject(frame)->f_lasti)
}

#
# Systemtap functions based on C functions in tupleobject.c.
#

private function Py3Tuple_GetItem:long(op:long, i:long)
{
    if (!@Py3Tuple_Check(op)) {
	error(sprintf("Py3Tuple_GetItem called on %s object at %p",
		      python3_get_typename(op), op))
	return 0
    }
    if (i < 0 || i >= @Py3_SIZE(op)) {
        error(sprintf("tuple index %d out of range (%d)", i, @Py3_SIZE(op)))
        return 0
    }
    return @Py3TupleObject(op)->ob_item[i]
}

private function Py3Tuple_Repr:string(object:long)
{
    if (!@Py3Tuple_Check(object)) {
	error(sprintf("Py3Tuple_Repr called on %s object at %p",
		      python3_get_typename(object), object))
	return ""
    }
    n = @Py3_SIZE(object)
    if (n == 0)
	return "()"

    retstr = "("
    first = 1
    for (i = 0; i < n; i++) {
	if (! first)
	    retstr .= " "
	first = 0
	retstr .= Py3Object_Repr(Py3Tuple_GetItem(object, i))
    }
    retstr .= ")"
    return retstr
}

#
# Systemtap functions based on C functions in listobject.c.
#

private function Py3List_GetItem:long(op:long, i:long)
{
    if (!@Py3List_Check(op)) {
	error(sprintf("Py3List_GetItem called on %s object at %p",
		      python3_get_typename(op), op))
        return 0
    }
    if (i < 0 || i >= @Py3_SIZE(op)) {
        error(sprintf("tuple index %d out of range (%d)", i, @Py3_SIZE(op)))
        return 0
    }
    return @Py3ListObject(op)->ob_item[i]
}

private function Py3List_Repr:string(object:long)
{
    if (!@Py3List_Check(object)) {
	error(sprintf("Py3List_Repr called on %s object at %p",
		      python3_get_typename(object), object))
	return ""
    }
    n = @Py3_SIZE(object)
    if (n == 0)
	return "[]"

    retstr = "["
    first = 1
    for (i = 0; i < n; i++) {
	if (! first)
	    retstr .= " "
	first = 0
	retstr .= Py3Object_Repr(Py3List_GetItem(object, i))
    }
    retstr .= "]"
    return retstr
}

#
# Systemtap functions based on C functions in dictobject.c.
#

@define DK_SIZE(dk) %(
    @Py3DictKeysObject(@dk)->dk_size
%)
@define DK_IXSIZE(dk) %(
    %( CONFIG_64BIT == "y" %?
	%( CONFIG_COMPAT == "y" %?
	    (@__compat_task
	     ? (@DK_SIZE(@dk) <= 0xff ? 1 : (@DK_SIZE(@dk) <= 0xffff ? 2 : 4))
	     : (@DK_SIZE(@dk) <= 0xff ?
		1 : (@DK_SIZE(@dk) <= 0xffff ?
		2 : (@DK_SIZE(@dk) <= 0xffffffff ? 4 : 8))))
	%:
	    (@DK_SIZE(@dk) <= 0xff ?
	     1 : (@DK_SIZE(@dk) <= 0xffff ?
	     2 : (@DK_SIZE(@dk) <= 0xffffffff ? 4 : 8)))
	%)
    %:
	(@DK_SIZE(@dk) <= 0xff ? 1 : (@DK_SIZE(@dk) <= 0xffff ? 2 : 4))
    %)
%)

@define DK_ENTRIES(dk) %(
     (@choose_defined(@Py3DictKeysObject(@dk)->dk_entries,
      (&@Py3DictKeyEntry(&@Py3DictKeysObject(@dk)->dk_indices->as_1[@DK_SIZE(@dk) * @DK_IXSIZE(@dk)]))))
%)

private function Py3Dict_GetItem:long(op:long, key:string)
{
    if (!@Py3Dict_Check(op)) {
	error(sprintf("Py3Dict_GetItem called on %s object at %p",
		      python3_get_typename(op), @__pointer(op)))
        return 0
    }
    // We'd like to hash 'key' here, but we can't (easily). Python
    // randomizes its hash function at python process startup. So,
    // instead of hashing the key and then searching for that hash in
    // the dictionary, we'll do a linear search of the dictionary for
    // the key.

    // In python 3, each DictObject can be in one of two forms.
    //
    // Either:
    //   A combined table:
    //     ma_values == NULL, dk_refcnt == 1.
    //     Values are stored in the me_value field of the PyDictKeysObject.
    // Or:
    //   A split table:
    //     ma_values != NULL, dk_refcnt >= 1
    //     Values are stored in the ma_values array.
    //     Only string (unicode) keys are allowed.

    // If we've got a split table...
    if (@Py3DictObject(op)->ma_values != 0) {
        n = @DK_SIZE(@Py3DictObject(op)->ma_keys)
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(op)->ma_keys)[i]
	    if (entry_ptr->me_key == 0
		|| ! @Py3Unicode_Check(entry_ptr->me_key))
		continue
	    if (Py3Unicode_AsASCIIString(entry_ptr->me_key) == key)
		return @Py3DictObject(op)->ma_values[i]
	}
    }
    // If we've got a combined table...
    else {
	n = @choose_defined(@Py3DictObject(op)->ma_keys->dk_nentries,
			    @DK_SIZE(@Py3DictObject(op)->ma_keys))
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(op)->ma_keys)[i]
	    if (entry_ptr->me_key == 0 || entry_ptr->me_value == 0
		|| ! @Py3Unicode_Check(entry_ptr->me_key))
		continue
	    if (Py3Unicode_AsASCIIString(entry_ptr->me_key) == key)
		return entry_ptr->me_value
	}
    }
    return 0
}

# This function isn't really based on a function in dictobject.c, but
# it is based on Py3Dict_GetItem().
private function Py3Dict_GetItem_FromLong:long(op:long, key:long)
{
    if (!@Py3Dict_Check(op)) {
	error(sprintf("Py3Dict_GetItem called on %s object at %p",
		      python3_get_typename(op), @__pointer(op)))
        return 0
    }

    // See Py3Dict_GetItem() for details on dicts.

    // If we've got a split table...
    if (@Py3DictObject(op)->ma_values != 0) {
        n = @Py3DictObject(op)->ma_used
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(op)->ma_keys)[i]
	    if (entry_ptr->me_key == 0
		|| ! @Py3Long_Check(entry_ptr->me_key))
		continue
	    if (Py3Long_AsLongLong(entry_ptr->me_key) == key)
		return @Py3DictObject(op)->ma_values[i]
	}
    }
    // If we've got a combined table...
    else {
	n = @choose_defined(@Py3DictObject(op)->ma_keys->dk_nentries,
			    @DK_SIZE(@Py3DictObject(op)->ma_keys))
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(op)->ma_keys)[i]
	    if (entry_ptr->me_key == 0 || entry_ptr->me_value == 0
		|| ! @Py3Long_Check(entry_ptr->me_key))
		continue
	    if (Py3Long_AsLongLong(entry_ptr->me_key) == key)
		return entry_ptr->me_value
	}
    }
    return 0
}

private function Py3Dict_Repr:string(object:long)
{
    if (!@Py3Dict_Check(object)) {
	error(sprintf("Py3Dict_Repr called on %s object at %p",
		      python3_get_typename(object), @__pointer(object)))
	return ""
    }

    // If we've got a split table...
    if (@Py3DictObject(object)->ma_values != 0) {
        n = @Py3DictObject(object)->ma_used
	if (n == 0)
	    return "{}"

	retstr = "{"
	first = 1
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(object)->ma_keys)[i]
	    if (entry_ptr->me_key == 0)
		continue

	    if (! first)
		retstr .= " "
	    first = 0
	    retstr .= Py3Object_Repr(entry_ptr->me_key)
	    retstr .= ":"
	    retstr .= Py3Object_Repr(@Py3DictObject(object)->ma_values[i])
	}
	retstr .= "}"
    }
    // If we've got a combined table...
    else {
	n = @choose_defined(@Py3DictObject(object)->ma_keys->dk_nentries,
			    @DK_SIZE(@Py3DictObject(object)->ma_keys))
	if (n == 0)
	    return "{}"

	retstr = "{"
	first = 1
	for (i = 0; i < n; i++) {
	    entry_ptr = &@DK_ENTRIES(@Py3DictObject(object)->ma_keys)[i]
	    if (entry_ptr->me_key == 0 || entry_ptr->me_value == 0)
		continue

	    if (! first)
		retstr .= " "
	    first = 0
	    retstr .= Py3Object_Repr(entry_ptr->me_key)
	    retstr .= ":"
	    retstr .= Py3Object_Repr(entry_ptr->me_value)
	}
	retstr .= "}"
    }
    return retstr
}

#
# Systemtap functions based on C functions in object.c.
#

function Py3Object_Repr:string(object:long)
{
    if (object == 0)
	return "<NULL>"
    if (@Py3Unicode_Check(object))
	return sprintf("\"%s\"", Py3Unicode_AsASCIIString(object))
    if (@Py3Long_Check(object))
    	return sprintf("%#x", Py3Long_AsLongLong(object))
    if (@Py3Tuple_Check(object))
	return Py3Tuple_Repr(object)
    if (@Py3List_Check(object))
	return Py3List_Repr(object)
    if (@Py3Dict_Check(object))
	return Py3Dict_Repr(object)
    return sprintf("<%s object at %p>", python3_get_typename(object),
		   @__pointer(object))
}

# This function isn't really based on a function in object.c, but
# it is based on Py3Object_Repr().
private function Py3Object_Repr:string(object:long, index:long)
{
    if (object == 0)
	return "<NULL>"
    if (@Py3Unicode_Check(object))
	return sprintf("\"%c\"", stringat(Py3Unicode_AsASCIIString(object),
					  index))
    if (@Py3Tuple_Check(object))
	return Py3Object_Repr(Py3Tuple_GetItem(object, index))
    if (@Py3List_Check(object))
	return Py3Object_Repr(Py3List_GetItem(object, index))
    if (@Py3Dict_Check(object))
	return Py3Object_Repr(Py3Dict_GetItem_FromLong(object, index))

    error(sprintf("TypeError: '%s' object cannot be indexed",
	  python3_get_typename(object)))
    return ""
}

# This function isn't really based on a function in object.c, but
# it is based on Py3Object_Repr().
private function Py3Object_GetItem:string(object:long, index:long)
{
    if (object == 0) {
	error("TypeError: None object cannot be indexed")
	return 0
    }
    if (@Py3Tuple_Check(object))
	return Py3Tuple_GetItem(object, index)
    if (@Py3List_Check(object))
	return Py3List_GetItem(object, index)
    if (@Py3Dict_Check(object))
	return Py3Dict_GetItem_FromLong(object, index)

    error(sprintf("TypeError: '%s' object cannot be indexed",
	  python3_get_typename(object)))
    return 0
}

private function Py3Object_GenericGetAttrWithDict:long(obj:long, name:string,
						       dict:long)
{
    tp = @Py3_TYPE(obj)
    if (tp->tp_dict == 0) {
	printf("Py3Object_GenericGetAttr: no tp_dict\n")
	return 0
    }

    if (dict == 0) {
	dictoffset = tp->tp_dictoffset
	if (dictoffset != 0) {
	    if (dictoffset < 0) {
		error("yikes")
	    }
	    dict = user_long(obj + dictoffset);
	}
    }
    if (dict != 0) {
	res = Py3Dict_GetItem(dict, name)
	if (res != 0)
	    return res
    }
    return 0
}

@define Py3Object_GenericGetAttr(obj, name) %(
    Py3Object_GenericGetAttrWithDict(@obj, @name, 0)
%)

function Py3Object_GetAttr:long(object:long, attr:string)
{
    if (object == 0) {
	error("The None object has no attributes")
	return 0
    }

    if (@Py3_TYPE(object)->tp_getattro == 0) {
	error(sprintf("The %s object has no attributes",
		      python3_get_typename(object)))
	return 0
    }

    // Python 3 is quite different than python 2 when it comes to
    // attributes. Classes are no longer their own type anymore, so we
    // can't really check to see if something is a class.
    //
    // The python 3.6m source uses PyObject_GenericGetAttr() for most
    // objects that support attributes. Now we need to figure out if
    // that's the function we've got. If so, we know how to handle
    // this object.
    if (Py3Object_GenericGetAttr_addr != @Py3_TYPE(object)->tp_getattro) {
	error(sprintf("Systemtap doesn't know how to get attributes from %s objects",
		      python3_get_typename(object)))
	return 0
    }

    res = @Py3Object_GenericGetAttr(object, attr)
    if (res != 0)
       return res

    error(sprintf("The %s object has no attribute '%s'",
		  python3_get_typename(object), attr))

    return 0
}

#
# Systemtap support functions for python 3.
#

/*
 * python3_print_backtrace - Print python backtrace
 *
 * Description: This function is equivalent to
 * print(python3_sprint_backtrace(frame)), except that deeper stack
 * tracing may be supported. 
 *
 * Note that users should call 'python_print_backtrace()', and the
 * translator will call the appropriate python 2 or python 3 function
 * with the correct argument.
 */
function python3_print_backtrace:long(frame:long)
{
    printf("Traceback (most recent call first):\n")
    while (frame != 0) {
	lineno = Py3Frame_GetLineNumber(frame)
	code = @Py3FrameObject(frame)->f_code
	filename = Py3Unicode_AsASCIIString(code->co_filename)
	name = Py3Unicode_AsASCIIString(code->co_name)

	# Quit when we make it back to the HelperSDT module.
	if (isinstr(filename, "/HelperSDT/"))
	    break

	printf("  File \"%s\", line %d, in %s\n", filename, lineno, name)
	# NB: We'd like to print the source line here as python does,
	# but we can't. Python opens up the file and finds the
	# appropriate line, but we can't really do that when we're in
	# the kernel.

	frame = @Py3FrameObject(frame)->f_back
    }
}

/*
 * python3_sprint_backtrace - Get python backtrace
 * 
 * Description: This function returns a string containing a python
 * backtrace.  Output may be truncated as per maximum string length
 * (MAXSTRINGLEN).
 *
 * Note that users should call 'python_sprint_backtrace()', and the
 * translator will call the appropriate python 2 or python 3 function
 * with the correct argument.
 */
function python3_sprint_backtrace:string(frame:long)
{
    retstr = "Traceback (most recent call first):\n"
    while (frame != 0) {
	lineno = Py3Frame_GetLineNumber(frame)
	code = @Py3FrameObject(frame)->f_code
	filename = Py3Unicode_AsASCIIString(code->co_filename)
	name = Py3Unicode_AsASCIIString(code->co_name)

	# Quit when we make it back to the HelperSDT module.
	if (isinstr(filename, "/HelperSDT/"))
	    break

	retstr .= sprintf("  File \"%s\", line %d, in %s\n", filename,
			  lineno, name)

	frame = @Py3FrameObject(frame)->f_back
    }
    return retstr
}


/*
 * python3_get_typename - Get python object type name
 *
 * Description: This function returns a string describing the type of
 * a python object.
 */
private function python3_get_typename:string(obj:long)
{
    if (obj == 0)
	return ""
    return user_string(@Py3_TYPE(obj)->tp_name)
}

/*
 * python3_initiatlize - Initialize python tapset
 *
 * Description: This function gets values from the HelperSDT module.
 *
 * Note that users shouldn't call this directly. The translator will
 * generate code that calls this function with the correct arguments.
 */
function python3_initialize:long(arg1:long)
{
    Py3Object_GenericGetAttr_addr = arg1
}

/*
 * python3_get_locals - Get python local variables
 *
 * Description: This function returns a list of python local variables
 * from a frame.
 *
 * frame: python frame object pointer
 * flags: 0: function parameters only ($$parms), 1: locals only
 * ($$locals), 2: all local vars, parameters and locals ($$vars)
 *
 * Note that users shouldn't call this directly, they should refer to
 * '$$parms', '$$locals', and '$$vars' in a python probe and the
 * translator will generate code that calls this function with the
 * correct arguments.
 */
function python3_get_locals:string(frame:long, flags:long)
{
    code = @Py3FrameObject(frame)->f_code
	
    # flags == 2: get all variables
    if (flags == 2) {		
	i = 0
	n = code->co_nlocals
    }
    else {
	n = code->co_argcount + code->co_kwonlyargcount
	if (code->co_flags & %{ Py3_CO_VARARGS %})
	    n++
	if (code->co_flags & %{ Py3_CO_VARKEYWORDS %})
	    n++

	# flags == 0 (parms only): 0 to n (argcount)
	if (flags == 0)
	    i = 0
	# flags == 1 (locals only): n (argcount) to max
	else if (flags == 1) {
	    i = n
	    n = code->co_nlocals
	}
    }
    if (i < 0 || i > n) {
        error(sprintf("python3_get_locals: invalid indicies (%d-%d)", i, n))
        return ""
    }
	    
    # Each element in co_varnames is a tuple of strings. The values
    # are in f_localsplus.
    p = code->co_varnames
    localsplus = @Py3FrameObject(frame)->f_localsplus
    first = 1
    for (; i < n; i++) {
	if (! first)
	    retstr .= " "
	first = 0
	key_obj = Py3Tuple_GetItem(p, i)
	value_obj = user_long(localsplus + (i * %{ sizeof(intptr_t) %}))
	retstr .= sprintf("%s=%s", Py3Unicode_AsASCIIString(key_obj),
			  Py3Object_Repr(value_obj))
    }
    return retstr
}

function python3_get_var_obj:long(frame:long, var:string)
{
    f_code = @Py3FrameObject(frame)->f_code
    n = f_code->co_nlocals
	    
    # Each element in co_varnames is a tuple of strings. The values
    # are in f_localsplus.
    p = f_code->co_varnames
    localsplus = @Py3FrameObject(frame)->f_localsplus
    for (i = 0; i < n; i++) {
	key_obj = Py3Tuple_GetItem(p, i)
	if (var == Py3Unicode_AsASCIIString(key_obj)) {
	    return user_long(localsplus + (i * %{ sizeof(intptr_t) %}))
	}
    }

    # If we can't find it in the locals, we look in the globals.
    f_globals = @Py3FrameObject(frame)->f_globals
    value_obj = Py3Dict_GetItem(f_globals, var)
    if (value_obj == 0) {
        error(sprintf("Python variable '%s' cannot be found", var))
	return 0
    }
    return value_obj
}

function python3_get_var_obj:long(frame:long, var:string, index:long)
{
    f_code = @Py3FrameObject(frame)->f_code
    n = @Py3CodeObject(f_code)->co_nlocals
	    
    # Each element in co_varnames is a tuple of strings. The values
    # are in f_localsplus.
    p = @Py3CodeObject(f_code)->co_varnames
    localsplus = @Py3FrameObject(frame)->f_localsplus
    for (i = 0; i < n; i++) {
	key_obj = Py3Tuple_GetItem(p, i)
	if (var == Py3Unicode_AsASCIIString(key_obj)) {
	    return user_long(localsplus + (i * %{ sizeof(intptr_t) %}))
	}
    }

    # If we can't find it in the locals, we look in the globals.
    f_globals = @Py3FrameObject(frame)->f_globals
    value_obj = Py3Dict_GetItem(f_globals, var)
    if (value_obj == 0) {
	error(sprintf("Python variable '%s' cannot be found", var))
	return 0
    }
    return value_obj
}