github
/
duktape
mirror of https://github.com/svaarala/duktape.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Genbuiltins.py varuint encoding tweaks

pull/1152/head
Sami Vaarala 8 years ago
parent
47b96b2cbe
commit
9f734d3434
2 changed files with 52 additions and 49 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 43
      tools/dukutil.py
  2. 58
      tools/genbuiltins.py

43
tools/dukutil.py
View File

@ -11,12 +11,14 @@ class BitEncoder:
_bits = None
_varuint_dist = None
_varuint_cats = None
_varuint_count = None
_varuint_bits = None
def __init__(self):
self._bits = []
self._varuint_dist = [ 0 ] * 65536
self._varuint_cats = [0] * 5
self._varuint_count = 0
self._varuint_bits = 0
@ -39,24 +41,31 @@ class BitEncoder:
self._varuint_dist[x] += 1
self._varuint_count += 1
if x <= 3:
self.bits(0, 1)
self.bits(x, 2)
self._varuint_bits += 3
elif x <= 65:
self.bits(1, 1)
self.bits(x - 4 + 2, 6)
self._varuint_bits += 7
elif x <= 65535:
self.bits(1, 1)
self.bits(0, 6)
self.bits(x, 16)
self._varuint_bits += 7 + 16
if x == 0:
self.bits(0, 2)
self._varuint_bits += 2
self._varuint_cats[0] += 1
elif x <= 4:
self.bits(1, 2)
self.bits(x - 1, 2)
self._varuint_bits += 2 + 2
self._varuint_cats[1] += 1
elif x <= 36:
self.bits(2, 2)
self.bits(x - 5, 5)
self._varuint_bits += 2 + 5
self._varuint_cats[2] += 1
elif x <= 163:
self.bits(3, 2)
self.bits(x - 37 + 1, 7)
self._varuint_bits += 2 + 7
self._varuint_cats[3] += 1
else:
self.bits(1, 1)
self.bits(1, 6)
self.bits(x, 32)
self._varuint_bits += 7 + 32
self.bits(3, 2)
self.bits(0, 7)
self.bits(x, 20)
self._varuint_bits += 2 + 7 + 20
self._varuint_cats[4] += 1
def getNumBits(self):
"Get current number of encoded bits."

58
tools/genbuiltins.py
View File

@ -1346,19 +1346,12 @@ ACCESSOR_PROPERTY_ATTRIBUTES = 'c'
DEFAULT_DATA_PROPERTY_ATTRIBUTES = 'wc'
# Encoding constants (must match duk_hthread_builtins.c).
CLASS_BITS = 5
BIDX_BITS = 7
STRIDX_BITS = 9 # would be nice to optimize to 8
NATIDX_BITS = 8
PROP_FLAGS_BITS = 3
LENGTH_PROP_BITS = 3
NARGS_BITS = 3
PROP_TYPE_BITS = 3
NARGS_VARARGS_MARKER = 0x07
NO_CLASS_MARKER = 0x00 # 0 = DUK_HOBJECT_CLASS_NONE
NO_BIDX_MARKER = 0x7f
NO_STRIDX_MARKER = 0xff
PROP_TYPE_DOUBLE = 0
PROP_TYPE_STRING = 1
@ -1378,16 +1371,16 @@ PROPDESC_FLAG_ACCESSOR = (1 << 3) # unused now
# Class names, numeric indices must match duk_hobject.h class numbers.
class_names = [
'Unused',
'Arguments',
'Object',
'Array',
'Function',
'Arguments',
'Boolean',
'Date',
'Error',
'Function',
'JSON',
'Math',
'Number',
'Object',
'RegExp',
'String',
'global',
@ -1395,7 +1388,8 @@ class_names = [
'DecEnv',
'Buffer',
'Pointer',
'Thread',
'Thread'
# Remaining class names are not currently needed.
]
class2num = {}
for i,v in enumerate(class_names):
@ -1517,6 +1511,7 @@ def gen_ramstr_initdata_bitpacked(meta):
if be._varuint_count > 0:
logger.debug('Varuint distribution:')
logger.debug(json.dumps(be._varuint_dist[0:1024]))
logger.debug('Varuint encoding categories: %r' % be._varuint_cats)
logger.debug('Varuint efficiency: %f bits/value' % (float(be._varuint_bits) / float(be._varuint_count)))
res = be.getByteString()
@ -1601,22 +1596,20 @@ def encode_property_flags(flags):
def gen_ramobj_initdata_for_object(meta, be, bi, string_to_stridx, natfunc_name_to_natidx, objid_to_bidx):
def _stridx(strval):
stridx = string_to_stridx[strval]
be.bits(stridx, STRIDX_BITS)
be.varuint(stridx)
def _stridx_or_string(strval):
# XXX: could share the built-in strings decoder, would save ~200 bytes.
stridx = string_to_stridx.get(strval)
if stridx is not None:
be.bits(0, 1) # marker: stridx
be.bits(stridx, STRIDX_BITS)
be.varuint(stridx + 1)
else:
be.bits(1, 1) # marker: raw bytes
be.varuint(0)
bitpack_string(be, strval)
def _natidx(native_name):
natidx = natfunc_name_to_natidx[native_name]
be.bits(natidx, NATIDX_BITS)
be.varuint(natidx)
class_num = class_to_number(bi['class'])
be.bits(class_num, CLASS_BITS)
be.varuint(class_num)
props = [x for x in bi['properties']] # clone
@ -1693,53 +1686,53 @@ def gen_ramobj_initdata_for_props(meta, be, bi, string_to_stridx, natfunc_name_t
count_function_props = 0
def _bidx(bi_id):
be.varuint(objid_to_bidx[bi_id])
def _bidx_or_none(bi_id):
if bi_id is None:
be.bits(NO_BIDX_MARKER, BIDX_BITS)
be.varuint(0)
else:
be.bits(objid_to_bidx[bi_id], BIDX_BITS)
be.varuint(objid_to_bidx[bi_id] + 1)
def _stridx(strval):
stridx = string_to_stridx[strval]
be.bits(stridx, STRIDX_BITS)
be.varuint(stridx)
def _stridx_or_string(strval):
# XXX: could share the built-in strings decoder, would save ~200 bytes.
stridx = string_to_stridx.get(strval)
if stridx is not None:
be.bits(0, 1) # marker: stridx
be.bits(stridx, STRIDX_BITS)
be.varuint(stridx + 1)
else:
be.bits(1, 1) # marker: raw bytes
be.varuint(0)
bitpack_string(be, strval)
def _natidx(native_name):
if native_name is None:
natidx = 0 # 0 is NULL in the native functions table, denotes missing function
else:
natidx = natfunc_name_to_natidx[native_name]
be.bits(natidx, NATIDX_BITS)
be.varuint(natidx)
props = [x for x in bi['properties']] # clone
# internal prototype: not an actual property so not in property list
if bi.has_key('internal_prototype'):
_bidx(bi['internal_prototype'])
_bidx_or_none(bi['internal_prototype'])
else:
_bidx(None)
_bidx_or_none(None)
# external prototype: encoded specially, steal from property list
prop_proto = steal_prop(props, 'prototype')
if prop_proto is not None:
assert(prop_proto['value']['type'] == 'object')
assert(prop_proto['attributes'] == '')
_bidx(prop_proto['value']['id'])
_bidx_or_none(prop_proto['value']['id'])
else:
_bidx(None)
_bidx_or_none(None)
# external constructor: encoded specially, steal from property list
prop_constr = steal_prop(props, 'constructor')
if prop_constr is not None:
assert(prop_constr['value']['type'] == 'object')
assert(prop_constr['attributes'] == 'wc')
_bidx(prop_constr['value']['id'])
_bidx_or_none(prop_constr['value']['id'])
else:
_bidx(None)
_bidx_or_none(None)
# name: encoded specially for function objects, so steal and ignore here
if bi['class'] == 'Function':
@ -1982,6 +1975,7 @@ def gen_ramobj_initdata_bitpacked(meta, native_funcs, natfunc_name_to_natidx, do
if be._varuint_count > 0:
logger.debug('varuint distribution:')
logger.debug(json.dumps(be._varuint_dist[0:1024]))
logger.debug('Varuint encoding categories: %r' % be._varuint_cats)
logger.debug('Varuint efficiency: %f bits/value' % (float(be._varuint_bits) / float(be._varuint_count)))
romobj_init_data = be.getByteString()
#logger.debug(repr(romobj_init_data))

Write Preview
Loading…
Cancel
Save