Author: Antonio Cuni <[email protected]>
Branch: faster-rstruct-2
Changeset: r91335:7d8f1bbfc0b1
Date: 2017-05-18 17:12 +0200
http://bitbucket.org/pypy/pypy/changeset/7d8f1bbfc0b1/
Log: delegate the alignment check to Buffer.typed_{read,write}, to take
in account also the SubBuffer's offset. Moreover, reuse the logic in
rawstorage to determine whether it is fine to do an unaligned
access, depending on the CPU
diff --git a/rpython/rlib/buffer.py b/rpython/rlib/buffer.py
--- a/rpython/rlib/buffer.py
+++ b/rpython/rlib/buffer.py
@@ -13,6 +13,21 @@
ll_for_resizable_list)
from rpython.rlib.signature import signature
from rpython.rlib import types
+from rpython.rlib import rawstorage
+
+ALLOW_UNALIGNED_ACCESS = rawstorage.misaligned_is_fine
+
[email protected]()
+def is_alignment_correct(TYPE, index):
+ if ALLOW_UNALIGNED_ACCESS:
+ return True
+ try:
+ rawstorage._check_alignment(TYPE, index)
+ except rawstorage.AlignmentError:
+ return False
+ else:
+ return True
+
class CannotRead(Exception):
"""
@@ -117,6 +132,8 @@
"""
Read the value of type TP starting at byte_offset. No bounds checks
"""
+ if not is_alignment_correct(TP, byte_offset):
+ raise CannotRead
ptr = self.get_raw_address()
return llop.raw_load(TP, ptr, byte_offset)
@@ -125,7 +142,7 @@
"""
Write the value of type TP at byte_offset. No bounds checks
"""
- if self.readonly:
+ if self.readonly or not is_alignment_correct(TP, byte_offset):
raise CannotWrite
ptr = self.get_raw_address()
value = lltype.cast_primitive(TP, value)
@@ -158,6 +175,8 @@
@specialize.ll_and_arg(1)
def typed_read(self, TP, byte_offset):
+ if not is_alignment_correct(TP, byte_offset):
+ raise CannotRead
lldata = self._get_gc_data()
byte_offset += self._get_gc_data_extra_offset()
return llop.gc_load_indexed(TP, lldata, byte_offset,
@@ -165,7 +184,7 @@
@specialize.ll_and_arg(1)
def typed_write(self, TP, byte_offset, value):
- if self.readonly:
+ if self.readonly or not is_alignment_correct(TP, byte_offset):
raise CannotWrite
lldata = self._get_gc_data()
byte_offset += self._get_gc_data_extra_offset()
diff --git a/rpython/rlib/rstruct/standardfmttable.py
b/rpython/rlib/rstruct/standardfmttable.py
--- a/rpython/rlib/rstruct/standardfmttable.py
+++ b/rpython/rlib/rstruct/standardfmttable.py
@@ -33,17 +33,17 @@
@specialize.argtype(0)
def do_pack_fastpath(fmtiter, value):
size = rffi.sizeof(TYPE)
- pos = fmtiter.pos
if (not USE_FASTPATH or
fmtiter.bigendian != native_is_bigendian or
- not native_is_ieee754 or
- pos % size != 0):
+ not native_is_ieee754):
raise CannotWrite
#
- if not ALLOW_FASTPATH:
- raise ValueError("fastpath not allowed :(")
# typed_write() might raise CannotWrite
fmtiter.wbuf.typed_write(TYPE, fmtiter.pos, value)
+ if not ALLOW_FASTPATH:
+ # if we are here it means that typed_write did not raise, and thus
+ # the fast path was actually taken
+ raise ValueError("fastpath not allowed :(")
fmtiter.advance(size)
#
@specialize.argtype(0)
@@ -203,12 +203,7 @@
def do_unpack_fastpath(fmtiter):
size = rffi.sizeof(TYPE)
buf, pos = fmtiter.get_buffer_and_pos()
- if pos % size != 0 or not USE_FASTPATH:
- # XXX: maybe we are too conservative here? On most architectures,
- # it is possible to read the data even if pos is not
- # aligned. Also, probably it should responsibility of
- # buf.typed_read to raise CannotRead in case it is not aligned
- # *and* it is not supported.
+ if not USE_FASTPATH:
raise CannotRead
#
if not ALLOW_FASTPATH:
diff --git a/rpython/rlib/rstruct/test/test_pack.py
b/rpython/rlib/rstruct/test/test_pack.py
--- a/rpython/rlib/rstruct/test/test_pack.py
+++ b/rpython/rlib/rstruct/test/test_pack.py
@@ -2,8 +2,10 @@
from rpython.rlib.rarithmetic import r_ulonglong
from rpython.rlib.rstruct import standardfmttable, nativefmttable
from rpython.rlib.rstruct.error import StructOverflowError
+from rpython.rlib import buffer
from rpython.rlib.buffer import SubBuffer
from rpython.rlib.mutbuffer import MutableStringBuffer
+from rpython.rlib import rawstorage
import struct
class FakeFormatIter(object):
@@ -40,16 +42,19 @@
USE_FASTPATH = True
ALLOW_SLOWPATH = True
ALLOW_FASTPATH = True
+ ALLOW_UNALIGNED_ACCESS = rawstorage.misaligned_is_fine
def setup_method(self, meth):
standardfmttable.USE_FASTPATH = self.USE_FASTPATH
standardfmttable.ALLOW_SLOWPATH = self.ALLOW_SLOWPATH
standardfmttable.ALLOW_FASTPATH = self.ALLOW_FASTPATH
+ buffer.ALLOW_UNALIGNED_ACCESS = self.ALLOW_UNALIGNED_ACCESS
def teardown_method(self, meth):
standardfmttable.USE_FASTPATH = True
standardfmttable.ALLOW_SLOWPATH = True
standardfmttable.ALLOW_FASTPATH = True
+ buffer.ALLOW_UNALIGNED_ACCESS = rawstorage.misaligned_is_fine
def mypack(self, fmt, value):
size = struct.calcsize(fmt)
@@ -202,6 +207,7 @@
class TestUnaligned(PackSupport):
ALLOW_FASTPATH = False
+ ALLOW_UNALIGNED_ACCESS = False
bigendian = nativefmttable.native_is_bigendian
fmttable = nativefmttable.native_fmttable
@@ -227,6 +233,6 @@
wbuf.setitem(0, chr(0xAB))
wbuf.setitem(1, chr(0xCD))
fake_fmtiter = self.mypack_into('i', wsubbuf, 0x1234)
- assert fake_fmtiter.pos == wbuf.getlength()
+ assert fake_fmtiter.pos == wbuf.getlength()-2 # -2 since it's a
SubBuffer
got = wbuf.finish()
assert got == expected
_______________________________________________
pypy-commit mailing list
[email protected]
https://mail.python.org/mailman/listinfo/pypy-commit
