A better fix for OPy determinism: add __hash__ on Block.

It now uses a deterministic integer ID instead of id(), which is based
on the memory address.

Verified that ALL bytecode in _build/oil/bytecode-opy/... is stable
across machines.

With the sorted() fix, it would pass opy-determinism-loop on
core/word_compile.py.  However, there was still nondeterminism across
machines.  This is likely due to the fact that I used sorted(), but
__cmp__ wasn't specified.

Adding __hash__ results in a process that's still deterministic, and
presumably faster than calling sorted() everywhere.

opy/compiler2/pyassem.py

@@ -120,7 +120,7 @@ def order_blocks(start_block, exit_block):
    # A block is dominated by another block if that block must be emitted
    # before it.
    dominators = {}
    for b in sorted(remaining):  # ANDY FIX: sorted() determinism
    for b in remaining:
        if __debug__ and b.next:
            assert b is b.next[0].prev[0], (b, b.next)
        # Make sure every block appears in dominators, even if no
@@ -140,8 +140,8 @@ def order_blocks(start_block, exit_block):

    def find_next():
        # Find a block that can be emitted next.
        for b in sorted(remaining):  # ANDY FIX: sorted determinism
            for c in sorted(dominators[b]):  # ditto
        for b in remaining:
            for c in dominators[b]:
                if c in remaining:
                    break # can't emit yet, dominated by a remaining block
            else:
@@ -175,6 +175,12 @@ def __init__(self, label=''):
        self.prev = []
        Block._count = Block._count + 1

    # BUG FIX: This is needed for deterministic order in sets (and dicts?).
    # See order_blocks() below.  remaining is set() of blocks.  If we rely on
    # the default id(), then the output bytecode is NONDETERMINISTIC.
    def __hash__(self):
        return self.bid

    def __repr__(self):
        if self.label:
            return "<block %s id=%d>" % (self.label, self.bid)

opy/smoke.sh

@@ -241,8 +241,8 @@ stdlib-compile() { misc/stdlib_compile.py "$@"; }
# FAILS
opy-determinism-loop() {
  #local file=../core/lexer.py
  #local file=../core/word_compile.py  # FIXED
  local file=../Python-2.7.13/Lib/genericpath.py
  local file=../core/word_compile.py  # FIXED
  #local file=../Python-2.7.13/Lib/genericpath.py
  determinism-loop opyc-compile $file
}

@@ -286,9 +286,17 @@ rebuild-and-md5() {
copy-left-right() {
  local src=flanders.local:~/git/oilshell/oil
  mkdir -p _tmp/flanders _tmp/lisa
  scp $src/_build/oil/bytecode-opy.zip $src/_tmp/flanders.pyc-md5.txt _tmp/flanders
  scp $src/_build/oil/bytecode-opy.zip $src/_tmp/pyc-md5.txt _tmp/flanders
  src=..
  cp -v $src/_build/oil/bytecode-opy.zip $src/_tmp/lisa.pyc-md5.txt _tmp/lisa
  cp -v $src/_build/oil/bytecode-opy.zip $src/_tmp/pyc-md5.txt _tmp/lisa
}

diff-left-right() {
  if diff _tmp/{lisa,flanders}/pyc-md5.txt; then
    echo SAME
  else
    echo DIFFERENT
  fi
}

unzip-left-right() {
@@ -299,7 +307,7 @@ unzip-left-right() {
  done
}

diff-left-right() {
diff-one-left-right() {
  for host in lisa flanders; do
    opyc-dis _tmp/$host/core/word_compile.pyc > _tmp/$host/word_compile.dis
  done