def render(self, generator, op):
assert cmpopcodes.can_branch_directly(op.opname)
truelbl = generator.unique_label('load_comparision_result_true')
endlbl = generator.unique_label('load_comparision_result_end')
cmpopcodes.branch_if(generator, op.opname, truelbl)
generator.emit(jvm.ICONST, 0)
generator.goto(endlbl)
generator.mark(truelbl)
generator.emit(jvm.ICONST, 1)
generator.mark(endlbl)
def render(self, generator, op):
assert cmpopcodes.can_branch_directly(op.opname)
truelbl = generator.unique_label('load_comparision_result_true')
endlbl = generator.unique_label('load_comparision_result_end')
cmpopcodes.branch_if(generator, op.opname, truelbl)
generator.emit(jvm.ICONST, 0)
generator.goto(endlbl)
generator.mark(truelbl)
generator.emit(jvm.ICONST, 1)
generator.mark(endlbl)
def render_normal_block(self, block):
"""
Overload OOFunction.render_normal_block: we intercept blocks where the
exitcase tests a bool variable with one use so as to generate more
efficient code. For example, the naive code generation for a test
like 'if x < y' yields something like:
push x
push y
jump_if_less_than true
false:
push 0
jump done
true:
push 1
done:
store_into_local_var
load_from_local_var
jump_if_true true_destination
jump false_destination
when it could (should) be
push x
push y
jump_if_less_than true_destination
jump false_destination
"""
def not_in_link_args(v):
for link in block.exits:
if v in link.args: return False
return True
def true_false_exits():
if block.exits[0].exitcase:
return block.exits[0], block.exits[1]
return block.exits[1], block.exits[0]
if block.operations:
# Look for a case where the block switches on a bool variable
# which is produced by the last operation and not used
# anywhere else, and where the last operation is a comparison.
# Watch out for a last operation like:
# v1 = same_as([int_lt(i, j)])
last_op = block.operations[-1]
while (last_op.opname == "same_as" and
isinstance(last_op.args[0], SubOperation)):
last_op = last_op.args[0].op
if (block.exitswitch is not None and
block.exitswitch.concretetype is ootype.Bool and
block.operations[-1].result is block.exitswitch and
can_branch_directly(last_op.opname) and
not_in_link_args(block.exitswitch)):
self.generator.add_comment(
"short-circuit final comparison on %s, block has %d ops" % (
block.exitswitch, len(block.operations)))
for op in block.operations[:-1]:
self._render_op(op)
self.generator.add_comment(
"inlining comparison: %r" % (last_op),)
for arg in last_op.args:
self.ilasm.load(arg)
truelink, falselink = true_false_exits()
true_label = self.next_label('link_true')
branch_if(self.ilasm, last_op.opname, true_label)
self._follow_link(falselink)
self.set_label(true_label)
self._follow_link(truelink)
return
return OOFunction.render_normal_block(self, block)
