def compute_var_flows (nodes, outputs, preds, override_lvals_rvals = {}):
# compute a graph of reverse var flows to pass to tarjan's algorithm
graph = {}
entries = ['Ret']
for (n, node) in nodes.iteritems ():
if node.kind == 'Basic':
for (lv, rv) in node.upds:
graph[(n, 'Post', lv)] = [(n, 'Pre', v)
for v in syntax.get_expr_var_set (rv)]
elif node.is_noop ():
pass
else:
if n in override_lvals_rvals:
(lvals, rvals) = override_lvals_rvals[n]
else:
rvals = syntax.get_node_rvals (node)
rvals = set (rvals.iteritems ())
lvals = set (node.get_lvals ())
if node.kind != 'Basic':
lvals = list (lvals) + ['PC']
entries.append ((n, 'Post', 'PC'))
for lv in lvals:
graph[(n, 'Post', lv)] = [(n, 'Pre', rv)
for rv in rvals]
graph['Ret'] = [(n, 'Post', v)
for n in preds['Ret'] for v in outputs (n)]
vs = set ([v for k in graph for (_, _, v) in graph[k]])
for v in vs:
for n in nodes:
graph.setdefault ((n, 'Post', v), [(n, 'Pre', v)])
graph[(n, 'Pre', v)] = [(n2, 'Post', v)
for n2 in preds[n]]
comps = tarjan (graph, entries)
return (graph, comps)
def process_node (n, created): if p.nodes[n].is_noop (): lvals = set ([]) else: vs = syntax.get_node_rvals (p.nodes[n]) for rv in vs.iteritems (): if rv not in created: used_vs.add (rv) lvals = set (p.nodes[n].get_lvals ()) created = set.union (created, lvals) created_vs_at[n] = created visit.extend (p.nodes[n].get_conts ())
def process_node(n, created):
if p.nodes[n].is_noop():
lvals = set([])
else:
vs = syntax.get_node_rvals(p.nodes[n])
for rv in vs.iteritems():
if rv not in created:
used_vs.add(rv)
lvals = set(p.nodes[n].get_lvals())
created = set.union(created, lvals)
created_vs_at[n] = created
visit.extend(p.nodes[n].get_conts())
def compute_var_deps (nodes, outputs, preds, override_lvals_rvals = {}):
# outs = list of (outname, retvars)
var_deps = {}
visit = set ()
visit.update (preds['Ret'])
visit.update (preds['Err'])
nodes = contextual_cond_simps (nodes, preds)
while visit:
n = visit.pop ()
node = simplify_node_elementary (nodes[n])
if n in override_lvals_rvals:
(lvals, rvals) = override_lvals_rvals[n]
lvals = set (lvals)
rvals = set (rvals)
elif node.is_noop ():
lvals = set ([])
rvals = set ([])
else:
rvals = syntax.get_node_rvals (node)
rvals = set (rvals.iteritems ())
lvals = set (node.get_lvals ())
cont_vs = set ()
for c in node.get_conts ():
if c == 'Ret':
cont_vs.update (outputs (n))
elif c == 'Err':
pass
else:
cont_vs.update (var_deps.get (c, []))
vs = set.union(rvals, cont_vs - lvals)
if n in var_deps and vs <= var_deps[n]:
continue
var_deps[n] = vs
visit.update (preds[n])
return var_deps
