def test_parse_complex_cfg():
src_to_test = """
int main()
{
if(true){
test = 1;
}
var = 0;
if(true){
if(true){
test = 2;
}else{
test = 3;
}
}else{
test = 3;
}
}
"""
src_to_test_ast = parser.parse(src_to_test)
main_ast = cast_lib.find_funcdef_node(src_to_test_ast, 'main')
codecfg = cfg.ControlFlowGraph(main_ast)
#codecfg.draw()
assert len(codecfg.nodes()) == 16
assert len(codecfg.edges()) == 18
assert nx.is_directed_acyclic_graph(codecfg)
assert_degrees(codecfg, 3)
def test_parse_while_no_loop():
src_to_test = """
int main(){
while(true){
if(true){
test = 2;
}
var = 0;
}
}
"""
src_to_test_ast = parser.parse(src_to_test)
main_ast = cast_lib.find_funcdef_node(src_to_test_ast, 'main')
codecfg = cfg.ControlFlowGraph(main_ast, loop=False)
#codecfg.draw()
assert len(codecfg.nodes()) == 9
assert len(codecfg.edges()) == 10
assert nx.is_directed_acyclic_graph(codecfg)
assert_degrees(codecfg, 2)
def get_compho_update(round_ast: c_ast.Node, round_syncvar, round_label):
# remove all send() calls
cast_lib.filter_nodes(round_ast, is_send_call)
# remove round syncvar assigment to the same sync round because is redundant
cast_lib.filter_nodes(round_ast, is_round_assigment, round_syncvar,
round_label)
# move mbox = havoc() to the meta round
mbox_assigments = cast_lib.find_nodes(round_ast, is_mbox_assigment)
current_mbox = mbox_assigments[0]
round_ast.ext.insert(0, current_mbox)
main_funcdef = cast_lib.find_funcdef_node(round_ast, 'main')
cast_lib.filter_nodes(main_funcdef, is_mbox_assigment)
def test_parse_simple_cfg():
src_to_test = """
int main(){
while(true){
if(true){
test = 2;
}
var = 0;
}
}
"""
src_to_test_ast = parser.parse(src_to_test)
main_ast = cast_lib.find_funcdef_node(src_to_test_ast, 'main')
codecfg = cfg.ControlFlowGraph(main_ast)
#codecfg.draw()
assert len(codecfg.nodes()) == 9
assert len(codecfg.edges()) == 10
assert_degrees(codecfg, 1)
def prune_equivalent_paths(ast: c_ast.Node):
theory = C99Theory(ast)
code_ast = cast_lib.find_funcdef_node(ast, 'main')
code_cfg = cfg.ControlFlowGraph(code_ast, loop=False)
# collect the paths
to_visit = phase_paths(code_cfg)
# we split paths between mbox assignments and phase changes
splitted_paths = []
for p in to_visit:
splitted_path = []
chunk = []
for n_index, node in enumerate(p):
chunk.append(node)
phase_incremented = cast_lib.is_var_increment(node.astnode, 'view')
phase_jump = cast_lib.is_var_assignment(node.astnode, 'view')
path_end = type(node.astnode) == c_ast.Continue
if (phase_incremented or phase_jump
or path_end) and len(chunk) > 0:
# add context from previous chunk
if len(splitted_path) > 0:
previous_chunk = splitted_path[-1]
context_chunk = []
# we look for all asserts from the last elemento to the first mbox assignment
for n_prev in previous_chunk[::-1]:
if cast_lib.is_var_assignment(n_prev.astnode, 'mbox'):
break
if type(n_prev) == cfg.ControlFlowGraph.AssertNode:
context_chunk.insert(0, n_prev)
context_chunk.extend(chunk)
chunk = context_chunk
splitted_path.append(chunk)
chunk = []
splitted_paths.append(splitted_path)
# search for equivalent paths respecting the phase
final_paths = [path[1] for path in splitted_paths]
# BFS search of chunk equivalence
max_splitted_path = max(splitted_paths, key=lambda i: len(i))
max_splitted_path_length = len(max_splitted_path)
for depth in range(0, max_splitted_path_length):
for path_split in splitted_paths:
if len(path_split) > depth:
chunk = path_split[depth]
# look for an equivalent phase
phi = PhaseFormula(theory, chunk)
unique = True
for p in final_paths:
if p != chunk:
phi_prime = PhaseFormula(theory, p)
if phi == phi_prime:
unique = False
break
if unique:
final_paths.append(chunk)
def async_to_sync(async_ast: c_ast.Node, config):
""" Given a c99 code in a AST form, returns the corresponding code of its
synchronous equivalent program.
Notes
-----
First step is calculate all code between round variables assigments, then
we add all the context needed to reach that piece of code.
Entry point if ... if ... Current round Next round
* --------------------------------> *----------------------> *
A B
The code we want to extract is in path B, but we need to collect all the
conditions to reach this path, this is obtained collection all c_ast.If
in path A.
Path A and B can't contain c_ast.Continue nodes. Path B can't contain other
round assigments in the middle.
"""
phase_variable = config['phase']
round_variable = config['round']
labels = config['labels']
# we discard what we won't use
main_ast = cast_lib.find_funcdef_node(async_ast, 'main')
cast_lib.map_dfs(main_ast, cast_lib.replace_while_with_body, [])
cast_lib.filter_nodes(main_ast, remove_declarations)
codecfg = cfg.ControlFlowGraph(main_ast)
# we search paths between every (monotonically increasing) assigment of round variables
paths_between_rounds = paths_between_round_assignments(
codecfg, labels, round_variable, phase_variable)
# for every protocol's round we calculate all possible paths including its previous context (e.g., ifs conditions)
start_node = list(nx.topological_sort(codecfg))[0]
complete_paths_by_round = {}
for round_label, suffix_paths in paths_between_rounds.items():
complete_paths_by_round[round_label] = []
for suffix_path in suffix_paths:
suffix_first_node = list(nx.topological_sort(suffix_path))[0]
prefix_paths = get_cfg_paths_between_nodes(codecfg, start_node,
suffix_first_node)
cp = complete_paths(suffix_path, prefix_paths)
complete_paths_by_round[round_label].extend(cp)
# the code of a round is the (graph) union of all the complete paths found to belong to that round
# the easiest approach is to remove the nodes not included in those paths from the original code using the coord property
sync_code = {}
for round_label, paths in complete_paths_by_round.items():
round_code_cfg = cfg.ControlFlowGraph()
nodes_to_keep = set()
for p in paths:
for n in p.nodes():
nodes_to_keep.add(str(n.coord))
round_sync_code = copy.deepcopy(main_ast)
cast_lib.filter_nodes(round_sync_code, node_coord_not_in_set,
nodes_to_keep)
sync_code[round_label] = round_sync_code
# translate to CompHO
compho = {}
for round_label, ast_code in sync_code.items():
compho[round_label] = {}
ast_send = c_ast.FileAST([copy.deepcopy(ast_code)])
get_compho_send(ast_send)
ast_update = c_ast.FileAST([copy.deepcopy(ast_code)])
get_compho_update(ast_update, round_variable, round_label)
compho[round_label]['send'] = ast_send
compho[round_label]['update'] = ast_update
return compho