def _format_indirect_call_multitarget(self, branch: blocks.Branch,
uuid: int) -> str:
paths = branch.next_target_sequence()
max_index = len(paths)
paths_array_name = f'paths_{uuid}'
paths_array = self._create_target_sequence_array(
paths, paths_array_name)
func_array = self._create_call_target_array(branch.get_targets(),
f'array_{uuid}')
result = (
f'static int index_{uuid} = 0;\n'
f'{paths_array}'
f'{func_array}'
f'void (*f_{uuid})(void) = '
f'array_{uuid}[{paths_array_name}[index_{uuid}++ % {max_index}]];\n'
f'f_{uuid}();\n')
return result
def _format_branch_indirect(self, branch: blocks.Branch) -> str:
target = branch.next_valid_target()
label = self.format_code_block_label(self.code_blocks[target])
branch_id = id(branch)
fake_label = f'label{branch_id}'
result = (f'{fake_label}:;\n'
'int label_target = 0;\nvoid* array[] = {'
f'&&{label}'
f', &&{fake_label}'
'};\n'
'goto *(array[label_target]);\n')
return result
def _build_switch_cases(self, branch: blocks.Branch) -> str:
result = ''
for i in range(len(branch.targets)):
target = branch.get_target_from_index(i)
new_string = f'case {i}:\n'
if target is None:
# Fallthrough branch
new_string = f'{new_string}\tbreak;\n'
else:
label = self.format_code_block_label(self.code_blocks[target])
new_string = f'{new_string}\tgoto {label};\n'
result += new_string
return result
def _format_branch_conditional_direct(self, branch: blocks.Branch) -> str:
paths = branch.next_target_sequence()
max_index = len(paths)
branch_id = id(branch)
paths_array_name = f'paths_{branch_id}'
paths_array = self._create_target_sequence_array(
paths, paths_array_name)
switch_cases = self._build_switch_cases(branch)
result = (
f'static int index_{branch_id} = 0;\n'
f'{paths_array}'
f'switch ({paths_array_name}[index_{branch_id}++ % {max_index}]) '
'{\n'
f'{switch_cases}'
'}\n')
return result
def _format_branch_indirect_call(self,
branch: blocks.Branch,
uuid: int = None) -> str:
"""Format an indirect call.
Args:
branch: blocks.Branch instance. Must have branch_type of
INDIRECT_CALL.
uuid: Unique suffix to use for local variables. Used to
differentiate multiple branches in a single function and to avoid
any overlapping variables provided in user defined instructions.
Leaving unspecified will let the program decide a unique suffix.
Returns:
A str representing an indirect call in C.
"""
if uuid is None:
uuid = id(branch)
if len(branch.get_targets()) == 1:
return self._format_indirect_call_singletarget(branch, uuid)
return self._format_indirect_call_multitarget(branch, uuid)
def _format_branch_direct(self, branch: blocks.Branch) -> str:
target = branch.next_valid_target()
label = self.format_code_block_label(self.code_blocks[target])
return f'goto {label};\n'
def _format_branch_direct_call(self, branch: blocks.Branch) -> str:
target = branch.next_valid_target()
string = self.function_call_signature_for(target)
return f'{string}();\n'
def _format_indirect_call_singletarget(self, branch: blocks.Branch,
uuid: int) -> str:
target = branch.next_valid_target()
sig = self.function_call_signature_for(target)
return (f'void (*frontend_{uuid})(void) = {sig};\n'
f'frontend_{uuid}();\n')