def make_il(self, il_code, symbol_table, c):
""" Make code for this node """
symbol_table.new_scope()
if self.first:
self.first.make_il(il_code, symbol_table, c)
start = il_code.get_label()
cont = il_code.get_label()
end = il_code.get_label()
c = c.set_continue(cont).set_break(end)
il_code.add(control_cmds.Label(start))
with report_err():
if self.second:
cond = self.second.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.JumpZero(cond, end))
with report_err():
self.stat.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.Label(cont))
with report_err():
if self.third:
self.third.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.Jump(start))
il_code.add(control_cmds.Label(end))
symbol_table.end_scope()
def nonarith(self, left, right, il_code):
""" Check equality of non-arithmetic expressions """
# If either operand is a null pointer constant, cast it to the other's pointer type.
if left.ctype.is_pointer() and right.null_ptr_const:
right = set_type(right, left.ctype, il_code)
elif right.ctype.is_pointer() and left.null_ptr_const:
left = set_type(left, right.ctype, il_code)
# If both operands are not pointer types, quit now
if not left.ctype.is_pointer() or not right.ctype.is_pointer():
with report_err():
err = "comparison between incomparable types"
raise CompilerError(err, self.op.r)
# If one side is pointer to void, cast the other to same.
elif left.ctype.arg.is_void():
check_cast(right, left.ctype, self.op.r)
right = set_type(right, left.ctype, il_code)
elif right.ctype.arg.is_void():
check_cast(left, right.ctype, self.op.r)
left = set_type(left, right.ctype, il_code)
# If both types are still incompatible, warn!
elif not left.ctype.compatible(right.ctype):
with report_err():
err = "comparison between distinct pointer types"
raise CompilerError(err, self.op.r)
# Now, we can do comparison
out = ILValue(ctypes.integer)
il_code.add(self.eq_il_cmd(out, left, right))
return out
def parse_struct_spec(self, node, redec):
"""Parse struct ctype from the given decl_nodes.Struct node.
node (decl_nodes.Struct) - the Struct node to parse
redec (bool) - Whether this declaration is alone like so:
struct S;
or declares variables/has storage specifiers:
struct S *p;
extern struct S;
If it's the first, then this is always a forward declaration for a new `struct S` but if it's the second and a
`struct S` already exists in higher scope, it's just using the higher scope struct.
"""
has_members = node.members is not None
ctype_req = StructCType
if node.tag:
tag = str(node.tag)
ctype = self.symbol_table.lookup_struct(tag)
if ctype and not isinstance(ctype, ctype_req):
err = f"defined as wrong kind of tag '{node.kind} {tag}'"
raise CompilerError(err, node.r)
if not ctype or has_members or redec:
ctype = self.symbol_table.add_struct(tag, ctype_req(tag))
if has_members and ctype.is_complete():
err = f"redefinition of '{node.kind} {tag}'"
raise CompilerError(err, node.r)
else:
ctype = ctype_req(None)
if not has_members:
return ctype
# Struct does have members
members = []
members_set = set()
for member in node.members:
decl_infos = [] # needed in case get_decl_infos below fails
with report_err():
decl_infos = self.get_decl_infos(member)
for decl_info in decl_infos:
with report_err():
self.check_struct_member_decl_info(decl_info, node.kind,
members_set)
name = decl_info.identifier.content
members_set.add(name)
members.append((name, decl_info.ctype))
ctype.set_members(members)
return ctype
def make_il(self, il_code, symbol_table, c):
""" Make code for this declaration """
self.set_self_vars(il_code, symbol_table, c)
decl_infos = self.get_decl_infos(self.node)
for info in decl_infos:
with report_err():
info.process(il_code, symbol_table, c)
def make_il(self, il_code, symbol_table, c):
""" Make code for this node """
start = il_code.get_label()
end = il_code.get_label()
il_code.add(control_cmds.Label(start))
c = c.set_continue(start).set_break(end)
with report_err():
self.stat.make_il(il_code, symbol_table, c)
with report_err():
cond = self.cond.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.JumpZero(cond, end))
il_code.add(control_cmds.Jump(start))
il_code.add(control_cmds.Label(end))
def make_il(self, il_code, symbol_table, c):
""" Make IL code for returning this value """
label = self.get_label(c)
if label:
il_code.add(control_cmds.Jump(label))
else:
with report_err():
err = f"{self.descr} statement not in loop"
raise CompilerError(err, self.r)
def make_il(self, il_code, symbol_table, c):
""" Make code for this if statement """
endif_label = il_code.get_label()
with report_err():
cond = self.cond.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.JumpZero(cond, endif_label))
with report_err():
self.stat.make_il(il_code, symbol_table, c)
if self.else_stat:
end_label = il_code.get_label()
il_code.add(control_cmds.Jump(end_label))
il_code.add(control_cmds.Label(endif_label))
with report_err():
self.else_stat.make_il(il_code, symbol_table, c)
il_code.add(control_cmds.Label(end_label))
else:
il_code.add(control_cmds.Label(endif_label))
def make_il(self, il_code, symbol_table, c, no_scope=False):
"""Make IL code for every block item, in order. If no_scope is True, then don`t create a new symbol table scope.
Used by function definition so that parameters can live in the scope of the function body.
"""
if not no_scope:
symbol_table.new_scope()
c = c.set_global(False)
for item in self.items:
with report_err():
item.make_il(il_code, symbol_table, c)
if not no_scope:
symbol_table.end_scope()
def get_decl_infos(self, node):
"""Given a node, returns a list of decl_info objects for that node."""
any_dec = bool(node.decls)
base_type, storage = self.make_specs_ctype(node.specs, any_dec)
out = []
for decl, init in zip(node.decls, node.inits):
with report_err():
ctype, identifier = self.make_ctype(decl, base_type)
if ctype.is_function():
param_identifiers = self.extract_params(decl)
else:
param_identifiers = []
out.append(
DeclInfo(identifier, ctype, decl.r, storage, init,
self.body, param_identifiers))
return out
def make_il(self, il_code, symbol_table, c):
""" Make code for the root """
for node in self.nodes:
with report_err():
c = c.set_global(True)
node.make_il(il_code, symbol_table, c)
