def cgen_while(node):
emit_comment('cgen_while')
expr = node.ref_child[0]
stmt = node.ref_child[1]
top = ut.disFp
l1 = create_label()
l2 = create_label()
node.attribute[AttName.exit_label] = l2
emit_label(l1)
t = cgen_expr(expr)
if t.attribute[AttName.type] != Type.bool:
raise TypeError("error in node " + str(node) +
"\n type of the decision statement must be bool!")
t.attribute[AttName.address].load_address()
emit_load("$t0", "$s0")
align_stack(top)
emit("beqz $t0, " + l2)
cgen_stmt(stmt)
align_stack(top)
emit_jump(l1)
emit_label(l2)
emit_li("$t6", top)
ut.emit_add("$t6", "$t6", "$fp")
emit_move("$sp", "$t6")
return
def cgen_if2(expr, stmt):
emit_comment('cgen_if2')
l1 = create_label()
top = ut.disFp
t1 = cgen_expr(expr)
if t1.attribute[AttName.type] != Type.bool:
raise TypeError("error in node " + str(expr) +
"\n type of the decision statement must be bool!")
t1.attribute[AttName.address].load_address()
emit_load("$t0", "$s0")
align_stack(top)
emit("beqz $t0, " + l1)
cgen_stmt(stmt)
align_stack(top)
emit_label(l1)
return
def cgen_stmt_block(node):
emit_comment('cgen_stmt_block')
ut.symbolTable.add_scope()
top = ut.disFp
node.attribute[AttName.has_return] = False
for child_node in node.ref_child:
if child_node.data == "variabledecl":
cgen_variable_decl(child_node)
else:
ret = cgen_stmt(child_node)
if ret.attribute[AttName.has_return]:
node.attribute[AttName.has_return] = True
align_stack(top)
ut.symbolTable.remove_scope()
return node
def cgen_print_stmt(node):
emit_comment('cgen_print_stmt')
top = ut.disFp
for child in node.ref_child:
expr = cgen_expr(child)
address = expr.attribute[AttName.address]
type = expr.attribute[AttName.type]
address.load_address()
if type == Type.double:
emit_load_double("$f12", "$s0")
emit_li("$v0", 2)
emit_syscall()
#print_double()
elif type == "string":
emit_load("$a0", "$s0")
emit_li("$v0", 4)
emit_syscall()
elif type == Type.bool:
l1 = create_label()
l2 = create_label()
emit_load('$s0', '$s0')
emit('beqz $s0, ' + l1)
emit('la $a0, __true')
emit_jump(l2)
emit_label(l1)
emit('la $a0, __false')
emit_label(l2)
emit_li("$v0", 4)
emit_syscall()
else:
emit_load("$a0", "$s0")
emit_li("$v0", 1)
emit_syscall()
align_stack(top)
emit('la $a0, __newLine')
emit_li("$v0", 4)
emit_syscall()
def cgen_if1(expr, stmt1, stmt2):
emit_comment('cgen_if1')
l1 = create_label()
l2 = create_label()
top = ut.disFp
t1 = cgen_expr(expr)
if t1.attribute[AttName.type] != Type.bool:
raise TypeError("error in node " + str(expr) +
"\n type of the decision statement must be bool!")
t1.attribute[AttName.address].load_address()
emit_load("$t0", "$s0")
align_stack(top)
emit("beqz $t0, " + l1)
st1 = cgen_stmt(stmt1)
ret = 0
if st1.attribute[AttName.has_return]:
ret += 1
align_stack(top)
emit_jump(l2)
emit_label(l1)
st2 = cgen_stmt(stmt2)
if st2.attribute[AttName.has_return]:
ret += 1
align_stack(top)
emit_label(l2)
return ret
def cgen_stmt(node):
emit_comment('cgen_stmt')
child = node.ref_child[0]
top = ut.disFp
if child.data == "stmt":
ret = cgen_stmt(child)
node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
elif child.data == "forstmt":
cgen_for(child)
node.attribute[AttName.has_return] = False
elif child.data == "whilestmt":
cgen_while(child)
node.attribute[AttName.has_return] = False
elif child.data == "ifstmt":
ret = cgen_if(child)
node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
elif child.data == "stmtblock":
ret = cgen_stmt_block(child)
node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
elif child.data == "expr":
cgen_expr(child)
align_stack(top)
node.attribute[AttName.has_return] = False
elif child.data == "breakstmt":
cgen_break(child)
node.attribute[AttName.has_return] = False
elif child.data == "printstmt":
cgen_print_stmt(child)
node.attribute[AttName.has_return] = False
elif child.data == "returnstmt":
ret = cgen_return_stmt(child)
node.attribute[AttName.has_return] = ret
return node