def visitExpr(self, ctx:DecafParser.ExprContext):
# Expression is a variable.
if ctx.location():
var_name = ctx.location().getText()
var_symbol = self.st.lookup(var_name)
if "[" in var_name:
split_var = var_name.split('[', 1)[0]
var_symbol = self.st.lookup(split_var)
if var_symbol == None:
print('[Error]: Variable', var_name, 'has not been declared. Found on line', ctx.start.line)
else:
var_addr = var_symbol.getAddr()
self.body += '\tmovq -' + str(var_addr[0]) + '(%rsp), %rax\n'
# Expression is a literal (number or string/char)
elif ctx.literal():
number = ctx.literal().getText()
if number == 'false':
number = '0'
if number == 'true':
number = '1'
self.body += '\tmovq $' + number + ', %rax\n'
# Expression length is more than 1 (more expressions present such as an operation)
elif len(ctx.expr()) > 1:
# Visit the first expression.
self.visit(ctx.expr(0))
# Move stack pointer 1 place and save value of first expression.
self.st.stack_pointer[-1] += 8
self.body += '\tmovq %rax, ' + str(-self.st.stack_pointer[-1]) + '(%rsp)\n'
# Visit the second expression.
self.visit(ctx.expr(1))
self.body += '\tmovq ' + str(-self.st.stack_pointer[-1]) + '(%rsp), %r10\n'
self.st.stack_pointer[-1] -= 8
self.body += '\tmovq %rax, %r11\n'
# If a binary operator is present, check the operator and add appropriate code.
if ctx.BIN_OP():
if str(ctx.BIN_OP()) == '+':
self.body += '\taddq %r10, %r11\n'
if str(ctx.BIN_OP()) == '*':
self.body += '\timul %r10, %r11\n'
if str(ctx.BIN_OP()) == '-':
self.body += '\tsubq %r10, %r11\n'
if str(ctx.BIN_OP()) == '/':
self.body += '\tmovq $0, rdx\n'
self.body += '\tmovq %r11, rbx\n'
self.body += '\tmovq %r10, rax\n'
self.body += '\tidiv %rbx\n'
self.body += '\tmovq %r11, %rax\n'
def visitExpr(self, ctx: DecafParser.ExprContext):
if ctx.literal():
int_literal = ctx.getText()
self.body += 'movq $' + int_literal + ', %rax\n'
elif ctx.location():
loc_name = ctx.getText()
location = self.st.lookup(loc_name)
addr = str(location.getAddr())
if location.mem == HEAP:
self.body += 'movq ' + addr + '(%rbp), %rax\n'
else:
self.body += 'movq ' + addr + '(%rsp), %rax\n'
else:
self.visitChildren(ctx)