void c_typecheck_baset::typecheck_for(codet &code)
{
if(code.operands().size()!=4)
{
err_location(code);
error() << "for expected to have four operands" << eom;
throw 0;
}
// the "for" statement has an implicit block around it,
// since code.op0() may contain declarations
//
// we therefore transform
//
// for(a;b;c) d;
//
// to
//
// { a; for(;b;c) d; }
//
// if config.ansi_c.for_has_scope
if(!config.ansi_c.for_has_scope ||
code.op0().is_nil())
{
if(code.op0().is_not_nil())
typecheck_code(to_code(code.op0()));
if(code.op1().is_nil())
code.op1()=true_exprt();
else
{
typecheck_expr(code.op1());
implicit_typecast_bool(code.op1());
}
if(code.op2().is_not_nil())
typecheck_expr(code.op2());
if(code.op3().is_not_nil())
{
// save & set flags
bool old_break_is_allowed=break_is_allowed;
bool old_continue_is_allowed=continue_is_allowed;
break_is_allowed=continue_is_allowed=true;
// recursive call
if(to_code(code.op3()).get_statement()==ID_decl_block)
{
code_blockt code_block;
code_block.add_source_location()=code.op3().source_location();
code_block.move_to_operands(code.op3());
code.op3().swap(code_block);
}
typecheck_code(to_code(code.op3()));
// restore flags
break_is_allowed=old_break_is_allowed;
continue_is_allowed=old_continue_is_allowed;
}
}
else
{
code_blockt code_block;
code_block.add_source_location()=code.source_location();
if(to_code(code.op3()).get_statement()==ID_block)
code_block.set(
ID_C_end_location,
to_code_block(to_code(code.op3())).end_location());
else
code_block.set(
ID_C_end_location,
code.op3().source_location());;
code_block.reserve_operands(2);
code_block.move_to_operands(code.op0());
code.op0().make_nil();
code_block.move_to_operands(code);
code.swap(code_block);
typecheck_code(code); // recursive call
}
typecheck_spec_expr(code, ID_C_spec_loop_invariant);
}
