void ansi_c_typecheckt::typecheck()
{
for(ansi_c_parse_treet::itemst::iterator
it=parse_tree.items.begin();
it!=parse_tree.items.end();
it++)
{
typecheck_declaration(*it);
}
}
void c_typecheck_baset::typecheck_decl(codet &code)
{
// this comes with 1 operand, which is a declaration
if(code.operands().size()!=1)
{
err_location(code);
error() << "decl expected to have 1 operand" << eom;
throw 0;
}
// op0 must be declaration
if(code.op0().id()!=ID_declaration)
{
err_location(code);
error() << "decl statement expected to have declaration as operand"
<< eom;
throw 0;
}
ansi_c_declarationt declaration;
declaration.swap(code.op0());
if(declaration.get_is_static_assert())
{
assert(declaration.operands().size()==2);
codet new_code(ID_static_assert);
new_code.add_source_location()=code.source_location();
new_code.operands().swap(declaration.operands());
code.swap(new_code);
typecheck_code(code);
return; // done
}
typecheck_declaration(declaration);
std::list<codet> new_code;
// iterate over declarators
for(ansi_c_declarationt::declaratorst::const_iterator
d_it=declaration.declarators().begin();
d_it!=declaration.declarators().end();
d_it++)
{
irep_idt identifier=d_it->get_name();
// look it up
symbol_tablet::symbolst::iterator s_it=
symbol_table.symbols.find(identifier);
if(s_it==symbol_table.symbols.end())
{
err_location(code);
error() << "failed to find decl symbol `" << identifier
<< "' in symbol table" << eom;
throw 0;
}
symbolt &symbol=s_it->second;
// This must not be an incomplete type, unless it's 'extern'
// or a typedef.
if(!symbol.is_type &&
!symbol.is_extern &&
!is_complete_type(symbol.type))
{
error().source_location=symbol.location;
error() << "incomplete type not permitted here" << eom;
throw 0;
}
// see if it's a typedef
// or a function
// or static
if(symbol.is_type ||
symbol.type.id()==ID_code ||
symbol.is_static_lifetime)
{
// we ignore
}
else
{
code_declt code;
code.add_source_location()=symbol.location;
code.symbol()=symbol.symbol_expr();
code.symbol().add_source_location()=symbol.location;
// add initializer, if any
if(symbol.value.is_not_nil())
{
code.operands().resize(2);
code.op1()=symbol.value;
}
new_code.push_back(code);
}
}
// stash away any side-effects in the declaration
new_code.splice(new_code.begin(), clean_code);
if(new_code.empty())
{
source_locationt source_location=code.source_location();
code=code_skipt();
code.add_source_location()=source_location;
}
else if(new_code.size()==1)
{
code.swap(new_code.front());
}
else
{
// build a decl-block
code_blockt code_block(new_code);
code_block.set_statement(ID_decl_block);
code.swap(code_block);
}
}
void c_typecheck_baset::typecheck_c_enum_type(typet &type)
{
// These come with the declarations
// of the enum constants as operands.
exprt &as_expr=static_cast<exprt &>(static_cast<irept &>(type));
source_locationt source_location=type.source_location();
// We allow empty enums in the grammar to get better
// error messages.
if(as_expr.operands().empty())
{
error().source_location=source_location;
error() << "empty enum" << eom;
throw 0;
}
// enums start at zero;
// we also track min and max to find a nice base type
mp_integer value=0, min_value=0, max_value=0;
std::list<c_enum_typet::c_enum_membert> enum_members;
// We need to determine a width, and a signedness
// to obtain an 'underlying type'.
// We just do int, but gcc might pick smaller widths
// if the type is marked as 'packed'.
// gcc/clang may also pick a larger width. Visual Studio doesn't.
for(auto &op : as_expr.operands())
{
ansi_c_declarationt &declaration=to_ansi_c_declaration(op);
exprt &v=declaration.declarator().value();
if(v.is_not_nil()) // value given?
{
exprt tmp_v=v;
typecheck_expr(tmp_v);
add_rounding_mode(tmp_v);
simplify(tmp_v, *this);
if(tmp_v.is_true())
value=1;
else if(tmp_v.is_false())
value=0;
else if(!to_integer(tmp_v, value))
{
}
else
{
error().source_location=v.source_location();
error() << "enum is not a constant";
throw 0;
}
}
if(value<min_value)
min_value=value;
if(value>max_value)
max_value=value;
typet constant_type=
enum_constant_type(min_value, max_value);
v=from_integer(value, constant_type);
declaration.type()=constant_type;
typecheck_declaration(declaration);
irep_idt base_name=
declaration.declarator().get_base_name();
irep_idt identifier=
declaration.declarator().get_name();
// store
c_enum_typet::c_enum_membert member;
member.set_identifier(identifier);
member.set_base_name(base_name);
member.set_value(integer2string(value));
enum_members.push_back(member);
// produce value for next constant
++value;
}
// Remove these now; we add them to the
// c_enum symbol later.
as_expr.operands().clear();
bool is_packed=type.get_bool(ID_C_packed);
// tag?
if(type.find(ID_tag).is_nil())
{
// None, it's anonymous. We generate a tag.
std::string anon_identifier="#anon_enum";
for(const auto &member : enum_members)
{
anon_identifier+='$';
anon_identifier+=id2string(member.get_base_name());
anon_identifier+='=';
anon_identifier+=id2string(member.get_value());
}
if(is_packed)
anon_identifier+="#packed";
type.add(ID_tag).set(ID_identifier, anon_identifier);
}
irept &tag=type.add(ID_tag);
irep_idt base_name=tag.get(ID_C_base_name);
irep_idt identifier=tag.get(ID_identifier);
// Put into symbol table
symbolt enum_tag_symbol;
enum_tag_symbol.is_type=true;
enum_tag_symbol.type=type;
enum_tag_symbol.location=source_location;
enum_tag_symbol.is_file_local=true;
enum_tag_symbol.base_name=base_name;
enum_tag_symbol.name=identifier;
// throw in the enum members as 'body'
irept::subt &body=enum_tag_symbol.type.add(ID_body).get_sub();
for(const auto &member : enum_members)
body.push_back(member);
// We use a subtype to store the underlying type.
typet underlying_type=
enum_underlying_type(min_value, max_value, is_packed);
enum_tag_symbol.type.subtype()=underlying_type;
// is it in the symbol table already?
symbol_tablet::symbolst::iterator s_it=
symbol_table.symbols.find(identifier);
if(s_it!=symbol_table.symbols.end())
{
// Yes.
symbolt &symbol=s_it->second;
if(symbol.type.id()==ID_incomplete_c_enum)
{
// Ok, overwrite the type in the symbol table.
// This gives us the members and the subtype.
symbol.type=enum_tag_symbol.type;
}
else if(symbol.type.id()==ID_c_enum)
{
// We might already have the same anonymous enum, and this is
// simply ok. Note that the C standard treats these as
// different types.
if(!base_name.empty())
{
error().source_location=type.source_location();
error() << "redeclaration of enum tag" << eom;
throw 0;
}
}
else
{
error().source_location=source_location;
error() << "use of tag that does not match previous declaration" << eom;
throw 0;
}
}
else
{
symbolt *new_symbol;
move_symbol(enum_tag_symbol, new_symbol);
}
// We produce a c_enum_tag as the resulting type.
type.id(ID_c_enum_tag);
type.remove(ID_tag);
type.set(ID_identifier, identifier);
}
