public override AST.Node ToAST(Env env)
{
/// A return statement with an expression shall not appear in a function whose return type is void.
/// A return statement without an expression shall only appear in a function whose return type is void.
TFunc f = env.GetFuncType();
string returnLabel = env.GetReturnLabel();
if (expr != null)
{
if (f.ret.IsVoid)
{
throw new Error(Pos, "a return statement with an expression shall not appear a function whose return type is void");
}
AST.Expr e = expr.ToASTExpr(env).ValueTransform();
if (!Assign.SimpleAssignable(f.ret, e))
{
throw new ETypeError(Pos, string.Format("cannot assign {0} to {1}", e.Type, f.ret));
}
return(new AST.Return(returnLabel, e.ImplicitConvert(f.ret)));
}
else
{
if (!f.ret.IsVoid)
{
throw new Error(Pos, "a return statement without an expression shall only appear in a function whose return type is void");
}
return(new AST.Return(returnLabel, null));
}
}
public override AST.Node ToAST(Env env)
{
T baseType = specifiers.GetT(env);
var result = declarator.Declare(env, baseType);
if (declarations != null)
{
throw new Error(Pos, "sorry we donot support old-style function definition");
}
/// The identifier declared in a function definition (which is the name of the function) shall
/// have a function type
if (!result.Item2.IsFunc)
{
throw new ETypeError(Pos, "function definition should have function type");
}
/// The storage-class specifier, if any, shall be either extern or static.
if (specifiers.storage != StoreSpec.Kind.EXTERN &&
specifiers.storage != StoreSpec.Kind.NONE &&
specifiers.storage != StoreSpec.Kind.STATIC)
{
throw new Error(Pos, string.Format("illegal storage specifier {0} in function definition", specifiers.storage));
}
/// Determine the linkage.
var link = specifiers.storage == StoreSpec.Kind.STATIC ? SymbolEntry.Link.INTERNAL : SymbolEntry.Link.EXTERNAL;
var entry = env.GetSymbol(result.Item1);
if (entry == null)
{
/// This identifier has not been used.
env.AddFunc(result.Item1, result.Item2, link, Pos);
}
else
{
/// This identifier has been declared.
/// Check if it's a function type.
if (!entry.type.Equals(result.Item2))
{
throw new ERedefineSymbolTypeConflict(Pos, result.Item1, entry.type, result.Item2);
}
/// Check if the function has already been defined.
if (entry.type.IsDefined)
{
throw new ERedefineFunction(Pos, result.Item1);
}
/// Define the function.
entry.type.DefFunc();
}
TFunc type = result.Item2.nake as TFunc;
/// Push a new scope.
env.PushFuncScope(result.Item1, type, result.Item3, Pos);
/// Semantic check the function body.
AST.CompoundStmt b = body.ToASTCompoundStmt(env);
string returnLabel = env.GetReturnLabel();
env.PopScope();
return(new AST.FuncDef(
result.Item1,
returnLabel,
type,
result.Item3,
b,
env.ASTEnv,
specifiers.storage != StoreSpec.Kind.STATIC
));
}