fix uninitialized variable breaking implicitely defined functions
[cparser] / parser.c
index 879b620..e042b89 100644 (file)
--- a/parser.c
+++ b/parser.c
 #include "adt/error.h"
 #include "adt/array.h"
 
-#define PRINT_TOKENS
+//#define PRINT_TOKENS
 //#define ABORT_ON_ERROR
 #define MAX_LOOKAHEAD 2
 //#define STRICT_C99
 
-struct environment_entry_t {
-       symbol_t      *symbol;
+typedef struct {
        declaration_t *old_declaration;
-       const void    *old_context;
-};
-
-static token_t               token;
-static token_t               lookahead_buffer[MAX_LOOKAHEAD];
-static int                   lookahead_bufpos;
-static struct obstack        environment_obstack;
-static environment_entry_t **environment_stack = NULL;
-static context_t            *context           = NULL;
-static declaration_t        *last_declaration  = NULL;
-static struct obstack        temp_obst;
-
-static type_t               *type_int        = NULL;
-static type_t               *type_const_char = NULL;
-static type_t               *type_string     = NULL;
-static type_t               *type_void       = NULL;
-static type_t               *type_size_t     = NULL;
+       symbol_t      *symbol;
+       unsigned short namespace;
+} stack_entry_t;
+
+static token_t         token;
+static token_t         lookahead_buffer[MAX_LOOKAHEAD];
+static int             lookahead_bufpos;
+static stack_entry_t  *environment_stack = NULL;
+static context_t      *global_context    = NULL;
+static context_t      *context           = NULL;
+static declaration_t  *last_declaration  = NULL;
+static declaration_t  *current_function  = NULL;
+static struct obstack  temp_obst;
+static bool            found_error;
+
+static type_t         *type_int         = NULL;
+static type_t         *type_uint        = NULL;
+static type_t         *type_long_double = NULL;
+static type_t         *type_double      = NULL;
+static type_t         *type_float       = NULL;
+static type_t         *type_const_char  = NULL;
+static type_t         *type_string      = NULL;
+static type_t         *type_void        = NULL;
+static type_t         *type_size_t      = NULL;
+static type_t         *type_ptrdiff_t   = NULL;
 
 static statement_t *parse_compound_statement(void);
 static statement_t *parse_statement(void);
@@ -115,6 +122,11 @@ static inline void *allocate_type_zero(size_t size)
        return res;
 }
 
+static inline void free_type(void *type)
+{
+       obstack_free(type_obst, type);
+}
+
 /**
  * returns the top element of the environment stack
  */
@@ -146,20 +158,17 @@ static inline const token_t *look_ahead(int num)
        return & lookahead_buffer[pos];
 }
 
-static inline void eat(token_type_t type)
-{
-       assert(token.type == type);
-       next_token();
-}
+#define eat(token_type)  do { assert(token.type == token_type); next_token(); } while(0)
 
-void error(void)
+static void error(void)
 {
+       found_error = true;
 #ifdef ABORT_ON_ERROR
        abort();
 #endif
 }
 
-void parser_print_prefix_pos(const source_position_t source_position)
+static void parser_print_prefix_pos(const source_position_t source_position)
 {
     fputs(source_position.input_name, stderr);
     fputc(':', stderr);
@@ -167,17 +176,17 @@ void parser_print_prefix_pos(const source_position_t source_position)
     fputs(": ", stderr);
 }
 
-void parser_print_error_prefix_pos(const source_position_t source_position)
+static void parser_print_error_prefix_pos(
+               const source_position_t source_position)
 {
        parser_print_prefix_pos(source_position);
        fputs("error: ", stderr);
        error();
 }
 
-void parser_print_error_prefix(void)
+static void parser_print_error_prefix(void)
 {
-       parser_print_prefix_pos(token.source_position);
-       error();
+       parser_print_error_prefix_pos(token.source_position);
 }
 
 static void parse_error(const char *message)
@@ -186,7 +195,6 @@ static void parse_error(const char *message)
        fprintf(stderr, "parse error: %s\n", message);
 }
 
-__attribute__((unused))
 static void parse_warning(const char *message)
 {
        parser_print_prefix_pos(token.source_position);
@@ -222,6 +230,28 @@ static void parse_error_expected(const char *message, ...)
        fprintf(stderr, "\n");
 }
 
+static void type_error(const char *msg, const source_position_t source_position,
+                       type_t *type)
+{
+       parser_print_error_prefix_pos(source_position);
+       fprintf(stderr, "%s, but found type ", msg);
+       print_type(type);
+       fputc('\n', stderr);
+       error();
+}
+
+static void type_error_incompatible(const char *msg,
+               const source_position_t source_position, type_t *type1, type_t *type2)
+{
+       parser_print_error_prefix_pos(source_position);
+       fprintf(stderr, "%s, incompatible types: ", msg);
+       print_type(type1);
+       fprintf(stderr, " - ");
+       print_type(type2);
+       fprintf(stderr, ")\n");
+       error();
+}
+
 static void eat_block(void)
 {
        if(token.type == '{')
@@ -299,16 +329,12 @@ static void set_context(context_t *new_context)
 {
        context = new_context;
 
-       declaration_t *declaration = new_context->declarations;
-       if(declaration != NULL) {
-               while(true) {
-                       if(declaration->next == NULL)
-                               break;
-                       declaration = declaration->next;
+       last_declaration = new_context->declarations;
+       if(last_declaration != NULL) {
+               while(last_declaration->next != NULL) {
+                       last_declaration = last_declaration->next;
                }
        }
-
-       last_declaration = declaration;
 }
 
 /**
@@ -322,51 +348,93 @@ static bool is_compatible_declaration (declaration_t *declaration,
        return declaration->type == previous->type;
 }
 
+static declaration_t *get_declaration(symbol_t *symbol, namespace_t namespace)
+{
+       declaration_t *declaration = symbol->declaration;
+       for( ; declaration != NULL; declaration = declaration->symbol_next) {
+               if(declaration->namespace == namespace)
+                       return declaration;
+       }
+
+       return NULL;
+}
+
+static const char *get_namespace_prefix(namespace_t namespace)
+{
+       switch(namespace) {
+       case NAMESPACE_NORMAL:
+               return "";
+       case NAMESPACE_UNION:
+               return "union ";
+       case NAMESPACE_STRUCT:
+               return "struct ";
+       case NAMESPACE_ENUM:
+               return "enum ";
+       }
+       panic("invalid namespace found");
+}
+
 /**
  * pushs an environment_entry on the environment stack and links the
  * corresponding symbol to the new entry
  */
-static inline declaration_t *environment_push(declaration_t *declaration,
-                                              const void *context)
+static declaration_t *environment_push(declaration_t *declaration)
 {
-       symbol_t *symbol = declaration->symbol;
-       assert(declaration != symbol->declaration);
+       symbol_t    *symbol    = declaration->symbol;
+       namespace_t  namespace = declaration->namespace;
        assert(declaration->source_position.input_name != NULL);
 
-       if(symbol->context == context) {
-               declaration_t *previous_declaration = symbol->declaration;
-               if(symbol->declaration != NULL) {
-                       if(!is_compatible_declaration(declaration, previous_declaration)) {
-                               parser_print_error_prefix_pos(declaration->source_position);
-                               fprintf(stderr, "definition of symbol '%s' with type ",
-                                       declaration->symbol->string);
-                               error();
-                               print_type(declaration->type);
-                               fputc('\n', stderr);
-                               parser_print_error_prefix_pos(
-                                               previous_declaration->source_position);
-                               fprintf(stderr, "is incompatible with previous declaration "
-                                       "of type ");
-                               print_type(previous_declaration->type);
-                               fputc('\n', stderr);
-                       }
-                       return previous_declaration;
+       /* a declaration should be only pushed once */
+       assert(declaration->parent_context == NULL);
+       declaration->parent_context = context;
+
+       declaration_t *previous_declaration = get_declaration(symbol, namespace);
+       assert(declaration != previous_declaration);
+       if(previous_declaration != NULL
+                       && previous_declaration->parent_context == context) {
+               if(!is_compatible_declaration(declaration, previous_declaration)) {
+                       parser_print_error_prefix_pos(declaration->source_position);
+                       fprintf(stderr, "definition of symbol %s%s with type ",
+                                       get_namespace_prefix(namespace), symbol->string);
+                       error();
+                       print_type(declaration->type);
+                       fputc('\n', stderr);
+                       parser_print_error_prefix_pos(
+                                       previous_declaration->source_position);
+                       fprintf(stderr, "is incompatible with previous declaration "
+                                       "of type ");
+                       print_type(previous_declaration->type);
+                       fputc('\n', stderr);
                }
+               return previous_declaration;
        }
 
-       environment_entry_t *entry
-               = obstack_alloc(&environment_obstack, sizeof(entry[0]));
-       memset(entry, 0, sizeof(entry[0]));
-
-       int top = ARR_LEN(environment_stack);
-       ARR_RESIZE(environment_stack, top + 1);
-       environment_stack[top] = entry;
+       /* remember old declaration */
+       stack_entry_t entry;
+       entry.symbol          = symbol;
+       entry.old_declaration = symbol->declaration;
+       entry.namespace       = namespace;
+       ARR_APP1(environment_stack, entry);
 
-       entry->old_declaration = symbol->declaration;
-       entry->old_context     = symbol->context;
-       entry->symbol          = symbol;
-       symbol->declaration    = declaration;
-       symbol->context        = context;
+       /* replace/add declaration into declaration list of the symbol */
+       if(symbol->declaration == NULL) {
+               symbol->declaration = declaration;
+       } else {
+               declaration_t *iter = symbol->declaration;
+               for( ; iter != NULL; iter = iter->symbol_next) {
+                       declaration_t *symbol_next = iter->symbol_next;
+                       if(symbol_next == NULL) {
+                               iter->symbol_next = declaration;
+                               assert(declaration->symbol_next == NULL);
+                               break;
+                       }
+                       if(symbol_next->namespace == namespace) {
+                               iter->symbol_next        = declaration;
+                               declaration->symbol_next = symbol_next->symbol_next;
+                               break;
+                       }
+               }
+       }
 
        return declaration;
 }
@@ -374,33 +442,154 @@ static inline declaration_t *environment_push(declaration_t *declaration,
 /**
  * pops symbols from the environment stack until @p new_top is the top element
  */
-static inline void environment_pop_to(size_t new_top)
+static void environment_pop_to(size_t new_top)
 {
-       environment_entry_t *entry = NULL;
        size_t top = ARR_LEN(environment_stack);
        size_t i;
 
+       assert(new_top <= top);
        if(new_top == top)
                return;
 
-       assert(new_top < top);
-       i = top;
-       do {
-               entry = environment_stack[i - 1];
-
-               symbol_t *symbol = entry->symbol;
+       for(i = top; i > new_top; --i) {
+               stack_entry_t *entry = & environment_stack[i - 1];
 
-               symbol->declaration = entry->old_declaration;
-               symbol->context     = entry->old_context;
+               declaration_t *old_declaration = entry->old_declaration;
+               symbol_t      *symbol          = entry->symbol;
+               namespace_t    namespace       = entry->namespace;
 
-               --i;
-       } while(i != new_top);
-       obstack_free(&environment_obstack, entry);
+               /* replace/remove declaration */
+               declaration_t *declaration = symbol->declaration;
+               assert(declaration != NULL);
+               if(declaration->namespace == namespace) {
+                       if(old_declaration == NULL) {
+                               symbol->declaration = declaration->symbol_next;
+                       } else {
+                               symbol->declaration = old_declaration;
+                               assert(old_declaration->symbol_next ==
+                                      declaration->symbol_next);
+                       }
+               } else {
+                       for(; declaration != NULL; declaration = declaration->symbol_next) {
+                               declaration_t *symbol_next = declaration->symbol_next;
+                               if(symbol_next->namespace == namespace) {
+                                       declaration->symbol_next = old_declaration;
+                                       assert(old_declaration->symbol_next
+                                               == symbol_next->symbol_next);
+                                       break;
+                               }
+                       }
+                       assert(declaration != NULL);
+               }
+       }
 
        ARR_SHRINKLEN(environment_stack, (int) new_top);
 }
 
 
+static int get_rank(const type_t *type)
+{
+       /* The C-standard allows promoting to int or unsigned int (see § 7.2.2
+        * and esp. footnote 108). However we can't fold constants (yet), so we
+        * can't decide wether unsigned int is possible, while int always works.
+        * (unsigned int would be preferable when possible... for stuff like
+        *  struct { enum { ... } bla : 4; } ) */
+       if(type->type == TYPE_ENUM)
+               return ATOMIC_TYPE_INT;
+
+       assert(type->type == TYPE_ATOMIC);
+       atomic_type_t      *atomic_type = (atomic_type_t*) type;
+       atomic_type_type_t  atype       = atomic_type->atype;
+       return atype;
+}
+
+static type_t *promote_integer(type_t *type)
+{
+       if(get_rank(type) < ATOMIC_TYPE_INT)
+               type = type_int;
+
+       return type;
+}
+
+static expression_t *create_cast_expression(expression_t *expression,
+                                            type_t *dest_type)
+{
+       unary_expression_t *cast = allocate_ast_zero(sizeof(cast[0]));
+
+       cast->expression.type     = EXPR_UNARY;
+       cast->type                = UNEXPR_CAST;
+       cast->value               = expression;
+       cast->expression.datatype = dest_type;
+
+       return (expression_t*) cast;
+}
+
+static expression_t *create_implicit_cast(expression_t *expression,
+                                          type_t *dest_type)
+{
+       assert(expression->datatype != NULL);
+       type_t *source_type = expression->datatype;
+
+       source_type = skip_typeref(source_type);
+       dest_type   = skip_typeref(dest_type);
+
+       if(expression->datatype == dest_type)
+               return expression;
+
+       if(dest_type->type == TYPE_ATOMIC) {
+               if(source_type->type != TYPE_ATOMIC)
+                       panic("casting of non-atomic types not implemented yet");
+
+               if(is_type_floating(dest_type) && !is_type_scalar(source_type)) {
+                       type_error_incompatible("can't cast types",
+                                               expression->source_position,
+                                               source_type, dest_type);
+                       return expression;
+               }
+
+               return create_cast_expression(expression, dest_type);
+       }
+       if(dest_type->type == TYPE_POINTER) {
+               if(source_type->type == TYPE_POINTER) {
+                       if(!pointers_compatible(source_type, dest_type)) {
+                               type_error_incompatible("can't implicitely cast types",
+                                               expression->source_position,
+                                               source_type, dest_type);
+                       } else {
+                               return create_cast_expression(expression, dest_type);
+                       }
+               }
+       }
+
+       panic("casting of non-atomic types not implemented yet");
+}
+
+static void semantic_assign(type_t *orig_type_left, expression_t **right,
+                            const char *context)
+{
+       type_t *orig_type_right = (*right)->datatype;
+       type_t *type_left       = skip_typeref(orig_type_left);
+       type_t *type_right      = skip_typeref(orig_type_right);
+
+       if(type_left == type_right) {
+               /* fine */
+       } else if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
+               *right = create_implicit_cast(*right, type_left);
+       } else if(type_left->type == TYPE_POINTER
+                       && type_right->type == TYPE_POINTER) {
+               /* TODO */
+       } else {
+               /* TODO: improve error message */
+               parser_print_error_prefix();
+               fprintf(stderr, "incompatible types in %s\n", context);
+               parser_print_error_prefix();
+               print_type(type_left);
+               fputs(" <- ", stderr);
+               print_type(type_right);
+               fputs("\n", stderr);
+       }
+
+}
 
 static expression_t *parse_constant_expression(void)
 {
@@ -415,9 +604,8 @@ static expression_t *parse_assignment_expression(void)
 }
 
 static void parse_compound_type_entries(void);
-static void parse_declarator(declaration_t *declaration,
-                             storage_class_t storage_class, type_t *type,
-                             int may_be_abstract);
+static declaration_t *parse_declarator(storage_class_t storage_class,
+               type_t *type, int may_be_abstract);
 static declaration_t *record_declaration(declaration_t *declaration);
 
 typedef struct declaration_specifiers_t  declaration_specifiers_t;
@@ -426,19 +614,177 @@ struct declaration_specifiers_t {
        type_t          *type;
 };
 
-static compound_type_t *find_compound_type(compound_type_t *types,
-                                           const symbol_t *symbol)
+static const char *parse_string_literals(void)
 {
-       compound_type_t *type = types;
-       for( ; type != NULL; type = type->next) {
-               if(type->symbol == symbol)
-                       return type;
+       assert(token.type == T_STRING_LITERAL);
+       const char *result = token.v.string;
+
+       next_token();
+
+       while(token.type == T_STRING_LITERAL) {
+               result = concat_strings(result, token.v.string);
+               next_token();
        }
 
-       return NULL;
+       return result;
 }
 
-static type_t *parse_compound_type_specifier(bool is_struct)
+static void parse_attributes(void)
+{
+       while(true) {
+               switch(token.type) {
+               case T___attribute__:
+                       next_token();
+
+                       expect_void('(');
+                       int depth = 1;
+                       while(depth > 0) {
+                               switch(token.type) {
+                               case T_EOF:
+                                       parse_error("EOF while parsing attribute");
+                                       break;
+                               case '(':
+                                       next_token();
+                                       depth++;
+                                       break;
+                               case ')':
+                                       next_token();
+                                       depth--;
+                                       break;
+                               default:
+                                       next_token();
+                               }
+                       }
+                       break;
+               case T_asm:
+                       next_token();
+                       expect_void('(');
+                       if(token.type != T_STRING_LITERAL) {
+                               parse_error_expected("while parsing assembler attribute",
+                                                    T_STRING_LITERAL);
+                               eat_brace();
+                               break;
+                       } else {
+                               parse_string_literals();
+                       }
+                       expect_void(')');
+                       break;
+               default:
+                       goto attributes_finished;
+               }
+       }
+
+attributes_finished:
+       ;
+}
+
+static designator_t *parse_designation(void)
+{
+       if(token.type != '[' && token.type != '.')
+               return NULL;
+
+       designator_t *result = NULL;
+       designator_t *last   = NULL;
+
+       while(1) {
+               designator_t *designator;
+               switch(token.type) {
+               case '[':
+                       designator = allocate_ast_zero(sizeof(designator[0]));
+                       next_token();
+                       designator->array_access = parse_constant_expression();
+                       expect(']');
+                       break;
+               case '.':
+                       designator = allocate_ast_zero(sizeof(designator[0]));
+                       next_token();
+                       if(token.type != T_IDENTIFIER) {
+                               parse_error_expected("problem while parsing designator",
+                                                    T_IDENTIFIER, 0);
+                               return NULL;
+                       }
+                       designator->symbol = token.v.symbol;
+                       next_token();
+                       break;
+               default:
+                       expect('=');
+                       return result;
+               }
+
+               assert(designator != NULL);
+               if(last != NULL) {
+                       last->next = designator;
+               } else {
+                       result = designator;
+               }
+               last = designator;
+       }
+}
+
+static initializer_t *parse_initializer_list(type_t *type);
+
+static initializer_t *parse_initializer(type_t *type)
+{
+       designator_t *designator = parse_designation();
+
+       initializer_t *result;
+       if(token.type == '{') {
+               result = parse_initializer_list(type);
+       } else {
+               result          = allocate_ast_zero(sizeof(result[0]));
+               result->type    = INITIALIZER_VALUE;
+               result->v.value = parse_assignment_expression();
+
+               if(type != NULL) {
+                       semantic_assign(type, &result->v.value, "initializer");
+               }
+       }
+       result->designator = designator;
+
+       return result;
+}
+
+static initializer_t *parse_initializer_list(type_t *type)
+{
+       eat('{');
+
+       /* TODO: semantic */
+       (void) type;
+
+       initializer_t *result = allocate_ast_zero(sizeof(result[0]));
+       result->type = INITIALIZER_LIST;
+
+       initializer_t *last = NULL;
+       while(1) {
+               initializer_t *initializer = parse_initializer(NULL);
+               if(last != NULL) {
+                       last->next = initializer;
+               } else {
+                       result->v.list = initializer;
+               }
+               last = initializer;
+
+               if(token.type == '}')
+                       break;
+
+               if(token.type != ',') {
+                       parse_error_expected("problem while parsing initializer list",
+                                            ',', '}', 0);
+                       eat_block();
+                       return result;
+               }
+               eat(',');
+
+               if(token.type == '}')
+                       break;
+       }
+
+       expect('}');
+
+       return result;
+}
+
+static declaration_t *parse_compound_type_specifier(bool is_struct)
 {
        if(is_struct) {
                eat(T_struct);
@@ -446,19 +792,17 @@ static type_t *parse_compound_type_specifier(bool is_struct)
                eat(T_union);
        }
 
-       symbol_t        *symbol        = NULL;
-       compound_type_t *compound_type = NULL;
+       symbol_t      *symbol      = NULL;
+       declaration_t *declaration = NULL;
 
        if(token.type == T_IDENTIFIER) {
                symbol = token.v.symbol;
                next_token();
 
-               if(context != NULL) {
-                       if(is_struct) {
-                               compound_type = find_compound_type(context->structs, symbol);
-                       } else {
-                               compound_type = find_compound_type(context->unions, symbol);
-                       }
+               if(is_struct) {
+                       declaration = get_declaration(symbol, NAMESPACE_STRUCT);
+               } else {
+                       declaration = get_declaration(symbol, NAMESPACE_UNION);
                }
        } else if(token.type != '{') {
                if(is_struct) {
@@ -472,39 +816,42 @@ static type_t *parse_compound_type_specifier(bool is_struct)
                return NULL;
        }
 
-       if(compound_type == NULL) {
-               compound_type = allocate_type_zero(sizeof(compound_type[0]));
+       if(declaration == NULL) {
+               declaration = allocate_type_zero(sizeof(declaration[0]));
 
                if(is_struct) {
-                       compound_type->type.type = TYPE_COMPOUND_STRUCT;
+                       declaration->namespace = NAMESPACE_STRUCT;
                } else {
-                       compound_type->type.type = TYPE_COMPOUND_UNION;
+                       declaration->namespace = NAMESPACE_UNION;
                }
-               compound_type->source_position = token.source_position;
-               compound_type->symbol          = symbol;
+               declaration->source_position = token.source_position;
+               declaration->symbol          = symbol;
        }
 
        if(token.type == '{') {
-               if(compound_type->defined) {
+               if(declaration->init.is_defined) {
+                       assert(symbol != NULL);
                        parser_print_error_prefix();
                        fprintf(stderr, "multiple definition of %s %s\n",
                                        is_struct ? "struct" : "union", symbol->string);
-                       compound_type->context.declarations = NULL;
+                       declaration->context.declarations = NULL;
                }
-               compound_type->defined = 1;
+               record_declaration(declaration);
+               declaration->init.is_defined = true;
 
                int         top          = environment_top();
                context_t  *last_context = context;
-               set_context(&compound_type->context);
+               set_context(& declaration->context);
 
                parse_compound_type_entries();
+               parse_attributes();
 
-               assert(context == &compound_type->context);
+               assert(context == & declaration->context);
                set_context(last_context);
                environment_pop_to(top);
        }
 
-       return (type_t*) compound_type;
+       return declaration;
 }
 
 static void parse_enum_entries(void)
@@ -533,7 +880,7 @@ static void parse_enum_entries(void)
 
                if(token.type == '=') {
                        next_token();
-                       entry->initializer = parse_constant_expression();
+                       entry->init.initializer = parse_initializer(type_int);
                }
 
                record_declaration(entry);
@@ -546,178 +893,111 @@ static void parse_enum_entries(void)
        expect_void('}');
 }
 
-static enum_type_t *find_enum_type(enum_type_t *types, const symbol_t *symbol)
-{
-       enum_type_t *type = types;
-       for( ; type != NULL; type = type->next) {
-               if(type->symbol == symbol)
-                       return type;
-       }
-
-       return NULL;
-}
-
-static type_t *parse_enum_specifier(void)
+static declaration_t *parse_enum_specifier(void)
 {
        eat(T_enum);
 
-       symbol_t    *symbol    = NULL;
-       enum_type_t *enum_type = NULL;
+       declaration_t *declaration;
+       symbol_t      *symbol;
 
        if(token.type == T_IDENTIFIER) {
                symbol = token.v.symbol;
                next_token();
 
-               if(context != NULL) {
-                       enum_type = find_enum_type(context->enums, symbol);
-               }
+               declaration = get_declaration(symbol, NAMESPACE_ENUM);
        } else if(token.type != '{') {
                parse_error_expected("problem while parsing enum type specifier",
                                     T_IDENTIFIER, '{', 0);
                return NULL;
+       } else {
+               declaration = NULL;
+               symbol      = NULL;
        }
 
-       if(enum_type == NULL) {
-               enum_type                  = allocate_type_zero(sizeof(enum_type[0]));
-               enum_type->type.type       = TYPE_ENUM;
-               enum_type->source_position = token.source_position;
-               enum_type->symbol          = symbol;
+       if(declaration == NULL) {
+               declaration = allocate_type_zero(sizeof(declaration[0]));
+
+               declaration->namespace       = NAMESPACE_ENUM;
+               declaration->source_position = token.source_position;
+               declaration->symbol          = symbol;
        }
 
        if(token.type == '{') {
-               if(enum_type->defined) {
+               if(declaration->init.is_defined) {
                        parser_print_error_prefix();
                        fprintf(stderr, "multiple definitions of enum %s\n",
                                symbol->string);
-                       enum_type->entries_begin = NULL;
-                       enum_type->entries_end   = NULL;
                }
-               enum_type->defined = 1;
-
-               declaration_t *before = last_declaration;
+               record_declaration(declaration);
+               declaration->init.is_defined = 1;
 
                parse_enum_entries();
-
-               if(before == NULL) {
-                       enum_type->entries_begin = context->declarations;
-               } else {
-                       enum_type->entries_begin = before->next;
-               }
-               enum_type->entries_end = last_declaration;
+               parse_attributes();
        }
 
-       return (type_t*) enum_type;
+       return declaration;
+}
+
+/**
+ * if a symbol is a typedef to another type, return true
+ */
+static bool is_typedef_symbol(symbol_t *symbol)
+{
+       declaration_t *declaration = get_declaration(symbol, NAMESPACE_NORMAL);
+       if(declaration == NULL
+                       || declaration->storage_class != STORAGE_CLASS_TYPEDEF)
+               return false;
+
+       return true;
 }
 
 static type_t *parse_typeof(void)
 {
        eat(T___typeof__);
 
-       type_t *result;
+       type_t *type;
 
        expect('(');
 
-       declaration_t *declaration;
-       expression_t  *expression;
+       expression_t *expression  = NULL;
 
 restart:
        switch(token.type) {
        case T___extension__:
                /* this can be a prefix to a typename or an expression */
                /* we simply eat it now. */
-               do {
-                       next_token();
-               } while(token.type == T___extension__);
-               goto restart;
-
-       case T_IDENTIFIER:
-               declaration = token.v.symbol->declaration;
-               if(declaration != NULL
-                               && declaration->storage_class == STORAGE_CLASS_TYPEDEF) {
-                       result = parse_typename();
-                       break;
-               }
-               expression = parse_expression();
-               result     = expression->datatype;
-               break;
-
-       TYPENAME_START
-               result = parse_typename();
-               break;
-
-       default:
-               expression = parse_expression();
-               result     = expression->datatype;
-               break;
-       }
-
-       expect(')');
-
-       return result;
-}
-
-static const char *parse_string_literals(void)
-{
-       assert(token.type == T_STRING_LITERAL);
-       const char *result = token.v.string;
-
-       next_token();
-
-       while(token.type == T_STRING_LITERAL) {
-               result = concat_strings(result, token.v.string);
-               next_token();
-       }
-
-       return result;
-}
-
-static void parse_attributes(void)
-{
-       while(true) {
-               switch(token.type) {
-               case T___attribute__:
+               do {
                        next_token();
+               } while(token.type == T___extension__);
+               goto restart;
 
-                       expect_void('(');
-                       int depth = 1;
-                       while(depth > 0) {
-                               switch(token.type) {
-                               case T_EOF:
-                                       parse_error("EOF while parsing attribute");
-                                       break;
-                               case '(':
-                                       next_token();
-                                       depth++;
-                                       break;
-                               case ')':
-                                       next_token();
-                                       depth--;
-                                       break;
-                               default:
-                                       next_token();
-                               }
-                       }
-                       break;
-               case T_asm:
-                       next_token();
-                       expect_void('(');
-                       if(token.type != T_STRING_LITERAL) {
-                               parse_error_expected("while parsing assembler attribute",
-                                                    T_STRING_LITERAL);
-                               eat_brace();
-                               break;
-                       } else {
-                               parse_string_literals();
-                       }
-                       expect_void(')');
-                       break;
-               default:
-                       goto attributes_finished;
+       case T_IDENTIFIER:
+               if(is_typedef_symbol(token.v.symbol)) {
+                       type = parse_typename();
+               } else {
+                       expression = parse_expression();
+                       type       = expression->datatype;
                }
+               break;
+
+       TYPENAME_START
+               type = parse_typename();
+               break;
+
+       default:
+               expression = parse_expression();
+               type       = expression->datatype;
+               break;
        }
 
-attributes_finished:
-       ;
+       expect(')');
+
+       typeof_type_t *typeof = allocate_type_zero(sizeof(typeof[0]));
+       typeof->type.type     = TYPE_TYPEOF;
+       typeof->expression    = expression;
+       typeof->typeof_type   = type;
+
+       return (type_t*) typeof;
 }
 
 typedef enum {
@@ -745,18 +1025,28 @@ static type_t *create_builtin_type(symbol_t *symbol)
        builtin_type_t *type = allocate_type_zero(sizeof(type[0]));
        type->type.type      = TYPE_BUILTIN;
        type->symbol         = symbol;
+       /* TODO... */
+       type->real_type      = type_int;
 
-       type_t *result = typehash_insert((type_t*) type);
-       if(result != (type_t*) type) {
-               obstack_free(type_obst, type);
-       }
+       return (type_t*) type;
+}
 
-       return result;
+static type_t *get_typedef_type(symbol_t *symbol)
+{
+       declaration_t *declaration = get_declaration(symbol, NAMESPACE_NORMAL);
+       if(declaration == NULL
+                       || declaration->storage_class != STORAGE_CLASS_TYPEDEF)
+               return NULL;
+
+       typedef_type_t *typedef_type = allocate_type_zero(sizeof(typedef_type[0]));
+       typedef_type->type.type    = TYPE_TYPEDEF;
+       typedef_type->declaration  = declaration;
+
+       return (type_t*) typedef_type;
 }
 
 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
 {
-       declaration_t *declaration;
        type_t        *type            = NULL;
        unsigned       type_qualifiers = 0;
        unsigned       type_specifiers = 0;
@@ -836,16 +1126,34 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                        }
                        break;
 
-               /* TODO: if type != NULL for the following rules issue an error */
-               case T_struct:
-                       type = parse_compound_type_specifier(true);
+               /* TODO: if type != NULL for the following rules should issue
+                * an error */
+               case T_struct: {
+                       compound_type_t *compound_type
+                               = allocate_type_zero(sizeof(compound_type[0]));
+                       compound_type->type.type = TYPE_COMPOUND_STRUCT;
+                       compound_type->declaration = parse_compound_type_specifier(true);
+
+                       type = (type_t*) compound_type;
                        break;
-               case T_union:
-                       type = parse_compound_type_specifier(false);
+               }
+               case T_union: {
+                       compound_type_t *compound_type
+                               = allocate_type_zero(sizeof(compound_type[0]));
+                       compound_type->type.type = TYPE_COMPOUND_UNION;
+                       compound_type->declaration = parse_compound_type_specifier(false);
+
+                       type = (type_t*) compound_type;
                        break;
-               case T_enum:
-                       type = parse_enum_specifier();
+               }
+               case T_enum: {
+                       enum_type_t *enum_type = allocate_type_zero(sizeof(enum_type[0]));
+                       enum_type->type.type   = TYPE_ENUM;
+                       enum_type->declaration = parse_enum_specifier();
+
+                       type = (type_t*) enum_type;
                        break;
+               }
                case T___typeof__:
                        type = parse_typeof();
                        break;
@@ -859,17 +1167,16 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                        parse_attributes();
                        break;
 
-               case T_IDENTIFIER:
-                       declaration = token.v.symbol->declaration;
-                       if(declaration == NULL ||
-                                       declaration->storage_class != STORAGE_CLASS_TYPEDEF) {
+               case T_IDENTIFIER: {
+                       type_t *typedef_type = get_typedef_type(token.v.symbol);
+
+                       if(typedef_type == NULL)
                                goto finish_specifiers;
-                       }
 
-                       type = declaration->type;
-                       assert(type != NULL);
                        next_token();
+                       type = typedef_type;
                        break;
+               }
 
                /* function specifier */
                default:
@@ -1008,7 +1315,7 @@ finish_specifiers:
 
        type_t *result = typehash_insert(type);
        if(newtype && result != (type_t*) type) {
-               obstack_free(type_obst, type);
+               free_type(type);
        }
 
        specifiers->type = result;
@@ -1054,20 +1361,22 @@ static declaration_t *parse_parameter(void)
 
        parse_declaration_specifiers(&specifiers);
 
-       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
-       parse_declarator(declaration, specifiers.storage_class,
-                        specifiers.type, 1);
+       declaration_t *declaration = parse_declarator(specifiers.storage_class,
+                                                     specifiers.type, 1);
+
+       /* TODO check declaration constraints for parameters */
+       if(declaration->storage_class == STORAGE_CLASS_TYPEDEF) {
+               parse_error("typedef not allowed in parameter list");
+       }
 
        return declaration;
 }
 
-static declaration_t *parse_parameters(method_type_t *type)
+static declaration_t *parse_parameters(function_type_t *type)
 {
        if(token.type == T_IDENTIFIER) {
-               symbol_t      *symbol      = token.v.symbol;
-               declaration_t *declaration = symbol->declaration;
-               if(declaration == NULL
-                               || declaration->storage_class != STORAGE_CLASS_TYPEDEF) {
+               symbol_t      *symbol = token.v.symbol;
+               if(!is_typedef_symbol(symbol)) {
                        /* TODO */
                        parse_identifier_list();
                        return NULL;
@@ -1083,11 +1392,11 @@ static declaration_t *parse_parameters(method_type_t *type)
                return NULL;
        }
 
-       declaration_t      *declarations = NULL;
-       declaration_t      *declaration;
-       declaration_t      *last_declaration = NULL;
-       method_parameter_t *parameter;
-       method_parameter_t *last_parameter = NULL;
+       declaration_t        *declarations = NULL;
+       declaration_t        *declaration;
+       declaration_t        *last_declaration = NULL;
+       function_parameter_t *parameter;
+       function_parameter_t *last_parameter = NULL;
 
        while(true) {
                switch(token.type) {
@@ -1126,7 +1435,7 @@ static declaration_t *parse_parameters(method_type_t *type)
 
 typedef enum {
        CONSTRUCT_POINTER,
-       CONSTRUCT_METHOD,
+       CONSTRUCT_FUNCTION,
        CONSTRUCT_ARRAY
 } construct_type_type_t;
 
@@ -1142,10 +1451,10 @@ struct parsed_pointer_t {
        type_qualifier_t  type_qualifiers;
 };
 
-typedef struct construct_method_type_t construct_method_type_t;
-struct construct_method_type_t {
-       construct_type_t  construct_type;
-       method_type_t    *method_type;
+typedef struct construct_function_type_t construct_function_type_t;
+struct construct_function_type_t {
+       construct_type_t    construct_type;
+       function_type_t    *function_type;
 };
 
 typedef struct parsed_array_t parsed_array_t;
@@ -1207,28 +1516,27 @@ static construct_type_t *parse_array_declarator(void)
        return (construct_type_t*) array;
 }
 
-static construct_type_t *parse_method_declarator(declaration_t *declaration)
+static construct_type_t *parse_function_declarator(declaration_t *declaration)
 {
        eat('(');
 
-       method_type_t *method_type
-               = allocate_type_zero(sizeof(method_type[0]));
-       method_type->type.type   = TYPE_METHOD;
+       function_type_t *type = allocate_type_zero(sizeof(type[0]));
+       type->type.type       = TYPE_FUNCTION;
 
-       declaration_t *parameters = parse_parameters(method_type);
+       declaration_t *parameters = parse_parameters(type);
        if(declaration != NULL) {
                declaration->context.declarations = parameters;
        }
 
-       construct_method_type_t *construct_method_type =
-               obstack_alloc(&temp_obst, sizeof(construct_method_type[0]));
-       memset(construct_method_type, 0, sizeof(construct_method_type[0]));
-       construct_method_type->construct_type.type = CONSTRUCT_METHOD;
-       construct_method_type->method_type         = method_type;
+       construct_function_type_t *construct_function_type =
+               obstack_alloc(&temp_obst, sizeof(construct_function_type[0]));
+       memset(construct_function_type, 0, sizeof(construct_function_type[0]));
+       construct_function_type->construct_type.type = CONSTRUCT_FUNCTION;
+       construct_function_type->function_type       = type;
 
        expect(')');
 
-       return (construct_type_t*) construct_method_type;
+       return (construct_type_t*) construct_function_type;
 }
 
 static construct_type_t *parse_inner_declarator(declaration_t *declaration,
@@ -1278,7 +1586,7 @@ static construct_type_t *parse_inner_declarator(declaration_t *declaration,
                construct_type_t *type;
                switch(token.type) {
                case '(':
-                       type = parse_method_declarator(declaration);
+                       type = parse_function_declarator(declaration);
                        break;
                case '[':
                        type = parse_array_declarator();
@@ -1315,20 +1623,20 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
 {
        construct_type_t *iter = construct_list;
        for( ; iter != NULL; iter = iter->next) {
-               parsed_pointer_t        *parsed_pointer;
-               parsed_array_t          *parsed_array;
-               construct_method_type_t *construct_method_type;
-               method_type_t           *method_type;
-               pointer_type_t          *pointer_type;
-               array_type_t            *array_type;
+               parsed_pointer_t          *parsed_pointer;
+               parsed_array_t            *parsed_array;
+               construct_function_type_t *construct_function_type;
+               function_type_t           *function_type;
+               pointer_type_t            *pointer_type;
+               array_type_t              *array_type;
 
                switch(iter->type) {
-               case CONSTRUCT_METHOD:
-                       construct_method_type = (construct_method_type_t*) iter;
-                       method_type           = construct_method_type->method_type;
+               case CONSTRUCT_FUNCTION:
+                       construct_function_type = (construct_function_type_t*) iter;
+                       function_type           = construct_function_type->function_type;
 
-                       method_type->result_type = type;
-                       type                     = (type_t*) method_type;
+                       function_type->result_type = type;
+                       type                       = (type_t*) function_type;
                        break;
 
                case CONSTRUCT_POINTER:
@@ -1357,7 +1665,7 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
 
                type_t *hashed_type = typehash_insert((type_t*) type);
                if(hashed_type != type) {
-                       obstack_free(type_obst, type);
+                       free_type(type);
                        type = hashed_type;
                }
        }
@@ -1365,50 +1673,52 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
        return type;
 }
 
-static void parse_declarator(declaration_t *declaration,
-                             storage_class_t storage_class, type_t *type,
-                             int may_be_abstract)
+static declaration_t *parse_declarator(storage_class_t storage_class,
+               type_t *type, int may_be_abstract)
 {
+       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
+       declaration->storage_class = storage_class;
+
        construct_type_t *construct_type
                = parse_inner_declarator(declaration, may_be_abstract);
+       declaration->type = construct_declarator_type(construct_type, type);
 
-       declaration->type         = construct_declarator_type(construct_type, type);
-       declaration->storage_class = storage_class;
        if(construct_type != NULL) {
                obstack_free(&temp_obst, construct_type);
        }
+
+       return declaration;
 }
 
 static type_t *parse_abstract_declarator(type_t *base_type)
 {
-       construct_type_t *construct_type
-               = parse_inner_declarator(NULL, 1);
-
-       if(construct_type == NULL)
-               return NULL;
+       construct_type_t *construct_type = parse_inner_declarator(NULL, 1);
 
        type_t *result = construct_declarator_type(construct_type, base_type);
-       obstack_free(&temp_obst, construct_type);
+       if(construct_type != NULL) {
+               obstack_free(&temp_obst, construct_type);
+       }
 
        return result;
 }
 
 static declaration_t *record_declaration(declaration_t *declaration)
 {
-       if(context == NULL)
-               return declaration;
+       assert(context != NULL);
 
        symbol_t *symbol = declaration->symbol;
        if(symbol != NULL) {
-               declaration_t *alias = environment_push(declaration, context);
+               declaration_t *alias = environment_push(declaration);
                if(alias != declaration)
                        return alias;
+       } else {
+               declaration->parent_context = context;
        }
 
        if(last_declaration != NULL) {
                last_declaration->next = declaration;
        } else {
-               context->declarations  = declaration;
+               context->declarations = declaration;
        }
        last_declaration = declaration;
 
@@ -1431,35 +1741,30 @@ static void parse_init_declarators(const declaration_specifiers_t *specifiers)
 {
        while(true) {
                declaration_t *ndeclaration
-                       = allocate_ast_zero(sizeof(ndeclaration[0]));
+                       = parse_declarator(specifiers->storage_class, specifiers->type, 0);
 
-               parse_declarator(ndeclaration, specifiers->storage_class,
-                                specifiers->type, 0);
                declaration_t *declaration = record_declaration(ndeclaration);
                if(token.type == '=') {
                        next_token();
 
-                       /* TODO: check that this is an allowed type (esp. no method type) */
+                       /* TODO: check that this is an allowed type (no function type) */
 
-                       if(declaration->initializer != NULL) {
+                       if(declaration->init.initializer != NULL) {
                                parser_error_multiple_definition(declaration, ndeclaration);
                        }
 
-                       if(token.type == '{') {
-                               // TODO
-                               expect_void('}');
-                       } else {
-                               declaration->initializer = parse_assignment_expression();
-                       }
+                       ndeclaration->init.initializer = parse_initializer(declaration->type);
                } else if(token.type == '{') {
-                       if(declaration->type->type != TYPE_METHOD) {
+                       if(declaration->type->type != TYPE_FUNCTION) {
                                parser_print_error_prefix();
                                fprintf(stderr, "Declarator ");
                                print_type_ext(declaration->type, declaration->symbol, NULL);
-                               fprintf(stderr, " is not a method type.\n");
+                               fprintf(stderr, " has a body but is not a function type.\n");
+                               eat_block();
+                               continue;
                        }
 
-                       if(declaration->initializer != NULL) {
+                       if(declaration->init.statement != NULL) {
                                parser_error_multiple_definition(declaration, ndeclaration);
                        }
                        if(ndeclaration != declaration) {
@@ -1474,16 +1779,21 @@ static void parse_init_declarators(const declaration_specifiers_t *specifiers)
                        /* push function parameters */
                        declaration_t *parameter = declaration->context.declarations;
                        for( ; parameter != NULL; parameter = parameter->next) {
-                               environment_push(parameter, context);
+                               environment_push(parameter);
                        }
+                       declaration_t *old_current_function = current_function;
+                       current_function                    = declaration;
 
                        statement_t *statement = parse_compound_statement();
 
+                       assert(current_function == declaration);
+                       old_current_function = current_function;
+
                        assert(context == &declaration->context);
                        set_context(last_context);
                        environment_pop_to(top);
 
-                       declaration->statement = statement;
+                       declaration->init.statement = statement;
                        return;
                }
 
@@ -1503,10 +1813,10 @@ static void parse_struct_declarators(const declaration_specifiers_t *specifiers)
                        /* TODO (bitfields) */
                } else {
                        declaration_t *declaration
-                               = allocate_ast_zero(sizeof(declaration[0]));
-                       parse_declarator(declaration, specifiers->storage_class,
-                                        specifiers->type, 1);
+                               = parse_declarator(specifiers->storage_class,
+                                                  specifiers->type, 1);
 
+                       /* TODO: check constraints for struct declarations */
                        /* TODO: check for doubled fields */
                        record_declaration(declaration);
 
@@ -1531,8 +1841,6 @@ static void parse_compound_type_entries(void)
        while(token.type != '}' && token.type != T_EOF) {
                declaration_specifiers_t specifiers;
                memset(&specifiers, 0, sizeof(specifiers));
-               /* TODO not correct as this allows storage class stuff... but only
-                * specifiers and qualifiers sould be allowed here */
                parse_declaration_specifiers(&specifiers);
 
                parse_struct_declarators(&specifiers);
@@ -1545,12 +1853,21 @@ static void parse_compound_type_entries(void)
 
 static void parse_declaration(void)
 {
+       source_position_t source_position = token.source_position;
+
        declaration_specifiers_t specifiers;
        memset(&specifiers, 0, sizeof(specifiers));
        parse_declaration_specifiers(&specifiers);
 
        if(token.type == ';') {
                next_token();
+
+               declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
+
+               declaration->type            = specifiers.type;
+               declaration->storage_class   = specifiers.storage_class;
+               declaration->source_position = source_position;
+               record_declaration(declaration);
                return;
        }
        parse_init_declarators(&specifiers);
@@ -1633,7 +1950,7 @@ static expression_t *parse_float_const(void)
        const_t *cnst = allocate_ast_zero(sizeof(cnst[0]));
 
        cnst->expression.type     = EXPR_CONST;
-       cnst->expression.datatype = type_int;
+       cnst->expression.datatype = type_double;
        cnst->v.float_value       = token.v.floatvalue;
 
        next_token();
@@ -1641,6 +1958,45 @@ static expression_t *parse_float_const(void)
        return (expression_t*) cnst;
 }
 
+static declaration_t *create_implicit_function(symbol_t *symbol,
+               const source_position_t source_position)
+{
+       function_type_t *function_type
+               = allocate_type_zero(sizeof(function_type[0]));
+
+       function_type->type.type              = TYPE_FUNCTION;
+       function_type->result_type            = type_int;
+       function_type->unspecified_parameters = true;
+
+       type_t *type = typehash_insert((type_t*) function_type);
+       if(type != (type_t*) function_type) {
+               free_type(function_type);
+       }
+
+       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
+
+       declaration->storage_class   = STORAGE_CLASS_EXTERN;
+       declaration->type            = type;
+       declaration->symbol          = symbol;
+       declaration->source_position = source_position;
+
+       /* prepend the implicit definition to the global context
+        * this is safe since the symbol wasn't declared as anything else yet
+        */
+       assert(symbol->declaration == NULL);
+
+       context_t *last_context = context;
+       context = global_context;
+
+       environment_push(declaration);
+       declaration->next     = context->declarations;
+       context->declarations = declaration;
+
+       context = last_context;
+
+       return declaration;
+}
+
 static expression_t *parse_reference(void)
 {
        reference_expression_t *ref = allocate_ast_zero(sizeof(ref[0]));
@@ -1648,28 +2004,32 @@ static expression_t *parse_reference(void)
        ref->expression.type = EXPR_REFERENCE;
        ref->symbol          = token.v.symbol;
 
-       declaration_t *declaration = ref->symbol->declaration;
+       declaration_t *declaration = get_declaration(ref->symbol, NAMESPACE_NORMAL);
+
+       source_position_t source_position = token.source_position;
        next_token();
 
        if(declaration == NULL) {
 #ifndef STRICT_C99
-               /* is it an implicitely defined function */
+               /* an implicitely defined function */
                if(token.type == '(') {
                        parser_print_prefix_pos(token.source_position);
                        fprintf(stderr, "warning: implicit declaration of function '%s'\n",
                                ref->symbol->string);
-                       /* TODO: do this correctly */
+
+                       declaration = create_implicit_function(ref->symbol,
+                                                              source_position);
+               } else
+#endif
+               {
+                       parser_print_error_prefix();
+                       fprintf(stderr, "unknown symbol '%s' found.\n", ref->symbol->string);
                        return (expression_t*) ref;
                }
-#endif
-
-               parser_print_error_prefix();
-               fprintf(stderr, "unknown symbol '%s' found.\n", ref->symbol->string);
-       } else {
-               ref->declaration         = declaration;
-               ref->expression.datatype = declaration->type;
        }
 
+       ref->declaration         = declaration;
+       ref->expression.datatype = declaration->type;
 
        return (expression_t*) ref;
 }
@@ -1678,7 +2038,7 @@ static void check_cast_allowed(expression_t *expression, type_t *dest_type)
 {
        (void) expression;
        (void) dest_type;
-       /* TODO check if cast is allowed and issue warnings/errors */
+       /* TODO check if explicit cast is allowed and issue warnings/errors */
 }
 
 static expression_t *parse_cast(void)
@@ -1734,7 +2094,6 @@ static expression_t *parse_brace_expression(void)
 {
        eat('(');
 
-       declaration_t *declaration;
        switch(token.type) {
        case '{':
                /* gcc extension: a stement expression */
@@ -1744,9 +2103,7 @@ static expression_t *parse_brace_expression(void)
        TYPE_SPECIFIERS
                return parse_cast();
        case T_IDENTIFIER:
-               declaration = token.v.symbol->declaration;
-               if(declaration != NULL &&
-                               (declaration->storage_class == STORAGE_CLASS_TYPEDEF)) {
+               if(is_typedef_symbol(token.v.symbol)) {
                        return parse_cast();
                }
        }
@@ -1783,9 +2140,9 @@ static expression_t *parse_pretty_function_keyword(void)
        return (expression_t*) expression;
 }
 
-static member_designator_t *parse_member_designators(void)
+static designator_t *parse_designator(void)
 {
-       member_designator_t *result = allocate_ast_zero(sizeof(result[0]));
+       designator_t *result = allocate_ast_zero(sizeof(result[0]));
 
        if(token.type != T_IDENTIFIER) {
                parse_error_expected("problem while parsing member designator",
@@ -1796,7 +2153,7 @@ static member_designator_t *parse_member_designators(void)
        result->symbol = token.v.symbol;
        next_token();
 
-       member_designator_t *last_designator = result;
+       designator_t *last_designator = result;
        while(true) {
                if(token.type == '.') {
                        next_token();
@@ -1806,9 +2163,8 @@ static member_designator_t *parse_member_designators(void)
                                eat_brace();
                                return NULL;
                        }
-                       member_designator_t *designator
-                               = allocate_ast_zero(sizeof(result[0]));
-                       designator->symbol = token.v.symbol;
+                       designator_t *designator = allocate_ast_zero(sizeof(result[0]));
+                       designator->symbol       = token.v.symbol;
                        next_token();
 
                        last_designator->next = designator;
@@ -1817,8 +2173,7 @@ static member_designator_t *parse_member_designators(void)
                }
                if(token.type == '[') {
                        next_token();
-                       member_designator_t *designator
-                               = allocate_ast_zero(sizeof(result[0]));
+                       designator_t *designator = allocate_ast_zero(sizeof(result[0]));
                        designator->array_access = parse_expression();
                        if(designator->array_access == NULL) {
                                eat_brace();
@@ -1848,7 +2203,23 @@ static expression_t *parse_offsetof(void)
        expect('(');
        expression->type = parse_typename();
        expect(',');
-       expression->member_designators = parse_member_designators();
+       expression->designator = parse_designator();
+       expect(')');
+
+       return (expression_t*) expression;
+}
+
+static expression_t *parse_va_arg(void)
+{
+       eat(T___builtin_va_arg);
+
+       va_arg_expression_t *expression = allocate_ast_zero(sizeof(expression[0]));
+       expression->expression.type     = EXPR_VA_ARG;
+
+       expect('(');
+       expression->arg = parse_assignment_expression();
+       expect(',');
+       expression->expression.datatype = parse_typename();
        expect(')');
 
        return (expression_t*) expression;
@@ -1886,9 +2257,10 @@ static expression_t *parse_primary_expression(void)
                return parse_pretty_function_keyword();
        case T___builtin_offsetof:
                return parse_offsetof();
+       case T___builtin_va_arg:
+               return parse_va_arg();
        case T___builtin_expect:
        case T___builtin_va_start:
-       case T___builtin_va_arg:
        case T___builtin_va_end:
                return parse_builtin_symbol();
 
@@ -1948,18 +2320,11 @@ static expression_t *parse_array_expression(unsigned precedence,
 static bool is_declaration_specifier(const token_t *token,
                                      bool only_type_specifiers)
 {
-       declaration_t *declaration;
-
        switch(token->type) {
                TYPE_SPECIFIERS
                        return 1;
                case T_IDENTIFIER:
-                       declaration = token->v.symbol->declaration;
-                       if(declaration == NULL)
-                               return 0;
-                       if(declaration->storage_class != STORAGE_CLASS_TYPEDEF)
-                               return 0;
-                       return 1;
+                       return is_typedef_symbol(token->v.symbol);
                STORAGE_CLASSES
                TYPE_QUALIFIERS
                        if(only_type_specifiers)
@@ -2023,9 +2388,26 @@ static expression_t *parse_call_expression(unsigned precedence,
 {
        (void) precedence;
        call_expression_t *call = allocate_ast_zero(sizeof(call[0]));
+       call->expression.type   = EXPR_CALL;
+       call->function          = expression;
 
-       call->expression.type     = EXPR_CALL;
-       call->method              = expression;
+       function_type_t *function_type;
+       type_t          *type = expression->datatype;
+       if(type->type != TYPE_FUNCTION) {
+               /* TODO calling pointers to functions is ok */
+               parser_print_error_prefix();
+               fputs("called object '", stderr);
+               print_expression(expression);
+               fputs("' (type ", stderr);
+               print_type(type);
+               fputs("is not a function\n", stderr);
+
+               function_type             = NULL;
+               call->expression.datatype = NULL;
+       } else {
+               function_type             = (function_type_t*) type;
+               call->expression.datatype = function_type->result_type;
+       }
 
        /* parse arguments */
        eat('(');
@@ -2051,51 +2433,50 @@ static expression_t *parse_call_expression(unsigned precedence,
        }
        expect(')');
 
-       type_t *type = expression->datatype;
-       if(type != NULL) {
-               /* we can call pointer to function */
-               if(type->type == TYPE_POINTER) {
-                       pointer_type_t *pointer = (pointer_type_t*) type;
-                       type = pointer->points_to;
+       if(function_type != NULL) {
+               function_parameter_t *parameter = function_type->parameters;
+               call_argument_t      *argument  = call->arguments;
+               for( ; parameter != NULL && argument != NULL;
+                               parameter = parameter->next, argument = argument->next) {
+                       type_t *expected_type = parameter->type;
+                       /* TODO report context in error messages */
+                       argument->expression  = create_implicit_cast(argument->expression,
+                                                                    expected_type);
                }
-
-               if(type == NULL || type->type != TYPE_METHOD) {
+               /* too few parameters */
+               if(parameter != NULL) {
                        parser_print_error_prefix();
-                       fprintf(stderr, "expected a method type for call but found type ");
-                       print_type(expression->datatype);
-                       fprintf(stderr, "\n");
-               } else {
-                       method_type_t *method_type = (method_type_t*) type;
-                       call->expression.datatype  = method_type->result_type;
+                       fprintf(stderr, "too few arguments to function '");
+                       print_expression(expression);
+                       fprintf(stderr, "'\n");
+               } else if(argument != NULL) {
+                       /* too many parameters */
+                       if(!function_type->variadic
+                                       && !function_type->unspecified_parameters) {
+                               parser_print_error_prefix();
+                               fprintf(stderr, "too many arguments to function '");
+                               print_expression(expression);
+                               fprintf(stderr, "'\n");
+                       } else {
+                               /* do default promotion */
+                               for( ; argument != NULL; argument = argument->next) {
+                                       type_t *type = argument->expression->datatype;
+
+                                       if(is_type_integer(type)) {
+                                               type = promote_integer(type);
+                                       } else if(type == type_float) {
+                                               type = type_double;
+                                       }
+                                       argument->expression
+                                               = create_implicit_cast(argument->expression, type);
+                               }
+                       }
                }
        }
 
        return (expression_t*) call;
 }
 
-static void type_error(const char *msg, const source_position_t source_position,
-                       const type_t *type)
-{
-       parser_print_error_prefix_pos(source_position);
-       fprintf(stderr, "%s, but found type ", msg);
-       print_type(type);
-       fputc('\n', stderr);
-       error();
-}
-
-static void type_error_incompatible(const char *msg,
-               const source_position_t source_position, const type_t *type1,
-               const type_t *type2)
-{
-       parser_print_error_prefix_pos(source_position);
-       fprintf(stderr, "%s, incompatible types: ", msg);
-       print_type(type1);
-       fprintf(stderr, " - ");
-       print_type(type2);
-       fprintf(stderr, ")\n");
-       error();
-}
-
 static type_t *get_type_after_conversion(const type_t *type1,
                                          const type_t *type2)
 {
@@ -2134,7 +2515,7 @@ static expression_t *parse_conditional_expression(unsigned precedence,
        if(false_type == NULL)
                return (expression_t*) conditional;
 
-       /* 6.4.15.3 */
+       /* 6.5.15.3 */
        if(true_type == false_type) {
                conditional->expression.datatype = true_type;
        } else if(is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
@@ -2169,99 +2550,333 @@ static expression_t *parse_extension(unsigned precedence)
        return parse_sub_expression(precedence);
 }
 
-#define CREATE_UNARY_EXPRESSION_PARSER(token_type, unexpression_type)     \
-static                                                                    \
-expression_t *parse_##unexpression_type(unsigned precedence)              \
-{                                                                         \
-       eat(token_type);                                                      \
-                                                                          \
-       unary_expression_t *unary_expression                                  \
-               = allocate_ast_zero(sizeof(unary_expression[0]));                 \
-       unary_expression->expression.type = EXPR_UNARY;                       \
-       unary_expression->type            = unexpression_type;                \
-       unary_expression->value           = parse_sub_expression(precedence); \
-                                                                          \
-       return (expression_t*) unary_expression;                              \
-}
-
-CREATE_UNARY_EXPRESSION_PARSER('-', UNEXPR_NEGATE)
-CREATE_UNARY_EXPRESSION_PARSER('+', UNEXPR_PLUS)
-CREATE_UNARY_EXPRESSION_PARSER('!', UNEXPR_NOT)
-CREATE_UNARY_EXPRESSION_PARSER('*', UNEXPR_DEREFERENCE)
-CREATE_UNARY_EXPRESSION_PARSER('&', UNEXPR_TAKE_ADDRESS)
-CREATE_UNARY_EXPRESSION_PARSER('~', UNEXPR_BITWISE_NEGATE)
-CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   UNEXPR_PREFIX_INCREMENT)
-CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, UNEXPR_PREFIX_DECREMENT)
-
-#define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_type, unexpression_type) \
-static                                                                        \
-expression_t *parse_##unexpression_type(unsigned precedence,                  \
-                                        expression_t *left)                   \
+static type_t *get_unexpr_arithmetic_type(const expression_t *expression)
+{
+       /* TODO */
+       return expression->datatype;
+}
+
+static type_t *get_unexpr_dereference_type(const expression_t *expression)
+{
+       type_t *expression_type = expression->datatype;
+
+       if(expression_type->type == TYPE_POINTER) {
+               pointer_type_t *pointer_type = (pointer_type_t*) expression_type;
+               return pointer_type->points_to;
+       }
+       panic("deref TODO...");
+       return NULL;
+}
+
+static type_t *get_unexpr_take_addr_type(const expression_t *expression)
+{
+       type_t *type = expression->datatype;
+       return make_pointer_type(type, 0);
+}
+
+#define CREATE_UNARY_EXPRESSION_PARSER(token_type, unexpression_type, tfunc)   \
+static expression_t *parse_##unexpression_type(unsigned precedence)            \
+{                                                                              \
+       eat(token_type);                                                           \
+                                                                               \
+       unary_expression_t *unary_expression                                       \
+               = allocate_ast_zero(sizeof(unary_expression[0]));                      \
+       unary_expression->expression.type     = EXPR_UNARY;                        \
+       unary_expression->type                = unexpression_type;                 \
+       unary_expression->value               = parse_sub_expression(precedence);  \
+       unary_expression->expression.datatype = tfunc(unary_expression->value);    \
+                                                                               \
+       return (expression_t*) unary_expression;                                   \
+}
+
+CREATE_UNARY_EXPRESSION_PARSER('-', UNEXPR_NEGATE, get_unexpr_arithmetic_type)
+CREATE_UNARY_EXPRESSION_PARSER('+', UNEXPR_PLUS,   get_unexpr_arithmetic_type)
+CREATE_UNARY_EXPRESSION_PARSER('!', UNEXPR_NOT,    get_unexpr_arithmetic_type)
+CREATE_UNARY_EXPRESSION_PARSER('*', UNEXPR_DEREFERENCE,
+                               get_unexpr_dereference_type)
+CREATE_UNARY_EXPRESSION_PARSER('&', UNEXPR_TAKE_ADDRESS,
+                               get_unexpr_take_addr_type)
+CREATE_UNARY_EXPRESSION_PARSER('~', UNEXPR_BITWISE_NEGATE,
+                               get_unexpr_arithmetic_type)
+CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   UNEXPR_PREFIX_INCREMENT,
+                               get_unexpr_arithmetic_type)
+CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, UNEXPR_PREFIX_DECREMENT,
+                               get_unexpr_arithmetic_type)
+
+#define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_type, unexpression_type, \
+                                               tfunc)                         \
+static expression_t *parse_##unexpression_type(unsigned precedence,           \
+                                               expression_t *left)            \
 {                                                                             \
        (void) precedence;                                                        \
        eat(token_type);                                                          \
                                                                               \
        unary_expression_t *unary_expression                                      \
                = allocate_ast_zero(sizeof(unary_expression[0]));                     \
-       unary_expression->expression.type = EXPR_UNARY;                           \
-       unary_expression->type            = unexpression_type;                    \
-       unary_expression->value           = left;                                 \
+       unary_expression->expression.type     = EXPR_UNARY;                       \
+       unary_expression->type                = unexpression_type;                \
+       unary_expression->value               = left;                             \
+       unary_expression->expression.datatype = tfunc(left);                      \
                                                                               \
        return (expression_t*) unary_expression;                                  \
 }
 
-CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,   UNEXPR_POSTFIX_INCREMENT)
-CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS, UNEXPR_POSTFIX_DECREMENT)
-
-#define CREATE_BINEXPR_PARSER(token_type, binexpression_type)    \
-static                                                           \
-expression_t *parse_##binexpression_type(unsigned precedence,    \
-                                         expression_t *left)     \
-{                                                                \
-       eat(token_type);                                             \
-                                                                 \
-       expression_t *right = parse_sub_expression(precedence);      \
-                                                                 \
-       binary_expression_t *binexpr                                 \
-               = allocate_ast_zero(sizeof(binexpr[0]));                 \
-       binexpr->expression.type = EXPR_BINARY;                      \
-       binexpr->type            = binexpression_type;               \
-       binexpr->left            = left;                             \
-       binexpr->right           = right;                            \
-                                                                 \
-       return (expression_t*) binexpr;                              \
-}
-
-CREATE_BINEXPR_PARSER(',', BINEXPR_COMMA)
-CREATE_BINEXPR_PARSER('*', BINEXPR_MUL)
-CREATE_BINEXPR_PARSER('/', BINEXPR_DIV)
-CREATE_BINEXPR_PARSER('%', BINEXPR_MOD)
-CREATE_BINEXPR_PARSER('+', BINEXPR_ADD)
-CREATE_BINEXPR_PARSER('-', BINEXPR_SUB)
-CREATE_BINEXPR_PARSER('<', BINEXPR_LESS)
-CREATE_BINEXPR_PARSER('>', BINEXPR_GREATER)
-CREATE_BINEXPR_PARSER('=', BINEXPR_ASSIGN)
-CREATE_BINEXPR_PARSER(T_EQUALEQUAL, BINEXPR_EQUAL)
-CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, BINEXPR_NOTEQUAL)
-CREATE_BINEXPR_PARSER(T_LESSEQUAL, BINEXPR_LESSEQUAL)
-CREATE_BINEXPR_PARSER(T_GREATEREQUAL, BINEXPR_GREATEREQUAL)
-CREATE_BINEXPR_PARSER('&', BINEXPR_BITWISE_AND)
-CREATE_BINEXPR_PARSER('|', BINEXPR_BITWISE_OR)
-CREATE_BINEXPR_PARSER('^', BINEXPR_BITWISE_XOR)
-CREATE_BINEXPR_PARSER(T_ANDAND, BINEXPR_LOGICAL_AND)
-CREATE_BINEXPR_PARSER(T_PIPEPIPE, BINEXPR_LOGICAL_OR)
-CREATE_BINEXPR_PARSER(T_LESSLESS, BINEXPR_SHIFTLEFT)
-CREATE_BINEXPR_PARSER(T_GREATERGREATER, BINEXPR_SHIFTRIGHT)
-CREATE_BINEXPR_PARSER(T_PLUSEQUAL, BINEXPR_ADD_ASSIGN)
-CREATE_BINEXPR_PARSER(T_MINUSEQUAL, BINEXPR_SUB_ASSIGN)
-CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL, BINEXPR_MUL_ASSIGN)
-CREATE_BINEXPR_PARSER(T_SLASHEQUAL, BINEXPR_DIV_ASSIGN)
-CREATE_BINEXPR_PARSER(T_PERCENTEQUAL, BINEXPR_MOD_ASSIGN)
-CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL, BINEXPR_SHIFTLEFT_ASSIGN)
-CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL, BINEXPR_SHIFTRIGHT_ASSIGN)
-CREATE_BINEXPR_PARSER(T_ANDEQUAL, BINEXPR_BITWISE_AND_ASSIGN)
-CREATE_BINEXPR_PARSER(T_PIPEEQUAL, BINEXPR_BITWISE_OR_ASSIGN)
-CREATE_BINEXPR_PARSER(T_CARETEQUAL, BINEXPR_BITWISE_XOR_ASSIGN)
+CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,   UNEXPR_POSTFIX_INCREMENT,
+                                       get_unexpr_arithmetic_type)
+CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS, UNEXPR_POSTFIX_DECREMENT,
+                                       get_unexpr_arithmetic_type)
+
+static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
+{
+       /* TODO: handle complex + imaginary types */
+
+       /* § 6.3.1.8 Usual arithmetic conversions */
+       if(type_left == type_long_double || type_right == type_long_double) {
+               return type_long_double;
+       } else if(type_left == type_double || type_right == type_double) {
+               return type_double;
+       } else if(type_left == type_float || type_right == type_float) {
+               return type_float;
+       }
+
+       type_right = promote_integer(type_right);
+       type_left  = promote_integer(type_left);
+
+       if(type_left == type_right)
+               return type_left;
+
+       bool signed_left  = is_type_signed(type_left);
+       bool signed_right = is_type_signed(type_right);
+       if(get_rank(type_left) < get_rank(type_right)) {
+               if(signed_left == signed_right || !signed_right) {
+                       return type_right;
+               } else {
+                       return type_left;
+               }
+       } else {
+               if(signed_left == signed_right || !signed_left) {
+                       return type_left;
+               } else {
+                       return type_right;
+               }
+       }
+}
+
+static void semantic_binexpr_arithmetic(binary_expression_t *expression)
+{
+       expression_t *left       = expression->left;
+       expression_t *right      = expression->right;
+       type_t       *type_left  = skip_typeref(left->datatype);
+       type_t       *type_right = skip_typeref(right->datatype);
+
+       if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
+               /* TODO: improve error message */
+               parser_print_error_prefix();
+               fprintf(stderr, "operation needs arithmetic types\n");
+               return;
+       }
+
+       type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
+       expression->left  = create_implicit_cast(left, arithmetic_type);
+       expression->right = create_implicit_cast(right, arithmetic_type);
+       expression->expression.datatype = arithmetic_type;
+}
+
+static void semantic_add(binary_expression_t *expression)
+{
+       expression_t *left            = expression->left;
+       expression_t *right           = expression->right;
+       type_t       *orig_type_left  = left->datatype;
+       type_t       *orig_type_right = right->datatype;
+       type_t       *type_left       = skip_typeref(orig_type_left);
+       type_t       *type_right      = skip_typeref(orig_type_right);
+
+       /* § 5.6.5 */
+       if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
+               type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
+               expression->left  = create_implicit_cast(left, arithmetic_type);
+               expression->right = create_implicit_cast(right, arithmetic_type);
+               expression->expression.datatype = arithmetic_type;
+               return;
+       } else if(type_left->type == TYPE_POINTER && is_type_integer(type_right)) {
+               expression->expression.datatype = type_left;
+       } else if(type_right->type == TYPE_POINTER && is_type_integer(type_left)) {
+               expression->expression.datatype = type_right;
+       } else {
+               parser_print_error_prefix();
+               fprintf(stderr, "invalid operands to binary + (");
+               print_type(orig_type_left);
+               fprintf(stderr, ", ");
+               print_type(orig_type_right);
+               fprintf(stderr, ")\n");
+       }
+}
+
+static void semantic_sub(binary_expression_t *expression)
+{
+       expression_t *left            = expression->left;
+       expression_t *right           = expression->right;
+       type_t       *orig_type_left  = left->datatype;
+       type_t       *orig_type_right = right->datatype;
+       type_t       *type_left       = skip_typeref(orig_type_left);
+       type_t       *type_right      = skip_typeref(orig_type_right);
+
+       /* § 5.6.5 */
+       if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
+               type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
+               expression->left  = create_implicit_cast(left, arithmetic_type);
+               expression->right = create_implicit_cast(right, arithmetic_type);
+               expression->expression.datatype = arithmetic_type;
+               return;
+       } else if(type_left->type == TYPE_POINTER && is_type_integer(type_right)) {
+               expression->expression.datatype = type_left;
+       } else if(type_left->type == TYPE_POINTER &&
+                       type_right->type == TYPE_POINTER) {
+               if(!pointers_compatible(type_left, type_right)) {
+                       parser_print_error_prefix();
+                       fprintf(stderr, "pointers to incompatible objects to binary - (");
+                       print_type(orig_type_left);
+                       fprintf(stderr, ", ");
+                       print_type(orig_type_right);
+                       fprintf(stderr, ")\n");
+               } else {
+                       expression->expression.datatype = type_ptrdiff_t;
+               }
+       } else {
+               parser_print_error_prefix();
+               fprintf(stderr, "invalid operands to binary - (");
+               print_type(orig_type_left);
+               fprintf(stderr, ", ");
+               print_type(orig_type_right);
+               fprintf(stderr, ")\n");
+       }
+}
+
+static void semantic_comparison(binary_expression_t *expression)
+{
+       expression_t *left       = expression->left;
+       expression_t *right      = expression->right;
+       type_t       *type_left  = left->datatype;
+       type_t       *type_right = right->datatype;
+
+       /* TODO non-arithmetic types */
+       if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
+               type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
+               expression->left  = create_implicit_cast(left, arithmetic_type);
+               expression->right = create_implicit_cast(right, arithmetic_type);
+               expression->expression.datatype = arithmetic_type;
+       }
+       expression->expression.datatype = type_int;
+}
+
+static void semantic_arithmetic_assign(binary_expression_t *expression)
+{
+       expression_t *left       = expression->left;
+       expression_t *right      = expression->right;
+       type_t       *type_left  = left->datatype;
+       type_t       *type_right = right->datatype;
+
+       if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
+               /* TODO: improve error message */
+               parser_print_error_prefix();
+               fprintf(stderr, "operation needs arithmetic types\n");
+               return;
+       }
+
+       /* combined instructions are tricky. We can't create an implicit cast on
+        * the left side, because we need the uncasted form for the store.
+        * The ast2firm pass has to know that left_type must be right_type
+        * for the arithmeitc operation and create a cast by itself */
+       type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
+       expression->right       = create_implicit_cast(right, arithmetic_type);
+       expression->expression.datatype = type_left;
+}
+
+static void semantic_logical_op(binary_expression_t *expression)
+{
+       /* TODO */
+       expression->expression.datatype = type_int;
+}
+
+static void semantic_binexpr_assign(binary_expression_t *expression)
+{
+       expression_t *left       = expression->left;
+       type_t       *type_left  = left->datatype;
+
+       semantic_assign(type_left, &expression->right, "assignment");
+
+       expression->expression.datatype = type_left;
+}
+
+static void semantic_comma(binary_expression_t *expression)
+{
+       expression->expression.datatype = expression->right->datatype;
+}
+
+#define CREATE_BINEXPR_PARSER(token_type, binexpression_type, sfunc, lr) \
+static expression_t *parse_##binexpression_type(unsigned precedence,     \
+                                                expression_t *left)      \
+{                                                                        \
+       eat(token_type);                                                     \
+                                                                         \
+       expression_t *right = parse_sub_expression(precedence + lr);         \
+                                                                         \
+       binary_expression_t *binexpr                                         \
+               = allocate_ast_zero(sizeof(binexpr[0]));                         \
+       binexpr->expression.type     = EXPR_BINARY;                          \
+       binexpr->type                = binexpression_type;                   \
+       binexpr->left                = left;                                 \
+       binexpr->right               = right;                                \
+       sfunc(binexpr);                                                      \
+                                                                         \
+       return (expression_t*) binexpr;                                      \
+}
+
+CREATE_BINEXPR_PARSER(',', BINEXPR_COMMA,          semantic_comma, 1)
+CREATE_BINEXPR_PARSER('*', BINEXPR_MUL,            semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER('/', BINEXPR_DIV,            semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER('%', BINEXPR_MOD,            semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER('+', BINEXPR_ADD,            semantic_add, 1)
+CREATE_BINEXPR_PARSER('-', BINEXPR_SUB,            semantic_sub, 1)
+CREATE_BINEXPR_PARSER('<', BINEXPR_LESS,           semantic_comparison, 1)
+CREATE_BINEXPR_PARSER('>', BINEXPR_GREATER,        semantic_comparison, 1)
+CREATE_BINEXPR_PARSER('=', BINEXPR_ASSIGN,         semantic_binexpr_assign, 0)
+CREATE_BINEXPR_PARSER(T_EQUALEQUAL, BINEXPR_EQUAL, semantic_comparison, 1)
+CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, BINEXPR_NOTEQUAL,
+                      semantic_comparison, 1)
+CREATE_BINEXPR_PARSER(T_LESSEQUAL, BINEXPR_LESSEQUAL, semantic_comparison, 1)
+CREATE_BINEXPR_PARSER(T_GREATEREQUAL, BINEXPR_GREATEREQUAL,
+                      semantic_comparison, 1)
+CREATE_BINEXPR_PARSER('&', BINEXPR_BITWISE_AND,    semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER('|', BINEXPR_BITWISE_OR,     semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER('^', BINEXPR_BITWISE_XOR,    semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER(T_ANDAND, BINEXPR_LOGICAL_AND,  semantic_logical_op, 1)
+CREATE_BINEXPR_PARSER(T_PIPEPIPE, BINEXPR_LOGICAL_OR, semantic_logical_op, 1)
+/* TODO shift has a bit special semantic */
+CREATE_BINEXPR_PARSER(T_LESSLESS, BINEXPR_SHIFTLEFT,
+                      semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER(T_GREATERGREATER, BINEXPR_SHIFTRIGHT,
+                      semantic_binexpr_arithmetic, 1)
+CREATE_BINEXPR_PARSER(T_PLUSEQUAL, BINEXPR_ADD_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_MINUSEQUAL, BINEXPR_SUB_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL, BINEXPR_MUL_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_SLASHEQUAL, BINEXPR_DIV_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_PERCENTEQUAL, BINEXPR_MOD_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL, BINEXPR_SHIFTLEFT_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL, BINEXPR_SHIFTRIGHT_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_ANDEQUAL, BINEXPR_BITWISE_AND_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_PIPEEQUAL, BINEXPR_BITWISE_OR_ASSIGN,
+                      semantic_arithmetic_assign, 0)
+CREATE_BINEXPR_PARSER(T_CARETEQUAL, BINEXPR_BITWISE_XOR_ASSIGN,
+                      semantic_arithmetic_assign, 0)
 
 static expression_t *parse_sub_expression(unsigned precedence)
 {
@@ -2310,8 +2925,8 @@ static expression_t *parse_expression(void)
 
 
 
-void register_expression_parser(parse_expression_function parser,
-                                int token_type, unsigned precedence)
+static void register_expression_parser(parse_expression_function parser,
+                                       int token_type, unsigned precedence)
 {
        expression_parser_function_t *entry = &expression_parsers[token_type];
 
@@ -2325,8 +2940,9 @@ void register_expression_parser(parse_expression_function parser,
        entry->precedence = precedence;
 }
 
-void register_expression_infix_parser(parse_expression_infix_function parser,
-                                      int token_type, unsigned precedence)
+static void register_expression_infix_parser(
+               parse_expression_infix_function parser, int token_type,
+               unsigned precedence)
 {
        expression_parser_function_t *entry = &expression_parsers[token_type];
 
@@ -2603,9 +3219,30 @@ static statement_t *parse_return(void)
 
        statement->statement.type            = STATEMENT_RETURN;
        statement->statement.source_position = token.source_position;
+
+       assert(current_function->type->type == TYPE_FUNCTION);
+       function_type_t *function_type = (function_type_t*) current_function->type;
+       type_t          *return_type   = function_type->result_type;
+
+       expression_t *return_value;
        if(token.type != ';') {
-               statement->return_value = parse_expression();
+               return_value = parse_expression();
+
+               if(return_type == type_void && return_value->datatype != type_void) {
+                       parse_warning("'return' with a value, in function returning void");
+                       return_value = NULL;
+               } else {
+                       semantic_assign(return_type, &return_value, "'return'");
+               }
+       } else {
+               return_value = NULL;
+               if(return_type != type_void) {
+                       parse_warning("'return' without value, in function returning "
+                                     "non-void");
+               }
        }
+       statement->return_value = return_value;
+
        expect(';');
 
        return (statement_t*) statement;
@@ -2655,7 +3292,6 @@ static statement_t *parse_expression_statement(void)
 
 static statement_t *parse_statement(void)
 {
-       declaration_t *declaration;
        statement_t   *statement = NULL;
 
        /* declaration or statement */
@@ -2719,9 +3355,7 @@ static statement_t *parse_statement(void)
                        break;
                }
 
-               declaration = token.v.symbol->declaration;
-               if(declaration != NULL &&
-                               declaration->storage_class == STORAGE_CLASS_TYPEDEF) {
+               if(is_typedef_symbol(token.v.symbol)) {
                        statement = parse_declaration_statement();
                        break;
                }
@@ -2797,6 +3431,9 @@ static translation_unit_t *parse_translation_unit(void)
 {
        translation_unit_t *unit = allocate_ast_zero(sizeof(unit[0]));
 
+       assert(global_context == NULL);
+       global_context = &unit->context;
+
        assert(context == NULL);
        set_context(&unit->context);
 
@@ -2808,15 +3445,19 @@ static translation_unit_t *parse_translation_unit(void)
        context          = NULL;
        last_declaration = NULL;
 
+       assert(global_context == &unit->context);
+       global_context = NULL;
+
        return unit;
 }
 
 translation_unit_t *parse(void)
 {
-       obstack_init(&environment_obstack);
-       environment_stack = NEW_ARR_F(environment_entry_t*, 0);
+       environment_stack = NEW_ARR_F(stack_entry_t, 0);
+       found_error       = false;
 
        type_set_output(stderr);
+       ast_set_output(stderr);
 
        lookahead_bufpos = 0;
        for(int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
@@ -2825,7 +3466,9 @@ translation_unit_t *parse(void)
        translation_unit_t *unit = parse_translation_unit();
 
        DEL_ARR_F(environment_stack);
-       obstack_free(&environment_obstack, NULL);
+
+       if(found_error)
+               return NULL;
 
        return unit;
 }
@@ -2835,11 +3478,16 @@ void init_parser(void)
        init_expression_parsers();
        obstack_init(&temp_obst);
 
-       type_int        = make_atomic_type(ATOMIC_TYPE_INT, 0);
-       type_size_t     = make_atomic_type(ATOMIC_TYPE_UINT, 0);
-       type_const_char = make_atomic_type(ATOMIC_TYPE_CHAR, TYPE_QUALIFIER_CONST);
-       type_void       = make_atomic_type(ATOMIC_TYPE_VOID, 0);
-       type_string     = make_pointer_type(type_const_char, 0);
+       type_int         = make_atomic_type(ATOMIC_TYPE_INT, 0);
+       type_uint        = make_atomic_type(ATOMIC_TYPE_UINT, 0);
+       type_long_double = make_atomic_type(ATOMIC_TYPE_LONG_DOUBLE, 0);
+       type_double      = make_atomic_type(ATOMIC_TYPE_DOUBLE, 0);
+       type_float       = make_atomic_type(ATOMIC_TYPE_FLOAT, 0);
+       type_size_t      = make_atomic_type(ATOMIC_TYPE_ULONG, 0);
+       type_ptrdiff_t   = make_atomic_type(ATOMIC_TYPE_LONG, 0);
+       type_const_char  = make_atomic_type(ATOMIC_TYPE_CHAR, TYPE_QUALIFIER_CONST);
+       type_void        = make_atomic_type(ATOMIC_TYPE_VOID, 0);
+       type_string      = make_pointer_type(type_const_char, 0);
 }
 
 void exit_parser(void)