- change enum to have an underlying atomic type
[cparser] / parser.c
index baeca3a..cca652e 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -58,14 +58,14 @@ struct argument_list_t {
 
 typedef struct gnu_attribute_t gnu_attribute_t;
 struct gnu_attribute_t {
-       gnu_attribute_kind_t kind;           /**< The kind of the GNU attribute. */
+       gnu_attribute_kind_t kind;          /**< The kind of the GNU attribute. */
        gnu_attribute_t     *next;
-       bool                 invalid;        /**< Set if this attribute had argument errors, */
-       bool                 have_arguments; /**< True, if this attribute has arguments. */
+       bool                 invalid;       /**< Set if this attribute had argument errors, */
+       bool                 has_arguments; /**< True, if this attribute has arguments. */
        union {
                size_t              value;
                string_t            string;
-               atomic_type_kind_t  akind;
+               symbol_t           *symbol;
                long                argument;  /**< Single argument. */
                argument_list_t    *arguments; /**< List of argument expressions. */
        } u;
@@ -381,7 +381,6 @@ static size_t get_statement_struct_size(statement_kind_t kind)
                [STATEMENT_COMPOUND]    = sizeof(compound_statement_t),
                [STATEMENT_RETURN]      = sizeof(return_statement_t),
                [STATEMENT_DECLARATION] = sizeof(declaration_statement_t),
-               [STATEMENT_LOCAL_LABEL] = sizeof(local_label_statement_t),
                [STATEMENT_IF]          = sizeof(if_statement_t),
                [STATEMENT_SWITCH]      = sizeof(switch_statement_t),
                [STATEMENT_EXPRESSION]  = sizeof(expression_statement_t),
@@ -580,14 +579,6 @@ static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
        return result;
 }
 
-/**
- * Free a type from the type obstack.
- */
-static void free_type(void *type)
-{
-       obstack_free(type_obst, type);
-}
-
 /**
  * Returns the index of the top element of the environment stack.
  */
@@ -758,7 +749,7 @@ static void eat_block(void)
                next_token();
 }
 
-#define eat(token_type)  do { assert(token.type == (token_type)); next_token(); } while (0)
+#define eat(token_type) (assert(token.type == (token_type)), next_token())
 
 /**
  * Report a parse error because an expected token was not found.
@@ -978,13 +969,8 @@ static int get_akind_rank(atomic_type_kind_t akind)
 static int get_rank(const type_t *type)
 {
        assert(!is_typeref(type));
-       /* The C-standard allows promoting enums 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 whether unsigned int is possible, while int always works.
-        * (unsigned int would be preferable when possible... for stuff like
-        *  struct { enum { ... } bla : 4; } ) */
        if (type->kind == TYPE_ENUM)
-               return get_akind_rank(ATOMIC_TYPE_INT);
+               return get_akind_rank(type->enumt.akind);
 
        assert(type->kind == TYPE_ATOMIC);
        return get_akind_rank(type->atomic.akind);
@@ -1032,21 +1018,18 @@ static expression_t *create_cast_expression(expression_t *expression,
 static bool is_null_pointer_constant(const expression_t *expression)
 {
        /* skip void* cast */
-       if (expression->kind == EXPR_UNARY_CAST
-                       || expression->kind == EXPR_UNARY_CAST_IMPLICIT) {
-               expression = expression->unary.value;
+       if (expression->kind == EXPR_UNARY_CAST ||
+                       expression->kind == EXPR_UNARY_CAST_IMPLICIT) {
+               type_t *const type = skip_typeref(expression->base.type);
+               if (types_compatible(type, type_void_ptr))
+                       expression = expression->unary.value;
        }
 
-       /* TODO: not correct yet, should be any constant integer expression
-        * which evaluates to 0 */
-       if (expression->kind != EXPR_CONST)
-               return false;
-
        type_t *const type = skip_typeref(expression->base.type);
-       if (!is_type_integer(type))
-               return false;
-
-       return expression->conste.v.int_value == 0;
+       return
+               is_type_integer(type)              &&
+               is_constant_expression(expression) &&
+               fold_constant(expression) == 0;
 }
 
 /**
@@ -1328,7 +1311,7 @@ static gnu_attribute_t *allocate_gnu_attribute(gnu_attribute_kind_t kind)
        attribute->kind            = kind;
        attribute->next            = NULL;
        attribute->invalid         = false;
-       attribute->have_arguments  = false;
+       attribute->has_arguments   = false;
 
        return attribute;
 }
@@ -1477,35 +1460,13 @@ static void parse_gnu_attribute_model_arg(gnu_attribute_t *attribute)
  */
 static void parse_gnu_attribute_mode_arg(gnu_attribute_t *attribute)
 {
-       /* TODO: find out what is allowed here... */
-
-       /* at least: byte, word, pointer, list of machine modes
-        * __XXX___ is interpreted as XXX */
        add_anchor_token(')');
 
        if (token.type != T_IDENTIFIER) {
                expect(T_IDENTIFIER, end_error);
        }
 
-       /* This isn't really correct, the backend should provide a list of machine
-        * specific modes (according to gcc philosophy that is...) */
-       const char *symbol_str = token.v.symbol->string;
-       if (strcmp_underscore("QI",   symbol_str) == 0 ||
-           strcmp_underscore("byte", symbol_str) == 0) {
-               attribute->u.akind = ATOMIC_TYPE_CHAR;
-       } else if (strcmp_underscore("HI", symbol_str) == 0) {
-               attribute->u.akind = ATOMIC_TYPE_SHORT;
-       } else if (strcmp_underscore("SI",      symbol_str) == 0
-               || strcmp_underscore("word",    symbol_str) == 0
-               || strcmp_underscore("pointer", symbol_str) == 0) {
-               attribute->u.akind = ATOMIC_TYPE_INT;
-       } else if (strcmp_underscore("DI", symbol_str) == 0) {
-               attribute->u.akind = ATOMIC_TYPE_LONGLONG;
-       } else {
-               if (warning.other)
-                       warningf(HERE, "ignoring unknown mode '%s'", symbol_str);
-               attribute->invalid = true;
-       }
+       attribute->u.symbol = token.v.symbol;
        next_token();
 
        rem_anchor_token(')');
@@ -1591,7 +1552,7 @@ end_error:
  */
 static void check_no_argument(gnu_attribute_t *attribute, const char *name)
 {
-       if (!attribute->have_arguments)
+       if (!attribute->has_arguments)
                return;
 
        /* should have no arguments */
@@ -1741,7 +1702,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                                /* empty args are allowed */
                                                next_token();
                                        } else
-                                               attribute->have_arguments = true;
+                                               attribute->has_arguments = true;
                                }
 
                                switch (kind) {
@@ -1800,7 +1761,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
 
                                case GNU_AK_ALIGNED:
                                        /* __align__ may be used without an argument */
-                                       if (attribute->have_arguments) {
+                                       if (attribute->has_arguments) {
                                                parse_gnu_attribute_const_arg(attribute);
                                        }
                                        break;
@@ -1808,7 +1769,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                case GNU_AK_FORMAT_ARG:
                                case GNU_AK_REGPARM:
                                case GNU_AK_TRAP_EXIT:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                                attribute->invalid = true;
@@ -1818,7 +1779,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                case GNU_AK_ALIAS:
                                case GNU_AK_SECTION:
                                case GNU_AK_SP_SWITCH:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                                attribute->invalid = true;
@@ -1826,7 +1787,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                                parse_gnu_attribute_string_arg(attribute, &attribute->u.string);
                                        break;
                                case GNU_AK_FORMAT:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                                attribute->invalid = true;
@@ -1835,29 +1796,29 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                        break;
                                case GNU_AK_WEAKREF:
                                        /* may have one string argument */
-                                       if (attribute->have_arguments)
+                                       if (attribute->has_arguments)
                                                parse_gnu_attribute_string_arg(attribute, &attribute->u.string);
                                        break;
                                case GNU_AK_NONNULL:
-                                       if (attribute->have_arguments)
+                                       if (attribute->has_arguments)
                                                parse_gnu_attribute_const_arg_list(attribute);
                                        break;
                                case GNU_AK_TLS_MODEL:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                        } else
                                                parse_gnu_attribute_tls_model_arg(attribute);
                                        break;
                                case GNU_AK_VISIBILITY:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                        } else
                                                parse_gnu_attribute_visibility_arg(attribute);
                                        break;
                                case GNU_AK_MODEL:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                        } else {
@@ -1865,7 +1826,7 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                        }
                                        break;
                                case GNU_AK_MODE:
-                                       if (!attribute->have_arguments) {
+                                       if (!attribute->has_arguments) {
                                                /* should have arguments */
                                                errorf(HERE, "wrong number of arguments specified for '%s' attribute", name);
                                        } else {
@@ -1874,12 +1835,12 @@ static decl_modifiers_t parse_gnu_attribute(gnu_attribute_t **attributes)
                                        break;
                                case GNU_AK_INTERRUPT:
                                        /* may have one string argument */
-                                       if (attribute->have_arguments)
+                                       if (attribute->has_arguments)
                                                parse_gnu_attribute_interrupt_arg(attribute);
                                        break;
                                case GNU_AK_SENTINEL:
                                        /* may have one string argument */
-                                       if (attribute->have_arguments)
+                                       if (attribute->has_arguments)
                                                parse_gnu_attribute_const_arg(attribute);
                                        break;
                                case GNU_AK_LAST:
@@ -2946,7 +2907,7 @@ static initializer_t *parse_initializer(parse_initializer_env_t *env)
                result = parse_scalar_initializer(type, env->must_be_constant);
        }
 
-       /* § 6.7.8 (22) array initializers for arrays with unknown size determine
+       /* § 6.7.8:22 array initializers for arrays with unknown size determine
         * the array type size */
        if (is_type_array(type) && type->array.size_expression == NULL
                        && result != NULL) {
@@ -3033,8 +2994,8 @@ static compound_t *parse_compound_type_specifier(bool is_struct)
                        compound = &entity->compound;
                        if (compound->base.parent_scope != current_scope &&
                            (token.type == '{' || token.type == ';')) {
-                               /* we're in an inner scope and have a definition. Override
-                                  existing definition in outer scope */
+                               /* we're in an inner scope and have a definition. Shadow
+                                * existing definition in outer scope */
                                compound = NULL;
                        } else if (compound->complete && token.type == '{') {
                                assert(symbol != NULL);
@@ -3148,7 +3109,18 @@ static type_t *parse_enum_specifier(void)
                next_token();
 
                entity = get_entity(symbol, NAMESPACE_ENUM);
-               assert(entity == NULL || entity->kind == ENTITY_ENUM);
+               if (entity != NULL) {
+                       assert(entity->kind == ENTITY_ENUM);
+                       if (entity->base.parent_scope != current_scope &&
+                                       (token.type == '{' || token.type == ';')) {
+                               /* we're in an inner scope and have a definition. Shadow
+                                * existing definition in outer scope */
+                               entity = NULL;
+                       } else if (entity->enume.complete && token.type == '{') {
+                               errorf(HERE, "multiple definitions of 'enum %Y' (previous definition %P)",
+                                               symbol, &entity->base.source_position);
+                       }
+               }
        } else if (token.type != '{') {
                parse_error_expected("while parsing enum type specifier",
                                     T_IDENTIFIER, '{', NULL);
@@ -3168,12 +3140,9 @@ static type_t *parse_enum_specifier(void)
 
        type_t *const type = allocate_type_zero(TYPE_ENUM);
        type->enumt.enume  = &entity->enume;
+       type->enumt.akind  = ATOMIC_TYPE_INT;
 
        if (token.type == '{') {
-               if (entity->enume.complete) {
-                       errorf(HERE, "multiple definitions of 'enum %Y' (previous definition %P)",
-                              symbol, &entity->base.source_position);
-               }
                if (symbol != NULL) {
                        environment_push(entity);
                }
@@ -3286,13 +3255,7 @@ static type_t *create_builtin_type(symbol_t *const symbol,
        type_t *type            = allocate_type_zero(TYPE_BUILTIN);
        type->builtin.symbol    = symbol;
        type->builtin.real_type = real_type;
-
-       type_t *result = typehash_insert(type);
-       if (type != result) {
-               free_type(type);
-       }
-
-       return result;
+       return identify_new_type(type);
 }
 
 static type_t *get_typedef_type(symbol_t *symbol)
@@ -3621,6 +3584,78 @@ static void finish_union_type(compound_type_t *type)
        type->base.alignment = alignment;
 }
 
+static type_t *handle_attribute_mode(const gnu_attribute_t *attribute,
+                                     type_t *orig_type)
+{
+       type_t *type = skip_typeref(orig_type);
+
+       /* at least: byte, word, pointer, list of machine modes
+        * __XXX___ is interpreted as XXX */
+
+       /* This isn't really correct, the backend should provide a list of machine
+        * specific modes (according to gcc philosophy that is...) */
+       const char         *symbol_str = attribute->u.symbol->string;
+       bool                sign       = is_type_signed(type);
+       atomic_type_kind_t  akind;
+       if (strcmp_underscore("QI",   symbol_str) == 0 ||
+           strcmp_underscore("byte", symbol_str) == 0) {
+               akind = sign ? ATOMIC_TYPE_CHAR : ATOMIC_TYPE_UCHAR;
+       } else if (strcmp_underscore("HI", symbol_str) == 0) {
+               akind = sign ? ATOMIC_TYPE_SHORT : ATOMIC_TYPE_USHORT;
+       } else if (strcmp_underscore("SI",      symbol_str) == 0
+               || strcmp_underscore("word",    symbol_str) == 0
+               || strcmp_underscore("pointer", symbol_str) == 0) {
+               akind = sign ? ATOMIC_TYPE_INT : ATOMIC_TYPE_UINT;
+       } else if (strcmp_underscore("DI", symbol_str) == 0) {
+               akind = sign ? ATOMIC_TYPE_LONGLONG : ATOMIC_TYPE_ULONGLONG;
+       } else {
+               if (warning.other)
+                       warningf(HERE, "ignoring unknown mode '%s'", symbol_str);
+               return orig_type;
+       }
+
+       if (type->kind == TYPE_ATOMIC) {
+               type_t *copy       = duplicate_type(type);
+               copy->atomic.akind = akind;
+               return identify_new_type(copy);
+       } else if (type->kind == TYPE_ENUM) {
+               type_t *copy      = duplicate_type(type);
+               copy->enumt.akind = akind;
+               return identify_new_type(copy);
+       } else if (is_type_pointer(type)) {
+               warningf(HERE, "__attribute__((mode)) on pointers not implemented yet (ignored)");
+               return type;
+       }
+
+       errorf(HERE, "__attribute__((mode)) only allowed on integer, enum or pointer type");
+       return orig_type;
+}
+
+static type_t *handle_type_attributes(const gnu_attribute_t *attributes,
+                                      type_t *type)
+{
+       const gnu_attribute_t *attribute = attributes;
+       for ( ; attribute != NULL; attribute = attribute->next) {
+               if (attribute->invalid)
+                       continue;
+
+               if (attribute->kind == GNU_AK_MODE) {
+                       type = handle_attribute_mode(attribute, type);
+               } else if (attribute->kind == GNU_AK_ALIGNED) {
+                       int alignment = 32; /* TODO: fill in maximum useful alignment for
+                                              target machine */
+                       if (attribute->has_arguments)
+                               alignment = attribute->u.argument;
+
+                       type_t *copy         = duplicate_type(type);
+                       copy->base.alignment = attribute->u.argument;
+                       type                 = identify_new_type(copy);
+               }
+       }
+
+       return type;
+}
+
 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
 {
        type_t            *type              = NULL;
@@ -3636,8 +3671,6 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
        while (true) {
                specifiers->modifiers
                        |= parse_attributes(&specifiers->gnu_attributes);
-               if (specifiers->modifiers & DM_TRANSPARENT_UNION)
-                       modifiers |= TYPE_MODIFIER_TRANSPARENT_UNION;
 
                switch (token.type) {
                /* storage class */
@@ -3858,6 +3891,9 @@ wrong_thread_stoarge_class:
        }
 
 finish_specifiers:
+       specifiers->modifiers
+               |= parse_attributes(&specifiers->gnu_attributes);
+
        in_gcc_extension = old_gcc_extension;
 
        if (type == NULL || (saw_error && type_specifiers != 0)) {
@@ -4032,9 +4068,13 @@ warn_about_long_long:
                        type                  = allocate_type_zero(TYPE_IMAGINARY);
                        type->imaginary.akind = atomic_type;
                } else {
-                       type               = allocate_type_zero(TYPE_ATOMIC);
-                       type->atomic.akind = atomic_type;
+                       type                 = allocate_type_zero(TYPE_ATOMIC);
+                       type->atomic.akind   = atomic_type;
                }
+               type->base.alignment = get_atomic_type_alignment(atomic_type);
+               unsigned const size  = get_atomic_type_size(atomic_type);
+               type->base.size      =
+                       type_specifiers & SPECIFIER_COMPLEX ? size * 2 : size;
                newtype = true;
        } else if (type_specifiers != 0) {
                errorf(HERE, "multiple datatypes in declaration");
@@ -4042,15 +4082,15 @@ warn_about_long_long:
 
        /* FIXME: check type qualifiers here */
 
+       if (specifiers->modifiers & DM_TRANSPARENT_UNION)
+               modifiers |= TYPE_MODIFIER_TRANSPARENT_UNION;
        type->base.qualifiers = qualifiers;
        type->base.modifiers  = modifiers;
 
-       type_t *result = typehash_insert(type);
-       if (newtype && result != type) {
-               free_type(type);
-       }
+       type = identify_new_type(type);
 
-       specifiers->type = result;
+       type = handle_type_attributes(specifiers->gnu_attributes, type);
+       specifiers->type = type;
        return;
 
 end_error:
@@ -4550,34 +4590,28 @@ static void parse_declaration_attributes(entity_t *entity)
        if (type == NULL)
                return;
 
-       /* handle these strange/stupid mode attributes */
        gnu_attribute_t *attribute = attributes;
        for ( ; attribute != NULL; attribute = attribute->next) {
-               if (attribute->kind != GNU_AK_MODE || attribute->invalid)
+               if (attribute->invalid)
                        continue;
 
-               atomic_type_kind_t  akind = attribute->u.akind;
-               if (!is_type_signed(type)) {
-                       switch (akind) {
-                       case ATOMIC_TYPE_CHAR: akind = ATOMIC_TYPE_UCHAR; break;
-                       case ATOMIC_TYPE_SHORT: akind = ATOMIC_TYPE_USHORT; break;
-                       case ATOMIC_TYPE_INT: akind = ATOMIC_TYPE_UINT; break;
-                       case ATOMIC_TYPE_LONGLONG: akind = ATOMIC_TYPE_ULONGLONG; break;
-                       default:
-                               panic("invalid akind in mode attribute");
-                       }
-               } else {
-                       switch (akind) {
-                       case ATOMIC_TYPE_CHAR: akind = ATOMIC_TYPE_SCHAR; break;
-                       case ATOMIC_TYPE_SHORT: akind = ATOMIC_TYPE_SHORT; break;
-                       case ATOMIC_TYPE_INT: akind = ATOMIC_TYPE_INT; break;
-                       case ATOMIC_TYPE_LONGLONG: akind = ATOMIC_TYPE_LONGLONG; break;
-                       default:
-                               panic("invalid akind in mode attribute");
+               if (attribute->kind == GNU_AK_MODE) {
+                       type = handle_attribute_mode(attribute, type);
+               } else if (attribute->kind == GNU_AK_ALIGNED) {
+                       int alignment = 32; /* TODO: fill in maximum usefull alignment for target machine */
+                       if (attribute->has_arguments)
+                               alignment = attribute->u.argument;
+
+                       if (entity->kind == ENTITY_TYPEDEF) {
+                               type_t *copy         = duplicate_type(type);
+                               copy->base.alignment = attribute->u.argument;
+                               type                 = identify_new_type(copy);
+                       } else if(entity->kind == ENTITY_VARIABLE) {
+                               entity->variable.alignment = alignment;
+                       } else if(entity->kind == ENTITY_COMPOUND_MEMBER) {
+                               entity->compound_member.alignment = alignment;
                        }
                }
-
-               type = make_atomic_type(akind, type->base.qualifiers);
        }
 
        type_modifiers_t type_modifiers = type->base.modifiers;
@@ -4585,13 +4619,9 @@ static void parse_declaration_attributes(entity_t *entity)
                type_modifiers |= TYPE_MODIFIER_TRANSPARENT_UNION;
 
        if (type->base.modifiers != type_modifiers) {
-               type_t *copy = duplicate_type(type);
+               type_t *copy         = duplicate_type(type);
                copy->base.modifiers = type_modifiers;
-
-               type = typehash_insert(copy);
-               if (type != copy) {
-                       obstack_free(type_obst, copy);
-               }
+               type                 = identify_new_type(copy);
        }
 
        if (entity->kind == ENTITY_TYPEDEF) {
@@ -4619,7 +4649,7 @@ static type_t *construct_declarator_type(construct_type_t *construct_list, type_
                        function_type->function.return_type = type;
 
                        type_t *skipped_return_type = skip_typeref(type);
-                       /* §6.7.5.3(1) */
+                       /* §6.7.5.3:1 */
                        if (is_type_function(skipped_return_type)) {
                                errorf(HERE, "function returning function is not allowed");
                        } else if (is_type_array(skipped_return_type)) {
@@ -4681,7 +4711,7 @@ static type_t *construct_declarator_type(construct_type_t *construct_list, type_
                        }
 
                        type_t *skipped_type = skip_typeref(type);
-                       /* §6.7.5.2(1) */
+                       /* §6.7.5.2:1 */
                        if (is_type_incomplete(skipped_type)) {
                                errorf(HERE, "array of incomplete type '%T' is not allowed", type);
                        } else if (is_type_function(skipped_type)) {
@@ -4692,14 +4722,12 @@ static type_t *construct_declarator_type(construct_type_t *construct_list, type_
                }
                }
 
-               type_t *hashed_type = typehash_insert(type);
-               if (hashed_type != type) {
-                       /* the function type was constructed earlier freeing it here will
-                        * destroy other types... */
-                       if (iter->kind != CONSTRUCT_FUNCTION) {
-                               free_type(type);
-                       }
-                       type = hashed_type;
+               /* The function type was constructed earlier.  Freeing it here will
+                * destroy other types. */
+               if (iter->kind == CONSTRUCT_FUNCTION) {
+                       type = typehash_insert(type);
+               } else {
+                       type = identify_new_type(type);
                }
        }
 
@@ -4784,16 +4812,18 @@ static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
                if (flags & DECL_CREATE_COMPOUND_MEMBER) {
                        entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER);
 
-                       if (specifiers->is_inline && is_type_valid(type)) {
-                               errorf(&env.source_position,
-                                               "compound member '%Y' declared 'inline'", env.symbol);
-                       }
+                       if (env.symbol != NULL) {
+                               if (specifiers->is_inline && is_type_valid(type)) {
+                                       errorf(&env.source_position,
+                                                       "compound member '%Y' declared 'inline'", env.symbol);
+                               }
 
-                       if (specifiers->thread_local ||
-                               specifiers->storage_class != STORAGE_CLASS_NONE) {
-                               errorf(&env.source_position,
-                                          "compound member '%Y' must have no storage class",
-                                          env.symbol);
+                               if (specifiers->thread_local ||
+                                               specifiers->storage_class != STORAGE_CLASS_NONE) {
+                                       errorf(&env.source_position,
+                                                       "compound member '%Y' must have no storage class",
+                                                       env.symbol);
+                               }
                        }
                } else if (flags & DECL_IS_PARAMETER) {
                        orig_type = semantic_parameter(&env.source_position, orig_type,
@@ -4806,52 +4836,56 @@ static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
                        entity->function.is_inline  = specifiers->is_inline;
                        entity->function.parameters = env.parameters;
 
-                       if (specifiers->thread_local || (
-                                       specifiers->storage_class != STORAGE_CLASS_EXTERN &&
-                                       specifiers->storage_class != STORAGE_CLASS_NONE   &&
-                                       specifiers->storage_class != STORAGE_CLASS_STATIC)
-                          ) {
-                               errorf(&env.source_position,
-                                          "invalid storage class for function '%Y'", env.symbol);
+                       if (env.symbol != NULL) {
+                               if (specifiers->thread_local || (
+                                                       specifiers->storage_class != STORAGE_CLASS_EXTERN &&
+                                                       specifiers->storage_class != STORAGE_CLASS_NONE   &&
+                                                       specifiers->storage_class != STORAGE_CLASS_STATIC
+                                               )) {
+                                       errorf(&env.source_position,
+                                                       "invalid storage class for function '%Y'", env.symbol);
+                               }
                        }
                } else {
                        entity = allocate_entity_zero(ENTITY_VARIABLE);
 
                        entity->variable.get_property_sym = specifiers->get_property_sym;
                        entity->variable.put_property_sym = specifiers->put_property_sym;
-                       if (specifiers->alignment != 0) {
-                               /* TODO: add checks here */
-                               entity->variable.alignment = specifiers->alignment;
-                       }
-
-                       if (specifiers->is_inline && is_type_valid(type)) {
-                               errorf(&env.source_position,
-                                          "variable '%Y' declared 'inline'", env.symbol);
-                       }
 
                        entity->variable.thread_local = specifiers->thread_local;
 
-                       bool invalid_storage_class = false;
-                       if (current_scope == file_scope) {
-                               if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
-                                               specifiers->storage_class != STORAGE_CLASS_NONE   &&
-                                               specifiers->storage_class != STORAGE_CLASS_STATIC) {
-                                       invalid_storage_class = true;
+                       if (env.symbol != NULL) {
+                               if (specifiers->is_inline && is_type_valid(type)) {
+                                       errorf(&env.source_position,
+                                                       "variable '%Y' declared 'inline'", env.symbol);
                                }
-                       } else {
-                               if (specifiers->thread_local &&
-                                               specifiers->storage_class == STORAGE_CLASS_NONE) {
-                                       invalid_storage_class = true;
+
+                               bool invalid_storage_class = false;
+                               if (current_scope == file_scope) {
+                                       if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
+                                                       specifiers->storage_class != STORAGE_CLASS_NONE   &&
+                                                       specifiers->storage_class != STORAGE_CLASS_STATIC) {
+                                               invalid_storage_class = true;
+                                       }
+                               } else {
+                                       if (specifiers->thread_local &&
+                                                       specifiers->storage_class == STORAGE_CLASS_NONE) {
+                                               invalid_storage_class = true;
+                                       }
+                               }
+                               if (invalid_storage_class) {
+                                       errorf(&env.source_position,
+                                                       "invalid storage class for variable '%Y'", env.symbol);
                                }
-                       }
-                       if (invalid_storage_class) {
-                               errorf(&env.source_position,
-                                               "invalid storage class for variable '%Y'", env.symbol);
                        }
                }
 
-               entity->base.source_position          = env.source_position;
-               entity->base.symbol                   = env.symbol;
+               if (env.symbol != NULL) {
+                       entity->base.symbol          = env.symbol;
+                       entity->base.source_position = env.source_position;
+               } else {
+                       entity->base.source_position = specifiers->source_position;
+               }
                entity->base.namespc                  = NAMESPACE_NORMAL;
                entity->declaration.type              = orig_type;
                entity->declaration.modifiers         = env.modifiers;
@@ -5256,7 +5290,7 @@ static void parse_init_declarator_rest(entity_t *entity)
        current_init_decl = NULL;
 
        if (entity->kind == ENTITY_VARIABLE) {
-               /* § 6.7.5 (22)  array initializers for arrays with unknown size
+               /* § 6.7.5:22  array initializers for arrays with unknown size
                 * determine the array type size */
                declaration->type            = env.type;
                entity->variable.initializer = initializer;
@@ -5523,12 +5557,9 @@ decl_list_end:
        new_type->function.parameters             = parameters;
        new_type->function.unspecified_parameters = true;
 
-       type = typehash_insert(new_type);
-       if (type != new_type) {
-               obstack_free(type_obst, new_type);
-       }
+       new_type = identify_new_type(new_type);
 
-       entity->declaration.type = type;
+       entity->declaration.type = new_type;
 
        rem_anchor_token('{');
 }
@@ -5799,7 +5830,6 @@ static void check_reachable(statement_t *const stmt)
        switch (stmt->kind) {
                case STATEMENT_INVALID:
                case STATEMENT_EMPTY:
-               case STATEMENT_LOCAL_LABEL:
                case STATEMENT_ASM:
                        next = stmt->base.next;
                        break;
@@ -5825,6 +5855,8 @@ static void check_reachable(statement_t *const stmt)
 
                case STATEMENT_COMPOUND:
                        next = stmt->compound.statements;
+                       if (next == NULL)
+                               next = stmt->base.next;
                        break;
 
                case STATEMENT_RETURN: {
@@ -6076,7 +6108,6 @@ found_break_parent:
                        case STATEMENT_INVALID:
                        case STATEMENT_EMPTY:
                        case STATEMENT_DECLARATION:
-                       case STATEMENT_LOCAL_LABEL:
                        case STATEMENT_EXPRESSION:
                        case STATEMENT_ASM:
                        case STATEMENT_RETURN:
@@ -6338,18 +6369,15 @@ static void parse_external_declaration(void)
                        ndeclaration->base.symbol);
        }
 
-       /* § 6.7.5.3 (14) a function definition with () means no
+       /* § 6.7.5.3:14 a function definition with () means no
         * parameters (and not unspecified parameters) */
-       if (type->function.unspecified_parameters
-                       && type->function.parameters == NULL
-                       && !type->function.kr_style_parameters) {
-               type_t *duplicate = duplicate_type(type);
-               duplicate->function.unspecified_parameters = false;
+       if (type->function.unspecified_parameters &&
+                       type->function.parameters == NULL     &&
+                       !type->function.kr_style_parameters) {
+               type_t *copy                          = duplicate_type(type);
+               copy->function.unspecified_parameters = false;
+               type                                  = identify_new_type(copy);
 
-               type = typehash_insert(duplicate);
-               if (type != duplicate) {
-                       obstack_free(type_obst, duplicate);
-               }
                ndeclaration->declaration.type = type;
        }
 
@@ -6514,53 +6542,58 @@ static void parse_compound_declarators(compound_t *compound,
                        entity->declaration.storage_class          = STORAGE_CLASS_NONE;
                        entity->declaration.modifiers              = specifiers->modifiers;
                        entity->declaration.type                   = type;
+                       append_entity(&compound->members, entity);
                } else {
                        entity = parse_declarator(specifiers,
                                        DECL_MAY_BE_ABSTRACT | DECL_CREATE_COMPOUND_MEMBER);
-                       assert(entity->kind == ENTITY_COMPOUND_MEMBER);
-
-                       if (token.type == ':') {
-                               source_position_t source_position = *HERE;
-                               next_token();
-                               expression_t *size = parse_constant_expression();
-
-                               type_t *type = entity->declaration.type;
-                               type_t *bitfield_type = make_bitfield_type(type, size,
-                                               &source_position, entity->base.symbol);
-                               entity->declaration.type = bitfield_type;
-                       }
-               }
-
-               /* make sure we don't define a symbol multiple times */
-               symbol_t *symbol = entity->base.symbol;
-               if (symbol != NULL) {
-                       entity_t *prev = find_compound_entry(compound, symbol);
-
-                       if (prev != NULL) {
+                       if (entity->kind == ENTITY_TYPEDEF) {
                                errorf(&entity->base.source_position,
-                                      "multiple declarations of symbol '%Y' (declared %P)",
-                                      symbol, &prev->base.source_position);
-                       }
-               }
+                                               "typedef not allowed as compound member");
+                       } else {
+                               assert(entity->kind == ENTITY_COMPOUND_MEMBER);
+
+                               /* make sure we don't define a symbol multiple times */
+                               symbol_t *symbol = entity->base.symbol;
+                               if (symbol != NULL) {
+                                       entity_t *prev = find_compound_entry(compound, symbol);
+                                       if (prev != NULL) {
+                                               errorf(&entity->base.source_position,
+                                                               "multiple declarations of symbol '%Y' (declared %P)",
+                                                               symbol, &prev->base.source_position);
+                                       }
+                               }
 
-               append_entity(&compound->members, entity);
+                               if (token.type == ':') {
+                                       source_position_t source_position = *HERE;
+                                       next_token();
+                                       expression_t *size = parse_constant_expression();
 
-               type_t *orig_type = entity->declaration.type;
-               type_t *type      = skip_typeref(orig_type);
-               if (is_type_function(type)) {
-                       errorf(&entity->base.source_position,
-                                       "compound member '%Y' must not have function type '%T'",
-                                       entity->base.symbol, orig_type);
-               } else if (is_type_incomplete(type)) {
-                       /* §6.7.2.1:16 flexible array member */
-                       if (is_type_array(type) &&
-                                       token.type == ';'   &&
-                                       look_ahead(1)->type == '}') {
-                               compound->has_flexible_member = true;
-                       } else {
-                               errorf(&entity->base.source_position,
-                                               "compound member '%Y' has incomplete type '%T'",
-                                               entity->base.symbol, orig_type);
+                                       type_t *type          = entity->declaration.type;
+                                       type_t *bitfield_type = make_bitfield_type(type, size,
+                                                       &source_position, entity->base.symbol);
+                                       entity->declaration.type = bitfield_type;
+                               } else {
+                                       type_t *orig_type = entity->declaration.type;
+                                       type_t *type      = skip_typeref(orig_type);
+                                       if (is_type_function(type)) {
+                                               errorf(&entity->base.source_position,
+                                                               "compound member '%Y' must not have function type '%T'",
+                                                               entity->base.symbol, orig_type);
+                                       } else if (is_type_incomplete(type)) {
+                                               /* §6.7.2.1:16 flexible array member */
+                                               if (is_type_array(type) &&
+                                                               token.type == ';'   &&
+                                                               look_ahead(1)->type == '}') {
+                                                       compound->has_flexible_member = true;
+                                               } else {
+                                                       errorf(&entity->base.source_position,
+                                                                       "compound member '%Y' has incomplete type '%T'",
+                                                                       entity->base.symbol, orig_type);
+                                               }
+                                       }
+                               }
+
+                               append_entity(&compound->members, entity);
                        }
                }
 
@@ -6624,7 +6657,7 @@ typedef expression_t* (*parse_expression_infix_function)(expression_t *left);
 typedef struct expression_parser_function_t expression_parser_function_t;
 struct expression_parser_function_t {
        parse_expression_function        parser;
-       unsigned                         infix_precedence;
+       precedence_t                     infix_precedence;
        parse_expression_infix_function  infix_parser;
 };
 
@@ -6785,11 +6818,7 @@ static entity_t *create_implicit_function(symbol_t *symbol,
        ntype->function.return_type            = type_int;
        ntype->function.unspecified_parameters = true;
        ntype->function.linkage                = LINKAGE_C;
-
-       type_t *type = typehash_insert(ntype);
-       if (type != ntype) {
-               free_type(ntype);
-       }
+       type_t *type                           = identify_new_type(ntype);
 
        entity_t *entity = allocate_entity_zero(ENTITY_FUNCTION);
        entity->declaration.storage_class          = STORAGE_CLASS_EXTERN;
@@ -6829,12 +6858,7 @@ static type_t *make_function_2_type(type_t *return_type, type_t *argument_type1,
        type->function.return_type = return_type;
        type->function.parameters  = parameter1;
 
-       type_t *result = typehash_insert(type);
-       if (result != type) {
-               free_type(type);
-       }
-
-       return result;
+       return identify_new_type(type);
 }
 
 /**
@@ -6855,12 +6879,7 @@ static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
        type->function.return_type = return_type;
        type->function.parameters  = parameter;
 
-       type_t *result = typehash_insert(type);
-       if (result != type) {
-               free_type(type);
-       }
-
-       return result;
+       return identify_new_type(type);
 }
 
 static type_t *make_function_0_type(type_t *return_type)
@@ -6869,12 +6888,7 @@ static type_t *make_function_0_type(type_t *return_type)
        type->function.return_type = return_type;
        type->function.parameters  = NULL;
 
-       type_t *result = typehash_insert(type);
-       if (result != type) {
-               free_type(type);
-       }
-
-       return result;
+       return identify_new_type(type);
 }
 
 /**
@@ -6956,13 +6970,14 @@ type_t *revert_automatic_type_conversion(const expression_t *expression)
                        assert(is_declaration(entity));
                        type_t   *type   = entity->declaration.type;
                        return get_qualified_type(type,
-                                                 expression->base.type->base.qualifiers);
+                                       expression->base.type->base.qualifiers);
                }
 
                case EXPR_UNARY_DEREFERENCE: {
                        const expression_t *const value = expression->unary.value;
                        type_t             *const type  = skip_typeref(value->base.type);
-                       assert(is_type_pointer(type));
+                       if (!is_type_pointer(type))
+                               return type_error_type;
                        return type->pointer.points_to;
                }
 
@@ -6972,9 +6987,8 @@ type_t *revert_automatic_type_conversion(const expression_t *expression)
                case EXPR_ARRAY_ACCESS: {
                        const expression_t *array_ref = expression->array_access.array_ref;
                        type_t             *type_left = skip_typeref(array_ref->base.type);
-                       if (!is_type_valid(type_left))
-                               return type_left;
-                       assert(is_type_pointer(type_left));
+                       if (!is_type_pointer(type_left))
+                               return type_error_type;
                        return type_left->pointer.points_to;
                }
 
@@ -6991,10 +7005,9 @@ type_t *revert_automatic_type_conversion(const expression_t *expression)
                case EXPR_COMPOUND_LITERAL:
                        return expression->compound_literal.type;
 
-               default: break;
+               default:
+                       return expression->base.type;
        }
-
-       return expression->base.type;
 }
 
 static expression_t *parse_reference(void)
@@ -8523,7 +8536,7 @@ static bool check_pointer_arithmetic(const source_position_t *source_position,
 
 static bool is_lvalue(const expression_t *expression)
 {
-       /* TODO: doesn't seem to be consistent with §6.3.2.1 (1) */
+       /* TODO: doesn't seem to be consistent with §6.3.2.1:1 */
        switch (expression->kind) {
        case EXPR_ARRAY_ACCESS:
        case EXPR_COMPOUND_LITERAL:
@@ -9008,6 +9021,13 @@ static void warn_comparison_in_comparison(const expression_t *const expr)
        }
 }
 
+static bool maybe_negative(expression_t const *const expr)
+{
+       return
+               !is_constant_expression(expr) ||
+               fold_constant(expr) < 0;
+}
+
 /**
  * Check the semantics of comparison expressions.
  *
@@ -9049,37 +9069,23 @@ static void semantic_comparison(binary_expression_t *expression)
 
        /* TODO non-arithmetic types */
        if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
-               /* test for signed vs unsigned compares */
-               if (warning.sign_compare &&
-                   (expression->base.kind != EXPR_BINARY_EQUAL &&
-                    expression->base.kind != EXPR_BINARY_NOTEQUAL) &&
-                   (is_type_signed(type_left) != is_type_signed(type_right))) {
-
-                       /* check if 1 of the operands is a constant, in this case we just
-                        * check wether we can safely represent the resulting constant in
-                        * the type of the other operand. */
-                       expression_t *const_expr = NULL;
-                       expression_t *other_expr = NULL;
-
-                       if (is_constant_expression(left)) {
-                               const_expr = left;
-                               other_expr = right;
-                       } else if (is_constant_expression(right)) {
-                               const_expr = right;
-                               other_expr = left;
-                       }
+               type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
 
-                       if (const_expr != NULL) {
-                               type_t *other_type = skip_typeref(other_expr->base.type);
-                               long    val        = fold_constant(const_expr);
-                               /* TODO: check if val can be represented by other_type */
-                               (void) other_type;
-                               (void) val;
+               /* test for signed vs unsigned compares */
+               if (warning.sign_compare && is_type_integer(arithmetic_type)) {
+                       bool const signed_left  = is_type_signed(type_left);
+                       bool const signed_right = is_type_signed(type_right);
+                       if (signed_left != signed_right) {
+                               /* FIXME long long needs better const folding magic */
+                               /* TODO check whether constant value can be represented by other type */
+                               if ((signed_left  && maybe_negative(left)) ||
+                                               (signed_right && maybe_negative(right))) {
+                                       warningf(&expression->base.source_position,
+                                                       "comparison between signed and unsigned");
+                               }
                        }
-                       warningf(&expression->base.source_position,
-                                "comparison between signed and unsigned");
                }
-               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->base.type   = arithmetic_type;
@@ -9549,7 +9555,7 @@ static void register_expression_parser(parse_expression_function parser,
  * @param precedence  the precedence of the operator
  */
 static void register_infix_parser(parse_expression_infix_function parser,
-               int token_type, unsigned precedence)
+               int token_type, precedence_t precedence)
 {
        expression_parser_function_t *entry = &expression_parsers[token_type];
 
@@ -11366,9 +11372,7 @@ static void complete_incomplete_arrays(void)
                new_type->array.has_implicit_size = true;
                new_type->array.size              = 1;
 
-               type_t *const result = typehash_insert(new_type);
-               if (type != result)
-                       free_type(type);
+               type_t *const result = identify_new_type(new_type);
 
                decl->type = result;
        }