Slightly simplify daisy chaining gotos.
[cparser] / parser.c
index 92cd0e4..417b1e2 100644 (file)
--- a/parser.c
+++ b/parser.c
 #include "adt/error.h"
 #include "adt/array.h"
 
-/** if wchar_t is equal to unsigned short. */
-bool opt_short_wchar_t =
-#ifdef _WIN32
-       true;
-#else
-       false;
-#endif
-
 //#define PRINT_TOKENS
 #define MAX_LOOKAHEAD 2
 
 typedef struct {
-       entity_t    *old_entity;
-       symbol_t    *symbol;
-       namespace_t  namespc;
+       entity_t           *old_entity;
+       symbol_t           *symbol;
+       entity_namespace_t  namespc;
 } stack_entry_t;
 
 typedef struct argument_list_t argument_list_t;
@@ -108,35 +100,34 @@ typedef struct parse_initializer_env_t {
 typedef entity_t* (*parsed_declaration_func) (entity_t *declaration, bool is_definition);
 
 /** The current token. */
-static token_t             token;
+static token_t              token;
 /** The lookahead ring-buffer. */
-static token_t             lookahead_buffer[MAX_LOOKAHEAD];
+static token_t              lookahead_buffer[MAX_LOOKAHEAD];
 /** Position of the next token in the lookahead buffer. */
-static int                 lookahead_bufpos;
-static stack_entry_t      *environment_stack = NULL;
-static stack_entry_t      *label_stack       = NULL;
-/** The global file scope. */
-static scope_t            *file_scope        = NULL;
-/** The current scope. */
-static scope_t            *scope             = NULL;
+static int                  lookahead_bufpos;
+static stack_entry_t       *environment_stack = NULL;
+static stack_entry_t       *label_stack       = NULL;
+static scope_t             *file_scope        = NULL;
+static scope_t             *current_scope     = NULL;
 /** Point to the current function declaration if inside a function. */
-static function_t         *current_function  = NULL;
-static entity_t           *current_init_decl = NULL;
-static switch_statement_t *current_switch    = NULL;
-static statement_t        *current_loop      = NULL;
-static statement_t        *current_parent    = NULL;
-static ms_try_statement_t *current_try       = NULL;
-static goto_statement_t   *goto_first        = NULL;
-static goto_statement_t   *goto_last         = NULL;
-static label_statement_t  *label_first       = NULL;
-static label_statement_t  *label_last        = NULL;
+static function_t          *current_function  = NULL;
+static entity_t            *current_init_decl = NULL;
+static switch_statement_t  *current_switch    = NULL;
+static statement_t         *current_loop      = NULL;
+static statement_t         *current_parent    = NULL;
+static ms_try_statement_t  *current_try       = NULL;
+static linkage_kind_t       current_linkage   = LINKAGE_INVALID;
+static goto_statement_t    *goto_first        = NULL;
+static goto_statement_t   **goto_anchor       = NULL;
+static label_statement_t   *label_first       = NULL;
+static label_statement_t  **label_anchor      = NULL;
 /** current translation unit. */
-static translation_unit_t *unit              = NULL;
+static translation_unit_t  *unit              = NULL;
 /** true if we are in a type property context (evaluation only for type. */
-static bool                in_type_prop      = false;
+static bool                 in_type_prop      = false;
 /** true in we are in a __extension__ context. */
-static bool                in_gcc_extension  = false;
-static struct obstack      temp_obst;
+static bool                 in_gcc_extension  = false;
+static struct obstack       temp_obst;
 
 
 #define PUSH_PARENT(stmt)                          \
@@ -184,6 +175,8 @@ static statement_t *parse_statement(void);
 static expression_t *parse_sub_expression(precedence_t);
 static expression_t *parse_expression(void);
 static type_t       *parse_typename(void);
+static void          parse_externals(void);
+static void          parse_external(void);
 
 static void parse_compound_type_entries(compound_t *compound_declaration);
 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
@@ -201,6 +194,13 @@ static void semantic_comparison(binary_expression_t *expression);
        case T_register:        \
        case T___thread:
 
+#define STORAGE_CLASSES_NO_EXTERN \
+       case T_typedef:         \
+       case T_static:          \
+       case T_auto:            \
+       case T_register:        \
+       case T___thread:
+
 #define TYPE_QUALIFIERS     \
        case T_const:           \
        case T_restrict:        \
@@ -209,15 +209,10 @@ static void semantic_comparison(binary_expression_t *expression);
        case T__forceinline:    \
        case T___attribute__:
 
-#ifdef PROVIDE_COMPLEX
 #define COMPLEX_SPECIFIERS  \
        case T__Complex:
 #define IMAGINARY_SPECIFIERS \
        case T__Imaginary:
-#else
-#define COMPLEX_SPECIFIERS
-#define IMAGINARY_SPECIFIERS
-#endif
 
 #define TYPE_SPECIFIERS       \
        case T__Bool:             \
@@ -245,6 +240,11 @@ static void semantic_comparison(binary_expression_t *expression);
        TYPE_QUALIFIERS         \
        TYPE_SPECIFIERS
 
+#define DECLARATION_START_NO_EXTERN \
+       STORAGE_CLASSES_NO_EXTERN       \
+       TYPE_QUALIFIERS                 \
+       TYPE_SPECIFIERS
+
 #define TYPENAME_START      \
        TYPE_QUALIFIERS         \
        TYPE_SPECIFIERS
@@ -325,7 +325,8 @@ static size_t get_entity_struct_size(entity_kind_t kind)
                [ENTITY_ENUM]            = sizeof(enum_t),
                [ENTITY_ENUM_VALUE]      = sizeof(enum_value_t),
                [ENTITY_LABEL]           = sizeof(label_t),
-               [ENTITY_LOCAL_LABEL]     = sizeof(label_t)
+               [ENTITY_LOCAL_LABEL]     = sizeof(label_t),
+               [ENTITY_NAMESPACE]       = sizeof(namespace_t)
        };
        assert(kind < sizeof(sizes) / sizeof(sizes[0]));
        assert(sizes[kind] != 0);
@@ -774,22 +775,23 @@ static void type_error_incompatible(const char *msg,
 
 static void scope_push(scope_t *new_scope)
 {
-       if (scope != NULL) {
-               new_scope->depth = scope->depth + 1;
+       if (current_scope != NULL) {
+               new_scope->depth = current_scope->depth + 1;
        }
-       new_scope->parent = scope;
-       scope             = new_scope;
+       new_scope->parent = current_scope;
+       current_scope     = new_scope;
 }
 
 static void scope_pop(void)
 {
-       scope = scope->parent;
+       current_scope = current_scope->parent;
 }
 
 /**
  * Search an entity by its symbol in a given namespace.
  */
-static entity_t *get_entity(const symbol_t *const symbol, namespace_t namespc)
+static entity_t *get_entity(const symbol_t *const symbol,
+                            namespace_tag_t namespc)
 {
        entity_t *entity = symbol->entity;
        for( ; entity != NULL; entity = entity->base.symbol_next) {
@@ -806,8 +808,8 @@ static entity_t *get_entity(const symbol_t *const symbol, namespace_t namespc)
  */
 static void stack_push(stack_entry_t **stack_ptr, entity_t *entity)
 {
-       symbol_t    *symbol  = entity->base.symbol;
-       namespace_t  namespc = entity->base.namespc;
+       symbol_t           *symbol  = entity->base.symbol;
+       entity_namespace_t  namespc = entity->base.namespc;
        assert(namespc != NAMESPACE_INVALID);
 
        /* replace/add entity into entity list of the symbol */
@@ -872,9 +874,9 @@ static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
        for(i = top; i > new_top; --i) {
                stack_entry_t *entry = &stack[i - 1];
 
-               entity_t    *old_entity = entry->old_entity;
-               symbol_t    *symbol     = entry->symbol;
-               namespace_t  namespc    = entry->namespc;
+               entity_t           *old_entity = entry->old_entity;
+               symbol_t           *symbol     = entry->symbol;
+               entity_namespace_t  namespc    = entry->namespc;
 
                /* replace with old_entity/remove */
                entity_t **anchor;
@@ -2954,13 +2956,13 @@ static compound_t *parse_compound_type_specifier(bool is_struct)
                symbol = token.v.symbol;
                next_token();
 
-               namespace_t const namespc =
+               namespace_tag_t const namespc =
                        is_struct ? NAMESPACE_STRUCT : NAMESPACE_UNION;
                entity_t *entity = get_entity(symbol, namespc);
                if (entity != NULL) {
                        assert(entity->kind == (is_struct ? ENTITY_STRUCT : ENTITY_UNION));
                        compound = &entity->compound;
-                       if (compound->base.parent_scope != scope &&
+                       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 */
@@ -2995,11 +2997,11 @@ static compound_t *parse_compound_type_specifier(bool is_struct)
                        (is_struct ? NAMESPACE_STRUCT : NAMESPACE_UNION);
                compound->base.source_position = token.source_position;
                compound->base.symbol          = symbol;
-               compound->base.parent_scope    = scope;
+               compound->base.parent_scope    = current_scope;
                if (symbol != NULL) {
                        environment_push(entity);
                }
-               append_entity(scope, entity);
+               append_entity(current_scope, entity);
        }
 
        if (token.type == '{') {
@@ -3089,7 +3091,7 @@ static type_t *parse_enum_specifier(void)
                entity->base.namespc         = NAMESPACE_ENUM;
                entity->base.source_position = token.source_position;
                entity->base.symbol          = symbol;
-               entity->base.parent_scope    = scope;
+               entity->base.parent_scope    = current_scope;
        }
 
        type_t *const type = allocate_type_zero(TYPE_ENUM);
@@ -3103,7 +3105,7 @@ static type_t *parse_enum_specifier(void)
                if (symbol != NULL) {
                        environment_push(entity);
                }
-               append_entity(scope, entity);
+               append_entity(current_scope, entity);
                entity->enume.complete = true;
 
                parse_enum_entries(type);
@@ -3590,12 +3592,12 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                /* type specifiers */
 #define MATCH_SPECIFIER(token, specifier, name)                         \
                case token:                                                     \
-                       next_token();                                               \
                        if (type_specifiers & specifier) {                           \
                                errorf(HERE, "multiple " name " type specifiers given"); \
                        } else {                                                    \
                                type_specifiers |= specifier;                           \
                        }                                                           \
+                       next_token();                                               \
                        break
 
                MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool");
@@ -3627,7 +3629,6 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                        break;
 
                case T_long:
-                       next_token();
                        if (type_specifiers & SPECIFIER_LONG_LONG) {
                                errorf(HERE, "multiple type specifiers given");
                        } else if (type_specifiers & SPECIFIER_LONG) {
@@ -3635,6 +3636,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                        } else {
                                type_specifiers |= SPECIFIER_LONG;
                        }
+                       next_token();
                        break;
 
                case T_struct: {
@@ -4203,6 +4205,8 @@ static construct_type_t *parse_function_declarator(scope_t *scope)
 {
        type_t *type = allocate_type_zero(TYPE_FUNCTION);
 
+       type->function.linkage = current_linkage;
+
        /* TODO: revive this... once we know exactly how to do it */
 #if 0
        decl_modifiers_t  modifiers = entity->declaration.modifiers;
@@ -4589,7 +4593,8 @@ static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
                storage_class_t storage_class = specifiers->storage_class;
                entity->declaration.declared_storage_class = storage_class;
 
-               if (storage_class == STORAGE_CLASS_NONE && scope != file_scope) {
+               if (storage_class == STORAGE_CLASS_NONE
+                               && current_scope != file_scope) {
                        storage_class = STORAGE_CLASS_AUTO;
                }
                entity->declaration.storage_class = storage_class;
@@ -4681,6 +4686,34 @@ static bool is_sym_main(const symbol_t *const sym)
        return strcmp(sym->string, "main") == 0;
 }
 
+static const char *get_entity_kind_name(entity_kind_t kind)
+{
+       switch ((entity_kind_tag_t) kind) {
+       case ENTITY_FUNCTION:        return "function";
+       case ENTITY_VARIABLE:        return "variable";
+       case ENTITY_COMPOUND_MEMBER: return "compound type member";
+       case ENTITY_STRUCT:          return "struct";
+       case ENTITY_UNION:           return "union";
+       case ENTITY_ENUM:            return "enum";
+       case ENTITY_ENUM_VALUE:      return "enum value";
+       case ENTITY_LABEL:           return "label";
+       case ENTITY_LOCAL_LABEL:     return "local label";
+       case ENTITY_TYPEDEF:         return "typedef";
+       case ENTITY_NAMESPACE:       return "namespace";
+       case ENTITY_INVALID:         break;
+       }
+
+       panic("Invalid entity kind encountered in get_entity_kind_name");
+}
+
+static void error_redefined_as_different_kind(const source_position_t *pos,
+               const entity_t *old, entity_kind_t new_kind)
+{
+       errorf(pos, "redeclaration of %s '%Y' as %s (declared %P)",
+              get_entity_kind_name(old->kind), old->base.symbol,
+              get_entity_kind_name(new_kind), &old->base.source_position);
+}
+
 /**
  * record entities for the NAMESPACE_NORMAL, and produce error messages/warnings
  * for various problems that occur for multiple definitions
@@ -4688,7 +4721,7 @@ static bool is_sym_main(const symbol_t *const sym)
 static entity_t *record_entity(entity_t *entity, const bool is_definition)
 {
        const symbol_t *const    symbol  = entity->base.symbol;
-       const namespace_t        namespc = entity->base.namespc;
+       const namespace_tag_t    namespc = (namespace_tag_t)entity->base.namespc;
        const source_position_t *pos     = &entity->base.source_position;
 
        assert(symbol != NULL);
@@ -4708,7 +4741,8 @@ static entity_t *record_entity(entity_t *entity, const bool is_definition)
                                         orig_type, symbol);
                }
 
-               if (warning.main && scope == file_scope && is_sym_main(symbol)) {
+               if (warning.main && current_scope == file_scope
+                               && is_sym_main(symbol)) {
                        check_type_of_main(entity);
                }
        }
@@ -4716,7 +4750,7 @@ static entity_t *record_entity(entity_t *entity, const bool is_definition)
        if (is_declaration(entity)) {
                if (warning.nested_externs
                                && entity->declaration.storage_class == STORAGE_CLASS_EXTERN
-                               && scope != file_scope) {
+                               && current_scope != file_scope) {
                        warningf(pos, "nested extern declaration of '%#T'",
                                 entity->declaration.type, symbol);
                }
@@ -4724,7 +4758,7 @@ static entity_t *record_entity(entity_t *entity, const bool is_definition)
 
        if (previous_entity != NULL
            && previous_entity->base.parent_scope == &current_function->parameters
-               && scope->depth == previous_entity->base.parent_scope->depth + 1) {
+               && current_scope->depth == previous_entity->base.parent_scope->depth+1){
 
                assert(previous_entity->kind == ENTITY_VARIABLE);
                errorf(pos,
@@ -4736,12 +4770,11 @@ static entity_t *record_entity(entity_t *entity, const bool is_definition)
        }
 
        if (previous_entity != NULL
-                       && previous_entity->base.parent_scope == scope) {
+                       && previous_entity->base.parent_scope == current_scope) {
 
                if (previous_entity->kind != entity->kind) {
-                       errorf(pos,
-                              "redeclaration of '%Y' as different kind of symbol (declared %P)",
-                              symbol, &previous_entity->base.source_position);
+                       error_redefined_as_different_kind(pos, previous_entity,
+                                                         entity->kind);
                        goto finish;
                }
                if (previous_entity->kind == ENTITY_ENUM_VALUE) {
@@ -4898,7 +4931,7 @@ error_redeclaration:
                }
        } else if (warning.missing_declarations
                        && entity->kind == ENTITY_VARIABLE
-                       && scope == file_scope) {
+                       && current_scope == file_scope) {
                declaration_t *declaration = &entity->declaration;
                if (declaration->storage_class == STORAGE_CLASS_NONE ||
                                declaration->storage_class == STORAGE_CLASS_THREAD) {
@@ -4909,12 +4942,12 @@ error_redeclaration:
 
 finish:
        assert(entity->base.parent_scope == NULL);
-       assert(scope != NULL);
+       assert(current_scope != NULL);
 
-       entity->base.parent_scope = scope;
+       entity->base.parent_scope = current_scope;
        entity->base.namespc      = NAMESPACE_NORMAL;
        environment_push(entity);
-       append_entity(scope, entity);
+       append_entity(current_scope, entity);
 
        return entity;
 }
@@ -5063,7 +5096,7 @@ static entity_t *finished_kr_declaration(entity_t *entity, bool is_definition)
        assert(entity->base.namespc == NAMESPACE_NORMAL);
        entity_t *previous_entity = get_entity(symbol, NAMESPACE_NORMAL);
        if (previous_entity == NULL
-                       || previous_entity->base.parent_scope != scope) {
+                       || previous_entity->base.parent_scope != current_scope) {
                errorf(HERE, "expected declaration of a function parameter, found '%Y'",
                       symbol);
                return entity;
@@ -5127,7 +5160,7 @@ static void parse_kr_declaration_list(entity_t *entity)
        entity_t *parameter = entity->function.parameters.entities;
        for ( ; parameter != NULL; parameter = parameter->base.next) {
                assert(parameter->base.parent_scope == NULL);
-               parameter->base.parent_scope = scope;
+               parameter->base.parent_scope = current_scope;
                environment_push(parameter);
        }
 
@@ -5137,7 +5170,7 @@ static void parse_kr_declaration_list(entity_t *entity)
        }
 
        /* pop function parameters */
-       assert(scope == &entity->function.parameters);
+       assert(current_scope == &entity->function.parameters);
        scope_pop();
        environment_pop_to(top);
 
@@ -5239,8 +5272,8 @@ static void check_labels(void)
                               "label '%Y' used but not defined", label->base.symbol);
                 }
        }
-       goto_first = NULL;
-       goto_last  = NULL;
+       goto_first  = NULL;
+       goto_anchor = &goto_first;
 
        if (warning.unused_label) {
                for (const label_statement_t *label_statement = label_first;
@@ -5255,7 +5288,8 @@ static void check_labels(void)
                        }
                }
        }
-       label_first = label_last = NULL;
+       label_first  = NULL;
+       label_anchor = &label_first;
 }
 
 static void warn_unused_decl(entity_t *entity, entity_t *end,
@@ -5856,11 +5890,9 @@ static void parse_external_declaration(void)
        }
 
        assert(is_declaration(ndeclaration));
-       type_t *type = ndeclaration->declaration.type;
+       type_t *type = skip_typeref(ndeclaration->declaration.type);
 
-       /* note that we don't skip typerefs: the standard doesn't allow them here
-        * (so we can't use is_type_function here) */
-       if (type->kind != TYPE_FUNCTION) {
+       if (!is_type_function(type)) {
                if (is_type_valid(type)) {
                        errorf(HERE, "declarator '%#T' has a body but is not a function type",
                               type, ndeclaration->base.symbol);
@@ -5916,11 +5948,11 @@ static void parse_external_declaration(void)
        entity_t *parameter = function->parameters.entities;
        for( ; parameter != NULL; parameter = parameter->base.next) {
                if (parameter->base.parent_scope == &ndeclaration->function.parameters) {
-                       parameter->base.parent_scope = scope;
+                       parameter->base.parent_scope = current_scope;
                }
                assert(parameter->base.parent_scope == NULL
-                               || parameter->base.parent_scope == scope);
-               parameter->base.parent_scope = scope;
+                               || parameter->base.parent_scope == current_scope);
+               parameter->base.parent_scope = current_scope;
                if (parameter->base.symbol == NULL) {
                        errorf(&parameter->base.source_position, "parameter name omitted");
                        continue;
@@ -5966,7 +5998,7 @@ static void parse_external_declaration(void)
                label_pop_to(label_stack_top);
        }
 
-       assert(scope == &function->parameters);
+       assert(current_scope == &function->parameters);
        scope_pop();
        environment_pop_to(top);
 }
@@ -7195,8 +7227,8 @@ static label_t *get_label(symbol_t *symbol)
        label = get_entity(symbol, NAMESPACE_LABEL);
        /* if we found a local label, we already created the declaration */
        if (label != NULL && label->kind == ENTITY_LOCAL_LABEL) {
-               if (label->base.parent_scope != scope) {
-                       assert(label->base.parent_scope->depth < scope->depth);
+               if (label->base.parent_scope != current_scope) {
+                       assert(label->base.parent_scope->depth < current_scope->depth);
                        current_function->goto_to_outer = true;
                }
                return &label->label;
@@ -7715,6 +7747,48 @@ static bool same_compound_type(const type_t *type1, const type_t *type2)
                type1->compound.compound == type2->compound.compound;
 }
 
+static expression_t const *get_reference_address(expression_t const *expr)
+{
+       bool regular_take_address = true;
+       for (;;) {
+               if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
+                       expr = expr->unary.value;
+               } else {
+                       regular_take_address = false;
+               }
+
+               if (expr->kind != EXPR_UNARY_DEREFERENCE)
+                       break;
+
+               expr = expr->unary.value;
+       }
+
+       if (expr->kind != EXPR_REFERENCE)
+               return NULL;
+
+       /* special case for functions which are automatically converted to a
+        * pointer to function without an extra TAKE_ADDRESS operation */
+       if (!regular_take_address &&
+                       expr->reference.entity->kind != ENTITY_FUNCTION) {
+               return NULL;
+       }
+
+       return expr;
+}
+
+static void warn_reference_address_as_bool(expression_t const* expr)
+{
+       if (!warning.address)
+               return;
+
+       expr = get_reference_address(expr);
+       if (expr != NULL) {
+               warningf(&expr->base.source_position,
+                        "the address of '%Y' will always evaluate as 'true'",
+                        expr->reference.entity->base.symbol);
+       }
+}
+
 /**
  * Parse a conditional expression, ie. 'expression ? ... : ...'.
  *
@@ -7727,6 +7801,8 @@ static expression_t *parse_conditional_expression(expression_t *expression)
        conditional_expression_t *conditional = &result->conditional;
        conditional->condition                = expression;
 
+       warn_reference_address_as_bool(expression);
+
        eat('?');
        add_anchor_token(':');
 
@@ -8065,45 +8141,6 @@ static void semantic_unexpr_plus(unary_expression_t *expression)
                        "traditional C rejects the unary plus operator");
 }
 
-static expression_t const *get_reference_address(expression_t const *expr)
-{
-       bool regular_take_address = true;
-       for (;;) {
-               if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
-                       expr = expr->unary.value;
-               } else {
-                       regular_take_address = false;
-               }
-
-               if (expr->kind != EXPR_UNARY_DEREFERENCE)
-                       break;
-
-               expr = expr->unary.value;
-       }
-
-       /* special case for functions which are automatically converted to a
-        * pointer to function without an extra TAKE_ADDRESS operation */
-       if (!regular_take_address && expr->kind == EXPR_REFERENCE
-                       && expr->reference.entity->kind == ENTITY_FUNCTION) {
-               return expr;
-       }
-
-       return NULL;
-}
-
-static void warn_function_address_as_bool(expression_t const* expr)
-{
-       if (!warning.address)
-               return;
-
-       expr = get_reference_address(expr);
-       if (expr != NULL) {
-               warningf(&expr->base.source_position,
-                        "the address of '%Y' will always evaluate as 'true'",
-                        expr->reference.entity->base.symbol);
-       }
-}
-
 static void semantic_not(unary_expression_t *expression)
 {
        type_t *const orig_type = expression->value->base.type;
@@ -8113,7 +8150,7 @@ static void semantic_not(unary_expression_t *expression)
                       "operand of ! must be of scalar type");
        }
 
-       warn_function_address_as_bool(expression->value);
+       warn_reference_address_as_bool(expression->value);
 
        expression->base.type = c_mode & _CXX ? type_bool : type_int;
 }
@@ -8190,11 +8227,8 @@ static void semantic_take_addr(unary_expression_t *expression)
                return;
 
        /* Â§6.5.3.2 */
-       if (value->kind != EXPR_ARRAY_ACCESS
-                       && value->kind != EXPR_UNARY_DEREFERENCE
-                       && !is_lvalue(value)) {
-               errorf(&expression->base.source_position,
-                      "'&' requires an lvalue");
+       if (!is_lvalue(value)) {
+               errorf(&expression->base.source_position, "'&' requires an lvalue");
        }
        if (type->kind == TYPE_BITFIELD) {
                errorf(&expression->base.source_position,
@@ -8713,8 +8747,8 @@ static void semantic_logical_op(binary_expression_t *expression)
        type_t       *const type_left       = skip_typeref(orig_type_left);
        type_t       *const type_right      = skip_typeref(orig_type_right);
 
-       warn_function_address_as_bool(left);
-       warn_function_address_as_bool(right);
+       warn_reference_address_as_bool(left);
+       warn_reference_address_as_bool(right);
 
        if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
                /* TODO: improve error message */
@@ -9098,8 +9132,8 @@ static void init_expression_parsers(void)
  */
 static asm_argument_t *parse_asm_arguments(bool is_out)
 {
-       asm_argument_t *result = NULL;
-       asm_argument_t *last   = NULL;
+       asm_argument_t  *result = NULL;
+       asm_argument_t **anchor = &result;
 
        while (token.type == T_STRING_LITERAL || token.type == '[') {
                asm_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
@@ -9182,12 +9216,8 @@ static asm_argument_t *parse_asm_arguments(bool is_out)
 
                set_address_taken(expression, true);
 
-               if (last != NULL) {
-                       last->next = argument;
-               } else {
-                       result = argument;
-               }
-               last = argument;
+               *anchor = argument;
+               anchor  = &argument->next;
 
                if (token.type != ',')
                        break;
@@ -9479,12 +9509,8 @@ static statement_t *parse_label_statement(void)
        }
 
        /* remember the labels in a list for later checking */
-       if (label_last == NULL) {
-               label_first = &statement->label;
-       } else {
-               label_last->next = &statement->label;
-       }
-       label_last = &statement->label;
+       *label_anchor = &statement->label;
+       label_anchor  = &statement->label.next;
 
        POP_PARENT;
        return statement;
@@ -9507,6 +9533,7 @@ static statement_t *parse_if(void)
        add_anchor_token(')');
        expression_t *const expr = parse_expression();
        statement->ifs.condition = expr;
+       warn_reference_address_as_bool(expr);
        mark_vars_read(expr, NULL);
        rem_anchor_token(')');
        expect(')');
@@ -9647,6 +9674,7 @@ static statement_t *parse_while(void)
        add_anchor_token(')');
        expression_t *const cond = parse_expression();
        statement->whiles.condition = cond;
+       warn_reference_address_as_bool(cond);
        mark_vars_read(cond, NULL);
        rem_anchor_token(')');
        expect(')');
@@ -9680,6 +9708,7 @@ static statement_t *parse_do(void)
        add_anchor_token(')');
        expression_t *const cond = parse_expression();
        statement->do_while.condition = cond;
+       warn_reference_address_as_bool(cond);
        mark_vars_read(cond, NULL);
        rem_anchor_token(')');
        expect(')');
@@ -9732,6 +9761,7 @@ static statement_t *parse_for(void)
                add_anchor_token(';');
                expression_t *const cond = parse_expression();
                statement->fors.condition = cond;
+               warn_reference_address_as_bool(cond);
                mark_vars_read(cond, NULL);
                rem_anchor_token(';');
        }
@@ -9749,7 +9779,7 @@ static statement_t *parse_for(void)
        rem_anchor_token(')');
        statement->fors.body = parse_loop_body(statement);
 
-       assert(scope == &statement->fors.scope);
+       assert(current_scope == &statement->fors.scope);
        scope_pop();
        environment_pop_to(top);
 
@@ -9759,7 +9789,7 @@ static statement_t *parse_for(void)
 end_error:
        POP_PARENT;
        rem_anchor_token(')');
-       assert(scope == &statement->fors.scope);
+       assert(current_scope == &statement->fors.scope);
        scope_pop();
        environment_pop_to(top);
 
@@ -9779,8 +9809,8 @@ static statement_t *parse_goto(void)
                expression_t *expression = parse_expression();
                mark_vars_read(expression, NULL);
 
-               /* Argh: although documentation say the expression must be of type void *,
-                * gcc excepts anything that can be casted into void * without error */
+               /* Argh: although documentation says the expression must be of type void*,
+                * gcc accepts anything that can be casted into void* without error */
                type_t *type = expression->base.type;
 
                if (type != type_error_type) {
@@ -9811,12 +9841,8 @@ static statement_t *parse_goto(void)
        }
 
        /* remember the goto's in a list for later checking */
-       if (goto_last == NULL) {
-               goto_first = &statement->gotos;
-       } else {
-               goto_last->next = &statement->gotos;
-       }
-       goto_last = &statement->gotos;
+       *goto_anchor = &statement->gotos;
+       goto_anchor  = &statement->gotos.next;
 
        expect(';');
 
@@ -9945,7 +9971,7 @@ static statement_t *parse_return(void)
                mark_vars_read(return_value, NULL);
        }
 
-       const type_t *const func_type = current_function->base.type;
+       const type_t *const func_type = skip_typeref(current_function->base.type);
        assert(is_type_function(func_type));
        type_t *const return_type = skip_typeref(func_type->function.return_type);
 
@@ -9993,18 +10019,18 @@ static statement_t *parse_declaration_statement(void)
 {
        statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
 
-       entity_t *before = scope->last_entity;
+       entity_t *before = current_scope->last_entity;
        if (GNU_MODE)
                parse_external_declaration();
        else
                parse_declaration(record_entity);
 
        if (before == NULL) {
-               statement->declaration.declarations_begin = scope->entities;
+               statement->declaration.declarations_begin = current_scope->entities;
        } else {
                statement->declaration.declarations_begin = before->base.next;
        }
-       statement->declaration.declarations_end = scope->last_entity;
+       statement->declaration.declarations_end = current_scope->last_entity;
 
        return statement;
 }
@@ -10100,13 +10126,13 @@ static statement_t *parse_local_label_declaration(void)
                }
                symbol_t *symbol = token.v.symbol;
                entity_t *entity = get_entity(symbol, NAMESPACE_LABEL);
-               if (entity != NULL && entity->base.parent_scope == scope) {
+               if (entity != NULL && entity->base.parent_scope == current_scope) {
                        errorf(HERE, "multiple definitions of '__label__ %Y' (previous definition %P)",
                               symbol, &entity->base.source_position);
                } else {
                        entity = allocate_entity_zero(ENTITY_LOCAL_LABEL);
 
-                       entity->base.parent_scope    = scope;
+                       entity->base.parent_scope    = current_scope;
                        entity->base.namespc         = NAMESPACE_LABEL;
                        entity->base.source_position = token.source_position;
                        entity->base.symbol          = symbol;
@@ -10132,6 +10158,55 @@ end_error:
        return statement;
 }
 
+static void parse_namespace_definition(void)
+{
+       eat(T_namespace);
+
+       entity_t *entity = NULL;
+       symbol_t *symbol = NULL;
+
+       if (token.type == T_IDENTIFIER) {
+               symbol = token.v.symbol;
+               next_token();
+
+               entity = get_entity(symbol, NAMESPACE_NORMAL);
+               if (entity != NULL && entity->kind != ENTITY_NAMESPACE
+                               && entity->base.parent_scope == current_scope) {
+                       error_redefined_as_different_kind(&token.source_position,
+                                                         entity, ENTITY_NAMESPACE);
+                       entity = NULL;
+               }
+       }
+
+       if (entity == NULL) {
+               entity                       = allocate_entity_zero(ENTITY_NAMESPACE);
+               entity->base.symbol          = symbol;
+               entity->base.source_position = token.source_position;
+               entity->base.namespc         = NAMESPACE_NORMAL;
+               entity->base.parent_scope    = current_scope;
+       }
+
+       if (token.type == '=') {
+               /* TODO: parse namespace alias */
+               panic("namespace alias definition not supported yet");
+       }
+
+       environment_push(entity);
+       append_entity(current_scope, entity);
+
+       size_t const top = environment_top();
+       scope_push(&entity->namespacee.members);
+
+       expect('{');
+       parse_externals();
+       expect('}');
+
+end_error:
+       assert(current_scope == &entity->namespacee.members);
+       scope_pop();
+       environment_pop_to(top);
+}
+
 /**
  * Parse a statement.
  * There's also parse_statement() which additionally checks for
@@ -10195,22 +10270,22 @@ expression_statment:
                statement = parse_local_label_declaration();
                break;
 
-       case ';':        statement = parse_empty_statement();         break;
-       case '{':        statement = parse_compound_statement(false); break;
-       case T___leave:  statement = parse_leave_statement();         break;
-       case T___try:    statement = parse_ms_try_statment();         break;
-       case T_asm:      statement = parse_asm_statement();           break;
-       case T_break:    statement = parse_break();                   break;
-       case T_case:     statement = parse_case_statement();          break;
-       case T_continue: statement = parse_continue();                break;
-       case T_default:  statement = parse_default_statement();       break;
-       case T_do:       statement = parse_do();                      break;
-       case T_for:      statement = parse_for();                     break;
-       case T_goto:     statement = parse_goto();                    break;
-       case T_if:       statement = parse_if();                      break;
-       case T_return:   statement = parse_return();                  break;
-       case T_switch:   statement = parse_switch();                  break;
-       case T_while:    statement = parse_while();                   break;
+       case ';':         statement = parse_empty_statement();         break;
+       case '{':         statement = parse_compound_statement(false); break;
+       case T___leave:   statement = parse_leave_statement();         break;
+       case T___try:     statement = parse_ms_try_statment();         break;
+       case T_asm:       statement = parse_asm_statement();           break;
+       case T_break:     statement = parse_break();                   break;
+       case T_case:      statement = parse_case_statement();          break;
+       case T_continue:  statement = parse_continue();                break;
+       case T_default:   statement = parse_default_statement();       break;
+       case T_do:        statement = parse_do();                      break;
+       case T_for:       statement = parse_for();                     break;
+       case T_goto:      statement = parse_goto();                    break;
+       case T_if:        statement = parse_if();                      break;
+       case T_return:    statement = parse_return();                  break;
+       case T_switch:    statement = parse_switch();                  break;
+       case T_while:     statement = parse_while();                   break;
 
        EXPRESSION_START
                statement = parse_expression_statement();
@@ -10322,7 +10397,7 @@ static statement_t *parse_compound_statement(bool inside_expression_statement)
 
 end_error:
        rem_anchor_token('}');
-       assert(scope == &statement->compound.scope);
+       assert(current_scope == &statement->compound.scope);
        scope_pop();
        environment_pop_to(top);
 
@@ -10384,18 +10459,94 @@ static void parse_global_asm(void)
 end_error:;
 }
 
-/**
- * Parse a translation unit.
- */
-static void parse_translation_unit(void)
+static void parse_linkage_specification(void)
+{
+       eat(T_extern);
+       assert(token.type == T_STRING_LITERAL);
+
+       const char *linkage = parse_string_literals().begin;
+
+       linkage_kind_t old_linkage = current_linkage;
+       linkage_kind_t new_linkage;
+       if (strcmp(linkage, "C") == 0) {
+               new_linkage = LINKAGE_C;
+       } else if (strcmp(linkage, "C++") == 0) {
+               new_linkage = LINKAGE_CXX;
+       } else {
+               errorf(HERE, "linkage string \"%s\" not recognized", linkage);
+               new_linkage = LINKAGE_INVALID;
+       }
+       current_linkage = new_linkage;
+
+       if (token.type == '{') {
+               next_token();
+               parse_externals();
+               expect('}');
+       } else {
+               parse_external();
+       }
+
+end_error:
+       assert(current_linkage == new_linkage);
+       current_linkage = old_linkage;
+}
+
+static void parse_external(void)
+{
+       switch (token.type) {
+               DECLARATION_START_NO_EXTERN
+               case T_IDENTIFIER:
+               case T___extension__:
+               case '(': /* for function declarations with implicit return type and
+                                  * parenthesized declarator, i.e. (f)(void); */
+                       parse_external_declaration();
+                       return;
+
+               case T_extern:
+                       if (look_ahead(1)->type == T_STRING_LITERAL) {
+                               parse_linkage_specification();
+                       } else {
+                               parse_external_declaration();
+                       }
+                       return;
+
+               case T_asm:
+                       parse_global_asm();
+                       return;
+
+               case T_namespace:
+                       parse_namespace_definition();
+                       return;
+
+               case ';':
+                       if (!strict_mode) {
+                               if (warning.other)
+                                       warningf(HERE, "stray ';' outside of function");
+                               next_token();
+                               return;
+                       }
+                       /* FALLTHROUGH */
+
+               default:
+                       errorf(HERE, "stray %K outside of function", &token);
+                       if (token.type == '(' || token.type == '{' || token.type == '[')
+                               eat_until_matching_token(token.type);
+                       next_token();
+                       return;
+       }
+}
+
+static void parse_externals(void)
 {
+       add_anchor_token('}');
        add_anchor_token(T_EOF);
 
 #ifndef NDEBUG
        unsigned char token_anchor_copy[T_LAST_TOKEN];
        memcpy(token_anchor_copy, token_anchor_set, sizeof(token_anchor_copy));
 #endif
-       for (;;) {
+
+       while (token.type != T_EOF && token.type != '}') {
 #ifndef NDEBUG
                bool anchor_leak = false;
                for (int i = 0; i != T_LAST_TOKEN; ++i) {
@@ -10414,37 +10565,30 @@ static void parse_translation_unit(void)
                        abort();
 #endif
 
-               switch (token.type) {
-                       DECLARATION_START
-                       case T_IDENTIFIER:
-                       case T___extension__:
-                               parse_external_declaration();
-                               break;
+               parse_external();
+       }
 
-                       case T_asm:
-                               parse_global_asm();
-                               break;
+       rem_anchor_token(T_EOF);
+       rem_anchor_token('}');
+}
 
-                       case T_EOF:
-                               rem_anchor_token(T_EOF);
-                               return;
+/**
+ * Parse a translation unit.
+ */
+static void parse_translation_unit(void)
+{
+       add_anchor_token(T_EOF);
 
-                       case ';':
-                               if (!strict_mode) {
-                                       if (warning.other)
-                                               warningf(HERE, "stray ';' outside of function");
-                                       next_token();
-                                       break;
-                               }
-                               /* FALLTHROUGH */
+       while (true) {
+               parse_externals();
 
-                       default:
-                               errorf(HERE, "stray %K outside of function", &token);
-                               if (token.type == '(' || token.type == '{' || token.type == '[')
-                                       eat_until_matching_token(token.type);
-                               next_token();
-                               break;
-               }
+               if (token.type == T_EOF)
+                       break;
+
+               errorf(HERE, "stray %K outside of function", &token);
+               if (token.type == '(' || token.type == '{' || token.type == '[')
+                       eat_until_matching_token(token.type);
+               next_token();
        }
 }
 
@@ -10470,15 +10614,15 @@ void start_parsing(void)
        assert(file_scope == NULL);
        file_scope = &unit->scope;
 
-       assert(scope == NULL);
+       assert(current_scope == NULL);
        scope_push(&unit->scope);
 }
 
 translation_unit_t *finish_parsing(void)
 {
        /* do NOT use scope_pop() here, this will crash, will it by hand */
-       assert(scope == &unit->scope);
-       scope            = NULL;
+       assert(current_scope == &unit->scope);
+       current_scope = NULL;
 
        assert(file_scope == &unit->scope);
        check_unused_globals();
@@ -10498,6 +10642,7 @@ void parse(void)
        for (int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
                next_token();
        }
+       current_linkage = c_mode & _CXX ? LINKAGE_CXX : LINKAGE_C;
        parse_translation_unit();
 }