Merge T_WIDE_CHARACTER_CONSTANT into T_CHARACTER_CONSTANT.
[cparser] / ast2firm.c
index b7a637b..8a02168 100644 (file)
@@ -175,7 +175,6 @@ ir_mode *atomic_modes[ATOMIC_TYPE_LAST+1];
 
 static ir_node *_expression_to_firm(const expression_t *expression);
 static ir_node *expression_to_firm(const expression_t *expression);
-static void create_local_declaration(entity_t *entity);
 
 static unsigned decide_modulo_shift(unsigned type_size)
 {
@@ -855,6 +854,27 @@ void set_create_ld_ident(ident *(*func)(entity_t*))
        create_ld_ident = func;
 }
 
+static bool declaration_is_definition(const entity_t *entity)
+{
+       switch (entity->kind) {
+       case ENTITY_VARIABLE:
+               return entity->declaration.storage_class != STORAGE_CLASS_EXTERN;
+       case ENTITY_FUNCTION:
+               return entity->function.statement != NULL;
+       case ENTITY_PARAMETER:
+       case ENTITY_COMPOUND_MEMBER:
+               return false;
+       case ENTITY_TYPEDEF:
+       case ENTITY_ENUM:
+       case ENTITY_ENUM_VALUE:
+       case ENTITY_NAMESPACE:
+       case ENTITY_LABEL:
+       case ENTITY_LOCAL_LABEL:
+               break;
+       }
+       panic("declaration_is_definition called on non-declaration");
+}
+
 /**
  * Handle GNU attributes for entities
  *
@@ -874,10 +894,11 @@ static void handle_decl_modifiers(ir_entity *irentity, entity_t *entity)
                        add_entity_additional_properties(irentity, mtp_property_const);
                }
        }
-       if (modifiers & DM_USED) {
+       if ((modifiers & DM_USED) && declaration_is_definition(entity)) {
                add_entity_linkage(irentity, IR_LINKAGE_HIDDEN_USER);
        }
-       if (modifiers & DM_WEAK) {
+       if ((modifiers & DM_WEAK) && declaration_is_definition(entity)
+           && entity->declaration.storage_class != STORAGE_CLASS_EXTERN) {
                add_entity_linkage(irentity, IR_LINKAGE_WEAK);
        }
 }
@@ -920,18 +941,6 @@ static ir_entity *get_function_entity(entity_t *entity, ir_type *owner_type)
                return NULL;
        }
 
-       if (is_main(entity)) {
-               /* force main to C linkage */
-               type_t *type = entity->declaration.type;
-               assert(is_type_function(type));
-               if (type->function.linkage != LINKAGE_C) {
-                       type_t *new_type           = duplicate_type(type);
-                       new_type->function.linkage = LINKAGE_C;
-                       type                       = identify_new_type(new_type);
-                       entity->declaration.type   = type;
-               }
-       }
-
        symbol_t *symbol = entity->base.symbol;
        ident    *id     = new_id_from_str(symbol->string);
 
@@ -939,10 +948,6 @@ static ir_entity *get_function_entity(entity_t *entity, ir_type *owner_type)
        ir_entity *irentity = entitymap_get(&entitymap, symbol);
        bool const has_body = entity->function.statement != NULL;
        if (irentity != NULL) {
-               if (get_entity_visibility(irentity) == ir_visibility_external
-                               && has_body) {
-                       set_entity_visibility(irentity, ir_visibility_default);
-               }
                goto entity_created;
        }
 
@@ -971,24 +976,22 @@ static ir_entity *get_function_entity(entity_t *entity, ir_type *owner_type)
        handle_decl_modifiers(irentity, entity);
 
        if (! nested_function) {
-               /* static inline             => local
-                * extern inline             => local
-                * inline without definition => local
-                * inline with definition    => external_visible */
                storage_class_tag_t const storage_class
                        = (storage_class_tag_t) entity->declaration.storage_class;
-               bool                const is_inline     = entity->function.is_inline;
-
-               if (is_inline && storage_class == STORAGE_CLASS_NONE && has_body) {
-                   set_entity_visibility(irentity, ir_visibility_default);
-               } else if (storage_class == STORAGE_CLASS_STATIC ||
-                          (is_inline && has_body)) {
+               if (storage_class == STORAGE_CLASS_STATIC) {
                    set_entity_visibility(irentity, ir_visibility_local);
-               } else if (has_body) {
-                   set_entity_visibility(irentity, ir_visibility_default);
                } else {
                    set_entity_visibility(irentity, ir_visibility_external);
                }
+
+               bool const is_inline = entity->function.is_inline;
+               if (is_inline && has_body) {
+                       if (((c_mode & _C99) && storage_class == STORAGE_CLASS_NONE)
+                           || ((c_mode & _C99) == 0
+                               && storage_class == STORAGE_CLASS_EXTERN)) {
+                               add_entity_linkage(irentity, IR_LINKAGE_NO_CODEGEN);
+                       }
+               }
        } else {
                /* nested functions are always local */
                set_entity_visibility(irentity, ir_visibility_local);
@@ -1183,8 +1186,7 @@ static ir_node *string_to_firm(const source_position_t *const src_pos,
        return create_symconst(dbgi, entity);
 }
 
-static bool try_create_integer(literal_expression_t *literal,
-                               type_t *type, unsigned char base)
+static bool try_create_integer(literal_expression_t *literal, type_t *type)
 {
        const char *string = literal->value.begin;
        size_t      size   = literal->value.size;
@@ -1192,8 +1194,8 @@ static bool try_create_integer(literal_expression_t *literal,
        assert(type->kind == TYPE_ATOMIC);
        atomic_type_kind_t akind = type->atomic.akind;
 
-       ir_mode   *mode = atomic_modes[akind];
-       ir_tarval *tv   = new_integer_tarval_from_str(string, size, 1, base, mode);
+       ir_mode   *const mode = atomic_modes[akind];
+       ir_tarval *const tv   = new_tarval_from_str(string, size, mode);
        if (tv == tarval_bad)
                return false;
 
@@ -1204,53 +1206,44 @@ static bool try_create_integer(literal_expression_t *literal,
 
 static void create_integer_tarval(literal_expression_t *literal)
 {
-       unsigned        us     = 0;
+       /* -1: signed only, 0: any, 1: unsigned only */
+       int             sign   = literal->value.begin[0] != '0' /* decimal */ ? -1 : 0;
        unsigned        ls     = 0;
        const string_t *suffix = &literal->suffix;
        /* parse suffix */
        if (suffix->size > 0) {
                for (const char *c = suffix->begin; *c != '\0'; ++c) {
-                       if (*c == 'u' || *c == 'U') { ++us; }
+                       if (*c == 'u' || *c == 'U') sign = 1;
                        if (*c == 'l' || *c == 'L') { ++ls; }
                }
        }
 
-       unsigned base;
-       switch (literal->base.kind) {
-               case EXPR_LITERAL_INTEGER_OCTAL:       base =  8; break;
-               case EXPR_LITERAL_INTEGER:             base = 10; break;
-               case EXPR_LITERAL_INTEGER_HEXADECIMAL: base = 16; break;
-               default: panic("invalid literal kind");
-       }
-
        tarval_int_overflow_mode_t old_mode = tarval_get_integer_overflow_mode();
 
        /* now try if the constant is small enough for some types */
        tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
        if (ls < 1) {
-               if (us == 0 && try_create_integer(literal, type_int, base))
+               if (sign <= 0 && try_create_integer(literal, type_int))
                        goto finished;
-               if ((us == 1 || base != 10)
-                               && try_create_integer(literal, type_unsigned_int, base))
+               if (sign >= 0 && try_create_integer(literal, type_unsigned_int))
                        goto finished;
        }
        if (ls < 2) {
-               if (us == 0 && try_create_integer(literal, type_long, base))
+               if (sign <= 0 && try_create_integer(literal, type_long))
                        goto finished;
-               if ((us == 1 || base != 10)
-                               && try_create_integer(literal, type_unsigned_long, base))
+               if (sign >= 0 && try_create_integer(literal, type_unsigned_long))
                        goto finished;
        }
        /* last try? then we should not report tarval_bad */
-       if (us != 1 && base == 10)
+       if (sign < 0)
                tarval_set_integer_overflow_mode(TV_OVERFLOW_WRAP);
-       if (us == 0 && try_create_integer(literal, type_long_long, base))
+       if (sign <= 0 && try_create_integer(literal, type_long_long))
                goto finished;
 
        /* last try */
-       assert(us == 1 || base != 10);
+       assert(sign >= 0);
        tarval_set_integer_overflow_mode(TV_OVERFLOW_WRAP);
-       bool res = try_create_integer(literal, type_unsigned_long_long, base);
+       bool res = try_create_integer(literal, type_unsigned_long_long);
        if (!res)
                panic("internal error when parsing number literal");
 
@@ -1262,8 +1255,6 @@ void determine_literal_type(literal_expression_t *literal)
 {
        switch (literal->base.kind) {
        case EXPR_LITERAL_INTEGER:
-       case EXPR_LITERAL_INTEGER_OCTAL:
-       case EXPR_LITERAL_INTEGER_HEXADECIMAL:
                create_integer_tarval(literal);
                return;
        default:
@@ -1289,8 +1280,9 @@ static ir_node *literal_to_firm(const literal_expression_t *literal)
                size_t len = snprintf(buf, sizeof(buf), UTF32_PRINTF_FORMAT, v);
 
                tv = new_tarval_from_str(buf, len, mode);
-               goto make_const;
+               break;
        }
+
        case EXPR_LITERAL_CHARACTER: {
                long long int v;
                bool char_is_signed
@@ -1307,41 +1299,32 @@ static ir_node *literal_to_firm(const literal_expression_t *literal)
                size_t len = snprintf(buf, sizeof(buf), "%lld", v);
 
                tv = new_tarval_from_str(buf, len, mode);
-               goto make_const;
+               break;
        }
+
        case EXPR_LITERAL_INTEGER:
-       case EXPR_LITERAL_INTEGER_OCTAL:
-       case EXPR_LITERAL_INTEGER_HEXADECIMAL:
                assert(literal->target_value != NULL);
                tv = literal->target_value;
-               goto make_const;
+               break;
+
        case EXPR_LITERAL_FLOATINGPOINT:
                tv = new_tarval_from_str(string, size, mode);
-               goto make_const;
-       case EXPR_LITERAL_FLOATINGPOINT_HEXADECIMAL: {
-               char buffer[size + 2];
-               memcpy(buffer, "0x", 2);
-               memcpy(buffer+2, string, size);
-               tv = new_tarval_from_str(buffer, size+2, mode);
-               goto make_const;
-       }
+               break;
+
        case EXPR_LITERAL_BOOLEAN:
                if (string[0] == 't') {
                        tv = get_mode_one(mode);
                } else {
                        assert(string[0] == 'f');
+       case EXPR_LITERAL_MS_NOOP:
                        tv = get_mode_null(mode);
                }
-               goto make_const;
-       case EXPR_LITERAL_MS_NOOP:
-               tv = get_mode_null(mode);
-               goto make_const;
-       default:
                break;
+
+       default:
+               panic("Invalid literal kind found");
        }
-       panic("Invalid literal kind found");
 
-make_const: ;
        dbg_info *dbgi       = get_dbg_info(&literal->base.source_position);
        ir_node  *res        = new_d_Const(dbgi, tv);
        ir_mode  *mode_arith = get_ir_mode_arithmetic(type);
@@ -1532,15 +1515,11 @@ static ir_node *enum_constant_to_firm(reference_expression_t const *const ref)
        return new_Const(entity->enum_value.tv);
 }
 
-static ir_node *reference_expression_to_firm(const reference_expression_t *ref)
+static ir_node *reference_addr(const reference_expression_t *ref)
 {
        dbg_info *dbgi   = get_dbg_info(&ref->base.source_position);
        entity_t *entity = ref->entity;
        assert(is_declaration(entity));
-       type_t   *type   = skip_typeref(entity->declaration.type);
-
-       /* make sure the type is constructed */
-       (void) get_ir_type(type);
 
        if (entity->kind == ENTITY_FUNCTION
            && entity->function.btk != BUILTIN_NONE) {
@@ -1549,8 +1528,7 @@ static ir_node *reference_expression_to_firm(const reference_expression_t *ref)
                 * builtins which don't have entities */
                if (irentity == NULL) {
                        source_position_t const *const pos = &ref->base.source_position;
-                       symbol_t          const *const sym = ref->entity->base.symbol;
-                       warningf(WARN_OTHER, pos, "taking address of builtin '%Y'", sym);
+                       warningf(WARN_OTHER, pos, "taking address of builtin '%N'", ref->entity);
 
                        /* simply create a NULL pointer */
                        ir_mode  *mode = get_ir_mode_arithmetic(type_void_ptr);
@@ -1560,68 +1538,6 @@ static ir_node *reference_expression_to_firm(const reference_expression_t *ref)
                }
        }
 
-       switch ((declaration_kind_t) entity->declaration.kind) {
-       case DECLARATION_KIND_UNKNOWN:
-               break;
-
-       case DECLARATION_KIND_LOCAL_VARIABLE: {
-               ir_mode *const mode  = get_ir_mode_storage(type);
-               ir_node *const value = get_value(entity->variable.v.value_number, mode);
-               return create_conv(NULL, value, get_ir_mode_arithmetic(type));
-       }
-       case DECLARATION_KIND_PARAMETER: {
-               ir_mode *const mode  = get_ir_mode_storage(type);
-               ir_node *const value = get_value(entity->parameter.v.value_number,mode);
-               return create_conv(NULL, value, get_ir_mode_arithmetic(type));
-       }
-       case DECLARATION_KIND_FUNCTION: {
-               return create_symconst(dbgi, entity->function.irentity);
-       }
-       case DECLARATION_KIND_INNER_FUNCTION: {
-               ir_mode *const mode = get_ir_mode_storage(type);
-               if (!entity->function.goto_to_outer && !entity->function.need_closure) {
-                       /* inner function not using the closure */
-                       return create_symconst(dbgi, entity->function.irentity);
-               } else {
-                       /* need trampoline here */
-                       return create_trampoline(dbgi, mode, entity->function.irentity);
-               }
-       }
-       case DECLARATION_KIND_GLOBAL_VARIABLE: {
-               const variable_t *variable = &entity->variable;
-               ir_node *const addr = create_symconst(dbgi, variable->v.entity);
-               return deref_address(dbgi, variable->base.type, addr);
-       }
-
-       case DECLARATION_KIND_LOCAL_VARIABLE_ENTITY: {
-               ir_entity *irentity = entity->variable.v.entity;
-               ir_node   *frame    = get_local_frame(irentity);
-               ir_node   *sel = new_d_simpleSel(dbgi, new_NoMem(), frame, irentity);
-               return deref_address(dbgi, entity->declaration.type, sel);
-       }
-       case DECLARATION_KIND_PARAMETER_ENTITY: {
-               ir_entity *irentity = entity->parameter.v.entity;
-               ir_node   *frame    = get_local_frame(irentity);
-               ir_node   *sel = new_d_simpleSel(dbgi, new_NoMem(), frame, irentity);
-               return deref_address(dbgi, entity->declaration.type, sel);
-       }
-
-       case DECLARATION_KIND_VARIABLE_LENGTH_ARRAY:
-               return entity->variable.v.vla_base;
-
-       case DECLARATION_KIND_COMPOUND_MEMBER:
-               panic("not implemented reference type");
-       }
-
-       panic("reference to declaration with unknown type found");
-}
-
-static ir_node *reference_addr(const reference_expression_t *ref)
-{
-       dbg_info *dbgi   = get_dbg_info(&ref->base.source_position);
-       entity_t *entity = ref->entity;
-       assert(is_declaration(entity));
-
        switch((declaration_kind_t) entity->declaration.kind) {
        case DECLARATION_KIND_UNKNOWN:
                break;
@@ -1634,18 +1550,12 @@ static ir_node *reference_addr(const reference_expression_t *ref)
                ir_node *const addr = create_symconst(dbgi, entity->variable.v.entity);
                return addr;
        }
-       case DECLARATION_KIND_LOCAL_VARIABLE_ENTITY: {
-               ir_entity *irentity = entity->variable.v.entity;
-               ir_node   *frame    = get_local_frame(irentity);
-               ir_node   *sel = new_d_simpleSel(dbgi, new_NoMem(), frame, irentity);
 
-               return sel;
-       }
+       case DECLARATION_KIND_LOCAL_VARIABLE_ENTITY:
        case DECLARATION_KIND_PARAMETER_ENTITY: {
-               ir_entity *irentity = entity->parameter.v.entity;
+               ir_entity *irentity = entity->variable.v.entity;
                ir_node   *frame    = get_local_frame(irentity);
                ir_node   *sel = new_d_simpleSel(dbgi, new_NoMem(), frame, irentity);
-
                return sel;
        }
 
@@ -1675,6 +1585,28 @@ static ir_node *reference_addr(const reference_expression_t *ref)
        panic("reference to declaration with unknown type found");
 }
 
+static ir_node *reference_expression_to_firm(const reference_expression_t *ref)
+{
+       dbg_info *const dbgi   = get_dbg_info(&ref->base.source_position);
+       entity_t *const entity = ref->entity;
+       assert(is_declaration(entity));
+
+       switch ((declaration_kind_t)entity->declaration.kind) {
+       case DECLARATION_KIND_LOCAL_VARIABLE:
+       case DECLARATION_KIND_PARAMETER: {
+               type_t  *const type  = skip_typeref(entity->declaration.type);
+               ir_mode *const mode  = get_ir_mode_storage(type);
+               ir_node *const value = get_value(entity->variable.v.value_number, mode);
+               return create_conv(dbgi, value, get_ir_mode_arithmetic(type));
+       }
+
+       default: {
+               ir_node *const addr = reference_addr(ref);
+               return deref_address(dbgi, entity->declaration.type, addr);
+       }
+       }
+}
+
 /**
  * Transform calls to builtin functions.
  */
@@ -2104,12 +2036,10 @@ static ir_node *set_value_for_expression_addr(const expression_t *expression,
                entity_t *entity = ref->entity;
                assert(is_declaration(entity));
                assert(entity->declaration.kind != DECLARATION_KIND_UNKNOWN);
-               if (entity->declaration.kind == DECLARATION_KIND_LOCAL_VARIABLE) {
+               if (entity->declaration.kind == DECLARATION_KIND_LOCAL_VARIABLE ||
+                   entity->declaration.kind == DECLARATION_KIND_PARAMETER) {
                        set_value(entity->variable.v.value_number, value);
                        return value;
-               } else if (entity->declaration.kind == DECLARATION_KIND_PARAMETER) {
-                       set_value(entity->parameter.v.value_number, value);
-                       return value;
                }
        }
 
@@ -2155,20 +2085,14 @@ static ir_node *get_value_from_lvalue(const expression_t *expression,
                                || entity->kind == ENTITY_PARAMETER);
                assert(entity->declaration.kind != DECLARATION_KIND_UNKNOWN);
                int value_number;
-               if (entity->declaration.kind == DECLARATION_KIND_LOCAL_VARIABLE) {
+               if (entity->declaration.kind == DECLARATION_KIND_LOCAL_VARIABLE ||
+                   entity->declaration.kind == DECLARATION_KIND_PARAMETER) {
                        value_number = entity->variable.v.value_number;
                        assert(addr == NULL);
                        type_t  *type = skip_typeref(expression->base.type);
                        ir_mode *mode = get_ir_mode_storage(type);
                        ir_node *res  = get_value(value_number, mode);
                        return create_conv(NULL, res, get_ir_mode_arithmetic(type));
-               } else if (entity->declaration.kind == DECLARATION_KIND_PARAMETER) {
-                       value_number = entity->parameter.v.value_number;
-                       assert(addr == NULL);
-                       type_t  *type = skip_typeref(expression->base.type);
-                       ir_mode *mode = get_ir_mode_storage(type);
-                       ir_node *res  = get_value(value_number, mode);
-                       return create_conv(NULL, res, get_ir_mode_arithmetic(type));
                }
        }
 
@@ -2945,12 +2869,7 @@ static ir_node *alignof_to_firm(const typeprop_expression_t *expression)
        if (tp_expression != NULL) {
                entity_t *entity = get_expression_entity(tp_expression);
                if (entity != NULL) {
-                       if (entity->kind == ENTITY_FUNCTION) {
-                               /* a gnu-extension */
-                               alignment = 1;
-                       } else {
-                               alignment = get_cparser_entity_alignment(entity);
-                       }
+                       alignment = get_cparser_entity_alignment(entity);
                }
        }
 
@@ -2983,7 +2902,8 @@ static ir_tarval *fold_constant_to_tarval(const expression_t *expression)
        ir_graph *old_current_ir_graph = current_ir_graph;
        current_ir_graph = get_const_code_irg();
 
-       ir_node *cnst = expression_to_firm(expression);
+       ir_node *const cnst = _expression_to_firm(expression);
+
        current_ir_graph = old_current_ir_graph;
        set_optimize(old_optimize);
        set_opt_constant_folding(old_constant_folding);
@@ -2994,7 +2914,9 @@ static ir_tarval *fold_constant_to_tarval(const expression_t *expression)
 
        constant_folding = constant_folding_old;
 
-       return get_Const_tarval(cnst);
+       ir_tarval *const tv   = get_Const_tarval(cnst);
+       ir_mode   *const mode = get_ir_mode_arithmetic(skip_typeref(expression->base.type));
+       return tarval_convert_to(tv, mode);
 }
 
 /* this function is only used in parser.c, but it relies on libfirm functionality */
@@ -3503,13 +3425,7 @@ static ir_node *expression_to_firm(const expression_t *expression)
        }
 
        if (is_constant_expression(expression) == EXPR_CLASS_CONSTANT) {
-               bool const constant_folding_old = constant_folding;
-               constant_folding = true;
-               ir_node *res  = _expression_to_firm(expression);
-               constant_folding = constant_folding_old;
-               ir_mode *mode = get_ir_mode_arithmetic(expression->base.type);
-               assert(is_Const(res));
-               return create_Const_from_bool(mode, !is_Const_null(res));
+               return new_Const(fold_constant_to_tarval(expression));
        }
 
        /* we have to produce a 0/1 from the mode_b expression */
@@ -4414,6 +4330,11 @@ static void create_local_static_variable(entity_t *entity)
        set_entity_ld_ident(irentity, id);
        set_entity_visibility(irentity, ir_visibility_local);
 
+       if (entity->variable.initializer == NULL) {
+               ir_initializer_t *null_init = get_initializer_null();
+               set_entity_initializer(irentity, null_init);
+       }
+
        ir_graph *const old_current_ir_graph = current_ir_graph;
        current_ir_graph = get_const_code_irg();
 
@@ -4467,15 +4388,11 @@ static ir_node *expression_statement_to_firm(expression_statement_t *statement)
        return expression_to_firm(statement->expression);
 }
 
+static void create_local_declarations(entity_t*);
+
 static ir_node *compound_statement_to_firm(compound_statement_t *compound)
 {
-       entity_t *entity = compound->scope.entities;
-       for ( ; entity != NULL; entity = entity->base.next) {
-               if (!is_declaration(entity))
-                       continue;
-
-               create_local_declaration(entity);
-       }
+       create_local_declarations(compound->scope.entities);
 
        ir_node     *result    = NULL;
        statement_t *statement = compound->statements;
@@ -4488,36 +4405,44 @@ static ir_node *compound_statement_to_firm(compound_statement_t *compound)
 
 static void create_global_variable(entity_t *entity)
 {
-       ir_linkage    linkage    = IR_LINKAGE_DEFAULT;
-       ir_visibility visibility = ir_visibility_default;
-       ir_entity    *irentity;
+       ir_linkage          linkage    = IR_LINKAGE_DEFAULT;
+       ir_visibility       visibility = ir_visibility_external;
+       storage_class_tag_t storage
+               = (storage_class_tag_t)entity->declaration.storage_class;
+       decl_modifiers_t    modifiers  = entity->declaration.modifiers;
        assert(entity->kind == ENTITY_VARIABLE);
 
-       switch ((storage_class_tag_t)entity->declaration.storage_class) {
+       switch (storage) {
        case STORAGE_CLASS_EXTERN: visibility = ir_visibility_external; break;
        case STORAGE_CLASS_STATIC: visibility = ir_visibility_local;    break;
-       case STORAGE_CLASS_NONE:
-               visibility = ir_visibility_default;
-               /* uninitialized globals get merged in C */
-               if (entity->variable.initializer == NULL)
-                       linkage |= IR_LINKAGE_MERGE;
-               break;
+       case STORAGE_CLASS_NONE:   visibility = ir_visibility_external; break;
        case STORAGE_CLASS_TYPEDEF:
        case STORAGE_CLASS_AUTO:
        case STORAGE_CLASS_REGISTER:
                panic("invalid storage class for global var");
        }
 
+       /* "common" symbols */
+       if (storage == STORAGE_CLASS_NONE
+           && entity->variable.initializer == NULL
+           && !entity->variable.thread_local
+           && (modifiers & DM_WEAK) == 0) {
+               linkage |= IR_LINKAGE_MERGE;
+       }
+
        ir_type *var_type = get_glob_type();
        if (entity->variable.thread_local) {
                var_type = get_tls_type();
-               /* LINKAGE_MERGE not supported by current linkers */
-               linkage &= ~IR_LINKAGE_MERGE;
        }
        create_variable_entity(entity, DECLARATION_KIND_GLOBAL_VARIABLE, var_type);
-       irentity = entity->variable.v.entity;
+       ir_entity *irentity = entity->variable.v.entity;
        add_entity_linkage(irentity, linkage);
        set_entity_visibility(irentity, visibility);
+       if (entity->variable.initializer == NULL
+           && storage != STORAGE_CLASS_EXTERN) {
+               ir_initializer_t *null_init = get_initializer_null();
+               set_entity_initializer(irentity, null_init);
+       }
 }
 
 static void create_local_declaration(entity_t *entity)
@@ -4569,6 +4494,14 @@ static void create_local_declaration(entity_t *entity)
        panic("invalid storage class found");
 }
 
+static void create_local_declarations(entity_t *e)
+{
+       for (; e; e = e->base.next) {
+               if (is_declaration(e))
+                       create_local_declaration(e);
+       }
+}
+
 static void initialize_local_declaration(entity_t *entity)
 {
        if (entity->base.symbol == NULL)
@@ -4632,6 +4565,8 @@ static ir_node *declaration_statement_to_firm(declaration_statement_t *statement
 
 static ir_node *if_statement_to_firm(if_statement_t *statement)
 {
+       create_local_declarations(statement->scope.entities);
+
        /* Create the condition. */
        ir_node *true_block  = NULL;
        ir_node *false_block = NULL;
@@ -4695,6 +4630,8 @@ static void jump_if_reachable(ir_node *const target_block)
 
 static ir_node *while_statement_to_firm(while_statement_t *statement)
 {
+       create_local_declarations(statement->scope.entities);
+
        /* Create the header block */
        ir_node *const header_block = new_immBlock();
        jump_to(header_block);
@@ -4754,6 +4691,8 @@ static ir_node *get_break_label(void)
 
 static ir_node *do_while_statement_to_firm(do_while_statement_t *statement)
 {
+       create_local_declarations(statement->scope.entities);
+
        /* create the header block */
        ir_node *header_block = new_immBlock();
 
@@ -4790,17 +4729,10 @@ static ir_node *do_while_statement_to_firm(do_while_statement_t *statement)
 
 static ir_node *for_statement_to_firm(for_statement_t *statement)
 {
-       /* create declarations */
-       entity_t *entity = statement->scope.entities;
-       for ( ; entity != NULL; entity = entity->base.next) {
-               if (!is_declaration(entity))
-                       continue;
-
-               create_local_declaration(entity);
-       }
+       create_local_declarations(statement->scope.entities);
 
        if (currently_reachable()) {
-               entity = statement->scope.entities;
+               entity_t *entity = statement->scope.entities;
                for ( ; entity != NULL; entity = entity->base.next) {
                        if (!is_declaration(entity))
                                continue;
@@ -5319,20 +5251,9 @@ static int count_local_variables(const entity_t *entity,
        int count = 0;
        entity_t const *const end = last != NULL ? last->base.next : NULL;
        for (; entity != end; entity = entity->base.next) {
-               type_t *type;
-               bool    address_taken;
-
-               if (entity->kind == ENTITY_VARIABLE) {
-                       type          = skip_typeref(entity->declaration.type);
-                       address_taken = entity->variable.address_taken;
-               } else if (entity->kind == ENTITY_PARAMETER) {
-                       type          = skip_typeref(entity->declaration.type);
-                       address_taken = entity->parameter.address_taken;
-               } else {
-                       continue;
-               }
-
-               if (!address_taken && is_type_scalar(type))
+               if ((entity->kind == ENTITY_VARIABLE || entity->kind == ENTITY_PARAMETER) &&
+                   !entity->variable.address_taken                                       &&
+                   is_type_scalar(skip_typeref(entity->declaration.type)))
                        ++count;
        }
        return count;
@@ -5408,20 +5329,16 @@ static void initialize_function_parameters(entity_t *entity)
                assert(parameter->declaration.kind == DECLARATION_KIND_UNKNOWN);
                type_t *type = skip_typeref(parameter->declaration.type);
 
-               bool needs_entity = parameter->parameter.address_taken;
                assert(!is_type_array(type));
-               if (is_type_compound(type)) {
-                       needs_entity = true;
-               }
+               bool const needs_entity = parameter->variable.address_taken || is_type_compound(type);
 
                ir_type *param_irtype = get_method_param_type(function_irtype, n);
                if (needs_entity) {
                        ir_type   *frame_type = get_irg_frame_type(irg);
                        ir_entity *param
                                = new_parameter_entity(frame_type, n, param_irtype);
-                       parameter->declaration.kind
-                               = DECLARATION_KIND_PARAMETER_ENTITY;
-                       parameter->parameter.v.entity = param;
+                       parameter->declaration.kind  = DECLARATION_KIND_PARAMETER_ENTITY;
+                       parameter->variable.v.entity = param;
                        continue;
                }
 
@@ -5433,13 +5350,13 @@ static void initialize_function_parameters(entity_t *entity)
                value = create_conv(NULL, value, mode);
                value = do_strict_conv(NULL, value);
 
-               parameter->declaration.kind         = DECLARATION_KIND_PARAMETER;
-               parameter->parameter.v.value_number = next_value_number_function;
+               parameter->declaration.kind        = DECLARATION_KIND_PARAMETER;
+               parameter->variable.v.value_number = next_value_number_function;
                set_irg_loc_description(current_ir_graph, next_value_number_function,
                                        parameter);
                ++next_value_number_function;
 
-               set_value(parameter->parameter.v.value_number, value);
+               set_value(parameter->variable.v.value_number, value);
        }
 }