- implemented semantic checks for bitfield

[r21980]

diff --git a/parser.c b/parser.c
index 7aaa859..36e760e 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -134,6 +134,9 @@ static struct obstack      temp_obst;
 
 static source_position_t null_position = { NULL, 0 };
 
+/** special symbol used for anonymous entities. */
+static const symbol_t *sym_anonymous = NULL;
+
 /* symbols for Microsoft extended-decl-modifier */
 static const symbol_t *sym_align      = NULL;
 static const symbol_t *sym_allocate   = NULL;
@@ -5518,15 +5521,39 @@ static void parse_external_declaration(void)
 }
 
 static type_t *make_bitfield_type(type_t *base_type, expression_t *size,
-                                  source_position_t *source_position)
+                                  source_position_t *source_position,
+                                  const symbol_t *symbol)
 {
        type_t *type = allocate_type_zero(TYPE_BITFIELD, source_position);
 
        type->bitfield.base_type       = base_type;
        type->bitfield.size_expression = size;
 
+       il_size_t bit_size;
+       type_t *skipped_type = skip_typeref(base_type);
+       if (!is_type_integer(skipped_type)) {
+               errorf(HERE, "bitfield base type '%T' is not an integer type",
+                       base_type);
+               bit_size = 0;
+       } else {
+               bit_size = skipped_type->base.size * 8;
+       }
+
        if (is_constant_expression(size)) {
-               type->bitfield.bit_size = fold_constant(size);
+               long v = fold_constant(size);
+
+               if (v < 0) {
+                       errorf(source_position, "negative width in bit-field '%Y'",
+                               symbol);
+               } else if (v == 0) {
+                       errorf(source_position, "zero width for bit-field '%Y'",
+                               symbol);
+               } else if (bit_size > 0 && (il_size_t)v > bit_size) {
+                       errorf(source_position, "width of '%Y' exceeds its type",
+                               symbol);
+               } else {
+                       type->bitfield.bit_size = v;
+               }
        }
 
        return type;
@@ -5579,12 +5606,8 @@ static void parse_compound_declarators(declaration_t *struct_declaration,
                        type_t *base_type = specifiers->type;
                        expression_t *size = parse_constant_expression();
 
-                       if (!is_type_integer(skip_typeref(base_type))) {
-                               errorf(HERE, "bitfield base type '%T' is not an integer type",
-                                      base_type);
-                       }
-
-                       type_t *type = make_bitfield_type(base_type, size, &source_position);
+                       type_t *type = make_bitfield_type(base_type, size,
+                                       &source_position, sym_anonymous);
 
                        declaration                         = allocate_declaration_zero();
                        declaration->namespc                = NAMESPACE_NORMAL;
@@ -5604,12 +5627,8 @@ static void parse_compound_declarators(declaration_t *struct_declaration,
                                next_token();
                                expression_t *size = parse_constant_expression();
 
-                               if (!is_type_integer(type)) {
-                                       errorf(HERE, "bitfield base type '%T' is not an integer type",
-                                              orig_type);
-                               }
-
-                               type_t *bitfield_type = make_bitfield_type(orig_type, size, &source_position);
+                               type_t *bitfield_type = make_bitfield_type(orig_type, size,
+                                               &source_position, declaration->symbol);
                                declaration->type = bitfield_type;
                        } else {
                                /* TODO we ignore arrays for now... what is missing is a check
@@ -9830,6 +9849,8 @@ void parse(void)
  */
 void init_parser(void)
 {
+       sym_anonymous = symbol_table_insert("<anonymous>");
+
        if (c_mode & _MS) {
                /* add predefined symbols for extended-decl-modifier */
                sym_align      = symbol_table_insert("align");