Use an enum to represent subclasses of symbol

This changes struct symbol to use an enum to encode the concrete
subclass of a particular symbol.  Note that "enum class" doesn't work
properly with bitfields, so a plain enum is used.

2017-11-17  Tom Tromey  <tom@tromey.com>

	* symtab.h (enum symbol_subclass_kind): New.
	(struct symbol) <is_cplus_template_function, is_rust_vtable>:
	Remove.
	<subclass>: New member.
	(SYMBOL_IS_CPLUS_TEMPLATE_FUNCTION): Update.
	* rust-lang.c (rust_get_trait_object_pointer): Update.
	* dwarf2read.c (read_func_scope): Update.
	(read_variable): Update.
This commit is contained in:
Tom Tromey 2017-11-17 12:05:58 -07:00
parent 68e745e38e
commit cf724bc93e
4 changed files with 32 additions and 11 deletions

View File

@ -1,3 +1,14 @@
2017-11-17 Tom Tromey <tom@tromey.com>
* symtab.h (enum symbol_subclass_kind): New.
(struct symbol) <is_cplus_template_function, is_rust_vtable>:
Remove.
<subclass>: New member.
(SYMBOL_IS_CPLUS_TEMPLATE_FUNCTION): Update.
* rust-lang.c (rust_get_trait_object_pointer): Update.
* dwarf2read.c (read_func_scope): Update.
(read_variable): Update.
2017-11-17 Tom Tromey <tom@tromey.com>
* dwarf2read.c (read_func_scope): Update.

View File

@ -12263,7 +12263,7 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
|| child_die->tag == DW_TAG_template_value_param)
{
templ_func = allocate_template_symbol (objfile);
templ_func->is_cplus_template_function = 1;
templ_func->subclass = SYMBOL_TEMPLATE;
break;
}
}
@ -12821,7 +12821,7 @@ read_variable (struct die_info *die, struct dwarf2_cu *cu)
struct rust_vtable_symbol);
initialize_objfile_symbol (storage);
storage->concrete_type = containing_type;
storage->is_rust_vtable = 1;
storage->subclass = SYMBOL_RUST_VTABLE;
}
}

View File

@ -421,7 +421,7 @@ rust_get_trait_object_pointer (struct value *value)
CORE_ADDR vtable = value_as_address (value_field (value, vtable_field));
struct symbol *symbol = find_symbol_at_address (vtable);
if (symbol == NULL || !symbol->is_rust_vtable)
if (symbol == NULL || symbol->subclass != SYMBOL_RUST_VTABLE)
return NULL;
struct rust_vtable_symbol *vtable_sym

View File

@ -1009,6 +1009,21 @@ struct symbol_impl
const struct symbol_register_ops *ops_register;
};
/* struct symbol has some subclasses. This enum is used to
differentiate between them. */
enum symbol_subclass_kind
{
/* Plain struct symbol. */
SYMBOL_NONE,
/* struct template_symbol. */
SYMBOL_TEMPLATE,
/* struct rust_vtable_symbol. */
SYMBOL_RUST_VTABLE
};
/* This structure is space critical. See space comments at the top. */
struct symbol
@ -1058,14 +1073,9 @@ struct symbol
/* Whether this is an inlined function (class LOC_BLOCK only). */
unsigned is_inlined : 1;
/* True if this is a C++ function symbol with template arguments.
In this case the symbol is really a "struct template_symbol". */
unsigned is_cplus_template_function : 1;
/* The concrete type of this symbol. */
/* True if this is a Rust virtual table. In this case, the symbol
can be downcast to "struct rust_vtable_symbol". */
unsigned is_rust_vtable : 1;
ENUM_BITFIELD (symbol_subclass_kind) subclass : 2;
/* Line number of this symbol's definition, except for inlined
functions. For an inlined function (class LOC_BLOCK and
@ -1127,7 +1137,7 @@ extern const struct block_symbol null_block_symbol;
#define SYMBOL_IS_ARGUMENT(symbol) (symbol)->is_argument
#define SYMBOL_INLINED(symbol) (symbol)->is_inlined
#define SYMBOL_IS_CPLUS_TEMPLATE_FUNCTION(symbol) \
(symbol)->is_cplus_template_function
(((symbol)->subclass) == SYMBOL_TEMPLATE)
#define SYMBOL_TYPE(symbol) (symbol)->type
#define SYMBOL_LINE(symbol) (symbol)->line
#define SYMBOL_COMPUTED_OPS(symbol) (SYMBOL_IMPL (symbol).ops_computed)