Hi,
This patch adds attributes 'bnd_variable_size' and 'bnd_legacy' used by
Pointers Checker.
Bootstrapped and tested on linux-x86_64.
Thanks,
Ilya
--
gcc/
2013-10-21 Ilya Enkovich <ilya.enkov...@intel.com>
* c-family/c-common.c (handle_bnd_variable_size_attribute): New.
(handle_bnd_legacy): New.
(c_common_attribute_table): Add bnd_variable_size and bnd_legacy.
* doc/extend.texi: Document bnd_variable_size and bnd_legacy
attributes.
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 8ecb70c..3902909 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -371,6 +371,8 @@ static tree ignore_attribute (tree *, tree, tree, int, bool
*);
static tree handle_no_split_stack_attribute (tree *, tree, tree, int, bool *);
static tree handle_fnspec_attribute (tree *, tree, tree, int, bool *);
static tree handle_warn_unused_attribute (tree *, tree, tree, int, bool *);
+static tree handle_bnd_variable_size_attribute (tree *, tree, tree, int, bool
*);
+static tree handle_bnd_legacy (tree *, tree, tree, int, bool *);
static void check_function_nonnull (tree, int, tree *);
static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
@@ -745,8 +747,12 @@ const struct attribute_spec c_common_attribute_table[] =
The name contains space to prevent its usage in source code. */
{ "fn spec", 1, 1, false, true, true,
handle_fnspec_attribute, false },
- { "warn_unused", 0, 0, false, false, false,
+ { "warn_unused", 0, 0, false, false, false,
handle_warn_unused_attribute, false },
+ { "bnd_variable_size", 0, 0, true, false, false,
+ handle_bnd_variable_size_attribute, false },
+ { "bnd_legacy", 0, 0, true, false, false,
+ handle_bnd_legacy, false },
{ NULL, 0, 0, false, false, false, NULL, false }
};
@@ -8000,6 +8006,38 @@ handle_fnspec_attribute (tree *node ATTRIBUTE_UNUSED,
tree ARG_UNUSED (name),
return NULL_TREE;
}
+/* Handle a "bnd_variable_size" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+handle_bnd_variable_size_attribute (tree *node, tree name, tree ARG_UNUSED
(args),
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ if (TREE_CODE (*node) != FIELD_DECL)
+ {
+ warning (OPT_Wattributes, "%qE attribute ignored", name);
+ *no_add_attrs = true;
+ }
+
+ return NULL_TREE;
+}
+
+/* Handle a "bnd_legacy" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+handle_bnd_legacy (tree *node, tree name, tree ARG_UNUSED (args),
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ if (TREE_CODE (*node) != FUNCTION_DECL)
+ {
+ warning (OPT_Wattributes, "%qE attribute ignored", name);
+ *no_add_attrs = true;
+ }
+
+ return NULL_TREE;
+}
+
/* Handle a "warn_unused" attribute; arguments as in
struct attribute_spec.handler. */
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index ef422ad..7701d60 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -2137,7 +2137,7 @@ attributes are currently defined for functions on all
targets:
@code{warn_unused_result}, @code{nonnull}, @code{gnu_inline},
@code{externally_visible}, @code{hot}, @code{cold}, @code{artificial},
@code{no_sanitize_address}, @code{no_address_safety_analysis},
-@code{no_sanitize_undefined},
+@code{no_sanitize_undefined}, @code{bnd_legacy},
@code{error} and @code{warning}.
Several other attributes are defined for functions on particular
target systems. Other attributes, including @code{section} are
@@ -3508,6 +3508,12 @@ The @code{no_sanitize_undefined} attribute on functions
is used
to inform the compiler that it should not check for undefined behavior
in the function when compiling with the @option{-fsanitize=undefined} option.
+@item bnd_legacy
+@cindex @code{bnd_legacy} function attribute
+The @code{bnd_legacy} attribute on functions is used to inform
+compiler that function should not be instrumented when compiled
+with @option{-fcheck-pointers} option.
+
@item regparm (@var{number})
@cindex @code{regparm} attribute
@cindex functions that are passed arguments in registers on the 386
@@ -5280,12 +5286,12 @@ placed in either the @code{.bss_below100} section or the
The keyword @code{__attribute__} allows you to specify special
attributes of @code{struct} and @code{union} types when you define
such types. This keyword is followed by an attribute specification
-inside double parentheses. Seven attributes are currently defined for
+inside double parentheses. Eight attributes are currently defined for
types: @code{aligned}, @code{packed}, @code{transparent_union},
-@code{unused}, @code{deprecated}, @code{visibility}, and
-@code{may_alias}. Other attributes are defined for functions
-(@pxref{Function Attributes}) and for variables (@pxref{Variable
-Attributes}).
+@code{unused}, @code{deprecated}, @code{visibility}, @code{may_alias}
+and @code{bnd_variable_size}. Other attributes are defined for
+functions (@pxref{Function Attributes}) and for variables
+(@pxref{Variable Attributes}).
You may also specify any one of these attributes with @samp{__}
preceding and following its keyword. This allows you to use these
@@ -5577,6 +5583,35 @@ and caught in another, the class must have default
visibility.
Otherwise the two shared objects are unable to use the same
typeinfo node and exception handling will break.
+@item bnd_variable_size
+When applied to a structure field, this attribute tells Pointers
+Checker that the size of this field should not be computed using
+static type information. It may be used to mark variable sized
+static array fields placed at the end of a structure.
+
+@smallexample
+struct S
+@{
+ int size;
+ char data[1];
+@}
+S *p = (S *)malloc (sizeof(S) + 100);
+p->data[10] = 0; //Bounds violation
+@end smallexample
+
+By using an attribute for a field we may avoid bound violation
+we most probably do not want to see:
+
+@smallexample
+struct S
+@{
+ int size;
+ char data[1] __attribute__((bnd_variable_size));
+@}
+S *p = (S *)malloc (sizeof(S) + 100);
+p->data[10] = 0; //OK
+@end smallexample
+
@end table
To specify multiple attributes, separate them by commas within the
