Ping
2014-04-16 16:26 GMT+04:00 Ilya Enkovich <enkovich....@gmail.com>:
> Hi,
>
> This patch introduces attributes used by Pointer Bounds Checker. Comparing
> to what was approved for 4.9, this one has additional attribute
> 'bnd_instrument' to be used for selective instrumentation.
>
> Bootstrapped and tested on linux-x86_64.
>
> OK for trunk?
>
> Thanks,
> Ilya
> --
> gcc/
>
> 2014-04-16 Ilya Enkovich <ilya.enkov...@intel.com>
>
> * c-family/c-common.c (handle_bnd_variable_size_attribute): New.
> (handle_bnd_legacy): New.
> (handle_bnd_instrument): New.
> (c_common_attribute_table): Add bnd_variable_size, bnd_legacy
> and bnd_instrument.
> * doc/extend.texi: Document bnd_variable_size, bnd_legacy and
> bnd_instrument attributes.
>
>
> diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
> index 1d56bc0..babf89a 100644
> --- a/gcc/c-family/c-common.c
> +++ b/gcc/c-family/c-common.c
> @@ -379,6 +379,9 @@ static tree handle_omp_declare_simd_attribute (tree *,
> tree, tree, int,
> bool *);
> static tree handle_omp_declare_target_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 tree handle_bnd_instrument (tree *, tree, tree, int, bool *);
>
> static void check_function_nonnull (tree, int, tree *);
> static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
> @@ -772,6 +775,12 @@ const struct attribute_spec c_common_attribute_table[] =
> handle_alloc_align_attribute, false },
> { "assume_aligned", 1, 2, false, true, true,
> handle_assume_aligned_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 },
> + { "bnd_instrument", 0, 0, true, false, false,
> + handle_bnd_instrument, false },
> { NULL, 0, 0, false, false, false, NULL, false }
> };
>
> @@ -8118,6 +8127,54 @@ 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 "bnd_instrument" attribute; arguments as in
> + struct attribute_spec.handler. */
> +
> +static tree
> +handle_bnd_instrument (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 1c74990..3c18829 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -2182,7 +2182,7 @@ attributes are currently defined for functions on all
> targets:
> @code{returns_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{bnd_instrument},
> @code{error} and @code{warning}.
> Several other attributes are defined for functions on particular
> target systems. Other attributes, including @code{section} are
> @@ -3684,6 +3684,18 @@ 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-pointer-bounds} option.
> +
> +@item bnd_instrument
> +@cindex @code{bnd_instrument} function attribute
> +The @code{bnd_instrument} attribute on functions is used to inform
> +compiler that function should be instrumented when compiled
> +with @option{-fchkp-instrument-marked-only} option.
> +
> @item regparm (@var{number})
> @cindex @code{regparm} attribute
> @cindex functions that are passed arguments in registers on the 386
> @@ -5501,12 +5513,12 @@ 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
> @@ -5798,6 +5810,35 @@ 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 Pointer
> +Bounds 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
