It does not hurt to submit the patch for review -- you need to provide
more background and motivation for this work
1) comparison with -finstrument-functions (runtime overhead etc)
2) use model difference (production binary ..)
3) Interesting examples of use cases (with graphs).
thanks,
David
On Mon, Nov 5, 2012 at 12:20 PM, Harshit Chopra <hars...@google.com> wrote:
> Thanks David for the review. My comments are inline.
>
>
> On Sat, Nov 3, 2012 at 12:38 PM, Xinliang David Li <davi...@google.com> wrote:
>>
>> Harshit, Nov 5 is the gcc48 cutoff date. If you want to have the x-ray
>> instrumentation feature into this release, you will need to port your
>> patch and submit for trunk review now.
>
>
> I am a bit too late now, I guess. If I target for the next release,
> will it create any issues for the gcc48 release?
>
>>
>>
>>
>> On Tue, Oct 30, 2012 at 5:15 PM, Harshit Chopra <hars...@google.com> wrote:
>> > Adding function attributes: 'always_patch_for_instrumentation' and
>> > 'never_patch_for_instrumentation' to always patch a function or to never
>> > patch a function, respectively, when given the option
>> > -mpatch-functions-for-instrumentation. Additionally, the attribute
>> > always_patch_for_instrumentation disables inlining of that function.
>> >
>> > Tested:
>> > Tested by 'crosstool-validate.py --crosstool_ver=16 --testers=crosstool'
>> >
>> > ChangeLog:
>> >
>> > 2012-10-30 Harshit Chopra <hars...@google.com>
>> >
>> > * gcc/c-family/c-common.c
>> > (handle_always_patch_for_instrumentation_attribute): Handle
>> > always_patch_for_instrumentation attribute and turn inlining off for the
>> > function.
>> > (handle_never_patch_for_instrumentation_attribute): Handle
>> > never_patch_for_instrumentation
>> > attribute of a function.
>> > * gcc/config/i386/i386.c (check_should_patch_current_function):
>> > Takes into account
>> > always_patch_for_instrumentation or never_patch_for_instrumentation
>> > attribute when
>> > deciding that a function should be patched.
>> > *
>> > gcc/testsuite/gcc.target/i386/patch-functions-force-no-patching.c: Test
>> > case
>> > to test for never_patch_for_instrumentation attribute.
>> > * gcc/testsuite/gcc.target/i386/patch-functions-force-patching.c:
>> > Test case to
>> > test for always_patch_for_instrumentation attribute.
>> > * gcc/tree.h (struct GTY): Add fields for the two attributes and
>> > macros to access
>> > the fields.
>> > diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
>> > index ab416ff..998645d 100644
>> > --- a/gcc/c-family/c-common.c
>> > +++ b/gcc/c-family/c-common.c
>> > @@ -396,6 +396,13 @@ 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_always_patch_for_instrumentation_attribute (tree *,
>> > tree,
>> > + tree, int,
>> > + bool *);
>>
>> Move bool * to the previous line.
>
>
> If I do that, it goes beyond the 80 char boundary.
>
>>
>>
>> > +static tree handle_never_patch_for_instrumentation_attribute (tree *,
>> > tree,
>> > + tree, int,
>> > + bool *);
>> > +
>>
>> Same here.
>
>
> As above.
>
>>
>>
>> > static void check_function_nonnull (tree, int, tree *);
>> > static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
>> > static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
>> > @@ -804,6 +811,13 @@ 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 },
>> > + { "always_patch_for_instrumentation", 0, 0, true, false, false,
>> > +
>> > handle_always_patch_for_instrumentation_attribute,
>> > + false },
>> > + { "never_patch_for_instrumentation", 0, 0, true, false, false,
>> > +
>> > handle_never_patch_for_instrumentation_attribute,
>> > + false },
>> > +
>> > { NULL, 0, 0, false, false, false, NULL, false }
>> > };
>> >
>> > @@ -9158,6 +9172,48 @@ handle_no_thread_safety_analysis_attribute (tree
>> > *node, tree name,
>> > return NULL_TREE;
>> > }
>> >
>> > +/* Handle a "always_patch_for_instrumentation" attribute; arguments as in
>> > + struct attribute_spec.handler. */
>>
>> Add new line here
>
>
> Done.
>
>>
>>
>> > +static tree
>> > +handle_always_patch_for_instrumentation_attribute (tree *node, tree name,
>> > + tree ARG_UNUSED (args),
>> > + int ARG_UNUSED (flags),
>> > + bool *no_add_attrs)
>> > +{
>> > + if (TREE_CODE (*node) == FUNCTION_DECL)
>> > + {
>> > + DECL_FORCE_PATCHING_FOR_INSTRUMENTATION (*node) = 1;
>> > + DECL_UNINLINABLE (*node) = 1;
>> > + }
>> > + else
>> > + {
>> > + warning (OPT_Wattributes, "%qE attribute ignored", name);
>> > + *no_add_attrs = true;
>> > + }
>> > + return NULL_TREE;
>> > +}
>> > +
>> > +
>> > +/* Handle a "never_patch_for_instrumentation" attribute; arguments as in
>> > + struct attribute_spec.handler. */
>>
>> A new line here.
>
>
> Done
>
>>
>>
>> > +static tree
>> > +handle_never_patch_for_instrumentation_attribute (tree *node, tree name,
>> > + tree ARG_UNUSED (args),
>> > + int ARG_UNUSED (flags),
>> > + bool *no_add_attrs)
>> > +{
>> > + if (TREE_CODE (*node) == FUNCTION_DECL)
>> > + DECL_FORCE_NO_PATCHING_FOR_INSTRUMENTATION (*node) = 1;
>>
>> Probably no need for this. The attribute will be attached to the decl
>> node -- can be queried using lookup_attribute method.
>
>
> Done.
>
>>
>>
>> > + else
>> > + {
>> > + warning (OPT_Wattributes, "%qE attribute ignored", name);
>> > + *no_add_attrs = true;
>> > + }
>> > + return NULL_TREE;
>> > +}
>> > +
>> > +
>> > +
>> > /* Check for valid arguments being passed to a function with FNTYPE.
>> > There are NARGS arguments in the array ARGARRAY. */
>> > void
>> > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> > index 6972ae6..b1475bf 100644
>> > --- a/gcc/config/i386/i386.c
>> > +++ b/gcc/config/i386/i386.c
>> > @@ -10983,6 +10983,13 @@ check_should_patch_current_function (void)
>> > int num_loops = 0;
>> > int min_functions_instructions;
>> >
>> > + /* If a function has an attribute forcing patching on or off, do as it
>> > + indicates. */
>> > + if (DECL_FORCE_PATCHING_FOR_INSTRUMENTATION (current_function_decl))
>> > + return true;
>> > + else if (DECL_FORCE_NO_PATCHING_FOR_INSTRUMENTATION
>> > (current_function_decl))
>> > + return false;
>> > +
>> > /* Patch the function if it has at least a loop. */
>> > if (!patch_functions_ignore_loops)
>> > {
>> > diff --git
>> > a/gcc/testsuite/gcc.target/i386/patch-functions-force-no-patching.c
>> > b/gcc/testsuite/gcc.target/i386/patch-functions-force-no-patching.c
>> > new file mode 100644
>> > index 0000000..cad6f2d
>> > --- /dev/null
>> > +++ b/gcc/testsuite/gcc.target/i386/patch-functions-force-no-patching.c
>> > @@ -0,0 +1,27 @@
>> > +/* { dg-do compile } */
>> > +/* { dg-require-effective-target lp64 } */
>> > +/* { dg-options "-mpatch-functions-for-instrumentation
>> > -mno-patch-functions-main-always" } */
>>
>> > /* Nonzero if a FUNCTION_CODE is a TM load/store. */
>> > #define BUILTIN_TM_LOAD_STORE_P(FN) \
>> > ((FN) >= BUILT_IN_TM_STORE_1 && (FN) <= BUILT_IN_TM_LOAD_RFW_LDOUBLE)
>> > @@ -3586,7 +3596,8 @@ struct GTY(()) tree_function_decl {
>> > unsigned has_debug_args_flag : 1;
>> > unsigned tm_clone_flag : 1;
>> >
>> > - /* 1 bit left */
>> > + unsigned force_patching_for_instrumentation : 1;
>> > + unsigned force_no_patching_for_instrumentation : 1;
>>
>>
>> I don't think you should use precious bits here -- directly query the
>> attributes.
>
>
> Done.
>
>>
>>
>> thanks,
>>
>> David
>>
>> > };
>> >
>> > /* The source language of the translation-unit. */
>> >
>> > --
>> > This patch is available for review at http://codereview.appspot.com/6821051
