Re: [PATCH] Add support for function attributes and variable attributes

[Guillaume Gomez <guillaume1.gomez@gmail.com>]

Hi David,

> The above looks correct, but the patch adds the entrypoint descriptions
> to topics/types.rst, which seems like the wrong place.  The function-
> related ones should be in topics/functions.rst in the "Functions"
> section and the lvalue/variable one in topics/expression.rst after the
> "Global variables" section.

Ah indeed. Mix-up on my end. Fixed it.

> test-restrict.c is a pre-existing testcase, so please don't delete its
> entry.

Ah indeed, I went too quickly and thought it was a test I renamed...

> BTW, the ChangeLog entry mentions adding test-restrict.c, but the patch
> doesn't add it, so that part of the proposed ChangeLog is wrong.
>
> Does the patch pass ./contrib/gcc-changelog/git_check_commit.py ?

I messed up a bit, fixed it thanks to you. I didn't run the script in my last
update but just did:

```
$ contrib/gcc-changelog/git_check_commit.py $(git log -1 --format=%h)
Checking 3849ee2eadf0eeec2b0080a5142ced00be96a60d: OK
```

> Otherwise, looks good, assuming that the patch has been tested with the
> full jit testsuite.

When rebasing on upstream yesterday I discovered that two tests
were not working anymore. For the first one, it was simply because of
the changes in `dummy-frontend.cc`. For the second one
(test-noinline-attribute.c), it was because the rules for inlining changed
since we wrote this patch apparently (our fork is very late). Antoni discovered
that we could just add a call to `asm` to prevent this from happening so I
added it.

So yes, all jit tests are passing as expected. :)

Le jeu. 11 janv. 2024 à 19:46, David Malcolm <dmalcolm@redhat.com> a écrit :
>
> On Thu, 2024-01-11 at 01:00 +0100, Guillaume Gomez wrote:
> > Hi David.
> >
> > Thanks for the review!
> >
> > > > +.. function::  void\
> > > > +               gcc_jit_lvalue_add_string_attribute
> > > > (gcc_jit_lvalue *variable,
> > > > +                                                    enum
> > > > gcc_jit_fn_attribute attribute,
> > >
> > > ^^
> > >
> > > This got out of sync with the declaration in the header file; it
> > > should
> > > be enum gcc_jit_variable_attribute attribute
> >
> > Indeed, good catch!
> >
> > > I took a brief look through the handler functions and with the
> > > above
> > > caveat I didn't see anything obviously wrong.  I'm going to assume
> > > this
> > > code is OK given that presumably you've been testing it within
> > > rustc,
> > > right?
> >
> > Both in rustc and in the JIT tests we added.
> >
> > [..snip...]
> >
> > I added all the missing `RETURN_IF_FAIL` you mentioned. None of the
> > arguments should be `NULL` so it was a mistake not to check it.
> >
> > [..snip...]
> >
> > I removed the tests comments as you mentioned.
> >
> > > Please update jit.dg/all-non-failing-tests.h for the new tests;
> > > it's
> > > meant to list all of the (non failing) tests alphabetically.
> >
> > It's not always correctly sorted. Might be worth sending a patch
> > after this
> > one gets merged to fix that.
> >
> > > I *think* all of the new tests aren't suitable to be run as part of
> > > a
> > > shared context (e.g. due to touching the optimization level or
> > > examining generated asm), so they should be listed in that header
> > > with
> > > comments explaining why.
> >
> > I added them with a comment on top of each of them.
> >
> > I joined the new patch version.
> >
> > Thanks again for the review!
>
> Thanks for the updated patch.  I noticed a few minor issues:
>
> > diff --git a/gcc/jit/docs/topics/types.rst b/gcc/jit/docs/topics/types.rst
> > index bb51f037b7e..b1aedc03787 100644
> > --- a/gcc/jit/docs/topics/types.rst
> > +++ b/gcc/jit/docs/topics/types.rst
> > @@ -553,3 +553,80 @@ Reflection API
> >     .. code-block:: c
> >
> >        #ifdef LIBGCCJIT_HAVE_gcc_jit_type_get_restrict
> > +
> > +.. function::  void\
> > +               gcc_jit_function_add_attribute (gcc_jit_function *func,
> > +                                               enum gcc_jit_fn_attribute attribute)
> > +
> > +     Add an attribute ``attribute`` to a function ``func``.
> > +
> > +     This is equivalent to the following code:
> > +
> > +  .. code-block:: c
> > +
> > +    __attribute__((always_inline))
> > +
> > +   This entrypoint was added in :ref:`LIBGCCJIT_ABI_26`; you can test for
> > +   its presence using
> > +
> > +   .. code-block:: c
> > +
> > +      #ifdef LIBGCCJIT_HAVE_ATTRIBUTES
> > +
> > +.. function::  void\
> > +               gcc_jit_function_add_string_attribute (gcc_jit_function *func,
> > +                                                      enum gcc_jit_fn_attribute attribute,
> > +                                                      const char *value)
> > +
> > +     Add a string attribute ``attribute`` with value ``value`` to a function
> > +     ``func``.
> > +
> > +     This is equivalent to the following code:
> > +
> > +  .. code-block:: c
> > +
> > +    __attribute__ ((alias ("xxx")))
> > +
> > +   This entrypoint was added in :ref:`LIBGCCJIT_ABI_26`; you can test for
> > +   its presence using
> > +
> > +   .. code-block:: c
> > +
> > +      #ifdef LIBGCCJIT_HAVE_ATTRIBUTES
> > +
> > +.. function::  void\
> > +               gcc_jit_function_add_integer_array_attribute (gcc_jit_function *func,
> > +                                                             enum gcc_jit_fn_attribute attribute,
> > +                                                             const int *value,
> > +                                                             size_t length)
> > +
> > +     Add an attribute ``attribute`` with ``length`` integer values ``value`` to a
> > +     function ``func``. The integer values must be the same as you would write
> > +     them in a C code.
> > +
> > +     This is equivalent to the following code:
> > +
> > +  .. code-block:: c
> > +
> > +    __attribute__ ((nonnull (1, 2)))
> > +
> > +   This entrypoint was added in :ref:`LIBGCCJIT_ABI_26`; you can test for
> > +   its presence using
> > +
> > +   .. code-block:: c
> > +
> > +      #ifdef LIBGCCJIT_HAVE_ATTRIBUTES
> > +
> > +.. function::  void\
> > +               gcc_jit_lvalue_add_string_attribute (gcc_jit_lvalue *variable,
> > +                                                    enum gcc_jit_variable_attribute attribute,
> > +                                                    const char *value)
> > +
> > +     Add an attribute ``attribute`` with value ``value`` to a variable ``variable``.
> > +
> > +   This entrypoint was added in :ref:`LIBGCCJIT_ABI_26`; you can test for
> > +   its presence using
> > +
> > +   .. code-block:: c
> > +
> > +      #ifdef LIBGCCJIT_HAVE_ATTRIBUTES
>
> The above looks correct, but the patch adds the entrypoint descriptions
> to topics/types.rst, which seems like the wrong place.  The function-
> related ones should be in topics/functions.rst in the "Functions"
> section and the lvalue/variable one in topics/expression.rst after the
> "Global variables" section.
>
> > diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h
> b/gcc/testsuite/jit.dg/all-non-failing-tests.h
> > index e762563f9bd..84001203352 100644
> > --- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
> > +++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
>
> [...snip...]
>
> > @@ -313,7 +334,7 @@
> >  #undef create_code
> >  #undef verify_code
> >
> > -/* test-restrict.c: This can't be in the testcases array as it needs
> > +/* test-restrict-attribute.c: This can't be in the testcases array as it needs
> >     the `-O3` flag.  */
>
> test-restrict.c is a pre-existing testcase, so please don't delete its
> entry.
> BTW, the ChangeLog entry mentions adding test-restrict.c, but the patch
> doesn't add it, so that part of the proposed ChangeLog is wrong.
>
> Does the patch pass ./contrib/gcc-changelog/git_check_commit.py ?
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-cold-attribute.c b/gcc/testsuite/jit.dg/test-cold-attribute.c
> > new file mode 100644
> > index 00000000000..8dc7ec5a34b
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-cold-attribute.c
> > @@ -0,0 +1,54 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O2 to see that the cold
> > +   attribute affects the optimizations. */
>
> Please delete the above comment.
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +  // Set "-O2".
> > +  gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 2);
> > +}
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-const-attribute.c b/gcc/testsuite/jit.dg/test-const-attribute.c
> > new file mode 100644
> > index 00000000000..c06742d163f
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-const-attribute.c
> > @@ -0,0 +1,134 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O3 to see that the const
> > +   attribute affects the optimizations. */
>
> Please delete the above comment.
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +  // Set "-O3".
> > +  gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 3);
> > +}
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-noinline-attribute.c b/gcc/testsuite/jit.dg/test-noinline-attribute.c
> > new file mode 100644
> > index 00000000000..a455b4493fd
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-noinline-attribute.c
> > @@ -0,0 +1,121 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O2 to see that the `noinline`
> > +   attribute affects the optimizations. */
>
> Please delete the above comment.
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +  // Set "-O2".
> > +  gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 2);
> > +}
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-nonnull-attribute.c b/gcc/testsuite/jit.dg/test-nonnull-attribute.c
> > new file mode 100644
> > index 00000000000..3306f890657
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-nonnull-attribute.c
> > @@ -0,0 +1,94 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O2 to see that the nonnull
> > +   attribute affects the optimizations. */
>
> Please delete the above comment.
>
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +  // Set "-O2".
> > +  gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 2);
> > +}
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-pure-attribute.c b/gcc/testsuite/jit.dg/test-pure-attribute.c
> > new file mode 100644
> > index 00000000000..0c9ba1366e0
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-pure-attribute.c
> > @@ -0,0 +1,134 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O3 to see that the pure
> > +   attribute affects the optimizations. */
>
> Please delete the above comment.
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +  // Set "-O3".
> > +  gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 3);
> > +}
> > +
>
> [...snip...]
>
> > diff --git a/gcc/testsuite/jit.dg/test-restrict-attribute.c b/gcc/testsuite/jit.dg/test-restrict-attribute.c
> > new file mode 100644
> > index 00000000000..7d7444b624f
> > --- /dev/null
> > +++ b/gcc/testsuite/jit.dg/test-restrict-attribute.c
> > @@ -0,0 +1,77 @@
> > +/* { dg-do compile { target x86_64-*-* } } */
> > +
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +
> > +#include "libgccjit.h"
> > +
> > +/* We don't want set_options() in harness.h to set -O3 to see that the restrict
> > +      attribute affects the optimizations. */
>
> Please delete this comment.
>
> > +#define TEST_ESCHEWS_SET_OPTIONS
> > +static void set_options (gcc_jit_context *ctxt, const char *argv0)
> > +{
> > +     // Set "-O3".
> > +     gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 3);
> > +}
> > +
>
> [...snip...]
>
> Otherwise, looks good, assuming that the patch has been tested with the
> full jit testsuite.
>
> Thanks again
> Dave
>