On Wednesday, September 02, 2015 02:35:22 PM Ilia Mirkin wrote:
> On Wed, Sep 2, 2015 at 2:20 PM, Kenneth Graunke <kenn...@whitecape.org> wrote:
> > In various versions of OpenGL and GLSL, it's possible to declare
> > multiple VS input variables with aliasing attribute locations.
> >
> > So, when computing the storage requirements for vertex attributes,
> > we can't simply add up the sizes. Instead, we need to look at the
> > enabled slots.
> >
> > This patch begins tracking which attributes are double types that
> > are larger than 128-bits (i.e. take up two vec4 slots). We then
> > count normal attributes once, and count the double-size attributes
> > a second time.
> >
> > Fixes deQP functional.attribute_location.bind_aliasing.max_cond_* tests
> > on i965, which regressed with commit ad208d975a6d3aebe14f7c2c16039ee20.
>
> This is all subtle stuff. I'd feel a whole lot better if there were
> some piglit coverage for this.
>
> >
> > Cc: "10.6 11.0" <mesa-sta...@lists.freedesktop.org>
> > Cc: Matt Turner <matts...@gmail.com.
> > Cc: Ilia Mirkin <imir...@alum.mit.edu>
> > Cc: Dave Airlie <airl...@gmail.com>
> > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
> > ---
> > src/glsl/linker.cpp | 64
> > ++++++++++++++++++++++++++++++-----------------------
> > 1 file changed, 36 insertions(+), 28 deletions(-)
> >
> > diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> > index 47f7d25..934062f 100644
> > --- a/src/glsl/linker.cpp
> > +++ b/src/glsl/linker.cpp
> > @@ -2339,6 +2339,7 @@ assign_attribute_or_color_locations(gl_shader_program
> > *prog,
> > */
> > unsigned used_locations = (max_index >= 32)
> > ? ~0 : ~((1 << max_index) - 1);
> > + unsigned double_storage_locations = 0;
> >
> > assert((target_index == MESA_SHADER_VERTEX)
> > || (target_index == MESA_SHADER_FRAGMENT));
> > @@ -2452,34 +2453,6 @@
> > assign_attribute_or_color_locations(gl_shader_program *prog,
> >
> > const unsigned slots = var->type->count_attribute_slots();
> >
> > - /* From GL4.5 core spec, section 11.1.1 (Vertex Attributes):
> > - *
> > - * "A program with more than the value of MAX_VERTEX_ATTRIBS active
> > - * attribute variables may fail to link, unless device-dependent
> > - * optimizations are able to make the program fit within available
> > - * hardware resources. For the purposes of this test, attribute
> > variables
> > - * of the type dvec3, dvec4, dmat2x3, dmat2x4, dmat3, dmat3x4,
> > dmat4x3,
> > - * and dmat4 may count as consuming twice as many attributes as
> > equivalent
> > - * single-precision types. While these types use the same number of
> > - * generic attributes as their single-precision equivalents,
> > - * implementations are permitted to consume two single-precision
> > vectors
> > - * of internal storage for each three- or four-component
> > double-precision
> > - * vector."
> > - * Until someone has a good reason in Mesa, enforce that now.
> > - */
> > - if (target_index == MESA_SHADER_VERTEX) {
> > - total_attribs_size += slots;
> > - if (var->type->without_array() == glsl_type::dvec3_type ||
> > - var->type->without_array() == glsl_type::dvec4_type ||
> > - var->type->without_array() == glsl_type::dmat2x3_type ||
> > - var->type->without_array() == glsl_type::dmat2x4_type ||
> > - var->type->without_array() == glsl_type::dmat3_type ||
> > - var->type->without_array() == glsl_type::dmat3x4_type ||
> > - var->type->without_array() == glsl_type::dmat4x3_type ||
> > - var->type->without_array() == glsl_type::dmat4_type)
> > - total_attribs_size += slots;
> > - }
> > -
> > /* If the variable is not a built-in and has a location statically
> > * assigned in the shader (presumably via a layout qualifier), make
> > sure
> > * that it doesn't collide with other assigned locations. Otherwise,
> > @@ -2594,6 +2567,38 @@
> > assign_attribute_or_color_locations(gl_shader_program *prog,
> > }
> >
> > used_locations |= (use_mask << attr);
> > +
> > + /* From the GL 4.5 core spec, section 11.1.1 (Vertex
> > Attributes):
> > + *
> > + * "A program with more than the value of MAX_VERTEX_ATTRIBS
> > + * active attribute variables may fail to link, unless
> > + * device-dependent optimizations are able to make the program
> > + * fit within available hardware resources. For the purposes
> > + * of this test, attribute variables of the type dvec3, dvec4,
> > + * dmat2x3, dmat2x4, dmat3, dmat3x4, dmat4x3, and dmat4 may
> > + * count as consuming twice as many attributes as equivalent
> > + * single-precision types. While these types use the same
> > number
> > + * of generic attributes as their single-precision
> > equivalents,
> > + * implementations are permitted to consume two
> > single-precision
> > + * vectors of internal storage for each three- or
> > four-component
> > + * double-precision vector."
> > + *
> > + * Mark this attribute slot as taking up twice as much space
> > + * so we can count it properly against limits. According to
> > + * issue (3) of the GL_ARB_vertex_attrib_64bit behavior, this
> > + * is optional behavior, but it seems preferable.
> > + */
> > + const glsl_type *type = var->type->without_array();
> > + if (type == glsl_type::dvec3_type ||
> > + type == glsl_type::dvec4_type ||
> > + type == glsl_type::dmat2x3_type ||
> > + type == glsl_type::dmat2x4_type ||
> > + type == glsl_type::dmat3_type ||
> > + type == glsl_type::dmat3x4_type ||
> > + type == glsl_type::dmat4x3_type ||
> > + type == glsl_type::dmat4_type) {
> > + double_storage_locations |= (use_mask << attr);
> > + }
> > }
> >
> > continue;
> > @@ -2605,6 +2610,9 @@ assign_attribute_or_color_locations(gl_shader_program
> > *prog,
> > }
> >
> > if (target_index == MESA_SHADER_VERTEX) {
> > + unsigned total_attribs_size =
> > + _mesa_bitcount(used_locations & ((1 << max_index) - 1)) +
> > + _mesa_bitcount(double_storage_locations);
>
> Does this also need the & ((1 << max_index) - 1) treatment? [Well, not
> _need_ but seems like it'd avoid needlessly counting things?]
Should be fine. The masking off here is actually to undo the earlier
code:
/* Mark invalid locations as being used.
*/
unsigned used_locations = (max_index >= 32)
? ~0 : ~((1 << max_index) - 1);
i.e. we only want to count real attributes. I initialized my new
bitfield to 0, so we only ever counted real attributes in the first
place.
I thought about initializing them both to 0 and adding in invalid
locations after this check, but this was less invasive, and so
required less confidence in what I was doing :)
> > if (total_attribs_size > max_index) {
> > linker_error(prog,
> > "attempt to use %d vertex attribute slots only %d
> > available ",
> > --
> > 2.5.0
> >
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