[Mesa-dev] [PATCH 05/15] i965/fs: Stop relying on param_size in assign_constant_locations

[Jason Ekstrand]

On Dec 10, 2015 9:06 AM, "Francisco Jerez" <currojerez at riseup.net> wrote:
>
> Michael Schellenberger Costa <mschellenbergercosta at googlemail.com>
> writes:
>
> > Hi,
> >
> > Am 10.12.2015 um 05:23 schrieb Jason Ekstrand:
> >> Now that we have MOV_INDIRECT opcodes, we have all of the size
information
> >> we need directly in the opcode.  With a little restructuring of the
> >> algorithm used in assign_constant_locations we don't need param_size
> >> anymore.  The big thing to watch out for now, however, is that you can
have
> >> two ranges overlap where neither contains the other.  In order to deal
with
> >> this, we make the first pass just flag what needs pulling and handle
> >> assigning pull constant locations until later.
> >> ---
> >>  src/mesa/drivers/dri/i965/brw_fs.cpp | 44
++++++++++++++----------------------
> >>  1 file changed, 17 insertions(+), 27 deletions(-)
> >>
> >> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> index 786c5fb..1add656 100644
> >> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> @@ -1920,14 +1920,12 @@ fs_visitor::assign_constant_locations()
> >>     if (dispatch_width != 8)
> >>        return;
> >>
> >> -   unsigned int num_pull_constants = 0;
> >> -
> >> -   pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
> >> -   memset(pull_constant_loc, -1, sizeof(pull_constant_loc[0]) *
uniforms);
> >> -
> >>     bool is_live[uniforms];
> >>     memset(is_live, 0, sizeof(is_live));
> >>
> >> +   bool needs_pull[uniforms];
> >> +   memset(needs_pull, 0, sizeof(is_live));
> > While it is valid, could you make this sizeof(needs_pull) to be safe?
> > Michael
>
> This is why the language provides a type-safe way to initialize a
> variable.  Empty aggregate initializer please?

What's the syntax for that in C++?  Does this work?

book needs_pull[uniforms] = { false };

> >
> >> +
> >>     /* First, we walk through the instructions and do two things:
> >>      *
> >>      *  1) Figure out which uniforms are live.
> >> @@ -1943,20 +1941,15 @@ fs_visitor::assign_constant_locations()
> >>           if (inst->src[i].file != UNIFORM)
> >>              continue;
> >>
> >> -         if (inst->opcode == SHADER_OPCODE_MOV_INDIRECT && i == 0) {
> >> -            int uniform = inst->src[0].nr;
> >> +         int constant_nr = inst->src[i].nr + inst->src[i].reg_offset;
> >>
> >> -            /* If this array isn't already present in the pull
constant buffer,
> >> -             * add it.
> >> -             */
> >> -            if (pull_constant_loc[uniform] == -1) {
> >> -               assert(param_size[uniform]);
> >> -               for (int j = 0; j < param_size[uniform]; j++)
> >> -                  pull_constant_loc[uniform + j] =
num_pull_constants++;
> >> +         if (inst->opcode == SHADER_OPCODE_MOV_INDIRECT && i == 0) {
> >> +            for (unsigned j = 0; j < inst->src[2].ud / 4; j++) {
> >> +               is_live[constant_nr + j] = true;
> >> +               needs_pull[constant_nr + j] = true;
> >>              }
> >>           } else {
> >>              /* Mark the the one accessed uniform as live */
> >> -            int constant_nr = inst->src[i].nr +
inst->src[i].reg_offset;
> >>              if (constant_nr >= 0 && constant_nr < (int) uniforms)
> >>                 is_live[constant_nr] = true;
> >>           }
> >> @@ -1973,26 +1966,23 @@ fs_visitor::assign_constant_locations()
> >>      */
> >>     unsigned int max_push_components = 16 * 8;
> >>     unsigned int num_push_constants = 0;
> >> +   unsigned int num_pull_constants = 0;
> >>
> >>     push_constant_loc = ralloc_array(mem_ctx, int, uniforms);
> >> +   pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
> >>
> >>     for (unsigned int i = 0; i < uniforms; i++) {
> >> -      if (!is_live[i] || pull_constant_loc[i] != -1) {
> >> -         /* This UNIFORM register is either dead, or has already been
demoted
> >> -          * to a pull const.  Mark it as no longer living in the
param[] array.
> >> -          */
> >> -         push_constant_loc[i] = -1;
> >> +      push_constant_loc[i] = -1;
> >> +      pull_constant_loc[i] = -1;
> >> +
> >> +      if (!is_live[i])
> >>           continue;
> >> -      }
> >>
> >> -      if (num_push_constants < max_push_components) {
> >> -         /* Retain as a push constant.  Record the location in the
params[]
> >> -          * array.
> >> -          */
> >> +      if (!needs_pull[i] && num_push_constants < max_push_components)
{
> >> +         /* Retain as a push constant */
> >>           push_constant_loc[i] = num_push_constants++;
> >>        } else {
> >> -         /* Demote to a pull constant. */
> >> -         push_constant_loc[i] = -1;
> >> +         /* We have to pull it */
> >>           pull_constant_loc[i] = num_pull_constants++;
> >>        }
> >>     }
> >>
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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