[Mesa-dev] [PATCH 21/28] i965/blorp: Add initial support for NIR-based blit shaders

Pohjolainen, Topi topi.pohjolainen at intel.com
Fri May 13 05:04:02 UTC 2016


On Tue, May 10, 2016 at 04:16:41PM -0700, Jason Ekstrand wrote:
> Many of the more complex cases still fall back to the old shader builder.
> ---
>  src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 425 +++++++++++++++++++++++++--
>  1 file changed, 401 insertions(+), 24 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> index ea64b11..f94dd6f 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> @@ -25,6 +25,8 @@
>  #include "main/teximage.h"
>  #include "main/fbobject.h"
>  
> +#include "compiler/nir/nir_builder.h"
> +
>  #include "intel_fbo.h"
>  
>  #include "brw_blorp.h"
> @@ -332,6 +334,226 @@ enum sampler_message_arg
>     SAMPLER_MESSAGE_ARG_ZERO_INT,
>  };
>  
> +struct brw_blorp_blit_vars {
> +   /* Uniforms values from brw_blorp_wm_push_constants */
> +   nir_variable *u_dst_x0;
> +   nir_variable *u_dst_x1;
> +   nir_variable *u_dst_y0;
> +   nir_variable *u_dst_y1;
> +   nir_variable *u_rect_grid_x1;
> +   nir_variable *u_rect_grid_y1;
> +   struct {
> +      nir_variable *multiplier;
> +      nir_variable *offset;
> +   } u_x_transform, u_y_transform;
> +   nir_variable *u_src_z;
> +
> +   /* gl_FragCoord */
> +   nir_variable *frag_coord;
> +
> +   /* gl_FragColor */
> +   nir_variable *color_out;
> +};
> +
> +static void
> +brw_blorp_blit_vars_init(nir_builder *b, struct brw_blorp_blit_vars *v,
> +                         const struct brw_blorp_blit_prog_key *key)
> +{
> +#define LOAD_UNIFORM(name, type)\
> +   v->u_##name = nir_variable_create(b->shader, nir_var_uniform, type, #name); \
> +   v->u_##name->data.location = \
> +      offsetof(struct brw_blorp_wm_push_constants, name);
> +
> +   LOAD_UNIFORM(dst_x0, glsl_uint_type())
> +   LOAD_UNIFORM(dst_x1, glsl_uint_type())
> +   LOAD_UNIFORM(dst_y0, glsl_uint_type())
> +   LOAD_UNIFORM(dst_y1, glsl_uint_type())
> +   LOAD_UNIFORM(rect_grid_x1, glsl_float_type())
> +   LOAD_UNIFORM(rect_grid_y1, glsl_float_type())
> +   LOAD_UNIFORM(x_transform.multiplier, glsl_float_type())
> +   LOAD_UNIFORM(x_transform.offset, glsl_float_type())
> +   LOAD_UNIFORM(y_transform.multiplier, glsl_float_type())
> +   LOAD_UNIFORM(y_transform.offset, glsl_float_type())
> +   LOAD_UNIFORM(src_z, glsl_uint_type())
> +
> +#undef DECL_UNIFORM
> +
> +   v->frag_coord = nir_variable_create(b->shader, nir_var_shader_in,
> +                                       glsl_vec4_type(), "gl_FragCoord");
> +   v->frag_coord->data.location = VARYING_SLOT_POS;
> +   v->frag_coord->data.origin_upper_left = true;
> +
> +   v->color_out = nir_variable_create(b->shader, nir_var_shader_out,
> +                                      glsl_vec4_type(), "gl_FragColor");
> +   v->color_out->data.location = FRAG_RESULT_COLOR;
> +}
> +
> +nir_ssa_def *
> +blorp_blit_get_frag_coords(nir_builder *b,
> +                           const struct brw_blorp_blit_prog_key *key,
> +                           struct brw_blorp_blit_vars *v)
> +{
> +   nir_ssa_def *coord = nir_f2i(b, nir_load_var(b, v->frag_coord));
> +
> +   if (key->persample_msaa_dispatch) {
> +      return nir_vec3(b, nir_channel(b, coord, 0), nir_channel(b, coord, 1),
> +         nir_load_system_value(b, nir_intrinsic_load_sample_id, 0));
> +   } else {
> +      return nir_vec2(b, nir_channel(b, coord, 0), nir_channel(b, coord, 1));
> +   }
> +}
> +

We could keep the original comment here:

/**
 * Emit code to translate from destination (X, Y) coordinates to source (X, Y)
 * coordinates.
 */

Otherwise this looks really nice, readability alone is improved a lot. There
is no question that the original was written as clearly as it can be but now
we are able to leave some many details into the generic compiler backend.

> +nir_ssa_def *
> +blorp_blit_apply_transform(nir_builder *b, nir_ssa_def *src_pos,
> +                           struct brw_blorp_blit_vars *v)
> +{
> +   nir_ssa_def *offset = nir_vec2(b, nir_load_var(b, v->u_x_transform.offset),
> +                                     nir_load_var(b, v->u_y_transform.offset));
> +   nir_ssa_def *mul = nir_vec2(b, nir_load_var(b, v->u_x_transform.multiplier),
> +                                  nir_load_var(b, v->u_y_transform.multiplier));
> +
> +   nir_ssa_def *pos = nir_ffma(b, src_pos, mul, offset);
> +
> +   if (src_pos->num_components == 3) {
> +      /* Leave the sample id alone */
> +      pos = nir_vec3(b, nir_channel(b, pos, 0), nir_channel(b, pos, 1),
> +                        nir_channel(b, src_pos, 2));
> +   }
> +
> +   return pos;
> +}
> +
> +static nir_tex_instr *
> +blorp_create_nir_tex_instr(nir_shader *shader, nir_texop op,
> +                           nir_ssa_def *pos, unsigned num_srcs,
> +                           enum brw_reg_type dst_type)
> +{
> +   nir_tex_instr *tex = nir_tex_instr_create(shader, num_srcs);
> +
> +   tex->op = op;
> +
> +   switch (dst_type) {
> +   case BRW_REGISTER_TYPE_F:
> +      tex->dest_type = nir_type_float;
> +      break;
> +   case BRW_REGISTER_TYPE_D:
> +      tex->dest_type = nir_type_int;
> +      break;
> +   case BRW_REGISTER_TYPE_UD:
> +      tex->dest_type = nir_type_uint;
> +      break;
> +   default:
> +      unreachable("Invalid texture return type");
> +   }
> +
> +   tex->is_array = false;
> +   tex->is_shadow = false;
> +
> +   /* Blorp only has one texture and it's bound at unit 0 */
> +   tex->texture = NULL;
> +   tex->sampler = NULL;
> +   tex->texture_index = 0;
> +   tex->sampler_index = 0;
> +
> +   nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
> +
> +   return tex;
> +}
> +
> +static nir_ssa_def *
> +blorp_nir_tex(nir_builder *b, nir_ssa_def *pos, enum brw_reg_type dst_type)
> +{
> +   nir_tex_instr *tex =
> +      blorp_create_nir_tex_instr(b->shader, nir_texop_tex, pos, 2, dst_type);
> +
> +   assert(pos->num_components == 2);
> +   tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
> +   tex->coord_components = 2;
> +   tex->src[0].src_type = nir_tex_src_coord;
> +   tex->src[0].src = nir_src_for_ssa(pos);
> +   tex->src[1].src_type = nir_tex_src_lod;
> +   tex->src[1].src = nir_src_for_ssa(nir_imm_int(b, 0));
> +
> +   nir_builder_instr_insert(b, &tex->instr);
> +
> +   return &tex->dest.ssa;
> +}
> +
> +static nir_ssa_def *
> +blorp_nir_txf(nir_builder *b, struct brw_blorp_blit_vars *v,
> +              nir_ssa_def *pos, enum brw_reg_type dst_type)
> +{
> +   nir_tex_instr *tex =
> +      blorp_create_nir_tex_instr(b->shader, nir_texop_txf, pos, 2, dst_type);
> +
> +   /* In order to properly handle 3-D textures, we pull the Z component from
> +    * a uniform.  TODO: This is a bit magic; we should probably make this
> +    * more explicit in the future.
> +    */
> +   assert(pos->num_components == 2);
> +   pos = nir_vec3(b, nir_channel(b, pos, 0), nir_channel(b, pos, 1),
> +                     nir_load_var(b, v->u_src_z));
> +
> +   tex->sampler_dim = GLSL_SAMPLER_DIM_3D;
> +   tex->coord_components = 3;
> +   tex->src[0].src_type = nir_tex_src_coord;
> +   tex->src[0].src = nir_src_for_ssa(pos);
> +   tex->src[1].src_type = nir_tex_src_lod;
> +   tex->src[1].src = nir_src_for_ssa(nir_imm_int(b, 0));
> +
> +   nir_builder_instr_insert(b, &tex->instr);
> +
> +   return &tex->dest.ssa;
> +}
> +
> +static nir_ssa_def *
> +blorp_nir_txf_ms(nir_builder *b, nir_ssa_def *pos, nir_ssa_def *mcs,
> +                 enum brw_reg_type dst_type)
> +{
> +   nir_tex_instr *tex =
> +      blorp_create_nir_tex_instr(b->shader, nir_texop_txf_ms, pos,
> +                                 mcs != NULL ? 3 : 2, dst_type);
> +
> +   tex->sampler_dim = GLSL_SAMPLER_DIM_MS;
> +   tex->coord_components = 2;
> +   tex->src[0].src_type = nir_tex_src_coord;
> +   tex->src[0].src = nir_src_for_ssa(pos);
> +
> +   tex->src[1].src_type = nir_tex_src_ms_index;
> +   if (pos->num_components == 2) {
> +      tex->src[1].src = nir_src_for_ssa(nir_imm_int(b, 0));
> +   } else {
> +      assert(pos->num_components == 3);
> +      tex->src[1].src = nir_src_for_ssa(nir_channel(b, pos, 2));
> +   }
> +
> +   if (mcs) {
> +      tex->src[2].src_type = nir_tex_src_ms_mcs;
> +      tex->src[2].src = nir_src_for_ssa(mcs);
> +   }
> +
> +   nir_builder_instr_insert(b, &tex->instr);
> +
> +   return &tex->dest.ssa;
> +}
> +
> +static nir_ssa_def *
> +blorp_nir_txf_ms_mcs(nir_builder *b, nir_ssa_def *pos)
> +{
> +   nir_tex_instr *tex =
> +      blorp_create_nir_tex_instr(b->shader, nir_texop_txf_ms_mcs,
> +                                 pos, 1, BRW_REGISTER_TYPE_D);
> +
> +   tex->sampler_dim = GLSL_SAMPLER_DIM_MS;
> +   tex->coord_components = 2;
> +   tex->src[0].src_type = nir_tex_src_coord;
> +   tex->src[0].src = nir_src_for_ssa(pos);
> +
> +   nir_builder_instr_insert(b, &tex->instr);
> +
> +   return &tex->dest.ssa;
> +}
> +
>  /**
>   * Generator for WM programs used in BLORP blits.
>   *
> @@ -471,6 +693,161 @@ enum sampler_message_arg
>   * (In these formulas, pitch is the number of bytes occupied by a single row
>   * of samples).
>   */
> +static nir_shader *
> +brw_blorp_build_nir_shader(struct brw_context *brw,
> +                           const brw_blorp_blit_prog_key *key,
> +                           struct brw_blorp_prog_data *prog_data)
> +{
> +   nir_ssa_def *src_pos, *dst_pos, *color;
> +
> +   /* Sanity checks */
> +   if (key->dst_tiled_w && key->rt_samples > 0) {
> +      /* If the destination image is W tiled and multisampled, then the thread
> +       * must be dispatched once per sample, not once per pixel.  This is
> +       * necessary because after conversion between W and Y tiling, there's no
> +       * guarantee that all samples corresponding to a single pixel will still
> +       * be together.
> +       */
> +      assert(key->persample_msaa_dispatch);
> +   }
> +
> +   if (key->blend) {
> +      /* We are blending, which means we won't have an opportunity to
> +       * translate the tiling and sample count for the texture surface.  So
> +       * the surface state for the texture must be configured with the correct
> +       * tiling and sample count.
> +       */
> +      assert(!key->src_tiled_w);
> +      assert(key->tex_samples == key->src_samples);
> +      assert(key->tex_layout == key->src_layout);
> +      assert(key->tex_samples > 0);
> +   }
> +
> +   if (key->persample_msaa_dispatch) {
> +      /* It only makes sense to do persample dispatch if the render target is
> +       * configured as multisampled.
> +       */
> +      assert(key->rt_samples > 0);
> +   }
> +
> +   /* Make sure layout is consistent with sample count */
> +   assert((key->tex_layout == INTEL_MSAA_LAYOUT_NONE) ==
> +          (key->tex_samples == 0));
> +   assert((key->rt_layout == INTEL_MSAA_LAYOUT_NONE) ==
> +          (key->rt_samples == 0));
> +   assert((key->src_layout == INTEL_MSAA_LAYOUT_NONE) ==
> +          (key->src_samples == 0));
> +   assert((key->dst_layout == INTEL_MSAA_LAYOUT_NONE) ==
> +          (key->dst_samples == 0));
> +
> +   /* Set up prog_data */
> +   brw_blorp_prog_data_init(prog_data);
> +
> +   nir_builder b;
> +   nir_builder_init_simple_shader(&b, NULL, MESA_SHADER_FRAGMENT, NULL);
> +
> +   struct brw_blorp_blit_vars v;
> +   brw_blorp_blit_vars_init(&b, &v, key);
> +
> +   dst_pos = blorp_blit_get_frag_coords(&b, key, &v);
> +
> +   /* Render target and texture hardware don't support W tiling until Gen8. */
> +   const bool rt_tiled_w = false;
> +   const bool tex_tiled_w = brw->gen >= 8 && key->src_tiled_w;
> +
> +   /* The address that data will be written to is determined by the
> +    * coordinates supplied to the WM thread and the tiling and sample count of
> +    * the render target, according to the formula:
> +    *
> +    * (X, Y, S) = decode_msaa(rt_samples, detile(rt_tiling, offset))
> +    *
> +    * If the actual tiling and sample count of the destination surface are not
> +    * the same as the configuration of the render target, then these
> +    * coordinates are wrong and we have to adjust them to compensate for the
> +    * difference.
> +    */
> +   if (rt_tiled_w != key->dst_tiled_w ||
> +       key->rt_samples != key->dst_samples ||
> +       key->rt_layout != key->dst_layout) {
> +      goto fail;
> +   }
> +
> +   /* Now (X, Y, S) = decode_msaa(dst_samples, detile(dst_tiling, offset)).
> +    *
> +    * That is: X, Y and S now contain the true coordinates and sample index of
> +    * the data that the WM thread should output.
> +    *
> +    * If we need to kill pixels that are outside the destination rectangle,
> +    * now is the time to do it.
> +    */
> +   if (key->use_kill)
> +      goto fail;
> +
> +   src_pos = blorp_blit_apply_transform(&b, nir_i2f(&b, dst_pos), &v);
> +
> +   if (key->blit_scaled && key->blend) {
> +      goto fail;
> +   } else if (!key->bilinear_filter) {
> +      /* We're going to use a texelFetch, so we need integers */
> +      src_pos = nir_f2i(&b, src_pos);
> +   }
> +
> +   /* X, Y, and S are now the coordinates of the pixel in the source image
> +    * that we want to texture from.  Exception: if we are blending, then S is
> +    * irrelevant, because we are going to fetch all samples.
> +    */
> +   if (key->blend && !key->blit_scaled) {
> +      goto fail;
> +   } else if (key->blend && key->blit_scaled) {
> +      goto fail;
> +   } else {
> +      /* We aren't blending, which means we just want to fetch a single sample
> +       * from the source surface.  The address that we want to fetch from is
> +       * related to the X, Y and S values according to the formula:
> +       *
> +       * (X, Y, S) = decode_msaa(src_samples, detile(src_tiling, offset)).
> +       *
> +       * If the actual tiling and sample count of the source surface are not
> +       * the same as the configuration of the texture, then we need to adjust
> +       * the coordinates to compensate for the difference.
> +       */
> +      if ((tex_tiled_w != key->src_tiled_w ||
> +           key->tex_samples != key->src_samples ||
> +           key->tex_layout != key->src_layout) &&
> +          !key->bilinear_filter) {
> +         goto fail;
> +      }
> +
> +      if (key->bilinear_filter) {
> +         color = blorp_nir_tex(&b, src_pos, key->texture_data_type);
> +      } else {
> +         /* Now (X, Y, S) = decode_msaa(tex_samples, detile(tex_tiling, offset)).
> +          *
> +          * In other words: X, Y, and S now contain values which, when passed to
> +          * the texturing unit, will cause data to be read from the correct
> +          * memory location.  So we can fetch the texel now.
> +          */
> +         if (key->src_samples == 0) {

Hmm, src_samples can be one also, right? It get its value directly from the
miptree. I think we will end up with lossless compression to take the mcs
fetch path. Should we instead use:

            if (key->src_samples <= 1) {

Other than that:

Reviewed-by: Topi Pohjolainen <topi.pohjolainen at intel.com>

> +            color = blorp_nir_txf(&b, &v, src_pos, key->texture_data_type);
> +         } else {
> +            nir_ssa_def *mcs = NULL;
> +            if (key->tex_layout == INTEL_MSAA_LAYOUT_CMS)
> +               mcs = blorp_nir_txf_ms_mcs(&b, src_pos);
> +
> +            color = blorp_nir_txf_ms(&b, src_pos, mcs, key->texture_data_type);
> +         }
> +      }
> +   }
> +
> +   nir_store_var(&b, v.color_out, color, 0xf);
> +
> +   return b.shader;
> +
> +fail:
> +   ralloc_free(b.shader);
> +   return NULL;
> +}
> +
>  class brw_blorp_blit_program : public brw_blorp_eu_emitter
>  {
>  public:
> @@ -1307,25 +1684,6 @@ brw_blorp_blit_program::clamp_tex_coords(struct brw_reg regX,
>     emit_min(regY, regY, clampY1);
>  }
>  
> -/**
> - * Emit code to transform the X and Y coordinates as needed for blending
> - * together the different samples in an MSAA texture.
> - */
> -void
> -brw_blorp_blit_program::single_to_blend()
> -{
> -   /* When looking up samples in an MSAA texture using the SAMPLE message,
> -    * Gen6 requires the texture coordinates to be odd integers (so that they
> -    * correspond to the center of a 2x2 block representing the four samples
> -    * that maxe up a pixel).  So we need to multiply our X and Y coordinates
> -    * each by 2 and then add 1.
> -    */
> -   emit_shl(t1, X, brw_imm_w(1));
> -   emit_shl(t2, Y, brw_imm_w(1));
> -   emit_add(Xp, t1, brw_imm_w(1));
> -   emit_add(Yp, t2, brw_imm_w(1));
> -   SWAP_XY_AND_XPYP();
> -}
>  
>  
>  /**
> @@ -1747,14 +2105,33 @@ brw_blorp_get_blit_kernel(struct brw_context *brw,
>                          &params->wm_prog_kernel, &params->wm_prog_data))
>        return;
>  
> -   brw_blorp_blit_program prog(brw, prog_key);
> -   GLuint program_size;
> -   const GLuint *program = prog.compile(brw, INTEL_DEBUG & DEBUG_BLORP,
> -                                        &program_size);
> +   const unsigned *program;
> +   unsigned program_size;
> +   struct brw_blorp_prog_data prog_data;
> +
> +   /* Try and compile with NIR first.  If that fails, fall back to the old
> +    * method of building shaders manually.
> +    */
> +   nir_shader *nir = brw_blorp_build_nir_shader(brw, prog_key, &prog_data);
> +   if (nir) {
> +      struct brw_wm_prog_key wm_key;
> +      brw_blorp_init_wm_prog_key(&wm_key);
> +      wm_key.tex.compressed_multisample_layout_mask =
> +         prog_key->tex_layout == INTEL_MSAA_LAYOUT_CMS;
> +      wm_key.multisample_fbo = prog_key->rt_samples > 1;
> +
> +      program = brw_blorp_compile_nir_shader(brw, nir, &wm_key, false,
> +                                             &prog_data, &program_size);
> +   } else {
> +      brw_blorp_blit_program prog(brw, prog_key);
> +      program = prog.compile(brw, INTEL_DEBUG & DEBUG_BLORP, &program_size);
> +      prog_data = prog.prog_data;
> +   }
> +
>     brw_upload_cache(&brw->cache, BRW_CACHE_BLORP_PROG,
>                      prog_key, sizeof(*prog_key),
>                      program, program_size,
> -                    &prog.prog_data, sizeof(prog.prog_data),
> +                    &prog_data, sizeof(prog_data),
>                      &params->wm_prog_kernel, &params->wm_prog_data);
>  }
>  
> -- 
> 2.5.0.400.gff86faf
> 
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