nir: Separate texture from sampler in nir_tex_instr

This commit adds the capability to NIR to support separate textures and
samplers.  As it currently stands, glsl_to_nir only sets the texture deref
and leaves the sampler deref alone as it did before and nir_lower_samplers
assumes this.  Backends can still assume that they are combined and only
look at only at the texture index.  Or, if they wish, they can assume that
they are separate because nir_lower_samplers, tgsi_to_nir, and prog_to_nir
all set both texture and sampler index whenever a sampler is required (the
two indices are the same in this case).

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/nir/nir.c

@@ -489,6 +489,8 @@ nir_tex_instr_create(nir_shader *shader, unsigned num_srcs)
    instr->texture_index = 0;
    instr->texture_array_size = 0;
    instr->texture = NULL;
+   instr->sampler_index = 0;
+   instr->sampler = NULL;
 
    return instr;
 }
@@ -1012,6 +1014,11 @@ visit_tex_src(nir_tex_instr *instr, nir_foreach_src_cb cb, void *state)
          return false;
    }
 
+   if (instr->sampler != NULL) {
+      if (!visit_deref_src(instr->sampler, cb, state))
+         return false;
+   }
+
    return true;
 }
 

src/compiler/nir/nir.h

@@ -966,6 +966,7 @@ typedef enum {
    nir_tex_src_ddx,
    nir_tex_src_ddy,
    nir_tex_src_texture_offset, /* < dynamically uniform indirect offset */
+   nir_tex_src_sampler_offset, /* < dynamically uniform indirect offset */
    nir_num_tex_src_types
 } nir_tex_src_type;
 
@@ -1025,7 +1026,35 @@ typedef struct {
    /** The size of the texture array or 0 if it's not an array */
    unsigned texture_array_size;
 
-   nir_deref_var *texture; /* if this is NULL, use texture_index instead */
+   /** The texture deref
+    *
+    * If this is null, use texture_index instead.
+    */
+   nir_deref_var *texture;
+
+   /** The sampler index
+    *
+    * The following operations do not require a sampler and, as such, this
+    * field should be ignored:
+    *    - nir_texop_txf
+    *    - nir_texop_txf_ms
+    *    - nir_texop_txs
+    *    - nir_texop_lod
+    *    - nir_texop_tg4
+    *    - nir_texop_query_levels
+    *    - nir_texop_texture_samples
+    *    - nir_texop_samples_identical
+    *
+    * If this texture instruction has a nir_tex_src_sampler_offset source,
+    * then the sampler index is given by sampler_index + sampler_offset.
+    */
+   unsigned sampler_index;
+
+   /** The sampler deref
+    *
+    * If this is null, use sampler_index instead.
+    */
+   nir_deref_var *sampler;
 } nir_tex_instr;
 
 static inline unsigned

src/compiler/nir/nir_clone.c

@@ -357,10 +357,15 @@ clone_tex(clone_state *state, const nir_tex_instr *tex)
    ntex->is_new_style_shadow = tex->is_new_style_shadow;
    memcpy(ntex->const_offset, tex->const_offset, sizeof(ntex->const_offset));
    ntex->component = tex->component;
+
    ntex->texture_index = tex->texture_index;
-   ntex->texture_array_size = tex->texture_array_size;
    if (tex->texture)
       ntex->texture = clone_deref_var(state, tex->texture, &ntex->instr);
+   ntex->texture_array_size = tex->texture_array_size;
+
+   ntex->sampler_index = tex->sampler_index;
+   if (tex->sampler)
+      ntex->sampler = clone_deref_var(state, tex->sampler, &ntex->instr);
 
    return ntex;
 }

src/compiler/nir/nir_instr_set.c

@@ -157,8 +157,9 @@ hash_tex(uint32_t hash, const nir_tex_instr *instr)
    hash = HASH(hash, component);
    hash = HASH(hash, instr->texture_index);
    hash = HASH(hash, instr->texture_array_size);
+   hash = HASH(hash, instr->sampler_index);
 
-   assert(!instr->texture);
+   assert(!instr->texture && !instr->sampler);
 
    return hash;
 }
@@ -306,12 +307,14 @@ nir_instrs_equal(const nir_instr *instr1, const nir_instr *instr2)
                  sizeof(tex1->const_offset)) != 0 ||
           tex1->component != tex2->component ||
          tex1->texture_index != tex2->texture_index ||
-         tex1->texture_array_size != tex2->texture_array_size) {
+         tex1->texture_array_size != tex2->texture_array_size ||
+         tex1->sampler_index != tex2->sampler_index) {
          return false;
       }
 
-      /* Don't support un-lowered texture derefs currently. */
+      /* Don't support un-lowered sampler derefs currently. */
-      assert(!tex1->texture && !tex2->texture);
+      assert(!tex1->texture && !tex1->sampler &&
+             !tex2->texture && !tex2->sampler);
 
       return true;
    }
@@ -421,8 +424,8 @@ instr_can_rewrite(nir_instr *instr)
    case nir_instr_type_tex: {
       nir_tex_instr *tex = nir_instr_as_tex(instr);
 
-      /* Don't support un-lowered texture derefs currently. */
+      /* Don't support un-lowered sampler derefs currently. */
-      if (tex->texture)
+      if (tex->texture || tex->sampler)
          return false;
 
       return true;

src/compiler/nir/nir_lower_samplers.c

@@ -94,6 +94,9 @@ lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_progr
    if (instr->texture == NULL)
       return;
 
+   /* In GLSL, we only fill out the texture field.  The sampler is inferred */
+   assert(instr->sampler == NULL);
+
    instr->texture_index = 0;
    unsigned location = instr->texture->var->data.location;
    unsigned array_elements = 1;
@@ -106,7 +109,7 @@ lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_progr
    if (indirect) {
       /* First, we have to resize the array of texture sources */
       nir_tex_src *new_srcs = rzalloc_array(instr, nir_tex_src,
-                                            instr->num_srcs + 1);
+                                            instr->num_srcs + 2);
 
       for (unsigned i = 0; i < instr->num_srcs; i++) {
          new_srcs[i].src_type = instr->src[i].src_type;
@@ -126,6 +129,12 @@ lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_progr
                             &instr->src[instr->num_srcs - 1].src,
                             nir_src_for_ssa(indirect));
 
+      instr->src[instr->num_srcs].src_type = nir_tex_src_sampler_offset;
+      instr->num_srcs++;
+      nir_instr_rewrite_src(&instr->instr,
+                            &instr->src[instr->num_srcs - 1].src,
+                            nir_src_for_ssa(indirect));
+
       instr->texture_array_size = array_elements;
    }
 
@@ -138,6 +147,8 @@ lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_progr
    instr->texture_index +=
       shader_program->UniformStorage[location].opaque[stage].index;
 
+   instr->sampler_index = instr->texture_index;
+
    instr->texture = NULL;
 }
 

src/compiler/nir/nir_lower_tex.c

@@ -291,11 +291,11 @@ nir_lower_tex_block(nir_block *block, void *void_state)
       /* mask of src coords to saturate (clamp): */
       unsigned sat_mask = 0;
 
-      if ((1 << tex->texture_index) & state->options->saturate_r)
+      if ((1 << tex->sampler_index) & state->options->saturate_r)
          sat_mask |= (1 << 2);    /* .z */
-      if ((1 << tex->texture_index) & state->options->saturate_t)
+      if ((1 << tex->sampler_index) & state->options->saturate_t)
          sat_mask |= (1 << 1);    /* .y */
-      if ((1 << tex->texture_index) & state->options->saturate_s)
+      if ((1 << tex->sampler_index) & state->options->saturate_s)
          sat_mask |= (1 << 0);    /* .x */
 
       /* If we are clamping any coords, we must lower projector first

src/compiler/nir/nir_opt_constant_folding.c

@@ -136,10 +136,15 @@ constant_fold_intrinsic_instr(nir_intrinsic_instr *instr)
 static bool
 constant_fold_tex_instr(nir_tex_instr *instr)
 {
+   bool progress = false;
+
    if (instr->texture)
-      return constant_fold_deref(&instr->instr, instr->texture);
+      progress |= constant_fold_deref(&instr->instr, instr->texture);
-   else
+
-      return false;
+   if (instr->sampler)
+      progress |= constant_fold_deref(&instr->instr, instr->sampler);
+
+   return progress;
 }
 
 static bool

src/compiler/nir/nir_print.c

@@ -625,6 +625,9 @@ print_tex_instr(nir_tex_instr *instr, print_state *state)
       case nir_tex_src_texture_offset:
          fprintf(fp, "(texture_offset)");
          break;
+      case nir_tex_src_sampler_offset:
+         fprintf(fp, "(sampler_offset)");
+         break;
 
       default:
          unreachable("Invalid texture source type");
@@ -654,11 +657,16 @@ print_tex_instr(nir_tex_instr *instr, print_state *state)
 
    if (instr->texture) {
       print_deref(instr->texture, state);
+      fprintf(fp, " (texture)");
+      if (instr->sampler) {
+         print_deref(instr->sampler, state);
+         fprintf(fp, " (sampler)");
+      }
    } else {
-      fprintf(fp, "%u", instr->texture_index);
+      assert(instr->sampler == NULL);
+      fprintf(fp, "%u (texture) %u (sampler)",
+              instr->texture_index, instr->sampler_index);
    }
-
-   fprintf(fp, " (texture)");
 }
 
 static void

src/compiler/nir/nir_remove_dead_variables.c

@@ -58,6 +58,11 @@ add_var_use_tex(nir_tex_instr *instr, struct set *live)
       nir_variable *var = instr->texture->var;
       _mesa_set_add(live, var);
    }
+
+   if (instr->sampler != NULL) {
+      nir_variable *var = instr->sampler->var;
+      _mesa_set_add(live, var);
+   }
 }
 
 static bool

src/compiler/nir/nir_validate.c

@@ -448,6 +448,9 @@ validate_tex_instr(nir_tex_instr *instr, validate_state *state)
    if (instr->texture != NULL)
       validate_deref_var(instr, instr->texture, state);
 
+   if (instr->sampler != NULL)
+      validate_deref_var(instr, instr->sampler, state);
+
    validate_dest(&instr->dest, state);
 }
 

src/gallium/auxiliary/nir/tgsi_to_nir.c

@@ -1310,6 +1310,7 @@ ttn_tex(struct ttn_compile *c, nir_alu_dest dest, nir_ssa_def **src)
 
    assert(tgsi_inst->Src[samp].Register.File == TGSI_FILE_SAMPLER);
    instr->texture_index = tgsi_inst->Src[samp].Register.Index;
+   instr->sampler_index = tgsi_inst->Src[samp].Register.Index;
 
    /* TODO if we supported any opc's which take an explicit SVIEW
     * src, we would use that here instead.  But for the "legacy"

src/mesa/drivers/dri/i965/brw_fs_nir.cpp

@@ -3024,6 +3024,9 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
          break;
       }
 
+      case nir_tex_src_sampler_offset:
+         break; /* Ignored for now */
+
       default:
          unreachable("unknown texture source");
       }

src/mesa/drivers/dri/i965/brw_vec4_nir.cpp

@@ -1738,6 +1738,9 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
          break;
       }
 
+      case nir_tex_src_sampler_offset:
+         break; /* Ignored for now */
+
       case nir_tex_src_projector:
          unreachable("Should be lowered by do_lower_texture_projection");
 

src/mesa/program/prog_to_nir.c

@@ -610,6 +610,7 @@ ptn_tex(nir_builder *b, nir_alu_dest dest, nir_ssa_def **src,
    instr->dest_type = nir_type_float;
    instr->is_shadow = prog_inst->TexShadow;
    instr->texture_index = prog_inst->TexSrcUnit;
+   instr->sampler_index = prog_inst->TexSrcUnit;
 
    switch (prog_inst->TexSrcTarget) {
    case TEXTURE_1D_INDEX: