nir/spirv: Add support for separate samplers and textures

This gets tricky in a few places because we have to pass vtn_sampled_image
values through OpAccessChain, but it works ok.  At some point, it probably
needs to be cleaned up but it doesn't occur to me exactly how to do that at
the moment.  We'll see how this approach goes.

2 files changed, 87 insertions, 16 deletions

diff --git a/src/glsl/nir/spirv_to_nir.c b/src/glsl/nir/spirv_to_nir.c
index 740479f4d20..024988e06ef 100644
--- a/src/glsl/nir/spirv_to_nir.c
+++ b/src/glsl/nir/spirv_to_nir.c
@@ -617,6 +617,19 @@ vtn_handle_type(struct vtn_builder *b, SpvOp opcode,
       val->type = vtn_value(b, w[2], vtn_value_type_type)->type;
       break;
 
+   case SpvOpTypeSampler:
+      /* The actual sampler type here doesn't really matter.  It gets
+       * thrown away the moment you combine it with an image.  What really
+       * matters is that it's a sampler type as opposed to an integer type
+       * so the backend knows what to do.
+       *
+       * TODO: Eventually we should consider adding a "bare sampler" type
+       * to glsl_types.
+       */
+      val->type->type = glsl_sampler_type(GLSL_SAMPLER_DIM_2D, false, false,
+                                          GLSL_TYPE_FLOAT);
+      break;
+
    case SpvOpTypeRuntimeArray:
    case SpvOpTypeOpaque:
    case SpvOpTypeEvent:
@@ -1603,12 +1616,26 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
 
    case SpvOpAccessChain:
    case SpvOpInBoundsAccessChain: {
-      struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_deref);
-      nir_deref_var *base = vtn_value(b, w[3], vtn_value_type_deref)->deref;
-      val->deref = nir_deref_as_var(nir_copy_deref(b, &base->deref));
+      nir_deref_var *base;
+      struct vtn_value *base_val = vtn_untyped_value(b, w[3]);
+      if (base_val->value_type == vtn_value_type_sampled_image) {
+         /* This is rather insane.  SPIR-V allows you to use OpSampledImage
+          * to combine an array of images with a single sampler to get an
+          * array of sampled images that all share the same sampler.
+          * Fortunately, this means that we can more-or-less ignore the
+          * sampler when crawling the access chain, but it does leave us
+          * with this rather awkward little special-case.
+          */
+         base = base_val->sampled_image->image;
+      } else {
+         assert(base_val->value_type == vtn_value_type_deref);
+         base = base_val->deref;
+      }
+
+      nir_deref_var *deref = nir_deref_as_var(nir_copy_deref(b, &base->deref));
       struct vtn_type *deref_type = vtn_value(b, w[3], vtn_value_type_deref)->deref_type;
 
-      nir_deref *tail = &val->deref->deref;
+      nir_deref *tail = &deref->deref;
       while (tail->child)
          tail = tail->child;
 
@@ -1679,29 +1706,29 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
                                               b->shader->info.gs.vertices_in);
 
                /* The first non-var deref should be an array deref. */
-               assert(val->deref->deref.child->deref_type ==
+               assert(deref->deref.child->deref_type ==
                       nir_deref_type_array);
-               per_vertex_deref = nir_deref_as_array(val->deref->deref.child);
+               per_vertex_deref = nir_deref_as_array(deref->deref.child);
             }
 
             nir_variable *builtin = get_builtin_variable(b,
                                                          base->var->data.mode,
                                                          builtin_type,
                                                          deref_type->builtin);
-            val->deref = nir_deref_var_create(b, builtin);
+            deref = nir_deref_var_create(b, builtin);
 
             if (per_vertex_deref) {
                /* Since deref chains start at the variable, we can just
                 * steal that link and use it.
                 */
-               val->deref->deref.child = &per_vertex_deref->deref;
+               deref->deref.child = &per_vertex_deref->deref;
                per_vertex_deref->deref.child = NULL;
                per_vertex_deref->deref.type =
                   glsl_get_array_element(builtin_type);
 
                tail = &per_vertex_deref->deref;
             } else {
-               tail = &val->deref->deref;
+               tail = &deref->deref;
             }
          } else {
             tail = tail->child;
@@ -1712,12 +1739,20 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
        * actually access the variable, so we need to keep around the original
        * type of the variable.
        */
-
       if (variable_is_external_block(base->var))
-         val->deref_type = vtn_value(b, w[3], vtn_value_type_deref)->deref_type;
-      else
+         deref_type = vtn_value(b, w[3], vtn_value_type_deref)->deref_type;
+
+      if (base_val->value_type == vtn_value_type_sampled_image) {
+         struct vtn_value *val =
+            vtn_push_value(b, w[2], vtn_value_type_sampled_image);
+         val->sampled_image = ralloc(b, struct vtn_sampled_image);
+         val->sampled_image->image = deref;
+         val->sampled_image->sampler = base_val->sampled_image->sampler;
+      } else {
+         struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_deref);
+         val->deref = deref;
          val->deref_type = deref_type;
-
+      }
 
       break;
    }
@@ -1822,8 +1857,28 @@ static void
 vtn_handle_texture(struct vtn_builder *b, SpvOp opcode,
                    const uint32_t *w, unsigned count)
 {
+   if (opcode == SpvOpSampledImage) {
+      struct vtn_value *val =
+         vtn_push_value(b, w[2], vtn_value_type_sampled_image);
+      val->sampled_image = ralloc(b, struct vtn_sampled_image);
+      val->sampled_image->image =
+         vtn_value(b, w[3], vtn_value_type_deref)->deref;
+      val->sampled_image->sampler =
+         vtn_value(b, w[4], vtn_value_type_deref)->deref;
+      return;
+   }
+
    struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
-   nir_deref_var *sampler = vtn_value(b, w[3], vtn_value_type_deref)->deref;
+
+   struct vtn_sampled_image sampled;
+   struct vtn_value *sampled_val = vtn_untyped_value(b, w[3]);
+   if (sampled_val->value_type == vtn_value_type_sampled_image) {
+      sampled = *sampled_val->sampled_image;
+   } else {
+      assert(sampled_val->value_type == vtn_value_type_deref);
+      sampled.image = NULL;
+      sampled.sampler = sampled_val->deref;
+   }
 
    nir_tex_src srcs[8]; /* 8 should be enough */
    nir_tex_src *p = srcs;
@@ -1954,7 +2009,8 @@ vtn_handle_texture(struct vtn_builder *b, SpvOp opcode,
 
    nir_tex_instr *instr = nir_tex_instr_create(b->shader, p - srcs);
 
-   const struct glsl_type *sampler_type = nir_deref_tail(&sampler->deref)->type;
+   const struct glsl_type *sampler_type =
+      nir_deref_tail(&sampled.sampler->deref)->type;
    instr->sampler_dim = glsl_get_sampler_dim(sampler_type);
 
    switch (glsl_get_sampler_result_type(sampler_type)) {
@@ -1972,7 +2028,14 @@ vtn_handle_texture(struct vtn_builder *b, SpvOp opcode,
    instr->is_array = glsl_sampler_type_is_array(sampler_type);
    instr->is_shadow = glsl_sampler_type_is_shadow(sampler_type);
 
-   instr->sampler = nir_deref_as_var(nir_copy_deref(instr, &sampler->deref));
+   instr->sampler =
+      nir_deref_as_var(nir_copy_deref(instr, &sampled.sampler->deref));
+   if (sampled.image) {
+      instr->texture =
+         nir_deref_as_var(nir_copy_deref(instr, &sampled.image->deref));
+   } else {
+      instr->texture = NULL;
+   }
 
    nir_ssa_dest_init(&instr->instr, &instr->dest, 4, NULL);
    val->ssa = vtn_create_ssa_value(b, glsl_vector_type(GLSL_TYPE_FLOAT, 4));
@@ -3310,6 +3373,7 @@ vtn_handle_body_instruction(struct vtn_builder *b, SpvOp opcode,
       vtn_handle_function_call(b, opcode, w, count);
       break;
 
+   case SpvOpSampledImage:
    case SpvOpImageSampleImplicitLod:
    case SpvOpImageSampleExplicitLod:
    case SpvOpImageSampleDrefImplicitLod:
diff --git a/src/glsl/nir/spirv_to_nir_private.h b/src/glsl/nir/spirv_to_nir_private.h
index f7be166da16..40f0c78ae78 100644
--- a/src/glsl/nir/spirv_to_nir_private.h
+++ b/src/glsl/nir/spirv_to_nir_private.h
@@ -46,6 +46,7 @@ enum vtn_value_type {
    vtn_value_type_ssa,
    vtn_value_type_extension,
    vtn_value_type_image_pointer,
+   vtn_value_type_sampled_image,
 };
 
 struct vtn_block {
@@ -127,6 +128,11 @@ struct vtn_image_pointer {
    nir_ssa_def *sample;
 };
 
+struct vtn_sampled_image {
+   nir_deref_var *image; /* Image or array of images */
+   nir_deref_var *sampler; /* Sampler */
+};
+
 struct vtn_value {
    enum vtn_value_type value_type;
    const char *name;
@@ -144,6 +150,7 @@ struct vtn_value {
          struct vtn_type *deref_type;
       };
       struct vtn_image_pointer *image;
+      struct vtn_sampled_image *sampled_image;
       struct vtn_function *func;
       struct vtn_block *block;
       struct vtn_ssa_value *ssa;