nir: Make gl_nir_lower_samplers use gl_nir_lower_samplers_as_deref

These days, we have two sampler lowering passes.  The newer one,
gl_nir_lower_samplers_as_deref, is used by radeonsi.  It rewrites
variables to drop structures out of sampler deref chains, to make
life simpler.  It then sets var->data.binding for non-bindless
sampler and image variables based on the GL uniform storage's
opaque index values.

The older one converts sampler deref chains (nir_tex_src_texture_deref)
to a numerical offset (nir_tex_src_texture_offset).  It also stores the
constant-valued portion of that number in tex->texture_index, making
life really simple for drivers that don't support indirects.  It too
pokes at GL uniform storage's opaque index values.

Logically, we can do the first pass (simplify derefs, set bindings)
then the second (turn derefs to offsets, set texture_index).  This
patch does exactly that, eliminating some redundancy (only one pass
has to poke at GL uniform storage), and gaining proper var->data.binding
values for drivers using the full lowering.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>

diff --git a/src/compiler/glsl/gl_nir_lower_samplers.c b/src/compiler/glsl/gl_nir_lower_samplers.c
index 1ee075cfd142f2542ae95ce09e887745b361b5a0..85535c074dcc26e326e62626af47f910bbd71d67 100644 (file)
--- a/src/compiler/glsl/gl_nir_lower_samplers.c
+++ b/src/compiler/glsl/gl_nir_lower_samplers.c
@@ -33,15 +33,13 @@
 
 static void
 lower_tex_src_to_offset(nir_builder *b,
-                        nir_tex_instr *instr, unsigned src_idx,
-                        const struct gl_shader_program *shader_program)
+                        nir_tex_instr *instr, unsigned src_idx)
 {
    nir_ssa_def *index = NULL;
    unsigned base_index = 0;
    unsigned array_elements = 1;
    nir_tex_src *src = &instr->src[src_idx];
    bool is_sampler = src->src_type == nir_tex_src_sampler_deref;
-   unsigned location = 0;
 
    /* We compute first the offsets */
    nir_deref_instr *deref = nir_instr_as_deref(src->src.ssa->parent_instr);
@@ -50,35 +48,24 @@ lower_tex_src_to_offset(nir_builder *b,
       nir_deref_instr *parent =
          nir_instr_as_deref(deref->parent.ssa->parent_instr);
 
-      switch (deref->deref_type) {
-      case nir_deref_type_struct:
-         location += glsl_get_record_location_offset(parent->type,
-                                                     deref->strct.index);
-         break;
-
-      case nir_deref_type_array: {
-         if (nir_src_is_const(deref->arr.index) && index == NULL) {
-            /* We're still building a direct index */
-            base_index += nir_src_as_uint(deref->arr.index) * array_elements;
-         } else {
-            if (index == NULL) {
-               /* We used to be direct but not anymore */
-               index = nir_imm_int(b, base_index);
-               base_index = 0;
-            }
-
-            index = nir_iadd(b, index,
-                             nir_imul(b, nir_imm_int(b, array_elements),
-                                      nir_ssa_for_src(b, deref->arr.index, 1)));
+      assert(deref->deref_type == nir_deref_type_array);
+
+      if (nir_src_is_const(deref->arr.index) && index == NULL) {
+         /* We're still building a direct index */
+         base_index += nir_src_as_uint(deref->arr.index) * array_elements;
+      } else {
+         if (index == NULL) {
+            /* We used to be direct but not anymore */
+            index = nir_imm_int(b, base_index);
+            base_index = 0;
          }
 
-         array_elements *= glsl_get_length(parent->type);
-         break;
+         index = nir_iadd(b, index,
+                          nir_imul(b, nir_imm_int(b, array_elements),
+                                   nir_ssa_for_src(b, deref->arr.index, 1)));
       }
 
-      default:
-         unreachable("Invalid sampler deref type");
-      }
+      array_elements *= glsl_get_length(parent->type);
 
       deref = parent;
    }
@@ -89,14 +76,7 @@ lower_tex_src_to_offset(nir_builder *b,
    /* We hit the deref_var.  This is the end of the line */
    assert(deref->deref_type == nir_deref_type_var);
 
-   location += deref->var->data.location;
-
-   gl_shader_stage stage = b->shader->info.stage;
-   assert(location < shader_program->data->NumUniformStorage &&
-          shader_program->data->UniformStorage[location].opaque[stage].active);
-
-   base_index +=
-      shader_program->data->UniformStorage[location].opaque[stage].index;
+   base_index += deref->var->data.binding;
 
    /* We have the offsets, we apply them, rewriting the source or removing
     * instr if needed
@@ -123,8 +103,7 @@ lower_tex_src_to_offset(nir_builder *b,
 }
 
 static bool
-lower_sampler(nir_builder *b, nir_tex_instr *instr,
-              const struct gl_shader_program *shader_program)
+lower_sampler(nir_builder *b, nir_tex_instr *instr)
 {
    int texture_idx =
       nir_tex_instr_src_index(instr, nir_tex_src_texture_deref);
@@ -132,16 +111,14 @@ lower_sampler(nir_builder *b, nir_tex_instr *instr,
    if (texture_idx >= 0) {
       b->cursor = nir_before_instr(&instr->instr);
 
-      lower_tex_src_to_offset(b, instr, texture_idx,
-                              shader_program);
+      lower_tex_src_to_offset(b, instr, texture_idx);
    }
 
    int sampler_idx =
       nir_tex_instr_src_index(instr, nir_tex_src_sampler_deref);
 
    if (sampler_idx >= 0) {
-      lower_tex_src_to_offset(b, instr, sampler_idx,
-                              shader_program);
+      lower_tex_src_to_offset(b, instr, sampler_idx);
    }
 
    if (texture_idx < 0 && sampler_idx < 0)
@@ -151,8 +128,7 @@ lower_sampler(nir_builder *b, nir_tex_instr *instr,
 }
 
 static bool
-lower_impl(nir_function_impl *impl,
-           const struct gl_shader_program *shader_program)
+lower_impl(nir_function_impl *impl)
 {
    nir_builder b;
    nir_builder_init(&b, impl);
@@ -161,8 +137,7 @@ lower_impl(nir_function_impl *impl,
    nir_foreach_block(block, impl) {
       nir_foreach_instr(instr, block) {
          if (instr->type == nir_instr_type_tex)
-            progress |= lower_sampler(&b, nir_instr_as_tex(instr),
-                                      shader_program);
+            progress |= lower_sampler(&b, nir_instr_as_tex(instr));
       }
    }
 
@@ -175,9 +150,15 @@ gl_nir_lower_samplers(nir_shader *shader,
 {
    bool progress = false;
 
+   /* First, use gl_nir_lower_samplers_as_derefs to set var->data.binding
+    * based on the uniforms, and split structures to simplify derefs.
+    */
+   gl_nir_lower_samplers_as_deref(shader, shader_program);
+
+   /* Next, lower derefs to offsets. */
    nir_foreach_function(function, shader) {
       if (function->impl)
-         progress |= lower_impl(function->impl, shader_program);
+         progress |= lower_impl(function->impl);
    }
 
    return progress;