glsl/nir: add support for lowering bindless images_derefs

v2: handle atomics as well
    make use of nir_rewrite_image_intrinsic
v3: remove call to nir_remove_dead_derefs
v4: (Timothy Arceri) dont actually call lowering yet

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> (v3)
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/compiler/Makefile.sources

@@ -26,6 +26,7 @@ LIBGLSL_FILES = \
 	glsl/builtin_variables.cpp \
 	glsl/generate_ir.cpp \
 	glsl/gl_nir_lower_atomics.c \
+	glsl/gl_nir_lower_bindless_images.c \
 	glsl/gl_nir_lower_buffers.c \
 	glsl/gl_nir_lower_samplers.c \
 	glsl/gl_nir_lower_samplers_as_deref.c \

src/compiler/glsl/gl_nir.h

@@ -35,6 +35,7 @@ bool gl_nir_lower_atomics(nir_shader *shader,
                           const struct gl_shader_program *shader_program,
                           bool use_binding_as_idx);
 
+bool gl_nir_lower_bindless_images(nir_shader *shader);
 bool gl_nir_lower_samplers(nir_shader *shader,
                            const struct gl_shader_program *shader_program);
 bool gl_nir_lower_samplers_as_deref(nir_shader *shader,

src/compiler/glsl/gl_nir_lower_bindless_images.c

@@ -0,0 +1,97 @@
+/*
+ * Copyright © 2019 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file
+ *
+ * Lower bindless image operations by turning the image_deref_* into a
+ * bindless_image_* intrinsic and adding a load_deref on the previous deref
+ * source. All applicable indicies are also set so that fetching the variable
+ * in the backend wouldn't be needed anymore.
+ */
+
+#include "compiler/nir/nir.h"
+#include "compiler/nir/nir_builder.h"
+#include "compiler/nir/nir_deref.h"
+
+#include "compiler/glsl/gl_nir.h"
+
+static bool
+lower_impl(nir_builder *b, nir_instr *instr) {
+   if (instr->type != nir_instr_type_intrinsic)
+      return false;
+
+   nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
+
+   nir_deref_instr *deref;
+   nir_variable *var;
+
+   switch (intrinsic->intrinsic) {
+   case nir_intrinsic_image_deref_atomic_add:
+   case nir_intrinsic_image_deref_atomic_min:
+   case nir_intrinsic_image_deref_atomic_max:
+   case nir_intrinsic_image_deref_atomic_and:
+   case nir_intrinsic_image_deref_atomic_or:
+   case nir_intrinsic_image_deref_atomic_xor:
+   case nir_intrinsic_image_deref_atomic_exchange:
+   case nir_intrinsic_image_deref_atomic_comp_swap:
+   case nir_intrinsic_image_deref_atomic_fadd:
+   case nir_intrinsic_image_deref_load:
+   case nir_intrinsic_image_deref_samples:
+   case nir_intrinsic_image_deref_size:
+   case nir_intrinsic_image_deref_store: {
+      deref = nir_src_as_deref(intrinsic->src[0]);
+      var = nir_deref_instr_get_variable(deref);
+      break;
+   }
+   default:
+      return false;
+   }
+
+   if (deref->mode == nir_var_uniform && !var->data.bindless)
+      return false;
+
+   b->cursor = nir_before_instr(instr);
+   nir_ssa_def *handle = nir_load_deref(b, deref);
+   nir_rewrite_image_intrinsic(intrinsic, handle, true);
+   return true;
+}
+
+bool
+gl_nir_lower_bindless_images(nir_shader *shader)
+{
+   bool progress = false;
+
+   nir_foreach_function(function, shader) {
+      if (function->impl) {
+         nir_builder b;
+         nir_builder_init(&b, function->impl);
+
+         nir_foreach_block(block, function->impl)
+            nir_foreach_instr(instr, block)
+               progress |= lower_impl(&b, instr);
+      }
+   }
+
+   return progress;
+}

src/compiler/glsl/meson.build

@@ -74,6 +74,7 @@ files_libglsl = files(
   'builtin_variables.cpp',
   'generate_ir.cpp',
   'gl_nir_lower_atomics.c',
+  'gl_nir_lower_bindless_images.c',
   'gl_nir_lower_buffers.c',
   'gl_nir_lower_samplers.c',
   'gl_nir_lower_samplers_as_deref.c',

src/compiler/nir/nir.c

@@ -1991,12 +1991,14 @@ nir_get_single_slot_attribs_mask(uint64_t attribs, uint64_t dual_slot)
 }
 
 void
-nir_rewrite_image_intrinsic(nir_intrinsic_instr *intrin, nir_ssa_def *src)
+nir_rewrite_image_intrinsic(nir_intrinsic_instr *intrin, nir_ssa_def *src,
+                            bool bindless)
 {
    switch (intrin->intrinsic) {
 #define CASE(op) \
    case nir_intrinsic_image_deref_##op: \
-      intrin->intrinsic = nir_intrinsic_image_##op; \
+      intrin->intrinsic = bindless ? nir_intrinsic_bindless_image_##op \
+                                   : nir_intrinsic_image_##op; \
       break;
    CASE(load)
    CASE(store)

src/compiler/nir/nir.h

@@ -1409,7 +1409,7 @@ nir_intrinsic_align(const nir_intrinsic_instr *intrin)
 
 /* Converts a image_deref_* intrinsic into a image_* one */
 void nir_rewrite_image_intrinsic(nir_intrinsic_instr *instr,
-                                 nir_ssa_def *handle);
+                                 nir_ssa_def *handle, bool bindless);
 
 /**
  * \group texture information

src/gallium/drivers/iris/iris_program.c

@@ -146,7 +146,7 @@ iris_lower_storage_image_derefs(nir_shader *nir)
             nir_ssa_def *index =
                nir_iadd(&b, nir_imm_int(&b, var->data.driver_location),
                             get_aoa_deref_offset(&b, deref, 1));
-            nir_rewrite_image_intrinsic(intrin, index);
+            nir_rewrite_image_intrinsic(intrin, index, false);
             break;
          }
 

src/intel/vulkan/anv_nir_apply_pipeline_layout.c

@@ -292,7 +292,7 @@ lower_image_intrinsic(nir_intrinsic_instr *intrin,
    } else {
       unsigned binding_offset = state->set[set].surface_offsets[binding];
       index = nir_iadd(b, index, nir_imm_int(b, binding_offset));
-      nir_rewrite_image_intrinsic(intrin, index);
+      nir_rewrite_image_intrinsic(intrin, index, false);
    }
 }
 

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

@@ -347,7 +347,7 @@ brw_nir_lower_gl_images(nir_shader *shader,
             b.cursor = nir_before_instr(&intrin->instr);
             nir_ssa_def *index = nir_iadd(&b, nir_imm_int(&b, image_var_idx),
                                           get_aoa_deref_offset(&b, deref, 1));
-            nir_rewrite_image_intrinsic(intrin, index);
+            nir_rewrite_image_intrinsic(intrin, index, false);
             break;
          }