nir: add a pass to lower sampler instructions

1 files changed, 170 insertions, 0 deletions

diff --git a/src/glsl/nir/nir_lower_samplers.cpp b/src/glsl/nir/nir_lower_samplers.cpp
new file mode 100644
index 00000000000..e10456db230
--- /dev/null
+++ b/src/glsl/nir/nir_lower_samplers.cpp
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2005-2007  Brian Paul   All Rights Reserved.
+ * Copyright (C) 2008  VMware, Inc.   All Rights Reserved.
+ * Copyright © 2014 Intel Corporation
+ *
+ * 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.
+ */
+
+#include "nir.h"
+#include "../program.h"
+#include "program/hash_table.h"
+#include "ir_uniform.h"
+
+extern "C" {
+#include "main/compiler.h"
+#include "main/mtypes.h"
+#include "program/prog_parameter.h"
+#include "program/program.h"
+}
+
+static unsigned
+get_deref_name_offset(nir_deref_var *deref_var,
+                      gl_shader_program *shader_program, char **name,
+                      void *mem_ctx)
+{
+   nir_deref *deref = &deref_var->deref;
+   nir_deref_array *deref_array;
+   nir_deref_struct *deref_struct;
+
+   *name = ralloc_strdup(mem_ctx, deref_var->var->name);
+
+   while (deref->child != NULL) {
+      deref = deref->child;
+      switch (deref->deref_type) {
+         case nir_deref_type_array:
+            deref_array = nir_deref_as_array(deref);
+            if (deref_array->has_indirect) {
+               /* GLSL 1.10 and 1.20 allowed variable sampler array indices,
+                * while GLSL 1.30 requires that the array indices be
+                * constant integer expressions.  We don't expect any driver
+                * to actually work with a really variable array index, so
+                * all that would work would be an unrolled loop counter that
+                * ends up being constant.
+                */
+               ralloc_strcat(&shader_program->InfoLog,
+                           "warning: Variable sampler array index unsupported.\n"
+                           "This feature of the language was removed in GLSL 1.20 "
+                           "and is unlikely to be supported for 1.10 in Mesa.\n");
+            }
+            if (deref->child == NULL) {
+               return deref_array->base_offset;
+            }
+            ralloc_asprintf_append(name, "[%u]", deref_array->base_offset);
+            break;
+
+         case nir_deref_type_struct:
+            deref_struct = nir_deref_as_struct(deref);
+            ralloc_asprintf_append(name, ".%s", deref_struct->elem);
+            break;
+
+         default:
+            assert(0);
+            break;
+      }
+   }
+
+   return 0;
+}
+
+static unsigned
+get_sampler_index(nir_deref_var *sampler,
+                  struct gl_shader_program *shader_program,
+                  const struct gl_program *prog)
+{
+   void *mem_ctx = ralloc_context(NULL);
+   char *name;
+   unsigned offset = get_deref_name_offset(sampler, shader_program, &name,
+                                           mem_ctx);
+
+   GLuint shader = _mesa_program_enum_to_shader_stage(prog->Target);
+
+   unsigned location;
+   if (!shader_program->UniformHash->get(location, name)) {
+      linker_error(shader_program,
+                   "failed to find sampler named %s.\n", name);
+      return 0;
+   }
+
+   if (!shader_program->UniformStorage[location].sampler[shader].active) {
+      assert(0 && "cannot return a sampler");
+      linker_error(shader_program,
+                   "cannot return a sampler named %s, because it is not "
+                   "used in this shader stage. This is a driver bug.\n",
+                   name);
+      return 0;
+   }
+
+   ralloc_free(mem_ctx);
+
+   return shader_program->UniformStorage[location].sampler[shader].index +
+          offset;
+}
+
+static void
+lower_sampler(nir_tex_instr *instr, struct gl_shader_program *shader_program,
+              const struct gl_program *prog)
+{
+   if (instr->sampler) {
+      instr->sampler_index = get_sampler_index(instr->sampler, shader_program,
+                                             prog);
+      instr->sampler = NULL;
+   }
+}
+
+typedef struct {
+   struct gl_shader_program *shader_program;
+   struct gl_program *prog;
+} lower_state;
+
+static bool
+lower_block_cb(nir_block *block, void *_state)
+{
+   lower_state *state = (lower_state *) _state;
+
+   nir_foreach_instr(block, instr) {
+      if (instr->type == nir_instr_type_texture) {
+         nir_tex_instr *tex_instr = nir_instr_as_texture(instr);
+         lower_sampler(tex_instr, state->shader_program, state->prog);
+      }
+   }
+
+   return true;
+}
+
+static void
+lower_impl(nir_function_impl *impl, struct gl_shader_program *shader_program,
+           struct gl_program *prog)
+{
+   lower_state state;
+   state.shader_program = shader_program;
+   state.prog = prog;
+   nir_foreach_block(impl, lower_block_cb, &state);
+}
+
+extern "C" void
+nir_lower_samplers(nir_shader *shader, struct gl_shader_program *shader_program,
+                   struct gl_program *prog)
+{
+   nir_foreach_overload(shader, overload) {
+      if (overload->impl)
+         lower_impl(overload->impl, shader_program, prog);
+   }
+}