nir: rename nir_lower_samplers.c{pp,}

With the only C++ function having its own wrapper we can 'demote' this
file to a normal C one. This allows us to get rid of extern C { #include
<foo.h> } 'hacks'. Plus some of the headers may use C99 initializers,
which are not supported by the ISO standard.

This may cause build issue on incremental builds. If so run the
following:

sed -i -e 's|samplers\.cpp|samplers.c|' src/glsl/nir/.deps/nir_lower_samplers.Plo

Fixes: ef8eebc6ad5(nir: support indirect indexing samplers in struct arrays)
Signed-off-by: Emil Velikov <[email protected]>
Reported-by: Gottfried Haider <[email protected]>
Tested-by: Gottfried Haider <[email protected]>
Reviewed-by: Timothy Arceri <[email protected]>

1 files changed, 188 insertions, 0 deletions

diff --git a/src/glsl/nir/nir_lower_samplers.c b/src/glsl/nir/nir_lower_samplers.c
new file mode 100644
index 00000000000..58ea0db4e0f
--- /dev/null
+++ b/src/glsl/nir/nir_lower_samplers.c
@@ -0,0 +1,188 @@
+/*
+ * 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 "nir_builder.h"
+#include "../program.h"
+#include "program/hash_table.h"
+#include "ir_uniform.h"
+
+#include "main/compiler.h"
+#include "main/mtypes.h"
+#include "program/prog_parameter.h"
+#include "program/program.h"
+
+/* Calculate the sampler index based on array indicies and also
+ * calculate the base uniform location for struct members.
+ */
+static void
+calc_sampler_offsets(nir_deref *tail, nir_tex_instr *instr,
+                     unsigned *array_elements, nir_ssa_def **indirect,
+                     nir_builder *b, unsigned *location)
+{
+   if (tail->child == NULL)
+      return;
+
+   switch (tail->child->deref_type) {
+   case nir_deref_type_array: {
+      nir_deref_array *deref_array = nir_deref_as_array(tail->child);
+
+      assert(deref_array->deref_array_type != nir_deref_array_type_wildcard);
+
+      calc_sampler_offsets(tail->child, instr, array_elements,
+                           indirect, b, location);
+      instr->sampler_index += deref_array->base_offset * *array_elements;
+
+      if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
+         nir_ssa_def *mul =
+            nir_imul(b, nir_imm_int(b, *array_elements),
+                     nir_ssa_for_src(b, deref_array->indirect, 1));
+
+         nir_instr_rewrite_src(&instr->instr, &deref_array->indirect,
+                               NIR_SRC_INIT);
+
+         if (*indirect) {
+            *indirect = nir_iadd(b, *indirect, mul);
+         } else {
+            *indirect = mul;
+         }
+      }
+
+      *array_elements *= glsl_get_length(tail->type);
+       break;
+   }
+
+   case nir_deref_type_struct: {
+      nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
+      *location += glsl_get_record_location_offset(tail->type, deref_struct->index);
+      calc_sampler_offsets(tail->child, instr, array_elements,
+                           indirect, b, location);
+      break;
+   }
+
+   default:
+      unreachable("Invalid deref type");
+      break;
+   }
+}
+
+static void
+lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_program,
+              gl_shader_stage stage, nir_builder *builder)
+{
+   if (instr->sampler == NULL)
+      return;
+
+   instr->sampler_index = 0;
+   unsigned location = instr->sampler->var->data.location;
+   unsigned array_elements = 1;
+   nir_ssa_def *indirect = NULL;
+
+   builder->cursor = nir_before_instr(&instr->instr);
+   calc_sampler_offsets(&instr->sampler->deref, instr, &array_elements,
+                        &indirect, builder, &location);
+
+   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);
+
+      for (unsigned i = 0; i < instr->num_srcs; i++) {
+         new_srcs[i].src_type = instr->src[i].src_type;
+         nir_instr_move_src(&instr->instr, &new_srcs[i].src,
+                            &instr->src[i].src);
+      }
+
+      ralloc_free(instr->src);
+      instr->src = new_srcs;
+
+      /* Now we can go ahead and move the source over to being a
+       * first-class texture source.
+       */
+      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->sampler_array_size = array_elements;
+   }
+
+   if (location > shader_program->NumUniformStorage - 1 ||
+       !shader_program->UniformStorage[location].sampler[stage].active) {
+      assert(!"cannot return a sampler");
+      return;
+   }
+
+   instr->sampler_index +=
+      shader_program->UniformStorage[location].sampler[stage].index;
+
+   instr->sampler = NULL;
+}
+
+typedef struct {
+   nir_builder builder;
+   const struct gl_shader_program *shader_program;
+   gl_shader_stage stage;
+} 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_tex) {
+         nir_tex_instr *tex_instr = nir_instr_as_tex(instr);
+         lower_sampler(tex_instr, state->shader_program, state->stage,
+                       &state->builder);
+      }
+   }
+
+   return true;
+}
+
+static void
+lower_impl(nir_function_impl *impl, const struct gl_shader_program *shader_program,
+           gl_shader_stage stage)
+{
+   lower_state state;
+
+   nir_builder_init(&state.builder, impl);
+   state.shader_program = shader_program;
+   state.stage = stage;
+
+   nir_foreach_block(impl, lower_block_cb, &state);
+}
+
+void
+nir_lower_samplers(nir_shader *shader,
+                   const struct gl_shader_program *shader_program)
+{
+   nir_foreach_overload(shader, overload) {
+      if (overload->impl)
+         lower_impl(overload->impl, shader_program, shader->stage);
+   }
+}