glsl: move to compiler/

Signed-off-by: Emil Velikov <[email protected]>
Acked-by: Matt Turner <[email protected]>
Acked-by: Jose Fonseca <[email protected]>

1 files changed, 0 insertions, 1888 deletions

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
deleted file mode 100644
index 264b69ca619..00000000000
--- a/src/glsl/link_varyings.cpp
+++ /dev/null
@@ -1,1888 +0,0 @@
-/*
- * Copyright © 2012 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.
- */
-
-/**
- * \file link_varyings.cpp
- *
- * Linker functions related specifically to linking varyings between shader
- * stages.
- */
-
-
-#include "main/mtypes.h"
-#include "glsl_symbol_table.h"
-#include "glsl_parser_extras.h"
-#include "ir_optimization.h"
-#include "linker.h"
-#include "link_varyings.h"
-#include "main/macros.h"
-#include "program/hash_table.h"
-#include "program.h"
-
-
-/**
- * Get the varying type stripped of the outermost array if we're processing
- * a stage whose varyings are arrays indexed by a vertex number (such as
- * geometry shader inputs).
- */
-static const glsl_type *
-get_varying_type(const ir_variable *var, gl_shader_stage stage)
-{
-   const glsl_type *type = var->type;
-
-   if (!var->data.patch &&
-       ((var->data.mode == ir_var_shader_out &&
-         stage == MESA_SHADER_TESS_CTRL) ||
-        (var->data.mode == ir_var_shader_in &&
-         (stage == MESA_SHADER_TESS_CTRL || stage == MESA_SHADER_TESS_EVAL ||
-          stage == MESA_SHADER_GEOMETRY)))) {
-      assert(type->is_array());
-      type = type->fields.array;
-   }
-
-   return type;
-}
-
-/**
- * Validate the types and qualifiers of an output from one stage against the
- * matching input to another stage.
- */
-static void
-cross_validate_types_and_qualifiers(struct gl_shader_program *prog,
-                                    const ir_variable *input,
-                                    const ir_variable *output,
-                                    gl_shader_stage consumer_stage,
-                                    gl_shader_stage producer_stage)
-{
-   /* Check that the types match between stages.
-    */
-   const glsl_type *type_to_match = input->type;
-
-   /* VS -> GS, VS -> TCS, VS -> TES, TES -> GS */
-   const bool extra_array_level = (producer_stage == MESA_SHADER_VERTEX &&
-                                   consumer_stage != MESA_SHADER_FRAGMENT) ||
-                                  consumer_stage == MESA_SHADER_GEOMETRY;
-   if (extra_array_level) {
-      assert(type_to_match->is_array());
-      type_to_match = type_to_match->fields.array;
-   }
-
-   if (type_to_match != output->type) {
-      /* There is a bit of a special case for gl_TexCoord.  This
-       * built-in is unsized by default.  Applications that variable
-       * access it must redeclare it with a size.  There is some
-       * language in the GLSL spec that implies the fragment shader
-       * and vertex shader do not have to agree on this size.  Other
-       * driver behave this way, and one or two applications seem to
-       * rely on it.
-       *
-       * Neither declaration needs to be modified here because the array
-       * sizes are fixed later when update_array_sizes is called.
-       *
-       * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
-       *
-       *     "Unlike user-defined varying variables, the built-in
-       *     varying variables don't have a strict one-to-one
-       *     correspondence between the vertex language and the
-       *     fragment language."
-       */
-      if (!output->type->is_array() || !is_gl_identifier(output->name)) {
-         linker_error(prog,
-                      "%s shader output `%s' declared as type `%s', "
-                      "but %s shader input declared as type `%s'\n",
-                      _mesa_shader_stage_to_string(producer_stage),
-                      output->name,
-                      output->type->name,
-                      _mesa_shader_stage_to_string(consumer_stage),
-                      input->type->name);
-         return;
-      }
-   }
-
-   /* Check that all of the qualifiers match between stages.
-    */
-   if (input->data.centroid != output->data.centroid) {
-      linker_error(prog,
-                   "%s shader output `%s' %s centroid qualifier, "
-                   "but %s shader input %s centroid qualifier\n",
-                   _mesa_shader_stage_to_string(producer_stage),
-                   output->name,
-                   (output->data.centroid) ? "has" : "lacks",
-                   _mesa_shader_stage_to_string(consumer_stage),
-                   (input->data.centroid) ? "has" : "lacks");
-      return;
-   }
-
-   if (input->data.sample != output->data.sample) {
-      linker_error(prog,
-                   "%s shader output `%s' %s sample qualifier, "
-                   "but %s shader input %s sample qualifier\n",
-                   _mesa_shader_stage_to_string(producer_stage),
-                   output->name,
-                   (output->data.sample) ? "has" : "lacks",
-                   _mesa_shader_stage_to_string(consumer_stage),
-                   (input->data.sample) ? "has" : "lacks");
-      return;
-   }
-
-   if (input->data.patch != output->data.patch) {
-      linker_error(prog,
-                   "%s shader output `%s' %s patch qualifier, "
-                   "but %s shader input %s patch qualifier\n",
-                   _mesa_shader_stage_to_string(producer_stage),
-                   output->name,
-                   (output->data.patch) ? "has" : "lacks",
-                   _mesa_shader_stage_to_string(consumer_stage),
-                   (input->data.patch) ? "has" : "lacks");
-      return;
-   }
-
-   if (!prog->IsES && input->data.invariant != output->data.invariant) {
-      linker_error(prog,
-                   "%s shader output `%s' %s invariant qualifier, "
-                   "but %s shader input %s invariant qualifier\n",
-                   _mesa_shader_stage_to_string(producer_stage),
-                   output->name,
-                   (output->data.invariant) ? "has" : "lacks",
-                   _mesa_shader_stage_to_string(consumer_stage),
-                   (input->data.invariant) ? "has" : "lacks");
-      return;
-   }
-
-   /* GLSL >= 4.40 removes text requiring interpolation qualifiers
-    * to match cross stage, they must only match within the same stage.
-    *
-    * From page 84 (page 90 of the PDF) of the GLSL 4.40 spec:
-    *
-    *     "It is a link-time error if, within the same stage, the interpolation
-    *     qualifiers of variables of the same name do not match.
-    *
-    */
-   if (input->data.interpolation != output->data.interpolation &&
-       prog->Version < 440) {
-      linker_error(prog,
-                   "%s shader output `%s' specifies %s "
-                   "interpolation qualifier, "
-                   "but %s shader input specifies %s "
-                   "interpolation qualifier\n",
-                   _mesa_shader_stage_to_string(producer_stage),
-                   output->name,
-                   interpolation_string(output->data.interpolation),
-                   _mesa_shader_stage_to_string(consumer_stage),
-                   interpolation_string(input->data.interpolation));
-      return;
-   }
-}
-
-/**
- * Validate front and back color outputs against single color input
- */
-static void
-cross_validate_front_and_back_color(struct gl_shader_program *prog,
-                                    const ir_variable *input,
-                                    const ir_variable *front_color,
-                                    const ir_variable *back_color,
-                                    gl_shader_stage consumer_stage,
-                                    gl_shader_stage producer_stage)
-{
-   if (front_color != NULL && front_color->data.assigned)
-      cross_validate_types_and_qualifiers(prog, input, front_color,
-                                          consumer_stage, producer_stage);
-
-   if (back_color != NULL && back_color->data.assigned)
-      cross_validate_types_and_qualifiers(prog, input, back_color,
-                                          consumer_stage, producer_stage);
-}
-
-/**
- * Validate that outputs from one stage match inputs of another
- */
-void
-cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
-				 gl_shader *producer, gl_shader *consumer)
-{
-   glsl_symbol_table parameters;
-   ir_variable *explicit_locations[MAX_VARYING] = { NULL, };
-
-   /* Find all shader outputs in the "producer" stage.
-    */
-   foreach_in_list(ir_instruction, node, producer->ir) {
-      ir_variable *const var = node->as_variable();
-
-      if ((var == NULL) || (var->data.mode != ir_var_shader_out))
-	 continue;
-
-      if (!var->data.explicit_location
-          || var->data.location < VARYING_SLOT_VAR0)
-         parameters.add_variable(var);
-      else {
-         /* User-defined varyings with explicit locations are handled
-          * differently because they do not need to have matching names.
-          */
-         const unsigned idx = var->data.location - VARYING_SLOT_VAR0;
-
-         if (explicit_locations[idx] != NULL) {
-            linker_error(prog,
-                         "%s shader has multiple outputs explicitly "
-                         "assigned to location %d\n",
-                         _mesa_shader_stage_to_string(producer->Stage),
-                         idx);
-            return;
-         }
-
-         explicit_locations[idx] = var;
-      }
-   }
-
-
-   /* Find all shader inputs in the "consumer" stage.  Any variables that have
-    * matching outputs already in the symbol table must have the same type and
-    * qualifiers.
-    *
-    * Exception: if the consumer is the geometry shader, then the inputs
-    * should be arrays and the type of the array element should match the type
-    * of the corresponding producer output.
-    */
-   foreach_in_list(ir_instruction, node, consumer->ir) {
-      ir_variable *const input = node->as_variable();
-
-      if ((input == NULL) || (input->data.mode != ir_var_shader_in))
-	 continue;
-
-      if (strcmp(input->name, "gl_Color") == 0 && input->data.used) {
-         const ir_variable *const front_color =
-            parameters.get_variable("gl_FrontColor");
-
-         const ir_variable *const back_color =
-            parameters.get_variable("gl_BackColor");
-
-         cross_validate_front_and_back_color(prog, input,
-                                             front_color, back_color,
-                                             consumer->Stage, producer->Stage);
-      } else if (strcmp(input->name, "gl_SecondaryColor") == 0 && input->data.used) {
-         const ir_variable *const front_color =
-            parameters.get_variable("gl_FrontSecondaryColor");
-
-         const ir_variable *const back_color =
-            parameters.get_variable("gl_BackSecondaryColor");
-
-         cross_validate_front_and_back_color(prog, input,
-                                             front_color, back_color,
-                                             consumer->Stage, producer->Stage);
-      } else {
-         /* The rules for connecting inputs and outputs change in the presence
-          * of explicit locations.  In this case, we no longer care about the
-          * names of the variables.  Instead, we care only about the
-          * explicitly assigned location.
-          */
-         ir_variable *output = NULL;
-         if (input->data.explicit_location
-             && input->data.location >= VARYING_SLOT_VAR0) {
-            output = explicit_locations[input->data.location - VARYING_SLOT_VAR0];
-
-            if (output == NULL) {
-               linker_error(prog,
-                            "%s shader input `%s' with explicit location "
-                            "has no matching output\n",
-                            _mesa_shader_stage_to_string(consumer->Stage),
-                            input->name);
-            }
-         } else {
-            output = parameters.get_variable(input->name);
-         }
-
-         if (output != NULL) {
-            cross_validate_types_and_qualifiers(prog, input, output,
-                                                consumer->Stage, producer->Stage);
-         } else {
-            /* Check for input vars with unmatched output vars in prev stage
-             * taking into account that interface blocks could have a matching
-             * output but with different name, so we ignore them.
-             */
-            assert(!input->data.assigned);
-            if (input->data.used && !input->get_interface_type() &&
-                !input->data.explicit_location && !prog->SeparateShader)
-               linker_error(prog,
-                            "%s shader input `%s' "
-                            "has no matching output in the previous stage\n",
-                            _mesa_shader_stage_to_string(consumer->Stage),
-                            input->name);
-         }
-      }
-   }
-}
-
-/**
- * Demote shader inputs and outputs that are not used in other stages, and
- * remove them via dead code elimination.
- */
-void
-remove_unused_shader_inputs_and_outputs(bool is_separate_shader_object,
-                                        gl_shader *sh,
-                                        enum ir_variable_mode mode)
-{
-   if (is_separate_shader_object)
-      return;
-
-   foreach_in_list(ir_instruction, node, sh->ir) {
-      ir_variable *const var = node->as_variable();
-
-      if ((var == NULL) || (var->data.mode != int(mode)))
-	 continue;
-
-      /* A shader 'in' or 'out' variable is only really an input or output if
-       * its value is used by other shader stages. This will cause the
-       * variable to have a location assigned.
-       */
-      if (var->data.is_unmatched_generic_inout) {
-         assert(var->data.mode != ir_var_temporary);
-	 var->data.mode = ir_var_auto;
-      }
-   }
-
-   /* Eliminate code that is now dead due to unused inputs/outputs being
-    * demoted.
-    */
-   while (do_dead_code(sh->ir, false))
-      ;
-
-}
-
-/**
- * Initialize this object based on a string that was passed to
- * glTransformFeedbackVaryings.
- *
- * If the input is mal-formed, this call still succeeds, but it sets
- * this->var_name to a mal-formed input, so tfeedback_decl::find_output_var()
- * will fail to find any matching variable.
- */
-void
-tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx,
-                     const char *input)
-{
-   /* We don't have to be pedantic about what is a valid GLSL variable name,
-    * because any variable with an invalid name can't exist in the IR anyway.
-    */
-
-   this->location = -1;
-   this->orig_name = input;
-   this->lowered_builtin_array_variable = none;
-   this->skip_components = 0;
-   this->next_buffer_separator = false;
-   this->matched_candidate = NULL;
-   this->stream_id = 0;
-
-   if (ctx->Extensions.ARB_transform_feedback3) {
-      /* Parse gl_NextBuffer. */
-      if (strcmp(input, "gl_NextBuffer") == 0) {
-         this->next_buffer_separator = true;
-         return;
-      }
-
-      /* Parse gl_SkipComponents. */
-      if (strcmp(input, "gl_SkipComponents1") == 0)
-         this->skip_components = 1;
-      else if (strcmp(input, "gl_SkipComponents2") == 0)
-         this->skip_components = 2;
-      else if (strcmp(input, "gl_SkipComponents3") == 0)
-         this->skip_components = 3;
-      else if (strcmp(input, "gl_SkipComponents4") == 0)
-         this->skip_components = 4;
-
-      if (this->skip_components)
-         return;
-   }
-
-   /* Parse a declaration. */
-   const char *base_name_end;
-   long subscript = parse_program_resource_name(input, &base_name_end);
-   this->var_name = ralloc_strndup(mem_ctx, input, base_name_end - input);
-   if (this->var_name == NULL) {
-      _mesa_error_no_memory(__func__);
-      return;
-   }
-
-   if (subscript >= 0) {
-      this->array_subscript = subscript;
-      this->is_subscripted = true;
-   } else {
-      this->is_subscripted = false;
-   }
-
-   /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this
-    * class must behave specially to account for the fact that gl_ClipDistance
-    * is converted from a float[8] to a vec4[2].
-    */
-   if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
-       strcmp(this->var_name, "gl_ClipDistance") == 0) {
-      this->lowered_builtin_array_variable = clip_distance;
-   }
-
-   if (ctx->Const.LowerTessLevel &&
-       (strcmp(this->var_name, "gl_TessLevelOuter") == 0))
-      this->lowered_builtin_array_variable = tess_level_outer;
-   if (ctx->Const.LowerTessLevel &&
-       (strcmp(this->var_name, "gl_TessLevelInner") == 0))
-      this->lowered_builtin_array_variable = tess_level_inner;
-}
-
-
-/**
- * Determine whether two tfeedback_decl objects refer to the same variable and
- * array index (if applicable).
- */
-bool
-tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y)
-{
-   assert(x.is_varying() && y.is_varying());
-
-   if (strcmp(x.var_name, y.var_name) != 0)
-      return false;
-   if (x.is_subscripted != y.is_subscripted)
-      return false;
-   if (x.is_subscripted && x.array_subscript != y.array_subscript)
-      return false;
-   return true;
-}
-
-
-/**
- * Assign a location and stream ID for this tfeedback_decl object based on the
- * transform feedback candidate found by find_candidate.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::assign_location(struct gl_context *ctx,
-                                struct gl_shader_program *prog)
-{
-   assert(this->is_varying());
-
-   unsigned fine_location
-      = this->matched_candidate->toplevel_var->data.location * 4
-      + this->matched_candidate->toplevel_var->data.location_frac
-      + this->matched_candidate->offset;
-
-   if (this->matched_candidate->type->is_array()) {
-      /* Array variable */
-      const unsigned matrix_cols =
-         this->matched_candidate->type->fields.array->matrix_columns;
-      const unsigned vector_elements =
-         this->matched_candidate->type->fields.array->vector_elements;
-      const unsigned dmul =
-         this->matched_candidate->type->fields.array->is_double() ? 2 : 1;
-      unsigned actual_array_size;
-      switch (this->lowered_builtin_array_variable) {
-      case clip_distance:
-         actual_array_size = prog->LastClipDistanceArraySize;
-         break;
-      case tess_level_outer:
-         actual_array_size = 4;
-         break;
-      case tess_level_inner:
-         actual_array_size = 2;
-         break;
-      case none:
-      default:
-         actual_array_size = this->matched_candidate->type->array_size();
-         break;
-      }
-
-      if (this->is_subscripted) {
-         /* Check array bounds. */
-         if (this->array_subscript >= actual_array_size) {
-            linker_error(prog, "Transform feedback varying %s has index "
-                         "%i, but the array size is %u.",
-                         this->orig_name, this->array_subscript,
-                         actual_array_size);
-            return false;
-         }
-         unsigned array_elem_size = this->lowered_builtin_array_variable ?
-            1 : vector_elements * matrix_cols * dmul;
-         fine_location += array_elem_size * this->array_subscript;
-         this->size = 1;
-      } else {
-         this->size = actual_array_size;
-      }
-      this->vector_elements = vector_elements;
-      this->matrix_columns = matrix_cols;
-      if (this->lowered_builtin_array_variable)
-         this->type = GL_FLOAT;
-      else
-         this->type = this->matched_candidate->type->fields.array->gl_type;
-   } else {
-      /* Regular variable (scalar, vector, or matrix) */
-      if (this->is_subscripted) {
-         linker_error(prog, "Transform feedback varying %s requested, "
-                      "but %s is not an array.",
-                      this->orig_name, this->var_name);
-         return false;
-      }
-      this->size = 1;
-      this->vector_elements = this->matched_candidate->type->vector_elements;
-      this->matrix_columns = this->matched_candidate->type->matrix_columns;
-      this->type = this->matched_candidate->type->gl_type;
-   }
-   this->location = fine_location / 4;
-   this->location_frac = fine_location % 4;
-
-   /* From GL_EXT_transform_feedback:
-    *   A program will fail to link if:
-    *
-    *   * the total number of components to capture in any varying
-    *     variable in <varyings> is greater than the constant
-    *     MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
-    *     buffer mode is SEPARATE_ATTRIBS_EXT;
-    */
-   if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
-       this->num_components() >
-       ctx->Const.MaxTransformFeedbackSeparateComponents) {
-      linker_error(prog, "Transform feedback varying %s exceeds "
-                   "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
-                   this->orig_name);
-      return false;
-   }
-
-   /* Only transform feedback varyings can be assigned to non-zero streams,
-    * so assign the stream id here.
-    */
-   this->stream_id = this->matched_candidate->toplevel_var->data.stream;
-
-   return true;
-}
-
-
-unsigned
-tfeedback_decl::get_num_outputs() const
-{
-   if (!this->is_varying()) {
-      return 0;
-   }
-   return (this->num_components() + this->location_frac + 3)/4;
-}
-
-
-/**
- * Update gl_transform_feedback_info to reflect this tfeedback_decl.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog,
-                      struct gl_transform_feedback_info *info,
-                      unsigned buffer, const unsigned max_outputs) const
-{
-   assert(!this->next_buffer_separator);
-
-   /* Handle gl_SkipComponents. */
-   if (this->skip_components) {
-      info->BufferStride[buffer] += this->skip_components;
-      return true;
-   }
-
-   /* From GL_EXT_transform_feedback:
-    *   A program will fail to link if:
-    *
-    *     * the total number of components to capture is greater than
-    *       the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT
-    *       and the buffer mode is INTERLEAVED_ATTRIBS_EXT.
-    */
-   if (prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS &&
-       info->BufferStride[buffer] + this->num_components() >
-       ctx->Const.MaxTransformFeedbackInterleavedComponents) {
-      linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
-                   "limit has been exceeded.");
-      return false;
-   }
-
-   unsigned location = this->location;
-   unsigned location_frac = this->location_frac;
-   unsigned num_components = this->num_components();
-   while (num_components > 0) {
-      unsigned output_size = MIN2(num_components, 4 - location_frac);
-      assert(info->NumOutputs < max_outputs);
-      info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
-      info->Outputs[info->NumOutputs].OutputRegister = location;
-      info->Outputs[info->NumOutputs].NumComponents = output_size;
-      info->Outputs[info->NumOutputs].StreamId = stream_id;
-      info->Outputs[info->NumOutputs].OutputBuffer = buffer;
-      info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer];
-      ++info->NumOutputs;
-      info->BufferStride[buffer] += output_size;
-      info->BufferStream[buffer] = this->stream_id;
-      num_components -= output_size;
-      location++;
-      location_frac = 0;
-   }
-
-   info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name);
-   info->Varyings[info->NumVarying].Type = this->type;
-   info->Varyings[info->NumVarying].Size = this->size;
-   info->NumVarying++;
-
-   return true;
-}
-
-
-const tfeedback_candidate *
-tfeedback_decl::find_candidate(gl_shader_program *prog,
-                               hash_table *tfeedback_candidates)
-{
-   const char *name = this->var_name;
-   switch (this->lowered_builtin_array_variable) {
-   case none:
-      name = this->var_name;
-      break;
-   case clip_distance:
-      name = "gl_ClipDistanceMESA";
-      break;
-   case tess_level_outer:
-      name = "gl_TessLevelOuterMESA";
-      break;
-   case tess_level_inner:
-      name = "gl_TessLevelInnerMESA";
-      break;
-   }
-   this->matched_candidate = (const tfeedback_candidate *)
-      hash_table_find(tfeedback_candidates, name);
-   if (!this->matched_candidate) {
-      /* From GL_EXT_transform_feedback:
-       *   A program will fail to link if:
-       *
-       *   * any variable name specified in the <varyings> array is not
-       *     declared as an output in the geometry shader (if present) or
-       *     the vertex shader (if no geometry shader is present);
-       */
-      linker_error(prog, "Transform feedback varying %s undeclared.",
-                   this->orig_name);
-   }
-   return this->matched_candidate;
-}
-
-
-/**
- * Parse all the transform feedback declarations that were passed to
- * glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
-                      const void *mem_ctx, unsigned num_names,
-                      char **varying_names, tfeedback_decl *decls)
-{
-   for (unsigned i = 0; i < num_names; ++i) {
-      decls[i].init(ctx, mem_ctx, varying_names[i]);
-
-      if (!decls[i].is_varying())
-         continue;
-
-      /* From GL_EXT_transform_feedback:
-       *   A program will fail to link if:
-       *
-       *   * any two entries in the <varyings> array specify the same varying
-       *     variable;
-       *
-       * We interpret this to mean "any two entries in the <varyings> array
-       * specify the same varying variable and array index", since transform
-       * feedback of arrays would be useless otherwise.
-       */
-      for (unsigned j = 0; j < i; ++j) {
-         if (!decls[j].is_varying())
-            continue;
-
-         if (tfeedback_decl::is_same(decls[i], decls[j])) {
-            linker_error(prog, "Transform feedback varying %s specified "
-                         "more than once.", varying_names[i]);
-            return false;
-         }
-      }
-   }
-   return true;
-}
-
-
-/**
- * Store transform feedback location assignments into
- * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
-                     unsigned num_tfeedback_decls,
-                     tfeedback_decl *tfeedback_decls)
-{
-   bool separate_attribs_mode =
-      prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
-
-   ralloc_free(prog->LinkedTransformFeedback.Varyings);
-   ralloc_free(prog->LinkedTransformFeedback.Outputs);
-
-   memset(&prog->LinkedTransformFeedback, 0,
-          sizeof(prog->LinkedTransformFeedback));
-
-   prog->LinkedTransformFeedback.Varyings =
-      rzalloc_array(prog,
-		    struct gl_transform_feedback_varying_info,
-		    num_tfeedback_decls);
-
-   unsigned num_outputs = 0;
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i)
-      num_outputs += tfeedback_decls[i].get_num_outputs();
-
-   prog->LinkedTransformFeedback.Outputs =
-      rzalloc_array(prog,
-                    struct gl_transform_feedback_output,
-                    num_outputs);
-
-   unsigned num_buffers = 0;
-
-   if (separate_attribs_mode) {
-      /* GL_SEPARATE_ATTRIBS */
-      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-         if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback,
-                                       num_buffers, num_outputs))
-            return false;
-
-         num_buffers++;
-      }
-   }
-   else {
-      /* GL_INVERLEAVED_ATTRIBS */
-      int buffer_stream_id = -1;
-      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-         if (tfeedback_decls[i].is_next_buffer_separator()) {
-            num_buffers++;
-            buffer_stream_id = -1;
-            continue;
-         } else if (buffer_stream_id == -1)  {
-            /* First varying writing to this buffer: remember its stream */
-            buffer_stream_id = (int) tfeedback_decls[i].get_stream_id();
-         } else if (buffer_stream_id !=
-                    (int) tfeedback_decls[i].get_stream_id()) {
-            /* Varying writes to the same buffer from a different stream */
-            linker_error(prog,
-                         "Transform feedback can't capture varyings belonging "
-                         "to different vertex streams in a single buffer. "
-                         "Varying %s writes to buffer from stream %u, other "
-                         "varyings in the same buffer write from stream %u.",
-                         tfeedback_decls[i].name(),
-                         tfeedback_decls[i].get_stream_id(),
-                         buffer_stream_id);
-            return false;
-         }
-
-         if (!tfeedback_decls[i].store(ctx, prog,
-                                       &prog->LinkedTransformFeedback,
-                                       num_buffers, num_outputs))
-            return false;
-      }
-      num_buffers++;
-   }
-
-   assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs);
-
-   prog->LinkedTransformFeedback.NumBuffers = num_buffers;
-   return true;
-}
-
-namespace {
-
-/**
- * Data structure recording the relationship between outputs of one shader
- * stage (the "producer") and inputs of another (the "consumer").
- */
-class varying_matches
-{
-public:
-   varying_matches(bool disable_varying_packing,
-                   gl_shader_stage producer_stage,
-                   gl_shader_stage consumer_stage);
-   ~varying_matches();
-   void record(ir_variable *producer_var, ir_variable *consumer_var);
-   unsigned assign_locations(struct gl_shader_program *prog,
-                             uint64_t reserved_slots, bool separate_shader);
-   void store_locations() const;
-
-private:
-   /**
-    * If true, this driver disables varying packing, so all varyings need to
-    * be aligned on slot boundaries, and take up a number of slots equal to
-    * their number of matrix columns times their array size.
-    */
-   const bool disable_varying_packing;
-
-   /**
-    * Enum representing the order in which varyings are packed within a
-    * packing class.
-    *
-    * Currently we pack vec4's first, then vec2's, then scalar values, then
-    * vec3's.  This order ensures that the only vectors that are at risk of
-    * having to be "double parked" (split between two adjacent varying slots)
-    * are the vec3's.
-    */
-   enum packing_order_enum {
-      PACKING_ORDER_VEC4,
-      PACKING_ORDER_VEC2,
-      PACKING_ORDER_SCALAR,
-      PACKING_ORDER_VEC3,
-   };
-
-   static unsigned compute_packing_class(const ir_variable *var);
-   static packing_order_enum compute_packing_order(const ir_variable *var);
-   static int match_comparator(const void *x_generic, const void *y_generic);
-
-   /**
-    * Structure recording the relationship between a single producer output
-    * and a single consumer input.
-    */
-   struct match {
-      /**
-       * Packing class for this varying, computed by compute_packing_class().
-       */
-      unsigned packing_class;
-
-      /**
-       * Packing order for this varying, computed by compute_packing_order().
-       */
-      packing_order_enum packing_order;
-      unsigned num_components;
-
-      /**
-       * The output variable in the producer stage.
-       */
-      ir_variable *producer_var;
-
-      /**
-       * The input variable in the consumer stage.
-       */
-      ir_variable *consumer_var;
-
-      /**
-       * The location which has been assigned for this varying.  This is
-       * expressed in multiples of a float, with the first generic varying
-       * (i.e. the one referred to by VARYING_SLOT_VAR0) represented by the
-       * value 0.
-       */
-      unsigned generic_location;
-   } *matches;
-
-   /**
-    * The number of elements in the \c matches array that are currently in
-    * use.
-    */
-   unsigned num_matches;
-
-   /**
-    * The number of elements that were set aside for the \c matches array when
-    * it was allocated.
-    */
-   unsigned matches_capacity;
-
-   gl_shader_stage producer_stage;
-   gl_shader_stage consumer_stage;
-};
-
-} /* anonymous namespace */
-
-varying_matches::varying_matches(bool disable_varying_packing,
-                                 gl_shader_stage producer_stage,
-                                 gl_shader_stage consumer_stage)
-   : disable_varying_packing(disable_varying_packing),
-     producer_stage(producer_stage),
-     consumer_stage(consumer_stage)
-{
-   /* Note: this initial capacity is rather arbitrarily chosen to be large
-    * enough for many cases without wasting an unreasonable amount of space.
-    * varying_matches::record() will resize the array if there are more than
-    * this number of varyings.
-    */
-   this->matches_capacity = 8;
-   this->matches = (match *)
-      malloc(sizeof(*this->matches) * this->matches_capacity);
-   this->num_matches = 0;
-}
-
-
-varying_matches::~varying_matches()
-{
-   free(this->matches);
-}
-
-
-/**
- * Record the given producer/consumer variable pair in the list of variables
- * that should later be assigned locations.
- *
- * It is permissible for \c consumer_var to be NULL (this happens if a
- * variable is output by the producer and consumed by transform feedback, but
- * not consumed by the consumer).
- *
- * If \c producer_var has already been paired up with a consumer_var, or
- * producer_var is part of fixed pipeline functionality (and hence already has
- * a location assigned), this function has no effect.
- *
- * Note: as a side effect this function may change the interpolation type of
- * \c producer_var, but only when the change couldn't possibly affect
- * rendering.
- */
-void
-varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
-{
-   assert(producer_var != NULL || consumer_var != NULL);
-
-   if ((producer_var && (!producer_var->data.is_unmatched_generic_inout ||
-       producer_var->data.explicit_location)) ||
-       (consumer_var && (!consumer_var->data.is_unmatched_generic_inout ||
-       consumer_var->data.explicit_location))) {
-      /* Either a location already exists for this variable (since it is part
-       * of fixed functionality), or it has already been recorded as part of a
-       * previous match.
-       */
-      return;
-   }
-
-   if ((consumer_var == NULL && producer_var->type->contains_integer()) ||
-       (consumer_stage != -1 && consumer_stage != MESA_SHADER_FRAGMENT)) {
-      /* Since this varying is not being consumed by the fragment shader, its
-       * interpolation type varying cannot possibly affect rendering.
-       * Also, this variable is non-flat and is (or contains) an integer.
-       * If the consumer stage is unknown, don't modify the interpolation
-       * type as it could affect rendering later with separate shaders.
-       *
-       * lower_packed_varyings requires all integer varyings to flat,
-       * regardless of where they appear.  We can trivially satisfy that
-       * requirement by changing the interpolation type to flat here.
-       */
-      if (producer_var) {
-         producer_var->data.centroid = false;
-         producer_var->data.sample = false;
-         producer_var->data.interpolation = INTERP_QUALIFIER_FLAT;
-      }
-
-      if (consumer_var) {
-         consumer_var->data.centroid = false;
-         consumer_var->data.sample = false;
-         consumer_var->data.interpolation = INTERP_QUALIFIER_FLAT;
-      }
-   }
-
-   if (this->num_matches == this->matches_capacity) {
-      this->matches_capacity *= 2;
-      this->matches = (match *)
-         realloc(this->matches,
-                 sizeof(*this->matches) * this->matches_capacity);
-   }
-
-   const ir_variable *const var = (producer_var != NULL)
-      ? producer_var : consumer_var;
-   const gl_shader_stage stage = (producer_var != NULL)
-      ? producer_stage : consumer_stage;
-   const glsl_type *type = get_varying_type(var, stage);
-
-   this->matches[this->num_matches].packing_class
-      = this->compute_packing_class(var);
-   this->matches[this->num_matches].packing_order
-      = this->compute_packing_order(var);
-   if (this->disable_varying_packing) {
-      unsigned slots = type->count_attribute_slots(false);
-      this->matches[this->num_matches].num_components = slots * 4;
-   } else {
-      this->matches[this->num_matches].num_components
-         = type->component_slots();
-   }
-   this->matches[this->num_matches].producer_var = producer_var;
-   this->matches[this->num_matches].consumer_var = consumer_var;
-   this->num_matches++;
-   if (producer_var)
-      producer_var->data.is_unmatched_generic_inout = 0;
-   if (consumer_var)
-      consumer_var->data.is_unmatched_generic_inout = 0;
-}
-
-
-/**
- * Choose locations for all of the variable matches that were previously
- * passed to varying_matches::record().
- */
-unsigned
-varying_matches::assign_locations(struct gl_shader_program *prog,
-                                  uint64_t reserved_slots,
-                                  bool separate_shader)
-{
-   /* We disable varying sorting for separate shader programs for the
-    * following reasons:
-    *
-    * 1/ All programs must sort the code in the same order to guarantee the
-    *    interface matching. However varying_matches::record() will change the
-    *    interpolation qualifier of some stages.
-    *
-    * 2/ GLSL version 4.50 removes the matching constrain on the interpolation
-    *    qualifier.
-    *
-    * From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.40 spec:
-    *
-    *    "The type and presence of interpolation qualifiers of variables with
-    *    the same name declared in all linked shaders for the same cross-stage
-    *    interface must match, otherwise the link command will fail.
-    *
-    *    When comparing an output from one stage to an input of a subsequent
-    *    stage, the input and output don't match if their interpolation
-    *    qualifiers (or lack thereof) are not the same."
-    *
-    *    "It is a link-time error if, within the same stage, the interpolation
-    *    qualifiers of variables of the same name do not match."
-    */
-   if (!separate_shader) {
-      /* Sort varying matches into an order that makes them easy to pack. */
-      qsort(this->matches, this->num_matches, sizeof(*this->matches),
-            &varying_matches::match_comparator);
-   }
-
-   unsigned generic_location = 0;
-   unsigned generic_patch_location = MAX_VARYING*4;
-
-   for (unsigned i = 0; i < this->num_matches; i++) {
-      unsigned *location = &generic_location;
-
-      const ir_variable *var;
-      const glsl_type *type;
-      bool is_vertex_input = false;
-      if (matches[i].consumer_var) {
-         var = matches[i].consumer_var;
-         type = get_varying_type(var, consumer_stage);
-         if (consumer_stage == MESA_SHADER_VERTEX)
-            is_vertex_input = true;
-      } else {
-         var = matches[i].producer_var;
-         type = get_varying_type(var, producer_stage);
-      }
-
-      if (var->data.patch)
-         location = &generic_patch_location;
-
-      /* Advance to the next slot if this varying has a different packing
-       * class than the previous one, and we're not already on a slot
-       * boundary.
-       */
-      if (i > 0 &&
-          this->matches[i - 1].packing_class
-          != this->matches[i].packing_class) {
-         *location = ALIGN(*location, 4);
-      }
-
-      unsigned num_elements =  type->count_attribute_slots(is_vertex_input);
-      unsigned slot_end = this->disable_varying_packing ? 4 :
-         type->without_array()->vector_elements;
-      slot_end += *location - 1;
-
-      /* FIXME: We could be smarter in the below code and loop back over
-       * trying to fill any locations that we skipped because we couldn't pack
-       * the varying between an explicit location. For now just let the user
-       * hit the linking error if we run out of room and suggest they use
-       * explicit locations.
-       */
-      for (unsigned j = 0; j < num_elements; j++) {
-         while ((slot_end < MAX_VARYING * 4u) &&
-                ((reserved_slots & (UINT64_C(1) << *location / 4u) ||
-                 (reserved_slots & (UINT64_C(1) << slot_end / 4u))))) {
-
-            *location = ALIGN(*location + 1, 4);
-            slot_end = *location;
-
-            /* reset the counter and try again */
-            j = 0;
-         }
-
-         /* Increase the slot to make sure there is enough room for next
-          * array element.
-          */
-         if (this->disable_varying_packing)
-            slot_end += 4;
-         else
-            slot_end += type->without_array()->vector_elements;
-      }
-
-      if (!var->data.patch && *location >= MAX_VARYING * 4u) {
-         linker_error(prog, "insufficient contiguous locations available for "
-                      "%s it is possible an array or struct could not be "
-                      "packed between varyings with explicit locations. Try "
-                      "using an explicit location for arrays and structs.",
-                      var->name);
-      }
-
-      this->matches[i].generic_location = *location;
-
-      *location += this->matches[i].num_components;
-   }
-
-   return (generic_location + 3) / 4;
-}
-
-
-/**
- * Update the producer and consumer shaders to reflect the locations
- * assignments that were made by varying_matches::assign_locations().
- */
-void
-varying_matches::store_locations() const
-{
-   for (unsigned i = 0; i < this->num_matches; i++) {
-      ir_variable *producer_var = this->matches[i].producer_var;
-      ir_variable *consumer_var = this->matches[i].consumer_var;
-      unsigned generic_location = this->matches[i].generic_location;
-      unsigned slot = generic_location / 4;
-      unsigned offset = generic_location % 4;
-
-      if (producer_var) {
-         producer_var->data.location = VARYING_SLOT_VAR0 + slot;
-         producer_var->data.location_frac = offset;
-      }
-
-      if (consumer_var) {
-         assert(consumer_var->data.location == -1);
-         consumer_var->data.location = VARYING_SLOT_VAR0 + slot;
-         consumer_var->data.location_frac = offset;
-      }
-   }
-}
-
-
-/**
- * Compute the "packing class" of the given varying.  This is an unsigned
- * integer with the property that two variables in the same packing class can
- * be safely backed into the same vec4.
- */
-unsigned
-varying_matches::compute_packing_class(const ir_variable *var)
-{
-   /* Without help from the back-end, there is no way to pack together
-    * variables with different interpolation types, because
-    * lower_packed_varyings must choose exactly one interpolation type for
-    * each packed varying it creates.
-    *
-    * However, we can safely pack together floats, ints, and uints, because:
-    *
-    * - varyings of base type "int" and "uint" must use the "flat"
-    *   interpolation type, which can only occur in GLSL 1.30 and above.
-    *
-    * - On platforms that support GLSL 1.30 and above, lower_packed_varyings
-    *   can store flat floats as ints without losing any information (using
-    *   the ir_unop_bitcast_* opcodes).
-    *
-    * Therefore, the packing class depends only on the interpolation type.
-    */
-   unsigned packing_class = var->data.centroid | (var->data.sample << 1) |
-                            (var->data.patch << 2);
-   packing_class *= 4;
-   packing_class += var->data.interpolation;
-   return packing_class;
-}
-
-
-/**
- * Compute the "packing order" of the given varying.  This is a sort key we
- * use to determine when to attempt to pack the given varying relative to
- * other varyings in the same packing class.
- */
-varying_matches::packing_order_enum
-varying_matches::compute_packing_order(const ir_variable *var)
-{
-   const glsl_type *element_type = var->type;
-
-   while (element_type->base_type == GLSL_TYPE_ARRAY) {
-      element_type = element_type->fields.array;
-   }
-
-   switch (element_type->component_slots() % 4) {
-   case 1: return PACKING_ORDER_SCALAR;
-   case 2: return PACKING_ORDER_VEC2;
-   case 3: return PACKING_ORDER_VEC3;
-   case 0: return PACKING_ORDER_VEC4;
-   default:
-      assert(!"Unexpected value of vector_elements");
-      return PACKING_ORDER_VEC4;
-   }
-}
-
-
-/**
- * Comparison function passed to qsort() to sort varyings by packing_class and
- * then by packing_order.
- */
-int
-varying_matches::match_comparator(const void *x_generic, const void *y_generic)
-{
-   const match *x = (const match *) x_generic;
-   const match *y = (const match *) y_generic;
-
-   if (x->packing_class != y->packing_class)
-      return x->packing_class - y->packing_class;
-   return x->packing_order - y->packing_order;
-}
-
-
-/**
- * Is the given variable a varying variable to be counted against the
- * limit in ctx->Const.MaxVarying?
- * This includes variables such as texcoords, colors and generic
- * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord.
- */
-static bool
-var_counts_against_varying_limit(gl_shader_stage stage, const ir_variable *var)
-{
-   /* Only fragment shaders will take a varying variable as an input */
-   if (stage == MESA_SHADER_FRAGMENT &&
-       var->data.mode == ir_var_shader_in) {
-      switch (var->data.location) {
-      case VARYING_SLOT_POS:
-      case VARYING_SLOT_FACE:
-      case VARYING_SLOT_PNTC:
-         return false;
-      default:
-         return true;
-      }
-   }
-   return false;
-}
-
-
-/**
- * Visitor class that generates tfeedback_candidate structs describing all
- * possible targets of transform feedback.
- *
- * tfeedback_candidate structs are stored in the hash table
- * tfeedback_candidates, which is passed to the constructor.  This hash table
- * maps varying names to instances of the tfeedback_candidate struct.
- */
-class tfeedback_candidate_generator : public program_resource_visitor
-{
-public:
-   tfeedback_candidate_generator(void *mem_ctx,
-                                 hash_table *tfeedback_candidates)
-      : mem_ctx(mem_ctx),
-        tfeedback_candidates(tfeedback_candidates),
-        toplevel_var(NULL),
-        varying_floats(0)
-   {
-   }
-
-   void process(ir_variable *var)
-   {
-      /* All named varying interface blocks should be flattened by now */
-      assert(!var->is_interface_instance());
-
-      this->toplevel_var = var;
-      this->varying_floats = 0;
-      program_resource_visitor::process(var);
-   }
-
-private:
-   virtual void visit_field(const glsl_type *type, const char *name,
-                            bool row_major)
-   {
-      assert(!type->without_array()->is_record());
-      assert(!type->without_array()->is_interface());
-
-      (void) row_major;
-
-      tfeedback_candidate *candidate
-         = rzalloc(this->mem_ctx, tfeedback_candidate);
-      candidate->toplevel_var = this->toplevel_var;
-      candidate->type = type;
-      candidate->offset = this->varying_floats;
-      hash_table_insert(this->tfeedback_candidates, candidate,
-                        ralloc_strdup(this->mem_ctx, name));
-      this->varying_floats += type->component_slots();
-   }
-
-   /**
-    * Memory context used to allocate hash table keys and values.
-    */
-   void * const mem_ctx;
-
-   /**
-    * Hash table in which tfeedback_candidate objects should be stored.
-    */
-   hash_table * const tfeedback_candidates;
-
-   /**
-    * Pointer to the toplevel variable that is being traversed.
-    */
-   ir_variable *toplevel_var;
-
-   /**
-    * Total number of varying floats that have been visited so far.  This is
-    * used to determine the offset to each varying within the toplevel
-    * variable.
-    */
-   unsigned varying_floats;
-};
-
-
-namespace linker {
-
-bool
-populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
-                             hash_table *consumer_inputs,
-                             hash_table *consumer_interface_inputs,
-                             ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX])
-{
-   memset(consumer_inputs_with_locations,
-          0,
-          sizeof(consumer_inputs_with_locations[0]) * VARYING_SLOT_TESS_MAX);
-
-   foreach_in_list(ir_instruction, node, ir) {
-      ir_variable *const input_var = node->as_variable();
-
-      if ((input_var != NULL) && (input_var->data.mode == ir_var_shader_in)) {
-         if (input_var->type->is_interface())
-            return false;
-
-         if (input_var->data.explicit_location) {
-            /* assign_varying_locations only cares about finding the
-             * ir_variable at the start of a contiguous location block.
-             *
-             *     - For !producer, consumer_inputs_with_locations isn't used.
-             *
-             *     - For !consumer, consumer_inputs_with_locations is empty.
-             *
-             * For consumer && producer, if you were trying to set some
-             * ir_variable to the middle of a location block on the other side
-             * of producer/consumer, cross_validate_outputs_to_inputs() should
-             * be link-erroring due to either type mismatch or location
-             * overlaps.  If the variables do match up, then they've got a
-             * matching data.location and you only looked at
-             * consumer_inputs_with_locations[var->data.location], not any
-             * following entries for the array/structure.
-             */
-            consumer_inputs_with_locations[input_var->data.location] =
-               input_var;
-         } else if (input_var->get_interface_type() != NULL) {
-            char *const iface_field_name =
-               ralloc_asprintf(mem_ctx, "%s.%s",
-                               input_var->get_interface_type()->name,
-                               input_var->name);
-            hash_table_insert(consumer_interface_inputs, input_var,
-                              iface_field_name);
-         } else {
-            hash_table_insert(consumer_inputs, input_var,
-                              ralloc_strdup(mem_ctx, input_var->name));
-         }
-      }
-   }
-
-   return true;
-}
-
-/**
- * Find a variable from the consumer that "matches" the specified variable
- *
- * This function only finds inputs with names that match.  There is no
- * validation (here) that the types, etc. are compatible.
- */
-ir_variable *
-get_matching_input(void *mem_ctx,
-                   const ir_variable *output_var,
-                   hash_table *consumer_inputs,
-                   hash_table *consumer_interface_inputs,
-                   ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX])
-{
-   ir_variable *input_var;
-
-   if (output_var->data.explicit_location) {
-      input_var = consumer_inputs_with_locations[output_var->data.location];
-   } else if (output_var->get_interface_type() != NULL) {
-      char *const iface_field_name =
-         ralloc_asprintf(mem_ctx, "%s.%s",
-                         output_var->get_interface_type()->name,
-                         output_var->name);
-      input_var =
-         (ir_variable *) hash_table_find(consumer_interface_inputs,
-                                         iface_field_name);
-   } else {
-      input_var =
-         (ir_variable *) hash_table_find(consumer_inputs, output_var->name);
-   }
-
-   return (input_var == NULL || input_var->data.mode != ir_var_shader_in)
-      ? NULL : input_var;
-}
-
-}
-
-static int
-io_variable_cmp(const void *_a, const void *_b)
-{
-   const ir_variable *const a = *(const ir_variable **) _a;
-   const ir_variable *const b = *(const ir_variable **) _b;
-
-   if (a->data.explicit_location && b->data.explicit_location)
-      return b->data.location - a->data.location;
-
-   if (a->data.explicit_location && !b->data.explicit_location)
-      return 1;
-
-   if (!a->data.explicit_location && b->data.explicit_location)
-      return -1;
-
-   return -strcmp(a->name, b->name);
-}
-
-/**
- * Sort the shader IO variables into canonical order
- */
-static void
-canonicalize_shader_io(exec_list *ir, enum ir_variable_mode io_mode)
-{
-   ir_variable *var_table[MAX_PROGRAM_OUTPUTS * 4];
-   unsigned num_variables = 0;
-
-   foreach_in_list(ir_instruction, node, ir) {
-      ir_variable *const var = node->as_variable();
-
-      if (var == NULL || var->data.mode != io_mode)
-         continue;
-
-      /* If we have already encountered more I/O variables that could
-       * successfully link, bail.
-       */
-      if (num_variables == ARRAY_SIZE(var_table))
-         return;
-
-      var_table[num_variables++] = var;
-   }
-
-   if (num_variables == 0)
-      return;
-
-   /* Sort the list in reverse order (io_variable_cmp handles this).  Later
-    * we're going to push the variables on to the IR list as a stack, so we
-    * want the last variable (in canonical order) to be first in the list.
-    */
-   qsort(var_table, num_variables, sizeof(var_table[0]), io_variable_cmp);
-
-   /* Remove the variable from it's current location in the IR, and put it at
-    * the front.
-    */
-   for (unsigned i = 0; i < num_variables; i++) {
-      var_table[i]->remove();
-      ir->push_head(var_table[i]);
-   }
-}
-
-/**
- * Generate a bitfield map of the explicit locations for shader varyings.
- *
- * In theory a 32 bits value will be enough but a 64 bits value is future proof.
- */
-uint64_t
-reserved_varying_slot(struct gl_shader *stage, ir_variable_mode io_mode)
-{
-   assert(io_mode == ir_var_shader_in || io_mode == ir_var_shader_out);
-   assert(MAX_VARYING <= 64); /* avoid an overflow of the returned value */
-
-   uint64_t slots = 0;
-   int var_slot;
-
-   if (!stage)
-      return slots;
-
-   foreach_in_list(ir_instruction, node, stage->ir) {
-      ir_variable *const var = node->as_variable();
-
-      if (var == NULL || var->data.mode != io_mode ||
-          !var->data.explicit_location ||
-          var->data.location < VARYING_SLOT_VAR0)
-         continue;
-
-      var_slot = var->data.location - VARYING_SLOT_VAR0;
-
-      unsigned num_elements = get_varying_type(var, stage->Stage)
-         ->count_attribute_slots(stage->Stage == MESA_SHADER_VERTEX);
-      for (unsigned i = 0; i < num_elements; i++) {
-         if (var_slot >= 0 && var_slot < MAX_VARYING)
-            slots |= UINT64_C(1) << var_slot;
-         var_slot += 1;
-      }
-   }
-
-   return slots;
-}
-
-
-/**
- * Assign locations for all variables that are produced in one pipeline stage
- * (the "producer") and consumed in the next stage (the "consumer").
- *
- * Variables produced by the producer may also be consumed by transform
- * feedback.
- *
- * \param num_tfeedback_decls is the number of declarations indicating
- *        variables that may be consumed by transform feedback.
- *
- * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects
- *        representing the result of parsing the strings passed to
- *        glTransformFeedbackVaryings().  assign_location() will be called for
- *        each of these objects that matches one of the outputs of the
- *        producer.
- *
- * When num_tfeedback_decls is nonzero, it is permissible for the consumer to
- * be NULL.  In this case, varying locations are assigned solely based on the
- * requirements of transform feedback.
- */
-bool
-assign_varying_locations(struct gl_context *ctx,
-			 void *mem_ctx,
-			 struct gl_shader_program *prog,
-			 gl_shader *producer, gl_shader *consumer,
-                         unsigned num_tfeedback_decls,
-                         tfeedback_decl *tfeedback_decls)
-{
-   if (ctx->Const.DisableVaryingPacking) {
-      /* Transform feedback code assumes varyings are packed, so if the driver
-       * has disabled varying packing, make sure it does not support transform
-       * feedback.
-       */
-      assert(!ctx->Extensions.EXT_transform_feedback);
-   }
-
-   /* Tessellation shaders treat inputs and outputs as shared memory and can
-    * access inputs and outputs of other invocations.
-    * Therefore, they can't be lowered to temps easily (and definitely not
-    * efficiently).
-    */
-   bool disable_varying_packing =
-      ctx->Const.DisableVaryingPacking ||
-      (consumer && consumer->Stage == MESA_SHADER_TESS_EVAL) ||
-      (consumer && consumer->Stage == MESA_SHADER_TESS_CTRL) ||
-      (producer && producer->Stage == MESA_SHADER_TESS_CTRL);
-
-   varying_matches matches(disable_varying_packing,
-                           producer ? producer->Stage : (gl_shader_stage)-1,
-                           consumer ? consumer->Stage : (gl_shader_stage)-1);
-   hash_table *tfeedback_candidates
-      = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
-   hash_table *consumer_inputs
-      = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
-   hash_table *consumer_interface_inputs
-      = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
-   ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX] = {
-      NULL,
-   };
-
-   unsigned consumer_vertices = 0;
-   if (consumer && consumer->Stage == MESA_SHADER_GEOMETRY)
-      consumer_vertices = prog->Geom.VerticesIn;
-
-   /* Operate in a total of four passes.
-    *
-    * 1. Sort inputs / outputs into a canonical order.  This is necessary so
-    *    that inputs / outputs of separable shaders will be assigned
-    *    predictable locations regardless of the order in which declarations
-    *    appeared in the shader source.
-    *
-    * 2. Assign locations for any matching inputs and outputs.
-    *
-    * 3. Mark output variables in the producer that do not have locations as
-    *    not being outputs.  This lets the optimizer eliminate them.
-    *
-    * 4. Mark input variables in the consumer that do not have locations as
-    *    not being inputs.  This lets the optimizer eliminate them.
-    */
-   if (consumer)
-      canonicalize_shader_io(consumer->ir, ir_var_shader_in);
-
-   if (producer)
-      canonicalize_shader_io(producer->ir, ir_var_shader_out);
-
-   if (consumer
-       && !linker::populate_consumer_input_sets(mem_ctx,
-                                                consumer->ir,
-                                                consumer_inputs,
-                                                consumer_interface_inputs,
-                                                consumer_inputs_with_locations)) {
-      assert(!"populate_consumer_input_sets failed");
-      hash_table_dtor(tfeedback_candidates);
-      hash_table_dtor(consumer_inputs);
-      hash_table_dtor(consumer_interface_inputs);
-      return false;
-   }
-
-   if (producer) {
-      foreach_in_list(ir_instruction, node, producer->ir) {
-         ir_variable *const output_var = node->as_variable();
-
-         if ((output_var == NULL) ||
-             (output_var->data.mode != ir_var_shader_out))
-            continue;
-
-         /* Only geometry shaders can use non-zero streams */
-         assert(output_var->data.stream == 0 ||
-                (output_var->data.stream < MAX_VERTEX_STREAMS &&
-                 producer->Stage == MESA_SHADER_GEOMETRY));
-
-         tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates);
-         g.process(output_var);
-
-         ir_variable *const input_var =
-            linker::get_matching_input(mem_ctx, output_var, consumer_inputs,
-                                       consumer_interface_inputs,
-                                       consumer_inputs_with_locations);
-
-         /* If a matching input variable was found, add this ouptut (and the
-          * input) to the set.  If this is a separable program and there is no
-          * consumer stage, add the output.
-          *
-          * Always add TCS outputs. They are shared by all invocations
-          * within a patch and can be used as shared memory.
-          */
-         if (input_var || (prog->SeparateShader && consumer == NULL) ||
-             producer->Type == GL_TESS_CONTROL_SHADER) {
-            matches.record(output_var, input_var);
-         }
-
-         /* Only stream 0 outputs can be consumed in the next stage */
-         if (input_var && output_var->data.stream != 0) {
-            linker_error(prog, "output %s is assigned to stream=%d but "
-                         "is linked to an input, which requires stream=0",
-                         output_var->name, output_var->data.stream);
-            return false;
-         }
-      }
-   } else {
-      /* If there's no producer stage, then this must be a separable program.
-       * For example, we may have a program that has just a fragment shader.
-       * Later this program will be used with some arbitrary vertex (or
-       * geometry) shader program.  This means that locations must be assigned
-       * for all the inputs.
-       */
-      foreach_in_list(ir_instruction, node, consumer->ir) {
-         ir_variable *const input_var = node->as_variable();
-
-         if ((input_var == NULL) ||
-             (input_var->data.mode != ir_var_shader_in))
-            continue;
-
-         matches.record(NULL, input_var);
-      }
-   }
-
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-      if (!tfeedback_decls[i].is_varying())
-         continue;
-
-      const tfeedback_candidate *matched_candidate
-         = tfeedback_decls[i].find_candidate(prog, tfeedback_candidates);
-
-      if (matched_candidate == NULL) {
-         hash_table_dtor(tfeedback_candidates);
-         hash_table_dtor(consumer_inputs);
-         hash_table_dtor(consumer_interface_inputs);
-         return false;
-      }
-
-      if (matched_candidate->toplevel_var->data.is_unmatched_generic_inout)
-         matches.record(matched_candidate->toplevel_var, NULL);
-   }
-
-   const uint64_t reserved_slots =
-      reserved_varying_slot(producer, ir_var_shader_out) |
-      reserved_varying_slot(consumer, ir_var_shader_in);
-
-   const unsigned slots_used = matches.assign_locations(prog, reserved_slots,
-                                                        prog->SeparateShader);
-   matches.store_locations();
-
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-      if (!tfeedback_decls[i].is_varying())
-         continue;
-
-      if (!tfeedback_decls[i].assign_location(ctx, prog)) {
-         hash_table_dtor(tfeedback_candidates);
-         hash_table_dtor(consumer_inputs);
-         hash_table_dtor(consumer_interface_inputs);
-         return false;
-      }
-   }
-
-   hash_table_dtor(tfeedback_candidates);
-   hash_table_dtor(consumer_inputs);
-   hash_table_dtor(consumer_interface_inputs);
-
-   if (consumer && producer) {
-      foreach_in_list(ir_instruction, node, consumer->ir) {
-         ir_variable *const var = node->as_variable();
-
-         if (var && var->data.mode == ir_var_shader_in &&
-             var->data.is_unmatched_generic_inout) {
-            if (prog->IsES) {
-               /*
-                * On Page 91 (Page 97 of the PDF) of the GLSL ES 1.0 spec:
-                *
-                *     If the vertex shader declares but doesn't write to a
-                *     varying and the fragment shader declares and reads it,
-                *     is this an error?
-                *
-                *     RESOLUTION: No.
-                */
-               linker_warning(prog, "%s shader varying %s not written "
-                              "by %s shader\n.",
-                              _mesa_shader_stage_to_string(consumer->Stage),
-                              var->name,
-                              _mesa_shader_stage_to_string(producer->Stage));
-            } else if (prog->Version <= 120) {
-               /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
-                *
-                *     Only those varying variables used (i.e. read) in
-                *     the fragment shader executable must be written to
-                *     by the vertex shader executable; declaring
-                *     superfluous varying variables in a vertex shader is
-                *     permissible.
-                *
-                * We interpret this text as meaning that the VS must
-                * write the variable for the FS to read it.  See
-                * "glsl1-varying read but not written" in piglit.
-                */
-               linker_error(prog, "%s shader varying %s not written "
-                            "by %s shader\n.",
-                            _mesa_shader_stage_to_string(consumer->Stage),
-			    var->name,
-                            _mesa_shader_stage_to_string(producer->Stage));
-            }
-         }
-      }
-
-      /* Now that validation is done its safe to remove unused varyings. As
-       * we have both a producer and consumer its safe to remove unused
-       * varyings even if the program is a SSO because the stages are being
-       * linked together i.e. we have a multi-stage SSO.
-       */
-      remove_unused_shader_inputs_and_outputs(false, producer,
-                                              ir_var_shader_out);
-      remove_unused_shader_inputs_and_outputs(false, consumer,
-                                              ir_var_shader_in);
-   }
-
-   if (!disable_varying_packing) {
-      if (producer) {
-         lower_packed_varyings(mem_ctx, slots_used, ir_var_shader_out,
-                               0, producer);
-      }
-      if (consumer) {
-         lower_packed_varyings(mem_ctx, slots_used, ir_var_shader_in,
-                               consumer_vertices, consumer);
-      }
-   }
-
-   return true;
-}
-
-bool
-check_against_output_limit(struct gl_context *ctx,
-                           struct gl_shader_program *prog,
-                           gl_shader *producer)
-{
-   unsigned output_vectors = 0;
-
-   foreach_in_list(ir_instruction, node, producer->ir) {
-      ir_variable *const var = node->as_variable();
-
-      if (var && var->data.mode == ir_var_shader_out &&
-          var_counts_against_varying_limit(producer->Stage, var)) {
-         /* outputs for fragment shader can't be doubles */
-         output_vectors += var->type->count_attribute_slots(false);
-      }
-   }
-
-   assert(producer->Stage != MESA_SHADER_FRAGMENT);
-   unsigned max_output_components =
-      ctx->Const.Program[producer->Stage].MaxOutputComponents;
-
-   const unsigned output_components = output_vectors * 4;
-   if (output_components > max_output_components) {
-      if (ctx->API == API_OPENGLES2 || prog->IsES)
-         linker_error(prog, "%s shader uses too many output vectors "
-                      "(%u > %u)\n",
-                      _mesa_shader_stage_to_string(producer->Stage),
-                      output_vectors,
-                      max_output_components / 4);
-      else
-         linker_error(prog, "%s shader uses too many output components "
-                      "(%u > %u)\n",
-                      _mesa_shader_stage_to_string(producer->Stage),
-                      output_components,
-                      max_output_components);
-
-      return false;
-   }
-
-   return true;
-}
-
-bool
-check_against_input_limit(struct gl_context *ctx,
-                          struct gl_shader_program *prog,
-                          gl_shader *consumer)
-{
-   unsigned input_vectors = 0;
-
-   foreach_in_list(ir_instruction, node, consumer->ir) {
-      ir_variable *const var = node->as_variable();
-
-      if (var && var->data.mode == ir_var_shader_in &&
-          var_counts_against_varying_limit(consumer->Stage, var)) {
-         /* vertex inputs aren't varying counted */
-         input_vectors += var->type->count_attribute_slots(false);
-      }
-   }
-
-   assert(consumer->Stage != MESA_SHADER_VERTEX);
-   unsigned max_input_components =
-      ctx->Const.Program[consumer->Stage].MaxInputComponents;
-
-   const unsigned input_components = input_vectors * 4;
-   if (input_components > max_input_components) {
-      if (ctx->API == API_OPENGLES2 || prog->IsES)
-         linker_error(prog, "%s shader uses too many input vectors "
-                      "(%u > %u)\n",
-                      _mesa_shader_stage_to_string(consumer->Stage),
-                      input_vectors,
-                      max_input_components / 4);
-      else
-         linker_error(prog, "%s shader uses too many input components "
-                      "(%u > %u)\n",
-                      _mesa_shader_stage_to_string(consumer->Stage),
-                      input_components,
-                      max_input_components);
-
-      return false;
-   }
-
-   return true;
-}