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/*

 * Copyright © 2013 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_interface_blocks.cpp

 * Linker support for GLSL's interface blocks.

 */

#include "ir.h"

#include "glsl_symbol_table.h"

#include "linker.h"

#include "main/macros.h"

#include "program/hash_table.h"

namespace {

/**

 * Information about a single interface block definition that we need to keep

 * track of in order to check linkage rules.

 *

 * Note: this class is expected to be short lived, so it doesn't make copies

 * of the strings it references; it simply borrows the pointers from the

 * ir_variable class.

 */

struct interface_block_definition

{

   /**

    * Extract an interface block definition from an ir_variable that

    * represents either the interface instance (for named interfaces), or a

    * member of the interface (for unnamed interfaces).

    */

   explicit interface_block_definition(ir_variable *var)

      : var(var),

        type(var->get_interface_type()),

        instance_name(NULL)

   {

      if (var->is_interface_instance()) {

         instance_name = var->name;

      }

      explicitly_declared = (var->data.how_declared != ir_var_declared_implicitly);

   }

   /**

    * Interface block ir_variable

    */

   ir_variable *var;

   /**

    * Interface block type

    */

   const glsl_type *type;

   /**

    * For a named interface block, the instance name.  Otherwise NULL.

    */

   const char *instance_name;

   /**

    * True if this interface block was explicitly declared in the shader;

    * false if it was an implicitly declared built-in interface block.

    */

   bool explicitly_declared;

};

/**

 * Check if two interfaces match, according to intrastage interface matching

 * rules.  If they do, and the first interface uses an unsized array, it will

 * be updated to reflect the array size declared in the second interface.

 */

bool

intrastage_match(interface_block_definition *a,

                 const interface_block_definition *b,

                 ir_variable_mode mode,

                 struct gl_shader_program *prog)

{

   /* Types must match. */

   if (a->type != b->type) {

      /* Exception: if both the interface blocks are implicitly declared,

       * don't force their types to match.  They might mismatch due to the two

       * shaders using different GLSL versions, and that's ok.

       */

      if (a->explicitly_declared || b->explicitly_declared)

         return false;

   }

   /* Presence/absence of interface names must match. */

   if ((a->instance_name == NULL) != (b->instance_name == NULL))

      return false;

   /* For uniforms, instance names need not match.  For shader ins/outs,

    * it's not clear from the spec whether they need to match, but

    * Mesa's implementation relies on them matching.

    */

   if (a->instance_name != NULL && mode != ir_var_uniform &&

       strcmp(a->instance_name, b->instance_name) != 0) {

      return false;

   }

   /* If a block is an array then it must match across the shader.

    * Unsized arrays are also processed and matched agaist sized arrays.

    */

   if (b->var->type != a->var->type &&

       (b->instance_name != NULL || a->instance_name != NULL) &&

       !validate_intrastage_arrays(prog, b->var, a->var))

      return false;

   return true;

}

/**

 * Check if two interfaces match, according to interstage (in/out) interface

 * matching rules.

 *

 * If \c extra_array_level is true, then vertex-to-geometry shader matching

 * rules are enforced (i.e. a successful match requires the consumer interface

 * to be an array and the producer interface to be a non-array).

 */

bool

interstage_match(const interface_block_definition *producer,

                 const interface_block_definition *consumer,

                 bool extra_array_level)

{

   /* Unsized arrays should not occur during interstage linking.  They

    * should have all been assigned a size by link_intrastage_shaders.

    */

   assert(!consumer->var->type->is_unsized_array());

   assert(!producer->var->type->is_unsized_array());

   /* Types must match. */

   if (consumer->type != producer->type) {

      /* Exception: if both the interface blocks are implicitly declared,

       * don't force their types to match.  They might mismatch due to the two

       * shaders using different GLSL versions, and that's ok.

       */

      if (consumer->explicitly_declared || producer->explicitly_declared)

         return false;

   }

   /* Ignore outermost array if geom shader */

   const glsl_type *consumer_instance_type;

   if (extra_array_level) {

      consumer_instance_type = consumer->var->type->fields.array;

   } else {

      consumer_instance_type = consumer->var->type;

   }

   /* If a block is an array then it must match across shaders.

    * Since unsized arrays have been ruled out, we can check this by just

    * making sure the types are equal.

    */

   if ((consumer->instance_name != NULL &&

        consumer_instance_type->is_array()) ||

       (producer->instance_name != NULL &&

        producer->var->type->is_array())) {

      if (consumer_instance_type != producer->var->type)

         return false;

   }

   return true;

}

/**

 * This class keeps track of a mapping from an interface block name to the

 * necessary information about that interface block to determine whether to

 * generate a link error.

 *

 * Note: this class is expected to be short lived, so it doesn't make copies

 * of the strings it references; it simply borrows the pointers from the

 * ir_variable class.

 */

class interface_block_definitions

{

public:

   interface_block_definitions()

      : mem_ctx(ralloc_context(NULL)),

        ht(hash_table_ctor(0, hash_table_string_hash,

                           hash_table_string_compare))

   {

   }

   ~interface_block_definitions()

   {

      hash_table_dtor(ht);

      ralloc_free(mem_ctx);

   }

   /**

    * Lookup the interface definition having the given block name.  Return

    * NULL if none is found.

    */

   interface_block_definition *lookup(const char *block_name)

   {

      return (interface_block_definition *) hash_table_find(ht, block_name);

   }

   /**

    * Add a new interface definition.

    */

   void store(const interface_block_definition &def)

   {

      interface_block_definition *hash_entry =

         rzalloc(mem_ctx, interface_block_definition);

      *hash_entry = def;

      hash_table_insert(ht, hash_entry, def.type->name);

   }

private:

   /**

    * Ralloc context for data structures allocated by this class.

    */

   void *mem_ctx;

   /**

    * Hash table mapping interface block name to an \c

    * interface_block_definition struct.  interface_block_definition structs

    * are allocated using \c mem_ctx.

    */

   hash_table *ht;

};

}; /* anonymous namespace */

void

validate_intrastage_interface_blocks(struct gl_shader_program *prog,

                                     const gl_shader **shader_list,

                                     unsigned num_shaders)

{

   interface_block_definitions in_interfaces;

   interface_block_definitions out_interfaces;

   interface_block_definitions uniform_interfaces;

   for (unsigned int i = 0; i < num_shaders; i++) {

      if (shader_list[i] == NULL)

         continue;

      foreach_in_list(ir_instruction, node, shader_list[i]->ir) {

         ir_variable *var = node->as_variable();

         if (!var)

            continue;

         const glsl_type *iface_type = var->get_interface_type();

         if (iface_type == NULL)

            continue;

         interface_block_definitions *definitions;

         switch (var->data.mode) {

         case ir_var_shader_in:

            definitions = &in_interfaces;

            break;

         case ir_var_shader_out:

            definitions = &out_interfaces;

            break;

         case ir_var_uniform:

            definitions = &uniform_interfaces;

            break;

         default:

            /* Only in, out, and uniform interfaces are legal, so we should

             * never get here.

             */

            assert(!"illegal interface type");

            continue;

         }

         const interface_block_definition def(var);

         interface_block_definition *prev_def =

            definitions->lookup(iface_type->name);

         if (prev_def == NULL) {

            /* This is the first time we've seen the interface, so save

             * it into the appropriate data structure.

             */

            definitions->store(def);

         } else if (!intrastage_match(prev_def, &def,

                                      (ir_variable_mode) var->data.mode,

                                      prog)) {

            linker_error(prog, "definitions of interface block `%s' do not"

                         " match\n", iface_type->name);

            return;

         }

      }

   }

}

void

validate_interstage_inout_blocks(struct gl_shader_program *prog,

                                 const gl_shader *producer,

                                 const gl_shader *consumer)

{

   interface_block_definitions definitions;

   const bool extra_array_level = consumer->Stage == MESA_SHADER_GEOMETRY;

   /* Add input interfaces from the consumer to the symbol table. */

   foreach_in_list(ir_instruction, node, consumer->ir) {

      ir_variable *var = node->as_variable();

      if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_in)

         continue;

      definitions.store(interface_block_definition(var));

   }

   /* Verify that the producer's output interfaces match. */

   foreach_in_list(ir_instruction, node, producer->ir) {

      ir_variable *var = node->as_variable();

      if (!var || !var->get_interface_type() || var->data.mode != ir_var_shader_out)

         continue;

      interface_block_definition *consumer_def =

         definitions.lookup(var->get_interface_type()->name);

      /* The consumer doesn't use this output block.  Ignore it. */

      if (consumer_def == NULL)

         continue;

      const interface_block_definition producer_def(var);

      if (!interstage_match(&producer_def, consumer_def, extra_array_level)) {

         linker_error(prog, "definitions of interface block `%s' do not "

                      "match\n", var->get_interface_type()->name);

         return;

      }

   }

}

void

validate_interstage_uniform_blocks(struct gl_shader_program *prog,

                                   gl_shader **stages, int num_stages)

{

   interface_block_definitions definitions;

   for (int i = 0; i < num_stages; i++) {

      if (stages[i] == NULL)

         continue;

      const gl_shader *stage = stages[i];

      foreach_in_list(ir_instruction, node, stage->ir) {

         ir_variable *var = node->as_variable();

         if (!var || !var->get_interface_type() || var->data.mode != ir_var_uniform)

            continue;

         interface_block_definition *old_def =

            definitions.lookup(var->get_interface_type()->name);

         const interface_block_definition new_def(var);

         if (old_def == NULL) {

            definitions.store(new_def);

         } else {

            /* Interstage uniform matching rules are the same as intrastage

             * uniform matchin rules (for uniforms, it is as though all

             * shaders are in the same shader stage).

             */

            if (!intrastage_match(old_def, &new_def, ir_var_uniform, prog)) {

               linker_error(prog, "definitions of interface block `%s' do not "

                            "match\n", var->get_interface_type()->name);

               return;

            }

         }

      }

   }

}