C++ ralloc_parent函数代码示例

/**
 * If the given ir satisfies is_clip_distance_vec8(), return new ir
 * representing its lowered equivalent.  That is, map:
 *
 * - gl_ClipDistance    => gl_ClipDistanceMESA    (if gl_ClipDistance is 1D)
 * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D)
 *
 * Otherwise return NULL.
 */
ir_rvalue *
lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir)
{
   if (!ir->type->is_array())
      return NULL;
   if (ir->type->fields.array != glsl_type::float_type)
      return NULL;

   ir_variable **new_var = NULL;
   if (this->old_clip_distance_out_var) {
      if (ir->variable_referenced() == this->old_clip_distance_out_var)
         new_var = &this->new_clip_distance_out_var;
   }
   if (this->old_clip_distance_in_var) {
      if (ir->variable_referenced() == this->old_clip_distance_in_var)
         new_var = &this->new_clip_distance_in_var;
   }
   if (new_var == NULL)
      return NULL;

   if (ir->as_dereference_variable()) {
      return new(ralloc_parent(ir)) ir_dereference_variable(*new_var);
   } else {
      ir_dereference_array *array_ref = ir->as_dereference_array();
      assert(array_ref);
      assert(array_ref->array->as_dereference_variable());

      return new(ralloc_parent(ir))
         ir_dereference_array(*new_var, array_ref->array_index);
   }
}

/**
 * If the given ir satisfies is_clip_distance_vec8(), return new ir
 * representing its lowered equivalent.  That is, map:
 *
 * - gl_ClipDistance    => gl_ClipDistanceMESA    (if gl_ClipDistance is 1D)
 * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D)
 *
 * Otherwise return NULL.
 */
ir_rvalue *
lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir)
{
   if (this->old_clip_distance_1d_var) {
      ir_dereference_variable *var_ref = ir->as_dereference_variable();
      if (var_ref && var_ref->var == this->old_clip_distance_1d_var) {
         return new(ralloc_parent(ir))
            ir_dereference_variable(this->new_clip_distance_1d_var);
      }
   }
   if (this->old_clip_distance_2d_var) {
      /* 2D clip distance is only possible as a geometry input */
      assert(this->shader_stage == MESA_SHADER_GEOMETRY);

      ir_dereference_array *array_ref = ir->as_dereference_array();
      if (array_ref) {
         ir_dereference_variable *var_ref =
            array_ref->array->as_dereference_variable();
         if (var_ref && var_ref->var == this->old_clip_distance_2d_var) {
            return new(ralloc_parent(ir))
               ir_dereference_array(this->new_clip_distance_2d_var,
                                    array_ref->array_index);
         }
      }
   }
   return NULL;
}

void
ir_coalesce_floats_replacing_visitor::handle_rvalue(ir_rvalue **rvalue)
{
   ir_rvalue *ir = *rvalue;
   if(!ir) return;

   ir_dereference *dv;
   ir_swizzle *swiz;

   ir_swizzle *outerswiz = ir->as_swizzle();
   if( outerswiz ) {
      dv = outerswiz->val->as_dereference();
      if(dv) {
         //fprintf(stderr, "var1: %s\n", dv->variable_referenced()->name);
         swiz = (ir_swizzle*)hash_table_find(promotions, dv->variable_referenced());
         if(swiz) {
            //fprintf(stderr, "// replacing[1] %p %p\n", ir, swiz);
            *rvalue = swiz->clone(ralloc_parent(swiz), NULL);
            return;
         }
      }
   }

   dv = ir->as_dereference();
   if(!dv) return;

   swiz = (ir_swizzle*)hash_table_find(promotions, dv->variable_referenced());

   //fprintf(stderr, "var2: %s %p\n", dv->variable_referenced()->name, dv->variable_referenced());
   if (!swiz) return;

   //fprintf(stderr, "// replacing[2] %p %p\n", ir, swiz);
   *rvalue = swiz->clone(ralloc_parent(swiz), NULL);
}

/**
 * Replace any declaration of gl_TessLevel* as an array of floats with a
 * declaration of gl_TessLevel*MESA as a vec4.
 */
ir_visitor_status
lower_tess_level_visitor::visit(ir_variable *ir)
{
   if ((!ir->name) ||
       ((strcmp(ir->name, "gl_TessLevelInner") != 0) &&
        (strcmp(ir->name, "gl_TessLevelOuter") != 0)))
      return visit_continue;

   assert (ir->type->is_array());

   if (strcmp(ir->name, "gl_TessLevelOuter") == 0) {
      if (this->old_tess_level_outer_var)
         return visit_continue;

      old_tess_level_outer_var = ir;
      assert(ir->type->fields.array == glsl_type::float_type);

      /* Clone the old var so that we inherit all of its properties */
      new_tess_level_outer_var = ir->clone(ralloc_parent(ir), NULL);

      /* And change the properties that we need to change */
      new_tess_level_outer_var->name = ralloc_strdup(new_tess_level_outer_var,
                                                "gl_TessLevelOuterMESA");
      new_tess_level_outer_var->type = glsl_type::vec4_type;
      new_tess_level_outer_var->data.max_array_access = 0;

      ir->replace_with(new_tess_level_outer_var);
   } else if (strcmp(ir->name, "gl_TessLevelInner") == 0) {
      if (this->old_tess_level_inner_var)
         return visit_continue;

      old_tess_level_inner_var = ir;
      assert(ir->type->fields.array == glsl_type::float_type);

      /* Clone the old var so that we inherit all of its properties */
      new_tess_level_inner_var = ir->clone(ralloc_parent(ir), NULL);

      /* And change the properties that we need to change */
      new_tess_level_inner_var->name = ralloc_strdup(new_tess_level_inner_var,
                                                "gl_TessLevelInnerMESA");
      new_tess_level_inner_var->type = glsl_type::vec2_type;
      new_tess_level_inner_var->data.max_array_access = 0;

      ir->replace_with(new_tess_level_inner_var);
   } else {
      assert(0);
   }

   this->progress = true;

   return visit_continue;
}

/**
 * Replace any declaration of gl_ClipDistance as an array of floats with a
 * declaration of gl_ClipDistanceMESA as an array of vec4's.
 */
ir_visitor_status
lower_clip_distance_visitor::visit(ir_variable *ir)
{
   /* No point in looking for the declaration of gl_ClipDistance if
    * we've already found it.
    */
   if (this->old_clip_distance_var)
      return visit_continue;

   if (ir->name && strcmp(ir->name, "gl_ClipDistance") == 0) {
      this->progress = true;
      this->old_clip_distance_var = ir;
      assert (ir->type->is_array());
      assert (ir->type->element_type() == glsl_type::float_type);
      unsigned new_size = (ir->type->array_size() + 3) / 4;

      /* Clone the old var so that we inherit all of its properties */
      this->new_clip_distance_var = ir->clone(ralloc_parent(ir), NULL);

      /* And change the properties that we need to change */
      this->new_clip_distance_var->name
         = ralloc_strdup(this->new_clip_distance_var, "gl_ClipDistanceMESA");
      this->new_clip_distance_var->type
         = glsl_type::get_array_instance(glsl_type::vec4_type, new_size);
      this->new_clip_distance_var->max_array_access = ir->max_array_access / 4;

      ir->replace_with(this->new_clip_distance_var);
   }
   return visit_continue;
}

ir_visitor_status
output_read_remover::visit(ir_dereference_variable *ir)
{
   if (ir->var->data.mode != ir_var_shader_out)
      return visit_continue;
   if (stage == MESA_SHADER_TESS_CTRL)
      return visit_continue;

   hash_entry *entry = _mesa_hash_table_search(replacements, ir->var);
   ir_variable *temp = entry ? (ir_variable *) entry->data : NULL;

   /* If we don't have an existing temporary, create one. */
   if (temp == NULL) {
      void *var_ctx = ralloc_parent(ir->var);
      temp = new(var_ctx) ir_variable(ir->var->type, ir->var->name,
                                      ir_var_temporary);
      _mesa_hash_table_insert(replacements, ir->var, temp);
      ir->var->insert_after(temp);
   }

   /* Update the dereference to use the temporary */
   ir->var = temp;

   return visit_continue;
}

static bool
opt_undef_alu(nir_alu_instr *instr)
{
   if (instr->op != nir_op_bcsel && instr->op != nir_op_fcsel)
      return false;

   assert(instr->dest.dest.is_ssa);

   for (int i = 1; i <= 2; i++) {
      if (!instr->src[i].src.is_ssa)
         continue;

      nir_instr *parent = instr->src[i].src.ssa->parent_instr;
      if (parent->type != nir_instr_type_ssa_undef)
         continue;

      /* We can't just use nir_alu_src_copy, because we need the def/use
       * updated.
       */
      nir_instr_rewrite_src(&instr->instr, &instr->src[0].src,
                            instr->src[i == 1 ? 2 : 1].src);
      nir_alu_src_copy(&instr->src[0], &instr->src[i == 1 ? 2 : 1],
                       ralloc_parent(instr));

      nir_src empty_src;
      memset(&empty_src, 0, sizeof(empty_src));
      nir_instr_rewrite_src(&instr->instr, &instr->src[1].src, empty_src);
      nir_instr_rewrite_src(&instr->instr, &instr->src[2].src, empty_src);
      instr->op = nir_op_imov;

      return true;
   }

   return false;
}

ir_rvalue *
ir_vec_index_to_swizzle_visitor::convert_vector_extract_to_swizzle(ir_rvalue *ir)
{
   ir_expression *const expr = ir->as_expression();
   if (expr == NULL || expr->operation != ir_binop_vector_extract)
      return ir;

   ir_constant *const idx = expr->operands[1]->constant_expression_value();
   if (idx == NULL)
      return ir;

   void *ctx = ralloc_parent(ir);
   this->progress = true;

   /* Page 40 of the GLSL 1.20 spec says:
    *
    *     "When indexing with non-constant expressions, behavior is undefined
    *     if the index is negative, or greater than or equal to the size of
    *     the vector."
    *
    * The quoted spec text mentions non-constant expressions, but this code
    * operates on constants.  These constants are the result of non-constant
    * expressions that have been optimized to constants.  The common case here
    * is a loop counter from an unrolled loop that is used to index a vector.
    *
    * The ir_swizzle constructor gets angry if the index is negative or too
    * large.  For simplicity sake, just clamp the index to [0, size-1].
    */
   const int i = CLAMP(idx->value.i[0], 0,
                       (int) expr->operands[0]->type->vector_elements - 1);

   return new(ctx) ir_swizzle(expr->operands[0], i, 0, 0, 0, 1);
}

	void generate(unsigned i, ir_rvalue* condition, exec_list *list) const
	{
		/* Just clone the rest of the deref chain when trying to get at the
		* underlying variable.
		*/
		void *mem_ctx = ralloc_parent(base_ir);

		/* Clone the old r-value in its entirety.  Then replace any occurances of
		* the old variable index with the new constant index.
		*/
		ir_dereference *element = this->rvalue->clone(mem_ctx, NULL);
		ir_constant *const index = new(mem_ctx)ir_constant(i);
		deref_replacer r(this->old_index, index);
		element->accept(&r);
		check(r.progress);

		/* Generate a conditional assignment to (or from) the constant indexed
		* array dereference.
		*/
		ir_rvalue *variable = new(mem_ctx)ir_dereference_variable(this->var);
		ir_assignment *const assignment = (is_write)
			? new(mem_ctx)ir_assignment(element, variable, condition, write_mask)
			: new(mem_ctx)ir_assignment(variable, element, condition);

		list->push_tail(assignment);
	}

/**
 * If a 1D gl_ClipDistance variable appears as an argument in an ir_call
 * expression, replace it with a temporary variable, and make sure the ir_call
 * is preceded and/or followed by assignments that copy the contents of the
 * temporary variable to and/or from gl_ClipDistance.  Each of these
 * assignments is then lowered to refer to gl_ClipDistanceMESA.
 *
 * We need to do a similar replacement for 2D gl_ClipDistance, however since
 * it's an input, the only case we need to address is where a 1D slice of it
 * is passed as an "in" parameter to an ir_call, e.g.:
 *
 *     foo(gl_in[i].gl_ClipDistance)
 */
ir_visitor_status
lower_clip_distance_visitor::visit_leave(ir_call *ir)
{
   void *ctx = ralloc_parent(ir);

   const exec_node *formal_param_node = ir->callee->parameters.head;
   const exec_node *actual_param_node = ir->actual_parameters.head;
   while (!actual_param_node->is_tail_sentinel()) {
      ir_variable *formal_param = (ir_variable *) formal_param_node;
      ir_rvalue *actual_param = (ir_rvalue *) actual_param_node;

      /* Advance formal_param_node and actual_param_node now so that we can
       * safely replace actual_param with another node, if necessary, below.
       */
      formal_param_node = formal_param_node->next;
      actual_param_node = actual_param_node->next;

      if (this->is_clip_distance_vec8(actual_param)) {
         /* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D
          * slice of a 2D gl_ClipDistance array) to a function call.  Since we
          * are reshaping gl_ClipDistance from an array of floats to an array
          * of vec4's, this isn't going to work anymore, so use a temporary
          * array instead.
          */
         ir_variable *temp_clip_distance = new(ctx) ir_variable(
            actual_param->type, "temp_clip_distance", ir_var_temporary, actual_param->get_precision());
         this->base_ir->insert_before(temp_clip_distance);
         actual_param->replace_with(
            new(ctx) ir_dereference_variable(temp_clip_distance));
         if (formal_param->data.mode == ir_var_function_in
             || formal_param->data.mode == ir_var_function_inout) {
            /* Copy from gl_ClipDistance to the temporary before the call.
             * Since we are going to insert this copy before the current
             * instruction, we need to visit it afterwards to make sure it
             * gets lowered.
             */
            ir_assignment *new_assignment = new(ctx) ir_assignment(
               new(ctx) ir_dereference_variable(temp_clip_distance),
               actual_param->clone(ctx, NULL));
            this->base_ir->insert_before(new_assignment);
            this->visit_new_assignment(new_assignment);
         }
         if (formal_param->data.mode == ir_var_function_out
             || formal_param->data.mode == ir_var_function_inout) {
            /* Copy from the temporary to gl_ClipDistance after the call.
             * Since visit_list_elements() has already decided which
             * instruction it's going to visit next, we need to visit
             * afterwards to make sure it gets lowered.
             */
            ir_assignment *new_assignment = new(ctx) ir_assignment(
               actual_param->clone(ctx, NULL),
               new(ctx) ir_dereference_variable(temp_clip_distance));
            this->base_ir->insert_after(new_assignment);
            this->visit_new_assignment(new_assignment);
         }
      }
   }

   return rvalue_visit(ir);
}

void
lower_tess_level_visitor::handle_rvalue(ir_rvalue **rv)
{
   if (*rv == NULL)
      return;

   ir_dereference_array *const array_deref = (*rv)->as_dereference_array();
   if (array_deref == NULL)
      return;

   /* Replace any expression that indexes one of the floats in gl_TessLevel*
    * with an expression that indexes into one of the vec4's
    * gl_TessLevel*MESA and accesses the appropriate component.
    */
   ir_rvalue *lowered_vec4 =
      this->lower_tess_level_array(array_deref->array);
   if (lowered_vec4 != NULL) {
      this->progress = true;
      void *mem_ctx = ralloc_parent(array_deref);

      ir_expression *const expr =
         new(mem_ctx) ir_expression(ir_binop_vector_extract,
                                    lowered_vec4,
                                    array_deref->array_index);

      *rv = expr;
   }
}

ir_expression *
expr(ir_expression_operation op, operand a, operand b)
{
   void *mem_ctx = ralloc_parent(a.val);

   return new(mem_ctx) ir_expression(op, a.val, b.val);
}

static void
validate_deref_chain(nir_deref *deref, validate_state *state)
{
   assert(deref->child == NULL || ralloc_parent(deref->child) == deref);

   nir_deref *parent = NULL;
   while (deref != NULL) {
      switch (deref->deref_type) {
      case nir_deref_type_array:
         assert(deref->type == glsl_get_array_element(parent->type));
         if (nir_deref_as_array(deref)->deref_array_type ==
             nir_deref_array_type_indirect)
            validate_src(&nir_deref_as_array(deref)->indirect, state);
         break;

      case nir_deref_type_struct:
         assert(deref->type ==
                glsl_get_struct_field(parent->type,
                                      nir_deref_as_struct(deref)->index));
         break;

      case nir_deref_type_var:
         break;

      default:
         assert(!"Invalid deref type");
         break;
      }

      parent = deref;
      deref = deref->child;
   }
}

ir_expression *
bitfield_insert(operand a, operand b, operand c, operand d)
{
   void *mem_ctx = ralloc_parent(a.val);
   return new(mem_ctx) ir_expression(ir_quadop_bitfield_insert,
                                     a.val->type, a.val, b.val, c.val, d.val);
}

/**
 * Replace any assignment having gl_ClipDistance (undereferenced) as its LHS
 * or RHS with a sequence of assignments, one for each component of the array.
 * Each of these assignments is lowered to refer to gl_ClipDistanceMESA as
 * appropriate.
 */
ir_visitor_status
lower_clip_distance_visitor::visit_leave(ir_assignment *ir)
{
   ir_dereference_variable *lhs_var = ir->lhs->as_dereference_variable();
   ir_dereference_variable *rhs_var = ir->rhs->as_dereference_variable();
   if ((lhs_var && lhs_var->var == this->old_clip_distance_var)
       || (rhs_var && rhs_var->var == this->old_clip_distance_var)) {
      /* LHS or RHS of the assignment is the entire gl_ClipDistance array.
       * Since we are reshaping gl_ClipDistance from an array of floats to an
       * array of vec4's, this isn't going to work as a bulk assignment
       * anymore, so unroll it to element-by-element assignments and lower
       * each of them.
       *
       * Note: to unroll into element-by-element assignments, we need to make
       * clones of the LHS and RHS.  This is safe because expressions and
       * l-values are side-effect free.
       */
      void *ctx = ralloc_parent(ir);
      int array_size = this->old_clip_distance_var->type->array_size();
      for (int i = 0; i < array_size; ++i) {
         ir_dereference_array *new_lhs = new(ctx) ir_dereference_array(
            ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i));
         ir_dereference_array *new_rhs = new(ctx) ir_dereference_array(
            ir->rhs->clone(ctx, NULL), new(ctx) ir_constant(i));
         this->handle_rvalue((ir_rvalue **) &new_rhs);

         /* Handle the LHS after creating the new assignment.  This must
          * happen in this order because handle_rvalue may replace the old LHS
          * with an ir_expression of ir_binop_vector_extract.  Since this is
          * not a valide l-value, this will cause an assertion in the
          * ir_assignment constructor to fail.
          *
          * If this occurs, replace the mangled LHS with a dereference of the
          * vector, and replace the RHS with an ir_triop_vector_insert.
          */
         ir_assignment *const assign = new(ctx) ir_assignment(new_lhs, new_rhs);
         this->handle_rvalue((ir_rvalue **) &assign->lhs);
         this->fix_lhs(assign);

         this->base_ir->insert_before(assign);
      }
      ir->remove();

      return visit_continue;
   }

   /* Handle the LHS as if it were an r-value.  Normally
    * rvalue_visit(ir_assignment *) only visits the RHS, but we need to lower
    * expressions in the LHS as well.
    *
    * This may cause the LHS to get replaced with an ir_expression of
    * ir_binop_vector_extract.  If this occurs, replace it with a dereference
    * of the vector, and replace the RHS with an ir_triop_vector_insert.
    */
   handle_rvalue((ir_rvalue **)&ir->lhs);
   this->fix_lhs(ir);

   return rvalue_visit(ir);
}