[mesa.git] / ast_function.cpp

/*
 * Copyright © 2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <cstdio>
#include "glsl_symbol_table.h"
#include "ast.h"
#include "glsl_types.h"
#include "ir.h"

static ir_rvalue *
match_function_by_name(exec_list *instructions, const char *name,
                       YYLTYPE *loc, simple_node *parameters,
                       struct _mesa_glsl_parse_state *state)
{
   ir_function *f = state->symbols->get_function(name);

   if (f == NULL) {
      _mesa_glsl_error(loc, state, "function `%s' undeclared", name);
      return ir_call::get_error_instruction();
   }

   /* Once we've determined that the function being called might exist,
    * process the parameters.
    */
   exec_list actual_parameters;
   simple_node *const first = parameters;
   if (first != NULL) {
      simple_node *ptr = first;
      do {
         ir_instruction *const result =
            ((ast_node *) ptr)->hir(instructions, state);
         ptr = ptr->next;

         actual_parameters.push_tail(result);
      } while (ptr != first);
   }

   /* After processing the function's actual parameters, try to find an
    * overload of the function that matches.
    */
   const ir_function_signature *sig =
      f->matching_signature(& actual_parameters);
   if (sig != NULL) {
      /* FINISHME: The list of actual parameters needs to be modified to
       * FINISHME: include any necessary conversions.
       */
      return new ir_call(sig, & actual_parameters);
   } else {
      /* FINISHME: Log a better error message here.  G++ will show the types
       * FINISHME: of the actual parameters and the set of candidate
       * FINISHME: functions.  A different error should also be logged when
       * FINISHME: multiple functions match.
       */
      _mesa_glsl_error(loc, state, "no matching function for call to `%s'",
                       name);
      return ir_call::get_error_instruction();
   }
}


/**
 * Perform automatic type conversion of constructor parameters
 */
static ir_rvalue *
convert_component(ir_rvalue *src, const glsl_type *desired_type)
{
   const unsigned a = desired_type->base_type;
   const unsigned b = src->type->base_type;

   if (src->type->is_error())
      return src;

   assert(a <= GLSL_TYPE_BOOL);
   assert(b <= GLSL_TYPE_BOOL);

   if ((a == b) || (src->type->is_integer() && desired_type->is_integer()))
      return src;

   switch (a) {
   case GLSL_TYPE_UINT:
   case GLSL_TYPE_INT:
      if (b == GLSL_TYPE_FLOAT)
         return new ir_expression(ir_unop_f2i, desired_type, src, NULL);
      else {
         assert(b == GLSL_TYPE_BOOL);
         assert(!"FINISHME: Convert bool to int / uint.");
      }
   case GLSL_TYPE_FLOAT:
      switch (b) {
      case GLSL_TYPE_UINT:
         return new ir_expression(ir_unop_u2f, desired_type, src, NULL);
      case GLSL_TYPE_INT:
         return new ir_expression(ir_unop_i2f, desired_type, src, NULL);
      case GLSL_TYPE_BOOL:
         assert(!"FINISHME: Convert bool to float.");
      }
      break;
   case GLSL_TYPE_BOOL: {
      int z = 0;
      ir_constant *const zero = new ir_constant(src->type, &z);

      return new ir_expression(ir_binop_nequal, desired_type, src, zero);
   }
   }

   assert(!"Should not get here.");
   return NULL;
}


/**
 * Dereference a specific component from a scalar, vector, or matrix
 */
static ir_rvalue *
dereference_component(ir_rvalue *src, unsigned component)
{
   assert(component < src->type->components());

   if (src->type->is_scalar()) {
      return src;
   } else if (src->type->is_vector()) {
      return new ir_swizzle(src, component, 0, 0, 0, 1);
   } else {
      assert(src->type->is_matrix());

      /* Dereference a row of the matrix, then call this function again to get
       * a specific element from that row.
       */
      const int c = component / src->type->column_type()->vector_elements;
      const int r = component % src->type->column_type()->vector_elements;
      ir_constant *const col_index = new ir_constant(glsl_type::int_type, &c);
      ir_dereference *const col = new ir_dereference(src, col_index);

      col->type = src->type->column_type();

      return dereference_component(col, r);
   }

   assert(!"Should not get here.");
   return NULL;
}


ir_rvalue *
ast_function_expression::hir(exec_list *instructions,
                             struct _mesa_glsl_parse_state *state)
{
   /* There are three sorts of function calls.
    *
    * 1. contstructors - The first subexpression is an ast_type_specifier.
    * 2. methods - Only the .length() method of array types.
    * 3. functions - Calls to regular old functions.
    *
    * Method calls are actually detected when the ast_field_selection
    * expression is handled.
    */
   if (is_constructor()) {
      const ast_type_specifier *type = (ast_type_specifier *) subexpressions[0];
      YYLTYPE loc = type->get_location();

      const glsl_type *const constructor_type =
         state->symbols->get_type(type->type_name);


      /* Constructors for samplers are illegal.
       */
      if (constructor_type->is_sampler()) {
         _mesa_glsl_error(& loc, state, "cannot construct sampler type `%s'",
                          constructor_type->name);
         return ir_call::get_error_instruction();
      }


      /* There are two kinds of constructor call.  Constructors for built-in
       * language types, such as mat4 and vec2, are free form.  The only
       * requirement is that the parameters must provide enough values of the
       * correct scalar type.  Constructors for arrays and structures must
       * have the exact number of parameters with matching types in the
       * correct order.  These constructors follow essentially the same type
       * matching rules as functions.
       */
      if (constructor_type->is_numeric() || constructor_type->is_boolean()) {
         /* Constructing a numeric type has a couple steps.  First all values
          * passed to the constructor are broken into individual parameters
          * and type converted to the base type of the thing being constructed.
          *
          * At that point we have some number of values that match the base
          * type of the thing being constructed.  Now the constructor can be
          * treated like a function call.  Each numeric type has a small set
          * of constructor functions.  The set of new parameters will either
          * match one of those functions or the original constructor is
          * invalid.
          */
         const glsl_type *const base_type = constructor_type->get_base_type();

         /* Total number of components of the type being constructed.
          */
         const unsigned type_components = constructor_type->components();

         /* Number of components from parameters that have actually been
          * consumed.  This is used to perform several kinds of error checking.
          */
         unsigned components_used = 0;

         unsigned matrix_parameters = 0;
         unsigned nonmatrix_parameters = 0;
         exec_list actual_parameters;
         simple_node *const first = subexpressions[1];

         assert(first != NULL);

         if (first != NULL) {
            simple_node *ptr = first;
            do {
               ir_rvalue *const result =
                  ((ast_node *) ptr)->hir(instructions, state)->as_rvalue();
               ptr = ptr->next;

               /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
                *
                *    "It is an error to provide extra arguments beyond this
                *    last used argument."
                */
               if (components_used >= type_components) {
                  _mesa_glsl_error(& loc, state, "too many parameters to `%s' "
                                   "constructor",
                                   constructor_type->name);
                  return ir_call::get_error_instruction();
               }

               if (!result->type->is_numeric() && !result->type->is_boolean()) {
                  _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
                                   "non-numeric data type",
                                   constructor_type->name);
                  return ir_call::get_error_instruction();
               }

               /* Count the number of matrix and nonmatrix parameters.  This
                * is used below to enforce some of the constructor rules.
                */
               if (result->type->is_matrix())
                  matrix_parameters++;
               else
                  nonmatrix_parameters++;


               /* Process each of the components of the parameter.  Dereference
                * each component individually, perform any type conversions, and
                * add it to the parameter list for the constructor.
                */
               for (unsigned i = 0; i < result->type->components(); i++) {
                  if (components_used >= type_components)
                     break;

                  ir_rvalue *const component =
                     convert_component(dereference_component(result, i),
                                       base_type);

                  /* All cases that could result in component->type being the
                   * error type should have already been caught above.
                   */
                  assert(component->type == base_type);

                  /* Don't actually generate constructor calls for scalars.
                   * Instead, do the usual component selection and conversion,
                   * and return the single component.
                   */
                  if (constructor_type->is_scalar())
                     return component;

                  actual_parameters.push_tail(component);
                  components_used++;
               }
            } while (ptr != first);
         }

         /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
          *
          *    "It is an error to construct matrices from other matrices. This
          *    is reserved for future use."
          */
         if ((state->language_version <= 110) && (matrix_parameters > 0)
             && constructor_type->is_matrix()) {
            _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
                             "matrix in GLSL 1.10",
                             constructor_type->name);
            return ir_call::get_error_instruction();
         }

         /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
          *
          *    "If a matrix argument is given to a matrix constructor, it is
          *    an error to have any other arguments."
          */
         if ((matrix_parameters > 0)
             && ((matrix_parameters + nonmatrix_parameters) > 1)
             && constructor_type->is_matrix()) {
            _mesa_glsl_error(& loc, state, "for matrix `%s' constructor, "
                             "matrix must be only parameter",
                             constructor_type->name);
            return ir_call::get_error_instruction();
         }

         /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
          *
          *    "In these cases, there must be enough components provided in the
          *    arguments to provide an initializer for every component in the
          *    constructed value."
          */
         if (components_used < type_components) {
            _mesa_glsl_error(& loc, state, "too few components to construct "
                             "`%s'",
                             constructor_type->name);
            return ir_call::get_error_instruction();
         }

         ir_function *f = state->symbols->get_function(constructor_type->name);
         if (f == NULL) {
            _mesa_glsl_error(& loc, state, "no constructor for type `%s'",
                             constructor_type->name);
            return ir_call::get_error_instruction();
         }

         const ir_function_signature *sig =
            f->matching_signature(& actual_parameters);
         if (sig != NULL) {
            return new ir_call(sig, & actual_parameters);
         } else {
            /* FINISHME: Log a better error message here.  G++ will show the
             * FINSIHME: types of the actual parameters and the set of
             * FINSIHME: candidate functions.  A different error should also be
             * FINSIHME: logged when multiple functions match.
             */
            _mesa_glsl_error(& loc, state, "no matching constructor for `%s'",
                             constructor_type->name);
            return ir_call::get_error_instruction();
         }
      }

      return ir_call::get_error_instruction();
   } else {
      const ast_expression *id = subexpressions[0];
      YYLTYPE loc = id->get_location();

      return match_function_by_name(instructions, 
                                    id->primary_expression.identifier, & loc,
                                    subexpressions[1], state);
   }

   return ir_call::get_error_instruction();
}