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  1. /*
  2.  * Copyright © 2010 Intel Corporation
  3.  *
  4.  * Permission is hereby granted, free of charge, to any person obtaining a
  5.  * copy of this software and associated documentation files (the "Software"),
  6.  * to deal in the Software without restriction, including without limitation
  7.  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8.  * and/or sell copies of the Software, and to permit persons to whom the
  9.  * Software is furnished to do so, subject to the following conditions:
  10.  *
  11.  * The above copyright notice and this permission notice (including the next
  12.  * paragraph) shall be included in all copies or substantial portions of the
  13.  * Software.
  14.  *
  15.  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16.  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17.  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18.  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19.  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20.  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21.  * DEALINGS IN THE SOFTWARE.
  22.  */
  23.  
  24. #include "ast.h"
  25. #include "glsl_types.h"
  26. #include "ir.h"
  27.  
  28. ir_rvalue *
  29. _mesa_ast_array_index_to_hir(void *mem_ctx,
  30.                              struct _mesa_glsl_parse_state *state,
  31.                              ir_rvalue *array, ir_rvalue *idx,
  32.                              YYLTYPE &loc, YYLTYPE &idx_loc)
  33. {
  34.    if (!array->type->is_error()
  35.        && !array->type->is_array()
  36.        && !array->type->is_matrix()
  37.        && !array->type->is_vector()) {
  38.       _mesa_glsl_error(& idx_loc, state,
  39.                        "cannot dereference non-array / non-matrix / "
  40.                        "non-vector");
  41.    }
  42.  
  43.    if (!idx->type->is_error()) {
  44.       if (!idx->type->is_integer()) {
  45.          _mesa_glsl_error(& idx_loc, state, "array index must be integer type");
  46.       } else if (!idx->type->is_scalar()) {
  47.          _mesa_glsl_error(& idx_loc, state, "array index must be scalar");
  48.       }
  49.    }
  50.  
  51.    /* If the array index is a constant expression and the array has a
  52.     * declared size, ensure that the access is in-bounds.  If the array
  53.     * index is not a constant expression, ensure that the array has a
  54.     * declared size.
  55.     */
  56.    ir_constant *const const_index = idx->constant_expression_value();
  57.    if (const_index != NULL && idx->type->is_integer()) {
  58.       const int idx = const_index->value.i[0];
  59.       const char *type_name = "error";
  60.       unsigned bound = 0;
  61.  
  62.       /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec:
  63.        *
  64.        *    "It is illegal to declare an array with a size, and then
  65.        *    later (in the same shader) index the same array with an
  66.        *    integral constant expression greater than or equal to the
  67.        *    declared size. It is also illegal to index an array with a
  68.        *    negative constant expression."
  69.        */
  70.       if (array->type->is_matrix()) {
  71.          if (array->type->row_type()->vector_elements <= idx) {
  72.             type_name = "matrix";
  73.             bound = array->type->row_type()->vector_elements;
  74.          }
  75.       } else if (array->type->is_vector()) {
  76.          if (array->type->vector_elements <= idx) {
  77.             type_name = "vector";
  78.             bound = array->type->vector_elements;
  79.          }
  80.       } else {
  81.          /* glsl_type::array_size() returns 0 for non-array types.  This means
  82.           * that we don't need to verify that the type is an array before
  83.           * doing the bounds checking.
  84.           */
  85.          if ((array->type->array_size() > 0)
  86.              && (array->type->array_size() <= idx)) {
  87.             type_name = "array";
  88.             bound = array->type->array_size();
  89.          }
  90.       }
  91.  
  92.       if (bound > 0) {
  93.          _mesa_glsl_error(& loc, state, "%s index must be < %u",
  94.                           type_name, bound);
  95.       } else if (idx < 0) {
  96.          _mesa_glsl_error(& loc, state, "%s index must be >= 0",
  97.                           type_name);
  98.       }
  99.  
  100.       if (array->type->is_array()) {
  101.          /* If the array is a variable dereference, it dereferences the
  102.           * whole array, by definition.  Use this to get the variable.
  103.           *
  104.           * FINISHME: Should some methods for getting / setting / testing
  105.           * FINISHME: array access limits be added to ir_dereference?
  106.           */
  107.          ir_variable *const v = array->whole_variable_referenced();
  108.          if ((v != NULL) && (unsigned(idx) > v->max_array_access)) {
  109.             v->max_array_access = idx;
  110.  
  111.             /* Check whether this access will, as a side effect, implicitly
  112.              * cause the size of a built-in array to be too large.
  113.              */
  114.             check_builtin_array_max_size(v->name, idx+1, loc, state);
  115.          }
  116.       }
  117.    } else if (const_index == NULL && array->type->is_array()) {
  118.       if (array->type->array_size() == 0) {
  119.          _mesa_glsl_error(&loc, state, "unsized array index must be constant");
  120.       } else if (array->type->fields.array->is_interface()) {
  121.          /* Page 46 in section 4.3.7 of the OpenGL ES 3.00 spec says:
  122.           *
  123.           *     "All indexes used to index a uniform block array must be
  124.           *     constant integral expressions."
  125.           */
  126.          _mesa_glsl_error(&loc, state,
  127.                           "uniform block array index must be constant");
  128.       } else {
  129.          /* whole_variable_referenced can return NULL if the array is a
  130.           * member of a structure.  In this case it is safe to not update
  131.           * the max_array_access field because it is never used for fields
  132.           * of structures.
  133.           */
  134.          ir_variable *v = array->whole_variable_referenced();
  135.          if (v != NULL)
  136.             v->max_array_access = array->type->array_size() - 1;
  137.       }
  138.  
  139.       /* From page 23 (29 of the PDF) of the GLSL 1.30 spec:
  140.        *
  141.        *    "Samplers aggregated into arrays within a shader (using square
  142.        *    brackets [ ]) can only be indexed with integral constant
  143.        *    expressions [...]."
  144.        *
  145.        * This restriction was added in GLSL 1.30.  Shaders using earlier
  146.        * version of the language should not be rejected by the compiler
  147.        * front-end for using this construct.  This allows useful things such
  148.        * as using a loop counter as the index to an array of samplers.  If the
  149.        * loop in unrolled, the code should compile correctly.  Instead, emit a
  150.        * warning.
  151.        */
  152.       if (array->type->element_type()->is_sampler()) {
  153.          if (!state->is_version(130, 100)) {
  154.             if (state->es_shader) {
  155.                _mesa_glsl_warning(&loc, state,
  156.                                   "sampler arrays indexed with non-constant "
  157.                                   "expressions is optional in %s",
  158.                                   state->get_version_string());
  159.             } else {
  160.                _mesa_glsl_warning(&loc, state,
  161.                                   "sampler arrays indexed with non-constant "
  162.                                   "expressions will be forbidden in GLSL 1.30 "
  163.                                   "and later");
  164.             }
  165.          } else {
  166.             _mesa_glsl_error(&loc, state,
  167.                              "sampler arrays indexed with non-constant "
  168.                              "expressions is forbidden in GLSL 1.30 and "
  169.                              "later");
  170.          }
  171.       }
  172.    }
  173.  
  174.    /* After performing all of the error checking, generate the IR for the
  175.     * expression.
  176.     */
  177.    if (array->type->is_array()
  178.        || array->type->is_matrix()) {
  179.       return new(mem_ctx) ir_dereference_array(array, idx);
  180.    } else if (array->type->is_vector()) {
  181.       return new(mem_ctx) ir_expression(ir_binop_vector_extract, array, idx);
  182.    } else if (array->type->is_error()) {
  183.       return array;
  184.    } else {
  185.       ir_rvalue *result = new(mem_ctx) ir_dereference_array(array, idx);
  186.       result->type = glsl_type::error_type;
  187.  
  188.       return result;
  189.    }
  190. }
  191.