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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. void
  29. ast_array_specifier::print(void) const
  30. {
  31.    if (this->is_unsized_array) {
  32.       printf("[ ] ");
  33.    }
  34.  
  35.    foreach_list_typed (ast_node, array_dimension, link, &this->array_dimensions) {
  36.       printf("[ ");
  37.       array_dimension->print();
  38.       printf("] ");
  39.    }
  40. }
  41.  
  42. /**
  43.  * If \c ir is a reference to an array for which we are tracking the max array
  44.  * element accessed, track that the given element has been accessed.
  45.  * Otherwise do nothing.
  46.  *
  47.  * This function also checks whether the array is a built-in array whose
  48.  * maximum size is too small to accommodate the given index, and if so uses
  49.  * loc and state to report the error.
  50.  */
  51. static void
  52. update_max_array_access(ir_rvalue *ir, int idx, YYLTYPE *loc,
  53.                         struct _mesa_glsl_parse_state *state)
  54. {
  55.    if (ir_dereference_variable *deref_var = ir->as_dereference_variable()) {
  56.       ir_variable *var = deref_var->var;
  57.       if (idx > (int)var->data.max_array_access) {
  58.          var->data.max_array_access = idx;
  59.  
  60.          /* Check whether this access will, as a side effect, implicitly cause
  61.           * the size of a built-in array to be too large.
  62.           */
  63.          check_builtin_array_max_size(var->name, idx+1, *loc, state);
  64.       }
  65.    } else if (ir_dereference_record *deref_record =
  66.               ir->as_dereference_record()) {
  67.       /* There are two possibilities we need to consider:
  68.        *
  69.        * - Accessing an element of an array that is a member of a named
  70.        *   interface block (e.g. ifc.foo[i])
  71.        *
  72.        * - Accessing an element of an array that is a member of a named
  73.        *   interface block array (e.g. ifc[j].foo[i]).
  74.        */
  75.       ir_dereference_variable *deref_var =
  76.          deref_record->record->as_dereference_variable();
  77.       if (deref_var == NULL) {
  78.          if (ir_dereference_array *deref_array =
  79.              deref_record->record->as_dereference_array()) {
  80.             deref_var = deref_array->array->as_dereference_variable();
  81.          }
  82.       }
  83.  
  84.       if (deref_var != NULL) {
  85.          if (deref_var->var->is_interface_instance()) {
  86.             unsigned field_index =
  87.                deref_record->record->type->field_index(deref_record->field);
  88.             assert(field_index < deref_var->var->get_interface_type()->length);
  89.  
  90.             unsigned *const max_ifc_array_access =
  91.                deref_var->var->get_max_ifc_array_access();
  92.  
  93.             assert(max_ifc_array_access != NULL);
  94.  
  95.             if (idx > (int)max_ifc_array_access[field_index]) {
  96.                max_ifc_array_access[field_index] = idx;
  97.  
  98.                /* Check whether this access will, as a side effect, implicitly
  99.                 * cause the size of a built-in array to be too large.
  100.                 */
  101.                check_builtin_array_max_size(deref_record->field, idx+1, *loc,
  102.                                             state);
  103.             }
  104.          }
  105.       }
  106.    }
  107. }
  108.  
  109.  
  110. ir_rvalue *
  111. _mesa_ast_array_index_to_hir(void *mem_ctx,
  112.                              struct _mesa_glsl_parse_state *state,
  113.                              ir_rvalue *array, ir_rvalue *idx,
  114.                              YYLTYPE &loc, YYLTYPE &idx_loc)
  115. {
  116.    if (!array->type->is_error()
  117.        && !array->type->is_array()
  118.        && !array->type->is_matrix()
  119.        && !array->type->is_vector()) {
  120.       _mesa_glsl_error(& idx_loc, state,
  121.                        "cannot dereference non-array / non-matrix / "
  122.                        "non-vector");
  123.    }
  124.  
  125.    if (!idx->type->is_error()) {
  126.       if (!idx->type->is_integer()) {
  127.          _mesa_glsl_error(& idx_loc, state, "array index must be integer type");
  128.       } else if (!idx->type->is_scalar()) {
  129.          _mesa_glsl_error(& idx_loc, state, "array index must be scalar");
  130.       }
  131.    }
  132.  
  133.    /* If the array index is a constant expression and the array has a
  134.     * declared size, ensure that the access is in-bounds.  If the array
  135.     * index is not a constant expression, ensure that the array has a
  136.     * declared size.
  137.     */
  138.    ir_constant *const const_index = idx->constant_expression_value();
  139.    if (const_index != NULL && idx->type->is_integer()) {
  140.       const int idx = const_index->value.i[0];
  141.       const char *type_name = "error";
  142.       unsigned bound = 0;
  143.  
  144.       /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec:
  145.        *
  146.        *    "It is illegal to declare an array with a size, and then
  147.        *    later (in the same shader) index the same array with an
  148.        *    integral constant expression greater than or equal to the
  149.        *    declared size. It is also illegal to index an array with a
  150.        *    negative constant expression."
  151.        */
  152.       if (array->type->is_matrix()) {
  153.          if (array->type->row_type()->vector_elements <= idx) {
  154.             type_name = "matrix";
  155.             bound = array->type->row_type()->vector_elements;
  156.          }
  157.       } else if (array->type->is_vector()) {
  158.          if (array->type->vector_elements <= idx) {
  159.             type_name = "vector";
  160.             bound = array->type->vector_elements;
  161.          }
  162.       } else {
  163.          /* glsl_type::array_size() returns -1 for non-array types.  This means
  164.           * that we don't need to verify that the type is an array before
  165.           * doing the bounds checking.
  166.           */
  167.          if ((array->type->array_size() > 0)
  168.              && (array->type->array_size() <= idx)) {
  169.             type_name = "array";
  170.             bound = array->type->array_size();
  171.          }
  172.       }
  173.  
  174.       if (bound > 0) {
  175.          _mesa_glsl_error(& loc, state, "%s index must be < %u",
  176.                           type_name, bound);
  177.       } else if (idx < 0) {
  178.          _mesa_glsl_error(& loc, state, "%s index must be >= 0",
  179.                           type_name);
  180.       }
  181.  
  182.       if (array->type->is_array())
  183.          update_max_array_access(array, idx, &loc, state);
  184.    } else if (const_index == NULL && array->type->is_array()) {
  185.       if (array->type->is_unsized_array()) {
  186.          _mesa_glsl_error(&loc, state, "unsized array index must be constant");
  187.       } else if (array->type->fields.array->is_interface()
  188.                  && array->variable_referenced()->data.mode == ir_var_uniform
  189.                  && !state->is_version(400, 0) && !state->ARB_gpu_shader5_enable) {
  190.          /* Page 46 in section 4.3.7 of the OpenGL ES 3.00 spec says:
  191.           *
  192.           *     "All indexes used to index a uniform block array must be
  193.           *     constant integral expressions."
  194.           */
  195.          _mesa_glsl_error(&loc, state,
  196.                           "uniform block array index must be constant");
  197.       } else {
  198.          /* whole_variable_referenced can return NULL if the array is a
  199.           * member of a structure.  In this case it is safe to not update
  200.           * the max_array_access field because it is never used for fields
  201.           * of structures.
  202.           */
  203.          ir_variable *v = array->whole_variable_referenced();
  204.          if (v != NULL)
  205.             v->data.max_array_access = array->type->array_size() - 1;
  206.       }
  207.  
  208.       /* From page 23 (29 of the PDF) of the GLSL 1.30 spec:
  209.        *
  210.        *    "Samplers aggregated into arrays within a shader (using square
  211.        *    brackets [ ]) can only be indexed with integral constant
  212.        *    expressions [...]."
  213.        *
  214.        * This restriction was added in GLSL 1.30.  Shaders using earlier
  215.        * version of the language should not be rejected by the compiler
  216.        * front-end for using this construct.  This allows useful things such
  217.        * as using a loop counter as the index to an array of samplers.  If the
  218.        * loop in unrolled, the code should compile correctly.  Instead, emit a
  219.        * warning.
  220.        *
  221.        * In GLSL 4.00 / ARB_gpu_shader5, this requirement is relaxed again to allow
  222.        * indexing with dynamically uniform expressions. Note that these are not
  223.        * required to be uniforms or expressions based on them, but merely that the
  224.        * values must not diverge between shader invocations run together. If the
  225.        * values *do* diverge, then the behavior of the operation requiring a
  226.        * dynamically uniform expression is undefined.
  227.        */
  228.       if (array->type->element_type()->is_sampler()) {
  229.          if (!state->is_version(130, 100)) {
  230.             if (state->es_shader) {
  231.                _mesa_glsl_warning(&loc, state,
  232.                                   "sampler arrays indexed with non-constant "
  233.                                   "expressions is optional in %s",
  234.                                   state->get_version_string());
  235.             } else {
  236.                _mesa_glsl_warning(&loc, state,
  237.                                   "sampler arrays indexed with non-constant "
  238.                                   "expressions will be forbidden in GLSL 1.30 "
  239.                                   "and later");
  240.             }
  241.          } else if (!state->is_version(400, 0) && !state->ARB_gpu_shader5_enable) {
  242.             _mesa_glsl_error(&loc, state,
  243.                              "sampler arrays indexed with non-constant "
  244.                              "expressions is forbidden in GLSL 1.30 and "
  245.                              "later");
  246.          }
  247.       }
  248.    }
  249.  
  250.    /* After performing all of the error checking, generate the IR for the
  251.     * expression.
  252.     */
  253.    if (array->type->is_array()
  254.        || array->type->is_matrix()) {
  255.       return new(mem_ctx) ir_dereference_array(array, idx);
  256.    } else if (array->type->is_vector()) {
  257.       return new(mem_ctx) ir_expression(ir_binop_vector_extract, array, idx);
  258.    } else if (array->type->is_error()) {
  259.       return array;
  260.    } else {
  261.       ir_rvalue *result = new(mem_ctx) ir_dereference_array(array, idx);
  262.       result->type = glsl_type::error_type;
  263.  
  264.       return result;
  265.    }
  266. }
  267.