src/glsl/hir_field_selection.cpp

   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 "ir.h"
  25 #include "program/symbol_table.h"
  26 #include "glsl_parser_extras.h"
  27 #include "ast.h"
  28 #include "glsl_types.h"
  29
  30 using std::strcmp;
  31
  32 ir_rvalue *
  33 _mesa_ast_field_selection_to_hir(const ast_expression *expr,
  34                                  exec_list *instructions,
  35                                  struct _mesa_glsl_parse_state *state)
  36 {
  37    void *ctx = state;
  38    ir_rvalue *result = NULL;
  39    ir_rvalue *op;
  40
  41    op = expr->subexpressions[0]->hir(instructions, state);
  42
  43    /* There are two kinds of field selection.  There is the selection of a
  44     * specific field from a structure, and there is the selection of a
  45     * swizzle / mask from a vector.  Which is which is determined entirely
  46     * by the base type of the thing to which the field selection operator is
  47     * being applied.
  48     */
  49    YYLTYPE loc = expr->get_location();
  50    if (op->type->is_error()) {
  51       /* silently propagate the error */
  52    } else if (op->type->is_vector()) {
  53       ir_swizzle *swiz = ir_swizzle::create(op,
  54                                             expr->primary_expression.identifier,
  55                                             op->type->vector_elements);
  56       if (swiz != NULL) {
  57          result = swiz;
  58       } else {
  59          /* FINISHME: Logging of error messages should be moved into
  60           * FINISHME: ir_swizzle::create.  This allows the generation of more
  61           * FINISHME: specific error messages.
  62           */
  63          _mesa_glsl_error(& loc, state, "Invalid swizzle / mask `%s'",
  64                           expr->primary_expression.identifier);
  65       }
  66    } else if (op->type->base_type == GLSL_TYPE_STRUCT) {
  67       result = new(ctx) ir_dereference_record(op,
  68                                               expr->primary_expression.identifier);
  69
  70       if (result->type->is_error()) {
  71          _mesa_glsl_error(& loc, state, "Cannot access field `%s' of "
  72                           "structure",
  73                           expr->primary_expression.identifier);
  74       }
  75    } else if (expr->subexpressions[1] != NULL) {
  76       /* Handle "method calls" in GLSL 1.20 - namely, array.length() */
  77       if (state->language_version < 120)
  78          _mesa_glsl_error(&loc, state, "Methods not supported in GLSL 1.10.");
  79
  80       ast_expression *call = expr->subexpressions[1];
  81       assert(call->oper == ast_function_call);
  82
  83       const char *method;
  84       method = call->subexpressions[0]->primary_expression.identifier;
  85
  86       if (op->type->is_array() && strcmp(method, "length") == 0) {
  87          if (!call->expressions.is_empty())
  88             _mesa_glsl_error(&loc, state, "length method takes no arguments.");
  89
  90          if (op->type->array_size() == 0)
  91             _mesa_glsl_error(&loc, state, "length called on unsized array.");
  92
  93          result = new(ctx) ir_constant(op->type->array_size());
  94       } else {
  95          _mesa_glsl_error(&loc, state, "Unknown method: `%s'.", method);
  96       }
  97    } else {
  98       _mesa_glsl_error(& loc, state, "Cannot access field `%s' of "
  99                        "non-structure / non-vector.",
 100                        expr->primary_expression.identifier);
 101    }
 102
 103    return result ? result : ir_call::get_error_instruction(ctx);
 104 }