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