glsl: Refactor handling of ast_array_index to a separate function

I love 800+ line switch-statements as much as the next guy... Future
commits will make changes to this part of the AST-to-HIR conversion, and
extracting this code will make that a bit easier.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 194 insertions, 0 deletions

diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
new file mode 100644
index 00000000000..fecda4592b6
--- /dev/null
+++ b/src/glsl/ast_array_index.cpp
@@ -0,0 +1,194 @@
+/*
+ * 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 "ast.h"
+#include "glsl_types.h"
+#include "ir.h"
+
+ir_rvalue *
+_mesa_ast_array_index_to_hir(void *mem_ctx,
+			     struct _mesa_glsl_parse_state *state,
+			     ir_rvalue *array, ir_rvalue *idx,
+			     YYLTYPE &loc, YYLTYPE &idx_loc,
+			     bool error_emitted)
+{
+   ir_rvalue *result = new(mem_ctx) ir_dereference_array(array, idx);
+
+   if (error_emitted)
+      return result;
+
+   if (!array->type->is_array()
+       && !array->type->is_matrix()
+       && !array->type->is_vector()) {
+      _mesa_glsl_error(& idx_loc, state,
+		       "cannot dereference non-array / non-matrix / "
+		       "non-vector");
+      error_emitted = true;
+   }
+
+   if (!idx->type->is_integer()) {
+      _mesa_glsl_error(& idx_loc, state,
+		       "array index must be integer type");
+      error_emitted = true;
+   } else if (!idx->type->is_scalar()) {
+      _mesa_glsl_error(& idx_loc, state,
+		       "array index must be scalar");
+      error_emitted = true;
+   }
+
+   /* If the array index is a constant expression and the array has a
+    * declared size, ensure that the access is in-bounds.  If the array
+    * index is not a constant expression, ensure that the array has a
+    * declared size.
+    */
+   ir_constant *const const_index = idx->constant_expression_value();
+   if (const_index != NULL) {
+      const int idx = const_index->value.i[0];
+      const char *type_name;
+      unsigned bound = 0;
+
+      if (array->type->is_matrix()) {
+	 type_name = "matrix";
+      } else if (array->type->is_vector()) {
+	 type_name = "vector";
+      } else {
+	 type_name = "array";
+      }
+
+      /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec:
+       *
+       *    "It is illegal to declare an array with a size, and then
+       *    later (in the same shader) index the same array with an
+       *    integral constant expression greater than or equal to the
+       *    declared size. It is also illegal to index an array with a
+       *    negative constant expression."
+       */
+      if (array->type->is_matrix()) {
+	 if (array->type->row_type()->vector_elements <= idx) {
+	    bound = array->type->row_type()->vector_elements;
+	 }
+      } else if (array->type->is_vector()) {
+	 if (array->type->vector_elements <= idx) {
+	    bound = array->type->vector_elements;
+	 }
+      } else {
+	 if ((array->type->array_size() > 0)
+	     && (array->type->array_size() <= idx)) {
+	    bound = array->type->array_size();
+	 }
+      }
+
+      if (bound > 0) {
+	 _mesa_glsl_error(& loc, state, "%s index must be < %u",
+			  type_name, bound);
+	 error_emitted = true;
+      } else if (idx < 0) {
+	 _mesa_glsl_error(& loc, state, "%s index must be >= 0",
+			  type_name);
+	 error_emitted = true;
+      }
+
+      if (array->type->is_array()) {
+	 /* If the array is a variable dereference, it dereferences the
+	  * whole array, by definition.  Use this to get the variable.
+	  *
+	  * FINISHME: Should some methods for getting / setting / testing
+	  * FINISHME: array access limits be added to ir_dereference?
+	  */
+	 ir_variable *const v = array->whole_variable_referenced();
+	 if ((v != NULL) && (unsigned(idx) > v->max_array_access)) {
+	    v->max_array_access = idx;
+
+	    /* Check whether this access will, as a side effect, implicitly
+	     * cause the size of a built-in array to be too large.
+	     */
+	    if (check_builtin_array_max_size(v->name, idx+1, loc, state))
+	       error_emitted = true;
+	 }
+      }
+   } else if (array->type->array_size() == 0) {
+      _mesa_glsl_error(&loc, state, "unsized array index must be constant");
+   } else if (array->type->is_array()
+	      && array->type->fields.array->is_interface()) {
+      /* Page 46 in section 4.3.7 of the OpenGL ES 3.00 spec says:
+       *
+       *     "All indexes used to index a uniform block array must be
+       *     constant integral expressions."
+       */
+      _mesa_glsl_error(&loc, state,
+		       "uniform block array index must be constant");
+   } else {
+      if (array->type->is_array()) {
+	 /* whole_variable_referenced can return NULL if the array is a
+	  * member of a structure.  In this case it is safe to not update
+	  * the max_array_access field because it is never used for fields
+	  * of structures.
+	  */
+	 ir_variable *v = array->whole_variable_referenced();
+	 if (v != NULL)
+	    v->max_array_access = array->type->array_size() - 1;
+      }
+   }
+
+   /* From page 23 (29 of the PDF) of the GLSL 1.30 spec:
+    *
+    *    "Samplers aggregated into arrays within a shader (using square
+    *    brackets [ ]) can only be indexed with integral constant
+    *    expressions [...]."
+    *
+    * This restriction was added in GLSL 1.30.  Shaders using earlier version
+    * of the language should not be rejected by the compiler front-end for
+    * using this construct.  This allows useful things such as using a loop
+    * counter as the index to an array of samplers.  If the loop in unrolled,
+    * the code should compile correctly.  Instead, emit a warning.
+    */
+   if (array->type->is_array() &&
+       array->type->element_type()->is_sampler() &&
+       const_index == NULL) {
+
+      if (!state->is_version(130, 100)) {
+	 if (state->es_shader) {
+	    _mesa_glsl_warning(&loc, state,
+			       "sampler arrays indexed with non-constant "
+			       "expressions is optional in %s",
+			       state->get_version_string());
+	 } else {
+	    _mesa_glsl_warning(&loc, state,
+			       "sampler arrays indexed with non-constant "
+			       "expressions will be forbidden in GLSL 1.30 and "
+			       "later");
+	 }
+      } else {
+	 _mesa_glsl_error(&loc, state,
+			  "sampler arrays indexed with non-constant "
+			  "expressions is forbidden in GLSL 1.30 and "
+			  "later");
+	 error_emitted = true;
+      }
+   }
+
+   if (error_emitted)
+      result->type = glsl_type::error_type;
+
+   return result;
+}