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 <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

4 files changed, 205 insertions, 162 deletions

diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
index b5282a6..674a05f 100644
--- a/src/glsl/Makefile.sources
+++ b/src/glsl/Makefile.sources
@@ -16,6 +16,7 @@ LIBGLCPP_GENERATED_FILES = \
 # libglsl
 
 LIBGLSL_FILES = \
+	$(GLSL_SRCDIR)/ast_array_index.cpp \
 	$(GLSL_SRCDIR)/ast_expr.cpp \
 	$(GLSL_SRCDIR)/ast_function.cpp \
 	$(GLSL_SRCDIR)/ast_to_hir.cpp \
diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index 3a61f79..475fb99 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -854,6 +854,13 @@ _mesa_ast_field_selection_to_hir(const ast_expression *expr,
 				 exec_list *instructions,
 				 struct _mesa_glsl_parse_state *state);
 
+extern 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);
+
 void
 emit_function(_mesa_glsl_parse_state *state, ir_function *f);
 
diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
new file mode 100644
index 0000000..fecda45
--- /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;
+}
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index c9d00b1..5980cb0 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1519,170 +1519,11 @@ ast_expression::hir(exec_list *instructions,
 
       error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
 
-      ir_rvalue *const array = op[0];
+      result = _mesa_ast_array_index_to_hir(ctx, state, op[0], op[1],
+					    loc, index_loc, error_emitted);
 
-      result = new(ctx) ir_dereference_array(op[0], op[1]);
-
-      /* Do not use op[0] after this point.  Use array.
-       */
-      op[0] = NULL;
-
-
-      if (error_emitted)
-	 break;
-
-      if (!array->type->is_array()
-	  && !array->type->is_matrix()
-	  && !array->type->is_vector()) {
-	 _mesa_glsl_error(& index_loc, state,
-			  "cannot dereference non-array / non-matrix / "
-			  "non-vector");
+      if (result->type->is_error())
 	 error_emitted = true;
-      }
-
-      if (!op[1]->type->is_integer()) {
-	 _mesa_glsl_error(& index_loc, state,
-			  "array index must be integer type");
-	 error_emitted = true;
-      } else if (!op[1]->type->is_scalar()) {
-	 _mesa_glsl_error(& index_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 = op[1]->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;
 
       break;
    }