6 files changed, 509 insertions, 397 deletions
diff --git a/mesalib/src/glsl/ast_function.cpp b/mesalib/src/glsl/ast_function.cpp
index 39401017b..8bf0ba2a8 100644
--- a/mesalib/src/glsl/ast_function.cpp
+++ b/mesalib/src/glsl/ast_function.cpp
@@ -152,19 +152,22 @@ verify_parameter_modes(_mesa_glsl_parse_state *state,
 	    return false;
 	 }
 
-	 if (actual->variable_referenced()
-	     && actual->variable_referenced()->read_only) {
-	    _mesa_glsl_error(&loc, state,
-			     "function parameter '%s %s' references the "
-			     "read-only variable '%s'",
-			     mode, formal->name,
-			     actual->variable_referenced()->name);
-	    return false;
-	 } else if (!actual->is_lvalue()) {
-	    _mesa_glsl_error(&loc, state,
-			     "function parameter '%s %s' is not an lvalue",
-			     mode, formal->name);
-	    return false;
+	 ir_variable *var = actual->variable_referenced();
+	 if (var) {
+	    if (var->read_only) {
+	       _mesa_glsl_error(&loc, state,
+				"function parameter '%s %s' references the "
+				"read-only variable '%s'",
+				mode, formal->name,
+				actual->variable_referenced()->name);
+	       return false;
+	    } else if (!actual->is_lvalue()) {
+	       _mesa_glsl_error(&loc, state,
+				"function parameter '%s %s' is not an lvalue",
+				mode, formal->name);
+	       return false;
+	    }
+	    var->assigned = true;
 	 }
       }
 
diff --git a/mesalib/src/glsl/ast_to_hir.cpp b/mesalib/src/glsl/ast_to_hir.cpp
index 820c86c5e..e24914b83 100644
--- a/mesalib/src/glsl/ast_to_hir.cpp
+++ b/mesalib/src/glsl/ast_to_hir.cpp
@@ -57,6 +57,10 @@
 #include "program/hash_table.h"
 #include "ir.h"
 
+static void
+detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
+			       exec_list *instructions);
+
 void
 _mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state)
 {
@@ -87,6 +91,7 @@ _mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state)
       ast->hir(instructions, state);
 
    detect_recursion_unlinked(state, instructions);
+   detect_conflicting_assignments(state, instructions);
 
    state->toplevel_ir = NULL;
 }
@@ -672,6 +677,10 @@ do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
    void *ctx = state;
    bool error_emitted = (lhs->type->is_error() || rhs->type->is_error());
 
+   ir_variable *lhs_var = lhs->variable_referenced();
+   if (lhs_var)
+      lhs_var->assigned = true;
+
    if (!error_emitted) {
       if (non_lvalue_description != NULL) {
          _mesa_glsl_error(&lhs_loc, state,
@@ -4013,3 +4022,64 @@ ast_struct_specifier::hir(exec_list *instructions,
     */
    return NULL;
 }
+
+static void
+detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
+			       exec_list *instructions)
+{
+   bool gl_FragColor_assigned = false;
+   bool gl_FragData_assigned = false;
+   bool user_defined_fs_output_assigned = false;
+   ir_variable *user_defined_fs_output = NULL;
+
+   /* It would be nice to have proper location information. */
+   YYLTYPE loc;
+   memset(&loc, 0, sizeof(loc));
+
+   foreach_list(node, instructions) {
+      ir_variable *var = ((ir_instruction *)node)->as_variable();
+
+      if (!var)
+	 continue;
+
+      if (strcmp(var->name, "gl_FragColor") == 0)
+	 gl_FragColor_assigned = var->assigned;
+      else if (strcmp(var->name, "gl_FragData") == 0)
+	 gl_FragData_assigned = var->assigned;
+      else if (strncmp(var->name, "gl_", 3) != 0) {
+	 if (state->target == fragment_shader &&
+	     (var->mode == ir_var_out || var->mode == ir_var_inout)) {
+	    user_defined_fs_output_assigned = true;
+	    user_defined_fs_output = var;
+	 }
+      }
+   }
+
+   /* From the GLSL 1.30 spec:
+    *
+    *     "If a shader statically assigns a value to gl_FragColor, it
+    *      may not assign a value to any element of gl_FragData. If a
+    *      shader statically writes a value to any element of
+    *      gl_FragData, it may not assign a value to
+    *      gl_FragColor. That is, a shader may assign values to either
+    *      gl_FragColor or gl_FragData, but not both. Multiple shaders
+    *      linked together must also consistently write just one of
+    *      these variables.  Similarly, if user declared output
+    *      variables are in use (statically assigned to), then the
+    *      built-in variables gl_FragColor and gl_FragData may not be
+    *      assigned to. These incorrect usages all generate compile
+    *      time errors."
+    */
+   if (gl_FragColor_assigned && gl_FragData_assigned) {
+      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
+		       "`gl_FragColor' and `gl_FragData'\n");
+   } else if (gl_FragColor_assigned && user_defined_fs_output_assigned) {
+      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
+		       "`gl_FragColor' and `%s'\n",
+		       user_defined_fs_output->name);
+   } else if (gl_FragData_assigned && user_defined_fs_output_assigned) {
+      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
+		       "`gl_FragData' and `%s'\n",
+		       user_defined_fs_output->name);
+   }
+}
diff --git a/mesalib/src/glsl/ir.h b/mesalib/src/glsl/ir.h
index d6c6a607a..ddfaf3614 100644
--- a/mesalib/src/glsl/ir.h
+++ b/mesalib/src/glsl/ir.h
@@ -353,10 +353,23 @@ public:
     * Several GLSL semantic checks require knowledge of whether or not a
     * variable has been used.  For example, it is an error to redeclare a
     * variable as invariant after it has been used.
+    *
+    * This is only maintained in the ast_to_hir.cpp path, not in
+    * Mesa's fixed function or ARB program paths.
     */
    unsigned used:1;
 
    /**
+    * Has this variable been statically assigned?
+    *
+    * This answers whether the variable was assigned in any path of
+    * the shader during ast_to_hir.  This doesn't answer whether it is
+    * still written after dead code removal, nor is it maintained in
+    * non-ast_to_hir.cpp (GLSL parsing) paths.
+    */
+   unsigned assigned:1;
+
+   /**
     * Storage class of the variable.
     *
     * \sa ir_variable_mode
diff --git a/mesalib/src/glsl/main.cpp b/mesalib/src/glsl/main.cpp
index f04a146e8..8c651b8c0 100644
--- a/mesalib/src/glsl/main.cpp
+++ b/mesalib/src/glsl/main.cpp
@@ -249,7 +249,7 @@ main(int argc, char **argv)
 	 usage_fail(argv[0]);
 
       const char *const ext = & argv[optind][len - 5];
-      if (strncmp(".vert", ext, 5) == 0)
+      if (strncmp(".vert", ext, 5) == 0 || strncmp(".glsl", ext, 5) == 0)
 	 shader->Type = GL_VERTEX_SHADER;
       else if (strncmp(".geom", ext, 5) == 0)
 	 shader->Type = GL_GEOMETRY_SHADER;
diff --git a/mesalib/src/glsl/opt_array_splitting.cpp b/mesalib/src/glsl/opt_array_splitting.cpp
index f11b51631..67733ca6b 100644
--- a/mesalib/src/glsl/opt_array_splitting.cpp
+++ b/mesalib/src/glsl/opt_array_splitting.cpp
@@ -49,7 +49,7 @@ public:
    variable_entry(ir_variable *var)
    {
       this->var = var;
-      this->whole_array_access = 0;
+      this->split = true;
       this->declaration = false;
       this->components = NULL;
       this->mem_ctx = NULL;
@@ -62,10 +62,14 @@ public:
    ir_variable *var; /* The key: the variable's pointer. */
    unsigned size; /* array length or matrix columns */
 
-   /** Number of times the variable is referenced, including assignments. */
-   unsigned whole_array_access;
+   /** Whether this array should be split or not. */
+   bool split;
 
-   bool declaration; /* If the variable had a decl in the instruction stream */
+   /* If the variable had a decl we can work with in the instruction
+    * stream.  We can't do splitting on function arguments, which
+    * don't get this variable set.
+    */
+   bool declaration;
 
    ir_variable **components;
 
@@ -99,6 +103,7 @@ public:
    virtual ir_visitor_status visit(ir_variable *);
    virtual ir_visitor_status visit(ir_dereference_variable *);
    virtual ir_visitor_status visit_enter(ir_dereference_array *);
+   virtual ir_visitor_status visit_enter(ir_function_signature *);
 
    variable_entry *get_variable_entry(ir_variable *var);
 
@@ -154,12 +159,13 @@ ir_array_reference_visitor::visit(ir_dereference_variable *ir)
 {
    variable_entry *entry = this->get_variable_entry(ir->var);
 
-   /* If we made it to here, then the dereference of this array didn't
-    * have a constant index (see the visit_continue_with_parent
-    * below), so we can't split the variable.
+   /* If we made it to here without seeing an ir_dereference_array,
+    * then the dereference of this array didn't have a constant index
+    * (see the visit_continue_with_parent below), so we can't split
+    * the variable.
     */
    if (entry)
-      entry->whole_array_access++;
+      entry->split = false;
 
    return visit_continue;
 }
@@ -173,12 +179,26 @@ ir_array_reference_visitor::visit_enter(ir_dereference_array *ir)
 
    variable_entry *entry = this->get_variable_entry(deref->var);
 
+   /* If the access to the array has a variable index, we wouldn't
+    * know which split variable this dereference should go to.
+    */
    if (entry && !ir->array_index->as_constant())
-      entry->whole_array_access++;
+      entry->split = false;
 
    return visit_continue_with_parent;
 }
 
+ir_visitor_status
+ir_array_reference_visitor::visit_enter(ir_function_signature *ir)
+{
+   /* We don't have logic for array-splitting function arguments,
+    * so just look at the body instructions and not the parameter
+    * declarations.
+    */
+   visit_list_elements(this, &ir->body);
+   return visit_continue_with_parent;
+}
+
 bool
 ir_array_reference_visitor::get_split_list(exec_list *instructions,
 					   bool linked)
@@ -204,12 +224,12 @@ ir_array_reference_visitor::get_split_list(exec_list *instructions,
       variable_entry *entry = (variable_entry *)iter.get();
 
       if (debug) {
-	 printf("array %s@%p: decl %d, whole_access %d\n",
+	 printf("array %s@%p: decl %d, split %d\n",
 		entry->var->name, (void *) entry->var, entry->declaration,
-		entry->whole_array_access);
+		entry->split);
       }
 
-      if (!entry->declaration || entry->whole_array_access) {
+      if (!(entry->declaration && entry->split)) {
 	 entry->remove();
       }
    }
@@ -217,7 +237,10 @@ ir_array_reference_visitor::get_split_list(exec_list *instructions,
    return !variable_list.is_empty();
 }
 
-/** This is the class that does the actual work of splitting. */
+/**
+ * This class rewrites the dereferences of arrays that have been split
+ * to use the newly created ir_variables for each component.
+ */
 class ir_array_splitting_visitor : public ir_rvalue_visitor {
 public:
    ir_array_splitting_visitor(exec_list *vars)
@@ -236,7 +259,6 @@ public:
    variable_entry *get_splitting_entry(ir_variable *var);
 
    exec_list *variable_list;
-   void *mem_ctx;
 };
 
 variable_entry *
@@ -348,8 +370,7 @@ optimize_split_arrays(exec_list *instructions, bool linked)
       const struct glsl_type *subtype;
 
       if (type->is_matrix())
-	 subtype = glsl_type::get_instance(GLSL_TYPE_FLOAT,
-					   type->vector_elements, 1);
+	 subtype = type->column_type();
       else
 	 subtype = type->fields.array;
 
diff --git a/mesalib/src/glsl/opt_structure_splitting.cpp b/mesalib/src/glsl/opt_structure_splitting.cpp
index d08a5cee1..6dd228e4e 100644
--- a/mesalib/src/glsl/opt_structure_splitting.cpp
+++ b/mesalib/src/glsl/opt_structure_splitting.cpp
@@ -1,367 +1,372 @@
-/*
- * 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.
- */
-
-/**
- * \file opt_structure_splitting.cpp
- *
- * If a structure is only ever referenced by its components, then
- * split those components out to individual variables so they can be
- * handled normally by other optimization passes.
- *
- * This skips structures like uniforms, which need to be accessible as
- * structures for their access by the GL.
- */
-
-#include "ir.h"
-#include "ir_visitor.h"
-#include "ir_print_visitor.h"
-#include "ir_rvalue_visitor.h"
-#include "glsl_types.h"
-
-static bool debug = false;
-
-// XXX using variable_entry2 here to avoid collision (MSVC multiply-defined
-// function) with the variable_entry class seen in ir_variable_refcount.h
-// Perhaps we can use the one in ir_variable_refcount.h and make this class
-// here go away?
-class variable_entry2 : public exec_node
-{
-public:
-   variable_entry2(ir_variable *var)
-   {
-      this->var = var;
-      this->whole_structure_access = 0;
-      this->declaration = false;
-      this->components = NULL;
-      this->mem_ctx = NULL;
-   }
-
-   ir_variable *var; /* The key: the variable's pointer. */
-
-   /** Number of times the variable is referenced, including assignments. */
-   unsigned whole_structure_access;
-
-   bool declaration; /* If the variable had a decl in the instruction stream */
-
-   ir_variable **components;
-
-   /** ralloc_parent(this->var) -- the shader's ralloc context. */
-   void *mem_ctx;
-};
-
-
-class ir_structure_reference_visitor : public ir_hierarchical_visitor {
-public:
-   ir_structure_reference_visitor(void)
-   {
-      this->mem_ctx = ralloc_context(NULL);
-      this->variable_list.make_empty();
-   }
-
-   ~ir_structure_reference_visitor(void)
-   {
-      ralloc_free(mem_ctx);
-   }
-
-   virtual ir_visitor_status visit(ir_variable *);
-   virtual ir_visitor_status visit(ir_dereference_variable *);
-   virtual ir_visitor_status visit_enter(ir_dereference_record *);
-   virtual ir_visitor_status visit_enter(ir_assignment *);
-   virtual ir_visitor_status visit_enter(ir_function_signature *);
-
-   variable_entry2 *get_variable_entry2(ir_variable *var);
-
-   /* List of variable_entry */
-   exec_list variable_list;
-
-   void *mem_ctx;
-};
-
-variable_entry2 *
-ir_structure_reference_visitor::get_variable_entry2(ir_variable *var)
-{
-   assert(var);
-
-   if (!var->type->is_record() || var->mode == ir_var_uniform)
-      return NULL;
-
-   foreach_iter(exec_list_iterator, iter, this->variable_list) {
-      variable_entry2 *entry = (variable_entry2 *)iter.get();
-      if (entry->var == var)
-	 return entry;
-   }
-
-   variable_entry2 *entry = new(mem_ctx) variable_entry2(var);
-   this->variable_list.push_tail(entry);
-   return entry;
-}
-
-
-ir_visitor_status
-ir_structure_reference_visitor::visit(ir_variable *ir)
-{
-   variable_entry2 *entry = this->get_variable_entry2(ir);
-
-   if (entry)
-      entry->declaration = true;
-
-   return visit_continue;
-}
-
-ir_visitor_status
-ir_structure_reference_visitor::visit(ir_dereference_variable *ir)
-{
-   ir_variable *const var = ir->variable_referenced();
-   variable_entry2 *entry = this->get_variable_entry2(var);
-
-   if (entry)
-      entry->whole_structure_access++;
-
-   return visit_continue;
-}
-
-ir_visitor_status
-ir_structure_reference_visitor::visit_enter(ir_dereference_record *ir)
-{
-   (void) ir;
-   /* Don't descend into the ir_dereference_variable below. */
-   return visit_continue_with_parent;
-}
-
-ir_visitor_status
-ir_structure_reference_visitor::visit_enter(ir_assignment *ir)
-{
-   /* If there are no structure references yet, no need to bother with
-    * processing the expression tree.
-    */
-   if (this->variable_list.is_empty())
-      return visit_continue_with_parent;
-
-   if (ir->lhs->as_dereference_variable() &&
-       ir->rhs->as_dereference_variable() &&
-       !ir->condition) {
-      /* We'll split copies of a structure to copies of components, so don't
-       * descend to the ir_dereference_variables.
-       */
-      return visit_continue_with_parent;
-   }
-   return visit_continue;
-}
-
-ir_visitor_status
-ir_structure_reference_visitor::visit_enter(ir_function_signature *ir)
-{
-   /* We don't want to descend into the function parameters and
-    * dead-code eliminate them, so just accept the body here.
-    */
-   visit_list_elements(this, &ir->body);
-   return visit_continue_with_parent;
-}
-
-class ir_structure_splitting_visitor : public ir_rvalue_visitor {
-public:
-   ir_structure_splitting_visitor(exec_list *vars)
-   {
-      this->variable_list = vars;
-   }
-
-   virtual ~ir_structure_splitting_visitor()
-   {
-   }
-
-   virtual ir_visitor_status visit_leave(ir_assignment *);
-
-   void split_deref(ir_dereference **deref);
-   void handle_rvalue(ir_rvalue **rvalue);
-   variable_entry2 *get_splitting_entry(ir_variable *var);
-
-   exec_list *variable_list;
-   void *mem_ctx;
-};
-
-variable_entry2 *
-ir_structure_splitting_visitor::get_splitting_entry(ir_variable *var)
-{
-   assert(var);
-
-   if (!var->type->is_record())
-      return NULL;
-
-   foreach_iter(exec_list_iterator, iter, *this->variable_list) {
-      variable_entry2 *entry = (variable_entry2 *)iter.get();
-      if (entry->var == var) {
-	 return entry;
-      }
-   }
-
-   return NULL;
-}
-
-void
-ir_structure_splitting_visitor::split_deref(ir_dereference **deref)
-{
-   if ((*deref)->ir_type != ir_type_dereference_record)
-      return;
-
-   ir_dereference_record *deref_record = (ir_dereference_record *)*deref;
-   ir_dereference_variable *deref_var = deref_record->record->as_dereference_variable();
-   if (!deref_var)
-      return;
-
-   variable_entry2 *entry = get_splitting_entry(deref_var->var);
-   if (!entry)
-      return;
-
-   unsigned int i;
-   for (i = 0; i < entry->var->type->length; i++) {
-      if (strcmp(deref_record->field,
-		 entry->var->type->fields.structure[i].name) == 0)
-	 break;
-   }
-   assert(i != entry->var->type->length);
-
-   *deref = new(entry->mem_ctx) ir_dereference_variable(entry->components[i]);
-}
-
-void
-ir_structure_splitting_visitor::handle_rvalue(ir_rvalue **rvalue)
-{
-   if (!*rvalue)
-      return;
-
-   ir_dereference *deref = (*rvalue)->as_dereference();
-
-   if (!deref)
-      return;
-
-   split_deref(&deref);
-   *rvalue = deref;
-}
-
-ir_visitor_status
-ir_structure_splitting_visitor::visit_leave(ir_assignment *ir)
-{
-   ir_dereference_variable *lhs_deref = ir->lhs->as_dereference_variable();
-   ir_dereference_variable *rhs_deref = ir->rhs->as_dereference_variable();
-   variable_entry2 *lhs_entry = lhs_deref ? get_splitting_entry(lhs_deref->var) : NULL;
-   variable_entry2 *rhs_entry = rhs_deref ? get_splitting_entry(rhs_deref->var) : NULL;
-   const glsl_type *type = ir->rhs->type;
-
-   if ((lhs_entry || rhs_entry) && !ir->condition) {
-      for (unsigned int i = 0; i < type->length; i++) {
-	 ir_dereference *new_lhs, *new_rhs;
-	 void *mem_ctx = lhs_entry ? lhs_entry->mem_ctx : rhs_entry->mem_ctx;
-
-	 if (lhs_entry) {
-	    new_lhs = new(mem_ctx) ir_dereference_variable(lhs_entry->components[i]);
-	 } else {
-	    new_lhs = new(mem_ctx)
-	       ir_dereference_record(ir->lhs->clone(mem_ctx, NULL),
-				     type->fields.structure[i].name);
-	 }
-
-	 if (rhs_entry) {
-	    new_rhs = new(mem_ctx) ir_dereference_variable(rhs_entry->components[i]);
-	 } else {
-	    new_rhs = new(mem_ctx)
-	       ir_dereference_record(ir->rhs->clone(mem_ctx, NULL),
-				     type->fields.structure[i].name);
-	 }
-
-	 ir->insert_before(new(mem_ctx) ir_assignment(new_lhs,
-						      new_rhs,
-						      NULL));
-      }
-      ir->remove();
-   } else {
-      handle_rvalue(&ir->rhs);
-      split_deref(&ir->lhs);
-   }
-
-   handle_rvalue(&ir->condition);
-
-   return visit_continue;
-}
-
-bool
-do_structure_splitting(exec_list *instructions)
-{
-   ir_structure_reference_visitor refs;
-
-   visit_list_elements(&refs, instructions);
-
-   /* Trim out variables we can't split. */
-   foreach_iter(exec_list_iterator, iter, refs.variable_list) {
-      variable_entry2 *entry = (variable_entry2 *)iter.get();
-
-      if (debug) {
-	 printf("structure %s@%p: decl %d, whole_access %d\n",
-		entry->var->name, (void *) entry->var, entry->declaration,
-		entry->whole_structure_access);
-      }
-
-      if (!entry->declaration || entry->whole_structure_access) {
-	 entry->remove();
-      }
-   }
-
-   if (refs.variable_list.is_empty())
-      return false;
-
-   void *mem_ctx = ralloc_context(NULL);
-
-   /* Replace the decls of the structures to be split with their split
-    * components.
-    */
-   foreach_iter(exec_list_iterator, iter, refs.variable_list) {
-      variable_entry2 *entry = (variable_entry2 *)iter.get();
-      const struct glsl_type *type = entry->var->type;
-
-      entry->mem_ctx = ralloc_parent(entry->var);
-
-      entry->components = ralloc_array(mem_ctx,
-				       ir_variable *,
-				       type->length);
-
-      for (unsigned int i = 0; i < entry->var->type->length; i++) {
-	 const char *name = ralloc_asprintf(mem_ctx, "%s_%s",
-					    entry->var->name,
-					    type->fields.structure[i].name);
-
-	 entry->components[i] =
-	    new(entry->mem_ctx) ir_variable(type->fields.structure[i].type,
-					    name,
-					    ir_var_temporary);
-	 entry->var->insert_before(entry->components[i]);
-      }
-
-      entry->var->remove();
-   }
-
-   ir_structure_splitting_visitor split(&refs.variable_list);
-   visit_list_elements(&split, instructions);
-
-   ralloc_free(mem_ctx);
-
-   return true;
-}
+/*
+ * 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.
+ */
+
+/**
+ * \file opt_structure_splitting.cpp
+ *
+ * If a structure is only ever referenced by its components, then
+ * split those components out to individual variables so they can be
+ * handled normally by other optimization passes.
+ *
+ * This skips structures like uniforms, which need to be accessible as
+ * structures for their access by the GL.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_print_visitor.h"
+#include "ir_rvalue_visitor.h"
+#include "glsl_types.h"
+
+static bool debug = false;
+
+// XXX using variable_entry2 here to avoid collision (MSVC multiply-defined
+// function) with the variable_entry class seen in ir_variable_refcount.h
+// Perhaps we can use the one in ir_variable_refcount.h and make this class
+// here go away?
+class variable_entry2 : public exec_node
+{
+public:
+   variable_entry2(ir_variable *var)
+   {
+      this->var = var;
+      this->whole_structure_access = 0;
+      this->declaration = false;
+      this->components = NULL;
+      this->mem_ctx = NULL;
+   }
+
+   ir_variable *var; /* The key: the variable's pointer. */
+
+   /** Number of times the variable is referenced, including assignments. */
+   unsigned whole_structure_access;
+
+   /* If the variable had a decl we can work with in the instruction
+    * stream.  We can't do splitting on function arguments, which
+    * don't get this variable set.
+    */
+   bool declaration;
+
+   ir_variable **components;
+
+   /** ralloc_parent(this->var) -- the shader's ralloc context. */
+   void *mem_ctx;
+};
+
+
+class ir_structure_reference_visitor : public ir_hierarchical_visitor {
+public:
+   ir_structure_reference_visitor(void)
+   {
+      this->mem_ctx = ralloc_context(NULL);
+      this->variable_list.make_empty();
+   }
+
+   ~ir_structure_reference_visitor(void)
+   {
+      ralloc_free(mem_ctx);
+   }
+
+   virtual ir_visitor_status visit(ir_variable *);
+   virtual ir_visitor_status visit(ir_dereference_variable *);
+   virtual ir_visitor_status visit_enter(ir_dereference_record *);
+   virtual ir_visitor_status visit_enter(ir_assignment *);
+   virtual ir_visitor_status visit_enter(ir_function_signature *);
+
+   variable_entry2 *get_variable_entry2(ir_variable *var);
+
+   /* List of variable_entry */
+   exec_list variable_list;
+
+   void *mem_ctx;
+};
+
+variable_entry2 *
+ir_structure_reference_visitor::get_variable_entry2(ir_variable *var)
+{
+   assert(var);
+
+   if (!var->type->is_record() || var->mode == ir_var_uniform)
+      return NULL;
+
+   foreach_iter(exec_list_iterator, iter, this->variable_list) {
+      variable_entry2 *entry = (variable_entry2 *)iter.get();
+      if (entry->var == var)
+	 return entry;
+   }
+
+   variable_entry2 *entry = new(mem_ctx) variable_entry2(var);
+   this->variable_list.push_tail(entry);
+   return entry;
+}
+
+
+ir_visitor_status
+ir_structure_reference_visitor::visit(ir_variable *ir)
+{
+   variable_entry2 *entry = this->get_variable_entry2(ir);
+
+   if (entry)
+      entry->declaration = true;
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_structure_reference_visitor::visit(ir_dereference_variable *ir)
+{
+   ir_variable *const var = ir->variable_referenced();
+   variable_entry2 *entry = this->get_variable_entry2(var);
+
+   if (entry)
+      entry->whole_structure_access++;
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_structure_reference_visitor::visit_enter(ir_dereference_record *ir)
+{
+   (void) ir;
+   /* Don't descend into the ir_dereference_variable below. */
+   return visit_continue_with_parent;
+}
+
+ir_visitor_status
+ir_structure_reference_visitor::visit_enter(ir_assignment *ir)
+{
+   /* If there are no structure references yet, no need to bother with
+    * processing the expression tree.
+    */
+   if (this->variable_list.is_empty())
+      return visit_continue_with_parent;
+
+   if (ir->lhs->as_dereference_variable() &&
+       ir->rhs->as_dereference_variable() &&
+       !ir->condition) {
+      /* We'll split copies of a structure to copies of components, so don't
+       * descend to the ir_dereference_variables.
+       */
+      return visit_continue_with_parent;
+   }
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_structure_reference_visitor::visit_enter(ir_function_signature *ir)
+{
+   /* We don't have logic for structure-splitting function arguments,
+    * so just look at the body instructions and not the parameter
+    * declarations.
+    */
+   visit_list_elements(this, &ir->body);
+   return visit_continue_with_parent;
+}
+
+class ir_structure_splitting_visitor : public ir_rvalue_visitor {
+public:
+   ir_structure_splitting_visitor(exec_list *vars)
+   {
+      this->variable_list = vars;
+   }
+
+   virtual ~ir_structure_splitting_visitor()
+   {
+   }
+
+   virtual ir_visitor_status visit_leave(ir_assignment *);
+
+   void split_deref(ir_dereference **deref);
+   void handle_rvalue(ir_rvalue **rvalue);
+   variable_entry2 *get_splitting_entry(ir_variable *var);
+
+   exec_list *variable_list;
+   void *mem_ctx;
+};
+
+variable_entry2 *
+ir_structure_splitting_visitor::get_splitting_entry(ir_variable *var)
+{
+   assert(var);
+
+   if (!var->type->is_record())
+      return NULL;
+
+   foreach_iter(exec_list_iterator, iter, *this->variable_list) {
+      variable_entry2 *entry = (variable_entry2 *)iter.get();
+      if (entry->var == var) {
+	 return entry;
+      }
+   }
+
+   return NULL;
+}
+
+void
+ir_structure_splitting_visitor::split_deref(ir_dereference **deref)
+{
+   if ((*deref)->ir_type != ir_type_dereference_record)
+      return;
+
+   ir_dereference_record *deref_record = (ir_dereference_record *)*deref;
+   ir_dereference_variable *deref_var = deref_record->record->as_dereference_variable();
+   if (!deref_var)
+      return;
+
+   variable_entry2 *entry = get_splitting_entry(deref_var->var);
+   if (!entry)
+      return;
+
+   unsigned int i;
+   for (i = 0; i < entry->var->type->length; i++) {
+      if (strcmp(deref_record->field,
+		 entry->var->type->fields.structure[i].name) == 0)
+	 break;
+   }
+   assert(i != entry->var->type->length);
+
+   *deref = new(entry->mem_ctx) ir_dereference_variable(entry->components[i]);
+}
+
+void
+ir_structure_splitting_visitor::handle_rvalue(ir_rvalue **rvalue)
+{
+   if (!*rvalue)
+      return;
+
+   ir_dereference *deref = (*rvalue)->as_dereference();
+
+   if (!deref)
+      return;
+
+   split_deref(&deref);
+   *rvalue = deref;
+}
+
+ir_visitor_status
+ir_structure_splitting_visitor::visit_leave(ir_assignment *ir)
+{
+   ir_dereference_variable *lhs_deref = ir->lhs->as_dereference_variable();
+   ir_dereference_variable *rhs_deref = ir->rhs->as_dereference_variable();
+   variable_entry2 *lhs_entry = lhs_deref ? get_splitting_entry(lhs_deref->var) : NULL;
+   variable_entry2 *rhs_entry = rhs_deref ? get_splitting_entry(rhs_deref->var) : NULL;
+   const glsl_type *type = ir->rhs->type;
+
+   if ((lhs_entry || rhs_entry) && !ir->condition) {
+      for (unsigned int i = 0; i < type->length; i++) {
+	 ir_dereference *new_lhs, *new_rhs;
+	 void *mem_ctx = lhs_entry ? lhs_entry->mem_ctx : rhs_entry->mem_ctx;
+
+	 if (lhs_entry) {
+	    new_lhs = new(mem_ctx) ir_dereference_variable(lhs_entry->components[i]);
+	 } else {
+	    new_lhs = new(mem_ctx)
+	       ir_dereference_record(ir->lhs->clone(mem_ctx, NULL),
+				     type->fields.structure[i].name);
+	 }
+
+	 if (rhs_entry) {
+	    new_rhs = new(mem_ctx) ir_dereference_variable(rhs_entry->components[i]);
+	 } else {
+	    new_rhs = new(mem_ctx)
+	       ir_dereference_record(ir->rhs->clone(mem_ctx, NULL),
+				     type->fields.structure[i].name);
+	 }
+
+	 ir->insert_before(new(mem_ctx) ir_assignment(new_lhs,
+						      new_rhs,
+						      NULL));
+      }
+      ir->remove();
+   } else {
+      handle_rvalue(&ir->rhs);
+      split_deref(&ir->lhs);
+   }
+
+   handle_rvalue(&ir->condition);
+
+   return visit_continue;
+}
+
+bool
+do_structure_splitting(exec_list *instructions)
+{
+   ir_structure_reference_visitor refs;
+
+   visit_list_elements(&refs, instructions);
+
+   /* Trim out variables we can't split. */
+   foreach_iter(exec_list_iterator, iter, refs.variable_list) {
+      variable_entry2 *entry = (variable_entry2 *)iter.get();
+
+      if (debug) {
+	 printf("structure %s@%p: decl %d, whole_access %d\n",
+		entry->var->name, (void *) entry->var, entry->declaration,
+		entry->whole_structure_access);
+      }
+
+      if (!entry->declaration || entry->whole_structure_access) {
+	 entry->remove();
+      }
+   }
+
+   if (refs.variable_list.is_empty())
+      return false;
+
+   void *mem_ctx = ralloc_context(NULL);
+
+   /* Replace the decls of the structures to be split with their split
+    * components.
+    */
+   foreach_iter(exec_list_iterator, iter, refs.variable_list) {
+      variable_entry2 *entry = (variable_entry2 *)iter.get();
+      const struct glsl_type *type = entry->var->type;
+
+      entry->mem_ctx = ralloc_parent(entry->var);
+
+      entry->components = ralloc_array(mem_ctx,
+				       ir_variable *,
+				       type->length);
+
+      for (unsigned int i = 0; i < entry->var->type->length; i++) {
+	 const char *name = ralloc_asprintf(mem_ctx, "%s_%s",
+					    entry->var->name,
+					    type->fields.structure[i].name);
+
+	 entry->components[i] =
+	    new(entry->mem_ctx) ir_variable(type->fields.structure[i].type,
+					    name,
+					    ir_var_temporary);
+	 entry->var->insert_before(entry->components[i]);
+      }
+
+      entry->var->remove();
+   }
+
+   ir_structure_splitting_visitor split(&refs.variable_list);
+   visit_list_elements(&split, instructions);
+
+   ralloc_free(mem_ctx);
+
+   return true;
+}