glsl: move to compiler/

Signed-off-by: Emil Velikov <[email protected]>
Acked-by: Matt Turner <[email protected]>
Acked-by: Jose Fonseca <[email protected]>

1 files changed, 408 insertions, 0 deletions

diff --git a/src/compiler/glsl/opt_array_splitting.cpp b/src/compiler/glsl/opt_array_splitting.cpp
new file mode 100644
index 00000000000..cceec6b6431
--- /dev/null
+++ b/src/compiler/glsl/opt_array_splitting.cpp
@@ -0,0 +1,408 @@
+/*
+ * 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_array_splitting.cpp
+ *
+ * If an array is always dereferenced with a constant index, then
+ * split it apart into its elements, making it more amenable to other
+ * optimization passes.
+ *
+ * This skips uniform/varying arrays, which would need careful
+ * handling due to their ir->location fields tying them to the GL API
+ * and other shader stages.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_rvalue_visitor.h"
+#include "compiler/glsl_types.h"
+
+static bool debug = false;
+
+namespace {
+
+namespace opt_array_splitting {
+
+class variable_entry : public exec_node
+{
+public:
+   variable_entry(ir_variable *var)
+   {
+      this->var = var;
+      this->split = true;
+      this->declaration = false;
+      this->components = NULL;
+      this->mem_ctx = NULL;
+      if (var->type->is_array())
+	 this->size = var->type->length;
+      else
+	 this->size = var->type->matrix_columns;
+   }
+
+   ir_variable *var; /* The key: the variable's pointer. */
+   unsigned size; /* array length or matrix columns */
+
+   /** Whether this array should be split or not. */
+   bool split;
+
+   /* 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 talloc context. */
+   void *mem_ctx;
+};
+
+} /* namespace */
+
+using namespace opt_array_splitting;
+
+/**
+ * This class does a walk over the tree, coming up with the set of
+ * variables that could be split by looking to see if they are arrays
+ * that are only ever constant-index dereferenced.
+ */
+class ir_array_reference_visitor : public ir_hierarchical_visitor {
+public:
+   ir_array_reference_visitor(void)
+   {
+      this->mem_ctx = ralloc_context(NULL);
+      this->variable_list.make_empty();
+   }
+
+   ~ir_array_reference_visitor(void)
+   {
+      ralloc_free(mem_ctx);
+   }
+
+   bool get_split_list(exec_list *instructions, bool linked);
+
+   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);
+
+   /* List of variable_entry */
+   exec_list variable_list;
+
+   void *mem_ctx;
+};
+
+} /* namespace */
+
+variable_entry *
+ir_array_reference_visitor::get_variable_entry(ir_variable *var)
+{
+   assert(var);
+
+   if (var->data.mode != ir_var_auto &&
+       var->data.mode != ir_var_temporary)
+      return NULL;
+
+   if (!(var->type->is_array() || var->type->is_matrix()))
+      return NULL;
+
+   /* If the array hasn't been sized yet, we can't split it.  After
+    * linking, this should be resolved.
+    */
+   if (var->type->is_unsized_array())
+      return NULL;
+
+   foreach_in_list(variable_entry, entry, &this->variable_list) {
+      if (entry->var == var)
+	 return entry;
+   }
+
+   variable_entry *entry = new(mem_ctx) variable_entry(var);
+   this->variable_list.push_tail(entry);
+   return entry;
+}
+
+
+ir_visitor_status
+ir_array_reference_visitor::visit(ir_variable *ir)
+{
+   variable_entry *entry = this->get_variable_entry(ir);
+
+   if (entry)
+      entry->declaration = true;
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_array_reference_visitor::visit(ir_dereference_variable *ir)
+{
+   variable_entry *entry = this->get_variable_entry(ir->var);
+
+   /* 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->split = false;
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_array_reference_visitor::visit_enter(ir_dereference_array *ir)
+{
+   ir_dereference_variable *deref = ir->array->as_dereference_variable();
+   if (!deref)
+      return visit_continue;
+
+   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->split = false;
+
+   /* If the index is also array dereference, visit index. */
+   if (ir->array_index->as_dereference_array())
+      visit_enter(ir->array_index->as_dereference_array());
+
+   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)
+{
+   visit_list_elements(this, instructions);
+
+   /* If the shaders aren't linked yet, we can't mess with global
+    * declarations, which need to be matched by name across shaders.
+    */
+   if (!linked) {
+      foreach_in_list(ir_instruction, node, instructions) {
+	 ir_variable *var = node->as_variable();
+	 if (var) {
+	    variable_entry *entry = get_variable_entry(var);
+	    if (entry)
+	       entry->remove();
+	 }
+      }
+   }
+
+   /* Trim out variables we found that we can't split. */
+   foreach_in_list_safe(variable_entry, entry, &variable_list) {
+      if (debug) {
+	 printf("array %s@%p: decl %d, split %d\n",
+		entry->var->name, (void *) entry->var, entry->declaration,
+		entry->split);
+      }
+
+      if (!(entry->declaration && entry->split)) {
+	 entry->remove();
+      }
+   }
+
+   return !variable_list.is_empty();
+}
+
+/**
+ * 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)
+   {
+      this->variable_list = vars;
+   }
+
+   virtual ~ir_array_splitting_visitor()
+   {
+   }
+
+   virtual ir_visitor_status visit_leave(ir_assignment *);
+
+   void split_deref(ir_dereference **deref);
+   void handle_rvalue(ir_rvalue **rvalue);
+   variable_entry *get_splitting_entry(ir_variable *var);
+
+   exec_list *variable_list;
+};
+
+variable_entry *
+ir_array_splitting_visitor::get_splitting_entry(ir_variable *var)
+{
+   assert(var);
+
+   foreach_in_list(variable_entry, entry, this->variable_list) {
+      if (entry->var == var) {
+	 return entry;
+      }
+   }
+
+   return NULL;
+}
+
+void
+ir_array_splitting_visitor::split_deref(ir_dereference **deref)
+{
+   ir_dereference_array *deref_array = (*deref)->as_dereference_array();
+   if (!deref_array)
+      return;
+
+   ir_dereference_variable *deref_var = deref_array->array->as_dereference_variable();
+   if (!deref_var)
+      return;
+   ir_variable *var = deref_var->var;
+
+   variable_entry *entry = get_splitting_entry(var);
+   if (!entry)
+      return;
+
+   ir_constant *constant = deref_array->array_index->as_constant();
+   assert(constant);
+
+   if (constant->value.i[0] >= 0 && constant->value.i[0] < (int)entry->size) {
+      *deref = new(entry->mem_ctx)
+	 ir_dereference_variable(entry->components[constant->value.i[0]]);
+   } else {
+      /* There was a constant array access beyond the end of the
+       * array.  This might have happened due to constant folding
+       * after the initial parse.  This produces an undefined value,
+       * but shouldn't crash.  Just give them an uninitialized
+       * variable.
+       */
+      ir_variable *temp = new(entry->mem_ctx) ir_variable(deref_array->type,
+							  "undef",
+							  ir_var_temporary);
+      entry->components[0]->insert_before(temp);
+      *deref = new(entry->mem_ctx) ir_dereference_variable(temp);
+   }
+}
+
+void
+ir_array_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_array_splitting_visitor::visit_leave(ir_assignment *ir)
+{
+   /* The normal rvalue visitor skips the LHS of assignments, but we
+    * need to process those just the same.
+    */
+   ir_rvalue *lhs = ir->lhs;
+
+   handle_rvalue(&lhs);
+   ir->lhs = lhs->as_dereference();
+
+   ir->lhs->accept(this);
+
+   handle_rvalue(&ir->rhs);
+   ir->rhs->accept(this);
+
+   if (ir->condition) {
+      handle_rvalue(&ir->condition);
+      ir->condition->accept(this);
+   }
+
+   return visit_continue;
+}
+
+bool
+optimize_split_arrays(exec_list *instructions, bool linked)
+{
+   ir_array_reference_visitor refs;
+   if (!refs.get_split_list(instructions, linked))
+      return false;
+
+   void *mem_ctx = ralloc_context(NULL);
+
+   /* Replace the decls of the arrays to be split with their split
+    * components.
+    */
+   foreach_in_list(variable_entry, entry, &refs.variable_list) {
+      const struct glsl_type *type = entry->var->type;
+      const struct glsl_type *subtype;
+
+      if (type->is_matrix())
+	 subtype = type->column_type();
+      else
+	 subtype = type->fields.array;
+
+      entry->mem_ctx = ralloc_parent(entry->var);
+
+      entry->components = ralloc_array(mem_ctx,
+				       ir_variable *,
+				       entry->size);
+
+      for (unsigned int i = 0; i < entry->size; i++) {
+	 const char *name = ralloc_asprintf(mem_ctx, "%s_%d",
+					    entry->var->name, i);
+
+	 entry->components[i] =
+	    new(entry->mem_ctx) ir_variable(subtype, name, ir_var_temporary);
+	 entry->var->insert_before(entry->components[i]);
+      }
+
+      entry->var->remove();
+   }
+
+   ir_array_splitting_visitor split(&refs.variable_list);
+   visit_list_elements(&split, instructions);
+
+   if (debug)
+      _mesa_print_ir(stdout, instructions, NULL);
+
+   ralloc_free(mem_ctx);
+
+   return true;
+
+}