| /* -*- c++ -*- */ |
| /* |
| * 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. |
| */ |
| |
| #pragma once |
| #ifndef IR_HIERARCHICAL_VISITOR_H |
| #define IR_HIERARCHICAL_VISITOR_H |
| |
| /** |
| * Enumeration values returned by visit methods to guide processing |
| */ |
| enum ir_visitor_status { |
| visit_continue, /**< Continue visiting as normal. */ |
| visit_continue_with_parent, /**< Don't visit siblings, continue w/parent. */ |
| visit_stop /**< Stop visiting immediately. */ |
| }; |
| |
| |
| /** |
| * Base class of hierarchical visitors of IR instruction trees |
| * |
| * Hierarchical visitors differ from traditional visitors in a couple of |
| * important ways. Rather than having a single \c visit method for each |
| * subclass in the composite, there are three kinds of visit methods. |
| * Leaf-node classes have a traditional \c visit method. Internal-node |
| * classes have a \c visit_enter method, which is invoked just before |
| * processing child nodes, and a \c visit_leave method which is invoked just |
| * after processing child nodes. |
| * |
| * In addition, each visit method and the \c accept methods in the composite |
| * have a return value which guides the navigation. Any of the visit methods |
| * can choose to continue visiting the tree as normal (by returning \c |
| * visit_continue), terminate visiting any further nodes immediately (by |
| * returning \c visit_stop), or stop visiting sibling nodes (by returning \c |
| * visit_continue_with_parent). |
| * |
| * These two changes combine to allow nagivation of children to be implemented |
| * in the composite's \c accept method. The \c accept method for a leaf-node |
| * class will simply call the \c visit method, as usual, and pass its return |
| * value on. The \c accept method for internal-node classes will call the \c |
| * visit_enter method, call the \c accpet method of each child node, and, |
| * finally, call the \c visit_leave method. If any of these return a value |
| * other that \c visit_continue, the correct action must be taken. |
| * |
| * The final benefit is that the hierarchical visitor base class need not be |
| * abstract. Default implementations of every \c visit, \c visit_enter, and |
| * \c visit_leave method can be provided. By default each of these methods |
| * simply returns \c visit_continue. This allows a significant reduction in |
| * derived class code. |
| * |
| * For more information about hierarchical visitors, see: |
| * |
| * http://c2.com/cgi/wiki?HierarchicalVisitorPattern |
| * http://c2.com/cgi/wiki?HierarchicalVisitorDiscussion |
| */ |
| |
| class ir_hierarchical_visitor { |
| public: |
| ir_hierarchical_visitor(); |
| |
| /** |
| * \name Visit methods for leaf-node classes |
| */ |
| /*@{*/ |
| virtual ir_visitor_status visit(class ir_rvalue *); |
| virtual ir_visitor_status visit(class ir_variable *); |
| virtual ir_visitor_status visit(class ir_constant *); |
| virtual ir_visitor_status visit(class ir_loop_jump *); |
| |
| /** |
| * ir_dereference_variable isn't technically a leaf, but it is treated as a |
| * leaf here for a couple reasons. By not automatically visiting the one |
| * child ir_variable node from the ir_dereference_variable, ir_variable |
| * nodes can always be handled as variable declarations. Code that used |
| * non-hierarchical visitors had to set an "in a dereference" flag to |
| * determine how to handle an ir_variable. By forcing the visitor to |
| * handle the ir_variable within the ir_dereference_variable visitor, this |
| * kludge can be avoided. |
| * |
| * In addition, I can envision no use for having separate enter and leave |
| * methods. Anything that could be done in the enter and leave methods |
| * that couldn't just be done in the visit method. |
| */ |
| virtual ir_visitor_status visit(class ir_dereference_variable *); |
| /*@}*/ |
| |
| /** |
| * \name Visit methods for internal-node classes |
| */ |
| /*@{*/ |
| virtual ir_visitor_status visit_enter(class ir_loop *); |
| virtual ir_visitor_status visit_leave(class ir_loop *); |
| virtual ir_visitor_status visit_enter(class ir_function_signature *); |
| virtual ir_visitor_status visit_leave(class ir_function_signature *); |
| virtual ir_visitor_status visit_enter(class ir_function *); |
| virtual ir_visitor_status visit_leave(class ir_function *); |
| virtual ir_visitor_status visit_enter(class ir_expression *); |
| virtual ir_visitor_status visit_leave(class ir_expression *); |
| virtual ir_visitor_status visit_enter(class ir_texture *); |
| virtual ir_visitor_status visit_leave(class ir_texture *); |
| virtual ir_visitor_status visit_enter(class ir_swizzle *); |
| virtual ir_visitor_status visit_leave(class ir_swizzle *); |
| virtual ir_visitor_status visit_enter(class ir_dereference_array *); |
| virtual ir_visitor_status visit_leave(class ir_dereference_array *); |
| virtual ir_visitor_status visit_enter(class ir_dereference_record *); |
| virtual ir_visitor_status visit_leave(class ir_dereference_record *); |
| virtual ir_visitor_status visit_enter(class ir_assignment *); |
| virtual ir_visitor_status visit_leave(class ir_assignment *); |
| virtual ir_visitor_status visit_enter(class ir_call *); |
| virtual ir_visitor_status visit_leave(class ir_call *); |
| virtual ir_visitor_status visit_enter(class ir_return *); |
| virtual ir_visitor_status visit_leave(class ir_return *); |
| virtual ir_visitor_status visit_enter(class ir_discard *); |
| virtual ir_visitor_status visit_leave(class ir_discard *); |
| virtual ir_visitor_status visit_enter(class ir_if *); |
| virtual ir_visitor_status visit_leave(class ir_if *); |
| /*@}*/ |
| |
| |
| /** |
| * Utility function to process a linked list of instructions with a visitor |
| */ |
| void run(struct exec_list *instructions); |
| |
| /* Some visitors may need to insert new variable declarations and |
| * assignments for portions of a subtree, which means they need a |
| * pointer to the current instruction in the stream, not just their |
| * node in the tree rooted at that instruction. |
| * |
| * This is implemented by visit_list_elements -- if the visitor is |
| * not called by it, nothing good will happen. |
| */ |
| class ir_instruction *base_ir; |
| |
| /** |
| * Callback function that is invoked on entry to each node visited. |
| * |
| * \warning |
| * Visitor classes derived from \c ir_hierarchical_visitor \b may \b not |
| * invoke this function. This can be used, for example, to cause the |
| * callback to be invoked on every node type execpt one. |
| */ |
| void (*callback)(class ir_instruction *ir, void *data); |
| |
| /** |
| * Extra data parameter passed to the per-node callback function |
| */ |
| void *data; |
| |
| /** |
| * Currently in the LHS of an assignment? |
| * |
| * This is set and cleared by the \c ir_assignment::accept method. |
| */ |
| bool in_assignee; |
| }; |
| |
| void visit_tree(ir_instruction *ir, |
| void (*callback)(class ir_instruction *ir, void *data), |
| void *data); |
| |
| ir_visitor_status visit_list_elements(ir_hierarchical_visitor *v, exec_list *l, |
| bool statement_list = true); |
| |
| #endif /* IR_HIERARCHICAL_VISITOR_H */ |