/* -*- 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. */ }; #ifdef __cplusplus /** * 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 *); virtual ir_visitor_status visit(class ir_emit_vertex *); virtual ir_visitor_status visit(class ir_end_primitive *); /** * 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 /* __cplusplus */ #endif /* IR_HIERARCHICAL_VISITOR_H */