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Diffstat (limited to 'mesalib/src/glsl/ir_hierarchical_visitor.h')
| -rw-r--r-- | mesalib/src/glsl/ir_hierarchical_visitor.h | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/mesalib/src/glsl/ir_hierarchical_visitor.h b/mesalib/src/glsl/ir_hierarchical_visitor.h new file mode 100644 index 000000000..dc177f5eb --- /dev/null +++ b/mesalib/src/glsl/ir_hierarchical_visitor.h @@ -0,0 +1,183 @@ +/* -*- 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_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); + +#endif /* IR_HIERARCHICAL_VISITOR_H */ |