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Diffstat (limited to 'src/glsl/ir_basic_block.cpp')
| -rw-r--r-- | src/glsl/ir_basic_block.cpp | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/src/glsl/ir_basic_block.cpp b/src/glsl/ir_basic_block.cpp new file mode 100644 index 00000000000..f9953ea42da --- /dev/null +++ b/src/glsl/ir_basic_block.cpp @@ -0,0 +1,144 @@ +/* + * 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 ir_basic_block.cpp + * + * Basic block analysis of instruction streams. + */ + +#include "ir.h" +#include "ir_visitor.h" +#include "ir_basic_block.h" +#include "glsl_types.h" + +class ir_has_call_visitor : public ir_hierarchical_visitor { +public: + ir_has_call_visitor() + { + has_call = false; + } + + virtual ir_visitor_status visit_enter(ir_call *ir) + { + (void) ir; + has_call = true; + return visit_stop; + } + + bool has_call; +}; + +/** + * Calls a user function for every basic block in the instruction stream. + * + * Basic block analysis is pretty easy in our IR thanks to the lack of + * unstructured control flow. We've got: + * + * ir_loop (for () {}, while () {}, do {} while ()) + * ir_loop_jump ( + * ir_if () {} + * ir_return + * ir_call() + * + * Note that the basic blocks returned by this don't encompass all + * operations performed by the program -- for example, if conditions + * don't get returned, nor do the assignments that will be generated + * for ir_call parameters. + */ +void call_for_basic_blocks(exec_list *instructions, + void (*callback)(ir_instruction *first, + ir_instruction *last, + void *data), + void *data) +{ + ir_instruction *leader = NULL; + ir_instruction *last = NULL; + + foreach_iter(exec_list_iterator, iter, *instructions) { + ir_instruction *ir = (ir_instruction *)iter.get(); + ir_if *ir_if; + ir_loop *ir_loop; + ir_function *ir_function; + + if (!leader) + leader = ir; + + if ((ir_if = ir->as_if())) { + callback(leader, ir, data); + leader = NULL; + + call_for_basic_blocks(&ir_if->then_instructions, callback, data); + call_for_basic_blocks(&ir_if->else_instructions, callback, data); + } else if ((ir_loop = ir->as_loop())) { + callback(leader, ir, data); + leader = NULL; + call_for_basic_blocks(&ir_loop->body_instructions, callback, data); + } else if (ir->as_return() || ir->as_call()) { + callback(leader, ir, data); + leader = NULL; + } else if ((ir_function = ir->as_function())) { + /* A function definition doesn't interrupt our basic block + * since execution doesn't go into it. We should process the + * bodies of its signatures for BBs, though. + * + * Note that we miss an opportunity for producing more + * maximal BBs between the instructions that precede main() + * and the body of main(). Perhaps those instructions ought + * to live inside of main(). + */ + foreach_iter(exec_list_iterator, fun_iter, *ir_function) { + ir_function_signature *ir_sig; + + ir_sig = (ir_function_signature *)fun_iter.get(); + + call_for_basic_blocks(&ir_sig->body, callback, data); + } + } else if (ir->as_assignment()) { + ir_has_call_visitor v; + + /* If there's a call in the expression tree being assigned, + * then that ends the BB too. + * + * The assumption is that any consumer of the basic block + * walker is fine with the fact that the call is somewhere in + * the tree even if portions of the tree may be evaluated + * after the call. + * + * A consumer that has an issue with this could not process + * the last instruction of the basic block. If doing so, + * expression flattener may be useful before using the basic + * block finder to get more maximal basic blocks out. + */ + ir->accept(&v); + if (v.has_call) { + callback(leader, ir, data); + leader = NULL; + } + } + last = ir; + } + if (leader) { + callback(leader, last, data); + } +} |