146 lines
4.5 KiB
C++
146 lines
4.5 KiB
C++
/*
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* Copyright © 2010 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file ir_basic_block.cpp
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*
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* Basic block analysis of instruction streams.
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*/
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#include <stdio.h>
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#include "ir.h"
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#include "ir_visitor.h"
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#include "ir_basic_block.h"
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#include "glsl_types.h"
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class ir_has_call_visitor : public ir_hierarchical_visitor {
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public:
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ir_has_call_visitor()
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{
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has_call = false;
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}
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virtual ir_visitor_status visit_enter(ir_call *ir)
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{
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(void) ir;
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has_call = true;
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return visit_stop;
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}
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bool has_call;
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};
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/**
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* Calls a user function for every basic block in the instruction stream.
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*
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* Basic block analysis is pretty easy in our IR thanks to the lack of
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* unstructured control flow. We've got:
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*
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* ir_loop (for () {}, while () {}, do {} while ())
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* ir_loop_jump (
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* ir_if () {}
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* ir_return
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* ir_call()
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*
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* Note that the basic blocks returned by this don't encompass all
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* operations performed by the program -- for example, if conditions
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* don't get returned, nor do the assignments that will be generated
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* for ir_call parameters.
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*/
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void call_for_basic_blocks(exec_list *instructions,
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void (*callback)(ir_instruction *first,
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ir_instruction *last,
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void *data),
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void *data)
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{
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ir_instruction *leader = NULL;
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ir_instruction *last = NULL;
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foreach_iter(exec_list_iterator, iter, *instructions) {
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ir_instruction *ir = (ir_instruction *)iter.get();
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ir_if *ir_if;
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ir_loop *ir_loop;
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ir_function *ir_function;
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if (!leader)
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leader = ir;
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if ((ir_if = ir->as_if())) {
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callback(leader, ir, data);
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leader = NULL;
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call_for_basic_blocks(&ir_if->then_instructions, callback, data);
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call_for_basic_blocks(&ir_if->else_instructions, callback, data);
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} else if ((ir_loop = ir->as_loop())) {
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callback(leader, ir, data);
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leader = NULL;
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call_for_basic_blocks(&ir_loop->body_instructions, callback, data);
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} else if (ir->as_return() || ir->as_call()) {
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callback(leader, ir, data);
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leader = NULL;
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} else if ((ir_function = ir->as_function())) {
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/* A function definition doesn't interrupt our basic block
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* since execution doesn't go into it. We should process the
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* bodies of its signatures for BBs, though.
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*
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* Note that we miss an opportunity for producing more
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* maximal BBs between the instructions that precede main()
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* and the body of main(). Perhaps those instructions ought
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* to live inside of main().
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*/
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foreach_iter(exec_list_iterator, fun_iter, *ir_function) {
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ir_function_signature *ir_sig;
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ir_sig = (ir_function_signature *)fun_iter.get();
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call_for_basic_blocks(&ir_sig->body, callback, data);
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}
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} else if (ir->as_assignment()) {
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ir_has_call_visitor v;
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/* If there's a call in the expression tree being assigned,
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* then that ends the BB too.
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*
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* The assumption is that any consumer of the basic block
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* walker is fine with the fact that the call is somewhere in
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* the tree even if portions of the tree may be evaluated
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* after the call.
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*
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* A consumer that has an issue with this could not process
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* the last instruction of the basic block. If doing so,
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* expression flattener may be useful before using the basic
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* block finder to get more maximal basic blocks out.
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*/
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ir->accept(&v);
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if (v.has_call) {
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callback(leader, ir, data);
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leader = NULL;
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}
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}
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last = ir;
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}
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if (leader) {
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callback(leader, last, data);
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}
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}
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