ir_function_can_inline.cpp

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file ir_function_can_inline.cpp
  26  *
  27  * Determines if we can inline a function call using ir_function_inlining.cpp.
  28  *
  29  * The primary restriction is that we can't return from the function
  30  * other than as the last instruction.  We could potentially work
  31  * around this for some constructs by flattening control flow and
  32  * moving the return to the end, or by using breaks from a do {} while
  33  * (0) loop surrounding the function body.
  34  */
  35
  36 #define NULL 0
  37 #include "ir.h"
  38 #include "ir_visitor.h"
  39 #include "ir_function_inlining.h"
  40 #include "ir_expression_flattening.h"
  41 #include "glsl_types.h"
  42
  43 class ir_function_can_inline_visitor : public ir_visitor {
  44 public:
  45    ir_function_can_inline_visitor()
  46    {
  47       this->can_inline = true;
  48       this->num_returns = 0;
  49    }
  50
  51    /**
  52     * \name Visit methods
  53     *
  54     * As typical for the visitor pattern, there must be one \c visit method for
  55     * each concrete subclass of \c ir_instruction.  Virtual base classes within
  56     * the hierarchy should not have \c visit methods.
  57     */
  58    /*@{*/
  59    virtual void visit(ir_variable *);
  60    virtual void visit(ir_label *);
  61    virtual void visit(ir_loop *);
  62    virtual void visit(ir_loop_jump *);
  63    virtual void visit(ir_function_signature *);
  64    virtual void visit(ir_function *);
  65    virtual void visit(ir_expression *);
  66    virtual void visit(ir_swizzle *);
  67    virtual void visit(ir_dereference *);
  68    virtual void visit(ir_assignment *);
  69    virtual void visit(ir_constant *);
  70    virtual void visit(ir_call *);
  71    virtual void visit(ir_return *);
  72    virtual void visit(ir_if *);
  73    /*@}*/
  74
  75    bool can_inline;
  76    int num_returns;
  77 };
  78
  79 void
  80 ir_function_can_inline_visitor::visit(ir_variable *ir)
  81 {
  82    (void)ir;
  83 }
  84
  85 void
  86 ir_function_can_inline_visitor::visit(ir_label *ir)
  87 {
  88    (void)ir;
  89 }
  90
  91 void
  92 ir_function_can_inline_visitor::visit(ir_loop *ir)
  93 {
  94    /* FINISHME: Implement loop cloning in ir_function_inlining.cpp */
  95    this->can_inline = false;
  96
  97    if (ir->from)
  98       ir->from->accept(this);
  99    if (ir->to)
 100       ir->to->accept(this);
 101    if (ir->increment)
 102       ir->increment->accept(this);
 103
 104    foreach_iter(exec_list_iterator, iter, ir->body_instructions) {
 105       ir_instruction *inner_ir = (ir_instruction *)iter.get();
 106       inner_ir->accept(this);
 107    }
 108 }
 109
 110 void
 111 ir_function_can_inline_visitor::visit(ir_loop_jump *ir)
 112 {
 113    (void) ir;
 114 }
 115
 116
 117 void
 118 ir_function_can_inline_visitor::visit(ir_function_signature *ir)
 119 {
 120    (void)ir;
 121 }
 122
 123
 124 void
 125 ir_function_can_inline_visitor::visit(ir_function *ir)
 126 {
 127    (void) ir;
 128 }
 129
 130 void
 131 ir_function_can_inline_visitor::visit(ir_expression *ir)
 132 {
 133    unsigned int operand;
 134
 135    for (operand = 0; operand < ir->get_num_operands(); operand++) {
 136       ir->operands[operand]->accept(this);
 137    }
 138 }
 139
 140
 141 void
 142 ir_function_can_inline_visitor::visit(ir_swizzle *ir)
 143 {
 144    ir->val->accept(this);
 145 }
 146
 147 void
 148 ir_function_can_inline_visitor::visit(ir_dereference *ir)
 149 {
 150    ir->var->accept(this);
 151    if (ir->mode == ir_dereference::ir_reference_array)
 152       ir->selector.array_index->accept(this);
 153 }
 154
 155 void
 156 ir_function_can_inline_visitor::visit(ir_assignment *ir)
 157 {
 158    ir->lhs->accept(this);
 159    ir->rhs->accept(this);
 160    if (ir->condition)
 161       ir->condition->accept(this);
 162 }
 163
 164
 165 void
 166 ir_function_can_inline_visitor::visit(ir_constant *ir)
 167 {
 168    (void)ir;
 169 }
 170
 171
 172 void
 173 ir_function_can_inline_visitor::visit(ir_call *ir)
 174 {
 175    foreach_iter(exec_list_iterator, iter, *ir) {
 176       ir_rvalue *param = (ir_rvalue *)iter.get();
 177
 178       param->accept(this);
 179    }
 180 }
 181
 182
 183 void
 184 ir_function_can_inline_visitor::visit(ir_return *ir)
 185 {
 186    ir->get_value()->accept(this);
 187
 188    this->num_returns++;
 189 }
 190
 191
 192 void
 193 ir_function_can_inline_visitor::visit(ir_if *ir)
 194 {
 195    /* FINISHME: Implement if cloning in ir_function_inlining.cpp. */
 196    this->can_inline = false;
 197
 198    ir->condition->accept(this);
 199
 200    foreach_iter(exec_list_iterator, iter, ir->then_instructions) {
 201       ir_instruction *inner_ir = (ir_instruction *)iter.get();
 202       inner_ir->accept(this);
 203    }
 204
 205    foreach_iter(exec_list_iterator, iter, ir->else_instructions) {
 206       ir_instruction *inner_ir = (ir_instruction *)iter.get();
 207       inner_ir->accept(this);
 208    }
 209 }
 210
 211 bool
 212 can_inline(ir_call *call)
 213 {
 214    ir_function_can_inline_visitor v;
 215    const ir_function_signature *callee = call->get_callee();
 216
 217    foreach_iter(exec_list_iterator, iter, callee->body) {
 218       ir_instruction *ir = (ir_instruction *)iter.get();
 219       ir->accept(&v);
 220    }
 221
 222    ir_instruction *last = (ir_instruction *)callee->body.get_tail();
 223    if (last && !last->as_return())
 224       v.num_returns++;
 225
 226    return v.can_inline && v.num_returns == 1;
 227 }