src/glsl/lower_subroutine.cpp

   1 /*
   2  * Copyright © 2015 Red Hat
   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 lower_subroutine.cpp
  26  *
  27  * lowers subroutines to an if ladder.
  28  */
  29
  30 #include "glsl_types.h"
  31 #include "glsl_parser_extras.h"
  32 #include "ir.h"
  33 #include "ir_builder.h"
  34
  35 using namespace ir_builder;
  36 namespace {
  37
  38 class lower_subroutine_visitor : public ir_hierarchical_visitor {
  39 public:
  40    lower_subroutine_visitor(struct _mesa_glsl_parse_state *state)
  41       : state(state)
  42    {
  43       this->progress = false;
  44    }
  45
  46    ir_visitor_status visit_leave(ir_call *);
  47    bool progress;
  48    struct _mesa_glsl_parse_state *state;
  49 };
  50
  51 }
  52
  53 bool
  54 lower_subroutine(exec_list *instructions, struct _mesa_glsl_parse_state *state)
  55 {
  56    lower_subroutine_visitor v(state);
  57    visit_list_elements(&v, instructions);
  58    return v.progress;
  59 }
  60
  61 ir_visitor_status
  62 lower_subroutine_visitor::visit_leave(ir_call *ir)
  63 {
  64    if (!ir->sub_var)
  65       return visit_continue;
  66
  67    void *mem_ctx = ralloc_parent(ir);
  68    ir_if *last_branch = NULL;
  69    ir_dereference_variable *return_deref = ir->return_deref;
  70
  71    for (int s = this->state->num_subroutines - 1; s >= 0; s--) {
  72       ir_rvalue *var;
  73       ir_constant *lc = new(mem_ctx)ir_constant(s);
  74       ir_function *fn = this->state->subroutines[s];
  75       bool is_compat = false;
  76
  77       for (int i = 0; i < fn->num_subroutine_types; i++) {
  78          if (ir->sub_var->type->without_array() == fn->subroutine_types[i]) {
  79             is_compat = true;
  80             break;
  81          }
  82       }
  83       if (is_compat == false)
  84          continue;
  85
  86       if (ir->array_idx != NULL)
  87          var = new(mem_ctx) ir_dereference_array(ir->sub_var, ir->array_idx->clone(mem_ctx, NULL));
  88       else
  89          var = new(mem_ctx) ir_dereference_variable(ir->sub_var);
  90
  91       ir_function_signature *sub_sig =
  92          fn->exact_matching_signature(this->state,
  93                                       &ir->actual_parameters);
  94
  95       ir_call *new_call = new(mem_ctx) ir_call(sub_sig, return_deref, &ir->actual_parameters);
  96       if (!last_branch)
  97          last_branch = if_tree(equal(subr_to_int(var), lc), new_call);
  98       else
  99          last_branch = if_tree(equal(subr_to_int(var), lc), new_call, last_branch);
 100
 101       if (return_deref && s > 0)
 102         return_deref = return_deref->clone(mem_ctx, NULL);
 103    }
 104    if (last_branch)
 105       ir->insert_before(last_branch);
 106    ir->remove();
 107
 108    return visit_continue;
 109 }