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 "compiler/glsl_types.h"
31#include "glsl_parser_extras.h"
32#include "ir.h"
33#include "ir_builder.h"
34
35using namespace ir_builder;
36namespace {
37
38class lower_subroutine_visitor : public ir_hierarchical_visitor {
39public:
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   ir_call *call_clone(ir_call *call, ir_function_signature *callee);
48   bool progress;
49   struct _mesa_glsl_parse_state *state;
50};
51
52}
53
54bool
55lower_subroutine(exec_list *instructions, struct _mesa_glsl_parse_state *state)
56{
57   lower_subroutine_visitor v(state);
58   visit_list_elements(&v, instructions);
59   return v.progress;
60}
61
62ir_call *
63lower_subroutine_visitor::call_clone(ir_call *call, ir_function_signature *callee)
64{
65   void *mem_ctx = ralloc_parent(call);
66   ir_dereference_variable *new_return_ref = NULL;
67   if (call->return_deref != NULL)
68      new_return_ref = call->return_deref->clone(mem_ctx, NULL);
69
70   exec_list new_parameters;
71
72   foreach_in_list(ir_instruction, ir, &call->actual_parameters) {
73      new_parameters.push_tail(ir->clone(mem_ctx, NULL));
74   }
75
76   return new(mem_ctx) ir_call(callee, new_return_ref, &new_parameters);
77}
78
79ir_visitor_status
80lower_subroutine_visitor::visit_leave(ir_call *ir)
81{
82   if (!ir->sub_var)
83      return visit_continue;
84
85   void *mem_ctx = ralloc_parent(ir);
86   ir_if *last_branch = NULL;
87
88   for (int s = this->state->num_subroutines - 1; s >= 0; s--) {
89      ir_rvalue *var;
90      ir_function *fn = this->state->subroutines[s];
91      ir_constant *lc = new(mem_ctx)ir_constant(fn->subroutine_index);
92
93      bool is_compat = false;
94
95      for (int i = 0; i < fn->num_subroutine_types; i++) {
96         if (ir->sub_var->type->without_array() == fn->subroutine_types[i]) {
97            is_compat = true;
98            break;
99         }
100      }
101      if (is_compat == false)
102         continue;
103
104      if (ir->array_idx != NULL)
105         var = ir->array_idx->clone(mem_ctx, NULL);
106      else
107         var = new(mem_ctx) ir_dereference_variable(ir->sub_var);
108
109      ir_function_signature *sub_sig =
110         fn->exact_matching_signature(this->state,
111                                      &ir->actual_parameters);
112
113      ir_call *new_call = call_clone(ir, sub_sig);
114      if (!last_branch)
115         last_branch = if_tree(equal(subr_to_int(var), lc), new_call);
116      else
117         last_branch = if_tree(equal(subr_to_int(var), lc), new_call, last_branch);
118   }
119   if (last_branch)
120      ir->insert_before(last_branch);
121   ir->remove();
122
123   return visit_continue;
124}
125