src/glsl/ir_set_program_inouts.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_set_program_inouts.cpp
  26  *
  27  * Sets the InputsRead and OutputsWritten of Mesa programs.
  28  *
  29  * Mesa programs (gl_program, not gl_shader_program) have a set of
  30  * flags indicating which varyings are read and written.  Computing
  31  * which are actually read from some sort of backend code can be
  32  * tricky when variable array indexing involved.  So this pass
  33  * provides support for setting InputsRead and OutputsWritten right
  34  * from the GLSL IR.
  35  */
  36
  37 #include "main/core.h" /* for struct gl_program */
  38 #include "program/hash_table.h"
  39 #include "ir.h"
  40 #include "ir_visitor.h"
  41 #include "glsl_types.h"
  42
  43 class ir_set_program_inouts_visitor : public ir_hierarchical_visitor {
  44 public:
  45    ir_set_program_inouts_visitor(struct gl_program *prog)
  46    {
  47       this->prog = prog;
  48       this->ht = hash_table_ctor(0,
  49                                  hash_table_pointer_hash,
  50                                  hash_table_pointer_compare);
  51    }
  52    ~ir_set_program_inouts_visitor()
  53    {
  54       hash_table_dtor(this->ht);
  55    }
  56
  57    virtual ir_visitor_status visit_enter(ir_dereference_array *);
  58    virtual ir_visitor_status visit_enter(ir_function_signature *);
  59    virtual ir_visitor_status visit(ir_dereference_variable *);
  60    virtual ir_visitor_status visit(ir_variable *);
  61
  62    struct gl_program *prog;
  63    struct hash_table *ht;
  64 };
  65
  66 static void
  67 mark(struct gl_program *prog, ir_variable *var, int offset, int len)
  68 {
  69    /* As of GLSL 1.20, varyings can only be floats, floating-point
  70     * vectors or matrices, or arrays of them.  For Mesa programs using
  71     * InputsRead/OutputsWritten, everything but matrices uses one
  72     * slot, while matrices use a slot per column.  Presumably
  73     * something doing a more clever packing would use something other
  74     * than InputsRead/OutputsWritten.
  75     */
  76
  77    for (int i = 0; i < len; i++) {
  78       if (var->mode == ir_var_in)
  79          prog->InputsRead |= BITFIELD64_BIT(var->location + offset + i);
  80       else if (var->mode == ir_var_system_value)
  81          prog->SystemValuesRead |= (1 << (var->location + offset + i));
  82       else
  83          prog->OutputsWritten |= BITFIELD64_BIT(var->location + offset + i);
  84    }
  85 }
  86
  87 /* Default handler: Mark all the locations in the variable as used. */
  88 ir_visitor_status
  89 ir_set_program_inouts_visitor::visit(ir_dereference_variable *ir)
  90 {
  91    if (hash_table_find(this->ht, ir->var) == NULL)
  92       return visit_continue;
  93
  94    if (ir->type->is_array()) {
  95       mark(this->prog, ir->var, 0,
  96            ir->type->length * ir->type->fields.array->matrix_columns);
  97    } else {
  98       mark(this->prog, ir->var, 0, ir->type->matrix_columns);
  99    }
 100
 101    return visit_continue;
 102 }
 103
 104 ir_visitor_status
 105 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
 106 {
 107    ir_dereference_variable *deref_var;
 108    ir_constant *index = ir->array_index->as_constant();
 109    deref_var = ir->array->as_dereference_variable();
 110    ir_variable *var = NULL;
 111
 112    /* Check that we're dereferencing a shader in or out */
 113    if (deref_var)
 114       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
 115
 116    if (index && var) {
 117       int width = 1;
 118
 119       if (deref_var->type->is_array() &&
 120           deref_var->type->fields.array->is_matrix()) {
 121          width = deref_var->type->fields.array->matrix_columns;
 122       }
 123
 124       mark(this->prog, var, index->value.i[0] * width, width);
 125       return visit_continue_with_parent;
 126    }
 127
 128    return visit_continue;
 129 }
 130
 131 ir_visitor_status
 132 ir_set_program_inouts_visitor::visit(ir_variable *ir)
 133 {
 134    if (ir->mode == ir_var_in ||
 135        ir->mode == ir_var_out ||
 136        ir->mode == ir_var_system_value) {
 137       hash_table_insert(this->ht, ir, ir);
 138    }
 139
 140    return visit_continue;
 141 }
 142
 143 ir_visitor_status
 144 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
 145 {
 146    /* We don't want to descend into the function parameters and
 147     * consider them as shader inputs or outputs.
 148     */
 149    visit_list_elements(this, &ir->body);
 150    return visit_continue_with_parent;
 151 }
 152
 153 void
 154 do_set_program_inouts(exec_list *instructions, struct gl_program *prog)
 155 {
 156    ir_set_program_inouts_visitor v(prog);
 157
 158    prog->InputsRead = 0;
 159    prog->OutputsWritten = 0;
 160    prog->SystemValuesRead = 0;
 161    visit_list_elements(&v, instructions);
 162 }