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 extern "C" {
  38 #include "main/core.h" /* for struct gl_program */
  39 #include "program/hash_table.h"
  40 }
  41 #include "ir.h"
  42 #include "ir_visitor.h"
  43 #include "glsl_types.h"
  44
  45 class ir_set_program_inouts_visitor : public ir_hierarchical_visitor {
  46 public:
  47    ir_set_program_inouts_visitor(struct gl_program *prog)
  48    {
  49       this->prog = prog;
  50       this->ht = hash_table_ctor(0,
  51                                  hash_table_pointer_hash,
  52                                  hash_table_pointer_compare);
  53    }
  54    ~ir_set_program_inouts_visitor()
  55    {
  56       hash_table_dtor(this->ht);
  57    }
  58
  59    virtual ir_visitor_status visit_enter(ir_dereference_array *);
  60    virtual ir_visitor_status visit_enter(ir_function_signature *);
  61    virtual ir_visitor_status visit(ir_dereference_variable *);
  62    virtual ir_visitor_status visit(ir_variable *);
  63
  64    struct gl_program *prog;
  65    struct hash_table *ht;
  66 };
  67
  68 static void
  69 mark(struct gl_program *prog, ir_variable *var, int index)
  70 {
  71    /* As of GLSL 1.20, varyings can only be floats, floating-point
  72     * vectors or matrices, or arrays of them.  For Mesa programs using
  73     * InputsRead/OutputsWritten, everything but matrices uses one
  74     * slot, while matrices use a slot per column.  Presumably
  75     * something doing a more clever packing would use something other
  76     * than InputsRead/OutputsWritten.
  77     */
  78    const glsl_type *element_type;
  79    int element_size;
  80
  81    if (var->type->is_array())
  82       element_type = var->type->fields.array;
  83    else
  84       element_type = var->type;
  85
  86    if (element_type->is_matrix())
  87       element_size = element_type->matrix_columns;
  88    else
  89       element_size = 1;
  90
  91    index *= element_size;
  92    for (int i = 0; i < element_size; i++) {
  93       if (var->mode == ir_var_in)
  94          prog->InputsRead |= BITFIELD64_BIT(var->location + index + i);
  95       else
  96          prog->OutputsWritten |= BITFIELD64_BIT(var->location + index + i);
  97    }
  98 }
  99
 100 /* Default handler: Mark all the locations in the variable as used. */
 101 ir_visitor_status
 102 ir_set_program_inouts_visitor::visit(ir_dereference_variable *ir)
 103 {
 104    if (hash_table_find(this->ht, ir->var) == NULL)
 105       return visit_continue;
 106
 107    if (ir->type->is_array()) {
 108       for (unsigned int i = 0; i < ir->type->length; i++) {
 109          mark(this->prog, ir->var, i);
 110       }
 111    } else {
 112       mark(this->prog, ir->var, 0);
 113    }
 114
 115    return visit_continue;
 116 }
 117
 118 ir_visitor_status
 119 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
 120 {
 121    ir_dereference_variable *deref_var;
 122    ir_constant *index = ir->array_index->as_constant();
 123    deref_var = ir->array->as_dereference_variable();
 124    ir_variable *var = NULL;
 125
 126    /* Check that we're dereferencing a shader in or out */
 127    if (deref_var)
 128       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
 129
 130    if (index && var) {
 131       mark(this->prog, var, index->value.i[0]);
 132       return visit_continue_with_parent;
 133    }
 134
 135    return visit_continue;
 136 }
 137
 138 ir_visitor_status
 139 ir_set_program_inouts_visitor::visit(ir_variable *ir)
 140 {
 141    if (ir->mode == ir_var_in ||
 142        ir->mode == ir_var_out) {
 143       hash_table_insert(this->ht, ir, ir);
 144    }
 145
 146    return visit_continue;
 147 }
 148
 149 ir_visitor_status
 150 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
 151 {
 152    /* We don't want to descend into the function parameters and
 153     * consider them as shader inputs or outputs.
 154     */
 155    visit_list_elements(this, &ir->body);
 156    return visit_continue_with_parent;
 157 }
 158
 159 void
 160 do_set_program_inouts(exec_list *instructions, struct gl_program *prog)
 161 {
 162    ir_set_program_inouts_visitor v(prog);
 163
 164    prog->InputsRead = 0;
 165    prog->OutputsWritten = 0;
 166    visit_list_elements(&v, instructions);
 167 }