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  * Additionally, for fragment shaders, sets the InterpQualifier array.
  30  *
  31  * Mesa programs (gl_program, not gl_shader_program) have a set of
  32  * flags indicating which varyings are read and written.  Computing
  33  * which are actually read from some sort of backend code can be
  34  * tricky when variable array indexing involved.  So this pass
  35  * provides support for setting InputsRead and OutputsWritten right
  36  * from the GLSL IR.
  37  */
  38
  39 #include "main/core.h" /* for struct gl_program */
  40 #include "program/hash_table.h"
  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                                  bool is_fragment_shader)
  49    {
  50       this->prog = prog;
  51       this->is_fragment_shader = is_fragment_shader;
  52       this->ht = hash_table_ctor(0,
  53                                  hash_table_pointer_hash,
  54                                  hash_table_pointer_compare);
  55    }
  56    ~ir_set_program_inouts_visitor()
  57    {
  58       hash_table_dtor(this->ht);
  59    }
  60
  61    virtual ir_visitor_status visit_enter(ir_dereference_array *);
  62    virtual ir_visitor_status visit_enter(ir_function_signature *);
  63    virtual ir_visitor_status visit(ir_dereference_variable *);
  64    virtual ir_visitor_status visit(ir_variable *);
  65
  66    struct gl_program *prog;
  67    struct hash_table *ht;
  68    bool is_fragment_shader;
  69 };
  70
  71 static void
  72 mark(struct gl_program *prog, ir_variable *var, int offset, int len,
  73      bool is_fragment_shader)
  74 {
  75    /* As of GLSL 1.20, varyings can only be floats, floating-point
  76     * vectors or matrices, or arrays of them.  For Mesa programs using
  77     * InputsRead/OutputsWritten, everything but matrices uses one
  78     * slot, while matrices use a slot per column.  Presumably
  79     * something doing a more clever packing would use something other
  80     * than InputsRead/OutputsWritten.
  81     */
  82
  83    for (int i = 0; i < len; i++) {
  84       GLbitfield64 bitfield = BITFIELD64_BIT(var->location + var->index + offset + i);
  85       if (var->mode == ir_var_in) {
  86          prog->InputsRead |= bitfield;
  87          if (is_fragment_shader) {
  88             gl_fragment_program *fprog = (gl_fragment_program *) prog;
  89             fprog->InterpQualifier[var->location + var->index + offset + i] =
  90                (glsl_interp_qualifier) var->interpolation;
  91          }
  92       } else if (var->mode == ir_var_system_value) {
  93          prog->SystemValuesRead |= bitfield;
  94       } else {
  95          prog->OutputsWritten |= bitfield;
  96       }
  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       mark(this->prog, ir->var, 0,
 109            ir->type->length * ir->type->fields.array->matrix_columns,
 110            this->is_fragment_shader);
 111    } else {
 112       mark(this->prog, ir->var, 0, ir->type->matrix_columns,
 113            this->is_fragment_shader);
 114    }
 115
 116    return visit_continue;
 117 }
 118
 119 ir_visitor_status
 120 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
 121 {
 122    ir_dereference_variable *deref_var;
 123    ir_constant *index = ir->array_index->as_constant();
 124    deref_var = ir->array->as_dereference_variable();
 125    ir_variable *var = NULL;
 126
 127    /* Check that we're dereferencing a shader in or out */
 128    if (deref_var)
 129       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
 130
 131    if (index && var) {
 132       int width = 1;
 133
 134       if (deref_var->type->is_array() &&
 135           deref_var->type->fields.array->is_matrix()) {
 136          width = deref_var->type->fields.array->matrix_columns;
 137       }
 138
 139       mark(this->prog, var, index->value.i[0] * width, width,
 140            this->is_fragment_shader);
 141       return visit_continue_with_parent;
 142    }
 143
 144    return visit_continue;
 145 }
 146
 147 ir_visitor_status
 148 ir_set_program_inouts_visitor::visit(ir_variable *ir)
 149 {
 150    if (ir->mode == ir_var_in ||
 151        ir->mode == ir_var_out ||
 152        ir->mode == ir_var_system_value) {
 153       hash_table_insert(this->ht, ir, ir);
 154    }
 155
 156    return visit_continue;
 157 }
 158
 159 ir_visitor_status
 160 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
 161 {
 162    /* We don't want to descend into the function parameters and
 163     * consider them as shader inputs or outputs.
 164     */
 165    visit_list_elements(this, &ir->body);
 166    return visit_continue_with_parent;
 167 }
 168
 169 void
 170 do_set_program_inouts(exec_list *instructions, struct gl_program *prog,
 171                       bool is_fragment_shader)
 172 {
 173    ir_set_program_inouts_visitor v(prog, is_fragment_shader);
 174
 175    prog->InputsRead = 0;
 176    prog->OutputsWritten = 0;
 177    prog->SystemValuesRead = 0;
 178    if (is_fragment_shader) {
 179       memset(((gl_fragment_program *) prog)->InterpQualifier, 0,
 180              sizeof(((gl_fragment_program *) prog)->InterpQualifier));
 181    }
 182    visit_list_elements(&v, instructions);
 183 }