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, the
  30  * IsCentroid bitfield, and the UsesDFdy flag.
  31  *
  32  * Mesa programs (gl_program, not gl_shader_program) have a set of
  33  * flags indicating which varyings are read and written.  Computing
  34  * which are actually read from some sort of backend code can be
  35  * tricky when variable array indexing involved.  So this pass
  36  * provides support for setting InputsRead and OutputsWritten right
  37  * from the GLSL IR.
  38  */
  39
  40 #include "main/core.h" /* for struct gl_program */
  41 #include "program/hash_table.h"
  42 #include "ir.h"
  43 #include "ir_visitor.h"
  44 #include "glsl_types.h"
  45
  46 class ir_set_program_inouts_visitor : public ir_hierarchical_visitor {
  47 public:
  48    ir_set_program_inouts_visitor(struct gl_program *prog,
  49                                  bool is_fragment_shader)
  50    {
  51       this->prog = prog;
  52       this->is_fragment_shader = is_fragment_shader;
  53       this->ht = hash_table_ctor(0,
  54                                  hash_table_pointer_hash,
  55                                  hash_table_pointer_compare);
  56    }
  57    ~ir_set_program_inouts_visitor()
  58    {
  59       hash_table_dtor(this->ht);
  60    }
  61
  62    virtual ir_visitor_status visit_enter(ir_dereference_array *);
  63    virtual ir_visitor_status visit_enter(ir_function_signature *);
  64    virtual ir_visitor_status visit_enter(ir_expression *);
  65    virtual ir_visitor_status visit_enter(ir_discard *);
  66    virtual ir_visitor_status visit(ir_dereference_variable *);
  67    virtual ir_visitor_status visit(ir_variable *);
  68
  69    struct gl_program *prog;
  70    struct hash_table *ht;
  71    bool is_fragment_shader;
  72 };
  73
  74 static void
  75 mark(struct gl_program *prog, ir_variable *var, int offset, int len,
  76      bool is_fragment_shader)
  77 {
  78    /* As of GLSL 1.20, varyings can only be floats, floating-point
  79     * vectors or matrices, or arrays of them.  For Mesa programs using
  80     * InputsRead/OutputsWritten, everything but matrices uses one
  81     * slot, while matrices use a slot per column.  Presumably
  82     * something doing a more clever packing would use something other
  83     * than InputsRead/OutputsWritten.
  84     */
  85
  86    for (int i = 0; i < len; i++) {
  87       GLbitfield64 bitfield = BITFIELD64_BIT(var->location + var->index + offset + i);
  88       if (var->mode == ir_var_in) {
  89          prog->InputsRead |= bitfield;
  90          if (is_fragment_shader) {
  91             gl_fragment_program *fprog = (gl_fragment_program *) prog;
  92             fprog->InterpQualifier[var->location + var->index + offset + i] =
  93                (glsl_interp_qualifier) var->interpolation;
  94             if (var->centroid)
  95                fprog->IsCentroid |= bitfield;
  96          }
  97       } else if (var->mode == ir_var_system_value) {
  98          prog->SystemValuesRead |= bitfield;
  99       } else {
 100          prog->OutputsWritten |= bitfield;
 101       }
 102    }
 103 }
 104
 105 /* Default handler: Mark all the locations in the variable as used. */
 106 ir_visitor_status
 107 ir_set_program_inouts_visitor::visit(ir_dereference_variable *ir)
 108 {
 109    if (hash_table_find(this->ht, ir->var) == NULL)
 110       return visit_continue;
 111
 112    if (ir->type->is_array()) {
 113       mark(this->prog, ir->var, 0,
 114            ir->type->length * ir->type->fields.array->matrix_columns,
 115            this->is_fragment_shader);
 116    } else {
 117       mark(this->prog, ir->var, 0, ir->type->matrix_columns,
 118            this->is_fragment_shader);
 119    }
 120
 121    return visit_continue;
 122 }
 123
 124 ir_visitor_status
 125 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
 126 {
 127    ir_dereference_variable *deref_var;
 128    ir_constant *index = ir->array_index->as_constant();
 129    deref_var = ir->array->as_dereference_variable();
 130    ir_variable *var = NULL;
 131
 132    /* Check that we're dereferencing a shader in or out */
 133    if (deref_var)
 134       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
 135
 136    if (index && var) {
 137       int width = 1;
 138
 139       if (deref_var->type->is_array() &&
 140           deref_var->type->fields.array->is_matrix()) {
 141          width = deref_var->type->fields.array->matrix_columns;
 142       }
 143
 144       mark(this->prog, var, index->value.i[0] * width, width,
 145            this->is_fragment_shader);
 146       return visit_continue_with_parent;
 147    }
 148
 149    return visit_continue;
 150 }
 151
 152 ir_visitor_status
 153 ir_set_program_inouts_visitor::visit(ir_variable *ir)
 154 {
 155    if (ir->mode == ir_var_in ||
 156        ir->mode == ir_var_out ||
 157        ir->mode == ir_var_system_value) {
 158       hash_table_insert(this->ht, ir, ir);
 159    }
 160
 161    return visit_continue;
 162 }
 163
 164 ir_visitor_status
 165 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
 166 {
 167    /* We don't want to descend into the function parameters and
 168     * consider them as shader inputs or outputs.
 169     */
 170    visit_list_elements(this, &ir->body);
 171    return visit_continue_with_parent;
 172 }
 173
 174 ir_visitor_status
 175 ir_set_program_inouts_visitor::visit_enter(ir_expression *ir)
 176 {
 177    if (is_fragment_shader && ir->operation == ir_unop_dFdy) {
 178       gl_fragment_program *fprog = (gl_fragment_program *) prog;
 179       fprog->UsesDFdy = true;
 180    }
 181    return visit_continue;
 182 }
 183
 184 ir_visitor_status
 185 ir_set_program_inouts_visitor::visit_enter(ir_discard *)
 186 {
 187    /* discards are only allowed in fragment shaders. */
 188    assert(is_fragment_shader);
 189
 190    gl_fragment_program *fprog = (gl_fragment_program *) prog;
 191    fprog->UsesKill = true;
 192
 193    return visit_continue;
 194 }
 195
 196 void
 197 do_set_program_inouts(exec_list *instructions, struct gl_program *prog,
 198                       bool is_fragment_shader)
 199 {
 200    ir_set_program_inouts_visitor v(prog, is_fragment_shader);
 201
 202    prog->InputsRead = 0;
 203    prog->OutputsWritten = 0;
 204    prog->SystemValuesRead = 0;
 205    if (is_fragment_shader) {
 206       gl_fragment_program *fprog = (gl_fragment_program *) prog;
 207       memset(fprog->InterpQualifier, 0, sizeof(fprog->InterpQualifier));
 208       fprog->IsCentroid = 0;
 209       fprog->UsesDFdy = false;
 210       fprog->UsesKill = false;
 211    }
 212    visit_list_elements(&v, instructions);
 213 }