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 and
  30  * IsCentroid bitfield.
  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(ir_dereference_variable *);
  65    virtual ir_visitor_status visit(ir_variable *);
  66
  67    struct gl_program *prog;
  68    struct hash_table *ht;
  69    bool is_fragment_shader;
  70 };
  71
  72 static void
  73 mark(struct gl_program *prog, ir_variable *var, int offset, int len,
  74      bool is_fragment_shader)
  75 {
  76    /* As of GLSL 1.20, varyings can only be floats, floating-point
  77     * vectors or matrices, or arrays of them.  For Mesa programs using
  78     * InputsRead/OutputsWritten, everything but matrices uses one
  79     * slot, while matrices use a slot per column.  Presumably
  80     * something doing a more clever packing would use something other
  81     * than InputsRead/OutputsWritten.
  82     */
  83
  84    for (int i = 0; i < len; i++) {
  85       GLbitfield64 bitfield = BITFIELD64_BIT(var->location + var->index + offset + i);
  86       if (var->mode == ir_var_in) {
  87          prog->InputsRead |= bitfield;
  88          if (is_fragment_shader) {
  89             gl_fragment_program *fprog = (gl_fragment_program *) prog;
  90             fprog->InterpQualifier[var->location + var->index + offset + i] =
  91                (glsl_interp_qualifier) var->interpolation;
  92             if (var->centroid)
  93                fprog->IsCentroid |= bitfield;
  94          }
  95       } else if (var->mode == ir_var_system_value) {
  96          prog->SystemValuesRead |= bitfield;
  97       } else {
  98          prog->OutputsWritten |= bitfield;
  99       }
 100    }
 101 }
 102
 103 /* Default handler: Mark all the locations in the variable as used. */
 104 ir_visitor_status
 105 ir_set_program_inouts_visitor::visit(ir_dereference_variable *ir)
 106 {
 107    if (hash_table_find(this->ht, ir->var) == NULL)
 108       return visit_continue;
 109
 110    if (ir->type->is_array()) {
 111       mark(this->prog, ir->var, 0,
 112            ir->type->length * ir->type->fields.array->matrix_columns,
 113            this->is_fragment_shader);
 114    } else {
 115       mark(this->prog, ir->var, 0, ir->type->matrix_columns,
 116            this->is_fragment_shader);
 117    }
 118
 119    return visit_continue;
 120 }
 121
 122 ir_visitor_status
 123 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
 124 {
 125    ir_dereference_variable *deref_var;
 126    ir_constant *index = ir->array_index->as_constant();
 127    deref_var = ir->array->as_dereference_variable();
 128    ir_variable *var = NULL;
 129
 130    /* Check that we're dereferencing a shader in or out */
 131    if (deref_var)
 132       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
 133
 134    if (index && var) {
 135       int width = 1;
 136
 137       if (deref_var->type->is_array() &&
 138           deref_var->type->fields.array->is_matrix()) {
 139          width = deref_var->type->fields.array->matrix_columns;
 140       }
 141
 142       mark(this->prog, var, index->value.i[0] * width, width,
 143            this->is_fragment_shader);
 144       return visit_continue_with_parent;
 145    }
 146
 147    return visit_continue;
 148 }
 149
 150 ir_visitor_status
 151 ir_set_program_inouts_visitor::visit(ir_variable *ir)
 152 {
 153    if (ir->mode == ir_var_in ||
 154        ir->mode == ir_var_out ||
 155        ir->mode == ir_var_system_value) {
 156       hash_table_insert(this->ht, ir, ir);
 157    }
 158
 159    return visit_continue;
 160 }
 161
 162 ir_visitor_status
 163 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
 164 {
 165    /* We don't want to descend into the function parameters and
 166     * consider them as shader inputs or outputs.
 167     */
 168    visit_list_elements(this, &ir->body);
 169    return visit_continue_with_parent;
 170 }
 171
 172 void
 173 do_set_program_inouts(exec_list *instructions, struct gl_program *prog,
 174                       bool is_fragment_shader)
 175 {
 176    ir_set_program_inouts_visitor v(prog, is_fragment_shader);
 177
 178    prog->InputsRead = 0;
 179    prog->OutputsWritten = 0;
 180    prog->SystemValuesRead = 0;
 181    if (is_fragment_shader) {
 182       memset(((gl_fragment_program *) prog)->InterpQualifier, 0,
 183              sizeof(((gl_fragment_program *) prog)->InterpQualifier));
 184       ((gl_fragment_program *) prog)->IsCentroid = 0;
 185    }
 186    visit_list_elements(&v, instructions);
 187 }