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      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 offset, int len)
     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 
     79    for (int i = 0; i < len; i++) {
     80       if (var->mode == ir_var_in)
     81 	 prog->InputsRead |= BITFIELD64_BIT(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       for (unsigned int i = 0; i < ir->type->length; i++) {
     96 	 mark(this->prog, ir->var, i,
     97 	      ir->type->length * ir->type->fields.array->matrix_columns);
     98       }
     99    } else {
    100       mark(this->prog, ir->var, 0, ir->type->matrix_columns);
    101    }
    102 
    103    return visit_continue;
    104 }
    105 
    106 ir_visitor_status
    107 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
    108 {
    109    ir_dereference_variable *deref_var;
    110    ir_constant *index = ir->array_index->as_constant();
    111    deref_var = ir->array->as_dereference_variable();
    112    ir_variable *var = NULL;
    113 
    114    /* Check that we're dereferencing a shader in or out */
    115    if (deref_var)
    116       var = (ir_variable *)hash_table_find(this->ht, deref_var->var);
    117 
    118    if (index && var) {
    119       int width = 1;
    120 
    121       if (deref_var->type->is_array() &&
    122 	  deref_var->type->fields.array->is_matrix()) {
    123 	 width = deref_var->type->fields.array->matrix_columns;
    124       }
    125 
    126       mark(this->prog, var, index->value.i[0] * width, width);
    127       return visit_continue_with_parent;
    128    }
    129 
    130    return visit_continue;
    131 }
    132 
    133 ir_visitor_status
    134 ir_set_program_inouts_visitor::visit(ir_variable *ir)
    135 {
    136    if (ir->mode == ir_var_in ||
    137        ir->mode == ir_var_out) {
    138       hash_table_insert(this->ht, ir, ir);
    139    }
    140 
    141    return visit_continue;
    142 }
    143 
    144 ir_visitor_status
    145 ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
    146 {
    147    /* We don't want to descend into the function parameters and
    148     * consider them as shader inputs or outputs.
    149     */
    150    visit_list_elements(this, &ir->body);
    151    return visit_continue_with_parent;
    152 }
    153 
    154 void
    155 do_set_program_inouts(exec_list *instructions, struct gl_program *prog)
    156 {
    157    ir_set_program_inouts_visitor v(prog);
    158 
    159    prog->InputsRead = 0;
    160    prog->OutputsWritten = 0;
    161    visit_list_elements(&v, instructions);
    162 }
    163