Home | History | Annotate | Download | only in glsl
      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 opt_structure_splitting.cpp
     26  *
     27  * If a structure is only ever referenced by its components, then
     28  * split those components out to individual variables so they can be
     29  * handled normally by other optimization passes.
     30  *
     31  * This skips structures like uniforms, which need to be accessible as
     32  * structures for their access by the GL.
     33  */
     34 
     35 #include "ir.h"
     36 #include "ir_visitor.h"
     37 #include "ir_rvalue_visitor.h"
     38 #include "compiler/glsl_types.h"
     39 
     40 namespace {
     41 
     42 static bool debug = false;
     43 
     44 class variable_entry : public exec_node
     45 {
     46 public:
     47    variable_entry(ir_variable *var)
     48    {
     49       this->var = var;
     50       this->whole_structure_access = 0;
     51       this->declaration = false;
     52       this->components = NULL;
     53       this->mem_ctx = NULL;
     54    }
     55 
     56    ir_variable *var; /* The key: the variable's pointer. */
     57 
     58    /** Number of times the variable is referenced, including assignments. */
     59    unsigned whole_structure_access;
     60 
     61    /* If the variable had a decl we can work with in the instruction
     62     * stream.  We can't do splitting on function arguments, which
     63     * don't get this variable set.
     64     */
     65    bool declaration;
     66 
     67    ir_variable **components;
     68 
     69    /** ralloc_parent(this->var) -- the shader's ralloc context. */
     70    void *mem_ctx;
     71 };
     72 
     73 
     74 class ir_structure_reference_visitor : public ir_hierarchical_visitor {
     75 public:
     76    ir_structure_reference_visitor(void)
     77    {
     78       this->mem_ctx = ralloc_context(NULL);
     79       this->variable_list.make_empty();
     80    }
     81 
     82    ~ir_structure_reference_visitor(void)
     83    {
     84       ralloc_free(mem_ctx);
     85    }
     86 
     87    virtual ir_visitor_status visit(ir_variable *);
     88    virtual ir_visitor_status visit(ir_dereference_variable *);
     89    virtual ir_visitor_status visit_enter(ir_dereference_record *);
     90    virtual ir_visitor_status visit_enter(ir_assignment *);
     91    virtual ir_visitor_status visit_enter(ir_function_signature *);
     92 
     93    variable_entry *get_variable_entry(ir_variable *var);
     94 
     95    /* List of variable_entry */
     96    exec_list variable_list;
     97 
     98    void *mem_ctx;
     99 };
    100 
    101 variable_entry *
    102 ir_structure_reference_visitor::get_variable_entry(ir_variable *var)
    103 {
    104    assert(var);
    105 
    106    if (!var->type->is_record() ||
    107        var->data.mode == ir_var_uniform || var->data.mode == ir_var_shader_storage ||
    108        var->data.mode == ir_var_shader_in || var->data.mode == ir_var_shader_out)
    109       return NULL;
    110 
    111    foreach_in_list(variable_entry, entry, &this->variable_list) {
    112       if (entry->var == var)
    113 	 return entry;
    114    }
    115 
    116    variable_entry *entry = new(mem_ctx) variable_entry(var);
    117    this->variable_list.push_tail(entry);
    118    return entry;
    119 }
    120 
    121 
    122 ir_visitor_status
    123 ir_structure_reference_visitor::visit(ir_variable *ir)
    124 {
    125    variable_entry *entry = this->get_variable_entry(ir);
    126 
    127    if (entry)
    128       entry->declaration = true;
    129 
    130    return visit_continue;
    131 }
    132 
    133 ir_visitor_status
    134 ir_structure_reference_visitor::visit(ir_dereference_variable *ir)
    135 {
    136    ir_variable *const var = ir->variable_referenced();
    137    variable_entry *entry = this->get_variable_entry(var);
    138 
    139    if (entry)
    140       entry->whole_structure_access++;
    141 
    142    return visit_continue;
    143 }
    144 
    145 ir_visitor_status
    146 ir_structure_reference_visitor::visit_enter(ir_dereference_record *ir)
    147 {
    148    (void) ir;
    149    /* Don't descend into the ir_dereference_variable below. */
    150    return visit_continue_with_parent;
    151 }
    152 
    153 ir_visitor_status
    154 ir_structure_reference_visitor::visit_enter(ir_assignment *ir)
    155 {
    156    /* If there are no structure references yet, no need to bother with
    157     * processing the expression tree.
    158     */
    159    if (this->variable_list.is_empty())
    160       return visit_continue_with_parent;
    161 
    162    if (ir->lhs->as_dereference_variable() &&
    163        ir->rhs->as_dereference_variable() &&
    164        !ir->condition) {
    165       /* We'll split copies of a structure to copies of components, so don't
    166        * descend to the ir_dereference_variables.
    167        */
    168       return visit_continue_with_parent;
    169    }
    170    return visit_continue;
    171 }
    172 
    173 ir_visitor_status
    174 ir_structure_reference_visitor::visit_enter(ir_function_signature *ir)
    175 {
    176    /* We don't have logic for structure-splitting function arguments,
    177     * so just look at the body instructions and not the parameter
    178     * declarations.
    179     */
    180    visit_list_elements(this, &ir->body);
    181    return visit_continue_with_parent;
    182 }
    183 
    184 class ir_structure_splitting_visitor : public ir_rvalue_visitor {
    185 public:
    186    ir_structure_splitting_visitor(exec_list *vars)
    187    {
    188       this->variable_list = vars;
    189    }
    190 
    191    virtual ~ir_structure_splitting_visitor()
    192    {
    193    }
    194 
    195    virtual ir_visitor_status visit_leave(ir_assignment *);
    196 
    197    void split_deref(ir_dereference **deref);
    198    void handle_rvalue(ir_rvalue **rvalue);
    199    variable_entry *get_splitting_entry(ir_variable *var);
    200 
    201    exec_list *variable_list;
    202 };
    203 
    204 variable_entry *
    205 ir_structure_splitting_visitor::get_splitting_entry(ir_variable *var)
    206 {
    207    assert(var);
    208 
    209    if (!var->type->is_record())
    210       return NULL;
    211 
    212    foreach_in_list(variable_entry, entry, this->variable_list) {
    213       if (entry->var == var) {
    214 	 return entry;
    215       }
    216    }
    217 
    218    return NULL;
    219 }
    220 
    221 void
    222 ir_structure_splitting_visitor::split_deref(ir_dereference **deref)
    223 {
    224    if ((*deref)->ir_type != ir_type_dereference_record)
    225       return;
    226 
    227    ir_dereference_record *deref_record = (ir_dereference_record *)*deref;
    228    ir_dereference_variable *deref_var = deref_record->record->as_dereference_variable();
    229    if (!deref_var)
    230       return;
    231 
    232    variable_entry *entry = get_splitting_entry(deref_var->var);
    233    if (!entry)
    234       return;
    235 
    236    int i = deref_record->field_idx;
    237    assert(i >= 0);
    238    assert((unsigned) i < entry->var->type->length);
    239 
    240    *deref = new(entry->mem_ctx) ir_dereference_variable(entry->components[i]);
    241 }
    242 
    243 void
    244 ir_structure_splitting_visitor::handle_rvalue(ir_rvalue **rvalue)
    245 {
    246    if (!*rvalue)
    247       return;
    248 
    249    ir_dereference *deref = (*rvalue)->as_dereference();
    250 
    251    if (!deref)
    252       return;
    253 
    254    split_deref(&deref);
    255    *rvalue = deref;
    256 }
    257 
    258 ir_visitor_status
    259 ir_structure_splitting_visitor::visit_leave(ir_assignment *ir)
    260 {
    261    ir_dereference_variable *lhs_deref = ir->lhs->as_dereference_variable();
    262    ir_dereference_variable *rhs_deref = ir->rhs->as_dereference_variable();
    263    variable_entry *lhs_entry = lhs_deref ? get_splitting_entry(lhs_deref->var) : NULL;
    264    variable_entry *rhs_entry = rhs_deref ? get_splitting_entry(rhs_deref->var) : NULL;
    265    const glsl_type *type = ir->rhs->type;
    266 
    267    if ((lhs_entry || rhs_entry) && !ir->condition) {
    268       for (unsigned int i = 0; i < type->length; i++) {
    269 	 ir_dereference *new_lhs, *new_rhs;
    270 	 void *mem_ctx = lhs_entry ? lhs_entry->mem_ctx : rhs_entry->mem_ctx;
    271 
    272 	 if (lhs_entry) {
    273 	    new_lhs = new(mem_ctx) ir_dereference_variable(lhs_entry->components[i]);
    274 	 } else {
    275 	    new_lhs = new(mem_ctx)
    276 	       ir_dereference_record(ir->lhs->clone(mem_ctx, NULL),
    277 				     type->fields.structure[i].name);
    278 	 }
    279 
    280 	 if (rhs_entry) {
    281 	    new_rhs = new(mem_ctx) ir_dereference_variable(rhs_entry->components[i]);
    282 	 } else {
    283 	    new_rhs = new(mem_ctx)
    284 	       ir_dereference_record(ir->rhs->clone(mem_ctx, NULL),
    285 				     type->fields.structure[i].name);
    286 	 }
    287 
    288          ir->insert_before(new(mem_ctx) ir_assignment(new_lhs, new_rhs));
    289       }
    290       ir->remove();
    291    } else {
    292       handle_rvalue(&ir->rhs);
    293       split_deref(&ir->lhs);
    294    }
    295 
    296    handle_rvalue(&ir->condition);
    297 
    298    return visit_continue;
    299 }
    300 
    301 } /* unnamed namespace */
    302 
    303 bool
    304 do_structure_splitting(exec_list *instructions)
    305 {
    306    ir_structure_reference_visitor refs;
    307 
    308    visit_list_elements(&refs, instructions);
    309 
    310    /* Trim out variables we can't split. */
    311    foreach_in_list_safe(variable_entry, entry, &refs.variable_list) {
    312       if (debug) {
    313          printf("structure %s@%p: decl %d, whole_access %d\n",
    314                 entry->var->name, (void *) entry->var, entry->declaration,
    315                 entry->whole_structure_access);
    316       }
    317 
    318       if (!entry->declaration || entry->whole_structure_access) {
    319          entry->remove();
    320       }
    321    }
    322 
    323    if (refs.variable_list.is_empty())
    324       return false;
    325 
    326    void *mem_ctx = ralloc_context(NULL);
    327 
    328    /* Replace the decls of the structures to be split with their split
    329     * components.
    330     */
    331    foreach_in_list_safe(variable_entry, entry, &refs.variable_list) {
    332       const struct glsl_type *type = entry->var->type;
    333 
    334       entry->mem_ctx = ralloc_parent(entry->var);
    335 
    336       entry->components = ralloc_array(mem_ctx, ir_variable *, type->length);
    337 
    338       for (unsigned int i = 0; i < entry->var->type->length; i++) {
    339          const char *name = ralloc_asprintf(mem_ctx, "%s_%s", entry->var->name,
    340                                             type->fields.structure[i].name);
    341          ir_variable *new_var =
    342             new(entry->mem_ctx) ir_variable(type->fields.structure[i].type,
    343                                             name,
    344                                             (ir_variable_mode) entry->var->data.mode);
    345 
    346          if (type->fields.structure[i].type->without_array()->is_image()) {
    347             /* Do not lose memory/format qualifiers for images declared inside
    348              * structures as allowed by ARB_bindless_texture.
    349              */
    350             new_var->data.memory_read_only =
    351                type->fields.structure[i].memory_read_only;
    352             new_var->data.memory_write_only =
    353                type->fields.structure[i].memory_write_only;
    354             new_var->data.memory_coherent =
    355                type->fields.structure[i].memory_coherent;
    356             new_var->data.memory_volatile =
    357                type->fields.structure[i].memory_volatile;
    358             new_var->data.memory_restrict =
    359                type->fields.structure[i].memory_restrict;
    360             new_var->data.image_format =
    361                type->fields.structure[i].image_format;
    362          }
    363 
    364          entry->components[i] = new_var;
    365          entry->var->insert_before(entry->components[i]);
    366       }
    367 
    368       entry->var->remove();
    369    }
    370 
    371    ir_structure_splitting_visitor split(&refs.variable_list);
    372    visit_list_elements(&split, instructions);
    373 
    374    ralloc_free(mem_ctx);
    375 
    376    return true;
    377 }
    378