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/*
* Copyright ©2019 Collabora Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file lower_xfb_varying.cpp
*
*/
#include "ir.h"
#include "main/mtypes.h"
#include "glsl_symbol_table.h"
#include "util/strndup.h"
namespace {
/**
* Visitor that splices varying packing code before every return.
*/
class lower_xfb_var_splicer : public ir_hierarchical_visitor
{
public:
explicit lower_xfb_var_splicer(void *mem_ctx,
const exec_list *instructions);
virtual ir_visitor_status visit_leave(ir_return *ret);
virtual ir_visitor_status visit_leave(ir_function_signature *sig);
private:
/**
* Memory context used to allocate new instructions for the shader.
*/
void * const mem_ctx;
/**
* Instructions that should be spliced into place before each return.
*/
const exec_list *instructions;
};
} /* anonymous namespace */
lower_xfb_var_splicer::lower_xfb_var_splicer(void *mem_ctx, const exec_list *instructions)
: mem_ctx(mem_ctx), instructions(instructions)
{
}
ir_visitor_status
lower_xfb_var_splicer::visit_leave(ir_return *ret)
{
foreach_in_list(ir_instruction, ir, this->instructions) {
ret->insert_before(ir->clone(this->mem_ctx, NULL));
}
return visit_continue;
}
/** Insert a copy-back assignment at the end of the main() function */
ir_visitor_status
lower_xfb_var_splicer::visit_leave(ir_function_signature *sig)
{
if (strcmp(sig->function_name(), "main") != 0)
return visit_continue;
if (((ir_instruction*)sig->body.get_tail())->ir_type == ir_type_return)
return visit_continue;
foreach_in_list(ir_instruction, ir, this->instructions) {
sig->body.push_tail(ir->clone(this->mem_ctx, NULL));
}
return visit_continue;
}
static char*
get_field_name(const char *name)
{
const char *first_dot = strchr(name, '.');
const char *first_square_bracket = strchr(name, '[');
int name_size = 0;
if (!first_square_bracket && !first_dot)
name_size = strlen(name);
else if ((!first_square_bracket ||
(first_dot && first_dot < first_square_bracket)))
name_size = first_dot - name;
else
name_size = first_square_bracket - name;
return strndup(name, name_size);
}
/* Generate a new name given the old xfb declaration string by replacing dots
* with '_', brackets with '@' and appending "-xfb" */
static char *
generate_new_name(void *mem_ctx, const char *name)
{
char *new_name;
unsigned i = 0;
new_name = ralloc_strdup(mem_ctx, name);
while (new_name[i]) {
if (new_name[i] == '.') {
new_name[i] = '_';
} else if (new_name[i] == '[' || new_name[i] == ']') {
new_name[i] = '@';
}
i++;
}
if (!ralloc_strcat(&new_name, "-xfb")) {
ralloc_free(new_name);
return NULL;
}
return new_name;
}
/* Get the dereference for the given variable name. The method is called
* recursively to parse array indices and struct members. */
static bool
get_deref(void *ctx,
const char *name,
struct gl_linked_shader *shader,
ir_dereference **deref,
const glsl_type **type)
{
if (name[0] == '\0') {
/* End */
return (*deref != NULL);
} else if (name[0] == '[') {
/* Array index */
char *endptr = NULL;
unsigned index;
index = strtol(name + 1, &endptr, 10);
assert(*type != NULL && (*type)->is_array() && endptr[0] == ']');
*deref = new(ctx) ir_dereference_array(*deref, new(ctx) ir_constant(index));
*type = (*type)->without_array();
return get_deref(ctx, endptr + 1, shader, deref, type);
} else if (name[0] == '.') {
/* Struct member */
char *field = get_field_name(name + 1);
assert(*type != NULL && (*type)->is_struct() && field != NULL);
*deref = new(ctx) ir_dereference_record(*deref, field);
*type = (*type)->field_type(field);
assert(*type != glsl_type::error_type);
name += 1 + strlen(field);
free(field);
return get_deref(ctx, name, shader, deref, type);
} else {
/* Top level variable */
char *field = get_field_name(name);
ir_variable *toplevel_var;
toplevel_var = shader->symbols->get_variable(field);
name += strlen(field);
free(field);
if (toplevel_var == NULL) {
return false;
}
*deref = new (ctx) ir_dereference_variable(toplevel_var);
*type = toplevel_var->type;
return get_deref(ctx, name, shader, deref, type);
}
}
ir_variable *
lower_xfb_varying(void *mem_ctx,
struct gl_linked_shader *shader,
const char *old_var_name)
{
exec_list new_instructions;
char *new_var_name;
ir_dereference *deref = NULL;
const glsl_type *type = NULL;
if (!get_deref(mem_ctx, old_var_name, shader, &deref, &type)) {
if (deref) {
delete deref;
}
return NULL;
}
new_var_name = generate_new_name(mem_ctx, old_var_name);
ir_variable *new_variable
= new(mem_ctx) ir_variable(type, new_var_name, ir_var_shader_out);
new_variable->data.assigned = true;
new_variable->data.used = true;
shader->ir->push_head(new_variable);
ralloc_free(new_var_name);
ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(new_variable);
ir_assignment *new_assignment = new(mem_ctx) ir_assignment(lhs, deref);
new_instructions.push_tail(new_assignment);
lower_xfb_var_splicer splicer(mem_ctx, &new_instructions);
visit_list_elements(&splicer, shader->ir);
return new_variable;
}