/*
* Copyright © 2010 Intel Corporation
*
* 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.
*/
#include "main/core.h"
#include "glsl_symbol_table.h"
#include "glsl_parser_extras.h"
#include "ir.h"
#include "program.h"
#include "program/hash_table.h"
#include "linker.h"
static ir_function_signature *
find_matching_signature(const char *name, const exec_list *actual_parameters,
gl_shader **shader_list, unsigned num_shaders,
bool use_builtin);
class call_link_visitor : public ir_hierarchical_visitor {
public:
call_link_visitor(gl_shader_program *prog, gl_shader *linked,
gl_shader **shader_list, unsigned num_shaders)
{
this->prog = prog;
this->shader_list = shader_list;
this->num_shaders = num_shaders;
this->success = true;
this->linked = linked;
this->locals = hash_table_ctor(0, hash_table_pointer_hash,
hash_table_pointer_compare);
}
~call_link_visitor()
{
hash_table_dtor(this->locals);
}
virtual ir_visitor_status visit(ir_variable *ir)
{
hash_table_insert(locals, ir, ir);
return visit_continue;
}
virtual ir_visitor_status visit_enter(ir_call *ir)
{
/* If ir is an ir_call from a function that was imported from another
* shader callee will point to an ir_function_signature in the original
* shader. In this case the function signature MUST NOT BE MODIFIED.
* Doing so will modify the original shader. This may prevent that
* shader from being linkable in other programs.
*/
const ir_function_signature *const callee = ir->callee;
assert(callee != NULL);
const char *const name = callee->function_name();
/* Determine if the requested function signature already exists in the
* final linked shader. If it does, use it as the target of the call.
*/
ir_function_signature *sig =
find_matching_signature(name, &callee->parameters, &linked, 1,
ir->use_builtin);
if (sig != NULL) {
ir->callee = sig;
return visit_continue;
}
/* Try to find the signature in one of the other shaders that is being
* linked. If it's not found there, return an error.
*/
sig = find_matching_signature(name, &ir->actual_parameters, shader_list,
num_shaders, ir->use_builtin);
if (sig == NULL) {
/* FINISHME: Log the full signature of unresolved function.
*/
linker_error(this->prog, "unresolved reference to function `%s'\n",
name);
this->success = false;
return visit_stop;
}
/* Find the prototype information in the linked shader. Generate any
* details that may be missing.
*/
ir_function *f = linked->symbols->get_function(name);
if (f == NULL) {
f = new(linked) ir_function(name);
/* Add the new function to the linked IR. Put it at the end
* so that it comes after any global variable declarations
* that it refers to.
*/
linked->symbols->add_function(f);
linked->ir->push_tail(f);
}
ir_function_signature *linked_sig =
f->exact_matching_signature(&callee->parameters);
if ((linked_sig == NULL)
|| ((linked_sig != NULL)
&& (linked_sig->is_builtin != ir->use_builtin))) {
linked_sig = new(linked) ir_function_signature(callee->return_type);
f->add_signature(linked_sig);
}
/* At this point linked_sig and called may be the same. If ir is an
* ir_call from linked then linked_sig and callee will be
* ir_function_signatures that have no definitions (is_defined is false).
*/
assert(!linked_sig->is_defined);
assert(linked_sig->body.is_empty());
/* Create an in-place clone of the function definition. This multistep
* process introduces some complexity here, but it has some advantages.
* The parameter list and the and function body are cloned separately.
* The clone of the parameter list is used to prime the hashtable used
* to replace variable references in the cloned body.
*
* The big advantage is that the ir_function_signature does not change.
* This means that we don't have to process the rest of the IR tree to
* patch ir_call nodes. In addition, there is no way to remove or
* replace signature stored in a function. One could easily be added,
* but this avoids the need.
*/
struct hash_table *ht = hash_table_ctor(0, hash_table_pointer_hash,
hash_table_pointer_compare);
exec_list formal_parameters;
foreach_list_const(node, &sig->parameters) {
const ir_instruction *const original = (ir_instruction *) node;
assert(const_cast<ir_instruction *>(original)->as_variable());
ir_instruction *copy = original->clone(linked, ht);
formal_parameters.push_tail(copy);
}
linked_sig->replace_parameters(&formal_parameters);
foreach_list_const(node, &sig->body) {
const ir_instruction *const original = (ir_instruction *) node;
ir_instruction *copy = original->clone(linked, ht);
linked_sig->body.push_tail(copy);
}
linked_sig->is_defined = true;
hash_table_dtor(ht);
/* Patch references inside the function to things outside the function
* (i.e., function calls and global variables).
*/
linked_sig->accept(this);
ir->callee = linked_sig;
return visit_continue;
}
virtual ir_visitor_status visit_leave(ir_call *ir)
{
/* Traverse list of function parameters, and for array parameters
* propagate max_array_access. Otherwise arrays that are only referenced
* from inside functions via function parameters will be incorrectly
* optimized. This will lead to incorrect code being generated (or worse).
* Do it when leaving the node so the children would propagate their
* array accesses first.
*/
const exec_node *formal_param_node = ir->callee->parameters.get_head();
if (formal_param_node) {
const exec_node *actual_param_node = ir->actual_parameters.get_head();
while (!actual_param_node->is_tail_sentinel()) {
ir_variable *formal_param = (ir_variable *) formal_param_node;
ir_rvalue *actual_param = (ir_rvalue *) actual_param_node;
formal_param_node = formal_param_node->get_next();
actual_param_node = actual_param_node->get_next();
if (formal_param->type->is_array()) {
ir_dereference_variable *deref = actual_param->as_dereference_variable();
if (deref && deref->var && deref->var->type->is_array()) {
deref->var->max_array_access =
MAX2(formal_param->max_array_access, deref->var->max_array_access);
}
}
}
}
return visit_continue;
}
virtual ir_visitor_status visit(ir_dereference_variable *ir)
{
if (hash_table_find(locals, ir->var) == NULL) {
/* The non-function variable must be a global, so try to find the
* variable in the shader's symbol table. If the variable is not
* found, then it's a global that *MUST* be defined in the original
* shader.
*/
ir_variable *var = linked->symbols->get_variable(ir->var->name);
if (var == NULL) {
/* Clone the ir_variable that the dereference already has and add
* it to the linked shader.
*/
var = ir->var->clone(linked, NULL);
linked->symbols->add_variable(var);
linked->ir->push_head(var);
} else if (var->type->is_array()) {
/* It is possible to have a global array declared in multiple
* shaders without a size. The array is implicitly sized by the
* maximal access to it in *any* shader. Because of this, we
* need to track the maximal access to the array as linking pulls
* more functions in that access the array.
*/
var->max_array_access =
MAX2(var->max_array_access, ir->var->max_array_access);
if (var->type->length == 0 && ir->var->type->length != 0)
var->type = ir->var->type;
}
ir->var = var;
}
return visit_continue;
}
/** Was function linking successful? */
bool success;
private:
/**
* Shader program being linked
*
* This is only used for logging error messages.
*/
gl_shader_program *prog;
/** List of shaders available for linking. */
gl_shader **shader_list;
/** Number of shaders available for linking. */
unsigned num_shaders;
/**
* Final linked shader
*
* This is used two ways. It is used to find global variables in the
* linked shader that are accessed by the function. It is also used to add
* global variables from the shader where the function originated.
*/
gl_shader *linked;
/**
* Table of variables local to the function.
*/
hash_table *locals;
};
/**
* Searches a list of shaders for a particular function definition
*/
ir_function_signature *
find_matching_signature(const char *name, const exec_list *actual_parameters,
gl_shader **shader_list, unsigned num_shaders,
bool use_builtin)
{
for (unsigned i = 0; i < num_shaders; i++) {
ir_function *const f = shader_list[i]->symbols->get_function(name);
if (f == NULL)
continue;
ir_function_signature *sig = f->matching_signature(actual_parameters);
if ((sig == NULL) || !sig->is_defined)
continue;
/* If this function expects to bind to a built-in function and the
* signature that we found isn't a built-in, keep looking. Also keep
* looking if we expect a non-built-in but found a built-in.
*/
if (use_builtin != sig->is_builtin)
continue;
return sig;
}
return NULL;
}
bool
link_function_calls(gl_shader_program *prog, gl_shader *main,
gl_shader **shader_list, unsigned num_shaders)
{
call_link_visitor v(prog, main, shader_list, num_shaders);
v.run(main->ir);
return v.success;
}