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b6f15869b324ae64a00d0fe46fa3c8c62c1edb6c
third_party_mesa3d/src/glsl/linker.cpp
Kenneth Graunke b6f15869b3 glsl: Move is_built_in flag from ir_function_signature to ir_function. 
Also rename it to "is_builtin" for consistency.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
2010-08-26 09:19:48 -07:00

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/*
* 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.
*/
/**
* \file linker.cpp
* GLSL linker implementation
*
* Given a set of shaders that are to be linked to generate a final program,
* there are three distinct stages.
*
* In the first stage shaders are partitioned into groups based on the shader
* type. All shaders of a particular type (e.g., vertex shaders) are linked
* together.
*
* - Undefined references in each shader are resolve to definitions in
* another shader.
* - Types and qualifiers of uniforms, outputs, and global variables defined
* in multiple shaders with the same name are verified to be the same.
* - Initializers for uniforms and global variables defined
* in multiple shaders with the same name are verified to be the same.
*
* The result, in the terminology of the GLSL spec, is a set of shader
* executables for each processing unit.
*
* After the first stage is complete, a series of semantic checks are performed
* on each of the shader executables.
*
* - Each shader executable must define a \c main function.
* - Each vertex shader executable must write to \c gl_Position.
* - Each fragment shader executable must write to either \c gl_FragData or
* \c gl_FragColor.
*
* In the final stage individual shader executables are linked to create a
* complete exectuable.
*
* - Types of uniforms defined in multiple shader stages with the same name
* are verified to be the same.
* - Initializers for uniforms defined in multiple shader stages with the
* same name are verified to be the same.
* - Types and qualifiers of outputs defined in one stage are verified to
* be the same as the types and qualifiers of inputs defined with the same
* name in a later stage.
*
* \author Ian Romanick <ian.d.romanick@intel.com>
*/
#include <cstdlib>
#include <cstdio>
#include <cstdarg>
#include <climits>
extern "C" {
#include <talloc.h>
}
#include "main/core.h"
#include "glsl_symbol_table.h"
#include "ir.h"
#include "program.h"
#include "program/hash_table.h"
#include "linker.h"
#include "ir_optimization.h"
/**
* Visitor that determines whether or not a variable is ever written.
*/
class find_assignment_visitor : public ir_hierarchical_visitor {
public:
find_assignment_visitor(const char *name)
: name(name), found(false)
{
/* empty */
}
virtual ir_visitor_status visit_enter(ir_assignment *ir)
{
ir_variable *const var = ir->lhs->variable_referenced();
if (strcmp(name, var->name) == 0) {
found = true;
return visit_stop;
}
return visit_continue_with_parent;
}
virtual ir_visitor_status visit_enter(ir_call *ir)
{
exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();
foreach_iter(exec_list_iterator, iter, *ir) {
ir_rvalue *param_rval = (ir_rvalue *)iter.get();
ir_variable *sig_param = (ir_variable *)sig_iter.get();
if (sig_param->mode == ir_var_out ||
sig_param->mode == ir_var_inout) {
ir_variable *var = param_rval->variable_referenced();
if (var && strcmp(name, var->name) == 0) {
found = true;
return visit_stop;
}
}
sig_iter.next();
}
return visit_continue_with_parent;
}
bool variable_found()
{
return found;
}
private:
const char *name; /**< Find writes to a variable with this name. */
bool found; /**< Was a write to the variable found? */
};
/**
* Visitor that determines whether or not a variable is ever read.
*/
class find_deref_visitor : public ir_hierarchical_visitor {
public:
find_deref_visitor(const char *name)
: name(name), found(false)
{
/* empty */
}
virtual ir_visitor_status visit(ir_dereference_variable *ir)
{
if (strcmp(this->name, ir->var->name) == 0) {
this->found = true;
return visit_stop;
}
return visit_continue;
}
bool variable_found() const
{
return this->found;
}
private:
const char *name; /**< Find writes to a variable with this name. */
bool found; /**< Was a write to the variable found? */
};
void
linker_error_printf(gl_shader_program *prog, const char *fmt, ...)
{
va_list ap;
prog->InfoLog = talloc_strdup_append(prog->InfoLog, "error: ");
va_start(ap, fmt);
prog->InfoLog = talloc_vasprintf_append(prog->InfoLog, fmt, ap);
va_end(ap);
}
void
invalidate_variable_locations(gl_shader *sh, enum ir_variable_mode mode,
int generic_base)
{
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != (unsigned) mode))
continue;
/* Only assign locations for generic attributes / varyings / etc.
*/
if (var->location >= generic_base)
var->location = -1;
}
}
/**
* Determine the number of attribute slots required for a particular type
*
* This code is here because it implements the language rules of a specific
* GLSL version. Since it's a property of the language and not a property of
* types in general, it doesn't really belong in glsl_type.
*/
unsigned
count_attribute_slots(const glsl_type *t)
{
/* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
*
* "A scalar input counts the same amount against this limit as a vec4,
* so applications may want to consider packing groups of four
* unrelated float inputs together into a vector to better utilize the
* capabilities of the underlying hardware. A matrix input will use up
* multiple locations. The number of locations used will equal the
* number of columns in the matrix."
*
* The spec does not explicitly say how arrays are counted. However, it
* should be safe to assume the total number of slots consumed by an array
* is the number of entries in the array multiplied by the number of slots
* consumed by a single element of the array.
*/
if (t->is_array())
return t->array_size() * count_attribute_slots(t->element_type());
if (t->is_matrix())
return t->matrix_columns;
return 1;
}
/**
* Verify that a vertex shader executable meets all semantic requirements
*
* \param shader Vertex shader executable to be verified
*/
bool
validate_vertex_shader_executable(struct gl_shader_program *prog,
struct gl_shader *shader)
{
if (shader == NULL)
return true;
find_assignment_visitor find("gl_Position");
find.run(shader->ir);
if (!find.variable_found()) {
linker_error_printf(prog,
"vertex shader does not write to `gl_Position'\n");
return false;
}
return true;
}
/**
* Verify that a fragment shader executable meets all semantic requirements
*
* \param shader Fragment shader executable to be verified
*/
bool
validate_fragment_shader_executable(struct gl_shader_program *prog,
struct gl_shader *shader)
{
if (shader == NULL)
return true;
find_assignment_visitor frag_color("gl_FragColor");
find_assignment_visitor frag_data("gl_FragData");
frag_color.run(shader->ir);
frag_data.run(shader->ir);
if (frag_color.variable_found() && frag_data.variable_found()) {
linker_error_printf(prog, "fragment shader writes to both "
"`gl_FragColor' and `gl_FragData'\n");
return false;
}
return true;
}
/**
* Generate a string describing the mode of a variable
*/
static const char *
mode_string(const ir_variable *var)
{
switch (var->mode) {
case ir_var_auto:
return (var->read_only) ? "global constant" : "global variable";
case ir_var_uniform: return "uniform";
case ir_var_in: return "shader input";
case ir_var_out: return "shader output";
case ir_var_inout: return "shader inout";
case ir_var_temporary:
default:
assert(!"Should not get here.");
return "invalid variable";
}
}
/**
* Perform validation of global variables used across multiple shaders
*/
bool
cross_validate_globals(struct gl_shader_program *prog,
struct gl_shader **shader_list,
unsigned num_shaders,
bool uniforms_only)
{
/* Examine all of the uniforms in all of the shaders and cross validate
* them.
*/
glsl_symbol_table variables;
for (unsigned i = 0; i < num_shaders; i++) {
foreach_list(node, shader_list[i]->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if (var == NULL)
continue;
if (uniforms_only && (var->mode != ir_var_uniform))
continue;
/* Don't cross validate temporaries that are at global scope. These
* will eventually get pulled into the shaders 'main'.
*/
if (var->mode == ir_var_temporary)
continue;
/* If a global with this name has already been seen, verify that the
* new instance has the same type. In addition, if the globals have
* initializers, the values of the initializers must be the same.
*/
ir_variable *const existing = variables.get_variable(var->name);
if (existing != NULL) {
if (var->type != existing->type) {
linker_error_printf(prog, "%s `%s' declared as type "
"`%s' and type `%s'\n",
mode_string(var),
var->name, var->type->name,
existing->type->name);
return false;
}
/* FINISHME: Handle non-constant initializers.
*/
if (var->constant_value != NULL) {
if (existing->constant_value != NULL) {
if (!var->constant_value->has_value(existing->constant_value)) {
linker_error_printf(prog, "initializers for %s "
"`%s' have differing values\n",
mode_string(var), var->name);
return false;
}
} else
/* If the first-seen instance of a particular uniform did not
* have an initializer but a later instance does, copy the
* initializer to the version stored in the symbol table.
*/
/* FINISHME: This is wrong. The constant_value field should
* FINISHME: not be modified! Imagine a case where a shader
* FINISHME: without an initializer is linked in two different
* FINISHME: programs with shaders that have differing
* FINISHME: initializers. Linking with the first will
* FINISHME: modify the shader, and linking with the second
* FINISHME: will fail.
*/
existing->constant_value =
var->constant_value->clone(talloc_parent(existing), NULL);
}
} else
variables.add_variable(var->name, var);
}
}
return true;
}
/**
* Perform validation of uniforms used across multiple shader stages
*/
bool
cross_validate_uniforms(struct gl_shader_program *prog)
{
return cross_validate_globals(prog, prog->_LinkedShaders,
prog->_NumLinkedShaders, true);
}
/**
* Validate that outputs from one stage match inputs of another
*/
bool
cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
gl_shader *producer, gl_shader *consumer)
{
glsl_symbol_table parameters;
/* FINISHME: Figure these out dynamically. */
const char *const producer_stage = "vertex";
const char *const consumer_stage = "fragment";
/* Find all shader outputs in the "producer" stage.
*/
foreach_list(node, producer->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
/* FINISHME: For geometry shaders, this should also look for inout
* FINISHME: variables.
*/
if ((var == NULL) || (var->mode != ir_var_out))
continue;
parameters.add_variable(var->name, var);
}
/* Find all shader inputs in the "consumer" stage. Any variables that have
* matching outputs already in the symbol table must have the same type and
* qualifiers.
*/
foreach_list(node, consumer->ir) {
ir_variable *const input = ((ir_instruction *) node)->as_variable();
/* FINISHME: For geometry shaders, this should also look for inout
* FINISHME: variables.
*/
if ((input == NULL) || (input->mode != ir_var_in))
continue;
ir_variable *const output = parameters.get_variable(input->name);
if (output != NULL) {
/* Check that the types match between stages.
*/
if (input->type != output->type) {
linker_error_printf(prog,
"%s shader output `%s' delcared as "
"type `%s', but %s shader input declared "
"as type `%s'\n",
producer_stage, output->name,
output->type->name,
consumer_stage, input->type->name);
return false;
}
/* Check that all of the qualifiers match between stages.
*/
if (input->centroid != output->centroid) {
linker_error_printf(prog,
"%s shader output `%s' %s centroid qualifier, "
"but %s shader input %s centroid qualifier\n",
producer_stage,
output->name,
(output->centroid) ? "has" : "lacks",
consumer_stage,
(input->centroid) ? "has" : "lacks");
return false;
}
if (input->invariant != output->invariant) {
linker_error_printf(prog,
"%s shader output `%s' %s invariant qualifier, "
"but %s shader input %s invariant qualifier\n",
producer_stage,
output->name,
(output->invariant) ? "has" : "lacks",
consumer_stage,
(input->invariant) ? "has" : "lacks");
return false;
}
if (input->interpolation != output->interpolation) {
linker_error_printf(prog,
"%s shader output `%s' specifies %s "
"interpolation qualifier, "
"but %s shader input specifies %s "
"interpolation qualifier\n",
producer_stage,
output->name,
output->interpolation_string(),
consumer_stage,
input->interpolation_string());
return false;
}
}
}
return true;
}
/**
* Populates a shaders symbol table with all global declarations
*/
static void
populate_symbol_table(gl_shader *sh)
{
sh->symbols = new(sh) glsl_symbol_table;
foreach_list(node, sh->ir) {
ir_instruction *const inst = (ir_instruction *) node;
ir_variable *var;
ir_function *func;
if ((func = inst->as_function()) != NULL) {
sh->symbols->add_function(func->name, func);
} else if ((var = inst->as_variable()) != NULL) {
sh->symbols->add_variable(var->name, var);
}
}
}
/**
* Remap variables referenced in an instruction tree
*
* This is used when instruction trees are cloned from one shader and placed in
* another. These trees will contain references to \c ir_variable nodes that
* do not exist in the target shader. This function finds these \c ir_variable
* references and replaces the references with matching variables in the target
* shader.
*
* If there is no matching variable in the target shader, a clone of the
* \c ir_variable is made and added to the target shader. The new variable is
* added to \b both the instruction stream and the symbol table.
*
* \param inst IR tree that is to be processed.
* \param symbols Symbol table containing global scope symbols in the
* linked shader.
* \param instructions Instruction stream where new variable declarations
* should be added.
*/
void
remap_variables(ir_instruction *inst, struct gl_shader *target,
hash_table *temps)
{
class remap_visitor : public ir_hierarchical_visitor {
public:
remap_visitor(struct gl_shader *target,
hash_table *temps)
{
this->target = target;
this->symbols = target->symbols;
this->instructions = target->ir;
this->temps = temps;
}
virtual ir_visitor_status visit(ir_dereference_variable *ir)
{
if (ir->var->mode == ir_var_temporary) {
ir_variable *var = (ir_variable *) hash_table_find(temps, ir->var);
assert(var != NULL);
ir->var = var;
return visit_continue;
}
ir_variable *const existing =
this->symbols->get_variable(ir->var->name);
if (existing != NULL)
ir->var = existing;
else {
ir_variable *copy = ir->var->clone(this->target, NULL);
this->symbols->add_variable(copy->name, copy);
this->instructions->push_head(copy);
ir->var = copy;
}
return visit_continue;
}
private:
struct gl_shader *target;
glsl_symbol_table *symbols;
exec_list *instructions;
hash_table *temps;
};
remap_visitor v(target, temps);
inst->accept(&v);
}
/**
* Move non-declarations from one instruction stream to another
*
* The intended usage pattern of this function is to pass the pointer to the
* head sentinel of a list (i.e., a pointer to the list cast to an \c exec_node
* pointer) for \c last and \c false for \c make_copies on the first
* call. Successive calls pass the return value of the previous call for
* \c last and \c true for \c make_copies.
*
* \param instructions Source instruction stream
* \param last Instruction after which new instructions should be
* inserted in the target instruction stream
* \param make_copies Flag selecting whether instructions in \c instructions
* should be copied (via \c ir_instruction::clone) into the
* target list or moved.
*
* \return
* The new "last" instruction in the target instruction stream. This pointer
* is suitable for use as the \c last parameter of a later call to this
* function.
*/
exec_node *
move_non_declarations(exec_list *instructions, exec_node *last,
bool make_copies, gl_shader *target)
{
hash_table *temps = NULL;
if (make_copies)
temps = hash_table_ctor(0, hash_table_pointer_hash,
hash_table_pointer_compare);
foreach_list_safe(node, instructions) {
ir_instruction *inst = (ir_instruction *) node;
if (inst->as_function())
continue;
ir_variable *var = inst->as_variable();
if ((var != NULL) && (var->mode != ir_var_temporary))
continue;
assert(inst->as_assignment()
|| ((var != NULL) && (var->mode == ir_var_temporary)));
if (make_copies) {
inst = inst->clone(target, NULL);
if (var != NULL)
hash_table_insert(temps, inst, var);
else
remap_variables(inst, target, temps);
} else {
inst->remove();
}
last->insert_after(inst);
last = inst;
}
if (make_copies)
hash_table_dtor(temps);
return last;
}
/**
* Get the function signature for main from a shader
*/
static ir_function_signature *
get_main_function_signature(gl_shader *sh)
{
ir_function *const f = sh->symbols->get_function("main");
if (f != NULL) {
exec_list void_parameters;
/* Look for the 'void main()' signature and ensure that it's defined.
* This keeps the linker from accidentally pick a shader that just
* contains a prototype for main.
*
* We don't have to check for multiple definitions of main (in multiple
* shaders) because that would have already been caught above.
*/
ir_function_signature *sig = f->matching_signature(&void_parameters);
if ((sig != NULL) && sig->is_defined) {
return sig;
}
}
return NULL;
}
/**
* Combine a group of shaders for a single stage to generate a linked shader
*
* \note
* If this function is supplied a single shader, it is cloned, and the new
* shader is returned.
*/
static struct gl_shader *
link_intrastage_shaders(GLcontext *ctx,
struct gl_shader_program *prog,
struct gl_shader **shader_list,
unsigned num_shaders)
{
/* Check that global variables defined in multiple shaders are consistent.
*/
if (!cross_validate_globals(prog, shader_list, num_shaders, false))
return NULL;
/* Check that there is only a single definition of each function signature
* across all shaders.
*/
for (unsigned i = 0; i < (num_shaders - 1); i++) {
foreach_list(node, shader_list[i]->ir) {
ir_function *const f = ((ir_instruction *) node)->as_function();
if (f == NULL)
continue;
for (unsigned j = i + 1; j < num_shaders; j++) {
ir_function *const other =
shader_list[j]->symbols->get_function(f->name);
/* If the other shader has no function (and therefore no function
* signatures) with the same name, skip to the next shader.
*/
if (other == NULL)
continue;
foreach_iter (exec_list_iterator, iter, *f) {
ir_function_signature *sig =
(ir_function_signature *) iter.get();
if (!sig->is_defined || f->is_builtin)
continue;
ir_function_signature *other_sig =
other->exact_matching_signature(& sig->parameters);
if ((other_sig != NULL) && other_sig->is_defined
&& !other_sig->function()->is_builtin) {
linker_error_printf(prog,
"function `%s' is multiply defined",
f->name);
return NULL;
}
}
}
}
}
/* Find the shader that defines main, and make a clone of it.
*
* Starting with the clone, search for undefined references. If one is
* found, find the shader that defines it. Clone the reference and add
* it to the shader. Repeat until there are no undefined references or
* until a reference cannot be resolved.
*/
gl_shader *main = NULL;
for (unsigned i = 0; i < num_shaders; i++) {
if (get_main_function_signature(shader_list[i]) != NULL) {
main = shader_list[i];
break;
}
}
if (main == NULL) {
linker_error_printf(prog, "%s shader lacks `main'\n",
(shader_list[0]->Type == GL_VERTEX_SHADER)
? "vertex" : "fragment");
return NULL;
}
gl_shader *const linked = ctx->Driver.NewShader(NULL, 0, main->Type);
linked->ir = new(linked) exec_list;
clone_ir_list(linked, linked->ir, main->ir);
populate_symbol_table(linked);
/* The a pointer to the main function in the final linked shader (i.e., the
* copy of the original shader that contained the main function).
*/
ir_function_signature *const main_sig = get_main_function_signature(linked);
/* Move any instructions other than variable declarations or function
* declarations into main.
*/
exec_node *insertion_point =
move_non_declarations(linked->ir, (exec_node *) &main_sig->body, false,
linked);
for (unsigned i = 0; i < num_shaders; i++) {
if (shader_list[i] == main)
continue;
insertion_point = move_non_declarations(shader_list[i]->ir,
insertion_point, true, linked);
}
/* Resolve initializers for global variables in the linked shader.
*/
unsigned num_linking_shaders = num_shaders;
for (unsigned i = 0; i < num_shaders; i++)
num_linking_shaders += shader_list[i]->num_builtins_to_link;
gl_shader **linking_shaders =
(gl_shader **) calloc(num_linking_shaders, sizeof(gl_shader *));
memcpy(linking_shaders, shader_list,
sizeof(linking_shaders[0]) * num_shaders);
unsigned idx = num_shaders;
for (unsigned i = 0; i < num_shaders; i++) {
memcpy(&linking_shaders[idx], shader_list[i]->builtins_to_link,
sizeof(linking_shaders[0]) * shader_list[i]->num_builtins_to_link);
idx += shader_list[i]->num_builtins_to_link;
}
assert(idx == num_linking_shaders);
link_function_calls(prog, linked, linking_shaders, num_linking_shaders);
free(linking_shaders);
return linked;
}
struct uniform_node {
exec_node link;
struct gl_uniform *u;
unsigned slots;
};
/**
* Update the sizes of linked shader uniform arrays to the maximum
* array index used.
*
* From page 81 (page 95 of the PDF) of the OpenGL 2.1 spec:
*
* If one or more elements of an array are active,
* GetActiveUniform will return the name of the array in name,
* subject to the restrictions listed above. The type of the array
* is returned in type. The size parameter contains the highest
* array element index used, plus one. The compiler or linker
* determines the highest index used. There will be only one
* active uniform reported by the GL per uniform array.
*/
static void
update_uniform_array_sizes(struct gl_shader_program *prog)
{
for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
foreach_list(node, prog->_LinkedShaders[i]->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_uniform) ||
!var->type->is_array())
continue;
unsigned int size = var->max_array_access;
for (unsigned j = 0; j < prog->_NumLinkedShaders; j++) {
foreach_list(node2, prog->_LinkedShaders[j]->ir) {
ir_variable *other_var = ((ir_instruction *) node2)->as_variable();
if (!other_var)
continue;
if (strcmp(var->name, other_var->name) == 0 &&
other_var->max_array_access > size) {
size = other_var->max_array_access;
}
}
}
if (size + 1 != var->type->fields.array->length) {
var->type = glsl_type::get_array_instance(var->type->fields.array,
size + 1);
/* FINISHME: We should update the types of array
* dereferences of this variable now.
*/
}
}
}
}
static void
add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
const char *name, const glsl_type *type, GLenum shader_type,
unsigned *next_shader_pos, unsigned *total_uniforms)
{
if (type->is_record()) {
for (unsigned int i = 0; i < type->length; i++) {
const glsl_type *field_type = type->fields.structure[i].type;
char *field_name = talloc_asprintf(mem_ctx, "%s.%s", name,
type->fields.structure[i].name);
add_uniform(mem_ctx, uniforms, ht, field_name, field_type,
shader_type, next_shader_pos, total_uniforms);
}
} else {
uniform_node *n = (uniform_node *) hash_table_find(ht, name);
unsigned int vec4_slots;
const glsl_type *array_elem_type = NULL;
if (type->is_array()) {
array_elem_type = type->fields.array;
/* Array of structures. */
if (array_elem_type->is_record()) {
for (unsigned int i = 0; i < type->length; i++) {
char *elem_name = talloc_asprintf(mem_ctx, "%s[%d]", name, i);
add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type,
shader_type, next_shader_pos, total_uniforms);
}
return;
}
}
/* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out
* vectors to vec4 slots.
*/
if (type->is_array()) {
if (array_elem_type->is_sampler())
vec4_slots = type->length;
else
vec4_slots = type->length * array_elem_type->matrix_columns;
} else if (type->is_sampler()) {
vec4_slots = 1;
} else {
vec4_slots = type->matrix_columns;
}
if (n == NULL) {
n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform));
n->slots = vec4_slots;
n->u->Name = strdup(name);
n->u->Type = type;
n->u->VertPos = -1;
n->u->FragPos = -1;
n->u->GeomPos = -1;
(*total_uniforms)++;
hash_table_insert(ht, n, name);
uniforms->push_tail(& n->link);
}
switch (shader_type) {
case GL_VERTEX_SHADER:
n->u->VertPos = *next_shader_pos;
break;
case GL_FRAGMENT_SHADER:
n->u->FragPos = *next_shader_pos;
break;
case GL_GEOMETRY_SHADER:
n->u->GeomPos = *next_shader_pos;
break;
}
(*next_shader_pos) += vec4_slots;
}
}
void
assign_uniform_locations(struct gl_shader_program *prog)
{
/* */
exec_list uniforms;
unsigned total_uniforms = 0;
hash_table *ht = hash_table_ctor(32, hash_table_string_hash,
hash_table_string_compare);
void *mem_ctx = talloc_new(NULL);
update_uniform_array_sizes(prog);
for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
unsigned next_position = 0;
foreach_list(node, prog->_LinkedShaders[i]->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_uniform))
continue;
if (strncmp(var->name, "gl_", 3) == 0) {
/* At the moment, we don't allocate uniform locations for
* builtin uniforms. It's permitted by spec, and we'll
* likely switch to doing that at some point, but not yet.
*/
continue;
}
var->location = next_position;
add_uniform(mem_ctx, &uniforms, ht, var->name, var->type,
prog->_LinkedShaders[i]->Type,
&next_position, &total_uniforms);
}
}
talloc_free(mem_ctx);
gl_uniform_list *ul = (gl_uniform_list *)
calloc(1, sizeof(gl_uniform_list));
ul->Size = total_uniforms;
ul->NumUniforms = total_uniforms;
ul->Uniforms = (gl_uniform *) calloc(total_uniforms, sizeof(gl_uniform));
unsigned idx = 0;
uniform_node *next;
for (uniform_node *node = (uniform_node *) uniforms.head
; node->link.next != NULL
; node = next) {
next = (uniform_node *) node->link.next;
node->link.remove();
memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform));
idx++;
free(node->u);
free(node);
}
hash_table_dtor(ht);
prog->Uniforms = ul;
}
/**
* Find a contiguous set of available bits in a bitmask
*
* \param used_mask Bits representing used (1) and unused (0) locations
* \param needed_count Number of contiguous bits needed.
*
* \return
* Base location of the available bits on success or -1 on failure.
*/
int
find_available_slots(unsigned used_mask, unsigned needed_count)
{
unsigned needed_mask = (1 << needed_count) - 1;
const int max_bit_to_test = (8 * sizeof(used_mask)) - needed_count;
/* The comparison to 32 is redundant, but without it GCC emits "warning:
* cannot optimize possibly infinite loops" for the loop below.
*/
if ((needed_count == 0) || (max_bit_to_test < 0) || (max_bit_to_test > 32))
return -1;
for (int i = 0; i <= max_bit_to_test; i++) {
if ((needed_mask & ~used_mask) == needed_mask)
return i;
needed_mask <<= 1;
}
return -1;
}
bool
assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index)
{
/* Mark invalid attribute locations as being used.
*/
unsigned used_locations = (max_attribute_index >= 32)
? ~0 : ~((1 << max_attribute_index) - 1);
gl_shader *const sh = prog->_LinkedShaders[0];
assert(sh->Type == GL_VERTEX_SHADER);
/* Operate in a total of four passes.
*
* 1. Invalidate the location assignments for all vertex shader inputs.
*
* 2. Assign locations for inputs that have user-defined (via
* glBindVertexAttribLocation) locatoins.
*
* 3. Sort the attributes without assigned locations by number of slots
* required in decreasing order. Fragmentation caused by attribute
* locations assigned by the application may prevent large attributes
* from having enough contiguous space.
*
* 4. Assign locations to any inputs without assigned locations.
*/
invalidate_variable_locations(sh, ir_var_in, VERT_ATTRIB_GENERIC0);
if (prog->Attributes != NULL) {
for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
ir_variable *const var =
sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
/* Note: attributes that occupy multiple slots, such as arrays or
* matrices, may appear in the attrib array multiple times.
*/
if ((var == NULL) || (var->location != -1))
continue;
/* From page 61 of the OpenGL 4.0 spec:
*
* "LinkProgram will fail if the attribute bindings assigned by
* BindAttribLocation do not leave not enough space to assign a
* location for an active matrix attribute or an active attribute
* array, both of which require multiple contiguous generic
* attributes."
*
* Previous versions of the spec contain similar language but omit the
* bit about attribute arrays.
*
* Page 61 of the OpenGL 4.0 spec also says:
*
* "It is possible for an application to bind more than one
* attribute name to the same location. This is referred to as
* aliasing. This will only work if only one of the aliased
* attributes is active in the executable program, or if no path
* through the shader consumes more than one attribute of a set
* of attributes aliased to the same location. A link error can
* occur if the linker determines that every path through the
* shader consumes multiple aliased attributes, but
* implementations are not required to generate an error in this
* case."
*
* These two paragraphs are either somewhat contradictory, or I don't
* fully understand one or both of them.
*/
/* FINISHME: The code as currently written does not support attribute
* FINISHME: location aliasing (see comment above).
*/
const int attr = prog->Attributes->Parameters[i].StateIndexes[0];
const unsigned slots = count_attribute_slots(var->type);
/* Mask representing the contiguous slots that will be used by this
* attribute.
*/
const unsigned use_mask = (1 << slots) - 1;
/* Generate a link error if the set of bits requested for this
* attribute overlaps any previously allocated bits.
*/
if ((~(use_mask << attr) & used_locations) != used_locations) {
linker_error_printf(prog,
"insufficient contiguous attribute locations "
"available for vertex shader input `%s'",
var->name);
return false;
}
var->location = VERT_ATTRIB_GENERIC0 + attr;
used_locations |= (use_mask << attr);
}
}
/* Temporary storage for the set of attributes that need locations assigned.
*/
struct temp_attr {
unsigned slots;
ir_variable *var;
/* Used below in the call to qsort. */
static int compare(const void *a, const void *b)
{
const temp_attr *const l = (const temp_attr *) a;
const temp_attr *const r = (const temp_attr *) b;
/* Reversed because we want a descending order sort below. */
return r->slots - l->slots;
}
} to_assign[16];
unsigned num_attr = 0;
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_in))
continue;
/* The location was explicitly assigned, nothing to do here.
*/
if (var->location != -1)
continue;
to_assign[num_attr].slots = count_attribute_slots(var->type);
to_assign[num_attr].var = var;
num_attr++;
}
/* If all of the attributes were assigned locations by the application (or
* are built-in attributes with fixed locations), return early. This should
* be the common case.
*/
if (num_attr == 0)
return true;
qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
/* VERT_ATTRIB_GENERIC0 is a psdueo-alias for VERT_ATTRIB_POS. It can only
* be explicitly assigned by via glBindAttribLocation. Mark it as reserved
* to prevent it from being automatically allocated below.
*/
find_deref_visitor find("gl_Vertex");
find.run(sh->ir);
if (find.variable_found())
used_locations |= (1 << 0);
for (unsigned i = 0; i < num_attr; i++) {
/* Mask representing the contiguous slots that will be used by this
* attribute.
*/
const unsigned use_mask = (1 << to_assign[i].slots) - 1;
int location = find_available_slots(used_locations, to_assign[i].slots);
if (location < 0) {
linker_error_printf(prog,
"insufficient contiguous attribute locations "
"available for vertex shader input `%s'",
to_assign[i].var->name);
return false;
}
to_assign[i].var->location = VERT_ATTRIB_GENERIC0 + location;
used_locations |= (use_mask << location);
}
return true;
}
/**
* Demote shader outputs that are not read to being just plain global variables
*/
void
demote_unread_shader_outputs(gl_shader *sh)
{
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_out))
continue;
/* An 'out' variable is only really a shader output if its value is read
* by the following stage.
*/
if (var->location == -1) {
var->mode = ir_var_auto;
}
}
}
void
assign_varying_locations(struct gl_shader_program *prog,
gl_shader *producer, gl_shader *consumer)
{
/* FINISHME: Set dynamically when geometry shader support is added. */
unsigned output_index = VERT_RESULT_VAR0;
unsigned input_index = FRAG_ATTRIB_VAR0;
/* Operate in a total of three passes.
*
* 1. Assign locations for any matching inputs and outputs.
*
* 2. Mark output variables in the producer that do not have locations as
* not being outputs. This lets the optimizer eliminate them.
*
* 3. Mark input variables in the consumer that do not have locations as
* not being inputs. This lets the optimizer eliminate them.
*/
invalidate_variable_locations(producer, ir_var_out, VERT_RESULT_VAR0);
invalidate_variable_locations(consumer, ir_var_in, FRAG_ATTRIB_VAR0);
foreach_list(node, producer->ir) {
ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
if ((output_var == NULL) || (output_var->mode != ir_var_out)
|| (output_var->location != -1))
continue;
ir_variable *const input_var =
consumer->symbols->get_variable(output_var->name);
if ((input_var == NULL) || (input_var->mode != ir_var_in))
continue;
assert(input_var->location == -1);
/* FINISHME: Location assignment will need some changes when arrays,
* FINISHME: matrices, and structures are allowed as shader inputs /
* FINISHME: outputs.
*/
output_var->location = output_index;
input_var->location = input_index;
output_index++;
input_index++;
}
demote_unread_shader_outputs(producer);
foreach_list(node, consumer->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_in))
continue;
if (var->location == -1) {
if (prog->Version <= 120) {
/* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
*
* Only those varying variables used (i.e. read) in
* the fragment shader executable must be written to
* by the vertex shader executable; declaring
* superfluous varying variables in a vertex shader is
* permissible.
*
* We interpret this text as meaning that the VS must
* write the variable for the FS to read it. See
* "glsl1-varying read but not written" in piglit.
*/
linker_error_printf(prog, "fragment shader varying %s not written "
"by vertex shader\n.", var->name);
prog->LinkStatus = false;
}
/* An 'in' variable is only really a shader input if its
* value is written by the previous stage.
*/
var->mode = ir_var_auto;
}
}
}
void
link_shaders(GLcontext *ctx, struct gl_shader_program *prog)
{
prog->LinkStatus = false;
prog->Validated = false;
prog->_Used = false;
if (prog->InfoLog != NULL)
talloc_free(prog->InfoLog);
prog->InfoLog = talloc_strdup(NULL, "");
/* Separate the shaders into groups based on their type.
*/
struct gl_shader **vert_shader_list;
unsigned num_vert_shaders = 0;
struct gl_shader **frag_shader_list;
unsigned num_frag_shaders = 0;
vert_shader_list = (struct gl_shader **)
calloc(2 * prog->NumShaders, sizeof(struct gl_shader *));
frag_shader_list = &vert_shader_list[prog->NumShaders];
unsigned min_version = UINT_MAX;
unsigned max_version = 0;
for (unsigned i = 0; i < prog->NumShaders; i++) {
min_version = MIN2(min_version, prog->Shaders[i]->Version);
max_version = MAX2(max_version, prog->Shaders[i]->Version);
switch (prog->Shaders[i]->Type) {
case GL_VERTEX_SHADER:
vert_shader_list[num_vert_shaders] = prog->Shaders[i];
num_vert_shaders++;
break;
case GL_FRAGMENT_SHADER:
frag_shader_list[num_frag_shaders] = prog->Shaders[i];
num_frag_shaders++;
break;
case GL_GEOMETRY_SHADER:
/* FINISHME: Support geometry shaders. */
assert(prog->Shaders[i]->Type != GL_GEOMETRY_SHADER);
break;
}
}
/* Previous to GLSL version 1.30, different compilation units could mix and
* match shading language versions. With GLSL 1.30 and later, the versions
* of all shaders must match.
*/
assert(min_version >= 110);
assert(max_version <= 130);
if ((max_version >= 130) && (min_version != max_version)) {
linker_error_printf(prog, "all shaders must use same shading "
"language version\n");
goto done;
}
prog->Version = max_version;
for (unsigned int i = 0; i < prog->_NumLinkedShaders; i++) {
ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
}
/* Link all shaders for a particular stage and validate the result.
*/
prog->_NumLinkedShaders = 0;
if (num_vert_shaders > 0) {
gl_shader *const sh =
link_intrastage_shaders(ctx, prog, vert_shader_list, num_vert_shaders);
if (sh == NULL)
goto done;
if (!validate_vertex_shader_executable(prog, sh))
goto done;
prog->_LinkedShaders[prog->_NumLinkedShaders] = sh;
prog->_NumLinkedShaders++;
}
if (num_frag_shaders > 0) {
gl_shader *const sh =
link_intrastage_shaders(ctx, prog, frag_shader_list, num_frag_shaders);
if (sh == NULL)
goto done;
if (!validate_fragment_shader_executable(prog, sh))
goto done;
prog->_LinkedShaders[prog->_NumLinkedShaders] = sh;
prog->_NumLinkedShaders++;
}
/* Here begins the inter-stage linking phase. Some initial validation is
* performed, then locations are assigned for uniforms, attributes, and
* varyings.
*/
if (cross_validate_uniforms(prog)) {
/* Validate the inputs of each stage with the output of the preceeding
* stage.
*/
for (unsigned i = 1; i < prog->_NumLinkedShaders; i++) {
if (!cross_validate_outputs_to_inputs(prog,
prog->_LinkedShaders[i - 1],
prog->_LinkedShaders[i]))
goto done;
}
prog->LinkStatus = true;
}
/* Do common optimization before assigning storage for attributes,
* uniforms, and varyings. Later optimization could possibly make
* some of that unused.
*/
for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
while (do_common_optimization(prog->_LinkedShaders[i]->ir, true))
;
}
assign_uniform_locations(prog);
if (prog->_LinkedShaders[0]->Type == GL_VERTEX_SHADER) {
/* FINISHME: The value of the max_attribute_index parameter is
* FINISHME: implementation dependent based on the value of
* FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
* FINISHME: at least 16, so hardcode 16 for now.
*/
if (!assign_attribute_locations(prog, 16))
goto done;
if (prog->_NumLinkedShaders == 1)
demote_unread_shader_outputs(prog->_LinkedShaders[0]);
}
for (unsigned i = 1; i < prog->_NumLinkedShaders; i++)
assign_varying_locations(prog,
prog->_LinkedShaders[i - 1],
prog->_LinkedShaders[i]);
/* FINISHME: Assign fragment shader output locations. */
done:
free(vert_shader_list);
}
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