/*
* 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 "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"
#include "link_varyings.h"
#include "ir_optimization.h"
extern "C" {
#include "main/shaderobj.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->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_function_out ||
sig_param->mode == ir_var_function_inout) {
ir_variable *var = param_rval->variable_referenced();
if (var && strcmp(name, var->name) == 0) {
found = true;
return visit_stop;
}
}
sig_iter.next();
}
if (ir->return_deref != NULL) {
ir_variable *const var = ir->return_deref->variable_referenced();
if (strcmp(name, var->name) == 0) {
found = true;
return visit_stop;
}
}
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(gl_shader_program *prog, const char *fmt, ...)
{
va_list ap;
ralloc_strcat(&prog->InfoLog, "error: ");
va_start(ap, fmt);
ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
va_end(ap);
prog->LinkStatus = false;
}
void
linker_warning(gl_shader_program *prog, const char *fmt, ...)
{
va_list ap;
ralloc_strcat(&prog->InfoLog, "error: ");
va_start(ap, fmt);
ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
va_end(ap);
}
/**
* Given a string identifying a program resource, break it into a base name
* and an optional array index in square brackets.
*
* If an array index is present, \c out_base_name_end is set to point to the
* "[" that precedes the array index, and the array index itself is returned
* as a long.
*
* If no array index is present (or if the array index is negative or
* mal-formed), \c out_base_name_end, is set to point to the null terminator
* at the end of the input string, and -1 is returned.
*
* Only the final array index is parsed; if the string contains other array
* indices (or structure field accesses), they are left in the base name.
*
* No attempt is made to check that the base name is properly formed;
* typically the caller will look up the base name in a hash table, so
* ill-formed base names simply turn into hash table lookup failures.
*/
long
parse_program_resource_name(const GLchar *name,
const GLchar **out_base_name_end)
{
/* Section 7.3.1 ("Program Interfaces") of the OpenGL 4.3 spec says:
*
* "When an integer array element or block instance number is part of
* the name string, it will be specified in decimal form without a "+"
* or "-" sign or any extra leading zeroes. Additionally, the name
* string will not include white space anywhere in the string."
*/
const size_t len = strlen(name);
*out_base_name_end = name + len;
if (len == 0 || name[len-1] != ']')
return -1;
/* Walk backwards over the string looking for a non-digit character. This
* had better be the opening bracket for an array index.
*
* Initially, i specifies the location of the ']'. Since the string may
* contain only the ']' charcater, walk backwards very carefully.
*/
unsigned i;
for (i = len - 1; (i > 0) && isdigit(name[i-1]); --i)
/* empty */ ;
if ((i == 0) || name[i-1] != '[')
return -1;
long array_index = strtol(&name[i], NULL, 10);
if (array_index < 0)
return -1;
*out_base_name_end = name + (i - 1);
return array_index;
}
void
link_invalidate_variable_locations(gl_shader *sh, int input_base,
int output_base)
{
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if (var == NULL)
continue;
int base;
switch (var->mode) {
case ir_var_shader_in:
base = input_base;
break;
case ir_var_shader_out:
base = output_base;
break;
default:
continue;
}
/* Only assign locations for generic attributes / varyings / etc.
*/
if ((var->location >= base) && !var->explicit_location)
var->location = -1;
if ((var->location == -1) && !var->explicit_location) {
var->is_unmatched_generic_inout = 1;
var->location_frac = 0;
} else {
var->is_unmatched_generic_inout = 0;
}
}
}
/**
* 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.
*
* Also sets prog->Vert.UsesClipDistance and prog->Vert.ClipDistanceArraySize
* as a side effect.
*
* \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;
/* From the GLSL 1.10 spec, page 48:
*
* "The variable gl_Position is available only in the vertex
* language and is intended for writing the homogeneous vertex
* position. All executions of a well-formed vertex shader
* executable must write a value into this variable. [...] The
* variable gl_Position is available only in the vertex
* language and is intended for writing the homogeneous vertex
* position. All executions of a well-formed vertex shader
* executable must write a value into this variable."
*
* while in GLSL 1.40 this text is changed to:
*
* "The variable gl_Position is available only in the vertex
* language and is intended for writing the homogeneous vertex
* position. It can be written at any time during shader
* execution. It may also be read back by a vertex shader
* after being written. This value will be used by primitive
* assembly, clipping, culling, and other fixed functionality
* operations, if present, that operate on primitives after
* vertex processing has occurred. Its value is undefined if
* the vertex shader executable does not write gl_Position."
*
* GLSL ES 3.00 is similar to GLSL 1.40--failing to write to gl_Position is
* not an error.
*/
if (prog->Version < (prog->IsES ? 300 : 140)) {
find_assignment_visitor find("gl_Position");
find.run(shader->ir);
if (!find.variable_found()) {
linker_error(prog, "vertex shader does not write to `gl_Position'\n");
return false;
}
}
prog->Vert.ClipDistanceArraySize = 0;
if (!prog->IsES && prog->Version >= 130) {
/* From section 7.1 (Vertex Shader Special Variables) of the
* GLSL 1.30 spec:
*
* "It is an error for a shader to statically write both
* gl_ClipVertex and gl_ClipDistance."
*
* This does not apply to GLSL ES shaders, since GLSL ES defines neither
* gl_ClipVertex nor gl_ClipDistance.
*/
find_assignment_visitor clip_vertex("gl_ClipVertex");
find_assignment_visitor clip_distance("gl_ClipDistance");
clip_vertex.run(shader->ir);
clip_distance.run(shader->ir);
if (clip_vertex.variable_found() && clip_distance.variable_found()) {
linker_error(prog, "vertex shader writes to both `gl_ClipVertex' "
"and `gl_ClipDistance'\n");
return false;
}
prog->Vert.UsesClipDistance = clip_distance.variable_found();
ir_variable *clip_distance_var =
shader->symbols->get_variable("gl_ClipDistance");
if (clip_distance_var)
prog->Vert.ClipDistanceArraySize = clip_distance_var->type->length;
}
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(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_shader_in: return "shader input";
case ir_var_shader_out: return "shader output";
case ir_var_const_in:
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++) {
if (shader_list[i] == NULL)
continue;
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) {
/* Consider the types to be "the same" if both types are arrays
* of the same type and one of the arrays is implicitly sized.
* In addition, set the type of the linked variable to the
* explicitly sized array.
*/
if (var->type->is_array()
&& existing->type->is_array()
&& (var->type->fields.array == existing->type->fields.array)
&& ((var->type->length == 0)
|| (existing->type->length == 0))) {
if (var->type->length != 0) {
existing->type = var->type;
}
} else {
linker_error(prog, "%s `%s' declared as type "
"`%s' and type `%s'\n",
mode_string(var),
var->name, var->type->name,
existing->type->name);
return false;
}
}
if (var->explicit_location) {
if (existing->explicit_location
&& (var->location != existing->location)) {
linker_error(prog, "explicit locations for %s "
"`%s' have differing values\n",
mode_string(var), var->name);
return false;
}
existing->location = var->location;
existing->explicit_location = true;
}
/* From the GLSL 4.20 specification:
* "A link error will result if two compilation units in a program
* specify different integer-constant bindings for the same
* opaque-uniform name. However, it is not an error to specify a
* binding on some but not all declarations for the same name"
*/
if (var->explicit_binding) {
if (existing->explicit_binding &&
var->binding != existing->binding) {
linker_error(prog, "explicit bindings for %s "
"`%s' have differing values\n",
mode_string(var), var->name);
return false;
}
existing->binding = var->binding;
existing->explicit_binding = true;
}
/* Validate layout qualifiers for gl_FragDepth.
*
* From the AMD/ARB_conservative_depth specs:
*
* "If gl_FragDepth is redeclared in any fragment shader in a
* program, it must be redeclared in all fragment shaders in
* that program that have static assignments to
* gl_FragDepth. All redeclarations of gl_FragDepth in all
* fragment shaders in a single program must have the same set
* of qualifiers."
*/
if (strcmp(var->name, "gl_FragDepth") == 0) {
bool layout_declared = var->depth_layout != ir_depth_layout_none;
bool layout_differs =
var->depth_layout != existing->depth_layout;
if (layout_declared && layout_differs) {
linker_error(prog,
"All redeclarations of gl_FragDepth in all "
"fragment shaders in a single program must have "
"the same set of qualifiers.");
}
if (var->used && layout_differs) {
linker_error(prog,
"If gl_FragDepth is redeclared with a layout "
"qualifier in any fragment shader, it must be "
"redeclared with the same layout qualifier in "
"all fragment shaders that have assignments to "
"gl_FragDepth");
}
}
/* Page 35 (page 41 of the PDF) of the GLSL 4.20 spec says:
*
* "If a shared global has multiple initializers, the
* initializers must all be constant expressions, and they
* must all have the same value. Otherwise, a link error will
* result. (A shared global having only one initializer does
* not require that initializer to be a constant expression.)"
*
* Previous to 4.20 the GLSL spec simply said that initializers
* must have the same value. In this case of non-constant
* initializers, this was impossible to determine. As a result,
* no vendor actually implemented that behavior. The 4.20
* behavior matches the implemented behavior of at least one other
* vendor, so we'll implement that for all GLSL versions.
*/
if (var->constant_initializer != NULL) {
if (existing->constant_initializer != NULL) {
if (!var->constant_initializer->has_value(existing->constant_initializer)) {
linker_error(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_initializer =
var->constant_initializer->clone(ralloc_parent(existing),
NULL);
}
}
if (var->has_initializer) {
if (existing->has_initializer
&& (var->constant_initializer == NULL
|| existing->constant_initializer == NULL)) {
linker_error(prog,
"shared global variable `%s' has multiple "
"non-constant initializers.\n",
var->name);
return false;
}
/* Some instance had an initializer, so keep track of that. In
* this location, all sorts of initializers (constant or
* otherwise) will propagate the existence to the variable
* stored in the symbol table.
*/
existing->has_initializer = true;
}
if (existing->invariant != var->invariant) {
linker_error(prog, "declarations for %s `%s' have "
"mismatching invariant qualifiers\n",
mode_string(var), var->name);
return false;
}
if (existing->centroid != var->centroid) {
linker_error(prog, "declarations for %s `%s' have "
"mismatching centroid qualifiers\n",
mode_string(var), var->name);
return false;
}
} else
variables.add_variable(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,
MESA_SHADER_TYPES, true);
}
/**
* Accumulates the array of prog->UniformBlocks and checks that all
* definitons of blocks agree on their contents.
*/
static bool
interstage_cross_validate_uniform_blocks(struct gl_shader_program *prog)
{
unsigned max_num_uniform_blocks = 0;
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i])
max_num_uniform_blocks += prog->_LinkedShaders[i]->NumUniformBlocks;
}
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
struct gl_shader *sh = prog->_LinkedShaders[i];
prog->UniformBlockStageIndex[i] = ralloc_array(prog, int,
max_num_uniform_blocks);
for (unsigned int j = 0; j < max_num_uniform_blocks; j++)
prog->UniformBlockStageIndex[i][j] = -1;
if (sh == NULL)
continue;
for (unsigned int j = 0; j < sh->NumUniformBlocks; j++) {
int index = link_cross_validate_uniform_block(prog,
&prog->UniformBlocks,
&prog->NumUniformBlocks,
&sh->UniformBlocks[j]);
if (index == -1) {
linker_error(prog, "uniform block `%s' has mismatching definitions",
sh->UniformBlocks[j].Name);
return false;
}
prog->UniformBlockStageIndex[i][index] = j;
}
}
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);
} else if ((var = inst->as_variable()) != NULL) {
sh->symbols->add_variable(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);
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()
|| inst->as_call()
|| inst->as_if() /* for initializers with the ?: operator */
|| ((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;
}
/**
* This class is only used in link_intrastage_shaders() below but declaring
* it inside that function leads to compiler warnings with some versions of
* gcc.
*/
class array_sizing_visitor : public ir_hierarchical_visitor {
public:
virtual ir_visitor_status visit(ir_variable *var)
{
if (var->type->is_array() && (var->type->length == 0)) {
const glsl_type *type =
glsl_type::get_array_instance(var->type->fields.array,
var->max_array_access + 1);
assert(type != NULL);
var->type = type;
}
return visit_continue;
}
};
/**
* 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(void *mem_ctx,
struct gl_context *ctx,
struct gl_shader_program *prog,
struct gl_shader **shader_list,
unsigned num_shaders)
{
struct gl_uniform_block *uniform_blocks = NULL;
/* Check that global variables defined in multiple shaders are consistent.
*/
if (!cross_validate_globals(prog, shader_list, num_shaders, false))
return NULL;
/* Check that interface blocks defined in multiple shaders are consistent.
*/
if (!validate_intrastage_interface_blocks((const gl_shader **)shader_list,
num_shaders))
return NULL;
/* Check that uniform blocks between shaders for a stage agree. */
const int num_uniform_blocks =
link_uniform_blocks(mem_ctx, prog, shader_list, num_shaders,
&uniform_blocks);
if (num_uniform_blocks < 0)
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 || sig->is_builtin)
continue;
ir_function_signature *other_sig =
other->exact_matching_signature(& sig->parameters);
if ((other_sig != NULL) && other_sig->is_defined
&& !other_sig->is_builtin) {
linker_error(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(prog, "%s shader lacks `main'\n",
_mesa_glsl_shader_target_name(shader_list[0]->Type));
return NULL;
}
gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type);
linked->ir = new(linked) exec_list;
clone_ir_list(mem_ctx, linked->ir, main->ir);
linked->UniformBlocks = uniform_blocks;
linked->NumUniformBlocks = num_uniform_blocks;
ralloc_steal(linked, linked->UniformBlocks);
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);
if (!link_function_calls(prog, linked, linking_shaders,
num_linking_shaders)) {
ctx->Driver.DeleteShader(ctx, linked);
linked = NULL;
}
free(linking_shaders);
/* At this point linked should contain all of the linked IR, so
* validate it to make sure nothing went wrong.
*/
if (linked)
validate_ir_tree(linked->ir);
/* Make a pass over all variable declarations to ensure that arrays with
* unspecified sizes have a size specified. The size is inferred from the
* max_array_access field.
*/
if (linked != NULL) {
array_sizing_visitor v;
v.run(linked->ir);
}
return linked;
}
/**
* 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_array_sizes(struct gl_shader_program *prog)
{
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] == NULL)
continue;
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->mode != ir_var_shader_in &&
var->mode != ir_var_shader_out) ||
!var->type->is_array())
continue;
/* GL_ARB_uniform_buffer_object says that std140 uniforms
* will not be eliminated. Since we always do std140, just
* don't resize arrays in UBOs.
*/
if (var->is_in_uniform_block())
continue;
unsigned int size = var->max_array_access;
for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
if (prog->_LinkedShaders[j] == NULL)
continue;
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->length) {
/* If this is a built-in uniform (i.e., it's backed by some
* fixed-function state), adjust the number of state slots to
* match the new array size. The number of slots per array entry
* is not known. It seems safe to assume that the total number of
* slots is an integer multiple of the number of array elements.
* Determine the number of slots per array element by dividing by
* the old (total) size.
*/
if (var->num_state_slots > 0) {
var->num_state_slots = (size + 1)
* (var->num_state_slots / var->type->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.
*/
}
}
}
}
/**
* 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;
}
/**
* Assign locations for either VS inputs for FS outputs
*
* \param prog Shader program whose variables need locations assigned
* \param target_index Selector for the program target to receive location
* assignmnets. Must be either \c MESA_SHADER_VERTEX or
* \c MESA_SHADER_FRAGMENT.
* \param max_index Maximum number of generic locations. This corresponds
* to either the maximum number of draw buffers or the
* maximum number of generic attributes.
*
* \return
* If locations are successfully assigned, true is returned. Otherwise an
* error is emitted to the shader link log and false is returned.
*/
bool
assign_attribute_or_color_locations(gl_shader_program *prog,
unsigned target_index,
unsigned max_index)
{
/* Mark invalid locations as being used.
*/
unsigned used_locations = (max_index >= 32)
? ~0 : ~((1 << max_index) - 1);
assert((target_index == MESA_SHADER_VERTEX)
|| (target_index == MESA_SHADER_FRAGMENT));
gl_shader *const sh = prog->_LinkedShaders[target_index];
if (sh == NULL)
return true;
/* 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) locations and outputs that have
* user-defined locations (via glBindFragDataLocation).
*
* 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.
*/
const int generic_base = (target_index == MESA_SHADER_VERTEX)
? (int) VERT_ATTRIB_GENERIC0 : (int) FRAG_RESULT_DATA0;
const enum ir_variable_mode direction =
(target_index == MESA_SHADER_VERTEX)
? ir_var_shader_in : ir_var_shader_out;
/* 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 != (unsigned) direction))
continue;
if (var->explicit_location) {
if ((var->location >= (int)(max_index + generic_base))
|| (var->location < 0)) {
linker_error(prog,
"invalid explicit location %d specified for `%s'\n",
(var->location < 0)
? var->location : var->location - generic_base,
var->name);
return false;
}
} else if (target_index == MESA_SHADER_VERTEX) {
unsigned binding;
if (prog->AttributeBindings->get(binding, var->name)) {
assert(binding >= VERT_ATTRIB_GENERIC0);
var->location = binding;
var->is_unmatched_generic_inout = 0;
}
} else if (target_index == MESA_SHADER_FRAGMENT) {
unsigned binding;
unsigned index;
if (prog->FragDataBindings->get(binding, var->name)) {
assert(binding >= FRAG_RESULT_DATA0);
var->location = binding;
var->is_unmatched_generic_inout = 0;
if (prog->FragDataIndexBindings->get(index, var->name)) {
var->index = index;
}
}
}
/* If the variable is not a built-in and has a location statically
* assigned in the shader (presumably via a layout qualifier), make sure
* that it doesn't collide with other assigned locations. Otherwise,
* add it to the list of variables that need linker-assigned locations.
*/
const unsigned slots = count_attribute_slots(var->type);
if (var->location != -1) {
if (var->location >= generic_base && var->index < 1) {
/* 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
* FINISHME: attribute location aliasing (see comment above).
*/
/* Mask representing the contiguous slots that will be used by
* this attribute.
*/
const unsigned attr = var->location - generic_base;
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) {
const char *const string = (target_index == MESA_SHADER_VERTEX)
? "vertex shader input" : "fragment shader output";
linker_error(prog,
"insufficient contiguous locations "
"available for %s `%s' %d %d %d", string,
var->name, used_locations, use_mask, attr);
return false;
}
used_locations |= (use_mask << attr);
}
continue;
}
to_assign[num_attr].slots = slots;
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);
if (target_index == MESA_SHADER_VERTEX) {
/* VERT_ATTRIB_GENERIC0 is a pseudo-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) {
const char *const string = (target_index == MESA_SHADER_VERTEX)
? "vertex shader input" : "fragment shader output";
linker_error(prog,
"insufficient contiguous locations "
"available for %s `%s'",
string, to_assign[i].var->name);
return false;
}
to_assign[i].var->location = generic_base + location;
to_assign[i].var->is_unmatched_generic_inout = 0;
used_locations |= (use_mask << location);
}
return true;
}
/**
* Demote shader inputs and outputs that are not used in other stages
*/
void
demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
{
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != int(mode)))
continue;
/* A shader 'in' or 'out' variable is only really an input or output if
* its value is used by other shader stages. This will cause the variable
* to have a location assigned.
*/
if (var->is_unmatched_generic_inout) {
var->mode = ir_var_auto;
}
}
}
/**
* Store the gl_FragDepth layout in the gl_shader_program struct.
*/
static void
store_fragdepth_layout(struct gl_shader_program *prog)
{
if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) {
return;
}
struct exec_list *ir = prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->ir;
/* We don't look up the gl_FragDepth symbol directly because if
* gl_FragDepth is not used in the shader, it's removed from the IR.
* However, the symbol won't be removed from the symbol table.
*
* We're only interested in the cases where the variable is NOT removed
* from the IR.
*/
foreach_list(node, ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if (var == NULL || var->mode != ir_var_shader_out) {
continue;
}
if (strcmp(var->name, "gl_FragDepth") == 0) {
switch (var->depth_layout) {
case ir_depth_layout_none:
prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_NONE;
return;
case ir_depth_layout_any:
prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_ANY;
return;
case ir_depth_layout_greater:
prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_GREATER;
return;
case ir_depth_layout_less:
prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_LESS;
return;
case ir_depth_layout_unchanged:
prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_UNCHANGED;
return;
default:
assert(0);
return;
}
}
}
}
/**
* Validate the resources used by a program versus the implementation limits
*/
static bool
check_resources(struct gl_context *ctx, struct gl_shader_program *prog)
{
static const char *const shader_names[MESA_SHADER_TYPES] = {
"vertex", "geometry", "fragment"
};
const unsigned max_samplers[MESA_SHADER_TYPES] = {
ctx->Const.VertexProgram.MaxTextureImageUnits,
ctx->Const.GeometryProgram.MaxTextureImageUnits,
ctx->Const.FragmentProgram.MaxTextureImageUnits
};
const unsigned max_default_uniform_components[MESA_SHADER_TYPES] = {
ctx->Const.VertexProgram.MaxUniformComponents,
ctx->Const.GeometryProgram.MaxUniformComponents,
ctx->Const.FragmentProgram.MaxUniformComponents
};
const unsigned max_combined_uniform_components[MESA_SHADER_TYPES] = {
ctx->Const.VertexProgram.MaxCombinedUniformComponents,
ctx->Const.GeometryProgram.MaxCombinedUniformComponents,
ctx->Const.FragmentProgram.MaxCombinedUniformComponents
};
const unsigned max_uniform_blocks[MESA_SHADER_TYPES] = {
ctx->Const.VertexProgram.MaxUniformBlocks,
ctx->Const.GeometryProgram.MaxUniformBlocks,
ctx->Const.FragmentProgram.MaxUniformBlocks
};
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
struct gl_shader *sh = prog->_LinkedShaders[i];
if (sh == NULL)
continue;
if (sh->num_samplers > max_samplers[i]) {
linker_error(prog, "Too many %s shader texture samplers",
shader_names[i]);
}
if (sh->num_uniform_components > max_default_uniform_components[i]) {
if (ctx->Const.GLSLSkipStrictMaxUniformLimitCheck) {
linker_warning(prog, "Too many %s shader default uniform block "
"components, but the driver will try to optimize "
"them out; this is non-portable out-of-spec "
"behavior\n",
shader_names[i]);
} else {
linker_error(prog, "Too many %s shader default uniform block "
"components",
shader_names[i]);
}
}
if (sh->num_combined_uniform_components >
max_combined_uniform_components[i]) {
if (ctx->Const.GLSLSkipStrictMaxUniformLimitCheck) {
linker_warning(prog, "Too many %s shader uniform components, "
"but the driver will try to optimize them out; "
"this is non-portable out-of-spec behavior\n",
shader_names[i]);
} else {
linker_error(prog, "Too many %s shader uniform components",
shader_names[i]);
}
}
}
unsigned blocks[MESA_SHADER_TYPES] = {0};
unsigned total_uniform_blocks = 0;
for (unsigned i = 0; i < prog->NumUniformBlocks; i++) {
for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
if (prog->UniformBlockStageIndex[j][i] != -1) {
blocks[j]++;
total_uniform_blocks++;
}
}
if (total_uniform_blocks > ctx->Const.MaxCombinedUniformBlocks) {
linker_error(prog, "Too many combined uniform blocks (%d/%d)",
prog->NumUniformBlocks,
ctx->Const.MaxCombinedUniformBlocks);
} else {
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
if (blocks[i] > max_uniform_blocks[i]) {
linker_error(prog, "Too many %s uniform blocks (%d/%d)",
shader_names[i],
blocks[i],
max_uniform_blocks[i]);
break;
}
}
}
}
return prog->LinkStatus;
}
void
link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
{
tfeedback_decl *tfeedback_decls = NULL;
unsigned num_tfeedback_decls = prog->TransformFeedback.NumVarying;
void *mem_ctx = ralloc_context(NULL); // temporary linker context
prog->LinkStatus = false;
prog->Validated = false;
prog->_Used = false;
ralloc_free(prog->InfoLog);
prog->InfoLog = ralloc_strdup(NULL, "");
ralloc_free(prog->UniformBlocks);
prog->UniformBlocks = NULL;
prog->NumUniformBlocks = 0;
for (int i = 0; i < MESA_SHADER_TYPES; i++) {
ralloc_free(prog->UniformBlockStageIndex[i]);
prog->UniformBlockStageIndex[i] = 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;
const bool is_es_prog =
(prog->NumShaders > 0 && prog->Shaders[0]->IsES) ? true : false;
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);
if (prog->Shaders[i]->IsES != is_es_prog) {
linker_error(prog, "all shaders must use same shading "
"language version\n");
goto done;
}
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.
*
* GLSL ES has never allowed mixing of shading language versions.
*/
if ((is_es_prog || max_version >= 130)
&& min_version != max_version) {
linker_error(prog, "all shaders must use same shading "
"language version\n");
goto done;
}
prog->Version = max_version;
prog->IsES = is_es_prog;
for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] != NULL)
ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
prog->_LinkedShaders[i] = NULL;
}
/* Link all shaders for a particular stage and validate the result.
*/
if (num_vert_shaders > 0) {
gl_shader *const sh =
link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
num_vert_shaders);
if (sh == NULL)
goto done;
if (!validate_vertex_shader_executable(prog, sh))
goto done;
_mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
sh);
}
if (num_frag_shaders > 0) {
gl_shader *const sh =
link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
num_frag_shaders);
if (sh == NULL)
goto done;
if (!validate_fragment_shader_executable(prog, sh))
goto done;
_mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
sh);
}
/* 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)) {
unsigned prev;
for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
if (prog->_LinkedShaders[prev] != NULL)
break;
}
/* Validate the inputs of each stage with the output of the preceding
* stage.
*/
for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] == NULL)
continue;
if (!validate_interstage_interface_blocks(prog->_LinkedShaders[prev],
prog->_LinkedShaders[i])) {
linker_error(prog, "interface block mismatch between shader stages\n");
goto done;
}
if (!cross_validate_outputs_to_inputs(prog,
prog->_LinkedShaders[prev],
prog->_LinkedShaders[i]))
goto done;
prev = i;
}
prog->LinkStatus = true;
}
for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] != NULL)
lower_named_interface_blocks(mem_ctx, prog->_LinkedShaders[i]);
}
/* Implement the GLSL 1.30+ rule for discard vs infinite loops Do
* it before optimization because we want most of the checks to get
* dropped thanks to constant propagation.
*
* This rule also applies to GLSL ES 3.00.
*/
if (max_version >= (is_es_prog ? 300 : 130)) {
struct gl_shader *sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
if (sh) {
lower_discard_flow(sh->ir);
}
}
if (!interstage_cross_validate_uniform_blocks(prog))
goto done;
/* 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 < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] == NULL)
continue;
detect_recursion_linked(prog, prog->_LinkedShaders[i]->ir);
if (!prog->LinkStatus)
goto done;
if (ctx->ShaderCompilerOptions[i].LowerClipDistance) {
lower_clip_distance(prog->_LinkedShaders[i]);
}
unsigned max_unroll = ctx->ShaderCompilerOptions[i].MaxUnrollIterations;
while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, false, max_unroll, &ctx->ShaderCompilerOptions[i]))
;
}
/* Mark all generic shader inputs and outputs as unpaired. */
if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
link_invalidate_variable_locations(
prog->_LinkedShaders[MESA_SHADER_VERTEX],
VERT_ATTRIB_GENERIC0, VARYING_SLOT_VAR0);
}
/* FINISHME: Geometry shaders not implemented yet */
if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {
link_invalidate_variable_locations(
prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
VARYING_SLOT_VAR0, FRAG_RESULT_DATA0);
}
/* 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_or_color_locations(prog, MESA_SHADER_VERTEX, 16)) {
goto done;
}
if (!assign_attribute_or_color_locations(prog, MESA_SHADER_FRAGMENT, MAX2(ctx->Const.MaxDrawBuffers, ctx->Const.MaxDualSourceDrawBuffers))) {
goto done;
}
unsigned first;
for (first = 0; first < MESA_SHADER_TYPES; first++) {
if (prog->_LinkedShaders[first] != NULL)
break;
}
if (num_tfeedback_decls != 0) {
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * the <count> specified by TransformFeedbackVaryingsEXT is
* non-zero, but the program object has no vertex or geometry
* shader;
*/
if (first >= MESA_SHADER_FRAGMENT) {
linker_error(prog, "Transform feedback varyings specified, but "
"no vertex or geometry shader is present.");
goto done;
}
tfeedback_decls = ralloc_array(mem_ctx, tfeedback_decl,
prog->TransformFeedback.NumVarying);
if (!parse_tfeedback_decls(ctx, prog, mem_ctx, num_tfeedback_decls,
prog->TransformFeedback.VaryingNames,
tfeedback_decls))
goto done;
}
/* Linking the stages in the opposite order (from fragment to vertex)
* ensures that inter-shader outputs written to in an earlier stage are
* eliminated if they are (transitively) not used in a later stage.
*/
int last, next;
for (last = MESA_SHADER_TYPES-1; last >= 0; last--) {
if (prog->_LinkedShaders[last] != NULL)
break;
}
if (last >= 0 && last < MESA_SHADER_FRAGMENT) {
gl_shader *const sh = prog->_LinkedShaders[last];
if (num_tfeedback_decls != 0) {
/* There was no fragment shader, but we still have to assign varying
* locations for use by transform feedback.
*/
if (!assign_varying_locations(ctx, mem_ctx, prog,
sh, NULL,
num_tfeedback_decls, tfeedback_decls))
goto done;
}
do_dead_builtin_varyings(ctx, sh, NULL,
num_tfeedback_decls, tfeedback_decls);
demote_shader_inputs_and_outputs(sh, ir_var_shader_out);
/* Eliminate code that is now dead due to unused outputs being demoted.
*/
while (do_dead_code(sh->ir, false))
;
}
else if (first == MESA_SHADER_FRAGMENT) {
/* If the program only contains a fragment shader...
*/
gl_shader *const sh = prog->_LinkedShaders[first];
do_dead_builtin_varyings(ctx, NULL, sh,
num_tfeedback_decls, tfeedback_decls);
demote_shader_inputs_and_outputs(sh, ir_var_shader_in);
while (do_dead_code(sh->ir, false))
;
}
next = last;
for (int i = next - 1; i >= 0; i--) {
if (prog->_LinkedShaders[i] == NULL)
continue;
gl_shader *const sh_i = prog->_LinkedShaders[i];
gl_shader *const sh_next = prog->_LinkedShaders[next];
if (!assign_varying_locations(ctx, mem_ctx, prog, sh_i, sh_next,
next == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0,
tfeedback_decls))
goto done;
do_dead_builtin_varyings(ctx, sh_i, sh_next,
next == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0,
tfeedback_decls);
demote_shader_inputs_and_outputs(sh_i, ir_var_shader_out);
demote_shader_inputs_and_outputs(sh_next, ir_var_shader_in);
/* Eliminate code that is now dead due to unused outputs being demoted.
*/
while (do_dead_code(sh_i->ir, false))
;
while (do_dead_code(sh_next->ir, false))
;
/* This must be done after all dead varyings are eliminated. */
if (!check_against_varying_limit(ctx, prog, sh_next))
goto done;
next = i;
}
if (!store_tfeedback_info(ctx, prog, num_tfeedback_decls, tfeedback_decls))
goto done;
update_array_sizes(prog);
link_assign_uniform_locations(prog);
store_fragdepth_layout(prog);
if (!check_resources(ctx, prog))
goto done;
/* OpenGL ES requires that a vertex shader and a fragment shader both be
* present in a linked program. By checking prog->IsES, we also
* catch the GL_ARB_ES2_compatibility case.
*/
if (!prog->InternalSeparateShader &&
(ctx->API == API_OPENGLES2 || prog->IsES)) {
if (prog->_LinkedShaders[MESA_SHADER_VERTEX] == NULL) {
linker_error(prog, "program lacks a vertex shader\n");
} else if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) {
linker_error(prog, "program lacks a fragment shader\n");
}
}
/* FINISHME: Assign fragment shader output locations. */
done:
free(vert_shader_list);
for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
if (prog->_LinkedShaders[i] == NULL)
continue;
/* Retain any live IR, but trash the rest. */
reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
/* The symbol table in the linked shaders may contain references to
* variables that were removed (e.g., unused uniforms). Since it may
* contain junk, there is no possible valid use. Delete it and set the
* pointer to NULL.
*/
delete prog->_LinkedShaders[i]->symbols;
prog->_LinkedShaders[i]->symbols = NULL;
}
ralloc_free(mem_ctx);
}