AuroraMiddleware/SPIRV-Cross-Vulnerable
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SPIRV-Cross-Vulnerable/spirv_cross.cpp

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/*
* Copyright 2015-2016 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "spirv_cross.hpp"
#include "GLSL.std.450.h"
#include "spirv_cfg.hpp"
#include <algorithm>
#include <cstring>
#include <utility>
using namespace std;
using namespace spv;
using namespace spirv_cross;
#define log(...) fprintf(stderr, __VA_ARGS__)
Instruction::Instruction(const vector<uint32_t> &spirv, uint32_t &index)
{
op = spirv[index] & 0xffff;
count = (spirv[index] >> 16) & 0xffff;
if (count == 0)
SPIRV_CROSS_THROW("SPIR-V instructions cannot consume 0 words. Invalid SPIR-V file.");
offset = index + 1;
length = count - 1;
index += count;
if (index > spirv.size())
SPIRV_CROSS_THROW("SPIR-V instruction goes out of bounds.");
}
Compiler::Compiler(vector<uint32_t> ir)
: spirv(move(ir))
{
parse();
}
string Compiler::compile()
{
return "";
}
bool Compiler::variable_storage_is_aliased(const SPIRVariable &v)
{
auto &type = get<SPIRType>(v.basetype);
bool ssbo = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBufferBlock)) != 0;
bool image = type.basetype == SPIRType::Image;
bool counter = type.basetype == SPIRType::AtomicCounter;
bool is_restrict = (meta[v.self].decoration.decoration_flags & (1ull << DecorationRestrict)) != 0;
return !is_restrict && (ssbo || image || counter);
}
bool Compiler::block_is_pure(const SPIRBlock &block)
{
for (auto &i : block.ops)
{
auto ops = stream(i);
auto op = static_cast<Op>(i.op);
switch (op)
{
case OpFunctionCall:
{
uint32_t func = ops[2];
if (!function_is_pure(get<SPIRFunction>(func)))
return false;
break;
}
case OpCopyMemory:
case OpStore:
{
auto &type = expression_type(ops[0]);
if (type.storage != StorageClassFunction)
return false;
break;
}
case OpImageWrite:
return false;
// Atomics are impure.
case OpAtomicLoad:
case OpAtomicStore:
case OpAtomicExchange:
case OpAtomicCompareExchange:
case OpAtomicIIncrement:
case OpAtomicIDecrement:
case OpAtomicIAdd:
case OpAtomicISub:
case OpAtomicSMin:
case OpAtomicUMin:
case OpAtomicSMax:
case OpAtomicUMax:
case OpAtomicAnd:
case OpAtomicOr:
case OpAtomicXor:
return false;
// Geometry shader builtins modify global state.
case OpEndPrimitive:
case OpEmitStreamVertex:
case OpEndStreamPrimitive:
case OpEmitVertex:
return false;
// Barriers disallow any reordering, so we should treat blocks with barrier as writing.
case OpControlBarrier:
case OpMemoryBarrier:
return false;
// OpExtInst is potentially impure depending on extension, but GLSL builtins are at least pure.
default:
break;
}
}
return true;
}
string Compiler::to_name(uint32_t id, bool allow_alias)
{
if (allow_alias && ids.at(id).get_type() == TypeType)
{
// If this type is a simple alias, emit the
// name of the original type instead.
// We don't want to override the meta alias
// as that can be overridden by the reflection APIs after parse.
auto &type = get<SPIRType>(id);
if (type.type_alias)
return to_name(type.type_alias);
}
if (meta[id].decoration.alias.empty())
return join("_", id);
else
return meta.at(id).decoration.alias;
}
bool Compiler::function_is_pure(const SPIRFunction &func)
{
for (auto block : func.blocks)
{
if (!block_is_pure(get<SPIRBlock>(block)))
{
//fprintf(stderr, "Function %s is impure!\n", to_name(func.self).c_str());
return false;
}
}
//fprintf(stderr, "Function %s is pure!\n", to_name(func.self).c_str());
return true;
}
void Compiler::register_global_read_dependencies(const SPIRBlock &block, uint32_t id)
{
for (auto &i : block.ops)
{
auto ops = stream(i);
auto op = static_cast<Op>(i.op);
switch (op)
{
case OpFunctionCall:
{
uint32_t func = ops[2];
register_global_read_dependencies(get<SPIRFunction>(func), id);
break;
}
case OpLoad:
case OpImageRead:
{
// If we're in a storage class which does not get invalidated, adding dependencies here is no big deal.
auto *var = maybe_get_backing_variable(ops[2]);
if (var && var->storage != StorageClassFunction)
{
auto &type = get<SPIRType>(var->basetype);
// InputTargets are immutable.
if (type.basetype != SPIRType::Image && type.image.dim != DimSubpassData)
var->dependees.push_back(id);
}
break;
}
default:
break;
}
}
}
void Compiler::register_global_read_dependencies(const SPIRFunction &func, uint32_t id)
{
for (auto block : func.blocks)
register_global_read_dependencies(get<SPIRBlock>(block), id);
}
SPIRVariable *Compiler::maybe_get_backing_variable(uint32_t chain)
{
auto *var = maybe_get<SPIRVariable>(chain);
if (!var)
{
auto *cexpr = maybe_get<SPIRExpression>(chain);
if (cexpr)
var = maybe_get<SPIRVariable>(cexpr->loaded_from);
}
return var;
}
void Compiler::register_read(uint32_t expr, uint32_t chain, bool forwarded)
{
auto &e = get<SPIRExpression>(expr);
auto *var = maybe_get_backing_variable(chain);
if (var)
{
e.loaded_from = var->self;
// If the backing variable is immutable, we do not need to depend on the variable.
if (forwarded && !is_immutable(var->self))
var->dependees.push_back(e.self);
// If we load from a parameter, make sure we create "inout" if we also write to the parameter.
// The default is "in" however, so we never invalidate our compilation by reading.
if (var && var->parameter)
var->parameter->read_count++;
}
}
void Compiler::register_write(uint32_t chain)
{
auto *var = maybe_get<SPIRVariable>(chain);
if (!var)
{
// If we're storing through an access chain, invalidate the backing variable instead.
auto *expr = maybe_get<SPIRExpression>(chain);
if (expr && expr->loaded_from)
var = maybe_get<SPIRVariable>(expr->loaded_from);
}
if (var)
{
// If our variable is in a storage class which can alias with other buffers,
// invalidate all variables which depend on aliased variables.
if (variable_storage_is_aliased(*var))
flush_all_aliased_variables();
else if (var)
flush_dependees(*var);
// We tried to write to a parameter which is not marked with out qualifier, force a recompile.
if (var->parameter && var->parameter->write_count == 0)
{
var->parameter->write_count++;
force_recompile = true;
}
}
}
void Compiler::flush_dependees(SPIRVariable &var)
{
for (auto expr : var.dependees)
invalid_expressions.insert(expr);
var.dependees.clear();
}
void Compiler::flush_all_aliased_variables()
{
for (auto aliased : aliased_variables)
flush_dependees(get<SPIRVariable>(aliased));
}
void Compiler::flush_all_atomic_capable_variables()
{
for (auto global : global_variables)
flush_dependees(get<SPIRVariable>(global));
flush_all_aliased_variables();
}
void Compiler::flush_all_active_variables()
{
// Invalidate all temporaries we read from variables in this block since they were forwarded.
// Invalidate all temporaries we read from globals.
for (auto &v : current_function->local_variables)
flush_dependees(get<SPIRVariable>(v));
for (auto &arg : current_function->arguments)
flush_dependees(get<SPIRVariable>(arg.id));
for (auto global : global_variables)
flush_dependees(get<SPIRVariable>(global));
flush_all_aliased_variables();
}
const SPIRType &Compiler::expression_type(uint32_t id) const
{
switch (ids[id].get_type())
{
case TypeVariable:
return get<SPIRType>(get<SPIRVariable>(id).basetype);
case TypeExpression:
return get<SPIRType>(get<SPIRExpression>(id).expression_type);
case TypeConstant:
return get<SPIRType>(get<SPIRConstant>(id).constant_type);
case TypeConstantOp:
return get<SPIRType>(get<SPIRConstantOp>(id).basetype);
case TypeUndef:
return get<SPIRType>(get<SPIRUndef>(id).basetype);
default:
SPIRV_CROSS_THROW("Cannot resolve expression type.");
}
}
bool Compiler::expression_is_lvalue(uint32_t id) const
{
auto &type = expression_type(id);
switch (type.basetype)
{
case SPIRType::SampledImage:
case SPIRType::Image:
case SPIRType::Sampler:
return false;
default:
return true;
}
}
bool Compiler::is_immutable(uint32_t id) const
{
if (ids[id].get_type() == TypeVariable)
{
auto &var = get<SPIRVariable>(id);
// Anything we load from the UniformConstant address space is guaranteed to be immutable.
bool pointer_to_const = var.storage == StorageClassUniformConstant;
return pointer_to_const || var.phi_variable || !expression_is_lvalue(id);
}
else if (ids[id].get_type() == TypeExpression)
return get<SPIRExpression>(id).immutable;
else if (ids[id].get_type() == TypeConstant || ids[id].get_type() == TypeConstantOp ||
ids[id].get_type() == TypeUndef)
return true;
else
return false;
}
static inline bool storage_class_is_interface(spv::StorageClass storage)
{
switch (storage)
{
case StorageClassInput:
case StorageClassOutput:
case StorageClassUniform:
case StorageClassUniformConstant:
case StorageClassAtomicCounter:
case StorageClassPushConstant:
return true;
default:
return false;
}
}
bool Compiler::is_hidden_variable(const SPIRVariable &var, bool include_builtins) const
{
if ((is_builtin_variable(var) && !include_builtins) || var.remapped_variable)
return true;
// Combined image samplers are always considered active as they are "magic" variables.
if (find_if(begin(combined_image_samplers), end(combined_image_samplers), [&var](const CombinedImageSampler &samp) {
return samp.combined_id == var.self;
}) != end(combined_image_samplers))
{
return false;
}
bool hidden = false;
if (check_active_interface_variables && storage_class_is_interface(var.storage))
hidden = active_interface_variables.find(var.self) == end(active_interface_variables);
return hidden;
}
bool Compiler::is_builtin_variable(const SPIRVariable &var) const
{
if (var.compat_builtin || meta[var.self].decoration.builtin)
return true;
// We can have builtin structs as well. If one member of a struct is builtin, the struct must also be builtin.
for (auto &m : meta[get<SPIRType>(var.basetype).self].members)
if (m.builtin)
return true;
return false;
}
bool Compiler::is_member_builtin(const SPIRType &type, uint32_t index, BuiltIn *builtin) const
{
auto &memb = meta[type.self].members;
if (index < memb.size() && memb[index].builtin)
{
if (builtin)
*builtin = memb[index].builtin_type;
return true;
}
return false;
}
bool Compiler::is_scalar(const SPIRType &type) const
{
return type.vecsize == 1 && type.columns == 1;
}
bool Compiler::is_vector(const SPIRType &type) const
{
return type.vecsize > 1 && type.columns == 1;
}
bool Compiler::is_matrix(const SPIRType &type) const
{
return type.vecsize > 1 && type.columns > 1;
}
ShaderResources Compiler::get_shader_resources() const
{
return get_shader_resources(nullptr);
}
ShaderResources Compiler::get_shader_resources(const unordered_set<uint32_t> &active_variables) const
{
return get_shader_resources(&active_variables);
}
bool Compiler::InterfaceVariableAccessHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
uint32_t variable = 0;
switch (opcode)
{
// Need this first, otherwise, GCC complains about unhandled switch statements.
default:
break;
case OpFunctionCall:
{
// Invalid SPIR-V.
if (length < 3)
return false;
uint32_t count = length - 3;
args += 3;
for (uint32_t i = 0; i < count; i++)
{
auto *var = compiler.maybe_get<SPIRVariable>(args[i]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[i]);
}
break;
}
case OpAtomicStore:
case OpStore:
// Invalid SPIR-V.
if (length < 1)
return false;
variable = args[0];
break;
case OpCopyMemory:
{
if (length < 3)
return false;
auto *var = compiler.maybe_get<SPIRVariable>(args[0]);
if (var && storage_class_is_interface(var->storage))
variables.insert(variable);
var = compiler.maybe_get<SPIRVariable>(args[1]);
if (var && storage_class_is_interface(var->storage))
variables.insert(variable);
break;
}
case OpAccessChain:
case OpInBoundsAccessChain:
case OpLoad:
case OpCopyObject:
case OpImageTexelPointer:
case OpAtomicLoad:
case OpAtomicExchange:
case OpAtomicCompareExchange:
case OpAtomicIIncrement:
case OpAtomicIDecrement:
case OpAtomicIAdd:
case OpAtomicISub:
case OpAtomicSMin:
case OpAtomicUMin:
case OpAtomicSMax:
case OpAtomicUMax:
case OpAtomicAnd:
case OpAtomicOr:
case OpAtomicXor:
// Invalid SPIR-V.
if (length < 3)
return false;
variable = args[2];
break;
}
if (variable)
{
auto *var = compiler.maybe_get<SPIRVariable>(variable);
if (var && storage_class_is_interface(var->storage))
variables.insert(variable);
}
return true;
}
unordered_set<uint32_t> Compiler::get_active_interface_variables() const
{
// Traverse the call graph and find all interface variables which are in use.
unordered_set<uint32_t> variables;
InterfaceVariableAccessHandler handler(*this, variables);
traverse_all_reachable_opcodes(get<SPIRFunction>(entry_point), handler);
return variables;
}
void Compiler::set_enabled_interface_variables(std::unordered_set<uint32_t> active_variables)
{
active_interface_variables = move(active_variables);
check_active_interface_variables = true;
}
ShaderResources Compiler::get_shader_resources(const unordered_set<uint32_t> *active_variables) const
{
ShaderResources res;
for (auto &id : ids)
{
if (id.get_type() != TypeVariable)
continue;
auto &var = id.get<SPIRVariable>();
auto &type = get<SPIRType>(var.basetype);
// It is possible for uniform storage classes to be passed as function parameters, so detect
// that. To detect function parameters, check of StorageClass of variable is function scope.
if (var.storage == StorageClassFunction || !type.pointer || is_builtin_variable(var))
continue;
if (active_variables && active_variables->find(var.self) == end(*active_variables))
continue;
// Input
if (var.storage == StorageClassInput && interface_variable_exists_in_entry_point(var.self))
{
if (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock))
res.stage_inputs.push_back({ var.self, var.basetype, type.self, meta[type.self].decoration.alias });
else
res.stage_inputs.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Subpass inputs
else if (var.storage == StorageClassUniformConstant && type.image.dim == DimSubpassData)
{
res.subpass_inputs.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Outputs
else if (var.storage == StorageClassOutput && interface_variable_exists_in_entry_point(var.self))
{
if (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock))
res.stage_outputs.push_back({ var.self, var.basetype, type.self, meta[type.self].decoration.alias });
else
res.stage_outputs.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// UBOs
else if (type.storage == StorageClassUniform &&
(meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)))
{
res.uniform_buffers.push_back({ var.self, var.basetype, type.self, meta[type.self].decoration.alias });
}
// SSBOs
else if (type.storage == StorageClassUniform &&
(meta[type.self].decoration.decoration_flags & (1ull << DecorationBufferBlock)))
{
res.storage_buffers.push_back({ var.self, var.basetype, type.self, meta[type.self].decoration.alias });
}
// Push constant blocks
else if (type.storage == StorageClassPushConstant)
{
// There can only be one push constant block, but keep the vector in case this restriction is lifted
// in the future.
res.push_constant_buffers.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Images
else if (type.storage == StorageClassUniformConstant && type.basetype == SPIRType::Image &&
type.image.sampled == 2)
{
res.storage_images.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Separate images
else if (type.storage == StorageClassUniformConstant && type.basetype == SPIRType::Image &&
type.image.sampled == 1)
{
res.separate_images.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Separate samplers
else if (type.storage == StorageClassUniformConstant && type.basetype == SPIRType::Sampler)
{
res.separate_samplers.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Textures
else if (type.storage == StorageClassUniformConstant && type.basetype == SPIRType::SampledImage)
{
res.sampled_images.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
// Atomic counters
else if (type.storage == StorageClassAtomicCounter)
{
res.atomic_counters.push_back({ var.self, var.basetype, type.self, meta[var.self].decoration.alias });
}
}
return res;
}
static inline uint32_t swap_endian(uint32_t v)
{
return ((v >> 24) & 0x000000ffu) | ((v >> 8) & 0x0000ff00u) | ((v << 8) & 0x00ff0000u) | ((v << 24) & 0xff000000u);
}
static string extract_string(const vector<uint32_t> &spirv, uint32_t offset)
{
string ret;
for (uint32_t i = offset; i < spirv.size(); i++)
{
uint32_t w = spirv[i];
for (uint32_t j = 0; j < 4; j++, w >>= 8)
{
char c = w & 0xff;
if (c == '\0')
return ret;
ret += c;
}
}
SPIRV_CROSS_THROW("String was not terminated before EOF");
}
static bool is_valid_spirv_version(uint32_t version)
{
switch (version)
{
// Allow v99 since it tends to just work.
case 99:
case 0x10000: // SPIR-V 1.0
case 0x10100: // SPIR-V 1.1
return true;
default:
return false;
}
}
void Compiler::parse()
{
auto len = spirv.size();
if (len < 5)
SPIRV_CROSS_THROW("SPIRV file too small.");
auto s = spirv.data();
// Endian-swap if we need to.
if (s[0] == swap_endian(MagicNumber))
transform(begin(spirv), end(spirv), begin(spirv), [](uint32_t c) { return swap_endian(c); });
if (s[0] != MagicNumber || !is_valid_spirv_version(s[1]))
SPIRV_CROSS_THROW("Invalid SPIRV format.");
uint32_t bound = s[3];
ids.resize(bound);
meta.resize(bound);
uint32_t offset = 5;
while (offset < len)
inst.emplace_back(spirv, offset);
for (auto &i : inst)
parse(i);
if (current_function)
SPIRV_CROSS_THROW("Function was not terminated.");
if (current_block)
SPIRV_CROSS_THROW("Block was not terminated.");
}
void Compiler::flatten_interface_block(uint32_t id)
{
auto &var = get<SPIRVariable>(id);
auto &type = get<SPIRType>(var.basetype);
auto flags = meta.at(type.self).decoration.decoration_flags;
if (!type.array.empty())
SPIRV_CROSS_THROW("Type is array of UBOs.");
if (type.basetype != SPIRType::Struct)
SPIRV_CROSS_THROW("Type is not a struct.");
if ((flags & (1ull << DecorationBlock)) == 0)
SPIRV_CROSS_THROW("Type is not a block.");
if (type.member_types.empty())
SPIRV_CROSS_THROW("Member list of struct is empty.");
uint32_t t = type.member_types[0];
for (auto &m : type.member_types)
if (t != m)
SPIRV_CROSS_THROW("Types in block differ.");
auto &mtype = get<SPIRType>(t);
if (!mtype.array.empty())
SPIRV_CROSS_THROW("Member type cannot be arrays.");
if (mtype.basetype == SPIRType::Struct)
SPIRV_CROSS_THROW("Member type cannot be struct.");
// Inherit variable name from interface block name.
meta.at(var.self).decoration.alias = meta.at(type.self).decoration.alias;
auto storage = var.storage;
if (storage == StorageClassUniform)
storage = StorageClassUniformConstant;
// Change type definition in-place into an array instead.
// Access chains will still work as-is.
uint32_t array_size = uint32_t(type.member_types.size());
type = mtype;
type.array.push_back(array_size);
type.pointer = true;
type.storage = storage;
var.storage = storage;
}
void Compiler::update_name_cache(unordered_set<string> &cache, string &name)
{
if (name.empty())
return;
if (cache.find(name) == end(cache))
{
cache.insert(name);
return;
}
uint32_t counter = 0;
auto tmpname = name;
// If there is a collision (very rare),
// keep tacking on extra identifier until it's unique.
do
{
counter++;
name = tmpname + "_" + convert_to_string(counter);
} while (cache.find(name) != end(cache));
cache.insert(name);
}
void Compiler::set_name(uint32_t id, const std::string &name)
{
auto &str = meta.at(id).decoration.alias;
str.clear();
if (name.empty())
return;
// Reserved for temporaries.
if (name[0] == '_' && name.size() >= 2 && isdigit(name[1]))
return;
// Functions in glslangValidator are mangled with name(<mangled> stuff.
// Normally, we would never see '(' in any legal indentifiers, so just strip them out.
str = name.substr(0, name.find('('));
for (uint32_t i = 0; i < str.size(); i++)
{
auto &c = str[i];
// _<num> variables are reserved by the internal implementation,
// otherwise, make sure the name is a valid identifier.
if (i == 0 || (str[0] == '_' && i == 1))
c = isalpha(c) ? c : '_';
else
c = isalnum(c) ? c : '_';
}
}
const SPIRType &Compiler::get_type(uint32_t id) const
{
return get<SPIRType>(id);
}
void Compiler::set_member_decoration(uint32_t id, uint32_t index, Decoration decoration, uint32_t argument)
{
meta.at(id).members.resize(max(meta[id].members.size(), size_t(index) + 1));
auto &dec = meta.at(id).members[index];
dec.decoration_flags |= 1ull << decoration;
switch (decoration)
{
case DecorationBuiltIn:
dec.builtin = true;
dec.builtin_type = static_cast<BuiltIn>(argument);
break;
case DecorationLocation:
dec.location = argument;
break;
case DecorationOffset:
dec.offset = argument;
break;
case DecorationSpecId:
dec.spec_id = argument;
break;
default:
break;
}
}
void Compiler::set_member_name(uint32_t id, uint32_t index, const std::string &name)
{
meta.at(id).members.resize(max(meta[id].members.size(), size_t(index) + 1));
meta.at(id).members[index].alias = name;
}
const std::string &Compiler::get_member_name(uint32_t id, uint32_t index) const
{
auto &m = meta.at(id);
if (index >= m.members.size())
{
static string empty;
return empty;
}
return m.members[index].alias;
}
void Compiler::set_member_qualified_name(uint32_t id, uint32_t index, const std::string &name)
{
meta.at(id).members.resize(max(meta[id].members.size(), size_t(index) + 1));
meta.at(id).members[index].qualified_alias = name;
}
uint32_t Compiler::get_member_decoration(uint32_t id, uint32_t index, Decoration decoration) const
{
auto &m = meta.at(id);
if (index >= m.members.size())
return 0;
auto &dec = m.members[index];
if (!(dec.decoration_flags & (1ull << decoration)))
return 0;
switch (decoration)
{
case DecorationBuiltIn:
return dec.builtin_type;
case DecorationLocation:
return dec.location;
case DecorationOffset:
return dec.offset;
case DecorationSpecId:
return dec.spec_id;
default:
return 0;
}
}
uint64_t Compiler::get_member_decoration_mask(uint32_t id, uint32_t index) const
{
auto &m = meta.at(id);
if (index >= m.members.size())
return 0;
return m.members[index].decoration_flags;
}
void Compiler::unset_member_decoration(uint32_t id, uint32_t index, Decoration decoration)
{
auto &m = meta.at(id);
if (index >= m.members.size())
return;
auto &dec = m.members[index];
dec.decoration_flags &= ~(1ull << decoration);
switch (decoration)
{
case DecorationBuiltIn:
dec.builtin = false;
break;
case DecorationLocation:
dec.location = 0;
break;
case DecorationOffset:
dec.offset = 0;
break;
case DecorationSpecId:
dec.spec_id = 0;
break;
default:
break;
}
}
void Compiler::set_decoration(uint32_t id, Decoration decoration, uint32_t argument)
{
auto &dec = meta.at(id).decoration;
dec.decoration_flags |= 1ull << decoration;
switch (decoration)
{
case DecorationBuiltIn:
dec.builtin = true;
dec.builtin_type = static_cast<BuiltIn>(argument);
break;
case DecorationLocation:
dec.location = argument;
break;
case DecorationOffset:
dec.offset = argument;
break;
case DecorationArrayStride:
dec.array_stride = argument;
break;
case DecorationBinding:
dec.binding = argument;
break;
case DecorationDescriptorSet:
dec.set = argument;
break;
case DecorationInputAttachmentIndex:
dec.input_attachment = argument;
break;
case DecorationSpecId:
dec.spec_id = argument;
break;
default:
break;
}
}
StorageClass Compiler::get_storage_class(uint32_t id) const
{
return get<SPIRVariable>(id).storage;
}
const std::string &Compiler::get_name(uint32_t id) const
{
return meta.at(id).decoration.alias;
}
uint64_t Compiler::get_decoration_mask(uint32_t id) const
{
auto &dec = meta.at(id).decoration;
return dec.decoration_flags;
}
uint32_t Compiler::get_decoration(uint32_t id, Decoration decoration) const
{
auto &dec = meta.at(id).decoration;
if (!(dec.decoration_flags & (1ull << decoration)))
return 0;
switch (decoration)
{
case DecorationBuiltIn:
return dec.builtin_type;
case DecorationLocation:
return dec.location;
case DecorationOffset:
return dec.offset;
case DecorationBinding:
return dec.binding;
case DecorationDescriptorSet:
return dec.set;
case DecorationInputAttachmentIndex:
return dec.input_attachment;
case DecorationSpecId:
return dec.spec_id;
case DecorationNonWritable:
case DecorationNonReadable:
return 1;
default:
return 0;
}
}
void Compiler::unset_decoration(uint32_t id, Decoration decoration)
{
auto &dec = meta.at(id).decoration;
dec.decoration_flags &= ~(1ull << decoration);
switch (decoration)
{
case DecorationBuiltIn:
dec.builtin = false;
break;
case DecorationLocation:
dec.location = 0;
break;
case DecorationOffset:
dec.offset = 0;
break;
case DecorationBinding:
dec.binding = 0;
break;
case DecorationDescriptorSet:
dec.set = 0;
break;
case DecorationInputAttachmentIndex:
dec.input_attachment = 0;
break;
case DecorationSpecId:
dec.spec_id = 0;
break;
default:
break;
}
}
void Compiler::parse(const Instruction &instruction)
{
auto ops = stream(instruction);
auto op = static_cast<Op>(instruction.op);
uint32_t length = instruction.length;
switch (op)
{
case OpMemoryModel:
case OpSourceExtension:
case OpNop:
case OpLine:
break;
case OpSource:
{
auto lang = static_cast<SourceLanguage>(ops[0]);
switch (lang)
{
case SourceLanguageESSL:
source.es = true;
source.version = ops[1];
source.known = true;
break;
case SourceLanguageGLSL:
source.es = false;
source.version = ops[1];
source.known = true;
break;
default:
source.known = false;
break;
}
break;
}
case OpUndef:
{
uint32_t result_type = ops[0];
uint32_t id = ops[1];
set<SPIRUndef>(id, result_type);
break;
}
case OpCapability:
{
uint32_t cap = ops[0];
if (cap == CapabilityKernel)
SPIRV_CROSS_THROW("Kernel capability not supported.");
break;
}
case OpExtInstImport:
{
uint32_t id = ops[0];
auto ext = extract_string(spirv, instruction.offset + 1);
if (ext == "GLSL.std.450")
set<SPIRExtension>(id, SPIRExtension::GLSL);
else
SPIRV_CROSS_THROW("Only GLSL.std.450 extension interface supported.");
break;
}
case OpEntryPoint:
{
auto itr =
entry_points.insert(make_pair(ops[1], SPIREntryPoint(ops[1], static_cast<ExecutionModel>(ops[0]),
extract_string(spirv, instruction.offset + 2))));
auto &e = itr.first->second;
// Strings need nul-terminator and consume the whole word.
uint32_t strlen_words = uint32_t((e.name.size() + 1 + 3) >> 2);
e.interface_variables.insert(end(e.interface_variables), ops + strlen_words + 2, ops + instruction.length);
// Set the name of the entry point in case OpName is not provided later
set_name(ops[1], e.name);
// If we don't have an entry, make the first one our "default".
if (!entry_point)
entry_point = ops[1];
break;
}
case OpExecutionMode:
{
auto &execution = entry_points[ops[0]];
auto mode = static_cast<ExecutionMode>(ops[1]);
execution.flags |= 1ull << mode;
switch (mode)
{
case ExecutionModeInvocations:
execution.invocations = ops[2];
break;
case ExecutionModeLocalSize:
execution.workgroup_size.x = ops[2];
execution.workgroup_size.y = ops[3];
execution.workgroup_size.z = ops[4];
break;
case ExecutionModeOutputVertices:
execution.output_vertices = ops[2];
break;
default:
break;
}
break;
}
case OpName:
{
uint32_t id = ops[0];
set_name(id, extract_string(spirv, instruction.offset + 1));
break;
}
case OpMemberName:
{
uint32_t id = ops[0];
uint32_t member = ops[1];
set_member_name(id, member, extract_string(spirv, instruction.offset + 2));
break;
}
case OpDecorate:
{
uint32_t id = ops[0];
auto decoration = static_cast<Decoration>(ops[1]);
if (length >= 3)
set_decoration(id, decoration, ops[2]);
else
set_decoration(id, decoration);
break;
}
case OpMemberDecorate:
{
uint32_t id = ops[0];
uint32_t member = ops[1];
auto decoration = static_cast<Decoration>(ops[2]);
if (length >= 4)
set_member_decoration(id, member, decoration, ops[3]);
else
set_member_decoration(id, member, decoration);
break;
}
// Build up basic types.
case OpTypeVoid:
{
uint32_t id = ops[0];
auto &type = set<SPIRType>(id);
type.basetype = SPIRType::Void;
break;
}
case OpTypeBool:
{
uint32_t id = ops[0];
auto &type = set<SPIRType>(id);
type.basetype = SPIRType::Boolean;
type.width = 1;
break;
}
case OpTypeFloat:
{
uint32_t id = ops[0];
uint32_t width = ops[1];
auto &type = set<SPIRType>(id);
type.basetype = width > 32 ? SPIRType::Double : SPIRType::Float;
type.width = width;
break;
}
case OpTypeInt:
{
uint32_t id = ops[0];
uint32_t width = ops[1];
auto &type = set<SPIRType>(id);
type.basetype =
ops[2] ? (width > 32 ? SPIRType::Int64 : SPIRType::Int) : (width > 32 ? SPIRType::UInt64 : SPIRType::UInt);
type.width = width;
break;
}
// Build composite types by "inheriting".
// NOTE: The self member is also copied! For pointers and array modifiers this is a good thing
// since we can refer to decorations on pointee classes which is needed for UBO/SSBO, I/O blocks in geometry/tess etc.
case OpTypeVector:
{
uint32_t id = ops[0];
uint32_t vecsize = ops[2];
auto &base = get<SPIRType>(ops[1]);
auto &vecbase = set<SPIRType>(id);
vecbase = base;
vecbase.vecsize = vecsize;
vecbase.self = id;
break;
}
case OpTypeMatrix:
{
uint32_t id = ops[0];
uint32_t colcount = ops[2];
auto &base = get<SPIRType>(ops[1]);
auto &matrixbase = set<SPIRType>(id);
matrixbase = base;
matrixbase.columns = colcount;
matrixbase.self = id;
break;
}
case OpTypeArray:
{
uint32_t id = ops[0];
auto &base = get<SPIRType>(ops[1]);
auto &arraybase = set<SPIRType>(id);
arraybase = base;
auto *c = maybe_get<SPIRConstant>(ops[2]);
bool literal = c && !c->specialization;
arraybase.array_size_literal.push_back(literal);
arraybase.array.push_back(literal ? c->scalar() : ops[2]);
// Do NOT set arraybase.self!
break;
}
case OpTypeRuntimeArray:
{
uint32_t id = ops[0];
auto &base = get<SPIRType>(ops[1]);
auto &arraybase = set<SPIRType>(id);
arraybase = base;
arraybase.array.push_back(0);
arraybase.array_size_literal.push_back(true);
// Do NOT set arraybase.self!
break;
}
case OpTypeImage:
{
uint32_t id = ops[0];
auto &type = set<SPIRType>(id);
type.basetype = SPIRType::Image;
type.image.type = ops[1];
type.image.dim = static_cast<Dim>(ops[2]);
type.image.depth = ops[3] != 0;
type.image.arrayed = ops[4] != 0;
type.image.ms = ops[5] != 0;
type.image.sampled = ops[6];
type.image.format = static_cast<ImageFormat>(ops[7]);
break;
}
case OpTypeSampledImage:
{
uint32_t id = ops[0];
uint32_t imagetype = ops[1];
auto &type = set<SPIRType>(id);
type = get<SPIRType>(imagetype);
type.basetype = SPIRType::SampledImage;
type.self = id;
break;
}
// Not really used.
case OpTypeSampler:
{
uint32_t id = ops[0];
auto &type = set<SPIRType>(id);
type.basetype = SPIRType::Sampler;
break;
}
case OpTypePointer:
{
uint32_t id = ops[0];
auto &base = get<SPIRType>(ops[2]);
auto &ptrbase = set<SPIRType>(id);
ptrbase = base;
if (ptrbase.pointer)
SPIRV_CROSS_THROW("Cannot make pointer-to-pointer type.");
ptrbase.pointer = true;
ptrbase.storage = static_cast<StorageClass>(ops[1]);
if (ptrbase.storage == StorageClassAtomicCounter)
ptrbase.basetype = SPIRType::AtomicCounter;
// Do NOT set ptrbase.self!
break;
}
case OpTypeStruct:
{
uint32_t id = ops[0];
auto &type = set<SPIRType>(id);
type.basetype = SPIRType::Struct;
for (uint32_t i = 1; i < length; i++)
type.member_types.push_back(ops[i]);
// Check if we have seen this struct type before, with just different
// decorations.
//
// Add workaround for issue #17 as well by looking at OpName for the struct
// types, which we shouldn't normally do.
// We should not normally have to consider type aliases like this to begin with
// however ... glslang issues #304, #307 cover this.
for (auto &other : global_struct_cache)
{
if (get_name(type.self) == get_name(other) && types_are_logically_equivalent(type, get<SPIRType>(other)))
{
type.type_alias = other;
break;
}
}
if (type.type_alias == 0)
global_struct_cache.push_back(id);
break;
}
case OpTypeFunction:
{
uint32_t id = ops[0];
uint32_t ret = ops[1];
auto &func = set<SPIRFunctionPrototype>(id, ret);
for (uint32_t i = 2; i < length; i++)
func.parameter_types.push_back(ops[i]);
break;
}
// Variable declaration
// All variables are essentially pointers with a storage qualifier.
case OpVariable:
{
uint32_t type = ops[0];
uint32_t id = ops[1];
auto storage = static_cast<StorageClass>(ops[2]);
uint32_t initializer = length == 4 ? ops[3] : 0;
if (storage == StorageClassFunction)
{
if (!current_function)
SPIRV_CROSS_THROW("No function currently in scope");
current_function->add_local_variable(id);
}
else if (storage == StorageClassPrivate || storage == StorageClassWorkgroup || storage == StorageClassOutput)
{
global_variables.push_back(id);
}
auto &var = set<SPIRVariable>(id, type, storage, initializer);
if (variable_storage_is_aliased(var))
aliased_variables.push_back(var.self);
// glslangValidator does not emit required qualifiers here.
// Solve this by making the image access as restricted as possible
// and loosen up if we need to.
auto &vartype = expression_type(id);
if (vartype.basetype == SPIRType::Image)
{
auto &flags = meta.at(id).decoration.decoration_flags;
flags |= 1ull << DecorationNonWritable;
flags |= 1ull << DecorationNonReadable;
}
break;
}
// OpPhi
// OpPhi is a fairly magical opcode.
// It selects temporary variables based on which parent block we *came from*.
// In high-level languages we can "de-SSA" by creating a function local, and flush out temporaries to this function-local
// variable to emulate SSA Phi.
case OpPhi:
{
if (!current_function)
SPIRV_CROSS_THROW("No function currently in scope");
if (!current_block)
SPIRV_CROSS_THROW("No block currently in scope");
uint32_t result_type = ops[0];
uint32_t id = ops[1];
// Instead of a temporary, create a new function-wide temporary with this ID instead.
auto &var = set<SPIRVariable>(id, result_type, spv::StorageClassFunction);
var.phi_variable = true;
current_function->add_local_variable(id);
for (uint32_t i = 2; i + 2 <= length; i += 2)
current_block->phi_variables.push_back({ ops[i], ops[i + 1], id });
break;
}
// Constants
case OpSpecConstant:
case OpConstant:
{
uint32_t id = ops[1];
auto &type = get<SPIRType>(ops[0]);
if (type.width > 32)
set<SPIRConstant>(id, ops[0], ops[2] | (uint64_t(ops[3]) << 32)).specialization = op == OpSpecConstant;
else
set<SPIRConstant>(id, ops[0], ops[2]).specialization = op == OpSpecConstant;
break;
}
case OpSpecConstantFalse:
case OpConstantFalse:
{
uint32_t id = ops[1];
set<SPIRConstant>(id, ops[0], uint32_t(0)).specialization = op == OpSpecConstantFalse;
break;
}
case OpSpecConstantTrue:
case OpConstantTrue:
{
uint32_t id = ops[1];
set<SPIRConstant>(id, ops[0], uint32_t(1)).specialization = op == OpSpecConstantTrue;
break;
}
case OpSpecConstantComposite:
case OpConstantComposite:
{
uint32_t id = ops[1];
uint32_t type = ops[0];
auto &ctype = get<SPIRType>(type);
SPIRConstant *constant = nullptr;
// We can have constants which are structs and arrays.
// In this case, our SPIRConstant will be a list of other SPIRConstant ids which we
// can refer to.
if (ctype.basetype == SPIRType::Struct || !ctype.array.empty())
{
constant = &set<SPIRConstant>(id, type, ops + 2, length - 2);
constant->specialization = op == OpSpecConstantComposite;
break;
}
bool type_64bit = ctype.width > 32;
bool matrix = ctype.columns > 1;
if (matrix)
{
switch (length - 2)
{
case 1:
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).vector());
break;
case 2:
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).vector(),
get<SPIRConstant>(ops[3]).vector());
break;
case 3:
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).vector(),
get<SPIRConstant>(ops[3]).vector(), get<SPIRConstant>(ops[4]).vector());
break;
case 4:
constant =
&set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).vector(), get<SPIRConstant>(ops[3]).vector(),
get<SPIRConstant>(ops[4]).vector(), get<SPIRConstant>(ops[5]).vector());
break;
default:
SPIRV_CROSS_THROW("OpConstantComposite only supports 1, 2, 3 and 4 columns.");
}
}
else
{
switch (length - 2)
{
case 1:
if (type_64bit)
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar_u64());
else
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar());
break;
case 2:
if (type_64bit)
{
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar_u64(),
get<SPIRConstant>(ops[3]).scalar_u64());
}
else
{
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar(),
get<SPIRConstant>(ops[3]).scalar());
}
break;
case 3:
if (type_64bit)
{
constant = &set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar_u64(),
get<SPIRConstant>(ops[3]).scalar_u64(),
get<SPIRConstant>(ops[4]).scalar_u64());
}
else
{
constant =
&set<SPIRConstant>(id, type, get<SPIRConstant>(ops[2]).scalar(),
get<SPIRConstant>(ops[3]).scalar(), get<SPIRConstant>(ops[4]).scalar());
}
break;
case 4:
if (type_64bit)
{
constant = &set<SPIRConstant>(
id, type, get<SPIRConstant>(ops[2]).scalar_u64(), get<SPIRConstant>(ops[3]).scalar_u64(),
get<SPIRConstant>(ops[4]).scalar_u64(), get<SPIRConstant>(ops[5]).scalar_u64());
}
else
{
constant = &set<SPIRConstant>(
id, type, get<SPIRConstant>(ops[2]).scalar(), get<SPIRConstant>(ops[3]).scalar(),
get<SPIRConstant>(ops[4]).scalar(), get<SPIRConstant>(ops[5]).scalar());
}
break;
default:
SPIRV_CROSS_THROW("OpConstantComposite only supports 1, 2, 3 and 4 components.");
}
}
constant->specialization = op == OpSpecConstantComposite;
break;
}
// Functions
case OpFunction:
{
uint32_t res = ops[0];
uint32_t id = ops[1];
// Control
uint32_t type = ops[3];
if (current_function)
SPIRV_CROSS_THROW("Must end a function before starting a new one!");
current_function = &set<SPIRFunction>(id, res, type);
break;
}
case OpFunctionParameter:
{
uint32_t type = ops[0];
uint32_t id = ops[1];
if (!current_function)
SPIRV_CROSS_THROW("Must be in a function!");
current_function->add_parameter(type, id);
set<SPIRVariable>(id, type, StorageClassFunction);
break;
}
case OpFunctionEnd:
{
if (current_block)
{
// Very specific error message, but seems to come up quite often.
SPIRV_CROSS_THROW(
"Cannot end a function before ending the current block.\n"
"Likely cause: If this SPIR-V was created from glslang HLSL, make sure the entry point is valid.");
}
current_function = nullptr;
break;
}
// Blocks
case OpLabel:
{
// OpLabel always starts a block.
if (!current_function)
SPIRV_CROSS_THROW("Blocks cannot exist outside functions!");
uint32_t id = ops[0];
current_function->blocks.push_back(id);
if (!current_function->entry_block)
current_function->entry_block = id;
if (current_block)
SPIRV_CROSS_THROW("Cannot start a block before ending the current block.");
current_block = &set<SPIRBlock>(id);
break;
}
// Branch instructions end blocks.
case OpBranch:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
uint32_t target = ops[0];
current_block->terminator = SPIRBlock::Direct;
current_block->next_block = target;
current_block = nullptr;
break;
}
case OpBranchConditional:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
current_block->condition = ops[0];
current_block->true_block = ops[1];
current_block->false_block = ops[2];
current_block->terminator = SPIRBlock::Select;
current_block = nullptr;
break;
}
case OpSwitch:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
if (current_block->merge == SPIRBlock::MergeNone)
SPIRV_CROSS_THROW("Switch statement is not structured");
current_block->terminator = SPIRBlock::MultiSelect;
current_block->condition = ops[0];
current_block->default_block = ops[1];
for (uint32_t i = 2; i + 2 <= length; i += 2)
current_block->cases.push_back({ ops[i], ops[i + 1] });
// If we jump to next block, make it break instead since we're inside a switch case block at that point.
multiselect_merge_targets.insert(current_block->next_block);
current_block = nullptr;
break;
}
case OpKill:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
current_block->terminator = SPIRBlock::Kill;
current_block = nullptr;
break;
}
case OpReturn:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
current_block->terminator = SPIRBlock::Return;
current_block = nullptr;
break;
}
case OpReturnValue:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
current_block->terminator = SPIRBlock::Return;
current_block->return_value = ops[0];
current_block = nullptr;
break;
}
case OpUnreachable:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to end a non-existing block.");
current_block->terminator = SPIRBlock::Unreachable;
current_block = nullptr;
break;
}
case OpSelectionMerge:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to modify a non-existing block.");
current_block->next_block = ops[0];
current_block->merge = SPIRBlock::MergeSelection;
selection_merge_targets.insert(current_block->next_block);
break;
}
case OpLoopMerge:
{
if (!current_block)
SPIRV_CROSS_THROW("Trying to modify a non-existing block.");
current_block->merge_block = ops[0];
current_block->continue_block = ops[1];
current_block->merge = SPIRBlock::MergeLoop;
loop_blocks.insert(current_block->self);
loop_merge_targets.insert(current_block->merge_block);
// Don't add loop headers to continue blocks,
// which would make it impossible branch into the loop header since
// they are treated as continues.
if (current_block->continue_block != current_block->self)
continue_blocks.insert(current_block->continue_block);
break;
}
case OpSpecConstantOp:
{
if (length < 3)
SPIRV_CROSS_THROW("OpSpecConstantOp not enough arguments.");
uint32_t result_type = ops[0];
uint32_t id = ops[1];
auto spec_op = static_cast<Op>(ops[2]);
set<SPIRConstantOp>(id, result_type, spec_op, ops + 3, length - 3);
break;
}
// Actual opcodes.
default:
{
if (!current_block)
SPIRV_CROSS_THROW("Currently no block to insert opcode.");
current_block->ops.push_back(instruction);
break;
}
}
}
bool Compiler::block_is_loop_candidate(const SPIRBlock &block, SPIRBlock::Method method) const
{
// Tried and failed.
if (block.disable_block_optimization || block.complex_continue)
return false;
if (method == SPIRBlock::MergeToSelectForLoop)
{
// Try to detect common for loop pattern
// which the code backend can use to create cleaner code.
// for(;;) { if (cond) { some_body; } else { break; } }
// is the pattern we're looking for.
bool ret = block.terminator == SPIRBlock::Select && block.merge == SPIRBlock::MergeLoop &&
block.true_block != block.merge_block && block.true_block != block.self &&
block.false_block == block.merge_block;
// If we have OpPhi which depends on branches which came from our own block,
// we need to flush phi variables in else block instead of a trivial break,
// so we cannot assume this is a for loop candidate.
if (ret)
{
for (auto &phi : block.phi_variables)
if (phi.parent == block.self)
return false;
auto *merge = maybe_get<SPIRBlock>(block.merge_block);
if (merge)
for (auto &phi : merge->phi_variables)
if (phi.parent == block.self)
return false;
}
return ret;
}
else if (method == SPIRBlock::MergeToDirectForLoop)
{
// Empty loop header that just sets up merge target
// and branches to loop body.
bool ret = block.terminator == SPIRBlock::Direct && block.merge == SPIRBlock::MergeLoop && block.ops.empty();
if (!ret)
return false;
auto &child = get<SPIRBlock>(block.next_block);
ret = child.terminator == SPIRBlock::Select && child.merge == SPIRBlock::MergeNone &&
child.false_block == block.merge_block && child.true_block != block.merge_block &&
child.true_block != block.self;
// If we have OpPhi which depends on branches which came from our own block,
// we need to flush phi variables in else block instead of a trivial break,
// so we cannot assume this is a for loop candidate.
if (ret)
{
for (auto &phi : block.phi_variables)
if (phi.parent == block.self || phi.parent == child.self)
return false;
for (auto &phi : child.phi_variables)
if (phi.parent == block.self)
return false;
auto *merge = maybe_get<SPIRBlock>(block.merge_block);
if (merge)
for (auto &phi : merge->phi_variables)
if (phi.parent == block.self || phi.parent == child.false_block)
return false;
}
return ret;
}
else
return false;
}
bool Compiler::block_is_outside_flow_control_from_block(const SPIRBlock &from, const SPIRBlock &to)
{
auto *start = &from;
if (start->self == to.self)
return true;
// Break cycles.
if (is_continue(start->self))
return false;
// If our select block doesn't merge, we must break or continue in these blocks,
// so if continues occur branchless within these blocks, consider them branchless as well.
// This is typically used for loop control.
if (start->terminator == SPIRBlock::Select && start->merge == SPIRBlock::MergeNone &&
(block_is_outside_flow_control_from_block(get<SPIRBlock>(start->true_block), to) ||
block_is_outside_flow_control_from_block(get<SPIRBlock>(start->false_block), to)))
{
return true;
}
else if (start->merge_block && block_is_outside_flow_control_from_block(get<SPIRBlock>(start->merge_block), to))
{
return true;
}
else if (start->next_block && block_is_outside_flow_control_from_block(get<SPIRBlock>(start->next_block), to))
{
return true;
}
else
return false;
}
bool Compiler::execution_is_noop(const SPIRBlock &from, const SPIRBlock &to) const
{
if (!execution_is_branchless(from, to))
return false;
auto *start = &from;
for (;;)
{
if (start->self == to.self)
return true;
if (!start->ops.empty())
return false;
start = &get<SPIRBlock>(start->next_block);
}
}
bool Compiler::execution_is_branchless(const SPIRBlock &from, const SPIRBlock &to) const
{
auto *start = &from;
for (;;)
{
if (start->self == to.self)
return true;
if (start->terminator == SPIRBlock::Direct && start->merge == SPIRBlock::MergeNone)
start = &get<SPIRBlock>(start->next_block);
else
return false;
}
}
SPIRBlock::ContinueBlockType Compiler::continue_block_type(const SPIRBlock &block) const
{
// The block was deemed too complex during code emit, pick conservative fallback paths.
if (block.complex_continue)
return SPIRBlock::ComplexLoop;
// In older glslang output continue block can be equal to the loop header.
// In this case, execution is clearly branchless, so just assume a while loop header here.
if (block.merge == SPIRBlock::MergeLoop)
return SPIRBlock::WhileLoop;
auto &dominator = get<SPIRBlock>(block.loop_dominator);
if (execution_is_noop(block, dominator))
return SPIRBlock::WhileLoop;
else if (execution_is_branchless(block, dominator))
return SPIRBlock::ForLoop;
else
{
if (block.merge == SPIRBlock::MergeNone && block.terminator == SPIRBlock::Select &&
block.true_block == dominator.self && block.false_block == dominator.merge_block)
{
return SPIRBlock::DoWhileLoop;
}
else
return SPIRBlock::ComplexLoop;
}
}
bool Compiler::traverse_all_reachable_opcodes(const SPIRBlock &block, OpcodeHandler &handler) const
{
handler.set_current_block(block);
// Ideally, perhaps traverse the CFG instead of all blocks in order to eliminate dead blocks,
// but this shouldn't be a problem in practice unless the SPIR-V is doing insane things like recursing
// inside dead blocks ...
for (auto &i : block.ops)
{
auto ops = stream(i);
auto op = static_cast<Op>(i.op);
if (!handler.handle(op, ops, i.length))
return false;
if (op == OpFunctionCall)
{
auto &func = get<SPIRFunction>(ops[2]);
if (handler.follow_function_call(func))
{
if (!handler.begin_function_scope(ops, i.length))
return false;
if (!traverse_all_reachable_opcodes(get<SPIRFunction>(ops[2]), handler))
return false;
if (!handler.end_function_scope(ops, i.length))
return false;
}
}
}
return true;
}
bool Compiler::traverse_all_reachable_opcodes(const SPIRFunction &func, OpcodeHandler &handler) const
{
for (auto block : func.blocks)
if (!traverse_all_reachable_opcodes(get<SPIRBlock>(block), handler))
return false;
return true;
}
uint32_t Compiler::type_struct_member_offset(const SPIRType &type, uint32_t index) const
{
// Decoration must be set in valid SPIR-V, otherwise throw.
auto &dec = meta[type.self].members.at(index);
if (dec.decoration_flags & (1ull << DecorationOffset))
return dec.offset;
else
SPIRV_CROSS_THROW("Struct member does not have Offset set.");
}
uint32_t Compiler::type_struct_member_array_stride(const SPIRType &type, uint32_t index) const
{
// Decoration must be set in valid SPIR-V, otherwise throw.
// ArrayStride is part of the array type not OpMemberDecorate.
auto &dec = meta[type.member_types[index]].decoration;
if (dec.decoration_flags & (1ull << DecorationArrayStride))
return dec.array_stride;
else
SPIRV_CROSS_THROW("Struct member does not have ArrayStride set.");
}
size_t Compiler::get_declared_struct_size(const SPIRType &type) const
{
uint32_t last = uint32_t(type.member_types.size() - 1);
size_t offset = type_struct_member_offset(type, last);
size_t size = get_declared_struct_member_size(type, last);
return offset + size;
}
size_t Compiler::get_declared_struct_member_size(const SPIRType &struct_type, uint32_t index) const
{
auto flags = get_member_decoration_mask(struct_type.self, index);
auto &type = get<SPIRType>(struct_type.member_types[index]);
if (type.basetype != SPIRType::Struct)
{
switch (type.basetype)
{
case SPIRType::Unknown:
case SPIRType::Void:
case SPIRType::Boolean: // Bools are purely logical, and cannot be used for externally visible types.
case SPIRType::AtomicCounter:
case SPIRType::Image:
case SPIRType::SampledImage:
case SPIRType::Sampler:
SPIRV_CROSS_THROW("Querying size for object with opaque size.\n");
default:
break;
}
size_t component_size = type.width / 8;
unsigned vecsize = type.vecsize;
unsigned columns = type.columns;
if (type.array.empty())
{
// Vectors.
if (columns == 1)
return vecsize * component_size;
else
{
// Per SPIR-V spec, matrices must be tightly packed and aligned up for vec3 accesses.
if ((flags & (1ull << DecorationRowMajor)) && columns == 3)
columns = 4;
else if ((flags & (1ull << DecorationColMajor)) && vecsize == 3)
vecsize = 4;
return vecsize * columns * component_size;
}
}
else
{
// For arrays, we can use ArrayStride to get an easy check.
return type_struct_member_array_stride(struct_type, index) * type.array.back();
}
}
else
{
// Recurse.
uint32_t last = uint32_t(struct_type.member_types.size() - 1);
uint32_t offset = type_struct_member_offset(struct_type, last);
size_t size;
// If we have an array of structs inside our struct, handle that with array strides instead.
auto &last_type = get<SPIRType>(struct_type.member_types.back());
if (last_type.array.empty())
size = get_declared_struct_size(last_type);
else
size = type_struct_member_array_stride(struct_type, last) * last_type.array.back();
return offset + size;
}
}
bool Compiler::BufferAccessHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
if (opcode != OpAccessChain && opcode != OpInBoundsAccessChain)
return true;
// Invalid SPIR-V.
if (length < 4)
return false;
if (args[2] != id)
return true;
// Don't bother traversing the entire access chain tree yet.
// If we access a struct member, assume we access the entire member.
uint32_t index = compiler.get<SPIRConstant>(args[3]).scalar();
// Seen this index already.
if (seen.find(index) != end(seen))
return true;
seen.insert(index);
auto &type = compiler.expression_type(id);
uint32_t offset = compiler.type_struct_member_offset(type, index);
size_t range;
// If we have another member in the struct, deduce the range by looking at the next member.
// This is okay since structs in SPIR-V can have padding, but Offset decoration must be
// monotonically increasing.
// Of course, this doesn't take into account if the SPIR-V for some reason decided to add
// very large amounts of padding, but that's not really a big deal.
if (index + 1 < type.member_types.size())
{
range = compiler.type_struct_member_offset(type, index + 1) - offset;
}
else
{
// No padding, so just deduce it from the size of the member directly.
range = compiler.get_declared_struct_member_size(type, index);
}
ranges.push_back({ index, offset, range });
return true;
}
std::vector<BufferRange> Compiler::get_active_buffer_ranges(uint32_t id) const
{
std::vector<BufferRange> ranges;
BufferAccessHandler handler(*this, ranges, id);
traverse_all_reachable_opcodes(get<SPIRFunction>(entry_point), handler);
return ranges;
}
// Increase the number of IDs by the specified incremental amount.
// Returns the value of the first ID available for use in the expanded bound.
uint32_t Compiler::increase_bound_by(uint32_t incr_amount)
{
auto curr_bound = ids.size();
auto new_bound = curr_bound + incr_amount;
ids.resize(new_bound);
meta.resize(new_bound);
return uint32_t(curr_bound);
}
bool Compiler::types_are_logically_equivalent(const SPIRType &a, const SPIRType &b) const
{
if (a.basetype != b.basetype)
return false;
if (a.width != b.width)
return false;
if (a.vecsize != b.vecsize)
return false;
if (a.columns != b.columns)
return false;
if (a.array.size() != b.array.size())
return false;
size_t array_count = a.array.size();
if (array_count && memcmp(a.array.data(), b.array.data(), array_count * sizeof(uint32_t)) != 0)
return false;
if (a.basetype == SPIRType::Image || a.basetype == SPIRType::SampledImage)
{
if (memcmp(&a.image, &b.image, sizeof(SPIRType::Image)) != 0)
return false;
}
if (a.member_types.size() != b.member_types.size())
return false;
size_t member_types = a.member_types.size();
for (size_t i = 0; i < member_types; i++)
{
if (!types_are_logically_equivalent(get<SPIRType>(a.member_types[i]), get<SPIRType>(b.member_types[i])))
return false;
}
return true;
}
uint64_t Compiler::get_execution_mode_mask() const
{
return get_entry_point().flags;
}
void Compiler::set_execution_mode(ExecutionMode mode, uint32_t arg0, uint32_t arg1, uint32_t arg2)
{
auto &execution = get_entry_point();
execution.flags |= 1ull << mode;
switch (mode)
{
case ExecutionModeLocalSize:
execution.workgroup_size.x = arg0;
execution.workgroup_size.y = arg1;
execution.workgroup_size.z = arg2;
break;
case ExecutionModeInvocations:
execution.invocations = arg0;
break;
case ExecutionModeOutputVertices:
execution.output_vertices = arg0;
break;
default:
break;
}
}
void Compiler::unset_execution_mode(ExecutionMode mode)
{
auto &execution = get_entry_point();
execution.flags &= ~(1ull << mode);
}
uint32_t Compiler::get_execution_mode_argument(spv::ExecutionMode mode, uint32_t index) const
{
auto &execution = get_entry_point();
switch (mode)
{
case ExecutionModeLocalSize:
switch (index)
{
case 0:
return execution.workgroup_size.x;
case 1:
return execution.workgroup_size.y;
case 2:
return execution.workgroup_size.z;
default:
return 0;
}
case ExecutionModeInvocations:
return execution.invocations;
case ExecutionModeOutputVertices:
return execution.output_vertices;
default:
return 0;
}
}
ExecutionModel Compiler::get_execution_model() const
{
auto &execution = get_entry_point();
return execution.model;
}
void Compiler::set_remapped_variable_state(uint32_t id, bool remap_enable)
{
get<SPIRVariable>(id).remapped_variable = remap_enable;
}
bool Compiler::get_remapped_variable_state(uint32_t id) const
{
return get<SPIRVariable>(id).remapped_variable;
}
void Compiler::set_subpass_input_remapped_components(uint32_t id, uint32_t components)
{
get<SPIRVariable>(id).remapped_components = components;
}
uint32_t Compiler::get_subpass_input_remapped_components(uint32_t id) const
{
return get<SPIRVariable>(id).remapped_components;
}
void Compiler::inherit_expression_dependencies(uint32_t dst, uint32_t source_expression)
{
auto &e = get<SPIRExpression>(dst);
auto *s = maybe_get<SPIRExpression>(source_expression);
if (!s)
return;
auto &e_deps = e.expression_dependencies;
auto &s_deps = s->expression_dependencies;
// If we depend on a expression, we also depend on all sub-dependencies from source.
e_deps.push_back(source_expression);
e_deps.insert(end(e_deps), begin(s_deps), end(s_deps));
// Eliminate duplicated dependencies.
e_deps.erase(unique(begin(e_deps), end(e_deps)), end(e_deps));
}
vector<string> Compiler::get_entry_points() const
{
vector<string> entries;
for (auto &entry : entry_points)
entries.push_back(entry.second.name);
return entries;
}
void Compiler::set_entry_point(const std::string &name)
{
auto &entry = get_entry_point(name);
entry_point = entry.self;
}
SPIREntryPoint &Compiler::get_entry_point(const std::string &name)
{
auto itr =
find_if(begin(entry_points), end(entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool { return entry.second.name == name; });
if (itr == end(entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
const SPIREntryPoint &Compiler::get_entry_point(const std::string &name) const
{
auto itr =
find_if(begin(entry_points), end(entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool { return entry.second.name == name; });
if (itr == end(entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
const SPIREntryPoint &Compiler::get_entry_point() const
{
return entry_points.find(entry_point)->second;
}
SPIREntryPoint &Compiler::get_entry_point()
{
return entry_points.find(entry_point)->second;
}
bool Compiler::interface_variable_exists_in_entry_point(uint32_t id) const
{
auto &var = get<SPIRVariable>(id);
if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
SPIRV_CROSS_THROW("Only Input and Output variables are part of a shader linking interface.");
// This is to avoid potential problems with very old glslang versions which did
// not emit input/output interfaces properly.
// We can assume they only had a single entry point, and single entry point
// shaders could easily be assumed to use every interface variable anyways.
if (entry_points.size() <= 1)
return true;
auto &execution = get_entry_point();
return find(begin(execution.interface_variables), end(execution.interface_variables), id) !=
end(execution.interface_variables);
}
void Compiler::CombinedImageSamplerHandler::push_remap_parameters(const SPIRFunction &func, const uint32_t *args,
uint32_t length)
{
// If possible, pipe through a remapping table so that parameters know
// which variables they actually bind to in this scope.
unordered_map<uint32_t, uint32_t> remapping;
for (uint32_t i = 0; i < length; i++)
remapping[func.arguments[i].id] = remap_parameter(args[i]);
parameter_remapping.push(move(remapping));
}
void Compiler::CombinedImageSamplerHandler::pop_remap_parameters()
{
parameter_remapping.pop();
}
uint32_t Compiler::CombinedImageSamplerHandler::remap_parameter(uint32_t id)
{
auto *var = compiler.maybe_get_backing_variable(id);
if (var)
id = var->self;
if (parameter_remapping.empty())
return id;
auto &remapping = parameter_remapping.top();
auto itr = remapping.find(id);
if (itr != end(remapping))
return itr->second;
else
return id;
}
bool Compiler::CombinedImageSamplerHandler::begin_function_scope(const uint32_t *args, uint32_t length)
{
if (length < 3)
return false;
auto &callee = compiler.get<SPIRFunction>(args[2]);
args += 3;
length -= 3;
push_remap_parameters(callee, args, length);
functions.push(&callee);
return true;
}
bool Compiler::CombinedImageSamplerHandler::end_function_scope(const uint32_t *args, uint32_t length)
{
if (length < 3)
return false;
auto &callee = compiler.get<SPIRFunction>(args[2]);
args += 3;
length -= 3;
// There are two types of cases we have to handle,
// a callee might call sampler2D(texture2D, sampler) directly where
// one or more parameters originate from parameters.
// Alternatively, we need to provide combined image samplers to our callees,
// and in this case we need to add those as well.
pop_remap_parameters();
// Our callee has now been processed at least once.
// No point in doing it again.
callee.do_combined_parameters = false;
auto &params = functions.top()->combined_parameters;
functions.pop();
if (functions.empty())
return true;
auto &caller = *functions.top();
if (caller.do_combined_parameters)
{
for (auto &param : params)
{
uint32_t image_id = param.global_image ? param.image_id : args[param.image_id];
uint32_t sampler_id = param.global_sampler ? param.sampler_id : args[param.sampler_id];
auto *i = compiler.maybe_get_backing_variable(image_id);
auto *s = compiler.maybe_get_backing_variable(sampler_id);
if (i)
image_id = i->self;
if (s)
sampler_id = s->self;
register_combined_image_sampler(caller, image_id, sampler_id);
}
}
return true;
}
void Compiler::CombinedImageSamplerHandler::register_combined_image_sampler(SPIRFunction &caller, uint32_t image_id,
uint32_t sampler_id)
{
// We now have a texture ID and a sampler ID which will either be found as a global
// or a parameter in our own function. If both are global, they will not need a parameter,
// otherwise, add it to our list.
SPIRFunction::CombinedImageSamplerParameter param = {
0u, image_id, sampler_id, true, true,
};
auto texture_itr = find_if(begin(caller.arguments), end(caller.arguments),
[image_id](const SPIRFunction::Parameter &p) { return p.id == image_id; });
auto sampler_itr = find_if(begin(caller.arguments), end(caller.arguments),
[sampler_id](const SPIRFunction::Parameter &p) { return p.id == sampler_id; });
if (texture_itr != end(caller.arguments))
{
param.global_image = false;
param.image_id = uint32_t(texture_itr - begin(caller.arguments));
}
if (sampler_itr != end(caller.arguments))
{
param.global_sampler = false;
param.sampler_id = uint32_t(sampler_itr - begin(caller.arguments));
}
if (param.global_image && param.global_sampler)
return;
auto itr = find_if(begin(caller.combined_parameters), end(caller.combined_parameters),
[&param](const SPIRFunction::CombinedImageSamplerParameter &p) {
return param.image_id == p.image_id && param.sampler_id == p.sampler_id &&
param.global_image == p.global_image && param.global_sampler == p.global_sampler;
});
if (itr == end(caller.combined_parameters))
{
uint32_t id = compiler.increase_bound_by(3);
auto type_id = id + 0;
auto ptr_type_id = id + 1;
auto combined_id = id + 2;
auto &base = compiler.expression_type(image_id);
auto &type = compiler.set<SPIRType>(type_id);
auto &ptr_type = compiler.set<SPIRType>(ptr_type_id);
type = base;
type.self = type_id;
type.basetype = SPIRType::SampledImage;
type.pointer = false;
type.storage = StorageClassGeneric;
ptr_type = type;
ptr_type.pointer = true;
ptr_type.storage = StorageClassUniformConstant;
// Build new variable.
compiler.set<SPIRVariable>(combined_id, ptr_type_id, StorageClassFunction, 0);
// Inherit RelaxedPrecision (and potentially other useful flags if deemed relevant).
auto &new_flags = compiler.meta[combined_id].decoration.decoration_flags;
auto old_flags = compiler.meta[sampler_id].decoration.decoration_flags;
new_flags = old_flags & (1ull << DecorationRelaxedPrecision);
param.id = combined_id;
compiler.set_name(combined_id,
join("SPIRV_Cross_Combined", compiler.to_name(image_id), compiler.to_name(sampler_id)));
caller.combined_parameters.push_back(param);
caller.shadow_arguments.push_back({ ptr_type_id, combined_id, 0u, 0u });
}
}
bool Compiler::CombinedImageSamplerHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
// We need to figure out where samplers and images are loaded from, so do only the bare bones compilation we need.
switch (opcode)
{
case OpLoad:
{
if (length < 3)
return false;
uint32_t result_type = args[0];
auto &type = compiler.get<SPIRType>(result_type);
bool separate_image = type.basetype == SPIRType::Image && type.image.sampled == 1;
bool separate_sampler = type.basetype == SPIRType::Sampler;
// If not separate image or sampler, don't bother.
if (!separate_image && !separate_sampler)
return true;
uint32_t id = args[1];
uint32_t ptr = args[2];
compiler.set<SPIRExpression>(id, "", result_type, true);
compiler.register_read(id, ptr, true);
return true;
}
case OpInBoundsAccessChain:
case OpAccessChain:
{
if (length < 3)
return false;
// Technically, it is possible to have arrays of textures and arrays of samplers and combine them, but this becomes essentially
// impossible to implement, since we don't know which concrete sampler we are accessing.
// One potential way is to create a combinatorial explosion where N textures and M samplers are combined into N * M sampler2Ds,
// but this seems ridiculously complicated for a problem which is easy to work around.
// Checking access chains like this assumes we don't have samplers or textures inside uniform structs, but this makes no sense.
auto &type = compiler.get<SPIRType>(args[0]);
bool separate_image = type.basetype == SPIRType::Image && type.image.sampled == 1;
bool separate_sampler = type.basetype == SPIRType::Sampler;
if (separate_image)
SPIRV_CROSS_THROW(
"Attempting to use arrays of separate images. This is not possible to statically remap to plain GLSL.");
if (separate_sampler)
SPIRV_CROSS_THROW("Attempting to use arrays of separate samplers. This is not possible to statically "
"remap to plain GLSL.");
return true;
}
case OpSampledImage:
// Do it outside.
break;
default:
return true;
}
if (length < 4)
return false;
// Registers sampler2D calls used in case they are parameters so
// that their callees know which combined image samplers to propagate down the call stack.
if (!functions.empty())
{
auto &callee = *functions.top();
if (callee.do_combined_parameters)
{
uint32_t image_id = args[2];
auto *image = compiler.maybe_get_backing_variable(image_id);
if (image)
image_id = image->self;
uint32_t sampler_id = args[3];
auto *sampler = compiler.maybe_get_backing_variable(sampler_id);
if (sampler)
sampler_id = sampler->self;
register_combined_image_sampler(callee, image_id, sampler_id);
}
}
// For function calls, we need to remap IDs which are function parameters into global variables.
// This information is statically known from the current place in the call stack.
// Function parameters are not necessarily pointers, so if we don't have a backing variable, remapping will know
// which backing variable the image/sample came from.
uint32_t image_id = remap_parameter(args[2]);
uint32_t sampler_id = remap_parameter(args[3]);
auto itr = find_if(begin(compiler.combined_image_samplers), end(compiler.combined_image_samplers),
[image_id, sampler_id](const CombinedImageSampler &combined) {
return combined.image_id == image_id && combined.sampler_id == sampler_id;
});
if (itr == end(compiler.combined_image_samplers))
{
auto id = compiler.increase_bound_by(2);
auto type_id = id + 0;
auto combined_id = id + 1;
auto sampled_type = args[0];
// Make a new type, pointer to OpTypeSampledImage, so we can make a variable of this type.
// We will probably have this type lying around, but it doesn't hurt to make duplicates for internal purposes.
auto &type = compiler.set<SPIRType>(type_id);
auto &base = compiler.get<SPIRType>(sampled_type);
type = base;
type.pointer = true;
type.storage = StorageClassUniformConstant;
// Build new variable.
compiler.set<SPIRVariable>(combined_id, type_id, StorageClassUniformConstant, 0);
// Inherit RelaxedPrecision (and potentially other useful flags if deemed relevant).
auto &new_flags = compiler.meta[combined_id].decoration.decoration_flags;
auto old_flags = compiler.meta[sampler_id].decoration.decoration_flags;
new_flags = old_flags & (1ull << DecorationRelaxedPrecision);
compiler.combined_image_samplers.push_back({ combined_id, image_id, sampler_id });
}
return true;
}
void Compiler::build_combined_image_samplers()
{
for (auto &id : ids)
{
if (id.get_type() == TypeFunction)
{
auto &func = id.get<SPIRFunction>();
func.combined_parameters.clear();
func.shadow_arguments.clear();
func.do_combined_parameters = true;
}
}
combined_image_samplers.clear();
CombinedImageSamplerHandler handler(*this);
traverse_all_reachable_opcodes(get<SPIRFunction>(entry_point), handler);
}
vector<SpecializationConstant> Compiler::get_specialization_constants() const
{
vector<SpecializationConstant> spec_consts;
for (auto &id : ids)
{
if (id.get_type() == TypeConstant)
{
auto &c = id.get<SPIRConstant>();
if (c.specialization)
{
spec_consts.push_back({ c.self, get_decoration(c.self, DecorationSpecId) });
}
}
}
return spec_consts;
}
SPIRConstant &Compiler::get_constant(uint32_t id)
{
return get<SPIRConstant>(id);
}
const SPIRConstant &Compiler::get_constant(uint32_t id) const
{
return get<SPIRConstant>(id);
}
void Compiler::analyze_variable_scope(SPIRFunction &entry)
{
struct AccessHandler : OpcodeHandler
{
public:
AccessHandler(Compiler &compiler_)
: compiler(compiler_)
{
}
bool follow_function_call(const SPIRFunction &)
{
// Only analyze within this function.
return false;
}
void set_current_block(const SPIRBlock &block)
{
current_block = &block;
// If we're branching to a block which uses OpPhi, in GLSL
// this will be a variable write when we branch,
// so we need to track access to these variables as well to
// have a complete picture.
const auto test_phi = [this, &block](uint32_t to) {
auto &next = compiler.get<SPIRBlock>(to);
for (auto &phi : next.phi_variables)
if (phi.parent == block.self)
accessed_variables_to_block[phi.function_variable].insert(block.self);
};
switch (block.terminator)
{
case SPIRBlock::Direct:
test_phi(block.next_block);
break;
case SPIRBlock::Select:
test_phi(block.true_block);
test_phi(block.false_block);
break;
case SPIRBlock::MultiSelect:
for (auto &target : block.cases)
test_phi(target.block);
if (block.default_block)
test_phi(block.default_block);
break;
default:
break;
}
}
bool handle(spv::Op op, const uint32_t *args, uint32_t length)
{
switch (op)
{
case OpStore:
{
if (length < 2)
return false;
uint32_t ptr = args[0];
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpAccessChain:
case OpInBoundsAccessChain:
{
if (length < 3)
return false;
uint32_t ptr = args[2];
auto *var = compiler.maybe_get<SPIRVariable>(ptr);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpCopyMemory:
{
if (length < 3)
return false;
uint32_t lhs = args[0];
uint32_t rhs = args[1];
auto *var = compiler.maybe_get_backing_variable(lhs);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
var = compiler.maybe_get_backing_variable(rhs);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpCopyObject:
{
if (length < 3)
return false;
auto *var = compiler.maybe_get_backing_variable(args[2]);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpLoad:
{
if (length < 3)
return false;
uint32_t ptr = args[2];
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpFunctionCall:
{
if (length < 3)
return false;
length -= 3;
args += 3;
for (uint32_t i = 0; i < length; i++)
{
auto *var = compiler.maybe_get_backing_variable(args[i]);
if (var && var->storage == StorageClassFunction)
accessed_variables_to_block[var->self].insert(current_block->self);
}
break;
}
case OpPhi:
{
if (length < 2)
return false;
// Phi nodes are implemented as function variables, so register an access here.
accessed_variables_to_block[args[1]].insert(current_block->self);
break;
}
// Atomics shouldn't be able to access function-local variables.
// Some GLSL builtins access a pointer.
default:
break;
}
return true;
}
Compiler &compiler;
std::unordered_map<uint32_t, std::unordered_set<uint32_t>> accessed_variables_to_block;
const SPIRBlock *current_block = nullptr;
} handler(*this);
// First, we map out all variable access within a function.
// Essentially a map of block -> { variables accessed in the basic block }
this->traverse_all_reachable_opcodes(entry, handler);
// Compute the control flow graph for this function.
CFG cfg(*this, entry);
unordered_map<uint32_t, uint32_t> potential_loop_variables;
// For each variable which is statically accessed.
for (auto &var : handler.accessed_variables_to_block)
{
DominatorBuilder builder(cfg);
auto &blocks = var.second;
auto &type = expression_type(var.first);
// Figure out which block is dominating all accesses of those variables.
for (auto &block : blocks)
{
// If we're accessing a variable inside a continue block, this variable might be a loop variable.
// We can only use loop variables with scalars, as we cannot track static expressions for vectors.
if (is_continue(block) && type.vecsize == 1 && type.columns == 1)
{
// The variable is used in multiple continue blocks, this is not a loop
// candidate, signal that by setting block to -1u.
auto &potential = potential_loop_variables[var.first];
if (potential == 0)
potential = block;
else
potential = ~(0u);
}
builder.add_block(block);
}
builder.lift_continue_block_dominator();
// Add it to a per-block list of variables.
uint32_t dominating_block = builder.get_dominator();
// If all blocks here are dead code, this will be 0, so the variable in question
// will be completely eliminated.
if (dominating_block)
{
auto &block = this->get<SPIRBlock>(dominating_block);
block.dominated_variables.push_back(var.first);
get<SPIRVariable>(var.first).dominator = dominating_block;
}
}
// Now, try to analyze whether or not these variables are actually loop variables.
for (auto &loop_variable : potential_loop_variables)
{
auto &var = get<SPIRVariable>(loop_variable.first);
auto dominator = var.dominator;
auto block = loop_variable.second;
// The variable was accessed in multiple continue blocks, ignore.
if (block == ~(0u) || block == 0)
continue;
// Dead code.
if (dominator == 0)
continue;
uint32_t header = 0;
// Find the loop header for this block.
for (auto b : loop_blocks)
{
auto &potential_header = get<SPIRBlock>(b);
if (potential_header.continue_block == block)
{
header = b;
break;
}
}
assert(header);
auto &header_block = get<SPIRBlock>(header);
// Now, there are two conditions we need to meet for the variable to be a loop variable.
// 1. The dominating block must have a branch-free path to the loop header,
// this way we statically know which expression should be part of the loop variable initializer.
// Walk from the dominator, if there is one straight edge connecting
// dominator and loop header, we statically know the loop initializer.
bool static_loop_init = true;
while (dominator != header)
{
auto &succ = cfg.get_succeeding_edges(dominator);
if (succ.size() != 1)
{
static_loop_init = false;
break;
}
auto &pred = cfg.get_preceding_edges(succ.front());
if (pred.size() != 1 || pred.front() != dominator)
{
static_loop_init = false;
break;
}
dominator = succ.front();
}
if (!static_loop_init)
continue;
// The second condition we need to meet is that no access after the loop
// merge can occur. Walk the CFG to see if we find anything.
auto &blocks = handler.accessed_variables_to_block[loop_variable.first];
cfg.walk_from(header_block.merge_block, [&](uint32_t walk_block) {
// We found a block which accesses the variable outside the loop.
if (blocks.find(walk_block) != end(blocks))
static_loop_init = false;
});
if (!static_loop_init)
continue;
// We have a loop variable.
header_block.loop_variables.push_back(loop_variable.first);
// Need to sort here as variables come from an unordered container, and pushing stuff in wrong order
// will break reproducability in regression runs.
sort(begin(header_block.loop_variables), end(header_block.loop_variables));
get<SPIRVariable>(loop_variable.first).loop_variable = true;
}
}
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