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SPIRV-Cross/spirv_cross.cpp
Hans-Kristian Arntzen 04ddb9a809 Mark function call results as control dependent as necessary. 
Inner function calls can contain flow-control sensitive code.
In this case, the function call itself must inherit the
control-dependence.

Rarely happens in practice since optimized code with SSA tends to
inline.
2024-05-10 14:52:24 +02:00

5669 lines
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/*
* Copyright 2015-2021 Arm Limited
* SPDX-License-Identifier: Apache-2.0 OR MIT
*
* 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.
*/
/*
* At your option, you may choose to accept this material under either:
* 1. The Apache License, Version 2.0, found at <http://www.apache.org/licenses/LICENSE-2.0>, or
* 2. The MIT License, found at <http://opensource.org/licenses/MIT>.
*/
#include "spirv_cross.hpp"
#include "GLSL.std.450.h"
#include "spirv_cfg.hpp"
#include "spirv_common.hpp"
#include "spirv_parser.hpp"
#include <algorithm>
#include <cstring>
#include <utility>
using namespace std;
using namespace spv;
using namespace SPIRV_CROSS_NAMESPACE;
Compiler::Compiler(vector<uint32_t> ir_)
{
Parser parser(std::move(ir_));
parser.parse();
set_ir(std::move(parser.get_parsed_ir()));
}
Compiler::Compiler(const uint32_t *ir_, size_t word_count)
{
Parser parser(ir_, word_count);
parser.parse();
set_ir(std::move(parser.get_parsed_ir()));
}
Compiler::Compiler(const ParsedIR &ir_)
{
set_ir(ir_);
}
Compiler::Compiler(ParsedIR &&ir_)
{
set_ir(std::move(ir_));
}
void Compiler::set_ir(ParsedIR &&ir_)
{
ir = std::move(ir_);
parse_fixup();
}
void Compiler::set_ir(const ParsedIR &ir_)
{
ir = ir_;
parse_fixup();
}
string Compiler::compile()
{
return "";
}
bool Compiler::variable_storage_is_aliased(const SPIRVariable &v)
{
auto &type = get<SPIRType>(v.basetype);
bool ssbo = v.storage == StorageClassStorageBuffer ||
ir.meta[type.self].decoration.decoration_flags.get(DecorationBufferBlock);
bool image = type.basetype == SPIRType::Image;
bool counter = type.basetype == SPIRType::AtomicCounter;
bool buffer_reference = type.storage == StorageClassPhysicalStorageBufferEXT;
bool is_restrict;
if (ssbo)
is_restrict = ir.get_buffer_block_flags(v).get(DecorationRestrict);
else
is_restrict = has_decoration(v.self, DecorationRestrict);
return !is_restrict && (ssbo || image || counter || buffer_reference);
}
bool Compiler::block_is_control_dependent(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_control_dependent(get<SPIRFunction>(func)))
return true;
break;
}
// Derivatives
case OpDPdx:
case OpDPdxCoarse:
case OpDPdxFine:
case OpDPdy:
case OpDPdyCoarse:
case OpDPdyFine:
case OpFwidth:
case OpFwidthCoarse:
case OpFwidthFine:
// Anything implicit LOD
case OpImageSampleImplicitLod:
case OpImageSampleDrefImplicitLod:
case OpImageSampleProjImplicitLod:
case OpImageSampleProjDrefImplicitLod:
case OpImageSparseSampleImplicitLod:
case OpImageSparseSampleDrefImplicitLod:
case OpImageSparseSampleProjImplicitLod:
case OpImageSparseSampleProjDrefImplicitLod:
case OpImageQueryLod:
case OpImageDrefGather:
case OpImageGather:
case OpImageSparseDrefGather:
case OpImageSparseGather:
// Anything subgroups
case OpGroupNonUniformElect:
case OpGroupNonUniformAll:
case OpGroupNonUniformAny:
case OpGroupNonUniformAllEqual:
case OpGroupNonUniformBroadcast:
case OpGroupNonUniformBroadcastFirst:
case OpGroupNonUniformBallot:
case OpGroupNonUniformInverseBallot:
case OpGroupNonUniformBallotBitExtract:
case OpGroupNonUniformBallotBitCount:
case OpGroupNonUniformBallotFindLSB:
case OpGroupNonUniformBallotFindMSB:
case OpGroupNonUniformShuffle:
case OpGroupNonUniformShuffleXor:
case OpGroupNonUniformShuffleUp:
case OpGroupNonUniformShuffleDown:
case OpGroupNonUniformIAdd:
case OpGroupNonUniformFAdd:
case OpGroupNonUniformIMul:
case OpGroupNonUniformFMul:
case OpGroupNonUniformSMin:
case OpGroupNonUniformUMin:
case OpGroupNonUniformFMin:
case OpGroupNonUniformSMax:
case OpGroupNonUniformUMax:
case OpGroupNonUniformFMax:
case OpGroupNonUniformBitwiseAnd:
case OpGroupNonUniformBitwiseOr:
case OpGroupNonUniformBitwiseXor:
case OpGroupNonUniformLogicalAnd:
case OpGroupNonUniformLogicalOr:
case OpGroupNonUniformLogicalXor:
case OpGroupNonUniformQuadBroadcast:
case OpGroupNonUniformQuadSwap:
// Control barriers
case OpControlBarrier:
return true;
default:
break;
}
}
return false;
}
bool Compiler::block_is_pure(const SPIRBlock &block)
{
// This is a global side effect of the function.
if (block.terminator == SPIRBlock::Kill ||
block.terminator == SPIRBlock::TerminateRay ||
block.terminator == SPIRBlock::IgnoreIntersection ||
block.terminator == SPIRBlock::EmitMeshTasks)
return false;
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 OpAtomicCompareExchangeWeak:
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;
// Mesh shader functions modify global state.
// (EmitMeshTasks is a terminator).
case OpSetMeshOutputsEXT:
return false;
// Barriers disallow any reordering, so we should treat blocks with barrier as writing.
case OpControlBarrier:
case OpMemoryBarrier:
return false;
// Ray tracing builtins are impure.
case OpReportIntersectionKHR:
case OpIgnoreIntersectionNV:
case OpTerminateRayNV:
case OpTraceNV:
case OpTraceRayKHR:
case OpExecuteCallableNV:
case OpExecuteCallableKHR:
case OpRayQueryInitializeKHR:
case OpRayQueryTerminateKHR:
case OpRayQueryGenerateIntersectionKHR:
case OpRayQueryConfirmIntersectionKHR:
case OpRayQueryProceedKHR:
// There are various getters in ray query, but they are considered pure.
return false;
// OpExtInst is potentially impure depending on extension, but GLSL builtins are at least pure.
case OpDemoteToHelperInvocationEXT:
// This is a global side effect of the function.
return false;
case OpExtInst:
{
uint32_t extension_set = ops[2];
if (get<SPIRExtension>(extension_set).ext == SPIRExtension::GLSL)
{
auto op_450 = static_cast<GLSLstd450>(ops[3]);
switch (op_450)
{
case GLSLstd450Modf:
case GLSLstd450Frexp:
{
auto &type = expression_type(ops[5]);
if (type.storage != StorageClassFunction)
return false;
break;
}
default:
break;
}
}
break;
}
default:
break;
}
}
return true;
}
string Compiler::to_name(uint32_t id, bool allow_alias) const
{
if (allow_alias && ir.ids[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)
{
// If the alias master has been specially packed, we will have emitted a clean variant as well,
// so skip the name aliasing here.
if (!has_extended_decoration(type.type_alias, SPIRVCrossDecorationBufferBlockRepacked))
return to_name(type.type_alias);
}
}
auto &alias = ir.get_name(id);
if (alias.empty())
return join("_", id);
else
return alias;
}
bool Compiler::function_is_pure(const SPIRFunction &func)
{
for (auto block : func.blocks)
if (!block_is_pure(get<SPIRBlock>(block)))
return false;
return true;
}
bool Compiler::function_is_control_dependent(const SPIRFunction &func)
{
for (auto block : func.blocks)
if (block_is_control_dependent(get<SPIRBlock>(block)))
return true;
return false;
}
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);
auto *access_chain = maybe_get<SPIRAccessChain>(chain);
if (access_chain)
var = maybe_get<SPIRVariable>(access_chain->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);
auto *access_chain = maybe_get<SPIRAccessChain>(chain);
if (access_chain && access_chain->loaded_from)
var = maybe_get<SPIRVariable>(access_chain->loaded_from);
}
auto &chain_type = expression_type(chain);
if (var)
{
bool check_argument_storage_qualifier = true;
auto &type = expression_type(chain);
// If our variable is in a storage class which can alias with other buffers,
// invalidate all variables which depend on aliased variables. And if this is a
// variable pointer, then invalidate all variables regardless.
if (get_variable_data_type(*var).pointer)
{
flush_all_active_variables();
if (type.pointer_depth == 1)
{
// We have a backing variable which is a pointer-to-pointer type.
// We are storing some data through a pointer acquired through that variable,
// but we are not writing to the value of the variable itself,
// i.e., we are not modifying the pointer directly.
// If we are storing a non-pointer type (pointer_depth == 1),
// we know that we are storing some unrelated data.
// A case here would be
// void foo(Foo * const *arg) {
// Foo *bar = *arg;
// bar->unrelated = 42;
// }
// arg, the argument is constant.
check_argument_storage_qualifier = false;
}
}
if (type.storage == StorageClassPhysicalStorageBufferEXT || 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 (check_argument_storage_qualifier && var->parameter && var->parameter->write_count == 0)
{
var->parameter->write_count++;
force_recompile();
}
}
else if (chain_type.pointer)
{
// If we stored through a variable pointer, then we don't know which
// variable we stored to. So *all* expressions after this point need to
// be invalidated.
// FIXME: If we can prove that the variable pointer will point to
// only certain variables, we can invalidate only those.
flush_all_active_variables();
}
// If chain_type.pointer is false, we're not writing to memory backed variables, but temporaries instead.
// This can happen in copy_logical_type where we unroll complex reads and writes to temporaries.
}
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_control_dependent_expressions(uint32_t block_id)
{
auto &block = get<SPIRBlock>(block_id);
for (auto &expr : block.invalidate_expressions)
invalid_expressions.insert(expr);
block.invalidate_expressions.clear();
}
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();
}
uint32_t Compiler::expression_type_id(uint32_t id) const
{
switch (ir.ids[id].get_type())
{
case TypeVariable:
return get<SPIRVariable>(id).basetype;
case TypeExpression:
return get<SPIRExpression>(id).expression_type;
case TypeConstant:
return get<SPIRConstant>(id).constant_type;
case TypeConstantOp:
return get<SPIRConstantOp>(id).basetype;
case TypeUndef:
return get<SPIRUndef>(id).basetype;
case TypeCombinedImageSampler:
return get<SPIRCombinedImageSampler>(id).combined_type;
case TypeAccessChain:
return get<SPIRAccessChain>(id).basetype;
default:
SPIRV_CROSS_THROW("Cannot resolve expression type.");
}
}
const SPIRType &Compiler::expression_type(uint32_t id) const
{
return get<SPIRType>(expression_type_id(id));
}
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 (ir.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 (ir.ids[id].get_type() == TypeAccessChain)
return get<SPIRAccessChain>(id).immutable;
else if (ir.ids[id].get_type() == TypeExpression)
return get<SPIRExpression>(id).immutable;
else if (ir.ids[id].get_type() == TypeConstant || ir.ids[id].get_type() == TypeConstantOp ||
ir.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:
case StorageClassStorageBuffer:
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;
}
// In SPIR-V 1.4 and up we must also use the active variable interface to disable global variables
// which are not part of the entry point.
if (ir.get_spirv_version() >= 0x10400 && var.storage != spv::StorageClassGeneric &&
var.storage != spv::StorageClassFunction && !interface_variable_exists_in_entry_point(var.self))
{
return true;
}
return check_active_interface_variables && storage_class_is_interface(var.storage) &&
active_interface_variables.find(var.self) == end(active_interface_variables);
}
bool Compiler::is_builtin_type(const SPIRType &type) const
{
auto *type_meta = ir.find_meta(type.self);
// We can have builtin structs as well. If one member of a struct is builtin, the struct must also be builtin.
if (type_meta)
for (auto &m : type_meta->members)
if (m.builtin)
return true;
return false;
}
bool Compiler::is_builtin_variable(const SPIRVariable &var) const
{
auto *m = ir.find_meta(var.self);
if (var.compat_builtin || (m && m->decoration.builtin))
return true;
else
return is_builtin_type(get<SPIRType>(var.basetype));
}
bool Compiler::is_member_builtin(const SPIRType &type, uint32_t index, BuiltIn *builtin) const
{
auto *type_meta = ir.find_meta(type.self);
if (type_meta)
{
auto &memb = type_meta->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.basetype != SPIRType::Struct && 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;
}
bool Compiler::is_array(const SPIRType &type) const
{
return type.op == OpTypeArray || type.op == OpTypeRuntimeArray;
}
bool Compiler::is_pointer(const SPIRType &type) const
{
return type.op == OpTypePointer && type.basetype != SPIRType::Unknown; // Ignore function pointers.
}
bool Compiler::is_physical_pointer(const SPIRType &type) const
{
return type.op == OpTypePointer && type.storage == StorageClassPhysicalStorageBuffer;
}
bool Compiler::is_physical_pointer_to_buffer_block(const SPIRType &type) const
{
return is_physical_pointer(type) && get_pointee_type(type).self == type.parent_type &&
(has_decoration(type.self, DecorationBlock) ||
has_decoration(type.self, DecorationBufferBlock));
}
bool Compiler::is_runtime_size_array(const SPIRType &type)
{
return type.op == OpTypeRuntimeArray;
}
ShaderResources Compiler::get_shader_resources() const
{
return get_shader_resources(nullptr);
}
ShaderResources Compiler::get_shader_resources(const unordered_set<VariableID> &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 OpSelect:
{
// Invalid SPIR-V.
if (length < 5)
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 OpPhi:
{
// Invalid SPIR-V.
if (length < 2)
return false;
uint32_t count = length - 2;
args += 2;
for (uint32_t i = 0; i < count; i += 2)
{
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 < 2)
return false;
auto *var = compiler.maybe_get<SPIRVariable>(args[0]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[0]);
var = compiler.maybe_get<SPIRVariable>(args[1]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[1]);
break;
}
case OpExtInst:
{
if (length < 3)
return false;
auto &extension_set = compiler.get<SPIRExtension>(args[2]);
switch (extension_set.ext)
{
case SPIRExtension::GLSL:
{
auto op = static_cast<GLSLstd450>(args[3]);
switch (op)
{
case GLSLstd450InterpolateAtCentroid:
case GLSLstd450InterpolateAtSample:
case GLSLstd450InterpolateAtOffset:
{
auto *var = compiler.maybe_get<SPIRVariable>(args[4]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[4]);
break;
}
case GLSLstd450Modf:
case GLSLstd450Fract:
{
auto *var = compiler.maybe_get<SPIRVariable>(args[5]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[5]);
break;
}
default:
break;
}
break;
}
case SPIRExtension::SPV_AMD_shader_explicit_vertex_parameter:
{
enum AMDShaderExplicitVertexParameter
{
InterpolateAtVertexAMD = 1
};
auto op = static_cast<AMDShaderExplicitVertexParameter>(args[3]);
switch (op)
{
case InterpolateAtVertexAMD:
{
auto *var = compiler.maybe_get<SPIRVariable>(args[4]);
if (var && storage_class_is_interface(var->storage))
variables.insert(args[4]);
break;
}
default:
break;
}
break;
}
default:
break;
}
break;
}
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
case OpLoad:
case OpCopyObject:
case OpImageTexelPointer:
case OpAtomicLoad:
case OpAtomicExchange:
case OpAtomicCompareExchange:
case OpAtomicCompareExchangeWeak:
case OpAtomicIIncrement:
case OpAtomicIDecrement:
case OpAtomicIAdd:
case OpAtomicISub:
case OpAtomicSMin:
case OpAtomicUMin:
case OpAtomicSMax:
case OpAtomicUMax:
case OpAtomicAnd:
case OpAtomicOr:
case OpAtomicXor:
case OpArrayLength:
// 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<VariableID> Compiler::get_active_interface_variables() const
{
// Traverse the call graph and find all interface variables which are in use.
unordered_set<VariableID> variables;
InterfaceVariableAccessHandler handler(*this, variables);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
ir.for_each_typed_id<SPIRVariable>([&](uint32_t, const SPIRVariable &var) {
if (var.storage != StorageClassOutput)
return;
if (!interface_variable_exists_in_entry_point(var.self))
return;
// An output variable which is just declared (but uninitialized) might be read by subsequent stages
// so we should force-enable these outputs,
// since compilation will fail if a subsequent stage attempts to read from the variable in question.
// Also, make sure we preserve output variables which are only initialized, but never accessed by any code.
if (var.initializer != ID(0) || get_execution_model() != ExecutionModelFragment)
variables.insert(var.self);
});
// If we needed to create one, we'll need it.
if (dummy_sampler_id)
variables.insert(dummy_sampler_id);
return variables;
}
void Compiler::set_enabled_interface_variables(std::unordered_set<VariableID> active_variables)
{
active_interface_variables = std::move(active_variables);
check_active_interface_variables = true;
}
ShaderResources Compiler::get_shader_resources(const unordered_set<VariableID> *active_variables) const
{
ShaderResources res;
bool ssbo_instance_name = reflection_ssbo_instance_name_is_significant();
ir.for_each_typed_id<SPIRVariable>([&](uint32_t, const SPIRVariable &var) {
auto &type = this->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)
return;
if (active_variables && active_variables->find(var.self) == end(*active_variables))
return;
// In SPIR-V 1.4 and up, every global must be present in the entry point interface list,
// not just IO variables.
bool active_in_entry_point = true;
if (ir.get_spirv_version() < 0x10400)
{
if (var.storage == StorageClassInput || var.storage == StorageClassOutput)
active_in_entry_point = interface_variable_exists_in_entry_point(var.self);
}
else
active_in_entry_point = interface_variable_exists_in_entry_point(var.self);
if (!active_in_entry_point)
return;
bool is_builtin = is_builtin_variable(var);
if (is_builtin)
{
if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
return;
auto &list = var.storage == StorageClassInput ? res.builtin_inputs : res.builtin_outputs;
BuiltInResource resource;
if (has_decoration(type.self, DecorationBlock))
{
resource.resource = { var.self, var.basetype, type.self,
get_remapped_declared_block_name(var.self, false) };
for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
{
resource.value_type_id = type.member_types[i];
resource.builtin = BuiltIn(get_member_decoration(type.self, i, DecorationBuiltIn));
list.push_back(resource);
}
}
else
{
bool strip_array =
!has_decoration(var.self, DecorationPatch) && (
get_execution_model() == ExecutionModelTessellationControl ||
(get_execution_model() == ExecutionModelTessellationEvaluation &&
var.storage == StorageClassInput));
resource.resource = { var.self, var.basetype, type.self, get_name(var.self) };
if (strip_array && !type.array.empty())
resource.value_type_id = get_variable_data_type(var).parent_type;
else
resource.value_type_id = get_variable_data_type_id(var);
assert(resource.value_type_id);
resource.builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
list.push_back(std::move(resource));
}
return;
}
// Input
if (var.storage == StorageClassInput)
{
if (has_decoration(type.self, DecorationBlock))
{
res.stage_inputs.push_back(
{ var.self, var.basetype, type.self,
get_remapped_declared_block_name(var.self, false) });
}
else
res.stage_inputs.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// Subpass inputs
else if (var.storage == StorageClassUniformConstant && type.image.dim == DimSubpassData)
{
res.subpass_inputs.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// Outputs
else if (var.storage == StorageClassOutput)
{
if (has_decoration(type.self, DecorationBlock))
{
res.stage_outputs.push_back(
{ var.self, var.basetype, type.self, get_remapped_declared_block_name(var.self, false) });
}
else
res.stage_outputs.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// UBOs
else if (type.storage == StorageClassUniform && has_decoration(type.self, DecorationBlock))
{
res.uniform_buffers.push_back(
{ var.self, var.basetype, type.self, get_remapped_declared_block_name(var.self, false) });
}
// Old way to declare SSBOs.
else if (type.storage == StorageClassUniform && has_decoration(type.self, DecorationBufferBlock))
{
res.storage_buffers.push_back(
{ var.self, var.basetype, type.self, get_remapped_declared_block_name(var.self, ssbo_instance_name) });
}
// Modern way to declare SSBOs.
else if (type.storage == StorageClassStorageBuffer)
{
res.storage_buffers.push_back(
{ var.self, var.basetype, type.self, get_remapped_declared_block_name(var.self, ssbo_instance_name) });
}
// 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, get_name(var.self) });
}
else if (type.storage == StorageClassShaderRecordBufferKHR)
{
res.shader_record_buffers.push_back({ var.self, var.basetype, type.self, get_remapped_declared_block_name(var.self, ssbo_instance_name) });
}
// Atomic counters
else if (type.storage == StorageClassAtomicCounter)
{
res.atomic_counters.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
else if (type.storage == StorageClassUniformConstant)
{
if (type.basetype == SPIRType::Image)
{
// Images
if (type.image.sampled == 2)
{
res.storage_images.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// Separate images
else if (type.image.sampled == 1)
{
res.separate_images.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
}
// Separate samplers
else if (type.basetype == SPIRType::Sampler)
{
res.separate_samplers.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// Textures
else if (type.basetype == SPIRType::SampledImage)
{
res.sampled_images.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
// Acceleration structures
else if (type.basetype == SPIRType::AccelerationStructure)
{
res.acceleration_structures.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
else
{
res.gl_plain_uniforms.push_back({ var.self, var.basetype, type.self, get_name(var.self) });
}
}
});
return res;
}
bool Compiler::type_is_top_level_block(const SPIRType &type) const
{
if (type.basetype != SPIRType::Struct)
return false;
return has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock);
}
bool Compiler::type_is_block_like(const SPIRType &type) const
{
if (type_is_top_level_block(type))
return true;
if (type.basetype == SPIRType::Struct)
{
// Block-like types may have Offset decorations.
for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
if (has_member_decoration(type.self, i, DecorationOffset))
return true;
}
return false;
}
void Compiler::parse_fixup()
{
// Figure out specialization constants for work group sizes.
for (auto id_ : ir.ids_for_constant_or_variable)
{
auto &id = ir.ids[id_];
if (id.get_type() == TypeConstant)
{
auto &c = id.get<SPIRConstant>();
if (has_decoration(c.self, DecorationBuiltIn) &&
BuiltIn(get_decoration(c.self, DecorationBuiltIn)) == BuiltInWorkgroupSize)
{
// In current SPIR-V, there can be just one constant like this.
// All entry points will receive the constant value.
// WorkgroupSize take precedence over LocalSizeId.
for (auto &entry : ir.entry_points)
{
entry.second.workgroup_size.constant = c.self;
entry.second.workgroup_size.x = c.scalar(0, 0);
entry.second.workgroup_size.y = c.scalar(0, 1);
entry.second.workgroup_size.z = c.scalar(0, 2);
}
}
}
else if (id.get_type() == TypeVariable)
{
auto &var = id.get<SPIRVariable>();
if (var.storage == StorageClassPrivate || var.storage == StorageClassWorkgroup ||
var.storage == StorageClassTaskPayloadWorkgroupEXT ||
var.storage == StorageClassOutput)
{
global_variables.push_back(var.self);
}
if (variable_storage_is_aliased(var))
aliased_variables.push_back(var.self);
}
}
}
void Compiler::update_name_cache(unordered_set<string> &cache_primary, const unordered_set<string> &cache_secondary,
string &name)
{
if (name.empty())
return;
const auto find_name = [&](const string &n) -> bool {
if (cache_primary.find(n) != end(cache_primary))
return true;
if (&cache_primary != &cache_secondary)
if (cache_secondary.find(n) != end(cache_secondary))
return true;
return false;
};
const auto insert_name = [&](const string &n) { cache_primary.insert(n); };
if (!find_name(name))
{
insert_name(name);
return;
}
uint32_t counter = 0;
auto tmpname = name;
bool use_linked_underscore = true;
if (tmpname == "_")
{
// We cannot just append numbers, as we will end up creating internally reserved names.
// Make it like _0_<counter> instead.
tmpname += "0";
}
else if (tmpname.back() == '_')
{
// The last_character is an underscore, so we don't need to link in underscore.
// This would violate double underscore rules.
use_linked_underscore = false;
}
// If there is a collision (very rare),
// keep tacking on extra identifier until it's unique.
do
{
counter++;
name = tmpname + (use_linked_underscore ? "_" : "") + convert_to_string(counter);
} while (find_name(name));
insert_name(name);
}
void Compiler::update_name_cache(unordered_set<string> &cache, string &name)
{
update_name_cache(cache, cache, name);
}
void Compiler::set_name(ID id, const std::string &name)
{
ir.set_name(id, name);
}
const SPIRType &Compiler::get_type(TypeID id) const
{
return get<SPIRType>(id);
}
const SPIRType &Compiler::get_type_from_variable(VariableID id) const
{
return get<SPIRType>(get<SPIRVariable>(id).basetype);
}
uint32_t Compiler::get_pointee_type_id(uint32_t type_id) const
{
auto *p_type = &get<SPIRType>(type_id);
if (p_type->pointer)
{
assert(p_type->parent_type);
type_id = p_type->parent_type;
}
return type_id;
}
const SPIRType &Compiler::get_pointee_type(const SPIRType &type) const
{
auto *p_type = &type;
if (p_type->pointer)
{
assert(p_type->parent_type);
p_type = &get<SPIRType>(p_type->parent_type);
}
return *p_type;
}
const SPIRType &Compiler::get_pointee_type(uint32_t type_id) const
{
return get_pointee_type(get<SPIRType>(type_id));
}
uint32_t Compiler::get_variable_data_type_id(const SPIRVariable &var) const
{
if (var.phi_variable || var.storage == spv::StorageClass::StorageClassAtomicCounter)
return var.basetype;
return get_pointee_type_id(var.basetype);
}
SPIRType &Compiler::get_variable_data_type(const SPIRVariable &var)
{
return get<SPIRType>(get_variable_data_type_id(var));
}
const SPIRType &Compiler::get_variable_data_type(const SPIRVariable &var) const
{
return get<SPIRType>(get_variable_data_type_id(var));
}
SPIRType &Compiler::get_variable_element_type(const SPIRVariable &var)
{
SPIRType *type = &get_variable_data_type(var);
if (is_array(*type))
type = &get<SPIRType>(type->parent_type);
return *type;
}
const SPIRType &Compiler::get_variable_element_type(const SPIRVariable &var) const
{
const SPIRType *type = &get_variable_data_type(var);
if (is_array(*type))
type = &get<SPIRType>(type->parent_type);
return *type;
}
bool Compiler::is_sampled_image_type(const SPIRType &type)
{
return (type.basetype == SPIRType::Image || type.basetype == SPIRType::SampledImage) && type.image.sampled == 1 &&
type.image.dim != DimBuffer;
}
void Compiler::set_member_decoration_string(TypeID id, uint32_t index, spv::Decoration decoration,
const std::string &argument)
{
ir.set_member_decoration_string(id, index, decoration, argument);
}
void Compiler::set_member_decoration(TypeID id, uint32_t index, Decoration decoration, uint32_t argument)
{
ir.set_member_decoration(id, index, decoration, argument);
}
void Compiler::set_member_name(TypeID id, uint32_t index, const std::string &name)
{
ir.set_member_name(id, index, name);
}
const std::string &Compiler::get_member_name(TypeID id, uint32_t index) const
{
return ir.get_member_name(id, index);
}
void Compiler::set_qualified_name(uint32_t id, const string &name)
{
ir.meta[id].decoration.qualified_alias = name;
}
void Compiler::set_member_qualified_name(uint32_t type_id, uint32_t index, const std::string &name)
{
ir.meta[type_id].members.resize(max(ir.meta[type_id].members.size(), size_t(index) + 1));
ir.meta[type_id].members[index].qualified_alias = name;
}
const string &Compiler::get_member_qualified_name(TypeID type_id, uint32_t index) const
{
auto *m = ir.find_meta(type_id);
if (m && index < m->members.size())
return m->members[index].qualified_alias;
else
return ir.get_empty_string();
}
uint32_t Compiler::get_member_decoration(TypeID id, uint32_t index, Decoration decoration) const
{
return ir.get_member_decoration(id, index, decoration);
}
const Bitset &Compiler::get_member_decoration_bitset(TypeID id, uint32_t index) const
{
return ir.get_member_decoration_bitset(id, index);
}
bool Compiler::has_member_decoration(TypeID id, uint32_t index, Decoration decoration) const
{
return ir.has_member_decoration(id, index, decoration);
}
void Compiler::unset_member_decoration(TypeID id, uint32_t index, Decoration decoration)
{
ir.unset_member_decoration(id, index, decoration);
}
void Compiler::set_decoration_string(ID id, spv::Decoration decoration, const std::string &argument)
{
ir.set_decoration_string(id, decoration, argument);
}
void Compiler::set_decoration(ID id, Decoration decoration, uint32_t argument)
{
ir.set_decoration(id, decoration, argument);
}
void Compiler::set_extended_decoration(uint32_t id, ExtendedDecorations decoration, uint32_t value)
{
auto &dec = ir.meta[id].decoration;
dec.extended.flags.set(decoration);
dec.extended.values[decoration] = value;
}
void Compiler::set_extended_member_decoration(uint32_t type, uint32_t index, ExtendedDecorations decoration,
uint32_t value)
{
ir.meta[type].members.resize(max(ir.meta[type].members.size(), size_t(index) + 1));
auto &dec = ir.meta[type].members[index];
dec.extended.flags.set(decoration);
dec.extended.values[decoration] = value;
}
static uint32_t get_default_extended_decoration(ExtendedDecorations decoration)
{
switch (decoration)
{
case SPIRVCrossDecorationResourceIndexPrimary:
case SPIRVCrossDecorationResourceIndexSecondary:
case SPIRVCrossDecorationResourceIndexTertiary:
case SPIRVCrossDecorationResourceIndexQuaternary:
case SPIRVCrossDecorationInterfaceMemberIndex:
return ~(0u);
default:
return 0;
}
}
uint32_t Compiler::get_extended_decoration(uint32_t id, ExtendedDecorations decoration) const
{
auto *m = ir.find_meta(id);
if (!m)
return 0;
auto &dec = m->decoration;
if (!dec.extended.flags.get(decoration))
return get_default_extended_decoration(decoration);
return dec.extended.values[decoration];
}
uint32_t Compiler::get_extended_member_decoration(uint32_t type, uint32_t index, ExtendedDecorations decoration) const
{
auto *m = ir.find_meta(type);
if (!m)
return 0;
if (index >= m->members.size())
return 0;
auto &dec = m->members[index];
if (!dec.extended.flags.get(decoration))
return get_default_extended_decoration(decoration);
return dec.extended.values[decoration];
}
bool Compiler::has_extended_decoration(uint32_t id, ExtendedDecorations decoration) const
{
auto *m = ir.find_meta(id);
if (!m)
return false;
auto &dec = m->decoration;
return dec.extended.flags.get(decoration);
}
bool Compiler::has_extended_member_decoration(uint32_t type, uint32_t index, ExtendedDecorations decoration) const
{
auto *m = ir.find_meta(type);
if (!m)
return false;
if (index >= m->members.size())
return false;
auto &dec = m->members[index];
return dec.extended.flags.get(decoration);
}
void Compiler::unset_extended_decoration(uint32_t id, ExtendedDecorations decoration)
{
auto &dec = ir.meta[id].decoration;
dec.extended.flags.clear(decoration);
dec.extended.values[decoration] = 0;
}
void Compiler::unset_extended_member_decoration(uint32_t type, uint32_t index, ExtendedDecorations decoration)
{
ir.meta[type].members.resize(max(ir.meta[type].members.size(), size_t(index) + 1));
auto &dec = ir.meta[type].members[index];
dec.extended.flags.clear(decoration);
dec.extended.values[decoration] = 0;
}
StorageClass Compiler::get_storage_class(VariableID id) const
{
return get<SPIRVariable>(id).storage;
}
const std::string &Compiler::get_name(ID id) const
{
return ir.get_name(id);
}
const std::string Compiler::get_fallback_name(ID id) const
{
return join("_", id);
}
const std::string Compiler::get_block_fallback_name(VariableID id) const
{
auto &var = get<SPIRVariable>(id);
if (get_name(id).empty())
return join("_", get<SPIRType>(var.basetype).self, "_", id);
else
return get_name(id);
}
const Bitset &Compiler::get_decoration_bitset(ID id) const
{
return ir.get_decoration_bitset(id);
}
bool Compiler::has_decoration(ID id, Decoration decoration) const
{
return ir.has_decoration(id, decoration);
}
const string &Compiler::get_decoration_string(ID id, Decoration decoration) const
{
return ir.get_decoration_string(id, decoration);
}
const string &Compiler::get_member_decoration_string(TypeID id, uint32_t index, Decoration decoration) const
{
return ir.get_member_decoration_string(id, index, decoration);
}
uint32_t Compiler::get_decoration(ID id, Decoration decoration) const
{
return ir.get_decoration(id, decoration);
}
void Compiler::unset_decoration(ID id, Decoration decoration)
{
ir.unset_decoration(id, decoration);
}
bool Compiler::get_binary_offset_for_decoration(VariableID id, spv::Decoration decoration, uint32_t &word_offset) const
{
auto *m = ir.find_meta(id);
if (!m)
return false;
auto &word_offsets = m->decoration_word_offset;
auto itr = word_offsets.find(decoration);
if (itr == end(word_offsets))
return false;
word_offset = itr->second;
return true;
}
bool Compiler::block_is_noop(const SPIRBlock &block) const
{
if (block.terminator != SPIRBlock::Direct)
return false;
auto &child = get<SPIRBlock>(block.next_block);
// If this block participates in PHI, the block isn't really noop.
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;
// Verify all instructions have no semantic impact.
for (auto &i : block.ops)
{
auto op = static_cast<Op>(i.op);
switch (op)
{
// Non-Semantic instructions.
case OpLine:
case OpNoLine:
break;
case OpExtInst:
{
auto *ops = stream(i);
auto ext = get<SPIRExtension>(ops[2]).ext;
bool ext_is_nonsemantic_only =
ext == SPIRExtension::NonSemanticShaderDebugInfo ||
ext == SPIRExtension::SPV_debug_info ||
ext == SPIRExtension::NonSemanticGeneric;
if (!ext_is_nonsemantic_only)
return false;
break;
}
default:
return false;
}
}
return true;
}
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 || method == SPIRBlock::MergeToSelectContinueForLoop)
{
// 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.
const auto *false_block = maybe_get<SPIRBlock>(block.false_block);
const auto *true_block = maybe_get<SPIRBlock>(block.true_block);
const auto *merge_block = maybe_get<SPIRBlock>(block.merge_block);
bool false_block_is_merge = block.false_block == block.merge_block ||
(false_block && merge_block && execution_is_noop(*false_block, *merge_block));
bool true_block_is_merge = block.true_block == block.merge_block ||
(true_block && merge_block && execution_is_noop(*true_block, *merge_block));
bool positive_candidate =
block.true_block != block.merge_block && block.true_block != block.self && false_block_is_merge;
bool negative_candidate =
block.false_block != block.merge_block && block.false_block != block.self && true_block_is_merge;
bool ret = block.terminator == SPIRBlock::Select && block.merge == SPIRBlock::MergeLoop &&
(positive_candidate || negative_candidate);
if (ret && positive_candidate && method == SPIRBlock::MergeToSelectContinueForLoop)
ret = block.true_block == block.continue_block;
else if (ret && negative_candidate && method == SPIRBlock::MergeToSelectContinueForLoop)
ret = block.false_block == block.continue_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_is_noop(block);
if (!ret)
return false;
auto &child = get<SPIRBlock>(block.next_block);
const auto *false_block = maybe_get<SPIRBlock>(child.false_block);
const auto *true_block = maybe_get<SPIRBlock>(child.true_block);
const auto *merge_block = maybe_get<SPIRBlock>(block.merge_block);
bool false_block_is_merge = child.false_block == block.merge_block ||
(false_block && merge_block && execution_is_noop(*false_block, *merge_block));
bool true_block_is_merge = child.true_block == block.merge_block ||
(true_block && merge_block && execution_is_noop(*true_block, *merge_block));
bool positive_candidate =
child.true_block != block.merge_block && child.true_block != block.self && false_block_is_merge;
bool negative_candidate =
child.false_block != block.merge_block && child.false_block != block.self && true_block_is_merge;
ret = child.terminator == SPIRBlock::Select && child.merge == SPIRBlock::MergeNone &&
(positive_candidate || negative_candidate);
if (ret)
{
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::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 (!block_is_noop(*start))
return false;
auto &next = get<SPIRBlock>(start->next_block);
start = &next;
}
}
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;
}
}
bool Compiler::execution_is_direct_branch(const SPIRBlock &from, const SPIRBlock &to) const
{
return from.terminator == SPIRBlock::Direct && from.merge == SPIRBlock::MergeNone && from.next_block == to.self;
}
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;
if (block.loop_dominator == BlockID(SPIRBlock::NoDominator))
{
// Continue block is never reached from CFG.
return SPIRBlock::ComplexLoop;
}
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
{
const auto *false_block = maybe_get<SPIRBlock>(block.false_block);
const auto *true_block = maybe_get<SPIRBlock>(block.true_block);
const auto *merge_block = maybe_get<SPIRBlock>(dominator.merge_block);
// If we need to flush Phi in this block, we cannot have a DoWhile loop.
bool flush_phi_to_false = false_block && flush_phi_required(block.self, block.false_block);
bool flush_phi_to_true = true_block && flush_phi_required(block.self, block.true_block);
if (flush_phi_to_false || flush_phi_to_true)
return SPIRBlock::ComplexLoop;
bool positive_do_while = block.true_block == dominator.self &&
(block.false_block == dominator.merge_block ||
(false_block && merge_block && execution_is_noop(*false_block, *merge_block)));
bool negative_do_while = block.false_block == dominator.self &&
(block.true_block == dominator.merge_block ||
(true_block && merge_block && execution_is_noop(*true_block, *merge_block)));
if (block.merge == SPIRBlock::MergeNone && block.terminator == SPIRBlock::Select &&
(positive_do_while || negative_do_while))
{
return SPIRBlock::DoWhileLoop;
}
else
return SPIRBlock::ComplexLoop;
}
}
const SmallVector<SPIRBlock::Case> &Compiler::get_case_list(const SPIRBlock &block) const
{
uint32_t width = 0;
// First we check if we can get the type directly from the block.condition
// since it can be a SPIRConstant or a SPIRVariable.
if (const auto *constant = maybe_get<SPIRConstant>(block.condition))
{
const auto &type = get<SPIRType>(constant->constant_type);
width = type.width;
}
else if (const auto *var = maybe_get<SPIRVariable>(block.condition))
{
const auto &type = get<SPIRType>(var->basetype);
width = type.width;
}
else if (const auto *undef = maybe_get<SPIRUndef>(block.condition))
{
const auto &type = get<SPIRType>(undef->basetype);
width = type.width;
}
else
{
auto search = ir.load_type_width.find(block.condition);
if (search == ir.load_type_width.end())
{
SPIRV_CROSS_THROW("Use of undeclared variable on a switch statement.");
}
width = search->second;
}
if (width > 32)
return block.cases_64bit;
return block.cases_32bit;
}
bool Compiler::traverse_all_reachable_opcodes(const SPIRBlock &block, OpcodeHandler &handler) const
{
handler.set_current_block(block);
handler.rearm_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;
handler.rearm_current_block(block);
}
}
}
if (!handler.handle_terminator(block))
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
{
auto *type_meta = ir.find_meta(type.self);
if (type_meta)
{
// Decoration must be set in valid SPIR-V, otherwise throw.
auto &dec = type_meta->members[index];
if (dec.decoration_flags.get(DecorationOffset))
return dec.offset;
else
SPIRV_CROSS_THROW("Struct member does not have Offset set.");
}
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
{
auto *type_meta = ir.find_meta(type.member_types[index]);
if (type_meta)
{
// Decoration must be set in valid SPIR-V, otherwise throw.
// ArrayStride is part of the array type not OpMemberDecorate.
auto &dec = type_meta->decoration;
if (dec.decoration_flags.get(DecorationArrayStride))
return dec.array_stride;
else
SPIRV_CROSS_THROW("Struct member does not have ArrayStride set.");
}
else
SPIRV_CROSS_THROW("Struct member does not have ArrayStride set.");
}
uint32_t Compiler::type_struct_member_matrix_stride(const SPIRType &type, uint32_t index) const
{
auto *type_meta = ir.find_meta(type.self);
if (type_meta)
{
// Decoration must be set in valid SPIR-V, otherwise throw.
// MatrixStride is part of OpMemberDecorate.
auto &dec = type_meta->members[index];
if (dec.decoration_flags.get(DecorationMatrixStride))
return dec.matrix_stride;
else
SPIRV_CROSS_THROW("Struct member does not have MatrixStride set.");
}
else
SPIRV_CROSS_THROW("Struct member does not have MatrixStride set.");
}
size_t Compiler::get_declared_struct_size(const SPIRType &type) const
{
if (type.member_types.empty())
SPIRV_CROSS_THROW("Declared struct in block cannot be empty.");
// Offsets can be declared out of order, so we need to deduce the actual size
// based on last member instead.
uint32_t member_index = 0;
size_t highest_offset = 0;
for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
{
size_t offset = type_struct_member_offset(type, i);
if (offset > highest_offset)
{
highest_offset = offset;
member_index = i;
}
}
size_t size = get_declared_struct_member_size(type, member_index);
return highest_offset + size;
}
size_t Compiler::get_declared_struct_size_runtime_array(const SPIRType &type, size_t array_size) const
{
if (type.member_types.empty())
SPIRV_CROSS_THROW("Declared struct in block cannot be empty.");
size_t size = get_declared_struct_size(type);
auto &last_type = get<SPIRType>(type.member_types.back());
if (!last_type.array.empty() && last_type.array_size_literal[0] && last_type.array[0] == 0) // Runtime array
size += array_size * type_struct_member_array_stride(type, uint32_t(type.member_types.size() - 1));
return size;
}
uint32_t Compiler::evaluate_spec_constant_u32(const SPIRConstantOp &spec) const
{
auto &result_type = get<SPIRType>(spec.basetype);
if (result_type.basetype != SPIRType::UInt && result_type.basetype != SPIRType::Int &&
result_type.basetype != SPIRType::Boolean)
{
SPIRV_CROSS_THROW(
"Only 32-bit integers and booleans are currently supported when evaluating specialization constants.\n");
}
if (!is_scalar(result_type))
SPIRV_CROSS_THROW("Spec constant evaluation must be a scalar.\n");
uint32_t value = 0;
const auto eval_u32 = [&](uint32_t id) -> uint32_t {
auto &type = expression_type(id);
if (type.basetype != SPIRType::UInt && type.basetype != SPIRType::Int && type.basetype != SPIRType::Boolean)
{
SPIRV_CROSS_THROW("Only 32-bit integers and booleans are currently supported when evaluating "
"specialization constants.\n");
}
if (!is_scalar(type))
SPIRV_CROSS_THROW("Spec constant evaluation must be a scalar.\n");
if (const auto *c = this->maybe_get<SPIRConstant>(id))
return c->scalar();
else
return evaluate_spec_constant_u32(this->get<SPIRConstantOp>(id));
};
#define binary_spec_op(op, binary_op) \
case Op##op: \
value = eval_u32(spec.arguments[0]) binary_op eval_u32(spec.arguments[1]); \
break
#define binary_spec_op_cast(op, binary_op, type) \
case Op##op: \
value = uint32_t(type(eval_u32(spec.arguments[0])) binary_op type(eval_u32(spec.arguments[1]))); \
break
// Support the basic opcodes which are typically used when computing array sizes.
switch (spec.opcode)
{
binary_spec_op(IAdd, +);
binary_spec_op(ISub, -);
binary_spec_op(IMul, *);
binary_spec_op(BitwiseAnd, &);
binary_spec_op(BitwiseOr, |);
binary_spec_op(BitwiseXor, ^);
binary_spec_op(LogicalAnd, &);
binary_spec_op(LogicalOr, |);
binary_spec_op(ShiftLeftLogical, <<);
binary_spec_op(ShiftRightLogical, >>);
binary_spec_op_cast(ShiftRightArithmetic, >>, int32_t);
binary_spec_op(LogicalEqual, ==);
binary_spec_op(LogicalNotEqual, !=);
binary_spec_op(IEqual, ==);
binary_spec_op(INotEqual, !=);
binary_spec_op(ULessThan, <);
binary_spec_op(ULessThanEqual, <=);
binary_spec_op(UGreaterThan, >);
binary_spec_op(UGreaterThanEqual, >=);
binary_spec_op_cast(SLessThan, <, int32_t);
binary_spec_op_cast(SLessThanEqual, <=, int32_t);
binary_spec_op_cast(SGreaterThan, >, int32_t);
binary_spec_op_cast(SGreaterThanEqual, >=, int32_t);
#undef binary_spec_op
#undef binary_spec_op_cast
case OpLogicalNot:
value = uint32_t(!eval_u32(spec.arguments[0]));
break;
case OpNot:
value = ~eval_u32(spec.arguments[0]);
break;
case OpSNegate:
value = uint32_t(-int32_t(eval_u32(spec.arguments[0])));
break;
case OpSelect:
value = eval_u32(spec.arguments[0]) ? eval_u32(spec.arguments[1]) : eval_u32(spec.arguments[2]);
break;
case OpUMod:
{
uint32_t a = eval_u32(spec.arguments[0]);
uint32_t b = eval_u32(spec.arguments[1]);
if (b == 0)
SPIRV_CROSS_THROW("Undefined behavior in UMod, b == 0.\n");
value = a % b;
break;
}
case OpSRem:
{
auto a = int32_t(eval_u32(spec.arguments[0]));
auto b = int32_t(eval_u32(spec.arguments[1]));
if (b == 0)
SPIRV_CROSS_THROW("Undefined behavior in SRem, b == 0.\n");
value = a % b;
break;
}
case OpSMod:
{
auto a = int32_t(eval_u32(spec.arguments[0]));
auto b = int32_t(eval_u32(spec.arguments[1]));
if (b == 0)
SPIRV_CROSS_THROW("Undefined behavior in SMod, b == 0.\n");
auto v = a % b;
// Makes sure we match the sign of b, not a.
if ((b < 0 && v > 0) || (b > 0 && v < 0))
v += b;
value = v;
break;
}
case OpUDiv:
{
uint32_t a = eval_u32(spec.arguments[0]);
uint32_t b = eval_u32(spec.arguments[1]);
if (b == 0)
SPIRV_CROSS_THROW("Undefined behavior in UDiv, b == 0.\n");
value = a / b;
break;
}
case OpSDiv:
{
auto a = int32_t(eval_u32(spec.arguments[0]));
auto b = int32_t(eval_u32(spec.arguments[1]));
if (b == 0)
SPIRV_CROSS_THROW("Undefined behavior in SDiv, b == 0.\n");
value = a / b;
break;
}
default:
SPIRV_CROSS_THROW("Unsupported spec constant opcode for evaluation.\n");
}
return value;
}
uint32_t Compiler::evaluate_constant_u32(uint32_t id) const
{
if (const auto *c = maybe_get<SPIRConstant>(id))
return c->scalar();
else
return evaluate_spec_constant_u32(get<SPIRConstantOp>(id));
}
size_t Compiler::get_declared_struct_member_size(const SPIRType &struct_type, uint32_t index) const
{
if (struct_type.member_types.empty())
SPIRV_CROSS_THROW("Declared struct in block cannot be empty.");
auto &flags = get_member_decoration_bitset(struct_type.self, index);
auto &type = get<SPIRType>(struct_type.member_types[index]);
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.");
default:
break;
}
if (type.pointer && type.storage == StorageClassPhysicalStorageBuffer)
{
// Check if this is a top-level pointer type, and not an array of pointers.
if (type.pointer_depth > get<SPIRType>(type.parent_type).pointer_depth)
return 8;
}
if (!type.array.empty())
{
// For arrays, we can use ArrayStride to get an easy check.
bool array_size_literal = type.array_size_literal.back();
uint32_t array_size = array_size_literal ? type.array.back() : evaluate_constant_u32(type.array.back());
return type_struct_member_array_stride(struct_type, index) * array_size;
}
else if (type.basetype == SPIRType::Struct)
{
return get_declared_struct_size(type);
}
else
{
unsigned vecsize = type.vecsize;
unsigned columns = type.columns;
// Vectors.
if (columns == 1)
{
size_t component_size = type.width / 8;
return vecsize * component_size;
}
else
{
uint32_t matrix_stride = type_struct_member_matrix_stride(struct_type, index);
// Per SPIR-V spec, matrices must be tightly packed and aligned up for vec3 accesses.
if (flags.get(DecorationRowMajor))
return matrix_stride * vecsize;
else if (flags.get(DecorationColMajor))
return matrix_stride * columns;
else
SPIRV_CROSS_THROW("Either row-major or column-major must be declared for matrices.");
}
}
}
bool Compiler::BufferAccessHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
if (opcode != OpAccessChain && opcode != OpInBoundsAccessChain && opcode != OpPtrAccessChain)
return true;
bool ptr_chain = (opcode == OpPtrAccessChain);
// Invalid SPIR-V.
if (length < (ptr_chain ? 5u : 4u))
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[ptr_chain ? 4 : 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;
}
SmallVector<BufferRange> Compiler::get_active_buffer_ranges(VariableID id) const
{
SmallVector<BufferRange> ranges;
BufferAccessHandler handler(*this, ranges, id);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
return ranges;
}
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;
}
const Bitset &Compiler::get_execution_mode_bitset() 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.set(mode);
switch (mode)
{
case ExecutionModeLocalSize:
execution.workgroup_size.x = arg0;
execution.workgroup_size.y = arg1;
execution.workgroup_size.z = arg2;
break;
case ExecutionModeLocalSizeId:
execution.workgroup_size.id_x = arg0;
execution.workgroup_size.id_y = arg1;
execution.workgroup_size.id_z = arg2;
break;
case ExecutionModeInvocations:
execution.invocations = arg0;
break;
case ExecutionModeOutputVertices:
execution.output_vertices = arg0;
break;
case ExecutionModeOutputPrimitivesEXT:
execution.output_primitives = arg0;
break;
default:
break;
}
}
void Compiler::unset_execution_mode(ExecutionMode mode)
{
auto &execution = get_entry_point();
execution.flags.clear(mode);
}
uint32_t Compiler::get_work_group_size_specialization_constants(SpecializationConstant &x, SpecializationConstant &y,
SpecializationConstant &z) const
{
auto &execution = get_entry_point();
x = { 0, 0 };
y = { 0, 0 };
z = { 0, 0 };
// WorkgroupSize builtin takes precedence over LocalSize / LocalSizeId.
if (execution.workgroup_size.constant != 0)
{
auto &c = get<SPIRConstant>(execution.workgroup_size.constant);
if (c.m.c[0].id[0] != ID(0))
{
x.id = c.m.c[0].id[0];
x.constant_id = get_decoration(c.m.c[0].id[0], DecorationSpecId);
}
if (c.m.c[0].id[1] != ID(0))
{
y.id = c.m.c[0].id[1];
y.constant_id = get_decoration(c.m.c[0].id[1], DecorationSpecId);
}
if (c.m.c[0].id[2] != ID(0))
{
z.id = c.m.c[0].id[2];
z.constant_id = get_decoration(c.m.c[0].id[2], DecorationSpecId);
}
}
else if (execution.flags.get(ExecutionModeLocalSizeId))
{
auto &cx = get<SPIRConstant>(execution.workgroup_size.id_x);
if (cx.specialization)
{
x.id = execution.workgroup_size.id_x;
x.constant_id = get_decoration(execution.workgroup_size.id_x, DecorationSpecId);
}
auto &cy = get<SPIRConstant>(execution.workgroup_size.id_y);
if (cy.specialization)
{
y.id = execution.workgroup_size.id_y;
y.constant_id = get_decoration(execution.workgroup_size.id_y, DecorationSpecId);
}
auto &cz = get<SPIRConstant>(execution.workgroup_size.id_z);
if (cz.specialization)
{
z.id = execution.workgroup_size.id_z;
z.constant_id = get_decoration(execution.workgroup_size.id_z, DecorationSpecId);
}
}
return execution.workgroup_size.constant;
}
uint32_t Compiler::get_execution_mode_argument(spv::ExecutionMode mode, uint32_t index) const
{
auto &execution = get_entry_point();
switch (mode)
{
case ExecutionModeLocalSizeId:
if (execution.flags.get(ExecutionModeLocalSizeId))
{
switch (index)
{
case 0:
return execution.workgroup_size.id_x;
case 1:
return execution.workgroup_size.id_y;
case 2:
return execution.workgroup_size.id_z;
default:
return 0;
}
}
else
return 0;
case ExecutionModeLocalSize:
switch (index)
{
case 0:
if (execution.flags.get(ExecutionModeLocalSizeId) && execution.workgroup_size.id_x != 0)
return get<SPIRConstant>(execution.workgroup_size.id_x).scalar();
else
return execution.workgroup_size.x;
case 1:
if (execution.flags.get(ExecutionModeLocalSizeId) && execution.workgroup_size.id_y != 0)
return get<SPIRConstant>(execution.workgroup_size.id_y).scalar();
else
return execution.workgroup_size.y;
case 2:
if (execution.flags.get(ExecutionModeLocalSizeId) && execution.workgroup_size.id_z != 0)
return get<SPIRConstant>(execution.workgroup_size.id_z).scalar();
else
return execution.workgroup_size.z;
default:
return 0;
}
case ExecutionModeInvocations:
return execution.invocations;
case ExecutionModeOutputVertices:
return execution.output_vertices;
case ExecutionModeOutputPrimitivesEXT:
return execution.output_primitives;
default:
return 0;
}
}
ExecutionModel Compiler::get_execution_model() const
{
auto &execution = get_entry_point();
return execution.model;
}
bool Compiler::is_tessellation_shader(ExecutionModel model)
{
return model == ExecutionModelTessellationControl || model == ExecutionModelTessellationEvaluation;
}
bool Compiler::is_vertex_like_shader() const
{
auto model = get_execution_model();
return model == ExecutionModelVertex || model == ExecutionModelGeometry ||
model == ExecutionModelTessellationControl || model == ExecutionModelTessellationEvaluation;
}
bool Compiler::is_tessellation_shader() const
{
return is_tessellation_shader(get_execution_model());
}
bool Compiler::is_tessellating_triangles() const
{
return get_execution_mode_bitset().get(ExecutionModeTriangles);
}
void Compiler::set_remapped_variable_state(VariableID id, bool remap_enable)
{
get<SPIRVariable>(id).remapped_variable = remap_enable;
}
bool Compiler::get_remapped_variable_state(VariableID id) const
{
return get<SPIRVariable>(id).remapped_variable;
}
void Compiler::set_subpass_input_remapped_components(VariableID id, uint32_t components)
{
get<SPIRVariable>(id).remapped_components = components;
}
uint32_t Compiler::get_subpass_input_remapped_components(VariableID id) const
{
return get<SPIRVariable>(id).remapped_components;
}
void Compiler::add_implied_read_expression(SPIRExpression &e, uint32_t source)
{
auto itr = find(begin(e.implied_read_expressions), end(e.implied_read_expressions), ID(source));
if (itr == end(e.implied_read_expressions))
e.implied_read_expressions.push_back(source);
}
void Compiler::add_implied_read_expression(SPIRAccessChain &e, uint32_t source)
{
auto itr = find(begin(e.implied_read_expressions), end(e.implied_read_expressions), ID(source));
if (itr == end(e.implied_read_expressions))
e.implied_read_expressions.push_back(source);
}
void Compiler::add_active_interface_variable(uint32_t var_id)
{
active_interface_variables.insert(var_id);
// In SPIR-V 1.4 and up we must also track the interface variable in the entry point.
if (ir.get_spirv_version() >= 0x10400)
{
auto &vars = get_entry_point().interface_variables;
if (find(begin(vars), end(vars), VariableID(var_id)) == end(vars))
vars.push_back(var_id);
}
}
void Compiler::inherit_expression_dependencies(uint32_t dst, uint32_t source_expression)
{
// Don't inherit any expression dependencies if the expression in dst
// is not a forwarded temporary.
if (forwarded_temporaries.find(dst) == end(forwarded_temporaries) ||
forced_temporaries.find(dst) != end(forced_temporaries))
{
return;
}
auto &e = get<SPIRExpression>(dst);
auto *phi = maybe_get<SPIRVariable>(source_expression);
if (phi && phi->phi_variable)
{
// We have used a phi variable, which can change at the end of the block,
// so make sure we take a dependency on this phi variable.
phi->dependees.push_back(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.
sort(begin(e_deps), end(e_deps));
e_deps.erase(unique(begin(e_deps), end(e_deps)), end(e_deps));
}
SmallVector<EntryPoint> Compiler::get_entry_points_and_stages() const
{
SmallVector<EntryPoint> entries;
for (auto &entry : ir.entry_points)
entries.push_back({ entry.second.orig_name, entry.second.model });
return entries;
}
void Compiler::rename_entry_point(const std::string &old_name, const std::string &new_name, spv::ExecutionModel model)
{
auto &entry = get_entry_point(old_name, model);
entry.orig_name = new_name;
entry.name = new_name;
}
void Compiler::set_entry_point(const std::string &name, spv::ExecutionModel model)
{
auto &entry = get_entry_point(name, model);
ir.default_entry_point = entry.self;
}
SPIREntryPoint &Compiler::get_first_entry_point(const std::string &name)
{
auto itr = find_if(
begin(ir.entry_points), end(ir.entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool { return entry.second.orig_name == name; });
if (itr == end(ir.entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
const SPIREntryPoint &Compiler::get_first_entry_point(const std::string &name) const
{
auto itr = find_if(
begin(ir.entry_points), end(ir.entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool { return entry.second.orig_name == name; });
if (itr == end(ir.entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
SPIREntryPoint &Compiler::get_entry_point(const std::string &name, ExecutionModel model)
{
auto itr = find_if(begin(ir.entry_points), end(ir.entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool {
return entry.second.orig_name == name && entry.second.model == model;
});
if (itr == end(ir.entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
const SPIREntryPoint &Compiler::get_entry_point(const std::string &name, ExecutionModel model) const
{
auto itr = find_if(begin(ir.entry_points), end(ir.entry_points),
[&](const std::pair<uint32_t, SPIREntryPoint> &entry) -> bool {
return entry.second.orig_name == name && entry.second.model == model;
});
if (itr == end(ir.entry_points))
SPIRV_CROSS_THROW("Entry point does not exist.");
return itr->second;
}
const string &Compiler::get_cleansed_entry_point_name(const std::string &name, ExecutionModel model) const
{
return get_entry_point(name, model).name;
}
const SPIREntryPoint &Compiler::get_entry_point() const
{
return ir.entry_points.find(ir.default_entry_point)->second;
}
SPIREntryPoint &Compiler::get_entry_point()
{
return ir.entry_points.find(ir.default_entry_point)->second;
}
bool Compiler::interface_variable_exists_in_entry_point(uint32_t id) const
{
auto &var = get<SPIRVariable>(id);
if (ir.get_spirv_version() < 0x10400)
{
if (var.storage != StorageClassInput && var.storage != StorageClassOutput &&
var.storage != StorageClassUniformConstant)
SPIRV_CROSS_THROW("Only Input, Output variables and Uniform constants 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 (ir.entry_points.size() <= 1)
return true;
}
// In SPIR-V 1.4 and later, all global resource variables must be present.
auto &execution = get_entry_point();
return find(begin(execution.interface_variables), end(execution.interface_variables), VariableID(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(std::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;
// 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)
{
VariableID image_id = param.global_image ? param.image_id : VariableID(args[param.image_id]);
VariableID sampler_id = param.global_sampler ? param.sampler_id : VariableID(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, 0, image_id, sampler_id, param.depth);
}
}
return true;
}
void Compiler::CombinedImageSamplerHandler::register_combined_image_sampler(SPIRFunction &caller,
VariableID combined_module_id,
VariableID image_id, VariableID sampler_id,
bool depth)
{
// 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, depth,
};
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.ir.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, OpTypeSampledImage);
auto &ptr_type = compiler.set<SPIRType>(ptr_type_id, OpTypePointer);
type = base;
type.self = type_id;
type.basetype = SPIRType::SampledImage;
type.pointer = false;
type.storage = StorageClassGeneric;
type.image.depth = depth;
ptr_type = type;
ptr_type.pointer = true;
ptr_type.storage = StorageClassUniformConstant;
ptr_type.parent_type = type_id;
// Build new variable.
compiler.set<SPIRVariable>(combined_id, ptr_type_id, StorageClassFunction, 0);
// Inherit RelaxedPrecision.
// If any of OpSampledImage, underlying image or sampler are marked, inherit the decoration.
bool relaxed_precision =
compiler.has_decoration(sampler_id, DecorationRelaxedPrecision) ||
compiler.has_decoration(image_id, DecorationRelaxedPrecision) ||
(combined_module_id && compiler.has_decoration(combined_module_id, DecorationRelaxedPrecision));
if (relaxed_precision)
compiler.set_decoration(combined_id, 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, true });
}
}
bool Compiler::DummySamplerForCombinedImageHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
if (need_dummy_sampler)
{
// No need to traverse further, we know the result.
return false;
}
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 && type.image.dim != DimBuffer;
// If not separate image, don't bother.
if (!separate_image)
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);
break;
}
case OpImageFetch:
case OpImageQuerySizeLod:
case OpImageQuerySize:
case OpImageQueryLevels:
case OpImageQuerySamples:
{
// If we are fetching or querying LOD from a plain OpTypeImage, we must pre-combine with our dummy sampler.
auto *var = compiler.maybe_get_backing_variable(args[2]);
if (var)
{
auto &type = compiler.get<SPIRType>(var->basetype);
if (type.basetype == SPIRType::Image && type.image.sampled == 1 && type.image.dim != DimBuffer)
need_dummy_sampler = true;
}
break;
}
case OpInBoundsAccessChain:
case OpAccessChain:
case OpPtrAccessChain:
{
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 && type.image.dim != DimBuffer;
if (!separate_image)
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);
// Other backends might use SPIRAccessChain for this later.
compiler.ir.ids[id].set_allow_type_rewrite();
break;
}
default:
break;
}
return true;
}
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.
bool is_fetch = false;
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:
case OpPtrAccessChain:
{
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.
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 (separate_sampler)
SPIRV_CROSS_THROW(
"Attempting to use arrays or structs of separate samplers. This is not possible to statically "
"remap to plain GLSL.");
if (separate_image)
{
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 OpImageFetch:
case OpImageQuerySizeLod:
case OpImageQuerySize:
case OpImageQueryLevels:
case OpImageQuerySamples:
{
// If we are fetching from a plain OpTypeImage or querying LOD, we must pre-combine with our dummy sampler.
auto *var = compiler.maybe_get_backing_variable(args[2]);
if (!var)
return true;
auto &type = compiler.get<SPIRType>(var->basetype);
if (type.basetype == SPIRType::Image && type.image.sampled == 1 && type.image.dim != DimBuffer)
{
if (compiler.dummy_sampler_id == 0)
SPIRV_CROSS_THROW("texelFetch without sampler was found, but no dummy sampler has been created with "
"build_dummy_sampler_for_combined_images().");
// Do it outside.
is_fetch = true;
break;
}
return true;
}
case OpSampledImage:
// Do it outside.
break;
default:
return true;
}
// 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 = is_fetch ? compiler.dummy_sampler_id : args[3];
auto *sampler = compiler.maybe_get_backing_variable(sampler_id);
if (sampler)
sampler_id = sampler->self;
uint32_t combined_id = args[1];
auto &combined_type = compiler.get<SPIRType>(args[0]);
register_combined_image_sampler(callee, combined_id, image_id, sampler_id, combined_type.image.depth);
}
}
// 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.
VariableID image_id = remap_parameter(args[2]);
VariableID sampler_id = is_fetch ? compiler.dummy_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))
{
uint32_t sampled_type;
uint32_t combined_module_id;
if (is_fetch)
{
// Have to invent the sampled image type.
sampled_type = compiler.ir.increase_bound_by(1);
auto &type = compiler.set<SPIRType>(sampled_type, OpTypeSampledImage);
type = compiler.expression_type(args[2]);
type.self = sampled_type;
type.basetype = SPIRType::SampledImage;
type.image.depth = false;
combined_module_id = 0;
}
else
{
sampled_type = args[0];
combined_module_id = args[1];
}
auto id = compiler.ir.increase_bound_by(2);
auto type_id = id + 0;
auto combined_id = id + 1;
// 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, OpTypePointer);
auto &base = compiler.get<SPIRType>(sampled_type);
type = base;
type.pointer = true;
type.storage = StorageClassUniformConstant;
type.parent_type = type_id;
// Build new variable.
compiler.set<SPIRVariable>(combined_id, type_id, StorageClassUniformConstant, 0);
// Inherit RelaxedPrecision (and potentially other useful flags if deemed relevant).
// If any of OpSampledImage, underlying image or sampler are marked, inherit the decoration.
bool relaxed_precision =
(sampler_id && compiler.has_decoration(sampler_id, DecorationRelaxedPrecision)) ||
(image_id && compiler.has_decoration(image_id, DecorationRelaxedPrecision)) ||
(combined_module_id && compiler.has_decoration(combined_module_id, DecorationRelaxedPrecision));
if (relaxed_precision)
compiler.set_decoration(combined_id, DecorationRelaxedPrecision);
// Propagate the array type for the original image as well.
auto *var = compiler.maybe_get_backing_variable(image_id);
if (var)
{
auto &parent_type = compiler.get<SPIRType>(var->basetype);
type.array = parent_type.array;
type.array_size_literal = parent_type.array_size_literal;
}
compiler.combined_image_samplers.push_back({ combined_id, image_id, sampler_id });
}
return true;
}
VariableID Compiler::build_dummy_sampler_for_combined_images()
{
DummySamplerForCombinedImageHandler handler(*this);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
if (handler.need_dummy_sampler)
{
uint32_t offset = ir.increase_bound_by(3);
auto type_id = offset + 0;
auto ptr_type_id = offset + 1;
auto var_id = offset + 2;
auto &sampler = set<SPIRType>(type_id, OpTypeSampler);
sampler.basetype = SPIRType::Sampler;
auto &ptr_sampler = set<SPIRType>(ptr_type_id, OpTypePointer);
ptr_sampler = sampler;
ptr_sampler.self = type_id;
ptr_sampler.storage = StorageClassUniformConstant;
ptr_sampler.pointer = true;
ptr_sampler.parent_type = type_id;
set<SPIRVariable>(var_id, ptr_type_id, StorageClassUniformConstant, 0);
set_name(var_id, "SPIRV_Cross_DummySampler");
dummy_sampler_id = var_id;
return var_id;
}
else
return 0;
}
void Compiler::build_combined_image_samplers()
{
ir.for_each_typed_id<SPIRFunction>([&](uint32_t, SPIRFunction &func) {
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>(ir.default_entry_point), handler);
}
SmallVector<SpecializationConstant> Compiler::get_specialization_constants() const
{
SmallVector<SpecializationConstant> spec_consts;
ir.for_each_typed_id<SPIRConstant>([&](uint32_t, const SPIRConstant &c) {
if (c.specialization && has_decoration(c.self, DecorationSpecId))
spec_consts.push_back({ c.self, get_decoration(c.self, DecorationSpecId) });
});
return spec_consts;
}
SPIRConstant &Compiler::get_constant(ConstantID id)
{
return get<SPIRConstant>(id);
}
const SPIRConstant &Compiler::get_constant(ConstantID id) const
{
return get<SPIRConstant>(id);
}
static bool exists_unaccessed_path_to_return(const CFG &cfg, uint32_t block, const unordered_set<uint32_t> &blocks,
unordered_set<uint32_t> &visit_cache)
{
// This block accesses the variable.
if (blocks.find(block) != end(blocks))
return false;
// We are at the end of the CFG.
if (cfg.get_succeeding_edges(block).empty())
return true;
// If any of our successors have a path to the end, there exists a path from block.
for (auto &succ : cfg.get_succeeding_edges(block))
{
if (visit_cache.count(succ) == 0)
{
if (exists_unaccessed_path_to_return(cfg, succ, blocks, visit_cache))
return true;
visit_cache.insert(succ);
}
}
return false;
}
void Compiler::analyze_parameter_preservation(
SPIRFunction &entry, const CFG &cfg, const unordered_map<uint32_t, unordered_set<uint32_t>> &variable_to_blocks,
const unordered_map<uint32_t, unordered_set<uint32_t>> &complete_write_blocks)
{
for (auto &arg : entry.arguments)
{
// Non-pointers are always inputs.
auto &type = get<SPIRType>(arg.type);
if (!type.pointer)
continue;
// Opaque argument types are always in
bool potential_preserve;
switch (type.basetype)
{
case SPIRType::Sampler:
case SPIRType::Image:
case SPIRType::SampledImage:
case SPIRType::AtomicCounter:
potential_preserve = false;
break;
default:
potential_preserve = true;
break;
}
if (!potential_preserve)
continue;
auto itr = variable_to_blocks.find(arg.id);
if (itr == end(variable_to_blocks))
{
// Variable is never accessed.
continue;
}
// We have accessed a variable, but there was no complete writes to that variable.
// We deduce that we must preserve the argument.
itr = complete_write_blocks.find(arg.id);
if (itr == end(complete_write_blocks))
{
arg.read_count++;
continue;
}
// If there is a path through the CFG where no block completely writes to the variable, the variable will be in an undefined state
// when the function returns. We therefore need to implicitly preserve the variable in case there are writers in the function.
// Major case here is if a function is
// void foo(int &var) { if (cond) var = 10; }
// Using read/write counts, we will think it's just an out variable, but it really needs to be inout,
// because if we don't write anything whatever we put into the function must return back to the caller.
unordered_set<uint32_t> visit_cache;
if (exists_unaccessed_path_to_return(cfg, entry.entry_block, itr->second, visit_cache))
arg.read_count++;
}
}
Compiler::AnalyzeVariableScopeAccessHandler::AnalyzeVariableScopeAccessHandler(Compiler &compiler_,
SPIRFunction &entry_)
: compiler(compiler_)
, entry(entry_)
{
}
bool Compiler::AnalyzeVariableScopeAccessHandler::follow_function_call(const SPIRFunction &)
{
// Only analyze within this function.
return false;
}
void Compiler::AnalyzeVariableScopeAccessHandler::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);
// Phi variables are also accessed in our target branch block.
accessed_variables_to_block[phi.function_variable].insert(next.self);
notify_variable_access(phi.local_variable, block.self);
}
}
};
switch (block.terminator)
{
case SPIRBlock::Direct:
notify_variable_access(block.condition, block.self);
test_phi(block.next_block);
break;
case SPIRBlock::Select:
notify_variable_access(block.condition, block.self);
test_phi(block.true_block);
test_phi(block.false_block);
break;
case SPIRBlock::MultiSelect:
{
notify_variable_access(block.condition, block.self);
auto &cases = compiler.get_case_list(block);
for (auto &target : cases)
test_phi(target.block);
if (block.default_block)
test_phi(block.default_block);
break;
}
default:
break;
}
}
void Compiler::AnalyzeVariableScopeAccessHandler::notify_variable_access(uint32_t id, uint32_t block)
{
if (id == 0)
return;
// Access chains used in multiple blocks mean hoisting all the variables used to construct the access chain as not all backends can use pointers.
auto itr = rvalue_forward_children.find(id);
if (itr != end(rvalue_forward_children))
for (auto child_id : itr->second)
notify_variable_access(child_id, block);
if (id_is_phi_variable(id))
accessed_variables_to_block[id].insert(block);
else if (id_is_potential_temporary(id))
accessed_temporaries_to_block[id].insert(block);
}
bool Compiler::AnalyzeVariableScopeAccessHandler::id_is_phi_variable(uint32_t id) const
{
if (id >= compiler.get_current_id_bound())
return false;
auto *var = compiler.maybe_get<SPIRVariable>(id);
return var && var->phi_variable;
}
bool Compiler::AnalyzeVariableScopeAccessHandler::id_is_potential_temporary(uint32_t id) const
{
if (id >= compiler.get_current_id_bound())
return false;
// Temporaries are not created before we start emitting code.
return compiler.ir.ids[id].empty() || (compiler.ir.ids[id].get_type() == TypeExpression);
}
bool Compiler::AnalyzeVariableScopeAccessHandler::handle_terminator(const SPIRBlock &block)
{
switch (block.terminator)
{
case SPIRBlock::Return:
if (block.return_value)
notify_variable_access(block.return_value, block.self);
break;
case SPIRBlock::Select:
case SPIRBlock::MultiSelect:
notify_variable_access(block.condition, block.self);
break;
default:
break;
}
return true;
}
bool Compiler::AnalyzeVariableScopeAccessHandler::handle(spv::Op op, const uint32_t *args, uint32_t length)
{
// Keep track of the types of temporaries, so we can hoist them out as necessary.
uint32_t result_type = 0, result_id = 0;
if (compiler.instruction_to_result_type(result_type, result_id, op, args, length))
{
// For some opcodes, we will need to override the result id.
// If we need to hoist the temporary, the temporary type is the input, not the result.
if (op == OpConvertUToAccelerationStructureKHR)
{
auto itr = result_id_to_type.find(args[2]);
if (itr != result_id_to_type.end())
result_type = itr->second;
}
result_id_to_type[result_id] = result_type;
}
switch (op)
{
case OpStore:
{
if (length < 2)
return false;
ID ptr = args[0];
auto *var = compiler.maybe_get_backing_variable(ptr);
// If we store through an access chain, we have a partial write.
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
if (var->self == ptr)
complete_write_variables_to_block[var->self].insert(current_block->self);
else
partial_write_variables_to_block[var->self].insert(current_block->self);
}
// args[0] might be an access chain we have to track use of.
notify_variable_access(args[0], current_block->self);
// Might try to store a Phi variable here.
notify_variable_access(args[1], current_block->self);
break;
}
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
{
if (length < 3)
return false;
// Access chains used in multiple blocks mean hoisting all the variables used to construct the access chain as not all backends can use pointers.
uint32_t ptr = args[2];
auto *var = compiler.maybe_get<SPIRVariable>(ptr);
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
rvalue_forward_children[args[1]].insert(var->self);
}
// args[2] might be another access chain we have to track use of.
for (uint32_t i = 2; i < length; i++)
{
notify_variable_access(args[i], current_block->self);
rvalue_forward_children[args[1]].insert(args[i]);
}
// Also keep track of the access chain pointer itself.
// In exceptionally rare cases, we can end up with a case where
// the access chain is generated in the loop body, but is consumed in continue block.
// This means we need complex loop workarounds, and we must detect this via CFG analysis.
notify_variable_access(args[1], current_block->self);
// The result of an access chain is a fixed expression and is not really considered a temporary.
auto &e = compiler.set<SPIRExpression>(args[1], "", args[0], true);
auto *backing_variable = compiler.maybe_get_backing_variable(ptr);
e.loaded_from = backing_variable ? VariableID(backing_variable->self) : VariableID(0);
// Other backends might use SPIRAccessChain for this later.
compiler.ir.ids[args[1]].set_allow_type_rewrite();
access_chain_expressions.insert(args[1]);
break;
}
case OpCopyMemory:
{
if (length < 2)
return false;
ID lhs = args[0];
ID rhs = args[1];
auto *var = compiler.maybe_get_backing_variable(lhs);
// If we store through an access chain, we have a partial write.
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
if (var->self == lhs)
complete_write_variables_to_block[var->self].insert(current_block->self);
else
partial_write_variables_to_block[var->self].insert(current_block->self);
}
// args[0:1] might be access chains we have to track use of.
for (uint32_t i = 0; i < 2; i++)
notify_variable_access(args[i], current_block->self);
var = compiler.maybe_get_backing_variable(rhs);
if (var)
accessed_variables_to_block[var->self].insert(current_block->self);
break;
}
case OpCopyObject:
{
// OpCopyObject copies the underlying non-pointer type,
// so any temp variable should be declared using the underlying type.
// If the type is a pointer, get its base type and overwrite the result type mapping.
auto &type = compiler.get<SPIRType>(result_type);
if (type.pointer)
result_id_to_type[result_id] = type.parent_type;
if (length < 3)
return false;
auto *var = compiler.maybe_get_backing_variable(args[2]);
if (var)
accessed_variables_to_block[var->self].insert(current_block->self);
// Might be an access chain which we have to keep track of.
notify_variable_access(args[1], current_block->self);
if (access_chain_expressions.count(args[2]))
access_chain_expressions.insert(args[1]);
// Might try to copy a Phi variable here.
notify_variable_access(args[2], 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)
accessed_variables_to_block[var->self].insert(current_block->self);
// Loaded value is a temporary.
notify_variable_access(args[1], current_block->self);
// Might be an access chain we have to track use of.
notify_variable_access(args[2], current_block->self);
// If we're loading an opaque type we cannot lower it to a temporary,
// we must defer access of args[2] until it's used.
auto &type = compiler.get<SPIRType>(args[0]);
if (compiler.type_is_opaque_value(type))
rvalue_forward_children[args[1]].insert(args[2]);
break;
}
case OpFunctionCall:
{
if (length < 3)
return false;
// Return value may be a temporary.
if (compiler.get_type(args[0]).basetype != SPIRType::Void)
notify_variable_access(args[1], current_block->self);
length -= 3;
args += 3;
for (uint32_t i = 0; i < length; i++)
{
auto *var = compiler.maybe_get_backing_variable(args[i]);
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
// Assume we can get partial writes to this variable.
partial_write_variables_to_block[var->self].insert(current_block->self);
}
// Cannot easily prove if argument we pass to a function is completely written.
// Usually, functions write to a dummy variable,
// which is then copied to in full to the real argument.
// Might try to copy a Phi variable here.
notify_variable_access(args[i], current_block->self);
}
break;
}
case OpSelect:
{
// In case of variable pointers, we might access a variable here.
// We cannot prove anything about these accesses however.
for (uint32_t i = 1; i < length; i++)
{
if (i >= 3)
{
auto *var = compiler.maybe_get_backing_variable(args[i]);
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
// Assume we can get partial writes to this variable.
partial_write_variables_to_block[var->self].insert(current_block->self);
}
}
// Might try to copy a Phi variable here.
notify_variable_access(args[i], current_block->self);
}
break;
}
case OpExtInst:
{
for (uint32_t i = 4; i < length; i++)
notify_variable_access(args[i], current_block->self);
notify_variable_access(args[1], current_block->self);
uint32_t extension_set = args[2];
if (compiler.get<SPIRExtension>(extension_set).ext == SPIRExtension::GLSL)
{
auto op_450 = static_cast<GLSLstd450>(args[3]);
switch (op_450)
{
case GLSLstd450Modf:
case GLSLstd450Frexp:
{
uint32_t ptr = args[5];
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var)
{
accessed_variables_to_block[var->self].insert(current_block->self);
if (var->self == ptr)
complete_write_variables_to_block[var->self].insert(current_block->self);
else
partial_write_variables_to_block[var->self].insert(current_block->self);
}
break;
}
default:
break;
}
}
break;
}
case OpArrayLength:
// Only result is a temporary.
notify_variable_access(args[1], current_block->self);
break;
case OpLine:
case OpNoLine:
// Uses literals, but cannot be a phi variable or temporary, so ignore.
break;
// Atomics shouldn't be able to access function-local variables.
// Some GLSL builtins access a pointer.
case OpCompositeInsert:
case OpVectorShuffle:
// Specialize for opcode which contains literals.
for (uint32_t i = 1; i < 4; i++)
notify_variable_access(args[i], current_block->self);
break;
case OpCompositeExtract:
// Specialize for opcode which contains literals.
for (uint32_t i = 1; i < 3; i++)
notify_variable_access(args[i], current_block->self);
break;
case OpImageWrite:
for (uint32_t i = 0; i < length; i++)
{
// Argument 3 is a literal.
if (i != 3)
notify_variable_access(args[i], current_block->self);
}
break;
case OpImageSampleImplicitLod:
case OpImageSampleExplicitLod:
case OpImageSparseSampleImplicitLod:
case OpImageSparseSampleExplicitLod:
case OpImageSampleProjImplicitLod:
case OpImageSampleProjExplicitLod:
case OpImageSparseSampleProjImplicitLod:
case OpImageSparseSampleProjExplicitLod:
case OpImageFetch:
case OpImageSparseFetch:
case OpImageRead:
case OpImageSparseRead:
for (uint32_t i = 1; i < length; i++)
{
// Argument 4 is a literal.
if (i != 4)
notify_variable_access(args[i], current_block->self);
}
break;
case OpImageSampleDrefImplicitLod:
case OpImageSampleDrefExplicitLod:
case OpImageSparseSampleDrefImplicitLod:
case OpImageSparseSampleDrefExplicitLod:
case OpImageSampleProjDrefImplicitLod:
case OpImageSampleProjDrefExplicitLod:
case OpImageSparseSampleProjDrefImplicitLod:
case OpImageSparseSampleProjDrefExplicitLod:
case OpImageGather:
case OpImageSparseGather:
case OpImageDrefGather:
case OpImageSparseDrefGather:
for (uint32_t i = 1; i < length; i++)
{
// Argument 5 is a literal.
if (i != 5)
notify_variable_access(args[i], current_block->self);
}
break;
default:
{
// Rather dirty way of figuring out where Phi variables are used.
// As long as only IDs are used, we can scan through instructions and try to find any evidence that
// the ID of a variable has been used.
// There are potential false positives here where a literal is used in-place of an ID,
// but worst case, it does not affect the correctness of the compile.
// Exhaustive analysis would be better here, but it's not worth it for now.
for (uint32_t i = 0; i < length; i++)
notify_variable_access(args[i], current_block->self);
break;
}
}
return true;
}
Compiler::StaticExpressionAccessHandler::StaticExpressionAccessHandler(Compiler &compiler_, uint32_t variable_id_)
: compiler(compiler_)
, variable_id(variable_id_)
{
}
bool Compiler::StaticExpressionAccessHandler::follow_function_call(const SPIRFunction &)
{
return false;
}
bool Compiler::StaticExpressionAccessHandler::handle(spv::Op op, const uint32_t *args, uint32_t length)
{
switch (op)
{
case OpStore:
if (length < 2)
return false;
if (args[0] == variable_id)
{
static_expression = args[1];
write_count++;
}
break;
case OpLoad:
if (length < 3)
return false;
if (args[2] == variable_id && static_expression == 0) // Tried to read from variable before it was initialized.
return false;
break;
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
if (length < 3)
return false;
if (args[2] == variable_id) // If we try to access chain our candidate variable before we store to it, bail.
return false;
break;
default:
break;
}
return true;
}
void Compiler::find_function_local_luts(SPIRFunction &entry, const AnalyzeVariableScopeAccessHandler &handler,
bool single_function)
{
auto &cfg = *function_cfgs.find(entry.self)->second;
// For each variable which is statically accessed.
for (auto &accessed_var : handler.accessed_variables_to_block)
{
auto &blocks = accessed_var.second;
auto &var = get<SPIRVariable>(accessed_var.first);
auto &type = expression_type(accessed_var.first);
// First check if there are writes to the variable. Later, if there are none, we'll
// reconsider it as globally accessed LUT.
if (!var.is_written_to)
{
var.is_written_to = handler.complete_write_variables_to_block.count(var.self) != 0 ||
handler.partial_write_variables_to_block.count(var.self) != 0;
}
// Only consider function local variables here.
// If we only have a single function in our CFG, private storage is also fine,
// since it behaves like a function local variable.
bool allow_lut = var.storage == StorageClassFunction || (single_function && var.storage == StorageClassPrivate);
if (!allow_lut)
continue;
// We cannot be a phi variable.
if (var.phi_variable)
continue;
// Only consider arrays here.
if (type.array.empty())
continue;
// If the variable has an initializer, make sure it is a constant expression.
uint32_t static_constant_expression = 0;
if (var.initializer)
{
if (ir.ids[var.initializer].get_type() != TypeConstant)
continue;
static_constant_expression = var.initializer;
// There can be no stores to this variable, we have now proved we have a LUT.
if (var.is_written_to)
continue;
}
else
{
// We can have one, and only one write to the variable, and that write needs to be a constant.
// No partial writes allowed.
if (handler.partial_write_variables_to_block.count(var.self) != 0)
continue;
auto itr = handler.complete_write_variables_to_block.find(var.self);
// No writes?
if (itr == end(handler.complete_write_variables_to_block))
continue;
// We write to the variable in more than one block.
auto &write_blocks = itr->second;
if (write_blocks.size() != 1)
continue;
// The write needs to happen in the dominating block.
DominatorBuilder builder(cfg);
for (auto &block : blocks)
builder.add_block(block);
uint32_t dominator = builder.get_dominator();
// The complete write happened in a branch or similar, cannot deduce static expression.
if (write_blocks.count(dominator) == 0)
continue;
// Find the static expression for this variable.
StaticExpressionAccessHandler static_expression_handler(*this, var.self);
traverse_all_reachable_opcodes(get<SPIRBlock>(dominator), static_expression_handler);
// We want one, and exactly one write
if (static_expression_handler.write_count != 1 || static_expression_handler.static_expression == 0)
continue;
// Is it a constant expression?
if (ir.ids[static_expression_handler.static_expression].get_type() != TypeConstant)
continue;
// We found a LUT!
static_constant_expression = static_expression_handler.static_expression;
}
get<SPIRConstant>(static_constant_expression).is_used_as_lut = true;
var.static_expression = static_constant_expression;
var.statically_assigned = true;
var.remapped_variable = true;
}
}
void Compiler::analyze_variable_scope(SPIRFunction &entry, AnalyzeVariableScopeAccessHandler &handler)
{
// First, we map out all variable access within a function.
// Essentially a map of block -> { variables accessed in the basic block }
traverse_all_reachable_opcodes(entry, handler);
auto &cfg = *function_cfgs.find(entry.self)->second;
// Analyze if there are parameters which need to be implicitly preserved with an "in" qualifier.
analyze_parameter_preservation(entry, cfg, handler.accessed_variables_to_block,
handler.complete_write_variables_to_block);
unordered_map<uint32_t, uint32_t> potential_loop_variables;
// Find the loop dominator block for each block.
for (auto &block_id : entry.blocks)
{
auto &block = get<SPIRBlock>(block_id);
auto itr = ir.continue_block_to_loop_header.find(block_id);
if (itr != end(ir.continue_block_to_loop_header) && itr->second != block_id)
{
// Continue block might be unreachable in the CFG, but we still like to know the loop dominator.
// Edge case is when continue block is also the loop header, don't set the dominator in this case.
block.loop_dominator = itr->second;
}
else
{
uint32_t loop_dominator = cfg.find_loop_dominator(block_id);
if (loop_dominator != block_id)
block.loop_dominator = loop_dominator;
else
block.loop_dominator = SPIRBlock::NoDominator;
}
}
// For each variable which is statically accessed.
for (auto &var : handler.accessed_variables_to_block)
{
// Only deal with variables which are considered local variables in this function.
if (find(begin(entry.local_variables), end(entry.local_variables), VariableID(var.first)) ==
end(entry.local_variables))
continue;
DominatorBuilder builder(cfg);
auto &blocks = var.second;
auto &type = expression_type(var.first);
BlockID potential_continue_block = 0;
// 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))
{
// Potentially awkward case to check for.
// We might have a variable inside a loop, which is touched by the continue block,
// but is not actually a loop variable.
// The continue block is dominated by the inner part of the loop, which does not make sense in high-level
// language output because it will be declared before the body,
// so we will have to lift the dominator up to the relevant loop header instead.
builder.add_block(ir.continue_block_to_loop_header[block]);
// Arrays or structs cannot be loop variables.
if (type.vecsize == 1 && type.columns == 1 && type.basetype != SPIRType::Struct && type.array.empty())
{
// The variable is used in multiple continue blocks, this is not a loop
// candidate, signal that by setting block to -1u.
if (potential_continue_block == 0)
potential_continue_block = block;
else
potential_continue_block = ~(0u);
}
}
builder.add_block(block);
}
builder.lift_continue_block_dominator();
// Add it to a per-block list of variables.
BlockID dominating_block = builder.get_dominator();
if (dominating_block && potential_continue_block != 0 && potential_continue_block != ~0u)
{
auto &inner_block = get<SPIRBlock>(dominating_block);
BlockID merge_candidate = 0;
// Analyze the dominator. If it lives in a different loop scope than the candidate continue
// block, reject the loop variable candidate.
if (inner_block.merge == SPIRBlock::MergeLoop)
merge_candidate = inner_block.merge_block;
else if (inner_block.loop_dominator != SPIRBlock::NoDominator)
merge_candidate = get<SPIRBlock>(inner_block.loop_dominator).merge_block;
if (merge_candidate != 0 && cfg.is_reachable(merge_candidate))
{
// If the merge block has a higher post-visit order, we know that continue candidate
// cannot reach the merge block, and we have two separate scopes.
if (!cfg.is_reachable(potential_continue_block) ||
cfg.get_visit_order(merge_candidate) > cfg.get_visit_order(potential_continue_block))
{
potential_continue_block = 0;
}
}
}
if (potential_continue_block != 0 && potential_continue_block != ~0u)
potential_loop_variables[var.first] = potential_continue_block;
// For variables whose dominating block is inside a loop, there is a risk that these variables
// actually need to be preserved across loop iterations. We can express this by adding
// a "read" access to the loop header.
// In the dominating block, we must see an OpStore or equivalent as the first access of an OpVariable.
// Should that fail, we look for the outermost loop header and tack on an access there.
// Phi nodes cannot have this problem.
if (dominating_block)
{
auto &variable = get<SPIRVariable>(var.first);
if (!variable.phi_variable)
{
auto *block = &get<SPIRBlock>(dominating_block);
bool preserve = may_read_undefined_variable_in_block(*block, var.first);
if (preserve)
{
// Find the outermost loop scope.
while (block->loop_dominator != BlockID(SPIRBlock::NoDominator))
block = &get<SPIRBlock>(block->loop_dominator);
if (block->self != dominating_block)
{
builder.add_block(block->self);
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 = get<SPIRBlock>(dominating_block);
block.dominated_variables.push_back(var.first);
get<SPIRVariable>(var.first).dominator = dominating_block;
}
}
for (auto &var : handler.accessed_temporaries_to_block)
{
auto itr = handler.result_id_to_type.find(var.first);
if (itr == end(handler.result_id_to_type))
{
// We found a false positive ID being used, ignore.
// This should probably be an assert.
continue;
}
// There is no point in doing domination analysis for opaque types.
auto &type = get<SPIRType>(itr->second);
if (type_is_opaque_value(type))
continue;
DominatorBuilder builder(cfg);
bool force_temporary = false;
bool used_in_header_hoisted_continue_block = false;
// Figure out which block is dominating all accesses of those temporaries.
auto &blocks = var.second;
for (auto &block : blocks)
{
builder.add_block(block);
if (blocks.size() != 1 && is_continue(block))
{
// The risk here is that inner loop can dominate the continue block.
// Any temporary we access in the continue block must be declared before the loop.
// This is moot for complex loops however.
auto &loop_header_block = get<SPIRBlock>(ir.continue_block_to_loop_header[block]);
assert(loop_header_block.merge == SPIRBlock::MergeLoop);
builder.add_block(loop_header_block.self);
used_in_header_hoisted_continue_block = true;
}
}
uint32_t dominating_block = builder.get_dominator();
if (blocks.size() != 1 && is_single_block_loop(dominating_block))
{
// Awkward case, because the loop header is also the continue block,
// so hoisting to loop header does not help.
force_temporary = true;
}
if (dominating_block)
{
// If we touch a variable in the dominating block, this is the expected setup.
// SPIR-V normally mandates this, but we have extra cases for temporary use inside loops.
bool first_use_is_dominator = blocks.count(dominating_block) != 0;
if (!first_use_is_dominator || force_temporary)
{
if (handler.access_chain_expressions.count(var.first))
{
// Exceptionally rare case.
// We cannot declare temporaries of access chains (except on MSL perhaps with pointers).
// Rather than do that, we force the indexing expressions to be declared in the right scope by
// tracking their usage to that end. There is no temporary to hoist.
// However, we still need to observe declaration order of the access chain.
if (used_in_header_hoisted_continue_block)
{
// For this scenario, we used an access chain inside a continue block where we also registered an access to header block.
// This is a problem as we need to declare an access chain properly first with full definition.
// We cannot use temporaries for these expressions,
// so we must make sure the access chain is declared ahead of time.
// Force a complex for loop to deal with this.
// TODO: Out-of-order declaring for loops where continue blocks are emitted last might be another option.
auto &loop_header_block = get<SPIRBlock>(dominating_block);
assert(loop_header_block.merge == SPIRBlock::MergeLoop);
loop_header_block.complex_continue = true;
}
}
else
{
// This should be very rare, but if we try to declare a temporary inside a loop,
// and that temporary is used outside the loop as well (spirv-opt inliner likes this)
// we should actually emit the temporary outside the loop.
hoisted_temporaries.insert(var.first);
forced_temporaries.insert(var.first);
auto &block_temporaries = get<SPIRBlock>(dominating_block).declare_temporary;
block_temporaries.emplace_back(handler.result_id_to_type[var.first], var.first);
}
}
else if (blocks.size() > 1)
{
// Keep track of the temporary as we might have to declare this temporary.
// This can happen if the loop header dominates a temporary, but we have a complex fallback loop.
// In this case, the header is actually inside the for (;;) {} block, and we have problems.
// What we need to do is hoist the temporaries outside the for (;;) {} block in case the header block
// declares the temporary.
auto &block_temporaries = get<SPIRBlock>(dominating_block).potential_declare_temporary;
block_temporaries.emplace_back(handler.result_id_to_type[var.first], var.first);
}
}
}
unordered_set<uint32_t> seen_blocks;
// 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;
BlockID block = loop_variable.second;
// The variable was accessed in multiple continue blocks, ignore.
if (block == BlockID(~(0u)) || block == BlockID(0))
continue;
// Dead code.
if (dominator == ID(0))
continue;
BlockID header = 0;
// Find the loop header for this block if we are a continue block.
{
auto itr = ir.continue_block_to_loop_header.find(block);
if (itr != end(ir.continue_block_to_loop_header))
{
header = itr->second;
}
else if (get<SPIRBlock>(block).continue_block == block)
{
// Also check for self-referential continue block.
header = block;
}
}
assert(header);
auto &header_block = get<SPIRBlock>(header);
auto &blocks = handler.accessed_variables_to_block[loop_variable.first];
// If a loop variable is not used before the loop, it's probably not a loop variable.
bool has_accessed_variable = blocks.count(header) != 0;
// 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)
{
if (blocks.count(dominator) != 0)
has_accessed_variable = true;
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 || !has_accessed_variable)
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.
seen_blocks.clear();
cfg.walk_from(seen_blocks, header_block.merge_block, [&](uint32_t walk_block) -> bool {
// We found a block which accesses the variable outside the loop.
if (blocks.find(walk_block) != end(blocks))
static_loop_init = false;
return true;
});
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;
}
}
bool Compiler::may_read_undefined_variable_in_block(const SPIRBlock &block, uint32_t var)
{
for (auto &op : block.ops)
{
auto *ops = stream(op);
switch (op.op)
{
case OpStore:
case OpCopyMemory:
if (ops[0] == var)
return false;
break;
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
// Access chains are generally used to partially read and write. It's too hard to analyze
// if all constituents are written fully before continuing, so just assume it's preserved.
// This is the same as the parameter preservation analysis.
if (ops[2] == var)
return true;
break;
case OpSelect:
// Variable pointers.
// We might read before writing.
if (ops[3] == var || ops[4] == var)
return true;
break;
case OpPhi:
{
// Variable pointers.
// We might read before writing.
if (op.length < 2)
break;
uint32_t count = op.length - 2;
for (uint32_t i = 0; i < count; i += 2)
if (ops[i + 2] == var)
return true;
break;
}
case OpCopyObject:
case OpLoad:
if (ops[2] == var)
return true;
break;
case OpFunctionCall:
{
if (op.length < 3)
break;
// May read before writing.
uint32_t count = op.length - 3;
for (uint32_t i = 0; i < count; i++)
if (ops[i + 3] == var)
return true;
break;
}
default:
break;
}
}
// Not accessed somehow, at least not in a usual fashion.
// It's likely accessed in a branch, so assume we must preserve.
return true;
}
Bitset Compiler::get_buffer_block_flags(VariableID id) const
{
return ir.get_buffer_block_flags(get<SPIRVariable>(id));
}
bool Compiler::get_common_basic_type(const SPIRType &type, SPIRType::BaseType &base_type)
{
if (type.basetype == SPIRType::Struct)
{
base_type = SPIRType::Unknown;
for (auto &member_type : type.member_types)
{
SPIRType::BaseType member_base;
if (!get_common_basic_type(get<SPIRType>(member_type), member_base))
return false;
if (base_type == SPIRType::Unknown)
base_type = member_base;
else if (base_type != member_base)
return false;
}
return true;
}
else
{
base_type = type.basetype;
return true;
}
}
void Compiler::ActiveBuiltinHandler::handle_builtin(const SPIRType &type, BuiltIn builtin,
const Bitset &decoration_flags)
{
// If used, we will need to explicitly declare a new array size for these builtins.
if (builtin == BuiltInClipDistance)
{
if (!type.array_size_literal[0])
SPIRV_CROSS_THROW("Array size for ClipDistance must be a literal.");
uint32_t array_size = type.array[0];
if (array_size == 0)
SPIRV_CROSS_THROW("Array size for ClipDistance must not be unsized.");
compiler.clip_distance_count = array_size;
}
else if (builtin == BuiltInCullDistance)
{
if (!type.array_size_literal[0])
SPIRV_CROSS_THROW("Array size for CullDistance must be a literal.");
uint32_t array_size = type.array[0];
if (array_size == 0)
SPIRV_CROSS_THROW("Array size for CullDistance must not be unsized.");
compiler.cull_distance_count = array_size;
}
else if (builtin == BuiltInPosition)
{
if (decoration_flags.get(DecorationInvariant))
compiler.position_invariant = true;
}
}
void Compiler::ActiveBuiltinHandler::add_if_builtin(uint32_t id, bool allow_blocks)
{
// Only handle plain variables here.
// Builtins which are part of a block are handled in AccessChain.
// If allow_blocks is used however, this is to handle initializers of blocks,
// which implies that all members are written to.
auto *var = compiler.maybe_get<SPIRVariable>(id);
auto *m = compiler.ir.find_meta(id);
if (var && m)
{
auto &type = compiler.get<SPIRType>(var->basetype);
auto &decorations = m->decoration;
auto &flags = type.storage == StorageClassInput ?
compiler.active_input_builtins : compiler.active_output_builtins;
if (decorations.builtin)
{
flags.set(decorations.builtin_type);
handle_builtin(type, decorations.builtin_type, decorations.decoration_flags);
}
else if (allow_blocks && compiler.has_decoration(type.self, DecorationBlock))
{
uint32_t member_count = uint32_t(type.member_types.size());
for (uint32_t i = 0; i < member_count; i++)
{
if (compiler.has_member_decoration(type.self, i, DecorationBuiltIn))
{
auto &member_type = compiler.get<SPIRType>(type.member_types[i]);
BuiltIn builtin = BuiltIn(compiler.get_member_decoration(type.self, i, DecorationBuiltIn));
flags.set(builtin);
handle_builtin(member_type, builtin, compiler.get_member_decoration_bitset(type.self, i));
}
}
}
}
}
void Compiler::ActiveBuiltinHandler::add_if_builtin(uint32_t id)
{
add_if_builtin(id, false);
}
void Compiler::ActiveBuiltinHandler::add_if_builtin_or_block(uint32_t id)
{
add_if_builtin(id, true);
}
bool Compiler::ActiveBuiltinHandler::handle(spv::Op opcode, const uint32_t *args, uint32_t length)
{
switch (opcode)
{
case OpStore:
if (length < 1)
return false;
add_if_builtin(args[0]);
break;
case OpCopyMemory:
if (length < 2)
return false;
add_if_builtin(args[0]);
add_if_builtin(args[1]);
break;
case OpCopyObject:
case OpLoad:
if (length < 3)
return false;
add_if_builtin(args[2]);
break;
case OpSelect:
if (length < 5)
return false;
add_if_builtin(args[3]);
add_if_builtin(args[4]);
break;
case OpPhi:
{
if (length < 2)
return false;
uint32_t count = length - 2;
args += 2;
for (uint32_t i = 0; i < count; i += 2)
add_if_builtin(args[i]);
break;
}
case OpFunctionCall:
{
if (length < 3)
return false;
uint32_t count = length - 3;
args += 3;
for (uint32_t i = 0; i < count; i++)
add_if_builtin(args[i]);
break;
}
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
{
if (length < 4)
return false;
// Only consider global variables, cannot consider variables in functions yet, or other
// access chains as they have not been created yet.
auto *var = compiler.maybe_get<SPIRVariable>(args[2]);
if (!var)
break;
// Required if we access chain into builtins like gl_GlobalInvocationID.
add_if_builtin(args[2]);
// Start traversing type hierarchy at the proper non-pointer types.
auto *type = &compiler.get_variable_data_type(*var);
auto &flags =
var->storage == StorageClassInput ? compiler.active_input_builtins : compiler.active_output_builtins;
uint32_t count = length - 3;
args += 3;
for (uint32_t i = 0; i < count; i++)
{
// Pointers
// PtrAccessChain functions more like a pointer offset. Type remains the same.
if (opcode == OpPtrAccessChain && i == 0)
continue;
// Arrays
if (!type->array.empty())
{
type = &compiler.get<SPIRType>(type->parent_type);
}
// Structs
else if (type->basetype == SPIRType::Struct)
{
uint32_t index = compiler.get<SPIRConstant>(args[i]).scalar();
if (index < uint32_t(compiler.ir.meta[type->self].members.size()))
{
auto &decorations = compiler.ir.meta[type->self].members[index];
if (decorations.builtin)
{
flags.set(decorations.builtin_type);
handle_builtin(compiler.get<SPIRType>(type->member_types[index]), decorations.builtin_type,
decorations.decoration_flags);
}
}
type = &compiler.get<SPIRType>(type->member_types[index]);
}
else
{
// No point in traversing further. We won't find any extra builtins.
break;
}
}
break;
}
default:
break;
}
return true;
}
void Compiler::update_active_builtins()
{
active_input_builtins.reset();
active_output_builtins.reset();
cull_distance_count = 0;
clip_distance_count = 0;
ActiveBuiltinHandler handler(*this);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
ir.for_each_typed_id<SPIRVariable>([&](uint32_t, const SPIRVariable &var) {
if (var.storage != StorageClassOutput)
return;
if (!interface_variable_exists_in_entry_point(var.self))
return;
// Also, make sure we preserve output variables which are only initialized, but never accessed by any code.
if (var.initializer != ID(0))
handler.add_if_builtin_or_block(var.self);
});
}
// Returns whether this shader uses a builtin of the storage class
bool Compiler::has_active_builtin(BuiltIn builtin, StorageClass storage) const
{
const Bitset *flags;
switch (storage)
{
case StorageClassInput:
flags = &active_input_builtins;
break;
case StorageClassOutput:
flags = &active_output_builtins;
break;
default:
return false;
}
return flags->get(builtin);
}
void Compiler::analyze_image_and_sampler_usage()
{
CombinedImageSamplerDrefHandler dref_handler(*this);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), dref_handler);
CombinedImageSamplerUsageHandler handler(*this, dref_handler.dref_combined_samplers);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
// Need to run this traversal twice. First time, we propagate any comparison sampler usage from leaf functions
// down to main().
// In the second pass, we can propagate up forced depth state coming from main() up into leaf functions.
handler.dependency_hierarchy.clear();
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
comparison_ids = std::move(handler.comparison_ids);
need_subpass_input = handler.need_subpass_input;
need_subpass_input_ms = handler.need_subpass_input_ms;
// Forward information from separate images and samplers into combined image samplers.
for (auto &combined : combined_image_samplers)
if (comparison_ids.count(combined.sampler_id))
comparison_ids.insert(combined.combined_id);
}
bool Compiler::CombinedImageSamplerDrefHandler::handle(spv::Op opcode, const uint32_t *args, uint32_t)
{
// Mark all sampled images which are used with Dref.
switch (opcode)
{
case OpImageSampleDrefExplicitLod:
case OpImageSampleDrefImplicitLod:
case OpImageSampleProjDrefExplicitLod:
case OpImageSampleProjDrefImplicitLod:
case OpImageSparseSampleProjDrefImplicitLod:
case OpImageSparseSampleDrefImplicitLod:
case OpImageSparseSampleProjDrefExplicitLod:
case OpImageSparseSampleDrefExplicitLod:
case OpImageDrefGather:
case OpImageSparseDrefGather:
dref_combined_samplers.insert(args[2]);
return true;
default:
break;
}
return true;
}
const CFG &Compiler::get_cfg_for_current_function() const
{
assert(current_function);
return get_cfg_for_function(current_function->self);
}
const CFG &Compiler::get_cfg_for_function(uint32_t id) const
{
auto cfg_itr = function_cfgs.find(id);
assert(cfg_itr != end(function_cfgs));
assert(cfg_itr->second);
return *cfg_itr->second;
}
void Compiler::build_function_control_flow_graphs_and_analyze()
{
CFGBuilder handler(*this);
handler.function_cfgs[ir.default_entry_point].reset(new CFG(*this, get<SPIRFunction>(ir.default_entry_point)));
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
function_cfgs = std::move(handler.function_cfgs);
bool single_function = function_cfgs.size() <= 1;
for (auto &f : function_cfgs)
{
auto &func = get<SPIRFunction>(f.first);
AnalyzeVariableScopeAccessHandler scope_handler(*this, func);
analyze_variable_scope(func, scope_handler);
find_function_local_luts(func, scope_handler, single_function);
// Check if we can actually use the loop variables we found in analyze_variable_scope.
// To use multiple initializers, we need the same type and qualifiers.
for (auto block : func.blocks)
{
auto &b = get<SPIRBlock>(block);
if (b.loop_variables.size() < 2)
continue;
auto &flags = get_decoration_bitset(b.loop_variables.front());
uint32_t type = get<SPIRVariable>(b.loop_variables.front()).basetype;
bool invalid_initializers = false;
for (auto loop_variable : b.loop_variables)
{
if (flags != get_decoration_bitset(loop_variable) ||
type != get<SPIRVariable>(b.loop_variables.front()).basetype)
{
invalid_initializers = true;
break;
}
}
if (invalid_initializers)
{
for (auto loop_variable : b.loop_variables)
get<SPIRVariable>(loop_variable).loop_variable = false;
b.loop_variables.clear();
}
}
}
// Find LUTs which are not function local. Only consider this case if the CFG is multi-function,
// otherwise we treat Private as Function trivially.
// Needs to be analyzed from the outside since we have to block the LUT optimization if at least
// one function writes to it.
if (!single_function)
{
for (auto &id : global_variables)
{
auto &var = get<SPIRVariable>(id);
auto &type = get_variable_data_type(var);
if (is_array(type) && var.storage == StorageClassPrivate &&
var.initializer && !var.is_written_to &&
ir.ids[var.initializer].get_type() == TypeConstant)
{
get<SPIRConstant>(var.initializer).is_used_as_lut = true;
var.static_expression = var.initializer;
var.statically_assigned = true;
var.remapped_variable = true;
}
}
}
}
Compiler::CFGBuilder::CFGBuilder(Compiler &compiler_)
: compiler(compiler_)
{
}
bool Compiler::CFGBuilder::handle(spv::Op, const uint32_t *, uint32_t)
{
return true;
}
bool Compiler::CFGBuilder::follow_function_call(const SPIRFunction &func)
{
if (function_cfgs.find(func.self) == end(function_cfgs))
{
function_cfgs[func.self].reset(new CFG(compiler, func));
return true;
}
else
return false;
}
void Compiler::CombinedImageSamplerUsageHandler::add_dependency(uint32_t dst, uint32_t src)
{
dependency_hierarchy[dst].insert(src);
// Propagate up any comparison state if we're loading from one such variable.
if (comparison_ids.count(src))
comparison_ids.insert(dst);
}
bool Compiler::CombinedImageSamplerUsageHandler::begin_function_scope(const uint32_t *args, uint32_t length)
{
if (length < 3)
return false;
auto &func = compiler.get<SPIRFunction>(args[2]);
const auto *arg = &args[3];
length -= 3;
for (uint32_t i = 0; i < length; i++)
{
auto &argument = func.arguments[i];
add_dependency(argument.id, arg[i]);
}
return true;
}
void Compiler::CombinedImageSamplerUsageHandler::add_hierarchy_to_comparison_ids(uint32_t id)
{
// Traverse the variable dependency hierarchy and tag everything in its path with comparison ids.
comparison_ids.insert(id);
for (auto &dep_id : dependency_hierarchy[id])
add_hierarchy_to_comparison_ids(dep_id);
}
bool Compiler::CombinedImageSamplerUsageHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
switch (opcode)
{
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
case OpLoad:
{
if (length < 3)
return false;
add_dependency(args[1], args[2]);
// Ideally defer this to OpImageRead, but then we'd need to track loaded IDs.
// If we load an image, we're going to use it and there is little harm in declaring an unused gl_FragCoord.
auto &type = compiler.get<SPIRType>(args[0]);
if (type.image.dim == DimSubpassData)
{
need_subpass_input = true;
if (type.image.ms)
need_subpass_input_ms = true;
}
// If we load a SampledImage and it will be used with Dref, propagate the state up.
if (dref_combined_samplers.count(args[1]) != 0)
add_hierarchy_to_comparison_ids(args[1]);
break;
}
case OpSampledImage:
{
if (length < 4)
return false;
// If the underlying resource has been used for comparison then duplicate loads of that resource must be too.
// This image must be a depth image.
uint32_t result_id = args[1];
uint32_t image = args[2];
uint32_t sampler = args[3];
if (dref_combined_samplers.count(result_id) != 0)
{
add_hierarchy_to_comparison_ids(image);
// This sampler must be a SamplerComparisonState, and not a regular SamplerState.
add_hierarchy_to_comparison_ids(sampler);
// Mark the OpSampledImage itself as being comparison state.
comparison_ids.insert(result_id);
}
return true;
}
default:
break;
}
return true;
}
bool Compiler::buffer_is_hlsl_counter_buffer(VariableID id) const
{
auto *m = ir.find_meta(id);
return m && m->hlsl_is_magic_counter_buffer;
}
bool Compiler::buffer_get_hlsl_counter_buffer(VariableID id, uint32_t &counter_id) const
{
auto *m = ir.find_meta(id);
// First, check for the proper decoration.
if (m && m->hlsl_magic_counter_buffer != 0)
{
counter_id = m->hlsl_magic_counter_buffer;
return true;
}
else
return false;
}
void Compiler::make_constant_null(uint32_t id, uint32_t type)
{
auto &constant_type = get<SPIRType>(type);
if (constant_type.pointer)
{
auto &constant = set<SPIRConstant>(id, type);
constant.make_null(constant_type);
}
else if (!constant_type.array.empty())
{
assert(constant_type.parent_type);
uint32_t parent_id = ir.increase_bound_by(1);
make_constant_null(parent_id, constant_type.parent_type);
if (!constant_type.array_size_literal.back())
SPIRV_CROSS_THROW("Array size of OpConstantNull must be a literal.");
SmallVector<uint32_t> elements(constant_type.array.back());
for (uint32_t i = 0; i < constant_type.array.back(); i++)
elements[i] = parent_id;
set<SPIRConstant>(id, type, elements.data(), uint32_t(elements.size()), false);
}
else if (!constant_type.member_types.empty())
{
uint32_t member_ids = ir.increase_bound_by(uint32_t(constant_type.member_types.size()));
SmallVector<uint32_t> elements(constant_type.member_types.size());
for (uint32_t i = 0; i < constant_type.member_types.size(); i++)
{
make_constant_null(member_ids + i, constant_type.member_types[i]);
elements[i] = member_ids + i;
}
set<SPIRConstant>(id, type, elements.data(), uint32_t(elements.size()), false);
}
else
{
auto &constant = set<SPIRConstant>(id, type);
constant.make_null(constant_type);
}
}
const SmallVector<spv::Capability> &Compiler::get_declared_capabilities() const
{
return ir.declared_capabilities;
}
const SmallVector<std::string> &Compiler::get_declared_extensions() const
{
return ir.declared_extensions;
}
std::string Compiler::get_remapped_declared_block_name(VariableID id) const
{
return get_remapped_declared_block_name(id, false);
}
std::string Compiler::get_remapped_declared_block_name(uint32_t id, bool fallback_prefer_instance_name) const
{
auto itr = declared_block_names.find(id);
if (itr != end(declared_block_names))
{
return itr->second;
}
else
{
auto &var = get<SPIRVariable>(id);
if (fallback_prefer_instance_name)
{
return to_name(var.self);
}
else
{
auto &type = get<SPIRType>(var.basetype);
auto *type_meta = ir.find_meta(type.self);
auto *block_name = type_meta ? &type_meta->decoration.alias : nullptr;
return (!block_name || block_name->empty()) ? get_block_fallback_name(id) : *block_name;
}
}
}
bool Compiler::reflection_ssbo_instance_name_is_significant() const
{
if (ir.source.known)
{
// UAVs from HLSL source tend to be declared in a way where the type is reused
// but the instance name is significant, and that's the name we should report.
// For GLSL, SSBOs each have their own block type as that's how GLSL is written.
return ir.source.hlsl;
}
unordered_set<uint32_t> ssbo_type_ids;
bool aliased_ssbo_types = false;
// If we don't have any OpSource information, we need to perform some shaky heuristics.
ir.for_each_typed_id<SPIRVariable>([&](uint32_t, const SPIRVariable &var) {
auto &type = this->get<SPIRType>(var.basetype);
if (!type.pointer || var.storage == StorageClassFunction)
return;
bool ssbo = var.storage == StorageClassStorageBuffer ||
(var.storage == StorageClassUniform && has_decoration(type.self, DecorationBufferBlock));
if (ssbo)
{
if (ssbo_type_ids.count(type.self))
aliased_ssbo_types = true;
else
ssbo_type_ids.insert(type.self);
}
});
// If the block name is aliased, assume we have HLSL-style UAV declarations.
return aliased_ssbo_types;
}
bool Compiler::instruction_to_result_type(uint32_t &result_type, uint32_t &result_id, spv::Op op,
const uint32_t *args, uint32_t length)
{
if (length < 2)
return false;
bool has_result_id = false, has_result_type = false;
HasResultAndType(op, &has_result_id, &has_result_type);
if (has_result_id && has_result_type)
{
result_type = args[0];
result_id = args[1];
return true;
}
else
return false;
}
Bitset Compiler::combined_decoration_for_member(const SPIRType &type, uint32_t index) const
{
Bitset flags;
auto *type_meta = ir.find_meta(type.self);
if (type_meta)
{
auto &members = type_meta->members;
if (index >= members.size())
return flags;
auto &dec = members[index];
flags.merge_or(dec.decoration_flags);
auto &member_type = get<SPIRType>(type.member_types[index]);
// If our member type is a struct, traverse all the child members as well recursively.
auto &member_childs = member_type.member_types;
for (uint32_t i = 0; i < member_childs.size(); i++)
{
auto &child_member_type = get<SPIRType>(member_childs[i]);
if (!child_member_type.pointer)
flags.merge_or(combined_decoration_for_member(member_type, i));
}
}
return flags;
}
bool Compiler::is_desktop_only_format(spv::ImageFormat format)
{
switch (format)
{
// Desktop-only formats
case ImageFormatR11fG11fB10f:
case ImageFormatR16f:
case ImageFormatRgb10A2:
case ImageFormatR8:
case ImageFormatRg8:
case ImageFormatR16:
case ImageFormatRg16:
case ImageFormatRgba16:
case ImageFormatR16Snorm:
case ImageFormatRg16Snorm:
case ImageFormatRgba16Snorm:
case ImageFormatR8Snorm:
case ImageFormatRg8Snorm:
case ImageFormatR8ui:
case ImageFormatRg8ui:
case ImageFormatR16ui:
case ImageFormatRgb10a2ui:
case ImageFormatR8i:
case ImageFormatRg8i:
case ImageFormatR16i:
return true;
default:
break;
}
return false;
}
// An image is determined to be a depth image if it is marked as a depth image and is not also
// explicitly marked with a color format, or if there are any sample/gather compare operations on it.
bool Compiler::is_depth_image(const SPIRType &type, uint32_t id) const
{
return (type.image.depth && type.image.format == ImageFormatUnknown) || comparison_ids.count(id);
}
bool Compiler::type_is_opaque_value(const SPIRType &type) const
{
return !type.pointer && (type.basetype == SPIRType::SampledImage || type.basetype == SPIRType::Image ||
type.basetype == SPIRType::Sampler);
}
// Make these member functions so we can easily break on any force_recompile events.
void Compiler::force_recompile()
{
is_force_recompile = true;
}
void Compiler::force_recompile_guarantee_forward_progress()
{
force_recompile();
is_force_recompile_forward_progress = true;
}
bool Compiler::is_forcing_recompilation() const
{
return is_force_recompile;
}
void Compiler::clear_force_recompile()
{
is_force_recompile = false;
is_force_recompile_forward_progress = false;
}
Compiler::PhysicalStorageBufferPointerHandler::PhysicalStorageBufferPointerHandler(Compiler &compiler_)
: compiler(compiler_)
{
}
Compiler::PhysicalBlockMeta *Compiler::PhysicalStorageBufferPointerHandler::find_block_meta(uint32_t id) const
{
auto chain_itr = access_chain_to_physical_block.find(id);
if (chain_itr != access_chain_to_physical_block.end())
return chain_itr->second;
else
return nullptr;
}
void Compiler::PhysicalStorageBufferPointerHandler::mark_aligned_access(uint32_t id, const uint32_t *args, uint32_t length)
{
uint32_t mask = *args;
args++;
length--;
if (length && (mask & MemoryAccessVolatileMask) != 0)
{
args++;
length--;
}
if (length && (mask & MemoryAccessAlignedMask) != 0)
{
uint32_t alignment = *args;
auto *meta = find_block_meta(id);
// This makes the assumption that the application does not rely on insane edge cases like:
// Bind buffer with ADDR = 8, use block offset of 8 bytes, load/store with 16 byte alignment.
// If we emit the buffer with alignment = 16 here, the first element at offset = 0 should
// actually have alignment of 8 bytes, but this is too theoretical and awkward to support.
// We could potentially keep track of any offset in the access chain, but it's
// practically impossible for high level compilers to emit code like that,
// so deducing overall alignment requirement based on maximum observed Alignment value is probably fine.
if (meta && alignment > meta->alignment)
meta->alignment = alignment;
}
}
bool Compiler::PhysicalStorageBufferPointerHandler::type_is_bda_block_entry(uint32_t type_id) const
{
auto &type = compiler.get<SPIRType>(type_id);
return compiler.is_physical_pointer(type);
}
uint32_t Compiler::PhysicalStorageBufferPointerHandler::get_minimum_scalar_alignment(const SPIRType &type) const
{
if (type.storage == spv::StorageClassPhysicalStorageBufferEXT)
return 8;
else if (type.basetype == SPIRType::Struct)
{
uint32_t alignment = 0;
for (auto &member_type : type.member_types)
{
uint32_t member_align = get_minimum_scalar_alignment(compiler.get<SPIRType>(member_type));
if (member_align > alignment)
alignment = member_align;
}
return alignment;
}
else
return type.width / 8;
}
void Compiler::PhysicalStorageBufferPointerHandler::setup_meta_chain(uint32_t type_id, uint32_t var_id)
{
if (type_is_bda_block_entry(type_id))
{
auto &meta = physical_block_type_meta[type_id];
access_chain_to_physical_block[var_id] = &meta;
auto &type = compiler.get<SPIRType>(type_id);
if (!compiler.is_physical_pointer_to_buffer_block(type))
non_block_types.insert(type_id);
if (meta.alignment == 0)
meta.alignment = get_minimum_scalar_alignment(compiler.get_pointee_type(type));
}
}
bool Compiler::PhysicalStorageBufferPointerHandler::handle(Op op, const uint32_t *args, uint32_t length)
{
// When a BDA pointer comes to life, we need to keep a mapping of SSA ID -> type ID for the pointer type.
// For every load and store, we'll need to be able to look up the type ID being accessed and mark any alignment
// requirements.
switch (op)
{
case OpConvertUToPtr:
case OpBitcast:
case OpCompositeExtract:
// Extract can begin a new chain if we had a struct or array of pointers as input.
// We don't begin chains before we have a pure scalar pointer.
setup_meta_chain(args[0], args[1]);
break;
case OpAccessChain:
case OpInBoundsAccessChain:
case OpPtrAccessChain:
case OpCopyObject:
{
auto itr = access_chain_to_physical_block.find(args[2]);
if (itr != access_chain_to_physical_block.end())
access_chain_to_physical_block[args[1]] = itr->second;
break;
}
case OpLoad:
{
setup_meta_chain(args[0], args[1]);
if (length >= 4)
mark_aligned_access(args[2], args + 3, length - 3);
break;
}
case OpStore:
{
if (length >= 3)
mark_aligned_access(args[0], args + 2, length - 2);
break;
}
default:
break;
}
return true;
}
uint32_t Compiler::PhysicalStorageBufferPointerHandler::get_base_non_block_type_id(uint32_t type_id) const
{
auto *type = &compiler.get<SPIRType>(type_id);
while (compiler.is_physical_pointer(*type) && !type_is_bda_block_entry(type_id))
{
type_id = type->parent_type;
type = &compiler.get<SPIRType>(type_id);
}
assert(type_is_bda_block_entry(type_id));
return type_id;
}
void Compiler::PhysicalStorageBufferPointerHandler::analyze_non_block_types_from_block(const SPIRType &type)
{
for (auto &member : type.member_types)
{
auto &subtype = compiler.get<SPIRType>(member);
if (compiler.is_physical_pointer(subtype) && !compiler.is_physical_pointer_to_buffer_block(subtype))
non_block_types.insert(get_base_non_block_type_id(member));
else if (subtype.basetype == SPIRType::Struct && !compiler.is_pointer(subtype))
analyze_non_block_types_from_block(subtype);
}
}
void Compiler::analyze_non_block_pointer_types()
{
PhysicalStorageBufferPointerHandler handler(*this);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
// Analyze any block declaration we have to make. It might contain
// physical pointers to POD types which we never used, and thus never added to the list.
// We'll need to add those pointer types to the set of types we declare.
ir.for_each_typed_id<SPIRType>([&](uint32_t id, SPIRType &type) {
// Only analyze the raw block struct, not any pointer-to-struct, since that's just redundant.
if (type.self == id &&
(has_decoration(type.self, DecorationBlock) ||
has_decoration(type.self, DecorationBufferBlock)))
{
handler.analyze_non_block_types_from_block(type);
}
});
physical_storage_non_block_pointer_types.reserve(handler.non_block_types.size());
for (auto type : handler.non_block_types)
physical_storage_non_block_pointer_types.push_back(type);
sort(begin(physical_storage_non_block_pointer_types), end(physical_storage_non_block_pointer_types));
physical_storage_type_to_alignment = std::move(handler.physical_block_type_meta);
}
bool Compiler::InterlockedResourceAccessPrepassHandler::handle(Op op, const uint32_t *, uint32_t)
{
if (op == OpBeginInvocationInterlockEXT || op == OpEndInvocationInterlockEXT)
{
if (interlock_function_id != 0 && interlock_function_id != call_stack.back())
{
// Most complex case, we have no sensible way of dealing with this
// other than taking the 100% conservative approach, exit early.
split_function_case = true;
return false;
}
else
{
interlock_function_id = call_stack.back();
// If this call is performed inside control flow we have a problem.
auto &cfg = compiler.get_cfg_for_function(interlock_function_id);
uint32_t from_block_id = compiler.get<SPIRFunction>(interlock_function_id).entry_block;
bool outside_control_flow = cfg.node_terminates_control_flow_in_sub_graph(from_block_id, current_block_id);
if (!outside_control_flow)
control_flow_interlock = true;
}
}
return true;
}
void Compiler::InterlockedResourceAccessPrepassHandler::rearm_current_block(const SPIRBlock &block)
{
current_block_id = block.self;
}
bool Compiler::InterlockedResourceAccessPrepassHandler::begin_function_scope(const uint32_t *args, uint32_t length)
{
if (length < 3)
return false;
call_stack.push_back(args[2]);
return true;
}
bool Compiler::InterlockedResourceAccessPrepassHandler::end_function_scope(const uint32_t *, uint32_t)
{
call_stack.pop_back();
return true;
}
bool Compiler::InterlockedResourceAccessHandler::begin_function_scope(const uint32_t *args, uint32_t length)
{
if (length < 3)
return false;
if (args[2] == interlock_function_id)
call_stack_is_interlocked = true;
call_stack.push_back(args[2]);
return true;
}
bool Compiler::InterlockedResourceAccessHandler::end_function_scope(const uint32_t *, uint32_t)
{
if (call_stack.back() == interlock_function_id)
call_stack_is_interlocked = false;
call_stack.pop_back();
return true;
}
void Compiler::InterlockedResourceAccessHandler::access_potential_resource(uint32_t id)
{
if ((use_critical_section && in_crit_sec) || (control_flow_interlock && call_stack_is_interlocked) ||
split_function_case)
{
compiler.interlocked_resources.insert(id);
}
}
bool Compiler::InterlockedResourceAccessHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
{
// Only care about critical section analysis if we have simple case.
if (use_critical_section)
{
if (opcode == OpBeginInvocationInterlockEXT)
{
in_crit_sec = true;
return true;
}
if (opcode == OpEndInvocationInterlockEXT)
{
// End critical section--nothing more to do.
return false;
}
}
// We need to figure out where images and buffers are loaded from, so do only the bare bones compilation we need.
switch (opcode)
{
case OpLoad:
{
if (length < 3)
return false;
uint32_t ptr = args[2];
auto *var = compiler.maybe_get_backing_variable(ptr);
// We're only concerned with buffer and image memory here.
if (!var)
break;
switch (var->storage)
{
default:
break;
case StorageClassUniformConstant:
{
uint32_t result_type = args[0];
uint32_t id = args[1];
compiler.set<SPIRExpression>(id, "", result_type, true);
compiler.register_read(id, ptr, true);
break;
}
case StorageClassUniform:
// Must have BufferBlock; we only care about SSBOs.
if (!compiler.has_decoration(compiler.get<SPIRType>(var->basetype).self, DecorationBufferBlock))
break;
// fallthrough
case StorageClassStorageBuffer:
access_potential_resource(var->self);
break;
}
break;
}
case OpInBoundsAccessChain:
case OpAccessChain:
case OpPtrAccessChain:
{
if (length < 3)
return false;
uint32_t result_type = args[0];
auto &type = compiler.get<SPIRType>(result_type);
if (type.storage == StorageClassUniform || type.storage == StorageClassUniformConstant ||
type.storage == StorageClassStorageBuffer)
{
uint32_t id = args[1];
uint32_t ptr = args[2];
compiler.set<SPIRExpression>(id, "", result_type, true);
compiler.register_read(id, ptr, true);
compiler.ir.ids[id].set_allow_type_rewrite();
}
break;
}
case OpImageTexelPointer:
{
if (length < 3)
return false;
uint32_t result_type = args[0];
uint32_t id = args[1];
uint32_t ptr = args[2];
auto &e = compiler.set<SPIRExpression>(id, "", result_type, true);
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var)
e.loaded_from = var->self;
break;
}
case OpStore:
case OpImageWrite:
case OpAtomicStore:
{
if (length < 1)
return false;
uint32_t ptr = args[0];
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var && (var->storage == StorageClassUniform || var->storage == StorageClassUniformConstant ||
var->storage == StorageClassStorageBuffer))
{
access_potential_resource(var->self);
}
break;
}
case OpCopyMemory:
{
if (length < 2)
return false;
uint32_t dst = args[0];
uint32_t src = args[1];
auto *dst_var = compiler.maybe_get_backing_variable(dst);
auto *src_var = compiler.maybe_get_backing_variable(src);
if (dst_var && (dst_var->storage == StorageClassUniform || dst_var->storage == StorageClassStorageBuffer))
access_potential_resource(dst_var->self);
if (src_var)
{
if (src_var->storage != StorageClassUniform && src_var->storage != StorageClassStorageBuffer)
break;
if (src_var->storage == StorageClassUniform &&
!compiler.has_decoration(compiler.get<SPIRType>(src_var->basetype).self, DecorationBufferBlock))
{
break;
}
access_potential_resource(src_var->self);
}
break;
}
case OpImageRead:
case OpAtomicLoad:
{
if (length < 3)
return false;
uint32_t ptr = args[2];
auto *var = compiler.maybe_get_backing_variable(ptr);
// We're only concerned with buffer and image memory here.
if (!var)
break;
switch (var->storage)
{
default:
break;
case StorageClassUniform:
// Must have BufferBlock; we only care about SSBOs.
if (!compiler.has_decoration(compiler.get<SPIRType>(var->basetype).self, DecorationBufferBlock))
break;
// fallthrough
case StorageClassUniformConstant:
case StorageClassStorageBuffer:
access_potential_resource(var->self);
break;
}
break;
}
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:
{
if (length < 3)
return false;
uint32_t ptr = args[2];
auto *var = compiler.maybe_get_backing_variable(ptr);
if (var && (var->storage == StorageClassUniform || var->storage == StorageClassUniformConstant ||
var->storage == StorageClassStorageBuffer))
{
access_potential_resource(var->self);
}
break;
}
default:
break;
}
return true;
}
void Compiler::analyze_interlocked_resource_usage()
{
if (get_execution_model() == ExecutionModelFragment &&
(get_entry_point().flags.get(ExecutionModePixelInterlockOrderedEXT) ||
get_entry_point().flags.get(ExecutionModePixelInterlockUnorderedEXT) ||
get_entry_point().flags.get(ExecutionModeSampleInterlockOrderedEXT) ||
get_entry_point().flags.get(ExecutionModeSampleInterlockUnorderedEXT)))
{
InterlockedResourceAccessPrepassHandler prepass_handler(*this, ir.default_entry_point);
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), prepass_handler);
InterlockedResourceAccessHandler handler(*this, ir.default_entry_point);
handler.interlock_function_id = prepass_handler.interlock_function_id;
handler.split_function_case = prepass_handler.split_function_case;
handler.control_flow_interlock = prepass_handler.control_flow_interlock;
handler.use_critical_section = !handler.split_function_case && !handler.control_flow_interlock;
traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), handler);
// For GLSL. If we hit any of these cases, we have to fall back to conservative approach.
interlocked_is_complex =
!handler.use_critical_section || handler.interlock_function_id != ir.default_entry_point;
}
}
// Helper function
bool Compiler::check_internal_recursion(const SPIRType &type, std::unordered_set<uint32_t> &checked_ids)
{
if (type.basetype != SPIRType::Struct)
return false;
if (checked_ids.count(type.self))
return true;
// Recurse into struct members
bool is_recursive = false;
checked_ids.insert(type.self);
uint32_t mbr_cnt = uint32_t(type.member_types.size());
for (uint32_t mbr_idx = 0; !is_recursive && mbr_idx < mbr_cnt; mbr_idx++)
{
uint32_t mbr_type_id = type.member_types[mbr_idx];
auto &mbr_type = get<SPIRType>(mbr_type_id);
is_recursive |= check_internal_recursion(mbr_type, checked_ids);
}
checked_ids.erase(type.self);
return is_recursive;
}
// Return whether the struct type contains a structural recursion nested somewhere within its content.
bool Compiler::type_contains_recursion(const SPIRType &type)
{
std::unordered_set<uint32_t> checked_ids;
return check_internal_recursion(type, checked_ids);
}
bool Compiler::type_is_array_of_pointers(const SPIRType &type) const
{
if (!is_array(type))
return false;
// BDA types must have parent type hierarchy.
if (!type.parent_type)
return false;
// Punch through all array layers.
auto *parent = &get<SPIRType>(type.parent_type);
while (is_array(*parent))
parent = &get<SPIRType>(parent->parent_type);
return is_pointer(*parent);
}
bool Compiler::flush_phi_required(BlockID from, BlockID to) const
{
auto &child = get<SPIRBlock>(to);
for (auto &phi : child.phi_variables)
if (phi.parent == from)
return true;
return false;
}
void Compiler::add_loop_level()
{
current_loop_level++;
}
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