Merge pull request #117 from HansKristian-Work/robust-atomic-bda

Implement robust BDA UAV counter updates.

dxil_converter.cpp

@@ -456,16 +456,10 @@ spv::Id Converter::Impl::create_bindless_heap_variable(const BindlessInfo &info)
 		{
 			if (info.counters)
 			{
-				if (!physical_counter_type)
-				{
-					spv::Id counter_type_id = get_struct_type({ builder().makeUintType(32) }, "AtomicCounter");
-					builder().addDecoration(counter_type_id, spv::DecorationBlock);
-					builder().addMemberDecoration(counter_type_id, 0, spv::DecorationOffset, 0);
-					physical_counter_type =
-					    builder().makePointer(spv::StorageClassPhysicalStorageBuffer, counter_type_id);
-				}
+				spv::Id uint_type = builder().makeUintType(32);
+				spv::Id uvec2_type = builder().makeVectorType(uint_type, 2);
 
-				spv::Id runtime_array_type_id = builder().makeRuntimeArray(physical_counter_type);
+				spv::Id runtime_array_type_id = builder().makeRuntimeArray(uvec2_type);
 				builder().addDecoration(runtime_array_type_id, spv::DecorationArrayStride, sizeof(uint64_t));
 
 				type_id = get_struct_type({ runtime_array_type_id }, "AtomicCounters");

opcodes/converter_impl.hpp

@@ -445,7 +445,6 @@ struct Converter::Impl
 	spv::Id cmpxchg_type = 0;
 	spv::Id texture_sample_pos_lut_id = 0;
 	spv::Id rasterizer_sample_count_id = 0;
-	spv::Id physical_counter_type = 0;
 	spv::Id shader_record_buffer_id = 0;
 	Vector<spv::Id> shader_record_buffer_types;
 

opcodes/dxil/dxil_buffer.cpp

@@ -27,6 +27,7 @@
 #include "dxil_sampling.hpp"
 #include "logging.hpp"
 #include "opcodes/converter_impl.hpp"
+#include "spirv_module.hpp"
 
 namespace dxil_spv
 {
@@ -1355,46 +1356,46 @@ bool emit_buffer_update_counter_instruction(Converter::Impl &impl, const llvm::C
 	const auto &meta = impl.handle_to_resource_meta[image_id];
 	int direction = llvm::cast<llvm::ConstantInt>(instruction->getOperand(2))->getUniqueInteger().getSExtValue();
 
-	Operation *counter_ptr_op;
-
 	if (meta.counter_is_physical_pointer)
 	{
-		counter_ptr_op = impl.allocate(
-		    spv::OpAccessChain, builder.makePointer(spv::StorageClassPhysicalStorageBuffer, builder.makeUintType(32)));
-		counter_ptr_op->add_id(meta.counter_var_id);
-		counter_ptr_op->add_id(builder.makeUintConstant(0));
+		spv::Id func_id = impl.spirv_module.get_helper_call_id(HelperCall::RobustAtomicCounter);
+		auto *op = impl.allocate(spv::OpFunctionCall, instruction);
+		op->add_id(func_id);
+		op->add_id(meta.counter_var_id);
+		op->add_id(builder.makeUintConstant(direction));
+		op->add_id(builder.makeUintConstant(direction < 0 ? -1u : 0u));
+		impl.add(op);
 	}
 	else
 	{
-		counter_ptr_op = impl.allocate(spv::OpImageTexelPointer,
-		                               builder.makePointer(spv::StorageClassImage, builder.makeUintType(32)));
+		auto *counter_ptr_op = impl.allocate(spv::OpImageTexelPointer,
+		                                     builder.makePointer(spv::StorageClassImage, builder.makeUintType(32)));
 
 		counter_ptr_op->add_id(meta.counter_var_id);
 		counter_ptr_op->add_id(builder.makeUintConstant(0));
 		counter_ptr_op->add_id(builder.makeUintConstant(0));
 
 		if (meta.non_uniform)
 			builder.addDecoration(counter_ptr_op->id, spv::DecorationNonUniformEXT);
-	}
+		impl.add(counter_ptr_op);
 
-	impl.add(counter_ptr_op);
-
-	Operation *op = impl.allocate(spv::OpAtomicIAdd, instruction);
-
-	op->add_id(counter_ptr_op->id);
-	op->add_id(builder.makeUintConstant(spv::ScopeDevice));
-	op->add_id(builder.makeUintConstant(0));
-	op->add_id(builder.makeUintConstant(direction));
+		auto *op = impl.allocate(spv::OpAtomicIAdd, instruction);
 
-	impl.add(op);
+		op->add_id(counter_ptr_op->id);
+		op->add_id(builder.makeUintConstant(spv::ScopeDevice));
+		op->add_id(builder.makeUintConstant(0));
+		op->add_id(builder.makeUintConstant(direction));
+		impl.add(op);
 
-	if (direction < 0)
-	{
 		spv::Id result_id = op->id;
-		op = impl.allocate(spv::OpISub, builder.makeUintType(32));
-		op->add_ids({ result_id, builder.makeUintConstant(1) });
-		impl.add(op);
-		impl.rewrite_value(instruction, op->id);
+
+		if (direction < 0)
+		{
+			op = impl.allocate(spv::OpISub, builder.makeUintType(32));
+			op->add_ids({ result_id, builder.makeUintConstant(1) });
+			impl.add(op);
+			impl.rewrite_value(instruction, op->id);
+		}
 	}
 
 	return true;

opcodes/dxil/dxil_resources.cpp

@@ -626,8 +626,11 @@ static spv::Id build_load_physical_pointer(Converter::Impl &impl, const Converte
 {
 	auto &builder = impl.builder();
 
+	spv::Id uint_type = builder.makeUintType(32);
+	spv::Id uvec2_type = builder.makeVectorType(uint_type, 2);
+
 	auto *chain_op = impl.allocate(spv::OpAccessChain,
-	                               builder.makePointer(spv::StorageClassStorageBuffer, impl.physical_counter_type));
+	                               builder.makePointer(spv::StorageClassStorageBuffer, uvec2_type));
 	chain_op->add_id(counter.var_id);
 	chain_op->add_id(builder.makeUintConstant(0));
 
@@ -638,7 +641,7 @@ static spv::Id build_load_physical_pointer(Converter::Impl &impl, const Converte
 	chain_op->add_id(offset_id);
 	impl.add(chain_op);
 
-	auto *load_op = impl.allocate(spv::OpLoad, impl.physical_counter_type);
+	auto *load_op = impl.allocate(spv::OpLoad, uvec2_type);
 	load_op->add_id(chain_op->id);
 	impl.add(load_op);