| // Copyright 2021 The Tint Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "src/transform/num_workgroups_from_uniform.h" |
| |
| #include <memory> |
| #include <string> |
| #include <unordered_set> |
| #include <utility> |
| |
| #include "src/program_builder.h" |
| #include "src/sem/function.h" |
| #include "src/transform/canonicalize_entry_point_io.h" |
| #include "src/utils/hash.h" |
| |
| TINT_INSTANTIATE_TYPEINFO(tint::transform::NumWorkgroupsFromUniform); |
| TINT_INSTANTIATE_TYPEINFO(tint::transform::NumWorkgroupsFromUniform::Config); |
| |
| namespace tint { |
| namespace transform { |
| namespace { |
| /// Accessor describes the identifiers used in a member accessor that is being |
| /// used to retrieve the num_workgroups builtin from a parameter. |
| struct Accessor { |
| Symbol param; |
| Symbol member; |
| |
| /// Equality operator |
| bool operator==(const Accessor& other) const { |
| return param == other.param && member == other.member; |
| } |
| /// Hash function |
| struct Hasher { |
| size_t operator()(const Accessor& a) const { |
| return utils::Hash(a.param, a.member); |
| } |
| }; |
| }; |
| } // namespace |
| |
| NumWorkgroupsFromUniform::NumWorkgroupsFromUniform() = default; |
| NumWorkgroupsFromUniform::~NumWorkgroupsFromUniform() = default; |
| |
| bool NumWorkgroupsFromUniform::ShouldRun(const Program* program, |
| const DataMap&) const { |
| for (auto* node : program->ASTNodes().Objects()) { |
| if (auto* deco = node->As<ast::BuiltinDecoration>()) { |
| if (deco->builtin == ast::Builtin::kNumWorkgroups) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| void NumWorkgroupsFromUniform::Run(CloneContext& ctx, |
| const DataMap& inputs, |
| DataMap&) const { |
| auto* cfg = inputs.Get<Config>(); |
| if (cfg == nullptr) { |
| ctx.dst->Diagnostics().add_error( |
| diag::System::Transform, |
| "missing transform data for " + std::string(TypeInfo().name)); |
| return; |
| } |
| |
| const char* kNumWorkgroupsMemberName = "num_workgroups"; |
| |
| // Find all entry point parameters that declare the num_workgroups builtin. |
| std::unordered_set<Accessor, Accessor::Hasher> to_replace; |
| for (auto* func : ctx.src->AST().Functions()) { |
| // num_workgroups is only valid for compute stages. |
| if (func->PipelineStage() != ast::PipelineStage::kCompute) { |
| continue; |
| } |
| |
| for (auto* param : ctx.src->Sem().Get(func)->Parameters()) { |
| // Because the CanonicalizeEntryPointIO transform has been run, builtins |
| // will only appear as struct members. |
| auto* str = param->Type()->As<sem::Struct>(); |
| if (!str) { |
| continue; |
| } |
| |
| for (auto* member : str->Members()) { |
| auto* builtin = ast::GetDecoration<ast::BuiltinDecoration>( |
| member->Declaration()->decorations); |
| if (!builtin || builtin->builtin != ast::Builtin::kNumWorkgroups) { |
| continue; |
| } |
| |
| // Capture the symbols that would be used to access this member, which |
| // we will replace later. We currently have no way to get from the |
| // parameter directly to the member accessor expressions that use it. |
| to_replace.insert( |
| {param->Declaration()->symbol, member->Declaration()->symbol}); |
| |
| // Remove the struct member. |
| // The CanonicalizeEntryPointIO transform will have generated this |
| // struct uniquely for this particular entry point, so we know that |
| // there will be no other uses of this struct in the module and that we |
| // can safely modify it here. |
| ctx.Remove(str->Declaration()->members, member->Declaration()); |
| |
| // If this is the only member, remove the struct and parameter too. |
| if (str->Members().size() == 1) { |
| ctx.Remove(func->params, param->Declaration()); |
| ctx.Remove(ctx.src->AST().GlobalDeclarations(), str->Declaration()); |
| } |
| } |
| } |
| } |
| |
| // Get (or create, on first call) the uniform buffer that will receive the |
| // number of workgroups. |
| const ast::Variable* num_workgroups_ubo = nullptr; |
| auto get_ubo = [&]() { |
| if (!num_workgroups_ubo) { |
| auto* num_workgroups_struct = ctx.dst->Structure( |
| ctx.dst->Sym(), |
| {ctx.dst->Member(kNumWorkgroupsMemberName, |
| ctx.dst->ty.vec3(ctx.dst->ty.u32()))}); |
| num_workgroups_ubo = ctx.dst->Global( |
| ctx.dst->Sym(), ctx.dst->ty.Of(num_workgroups_struct), |
| ast::StorageClass::kUniform, |
| ast::DecorationList{ctx.dst->GroupAndBinding( |
| cfg->ubo_binding.group, cfg->ubo_binding.binding)}); |
| } |
| return num_workgroups_ubo; |
| }; |
| |
| // Now replace all the places where the builtins are accessed with the value |
| // loaded from the uniform buffer. |
| for (auto* node : ctx.src->ASTNodes().Objects()) { |
| auto* accessor = node->As<ast::MemberAccessorExpression>(); |
| if (!accessor) { |
| continue; |
| } |
| auto* ident = accessor->structure->As<ast::IdentifierExpression>(); |
| if (!ident) { |
| continue; |
| } |
| |
| if (to_replace.count({ident->symbol, accessor->member->symbol})) { |
| ctx.Replace(accessor, ctx.dst->MemberAccessor(get_ubo()->symbol, |
| kNumWorkgroupsMemberName)); |
| } |
| } |
| |
| ctx.Clone(); |
| } |
| |
| NumWorkgroupsFromUniform::Config::Config(sem::BindingPoint ubo_bp) |
| : ubo_binding(ubo_bp) {} |
| NumWorkgroupsFromUniform::Config::Config(const Config&) = default; |
| NumWorkgroupsFromUniform::Config::~Config() = default; |
| |
| } // namespace transform |
| } // namespace tint |