| // Copyright 2022 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/tint/transform/var_for_dynamic_index.h" |
| |
| #include <utility> |
| |
| #include "src/tint/program_builder.h" |
| #include "src/tint/transform/utils/hoist_to_decl_before.h" |
| |
| namespace tint::transform { |
| |
| VarForDynamicIndex::VarForDynamicIndex() = default; |
| |
| VarForDynamicIndex::~VarForDynamicIndex() = default; |
| |
| Transform::ApplyResult VarForDynamicIndex::Apply(const Program* src, |
| const DataMap&, |
| DataMap&) const { |
| ProgramBuilder b; |
| CloneContext ctx{&b, src, /* auto_clone_symbols */ true}; |
| |
| HoistToDeclBefore hoist_to_decl_before(ctx); |
| |
| // Extracts array and matrix values that are dynamically indexed to a |
| // temporary `var` local that is then indexed. |
| auto dynamic_index_to_var = [&](const ast::IndexAccessorExpression* access_expr) { |
| auto* index_expr = access_expr->index; |
| auto* object_expr = access_expr->object; |
| auto& sem = src->Sem(); |
| |
| if (sem.GetVal(index_expr)->ConstantValue()) { |
| // Index expression resolves to a compile time value. |
| // As this isn't a dynamic index, we can ignore this. |
| return true; |
| } |
| |
| auto* indexed = sem.GetVal(object_expr); |
| if (!indexed->Type()->IsAnyOf<type::Array, type::Matrix>()) { |
| // We only care about array and matrices. |
| return true; |
| } |
| |
| // TODO(bclayton): group multiple accesses in the same object. |
| // e.g. arr[i] + arr[i+1] // Don't create two vars for this |
| return hoist_to_decl_before.Add(indexed, object_expr, HoistToDeclBefore::VariableKind::kVar, |
| "var_for_index"); |
| }; |
| |
| bool index_accessor_found = false; |
| for (auto* node : src->ASTNodes().Objects()) { |
| if (auto* access_expr = node->As<ast::IndexAccessorExpression>()) { |
| if (!dynamic_index_to_var(access_expr)) { |
| return Program(std::move(b)); |
| } |
| index_accessor_found = true; |
| } |
| } |
| if (!index_accessor_found) { |
| return SkipTransform; |
| } |
| |
| ctx.Clone(); |
| return Program(std::move(b)); |
| } |
| |
| } // namespace tint::transform |