| // 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/remove_phonies.h" |
| |
| #include <memory> |
| #include <unordered_map> |
| #include <utility> |
| #include <vector> |
| |
| #include "src/ast/traverse_expressions.h" |
| #include "src/program_builder.h" |
| #include "src/sem/block_statement.h" |
| #include "src/sem/function.h" |
| #include "src/sem/statement.h" |
| #include "src/sem/variable.h" |
| #include "src/utils/map.h" |
| #include "src/utils/scoped_assignment.h" |
| |
| TINT_INSTANTIATE_TYPEINFO(tint::transform::RemovePhonies); |
| |
| namespace tint { |
| namespace transform { |
| namespace { |
| |
| struct SinkSignature { |
| std::vector<const sem::Type*> types; |
| |
| bool operator==(const SinkSignature& other) const { |
| if (types.size() != other.types.size()) { |
| return false; |
| } |
| for (size_t i = 0; i < types.size(); i++) { |
| if (types[i] != other.types[i]) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| struct Hasher { |
| /// @param sig the CallTargetSignature to hash |
| /// @return the hash value |
| std::size_t operator()(const SinkSignature& sig) const { |
| size_t hash = tint::utils::Hash(sig.types.size()); |
| for (auto* ty : sig.types) { |
| tint::utils::HashCombine(&hash, ty); |
| } |
| return hash; |
| } |
| }; |
| }; |
| |
| } // namespace |
| |
| RemovePhonies::RemovePhonies() = default; |
| |
| RemovePhonies::~RemovePhonies() = default; |
| |
| bool RemovePhonies::ShouldRun(const Program* program, const DataMap&) const { |
| for (auto* node : program->ASTNodes().Objects()) { |
| if (node->Is<ast::PhonyExpression>()) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| void RemovePhonies::Run(CloneContext& ctx, const DataMap&, DataMap&) const { |
| auto& sem = ctx.src->Sem(); |
| |
| std::unordered_map<SinkSignature, Symbol, SinkSignature::Hasher> sinks; |
| |
| for (auto* node : ctx.src->ASTNodes().Objects()) { |
| if (auto* stmt = node->As<ast::AssignmentStatement>()) { |
| if (stmt->lhs->Is<ast::PhonyExpression>()) { |
| std::vector<const ast::Expression*> side_effects; |
| if (!ast::TraverseExpressions( |
| stmt->rhs, ctx.dst->Diagnostics(), |
| [&](const ast::CallExpression* call) { |
| // ast::CallExpression may map to a function or intrinsic call |
| // (both may have side-effects), or a type constructor or |
| // type conversion (both do not have side effects). |
| if (sem.Get(call) |
| ->Target() |
| ->IsAnyOf<sem::Function, sem::Intrinsic>()) { |
| side_effects.push_back(call); |
| return ast::TraverseAction::Skip; |
| } |
| return ast::TraverseAction::Descend; |
| })) { |
| return; |
| } |
| |
| if (side_effects.empty()) { |
| // Phony assignment with no side effects. |
| // Just remove it. |
| RemoveStatement(ctx, stmt); |
| continue; |
| } |
| |
| if (side_effects.size() == 1) { |
| if (auto* call = side_effects[0]->As<ast::CallExpression>()) { |
| // Phony assignment with single call side effect. |
| // Replace phony assignment with call. |
| ctx.Replace( |
| stmt, [&, call] { return ctx.dst->CallStmt(ctx.Clone(call)); }); |
| continue; |
| } |
| } |
| |
| // Phony assignment with multiple side effects. |
| // Generate a call to a dummy function with the side effects as |
| // arguments. |
| ctx.Replace(stmt, [&, side_effects] { |
| SinkSignature sig; |
| for (auto* arg : side_effects) { |
| sig.types.push_back(sem.Get(arg)->Type()->UnwrapRef()); |
| } |
| auto sink = utils::GetOrCreate(sinks, sig, [&] { |
| auto name = ctx.dst->Symbols().New("phony_sink"); |
| ast::VariableList params; |
| for (auto* ty : sig.types) { |
| auto* ast_ty = CreateASTTypeFor(ctx, ty); |
| params.push_back( |
| ctx.dst->Param("p" + std::to_string(params.size()), ast_ty)); |
| } |
| ctx.dst->Func(name, params, ctx.dst->ty.void_(), {}); |
| return name; |
| }); |
| ast::ExpressionList args; |
| for (auto* arg : side_effects) { |
| args.push_back(ctx.Clone(arg)); |
| } |
| return ctx.dst->CallStmt(ctx.dst->Call(sink, args)); |
| }); |
| } |
| } |
| } |
| |
| ctx.Clone(); |
| } |
| |
| } // namespace transform |
| } // namespace tint |