From bbfee5cc3a463b1bc7f54414ccaf2e47bee3e216 Mon Sep 17 00:00:00 2001 From: Alon Zakai Date: Mon, 1 Nov 2021 15:36:41 -0700 Subject: [Wasm GC] LUBFinder helper. NFC (#4298) This is a minor refactoring in DAE to have a helper class that does the incremental LUB calculation. The class is also used in LocalSubtyping, where it has the effect of making the work incremental which it was not before (that would have no observable consequence, but it should make us faster in the common case where we fail to find a new LUB). This will allow further optimization in a central place later. --- src/ir/lubs.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 src/ir/lubs.h (limited to 'src/ir/lubs.h') diff --git a/src/ir/lubs.h b/src/ir/lubs.h new file mode 100644 index 000000000..b75932091 --- /dev/null +++ b/src/ir/lubs.h @@ -0,0 +1,46 @@ +/* + * Copyright 2021 WebAssembly Community Group participants + * + * 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. + */ + +#ifndef wasm_ir_lubs_h +#define wasm_ir_lubs_h + +#include "ir/module-utils.h" +#include "wasm.h" + +namespace wasm { + +// Helper to find a LUB of a series of expressions. This works incrementally so +// that if we see we are not improving on an existing type then we can stop +// early. +struct LUBFinder { + // The least upper bound we found so far. + Type lub = Type::unreachable; + + // Note another type to take into account in the lub. Returns the new lub. + Type note(Type type) { return lub = Type::getLeastUpperBound(lub, type); } + + Type note(Expression* curr) { return note(curr->type); } + + // Returns whether we noted any (reachable) value. + bool noted() { return lub != Type::unreachable; } + + // Returns the lub that we found. + Type get() { return lub; } +}; + +} // namespace wasm + +#endif // wasm_ir_lubs_h -- cgit v1.2.3