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/*
* Copyright 2016 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.
*/
//
// Removes obviously unneeded code
//
#include <wasm.h>
#include <pass.h>
namespace wasm {
struct Vacuum : public WalkerPass<WasmWalker<Vacuum>> {
void visitBlock(Block *curr) {
// compress out nops
int skip = 0;
auto& list = curr->list;
size_t size = list.size();
for (size_t z = 0; z < size; z++) {
if (list[z]->is<Nop>()) {
skip++;
} else if (skip > 0) {
list[z - skip] = list[z];
}
}
if (skip > 0) {
list.resize(size - skip);
}
}
};
static RegisterPass<Vacuum> registerPass("vacuum", "removes obviously unneeded code");
} // namespace wasm
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