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/*
* Copyright 2015 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.
*/
//
// Lowers if (x) y else z into
//
// L: {
// if (x) break (y) L
// z
// }
//
// This is useful for investigating how beneficial if_else is.
//
#include <memory>
#include <wasm.h>
#include <pass.h>
namespace wasm {
struct LowerIfElse : public WalkerPass<WasmWalker<LowerIfElse, void>> {
MixedArena* allocator;
std::unique_ptr<NameManager> namer;
void prepare(PassRunner* runner, Module *module) override {
allocator = runner->allocator;
namer = std::unique_ptr<NameManager>(new NameManager());
namer->run(runner, module);
}
void visitIf(If *curr) {
if (curr->ifFalse) {
auto block = allocator->alloc<Block>();
auto name = namer->getUnique("L"); // TODO: getUniqueInFunction
block->name = name;
block->list.push_back(curr);
block->list.push_back(curr->ifFalse);
block->finalize();
curr->ifFalse = nullptr;
auto break_ = allocator->alloc<Break>();
break_->name = name;
break_->value = curr->ifTrue;
curr->ifTrue = break_;
replaceCurrent(block);
}
}
};
static RegisterPass<LowerIfElse> registerPass("lower-if-else", "lowers if-elses into ifs, blocks and branches");
} // namespace wasm
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