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/*
* Copyright 2017 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_ast_branch_h
#define wasm_ast_branch_h
#include "wasm.h"
#include "wasm-traversal.h"
namespace wasm {
namespace BranchUtils {
// branches not actually taken (e.g. (br $out (unreachable)))
// are trivially ignored in our type system
inline bool isBranchTaken(Break* br) {
return !(br->value && br->value->type == unreachable) &&
!(br->condition && br->condition->type == unreachable);
}
inline bool isBranchTaken(Switch* sw) {
return !(sw->value && sw->value->type == unreachable) &&
sw->condition->type != unreachable;
}
// returns the set of targets to which we branch that are
// outside of a node
inline std::set<Name> getExitingBranches(Expression* ast) {
struct Scanner : public PostWalker<Scanner> {
std::set<Name> targets;
void visitBreak(Break* curr) {
targets.insert(curr->name);
}
void visitSwitch(Switch* curr) {
for (auto target : targets) {
targets.insert(target);
}
targets.insert(curr->default_);
}
void visitBlock(Block* curr) {
if (curr->name.is()) {
targets.erase(curr->name);
}
}
void visitLoop(Loop* curr) {
if (curr->name.is()) {
targets.erase(curr->name);
}
}
};
Scanner scanner;
scanner.walk(ast);
// anything not erased is a branch out
return scanner.targets;
}
// returns the list of all branch targets in a node
inline std::set<Name> getBranchTargets(Expression* ast) {
struct Scanner : public PostWalker<Scanner> {
std::set<Name> targets;
void visitBlock(Block* curr) {
if (curr->name.is()) {
targets.insert(curr->name);
}
}
void visitLoop(Loop* curr) {
if (curr->name.is()) {
targets.insert(curr->name);
}
}
};
Scanner scanner;
scanner.walk(ast);
return scanner.targets;
}
} // namespace BranchUtils
} // namespace wasm
#endif // wasm_ast_branch_h
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