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archived-llvm/include/llvm/Transforms/Utils/UnifyFunctionExitNodes.h
Chandler Carruth 6b547686c5 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-19 08:50:56 +00:00

54 lines
1.9 KiB
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//===-- UnifyFunctionExitNodes.h - Ensure fn's have one return --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass is used to ensure that functions have at most one return and one
// unwind instruction in them. Additionally, it keeps track of which node is
// the new exit node of the CFG. If there are no return or unwind instructions
// in the function, the getReturnBlock/getUnwindBlock methods will return a null
// pointer.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H
#define LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H
#include "llvm/Pass.h"
#include "llvm/PassRegistry.h"
namespace llvm {
struct UnifyFunctionExitNodes : public FunctionPass {
BasicBlock *ReturnBlock = nullptr;
BasicBlock *UnwindBlock = nullptr;
BasicBlock *UnreachableBlock;
public:
static char ID; // Pass identification, replacement for typeid
UnifyFunctionExitNodes() : FunctionPass(ID) {
initializeUnifyFunctionExitNodesPass(*PassRegistry::getPassRegistry());
}
// We can preserve non-critical-edgeness when we unify function exit nodes
void getAnalysisUsage(AnalysisUsage &AU) const override;
// getReturn|Unwind|UnreachableBlock - Return the new single (or nonexistent)
// return, unwind, or unreachable basic blocks in the CFG.
//
BasicBlock *getReturnBlock() const { return ReturnBlock; }
BasicBlock *getUnwindBlock() const { return UnwindBlock; }
BasicBlock *getUnreachableBlock() const { return UnreachableBlock; }
bool runOnFunction(Function &F) override;
};
Pass *createUnifyFunctionExitNodesPass();
} // end namespace llvm
#endif // LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H