llvm-project/llvm/unittests/IR/CFGBuilder.h

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C++

//===- CFGBuilder.h - CFG building and updating utility ----------*- 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
//
//===----------------------------------------------------------------------===//
/// \file
/// CFGBuilders provides utilities fo building and updating CFG for testing
/// purposes.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_UNITTESTS_CFG_BUILDER_H
#define LLVM_UNITTESTS_CFG_BUILDER_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Debug.h"
#include <memory>
#include <set>
#include <tuple>
#include <vector>
namespace llvm {
class LLVMContext;
class Module;
class Function;
class BasicBlock;
class raw_ostream;
struct CFGHolder {
std::unique_ptr<LLVMContext> Context;
std::unique_ptr<Module> M;
Function *F;
CFGHolder(StringRef ModuleName = "m", StringRef FunctionName = "foo");
~CFGHolder(); // Defined in the .cpp file so we can use forward declarations.
};
/// \brief
/// CFGBuilder builds IR with specific CFG, based on the supplied list of arcs.
/// It's able to apply the provided updates and automatically modify the IR.
///
/// Internally it makes every basic block end with either SwitchInst or with
/// UnreachableInst. When all arc to a BB are deleted, the BB remains in the
/// function and doesn't get deleted.
///
class CFGBuilder {
public:
struct Arc {
StringRef From;
StringRef To;
friend bool operator<(const Arc &LHS, const Arc &RHS) {
return std::tie(LHS.From, LHS.To) <
std::tie(RHS.From, RHS.To);
}
};
enum class ActionKind { Insert, Delete };
struct Update {
ActionKind Action;
Arc Edge;
};
CFGBuilder(Function *F, const std::vector<Arc> &InitialArcs,
std::vector<Update> Updates);
BasicBlock *getOrAddBlock(StringRef BlockName);
Optional<Update> getNextUpdate() const;
Optional<Update> applyUpdate();
void dump(raw_ostream &OS = dbgs()) const;
private:
void buildCFG(const std::vector<Arc> &Arcs);
bool connect(const Arc &A);
bool disconnect(const Arc &A);
Function *F;
unsigned UpdateIdx = 0;
StringMap<BasicBlock *> NameToBlock;
std::set<Arc> Arcs;
std::vector<Update> Updates;
};
} // namespace llvm
#endif