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//===- llvm/Analysis/DominanceFrontier.h - Dominator Frontiers --*- 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 file defines the DominanceFrontier class, which calculate and holds the
// dominance frontier for a function.
//
// This should be considered deprecated, don't add any more uses of this data
// structure.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DOMINANCEFRONTIER_H
#define LLVM_ANALYSIS_DOMINANCEFRONTIER_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/GenericDomTree.h"
#include <cassert>
#include <utility>
namespace llvm {
class BasicBlock;
class Function;
class raw_ostream;
//===----------------------------------------------------------------------===//
/// DominanceFrontierBase - Common base class for computing forward and inverse
/// dominance frontiers for a function.
///
template <class BlockT, bool IsPostDom>
class DominanceFrontierBase {
public:
// Dom set for a bb. Use SetVector to make iterating dom frontiers of a bb
// deterministic.
using DomSetType = SetVector<BlockT *>;
using DomSetMapType = DenseMap<BlockT *, DomSetType>; // Dom set map
protected:
using BlockTraits = GraphTraits<BlockT *>;
DomSetMapType Frontiers;
// Postdominators can have multiple roots.
SmallVector<BlockT *, IsPostDom ? 4 : 1> Roots;
static constexpr bool IsPostDominators = IsPostDom;
public:
DominanceFrontierBase() = default;
/// getRoots - Return the root blocks of the current CFG. This may include
/// multiple blocks if we are computing post dominators. For forward
/// dominators, this will always be a single block (the entry node).
const SmallVectorImpl<BlockT *> &getRoots() const { return Roots; }
BlockT *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
return Roots[0];
}
/// isPostDominator - Returns true if analysis based of postdoms
bool isPostDominator() const {
return IsPostDominators;
}
void releaseMemory() {
Frontiers.clear();
}
// Accessor interface:
using iterator = typename DomSetMapType::iterator;
using const_iterator = typename DomSetMapType::const_iterator;
iterator begin() { return Frontiers.begin(); }
const_iterator begin() const { return Frontiers.begin(); }
iterator end() { return Frontiers.end(); }
const_iterator end() const { return Frontiers.end(); }
iterator find(BlockT *B) { return Frontiers.find(B); }
const_iterator find(BlockT *B) const { return Frontiers.find(B); }
iterator addBasicBlock(BlockT *BB, const DomSetType &frontier) {
assert(find(BB) == end() && "Block already in DominanceFrontier!");
return Frontiers.insert(std::make_pair(BB, frontier)).first;
}
/// removeBlock - Remove basic block BB's frontier.
void removeBlock(BlockT *BB);
void addToFrontier(iterator I, BlockT *Node);
void removeFromFrontier(iterator I, BlockT *Node);
/// compareDomSet - Return false if two domsets match. Otherwise
/// return true;
bool compareDomSet(DomSetType &DS1, const DomSetType &DS2) const;
/// compare - Return false if the other dominance frontier base matches
/// this dominance frontier base. Otherwise return true.
bool compare(DominanceFrontierBase &Other) const;
/// print - Convert to human readable form
///
void print(raw_ostream &OS) const;
/// dump - Dump the dominance frontier to dbgs().
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void dump() const;
#endif
};
//===-------------------------------------
/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
/// used to compute a forward dominator frontiers.
///
template <class BlockT>
class ForwardDominanceFrontierBase
: public DominanceFrontierBase<BlockT, false> {
private:
using BlockTraits = GraphTraits<BlockT *>;
public:
using DomTreeT = DomTreeBase<BlockT>;
using DomTreeNodeT = DomTreeNodeBase<BlockT>;
using DomSetType = typename DominanceFrontierBase<BlockT, false>::DomSetType;
void analyze(DomTreeT &DT) {
assert(DT.root_size() == 1 &&
"Only one entry block for forward domfronts!");
this->Roots = {DT.getRoot()};
calculate(DT, DT[this->Roots[0]]);
}
const DomSetType &calculate(const DomTreeT &DT, const DomTreeNodeT *Node);
};
class DominanceFrontier : public ForwardDominanceFrontierBase<BasicBlock> {
public:
using DomTreeT = DomTreeBase<BasicBlock>;
using DomTreeNodeT = DomTreeNodeBase<BasicBlock>;
using DomSetType = DominanceFrontierBase<BasicBlock, false>::DomSetType;
using iterator = DominanceFrontierBase<BasicBlock, false>::iterator;
using const_iterator =
DominanceFrontierBase<BasicBlock, false>::const_iterator;
/// Handle invalidation explicitly.
bool invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &);
};
class DominanceFrontierWrapperPass : public FunctionPass {
DominanceFrontier DF;
public:
static char ID; // Pass ID, replacement for typeid
DominanceFrontierWrapperPass();
DominanceFrontier &getDominanceFrontier() { return DF; }
const DominanceFrontier &getDominanceFrontier() const { return DF; }
void releaseMemory() override;
bool runOnFunction(Function &) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
void print(raw_ostream &OS, const Module * = nullptr) const override;
void dump() const;
};
extern template class DominanceFrontierBase<BasicBlock, false>;
extern template class DominanceFrontierBase<BasicBlock, true>;
extern template class ForwardDominanceFrontierBase<BasicBlock>;
/// Analysis pass which computes a \c DominanceFrontier.
class DominanceFrontierAnalysis
: public AnalysisInfoMixin<DominanceFrontierAnalysis> {
friend AnalysisInfoMixin<DominanceFrontierAnalysis>;
static AnalysisKey Key;
public:
/// Provide the result type for this analysis pass.
using Result = DominanceFrontier;
/// Run the analysis pass over a function and produce a dominator tree.
DominanceFrontier run(Function &F, FunctionAnalysisManager &AM);
};
/// Printer pass for the \c DominanceFrontier.
class DominanceFrontierPrinterPass
: public PassInfoMixin<DominanceFrontierPrinterPass> {
raw_ostream &OS;
public:
explicit DominanceFrontierPrinterPass(raw_ostream &OS);
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
static bool isRequired() { return true; }
};
} // end namespace llvm
#endif // LLVM_ANALYSIS_DOMINANCEFRONTIER_H
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