//===- RegionInfo.h - SESE region analysis ----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Calculate a program structure tree built out of single entry single exit
// regions.
// The basic ideas are taken from "The Program Structure Tree - Richard Johnson,
// David Pearson, Keshav Pingali - 1994", however enriched with ideas from "The
// Refined Process Structure Tree - Jussi Vanhatalo, Hagen Voelyer, Jana
// Koehler - 2009".
// The algorithm to calculate these data structures however is completely
// different, as it takes advantage of existing information already available
// in (Post)dominace tree and dominance frontier passes. This leads to a simpler
// and in practice hopefully better performing algorithm. The runtime of the
// algorithms described in the papers above are both linear in graph size,
// O(V+E), whereas this algorithm is not, as the dominance frontier information
// itself is not, but in practice runtime seems to be in the order of magnitude
// of dominance tree calculation.
//
// WARNING: LLVM is generally very concerned about compile time such that
// the use of additional analysis passes in the default
// optimization sequence is avoided as much as possible.
// Specifically, if you do not need the RegionInfo, but dominance
// information could be sufficient please base your work only on
// the dominator tree. Most passes maintain it, such that using
// it has often near zero cost. In contrast RegionInfo is by
// default not available, is not maintained by existing
// transformations and there is no intention to do so.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_REGIONINFO_H
#define LLVM_ANALYSIS_REGIONINFO_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <type_traits>
#include <vector>
namespace llvm {
class DominanceFrontier;
class DominatorTree;
class Loop;
class LoopInfo;
class PostDominatorTree;
class Region;
template <class RegionTr> class RegionBase;
class RegionInfo;
template <class RegionTr> class RegionInfoBase;
class RegionNode;
// Class to be specialized for different users of RegionInfo
// (i.e. BasicBlocks or MachineBasicBlocks). This is only to avoid needing to
// pass around an unreasonable number of template parameters.
template <class FuncT_>
struct RegionTraits {
// FuncT
// BlockT
// RegionT
// RegionNodeT
// RegionInfoT
using BrokenT = typename FuncT_::UnknownRegionTypeError;
};
template <>
struct RegionTraits<Function> {
using FuncT = Function;
using BlockT = BasicBlock;
using RegionT = Region;
using RegionNodeT = RegionNode;
using RegionInfoT = RegionInfo;
using DomTreeT = DominatorTree;
using DomTreeNodeT = DomTreeNode;
using DomFrontierT = DominanceFrontier;
using PostDomTreeT = PostDominatorTree;
using InstT = Instruction;
using LoopT = Loop;
using LoopInfoT = LoopInfo;
static unsigned getNumSuccessors(BasicBlock *BB) {
return BB->getTerminator()->getNumSuccessors();
}
};
/// Marker class to iterate over the elements of a Region in flat mode.
///
/// The class is used to either iterate in Flat mode or by not using it to not
/// iterate in Flat mode. During a Flat mode iteration all Regions are entered
/// and the iteration returns every BasicBlock. If the Flat mode is not
/// selected for SubRegions just one RegionNode containing the subregion is
/// returned.
template <class GraphType>
class FlatIt {};
/// A RegionNode represents a subregion or a BasicBlock that is part of a
/// Region.
template <class Tr>
class RegionNodeBase {
friend class RegionBase<Tr>;
public:
using BlockT = typename Tr::BlockT;
using RegionT = typename Tr::RegionT;
private:
/// This is the entry basic block that starts this region node. If this is a
/// BasicBlock RegionNode, then entry is just the basic block, that this
/// RegionNode represents. Otherwise it is the entry of this (Sub)RegionNode.
///
/// In the BBtoRegionNode map of the parent of this node, BB will always map
/// to this node no matter which kind of node this one is.
///
/// The node can hold either a Region or a BasicBlock.
/// Use one bit to save, if this RegionNode is a subregion or BasicBlock
/// RegionNode.
PointerIntPair<BlockT *, 1, bool> entry;
/// The parent Region of this RegionNode.
/// @see getParent()
RegionT *parent;
protected:
/// Create a RegionNode.
///
/// @param Parent The parent of this RegionNode.
/// @param Entry The entry BasicBlock of the RegionNode. If this
/// RegionNode represents a BasicBlock, this is the
/// BasicBlock itself. If it represents a subregion, this
/// is the entry BasicBlock of the subregion.
/// @param isSubRegion If this RegionNode represents a SubRegion.
inline RegionNodeBase(RegionT *Parent, BlockT *Entry,
bool isSubRegion = false)
: entry(Entry, isSubRegion), parent(Parent) {}
public:
RegionNodeBase(const RegionNodeBase &) = delete;
RegionNodeBase &operator=(const RegionNodeBase &) = delete;
/// Get the parent Region of this RegionNode.
///
/// The parent Region is the Region this RegionNode belongs to. If for
/// example a BasicBlock is element of two Regions, there exist two
/// RegionNodes for this BasicBlock. Each with the getParent() function
/// pointing to the Region this RegionNode belongs to.
///
/// @return Get the parent Region of this RegionNode.
inline RegionT *getParent() const { return parent; }
/// Get the entry BasicBlock of this RegionNode.
///
/// If this RegionNode represents a BasicBlock this is just the BasicBlock
/// itself, otherwise we return the entry BasicBlock of the Subregion
///
/// @return The entry BasicBlock of this RegionNode.
inline BlockT *getEntry() const { return entry.getPointer(); }
/// Get the content of this RegionNode.
///
/// This can be either a BasicBlock or a subregion. Before calling getNodeAs()
/// check the type of the content with the isSubRegion() function call.
///
/// @return The content of this RegionNode.
template <class T> inline T *getNodeAs() const;
/// Is this RegionNode a subregion?
///
/// @return True if it contains a subregion. False if it contains a
/// BasicBlock.
inline bool isSubRegion() const { return entry.getInt(); }
};
//===----------------------------------------------------------------------===//
/// A single entry single exit Region.
///
/// A Region is a connected subgraph of a control flow graph that has exactly
/// two connections to the remaining graph. It can be used to analyze or
/// optimize parts of the control flow graph.
///
/// A <em> simple Region </em> is connected to the remaining graph by just two
/// edges. One edge entering the Region and another one leaving the Region.
///
/// An <em> extended Region </em> (or just Region) is a subgraph that can be
/// transform into a simple Region. The transformation is done by adding
/// BasicBlocks that merge several entry or exit edges so that after the merge
/// just one entry and one exit edge exists.
///
/// The \e Entry of a Region is the first BasicBlock that is passed after
/// entering the Region. It is an element of the Region. The entry BasicBlock
/// dominates all BasicBlocks in the Region.
///
/// The \e Exit of a Region is the first BasicBlock that is passed after
/// leaving the Region. It is not an element of the Region. The exit BasicBlock,
/// postdominates all BasicBlocks in the Region.
///
/// A <em> canonical Region </em> cannot be constructed by combining smaller
/// Regions.
///
/// Region A is the \e parent of Region B, if B is completely contained in A.
///
/// Two canonical Regions either do not intersect at all or one is
/// the parent of the other.
///
/// The <em> Program Structure Tree</em> is a graph (V, E) where V is the set of
/// Regions in the control flow graph and E is the \e parent relation of these
/// Regions.
///
/// Example:
///
/// \verbatim
/// A simple control flow graph, that contains two regions.
///
/// 1
/// / |
/// 2 |
/// / \ 3
/// 4 5 |
/// | | |
/// 6 7 8
/// \ | /
/// \ |/ Region A: 1 -> 9 {1,2,3,4,5,6,7,8}
/// 9 Region B: 2 -> 9 {2,4,5,6,7}
/// \endverbatim
///
/// You can obtain more examples by either calling
///
/// <tt> "opt -regions -analyze anyprogram.ll" </tt>
/// or
/// <tt> "opt -view-regions-only anyprogram.ll" </tt>
///
/// on any LLVM file you are interested in.
///
/// The first call returns a textual representation of the program structure
/// tree, the second one creates a graphical representation using graphviz.
template <class Tr>
class RegionBase : public RegionNodeBase<Tr> {
friend class RegionInfoBase<Tr>;
using FuncT = typename Tr::FuncT;
using BlockT = typename Tr::BlockT;
using RegionInfoT = typename Tr::RegionInfoT;
using RegionT = typename Tr::RegionT;
using RegionNodeT = typename Tr::RegionNodeT;
using DomTreeT = typename Tr::DomTreeT;
using LoopT = typename Tr::LoopT;
using LoopInfoT = typename Tr::LoopInfoT;
using InstT = typename Tr::InstT;
using BlockTraits = GraphTraits<BlockT *>;
using InvBlockTraits = GraphTraits<Inverse<BlockT *>>;
using SuccIterTy = typename BlockTraits::ChildIteratorType;
using PredIterTy = typename InvBlockTraits::ChildIteratorType;
// Information necessary to manage this Region.
RegionInfoT *RI;
DomTreeT *DT;
// The exit BasicBlock of this region.
// (The entry BasicBlock is part of RegionNode)
BlockT *exit;
using RegionSet = std::vector<std::unique_ptr<RegionT>>;
// The subregions of this region.
RegionSet children;
using BBNodeMapT = std::map<BlockT *, std::unique_ptr<RegionNodeT>>;
// Save the BasicBlock RegionNodes that are element of this Region.
mutable BBNodeMapT BBNodeMap;
/// Check if a BB is in this Region. This check also works
/// if the region is incorrectly built. (EXPENSIVE!)
void verifyBBInRegion(BlockT *BB) const;
/// Walk over all the BBs of the region starting from BB and
/// verify that all reachable basic blocks are elements of the region.
/// (EXPENSIVE!)
void verifyWalk(BlockT *BB, std::set<BlockT *> *visitedBB) const;
/// Verify if the region and its children are valid regions (EXPENSIVE!)
void verifyRegionNest() const;
public:
/// Create a new region.
///
/// @param Entry The entry basic block of the region.
/// @param Exit The exit basic block of the region.
/// @param RI The region info object that is managing this region.
/// @param DT The dominator tree of the current function.
/// @param Parent The surrounding region or NULL if this is a top level
/// region.
RegionBase(BlockT *Entry, BlockT *Exit, RegionInfoT *RI, DomTreeT *DT,
RegionT *Parent = nullptr);
RegionBase(const RegionBase &) = delete;
RegionBase &operator=(const RegionBase &) = delete;
/// Delete the Region and all its subregions.
~RegionBase();
/// Get the entry BasicBlock of the Region.
/// @return The entry BasicBlock of the region.
BlockT *getEntry() const {
return RegionNodeBase<Tr>::getEntry();
}
/// Replace the entry basic block of the region with the new basic
/// block.
///
/// @param BB The new entry basic block of the region.
void replaceEntry(BlockT *BB);
/// Replace the exit basic block of the region with the new basic
/// block.
///
/// @param BB The new exit basic block of the region.
void replaceExit(BlockT *BB);
/// Recursively replace the entry basic block of the region.
///
/// This function replaces the entry basic block with a new basic block. It
/// also updates all child regions that have the same entry basic block as
/// this region.
///
/// @param NewEntry The new entry basic block.
void replaceEntryRecursive(BlockT *NewEntry);
/// Recursively replace the exit basic block of the region.
///
/// This function replaces the exit basic block with a new basic block. It
/// also updates all child regions that have the same exit basic block as
/// this region.
///
/// @param NewExit The new exit basic block.
void replaceExitRecursive(BlockT *NewExit);
/// Get the exit BasicBlock of the Region.
/// @return The exit BasicBlock of the Region, NULL if this is the TopLevel
/// Region.
BlockT *getExit() const { return exit; }
/// Get the parent of the Region.
/// @return The parent of the Region or NULL if this is a top level
/// Region.
RegionT *getParent() const {
return RegionNodeBase<Tr>::getParent();
}
/// Get the RegionNode representing the current Region.
/// @return The RegionNode representing the current Region.
RegionNodeT *getNode() const {
return const_cast<RegionNodeT *>(
reinterpret_cast<const RegionNodeT *>(this));
}
/// Get the nesting level of this Region.
///
/// An toplevel Region has depth 0.
///
/// @return The depth of the region.
unsigned getDepth() const;
/// Check if a Region is the TopLevel region.
///
/// The toplevel region represents the whole function.
bool isTopLevelRegion() const { return exit == nullptr; }
/// Return a new (non-canonical) region, that is obtained by joining
/// this region with its predecessors.
///
/// @return A region also starting at getEntry(), but reaching to the next
/// basic block that forms with getEntry() a (non-canonical) region.
/// NULL if such a basic block does not exist.
RegionT *getExpandedRegion() const;
/// Return the first block of this region's single entry edge,
/// if existing.
///
/// @return The BasicBlock starting this region's single entry edge,
/// else NULL.
BlockT *getEnteringBlock() const;
/// Return the first block of this region's single exit edge,
/// if existing.
///
/// @return The BasicBlock starting this region's single exit edge,
/// else NULL.
BlockT *getExitingBlock() const;
/// Collect all blocks of this region's single exit edge, if existing.
///
/// @return True if this region contains all the predecessors of the exit.
bool getExitingBlocks(SmallVectorImpl<BlockT *> &Exitings) const;
/// Is this a simple region?
///
/// A region is simple if it has exactly one exit and one entry edge.
///
/// @return True if the Region is simple.
bool isSimple() const;
/// Returns the name of the Region.
/// @return The Name of the Region.
std::string getNameStr() const;
/// Return the RegionInfo object, that belongs to this Region.
RegionInfoT *getRegionInfo() const { return RI; }
/// PrintStyle - Print region in difference ways.
enum PrintStyle { PrintNone, PrintBB, PrintRN };
/// Print the region.
///
/// @param OS The output stream the Region is printed to.
/// @param printTree Print also the tree of subregions.
/// @param level The indentation level used for printing.
void print(raw_ostream &OS, bool printTree = true, unsigned level = 0,
PrintStyle Style = PrintNone) const;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Print the region to stderr.
void dump() const;
#endif
/// Check if the region contains a BasicBlock.
///
/// @param BB The BasicBlock that might be contained in this Region.
/// @return True if the block is contained in the region otherwise false.
bool contains(const BlockT *BB) const;
/// Check if the region contains another region.
///
/// @param SubRegion The region that might be contained in this Region.
/// @return True if SubRegion is contained in the region otherwise false.
bool contains(const RegionT *SubRegion) const {
// Toplevel Region.
if (!getExit())
return true;
return contains(SubRegion->getEntry()) &&
(contains(SubRegion->getExit()) ||
SubRegion->getExit() == getExit());
}
/// Check if the region contains an Instruction.
///
/// @param Inst The Instruction that might be contained in this region.
/// @return True if the Instruction is contained in the region otherwise
/// false.
bool contains(const InstT *Inst) const { return contains(Inst->getParent()); }
/// Check if the region contains a loop.
///
/// @param L The loop that might be contained in this region.
/// @return True if the loop is contained in the region otherwise false.
/// In case a NULL pointer is passed to this function the result
/// is false, except for the region that describes the whole function.
/// In that case true is returned.
bool contains(const LoopT *L) const;
/// Get the outermost loop in the region that contains a loop.
///
/// Find for a Loop L the outermost loop OuterL that is a parent loop of L
/// and is itself contained in the region.
///
/// @param L The loop the lookup is started.
/// @return The outermost loop in the region, NULL if such a loop does not
/// exist or if the region describes the whole function.
LoopT *outermostLoopInRegion(LoopT *L) const;
/// Get the outermost loop in the region that contains a basic block.
///
/// Find for a basic block BB the outermost loop L that contains BB and is
/// itself contained in the region.
///
/// @param LI A pointer to a LoopInfo analysis.
/// @param BB The basic block surrounded by the loop.
/// @return The outermost loop in the region, NULL if such a loop does not
/// exist or if the region describes the whole function.
LoopT *outermostLoopInRegion(LoopInfoT *LI, BlockT *BB) const;
/// Get the subregion that starts at a BasicBlock
///
/// @param BB The BasicBlock the subregion should start.
/// @return The Subregion if available, otherwise NULL.
RegionT *getSubRegionNode(BlockT *BB) const;
/// Get the RegionNode for a BasicBlock
///
/// @param BB The BasicBlock at which the RegionNode should start.
/// @return If available, the RegionNode that represents the subregion
/// starting at BB. If no subregion starts at BB, the RegionNode
/// representing BB.
RegionNodeT *getNode(BlockT *BB) const;
/// Get the BasicBlock RegionNode for a BasicBlock
///
/// @param BB The BasicBlock for which the RegionNode is requested.
/// @return The RegionNode representing the BB.
RegionNodeT *getBBNode(BlockT *BB) const;
/// Add a new subregion to this Region.
///
/// @param SubRegion The new subregion that will be added.
/// @param moveChildren Move the children of this region, that are also
/// contained in SubRegion into SubRegion.
void addSubRegion(RegionT *SubRegion, bool moveChildren = false);
/// Remove a subregion from this Region.
///
/// The subregion is not deleted, as it will probably be inserted into another
/// region.
/// @param SubRegion The SubRegion that will be removed.
RegionT *removeSubRegion(RegionT *SubRegion);
/// Move all direct child nodes of this Region to another Region.
///
/// @param To The Region the child nodes will be transferred to.
void transferChildrenTo(RegionT *To);
/// Verify if the region is a correct region.
///
/// Check if this is a correctly build Region. This is an expensive check, as
/// the complete CFG of the Region will be walked.
void verifyRegion() const;
/// Clear the cache for BB RegionNodes.
///
/// After calling this function the BasicBlock RegionNodes will be stored at
/// different memory locations. RegionNodes obtained before this function is
/// called are therefore not comparable to RegionNodes abtained afterwords.
void clearNodeCache();
/// @name Subregion Iterators
///
/// These iterators iterator over all subregions of this Region.
//@{
using iterator = typename RegionSet::iterator;
using const_iterator = typename RegionSet::const_iterator;
iterator begin() { return children.begin(); }
iterator end() { return children.end(); }
const_iterator begin() const { return children.begin(); }
const_iterator end() const { return children.end(); }
//@}
/// @name BasicBlock Iterators
///
/// These iterators iterate over all BasicBlocks that are contained in this
/// Region. The iterator also iterates over BasicBlocks that are elements of
/// a subregion of this Region. It is therefore called a flat iterator.
//@{
template <bool IsConst>
class block_iterator_wrapper
: public df_iterator<
typename std::conditional<IsConst, const BlockT, BlockT>::type *> {
using super =
df_iterator<
typename std::conditional<IsConst, const BlockT, BlockT>::type *>;
public:
using Self = block_iterator_wrapper<IsConst>;
using value_type = typename super::value_type;
// Construct the begin iterator.
block_iterator_wrapper(value_type Entry, value_type Exit)
: super(df_begin(Entry)) {
// Mark the exit of the region as visited, so that the children of the
// exit and the exit itself, i.e. the block outside the region will never
// be visited.
super::Visited.insert(Exit);
}
// Construct the end iterator.
block_iterator_wrapper() : super(df_end<value_type>((BlockT *)nullptr)) {}
/*implicit*/ block_iterator_wrapper(super I) : super(I) {}
// FIXME: Even a const_iterator returns a non-const BasicBlock pointer.
// This was introduced for backwards compatibility, but should
// be removed as soon as all users are fixed.
BlockT *operator*() const {
return const_cast<BlockT *>(super::operator*());
}
};
using block_iterator = block_iterator_wrapper<false>;
using const_block_iterator = block_iterator_wrapper<true>;
block_iterator block_begin() { return block_iterator(getEntry(), getExit()); }
block_iterator block_end() { return block_iterator(); }
const_block_iterator block_begin() const {
return const_block_iterator(getEntry(), getExit());
}
const_block_iterator block_end() const { return const_block_iterator(); }
using block_range = iterator_range<block_iterator>;
using const_block_range = iterator_range<const_block_iterator>;
/// Returns a range view of the basic blocks in the region.
inline block_range blocks() {
return block_range(block_begin(), block_end());
}
/// Returns a range view of the basic blocks in the region.
///
/// This is the 'const' version of the range view.
inline const_block_range blocks() const {
return const_block_range(block_begin(), block_end());
}
//@}
/// @name Element Iterators
///
/// These iterators iterate over all BasicBlock and subregion RegionNodes that
/// are direct children of this Region. It does not iterate over any
/// RegionNodes that are also element of a subregion of this Region.
//@{
using element_iterator =
df_iterator<RegionNodeT *, df_iterator_default_set<RegionNodeT *>, false,
GraphTraits<RegionNodeT *>>;
using const_element_iterator =
df_iterator<const RegionNodeT *,
df_iterator_default_set<const RegionNodeT *>, false,
GraphTraits<const RegionNodeT *>>;
element_iterator element_begin();
element_iterator element_end();
iterator_range<element_iterator> elements() {
return make_range(element_begin(), element_end());
}
const_element_iterator element_begin() const;
const_element_iterator element_end() const;
iterator_range<const_element_iterator> elements() const {
return make_range(element_begin(), element_end());
}
//@}
};
/// Print a RegionNode.
template <class Tr>
inline raw_ostream &operator<<(raw_ostream &OS, const RegionNodeBase<Tr> &Node);
//===----------------------------------------------------------------------===//
/// Analysis that detects all canonical Regions.
///
/// The RegionInfo pass detects all canonical regions in a function. The Regions
/// are connected using the parent relation. This builds a Program Structure
/// Tree.
template <class Tr>
class RegionInfoBase {
friend class RegionInfo;
friend class MachineRegionInfo;
using BlockT = typename Tr::BlockT;
using FuncT = typename Tr::FuncT;
using RegionT = typename Tr::RegionT;
using RegionInfoT = typename Tr::RegionInfoT;
using DomTreeT = typename Tr::DomTreeT;
using DomTreeNodeT = typename Tr::DomTreeNodeT;
using PostDomTreeT = typename Tr::PostDomTreeT;
using DomFrontierT = typename Tr::DomFrontierT;
using BlockTraits = GraphTraits<BlockT *>;
using InvBlockTraits = GraphTraits<Inverse<BlockT *>>;
using SuccIterTy = typename BlockTraits::ChildIteratorType;
using PredIterTy = typename InvBlockTraits::ChildIteratorType;
using BBtoBBMap = DenseMap<BlockT *, BlockT *>;
using BBtoRegionMap = DenseMap<BlockT *, RegionT *>;
RegionInfoBase();
RegionInfoBase(RegionInfoBase &&Arg)
: DT(std::move(Arg.DT)), PDT(std::move(Arg.PDT)), DF(std::move(Arg.DF)),
TopLevelRegion(std::move(Arg.TopLevelRegion)),
BBtoRegion(std::move(Arg.BBtoRegion)) {
Arg.wipe();
}
RegionInfoBase &operator=(RegionInfoBase &&RHS) {
DT = std::move(RHS.DT);
PDT = std::move(RHS.PDT);
DF = std::move(RHS.DF);
TopLevelRegion = std::move(RHS.TopLevelRegion);
BBtoRegion = std::move(RHS.BBtoRegion);
RHS.wipe();
return *this;
}
virtual ~RegionInfoBase();
DomTreeT *DT;
PostDomTreeT *PDT;
DomFrontierT *DF;
/// The top level region.
RegionT *TopLevelRegion = nullptr;
/// Map every BB to the smallest region, that contains BB.
BBtoRegionMap BBtoRegion;
protected:
/// Update refences to a RegionInfoT held by the RegionT managed here
///
/// This is a post-move helper. Regions hold references to the owning
/// RegionInfo object. After a move these need to be fixed.
template<typename TheRegionT>
void updateRegionTree(RegionInfoT &RI, TheRegionT *R) {
if (!R)
return;
R->RI = &RI;
for (auto &SubR : *R)
updateRegionTree(RI, SubR.get());
}
private:
/// Wipe this region tree's state without releasing any resources.
///
/// This is essentially a post-move helper only. It leaves the object in an
/// assignable and destroyable state, but otherwise invalid.
void wipe() {
DT = nullptr;
PDT = nullptr;
DF = nullptr;
TopLevelRegion = nullptr;
BBtoRegion.clear();
}
// Check whether the entries of BBtoRegion for the BBs of region
// SR are correct. Triggers an assertion if not. Calls itself recursively for
// subregions.
void verifyBBMap(const RegionT *SR) const;
// Returns true if BB is in the dominance frontier of
// entry, because it was inherited from exit. In the other case there is an
// edge going from entry to BB without passing exit.
bool isCommonDomFrontier(BlockT *BB, BlockT *entry, BlockT *exit) const;
// Check if entry and exit surround a valid region, based on
// dominance tree and dominance frontier.
bool isRegion(BlockT *entry, BlockT *exit) const;
// Saves a shortcut pointing from entry to exit.
// This function may extend this shortcut if possible.
void insertShortCut(BlockT *entry, BlockT *exit, BBtoBBMap *ShortCut) const;
// Returns the next BB that postdominates N, while skipping
// all post dominators that cannot finish a canonical region.
DomTreeNodeT *getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const;
// A region is trivial, if it contains only one BB.
bool isTrivialRegion(BlockT *entry, BlockT *exit) const;
// Creates a single entry single exit region.
RegionT *createRegion(BlockT *entry, BlockT *exit);
// Detect all regions starting with bb 'entry'.
void findRegionsWithEntry(BlockT *entry, BBtoBBMap *ShortCut);
// Detects regions in F.
void scanForRegions(FuncT &F, BBtoBBMap *ShortCut);
// Get the top most parent with the same entry block.
RegionT *getTopMostParent(RegionT *region);
// Build the region hierarchy after all region detected.
void buildRegionsTree(DomTreeNodeT *N, RegionT *region);
// Update statistic about created regions.
virtual void updateStatistics(RegionT *R) = 0;
// Detect all regions in function and build the region tree.
void calculate(FuncT &F);
public:
RegionInfoBase(const RegionInfoBase &) = delete;
RegionInfoBase &operator=(const RegionInfoBase &) = delete;
static bool VerifyRegionInfo;
static typename RegionT::PrintStyle printStyle;
void print(raw_ostream &OS) const;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void dump() const;
#endif
void releaseMemory();
/// Get the smallest region that contains a BasicBlock.
///
/// @param BB The basic block.
/// @return The smallest region, that contains BB or NULL, if there is no
/// region containing BB.
RegionT *getRegionFor(BlockT *BB) const;
/// Set the smallest region that surrounds a basic block.
///
/// @param BB The basic block surrounded by a region.
/// @param R The smallest region that surrounds BB.
void setRegionFor(BlockT *BB, RegionT *R);
/// A shortcut for getRegionFor().
///
/// @param BB The basic block.
/// @return The smallest region, that contains BB or NULL, if there is no
/// region containing BB.
RegionT *operator[](BlockT *BB) const;
/// Return the exit of the maximal refined region, that starts at a
/// BasicBlock.
///
/// @param BB The BasicBlock the refined region starts.
BlockT *getMaxRegionExit(BlockT *BB) const;
/// Find the smallest region that contains two regions.
///
/// @param A The first region.
/// @param B The second region.
/// @return The smallest region containing A and B.
RegionT *getCommonRegion(RegionT *A, RegionT *B) const;
/// Find the smallest region that contains two basic blocks.
///
/// @param A The first basic block.
/// @param B The second basic block.
/// @return The smallest region that contains A and B.
RegionT *getCommonRegion(BlockT *A, BlockT *B) const {
return getCommonRegion(getRegionFor(A), getRegionFor(B));
}
/// Find the smallest region that contains a set of regions.
///
/// @param Regions A vector of regions.
/// @return The smallest region that contains all regions in Regions.
RegionT *getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const;
/// Find the smallest region that contains a set of basic blocks.
///
/// @param BBs A vector of basic blocks.
/// @return The smallest region that contains all basic blocks in BBS.
RegionT *getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const;
RegionT *getTopLevelRegion() const { return TopLevelRegion; }
/// Clear the Node Cache for all Regions.
///
/// @see Region::clearNodeCache()
void clearNodeCache() {
if (TopLevelRegion)
TopLevelRegion->clearNodeCache();
}
void verifyAnalysis() const;
};
class Region;
class RegionNode : public RegionNodeBase<RegionTraits<Function>> {
public:
inline RegionNode(Region *Parent, BasicBlock *Entry, bool isSubRegion = false)
: RegionNodeBase<RegionTraits<Function>>(Parent, Entry, isSubRegion) {}
bool operator==(const Region &RN) const {
return this == reinterpret_cast<const RegionNode *>(&RN);
}
};
class Region : public RegionBase<RegionTraits<Function>> {
public:
Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo *RI, DominatorTree *DT,
Region *Parent = nullptr);
~Region();
bool operator==(const RegionNode &RN) const {
return &RN == reinterpret_cast<const RegionNode *>(this);
}
};
class RegionInfo : public RegionInfoBase<RegionTraits<Function>> {
public:
using Base = RegionInfoBase<RegionTraits<Function>>;
explicit RegionInfo();
RegionInfo(RegionInfo &&Arg) : Base(std::move(static_cast<Base &>(Arg))) {
updateRegionTree(*this, TopLevelRegion);
}
RegionInfo &operator=(RegionInfo &&RHS) {
Base::operator=(std::move(static_cast<Base &>(RHS)));
updateRegionTree(*this, TopLevelRegion);
return *this;
}
~RegionInfo() override;
/// Handle invalidation explicitly.
bool invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &);
// updateStatistics - Update statistic about created regions.
void updateStatistics(Region *R) final;
void recalculate(Function &F, DominatorTree *DT, PostDominatorTree *PDT,
DominanceFrontier *DF);
#ifndef NDEBUG
/// Opens a viewer to show the GraphViz visualization of the regions.
///
/// Useful during debugging as an alternative to dump().
void view();
/// Opens a viewer to show the GraphViz visualization of this region
/// without instructions in the BasicBlocks.
///
/// Useful during debugging as an alternative to dump().
void viewOnly();
#endif
};
class RegionInfoPass : public FunctionPass {
RegionInfo RI;
public:
static char ID;
explicit RegionInfoPass();
~RegionInfoPass() override;
RegionInfo &getRegionInfo() { return RI; }
const RegionInfo &getRegionInfo() const { return RI; }
/// @name FunctionPass interface
//@{
bool runOnFunction(Function &F) override;
void releaseMemory() override;
void verifyAnalysis() const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
void print(raw_ostream &OS, const Module *) const override;
void dump() const;
//@}
};
/// Analysis pass that exposes the \c RegionInfo for a function.
class RegionInfoAnalysis : public AnalysisInfoMixin<RegionInfoAnalysis> {
friend AnalysisInfoMixin<RegionInfoAnalysis>;
static AnalysisKey Key;
public:
using Result = RegionInfo;
RegionInfo run(Function &F, FunctionAnalysisManager &AM);
};
/// Printer pass for the \c RegionInfo.
class RegionInfoPrinterPass : public PassInfoMixin<RegionInfoPrinterPass> {
raw_ostream &OS;
public:
explicit RegionInfoPrinterPass(raw_ostream &OS);
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
/// Verifier pass for the \c RegionInfo.
struct RegionInfoVerifierPass : PassInfoMixin<RegionInfoVerifierPass> {
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
template <>
template <>
inline BasicBlock *
RegionNodeBase<RegionTraits<Function>>::getNodeAs<BasicBlock>() const {
assert(!isSubRegion() && "This is not a BasicBlock RegionNode!");
return getEntry();
}
template <>
template <>
inline Region *
RegionNodeBase<RegionTraits<Function>>::getNodeAs<Region>() const {
assert(isSubRegion() && "This is not a subregion RegionNode!");
auto Unconst = const_cast<RegionNodeBase<RegionTraits<Function>> *>(this);
return reinterpret_cast<Region *>(Unconst);
}
template <class Tr>
inline raw_ostream &operator<<(raw_ostream &OS,
const RegionNodeBase<Tr> &Node) {
using BlockT = typename Tr::BlockT;
using RegionT = typename Tr::RegionT;
if (Node.isSubRegion())
return OS << Node.template getNodeAs<RegionT>()->getNameStr();
else
return OS << Node.template getNodeAs<BlockT>()->getName();
}
extern template class RegionBase<RegionTraits<Function>>;
extern template class RegionNodeBase<RegionTraits<Function>>;
extern template class RegionInfoBase<RegionTraits<Function>>;
} // end namespace llvm
#endif // LLVM_ANALYSIS_REGIONINFO_H