6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
362 lines
12 KiB
C++
362 lines
12 KiB
C++
//==- llvm/CodeGen/MachineDominators.h - Machine Dom Calculation -*- C++ -*-==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines classes mirroring those in llvm/Analysis/Dominators.h,
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// but for target-specific code rather than target-independent IR.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_MACHINEDOMINATORS_H
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#define LLVM_CODEGEN_MACHINEDOMINATORS_H
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineInstrBundleIterator.h"
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#include "llvm/CodeGen/MachinePassManager.h"
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#include "llvm/Support/GenericDomTree.h"
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#include <cassert>
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#include <memory>
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#include <optional>
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namespace llvm {
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class AnalysisUsage;
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class MachineFunction;
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class Module;
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class raw_ostream;
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template <>
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inline void DominatorTreeBase<MachineBasicBlock, false>::addRoot(
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MachineBasicBlock *MBB) {
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this->Roots.push_back(MBB);
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}
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extern template class DomTreeNodeBase<MachineBasicBlock>;
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extern template class DominatorTreeBase<MachineBasicBlock, false>; // DomTree
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using MachineDomTreeNode = DomTreeNodeBase<MachineBasicBlock>;
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namespace DomTreeBuilder {
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using MBBDomTree = DomTreeBase<MachineBasicBlock>;
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using MBBUpdates = ArrayRef<llvm::cfg::Update<MachineBasicBlock *>>;
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using MBBDomTreeGraphDiff = GraphDiff<MachineBasicBlock *, false>;
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extern template void Calculate<MBBDomTree>(MBBDomTree &DT);
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extern template void CalculateWithUpdates<MBBDomTree>(MBBDomTree &DT,
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MBBUpdates U);
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extern template void InsertEdge<MBBDomTree>(MBBDomTree &DT,
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MachineBasicBlock *From,
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MachineBasicBlock *To);
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extern template void DeleteEdge<MBBDomTree>(MBBDomTree &DT,
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MachineBasicBlock *From,
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MachineBasicBlock *To);
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extern template void ApplyUpdates<MBBDomTree>(MBBDomTree &DT,
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MBBDomTreeGraphDiff &,
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MBBDomTreeGraphDiff *);
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extern template bool Verify<MBBDomTree>(const MBBDomTree &DT,
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MBBDomTree::VerificationLevel VL);
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} // namespace DomTreeBuilder
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//===-------------------------------------
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/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
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/// compute a normal dominator tree.
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///
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class MachineDominatorTree : public DomTreeBase<MachineBasicBlock> {
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/// Helper structure used to hold all the basic blocks
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/// involved in the split of a critical edge.
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struct CriticalEdge {
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MachineBasicBlock *FromBB;
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MachineBasicBlock *ToBB;
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MachineBasicBlock *NewBB;
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};
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/// Pile up all the critical edges to be split.
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/// The splitting of a critical edge is local and thus, it is possible
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/// to apply several of those changes at the same time.
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mutable SmallVector<CriticalEdge, 32> CriticalEdgesToSplit;
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/// Remember all the basic blocks that are inserted during
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/// edge splitting.
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/// Invariant: NewBBs == all the basic blocks contained in the NewBB
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/// field of all the elements of CriticalEdgesToSplit.
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/// I.e., forall elt in CriticalEdgesToSplit, it exists BB in NewBBs
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/// such as BB == elt.NewBB.
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mutable SmallSet<MachineBasicBlock *, 32> NewBBs;
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/// Apply all the recorded critical edges to the DT.
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/// This updates the underlying DT information in a way that uses
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/// the fast query path of DT as much as possible.
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/// FIXME: This method should not be a const member!
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///
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/// \post CriticalEdgesToSplit.empty().
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void applySplitCriticalEdges() const;
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public:
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using Base = DomTreeBase<MachineBasicBlock>;
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MachineDominatorTree() = default;
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explicit MachineDominatorTree(MachineFunction &MF) { calculate(MF); }
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/// Handle invalidation explicitly.
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bool invalidate(MachineFunction &, const PreservedAnalyses &PA,
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MachineFunctionAnalysisManager::Invalidator &);
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// FIXME: If there is an updater for MachineDominatorTree,
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// migrate to this updater and remove these wrappers.
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MachineDominatorTree &getBase() {
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applySplitCriticalEdges();
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return *this;
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}
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MachineBasicBlock *getRoot() const {
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applySplitCriticalEdges();
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return Base::getRoot();
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}
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MachineDomTreeNode *getRootNode() const {
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applySplitCriticalEdges();
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return const_cast<MachineDomTreeNode *>(Base::getRootNode());
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}
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void calculate(MachineFunction &F);
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bool dominates(const MachineDomTreeNode *A,
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const MachineDomTreeNode *B) const {
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applySplitCriticalEdges();
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return Base::dominates(A, B);
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}
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void getDescendants(MachineBasicBlock *A,
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SmallVectorImpl<MachineBasicBlock *> &Result) {
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applySplitCriticalEdges();
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Base::getDescendants(A, Result);
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}
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bool dominates(const MachineBasicBlock *A, const MachineBasicBlock *B) const {
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applySplitCriticalEdges();
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return Base::dominates(A, B);
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}
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// dominates - Return true if A dominates B. This performs the
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// special checks necessary if A and B are in the same basic block.
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bool dominates(const MachineInstr *A, const MachineInstr *B) const {
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applySplitCriticalEdges();
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const MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
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if (BBA != BBB)
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return Base::dominates(BBA, BBB);
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// Loop through the basic block until we find A or B.
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MachineBasicBlock::const_iterator I = BBA->begin();
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for (; &*I != A && &*I != B; ++I)
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/*empty*/ ;
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return &*I == A;
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}
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bool properlyDominates(const MachineDomTreeNode *A,
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const MachineDomTreeNode *B) const {
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applySplitCriticalEdges();
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return Base::properlyDominates(A, B);
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}
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bool properlyDominates(const MachineBasicBlock *A,
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const MachineBasicBlock *B) const {
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applySplitCriticalEdges();
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return Base::properlyDominates(A, B);
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}
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/// findNearestCommonDominator - Find nearest common dominator basic block
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/// for basic block A and B. If there is no such block then return NULL.
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MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
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MachineBasicBlock *B) {
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applySplitCriticalEdges();
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return Base::findNearestCommonDominator(A, B);
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}
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MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
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applySplitCriticalEdges();
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return Base::getNode(BB);
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}
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/// getNode - return the (Post)DominatorTree node for the specified basic
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/// block. This is the same as using operator[] on this class.
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///
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MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
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applySplitCriticalEdges();
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return Base::getNode(BB);
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}
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/// addNewBlock - Add a new node to the dominator tree information. This
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/// creates a new node as a child of DomBB dominator node,linking it into
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/// the children list of the immediate dominator.
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MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
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MachineBasicBlock *DomBB) {
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applySplitCriticalEdges();
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return Base::addNewBlock(BB, DomBB);
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}
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/// changeImmediateDominator - This method is used to update the dominator
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/// tree information when a node's immediate dominator changes.
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///
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void changeImmediateDominator(MachineBasicBlock *N,
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MachineBasicBlock *NewIDom) {
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applySplitCriticalEdges();
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Base::changeImmediateDominator(N, NewIDom);
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}
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void changeImmediateDominator(MachineDomTreeNode *N,
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MachineDomTreeNode *NewIDom) {
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applySplitCriticalEdges();
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Base::changeImmediateDominator(N, NewIDom);
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}
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/// eraseNode - Removes a node from the dominator tree. Block must not
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/// dominate any other blocks. Removes node from its immediate dominator's
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/// children list. Deletes dominator node associated with basic block BB.
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void eraseNode(MachineBasicBlock *BB) {
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applySplitCriticalEdges();
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Base::eraseNode(BB);
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}
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/// splitBlock - BB is split and now it has one successor. Update dominator
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/// tree to reflect this change.
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void splitBlock(MachineBasicBlock* NewBB) {
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applySplitCriticalEdges();
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Base::splitBlock(NewBB);
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}
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/// isReachableFromEntry - Return true if A is dominated by the entry
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/// block of the function containing it.
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bool isReachableFromEntry(const MachineBasicBlock *A) {
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applySplitCriticalEdges();
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return Base::isReachableFromEntry(A);
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}
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/// Record that the critical edge (FromBB, ToBB) has been
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/// split with NewBB.
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/// This is best to use this method instead of directly update the
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/// underlying information, because this helps mitigating the
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/// number of time the DT information is invalidated.
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///
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/// \note Do not use this method with regular edges.
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///
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/// \note To benefit from the compile time improvement incurred by this
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/// method, the users of this method have to limit the queries to the DT
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/// interface between two edges splitting. In other words, they have to
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/// pack the splitting of critical edges as much as possible.
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void recordSplitCriticalEdge(MachineBasicBlock *FromBB,
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MachineBasicBlock *ToBB,
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MachineBasicBlock *NewBB) {
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bool Inserted = NewBBs.insert(NewBB).second;
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(void)Inserted;
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assert(Inserted &&
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"A basic block inserted via edge splitting cannot appear twice");
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CriticalEdgesToSplit.push_back({FromBB, ToBB, NewBB});
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}
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};
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/// \brief Analysis pass which computes a \c MachineDominatorTree.
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class MachineDominatorTreeAnalysis
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: public AnalysisInfoMixin<MachineDominatorTreeAnalysis> {
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friend AnalysisInfoMixin<MachineDominatorTreeAnalysis>;
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static AnalysisKey Key;
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public:
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using Result = MachineDominatorTree;
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Result run(MachineFunction &MF, MachineFunctionAnalysisManager &);
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};
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/// \brief Machine function pass which print \c MachineDominatorTree.
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class MachineDominatorTreePrinterPass
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: public PassInfoMixin<MachineDominatorTreePrinterPass> {
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raw_ostream &OS;
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public:
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explicit MachineDominatorTreePrinterPass(raw_ostream &OS) : OS(OS) {}
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PreservedAnalyses run(MachineFunction &MF,
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MachineFunctionAnalysisManager &MFAM);
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static bool isRequired() { return true; }
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};
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/// \brief Analysis pass which computes a \c MachineDominatorTree.
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class MachineDominatorTreeWrapperPass : public MachineFunctionPass {
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// MachineFunctionPass may verify the analysis result without running pass,
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// e.g. when `F.hasAvailableExternallyLinkage` is true.
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std::optional<MachineDominatorTree> DT;
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public:
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static char ID;
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MachineDominatorTreeWrapperPass();
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MachineDominatorTree &getDomTree() { return *DT; }
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const MachineDominatorTree &getDomTree() const { return *DT; }
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bool runOnMachineFunction(MachineFunction &MF) override;
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void verifyAnalysis() const override;
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesAll();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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void releaseMemory() override;
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void print(raw_ostream &OS, const Module *M = nullptr) const override;
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};
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//===-------------------------------------
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/// DominatorTree GraphTraits specialization so the DominatorTree can be
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/// iterable by generic graph iterators.
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///
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template <class Node, class ChildIterator>
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struct MachineDomTreeGraphTraitsBase {
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using NodeRef = Node *;
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using ChildIteratorType = ChildIterator;
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static NodeRef getEntryNode(NodeRef N) { return N; }
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static ChildIteratorType child_begin(NodeRef N) { return N->begin(); }
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static ChildIteratorType child_end(NodeRef N) { return N->end(); }
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};
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template <class T> struct GraphTraits;
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template <>
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struct GraphTraits<MachineDomTreeNode *>
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: public MachineDomTreeGraphTraitsBase<MachineDomTreeNode,
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MachineDomTreeNode::const_iterator> {
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};
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template <>
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struct GraphTraits<const MachineDomTreeNode *>
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: public MachineDomTreeGraphTraitsBase<const MachineDomTreeNode,
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MachineDomTreeNode::const_iterator> {
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};
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template <> struct GraphTraits<MachineDominatorTree*>
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: public GraphTraits<MachineDomTreeNode *> {
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static NodeRef getEntryNode(MachineDominatorTree *DT) {
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return DT->getRootNode();
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}
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};
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} // end namespace llvm
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#endif // LLVM_CODEGEN_MACHINEDOMINATORS_H
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