Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree. More...

#include "llvm/IR/Dominators.h"

Inheritance diagram for llvm::DominatorTree:

Collaboration diagram for llvm::DominatorTree:

[legend]

Public Types
using	Base = DominatorTreeBase< BasicBlock, false >

Public Types inherited from llvm::DominatorTreeBase< BasicBlock, false >
enum	VerificationLevel

using	NodeTrait = DomTreeNodeTraits< BasicBlock >

using	NodeType = typename NodeTrait::NodeType

using	NodePtr = typename NodeTrait::NodePtr

using	ParentPtr = typename NodeTrait::ParentPtr

using	ParentType = std::remove_pointer_t< ParentPtr >

using	UpdateType = cfg::Update< NodePtr >

using	UpdateKind = cfg::UpdateKind

using	root_iterator = typename SmallVectorImpl< BasicBlock * >::iterator
	Iteration over roots.

using	const_root_iterator = typename SmallVectorImpl< BasicBlock * >::const_iterator

Public Member Functions
	DominatorTree ()=default

	DominatorTree (Function &F)

	DominatorTree (DominatorTree &DT, DomTreeBuilder::BBUpdates U)

bool	invalidate (Function &F, const PreservedAnalyses &PA, FunctionAnalysisManager::Invalidator &)
	Handle invalidation explicitly.

bool	dominates (const BasicBlock *BB, const Use &U) const
	Return true if the (end of the) basic block BB dominates the use U.

bool	dominates (const Value *Def, const Use &U) const
	Return true if value Def dominates use U, in the sense that Def is available at U, and could be substituted as the used value without violating the SSA dominance requirement.

bool	dominates (const Value Def, const Instruction User) const
	Return true if value Def dominates all possible uses inside instruction User.

bool	dominates (const Instruction Def, const BasicBlock BB) const
	Returns true if Def would dominate a use in any instruction in BB.

bool	dominates (const BasicBlockEdge &BBE, const Use &U) const
	Return true if an edge dominates a use.

bool	dominates (const BasicBlockEdge &BBE, const BasicBlock *BB) const

bool	dominates (const BasicBlockEdge &BBE1, const BasicBlockEdge &BBE2) const
	Returns true if edge `BBE1` dominates edge `BBE2`.

bool	isReachableFromEntry (const Use &U) const
	Provide an overload for a Use.

Instruction *	findNearestCommonDominator (Instruction I1, Instruction I2) const
	Find the nearest instruction I that dominates both I1 and I2, in the sense that a result produced before I will be available at both I1 and I2.

void	viewGraph (const Twine &Name, const Twine &Title)

void	viewGraph ()

Public Member Functions inherited from llvm::DominatorTreeBase< BasicBlock, false >
	DominatorTreeBase ()=default

	DominatorTreeBase (DominatorTreeBase &&Arg)

	DominatorTreeBase (const DominatorTreeBase &)=delete

DominatorTreeBase &	operator= (DominatorTreeBase &&RHS)

DominatorTreeBase &	operator= (const DominatorTreeBase &)=delete

root_iterator	root_begin ()

const_root_iterator	root_begin () const

root_iterator	root_end ()

const_root_iterator	root_end () const

size_t	root_size () const

iterator_range< root_iterator >	roots ()

iterator_range< const_root_iterator >	roots () const

bool	isPostDominator () const
	isPostDominator - Returns true if analysis based of postdoms

bool	compare (const DominatorTreeBase &Other) const
	compare - Return false if the other dominator tree base matches this dominator tree base.

DomTreeNodeBase< BasicBlock > *	getNode (const BasicBlock *BB) const
	getNode - return the (Post)DominatorTree node for the specified basic block.

DomTreeNodeBase< BasicBlock > *	operator[] (const BasicBlock *BB) const
	See getNode.

DomTreeNodeBase< BasicBlock > *	getRootNode ()
	getRootNode - This returns the entry node for the CFG of the function.

const DomTreeNodeBase< BasicBlock > *	getRootNode () const

void	getDescendants (BasicBlock R, SmallVectorImpl< BasicBlock > &Result) const
	Get all nodes dominated by R, including R itself.

bool	properlyDominates (const DomTreeNodeBase< BasicBlock > A, const DomTreeNodeBase< BasicBlock > B) const
	properlyDominates - Returns true iff A dominates B and A != B.

bool	properlyDominates (const BasicBlock A, const BasicBlock B) const

bool	isReachableFromEntry (const BasicBlock *A) const
	isReachableFromEntry - Return true if A is dominated by the entry block of the function containing it.

bool	isReachableFromEntry (const DomTreeNodeBase< BasicBlock > *A) const

bool	dominates (const DomTreeNodeBase< BasicBlock > A, const DomTreeNodeBase< BasicBlock > B) const
	dominates - Returns true iff A dominates B.

bool	dominates (const BasicBlock A, const BasicBlock B) const

BasicBlock *	getRoot () const

BasicBlock *	findNearestCommonDominator (BasicBlock A, BasicBlock B) const
	Find nearest common dominator basic block for basic block A and B.

const BasicBlock *	findNearestCommonDominator (const BasicBlock A, const BasicBlock B) const

bool	isVirtualRoot (const DomTreeNodeBase< BasicBlock > *A) const

void	applyUpdates (ArrayRef< UpdateType > Updates)
	Inform the dominator tree about a sequence of CFG edge insertions and deletions and perform a batch update on the tree.

void	applyUpdates (ArrayRef< UpdateType > Updates, ArrayRef< UpdateType > PostViewUpdates)

void	insertEdge (BasicBlock From, BasicBlock To)
	Inform the dominator tree about a CFG edge insertion and update the tree.

void	deleteEdge (BasicBlock From, BasicBlock To)
	Inform the dominator tree about a CFG edge deletion and update the tree.

DomTreeNodeBase< BasicBlock > *	addNewBlock (BasicBlock BB, BasicBlock DomBB)
	Add a new node to the dominator tree information.

DomTreeNodeBase< BasicBlock > *	setNewRoot (BasicBlock *BB)
	Add a new node to the forward dominator tree and make it a new root.

void	changeImmediateDominator (DomTreeNodeBase< BasicBlock > N, DomTreeNodeBase< BasicBlock > NewIDom)
	changeImmediateDominator - This method is used to update the dominator tree information when a node's immediate dominator changes.

void	changeImmediateDominator (BasicBlock BB, BasicBlock NewBB)

void	eraseNode (BasicBlock *BB)
	eraseNode - Removes a node from the dominator tree.

void	splitBlock (BasicBlock *NewBB)
	splitBlock - BB is split and now it has one successor.

void	print (raw_ostream &O) const
	print - Convert to human readable form

void	updateDFSNumbers () const
	updateDFSNumbers - Assign In and Out numbers to the nodes while walking dominator tree in dfs order.

void	recalculate (ParentType &Func)
	recalculate - compute a dominator tree for the given function

void	recalculate (ParentType &Func, ArrayRef< UpdateType > Updates)

bool	verify (VerificationLevel VL=VerificationLevel::Full) const
	verify - checks if the tree is correct.

void	reset ()

Additional Inherited Members
Static Public Attributes inherited from llvm::DominatorTreeBase< BasicBlock, false >
static constexpr bool	IsPostDominator

static constexpr UpdateKind	Insert

static constexpr UpdateKind	Delete

Protected Types inherited from llvm::DominatorTreeBase< BasicBlock, false >
using	DomTreeNodeMapType = DenseMap< BasicBlock *, std::unique_ptr< DomTreeNodeBase< BasicBlock > > >

Protected Member Functions inherited from llvm::DominatorTreeBase< BasicBlock, false >
void	addRoot (BasicBlock *BB)

void	addRoot (MachineBasicBlock *MBB)

DomTreeNodeBase< BasicBlock > *	createChild (BasicBlock BB, DomTreeNodeBase< BasicBlock > IDom)

DomTreeNodeBase< BasicBlock > *	createNode (BasicBlock *BB)

void	Split (typename GraphTraits< N >::NodeRef NewBB)

Protected Attributes inherited from llvm::DominatorTreeBase< BasicBlock, false >
SmallVector< BasicBlock *, IsPostDom ? 4 :1 >	Roots

DomTreeNodeMapType	DomTreeNodes

DomTreeNodeBase< BasicBlock > *	RootNode

ParentPtr	Parent

bool	DFSInfoValid

unsigned int	SlowQueries

Detailed Description

Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree.

Definition: A block is said to be forward statically reachable if there is a path from the entry of the function to the block. A statically reachable block may become statically unreachable during optimization.

A forward unreachable block may appear in the dominator tree, or it may not. If it does, dominance queries will return results as if all reachable blocks dominate it. When asking for a Node corresponding to a potentially unreachable block, calling code must handle the case where the block was unreachable and the result of getNode() is nullptr.

Generally, a block known to be unreachable when the dominator tree is constructed will not be in the tree. One which becomes unreachable after the dominator tree is initially constructed may still exist in the tree, even if the tree is properly updated. Calling code should not rely on the preceding statements; this is stated only to assist human understanding.

Definition at line 166 of file Dominators.h.

Member Typedef Documentation

◆ Base

using llvm::DominatorTree::Base = DominatorTreeBase<BasicBlock, false>

Definition at line 168 of file Dominators.h.

Constructor & Destructor Documentation

◆ DominatorTree() [1/3]

llvm::DominatorTree::DominatorTree ( )

default

◆ DominatorTree() [2/3]

llvm::DominatorTree::DominatorTree ( Function & F )

inlineexplicit

Definition at line 171 of file Dominators.h.

References F.

◆ DominatorTree() [3/3]

llvm::DominatorTree::DominatorTree	(	DominatorTree &	DT,
		DomTreeBuilder::BBUpdates	U
	)

inlineexplicit

Definition at line 172 of file Dominators.h.

References llvm::DominatorTreeBase< NodeT, IsPostDom >::Parent.

Member Function Documentation

◆ dominates() [1/7]

bool DominatorTree::dominates	(	const BasicBlock *	BB,
		const Use &	U
	)		const

Return true if the (end of the) basic block BB dominates the use U.

Definition at line 122 of file Dominators.cpp.

References dominates(), llvm::Instruction::getParent(), and llvm::DominatorTreeBase< BasicBlock, false >::properlyDominates().

◆ dominates() [2/7]

bool DominatorTree::dominates	(	const BasicBlockEdge &	BBE,
		const BasicBlock *	BB
	)		const

Definition at line 200 of file Dominators.cpp.

References dominates(), llvm::BasicBlockEdge::getEnd(), llvm::BasicBlockEdge::getStart(), and llvm::predecessors().

◆ dominates() [3/7]

bool DominatorTree::dominates	(	const BasicBlockEdge &	BBE,
		const Use &	U
	)		const

Return true if an edge dominates a use.

If BBE is not a unique edge between start and end of the edge, it can never dominate the use.

Definition at line 250 of file Dominators.cpp.

References dominates(), llvm::BasicBlockEdge::getEnd(), llvm::PHINode::getIncomingBlock(), llvm::Instruction::getParent(), and llvm::BasicBlockEdge::getStart().

◆ dominates() [4/7]

bool DominatorTree::dominates	(	const BasicBlockEdge &	BBE1,
		const BasicBlockEdge &	BBE2
	)		const

Returns true if edge BBE1 dominates edge BBE2.

Definition at line 337 of file Dominators.cpp.

References dominates(), llvm::BasicBlockEdge::getEnd(), and llvm::BasicBlockEdge::getStart().

◆ dominates() [5/7]

bool DominatorTree::dominates	(	const Instruction *	Def,
		const BasicBlock *	BB
	)		const

Returns true if Def would dominate a use in any instruction in BB.

If Def is an instruction in BB, then Def does not dominate BB.

Does not accept Value to avoid ambiguity with dominance checks between two basic blocks.

Definition at line 174 of file Dominators.cpp.

References dominates(), E, and isReachableFromEntry().

◆ dominates() [6/7]

bool DominatorTree::dominates	(	const Value *	Def,
		const Instruction *	User
	)		const

Return true if value Def dominates all possible uses inside instruction User.

Same comments as for the Use-based API apply.

Definition at line 135 of file Dominators.cpp.

References assert(), dominates(), and isReachableFromEntry().

◆ dominates() [7/7]

bool DominatorTree::dominates	(	const Value *	Def,
		const Use &	U
	)		const

Return true if value Def dominates use U, in the sense that Def is available at U, and could be substituted as the used value without violating the SSA dominance requirement.

In particular, it is worth noting that:

Non-instruction Defs dominate everything.
Def does not dominate a use in Def itself (outside of degenerate cases like unreachable code or trivial phi cycles).
Invoke Defs only dominate uses in their default destination.

Definition at line 268 of file Dominators.cpp.

References assert(), dominates(), E, llvm::Instruction::getParent(), and isReachableFromEntry().