//===----------------------------------------------------------------------===//
//
// This file defines the following classes:
-// 1. DominatorSet: Calculates the [reverse] dominator set for a function
-// 2. ImmediateDominators: Calculates and holds a mapping between BasicBlocks
+// 1. ImmediateDominators: Calculates and holds a mapping between BasicBlocks
// and their immediate dominator.
+// 2. DominatorSet: Calculates the [reverse] dominator set for a function
// 3. DominatorTree: Represent the ImmediateDominator as an explicit tree
// structure.
// 4. DominanceFrontier: Calculate and hold the dominance frontier for a
#include "llvm/Pass.h"
#include <set>
+namespace llvm {
+
class Instruction;
template <typename GraphType> struct GraphTraits;
//===----------------------------------------------------------------------===//
-//
-// DominatorBase - Base class that other, more interesting dominator analyses
-// inherit from.
-//
+/// DominatorBase - Base class that other, more interesting dominator analyses
+/// inherit from.
+///
class DominatorBase : public FunctionPass {
protected:
std::vector<BasicBlock*> Roots;
inline DominatorBase(bool isPostDom) : Roots(), IsPostDominators(isPostDom) {}
public:
- // 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).
+ /// 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).
+ ///
inline const std::vector<BasicBlock*> &getRoots() const { return Roots; }
- // Returns true if analysis based of postdoms
+ /// isPostDominator - Returns true if analysis based of postdoms
+ ///
bool isPostDominator() const { return IsPostDominators; }
};
+
//===----------------------------------------------------------------------===//
-//
-// DominatorSet - Maintain a set<BasicBlock*> for every basic block in a
-// function, that represents the blocks that dominate the block. If the block
-// is unreachable in this function, the set will be empty. This cannot happen
-// for reachable code, because every block dominates at least itself.
-//
+/// ImmediateDominators - Calculate the immediate dominator for each node in a
+/// function.
+///
+class ImmediateDominatorsBase : public DominatorBase {
+protected:
+ std::map<BasicBlock*, BasicBlock*> IDoms;
+public:
+ ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
+
+ virtual void releaseMemory() { IDoms.clear(); }
+
+ // Accessor interface:
+ typedef std::map<BasicBlock*, BasicBlock*> IDomMapType;
+ typedef IDomMapType::const_iterator const_iterator;
+ inline const_iterator begin() const { return IDoms.begin(); }
+ inline const_iterator end() const { return IDoms.end(); }
+ inline const_iterator find(BasicBlock* B) const { return IDoms.find(B);}
+
+ /// operator[] - Return the idom for the specified basic block. The start
+ /// node returns null, because it does not have an immediate dominator.
+ ///
+ inline BasicBlock *operator[](BasicBlock *BB) const {
+ return get(BB);
+ }
+
+ /// get() - Synonym for operator[].
+ ///
+ inline BasicBlock *get(BasicBlock *BB) const {
+ std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
+ return I != IDoms.end() ? I->second : 0;
+ }
+
+ //===--------------------------------------------------------------------===//
+ // API to update Immediate(Post)Dominators information based on modifications
+ // to the CFG...
+
+ /// addNewBlock - Add a new block to the CFG, with the specified immediate
+ /// dominator.
+ ///
+ void addNewBlock(BasicBlock *BB, BasicBlock *IDom) {
+ assert(get(BB) == 0 && "BasicBlock already in idom info!");
+ IDoms[BB] = IDom;
+ }
+
+ /// setImmediateDominator - Update the immediate dominator information to
+ /// change the current immediate dominator for the specified block to another
+ /// block. This method requires that BB already have an IDom, otherwise just
+ /// use addNewBlock.
+ ///
+ void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom) {
+ assert(IDoms.find(BB) != IDoms.end() && "BB doesn't have idom yet!");
+ IDoms[BB] = NewIDom;
+ }
+
+ /// print - Convert to human readable form
+ ///
+ virtual void print(std::ostream &OS, const Module* = 0) const;
+};
+
+//===-------------------------------------
+/// ImmediateDominators Class - Concrete subclass of ImmediateDominatorsBase
+/// that is used to compute a normal immediate dominator set.
+///
+struct ImmediateDominators : public ImmediateDominatorsBase {
+ ImmediateDominators() : ImmediateDominatorsBase(false) {}
+
+ BasicBlock *getRoot() const {
+ assert(Roots.size() == 1 && "Should always have entry node!");
+ return Roots[0];
+ }
+
+ virtual bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ }
+
+private:
+ struct InfoRec {
+ unsigned Semi;
+ unsigned Size;
+ BasicBlock *Label, *Parent, *Child, *Ancestor;
+
+ std::vector<BasicBlock*> Bucket;
+
+ InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0){}
+ };
+
+ // Vertex - Map the DFS number to the BasicBlock*
+ std::vector<BasicBlock*> Vertex;
+
+ // Info - Collection of information used during the computation of idoms.
+ std::map<BasicBlock*, InfoRec> Info;
+
+ unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
+ void Compress(BasicBlock *V, InfoRec &VInfo);
+ BasicBlock *Eval(BasicBlock *v);
+ void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
+};
+
+
+
+//===----------------------------------------------------------------------===//
+/// DominatorSet - Maintain a set<BasicBlock*> for every basic block in a
+/// function, that represents the blocks that dominate the block. If the block
+/// is unreachable in this function, the set will be empty. This cannot happen
+/// for reachable code, because every block dominates at least itself.
+///
struct DominatorSetBase : public DominatorBase {
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
// Map of dom sets
/// isReachable - Return true if the specified basicblock is reachable. If
/// the block is reachable, we have dominator set information for it.
+ ///
bool isReachable(BasicBlock *BB) const {
return !getDominators(BB).empty();
}
}
/// print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ ///
+ virtual void print(std::ostream &OS, const Module* = 0) const;
/// dominates - Return true if A dominates B. This performs the special
/// checks necessary if A and B are in the same basic block.
/// addBasicBlock - Call to update the dominator set with information about a
/// new block that was inserted into the function.
+ ///
void addBasicBlock(BasicBlock *BB, const DomSetType &Dominators) {
assert(find(BB) == end() && "Block already in DominatorSet!");
Doms.insert(std::make_pair(BB, Dominators));
}
- // addDominator - If a new block is inserted into the CFG, then method may be
- // called to notify the blocks it dominates that it is in their set.
- //
+ /// addDominator - If a new block is inserted into the CFG, then method may be
+ /// called to notify the blocks it dominates that it is in their set.
+ ///
void addDominator(BasicBlock *BB, BasicBlock *NewDominator) {
iterator I = find(BB);
assert(I != end() && "BB is not in DominatorSet!");
//===-------------------------------------
-// DominatorSet Class - Concrete subclass of DominatorSetBase that is used to
-// compute a normal dominator set.
-//
+/// DominatorSet Class - Concrete subclass of DominatorSetBase that is used to
+/// compute a normal dominator set.
+///
struct DominatorSet : public DominatorSetBase {
DominatorSet() : DominatorSetBase(false) {}
virtual bool runOnFunction(Function &F);
- /// recalculate - This method may be called by external passes that modify the
- /// CFG and then need dominator information recalculated. This method is
- /// obviously really slow, so it should be avoided if at all possible.
- void recalculate();
-
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
return Roots[0];
}
- // getAnalysisUsage - This simply provides a dominator set
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- }
-private:
- void calculateDominatorsFromBlock(BasicBlock *BB);
-};
-
-
-//===----------------------------------------------------------------------===//
-//
-// ImmediateDominators - Calculate the immediate dominator for each node in a
-// function.
-//
-class ImmediateDominatorsBase : public DominatorBase {
-protected:
- std::map<BasicBlock*, BasicBlock*> IDoms;
- void calcIDoms(const DominatorSetBase &DS);
-public:
- ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
-
- virtual void releaseMemory() { IDoms.clear(); }
-
- // Accessor interface:
- typedef std::map<BasicBlock*, BasicBlock*> IDomMapType;
- typedef IDomMapType::const_iterator const_iterator;
- inline const_iterator begin() const { return IDoms.begin(); }
- inline const_iterator end() const { return IDoms.end(); }
- inline const_iterator find(BasicBlock* B) const { return IDoms.find(B);}
-
- // operator[] - Return the idom for the specified basic block. The start
- // node returns null, because it does not have an immediate dominator.
- //
- inline BasicBlock *operator[](BasicBlock *BB) const {
- return get(BB);
- }
-
- // get() - Synonym for operator[].
- inline BasicBlock *get(BasicBlock *BB) const {
- std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
- }
-
- //===--------------------------------------------------------------------===//
- // API to update Immediate(Post)Dominators information based on modifications
- // to the CFG...
-
- /// addNewBlock - Add a new block to the CFG, with the specified immediate
- /// dominator.
+ /// getAnalysisUsage - This simply provides a dominator set
///
- void addNewBlock(BasicBlock *BB, BasicBlock *IDom) {
- assert(get(BB) == 0 && "BasicBlock already in idom info!");
- IDoms[BB] = IDom;
- }
-
- /// setImmediateDominator - Update the immediate dominator information to
- /// change the current immediate dominator for the specified block to another
- /// block. This method requires that BB already have an IDom, otherwise just
- /// use addNewBlock.
- void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom) {
- assert(IDoms.find(BB) != IDoms.end() && "BB doesn't have idom yet!");
- IDoms[BB] = NewIDom;
- }
-
- // print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
-};
-
-//===-------------------------------------
-// ImmediateDominators Class - Concrete subclass of ImmediateDominatorsBase that
-// is used to compute a normal immediate dominator set.
-//
-struct ImmediateDominators : public ImmediateDominatorsBase {
- ImmediateDominators() : ImmediateDominatorsBase(false) {}
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
- }
-
- virtual bool runOnFunction(Function &F) {
- IDoms.clear(); // Reset from the last time we were run...
- DominatorSet &DS = getAnalysis<DominatorSet>();
- Roots = DS.getRoots();
- calcIDoms(DS);
- return false;
- }
-
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<ImmediateDominators>();
AU.setPreservesAll();
- AU.addRequired<DominatorSet>();
}
+
+ // stub - dummy function, just ignore it
+ static void stub();
};
//===----------------------------------------------------------------------===//
-//
-// DominatorTree - Calculate the immediate dominator tree for a function.
-//
+/// DominatorTree - Calculate the immediate dominator tree for a function.
+///
struct DominatorTreeBase : public DominatorBase {
class Node;
protected:
Node *RootNode;
public:
class Node {
- friend class DominatorTree;
- friend class PostDominatorTree;
- friend class DominatorTreeBase;
+ friend struct DominatorTree;
+ friend struct PostDominatorTree;
+ friend struct DominatorTreeBase;
BasicBlock *TheBB;
Node *IDom;
std::vector<Node*> Children;
inline Node *getIDom() const { return IDom; }
inline const std::vector<Node*> &getChildren() const { return Children; }
- // dominates - Returns true iff this dominates N. Note that this is not a
- // constant time operation!
+ /// dominates - Returns true iff this dominates N. Note that this is not a
+ /// constant time operation!
+ ///
inline bool dominates(const Node *N) const {
const Node *IDom;
while ((IDom = N->getIDom()) != 0 && IDom != this)
- N = IDom; // Walk up the tree
+ N = IDom; // Walk up the tree
return IDom != 0;
}
private:
- inline Node(BasicBlock *BB, Node *iDom)
- : TheBB(BB), IDom(iDom) {}
+ inline Node(BasicBlock *BB, Node *iDom) : TheBB(BB), IDom(iDom) {}
inline Node *addChild(Node *C) { Children.push_back(C); return C; }
void setIDom(Node *NewIDom);
return getNode(BB);
}
- // getRootNode - This returns the entry node for the CFG of the function. If
- // this tree represents the post-dominance relations for a function, however,
- // this root may be a node with the block == NULL. This is the case when
- // there are multiple exit nodes from a particular function. Consumers of
- // post-dominance information must be capable of dealing with this
- // possibility.
- //
+ /// getRootNode - This returns the entry node for the CFG of the function. If
+ /// this tree represents the post-dominance relations for a function, however,
+ /// this root may be a node with the block == NULL. This is the case when
+ /// there are multiple exit nodes from a particular function. Consumers of
+ /// post-dominance information must be capable of dealing with this
+ /// possibility.
+ ///
Node *getRootNode() { return RootNode; }
const Node *getRootNode() const { return RootNode; }
/// changeImmediateDominator - This method is used to update the dominator
/// tree information when a node's immediate dominator changes.
///
- void changeImmediateDominator(Node *Node, Node *NewIDom) {
- assert(Node && NewIDom && "Cannot change null node pointers!");
- Node->setIDom(NewIDom);
+ void changeImmediateDominator(Node *N, Node *NewIDom) {
+ assert(N && NewIDom && "Cannot change null node pointers!");
+ N->setIDom(NewIDom);
}
/// print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ ///
+ virtual void print(std::ostream &OS, const Module* = 0) const;
};
//===-------------------------------------
-// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-// compute a normal dominator tree.
-//
+/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+/// compute a normal dominator tree.
+///
struct DominatorTree : public DominatorTreeBase {
DominatorTree() : DominatorTreeBase(false) {}
virtual bool runOnFunction(Function &F) {
reset(); // Reset from the last time we were run...
- DominatorSet &DS = getAnalysis<DominatorSet>();
- Roots = DS.getRoots();
- calculate(DS);
+ ImmediateDominators &ID = getAnalysis<ImmediateDominators>();
+ Roots = ID.getRoots();
+ calculate(ID);
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
- AU.addRequired<DominatorSet>();
+ AU.addRequired<ImmediateDominators>();
}
private:
- void calculate(const DominatorSet &DS);
+ void calculate(const ImmediateDominators &ID);
+ Node *getNodeForBlock(BasicBlock *BB);
};
//===-------------------------------------
-// DominatorTree GraphTraits specialization so the DominatorTree can be
-// iterable by generic graph iterators.
-
+/// DominatorTree GraphTraits specialization so the DominatorTree can be
+/// iterable by generic graph iterators.
+///
template <> struct GraphTraits<DominatorTree::Node*> {
typedef DominatorTree::Node NodeType;
typedef NodeType::iterator ChildIteratorType;
};
//===----------------------------------------------------------------------===//
-//
-// DominanceFrontier - Calculate the dominance frontiers for a function.
-//
+/// DominanceFrontier - Calculate the dominance frontiers for a function.
+///
struct DominanceFrontierBase : public DominatorBase {
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
I->second.erase(Node);
}
- // print - Convert to human readable form
- virtual void print(std::ostream &OS) const;
+ /// print - Convert to human readable form
+ ///
+ virtual void print(std::ostream &OS, const Module* = 0) const;
};
//===-------------------------------------
-// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-// compute a normal dominator tree.
-//
+/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
+/// compute a normal dominator tree.
+///
struct DominanceFrontier : public DominanceFrontierBase {
DominanceFrontier() : DominanceFrontierBase(false) {}
const DominatorTree::Node *Node);
};
+// Make sure that any clients of this file link in Dominators.cpp
+static IncludeFile
+DOMINATORS_INCLUDE_FILE((void*)&DominatorSet::stub);
+} // End llvm namespace
+
#endif
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