Delete unnecessary elses.
[oota-llvm.git] / include / llvm / CodeGen / MachineBasicBlock.h
index fb037402903d249b8b436783dfc9f5187328a41f..54ac47008f231acd9a07ea296a6a1ddc11a24b27 100644 (file)
@@ -1,12 +1,12 @@
 //===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-// 
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
 //===----------------------------------------------------------------------===//
-// 
+//
 // Collect the sequence of machine instructions for a basic block.
 //
 //===----------------------------------------------------------------------===//
 #define LLVM_CODEGEN_MACHINEBASICBLOCK_H
 
 #include "llvm/CodeGen/MachineInstr.h"
-#include "Support/GraphTraits.h"
-#include "Support/ilist"
-#include <iosfwd>
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/Support/Streams.h"
 
 namespace llvm {
-  class MachineFunction;
 
-// ilist_traits
+class BasicBlock;
+class MachineFunction;
+
 template <>
-class ilist_traits<MachineInstr> {
-  // this is only set by the MachineBasicBlock owning the ilist
+struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
+private:
+  mutable MachineInstr Sentinel;
+
+  // this is only set by the MachineBasicBlock owning the LiveList
   friend class MachineBasicBlock;
-  MachineBasicBlock* parent;
+  MachineBasicBlock* Parent;
 
 public:
-  ilist_traits<MachineInstr>() : parent(0) { }
-
-  static MachineInstr* getPrev(MachineInstr* N) { return N->prev; }
-  static MachineInstr* getNext(MachineInstr* N) { return N->next; }
-
-  static const MachineInstr*
-  getPrev(const MachineInstr* N) { return N->prev; }
+  MachineInstr *createSentinel() const { return &Sentinel; }
+  void destroySentinel(MachineInstr *) const {}
 
-  static const MachineInstr*
-  getNext(const MachineInstr* N) { return N->next; }
-
-  static void setPrev(MachineInstr* N, MachineInstr* prev) { N->prev = prev; }
-  static void setNext(MachineInstr* N, MachineInstr* next) { N->next = next; }
-
-  static MachineInstr* createNode();
   void addNodeToList(MachineInstr* N);
   void removeNodeFromList(MachineInstr* N);
-  void transferNodesFromList(
-      iplist<MachineInstr, ilist_traits<MachineInstr> >& toList,
-      ilist_iterator<MachineInstr> first,
-      ilist_iterator<MachineInstr> last);
+  void transferNodesFromList(ilist_traits &SrcTraits,
+                             ilist_iterator<MachineInstr> first,
+                             ilist_iterator<MachineInstr> last);
+  void deleteNode(MachineInstr *N);
+private:
+  void createNode(const MachineInstr &);
 };
 
-class BasicBlock;
-
-class MachineBasicBlock {
-public:
+class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
   typedef ilist<MachineInstr> Instructions;
   Instructions Insts;
-  MachineBasicBlock *Prev, *Next;
   const BasicBlock *BB;
+  int Number;
+  MachineFunction *xParent;
+  
+  /// Predecessors/Successors - Keep track of the predecessor / successor
+  /// basicblocks.
   std::vector<MachineBasicBlock *> Predecessors;
   std::vector<MachineBasicBlock *> Successors;
-  int Number;
-  MachineFunction *Parent;
 
-public:
-  MachineBasicBlock(const BasicBlock *bb = 0) : Prev(0), Next(0), BB(bb),
-                                                Number(-1), Parent(0) {
-    Insts.parent = this;
-  }
+  /// LiveIns - Keep track of the physical registers that are livein of
+  /// the basicblock.
+  std::vector<unsigned> LiveIns;
 
-  ~MachineBasicBlock();
+  /// Alignment - Alignment of the basic block. Zero if the basic block does
+  /// not need to be aligned.
+  unsigned Alignment;
   
+  /// IsLandingPad - Indicate that this basic block is entered via an
+  /// exception handler.
+  bool IsLandingPad;
+
+  // Intrusive list support
+  friend struct ilist_sentinel_traits<MachineBasicBlock>;
+  MachineBasicBlock() {}
+
+  explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
+
+  ~MachineBasicBlock();
+
+  // MachineBasicBlocks are allocated and owned by MachineFunction.
+  friend class MachineFunction;
+
+public:
   /// getBasicBlock - Return the LLVM basic block that this instance
   /// corresponded to originally.
   ///
@@ -81,19 +89,21 @@ public:
 
   /// getParent - Return the MachineFunction containing this basic block.
   ///
-  const MachineFunction *getParent() const { return Parent; }
-  MachineFunction *getParent() { return Parent; }
+  const MachineFunction *getParent() const { return xParent; }
+  MachineFunction *getParent() { return xParent; }
 
-  typedef ilist<MachineInstr>::iterator                       iterator;
-  typedef ilist<MachineInstr>::const_iterator           const_iterator;
+  typedef Instructions::iterator                              iterator;
+  typedef Instructions::const_iterator                  const_iterator;
   typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
   typedef std::reverse_iterator<iterator>             reverse_iterator;
 
-  unsigned size() const { return Insts.size(); }
+  unsigned size() const { return (unsigned)Insts.size(); }
   bool empty() const { return Insts.empty(); }
 
   MachineInstr& front() { return Insts.front(); }
   MachineInstr& back()  { return Insts.back(); }
+  const MachineInstr& front() const { return Insts.front(); }
+  const MachineInstr& back()  const { return Insts.back(); }
 
   iterator                begin()       { return Insts.begin();  }
   const_iterator          begin() const { return Insts.begin();  }
@@ -109,49 +119,129 @@ public:
   typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
   typedef std::vector<MachineBasicBlock *>::iterator       succ_iterator;
   typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
-  
-  pred_iterator        pred_begin()       { return Predecessors.begin (); }
-  const_pred_iterator  pred_begin() const { return Predecessors.begin (); }
-  pred_iterator        pred_end()         { return Predecessors.end ();   }
-  const_pred_iterator  pred_end()   const { return Predecessors.end ();   }
-  unsigned             pred_size()  const { return Predecessors.size ();  }
-  bool                 pred_empty() const { return Predecessors.empty();  }
-  succ_iterator        succ_begin()       { return Successors.begin ();   }
-  const_succ_iterator  succ_begin() const { return Successors.begin ();   }
-  succ_iterator        succ_end()         { return Successors.end ();     }
-  const_succ_iterator  succ_end()   const { return Successors.end ();     }
-  unsigned             succ_size()  const { return Successors.size ();    }
-  bool                 succ_empty() const { return Successors.empty();    }
+  typedef std::vector<MachineBasicBlock *>::reverse_iterator
+                                                         pred_reverse_iterator;
+  typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
+                                                   const_pred_reverse_iterator;
+  typedef std::vector<MachineBasicBlock *>::reverse_iterator
+                                                         succ_reverse_iterator;
+  typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
+                                                   const_succ_reverse_iterator;
+
+  pred_iterator        pred_begin()       { return Predecessors.begin(); }
+  const_pred_iterator  pred_begin() const { return Predecessors.begin(); }
+  pred_iterator        pred_end()         { return Predecessors.end();   }
+  const_pred_iterator  pred_end()   const { return Predecessors.end();   }
+  pred_reverse_iterator        pred_rbegin()
+                                          { return Predecessors.rbegin();}
+  const_pred_reverse_iterator  pred_rbegin() const
+                                          { return Predecessors.rbegin();}
+  pred_reverse_iterator        pred_rend()
+                                          { return Predecessors.rend();  }
+  const_pred_reverse_iterator  pred_rend()   const
+                                          { return Predecessors.rend();  }
+  unsigned             pred_size()  const {
+    return (unsigned)Predecessors.size();
+  }
+  bool                 pred_empty() const { return Predecessors.empty(); }
+  succ_iterator        succ_begin()       { return Successors.begin();   }
+  const_succ_iterator  succ_begin() const { return Successors.begin();   }
+  succ_iterator        succ_end()         { return Successors.end();     }
+  const_succ_iterator  succ_end()   const { return Successors.end();     }
+  succ_reverse_iterator        succ_rbegin()
+                                          { return Successors.rbegin();  }
+  const_succ_reverse_iterator  succ_rbegin() const
+                                          { return Successors.rbegin();  }
+  succ_reverse_iterator        succ_rend()
+                                          { return Successors.rend();    }
+  const_succ_reverse_iterator  succ_rend()   const
+                                          { return Successors.rend();    }
+  unsigned             succ_size()  const {
+    return (unsigned)Successors.size();
+  }
+  bool                 succ_empty() const { return Successors.empty();   }
 
-  // Machine-CFG mutators
+  // LiveIn management methods.
 
+  /// addLiveIn - Add the specified register as a live in.  Note that it
+  /// is an error to add the same register to the same set more than once.
+  void addLiveIn(unsigned Reg)  { LiveIns.push_back(Reg); }
+
+  /// removeLiveIn - Remove the specified register from the live in set.
+  ///
+  void removeLiveIn(unsigned Reg);
+
+  /// isLiveIn - Return true if the specified register is in the live in set.
+  ///
+  bool isLiveIn(unsigned Reg) const;
+
+  // Iteration support for live in sets.  These sets are kept in sorted
+  // order by their register number.
+  typedef std::vector<unsigned>::iterator       livein_iterator;
+  typedef std::vector<unsigned>::const_iterator const_livein_iterator;
+  livein_iterator       livein_begin()       { return LiveIns.begin(); }
+  const_livein_iterator livein_begin() const { return LiveIns.begin(); }
+  livein_iterator       livein_end()         { return LiveIns.end(); }
+  const_livein_iterator livein_end()   const { return LiveIns.end(); }
+  bool            livein_empty() const { return LiveIns.empty(); }
+
+  /// getAlignment - Return alignment of the basic block.
+  ///
+  unsigned getAlignment() const { return Alignment; }
+
+  /// setAlignment - Set alignment of the basic block.
+  ///
+  void setAlignment(unsigned Align) { Alignment = Align; }
+
+  /// isLandingPad - Returns true if the block is a landing pad. That is
+  /// this basic block is entered via an exception handler.
+  bool isLandingPad() const { return IsLandingPad; }
+
+  /// setIsLandingPad - Indicates the block is a landing pad.  That is
+  /// this basic block is entered via an exception handler.
+  void setIsLandingPad() { IsLandingPad = true; }
+
+  // Code Layout methods.
+  
+  /// moveBefore/moveAfter - move 'this' block before or after the specified
+  /// block.  This only moves the block, it does not modify the CFG or adjust
+  /// potential fall-throughs at the end of the block.
+  void moveBefore(MachineBasicBlock *NewAfter);
+  void moveAfter(MachineBasicBlock *NewBefore);
+  
+  // Machine-CFG mutators
+  
   /// addSuccessor - Add succ as a successor of this MachineBasicBlock.
   /// The Predecessors list of succ is automatically updated.
   ///
-  void addSuccessor(MachineBasicBlock *succ) {
-    Successors.push_back(succ);
-    succ->addPredecessor(this);
-  }
+  void addSuccessor(MachineBasicBlock *succ);
 
   /// removeSuccessor - Remove successor from the successors list of this
   /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
   ///
-  void removeSuccessor(MachineBasicBlock *succ) {
-    succ->removePredecessor(this);
-    succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
-    assert(I != Successors.end() && "Not a current successor!");
-    Successors.erase(I);
-  }
+  void removeSuccessor(MachineBasicBlock *succ);
 
   /// removeSuccessor - Remove specified successor from the successors list of
   /// this MachineBasicBlock. The Predecessors list of succ is automatically
-  /// updated.
+  /// updated.  Return the iterator to the element after the one removed.
   ///
-  void removeSuccessor(succ_iterator I) {
-    assert(I != Successors.end() && "Not a current successor!");
-    (*I)->removePredecessor(this);
-    Successors.erase(I);
-  }
+  succ_iterator removeSuccessor(succ_iterator I);
+  
+  /// transferSuccessors - Transfers all the successors from MBB to this
+  /// machine basic block (i.e., copies all the successors fromMBB and
+  /// remove all the successors fromBB).
+  void transferSuccessors(MachineBasicBlock *fromMBB);
+  
+  /// isSuccessor - Return true if the specified MBB is a successor of this
+  /// block.
+  bool isSuccessor(MachineBasicBlock *MBB) const;
+
+  /// isLayoutSuccessor - Return true if the specified MBB will be emitted
+  /// immediately after this block, such that if this block exits by
+  /// falling through, control will transfer to the specified MBB. Note
+  /// that MBB need not be a successor at all, for example if this block
+  /// ends with an unconditional branch to some other block.
+  bool isLayoutSuccessor(MachineBasicBlock *MBB) const;
 
   /// getFirstTerminator - returns an iterator to the first terminator
   /// instruction of this basic block. If a terminator does not exist,
@@ -172,7 +262,13 @@ public:
   iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
   MachineInstr *remove(MachineInstr *I)  { return Insts.remove(I); }
   void clear()                           { Insts.clear(); }
-  
+
+  /// splice - Take an instruction from MBB 'Other' at the position From,
+  /// and insert it into this MBB right before 'where'.
+  void splice(iterator where, MachineBasicBlock *Other, iterator From) {
+    Insts.splice(where, Other->Insts, From);
+  }
+
   /// splice - Take a block of instructions from MBB 'Other' in the range [From,
   /// To), and insert them into this MBB right before 'where'.
   void splice(iterator where, MachineBasicBlock *Other, iterator From,
@@ -180,23 +276,42 @@ public:
     Insts.splice(where, Other->Insts, From, To);
   }
 
+  /// removeFromParent - This method unlinks 'this' from the containing
+  /// function, and returns it, but does not delete it.
+  MachineBasicBlock *removeFromParent();
+  
+  /// eraseFromParent - This method unlinks 'this' from the containing
+  /// function and deletes it.
+  void eraseFromParent();
+
+  /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
+  /// 'Old', change the code and CFG so that it branches to 'New' instead.
+  void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
+
+  /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
+  /// the CFG to be inserted.  If we have proven that MBB can only branch to
+  /// DestA and DestB, remove any other MBB successors from the CFG. DestA and
+  /// DestB can be null. Besides DestA and DestB, retain other edges leading
+  /// to LandingPads (currently there can be only one; we don't check or require
+  /// that here). Note it is possible that DestA and/or DestB are LandingPads.
+  bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
+                            MachineBasicBlock *DestB,
+                            bool isCond);
+
   // Debugging methods.
   void dump() const;
   void print(std::ostream &OS) const;
+  void print(std::ostream *OS) const { if (OS) print(*OS); }
 
   /// getNumber - MachineBasicBlocks are uniquely numbered at the function
   /// level, unless they're not in a MachineFunction yet, in which case this
   /// will return -1.
   ///
   int getNumber() const { return Number; }
+  void setNumber(int N) { Number = N; }
 
 private:   // Methods used to maintain doubly linked list of blocks...
-  friend class ilist_traits<MachineBasicBlock>;
-
-  MachineBasicBlock *getPrev() const { return Prev; }
-  MachineBasicBlock *getNext() const { return Next; }
-  void setPrev(MachineBasicBlock *P) { Prev = P; }
-  void setNext(MachineBasicBlock *N) { Next = N; }
+  friend struct ilist_traits<MachineBasicBlock>;
 
   // Machine-CFG mutators
 
@@ -204,32 +319,17 @@ private:   // Methods used to maintain doubly linked list of blocks...
   /// Don't do this unless you know what you're doing, because it doesn't
   /// update pred's successors list. Use pred->addSuccessor instead.
   ///
-  void addPredecessor (MachineBasicBlock *pred) {
-    Predecessors.push_back (pred);
-  }
+  void addPredecessor(MachineBasicBlock *pred);
 
   /// removePredecessor - Remove pred as a predecessor of this
   /// MachineBasicBlock. Don't do this unless you know what you're
   /// doing, because it doesn't update pred's successors list. Use
   /// pred->removeSuccessor instead.
   ///
-  void removePredecessor (MachineBasicBlock *pred) {
-    std::vector<MachineBasicBlock *>::iterator goner =
-      std::find (Predecessors.begin(), Predecessors.end (), pred);
-    Predecessors.erase (goner);
-  }
-};
-
-// This is useful when building DenseMaps keyed on MachineBasicBlocks
-struct MachineBasicBlock2IndexFunctor
-  : std::unary_function<const MachineBasicBlock*, unsigned> {
-  unsigned operator()(const MachineBasicBlock* MBB) const {
-    assert(MBB->getNumber() != -1 &&
-           "MachineBasicBlock does not belong to a MachineFunction");
-    return MBB->getNumber();
-  }
+  void removePredecessor(MachineBasicBlock *pred);
 };
 
+std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
 
 //===--------------------------------------------------------------------===//
 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
@@ -244,10 +344,10 @@ template <> struct GraphTraits<MachineBasicBlock *> {
   typedef MachineBasicBlock::succ_iterator ChildIteratorType;
 
   static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
-  static inline ChildIteratorType child_begin(NodeType *N) { 
+  static inline ChildIteratorType child_begin(NodeType *N) {
     return N->succ_begin();
   }
-  static inline ChildIteratorType child_end(NodeType *N) { 
+  static inline ChildIteratorType child_end(NodeType *N) {
     return N->succ_end();
   }
 };
@@ -257,10 +357,10 @@ template <> struct GraphTraits<const MachineBasicBlock *> {
   typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
 
   static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
-  static inline ChildIteratorType child_begin(NodeType *N) { 
+  static inline ChildIteratorType child_begin(NodeType *N) {
     return N->succ_begin();
   }
-  static inline ChildIteratorType child_end(NodeType *N) { 
+  static inline ChildIteratorType child_end(NodeType *N) {
     return N->succ_end();
   }
 };
@@ -277,10 +377,10 @@ template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
   static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
     return G.Graph;
   }
-  static inline ChildIteratorType child_begin(NodeType *N) { 
+  static inline ChildIteratorType child_begin(NodeType *N) {
     return N->pred_begin();
   }
-  static inline ChildIteratorType child_end(NodeType *N) { 
+  static inline ChildIteratorType child_end(NodeType *N) {
     return N->pred_end();
   }
 };
@@ -289,12 +389,12 @@ template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
   typedef const MachineBasicBlock NodeType;
   typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
   static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
-    return G.Graph; 
+    return G.Graph;
   }
-  static inline ChildIteratorType child_begin(NodeType *N) { 
+  static inline ChildIteratorType child_begin(NodeType *N) {
     return N->pred_begin();
   }
-  static inline ChildIteratorType child_end(NodeType *N) { 
+  static inline ChildIteratorType child_end(NodeType *N) {
     return N->pred_end();
   }
 };