Import LLVM, at r72732.

1 files changed, 235 insertions, 0 deletions

diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h
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+++ b/include/llvm/BasicBlock.h
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+//===-- llvm/BasicBlock.h - Represent a basic block in the VM ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the BasicBlock class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BASICBLOCK_H
+#define LLVM_BASICBLOCK_H
+
+#include "llvm/Instruction.h"
+#include "llvm/SymbolTableListTraits.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/Support/DataTypes.h"
+
+namespace llvm {
+
+class TerminatorInst;
+
+template<> struct ilist_traits<Instruction>
+  : public SymbolTableListTraits<Instruction, BasicBlock> {
+  // createSentinel is used to get hold of a node that marks the end of
+  // the list...
+  // The sentinel is relative to this instance, so we use a non-static
+  // method.
+  Instruction *createSentinel() const {
+    // since i(p)lists always publicly derive from the corresponding
+    // traits, placing a data member in this class will augment i(p)list.
+    // But since the NodeTy is expected to publicly derive from
+    // ilist_node<NodeTy>, there is a legal viable downcast from it
+    // to NodeTy. We use this trick to superpose i(p)list with a "ghostly"
+    // NodeTy, which becomes the sentinel. Dereferencing the sentinel is
+    // forbidden (save the ilist_node<NodeTy>) so no one will ever notice
+    // the superposition.
+    return static_cast<Instruction*>(&Sentinel);
+  }
+  static void destroySentinel(Instruction*) {}
+
+  Instruction *provideInitialHead() const { return createSentinel(); }
+  Instruction *ensureHead(Instruction*) const { return createSentinel(); }
+  static void noteHead(Instruction*, Instruction*) {}
+private:
+  mutable ilist_node<Instruction> Sentinel;
+};
+
+/// This represents a single basic block in LLVM. A basic block is simply a
+/// container of instructions that execute sequentially. Basic blocks are Values
+/// because they are referenced by instructions such as branches and switch
+/// tables. The type of a BasicBlock is "Type::LabelTy" because the basic block
+/// represents a label to which a branch can jump.
+///
+/// A well formed basic block is formed of a list of non-terminating 
+/// instructions followed by a single TerminatorInst instruction.  
+/// TerminatorInst's may not occur in the middle of basic blocks, and must 
+/// terminate the blocks. The BasicBlock class allows malformed basic blocks to
+/// occur because it may be useful in the intermediate stage of constructing or
+/// modifying a program. However, the verifier will ensure that basic blocks
+/// are "well formed".
+/// @brief LLVM Basic Block Representation
+class BasicBlock : public Value, // Basic blocks are data objects also
+                   public ilist_node<BasicBlock> {
+
+public:
+  typedef iplist<Instruction> InstListType;
+private:
+  InstListType InstList;
+  Function *Parent;
+
+  void setParent(Function *parent);
+  friend class SymbolTableListTraits<BasicBlock, Function>;
+
+  BasicBlock(const BasicBlock &);     // Do not implement
+  void operator=(const BasicBlock &); // Do not implement
+
+  /// BasicBlock ctor - If the function parameter is specified, the basic block
+  /// is automatically inserted at either the end of the function (if
+  /// InsertBefore is null), or before the specified basic block.
+  ///
+  explicit BasicBlock(const std::string &Name = "", Function *Parent = 0,
+                      BasicBlock *InsertBefore = 0);
+public:
+  /// Instruction iterators...
+  typedef InstListType::iterator                              iterator;
+  typedef InstListType::const_iterator                  const_iterator;
+
+  /// Create - Creates a new BasicBlock. If the Parent parameter is specified,
+  /// the basic block is automatically inserted at either the end of the
+  /// function (if InsertBefore is 0), or before the specified basic block.
+  static BasicBlock *Create(const std::string &Name = "", Function *Parent = 0,
+                            BasicBlock *InsertBefore = 0) {
+    return new BasicBlock(Name, Parent, InsertBefore);
+  }
+  ~BasicBlock();
+
+  /// getParent - Return the enclosing method, or null if none
+  ///
+  const Function *getParent() const { return Parent; }
+        Function *getParent()       { return Parent; }
+
+  /// use_back - Specialize the methods defined in Value, as we know that an
+  /// BasicBlock can only be used by Instructions (specifically PHI nodes and
+  /// terminators).
+  Instruction       *use_back()       { return cast<Instruction>(*use_begin());}
+  const Instruction *use_back() const { return cast<Instruction>(*use_begin());}
+  
+  /// getTerminator() - If this is a well formed basic block, then this returns
+  /// a pointer to the terminator instruction.  If it is not, then you get a
+  /// null pointer back.
+  ///
+  TerminatorInst *getTerminator();
+  const TerminatorInst *getTerminator() const;
+  
+  /// Returns a pointer to the first instructon in this block that is not a 
+  /// PHINode instruction. When adding instruction to the beginning of the
+  /// basic block, they should be added before the returned value, not before
+  /// the first instruction, which might be PHI.
+  /// Returns 0 is there's no non-PHI instruction.
+  Instruction* getFirstNonPHI();
+  const Instruction* getFirstNonPHI() const {
+    return const_cast<BasicBlock*>(this)->getFirstNonPHI();
+  }
+  
+  /// removeFromParent - This method unlinks 'this' from the containing
+  /// function, but does not delete it.
+  ///
+  void removeFromParent();
+
+  /// eraseFromParent - This method unlinks 'this' from the containing function
+  /// and deletes it.
+  ///
+  void eraseFromParent();
+  
+  /// moveBefore - Unlink this basic block from its current function and
+  /// insert it into the function that MovePos lives in, right before MovePos.
+  void moveBefore(BasicBlock *MovePos);
+  
+  /// moveAfter - Unlink this basic block from its current function and
+  /// insert it into the function that MovePos lives in, right after MovePos.
+  void moveAfter(BasicBlock *MovePos);
+  
+
+  /// getSinglePredecessor - If this basic block has a single predecessor block,
+  /// return the block, otherwise return a null pointer.
+  BasicBlock *getSinglePredecessor();
+  const BasicBlock *getSinglePredecessor() const {
+    return const_cast<BasicBlock*>(this)->getSinglePredecessor();
+  }
+
+  /// getUniquePredecessor - If this basic block has a unique predecessor block,
+  /// return the block, otherwise return a null pointer.
+  /// Note that unique predecessor doesn't mean single edge, there can be 
+  /// multiple edges from the unique predecessor to this block (for example 
+  /// a switch statement with multiple cases having the same destination).
+  BasicBlock *getUniquePredecessor();
+  const BasicBlock *getUniquePredecessor() const {
+    return const_cast<BasicBlock*>(this)->getUniquePredecessor();
+  }
+
+  //===--------------------------------------------------------------------===//
+  /// Instruction iterator methods
+  ///
+  inline iterator                begin()       { return InstList.begin(); }
+  inline const_iterator          begin() const { return InstList.begin(); }
+  inline iterator                end  ()       { return InstList.end();   }
+  inline const_iterator          end  () const { return InstList.end();   }
+
+  inline size_t                   size() const { return InstList.size();  }
+  inline bool                    empty() const { return InstList.empty(); }
+  inline const Instruction      &front() const { return InstList.front(); }
+  inline       Instruction      &front()       { return InstList.front(); }
+  inline const Instruction       &back() const { return InstList.back();  }
+  inline       Instruction       &back()       { return InstList.back();  }
+
+  /// getInstList() - Return the underlying instruction list container.  You
+  /// need to access it directly if you want to modify it currently.
+  ///
+  const InstListType &getInstList() const { return InstList; }
+        InstListType &getInstList()       { return InstList; }
+
+  /// getSublistAccess() - returns pointer to member of instruction list
+  static iplist<Instruction> BasicBlock::*getSublistAccess(Instruction*) {
+    return &BasicBlock::InstList;
+  }
+
+  /// getValueSymbolTable() - returns pointer to symbol table (if any)
+  ValueSymbolTable *getValueSymbolTable();
+
+  /// Methods for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const BasicBlock *) { return true; }
+  static inline bool classof(const Value *V) {
+    return V->getValueID() == Value::BasicBlockVal;
+  }
+
+  /// dropAllReferences() - This function causes all the subinstructions to "let
+  /// go" of all references that they are maintaining.  This allows one to
+  /// 'delete' a whole class at a time, even though there may be circular
+  /// references... first all references are dropped, and all use counts go to
+  /// zero.  Then everything is delete'd for real.  Note that no operations are
+  /// valid on an object that has "dropped all references", except operator
+  /// delete.
+  ///
+  void dropAllReferences();
+
+  /// removePredecessor - This method is used to notify a BasicBlock that the
+  /// specified Predecessor of the block is no longer able to reach it.  This is
+  /// actually not used to update the Predecessor list, but is actually used to
+  /// update the PHI nodes that reside in the block.  Note that this should be
+  /// called while the predecessor still refers to this block.
+  ///
+  void removePredecessor(BasicBlock *Pred, bool DontDeleteUselessPHIs = false);
+
+  /// splitBasicBlock - This splits a basic block into two at the specified
+  /// instruction.  Note that all instructions BEFORE the specified iterator
+  /// stay as part of the original basic block, an unconditional branch is added
+  /// to the original BB, and the rest of the instructions in the BB are moved
+  /// to the new BB, including the old terminator.  The newly formed BasicBlock
+  /// is returned.  This function invalidates the specified iterator.
+  ///
+  /// Note that this only works on well formed basic blocks (must have a
+  /// terminator), and 'I' must not be the end of instruction list (which would
+  /// cause a degenerate basic block to be formed, having a terminator inside of
+  /// the basic block).
+  ///
+  BasicBlock *splitBasicBlock(iterator I, const std::string &BBName = "");
+};
+
+} // End llvm namespace
+
+#endif