Move the source-level CFG from libAST to libAnalysis.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76092 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 1924 deletions

diff --git a/lib/AST/CFG.cpp b/lib/AST/CFG.cpp
deleted file mode 100644
index 69852f5fea..0000000000
--- a/lib/AST/CFG.cpp
+++ /dev/null
@@ -1,1924 +0,0 @@
-//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-//  This file defines the CFG and CFGBuilder classes for representing and
-//  building Control-Flow Graphs (CFGs) from ASTs.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/AST/CFG.h"
-#include "clang/AST/StmtVisitor.h"
-#include "clang/AST/PrettyPrinter.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/Support/GraphWriter.h"
-#include "llvm/Support/Streams.h"
-#include "llvm/Support/Compiler.h"
-#include <llvm/Support/Allocator.h>
-#include <llvm/Support/Format.h>
-
-using namespace clang;
-
-namespace {
-
-// SaveAndRestore - A utility class that uses RIIA to save and restore
-//  the value of a variable.
-template<typename T>
-struct VISIBILITY_HIDDEN SaveAndRestore {
-  SaveAndRestore(T& x) : X(x), old_value(x) {}
-  ~SaveAndRestore() { X = old_value; }
-  T get() { return old_value; }
-
-  T& X;
-  T old_value;
-};
-  
-static SourceLocation GetEndLoc(Decl* D) {
-  if (VarDecl* VD = dyn_cast<VarDecl>(D))
-    if (Expr* Ex = VD->getInit())
-      return Ex->getSourceRange().getEnd();
-  
-  return D->getLocation();  
-}
-  
-/// CFGBuilder - This class implements CFG construction from an AST.
-///   The builder is stateful: an instance of the builder should be used to only
-///   construct a single CFG.
-///
-///   Example usage:
-///
-///     CFGBuilder builder;
-///     CFG* cfg = builder.BuildAST(stmt1);
-///
-///  CFG construction is done via a recursive walk of an AST.
-///  We actually parse the AST in reverse order so that the successor
-///  of a basic block is constructed prior to its predecessor.  This
-///  allows us to nicely capture implicit fall-throughs without extra
-///  basic blocks.
-///
-class VISIBILITY_HIDDEN CFGBuilder : public StmtVisitor<CFGBuilder,CFGBlock*> {    
-  CFG* cfg;
-  CFGBlock* Block;
-  CFGBlock* Succ;
-  CFGBlock* ContinueTargetBlock;
-  CFGBlock* BreakTargetBlock;
-  CFGBlock* SwitchTerminatedBlock;
-  CFGBlock* DefaultCaseBlock;
-  
-  // LabelMap records the mapping from Label expressions to their blocks.
-  typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy;
-  LabelMapTy LabelMap;
-  
-  // A list of blocks that end with a "goto" that must be backpatched to
-  // their resolved targets upon completion of CFG construction.
-  typedef std::vector<CFGBlock*> BackpatchBlocksTy;
-  BackpatchBlocksTy BackpatchBlocks;
-  
-  // A list of labels whose address has been taken (for indirect gotos).
-  typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy;
-  LabelSetTy AddressTakenLabels;
-  
-public:  
-  explicit CFGBuilder() : cfg(NULL), Block(NULL), Succ(NULL),
-                          ContinueTargetBlock(NULL), BreakTargetBlock(NULL),
-                          SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL) {
-    // Create an empty CFG.
-    cfg = new CFG();                        
-  }
-  
-  ~CFGBuilder() { delete cfg; }
-  
-  // buildCFG - Used by external clients to construct the CFG.
-  CFG* buildCFG(Stmt* Statement);
-  
-  // Visitors to walk an AST and construct the CFG.  Called by
-  // buildCFG.  Do not call directly!
-  
-  CFGBlock* VisitBreakStmt(BreakStmt* B);
-  CFGBlock* VisitCaseStmt(CaseStmt* Terminator);
-  CFGBlock* VisitCompoundStmt(CompoundStmt* C);
-  CFGBlock* VisitContinueStmt(ContinueStmt* C);
-  CFGBlock* VisitDefaultStmt(DefaultStmt* D);
-  CFGBlock* VisitDoStmt(DoStmt* D);
-  CFGBlock* VisitForStmt(ForStmt* F);
-  CFGBlock* VisitGotoStmt(GotoStmt* G);
-  CFGBlock* VisitIfStmt(IfStmt* I);
-  CFGBlock* VisitIndirectGotoStmt(IndirectGotoStmt* I);
-  CFGBlock* VisitLabelStmt(LabelStmt* L);
-  CFGBlock* VisitNullStmt(NullStmt* Statement);
-  CFGBlock* VisitObjCForCollectionStmt(ObjCForCollectionStmt* S);
-  CFGBlock* VisitReturnStmt(ReturnStmt* R);
-  CFGBlock* VisitStmt(Stmt* Statement);
-  CFGBlock* VisitSwitchStmt(SwitchStmt* Terminator);
-  CFGBlock* VisitWhileStmt(WhileStmt* W);
-  
-  // FIXME: Add support for ObjC-specific control-flow structures.
-  
-  // NYS == Not Yet Supported
-  CFGBlock* NYS() {
-    badCFG = true;
-    return Block;
-  }
-  
-  CFGBlock* VisitObjCAtTryStmt(ObjCAtTryStmt* S);
-  CFGBlock* VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 
-    // FIXME: For now we pretend that @catch and the code it contains
-    //  does not exit.
-    return Block;
-  }
-
-  // FIXME: This is not completely supported.  We basically @throw like
-  // a 'return'.
-  CFGBlock* VisitObjCAtThrowStmt(ObjCAtThrowStmt* S);
-
-  CFGBlock* VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S);
-  
-  // Blocks.
-  CFGBlock* VisitBlockExpr(BlockExpr* E) { return NYS(); }
-  CFGBlock* VisitBlockDeclRefExpr(BlockDeclRefExpr* E) { return NYS(); }  
-  
-private:
-  CFGBlock* createBlock(bool add_successor = true);
-  CFGBlock* addStmt(Stmt* Terminator);
-  CFGBlock* WalkAST(Stmt* Terminator, bool AlwaysAddStmt);
-  CFGBlock* WalkAST_VisitChildren(Stmt* Terminator);
-  CFGBlock* WalkAST_VisitDeclSubExpr(Decl* D);
-  CFGBlock* WalkAST_VisitStmtExpr(StmtExpr* Terminator);
-  bool FinishBlock(CFGBlock* B);
-  
-  bool badCFG;
-};
-  
-// FIXME: Add support for dependent-sized array types in C++?
-// Does it even make sense to build a CFG for an uninstantiated template?
-static VariableArrayType* FindVA(Type* t) {
-  while (ArrayType* vt = dyn_cast<ArrayType>(t)) {
-    if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt))
-      if (vat->getSizeExpr())
-        return vat;
-    
-    t = vt->getElementType().getTypePtr();
-  }
-  
-  return 0;
-}
-    
-/// BuildCFG - Constructs a CFG from an AST (a Stmt*).  The AST can
-///  represent an arbitrary statement.  Examples include a single expression
-///  or a function body (compound statement).  The ownership of the returned
-///  CFG is transferred to the caller.  If CFG construction fails, this method
-///  returns NULL.
-CFG* CFGBuilder::buildCFG(Stmt* Statement) {
-  assert (cfg);
-  if (!Statement) return NULL;
-
-  badCFG = false;
-  
-  // Create an empty block that will serve as the exit block for the CFG.
-  // Since this is the first block added to the CFG, it will be implicitly
-  // registered as the exit block.
-  Succ = createBlock();
-  assert (Succ == &cfg->getExit());
-  Block = NULL;  // the EXIT block is empty.  Create all other blocks lazily.
-  
-  // Visit the statements and create the CFG.
-  CFGBlock* B = Visit(Statement);
-  if (!B) B = Succ;
-  
-  if (B) {
-    // Finalize the last constructed block.  This usually involves
-    // reversing the order of the statements in the block.
-    if (Block) FinishBlock(B);
-    
-    // Backpatch the gotos whose label -> block mappings we didn't know
-    // when we encountered them.
-    for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 
-         E = BackpatchBlocks.end(); I != E; ++I ) {
-     
-      CFGBlock* B = *I;
-      GotoStmt* G = cast<GotoStmt>(B->getTerminator());
-      LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
-
-      // If there is no target for the goto, then we are looking at an
-      // incomplete AST.  Handle this by not registering a successor.
-      if (LI == LabelMap.end()) continue;
-      
-      B->addSuccessor(LI->second);                   
-    }
-    
-    // Add successors to the Indirect Goto Dispatch block (if we have one).
-    if (CFGBlock* B = cfg->getIndirectGotoBlock())
-      for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
-           E = AddressTakenLabels.end(); I != E; ++I ) {
-
-        // Lookup the target block.
-        LabelMapTy::iterator LI = LabelMap.find(*I);
-
-        // If there is no target block that contains label, then we are looking
-        // at an incomplete AST.  Handle this by not registering a successor.
-        if (LI == LabelMap.end()) continue;
-        
-        B->addSuccessor(LI->second);           
-      }
-                                                          
-    Succ = B;
-  }
-  
-  // Create an empty entry block that has no predecessors.    
-  cfg->setEntry(createBlock());
-    
-  if (badCFG) {
-    delete cfg;
-    cfg = NULL;
-    return NULL;
-  }
-    
-  // NULL out cfg so that repeated calls to the builder will fail and that
-  // the ownership of the constructed CFG is passed to the caller.
-  CFG* t = cfg;
-  cfg = NULL;
-  return t;
-}
-  
-/// createBlock - Used to lazily create blocks that are connected
-///  to the current (global) succcessor.
-CFGBlock* CFGBuilder::createBlock(bool add_successor) { 
-  CFGBlock* B = cfg->createBlock();
-  if (add_successor && Succ) B->addSuccessor(Succ);
-  return B;
-}
-  
-/// FinishBlock - When the last statement has been added to the block,
-///  we must reverse the statements because they have been inserted
-///  in reverse order.
-bool CFGBuilder::FinishBlock(CFGBlock* B) {
-  if (badCFG)
-    return false;
-
-  assert (B);
-  B->reverseStmts();
-  return true;
-}
-
-/// addStmt - Used to add statements/expressions to the current CFGBlock 
-///  "Block".  This method calls WalkAST on the passed statement to see if it
-///  contains any short-circuit expressions.  If so, it recursively creates
-///  the necessary blocks for such expressions.  It returns the "topmost" block
-///  of the created blocks, or the original value of "Block" when this method
-///  was called if no additional blocks are created.
-CFGBlock* CFGBuilder::addStmt(Stmt* Terminator) {
-  if (!Block) Block = createBlock();
-  return WalkAST(Terminator,true);
-}
-
-/// WalkAST - Used by addStmt to walk the subtree of a statement and
-///   add extra blocks for ternary operators, &&, and ||.  We also
-///   process "," and DeclStmts (which may contain nested control-flow).
-CFGBlock* CFGBuilder::WalkAST(Stmt* Terminator, bool AlwaysAddStmt = false) {    
-  switch (Terminator->getStmtClass()) {
-    case Stmt::ConditionalOperatorClass: {
-      ConditionalOperator* C = cast<ConditionalOperator>(Terminator);
-
-      // Create the confluence block that will "merge" the results
-      // of the ternary expression.
-      CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();  
-      ConfluenceBlock->appendStmt(C);
-      if (!FinishBlock(ConfluenceBlock))
-        return 0;
-
-      // Create a block for the LHS expression if there is an LHS expression.
-      // A GCC extension allows LHS to be NULL, causing the condition to
-      // be the value that is returned instead.
-      //  e.g: x ?: y is shorthand for: x ? x : y;
-      Succ = ConfluenceBlock;
-      Block = NULL;
-      CFGBlock* LHSBlock = NULL;
-      if (C->getLHS()) {
-        LHSBlock = Visit(C->getLHS());
-        if (!FinishBlock(LHSBlock))
-          return 0;
-        Block = NULL;        
-      }
-      
-      // Create the block for the RHS expression.
-      Succ = ConfluenceBlock;
-      CFGBlock* RHSBlock = Visit(C->getRHS());
-      if (!FinishBlock(RHSBlock))
-        return 0;
-
-      // Create the block that will contain the condition.
-      Block = createBlock(false);
-      
-      if (LHSBlock)
-        Block->addSuccessor(LHSBlock);
-      else {
-        // If we have no LHS expression, add the ConfluenceBlock as a direct
-        // successor for the block containing the condition.  Moreover,
-        // we need to reverse the order of the predecessors in the
-        // ConfluenceBlock because the RHSBlock will have been added to
-        // the succcessors already, and we want the first predecessor to the
-        // the block containing the expression for the case when the ternary
-        // expression evaluates to true.
-        Block->addSuccessor(ConfluenceBlock);
-        assert (ConfluenceBlock->pred_size() == 2);
-        std::reverse(ConfluenceBlock->pred_begin(), 
-                     ConfluenceBlock->pred_end());
-      }
-      
-      Block->addSuccessor(RHSBlock);
-      
-      Block->setTerminator(C);
-      return addStmt(C->getCond());
-    }
-    
-    case Stmt::ChooseExprClass: {
-      ChooseExpr* C = cast<ChooseExpr>(Terminator);      
-      
-      CFGBlock* ConfluenceBlock = Block ? Block : createBlock();  
-      ConfluenceBlock->appendStmt(C);
-      if (!FinishBlock(ConfluenceBlock))
-        return 0;
-      
-      Succ = ConfluenceBlock;
-      Block = NULL;
-      CFGBlock* LHSBlock = Visit(C->getLHS());
-      if (!FinishBlock(LHSBlock))
-        return 0;
-
-      Succ = ConfluenceBlock;
-      Block = NULL;
-      CFGBlock* RHSBlock = Visit(C->getRHS());
-      if (!FinishBlock(RHSBlock))
-        return 0;
-      
-      Block = createBlock(false);
-      Block->addSuccessor(LHSBlock);
-      Block->addSuccessor(RHSBlock);
-      Block->setTerminator(C);
-      return addStmt(C->getCond());
-    }
-
-    case Stmt::DeclStmtClass: {
-      DeclStmt *DS = cast<DeclStmt>(Terminator);      
-      if (DS->isSingleDecl()) {      
-        Block->appendStmt(Terminator);
-        return WalkAST_VisitDeclSubExpr(DS->getSingleDecl());
-      }
-      
-      CFGBlock* B = 0;
-
-      // FIXME: Add a reverse iterator for DeclStmt to avoid this
-      // extra copy.
-      typedef llvm::SmallVector<Decl*,10> BufTy;
-      BufTy Buf(DS->decl_begin(), DS->decl_end());
-      
-      for (BufTy::reverse_iterator I=Buf.rbegin(), E=Buf.rend(); I!=E; ++I) {
-        // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
-        unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8
-                     ? 8 : llvm::AlignOf<DeclStmt>::Alignment;
-        
-        // Allocate the DeclStmt using the BumpPtrAllocator.  It will
-        // get automatically freed with the CFG. 
-        DeclGroupRef DG(*I);
-        Decl* D = *I;
-        void* Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
-        
-        DeclStmt* DS = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
-        
-        // Append the fake DeclStmt to block.
-        Block->appendStmt(DS);
-        B = WalkAST_VisitDeclSubExpr(D);
-      }
-      return B;
-    }
-
-    case Stmt::AddrLabelExprClass: {
-      AddrLabelExpr* A = cast<AddrLabelExpr>(Terminator);
-      AddressTakenLabels.insert(A->getLabel());
-      
-      if (AlwaysAddStmt) Block->appendStmt(Terminator);
-      return Block;
-    }
-    
-    case Stmt::StmtExprClass:
-      return WalkAST_VisitStmtExpr(cast<StmtExpr>(Terminator));
-
-    case Stmt::SizeOfAlignOfExprClass: {
-      SizeOfAlignOfExpr* E = cast<SizeOfAlignOfExpr>(Terminator);
-
-      // VLA types have expressions that must be evaluated.
-      if (E->isArgumentType()) {
-        for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr());
-             VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
-          addStmt(VA->getSizeExpr());
-      }
-      // Expressions in sizeof/alignof are not evaluated and thus have no
-      // control flow.
-      else
-        Block->appendStmt(Terminator);
-
-      return Block;
-    }
-      
-    case Stmt::BinaryOperatorClass: {
-      BinaryOperator* B = cast<BinaryOperator>(Terminator);
-
-      if (B->isLogicalOp()) { // && or ||
-        CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();  
-        ConfluenceBlock->appendStmt(B);
-        if (!FinishBlock(ConfluenceBlock))
-          return 0;
-
-        // create the block evaluating the LHS
-        CFGBlock* LHSBlock = createBlock(false);
-        LHSBlock->setTerminator(B);
-        
-        // create the block evaluating the RHS
-        Succ = ConfluenceBlock;
-        Block = NULL;
-        CFGBlock* RHSBlock = Visit(B->getRHS());
-        if (!FinishBlock(RHSBlock))
-          return 0;
-
-        // Now link the LHSBlock with RHSBlock.
-        if (B->getOpcode() == BinaryOperator::LOr) {
-          LHSBlock->addSuccessor(ConfluenceBlock);
-          LHSBlock->addSuccessor(RHSBlock);
-        }
-        else {
-          assert (B->getOpcode() == BinaryOperator::LAnd);
-          LHSBlock->addSuccessor(RHSBlock);
-          LHSBlock->addSuccessor(ConfluenceBlock);
-        }
-        
-        // Generate the blocks for evaluating the LHS.
-        Block = LHSBlock;
-        return addStmt(B->getLHS());                                    
-      }
-      else if (B->getOpcode() == BinaryOperator::Comma) { // ,
-        Block->appendStmt(B);
-        addStmt(B->getRHS());
-        return addStmt(B->getLHS());
-      }
-      
-      break;
-    }
-    
-    // Blocks: No support for blocks ... yet
-    case Stmt::BlockExprClass:
-    case Stmt::BlockDeclRefExprClass:
-      return NYS();
-      
-    case Stmt::ParenExprClass:
-      return WalkAST(cast<ParenExpr>(Terminator)->getSubExpr(), AlwaysAddStmt);
-    
-    default:
-      break;
-  };
-      
-  if (AlwaysAddStmt) Block->appendStmt(Terminator);
-  return WalkAST_VisitChildren(Terminator);
-}
-  
-/// WalkAST_VisitDeclSubExpr - Utility method to add block-level expressions
-///  for initializers in Decls.
-CFGBlock* CFGBuilder::WalkAST_VisitDeclSubExpr(Decl* D) {
-  VarDecl* VD = dyn_cast<VarDecl>(D);
-
-  if (!VD)
-    return Block;
-  
-  Expr* Init = VD->getInit();
-  
-  if (Init) {
-    // Optimization: Don't create separate block-level statements for literals.
-    switch (Init->getStmtClass()) {
-      case Stmt::IntegerLiteralClass:
-      case Stmt::CharacterLiteralClass:
-      case Stmt::StringLiteralClass:
-        break;
-      default:
-        Block = addStmt(Init);
-    }
-  }
-    
-  // If the type of VD is a VLA, then we must process its size expressions.
-  for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0;
-       VA = FindVA(VA->getElementType().getTypePtr()))
-    Block = addStmt(VA->getSizeExpr());  
-  
-  return Block;
-}
-
-/// WalkAST_VisitChildren - Utility method to call WalkAST on the
-///  children of a Stmt.
-CFGBlock* CFGBuilder::WalkAST_VisitChildren(Stmt* Terminator) {
-  CFGBlock* B = Block;
-  for (Stmt::child_iterator I = Terminator->child_begin(),
-         E = Terminator->child_end();
-       I != E; ++I)
-    if (*I) B = WalkAST(*I);
-  
-  return B;
-}
-
-/// WalkAST_VisitStmtExpr - Utility method to handle (nested) statement
-///  expressions (a GCC extension).
-CFGBlock* CFGBuilder::WalkAST_VisitStmtExpr(StmtExpr* Terminator) {
-  Block->appendStmt(Terminator);
-  return VisitCompoundStmt(Terminator->getSubStmt());  
-}
-
-/// VisitStmt - Handle statements with no branching control flow.
-CFGBlock* CFGBuilder::VisitStmt(Stmt* Statement) {
-  // We cannot assume that we are in the middle of a basic block, since
-  // the CFG might only be constructed for this single statement.  If
-  // we have no current basic block, just create one lazily.
-  if (!Block) Block = createBlock();
-  
-  // Simply add the statement to the current block.  We actually
-  // insert statements in reverse order; this order is reversed later
-  // when processing the containing element in the AST.
-  addStmt(Statement);
-
-  return Block;
-}
-
-CFGBlock* CFGBuilder::VisitNullStmt(NullStmt* Statement) {
-  return Block;
-}
-
-CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) {
-  
-  CFGBlock* LastBlock = Block;
-
-  for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
-                                                               I != E; ++I ) {
-    LastBlock = Visit(*I);
-  }
-
-  return LastBlock;
-}
-
-CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) {
-  // We may see an if statement in the middle of a basic block, or
-  // it may be the first statement we are processing.  In either case,
-  // we create a new basic block.  First, we create the blocks for
-  // the then...else statements, and then we create the block containing
-  // the if statement.  If we were in the middle of a block, we
-  // stop processing that block and reverse its statements.  That block
-  // is then the implicit successor for the "then" and "else" clauses.
-  
-  // The block we were proccessing is now finished.  Make it the
-  // successor block.
-  if (Block) { 
-    Succ = Block;
-    if (!FinishBlock(Block))
-      return 0;
-  }
-  
-  // Process the false branch.  NULL out Block so that the recursive
-  // call to Visit will create a new basic block.
-  // Null out Block so that all successor
-  CFGBlock* ElseBlock = Succ;
-  
-  if (Stmt* Else = I->getElse()) {
-    SaveAndRestore<CFGBlock*> sv(Succ);
-    
-    // NULL out Block so that the recursive call to Visit will
-    // create a new basic block.          
-    Block = NULL;
-    ElseBlock = Visit(Else);
-              
-    if (!ElseBlock) // Can occur when the Else body has all NullStmts.
-      ElseBlock = sv.get();
-    else if (Block) {
-      if (!FinishBlock(ElseBlock))
-        return 0;
-    }
-  }
-  
-  // Process the true branch.  NULL out Block so that the recursive
-  // call to Visit will create a new basic block.
-  // Null out Block so that all successor
-  CFGBlock* ThenBlock;
-  {
-    Stmt* Then = I->getThen();
-    assert (Then);
-    SaveAndRestore<CFGBlock*> sv(Succ);
-    Block = NULL;        
-    ThenBlock = Visit(Then);
-    
-    if (!ThenBlock) {
-      // We can reach here if the "then" body has all NullStmts.
-      // Create an empty block so we can distinguish between true and false
-      // branches in path-sensitive analyses.
-      ThenBlock = createBlock(false);
-      ThenBlock->addSuccessor(sv.get());
-    }
-    else if (Block) {
-      if (!FinishBlock(ThenBlock))
-        return 0;
-    }        
-  }
-
-  // Now create a new block containing the if statement.        
-  Block = createBlock(false);
-  
-  // Set the terminator of the new block to the If statement.
-  Block->setTerminator(I);
-  
-  // Now add the successors.
-  Block->addSuccessor(ThenBlock);
-  Block->addSuccessor(ElseBlock);
-  
-  // Add the condition as the last statement in the new block.  This
-  // may create new blocks as the condition may contain control-flow.  Any
-  // newly created blocks will be pointed to be "Block".
-  return addStmt(I->getCond()->IgnoreParens());
-}
-  
-    
-CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) {
-  // If we were in the middle of a block we stop processing that block
-  // and reverse its statements.
-  //
-  // NOTE: If a "return" appears in the middle of a block, this means
-  //       that the code afterwards is DEAD (unreachable).  We still
-  //       keep a basic block for that code; a simple "mark-and-sweep"
-  //       from the entry block will be able to report such dead
-  //       blocks.
-  if (Block) FinishBlock(Block);
-
-  // Create the new block.
-  Block = createBlock(false);
-  
-  // The Exit block is the only successor.
-  Block->addSuccessor(&cfg->getExit());
-    
-  // Add the return statement to the block.  This may create new blocks
-  // if R contains control-flow (short-circuit operations).
-  return addStmt(R);
-}
-
-CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) {
-  // Get the block of the labeled statement.  Add it to our map.
-  Visit(L->getSubStmt());
-  CFGBlock* LabelBlock = Block;
-  
-  if (!LabelBlock)            // This can happen when the body is empty, i.e.
-    LabelBlock=createBlock(); // scopes that only contains NullStmts.
-  
-  assert (LabelMap.find(L) == LabelMap.end() && "label already in map");
-  LabelMap[ L ] = LabelBlock;
-  
-  // Labels partition blocks, so this is the end of the basic block
-  // we were processing (L is the block's label).  Because this is
-  // label (and we have already processed the substatement) there is no
-  // extra control-flow to worry about.
-  LabelBlock->setLabel(L);
-  if (!FinishBlock(LabelBlock))
-    return 0;
-  
-  // We set Block to NULL to allow lazy creation of a new block
-  // (if necessary);
-  Block = NULL;
-  
-  // This block is now the implicit successor of other blocks.
-  Succ = LabelBlock;
-  
-  return LabelBlock;
-}
-
-CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) {
-  // Goto is a control-flow statement.  Thus we stop processing the
-  // current block and create a new one.
-  if (Block) FinishBlock(Block);
-  Block = createBlock(false);
-  Block->setTerminator(G);
-  
-  // If we already know the mapping to the label block add the
-  // successor now.
-  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
-  
-  if (I == LabelMap.end())
-    // We will need to backpatch this block later.
-    BackpatchBlocks.push_back(Block);
-  else
-    Block->addSuccessor(I->second);
-
-  return Block;            
-}
-
-CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) {
-  // "for" is a control-flow statement.  Thus we stop processing the
-  // current block.
-  
-  CFGBlock* LoopSuccessor = NULL;
-  
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-    LoopSuccessor = Block;
-  }
-  else LoopSuccessor = Succ;
-  
-  // Because of short-circuit evaluation, the condition of the loop
-  // can span multiple basic blocks.  Thus we need the "Entry" and "Exit"
-  // blocks that evaluate the condition.
-  CFGBlock* ExitConditionBlock = createBlock(false);
-  CFGBlock* EntryConditionBlock = ExitConditionBlock;
-  
-  // Set the terminator for the "exit" condition block.
-  ExitConditionBlock->setTerminator(F);  
-  
-  // Now add the actual condition to the condition block.  Because the
-  // condition itself may contain control-flow, new blocks may be created.
-  if (Stmt* C = F->getCond()) {
-    Block = ExitConditionBlock;
-    EntryConditionBlock = addStmt(C);
-    if (Block) {
-      if (!FinishBlock(EntryConditionBlock))
-        return 0;
-    }
-  }
-
-  // The condition block is the implicit successor for the loop body as
-  // well as any code above the loop.
-  Succ = EntryConditionBlock;
-  
-  // Now create the loop body.
-  {
-    assert (F->getBody());
-    
-    // Save the current values for Block, Succ, and continue and break targets
-    SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
-    save_continue(ContinueTargetBlock),
-    save_break(BreakTargetBlock);      
- 
-    // Create a new block to contain the (bottom) of the loop body.
-    Block = NULL;
-    
-    if (Stmt* I = F->getInc()) {
-      // Generate increment code in its own basic block.  This is the target
-      // of continue statements.
-      Succ = Visit(I);
-    }
-    else {
-      // No increment code.  Create a special, empty, block that is used as
-      // the target block for "looping back" to the start of the loop.
-      assert(Succ == EntryConditionBlock);
-      Succ = createBlock();
-    }
-    
-    // Finish up the increment (or empty) block if it hasn't been already.
-    if (Block) {
-      assert(Block == Succ);
-      if (!FinishBlock(Block))
-        return 0;
-      Block = 0;
-    }
-    
-    ContinueTargetBlock = Succ;
-    
-    // The starting block for the loop increment is the block that should
-    // represent the 'loop target' for looping back to the start of the loop.
-    ContinueTargetBlock->setLoopTarget(F);
-
-    // All breaks should go to the code following the loop.
-    BreakTargetBlock = LoopSuccessor;    
-    
-    // Now populate the body block, and in the process create new blocks
-    // as we walk the body of the loop.
-    CFGBlock* BodyBlock = Visit(F->getBody());      
-
-    if (!BodyBlock)
-      BodyBlock = EntryConditionBlock; // can happen for "for (...;...; ) ;"
-    else if (Block) {
-      if (!FinishBlock(BodyBlock))
-        return 0;
-    }      
-    
-    // This new body block is a successor to our "exit" condition block.
-    ExitConditionBlock->addSuccessor(BodyBlock);
-  }
-  
-  // Link up the condition block with the code that follows the loop.
-  // (the false branch).
-  ExitConditionBlock->addSuccessor(LoopSuccessor);
-  
-  // If the loop contains initialization, create a new block for those
-  // statements.  This block can also contain statements that precede
-  // the loop.
-  if (Stmt* I = F->getInit()) {
-    Block = createBlock();
-    return addStmt(I);
-  }
-  else {
-    // There is no loop initialization.   We are thus basically a while 
-    // loop.  NULL out Block to force lazy block construction.
-    Block = NULL;
-    Succ = EntryConditionBlock;
-    return EntryConditionBlock;
-  }
-}
-
-CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) {
-  // Objective-C fast enumeration 'for' statements:
-  //  http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
-  //
-  //  for ( Type newVariable in collection_expression ) { statements }
-  //
-  //  becomes:
-  //
-  //   prologue:
-  //     1. collection_expression
-  //     T. jump to loop_entry
-  //   loop_entry:
-  //     1. side-effects of element expression
-  //     1. ObjCForCollectionStmt [performs binding to newVariable]
-  //     T. ObjCForCollectionStmt  TB, FB  [jumps to TB if newVariable != nil]
-  //   TB:
-  //     statements
-  //     T. jump to loop_entry
-  //   FB:
-  //     what comes after
-  //
-  //  and
-  //
-  //  Type existingItem;
-  //  for ( existingItem in expression ) { statements }
-  //
-  //  becomes:
-  //
-  //   the same with newVariable replaced with existingItem; the binding
-  //   works the same except that for one ObjCForCollectionStmt::getElement()
-  //   returns a DeclStmt and the other returns a DeclRefExpr.
-  //
-  
-  CFGBlock* LoopSuccessor = 0;
-  
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-    LoopSuccessor = Block;
-    Block = 0;
-  }
-  else LoopSuccessor = Succ;
-  
-  // Build the condition blocks.
-  CFGBlock* ExitConditionBlock = createBlock(false);
-  CFGBlock* EntryConditionBlock = ExitConditionBlock;
-  
-  // Set the terminator for the "exit" condition block.
-  ExitConditionBlock->setTerminator(S);  
-  
-  // The last statement in the block should be the ObjCForCollectionStmt,
-  // which performs the actual binding to 'element' and determines if there
-  // are any more items in the collection.
-  ExitConditionBlock->appendStmt(S);
-  Block = ExitConditionBlock;
-  
-  // Walk the 'element' expression to see if there are any side-effects.  We
-  // generate new blocks as necesary.  We DON'T add the statement by default
-  // to the CFG unless it contains control-flow.
-  EntryConditionBlock = WalkAST(S->getElement(), false);
-  if (Block) { 
-    if (!FinishBlock(EntryConditionBlock))
-      return 0;
-    Block = 0;
-  }
-  
-  // The condition block is the implicit successor for the loop body as
-  // well as any code above the loop.
-  Succ = EntryConditionBlock;
-  
-  // Now create the true branch.
-  { 
-    // Save the current values for Succ, continue and break targets.
-    SaveAndRestore<CFGBlock*> save_Succ(Succ),
-      save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 
-    
-    BreakTargetBlock = LoopSuccessor;
-    ContinueTargetBlock = EntryConditionBlock;  
-    
-    CFGBlock* BodyBlock = Visit(S->getBody());
-    
-    if (!BodyBlock)
-      BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
-    else if (Block) {
-      if (!FinishBlock(BodyBlock))
-        return 0;
-    }
-                  
-    // This new body block is a successor to our "exit" condition block.
-    ExitConditionBlock->addSuccessor(BodyBlock);
-  }
-  
-  // Link up the condition block with the code that follows the loop.
-  // (the false branch).
-  ExitConditionBlock->addSuccessor(LoopSuccessor);
-
-  // Now create a prologue block to contain the collection expression.
-  Block = createBlock();
-  return addStmt(S->getCollection());
-}    
-  
-CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) {
-  // FIXME: Add locking 'primitives' to CFG for @synchronized.
-  
-  // Inline the body.
-  CFGBlock *SyncBlock = Visit(S->getSynchBody());
-  
-  // The sync body starts its own basic block.  This makes it a little easier
-  // for diagnostic clients.
-  if (SyncBlock) {
-    if (!FinishBlock(SyncBlock))
-      return 0;
-    
-    Block = 0;
-  }
-    
-  Succ = SyncBlock;
-  
-  // Inline the sync expression.
-  return Visit(S->getSynchExpr());
-}
-  
-CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) {
-  return NYS();
-}
-
-CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) {
-  // "while" is a control-flow statement.  Thus we stop processing the
-  // current block.
-  
-  CFGBlock* LoopSuccessor = NULL;
-  
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-    LoopSuccessor = Block;
-  }
-  else LoopSuccessor = Succ;
-            
-  // Because of short-circuit evaluation, the condition of the loop
-  // can span multiple basic blocks.  Thus we need the "Entry" and "Exit"
-  // blocks that evaluate the condition.
-  CFGBlock* ExitConditionBlock = createBlock(false);
-  CFGBlock* EntryConditionBlock = ExitConditionBlock;
-  
-  // Set the terminator for the "exit" condition block.
-  ExitConditionBlock->setTerminator(W);
-  
-  // Now add the actual condition to the condition block.  Because the
-  // condition itself may contain control-flow, new blocks may be created.
-  // Thus we update "Succ" after adding the condition.
-  if (Stmt* C = W->getCond()) {
-    Block = ExitConditionBlock;
-    EntryConditionBlock = addStmt(C);
-    assert(Block == EntryConditionBlock);
-    if (Block) {
-      if (!FinishBlock(EntryConditionBlock))
-        return 0;
-    }
-  }
-  
-  // The condition block is the implicit successor for the loop body as
-  // well as any code above the loop.
-  Succ = EntryConditionBlock;
-  
-  // Process the loop body.
-  {
-    assert(W->getBody());
-
-    // Save the current values for Block, Succ, and continue and break targets
-    SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
-                              save_continue(ContinueTargetBlock),
-                              save_break(BreakTargetBlock);
-
-    // Create an empty block to represent the transition block for looping
-    // back to the head of the loop.
-    Block = 0;
-    assert(Succ == EntryConditionBlock);
-    Succ = createBlock();
-    Succ->setLoopTarget(W);
-    ContinueTargetBlock = Succ;    
-    
-    // All breaks should go to the code following the loop.
-    BreakTargetBlock = LoopSuccessor;
-    
-    // NULL out Block to force lazy instantiation of blocks for the body.
-    Block = NULL;
-    
-    // Create the body.  The returned block is the entry to the loop body.
-    CFGBlock* BodyBlock = Visit(W->getBody());
-    
-    if (!BodyBlock)
-      BodyBlock = EntryConditionBlock; // can happen for "while(...) ;"
-    else if (Block) {
-      if (!FinishBlock(BodyBlock))
-        return 0;
-    }
-    
-    // Add the loop body entry as a successor to the condition.
-    ExitConditionBlock->addSuccessor(BodyBlock);
-  }
-  
-  // Link up the condition block with the code that follows the loop.
-  // (the false branch).
-  ExitConditionBlock->addSuccessor(LoopSuccessor);
-  
-  // There can be no more statements in the condition block
-  // since we loop back to this block.  NULL out Block to force
-  // lazy creation of another block.
-  Block = NULL;
-  
-  // Return the condition block, which is the dominating block for the loop.
-  Succ = EntryConditionBlock;
-  return EntryConditionBlock;
-}
-  
-CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) {
-  // FIXME: This isn't complete.  We basically treat @throw like a return
-  //  statement.
-  
-  // If we were in the middle of a block we stop processing that block
-  // and reverse its statements.
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-  }
-  
-  // Create the new block.
-  Block = createBlock(false);
-  
-  // The Exit block is the only successor.
-  Block->addSuccessor(&cfg->getExit());
-  
-  // Add the statement to the block.  This may create new blocks
-  // if S contains control-flow (short-circuit operations).
-  return addStmt(S);
-}
-
-CFGBlock* CFGBuilder::VisitDoStmt(DoStmt* D) {
-  // "do...while" is a control-flow statement.  Thus we stop processing the
-  // current block.
-  
-  CFGBlock* LoopSuccessor = NULL;
-  
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-    LoopSuccessor = Block;
-  }
-  else LoopSuccessor = Succ;
-  
-  // Because of short-circuit evaluation, the condition of the loop
-  // can span multiple basic blocks.  Thus we need the "Entry" and "Exit"
-  // blocks that evaluate the condition.
-  CFGBlock* ExitConditionBlock = createBlock(false);
-  CFGBlock* EntryConditionBlock = ExitConditionBlock;
-        
-  // Set the terminator for the "exit" condition block.
-  ExitConditionBlock->setTerminator(D);  
-  
-  // Now add the actual condition to the condition block.  Because the
-  // condition itself may contain control-flow, new blocks may be created.
-  if (Stmt* C = D->getCond()) {
-    Block = ExitConditionBlock;
-    EntryConditionBlock = addStmt(C);
-    if (Block) {
-      if (!FinishBlock(EntryConditionBlock))
-        return 0;
-    }
-  }
-  
-  // The condition block is the implicit successor for the loop body.
-  Succ = EntryConditionBlock;
-
-  // Process the loop body.
-  CFGBlock* BodyBlock = NULL;
-  {
-    assert (D->getBody());
-    
-    // Save the current values for Block, Succ, and continue and break targets
-    SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
-    save_continue(ContinueTargetBlock),
-    save_break(BreakTargetBlock);
-    
-    // All continues within this loop should go to the condition block
-    ContinueTargetBlock = EntryConditionBlock;
-    
-    // All breaks should go to the code following the loop.
-    BreakTargetBlock = LoopSuccessor;
-    
-    // NULL out Block to force lazy instantiation of blocks for the body.
-    Block = NULL;
-    
-    // Create the body.  The returned block is the entry to the loop body.
-    BodyBlock = Visit(D->getBody());
-    
-    if (!BodyBlock)
-      BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
-    else if (Block) {
-      if (!FinishBlock(BodyBlock))
-        return 0;
-    }
-        
-    // Add an intermediate block between the BodyBlock and the
-    // ExitConditionBlock to represent the "loop back" transition.
-    // Create an empty block to represent the transition block for looping
-    // back to the head of the loop.
-    // FIXME: Can we do this more efficiently without adding another block?
-    Block = NULL;
-    Succ = BodyBlock;
-    CFGBlock *LoopBackBlock = createBlock();
-    LoopBackBlock->setLoopTarget(D);
-    
-    // Add the loop body entry as a successor to the condition.
-    ExitConditionBlock->addSuccessor(LoopBackBlock);
-  }
-  
-  // Link up the condition block with the code that follows the loop.
-  // (the false branch).
-  ExitConditionBlock->addSuccessor(LoopSuccessor);
-  
-  // There can be no more statements in the body block(s)
-  // since we loop back to the body.  NULL out Block to force
-  // lazy creation of another block.
-  Block = NULL;
-  
-  // Return the loop body, which is the dominating block for the loop.
-  Succ = BodyBlock;
-  return BodyBlock;
-}
-
-CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) {
-  // "continue" is a control-flow statement.  Thus we stop processing the
-  // current block.
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-  }
-  
-  // Now create a new block that ends with the continue statement.
-  Block = createBlock(false);
-  Block->setTerminator(C);
-  
-  // If there is no target for the continue, then we are looking at an
-  // incomplete AST.  This means the CFG cannot be constructed.
-  if (ContinueTargetBlock)
-    Block->addSuccessor(ContinueTargetBlock);
-  else
-    badCFG = true;
-  
-  return Block;
-}
-
-CFGBlock* CFGBuilder::VisitBreakStmt(BreakStmt* B) {
-  // "break" is a control-flow statement.  Thus we stop processing the
-  // current block.
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-  }
-  
-  // Now create a new block that ends with the continue statement.
-  Block = createBlock(false);
-  Block->setTerminator(B);
-  
-  // If there is no target for the break, then we are looking at an
-  // incomplete AST.  This means that the CFG cannot be constructed.
-  if (BreakTargetBlock)
-    Block->addSuccessor(BreakTargetBlock);
-  else 
-    badCFG = true;
-
-
-  return Block;  
-}
-
-CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) {
-  // "switch" is a control-flow statement.  Thus we stop processing the
-  // current block.    
-  CFGBlock* SwitchSuccessor = NULL;
-  
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-    SwitchSuccessor = Block;
-  }
-  else SwitchSuccessor = Succ;
-
-  // Save the current "switch" context.
-  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
-                            save_break(BreakTargetBlock),
-                            save_default(DefaultCaseBlock);
-
-  // Set the "default" case to be the block after the switch statement.
-  // If the switch statement contains a "default:", this value will
-  // be overwritten with the block for that code.
-  DefaultCaseBlock = SwitchSuccessor;
-  
-  // Create a new block that will contain the switch statement.
-  SwitchTerminatedBlock = createBlock(false);
-  
-  // Now process the switch body.  The code after the switch is the implicit
-  // successor.
-  Succ = SwitchSuccessor;
-  BreakTargetBlock = SwitchSuccessor;
-  
-  // When visiting the body, the case statements should automatically get
-  // linked up to the switch.  We also don't keep a pointer to the body,
-  // since all control-flow from the switch goes to case/default statements.
-  assert (Terminator->getBody() && "switch must contain a non-NULL body");
-  Block = NULL;
-  CFGBlock *BodyBlock = Visit(Terminator->getBody());
-  if (Block) {
-    if (!FinishBlock(BodyBlock))
-      return 0;
-  }
-
-  // If we have no "default:" case, the default transition is to the
-  // code following the switch body.
-  SwitchTerminatedBlock->addSuccessor(DefaultCaseBlock);
-  
-  // Add the terminator and condition in the switch block.
-  SwitchTerminatedBlock->setTerminator(Terminator);
-  assert (Terminator->getCond() && "switch condition must be non-NULL");
-  Block = SwitchTerminatedBlock;
-  
-  return addStmt(Terminator->getCond());
-}
-
-CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* Terminator) {
-  // CaseStmts are essentially labels, so they are the
-  // first statement in a block.      
-
-  if (Terminator->getSubStmt()) Visit(Terminator->getSubStmt());
-  CFGBlock* CaseBlock = Block;
-  if (!CaseBlock) CaseBlock = createBlock();  
-    
-  // Cases statements partition blocks, so this is the top of
-  // the basic block we were processing (the "case XXX:" is the label).
-  CaseBlock->setLabel(Terminator);
-  if (!FinishBlock(CaseBlock))
-    return 0;
-  
-  // Add this block to the list of successors for the block with the
-  // switch statement.
-  assert (SwitchTerminatedBlock);
-  SwitchTerminatedBlock->addSuccessor(CaseBlock);
-  
-  // We set Block to NULL to allow lazy creation of a new block (if necessary)
-  Block = NULL;
-  
-  // This block is now the implicit successor of other blocks.
-  Succ = CaseBlock;
-  
-  return CaseBlock;
-}
-  
-CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) {
-  if (Terminator->getSubStmt()) Visit(Terminator->getSubStmt());
-  DefaultCaseBlock = Block;
-  if (!DefaultCaseBlock) DefaultCaseBlock = createBlock();  
-  
-  // Default statements partition blocks, so this is the top of
-  // the basic block we were processing (the "default:" is the label).
-  DefaultCaseBlock->setLabel(Terminator);
-  if (!FinishBlock(DefaultCaseBlock))
-    return 0;
-
-  // Unlike case statements, we don't add the default block to the
-  // successors for the switch statement immediately.  This is done
-  // when we finish processing the switch statement.  This allows for
-  // the default case (including a fall-through to the code after the
-  // switch statement) to always be the last successor of a switch-terminated
-  // block.
-  
-  // We set Block to NULL to allow lazy creation of a new block (if necessary)
-  Block = NULL;
-  
-  // This block is now the implicit successor of other blocks.
-  Succ = DefaultCaseBlock;
-  
-  return DefaultCaseBlock;  
-}
-
-CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) {
-  // Lazily create the indirect-goto dispatch block if there isn't one
-  // already.
-  CFGBlock* IBlock = cfg->getIndirectGotoBlock();
-  
-  if (!IBlock) {
-    IBlock = createBlock(false);
-    cfg->setIndirectGotoBlock(IBlock);
-  }
-  
-  // IndirectGoto is a control-flow statement.  Thus we stop processing the
-  // current block and create a new one.
-  if (Block) {
-    if (!FinishBlock(Block))
-      return 0;
-  }
-  Block = createBlock(false);
-  Block->setTerminator(I);
-  Block->addSuccessor(IBlock);
-  return addStmt(I->getTarget());
-}
-
-
-} // end anonymous namespace
-
-/// createBlock - Constructs and adds a new CFGBlock to the CFG.  The
-///  block has no successors or predecessors.  If this is the first block
-///  created in the CFG, it is automatically set to be the Entry and Exit
-///  of the CFG.
-CFGBlock* CFG::createBlock() {
-  bool first_block = begin() == end();
-
-  // Create the block.
-  Blocks.push_front(CFGBlock(NumBlockIDs++));
-
-  // If this is the first block, set it as the Entry and Exit.
-  if (first_block) Entry = Exit = &front();
-
-  // Return the block.
-  return &front();
-}
-
-/// buildCFG - Constructs a CFG from an AST.  Ownership of the returned
-///  CFG is returned to the caller.
-CFG* CFG::buildCFG(Stmt* Statement) {
-  CFGBuilder Builder;
-  return Builder.buildCFG(Statement);
-}
-
-/// reverseStmts - Reverses the orders of statements within a CFGBlock.
-void CFGBlock::reverseStmts() { std::reverse(Stmts.begin(),Stmts.end()); }
-
-//===----------------------------------------------------------------------===//
-// CFG: Queries for BlkExprs.
-//===----------------------------------------------------------------------===//
-
-namespace {
-  typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
-}
-
-static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) {
-  if (!Terminator)
-    return;
-  
-  for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) {
-    if (!*I) continue;
-    
-    if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I))
-      if (B->isAssignmentOp()) Set.insert(B);
-    
-    FindSubExprAssignments(*I, Set);
-  }
-}
-
-static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) {
-  BlkExprMapTy* M = new BlkExprMapTy();
-  
-  // Look for assignments that are used as subexpressions.  These are the
-  // only assignments that we want to *possibly* register as a block-level
-  // expression.  Basically, if an assignment occurs both in a subexpression
-  // and at the block-level, it is a block-level expression.
-  llvm::SmallPtrSet<Expr*,50> SubExprAssignments;
-  
-  for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
-    for (CFGBlock::iterator BI=I->begin(), EI=I->end(); BI != EI; ++BI)
-      FindSubExprAssignments(*BI, SubExprAssignments);
-
-  for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
-    
-    // Iterate over the statements again on identify the Expr* and Stmt* at
-    // the block-level that are block-level expressions.
-
-    for (CFGBlock::iterator BI=I->begin(), EI=I->end(); BI != EI; ++BI)
-      if (Expr* Exp = dyn_cast<Expr>(*BI)) {
-        
-        if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
-          // Assignment expressions that are not nested within another
-          // expression are really "statements" whose value is never
-          // used by another expression.
-          if (B->isAssignmentOp() && !SubExprAssignments.count(Exp))
-            continue;
-        }
-        else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) {
-          // Special handling for statement expressions.  The last statement
-          // in the statement expression is also a block-level expr.
-          const CompoundStmt* C = Terminator->getSubStmt();
-          if (!C->body_empty()) {
-            unsigned x = M->size();
-            (*M)[C->body_back()] = x;
-          }
-        }
-
-        unsigned x = M->size();
-        (*M)[Exp] = x;
-      }
-    
-    // Look at terminators.  The condition is a block-level expression.
-    
-    Stmt* S = I->getTerminatorCondition();
-    
-    if (S && M->find(S) == M->end()) {
-        unsigned x = M->size();
-        (*M)[S] = x;
-    }
-  }
-    
-  return M;
-}
-
-CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) {
-  assert(S != NULL);
-  if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); }
-  
-  BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap);
-  BlkExprMapTy::iterator I = M->find(S);
-  
-  if (I == M->end()) return CFG::BlkExprNumTy();
-  else return CFG::BlkExprNumTy(I->second);
-}
-
-unsigned CFG::getNumBlkExprs() {
-  if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
-    return M->size();
-  else {
-    // We assume callers interested in the number of BlkExprs will want
-    // the map constructed if it doesn't already exist.
-    BlkExprMap = (void*) PopulateBlkExprMap(*this);
-    return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size();
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// Cleanup: CFG dstor.
-//===----------------------------------------------------------------------===//
-
-CFG::~CFG() {
-  delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
-}
-  
-//===----------------------------------------------------------------------===//
-// CFG pretty printing
-//===----------------------------------------------------------------------===//
-
-namespace {
-
-class VISIBILITY_HIDDEN StmtPrinterHelper : public PrinterHelper  {
-                          
-  typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
-  StmtMapTy StmtMap;
-  signed CurrentBlock;
-  unsigned CurrentStmt;
-  const LangOptions &LangOpts;
-public:
-
-  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
-    : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) {
-    for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
-      unsigned j = 1;
-      for (CFGBlock::const_iterator BI = I->begin(), BEnd = I->end() ;
-           BI != BEnd; ++BI, ++j )
-        StmtMap[*BI] = std::make_pair(I->getBlockID(),j);
-      }
-  }
-            
-  virtual ~StmtPrinterHelper() {}
-  
-  const LangOptions &getLangOpts() const { return LangOpts; }
-  void setBlockID(signed i) { CurrentBlock = i; }
-  void setStmtID(unsigned i) { CurrentStmt = i; }
-  
-  virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) {
-    
-    StmtMapTy::iterator I = StmtMap.find(Terminator);
-
-    if (I == StmtMap.end())
-      return false;
-    
-    if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 
-                          && I->second.second == CurrentStmt)
-      return false;
-      
-      OS << "[B" << I->second.first << "." << I->second.second << "]";
-    return true;
-  }
-};
-} // end anonymous namespace
-
-
-namespace {
-class VISIBILITY_HIDDEN CFGBlockTerminatorPrint
-  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
-  
-  llvm::raw_ostream& OS;
-  StmtPrinterHelper* Helper;
-  PrintingPolicy Policy;
-
-public:
-  CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper,
-                          const PrintingPolicy &Policy)
-    : OS(os), Helper(helper), Policy(Policy) {}
-  
-  void VisitIfStmt(IfStmt* I) {
-    OS << "if ";
-    I->getCond()->printPretty(OS,Helper,Policy);
-  }
-  
-  // Default case.
-  void VisitStmt(Stmt* Terminator) { Terminator->printPretty(OS, Helper, Policy); }
-  
-  void VisitForStmt(ForStmt* F) {
-    OS << "for (" ;
-    if (F->getInit()) OS << "...";
-    OS << "; ";
-    if (Stmt* C = F->getCond()) C->printPretty(OS, Helper, Policy);
-    OS << "; ";
-    if (F->getInc()) OS << "...";
-    OS << ")";
-  }
-  
-  void VisitWhileStmt(WhileStmt* W) {
-    OS << "while " ;
-    if (Stmt* C = W->getCond()) C->printPretty(OS, Helper, Policy);
-  }
-  
-  void VisitDoStmt(DoStmt* D) {
-    OS << "do ... while ";
-    if (Stmt* C = D->getCond()) C->printPretty(OS, Helper, Policy);
-  }
-  
-  void VisitSwitchStmt(SwitchStmt* Terminator) {
-    OS << "switch ";
-    Terminator->getCond()->printPretty(OS, Helper, Policy);
-  }
-  
-  void VisitConditionalOperator(ConditionalOperator* C) {
-    C->getCond()->printPretty(OS, Helper, Policy);
-    OS << " ? ... : ...";  
-  }
-  
-  void VisitChooseExpr(ChooseExpr* C) {
-    OS << "__builtin_choose_expr( ";
-    C->getCond()->printPretty(OS, Helper, Policy);
-    OS << " )";
-  }
-  
-  void VisitIndirectGotoStmt(IndirectGotoStmt* I) {
-    OS << "goto *";
-    I->getTarget()->printPretty(OS, Helper, Policy);
-  }
-  
-  void VisitBinaryOperator(BinaryOperator* B) {
-    if (!B->isLogicalOp()) {
-      VisitExpr(B);
-      return;
-    }
-    
-    B->getLHS()->printPretty(OS, Helper, Policy);
-    
-    switch (B->getOpcode()) {
-      case BinaryOperator::LOr:
-        OS << " || ...";
-        return;
-      case BinaryOperator::LAnd:
-        OS << " && ...";
-        return;
-      default:
-        assert(false && "Invalid logical operator.");
-    }  
-  }
-  
-  void VisitExpr(Expr* E) {
-    E->printPretty(OS, Helper, Policy);
-  }                                                       
-};
-} // end anonymous namespace
-
-  
-static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper,
-                       Stmt* Terminator) {
-  if (Helper) {
-    // special printing for statement-expressions.
-    if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) {
-      CompoundStmt* Sub = SE->getSubStmt();
-      
-      if (Sub->child_begin() != Sub->child_end()) {
-        OS << "({ ... ; ";
-        Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
-        OS << " })\n";
-        return;
-      }
-    }
-    
-    // special printing for comma expressions.
-    if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) {
-      if (B->getOpcode() == BinaryOperator::Comma) {
-        OS << "... , ";
-        Helper->handledStmt(B->getRHS(),OS);
-        OS << '\n';
-        return;
-      }          
-    }  
-  }
-  
-  Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
-  
-  // Expressions need a newline.
-  if (isa<Expr>(Terminator)) OS << '\n';
-}
-  
-static void print_block(llvm::raw_ostream& OS, const CFG* cfg,
-                        const CFGBlock& B,
-                        StmtPrinterHelper* Helper, bool print_edges) {
- 
-  if (Helper) Helper->setBlockID(B.getBlockID());
-  
-  // Print the header.
-  OS << "\n [ B" << B.getBlockID();  
-    
-  if (&B == &cfg->getEntry())
-    OS << " (ENTRY) ]\n";
-  else if (&B == &cfg->getExit())
-    OS << " (EXIT) ]\n";
-  else if (&B == cfg->getIndirectGotoBlock())
-    OS << " (INDIRECT GOTO DISPATCH) ]\n";
-  else
-    OS << " ]\n";
- 
-  // Print the label of this block.
-  if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) {
-
-    if (print_edges)
-      OS << "    ";
-  
-    if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator))
-      OS << L->getName();
-    else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) {
-      OS << "case ";
-      C->getLHS()->printPretty(OS, Helper,
-                               PrintingPolicy(Helper->getLangOpts()));
-      if (C->getRHS()) {
-        OS << " ... ";
-        C->getRHS()->printPretty(OS, Helper,
-                                 PrintingPolicy(Helper->getLangOpts()));
-      }
-    }  
-    else if (isa<DefaultStmt>(Terminator))
-      OS << "default";
-    else
-      assert(false && "Invalid label statement in CFGBlock.");
- 
-    OS << ":\n";
-  }
- 
-  // Iterate through the statements in the block and print them.
-  unsigned j = 1;
-  
-  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
-       I != E ; ++I, ++j ) {
-       
-    // Print the statement # in the basic block and the statement itself.
-    if (print_edges)
-      OS << "    ";
-      
-    OS << llvm::format("%3d", j) << ": ";
-    
-    if (Helper)
-      Helper->setStmtID(j);
-     
-    print_stmt(OS,Helper,*I);
-  }
- 
-  // Print the terminator of this block.
-  if (B.getTerminator()) {
-    if (print_edges)
-      OS << "    ";
-      
-    OS << "  T: ";
-    
-    if (Helper) Helper->setBlockID(-1);
-    
-    CFGBlockTerminatorPrint TPrinter(OS, Helper,
-                                     PrintingPolicy(Helper->getLangOpts()));
-    TPrinter.Visit(const_cast<Stmt*>(B.getTerminator()));
-    OS << '\n';
-  }
- 
-  if (print_edges) {
-    // Print the predecessors of this block.
-    OS << "    Predecessors (" << B.pred_size() << "):";
-    unsigned i = 0;
-
-    for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
-         I != E; ++I, ++i) {
-                  
-      if (i == 8 || (i-8) == 0)
-        OS << "\n     ";
-      
-      OS << " B" << (*I)->getBlockID();
-    }
-    
-    OS << '\n';
- 
-    // Print the successors of this block.
-    OS << "    Successors (" << B.succ_size() << "):";
-    i = 0;
-
-    for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
-         I != E; ++I, ++i) {
-         
-      if (i == 8 || (i-8) % 10 == 0)
-        OS << "\n    ";
-
-      OS << " B" << (*I)->getBlockID();
-    }
-    
-    OS << '\n';
-  }
-}                   
-
-
-/// dump - A simple pretty printer of a CFG that outputs to stderr.
-void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); }
-
-/// print - A simple pretty printer of a CFG that outputs to an ostream.
-void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const {
-  StmtPrinterHelper Helper(this, LO);
-  
-  // Print the entry block.
-  print_block(OS, this, getEntry(), &Helper, true);
-                    
-  // Iterate through the CFGBlocks and print them one by one.
-  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
-    // Skip the entry block, because we already printed it.
-    if (&(*I) == &getEntry() || &(*I) == &getExit())
-      continue;
-      
-    print_block(OS, this, *I, &Helper, true);
-  }
-  
-  // Print the exit block.
-  print_block(OS, this, getExit(), &Helper, true);
-  OS.flush();
-}  
-
-/// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
-void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const {
-  print(llvm::errs(), cfg, LO);
-}
-
-/// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
-///   Generally this will only be called from CFG::print.
-void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg,
-                     const LangOptions &LO) const {
-  StmtPrinterHelper Helper(cfg, LO);
-  print_block(OS, cfg, *this, &Helper, true);
-}
-
-/// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
-void CFGBlock::printTerminator(llvm::raw_ostream &OS,
-                               const LangOptions &LO) const {  
-  CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
-  TPrinter.Visit(const_cast<Stmt*>(getTerminator()));
-}
-
-Stmt* CFGBlock::getTerminatorCondition() {
-  
-  if (!Terminator)
-    return NULL;
-  
-  Expr* E = NULL;
-  
-  switch (Terminator->getStmtClass()) {
-    default:
-      break;
-      
-    case Stmt::ForStmtClass:
-      E = cast<ForStmt>(Terminator)->getCond();
-      break;
-      
-    case Stmt::WhileStmtClass:
-      E = cast<WhileStmt>(Terminator)->getCond();
-      break;
-      
-    case Stmt::DoStmtClass:
-      E = cast<DoStmt>(Terminator)->getCond();
-      break;
-      
-    case Stmt::IfStmtClass:
-      E = cast<IfStmt>(Terminator)->getCond();
-      break;
-      
-    case Stmt::ChooseExprClass:
-      E = cast<ChooseExpr>(Terminator)->getCond();
-      break;
-      
-    case Stmt::IndirectGotoStmtClass:
-      E = cast<IndirectGotoStmt>(Terminator)->getTarget();
-      break;
-      
-    case Stmt::SwitchStmtClass:
-      E = cast<SwitchStmt>(Terminator)->getCond();
-      break;
-      
-    case Stmt::ConditionalOperatorClass:
-      E = cast<ConditionalOperator>(Terminator)->getCond();
-      break;
-      
-    case Stmt::BinaryOperatorClass: // '&&' and '||'
-      E = cast<BinaryOperator>(Terminator)->getLHS();
-      break;
-      
-    case Stmt::ObjCForCollectionStmtClass:
-      return Terminator;      
-  }
-  
-  return E ? E->IgnoreParens() : NULL;
-}
-
-bool CFGBlock::hasBinaryBranchTerminator() const {
-  
-  if (!Terminator)
-    return false;
-  
-  Expr* E = NULL;
-  
-  switch (Terminator->getStmtClass()) {
-    default:
-      return false;
-      
-    case Stmt::ForStmtClass:      
-    case Stmt::WhileStmtClass:
-    case Stmt::DoStmtClass:
-    case Stmt::IfStmtClass:
-    case Stmt::ChooseExprClass:
-    case Stmt::ConditionalOperatorClass:
-    case Stmt::BinaryOperatorClass:
-      return true;      
-  }
-  
-  return E ? E->IgnoreParens() : NULL;
-}
-
-
-//===----------------------------------------------------------------------===//
-// CFG Graphviz Visualization
-//===----------------------------------------------------------------------===//
-
-
-#ifndef NDEBUG
-static StmtPrinterHelper* GraphHelper;  
-#endif
-
-void CFG::viewCFG(const LangOptions &LO) const {
-#ifndef NDEBUG
-  StmtPrinterHelper H(this, LO);
-  GraphHelper = &H;
-  llvm::ViewGraph(this,"CFG");
-  GraphHelper = NULL;
-#endif
-}
-
-namespace llvm {
-template<>
-struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
-  static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph,
-                                  bool ShortNames) {
-
-#ifndef NDEBUG
-    std::string OutSStr;
-    llvm::raw_string_ostream Out(OutSStr);
-    print_block(Out,Graph, *Node, GraphHelper, false);
-    std::string& OutStr = Out.str();
-
-    if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
-
-    // Process string output to make it nicer...
-    for (unsigned i = 0; i != OutStr.length(); ++i)
-      if (OutStr[i] == '\n') {                            // Left justify
-        OutStr[i] = '\\';
-        OutStr.insert(OutStr.begin()+i+1, 'l');
-      }
-      
-    return OutStr;
-#else
-    return "";
-#endif
-  }
-};
-} // end namespace llvm