Add dump() routines to help debug debug info :)

[oota-llvm.git] / lib / VMCore / BasicBlock.cpp

diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index f9bead74d25d9ab05680d08b0d43b1a9ddf48403..a76f659233d4270f4ed29e1db56a292f1fa8c56c 100644 (file)
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -15,6 +15,7 @@
 #include "llvm/Constants.h"
 #include "llvm/Instructions.h"
 #include "llvm/Type.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Support/LeakDetector.h"
 #include "llvm/Support/Compiler.h"
@@ -35,6 +36,10 @@ namespace {
   /// DummyInst - An instance of this class is used to mark the end of the
   /// instruction list.  This is not a real instruction.
   struct VISIBILITY_HIDDEN DummyInst : public Instruction {
+    // allocate space for exactly zero operands
+    void *operator new(size_t s) {
+      return User::operator new(s, 0);
+    }
     DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) {
       // This should not be garbage monitored.
       LeakDetector::removeGarbageObject(this);
@@ -70,8 +75,8 @@ template class SymbolTableListTraits<Instruction, BasicBlock>;
 
 
 BasicBlock::BasicBlock(const std::string &Name, Function *NewParent,
-                       BasicBlock *InsertBefore, BasicBlock *Dest)
-  : User(Type::LabelTy, Value::BasicBlockVal, &unwindDest, 0), Parent(0) {
+                       BasicBlock *InsertBefore)
+  : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) {
 
   // Make sure that we get added to a function
   LeakDetector::addGarbageObject(this);
@@ -85,8 +90,6 @@ BasicBlock::BasicBlock(const std::string &Name, Function *NewParent,
   }
   
   setName(Name);
-  unwindDest.init(NULL, this);
-  setUnwindDest(Dest);
 }
 
 
@@ -115,19 +118,6 @@ void BasicBlock::eraseFromParent() {
   getParent()->getBasicBlockList().erase(this);
 }
 
-const BasicBlock *BasicBlock::getUnwindDest() const {
-  return cast_or_null<const BasicBlock>(unwindDest.get());
-}
-
-BasicBlock *BasicBlock::getUnwindDest() {
-  return cast_or_null<BasicBlock>(unwindDest.get());
-}
-
-void BasicBlock::setUnwindDest(BasicBlock *dest) {
-  NumOperands = unwindDest ? 1 : 0;
-  unwindDest.set(dest);
-}
-
 /// moveBefore - Unlink this basic block from its current function and
 /// insert it into the function that MovePos lives in, right before MovePos.
 void BasicBlock::moveBefore(BasicBlock *MovePos) {
@@ -154,19 +144,17 @@ const TerminatorInst *BasicBlock::getTerminator() const {
   return dyn_cast<TerminatorInst>(&InstList.back());
 }
 
-Instruction* BasicBlock::getFirstNonPHI()
-{
-    BasicBlock::iterator i = begin();
-    // All valid basic blocks should have a terminator,
-    // which is not a PHINode. If we have invalid basic
-    // block we'll get assert when dereferencing past-the-end
-    // iterator.
-    while (isa<PHINode>(i)) ++i;
-    return &*i;
+Instruction* BasicBlock::getFirstNonPHI() {
+  BasicBlock::iterator i = begin();
+  // All valid basic blocks should have a terminator,
+  // which is not a PHINode. If we have an invalid basic
+  // block we'll get an assertion failure when dereferencing
+  // a past-the-end iterator.
+  while (isa<PHINode>(i)) ++i;
+  return &*i;
 }
 
 void BasicBlock::dropAllReferences() {
-  setUnwindDest(NULL);
   for(iterator I = begin(), E = end(); I != E; ++I)
     I->dropAllReferences();
 }
@@ -181,6 +169,25 @@ BasicBlock *BasicBlock::getSinglePredecessor() {
   return (PI == E) ? ThePred : 0 /*multiple preds*/;
 }
 
+/// 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 *BasicBlock::getUniquePredecessor() {
+  pred_iterator PI = pred_begin(this), E = pred_end(this);
+  if (PI == E) return 0; // No preds.
+  BasicBlock *PredBB = *PI;
+  ++PI;
+  for (;PI != E; ++PI) {
+    if (*PI != PredBB)
+      return 0;
+    // The same predecessor appears multiple times in the predecessor list.
+    // This is OK.
+  }
+  return PredBB;
+}
+
 /// 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
@@ -193,9 +200,6 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
           find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) &&
          "removePredecessor: BB is not a predecessor!");
 
-  if (Pred == getUnwindDest())
-    setUnwindDest(NULL);
-
   if (InstList.empty()) return;
   PHINode *APN = dyn_cast<PHINode>(&front());
   if (!APN) return;   // Quick exit.
@@ -276,14 +280,16 @@ BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) {
   assert(I != InstList.end() &&
          "Trying to get me to create degenerate basic block!");
 
-  BasicBlock *New = new BasicBlock(BBName, getParent(), getNext());
+  BasicBlock *InsertBefore = next(Function::iterator(this))
+                               .getNodePtrUnchecked();
+  BasicBlock *New = BasicBlock::Create(BBName, getParent(), InsertBefore);
 
   // Move all of the specified instructions from the original basic block into
   // the new basic block.
   New->getInstList().splice(New->end(), this->getInstList(), I, end());
 
   // Add a branch instruction to the newly formed basic block.
-  new BranchInst(New, this);
+  BranchInst::Create(New, this);
 
   // Now we must loop through all of the successors of the New block (which
   // _were_ the successors of the 'this' block), and update any PHI nodes in