Rename VMCore directory to IR.

Aside from moving the actual files, this patch only updates the build
system and the source file comments under lib/... that are relevant.

I'll be updating other docs and other files in smaller subsequnet
commits.

While I've tried to test this, but it is entirely possible that there
will still be some build system fallout.

Also, note that I've not changed the library name itself: libLLVMCore.a
is still the library name. I'd be interested in others' opinions about
whether we should rename this as well (I think we should, just not sure
what it might break)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171359 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 371 insertions, 0 deletions

diff --git a/lib/IR/BasicBlock.cpp b/lib/IR/BasicBlock.cpp
new file mode 100644
index 0000000000..db20b08d8e
--- /dev/null
+++ b/lib/IR/BasicBlock.cpp
@@ -0,0 +1,371 @@
+//===-- BasicBlock.cpp - Implement BasicBlock related methods -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the BasicBlock class for the IR library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/BasicBlock.h"
+#include "SymbolTableListTraitsImpl.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Constants.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/LeakDetector.h"
+#include "llvm/Type.h"
+#include <algorithm>
+using namespace llvm;
+
+ValueSymbolTable *BasicBlock::getValueSymbolTable() {
+  if (Function *F = getParent())
+    return &F->getValueSymbolTable();
+  return 0;
+}
+
+LLVMContext &BasicBlock::getContext() const {
+  return getType()->getContext();
+}
+
+// Explicit instantiation of SymbolTableListTraits since some of the methods
+// are not in the public header file...
+template class llvm::SymbolTableListTraits<Instruction, BasicBlock>;
+
+
+BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
+                       BasicBlock *InsertBefore)
+  : Value(Type::getLabelTy(C), Value::BasicBlockVal), Parent(0) {
+
+  // Make sure that we get added to a function
+  LeakDetector::addGarbageObject(this);
+
+  if (InsertBefore) {
+    assert(NewParent &&
+           "Cannot insert block before another block with no function!");
+    NewParent->getBasicBlockList().insert(InsertBefore, this);
+  } else if (NewParent) {
+    NewParent->getBasicBlockList().push_back(this);
+  }
+
+  setName(Name);
+}
+
+
+BasicBlock::~BasicBlock() {
+  // If the address of the block is taken and it is being deleted (e.g. because
+  // it is dead), this means that there is either a dangling constant expr
+  // hanging off the block, or an undefined use of the block (source code
+  // expecting the address of a label to keep the block alive even though there
+  // is no indirect branch).  Handle these cases by zapping the BlockAddress
+  // nodes.  There are no other possible uses at this point.
+  if (hasAddressTaken()) {
+    assert(!use_empty() && "There should be at least one blockaddress!");
+    Constant *Replacement =
+      ConstantInt::get(llvm::Type::getInt32Ty(getContext()), 1);
+    while (!use_empty()) {
+      BlockAddress *BA = cast<BlockAddress>(use_back());
+      BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement,
+                                                       BA->getType()));
+      BA->destroyConstant();
+    }
+  }
+
+  assert(getParent() == 0 && "BasicBlock still linked into the program!");
+  dropAllReferences();
+  InstList.clear();
+}
+
+void BasicBlock::setParent(Function *parent) {
+  if (getParent())
+    LeakDetector::addGarbageObject(this);
+
+  // Set Parent=parent, updating instruction symtab entries as appropriate.
+  InstList.setSymTabObject(&Parent, parent);
+
+  if (getParent())
+    LeakDetector::removeGarbageObject(this);
+}
+
+void BasicBlock::removeFromParent() {
+  getParent()->getBasicBlockList().remove(this);
+}
+
+void BasicBlock::eraseFromParent() {
+  getParent()->getBasicBlockList().erase(this);
+}
+
+/// 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) {
+  MovePos->getParent()->getBasicBlockList().splice(MovePos,
+                       getParent()->getBasicBlockList(), this);
+}
+
+/// moveAfter - Unlink this basic block from its current function and
+/// insert it into the function that MovePos lives in, right after MovePos.
+void BasicBlock::moveAfter(BasicBlock *MovePos) {
+  Function::iterator I = MovePos;
+  MovePos->getParent()->getBasicBlockList().splice(++I,
+                                       getParent()->getBasicBlockList(), this);
+}
+
+
+TerminatorInst *BasicBlock::getTerminator() {
+  if (InstList.empty()) return 0;
+  return dyn_cast<TerminatorInst>(&InstList.back());
+}
+
+const TerminatorInst *BasicBlock::getTerminator() const {
+  if (InstList.empty()) return 0;
+  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 an invalid basic
+  // block we'll get an assertion failure when dereferencing
+  // a past-the-end iterator.
+  while (isa<PHINode>(i)) ++i;
+  return &*i;
+}
+
+Instruction* BasicBlock::getFirstNonPHIOrDbg() {
+  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) || isa<DbgInfoIntrinsic>(i)) ++i;
+  return &*i;
+}
+
+Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() {
+  // 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.
+  BasicBlock::iterator i = begin();
+  for (;; ++i) {
+    if (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i))
+      continue;
+
+    const IntrinsicInst *II = dyn_cast<IntrinsicInst>(i);
+    if (!II)
+      break;
+    if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
+        II->getIntrinsicID() != Intrinsic::lifetime_end)
+      break;
+  }
+  return &*i;
+}
+
+BasicBlock::iterator BasicBlock::getFirstInsertionPt() {
+  iterator InsertPt = getFirstNonPHI();
+  if (isa<LandingPadInst>(InsertPt)) ++InsertPt;
+  return InsertPt;
+}
+
+void BasicBlock::dropAllReferences() {
+  for(iterator I = begin(), E = end(); I != E; ++I)
+    I->dropAllReferences();
+}
+
+/// getSinglePredecessor - If this basic block has a single predecessor block,
+/// return the block, otherwise return a null pointer.
+BasicBlock *BasicBlock::getSinglePredecessor() {
+  pred_iterator PI = pred_begin(this), E = pred_end(this);
+  if (PI == E) return 0;         // No preds.
+  BasicBlock *ThePred = *PI;
+  ++PI;
+  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
+/// update the PHI nodes that reside in the block.  Note that this should be
+/// called while the predecessor still refers to this block.
+///
+void BasicBlock::removePredecessor(BasicBlock *Pred,
+                                   bool DontDeleteUselessPHIs) {
+  assert((hasNUsesOrMore(16)||// Reduce cost of this assertion for complex CFGs.
+          find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) &&
+         "removePredecessor: BB is not a predecessor!");
+
+  if (InstList.empty()) return;
+  PHINode *APN = dyn_cast<PHINode>(&front());
+  if (!APN) return;   // Quick exit.
+
+  // If there are exactly two predecessors, then we want to nuke the PHI nodes
+  // altogether.  However, we cannot do this, if this in this case:
+  //
+  //  Loop:
+  //    %x = phi [X, Loop]
+  //    %x2 = add %x, 1         ;; This would become %x2 = add %x2, 1
+  //    br Loop                 ;; %x2 does not dominate all uses
+  //
+  // This is because the PHI node input is actually taken from the predecessor
+  // basic block.  The only case this can happen is with a self loop, so we
+  // check for this case explicitly now.
+  //
+  unsigned max_idx = APN->getNumIncomingValues();
+  assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!");
+  if (max_idx == 2) {
+    BasicBlock *Other = APN->getIncomingBlock(APN->getIncomingBlock(0) == Pred);
+
+    // Disable PHI elimination!
+    if (this == Other) max_idx = 3;
+  }
+
+  // <= Two predecessors BEFORE I remove one?
+  if (max_idx <= 2 && !DontDeleteUselessPHIs) {
+    // Yup, loop through and nuke the PHI nodes
+    while (PHINode *PN = dyn_cast<PHINode>(&front())) {
+      // Remove the predecessor first.
+      PN->removeIncomingValue(Pred, !DontDeleteUselessPHIs);
+
+      // If the PHI _HAD_ two uses, replace PHI node with its now *single* value
+      if (max_idx == 2) {
+        if (PN->getIncomingValue(0) != PN)
+          PN->replaceAllUsesWith(PN->getIncomingValue(0));
+        else
+          // We are left with an infinite loop with no entries: kill the PHI.
+          PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
+        getInstList().pop_front();    // Remove the PHI node
+      }
+
+      // If the PHI node already only had one entry, it got deleted by
+      // removeIncomingValue.
+    }
+  } else {
+    // Okay, now we know that we need to remove predecessor #pred_idx from all
+    // PHI nodes.  Iterate over each PHI node fixing them up
+    PHINode *PN;
+    for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ) {
+      ++II;
+      PN->removeIncomingValue(Pred, false);
+      // If all incoming values to the Phi are the same, we can replace the Phi
+      // with that value.
+      Value* PNV = 0;
+      if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue()))
+        if (PNV != PN) {
+          PN->replaceAllUsesWith(PNV);
+          PN->eraseFromParent();
+        }
+    }
+  }
+}
+
+
+/// 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 new BB, and the rest of the instructions in the BB are moved to the new
+/// BB, including the old terminator.  This invalidates the 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 *BasicBlock::splitBasicBlock(iterator I, const Twine &BBName) {
+  assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!");
+  assert(I != InstList.end() &&
+         "Trying to get me to create degenerate basic block!");
+
+  BasicBlock *InsertBefore = llvm::next(Function::iterator(this))
+                               .getNodePtrUnchecked();
+  BasicBlock *New = BasicBlock::Create(getContext(), 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.
+  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
+  // successors.  If there were PHI nodes in the successors, then they need to
+  // know that incoming branches will be from New, not from Old.
+  //
+  for (succ_iterator I = succ_begin(New), E = succ_end(New); I != E; ++I) {
+    // Loop over any phi nodes in the basic block, updating the BB field of
+    // incoming values...
+    BasicBlock *Successor = *I;
+    PHINode *PN;
+    for (BasicBlock::iterator II = Successor->begin();
+         (PN = dyn_cast<PHINode>(II)); ++II) {
+      int IDX = PN->getBasicBlockIndex(this);
+      while (IDX != -1) {
+        PN->setIncomingBlock((unsigned)IDX, New);
+        IDX = PN->getBasicBlockIndex(this);
+      }
+    }
+  }
+  return New;
+}
+
+void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) {
+  TerminatorInst *TI = getTerminator();
+  if (!TI)
+    // Cope with being called on a BasicBlock that doesn't have a terminator
+    // yet. Clang's CodeGenFunction::EmitReturnBlock() likes to do this.
+    return;
+  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
+    BasicBlock *Succ = TI->getSuccessor(i);
+    // N.B. Succ might not be a complete BasicBlock, so don't assume
+    // that it ends with a non-phi instruction.
+    for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) {
+      PHINode *PN = dyn_cast<PHINode>(II);
+      if (!PN)
+        break;
+      int i;
+      while ((i = PN->getBasicBlockIndex(this)) >= 0)
+        PN->setIncomingBlock(i, New);
+    }
+  }
+}
+
+/// isLandingPad - Return true if this basic block is a landing pad. I.e., it's
+/// the destination of the 'unwind' edge of an invoke instruction.
+bool BasicBlock::isLandingPad() const {
+  return isa<LandingPadInst>(getFirstNonPHI());
+}
+
+/// getLandingPadInst() - Return the landingpad instruction associated with
+/// the landing pad.
+LandingPadInst *BasicBlock::getLandingPadInst() {
+  return dyn_cast<LandingPadInst>(getFirstNonPHI());
+}
+const LandingPadInst *BasicBlock::getLandingPadInst() const {
+  return dyn_cast<LandingPadInst>(getFirstNonPHI());
+}