Import LLVM, at r72732.vendor/llvm/llvm-r72732

1 files changed, 340 insertions, 0 deletions

diff --git a/lib/Analysis/LoopPass.cpp b/lib/Analysis/LoopPass.cpp
new file mode 100644
index 000000000000..08c25f4ceae4
--- /dev/null
+++ b/lib/Analysis/LoopPass.cpp
@@ -0,0 +1,340 @@
+//===- LoopPass.cpp - Loop Pass and Loop Pass Manager ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements LoopPass and LPPassManager. All loop optimization
+// and transformation passes are derived from LoopPass. LPPassManager is
+// responsible for managing LoopPasses.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LoopPass.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// LPPassManager
+//
+
+char LPPassManager::ID = 0;
+/// LPPassManager manages FPPassManagers and CalLGraphSCCPasses.
+
+LPPassManager::LPPassManager(int Depth) 
+  : FunctionPass(&ID), PMDataManager(Depth) { 
+  skipThisLoop = false;
+  redoThisLoop = false;
+  LI = NULL;
+  CurrentLoop = NULL;
+}
+
+/// Delete loop from the loop queue and loop hierarchy (LoopInfo). 
+void LPPassManager::deleteLoopFromQueue(Loop *L) {
+
+  if (Loop *ParentLoop = L->getParentLoop()) { // Not a top-level loop.
+    // Reparent all of the blocks in this loop.  Since BBLoop had a parent,
+    // they are now all in it.
+    for (Loop::block_iterator I = L->block_begin(), E = L->block_end(); 
+         I != E; ++I)
+      if (LI->getLoopFor(*I) == L)    // Don't change blocks in subloops.
+        LI->changeLoopFor(*I, ParentLoop);
+    
+    // Remove the loop from its parent loop.
+    for (Loop::iterator I = ParentLoop->begin(), E = ParentLoop->end();;
+         ++I) {
+      assert(I != E && "Couldn't find loop");
+      if (*I == L) {
+        ParentLoop->removeChildLoop(I);
+        break;
+      }
+    }
+    
+    // Move all subloops into the parent loop.
+    while (!L->empty())
+      ParentLoop->addChildLoop(L->removeChildLoop(L->end()-1));
+  } else {
+    // Reparent all of the blocks in this loop.  Since BBLoop had no parent,
+    // they no longer in a loop at all.
+    
+    for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
+      // Don't change blocks in subloops.
+      if (LI->getLoopFor(L->getBlocks()[i]) == L) {
+        LI->removeBlock(L->getBlocks()[i]);
+        --i;
+      }
+    }
+
+    // Remove the loop from the top-level LoopInfo object.
+    for (LoopInfo::iterator I = LI->begin(), E = LI->end();; ++I) {
+      assert(I != E && "Couldn't find loop");
+      if (*I == L) {
+        LI->removeLoop(I);
+        break;
+      }
+    }
+
+    // Move all of the subloops to the top-level.
+    while (!L->empty())
+      LI->addTopLevelLoop(L->removeChildLoop(L->end()-1));
+  }
+
+  delete L;
+
+  // If L is current loop then skip rest of the passes and let
+  // runOnFunction remove L from LQ. Otherwise, remove L from LQ now
+  // and continue applying other passes on CurrentLoop.
+  if (CurrentLoop == L) {
+    skipThisLoop = true;
+    return;
+  }
+
+  for (std::deque<Loop *>::iterator I = LQ.begin(),
+         E = LQ.end(); I != E; ++I) {
+    if (*I == L) {
+      LQ.erase(I);
+      break;
+    }
+  }
+}
+
+// Inset loop into loop nest (LoopInfo) and loop queue (LQ).
+void LPPassManager::insertLoop(Loop *L, Loop *ParentLoop) {
+
+  assert (CurrentLoop != L && "Cannot insert CurrentLoop");
+
+  // Insert into loop nest
+  if (ParentLoop)
+    ParentLoop->addChildLoop(L);
+  else
+    LI->addTopLevelLoop(L);
+
+  // Insert L into loop queue
+  if (L == CurrentLoop) 
+    redoLoop(L);
+  else if (!ParentLoop)
+    // This is top level loop. 
+    LQ.push_front(L);
+  else {
+    // Insert L after ParentLoop
+    for (std::deque<Loop *>::iterator I = LQ.begin(),
+           E = LQ.end(); I != E; ++I) {
+      if (*I == ParentLoop) {
+        // deque does not support insert after.
+        ++I;
+        LQ.insert(I, 1, L);
+        break;
+      }
+    }
+  }
+}
+
+// Reoptimize this loop. LPPassManager will re-insert this loop into the
+// queue. This allows LoopPass to change loop nest for the loop. This
+// utility may send LPPassManager into infinite loops so use caution.
+void LPPassManager::redoLoop(Loop *L) {
+  assert (CurrentLoop == L && "Can redo only CurrentLoop");
+  redoThisLoop = true;
+}
+
+/// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
+/// all loop passes.
+void LPPassManager::cloneBasicBlockSimpleAnalysis(BasicBlock *From, 
+                                                  BasicBlock *To, Loop *L) {
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {  
+    Pass *P = getContainedPass(Index);
+    LoopPass *LP = dynamic_cast<LoopPass *>(P);
+    LP->cloneBasicBlockAnalysis(From, To, L);
+  }
+}
+
+/// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes.
+void LPPassManager::deleteSimpleAnalysisValue(Value *V, Loop *L) {
+  if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
+    for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE; 
+         ++BI) {
+      Instruction &I = *BI;
+      deleteSimpleAnalysisValue(&I, L);
+    }
+  }
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {  
+    Pass *P = getContainedPass(Index);
+    LoopPass *LP = dynamic_cast<LoopPass *>(P);
+    LP->deleteAnalysisValue(V, L);
+  }
+}
+
+
+// Recurse through all subloops and all loops  into LQ.
+static void addLoopIntoQueue(Loop *L, std::deque<Loop *> &LQ) {
+  LQ.push_back(L);
+  for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
+    addLoopIntoQueue(*I, LQ);
+}
+
+/// Pass Manager itself does not invalidate any analysis info.
+void LPPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
+  // LPPassManager needs LoopInfo. In the long term LoopInfo class will 
+  // become part of LPPassManager.
+  Info.addRequired<LoopInfo>();
+  Info.setPreservesAll();
+}
+
+/// run - Execute all of the passes scheduled for execution.  Keep track of
+/// whether any of the passes modifies the function, and if so, return true.
+bool LPPassManager::runOnFunction(Function &F) {
+  LI = &getAnalysis<LoopInfo>();
+  bool Changed = false;
+
+  // Collect inherited analysis from Module level pass manager.
+  populateInheritedAnalysis(TPM->activeStack);
+
+  // Populate Loop Queue
+  for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
+    addLoopIntoQueue(*I, LQ);
+
+  // Initialization
+  for (std::deque<Loop *>::const_iterator I = LQ.begin(), E = LQ.end();
+       I != E; ++I) {
+    Loop *L = *I;
+    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {  
+      Pass *P = getContainedPass(Index);
+      LoopPass *LP = dynamic_cast<LoopPass *>(P);
+      if (LP)
+        Changed |= LP->doInitialization(L, *this);
+    }
+  }
+
+  // Walk Loops
+  while (!LQ.empty()) {
+      
+    CurrentLoop  = LQ.back();
+    skipThisLoop = false;
+    redoThisLoop = false;
+
+    // Run all passes on current SCC
+    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {  
+      Pass *P = getContainedPass(Index);
+
+      dumpPassInfo(P, EXECUTION_MSG, ON_LOOP_MSG, "");
+      dumpRequiredSet(P);
+
+      initializeAnalysisImpl(P);
+
+      LoopPass *LP = dynamic_cast<LoopPass *>(P);
+      {
+        PassManagerPrettyStackEntry X(LP, *CurrentLoop->getHeader());
+        StartPassTimer(P);
+        assert(LP && "Invalid LPPassManager member");
+        Changed |= LP->runOnLoop(CurrentLoop, *this);
+        StopPassTimer(P);
+      }
+
+      if (Changed)
+        dumpPassInfo(P, MODIFICATION_MSG, ON_LOOP_MSG, "");
+      dumpPreservedSet(P);
+
+      verifyPreservedAnalysis(LP);
+      removeNotPreservedAnalysis(P);
+      recordAvailableAnalysis(P);
+      removeDeadPasses(P, "", ON_LOOP_MSG);
+
+      // If dominator information is available then verify the info if requested.
+      verifyDomInfo(*LP, F);
+
+      if (skipThisLoop)
+        // Do not run other passes on this loop.
+        break;
+    }
+    
+    // Pop the loop from queue after running all passes.
+    LQ.pop_back();
+    
+    if (redoThisLoop)
+      LQ.push_back(CurrentLoop);
+  }
+  
+  // Finalization
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+    Pass *P = getContainedPass(Index);
+    LoopPass *LP = dynamic_cast <LoopPass *>(P);
+    if (LP)
+      Changed |= LP->doFinalization();
+  }
+
+  return Changed;
+}
+
+/// Print passes managed by this manager
+void LPPassManager::dumpPassStructure(unsigned Offset) {
+  llvm::cerr << std::string(Offset*2, ' ') << "Loop Pass Manager\n";
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+    Pass *P = getContainedPass(Index);
+    P->dumpPassStructure(Offset + 1);
+    dumpLastUses(P, Offset+1);
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+// LoopPass
+
+// Check if this pass is suitable for the current LPPassManager, if
+// available. This pass P is not suitable for a LPPassManager if P
+// is not preserving higher level analysis info used by other
+// LPPassManager passes. In such case, pop LPPassManager from the
+// stack. This will force assignPassManager() to create new
+// LPPassManger as expected.
+void LoopPass::preparePassManager(PMStack &PMS) {
+
+  // Find LPPassManager 
+  while (!PMS.empty() &&
+         PMS.top()->getPassManagerType() > PMT_LoopPassManager)
+    PMS.pop();
+
+  LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
+
+  // If this pass is destroying high level information that is used
+  // by other passes that are managed by LPM then do not insert
+  // this pass in current LPM. Use new LPPassManager.
+  if (LPPM && !LPPM->preserveHigherLevelAnalysis(this)) 
+    PMS.pop();
+}
+
+/// Assign pass manager to manage this pass.
+void LoopPass::assignPassManager(PMStack &PMS,
+                                 PassManagerType PreferredType) {
+  // Find LPPassManager 
+  while (!PMS.empty() &&
+         PMS.top()->getPassManagerType() > PMT_LoopPassManager)
+    PMS.pop();
+
+  LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
+
+  // Create new Loop Pass Manager if it does not exist. 
+  if (!LPPM) {
+
+    assert (!PMS.empty() && "Unable to create Loop Pass Manager");
+    PMDataManager *PMD = PMS.top();
+
+    // [1] Create new Call Graph Pass Manager
+    LPPM = new LPPassManager(PMD->getDepth() + 1);
+    LPPM->populateInheritedAnalysis(PMS);
+
+    // [2] Set up new manager's top level manager
+    PMTopLevelManager *TPM = PMD->getTopLevelManager();
+    TPM->addIndirectPassManager(LPPM);
+
+    // [3] Assign manager to manage this new manager. This may create
+    // and push new managers into PMS
+    Pass *P = dynamic_cast<Pass *>(LPPM);
+    TPM->schedulePass(P);
+
+    // [4] Push new manager into PMS
+    PMS.push(LPPM);
+  }
+
+  LPPM->add(this);
+}