Add RegionPass support.

A RegionPass is executed like a LoopPass but on the regions detected by the
RegionInfo pass instead of the loops detected by the LoopInfo pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116905 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 276 insertions, 0 deletions

diff --git a/lib/Analysis/RegionPass.cpp b/lib/Analysis/RegionPass.cpp
new file mode 100644
index 0000000000..a4145e15e4
--- /dev/null
+++ b/lib/Analysis/RegionPass.cpp
@@ -0,0 +1,276 @@
+//===- RegionPass.cpp - Region Pass and Region 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 RegionPass and RGPassManager. All region optimization
+// and transformation passes are derived from RegionPass. RGPassManager is
+// responsible for managing RegionPasses.
+// most of these codes are COPY from LoopPass.cpp
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/Analysis/RegionPass.h"
+#include "llvm/Analysis/RegionIterator.h"
+#include "llvm/Support/Timer.h"
+
+#define DEBUG_TYPE "regionpassmgr"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// RGPassManager
+//
+
+char RGPassManager::ID = 0;
+
+RGPassManager::RGPassManager(int Depth)
+  : FunctionPass(ID), PMDataManager(Depth) {
+  skipThisRegion = false;
+  redoThisRegion = false;
+  RI = NULL;
+  CurrentRegion = NULL;
+}
+
+// Recurse through all subregions and all regions  into RQ.
+static void addRegionIntoQueue(Region *R, std::deque<Region *> &RQ) {
+  RQ.push_back(R);
+  for (Region::iterator I = R->begin(), E = R->end(); I != E; ++I)
+    addRegionIntoQueue(*I, RQ);
+}
+
+/// Pass Manager itself does not invalidate any analysis info.
+void RGPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
+  Info.addRequired<RegionInfo>();
+  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 RGPassManager::runOnFunction(Function &F) {
+  RI = &getAnalysis<RegionInfo>();
+  bool Changed = false;
+
+  // Collect inherited analysis from Module level pass manager.
+  populateInheritedAnalysis(TPM->activeStack);
+
+  addRegionIntoQueue(RI->getTopLevelRegion(), RQ);
+
+  if (RQ.empty()) // No regions, skip calling finalizers
+    return false;
+
+  // Initialization
+  for (std::deque<Region *>::const_iterator I = RQ.begin(), E = RQ.end();
+       I != E; ++I) {
+    Region *R = *I;
+    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+      RegionPass *RP = (RegionPass *)getContainedPass(Index);
+      Changed |= RP->doInitialization(R, *this);
+    }
+  }
+
+  // Walk Regions
+  while (!RQ.empty()) {
+
+    CurrentRegion  = RQ.back();
+    skipThisRegion = false;
+    redoThisRegion = false;
+
+    // Run all passes on the current Region.
+    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+      RegionPass *P = (RegionPass*)getContainedPass(Index);
+
+      dumpPassInfo(P, EXECUTION_MSG, ON_REGION_MSG,
+                   CurrentRegion->getNameStr());
+      dumpRequiredSet(P);
+
+      initializeAnalysisImpl(P);
+
+      {
+        PassManagerPrettyStackEntry X(P, *CurrentRegion->getEntry());
+
+        TimeRegion PassTimer(getPassTimer(P));
+        Changed |= P->runOnRegion(CurrentRegion, *this);
+      }
+
+      if (Changed)
+        dumpPassInfo(P, MODIFICATION_MSG, ON_REGION_MSG,
+                     skipThisRegion ? "<deleted>" :
+                                    CurrentRegion->getNameStr());
+      dumpPreservedSet(P);
+
+      if (!skipThisRegion) {
+        // Manually check that this region is still healthy. This is done
+        // instead of relying on RegionInfo::verifyRegion since RegionInfo
+        // is a function pass and it's really expensive to verify every
+        // Region in the function every time. That level of checking can be
+        // enabled with the -verify-region-info option.
+        {
+          TimeRegion PassTimer(getPassTimer(P));
+          CurrentRegion->verifyRegion();
+        }
+
+        // Then call the regular verifyAnalysis functions.
+        verifyPreservedAnalysis(P);
+      }
+
+      removeNotPreservedAnalysis(P);
+      recordAvailableAnalysis(P);
+      removeDeadPasses(P,
+                       skipThisRegion ? "<deleted>" :
+                                      CurrentRegion->getNameStr(),
+                       ON_REGION_MSG);
+
+      if (skipThisRegion)
+        // Do not run other passes on this region.
+        break;
+    }
+
+    // If the region was deleted, release all the region passes. This frees up
+    // some memory, and avoids trouble with the pass manager trying to call
+    // verifyAnalysis on them.
+    if (skipThisRegion)
+      for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+        Pass *P = getContainedPass(Index);
+        freePass(P, "<deleted>", ON_REGION_MSG);
+      }
+
+    // Pop the region from queue after running all passes.
+    RQ.pop_back();
+
+    if (redoThisRegion)
+      RQ.push_back(CurrentRegion);
+
+    // Free all region nodes created in region passes.
+    RI->clearNodeCache();
+  }
+
+  // Finalization
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+    RegionPass *P = (RegionPass*)getContainedPass(Index);
+    Changed |= P->doFinalization();
+  }
+
+  // Print the region tree after all pass.
+  DEBUG(
+    dbgs() << "\nRegion tree of function " << F.getName()
+           << " after all region Pass:\n";
+    RI->dump();
+    dbgs() << "\n";
+    );
+
+  return Changed;
+}
+
+/// Print passes managed by this manager
+void RGPassManager::dumpPassStructure(unsigned Offset) {
+  errs().indent(Offset*2) << "Region Pass Manager\n";
+  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+    Pass *P = getContainedPass(Index);
+    P->dumpPassStructure(Offset + 1);
+    dumpLastUses(P, Offset+1);
+  }
+}
+
+namespace {
+//===----------------------------------------------------------------------===//
+// PrintRegionPass
+class PrintRegionPass : public RegionPass {
+private:
+  std::string Banner;
+  raw_ostream &Out;       // raw_ostream to print on.
+
+public:
+  static char ID;
+  PrintRegionPass() : RegionPass(ID), Out(dbgs()) {}
+  PrintRegionPass(const std::string &B, raw_ostream &o)
+      : RegionPass(ID), Banner(B), Out(o) {}
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesAll();
+  }
+
+  virtual bool runOnRegion(Region *R, RGPassManager &RGM) {
+    Out << Banner;
+    for (Region::block_iterator I = R->block_begin(), E = R->block_end();
+         I != E; ++I)
+      (*I)->getEntry()->print(Out);
+
+    return false;
+  }
+};
+
+char PrintRegionPass::ID = 0;
+}  //end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// RegionPass
+
+// Check if this pass is suitable for the current RGPassManager, if
+// available. This pass P is not suitable for a RGPassManager if P
+// is not preserving higher level analysis info used by other
+// RGPassManager passes. In such case, pop RGPassManager from the
+// stack. This will force assignPassManager() to create new
+// LPPassManger as expected.
+void RegionPass::preparePassManager(PMStack &PMS) {
+
+  // Find RGPassManager
+  while (!PMS.empty() &&
+         PMS.top()->getPassManagerType() > PMT_RegionPassManager)
+    PMS.pop();
+
+
+  // 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 RGPassManager.
+  if (PMS.top()->getPassManagerType() == PMT_RegionPassManager &&
+    !PMS.top()->preserveHigherLevelAnalysis(this))
+    PMS.pop();
+}
+
+/// Assign pass manager to manage this pass.
+void RegionPass::assignPassManager(PMStack &PMS,
+                                 PassManagerType PreferredType) {
+  // Find RGPassManager
+  while (!PMS.empty() &&
+         PMS.top()->getPassManagerType() > PMT_RegionPassManager)
+    PMS.pop();
+
+  RGPassManager *RGPM;
+
+  // Create new Region Pass Manager if it does not exist.
+  if (PMS.top()->getPassManagerType() == PMT_RegionPassManager)
+    RGPM = (RGPassManager*)PMS.top();
+  else {
+
+    assert (!PMS.empty() && "Unable to create Region Pass Manager");
+    PMDataManager *PMD = PMS.top();
+
+    // [1] Create new Call Graph Pass Manager
+    RGPM = new RGPassManager(PMD->getDepth() + 1);
+    RGPM->populateInheritedAnalysis(PMS);
+
+    // [2] Set up new manager's top level manager
+    PMTopLevelManager *TPM = PMD->getTopLevelManager();
+    TPM->addIndirectPassManager(RGPM);
+
+    // [3] Assign manager to manage this new manager. This may create
+    // and push new managers into PMS
+    Pass *P = dynamic_cast<Pass *>(RGPM);
+    TPM->schedulePass(P);
+
+    // [4] Push new manager into PMS
+    PMS.push(RGPM);
+  }
+
+  RGPM->add(this);
+}
+
+/// Get the printer pass
+Pass *RegionPass::createPrinterPass(raw_ostream &O,
+                                  const std::string &Banner) const {
+  return new PrintRegionPass(Banner, O);
+}