Create a wrapper pass for BranchProbabilityInfo.

This new wrapper pass is useful when we want to do branch probability analysis conditionally (e.g. only in PGO mode) but don't want to add one more pass dependence.

http://reviews.llvm.org/D11241

llvm-svn: 242349

3 files changed, 63 insertions, 49 deletions

diff --git a/llvm/lib/Analysis/Analysis.cpp b/llvm/lib/Analysis/Analysis.cpp
index c839b2d284d..3ce87f9a76c 100644
--- a/llvm/lib/Analysis/Analysis.cpp
+++ b/llvm/lib/Analysis/Analysis.cpp
@@ -28,7 +28,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeNoAAPass(Registry);
   initializeBasicAliasAnalysisPass(Registry);
   initializeBlockFrequencyInfoWrapperPassPass(Registry);
-  initializeBranchProbabilityInfoPass(Registry);
+  initializeBranchProbabilityInfoWrapperPassPass(Registry);
   initializeCostModelAnalysisPass(Registry);
   initializeCFGViewerPass(Registry);
   initializeCFGPrinterPass(Registry);
diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
index be82f8cf1bc..46095ffd1d0 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
@@ -162,7 +162,7 @@ void BlockFrequencyInfo::print(raw_ostream &OS) const {
 
 INITIALIZE_PASS_BEGIN(BlockFrequencyInfoWrapperPass, "block-freq",
                       "Block Frequency Analysis", true, true)
-INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 INITIALIZE_PASS_END(BlockFrequencyInfoWrapperPass, "block-freq",
                     "Block Frequency Analysis", true, true)
@@ -183,7 +183,7 @@ void BlockFrequencyInfoWrapperPass::print(raw_ostream &OS,
 }
 
 void BlockFrequencyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<BranchProbabilityInfo>();
+  AU.addRequired<BranchProbabilityInfoWrapperPass>();
   AU.addRequired<LoopInfoWrapperPass>();
   AU.setPreservesAll();
 }
@@ -191,7 +191,8 @@ void BlockFrequencyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
 void BlockFrequencyInfoWrapperPass::releaseMemory() { BFI.releaseMemory(); }
 
 bool BlockFrequencyInfoWrapperPass::runOnFunction(Function &F) {
-  BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
+  BranchProbabilityInfo &BPI =
+      getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
   LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   BFI.calculate(F, BPI, LI);
   return false;
diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index 430b41241ed..b813dca9369 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -27,13 +27,13 @@ using namespace llvm;
 
 #define DEBUG_TYPE "branch-prob"
 
-INITIALIZE_PASS_BEGIN(BranchProbabilityInfo, "branch-prob",
+INITIALIZE_PASS_BEGIN(BranchProbabilityInfoWrapperPass, "branch-prob",
                       "Branch Probability Analysis", false, true)
 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_END(BranchProbabilityInfo, "branch-prob",
+INITIALIZE_PASS_END(BranchProbabilityInfoWrapperPass, "branch-prob",
                     "Branch Probability Analysis", false, true)
 
-char BranchProbabilityInfo::ID = 0;
+char BranchProbabilityInfoWrapperPass::ID = 0;
 
 // Weights are for internal use only. They are used by heuristics to help to
 // estimate edges' probability. Example:
@@ -319,8 +319,9 @@ bool BranchProbabilityInfo::calcPointerHeuristics(BasicBlock *BB) {
 
 // Calculate Edge Weights using "Loop Branch Heuristics". Predict backedges
 // as taken, exiting edges as not-taken.
-bool BranchProbabilityInfo::calcLoopBranchHeuristics(BasicBlock *BB) {
-  Loop *L = LI->getLoopFor(BB);
+bool BranchProbabilityInfo::calcLoopBranchHeuristics(BasicBlock *BB,
+                                                     const LoopInfo &LI) {
+  Loop *L = LI.getLoopFor(BB);
   if (!L)
     return false;
 
@@ -504,50 +505,11 @@ bool BranchProbabilityInfo::calcInvokeHeuristics(BasicBlock *BB) {
   return true;
 }
 
-void BranchProbabilityInfo::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<LoopInfoWrapperPass>();
-  AU.setPreservesAll();
-}
-
-bool BranchProbabilityInfo::runOnFunction(Function &F) {
-  DEBUG(dbgs() << "---- Branch Probability Info : " << F.getName()
-               << " ----\n\n");
-  LastF = &F; // Store the last function we ran on for printing.
-  LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-  assert(PostDominatedByUnreachable.empty());
-  assert(PostDominatedByColdCall.empty());
-
-  // Walk the basic blocks in post-order so that we can build up state about
-  // the successors of a block iteratively.
-  for (auto BB : post_order(&F.getEntryBlock())) {
-    DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n");
-    if (calcUnreachableHeuristics(BB))
-      continue;
-    if (calcMetadataWeights(BB))
-      continue;
-    if (calcColdCallHeuristics(BB))
-      continue;
-    if (calcLoopBranchHeuristics(BB))
-      continue;
-    if (calcPointerHeuristics(BB))
-      continue;
-    if (calcZeroHeuristics(BB))
-      continue;
-    if (calcFloatingPointHeuristics(BB))
-      continue;
-    calcInvokeHeuristics(BB);
-  }
-
-  PostDominatedByUnreachable.clear();
-  PostDominatedByColdCall.clear();
-  return false;
-}
-
 void BranchProbabilityInfo::releaseMemory() {
   Weights.clear();
 }
 
-void BranchProbabilityInfo::print(raw_ostream &OS, const Module *) const {
+void BranchProbabilityInfo::print(raw_ostream &OS) const {
   OS << "---- Branch Probabilities ----\n";
   // We print the probabilities from the last function the analysis ran over,
   // or the function it is currently running over.
@@ -688,3 +650,54 @@ BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS,
 
   return OS;
 }
+
+void BranchProbabilityInfo::calculate(Function &F, const LoopInfo& LI) {
+  DEBUG(dbgs() << "---- Branch Probability Info : " << F.getName()
+               << " ----\n\n");
+  LastF = &F; // Store the last function we ran on for printing.
+  assert(PostDominatedByUnreachable.empty());
+  assert(PostDominatedByColdCall.empty());
+
+  // Walk the basic blocks in post-order so that we can build up state about
+  // the successors of a block iteratively.
+  for (auto BB : post_order(&F.getEntryBlock())) {
+    DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n");
+    if (calcUnreachableHeuristics(BB))
+      continue;
+    if (calcMetadataWeights(BB))
+      continue;
+    if (calcColdCallHeuristics(BB))
+      continue;
+    if (calcLoopBranchHeuristics(BB, LI))
+      continue;
+    if (calcPointerHeuristics(BB))
+      continue;
+    if (calcZeroHeuristics(BB))
+      continue;
+    if (calcFloatingPointHeuristics(BB))
+      continue;
+    calcInvokeHeuristics(BB);
+  }
+
+  PostDominatedByUnreachable.clear();
+  PostDominatedByColdCall.clear();
+}
+
+void BranchProbabilityInfoWrapperPass::getAnalysisUsage(
+    AnalysisUsage &AU) const {
+  AU.addRequired<LoopInfoWrapperPass>();
+  AU.setPreservesAll();
+}
+
+bool BranchProbabilityInfoWrapperPass::runOnFunction(Function &F) {
+  const LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+  BPI.calculate(F, LI);
+  return false;
+}
+
+void BranchProbabilityInfoWrapperPass::releaseMemory() { BPI.releaseMemory(); }
+
+void BranchProbabilityInfoWrapperPass::print(raw_ostream &OS,
+                                             const Module *) const {
+  BPI.print(OS);
+}