[llvm] r246066 - Fix memory leak in sample profile pass.

[Diego Novillo via llvm-commits]

Author: dnovillo
Date: Wed Aug 26 15:00:27 2015
New Revision: 246066

URL: http://llvm.org/viewvc/llvm-project?rev=246066&view=rev
Log:
Fix memory leak in sample profile pass.

The problem here were the function analyses invoked by the function pass
manager from the new IPO pass. I looked at other IPO passes needing
dominance information and the only one that requires it (partial
inliner) does not use the standard dependency mechanism.

This patch mimics what the partial inliner does to compute dominance,
post-dominance and loop info. One thing I like about this approach is
that I can delay the computation of all this until I actually need it.

This should bring the ASAN buildbot back to green. If there's a better
way to fix this, I'll do it in a follow-up patch.

Modified:
    llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp

Modified: llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp?rev=246066&r1=246065&r2=246066&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp Wed Aug 26 15:00:27 2015
@@ -80,9 +80,8 @@ public:
   static char ID;
 
   SampleProfileLoader(StringRef Name = SampleProfileFile)
-      : ModulePass(ID), DT(nullptr), PDT(nullptr), LI(nullptr),
-        Ctx(nullptr), Reader(), Samples(nullptr), Filename(Name),
-        ProfileIsValid(false) {
+      : ModulePass(ID), DT(nullptr), PDT(nullptr), LI(nullptr), Reader(),
+        Samples(nullptr), Filename(Name), ProfileIsValid(false) {
     initializeSampleProfileLoaderPass(*PassRegistry::getPassRegistry());
   }
 
@@ -96,15 +95,6 @@ public:
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
-
-    AU.addRequired<LoopInfoWrapperPass>();
-    AU.addPreserved<LoopInfoWrapperPass>();
-
-    AU.addRequired<DominatorTreeWrapperPass>();
-    AU.addPreserved<DominatorTreeWrapperPass>();
-
-    AU.addRequired<PostDominatorTree>();
-    AU.addPreserved<PostDominatorTree>();
   }
 
 protected:
@@ -125,6 +115,7 @@ protected:
   unsigned visitEdge(Edge E, unsigned *NumUnknownEdges, Edge *UnknownEdge);
   void buildEdges(Function &F);
   bool propagateThroughEdges(Function &F);
+  void computeDominanceAndLoopInfo(Function &F);
 
   /// \brief Line number for the function header. Used to compute absolute
   /// line numbers from the relative line numbers found in the profile.
@@ -157,9 +148,9 @@ protected:
   EquivalenceClassMap EquivalenceClass;
 
   /// \brief Dominance, post-dominance and loop information.
-  DominatorTree *DT;
-  PostDominatorTree *PDT;
-  LoopInfo *LI;
+  std::unique_ptr<DominatorTree> DT;
+  std::unique_ptr<DominatorTreeBase<BasicBlock>> PDT;
+  std::unique_ptr<LoopInfo> LI;
 
   /// \brief Predecessors for each basic block in the CFG.
   BlockEdgeMap Predecessors;
@@ -167,9 +158,6 @@ protected:
   /// \brief Successors for each basic block in the CFG.
   BlockEdgeMap Successors;
 
-  /// \brief LLVM context holding the debug data we need.
-  LLVMContext *Ctx;
-
   /// \brief Profile reader object.
   std::unique_ptr<SampleProfileReader> Reader;
 
@@ -372,7 +360,7 @@ void SampleProfileLoader::findEquivalenc
     // class by making BB2's equivalence class be BB1.
     DominatedBBs.clear();
     DT->getDescendants(BB1, DominatedBBs);
-    findEquivalencesFor(BB1, DominatedBBs, PDT->DT);
+    findEquivalencesFor(BB1, DominatedBBs, PDT.get());
 
     // Repeat the same logic for all the blocks post-dominated by BB1.
     // We are looking for every basic block BB2 such that:
@@ -384,7 +372,7 @@ void SampleProfileLoader::findEquivalenc
     // If all those conditions hold, BB2's equivalence class is BB1.
     DominatedBBs.clear();
     PDT->getDescendants(BB1, DominatedBBs);
-    findEquivalencesFor(BB1, DominatedBBs, DT);
+    findEquivalencesFor(BB1, DominatedBBs, DT.get());
 
     DEBUG(printBlockEquivalence(dbgs(), BB1));
   }
@@ -666,6 +654,17 @@ unsigned SampleProfileLoader::getFunctio
   return 0;
 }
 
+void SampleProfileLoader::computeDominanceAndLoopInfo(Function &F) {
+  DT.reset(new DominatorTree);
+  DT->recalculate(F);
+
+  PDT.reset(new DominatorTreeBase<BasicBlock>(true));
+  PDT->recalculate(F);
+
+  LI.reset(new LoopInfo);
+  LI->analyze(*DT);
+}
+
 /// \brief Generate branch weight metadata for all branches in \p F.
 ///
 /// Branch weights are computed out of instruction samples using a
@@ -730,6 +729,9 @@ bool SampleProfileLoader::emitAnnotation
   Changed |= computeBlockWeights(F);
 
   if (Changed) {
+    // Compute dominance and loop info needed for propagation.
+    computeDominanceAndLoopInfo(F);
+
     // Find equivalence classes.
     findEquivalenceClasses(F);
 
@@ -743,15 +745,12 @@ bool SampleProfileLoader::emitAnnotation
 char SampleProfileLoader::ID = 0;
 INITIALIZE_PASS_BEGIN(SampleProfileLoader, "sample-profile",
                       "Sample Profile loader", false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(AddDiscriminators)
 INITIALIZE_PASS_END(SampleProfileLoader, "sample-profile",
                     "Sample Profile loader", false, false)
 
 bool SampleProfileLoader::doInitialization(Module &M) {
-  auto& Ctx = M.getContext();
+  auto &Ctx = M.getContext();
   auto ReaderOrErr = SampleProfileReader::create(Filename, Ctx);
   if (std::error_code EC = ReaderOrErr.getError()) {
     std::string Msg = "Could not open profile: " + EC.message();
@@ -783,10 +782,6 @@ bool SampleProfileLoader::runOnFunction(
   if (!ProfileIsValid)
     return false;
 
-  DT = &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
-  PDT = &getAnalysis<PostDominatorTree>(F);
-  LI = &getAnalysis<LoopInfoWrapperPass>(F).getLoopInfo();
-  Ctx = &F.getParent()->getContext();
   Samples = Reader->getSamplesFor(F);
   if (!Samples->empty())
     return emitAnnotations(F);