SamplePGO - Clear per-function data after applying a profile.

The pass was keeping around a lot of per-function data (visited blocks,
edges, dominance, etc) that is just taking up memory for no reason. In
fact, from function to function it could potentially confuse the
propagator since some maps are indexed by line offsets which can be
common between functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251531 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/SampleProfile.cpp b/lib/Transforms/IPO/SampleProfile.cpp
index 49ebf6555b6aa49e7f6fc2bed1ee1ecbc8994d5d..8fd81d62dd80073ffd68382b7f688e43023806b3 100644 (file)
--- a/lib/Transforms/IPO/SampleProfile.cpp
+++ b/lib/Transforms/IPO/SampleProfile.cpp
@@ -123,6 +123,7 @@ protected:
   bool propagateThroughEdges(Function &F);
   void computeDominanceAndLoopInfo(Function &F);
   unsigned getOffset(unsigned L, unsigned H) const;
+  void clearFunctionData();
 
   /// \brief Map basic blocks to their computed weights.
   ///
@@ -175,6 +176,20 @@ protected:
 };
 }
 
+/// Clear all the per-function data used to load samples and propagate weights.
+void SampleProfileLoader::clearFunctionData() {
+  BlockWeights.clear();
+  EdgeWeights.clear();
+  VisitedBlocks.clear();
+  VisitedEdges.clear();
+  EquivalenceClass.clear();
+  DT = nullptr;
+  PDT = nullptr;
+  LI = nullptr;
+  Predecessors.clear();
+  Successors.clear();
+}
+
 /// \brief Returns the offset of lineno \p L to head_lineno \p H
 ///
 /// \param L  Lineno
@@ -931,17 +946,19 @@ ModulePass *llvm::createSampleProfileLoaderPass(StringRef Name) {
 }
 
 bool SampleProfileLoader::runOnModule(Module &M) {
+  if (!ProfileIsValid)
+    return false;
+
   bool retval = false;
   for (auto &F : M)
-    if (!F.isDeclaration())
+    if (!F.isDeclaration()) {
+      clearFunctionData();
       retval |= runOnFunction(F);
+    }
   return retval;
 }
 
 bool SampleProfileLoader::runOnFunction(Function &F) {
-  if (!ProfileIsValid)
-    return false;
-
   Samples = Reader->getSamplesFor(F);
   if (!Samples->empty())
     return emitAnnotations(F);