Include GUIDs from the same module when computing GUIDs that needs to be imported.

Summary: In the compile phase of SamplePGO+ThinLTO, ICP is not invoked. Instead, indirect call targets will be included as function metadata for ThinIndex to buidl the call graph. This should not only include functions defined in other modules, but also functions defined in the same module, otherwise ThinIndex may find the callee dead and eliminate it, while ICP in backend will revive the symbol, which leads to undefined symbol.

Reviewers: tejohnson

Reviewed By: tejohnson

Subscribers: sanjoy, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D39480

llvm-svn: 317118

1 files changed, 16 insertions, 15 deletions

diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index bea55b3f4d0..34414f96cca 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -200,7 +200,7 @@ protected:
   const FunctionSamples *findFunctionSamples(const Instruction &I) const;
   bool inlineCallInstruction(Instruction *I);
   bool inlineHotFunctions(Function &F,
-                          DenseSet<GlobalValue::GUID> &ImportGUIDs);
+                          DenseSet<GlobalValue::GUID> &InlinedGUIDs);
   void printEdgeWeight(raw_ostream &OS, Edge E);
   void printBlockWeight(raw_ostream &OS, const BasicBlock *BB) const;
   void printBlockEquivalence(raw_ostream &OS, const BasicBlock *BB);
@@ -766,12 +766,12 @@ bool SampleProfileLoader::inlineCallInstruction(Instruction *I) {
 /// it to direct call. Each indirect call is limited with a single target.
 ///
 /// \param F function to perform iterative inlining.
-/// \param ImportGUIDs a set to be updated to include all GUIDs that come
-///     from a different module but inlined in the profiled binary.
+/// \param InlinedGUIDs a set to be updated to include all GUIDs that are
+///     inlined in the profiled binary.
 ///
 /// \returns True if there is any inline happened.
 bool SampleProfileLoader::inlineHotFunctions(
-    Function &F, DenseSet<GlobalValue::GUID> &ImportGUIDs) {
+    Function &F, DenseSet<GlobalValue::GUID> &InlinedGUIDs) {
   DenseSet<Instruction *> PromotedInsns;
   bool Changed = false;
   while (true) {
@@ -804,9 +804,9 @@ bool SampleProfileLoader::inlineHotFunctions(
         uint64_t Sum;
         for (const auto *FS : findIndirectCallFunctionSamples(*I, Sum)) {
           if (IsThinLTOPreLink) {
-            FS->findImportedFunctions(ImportGUIDs, F.getParent(),
-                                      Samples->getTotalSamples() *
-                                          SampleProfileHotThreshold / 100);
+            FS->findInlinedFunctions(InlinedGUIDs, F.getParent(),
+                                     Samples->getTotalSamples() *
+                                         SampleProfileHotThreshold / 100);
             continue;
           }
           auto CalleeFunctionName = FS->getName();
@@ -844,8 +844,8 @@ bool SampleProfileLoader::inlineHotFunctions(
         if (inlineCallInstruction(I))
           LocalChanged = true;
       } else if (IsThinLTOPreLink) {
-        findCalleeFunctionSamples(*I)->findImportedFunctions(
-            ImportGUIDs, F.getParent(),
+        findCalleeFunctionSamples(*I)->findInlinedFunctions(
+            InlinedGUIDs, F.getParent(),
             Samples->getTotalSamples() * SampleProfileHotThreshold / 100);
       }
     }
@@ -1455,18 +1455,19 @@ bool SampleProfileLoader::emitAnnotations(Function &F) {
   DEBUG(dbgs() << "Line number for the first instruction in " << F.getName()
                << ": " << getFunctionLoc(F) << "\n");
 
-  DenseSet<GlobalValue::GUID> ImportGUIDs;
-  Changed |= inlineHotFunctions(F, ImportGUIDs);
+  DenseSet<GlobalValue::GUID> InlinedGUIDs;
+  Changed |= inlineHotFunctions(F, InlinedGUIDs);
 
   // Compute basic block weights.
   Changed |= computeBlockWeights(F);
 
   if (Changed) {
     // Add an entry count to the function using the samples gathered at the
-    // function entry. Also sets the GUIDs that comes from a different
-    // module but inlined in the profiled binary. This is aiming at making
-    // the IR match the profiled binary before annotation.
-    F.setEntryCount(Samples->getHeadSamples() + 1, &ImportGUIDs);
+    // function entry.
+    // Sets the GUIDs that are inlined in the profiled binary. This is used
+    // for ThinLink to make correct liveness analysis, and also make the IR
+    // match the profiled binary before annotation.
+    F.setEntryCount(Samples->getHeadSamples() + 1, &InlinedGUIDs);
 
     // Compute dominance and loop info needed for propagation.
     computeDominanceAndLoopInfo(F);