Revert "[ThinLTO] Add summary entries for index-based WPD"

Mistaken commit of something still under review!

This reverts commit r351453.

llvm-svn: 351455

1 files changed, 4 insertions, 111 deletions

diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index af3d97a03cd..87f76d43bb1 100644
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -406,98 +406,9 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
   Index.addGlobalValueSummary(F, std::move(FuncSummary));
 }
 
-/// Find function pointers referenced within the given vtable initializer
-/// (or subset of an initializer) \p I. The starting offset of \p I within
-/// the vtable initializer is \p StartingOffset. Any discovered function
-/// pointers are added to \p VTableFuncs along with their cumulative offset
-/// within the initializer.
-static void findFuncPointers(const Constant *I, uint64_t StartingOffset,
-                             const Module &M, ModuleSummaryIndex &Index,
-                             VTableFuncList &VTableFuncs) {
-  // First check if this is a function pointer.
-  if (I->getType()->isPointerTy()) {
-    auto Fn = dyn_cast<Function>(I->stripPointerCasts());
-    // We can disregard __cxa_pure_virtual as a possible call target, as
-    // calls to pure virtuals are UB.
-    if (Fn && Fn->getName() != "__cxa_pure_virtual")
-      VTableFuncs.push_back(
-          std::make_pair(Index.getOrInsertValueInfo(Fn), StartingOffset));
-    return;
-  }
-
-  // Walk through the elements in the constant struct or array and recursively
-  // look for virtual function pointers.
-  const DataLayout &DL = M.getDataLayout();
-  if (auto *C = dyn_cast<ConstantStruct>(I)) {
-    StructType *STy = dyn_cast<StructType>(C->getType());
-    assert(STy);
-    const StructLayout *SL = DL.getStructLayout(C->getType());
-
-    for (StructType::element_iterator EB = STy->element_begin(), EI = EB,
-                                      EE = STy->element_end();
-         EI != EE; ++EI) {
-      auto Offset = SL->getElementOffset(EI - EB);
-      unsigned Op = SL->getElementContainingOffset(Offset);
-      findFuncPointers(cast<Constant>(I->getOperand(Op)),
-                       StartingOffset + Offset, M, Index, VTableFuncs);
-    }
-  } else if (auto *C = dyn_cast<ConstantArray>(I)) {
-    ArrayType *ATy = C->getType();
-    Type *EltTy = ATy->getElementType();
-    uint64_t EltSize = DL.getTypeAllocSize(EltTy);
-    for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
-      findFuncPointers(cast<Constant>(I->getOperand(i)),
-                       StartingOffset + i * EltSize, M, Index, VTableFuncs);
-    }
-  }
-}
-
-// Identify the function pointers referenced by vtable definition \p V.
-static void computeVTableFuncs(ModuleSummaryIndex &Index,
-                               const GlobalVariable &V, const Module &M,
-                               VTableFuncList &VTableFuncs) {
-  if (!V.isConstant())
-    return;
-
-  findFuncPointers(V.getInitializer(), /*StartingOffset=*/0, M, Index,
-                   VTableFuncs);
-
-#ifndef NDEBUG
-  // Validate that the VTableFuncs list is ordered by offset.
-  uint64_t PrevOffset = 0;
-  for (auto &P : VTableFuncs) {
-    // The findVFuncPointers traversal should have encountered the
-    // functions in offset order. We need to use ">=" since PrevOffset
-    // starts at 0.
-    assert(P.second >= PrevOffset);
-    PrevOffset = P.second;
-  }
-#endif
-}
-
-/// Record vtable definition \p V for each type metadata it references.
-static void recordTypeIdMetadataReferences(ModuleSummaryIndex &Index,
-                                           const GlobalVariable &V,
-                                           SmallVectorImpl<MDNode *> &Types) {
-  for (MDNode *Type : Types) {
-    auto TypeID = Type->getOperand(1).get();
-
-    uint64_t Offset =
-        cast<ConstantInt>(
-            cast<ConstantAsMetadata>(Type->getOperand(0))->getValue())
-            ->getZExtValue();
-
-    if (auto *TypeId = dyn_cast<MDString>(TypeID))
-      Index.getOrInsertTypeIdMetadataSummary(TypeId->getString())
-          .push_back({Offset, Index.getOrInsertValueInfo(&V)});
-  }
-}
-
-static void computeVariableSummary(ModuleSummaryIndex &Index,
-                                   const GlobalVariable &V,
-                                   DenseSet<GlobalValue::GUID> &CantBePromoted,
-                                   const Module &M,
-                                   SmallVectorImpl<MDNode *> &Types) {
+static void
+computeVariableSummary(ModuleSummaryIndex &Index, const GlobalVariable &V,
+                       DenseSet<GlobalValue::GUID> &CantBePromoted) {
   SetVector<ValueInfo> RefEdges;
   SmallPtrSet<const User *, 8> Visited;
   bool HasBlockAddress = findRefEdges(Index, &V, RefEdges, Visited);
@@ -505,21 +416,6 @@ static void computeVariableSummary(ModuleSummaryIndex &Index,
   GlobalValueSummary::GVFlags Flags(V.getLinkage(), NonRenamableLocal,
                                     /* Live = */ false, V.isDSOLocal());
 
-  VTableFuncList VTableFuncs;
-  // If splitting is not enabled, then we compute the summary information
-  // necessary for index-based whole program devirtualization.
-  if (!Index.enableSplitLTOUnit()) {
-    Types.clear();
-    V.getMetadata(LLVMContext::MD_type, Types);
-    if (!Types.empty()) {
-      // Identify the function pointers referenced by this vtable definition.
-      computeVTableFuncs(Index, V, M, VTableFuncs);
-
-      // Record this vtable definition for each type metadata it references.
-      recordTypeIdMetadataReferences(Index, V, Types);
-    }
-  }
-
   // Don't mark variables we won't be able to internalize as read-only.
   GlobalVarSummary::GVarFlags VarFlags(
       !V.hasComdat() && !V.hasAppendingLinkage() && !V.isInterposable() &&
@@ -530,8 +426,6 @@ static void computeVariableSummary(ModuleSummaryIndex &Index,
     CantBePromoted.insert(V.getGUID());
   if (HasBlockAddress)
     GVarSummary->setNotEligibleToImport();
-  if (!VTableFuncs.empty())
-    GVarSummary->setVTableFuncs(VTableFuncs);
   Index.addGlobalValueSummary(V, std::move(GVarSummary));
 }
 
@@ -674,11 +568,10 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex(
 
   // Compute summaries for all variables defined in module, and save in the
   // index.
-  SmallVector<MDNode *, 2> Types;
   for (const GlobalVariable &G : M.globals()) {
     if (G.isDeclaration())
       continue;
-    computeVariableSummary(Index, G, CantBePromoted, M, Types);
+    computeVariableSummary(Index, G, CantBePromoted);
   }
 
   // Compute summaries for all aliases defined in module, and save in the