Bitcode: Make the summary reader responsible for merging. NFCI.

This is to prepare for an upcoming change which uses pointers instead of
GUIDs to represent references.

Differential Revision: https://reviews.llvm.org/D32469

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301843 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/ModuleSummaryIndex.cpp

@@ -16,42 +16,6 @@
 #include "llvm/ADT/StringMap.h"
 using namespace llvm;
 
-// Create the combined module index/summary from multiple
-// per-module instances.
-void ModuleSummaryIndex::mergeFrom(std::unique_ptr<ModuleSummaryIndex> Other,
-                                   uint64_t NextModuleId) {
-  if (Other->modulePaths().empty())
-    return;
-
-  assert(Other->modulePaths().size() == 1 &&
-         "Can only merge from an single-module index at that time");
-
-  StringRef OtherModPath = Other->modulePaths().begin()->first();
-  StringRef ModPath = addModulePath(OtherModPath, NextModuleId,
-                                    Other->getModuleHash(OtherModPath))
-                          ->first();
-
-  for (auto &OtherGlobalValSummaryLists : *Other) {
-    GlobalValue::GUID ValueGUID = OtherGlobalValSummaryLists.first;
-    GlobalValueSummaryList &List = OtherGlobalValSummaryLists.second;
-
-    // Assert that the value summary list only has one entry, since we shouldn't
-    // have duplicate names within a single per-module index.
-    assert(List.size() == 1);
-    std::unique_ptr<GlobalValueSummary> Summary = std::move(List.front());
-
-    // Note the module path string ref was copied above and is still owned by
-    // the original per-module index. Reset it to the new module path
-    // string reference owned by the combined index.
-    Summary->setModulePath(ModPath);
-
-    // Add new value summary to existing list. There may be duplicates when
-    // combining GlobalValueMap entries, due to COMDAT values. Any local
-    // values were given unique global IDs.
-    addGlobalValueSummary(ValueGUID, std::move(Summary));
-  }
-}
-
 // Collect for the given module the list of function it defines
 // (GUID -> Summary).
 void ModuleSummaryIndex::collectDefinedFunctionsForModule(