From fa43892d6fdf77e373dcf54f1c934380b8731df2 Mon Sep 17 00:00:00 2001
From: Steven Wu <stevenwu@apple.com>
Date: Tue, 13 Nov 2018 17:35:04 +0000
Subject: Revert "[ThinLTO] Internalize readonly globals"

This reverts commit 10c84a8f35cae4a9fc421648d9608fccda3925f2.

llvm-svn: 346768
---
 llvm/lib/Transforms/IPO/FunctionImport.cpp | 45 ++++--------------------------
 1 file changed, 5 insertions(+), 40 deletions(-)

(limited to 'llvm/lib/Transforms/IPO/FunctionImport.cpp')

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 60ca8e32897..1196dd0099b 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -294,8 +294,10 @@ static void computeImportForReferencedGlobals(
     LLVM_DEBUG(dbgs() << " ref -> " << VI << "\n");
 
     for (auto &RefSummary : VI.getSummaryList())
-      if (isa<GlobalVarSummary>(RefSummary.get()) &&
-          canImportGlobalVar(RefSummary.get())) {
+      if (RefSummary->getSummaryKind() == GlobalValueSummary::GlobalVarKind &&
+          !RefSummary->notEligibleToImport() &&
+          !GlobalValue::isInterposableLinkage(RefSummary->linkage()) &&
+          RefSummary->refs().empty()) {
         auto ILI = ImportList[RefSummary->modulePath()].insert(VI.getGUID());
         // Only update stat if we haven't already imported this variable.
         if (ILI.second)
@@ -822,25 +824,6 @@ void llvm::computeDeadSymbols(
   NumLiveSymbols += LiveSymbols;
 }
 
-// Compute dead symbols and propagate constants in combined index.
-void llvm::computeDeadSymbolsWithConstProp(
-    ModuleSummaryIndex &Index,
-    const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols,
-    function_ref<PrevailingType(GlobalValue::GUID)> isPrevailing,
-    bool ImportEnabled) {
-  computeDeadSymbols(Index, GUIDPreservedSymbols, isPrevailing);
-  if (ImportEnabled) {
-    Index.propagateConstants(GUIDPreservedSymbols);
-  } else {
-    // If import is disabled we should drop read-only attribute
-    // from all summaries to prevent internalization.
-    for (auto &P : Index)
-      for (auto &S : P.second.SummaryList)
-        if (auto *GVS = dyn_cast<GlobalVarSummary>(S.get()))
-          GVS->setReadOnly(false);
-  }
-}
-
 /// Compute the set of summaries needed for a ThinLTO backend compilation of
 /// \p ModulePath.
 void llvm::gatherImportedSummariesForModule(
@@ -1037,22 +1020,6 @@ static Function *replaceAliasWithAliasee(Module *SrcModule, GlobalAlias *GA) {
   return NewFn;
 }
 
-// Internalize values that we marked with specific attribute
-// in processGlobalForThinLTO.
-static void internalizeImmutableGVs(Module &M) {
-  for (auto &GV : M.globals()) {
-    // Skip GVs which have been converted to declarations
-    // by dropDeadSymbols.
-    if (GV.isDeclaration())
-      continue;
-    if (auto *GVar = dyn_cast<GlobalVariable>(&GV))
-      if (GVar->hasAttribute("thinlto-internalize")) {
-        GVar->setLinkage(GlobalValue::InternalLinkage);
-        GVar->setVisibility(GlobalValue::DefaultVisibility);
-      }
-  }
-}
-
 // Automatically import functions in Module \p DestModule based on the summaries
 // index.
 Expected<bool> FunctionImporter::importFunctions(
@@ -1176,8 +1143,6 @@ Expected<bool> FunctionImporter::importFunctions(
     NumImportedModules++;
   }
 
-  internalizeImmutableGVs(DestModule);
-
   NumImportedFunctions += (ImportedCount - ImportedGVCount);
   NumImportedGlobalVars += ImportedGVCount;
 
@@ -1194,7 +1159,7 @@ static bool doImportingForModule(Module &M) {
   if (SummaryFile.empty())
     report_fatal_error("error: -function-import requires -summary-file\n");
   Expected<std::unique_ptr<ModuleSummaryIndex>> IndexPtrOrErr =
-      getModuleSummaryIndexForFile(SummaryFile);  
+      getModuleSummaryIndexForFile(SummaryFile);
   if (!IndexPtrOrErr) {
     logAllUnhandledErrors(IndexPtrOrErr.takeError(), errs(),
                           "Error loading file '" + SummaryFile + "': ");
-- 
cgit v1.2.3