Revert "[ThinLTO] Add an auto-hide feature"

This reverts commit r293970.

After more discussion, this belongs to the linker side and
there is no added value to do it at this level.

llvm-svn: 293993

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -800,14 +800,13 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
   // like getDecodedLinkage() above. Any future change to the linkage enum and
   // to getDecodedLinkage() will need to be taken into account here as above.
   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
-  bool NotEligibleToImport = ((RawFlags >> 4) & 0x1) || Version < 3;
+  RawFlags = RawFlags >> 4;
+  bool NotEligibleToImport = (RawFlags & 0x1) || Version < 3;
   // The LiveRoot flag wasn't introduced until version 3. For dead stripping
   // to work correctly on earlier versions, we must conservatively treat all
   // values as live.
-  bool LiveRoot = ((RawFlags >> 5) & 0x1) || Version < 3;
-  bool AutoHide = (RawFlags >> 6) & 0x1;
-  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, LiveRoot,
-                                     AutoHide);
+  bool LiveRoot = (RawFlags & 0x2) || Version < 3;
+  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, LiveRoot);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {