Index: lib/CodeGen/TargetLoweringObjectFileImpl.cpp
===================================================================
--- lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -412,6 +412,9 @@
       Name.startswith(".llvm.linkonce.sb."))
     return SectionKind::getBSS();
 
+  if (Name == ".rodata" || Name.startswith(".rodata."))
+    return SectionKind::getReadOnly();
+
   if (Name == ".tdata" ||
       Name.startswith(".tdata.") ||
       Name.startswith(".gnu.linkonce.td.") ||
@@ -424,6 +427,9 @@
       Name.startswith(".llvm.linkonce.tb."))
     return SectionKind::getThreadBSS();
 
+  if (Name.startswith(".debug_"))
+    return SectionKind::getMetadata();
+
   return K;
 }
 
Index: lib/MC/MCContext.cpp
===================================================================
--- lib/MC/MCContext.cpp
+++ lib/MC/MCContext.cpp
@@ -394,6 +394,15 @@
   auto IterBool = ELFUniquingMap.insert(
       std::make_pair(ELFSectionKey{Section.str(), Group, UniqueID}, nullptr));
   auto &Entry = *IterBool.first;
+  MCSectionELF *&Sec = Entry.second;
+  if (!IterBool.second) {
+    // We want to let users add additional flags even for sections with
+    // defaults. For example, .debug_str has "MS" flags by default and user
+    // might want to add "E".
+    Sec->setFlags(Sec->getFlags() | Flags);
+    return Sec;
+  }
+
   if (!IterBool.second)
     return Entry.second;
 
@@ -407,10 +416,9 @@
   else
     Kind = SectionKind::getReadOnly();
 
-  MCSectionELF *Result = createELFSectionImpl(
-      CachedName, Type, Flags, Kind, EntrySize, GroupSym, UniqueID, Associated);
-  Entry.second = Result;
-  return Result;
+  Sec = createELFSectionImpl(CachedName, Type, Flags, Kind, EntrySize, GroupSym,
+                             UniqueID, Associated);
+  return Sec;
 }
 
 MCSectionELF *MCContext::createELFGroupSection(const MCSymbolELF *Group) {