Index: llvm/lib/Object/ELF.cpp
===================================================================
--- llvm/lib/Object/ELF.cpp
+++ llvm/lib/Object/ELF.cpp
@@ -438,6 +438,7 @@
 #include "llvm/BinaryFormat/DynamicTags.def"
 #undef HEXAGON_DYNAMIC_TAG
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
 
   case ELF::EM_MIPS:
     switch (Type) {
@@ -445,6 +446,7 @@
 #include "llvm/BinaryFormat/DynamicTags.def"
 #undef MIPS_DYNAMIC_TAG
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
 
   case ELF::EM_PPC64:
     switch (Type) {
@@ -452,6 +454,7 @@
 #include "llvm/BinaryFormat/DynamicTags.def"
 #undef PPC64_DYNAMIC_TAG
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   }
 #undef DYNAMIC_TAG
   switch (Type) {
Index: llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
===================================================================
--- llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
+++ llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
@@ -113,6 +113,7 @@
     case RT64_8:
       return IsPCRel ? ELF::R_X86_64_PC8 : ELF::R_X86_64_8;
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_GOT:
     switch (Type) {
     case RT64_64:
@@ -124,6 +125,7 @@
     case RT64_8:
       llvm_unreachable("Unimplemented");
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_GOTOFF:
     assert(Type == RT64_64);
     assert(!IsPCRel);
@@ -140,6 +142,7 @@
     case RT64_8:
       llvm_unreachable("Unimplemented");
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_DTPOFF:
     assert(!IsPCRel);
     switch (Type) {
@@ -152,6 +155,7 @@
     case RT64_8:
       llvm_unreachable("Unimplemented");
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_SIZE:
     assert(!IsPCRel);
     switch (Type) {
@@ -164,6 +168,7 @@
     case RT64_8:
       llvm_unreachable("Unimplemented");
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_TLSCALL:
     return ELF::R_X86_64_TLSDESC_CALL;
   case MCSymbolRefExpr::VK_TLSDESC:
@@ -196,6 +201,7 @@
     case X86::reloc_riprel_4byte_movq_load:
       return ELF::R_X86_64_REX_GOTPCRELX;
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   }
 }
 
@@ -233,6 +239,7 @@
     case RT32_8:
       return IsPCRel ? ELF::R_386_PC8 : ELF::R_386_8;
     }
+    llvm_unreachable("Previous switch() should have return'ed!");
   case MCSymbolRefExpr::VK_GOT:
     assert(Type == RT32_32);
     if (IsPCRel)