Index: lldb/source/Target/Platform.cpp
===================================================================
--- lldb/source/Target/Platform.cpp
+++ lldb/source/Target/Platform.cpp
@@ -1822,6 +1822,7 @@
 size_t Platform::GetSoftwareBreakpointTrapOpcode(Target &target,
                                                  BreakpointSite *bp_site) {
   ArchSpec arch = target.GetArchitecture();
+  assert(arch.IsValid());
   const uint8_t *trap_opcode = nullptr;
   size_t trap_opcode_size = 0;
 
@@ -1918,8 +1919,7 @@
   } break;
 
   default:
-    llvm_unreachable(
-        "Unhandled architecture in Platform::GetSoftwareBreakpointTrapOpcode");
+    return 0;
   }
 
   assert(bp_site);