[ArchSpec] Don't consider Unknown MachO64 as invalid.

Even without a proper arch we can access line tables, etc..

<rdar://problem/35778442>

llvm-svn: 321856

1 files changed, 6 insertions, 1 deletions

diff --git a/lldb/source/Utility/ArchSpec.cpp b/lldb/source/Utility/ArchSpec.cpp
index a10fe78260b..ed236f5f641 100644
--- a/lldb/source/Utility/ArchSpec.cpp
+++ b/lldb/source/Utility/ArchSpec.cpp
@@ -890,7 +890,12 @@ void ArchSpec::MergeFrom(const ArchSpec &other) {
     GetTriple().setOS(other.GetTriple().getOS());
   if (GetTriple().getArch() == llvm::Triple::UnknownArch) {
     GetTriple().setArch(other.GetTriple().getArch());
-    UpdateCore();
+
+    // MachO unknown64 isn't really invalid as the debugger can
+    // still obtain information from the binary, e.g. line tables.
+    // As such, we don't update the core here.
+    if (other.GetCore() != eCore_uknownMach64)
+      UpdateCore();
   }
   if (GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment &&
       !TripleVendorWasSpecified()) {