[Symbol] Use llvm::Expected when getting TypeSystems

Summary:
This commit achieves the following:
- Functions used to return a `TypeSystem *` return an
  `llvm::Expected<TypeSystem *>` now. This means that the result of a call
  is always checked, forcing clients to move more carefully.
- `TypeSystemMap::GetTypeSystemForLanguage` will either return an Error or a
  non-null pointer to a TypeSystem.

Reviewers: JDevlieghere, davide, compnerd

Subscribers: jdoerfert, lldb-commits

Differential Revision: https://reviews.llvm.org/D65122

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@367360 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 8 deletions

diff --git a/source/Plugins/Language/ObjC/CoreMedia.cpp b/source/Plugins/Language/ObjC/CoreMedia.cpp
index d19290ec5..247429da1 100644
--- a/source/Plugins/Language/ObjC/CoreMedia.cpp
+++ b/source/Plugins/Language/ObjC/CoreMedia.cpp
@@ -10,6 +10,7 @@
 #include "CoreMedia.h"
 
 #include "lldb/Utility/Flags.h"
+#include "lldb/Utility/Log.h"
 
 #include "lldb/Symbol/TypeSystem.h"
 #include "lldb/Target/Target.h"
@@ -25,18 +26,21 @@ bool lldb_private::formatters::CMTimeSummaryProvider(
   if (!type.IsValid())
     return false;
 
-  TypeSystem *type_system =
+  auto type_system_or_err =
       valobj.GetExecutionContextRef()
           .GetTargetSP()
-          ->GetScratchTypeSystemForLanguage(nullptr, lldb::eLanguageTypeC);
-  if (!type_system)
+          ->GetScratchTypeSystemForLanguage(lldb::eLanguageTypeC);
+  if (auto err = type_system_or_err.takeError()) {
+    LLDB_LOG_ERROR(
+        lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS),
+        std::move(err), "Failed to get scratch type system");
     return false;
-
+  }
   // fetch children by offset to compensate for potential lack of debug info
-  auto int64_ty =
-      type_system->GetBuiltinTypeForEncodingAndBitSize(eEncodingSint, 64);
-  auto int32_ty =
-      type_system->GetBuiltinTypeForEncodingAndBitSize(eEncodingSint, 32);
+  auto int64_ty = type_system_or_err->GetBuiltinTypeForEncodingAndBitSize(
+      eEncodingSint, 64);
+  auto int32_ty = type_system_or_err->GetBuiltinTypeForEncodingAndBitSize(
+      eEncodingSint, 32);
 
   auto value_sp(valobj.GetSyntheticChildAtOffset(0, int64_ty, true));
   auto timescale_sp(valobj.GetSyntheticChildAtOffset(8, int32_ty, true));