[cling] fix error handling when parsing invaild code

llvm::Error need to be consumed before destructor

Author: Vipul-Cariappa

interpreter/cling/lib/Interpreter/IncrementalParser.cpp

@@ -53,6 +53,7 @@
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBuffer.h"
 
 #include <stdio.h>
@@ -911,8 +912,11 @@ namespace cling {
     PP.EnterSourceFile(FID, /*DirLookup*/nullptr, NewLoc);
     m_Consumer->getTransaction()->setBufferFID(FID);
 
-    if (!ParseOrWrapTopLevelDecl())
+    llvm::Error res = ParseOrWrapTopLevelDecl();
+    if (res) {
+      llvm::consumeError(std::move(res));
       return kFailed;
+    }
 
     if (PP.getLangOpts().DelayedTemplateParsing) {
       // Microsoft-specific:
@@ -939,7 +943,7 @@ namespace cling {
     return kSuccess;
   }
 
-  llvm::Expected<bool> IncrementalParser::ParseOrWrapTopLevelDecl() {
+  llvm::Error IncrementalParser::ParseOrWrapTopLevelDecl() {
     // Recover resources if we crash before exiting this method.
     Sema& S = getCI()->getSema();
     DiagnosticsEngine& Diags = getCI()->getDiagnostics();
@@ -993,7 +997,7 @@ namespace cling {
       // Let's ignore this transaction:
       m_Consumer->getTransaction()->setIssuedDiags(Transaction::kErrors);
 
-      return true;
+      return llvm::Error::success();
     }
 
     // Process any TopLevelDecls generated by #pragma weak.
@@ -1005,7 +1009,7 @@ namespace cling {
     LocalInstantiations.perform();
     GlobalInstantiations.perform();
 
-    return true;
+    return llvm::Error::success();
   }
 
   void IncrementalParser::printTransactionStructure() const {

interpreter/cling/lib/Interpreter/IncrementalParser.h

@@ -15,6 +15,7 @@
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
 
 #include <vector>
 #include <deque>
@@ -253,7 +254,7 @@ namespace cling {
     ///
     EParseResult ParseInternal(llvm::StringRef input);
 
-    llvm::Expected<bool> ParseOrWrapTopLevelDecl();
+    llvm::Error ParseOrWrapTopLevelDecl();
 
     ///\brief Create a unique name for the next llvm::Module
     ///