Reland "[clang-repl] Adapt to the recent dylib-related changes in ORC."

Original commit message:"

ORC splits into separate dylibs symbols coming from the process and symbols
materialized in the Jit. This patch adapts intent of the existing interface and
adds a regression test to make sure both Jit'd and compiled symbols can be found.

Differential revision: https://reviews.llvm.org/D159115
"

This patch disables the test statement on windows as it seems we might have a
bug in the way we model dllimports.

(cherry picked from commit 452cb7f)

clang/lib/Interpreter/IncrementalExecutor.cpp

@@ -92,12 +92,19 @@ llvm::Error IncrementalExecutor::runCtors() const {
 llvm::Expected<llvm::orc::ExecutorAddr>
 IncrementalExecutor::getSymbolAddress(llvm::StringRef Name,
                                       SymbolNameKind NameKind) const {
-  auto Sym = (NameKind == LinkerName) ? Jit->lookupLinkerMangled(Name)
-                                      : Jit->lookup(Name);
-
-  if (!Sym)
-    return Sym.takeError();
-  return Sym;
+  using namespace llvm::orc;
+  auto SO = makeJITDylibSearchOrder({&Jit->getMainJITDylib(),
+                                     Jit->getPlatformJITDylib().get(),
+                                     Jit->getProcessSymbolsJITDylib().get()});
+
+  ExecutionSession &ES = Jit->getExecutionSession();
+
+  auto SymOrErr =
+      ES.lookup(SO, (NameKind == LinkerName) ? ES.intern(Name)
+                                             : Jit->mangleAndIntern(Name));
+  if (auto Err = SymOrErr.takeError())
+    return std::move(Err);
+  return SymOrErr->getAddress();
 }
 
 } // end namespace clang

clang/unittests/Interpreter/InterpreterTest.cpp

@@ -232,10 +232,20 @@ TEST(IncrementalProcessing, FindMangledNameSymbol) {
   }
 
   std::string MangledName = MangleName(FD);
-  auto Addr = cantFail(Interp->getSymbolAddress(MangledName));
-  EXPECT_NE(0U, Addr.getValue());
+  auto Addr = Interp->getSymbolAddress(MangledName);
+  EXPECT_FALSE(!Addr);
+  EXPECT_NE(0U, Addr->getValue());
   GlobalDecl GD(FD);
-  EXPECT_EQ(Addr, cantFail(Interp->getSymbolAddress(GD)));
+  EXPECT_EQ(*Addr, cantFail(Interp->getSymbolAddress(GD)));
+  cantFail(
+      Interp->ParseAndExecute("extern \"C\" int printf(const char*,...);"));
+  Addr = Interp->getSymbolAddress("printf");
+  EXPECT_FALSE(!Addr);
+
+  // FIXME: Re-enable when we investigate the way we handle dllimports on Win.
+#ifndef _WIN32
+  EXPECT_EQ((unsigned long long)&printf, Addr->getValue());
+#endif // _WIN32
 }
 
 static void *AllocateObject(TypeDecl *TD, Interpreter &Interp) {