Fix embedding: NoRuntime atexit guard + redirectable cling::outs()

include/cling/Utils/Output.h

@@ -17,9 +17,13 @@
 namespace cling {
   namespace utils {
     ///\brief The 'stdout' stream. llvm::raw_ostream wrapper of std::cout
-    ///
+    /// Can be redirected via setOuts().
     llvm::raw_ostream& outs();
 
+    ///\brief Redirect cling::outs() to a custom stream.
+    /// Pass nullptr to restore the default (std::cout).
+    void setOuts(llvm::raw_ostream* s);
+
     ///\brief The 'stderr' stream. llvm::raw_ostream wrapper of std::cerr
     ///
     llvm::raw_ostream& errs();
@@ -69,6 +73,7 @@ namespace cling {
     typedef outstring<0>    stdstrstream;
   }
   using utils::outs;
+  using utils::setOuts;
   using utils::errs;
   using utils::log;
 

lib/Interpreter/Interpreter.cpp

@@ -450,6 +450,7 @@ namespace cling {
       }
     }
 
+    if (!NoRuntime) {
     // Intercept all atexit calls, as the Interpreter and functions will be long
     // gone when the -native- versions invoke them.
 #if defined(__GLIBC__)
@@ -533,6 +534,7 @@ namespace cling {
       Strm << ";\n";
 #endif
 #endif
+    } // !NoRuntime (atexit interception)
 
     if (!SyntaxOnly) {
       // Override the helper symbols injected by GenericLLVMIRPlatformSupport,

lib/Utils/Output.cpp

@@ -17,14 +17,22 @@
 
 namespace cling {
   namespace utils {
+    static llvm::raw_ostream* sOutOverride = nullptr;
+
     llvm::raw_ostream& outs() {
+      if (sOutOverride)
+        return *sOutOverride;
       static llvm::raw_os_ostream sOut(std::cout);
       sOut.SetUnbuffered();
       if (llvm::sys::Process::StandardOutIsDisplayed())
         sOut.enable_colors(true);
       return sOut;
     }
 
+    void setOuts(llvm::raw_ostream* s) {
+      sOutOverride = s;
+    }
+
     llvm::raw_ostream& errs() {
       static llvm::raw_os_ostream sErr(std::cerr);
       sErr.SetUnbuffered();