REPL: Don't call global_ctors before each entry.

The REPL was accreting global_ctors and rerunning all global initializers ever registered before every entry. Change it so that it only runs global initializers once and so that the ObjC initialization stuff that needs to happen on a per-entry basis just gets dropped directly into the main() for each entry.

Swift SVN r4154

tools/swift/Immediate.cpp

@@ -761,6 +761,7 @@ class REPLEnvironment {
   TranslationUnit *TU;
   llvm::SmallPtrSet<TranslationUnit*, 8> ImportedModules;
   SmallVector<llvm::Function*, 8> InitFns;
+  bool RanGlobalInitializers;
   llvm::LLVMContext LLVMContext;
   llvm::Module Module;
   llvm::Module DumpModule;
@@ -786,8 +787,8 @@ class REPLEnvironment {
     // Parse the current line(s).
     unsigned BufferOffset = 0;
     bool ShouldRun =
-    swift::appendToMainTranslationUnit(TU, BufferID, CurTUElem,
-                                       BufferOffset, Line.size());
+      swift::appendToMainTranslationUnit(TU, BufferID, CurTUElem,
+                                         BufferOffset, Line.size());
     
     if (Context.hadError()) {
       Context.Diags.resetHadAnyError();
@@ -847,7 +848,10 @@ class REPLEnvironment {
     
     // FIXME: The way we do this is really ugly... we should be able to
     // improve this.
-    EE->runStaticConstructorsDestructors(&Module, false);
+    if (!RanGlobalInitializers) {
+      EE->runStaticConstructorsDestructors(&Module, false);
+      RanGlobalInitializers = true;
+    }
     llvm::Function *EntryFn = Module.getFunction("main");
     EE->runFunctionAsMain(EntryFn, std::vector<std::string>(), 0);
     EE->freeMachineCodeForFunction(EntryFn);
@@ -866,6 +870,7 @@ public:
                                        Comp, Context,
                                        /*IsMainModule=*/true,
                                        /*IsReplModule=*/true)),
+      RanGlobalInitializers(false),
       Module("REPL", LLVMContext),
       DumpModule("REPL", LLVMContext),
       CurTUElem(0),