Fix failure to initialize stack nested func parent pointer. When a fully compiled function is nested inside a redeferred function, we can quit byte code generation early for the nested function. But don't do so until its stack nested function parent pointer has been initialized (if necessary).

pleath · pleath · commit 54a31c66694e · 2017-02-23T11:53:24.000-08:00
diff --git a/lib/Runtime/ByteCode/ByteCodeEmitter.cpp b/lib/Runtime/ByteCode/ByteCodeEmitter.cpp
@@ -3008,14 +3008,43 @@ void ByteCodeGenerator::EmitOneFunction(ParseNode *pnode)
     // so they have pointers to the stub sub-trees they need.)
     byteCodeFunction->SetDeferredStubs(nullptr);
 
-    if (byteCodeFunction->GetByteCode() != nullptr)
-    {
-        // Previously compiled function nested within a re-deferred and re-compiled function.
-        return;
-    }
-
     try
     {
+        if (!funcInfo->IsGlobalFunction())
+        {
+            // Note: Do not set the stack nested func flag if the function has been redeferred and recompiled.
+            // In that case the flag already has the value we want.
+            if (CanStackNestedFunc(funcInfo, true) && byteCodeFunction->GetCompileCount() == 0)
+            {
+#if DBG
+                byteCodeFunction->SetCanDoStackNestedFunc();
+#endif
+                if (funcInfo->root->sxFnc.astSize <= PnFnc::MaxStackClosureAST)
+                {
+                    byteCodeFunction->SetStackNestedFunc(true);
+                }
+            }
+        }
+
+        if (byteCodeFunction->DoStackNestedFunc())
+        {
+            uint nestedCount = byteCodeFunction->GetNestedCount();
+            for (uint i = 0; i < nestedCount; i++)
+            {
+                Js::FunctionProxy * nested = byteCodeFunction->GetNestedFunctionProxy(i);
+                if (nested->IsFunctionBody())
+                {
+                    nested->GetFunctionBody()->SetStackNestedFuncParent(byteCodeFunction->GetFunctionInfo());
+                }
+            }
+        }
+
+        if (byteCodeFunction->GetByteCode() != nullptr)
+        {
+            // Previously compiled function nested within a re-deferred and re-compiled function.
+            return;
+        }
+
         // Bug : 301517
         // In the debug mode the hasOnlyThis optimization needs to be disabled, since user can break in this function
         // and do operation on 'this' and its property, which may not be defined yet.
@@ -3059,22 +3088,6 @@ void ByteCodeGenerator::EmitOneFunction(ParseNode *pnode)
             }
         }
 
-        if (!funcInfo->IsGlobalFunction())
-        {
-            // Note: Do not set the stack nested func flag if the function has been redeferred and recompiled.
-            // In that case the flag already has the value we want.
-            if (CanStackNestedFunc(funcInfo, true) && byteCodeFunction->GetCompileCount() == 0)
-            {
-#if DBG
-                byteCodeFunction->SetCanDoStackNestedFunc();
-#endif
-                if (funcInfo->root->sxFnc.astSize <= PnFnc::MaxStackClosureAST)
-                {
-                    byteCodeFunction->SetStackNestedFunc(true);
-                }
-            }
-        }
-
         InitScopeSlotArray(funcInfo);
         FinalizeRegisters(funcInfo, byteCodeFunction);
         DebugOnly(Js::RegSlot firstTmpReg = funcInfo->varRegsCount);
@@ -3238,19 +3251,6 @@ void ByteCodeGenerator::EmitOneFunction(ParseNode *pnode)
             }
         }
 
-        if (byteCodeFunction->DoStackNestedFunc())
-        {
-            uint nestedCount = byteCodeFunction->GetNestedCount();
-            for (uint i = 0; i < nestedCount; i++)
-            {
-                Js::FunctionProxy * nested = byteCodeFunction->GetNestedFunctionProxy(i);
-                if (nested->IsFunctionBody())
-                {
-                    nested->GetFunctionBody()->SetStackNestedFuncParent(byteCodeFunction->GetFunctionInfo());
-                }
-            }
-        }
-
         if (funcInfo->IsGlobalFunction())
         {
             EnsureNoRedeclarations(pnode->sxFnc.pnodeScopes, funcInfo);
