QuickJS: bound the JS stack to the thread's real stack; Chakra: define globalThis

Core/AppRuntime/Source/AppRuntime_QuickJS.cpp

@@ -18,37 +18,110 @@
 #pragma warning(pop)
 #endif
 
+#include <stdexcept>
+#include <cstddef>
+
+#if defined(__ANDROID__)
+#include <pthread.h>
+#include <exception>
+#include <functional>
+#include <utility>
+#endif
+
 namespace Babylon
 {
-    void AppRuntime::RunEnvironmentTier(const char* /*executablePath*/)
+    namespace
     {
-        // Create the runtime.
-        JSRuntime* runtime = JS_NewRuntime();
-        if (!runtime)
+        // Runs the QuickJS environment on the calling thread. QuickJS's interpreter recurses in C
+        // (one JS_CallInternal frame per JS call), so deep JS call stacks need a comparably deep C
+        // stack; QuickJS's own limit (JS_DEFAULT_STACK_SIZE, 1 MiB) guards against overrun.
+        // jsStackLimit: value for JS_SetMaxStackSize, or 0 to keep QuickJS's default (1 MiB). A
+        // non-default limit is only safe when the caller guarantees a stack large enough to hold it
+        // below the guard page -- see the Android nested-thread path below.
+        void RunQuickJSEnvironment(AppRuntime& appRuntime, void (AppRuntime::*run)(Napi::Env), size_t jsStackLimit)
         {
-            throw std::runtime_error{"Failed to create QuickJS runtime"};
-        }
+            JSRuntime* runtime = JS_NewRuntime();
+            if (!runtime)
+            {
+                throw std::runtime_error{"Failed to create QuickJS runtime"};
+            }
+            if (jsStackLimit != 0)
+            {
+                JS_SetMaxStackSize(runtime, jsStackLimit);
+            }
 
-        // Create the context.
-        JSContext* context = JS_NewContext(runtime);
-        if (!context)
-        {
+            JSContext* context = JS_NewContext(runtime);
+            if (!context)
+            {
+                JS_FreeRuntime(runtime);
+                throw std::runtime_error{"Failed to create QuickJS context"};
+            }
+
+            {
+                Napi::Env env = Napi::Attach(context);
+                (appRuntime.*run)(env);
+                Napi::Detach(env);
+            }
+
+            JS_FreeContext(context);
             JS_FreeRuntime(runtime);
-            throw std::runtime_error{"Failed to create QuickJS context"};
         }
+    }
 
-        // Use the context within a scope.
-        {
-            Napi::Env env = Napi::Attach(context);
-
-            Run(env);
+    void AppRuntime::RunEnvironmentTier(const char* /*executablePath*/)
+    {
+#if defined(__ANDROID__)
+        // bionic gives this worker thread ~1 MiB of stack, at or below QuickJS's default 1 MiB
+        // recursion limit -- so deep-but-legal JS recursion faults the guard page (SIGSEGV) before
+        // QuickJS can raise a catchable "stack overflow", while clamping the limit below 1 MiB
+        // instead rejects call depths that every other engine (and desktop QuickJS on its ~8 MiB
+        // stack) accepts. Run the environment on a nested thread with a desktop-sized stack so
+        // QuickJS's raised limit sits safely below the guard page and deep recursion fits. The
+        // stack must be generous because connectedAndroidTest is an unoptimized Debug build, whose
+        // JS_CallInternal frames are several times larger than a release build's -- depth-128
+        // recursion (which release QuickJS clears within the 1 MiB default) needs well over 1 MiB
+        // here, so QuickJS's default limit would still reject it on any thread size.
+        constexpr size_t NestedStackSize{8 * 1024 * 1024};
+        constexpr size_t JsStackLimit{6 * 1024 * 1024}; // < NestedStackSize guard; > debug depth-128 need
+        std::function<void()> body{[this] { RunQuickJSEnvironment(*this, &AppRuntime::Run, JsStackLimit); }};
+        std::exception_ptr thrown{};
+        auto payload = std::make_pair(&body, &thrown);
+        auto trampoline = [](void* arg) -> void* {
+            auto* p = static_cast<std::pair<std::function<void()>*, std::exception_ptr*>*>(arg);
+            try
+            {
+                (*p->first)();
+            }
+            catch (...)
+            {
+                *p->second = std::current_exception();
+            }
+            return nullptr;
+        };
 
-            Napi::Detach(env);
+        pthread_attr_t attr;
+        if (pthread_attr_init(&attr) == 0)
+        {
+            pthread_attr_setstacksize(&attr, NestedStackSize);
+            pthread_t tid{};
+            const int created = pthread_create(&tid, &attr, trampoline, &payload);
+            pthread_attr_destroy(&attr);
+            if (created == 0)
+            {
+                pthread_join(tid, nullptr);
+                if (thrown)
+                {
+                    std::rethrow_exception(thrown);
+                }
+                return;
+            }
         }
-
-        // Destroy the context and runtime.
-        JS_FreeContext(context);
-        JS_FreeRuntime(runtime);
+        // Thread creation failed: fall back to the current (small) worker thread, where only
+        // QuickJS's default limit is safe.
+        RunQuickJSEnvironment(*this, &AppRuntime::Run, 0);
+#else
+        RunQuickJSEnvironment(*this, &AppRuntime::Run, 0);
+#endif
     }
 
     void AppRuntime::ShutdownEnvironment(Napi::Env)

Core/Node-API/Source/env_chakra.cc

@@ -23,6 +23,37 @@ namespace Napi
         JsValueRef global;
         ThrowIfFailed(JsGetGlobalObject(&global));
         JsPropertyIdRef propertyId;
+
+        // The Windows 10 Chakra predates ES2020 and has no `globalThis`; scripts written against
+        // browsers (and the polyfills in this repo) reference it. Define it as a plain, writable,
+        // configurable property of the global object, exactly as the spec describes.
+        ThrowIfFailed(JsGetPropertyIdFromName(L"globalThis", &propertyId));
+        JsValueRef existingGlobalThis;
+        ThrowIfFailed(JsGetProperty(global, propertyId, &existingGlobalThis));
+        JsValueType existingType;
+        ThrowIfFailed(JsGetValueType(existingGlobalThis, &existingType));
+        if (existingType == JsUndefined)
+        {
+            // { value: globalThis, writable: true, enumerable: false, configurable: true } -- the
+            // spec's own data property; plain assignment would make it enumerable.
+            JsValueRef descriptor;
+            ThrowIfFailed(JsCreateObject(&descriptor));
+            JsValueRef trueValue;
+            ThrowIfFailed(JsGetTrueValue(&trueValue));
+            JsValueRef falseValue;
+            ThrowIfFailed(JsGetFalseValue(&falseValue));
+            JsPropertyIdRef descriptorPropertyId;
+            ThrowIfFailed(JsGetPropertyIdFromName(L"value", &descriptorPropertyId));
+            ThrowIfFailed(JsSetProperty(descriptor, descriptorPropertyId, global, true));
+            ThrowIfFailed(JsGetPropertyIdFromName(L"writable", &descriptorPropertyId));
+            ThrowIfFailed(JsSetProperty(descriptor, descriptorPropertyId, trueValue, true));
+            ThrowIfFailed(JsGetPropertyIdFromName(L"enumerable", &descriptorPropertyId));
+            ThrowIfFailed(JsSetProperty(descriptor, descriptorPropertyId, falseValue, true));
+            ThrowIfFailed(JsGetPropertyIdFromName(L"configurable", &descriptorPropertyId));
+            ThrowIfFailed(JsSetProperty(descriptor, descriptorPropertyId, trueValue, true));
+            bool defined;
+            ThrowIfFailed(JsDefineProperty(global, propertyId, descriptor, &defined));
+        }
         ThrowIfFailed(JsGetPropertyIdFromName(L"Object", &propertyId));
         JsValueRef object;
         ThrowIfFailed(JsGetProperty(global, propertyId, &object));