Index: ps/trunk/source/scriptinterface/ScriptContext.cpp
===================================================================
--- ps/trunk/source/scriptinterface/ScriptContext.cpp	(revision 25279)
+++ ps/trunk/source/scriptinterface/ScriptContext.cpp	(revision 25280)
@@ -1,255 +1,265 @@
 /* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * 0 A.D. is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include "precompiled.h"
 
 #include "ScriptContext.h"
 
+#include "lib/alignment.h"
 #include "ps/GameSetup/Config.h"
 #include "ps/Profile.h"
 #include "scriptinterface/ScriptExtraHeaders.h"
 #include "scriptinterface/ScriptEngine.h"
 #include "scriptinterface/ScriptInterface.h"
 
 void GCSliceCallbackHook(JSContext* UNUSED(cx), JS::GCProgress progress, const JS::GCDescription& UNUSED(desc))
 {
 	/**
 	 * From the GCAPI.h file:
 	 * > During GC, the GC is bracketed by GC_CYCLE_BEGIN/END callbacks. Each
 	 * > slice between those (whether an incremental or the sole non-incremental
 	 * > slice) is bracketed by GC_SLICE_BEGIN/GC_SLICE_END.
 	 * Thus, to safely monitor GCs, we need to profile SLICE_X calls.
 	 */
 
 
 	if (progress == JS::GC_SLICE_BEGIN)
 	{
 		if (CProfileManager::IsInitialised() && Threading::IsMainThread())
 			g_Profiler.Start("GCSlice");
 		g_Profiler2.RecordRegionEnter("GCSlice");
 	}
 	else if (progress == JS::GC_SLICE_END)
 	{
 		if (CProfileManager::IsInitialised() && Threading::IsMainThread())
 			g_Profiler.Stop();
 		g_Profiler2.RecordRegionLeave();
 	}
 
 	// The following code can be used to print some information aobut garbage collection
 	// Search for "Nonincremental reason" if there are problems running GC incrementally.
 	#if 0
 	if (progress == JS::GCProgress::GC_CYCLE_BEGIN)
 		printf("starting cycle ===========================================\n");
 
 	const char16_t* str = desc.formatMessage(cx);
 	int len = 0;
 
 	for(int i = 0; i < 10000; i++)
 	{
 		len++;
 		if(!str[i])
 			break;
 	}
 
 	wchar_t outstring[len];
 
 	for(int i = 0; i < len; i++)
 	{
 		outstring[i] = (wchar_t)str[i];
 	}
 
 	printf("---------------------------------------\n: %ls \n---------------------------------------\n", outstring);
 	#endif
 }
 
 shared_ptr<ScriptContext> ScriptContext::CreateContext(int contextSize, int heapGrowthBytesGCTrigger)
 {
 	return std::make_shared<ScriptContext>(contextSize, heapGrowthBytesGCTrigger);
 }
 
 ScriptContext::ScriptContext(int contextSize, int heapGrowthBytesGCTrigger):
 	m_LastGCBytes(0),
 	m_LastGCCheck(0.0f),
 	m_HeapGrowthBytesGCTrigger(heapGrowthBytesGCTrigger),
 	m_ContextSize(contextSize)
 {
 	ENSURE(ScriptEngine::IsInitialised() && "The ScriptEngine must be initialized before constructing any ScriptContexts!");
 
 	m_cx = JS_NewContext(contextSize);
 	ENSURE(m_cx); // TODO: error handling
 
+	// Set stack quota limits - JS scripts will stop with a "too much recursion" exception.
+	// This seems to refer to the program's actual stack size, so it should be lower than the lowest common denominator
+	// of the various stack sizes of supported OS.
+	// From SM78's jsapi.h:
+	// - "The stack quotas for each kind of code should be monotonically descending"
+	// - "This function may only be called immediately after the runtime is initialized
+	//   and before any code is executed and/or interrupts requested"
+	JS_SetNativeStackQuota(m_cx, 950 * KiB, 900 * KiB, 850 * KiB);
+
 	ENSURE(JS::InitSelfHostedCode(m_cx));
 
 	JS::SetGCSliceCallback(m_cx, GCSliceCallbackHook);
 
 	JS_SetGCParameter(m_cx, JSGC_MAX_BYTES, m_ContextSize);
 	JS_SetGCParameter(m_cx, JSGC_MODE, JSGC_MODE_INCREMENTAL);
 
 	JS_SetOffthreadIonCompilationEnabled(m_cx, true);
 
 	// For GC debugging:
 	// JS_SetGCZeal(m_cx, 2, JS_DEFAULT_ZEAL_FREQ);
 
 	JS_SetContextPrivate(m_cx, nullptr);
 
 	JS_SetGlobalJitCompilerOption(m_cx, JSJITCOMPILER_ION_ENABLE, 1);
 	JS_SetGlobalJitCompilerOption(m_cx, JSJITCOMPILER_BASELINE_ENABLE, 1);
 
 	JS::ContextOptionsRef(m_cx).setStrictMode(true);
 
 	ScriptEngine::GetSingleton().RegisterContext(m_cx);
 }
 
 ScriptContext::~ScriptContext()
 {
 	ENSURE(ScriptEngine::IsInitialised() && "The ScriptEngine must be active (initialized and not yet shut down) when destroying a ScriptContext!");
 
 	JS_DestroyContext(m_cx);
 	ScriptEngine::GetSingleton().UnRegisterContext(m_cx);
 }
 
 void ScriptContext::RegisterRealm(JS::Realm* realm)
 {
 	ENSURE(realm);
 	m_Realms.push_back(realm);
 }
 
 void ScriptContext::UnRegisterRealm(JS::Realm* realm)
 {
 	// Schedule the zone for GC, which will destroy the realm.
 	if (JS::IsIncrementalGCInProgress(m_cx))
 		JS::FinishIncrementalGC(m_cx, JS::GCReason::API);
 	JS::PrepareZoneForGC(js::GetRealmZone(realm));
 	m_Realms.remove(realm);
 }
 
 #define GC_DEBUG_PRINT 0
 void ScriptContext::MaybeIncrementalGC(double delay)
 {
 	PROFILE2("MaybeIncrementalGC");
 
 	if (JS::IsIncrementalGCEnabled(m_cx))
 	{
 		// The idea is to get the heap size after a completed GC and trigger the next GC when the heap size has
 		// reached m_LastGCBytes + X.
 		// In practice it doesn't quite work like that. When the incremental marking is completed, the sweeping kicks in.
 		// The sweeping actually frees memory and it does this in a background thread (if JS_USE_HELPER_THREADS is set).
 		// While the sweeping is happening we already run scripts again and produce new garbage.
 
 		const int GCSliceTimeBudget = 30; // Milliseconds an incremental slice is allowed to run
 
 		// Have a minimum time in seconds to wait between GC slices and before starting a new GC to distribute the GC
 		// load and to hopefully make it unnoticeable for the player. This value should be high enough to distribute
 		// the load well enough and low enough to make sure we don't run out of memory before we can start with the
 		// sweeping.
 		if (timer_Time() - m_LastGCCheck < delay)
 			return;
 
 		m_LastGCCheck = timer_Time();
 
 		int gcBytes = JS_GetGCParameter(m_cx, JSGC_BYTES);
 
 #if GC_DEBUG_PRINT
 			std::cout << "gcBytes: " << gcBytes / 1024 << " KB" << std::endl;
 #endif
 
 		if (m_LastGCBytes > gcBytes || m_LastGCBytes == 0)
 		{
 #if GC_DEBUG_PRINT
 			printf("Setting m_LastGCBytes: %d KB \n", gcBytes / 1024);
 #endif
 			m_LastGCBytes = gcBytes;
 		}
 
 		// Run an additional incremental GC slice if the currently running incremental GC isn't over yet
 		// ... or
 		// start a new incremental GC if the JS heap size has grown enough for a GC to make sense
 		if (JS::IsIncrementalGCInProgress(m_cx) || (gcBytes - m_LastGCBytes > m_HeapGrowthBytesGCTrigger))
 		{
 #if GC_DEBUG_PRINT
 			if (JS::IsIncrementalGCInProgress(m_cx))
 				printf("An incremental GC cycle is in progress. \n");
 			else
 				printf("GC needed because JSGC_BYTES - m_LastGCBytes > m_HeapGrowthBytesGCTrigger \n"
 					"    JSGC_BYTES: %d KB \n    m_LastGCBytes: %d KB \n    m_HeapGrowthBytesGCTrigger: %d KB \n",
 					gcBytes / 1024,
 					m_LastGCBytes / 1024,
 					m_HeapGrowthBytesGCTrigger / 1024);
 #endif
 
 			// A hack to make sure we never exceed the context size because we can't collect the memory
 			// fast enough.
 			if (gcBytes > m_ContextSize / 2)
 			{
 				if (JS::IsIncrementalGCInProgress(m_cx))
 				{
 #if GC_DEBUG_PRINT
 					printf("Finishing incremental GC because gcBytes > m_ContextSize / 2. \n");
 #endif
 					PrepareZonesForIncrementalGC();
 					JS::FinishIncrementalGC(m_cx, JS::GCReason::API);
 				}
 				else
 				{
 					if (gcBytes > m_ContextSize * 0.75)
 					{
 						ShrinkingGC();
 #if GC_DEBUG_PRINT
 						printf("Running shrinking GC because gcBytes > m_ContextSize * 0.75. \n");
 #endif
 					}
 					else
 					{
 #if GC_DEBUG_PRINT
 						printf("Running full GC because gcBytes > m_ContextSize / 2. \n");
 #endif
 						JS_GC(m_cx);
 					}
 				}
 			}
 			else
 			{
 #if GC_DEBUG_PRINT
 				if (!JS::IsIncrementalGCInProgress(m_cx))
 					printf("Starting incremental GC \n");
 				else
 					printf("Running incremental GC slice \n");
 #endif
 				PrepareZonesForIncrementalGC();
 				if (!JS::IsIncrementalGCInProgress(m_cx))
 					JS::StartIncrementalGC(m_cx, GC_NORMAL, JS::GCReason::API, GCSliceTimeBudget);
 				else
 					JS::IncrementalGCSlice(m_cx, JS::GCReason::API, GCSliceTimeBudget);
 			}
 			m_LastGCBytes = gcBytes;
 		}
 	}
 }
 
 void ScriptContext::ShrinkingGC()
 {
 	JS_SetGCParameter(m_cx, JSGC_MODE, JSGC_MODE_ZONE);
 	JS::PrepareForFullGC(m_cx);
 	JS::NonIncrementalGC(m_cx, GC_SHRINK, JS::GCReason::API);
 	JS_SetGCParameter(m_cx, JSGC_MODE, JSGC_MODE_INCREMENTAL);
 }
 
 void ScriptContext::PrepareZonesForIncrementalGC() const
 {
 	for (JS::Realm* const& realm : m_Realms)
 		JS::PrepareZoneForGC(js::GetRealmZone(realm));
 }