From 0f5c5dcf3eae75eb0ba92b8687a2f20d4581319d Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 16 Mar 2026 16:42:30 +0100
Subject: [PATCH] Fix memory issues on Web

---
 Source/Engine/Platform/Unix/UnixPlatform.h            |  1 -
 Source/Engine/Platform/Web/WebPlatform.cpp            | 11 +----------
 Source/Engine/Platform/Web/WebPlatform.h              |  5 ++++-
 Source/Engine/Serialization/Json.h                    |  2 +-
 Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs | 11 +++++++++--
 5 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/Source/Engine/Platform/Unix/UnixPlatform.h b/Source/Engine/Platform/Unix/UnixPlatform.h
index d0f5ce481..f393b5914 100644
--- a/Source/Engine/Platform/Unix/UnixPlatform.h
+++ b/Source/Engine/Platform/Unix/UnixPlatform.h
@@ -12,7 +12,6 @@
 class FLAXENGINE_API UnixPlatform : public PlatformBase
 {
 public:
-    
     // [PlatformBase]
     static void* Allocate(uint64 size, uint64 alignment);
     static void Free(void* ptr);
diff --git a/Source/Engine/Platform/Web/WebPlatform.cpp b/Source/Engine/Platform/Web/WebPlatform.cpp
index 6470a26f7..9967dd93f 100644
--- a/Source/Engine/Platform/Web/WebPlatform.cpp
+++ b/Source/Engine/Platform/Web/WebPlatform.cpp
@@ -179,15 +179,6 @@ void WebPlatform::Log(const StringView& msg, int32 logType)
     emscripten_log(flags, buffer);
 }
 
-#if !BUILD_RELEASE
-
-bool WebPlatform::IsDebuggerPresent()
-{
-    return false;
-}
-
-#endif
-
 String WebPlatform::GetComputerName()
 {
     return TEXT("Web");
@@ -335,7 +326,7 @@ Array<PlatformBase::StackFrame> WebPlatform::GetStackFrames(int32 skipCount, int
     Array<StackFrame> result;
 #if CRASH_LOG_ENABLE
     // Get callstack
-    char callstack[1024];
+    char callstack[2000];
     emscripten_get_callstack(EM_LOG_JS_STACK, callstack, sizeof(callstack));
 
     // Parse callstack
diff --git a/Source/Engine/Platform/Web/WebPlatform.h b/Source/Engine/Platform/Web/WebPlatform.h
index 83d6f0e15..4a6b85ac9 100644
--- a/Source/Engine/Platform/Web/WebPlatform.h
+++ b/Source/Engine/Platform/Web/WebPlatform.h
@@ -111,7 +111,10 @@ public:
     static void GetUTCTime(int32& year, int32& month, int32& dayOfWeek, int32& day, int32& hour, int32& minute, int32& second, int32& millisecond);
     static void Log(const StringView& msg, int32 logType = 1);
 #if !BUILD_RELEASE
-    static bool IsDebuggerPresent();
+    static bool IsDebuggerPresent()
+    {
+        return false;
+    }
 #endif
     static String GetComputerName();
     static bool GetHasFocus();
diff --git a/Source/Engine/Serialization/Json.h b/Source/Engine/Serialization/Json.h
index 6f300f3ae..1823935e5 100644
--- a/Source/Engine/Serialization/Json.h
+++ b/Source/Engine/Serialization/Json.h
@@ -5,7 +5,7 @@
 #include "Engine/Core/Types/String.h"
 #include "Engine/Core/Types/StringView.h"
 
-#if PLATFORM_WEB
+#if PLATFORM_WEB && PLATFORM_SIMD_SSE2
 #define RAPIDJSON_SSE2
 #elif PLATFORM_SIMD_SSE4_2
 #define RAPIDJSON_SSE42
diff --git a/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs b/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
index 26eb039d1..c3e8f7749 100644
--- a/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
+++ b/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
@@ -169,8 +169,10 @@ namespace Flax.Build.Platforms
                 args.Add("-fsanitize=address");
             if (sanitizers.HasFlag(Sanitizer.Undefined))
                 args.Add("-fsanitize=undefined");
-            if (sanitizers == Sanitizer.None)
-                args.Add("-fsanitize=null -fsanitize-minimal-runtime"); // Minimal Runtime
+            //if (sanitizers == Sanitizer.None && options.Configuration != TargetConfiguration.Release)
+            //    args.Add("-fsanitize=null -fsanitize-minimal-runtime"); // Minimal Runtime
+            if (sanitizers == Sanitizer.None) // TODO: fix random memory issues around malloc (eg. when resizing canvas) that are not happening when using Address sanitizer (wierd)
+                args.Add("-fsanitize=address");
 
             if (Configuration.WebThreads)
                 args.Add("-pthread");
@@ -289,7 +291,12 @@ namespace Flax.Build.Platforms
                     initialMemory = Math.Max(initialMemory, 64); // Address Sanitizer needs more memory
                 args.Add($"-sINITIAL_MEMORY={initialMemory}MB");
                 args.Add("-sSTACK_SIZE=4MB");
+                args.Add("-sASYNCIFY_STACK_SIZE=8192");
                 args.Add("-sALLOW_MEMORY_GROWTH=1");
+                //args.Add("-sSAFE_HEAP=1");
+                args.Add("-sABORTING_MALLOC=0");
+                //args.Add("-sMALLOC=emmalloc-memvalidate");
+                //args.Add("-sMALLOC=emmalloc");
 
                 // Setup file access (Game Cooker packs files with file_packager tool)
                 args.Add("-sFORCE_FILESYSTEM");