From 02e36978171e99eafa9f906bd03b4b1ee9a17638 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Fri, 20 Jan 2023 15:42:32 +0100
Subject: [PATCH] Fix using proper engine native module for importing symbols

---
 Source/Engine/Scripting/ManagedCLR/MCore.cpp  |  9 +++++++--
 Source/Engine/Scripting/Scripting.Build.cs    | 11 +++++++++++
 Source/Tools/Flax.Build/Build/EngineTarget.cs |  5 ++++-
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Source/Engine/Scripting/ManagedCLR/MCore.cpp b/Source/Engine/Scripting/ManagedCLR/MCore.cpp
index 89384b342..d65c04a0e 100644
--- a/Source/Engine/Scripting/ManagedCLR/MCore.cpp
+++ b/Source/Engine/Scripting/ManagedCLR/MCore.cpp
@@ -135,9 +135,14 @@ bool MCore::LoadEngine()
         return false;
 
     // Prepare managed side
-    const StringAnsi hostExecutable(Platform::GetExecutableFilePath());
     CoreCLR::CallStaticMethodByName<void>(TEXT("Init"));
-    CoreCLR::RegisterNativeLibrary("FlaxEngine", hostExecutable.Get());
+#ifdef MCORE_MAIN_MODULE_NAME
+    // MCORE_MAIN_MODULE_NAME define is injected by Scripting.Build.cs on platforms that use separate shared library for engine symbols
+    const StringAnsi flaxLibraryPath(Platform::GetMainDirectory() / TEXT(MACRO_TO_STR(MCORE_MAIN_MODULE_NAME)));
+#else
+    const StringAnsi flaxLibraryPath(Platform::GetExecutableFilePath());
+#endif
+    CoreCLR::RegisterNativeLibrary("FlaxEngine", flaxLibraryPath.Get());
 
     MRootDomain = New<MDomain>("Root");
     MDomains.Add(MRootDomain);
diff --git a/Source/Engine/Scripting/Scripting.Build.cs b/Source/Engine/Scripting/Scripting.Build.cs
index 284210854..2fd4b54df 100644
--- a/Source/Engine/Scripting/Scripting.Build.cs
+++ b/Source/Engine/Scripting/Scripting.Build.cs
@@ -16,9 +16,20 @@ public class Scripting : EngineModule
         if (EngineConfiguration.WithCSharp(options))
         {
             if (EngineConfiguration.WithDotNet(options))
+            {
                 options.PublicDependencies.Add("nethost");
+
+                if (options.Target is EngineTarget engineTarget && engineTarget.UseSeparateMainExecutable(options))
+                {
+                    // Build target doesn't support linking again main executable (eg. Linux) thus additional shared library is used for the engine (eg. libFlaxEditor.so)
+                    var fileName = options.Platform.GetLinkOutputFileName(engineTarget.OutputName, LinkerOutput.SharedLibrary);
+                    options.CompileEnv.PreprocessorDefinitions.Add("MCORE_MAIN_MODULE_NAME=" + fileName);
+                }
+            }
             else
+            {
                 options.PublicDependencies.Add("mono");
+            }
         }
 
         options.PrivateDependencies.Add("Utilities");
diff --git a/Source/Tools/Flax.Build/Build/EngineTarget.cs b/Source/Tools/Flax.Build/Build/EngineTarget.cs
index 0a6c6b1d1..e673e77e3 100644
--- a/Source/Tools/Flax.Build/Build/EngineTarget.cs
+++ b/Source/Tools/Flax.Build/Build/EngineTarget.cs
@@ -125,7 +125,10 @@ namespace Flax.Build
 #endif
         }
 
-        private bool UseSeparateMainExecutable(BuildOptions buildOptions)
+        /// <summary>
+        /// Returns true if this build target should use separate (aka main-only) executable file and separate runtime (in shared library). Used on platforms that don't support linking again executable file but only shared library (see HasExecutableFileReferenceSupport).
+        /// </summary>
+        public bool UseSeparateMainExecutable(BuildOptions buildOptions)
         {
             return UseSymbolsExports && OutputType == TargetOutputType.Executable && !buildOptions.Platform.HasExecutableFileReferenceSupport && !Configuration.BuildBindingsOnly;
         }