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Fix crash on Clang-platforms when calling base method from overriden scripting method (C# or Visual Script)

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This commit is contained in:
Wojtek Figat
2022-12-28 16:28:50 +01:00
parent 762f460e23
commit 7859e64db1
3 changed files with 66 additions and 27 deletions
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24
Source/Engine/Scripting/InternalCalls.h
View File

@@ -7,6 +7,30 @@
#include "ScriptingType.h"
#include "Types.h"
#if defined(__clang__)
// Helper utility to override vtable entry with automatic restore
// See BindingsGenerator.Cpp.cs that generates virtuall method wrappers for scripting to properly call overriden base method
struct FLAXENGINE_API VTableFunctionInjector
{
void** VTableAddr;
void* OriginalValue;
VTableFunctionInjector(void* object, void* originalFunc, void* func)
{
void** vtable = *(void***)object;
const int32 vtableIndex = GetVTableIndex(vtable, 200, originalFunc);
VTableAddr = vtable + vtableIndex;
OriginalValue = *VTableAddr;
*VTableAddr = func;
}
~VTableFunctionInjector()
{
*VTableAddr = OriginalValue;
}
};
#endif
#if USE_MONO
extern "C" FLAXENGINE_API void mono_add_internal_call(const char* name, const void* method);

55
Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs
View File

@@ -237,6 +237,41 @@ namespace Flax.Build.Bindings
return $"({typeInfo}){value}";
}
public static void GenerateCppVirtualWrapperCallBaseMethod(BuildData buildData, StringBuilder contents, VirtualClassInfo classInfo, FunctionInfo functionInfo, string scriptVTableBase, string scriptVTableOffset)
{
contents.AppendLine(" // Prevent stack overflow by calling native base method");
if (buildData.Toolchain is Platforms.UnixToolchain)
{
// Clang compiler
// TODO: secure VTableFunctionInjector with mutex (even at cost of performance)
contents.AppendLine($" {functionInfo.UniqueName}_Signature funcPtr = &{classInfo.NativeName}::{functionInfo.Name};");
contents.AppendLine($" VTableFunctionInjector vtableInjector(object, *(void**)&funcPtr, {scriptVTableBase}[{scriptVTableOffset} + 2]); // TODO: this is not thread-safe");
if (classInfo is InterfaceInfo)
{
contents.Append($" return (({classInfo.NativeName}*)(void*)object)->{functionInfo.Name}(");
}
else
{
contents.Append(" return (object->*funcPtr)(");
}
}
else
{
// MSVC or other compiler
contents.Append($" return (this->**({functionInfo.UniqueName}_Internal_Signature*)&{scriptVTableBase}[{scriptVTableOffset} + 2])(");
}
bool separator = false;
for (var i = 0; i < functionInfo.Parameters.Count; i++)
{
var parameterInfo = functionInfo.Parameters[i];
if (separator)
contents.Append(", ");
separator = true;
contents.Append(parameterInfo.Name);
}
contents.AppendLine(");");
}
private static string GenerateCppGetNativeClass(BuildData buildData, TypeInfo typeInfo, ApiTypeInfo caller, FunctionInfo functionInfo)
{
// Optimal path for in-build types
@@ -1198,19 +1233,7 @@ namespace Flax.Build.Bindings
contents.AppendLine(" if (WrapperCallInstance == object)");
contents.AppendLine(" {");
contents.AppendLine(" // Prevent stack overflow by calling native base method");
contents.AppendLine(" const auto scriptVTableBase = managedTypePtr->Script.ScriptVTableBase;");
contents.Append($" return (this->**({functionInfo.UniqueName}_Internal_Signature*)&scriptVTableBase[{scriptVTableOffset} + 2])(");
separator = false;
for (var i = 0; i < functionInfo.Parameters.Count; i++)
{
var parameterInfo = functionInfo.Parameters[i];
if (separator)
contents.Append(", ");
separator = true;
contents.Append(parameterInfo.Name);
}
contents.AppendLine(");");
GenerateCppVirtualWrapperCallBaseMethod(buildData, contents, classInfo, functionInfo, "managedTypePtr->Script.ScriptVTableBase", scriptVTableOffset);
contents.AppendLine(" }");
contents.AppendLine(" auto scriptVTable = (MMethod**)managedTypePtr->Script.ScriptVTable;");
contents.AppendLine($" ASSERT(scriptVTable && scriptVTable[{scriptVTableOffset}]);");
@@ -1327,7 +1350,11 @@ namespace Flax.Build.Bindings
}
var t = functionInfo.IsConst ? " const" : string.Empty;
contents.AppendLine($" typedef {functionInfo.ReturnType} ({classInfo.NativeName}::*{functionInfo.UniqueName}_Signature)({thunkParams}){t};");
contents.AppendLine($" typedef {functionInfo.ReturnType} ({classInfo.NativeName}Internal::*{functionInfo.UniqueName}_Internal_Signature)({thunkParams}){t};");
if (!(buildData.Toolchain is Platforms.UnixToolchain))
{
// MSVC or other compiler
contents.AppendLine($" typedef {functionInfo.ReturnType} ({classInfo.NativeName}Internal::*{functionInfo.UniqueName}_Internal_Signature)({thunkParams}){t};");
}
}
contents.AppendLine("");

14
Source/Tools/Flax.Build/Build/Plugins/VisualScriptingPlugin.cs
View File

@@ -67,19 +67,7 @@ namespace Flax.Build.Plugins
contents.AppendLine(" static THREADLOCAL void* WrapperCallInstance = nullptr;");
contents.AppendLine(" if (WrapperCallInstance == object)");
contents.AppendLine(" {");
contents.AppendLine(" // Prevent stack overflow by calling base method");
contents.AppendLine(" const auto scriptVTableBase = object->GetType().Script.ScriptVTableBase;");
contents.Append($" return (this->**({functionInfo.UniqueName}_Internal_Signature*)&scriptVTableBase[{scriptVTableOffset} + 2])(");
separator = false;
for (var i = 0; i < functionInfo.Parameters.Count; i++)
{
var parameterInfo = functionInfo.Parameters[i];
if (separator)
contents.Append(", ");
separator = true;
contents.Append(parameterInfo.Name);
}
contents.AppendLine(");");
BindingsGenerator.GenerateCppVirtualWrapperCallBaseMethod(buildData, contents, classInfo, functionInfo, "object->GetType().Script.ScriptVTableBase", scriptVTableOffset);
contents.AppendLine(" }");
contents.AppendLine(" auto scriptVTable = (VisualScript::Method**)object->GetType().Script.ScriptVTable;");
contents.AppendLine($" ASSERT(scriptVTable && scriptVTable[{scriptVTableOffset}]);");