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Fix disabling NativeToManaged map for classes with vtable (#1696)

* dont generate GetInstance on classes with disabled NativeToManaged map

* disable vtable hooking for classes with disabled ManagedToNative

* throw exception when trying to inherit from class with disabled NativeToManaged map
pull/1698/head
Fabio Anderegg 3 years ago committed by GitHub
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  1. 167
      src/Generator/Generators/CSharp/CSharpSources.cs

167
src/Generator/Generators/CSharp/CSharpSources.cs

@ -1655,23 +1655,31 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat @@ -1655,23 +1655,31 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat
if (wrappedEntries.Count == 0)
return;
bool generateNativeToManaged = Options.GenerateNativeToManagedFor(@class);
PushBlock(BlockKind.Region);
WriteLine("#region Virtual table interop");
NewLine();
// Generate a delegate type for each method.
foreach (var method in wrappedEntries.Select(e => e.Method).Where(m => !m.Ignore))
GenerateVTableMethodDelegates(containingClass, method.Namespace.IsDependent ?
(Method)method.InstantiatedFrom : method);
var hasVirtualDtor = wrappedEntries.Any(e => e.Method.IsDestructor);
bool hasDynamicBase = @class.NeedsBase && @class.BaseClass.IsDynamic;
var originalTableClass = @class.IsDependent ? @class.Specializations[0] : @class;
var destructorOnly = "destructorOnly";
using (WriteBlock($"internal static{(hasDynamicBase ? " new" : string.Empty)} class VTableLoader"))
// vtable hooks don't work without a NativeToManaged map, because we can't look up the managed
// instance from a native pointer without the map, so don't generate them here.
// this also means we can't inherit from this class and override virtual methods in C#
if (generateNativeToManaged)
{
WriteLines($@"
// Generate a delegate type for each method.
foreach (var method in wrappedEntries.Select(e => e.Method).Where(m => !m.Ignore))
GenerateVTableMethodDelegates(containingClass, method.Namespace.IsDependent ?
(Method)method.InstantiatedFrom : method);
var hasVirtualDtor = wrappedEntries.Any(e => e.Method.IsDestructor);
var destructorOnly = "destructorOnly";
using (WriteBlock($"internal static{(hasDynamicBase ? " new" : string.Empty)} class VTableLoader"))
{
WriteLines($@"
private static volatile bool initialized;
private static readonly IntPtr*[] ManagedVTables = new IntPtr*[{@class.Layout.VTablePointers.Count}];{(hasVirtualDtor ? $@"
private static readonly IntPtr*[] ManagedVTablesDtorOnly = new IntPtr*[{@class.Layout.VTablePointers.Count}];" : "")}
@ -1681,80 +1689,81 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat @@ -1681,80 +1689,81 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat
SafeHandles = new global::System.Collections.Generic.List<CppSharp.Runtime.SafeUnmanagedMemoryHandle>();
", trimIndentation: true);
using (WriteBlock($"static VTableLoader()"))
{
foreach (var entry in wrappedEntries.Distinct().Where(e => !e.Method.Ignore))
using (WriteBlock($"static VTableLoader()"))
{
var name = GetVTableMethodDelegateName(entry.Method);
WriteLine($"{name + "Instance"} += {name}Hook;");
}
for (var i = 0; i < wrappedEntries.Count; ++i)
{
var entry = wrappedEntries[i];
if (!entry.Method.Ignore)
foreach (var entry in wrappedEntries.Distinct().Where(e => !e.Method.Ignore))
{
var name = GetVTableMethodDelegateName(entry.Method);
WriteLine($"Thunks[{i}] = Marshal.GetFunctionPointerForDelegate({name + "Instance"});");
WriteLine($"{name + "Instance"} += {name}Hook;");
}
for (var i = 0; i < wrappedEntries.Count; ++i)
{
var entry = wrappedEntries[i];
if (!entry.Method.Ignore)
{
var name = GetVTableMethodDelegateName(entry.Method);
WriteLine($"Thunks[{i}] = Marshal.GetFunctionPointerForDelegate({name + "Instance"});");
}
}
}
}
NewLine();
NewLine();
using (WriteBlock($"public static CppSharp.Runtime.VTables SetupVTables(IntPtr instance, bool {destructorOnly} = false)"))
{
WriteLine($"if (!initialized)");
using (WriteBlock($"public static CppSharp.Runtime.VTables SetupVTables(IntPtr instance, bool {destructorOnly} = false)"))
{
WriteOpenBraceAndIndent();
WriteLine($"lock (ManagedVTables)");
WriteOpenBraceAndIndent();
WriteLine($"if (!initialized)");
{
WriteOpenBraceAndIndent();
WriteLine($"initialized = true;");
WriteLine($"VTables.Tables = {($"new IntPtr[] {{ {string.Join(", ", originalTableClass.Layout.VTablePointers.Select(x => $"*(IntPtr*)(instance + {x.Offset})"))} }}")};");
WriteLine($"VTables.Methods = new Delegate[{originalTableClass.Layout.VTablePointers.Count}][];");
if (hasVirtualDtor)
AllocateNewVTables(@class, wrappedEntries, destructorOnly: true, "ManagedVTablesDtorOnly");
AllocateNewVTables(@class, wrappedEntries, destructorOnly: false, "ManagedVTables");
if (!hasVirtualDtor)
WriteLine($"lock (ManagedVTables)");
WriteOpenBraceAndIndent();
WriteLine($"if (!initialized)");
{
WriteLine($"if ({destructorOnly})");
WriteLineIndent("return VTables;");
WriteOpenBraceAndIndent();
WriteLine($"initialized = true;");
WriteLine($"VTables.Tables = {($"new IntPtr[] {{ {string.Join(", ", originalTableClass.Layout.VTablePointers.Select(x => $"*(IntPtr*)(instance + {x.Offset})"))} }}")};");
WriteLine($"VTables.Methods = new Delegate[{originalTableClass.Layout.VTablePointers.Count}][];");
if (hasVirtualDtor)
AllocateNewVTables(@class, wrappedEntries, destructorOnly: true, "ManagedVTablesDtorOnly");
AllocateNewVTables(@class, wrappedEntries, destructorOnly: false, "ManagedVTables");
if (!hasVirtualDtor)
{
WriteLine($"if ({destructorOnly})");
WriteLineIndent("return VTables;");
}
UnindentAndWriteCloseBrace();
}
UnindentAndWriteCloseBrace();
UnindentAndWriteCloseBrace();
}
UnindentAndWriteCloseBrace();
UnindentAndWriteCloseBrace();
}
NewLine();
NewLine();
if (hasVirtualDtor)
{
WriteLine($"if ({destructorOnly})");
if (hasVirtualDtor)
{
WriteOpenBraceAndIndent();
AssignNewVTableEntries(@class, "ManagedVTablesDtorOnly");
UnindentAndWriteCloseBrace();
WriteLine($"if ({destructorOnly})");
{
WriteOpenBraceAndIndent();
AssignNewVTableEntries(@class, "ManagedVTablesDtorOnly");
UnindentAndWriteCloseBrace();
}
WriteLine("else");
{
WriteOpenBraceAndIndent();
AssignNewVTableEntries(@class, "ManagedVTables");
UnindentAndWriteCloseBrace();
}
}
WriteLine("else");
else
{
WriteOpenBraceAndIndent();
AssignNewVTableEntries(@class, "ManagedVTables");
UnindentAndWriteCloseBrace();
}
}
else
{
AssignNewVTableEntries(@class, "ManagedVTables");
}
WriteLine("return VTables;");
WriteLine("return VTables;");
}
}
NewLine();
}
NewLine();
if (!hasDynamicBase)
WriteLine("protected CppSharp.Runtime.VTables __vtables;");
@ -1775,9 +1784,13 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat @@ -1775,9 +1784,13 @@ internal static bool {Helpers.TryGetNativeToManagedMappingIdentifier}(IntPtr nat
using (WriteBlock($"internal {(hasDynamicBase ? "override" : "virtual")} void SetupVTables(bool destructorOnly = false)"))
{
WriteLines($@"
if (__VTables.IsTransient)
__VTables = VTableLoader.SetupVTables(__Instance, destructorOnly);", trimIndentation: true);
// same reason as above, we can't hook vtable without ManagedToNative map
if (generateNativeToManaged)
{
WriteLines($@"
if (__VTables.IsTransient)
__VTables = VTableLoader.SetupVTables(__Instance, destructorOnly);", trimIndentation: true);
}
}
WriteLine("#endregion");
@ -2399,22 +2412,16 @@ internal static{(@new ? " new" : string.Empty)} {printedClass} __GetOrCreateInst @@ -2399,22 +2412,16 @@ internal static{(@new ? " new" : string.Empty)} {printedClass} __GetOrCreateInst
NewLine();
}
if (HasVirtualTables(@class))
// __GetInstance doesn't work without a ManagedToNativeMap, so don't generate it
if (HasVirtualTables(@class) && generateNativeToManaged)
{
@new = @class.HasBase && HasVirtualTables(@class.Bases.First().Class);
WriteLines($@"
internal static{(@new ? " new" : string.Empty)} {printedClass} __GetInstance({TypePrinter.IntPtrType} native)
{{");
if (generateNativeToManaged)
{
WriteLines($@"
{{
if (!{Helpers.TryGetNativeToManagedMappingIdentifier}(native, out var managed))
throw new global::System.Exception(""No managed instance was found"");");
}
WriteLines($@"
throw new global::System.Exception(""No managed instance was found"");
var result = ({printedClass})managed;
if (result.{Helpers.OwnsNativeInstanceIdentifier})
result.SetupVTables();
@ -2950,12 +2957,24 @@ internal static{(@new ? " new" : string.Empty)} {printedClass} __GetInstance({Ty @@ -2950,12 +2957,24 @@ internal static{(@new ? " new" : string.Empty)} {printedClass} __GetInstance({Ty
private void GenerateClassConstructor(Method method, Class @class)
{
var generateNativeToManaged = Options.GenerateNativeToManagedFor(@class);
if (!generateNativeToManaged)
{
// if we don't have a NativeToManaged map, we can't do vtable hooking, because we can't
// fetch the managed class from the native pointer. vtable hooking is required to allow C++
// code to call virtual methods defined on a C++ class but overwritten in a C# class.
// todo: throwing an exception at runtime is ugly, we should seal the class instead
var typeFullName = TypePrinter.VisitClassDecl(@class).Type.Replace("global::", string.Empty);
WriteLine($@"if (GetType().FullName != ""{typeFullName}"")");
WriteLineIndent($@"throw new Exception(""{typeFullName}: Can't inherit from classes with disabled NativeToManaged map"");");
}
var @internal = TypePrinter.PrintNative(
@class.IsAbstractImpl ? @class.BaseClass : @class);
WriteLine($"{Helpers.InstanceIdentifier} = Marshal.AllocHGlobal(sizeof({@internal}));");
WriteLine($"{Helpers.OwnsNativeInstanceIdentifier} = true;");
if (Options.GenerateNativeToManagedFor(@class))
if (generateNativeToManaged)
WriteLine($"{Helpers.RecordNativeToManagedMappingIdentifier}({Helpers.InstanceIdentifier}, this);");
if (method.IsCopyConstructor)

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