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[generator] Generate block callback signatures using only blittable t…
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…ypes.

Change the generated block callbacks so that we only use blittable types (so
that the callbacks can become [UnmanagedCallersOnly]).

This involved two changes:

* Use pointer types instead of ref/out types ('int*' instead of 'ref/out
  int').
* Use 'byte' instead of 'bool'.

Contributes towards xamarin#15783.
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@rolfbjarne
rolfbjarne committed Mar 6, 2023
1 parent e013c10 commit b79fc1b
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Showing 2 changed files with 102 additions and 48 deletions.
139 changes: 91 additions & 48 deletions src/bgen/Generator.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -697,7 +697,7 @@ public TrampolineInfo MakeTrampoline (Type t)
}

var mi = t.GetMethod ("Invoke");
var pars = new StringBuilder ();
var pars = new List<TrampolineParameterInfo> ();
var convert = new StringBuilder ();
var invoke = new StringBuilder ();
var clear = new StringBuilder ();
Expand All @@ -720,24 +720,26 @@ public TrampolineInfo MakeTrampoline (Type t)
} else if (TypeManager.INativeObject.IsAssignableFrom (mi.ReturnType)) {
returntype = Generator.NativeHandleType;
returnformat = "return {0}.GetHandle ();";
} else if (mi.ReturnType == TypeManager.System_Boolean) {
returntype = "byte";
returnformat = "return {0} ? (byte) 1 : (byte) 0;";
} else {
returntype = FormatType (mi.DeclaringType, mi.ReturnType);
}

pars.Append ($"IntPtr block");
pars.Add (new TrampolineParameterInfo ("IntPtr", "block"));
var parameters = mi.GetParameters ();
foreach (var pi in parameters) {
string isForcedOwns;
var isForced = HasForcedAttribute (pi, out isForcedOwns);

pars.Append (", ");
if (pi != parameters [0])
invoke.Append (", ");

var safe_name = pi.Name.GetSafeParamName ();

if (IsWrappedType (pi.ParameterType)) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
if (IsProtocolInterface (pi.ParameterType)) {
invoke.AppendFormat (" Runtime.GetINativeObject<{1}> ({0}, false)!", safe_name, pi.ParameterType);
} else if (isForced) {
Expand All @@ -751,7 +753,7 @@ public TrampolineInfo MakeTrampoline (Type t)
if (Frameworks.HaveCoreMedia) {
// special case (false) so it needs to be before the _real_ INativeObject check
if (pi.ParameterType == TypeManager.CMSampleBuffer) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
if (BindThirdPartyLibrary)
invoke.AppendFormat ("{0} == IntPtr.Zero ? null! : Runtime.GetINativeObject<CMSampleBuffer> ({0}, false)!", safe_name);
else
Expand All @@ -762,50 +764,57 @@ public TrampolineInfo MakeTrampoline (Type t)

if (Frameworks.HaveAudioToolbox) {
if (pi.ParameterType == TypeManager.AudioBuffers) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("new global::AudioToolbox.AudioBuffers ({0})", safe_name);
continue;
}
}

if (TypeManager.INativeObject.IsAssignableFrom (pi.ParameterType)) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("new {0} ({1}, false)", pi.ParameterType, safe_name);
continue;
}

if (pi.ParameterType.IsByRef) {
var nt = pi.ParameterType.GetElementType ();
if (pi.IsOut) {
clear.AppendFormat ("{0} = {1};", safe_name, nt.IsValueType ? "default (" + FormatType (null, nt) + ")" : "null");
if (nt == TypeManager.System_Boolean) {
clear.AppendFormat ("*{0} = 0;", safe_name);
} else {
clear.AppendFormat ("*{0} = {1};", safe_name, nt.IsValueType ? "default (" + FormatType (null, nt) + ")" : "null");
}
}
if (nt.IsValueType) {
string marshal = string.Empty;
if (nt == TypeManager.System_Boolean)
marshal = "[System.Runtime.InteropServices.MarshalAs (System.Runtime.InteropServices.UnmanagedType.I1)] ";
string fnt;
string invoke_name;
string arg_byref = pi.IsOut ? "out " : "ref ";
var outOrRef = pi.IsOut ? "out" : "ref";
var nullable = TypeManager.GetUnderlyingNullableType (nt);
if (nullable != null) {
fnt = "IntPtr";
fnt = FormatType (null, nullable);
invoke_name = $"__xamarin_nullified__{pi.Position}";
arg_byref = String.Empty;
convert.AppendLine ($"{nullable.Name}? {invoke_name} = null;");
convert.AppendLine ("if (value != IntPtr.Zero)");
convert.Append ($"\t{invoke_name} = * ({nullable.Name} *) value;");
convert.AppendLine ("if (value != null)");
convert.AppendLine ($"\t{invoke_name} = *value;");
postConvert.AppendLine ($"if (value != null && {invoke_name}.HasValue)");
postConvert.AppendLine ($"\t*value = {invoke_name}.Value;");
} else if (nt == TypeManager.System_Boolean) {
fnt = "byte";
invoke_name = $"__xamarin_bool__{pi.Position}";
convert.AppendLine ($"bool {invoke_name} = *{safe_name} != 0;");
postConvert.AppendLine ($"*{safe_name} = {invoke_name} ? (byte) 1 : (byte) 0;");
} else {
fnt = FormatType (null, nt);
invoke_name = safe_name;
invoke_name = $"global::System.Runtime.CompilerServices.Unsafe.AsRef<{fnt}> ({safe_name})";
}
pars.AppendFormat ("{3}{0}{1} {2}", arg_byref, fnt, safe_name, marshal);
invoke.AppendFormat ("{0} {1}", pi.IsOut ? "out" : "ref", invoke_name);
pars.Add (new TrampolineParameterInfo (fnt + "*", safe_name));
invoke.AppendFormat ("{0} {1}", outOrRef, invoke_name);
continue;
} else if (pi.ParameterType.IsByRef) {
} else {
var refname = $"__xamarin_pref{pi.Position}";
convert.Append ($"var {refname} = Runtime.GetINativeObject<{RenderType (nt)}> ({safe_name}, false)!;");
pars.Append ($"ref {NativeHandleType} {safe_name}");
postConvert.Append ($"{safe_name} = {refname}.GetHandle ();");
convert.Append ($"var {refname} = Runtime.GetINativeObject<{RenderType (nt)}> (*{safe_name}, false)!;");
pars.Add (new TrampolineParameterInfo ($"{NativeHandleType}*", safe_name));
postConvert.Append ($"*{safe_name} = {refname}.GetHandle ();");
if (pi.IsOut)
invoke.Append ("out ");
else
Expand All @@ -814,30 +823,34 @@ public TrampolineInfo MakeTrampoline (Type t)
continue;
}
} else if (GetNativeEnumToManagedExpression (pi.ParameterType, out var preExpression, out var postExpression, out var nativeType)) {
pars.AppendFormat ("{0} {1}", nativeType, safe_name);
pars.Add (new TrampolineParameterInfo (nativeType, safe_name));
invoke.Append (preExpression).Append (safe_name).Append (postExpression);
continue;
} else if (pi.ParameterType == TypeManager.System_Boolean) {
pars.Add (new TrampolineParameterInfo ("byte", safe_name));
invoke.AppendFormat ("{0} != 0", safe_name);
continue;
} else if (pi.ParameterType.IsValueType) {
pars.AppendFormat ("{0} {1}", FormatType (null, pi.ParameterType), safe_name);
pars.Add (new TrampolineParameterInfo (FormatType (null, pi.ParameterType), safe_name));
invoke.AppendFormat ("{0}", safe_name);
continue;
}

if (pi.ParameterType == TypeManager.System_String_Array) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("CFArray.StringArrayFromHandle ({0})!", safe_name);
continue;
}
if (pi.ParameterType == TypeManager.System_String) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("CFString.FromHandle ({0})!", safe_name);
continue;
}

if (pi.ParameterType.IsArray) {
Type et = pi.ParameterType.GetElementType ();
if (IsWrappedType (et)) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("CFArray.ArrayFromHandle<{0}> ({1})!", FormatType (null, et), safe_name);
continue;
}
Expand All @@ -848,7 +861,7 @@ public TrampolineInfo MakeTrampoline (Type t)
delegate_types [pi.ParameterType.FullName] = pi.ParameterType.GetMethod ("Invoke");
}
if (AttributeManager.HasAttribute<BlockCallbackAttribute> (pi)) {
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("NID{0}.Create ({1})!", Nomenclator.GetTrampolineName (pi.ParameterType), safe_name);
// The trampoline will eventually be generated in the final loop
} else {
Expand All @@ -859,7 +872,7 @@ public TrampolineInfo MakeTrampoline (Type t)
ErrorHelper.Warning (1115, safe_name, t.FullName);
}
}
pars.AppendFormat ("{1} {0}", safe_name, NativeHandleType);
pars.Add (new TrampolineParameterInfo (NativeHandleType, safe_name));
invoke.AppendFormat ("({0}) Marshal.GetDelegateForFunctionPointer ({1}, typeof ({0}))", pi.ParameterType, safe_name);
}
continue;
Expand All @@ -873,7 +886,7 @@ public TrampolineInfo MakeTrampoline (Type t)
var trampoline_name = Nomenclator.GetTrampolineName (t);
var ti = new TrampolineInfo (userDelegate: FormatType (null, t),
delegateName: "D" + trampoline_name,
pars: pars.ToString (),
pars: string.Join (", ", pars.Select (v => v.Type + " " + v.ParameterName)),
convert: convert.ToString (),
invoke: invoke.ToString (),
returnType: returntype,
Expand All @@ -894,9 +907,11 @@ public TrampolineInfo MakeTrampoline (Type t)
// Returns the actual way in which the type t must be marshalled
// for example "UIView foo" is generated as "foo.Handle"
//
public string MarshalParameter (MethodInfo mi, ParameterInfo pi, bool null_allowed_override, PropertyInfo propInfo = null, bool castEnum = true)
public string MarshalParameter (MethodInfo mi, ParameterInfo pi, bool null_allowed_override, PropertyInfo propInfo = null, bool castEnum = true, bool usingBlittableNativeTypes = false, StringBuilder convs = null)
{
if (pi.ParameterType.IsByRef && pi.ParameterType.GetElementType ().IsValueType == false) {
if (usingBlittableNativeTypes)
return "&" + pi.Name + "Value";
return "ref " + pi.Name + "Value";
}

Expand Down Expand Up @@ -944,8 +959,11 @@ public string MarshalParameter (MethodInfo mi, ParameterInfo pi, bool null_allow
}
}

if (pi.ParameterType.IsValueType)
if (pi.ParameterType.IsValueType) {
if (usingBlittableNativeTypes && pi.ParameterType == TypeManager.System_Boolean)
return safe_name + " ? (byte) 1 : (byte) 0";
return safe_name;
}

MarshalType mt;
if (marshalTypes.TryGetMarshalType (pi.ParameterType, out mt)) {
Expand All @@ -969,8 +987,19 @@ public string MarshalParameter (MethodInfo mi, ParameterInfo pi, bool null_allow
var et = pi.ParameterType.GetElementType ();
var nullable = TypeManager.GetUnderlyingNullableType (et);
if (nullable != null) {
return "converted";
return $"converted_{safe_name}";
} else if (et.IsValueType)
if (usingBlittableNativeTypes) {
if (et == TypeManager.System_Boolean) {
if (pi.IsOut)
convs!.Append ($"{safe_name} = false;");
return $"(byte*) global::System.Runtime.CompilerServices.Unsafe.AsPointer<bool> (ref {safe_name})";
}
var blittableType = FormatType (mi.DeclaringType, et);
if (pi.IsOut)
convs!.Append ($"{safe_name} = default ({blittableType});");
return $"({blittableType}*) global::System.Runtime.CompilerServices.Unsafe.AsPointer<{blittableType}> (ref {safe_name})";
}
return (pi.IsOut ? "out " : "ref ") + safe_name;
}

Expand Down Expand Up @@ -1711,15 +1740,15 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
print ("");
print ("[UnmanagedFunctionPointerAttribute (CallingConvention.Cdecl)]");
print ("[UserDelegateType (typeof ({0}))]", ti.UserDelegate);
print ("internal delegate {0} {1} ({2});", ti.ReturnType, ti.DelegateName, ti.Parameters);
print ("unsafe internal delegate {0} {1} ({2});", ti.ReturnType, ti.DelegateName, ti.Parameters);
print ("");
print ("//\n// This class bridges native block invocations that call into C#\n//");
print ("static internal class {0} {{", ti.StaticName); indent++;
// it can't be conditional without fixing https://github.com/mono/linker/issues/516
// but we have a workaround in place because we can't fix old, binary bindings so...
// print ("[Preserve (Conditional=true)]");
// For .NET we fix it using the DynamicDependency attribute below
print ("static internal readonly {0} Handler = Invoke;", ti.DelegateName);
print ("unsafe static internal readonly {0} Handler = Invoke;", ti.DelegateName);
print ("");
#if NET
print ("[Preserve (Conditional = true)]");
Expand All @@ -1734,16 +1763,21 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
// FIXME: right now we only support 'null' when the delegate does not return a value
// otherwise we will need to know the default value to be returned (likely uncommon)
if (is_void) {
print ("if (del != null)");
print ("if (del != null) {");
indent++;
if (ti.Convert.Length > 0)
print (ti.Convert);
print ("del ({0});", ti.Invoke);
if (ti.PostConvert.Length > 0)
print (ti.PostConvert);
indent--;
if (ti.Clear.Length > 0) {
print ("else");
print ("} else {");
indent++;
print (ti.Clear);
indent--;
}
print ("}");
} else {
if (ti.Convert.Length > 0)
print (ti.Convert);
Expand Down Expand Up @@ -1819,7 +1853,8 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
convs: out convs,
disposes: out disposes,
by_ref_processing: out by_ref_processing,
by_ref_init: out by_ref_init);
by_ref_init: out by_ref_init,
usingBlittableNativeTypes: true);

if (by_ref_init.Length > 0)
print (by_ref_init.ToString ());
Expand All @@ -1839,8 +1874,13 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
print (disposes.ToString ());
if (by_ref_processing.Length > 0)
print (sw, by_ref_processing.ToString ());
if (use_temp_return)
print ("return ret!;");
if (use_temp_return) {
if (mi.ReturnType == TypeManager.System_Boolean) {
print ("return ret != 0;");
} else {
print ("return ret!;");
}
}
indent--; print ("}");
indent--;
print ("}} /* class {0} */", ti.NativeInvokerName);
Expand Down Expand Up @@ -3643,7 +3683,7 @@ bool Is64BitiOSOnly (ICustomAttributeProvider provider)
// @convs: conversions to perform before the invocation
// @disposes: dispose operations to perform after the invocation
// @by_ref_processing
void GenerateTypeLowering (MethodInfo mi, bool null_allowed_override, out StringBuilder args, out StringBuilder convs, out StringBuilder disposes, out StringBuilder by_ref_processing, out StringBuilder by_ref_init, PropertyInfo propInfo = null, bool castEnum = true)
void GenerateTypeLowering (MethodInfo mi, bool null_allowed_override, out StringBuilder args, out StringBuilder convs, out StringBuilder disposes, out StringBuilder by_ref_processing, out StringBuilder by_ref_init, PropertyInfo propInfo = null, bool castEnum = true, bool usingBlittableNativeTypes = false)
{
args = new StringBuilder ();
convs = new StringBuilder ();
Expand All @@ -3658,18 +3698,21 @@ void GenerateTypeLowering (MethodInfo mi, bool null_allowed_override, out String
if (!IsTarget (pi)) {
// Construct invocation
args.Append (", ");
args.Append (MarshalParameter (mi, pi, null_allowed_override, propInfo, castEnum));
args.Append (MarshalParameter (mi, pi, null_allowed_override, propInfo, castEnum, usingBlittableNativeTypes, convs));

if (pi.ParameterType.IsByRef) {
var et = pi.ParameterType.GetElementType ();
var nullable = TypeManager.GetUnderlyingNullableType (et);
if (nullable != null) {
convs.Append ("var converted = IntPtr.Zero;\n");
convs.Append ($"var v = default ({FormatType (mi.DeclaringType, nullable)});\n");
convs.Append ("if (value.HasValue) {\n");
convs.Append ("\tv = value.Value;\n");
convs.Append ("\tconverted = new IntPtr (&v);\n");
var nt = FormatType (mi.DeclaringType, nullable);
convs.Append ($"{nt}* converted_{safe_name} = null;\n");
convs.Append ($"{nt} converted_{safe_name}_v = default ({nt});\n");
convs.Append ($"if ({safe_name}.HasValue) {{\n");
convs.Append ($"\tconverted_{safe_name}_v = {safe_name}.Value;\n");
convs.Append ($"\tconverted_{safe_name} = &converted_{safe_name}_v;\n");
convs.Append ("}\n");
by_ref_processing.AppendLine ($"if ({safe_name}.HasValue)");
by_ref_processing.AppendLine ($"\t{safe_name} = *converted_{safe_name};");
}
}
}
Expand Down
11 changes: 11 additions & 0 deletions src/bgen/TrampolineInfo.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,3 +59,14 @@ public string NativeInvokerName {
}
}
}

class TrampolineParameterInfo {
public string Type;
public string ParameterName;

public TrampolineParameterInfo (string type, string parameterName)
{
Type = type;
ParameterName = parameterName;
}
}

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