[Mono-bugs] [Bug 472845] New: Need proper support for __arglist keyword in compiler and P/Invoke

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=472845


           Summary: Need proper support for __arglist keyword in compiler
                    and P/Invoke
    Classification: Mono
           Product: Mono: Runtime
           Version: 2.2.x
          Platform: Other
        OS/Version: Other
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: io-layer
        AssignedTo: dick at novell.com
        ReportedBy: eugeny.grishul at gmail.com
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---


User-Agent:       Opera/9.63 (Windows NT 6.0; U; ru) Presto/2.1.1

1) gmcs currently supports only __arglist keyword, but sometimes generates
incorrect CIL. That code works while compiling with csc.exe, but leads to
segmentation fault/incorrect CIL after gmsc (I tried it on Mac OS 10.5, Mono
2.2 ):
================== CODE ===========================
using System;
using System.Runtime.InteropServices;
using System.Threading;

namespace NObjective
{
    public class Program
    {
        static volatile bool ProcessExiting = false;

        [DllImport( "libc.dylib" )]
        public extern static void printf( string format, __arglist );

        private static void ArglistMethod(__arglist )
        {
            var iter = new ArgIterator( __arglist );

            for( var n = iter.GetRemainingCount(); n > 0; n-- )
                Console.WriteLine( TypedReference.ToObject( iter.GetNextArg() )
);
        }

        static unsafe void Main( string[] args )
        {
            ArglistMethod( __arglist( 1, 2, 3 ) );
        }
    }
}
===================================================
2) Mono VES currently supports mkrefany, refanyval, refanytype, arglist
instructions for non-P/Invoke scenario. But only csc.exe can insert
mkrefany,refanyval,refanytype CIL instructions into assembly.

3) Mono JIT & P/Invoke layer don't like __arglist parameters and reports
something like this: Invalid IL code in NObjective.Program:Main (string[]):
IL_0021: ret
================== CODE ===========================
[DllImport( "libc.dylib" )]
public extern static void printf( string format, __arglist );

..

printf( "ytu", __arglist( "44" ) );
===================================================
If compiler  will be able generate correct CIL it will be useful for debugging
future P/Invoke layer that will able to work with __arglist

My project (NObjective) contains about of 43000 generated methods (generated
from Objective-C method signatures) accessible by user that looks like:

================== CODE ===========================
unsafe public static bool writeToURL_atomically_( this NSData ___this, NSURL
url, bool atomically ) {
    RuntimeObject ___occuredException;
    var ___result = NativeMethods.writeToURL_atomically_( ___this,
CachedSelectors.writeToURL_atomically_, out ___occuredException, sizeof( NSURL
) + sizeof( bool ), url, atomically );
    if( ___occuredException != RuntimeObject.Null ) throw
RuntimeException.Create( ___occuredException );     
    return ___result;
}

unsafe public static bool writeToURL_options_error_( this NSData ___this, NSURL
url, uint options, ref NSError error ) {
    RuntimeObject ___occuredException;
    var ___result = NativeMethods.writeToURL_options_error_( ___this,
CachedSelectors.writeToURL_options_error_, out ___occuredException, sizeof(
NSURL ) + sizeof( uint ) + sizeof( IntPtr ), url, options, ref error );
    if( ___occuredException != RuntimeObject.Null ) throw
RuntimeException.Create( ___occuredException ); 
    return ___result;
}

(See full source:
http://code.google.com/p/nobjective/source/browse/trunk/Proxies/10.5/HIToolbox.cs)
===================================================
Each generated method have a generated P/Invoke counterpart with same entry
point and nearly same signature (another 43000 methods!):
================== CODE ===========================
[DllImport(Runtime.InteropLibrary, EntryPoint = "objc_msgSend_eh2")]
public static extern bool writeToURL_atomically_( RuntimeObject ___object,
Selector ___selector, out RuntimeObject ___occuredException, int ___stackSize,
NSURL url, bool atomically );

[DllImport(Runtime.InteropLibrary, EntryPoint = "objc_msgSend_eh2")]
public static extern bool writeToURL_options_error_( RuntimeObject ___object,
Selector ___selector, out RuntimeObject ___occuredException, int ___stackSize,
NSURL url, uint options, ref NSError error );
===================================================

With proper __arglist support in VES/gmcs unnecessary P/Invokes can be easily
removed ( -43000 methods = assembly will hold much less metadata ) and all
calls redirected to small set __arglist methods (one method per primitive
return type - int,IntPtr etc.):

================== CODE ===========================
unsafe public static bool writeToURL_atomically_( this NSData ___this, NSURL
url, bool atomically ) {
    RuntimeObject ___occuredException;
    var ___result = NativeMethods.FutureArglistMethod( ___this,
CachedSelectors.writeToURL_atomically_, out ___occuredException, sizeof( NSURL
) + sizeof( bool ), __arglist( url, atomically ) );
    if( ___occuredException != RuntimeObject.Null ) throw
RuntimeException.Create( ___occuredException );     
    return ___result;
}

unsafe public static bool writeToURL_options_error_( this NSData ___this, NSURL
url, uint options, ref NSError error ) {
    RuntimeObject ___occuredException;
    var ___result = NativeMethods.FutureArglistMethod( ___this,
CachedSelectors.writeToURL_options_error_, out ___occuredException, sizeof(
NSURL ) + sizeof( uint ) + sizeof( IntPtr ), __arglist( url, options, ref error
) );
    if( ___occuredException != RuntimeObject.Null ) throw
RuntimeException.Create( ___occuredException ); 
    return ___result;
}

..


[DllImport(Runtime.InteropLibrary, EntryPoint = "objc_msgSend_eh2")]
public static extern bool FutureArglistMethod( RuntimeObject ___object,
Selector ___selector, out RuntimeObject ___occuredException, int ___stackSize,
__arglist );
===================================================

WBR,
Eugeny Grishul

Reproducible: Always

Actual Results:  
P/Invoke not works with vararg (__arglist) calls
gmcs not support __makeref, __refvalue, __reftype keywords.
gmcs generates incorrect CIL for __arglist

Expected Results:  
All is OK.

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