Re: [Mono-dev] Embedded API: .ctor method signature query [mono]

2016-03-04 Thread Jonathan Mitchell 
HI Robert

> 
> You may want to file a bug, though.

Bug is in at:
https://bugzilla.xamarin.com/show_bug.cgi?id=39343

After logging the bug I managed to fix it myself on my current target 4.0.0. 
https://github.com/mono/mono/pull/2724

4.2.0 will need this too.

Jonathan
> 
> Robert
> 
> 
> On 03.03.2016 19:28, Jonathan Mitchell wrote:
>> HI Robert
>> 
>> Thanks for that.
>> I think you are right.
>> I call hundreds of methods that take Obj`1 arguments with out issue but I 
>> see that I have had to construct a number of helper methods to deal with 
>> cases of Obj`2 which failed signature resolution.
>> 
>> I presume that  managed code execution doesn’t involve calls to 
>> mono_method_desc_new() - are thunks used instead?
>> One of the difficulties, I find, of working with the embedded API is trying 
>> to visualise just how a particular managed code statement is implemented 
>> within the runtime.
>> 
>> I was hoping to be able to call the constructor from C with a pointer to a 
>> static (MonoString *)fund(MonoString *).
>> Not sure if that would even fly.
>> 
>> As a work around I will use an internal call.
>> 
>> Shall I log this as a bug and reference this thread?
>> 
>> Thanks a lot for replying.
>> 
>> Jonathan
>> 
>>> On 3 Mar 2016, at 18:02, Robert Jordan  wrote:
>>> 
>>> On 03.03.2016 14:36, Jonathan Mitchell wrote:
 HI
 
 I want to call the following constructor via the embedded API:
 
 public CloudClient(Func filePathCallback)
 
 All my other embedded method and constructor calls work okay but there is 
 an issue with this one - it is the only place I use a System.Func.
 The API reports that a method cannot be found for signature 
 .ctor(System.Func`2)
 When I dump out the class method names I see .ctor(System.Func`2) listed.
 
 Any ideas on this one?
>>> 
>>> It looks like a bug in mono_method_desc_new ():
>>> 
>>> https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L378
>>> 
>>> The function is treating
>>> 
>>> .ctor(System.Func`2)
>>> 
>>> like a method with 2 arguments:
>>> 
>>> arg0 = System.Func`2>> arg1 = string>
>>> 
>>> This is obviously wrong :)
>>> 
>>> The function is then storing the (wrong) argument count
>>> for optimization purposes, and the comparison of methods
>>> is starting to fail:
>>> 
>>> https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L447
>>> 
>>> Robert
>>> 
>>> 
> 
> 
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Re: [Mono-dev] Embedded API: .ctor method signature query [mono]

2016-03-03 Thread Robert Jordan 

Hi Jonathan,

The JIT isn't using these functions for method look-ups.

mono_method_descs are mainly for embedders (and for
trivial method look-ups at some places inside the runtime).

They come handy when you want to get an overloaded
MonoMethod in C/C++:

easy:

desc = mono_method_desc_new (":Method(int, string, int)");
method = mono_method_desc_search_in_class (desc, class);
mono_method_desc_free (desc);

versus hard:

- enum methods with mono_class_get_methods ()
- check method name
- check param count
- check param types
...


If you're generating stubs automatically and don't
have a string description of the methods up front,
the hard way involving mono_class_get_methods () might
be better and faster.

You may want to file a bug, though.

Robert


On 03.03.2016 19:28, Jonathan Mitchell wrote:

HI Robert

Thanks for that.
I think you are right.
I call hundreds of methods that take Obj`1 arguments with out issue but I see that 
I have had to construct a number of helper methods to deal with cases of Obj`2 
which failed signature resolution.

I presume that  managed code execution doesn’t involve calls to 
mono_method_desc_new() - are thunks used instead?
One of the difficulties, I find, of working with the embedded API is trying to 
visualise just how a particular managed code statement is implemented within 
the runtime.

I was hoping to be able to call the constructor from C with a pointer to a 
static (MonoString *)fund(MonoString *).
Not sure if that would even fly.

As a work around I will use an internal call.

Shall I log this as a bug and reference this thread?

Thanks a lot for replying.

Jonathan


On 3 Mar 2016, at 18:02, Robert Jordan  wrote:

On 03.03.2016 14:36, Jonathan Mitchell wrote:

HI

I want to call the following constructor via the embedded API:

public CloudClient(Func filePathCallback)

All my other embedded method and constructor calls work okay but there is an issue 
with this one - it is the only place I use a System.Func.
The API reports that a method cannot be found for signature 
.ctor(System.Func`2)
When I dump out the class method names I see .ctor(System.Func`2) listed.

Any ideas on this one?


It looks like a bug in mono_method_desc_new ():

https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L378

The function is treating

.ctor(System.Func`2)

like a method with 2 arguments:

arg0 = System.Func`2

This is obviously wrong :)

The function is then storing the (wrong) argument count
for optimization purposes, and the comparison of methods
is starting to fail:

https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L447

Robert





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Re: [Mono-dev] Embedded API: .ctor method signature query [mono]

2016-03-03 Thread Jonathan Mitchell 
HI Robert

Thanks for that.
I think you are right.
I call hundreds of methods that take Obj`1 arguments with out issue but I 
see that I have had to construct a number of helper methods to deal with cases 
of Obj`2 which failed signature resolution.

I presume that  managed code execution doesn’t involve calls to 
mono_method_desc_new() - are thunks used instead?
One of the difficulties, I find, of working with the embedded API is trying to 
visualise just how a particular managed code statement is implemented within 
the runtime.

I was hoping to be able to call the constructor from C with a pointer to a 
static (MonoString *)fund(MonoString *).
Not sure if that would even fly.

As a work around I will use an internal call.

Shall I log this as a bug and reference this thread?

Thanks a lot for replying.

Jonathan

> On 3 Mar 2016, at 18:02, Robert Jordan  wrote:
> 
> On 03.03.2016 14:36, Jonathan Mitchell wrote:
>> HI
>> 
>> I want to call the following constructor via the embedded API:
>> 
>> public CloudClient(Func filePathCallback)
>> 
>> All my other embedded method and constructor calls work okay but there is an 
>> issue with this one - it is the only place I use a System.Func.
>> The API reports that a method cannot be found for signature 
>> .ctor(System.Func`2)
>> When I dump out the class method names I see .ctor(System.Func`2> string>) listed.
>> 
>> Any ideas on this one?
> 
> It looks like a bug in mono_method_desc_new ():
> 
> https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L378
> 
> The function is treating
> 
>   .ctor(System.Func`2)
> 
> like a method with 2 arguments:
> 
> arg0 = System.Func`2 arg1 = string>
> 
> This is obviously wrong :)
> 
> The function is then storing the (wrong) argument count
> for optimization purposes, and the comparison of methods
> is starting to fail:
> 
> https://github.com/mono/mono/blob/master/mono/metadata/debug-helpers.c#L447
> 
> Robert
> 
> 
> 

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