[mono] Initialize module's image ALC for dynamic objects

[kotlarmilos]

This PR initializes module's image ALC for dynamic objects created during the runtime.

Fixes #90164

[vargaz]

Maybe we should set the alc of the dynamic images instead ?

[kotlarmilos]

During initialization, the ALC is set in mono_reflection_dynimage_basic_init to default mono_alc_get_default:

runtime/src/mono/mono/metadata/sre.c

Line 1265 in 82fdd0b

image->image.alc = alc;

When retrieving custom attributes in mono_reflection_get_custom_attrs_by_type_handle, parameter MonoObjectHandle obj seems to be a MonoClass containing an image without ALC. Should the MonoObjectHandle's image contain the ALC?

[lambdageek]

During initialization, the ALC is set in mono_reflection_dynimage_basic_init to default mono_alc_get_default:

runtime/src/mono/mono/metadata/sre.c

Line 1265 in 82fdd0b

image->image.alc = alc;

When retrieving custom attributes in mono_reflection_get_custom_attrs_by_type_handle, parameter MonoObjectHandle obj seems to be a MonoClass containing an image without ALC. Should the MonoObjectHandle's image contain the ALC?

I wonder if this is because dynamic assemblies have two images - one for the assembly, and one for the image. (this is some old legacy stuff from how the SRE api works). Maybe only the assembly image has an ALC set, but the module image does not? I think the emitted class gets assigned to the module image.

[kotlarmilos]

I wonder if this is because dynamic assemblies have two images - one for the assembly, and one for the image. (this is some old legacy stuff from how the SRE api works). Maybe only the assembly image has an ALC set, but the module image does not? I think the emitted class gets assigned to the module image.

Thanks for pointing out, the module's image ALC wasn't set.

Is there anything we can do to retrieve the image from the assembly, instead of creating a new one for the module?
https://github.com/dotnet/runtime/blob/64243bbf5e9ee53c0c4c5678f2cd8c7f1c9b4f6f/src/mono/mono/metadata/sre.c#L1286C4-L1291

[lambdageek]

Is there anything we can do to retrieve the image from the assembly, instead of creating a new one for the module?

I haven't thought about it on a while, but I think I convinced myself that it's a consequence of how the SRE public API works and there's no way to avoid it without a bunch of hacks. But maybe it's with another look

[srxqds]

why this pr not merged to release/8.0?

[kotlarmilos]

/backport to release/8.0

[github-actions]

Started backporting to release/8.0: https://github.com/dotnet/runtime/actions/runs/5935192228