Remove pointer relocs from GC statics

[MichalStrehovsky]

For every type with a GC static base (i.e. something with static fields that contain references to the GC heap) we are generating a small data structure that has up to two pointers in it:

• The first pointer points to a fake MethodTable that is used to allocate the static base on the GC heap (and assists in reporting GC pointers within that data).
• The second pointer potentially points to data that was generated when interpreting the .cctor and gets memcopied to the GC static base at startup

These pointers can be relative pointers, so I'm doing that. Saves about 2 kB on a hello world on Windows. The savings will be closer to 0.5% on Linux due to getting rid of the full pointers (each costs extra 24 bytes on Linux).

Cc @dotnet/ilc-contrib

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Issue Details

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For every type with a GC static base (i.e. something with static fields that contain references to the GC heap) we are generating a small data structure that has up to two pointers in it:

• The first pointer points to a fake MethodTable that is used to allocate the static base on the GC heap (and assists in reporting GC pointers within that data).
• The second pointer potentially points to data that was generated when interpreting the .cctor and gets memcopied to the GC static base at startup

These pointers can be relative pointers, so I'm doing that. Saves about 2 kB on a hello world on Windows. The savings will be closer to 0.5% on Linux due to getting rid of the full pointers (each costs extra 24 bytes on Linux).

Cc @dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	MichalStrehovsky
Labels:	area-NativeAOT-coreclr
Milestone:	-

[jkotas]

Nice!