[mono][interp] implement interp bitcast intrinsics

[lewing]

based on #103915

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[BrzVlad]

Don't understand why the type matters. Sounds like we should just emit MINT_MOV_4 or MINT_MOV_8.

[lewing]

I really did just extract the changes from the linked pr and try to get them working as a first step. I think the intent was to make sure the jiterp sees the reinterpret but I'm not sure it matters in a practical sense?

cc @kg

[lewing]

[21:53:51] fail: [MONO] MemoryExtensions.IndexOfAnyInRange: Store local stack type mismatch 1 5
Error
    at Pc (http://127.0.0.1:49275/_framework/dotnet.runtime.js:3:171796)
    at wasm_trace_logger (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[159]:0xb288)
    at eglib_log_adapter (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[655]:0x455c6)
    at monoeg_g_logv_nofree (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[580]:0x436bb)
    at monoeg_g_log (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[582]:0x4377e)
    at store_local (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[365]:0x2b83e)
    at generate_code (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[362]:0x2365a)
    at interp_inline_method (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[417]:0x3c6bc)
    at interp_transform_call (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[373]:0x2cc80)
    at generate_code (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[362]:0x24a51)
    at mono_interp_transform_method (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[405]:0x30dfb)
    at tier_up_method (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[467]:0x401af)
    at mono_interp_exec_method (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[213]:0x1a62a)
    at interp_runtime_invoke (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[256]:0x1e1d4)
    at mono_jit_runtime_invoke (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[3236]:0xf9328)
    at do_runtime_invoke (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[2559]:0xcd12e)
    at mono_runtime_invoke_checked (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[2558]:0xcd0b3)
    at ves_icall_InternalInvoke_raw (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[1912]:0xa59a7)
    at do_icall (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[297]:0x20186)
    at do_icall_wrapper (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[222]:0x1d344)
    at mono_interp_exec_method (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[213]:0xf1ca)
    at interp_entry (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[290]:0x1fb83)
    at interp_entry_static_0 (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[326]:0x20d29)
    at wasm_native_to_interp_System_Private_CoreLib_System_Threading_ThreadPool_BackgroundJobHandler (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[185]:0xca2e)
    at mono_background_exec (http://127.0.0.1:49275/_framework/dotnet.native.wasm:wasm-function[797]:0x4a99e)
    at e.<computed> (http://127.0.0.1:49275/_framework/dotnet.runtime.js:3:183072)
    at Zo (http://127.0.0.1:49275/_framework/dotnet.runtime.js:3:56689)
    at callUserCallback (http://127.0.0.1:49275/_framework/dotnet.native.js:8:106543)
    at http://127.0.0.1:49275/_framework/dotnet.native.js:8:106811

[lewing]

this will also help reduce the impact of #116221

[lewing]

@kg @BrzVlad I'm happy to finish this up if I can get some guidance on the correct direction.

[BrzVlad]

At this point we have the size. I imagine we should just do the following:

if (size <= 4)
    add_ins (MINT_MOV_4);
else if (size <= 8)
    add_ins (MINT_MOV_8);
else
    add_ins (MINT_MOV_VT);

[BrzVlad]

The bug in your code is that here you are always pushing a VT type on the stack, where you could actually have a primitive type since you could cast a valuetype (of size 8) to an int64 for example. If you use the suggestion from above this should no longer be a problem.