[Wasm] AOT support for threading-enabled runtime

[jeromelaban]

Description

Building AOT images with threading enabled is failing.

Reproduction Steps

When building AOT images with threading enabled, the following lines:

runtime/src/mono/wasm/runtime/driver.c

Lines 479 to 482 in 3d74b00

	#ifndef DISABLE_THREADS
	monoeg_g_setenv ("MONO_THREADS_SUSPEND", "coop", 0);
	monoeg_g_setenv ("MONO_SLEEP_ABORT_LIMIT", "5000", 0);
	#endif

cause the following error:

`not compiled with safepoints`

@lambdageek mentioned that the environment needs to have MONO_THREADS_SUSPEND=coop set before invoking the compiler, but the compilation fails with the following:

* Assertion at /__w/Uno.DotnetRuntime.WebAssembly/Uno.DotnetRuntime.WebAssembly/runtime/src/mono/mono/mini/mini.c:2752, condition `mini_safepoints_enabled ()' not met

runtime/src/mono/mono/mini/mini.h

Lines 2931 to 2937 in e3a4db9

	mini_safepoints_enabled (void)
	{
	#if defined (TARGET_WASM)
	return FALSE;
	#else
	return TRUE;
	#endif

Expected behavior

Compilation succeeds.

Actual behavior

See above.

Regression?

No

Known Workarounds

None

Configuration

213b4d4

Other information

No response

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[ghost]

Tagging subscribers to 'arch-wasm': @lewing
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Building AOT images with threading enabled is failing.

Reproduction Steps

When building AOT images with threading enabled, the following lines:

runtime/src/mono/wasm/runtime/driver.c

Lines 479 to 482 in 3d74b00

	#ifndef DISABLE_THREADS
	monoeg_g_setenv ("MONO_THREADS_SUSPEND", "coop", 0);
	monoeg_g_setenv ("MONO_SLEEP_ABORT_LIMIT", "5000", 0);
	#endif

cause the following error:

`not compiled with safepoints`

@lambdageek mentioned that the environment needs to have MONO_THREADS_SUSPEND=coop set before invoking the compiler, but the compilation fails with the following:

* Assertion at /__w/Uno.DotnetRuntime.WebAssembly/Uno.DotnetRuntime.WebAssembly/runtime/src/mono/mono/mini/mini.c:2752, condition `mini_safepoints_enabled ()' not met

runtime/src/mono/mono/mini/mini.h

Lines 2931 to 2937 in e3a4db9

	mini_safepoints_enabled (void)
	{
	#if defined (TARGET_WASM)
	return FALSE;
	#else
	return TRUE;
	#endif

Expected behavior

Compilation succeeds.

Actual behavior

See above.

Regression?

No

Known Workarounds

None

Configuration

213b4d4

Other information

No response

Author:	jeromelaban
Assignees:	-
Labels:	arch-wasm, untriaged
Milestone:	-

[lambdageek]

Ideally we can produce a single mono-aot-cross AOT compiler that is usable for wasm with and without threading. So we shoudl get rid of #ifdef paths and replace them with an aot compiler flag to decide if we're targeting a threaded runtime.

Another thing the flag could control is whether LLVM is allowed to use post-MVP atomics opcodes

[lewing]

@vargaz did #70520 resolve this fully?

[jeromelaban]

@lewing This issue was using a similar change in the runtime (with safe point enabled) and it is still present.

[radical]

@kg should this be moved to 8.0?

[kg]

I think so.

[lambdageek]

I think we're done here, actually. The AOT compiler now has a --wasm-gc-safepoints and the Wasm SDK now passes it automatically by default when the WasmEnableThreads property is true.

demo: https://lambdageek.dev/dotnet-wasm-raytracer/ (AOT+SIMD+threads)