Update mimalloc to 2.1.7

[kleisauke]

No description provided.

[sbc100]

Oh, I guess we should make __builtin_thread_pointer work. I've not seen that before.

[sbc100]

Could you open an upsteam llvm issue regarding fatal error: error in backend: Cannot select: intrinsic %llvm.thread.pointer ?

[kripken]

Thanks!

Should we wait until dev-slice lands in their main branch? I would guess that would be when they consider it stable, but I don't actually know their dev practices.

[kripken]

Did the emmalloc alignment limitations get fixed?

[kleisauke]

This was fixed via PR #21905 in the meantime. I also removed MIN_EMMALLOC_ALIGN initially, but let's leave that for now.

[kleisauke]

Revised this PR to update mimalloc to 2.1.7 instead. This is ready for review now.

Could you open an upsteam llvm issue regarding fatal error: error in backend: Cannot select: intrinsic %llvm.thread.pointer ?

I just opened issue llvm/llvm-project#117433 for this. Commit 0dc7223 defines MI_LIBC_MUSL to workaround this.

[sbc100]

I'm not sure we want a FIXME here since we are using musl as our libc so this seems correct in any case.

[kleisauke]

a090ba8

[kripken]

Suggested change

	# disable `assert()` in emmalloc
	# disable `assert()` in mimalloc

But do we not want this in debug builds?

[sbc100]

If we do, I think that we can/should make that a separate change.

[kleisauke]

I think the comment is correct in this case, mimalloc uses mi_assert, which is already disabled.

emscripten/system/lib/mimalloc/include/mimalloc/types.h

Lines 563 to 569 in a090ba8

	#if (MI_DEBUG)
	// use our own assertion to print without memory allocation
	void _mi_assert_fail(const char* assertion, const char* fname, unsigned int line, const char* func );
	#define mi_assert(expr) ((expr) ? (void)0 : _mi_assert_fail(#expr,__FILE__,__LINE__,__func__))
	#else
	#define mi_assert(x)
	#endif

However, we also want to disable the assertions in the underlying emmalloc allocator, which we build as part of mimalloc:

emscripten/tools/system_libs.py

Lines 1818 to 1819 in a090ba8

	# Build all of mimalloc, and also emmalloc which is used as the system
	# allocator underneath it.

emscripten/tools/system_libs.py

Line 1828 in a090ba8

src_files += [utils.path_from_root('system/lib/emmalloc.c')]

emscripten/system/lib/emmalloc.c

Lines 33 to 35 in a090ba8

	* Debugging:
	*
	* - If not NDEBUG, runtime assert()s are in use.

emscripten/system/lib/libc/musl/include/assert.h

Lines 5 to 9 in a090ba8

	#ifdef NDEBUG
	#define assert(x) (void)0
	#else
	#define assert(x) ((void)((x) || (__assert_fail(#x, __FILE__, __LINE__, __func__),0)))
	#endif

[kripken]

Oh, it's for the underlying allocator. In that case it sounds ok. But can it be a separate change, or was it necessary for some reason to do in this PR?

[kleisauke]

There's no specific reason to address it in this PR; it was discovered by accident while working on this. Split into PR #23016.

[kripken]

Thanks @kleisauke !