sunfish added inline comments.

================
Comment at: llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp:1279
+  if (const GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op))
+    return WebAssembly::isManagedAddressSpace(GA->getAddressSpace());
+
----------------
sbc100 wrote:
> sunfish wrote:
> > tlively wrote:
> > > tlively wrote:
> > > > Actually, should we enforce that these LLVM IR globals be thread_local, 
> > > > since the resulting Wasm globals will be thread_local? I don't know if 
> > > > that will affect any optimizations, but it seems like a more accurate 
> > > > modeling. If we do that, 
> > > > `CoalesceLocalsAndStripAtomics::stripThreadLocals` in 
> > > > WebAssemblyTargetMachine.cpp will have to be updated to not strip the 
> > > > thread locals corresponding to Wasm globals.
> > > I'd be fine handling this in a follow-up if you want to get this landed.
> > Note that this will be true of Worker-based threads, but not of the 
> > expected future "wasm native threads". I wonder if this means that 
> > clang/llvm will (eventually) need to be aware of this difference.
> Don't you think is very likely that even in "wasm native threads" we would 
> want to opt into sharing like we do with wasm memories?   That path would 
> seem better for compatibility with existing worker-based threading.  
> 
> Obviously once we do have shared wasm globals we will need to modify llvm's 
> assumptions, but for now I think it is a reasonable assumption/assertion that 
> wasm globals are TLS.
Yeah, I agree we'll likely want some way to opt into sharing. So the difference 
here is, worker-based threads won't have the option of sharing, so maybe 
requiring `thread_local` makes sense. But native threads could opt into 
sharing, so they could be `thread_local` or not.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101608/new/

https://reviews.llvm.org/D101608

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