[PATCH] D75277: [WebAssembly] Remove restriction on main name mangling

[Sam Clegg via Phabricator via cfe-commits]

sbc100 added inline comments.


================
Comment at: clang/lib/CodeGen/CodeGenModule.cpp:6360
+      auto *GA = llvm::GlobalAlias::create("__main_void", F);
+      GA->setVisibility(F->getVisibility());
+    }
----------------
sbc100 wrote:
> sunfish wrote:
> > sbc100 wrote:
> > > sunfish wrote:
> > > > Can this use `GA->setVisibility(GlobalValue::HiddenVisibility)`? `__main_void` is an implementation detail, so in theory users shouldn't be setting interesting visibility attributes on it.
> > > The caller main / __main_void could live in different shared library the main function itself.  
> > > 
> > > IIRC the caller of `main` is normally something like crt1.o and it should be able to see `__main_void` if, and only if, it can see `main`.  i.e. if should have the same visibility as main itself, no?
> > Typically crt1.o is linked into the same exe/dso as `main`, so it needs `main` to have external linkage, but it doesn't need `main` to have any particular visibility.
> > 
> > In Emscripten, is `main` being called from a different dso, or from JS following visibility rules for different dsos?
> No, emscirpten is not different that respect.   Typically main lives in the same DSO as crt1.o.   
> 
> But it doesn't have to, and we have a few tests that check it can be in a separate dso.
Actually I think verified that setting this to hidden works for emscripten (at least the tests pass).

@sunfish.. do you know if you were relying on this symbols being marked as "used"?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75277/new/

https://reviews.llvm.org/D75277