[PATCH] D108413: [lld][WebAssembly] Handle weakly defined symbols in shared libraries.

[Sam Clegg via Phabricator via llvm-commits]

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In the case of weakly defined symbols in shared libraries we now
generate both an import and an export.  The dynamic linker can then
choose how a winner from amount all the shared libraries that defined a
given symbol.

Previously any direct usage of a weakly defined symbol would use the
DSO-local definition (For example, even through there would be single
address for a weakly defined function, each DSO could end up directly
calling its local version).

Fixes: https://github.com/emscripten-core/emscripten/issues/13773


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D108413

Files:
  lld/test/wasm/shared-weak-symbols.s
  lld/wasm/Symbols.cpp
  lld/wasm/Symbols.h
  lld/wasm/SyntheticSections.cpp
  lld/wasm/Writer.cpp

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