[PATCH] D98686: [lld:elf] Weaken the requirement for a computed binding to be STB_LOCAL

[Nathan Lanza via Phabricator via llvm-commits]

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In https://reviews.llvm.org/D77280 the test for `isDefined` was added to
account for lazy symbols (e.g. __udivid3) but `isDefined` also includes
anything `external`.

The motivating case here is:

  a.cpp:
  
  struct Animal { virtual void makeNoise() = 0; };
  struct Cat : public Animal { virtual void makeNoise() override; };
  void Cat::makeNoise() { puts("hi"); }
  
  b.cpp
  struct Animal { virtual void makeNoise() = 0; };
  struct Cat : public Animal { virtual void makeNoise() override; };
  void doThingWithCat(Cat *c) { c->makeNoise(); }
  
  version.exp
  {
      global:
        _Z12doThingWithCat3Cat;
      local:
        *;
  }

b.cpp being part of the link causes the vtbl for `_ZTV3Cat` to be
`STB_GLOBAL` since it's `external`.

Changing the test here to be `!isLocal` lets the version-script win.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98686

Files:
  lld/ELF/Symbols.cpp


Index: lld/ELF/Symbols.cpp
===================================================================
--- lld/ELF/Symbols.cpp
+++ lld/ELF/Symbols.cpp
@@ -277,7 +277,7 @@
   if (config->relocatable)
     return binding;
   if ((visibility != STV_DEFAULT && visibility != STV_PROTECTED) ||
-      (versionId == VER_NDX_LOCAL && isDefined()))
+      (versionId == VER_NDX_LOCAL && !isLazy()))
     return STB_LOCAL;
   if (!config->gnuUnique && binding == STB_GNU_UNIQUE)
     return STB_GLOBAL;


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