[PATCH] D26045: [cfi] Fix weak functions handling.

[Evgeniy Stepanov via llvm-commits]

eugenis created this revision.
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When a function pointer is replaced with a jumptable pointer, special
case is needed to preserve the semantics of extern_weak functions.
Since a jumptable entry can not be extern_weak, we emulate that
behaviour by replacing all references to F (the extern_weak function)
with the following expression: F != nullptr ? JumpTablePtr : nullptr.

Extra special care is needed for global initializers, since most (or
probably all) backends can not lower an initializer that includes
this kind of constant expression. Initializers like that are replaced
with a global constructor (i.e. a runtime initializer).


Repository:
  rL LLVM

https://reviews.llvm.org/D26045

Files:
  lib/Transforms/IPO/LowerTypeTests.cpp
  test/Transforms/LowerTypeTests/function-weak.ll

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