[PATCH] D78952: [LangRef] Describe linkage types, allocation size of declarations for global variables

[Matthias Schiffer via Phabricator via llvm-commits]

NeoRaider added a comment.

In D78952#2006342 <https://reviews.llvm.org/D78952#2006342>, @efriedma wrote:

> 1. Global variables are not allowed to overlap.  (This follows from the pointer aliasing rules.)


Makes sense, I'll add this.

> 2. The alignment does have to match the declared alignment.  And the "declared" alignment is implicitly computed based on the type if it isn't explicitly specified.

Question regarding alignment: I would expect that a variable declaration with lower alignment than the definition it refers to should be fine. For example, when declaring an extern global variable of a forward-declared struct type in C, clang will use an opaque type with alignment 1 for the declaration.


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