[PATCH] D34138: [LLD][ELF] make default for get{ARM, AArch64}UndefinedRelativeWeakVA unreachable

[Rui Ueyama via Phabricator via llvm-commits]

ruiu added inline comments.


================
Comment at: ELF/InputSection.cpp:405-406
   switch (Type) {
+  // Unresolved branch relocations to weak references resolve to next
+  // instruction.
   case R_ARM_THM_JUMP11:
----------------
peter.smith wrote:
> ruiu wrote:
> > What does this comment explain?
> In the ARM ABI there is a general rule for handling pc-relative relocations. There is a further special case for the subset of pc-relative instructions that are also branch relocations. I wanted to explain why the branch relocations resolved to the address of the next instruction, but the other relocations did not.
> 
> I'll update the comments to make this more explicit.
Thank you for adding the explanation.

So, does this comment explain `return P + 2 + A`? I'd move this after `case` instead of writing it before `case`.


================
Comment at: ELF/InputSection.cpp:425
     return P + 5 + A;
-  default:
+  // Unresolved non branch pc-relative relocations
+  // R_ARM_TARGET2 which can be resolved relatively is not present as it never
----------------
Move this after the last `case` too.


https://reviews.llvm.org/D34138