[LLVMdev] indirectbr across function boundaries

[Alexander Bernauer]

Hi

according to [1] and [2] the blockaddress of any basic block can be
obtained.

But I am not sure about that fact that an indirectbr can only target at
a basic block which is within the same function as the indirectbr instruction.

[1] states:
---8<---
All possible destination blocks must be listed in the label list,
otherwise this instruction has undefined behavior. This implies that
jumps to labels defined in other functions have undefined behavior as
well.
--->8---

I don't understand this implication. And what exactly is meant by "other
functions"? Can anybody clearify this?

I just want to make sure cross-function branches are really impossible.

thanks

regards

Alex

[1] http://llvm.org/docs/LangRef.html#blockaddress
[2] http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html

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