[PATCH 3/6] Allow jumps in epilogues

[Bernd Schmidt]

On 03/23/2011 06:19 PM, Richard Henderson wrote:
> In general, with shrink-wrapping, we can have essentially arbitrary
> differences in unwind info between blocks that are sequential.

So, while that isn't the case just yet with the current shrink-wrapping
patch, it seems I will either have to make dwarf2out fully general, or
ensure that basic blocks occur in only a certain order (the prologue
must be written out only after all basic blocks that can be executed
before or without reaching it).

I don't know much about the unwinding code. I'm currently thinking about
writing out a cfi_remember_state at the start of the function, restoring
that clean state when necessary at the start of a new block and emitting
the necessary directives to reach the correct state. What directives
should I expect to be required? Can I get by just with cfi_offset and
cfi_def_cfa_offset, or will something else be necessary?


Bernd