Noticed in code review
4318028cd2 (commitcomment-57738034)
But the issue had already been fixed in
943b304848 due to a code checking tool
(PVS studio) identification, but that lacked test coverage.
Refactor this test a little bit too by using more CHECK-SAME to help the
checks fail sooner (rather than, if the addrx or sizes are wrong, having
that check bind to a much later output line - and then fail due to the
implicit-check-nots, which don't provide a lot of information about
where the intended check was likely to land) & more informatively.
Also modify the test to be more robust (current IR generation doesn't
include call sites for callees that are only declared but not defined -
so the test case couldn't be regenerated - add a function definition (&
optnone attribute) so it doesn't depend on call sites for
declared-but-not-defined functions)
Experimental, using non-existent DWARF support to use an expr for the
location involving an addr_index (to compute address + offset so
addresses can be reused in more places).
The global variable debug info had to be deferred until the end of the
module (so bss variables would all be emitted first - so their labels
would have the relevant section). Non-bss variables seemed to not have
their label assigned to a section even at the end of the module, so I
didn't know what to do there.
Also, the hashing code is broken - doesn't know how to hash these
expressions (& isn't hashing anything inside subprograms, which seems
problematic), so for test purposes this change just skips the hash
computation. (GCC's actually overly sensitive in its hash function, it
seems - I'm forgetting the specific case right now - anyway, we might
want to just use the frontend-known file hash and give up on optimistic
.dwo/.dwp reuse)
Given the ability provided by DWARFv5 rnglists to reuse addresses in the
address pool, it can be advantageous to object file size to use range
encodings even when the range could be described by a direct low/high
pc.
Add a flag to allow enabling this in DWARFv5 for the purpose of
experimentation/data gathering.
It might be that it makes sense to enable this functionality by default
for DWARFv5 + Split DWARF at least, where the tradeoff/desire to
optimize for .o file size is more explicit and .o bytes are higher
priority than .dwo bytes.
David Blaikie