djtodoro added inline comments.
================
Comment at: llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:984-991
// from one function to another.
if (DD->getDwarfVersion() == 4 && DD->tuneForGDB()) {
assert(PCAddr && "Missing PC information for a call");
addLabelAddress(CallSiteDIE, dwarf::DW_AT_low_pc, PCAddr);
} else if (!IsTail || DD->tuneForGDB()) {
- assert(PCOffset && "Missing return PC information for a call");
- addAddressExpr(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCOffset);
+ assert(PCAddr && "Missing return PC information for a call");
+ addLabelAddress(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCAddr);
----------------
vsk wrote:
> dblaikie wrote:
> > Side question: How'd this end up like this? Why all these GDB tuning
> > checks? Seems like it'd add another layer of complexity/variety that'll
> > make it harder for us to all be evaluating the same things.
> + @djtodoro, I'm not sure why AT_call_return_pc would be needed at a tail
> call site as the debugger must ignore it. As for emitting DW_AT_low_pc under
> gdb tuning, I think this might be an artifact from the original GNU
> implementation.
>I'm not sure why AT_call_return_pc would be needed at a tail call site as the
>debugger must ignore it. As for emitting DW_AT_low_pc under gdb tuning, I
>think this might be an artifact from the original GNU implementation.
Yes, that is the GNU implementation's heritage (I cannot remember why GCC
generated the low_pc info in the case of the tail calls), but GNU GDB needs the
low_pc (as an address) in order to handle the call_site and
call_site_parameters debug info for non-tail calls. To avoiding the pc address
info in the case of tail calls makes sense to me, since debuggers should avoid
that info.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D72489/new/
https://reviews.llvm.org/D72489
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