It was pointed out that posting patches directly to the list is 
preferred over Gerrit, so I abandoned the Gerrit review and I'm 
attaching the patch here. The wiki says a git-format-patch'd attachment 
is OK, but let me know if it isn't the norm!

Scott

On 2020-03-18 16:43, scott@scottlinder.com wrote:
> AMD is working on a port of GDB for our GPUs based on the ROCm stack
> (https://rocm.github.io/). We recently open-sourced the fork at
> https://github.com/ROCm-Developer-Tools/ROCgdb. We hope to begin 
> upstreaming
> patches where possible,
> and https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/767 is the 
> first
> such patch.
> 
> We frequently have functions inlined into the outermost frame. The 
> current
> implementation which introduced `outer_frame_id` as a "valid" ID 
> distinct from
> `null_frame_id` does not support this, asserting the need for both a 
> valid
> and non-`outer_frame_id` ID to base the ID of the inlined frame on.
> 
> This patch changes the definition of `outer_frame_id` slightly to 
> effectively
> represent a class of IDs which identify a frame inlined into the outer 
> frame.
> These differ in `artificial_depth`, but otherwise behave just as
> `outer_frame_id` in that they are `FID_STACK_INVALID`, yet `frame_id_p` 
> returns
> `true` and they compare equal to each other.
> 
> Running the testsuite both with and without the patch doesn't yield any 
> obvious
> regressions, although I have not come up with a test case to prove this 
> out on
> e.g. x86.
> 
> Does this seem reasonable? It is a bit of a hack on a hack, considering 
> the
> existing issues with `outer_frame_id` and the obvious desire to remove 
> it
> completely. At the same time, there is a fair amount of thought and 
> effort
> involved in making that change, and I think it can/should be done 
> independently
> of fixing this bug. My feeling is this patch is a pretty non-invasive 
> change
> that doesn't make the situation fundamentally worse, but any feedback 
> is
> appreciated.
> 
> Cheers,
> Scott