[PATCH] D37570: [XRay][CodeGen][PowerPC] Fix tail exit codegen for XRay in PPC

[Tim Shen via Phabricator via llvm-commits]

timshen added inline comments.


================
Comment at: lib/CodeGen/XRayInstrumentation.cpp:118
-      }
-      if (TII->isTailCall(T)) {
-        Opc = TargetOpcode::PATCHABLE_TAIL_CALL;
----------------
dberris wrote:
> timshen wrote:
> > dberris wrote:
> > > timshen wrote:
> > > > This is actively removing PATCHABLE_TAIL_CALL emits, and it affects all architectures.
> > > > 
> > > > Can we add x86 tests for tracking the decisions we've made?
> > > Note that this function only gets called for non-X86 architectures (where prepending is the correct solution).
> > > 
> > > We already have tests in X86 for the tail call exit sled lowering. Those pass with this change.
> > We have other non-x86 targets like aarch64, right? How do those targets test this?
> Yes, we have the following tests aside from the ones we're adding here.
> 
> ```
> test/CodeGen/ARM/xray-tail-call-sled.ll
> test/CodeGen/AArch64/xray-tail-call-sled.ll
> ```
> 
> Or did you mean we need a test for tail calls out to hidden/external functions?
What does "out to" mean?

Yes. I was surprised that aarch64 tests are not affected by this patch. I guess that tests are missing and we should add them, but my guess can be wrong?


https://reviews.llvm.org/D37570