eddyz87 added inline comments.
================
Comment at: clang/lib/CodeGen/CGExpr.cpp:3791
+ if (hasBPFPreserveStaticOffset(Base))
+ addr = wrapWithBPFPreserveStaticOffset(CGF, addr);
+
----------------
ast wrote:
> eddyz87 wrote:
> > ast wrote:
> > > eddyz87 wrote:
> > > > ast wrote:
> > > > > If I'm reading this correctly wrapping with preserve_static_offset
> > > > > doesn't prevent further preserver_access_index wrapping which is a
> > > > > wasted effort for pai at the end ?
> > > > Yes, pai calls are undone in
> > > > `BPFPreserveStaticOffset.cpp:removePAICalls()`. I can put back the
> > > > logic that suppresses pai if preserve static offset is present.
> > > I see. I guess I missed a previous discussion. Why this approach was
> > > chosen?
> > Initial version used `__attribute__((btf_decl_tag("ctx")))` and Yonghong
> > did not want to have prioritization between `btf_decl_tag` and
> > `preserve_access_index` basing on decl tag string parameter. Now this
> > limitation is gone (and I think this was one of your arguments in favor of
> > separate attribute).
> Ahh. Right. It made sense to avoid special treatment of strings in decl_tag,
> but now it's gone and PSO takes precedence over PAI. Here we're adding PAI
> just to remove it later. Looks like a waste of cpu cycles and code. Unless
> applying PAI to outer struct and PSO in inner makes implementation tricky. I
> doubt we need to support such combo though. I'm fine cleaning this up in a
> follow up. If such cleanup makes sense at all.
> If such cleanup makes sense at all.
I think it does, I'll implement this change and push an update.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D133361/new/
https://reviews.llvm.org/D133361
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