[PATCH] D135914: [PseudoProbe] Decode offset based pseudo probe.

[Hongtao Yu via Phabricator via llvm-commits]

hoy added a comment.

In D135914#3881607 <https://reviews.llvm.org/D135914#3881607>, @wenlei wrote:

> Sentinel probe case isn't covered for both encoding and decoding in any test cases, would be good to have some coverage.

Forgot to mention that the updated binary, i.e, inline-cs-pseudoprobe.perfbin, is built with the new encoding. The binary supports a dozen llvm-profgen tests and they all pass with the current decoding changes.



================
Comment at: llvm/lib/MC/MCPseudoProbe.cpp:418
   // Decide if top-level node should be disgarded.
-  if (Cur == &DummyInlineRoot && !GuildFilter.empty() &&
-      !GuildFilter.count(Guid))
+  if (Cur == &DummyInlineRoot && !GuidFilter.empty() && !GuidFilter.count(Guid))
     Cur = nullptr;
----------------
wenlei wrote:
> nit: `Cur == &DummyInlineRoot` -> `IsTopLevelFunc`
Done.


================
Comment at: llvm/lib/MC/MCPseudoProbe.cpp:476
+        // leading probe address or function start address.
+        EncodingIsAddrBased = true;
+      }
----------------
wenlei wrote:
> Maybe I'm asking the same question as the one on previous patch, but why do we still have cases with absolute address encoded? I thought for main function body we have GUID -> symbol (reverse lookup) -> address; and we have similar way to get address for sentinel for split binary function. The rest should all be offset/delta.
This is mainly for downwards-compatibility, i.e. to have new llvm-profgen handle old binaries. 


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https://reviews.llvm.org/D135914