[clang] [llvm] [InstrProf] Remove PGO name reading and writing (PR #214134)

[Owen Rodley via llvm-commits]

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@@ -558,8 +513,9 @@ Error InstrProfSymtab::addVTableWithName(GlobalVariable &VTable,
       return E;
 
     bool Inserted = true;
-    std::tie(std::ignore, Inserted) = MD5VTableMap.try_emplace(
-        GlobalValue::getGUIDAssumingExternalLinkage(Name), &VTable);
+    uint64_t GUID = VTable.getGUIDIfAssigned().value_or(
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orodley wrote:

I looked at this and the behaviour was actually incorrect. Both `addFuncWithName` and `addVTableWithName` get called multiple times for the same object, once for each name it should be findable by (the deprecated PGO name, the canonical name, etc.). Using the assigned GUID when present put every one of those entries under the same key, so once an object had a GUID it could only be found by that GUID, and lookups by any of its names failed.

Fixed to always hash the given name, and add the assigned GUID as one extra key. That removes this pattern, so I don't think a method is needed. Added tests for both cases.
  

https://github.com/llvm/llvm-project/pull/214134