[clang] [compiler-rt] [llvm] [TypeProf][InstrFDO]Implement more efficient comparison sequence for indirect-call-promotion with vtable profiles. (PR #81442)

[Mingming Liu via cfe-commits]

================
@@ -341,6 +879,17 @@ static bool promoteIndirectCalls(Module &M, ProfileSummaryInfo *PSI, bool InLTO,
     return false;
   }
   bool Changed = false;
+  VirtualCallSiteTypeInfoMap VirtualCSInfo;
+
+  computeVirtualCallSiteTypeInfoMap(M, MAM, VirtualCSInfo);
+
+  // This map records states across functions in an LLVM IR module.
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minglotus-6 wrote:

`VTableAddressPointOffsetVal` stores the vtable address points. The vtable address point of a given `<vtable, address point offset>` is static (doesn't change after being computed once).

`IndirectCallPromoter::getOrCreateVTableAddressPointVar` creates the map entry the first time a `<vtable, offset>` pair is seen,  as `promoteIndirectCalls`  processes an IR module and calls `IndirectCallPromoter` repeatedly on each function.

I reworded the comments. PTAL.


https://github.com/llvm/llvm-project/pull/81442