[llvm] [SampleFDO][TypeProf]Support vtable type profiling for ext-binary and text format (PR #148002)

[David Li via llvm-commits]

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@@ -318,16 +324,28 @@ struct LineLocationHash {
 
 LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const LineLocation &Loc);
 
+/// Key represents the id of a vtable and value represents its count.
+/// TODO: Rename class FunctionId to SymbolId in a separate PR.
+using TypeCountMap = std::map<FunctionId, uint64_t>;
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david-xl wrote:

Add document on FunctionId/SymbolId which refers to vtable symbol. 'Type' refers to C++ polymorphic class types.

https://github.com/llvm/llvm-project/pull/148002