[llvm] [clang] [clang-tools-extra] [compiler-rt] [IRPGO][ValueProfile] Instrument virtual table address that could be used to do virtual table address comparision for indirect-call-promotion. (PR #66825)

[Snehasish Kumar via cfe-commits]

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@@ -489,30 +520,66 @@ class InstrProfSymtab {
   /// \p IterRange. This interface is used by IndexedProfReader.
   template <typename NameIterRange> Error create(const NameIterRange &IterRange);
 
-  /// Update the symtab by adding \p FuncName to the table. This interface
-  /// is used by the raw and text profile readers.
-  Error addFuncName(StringRef FuncName) {
-    if (FuncName.empty())
+  /// Create InstrProfSymtab from a set of function names and vtable
+  /// names iteratable from \p IterRange. This interface is used by
+  /// IndexedProfReader.
+  template <typename FuncNameIterRange, typename VTableNameIterRange>
+  Error create(const FuncNameIterRange &FuncIterRange,
+               const VTableNameIterRange &VTableIterRange);
+
+  Error addSymbolName(StringRef SymbolName) {
+    if (SymbolName.empty())
       return make_error<InstrProfError>(instrprof_error::malformed,
-                                        "function name is empty");
-    auto Ins = NameTab.insert(FuncName);
+                                        "symbol name is empty");
+
+    // Insert into NameTab so that MD5NameMap (a vector that will be sorted)
+    // won't have duplicated entries in the first place.
+    auto Ins = NameTab.insert(SymbolName);
     if (Ins.second) {
       MD5NameMap.push_back(std::make_pair(
-          IndexedInstrProf::ComputeHash(FuncName), Ins.first->getKey()));
+          IndexedInstrProf::ComputeHash(SymbolName), Ins.first->getKey()));
       Sorted = false;
     }
     return Error::success();
   }
 
+  /// The method name is kept since there are many callers.
+  /// It just forwards to 'addSymbolName'.
+  Error addFuncName(StringRef FuncName) { return addSymbolName(FuncName); }
+
+  /// Adds VTableName as a known symbol, and inserts it to a map that
+  /// tracks all vtable names.
+  Error addVTableName(StringRef VTableName) {
+    if (Error E = addSymbolName(VTableName))
+      return E;
+
+    // Record VTableName. InstrProfWriter uses this map. The comment around
+    // class member explains why.
+    VTableNames.insert(VTableName);
+    return Error::success();
+  }
+
+  const StringSet<> &getVTableNames() const { return VTableNames; }
+
   /// Map a function address to its name's MD5 hash. This interface
   /// is only used by the raw profiler reader.
   void mapAddress(uint64_t Addr, uint64_t MD5Val) {
     AddrToMD5Map.push_back(std::make_pair(Addr, MD5Val));
   }
 
+  /// Map the address range (i.e., [start_address, end_address]) of a variable to
+  /// its names' MD5 hash. This interface is only used by the raw profile header.
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snehasish wrote:

Did you mean reader instead of header? I didn't follow the last sentence here.

https://github.com/llvm/llvm-project/pull/66825