[llvm] [BOLT] Add support for safe-icf (PR #116275)

[Maksim Panchenko via llvm-commits]

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@@ -39,20 +39,29 @@ class IdenticalCodeFolding : public BinaryFunctionPass {
     All,  // Aggressive ICF for code.
   };
   explicit IdenticalCodeFolding(const cl::opt<bool> &PrintPass)
-      : BinaryFunctionPass(PrintPass) {}
+      : BinaryFunctionPass(PrintPass) {
+    VtableBitVector.resize((((uint64_t)1) << 32) / 8);
+  }
 
   const char *getName() const override { return "identical-code-folding"; }
   Error runOnFunctions(BinaryContext &BC) override;
 
 private:
+  /// Bit vector of memory addresses of vtables.
+  llvm::BitVector VtableBitVector;
+  bool isInVTable(uint64_t Address) const {
+    return VtableBitVector.test(Address / 8);
+  }
+  /// Scans symbol table and creates a bit vector of memory addresses of
+  /// vtables.
+  void processSymbolTable(const BinaryContext &BC);
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maksfb wrote:

`initVTableReferences()`?

https://github.com/llvm/llvm-project/pull/116275