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

[Maksim Panchenko via llvm-commits]

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@@ -341,6 +341,61 @@ typedef std::unordered_map<BinaryFunction *, std::vector<BinaryFunction *>,
 namespace llvm {
 namespace bolt {
 
+Error IdenticalCodeFolding::processDataRelocations(
+    BinaryContext &BC, const SectionRef &SecRefRelData) {
+  for (const RelocationRef &Rel : SecRefRelData.relocations()) {
+    symbol_iterator SymbolIter = Rel.getSymbol();
+    const ObjectFile *OwningObj = Rel.getObject();
+    assert(SymbolIter != OwningObj->symbol_end() &&
+           "relocation Symbol expected");
+    const SymbolRef &Symbol = *SymbolIter;
+    const uint64_t SymbolAddress = cantFail(Symbol.getAddress());
+    const ELFObjectFileBase *ELFObj = dyn_cast<ELFObjectFileBase>(OwningObj);
+    if (!ELFObj)
+      return createFatalBOLTError(
+          Twine("BOLT-ERROR: Only ELFObjectFileBase is supported"));
+    const int64_t Addend = getRelocationAddend(ELFObj, Rel);
+    BinaryFunction *BF = BC.getBinaryFunctionAtAddress(SymbolAddress + Addend);
+    if (!BF)
+      continue;
+    BF->setUnsafeICF();
+  }
+  return Error::success();
+}
+
+Error IdenticalCodeFolding::markFunctionsUnsafeToFold(BinaryContext &BC) {
+  ErrorOr<BinarySection &> SecRelData = BC.getUniqueSectionByName(".rela.data");
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maksfb wrote:

I don't understand why the processing is limited to `.rela.data`.

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