[llvm] big archive recognition by the llvm-symbolizer (PR #150401)

[James Henderson via llvm-commits]

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@@ -557,19 +559,101 @@ LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
   if (!DbgObj)
     DbgObj = Obj;
   ObjectPair Res = std::make_pair(Obj, DbgObj);
-  std::string DbgObjPath = DbgObj->getFileName().str();
   auto Pair =
       ObjectPairForPathArch.emplace(std::make_pair(Path, ArchName), Res);
-  BinaryForPath.find(DbgObjPath)->second.pushEvictor([this, I = Pair.first]() {
+  std::string DbgObjPath = DbgObj->getFileName().str();
+  auto BinIter = BinaryForPath.find(DbgObjPath);
+  if (BinIter != BinaryForPath.end()) {
+    BinIter->second.pushEvictor([this, I = Pair.first]() {
     ObjectPairForPathArch.erase(I);
-  });
+    });
+  }
   return Res;
 }
 
+Expected<ObjectFile *> LLVMSymbolizer::getOrCreateObjectFromArchive(StringRef ArchivePath, 
+                                                                    StringRef MemberName, 
+                                                                    const std::string &ArchName) {
+  Binary *Bin = nullptr;
+  auto Pair = BinaryForPath.emplace(ArchivePath.str(), OwningBinary<Binary>());
+  if (!Pair.second) {
+    Bin = Pair.first->second->getBinary();
+    recordAccess(Pair.first->second);
+  } else {
+    Expected<OwningBinary<Binary>> ArchiveOrErr = createBinary(ArchivePath);
+    if (!ArchiveOrErr) {
+      return ArchiveOrErr.takeError();
+    }
+
+    CachedBinary &CachedBin = Pair.first->second;
+    CachedBin = std::move(ArchiveOrErr.get());
+    CachedBin.pushEvictor([this, I = Pair.first]() { BinaryForPath.erase(I); });
+    LRUBinaries.push_back(CachedBin);
+    CacheSize += CachedBin.size();
+    Bin = CachedBin->getBinary();
+  }
+
+  if (!Bin || !isa<object::Archive>(Bin))
+    return errorCodeToError(object_error::invalid_file_type);
+
+  object::Archive *Archive = cast<object::Archive>(Bin);
----------------
jh7370 wrote:

I believe you can use a different cast ([dyn_cast_if_present](https://llvm.org/docs/ProgrammersManual.html#the-isa-cast-and-dyn-cast-templates) maybe?) instead of the `isa` and `cast`.

https://github.com/llvm/llvm-project/pull/150401