[llvm] [llvm-symbolizer] Recognize AIX big archive (PR #150401)

[via llvm-commits]

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@@ -557,57 +558,149 @@ 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]() {
-    ObjectPairForPathArch.erase(I);
-  });
+  std::string DbgObjPath = DbgObj->getFileName().str();
+  auto BinIter = BinaryForPath.find(DbgObjPath);
+  if (BinIter != BinaryForPath.end()) {
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midhuncodes7 wrote:

For a plain object file (t.o) the `ModuleName` is "t.o" and `BinaryForPath` also stores an entry keyed by "t.o". `BinaryForPath.find(BinaryName) `succeeds and so is `->second.pushEvictor(...)`.
For an archive member "(t.a(t.o))", `loadOrGetBinary` (and `BinaryForPath.emplace`) is called with the archive path "t.a" (not the "(t.o)" suffix).
But `getOrCreateModuleInfo` still uses `ModuleName` (which is the full "t.a(t.o)") as `BinaryName` when it later does `BinaryForPath.find(BinaryName)`.
That find("t.a(t.o)") returns `end() `(no such key) and when `->second` on that `end()` result — undefined behavior that manifests as a segfault during destructor call.

Updating `BinaryForPath` as "t.a(t.o)" will result in invalid path.
Updating `BinaryName` as "t.a" will result in breaking per-member resolution

Hope this helps

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