Update LLVM (#4530)

Includes updates to reflect these LLVM changes:
* https://github.com/llvm/llvm-project/pull/112517
* https://github.com/llvm/llvm-project/pull/113331

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>

MODULE.bazel

@@ -139,8 +139,8 @@ bazel_dep(name = "zstd", version = "1.5.6", repo_name = "llvm_zstd")
 
 # We pin to specific upstream commits and try to track top-of-tree reasonably
 # closely rather than pinning to a specific release.
-# HEAD as of 2024-10-17.
-llvm_project_version = "5033ea73bb01061feb09b3216c74619e1fbefdeb"
+# HEAD as of 2024-11-13.
+llvm_project_version = "97298853b4de70dbce9c0a140ac38e3ac179e02e"
 
 # Load a repository for the raw llvm-project, pre-overlay.
 http_archive(
@@ -151,7 +151,7 @@ http_archive(
         "@carbon//bazel/llvm_project:0001_Patch_for_mallinfo2_when_using_Bazel_build_system.patch",
         "@carbon//bazel/llvm_project:0002_Added_Bazel_build_for_compiler_rt_fuzzer.patch",
     ],
-    sha256 = "9964d7643f3cb1cfabde913b747a2fa2524c469adc847fceee4dd883dbc0482a",
+    sha256 = "ac811cb61d281043c865c39260a5114a0e96d16ec0e4eb74a2516a24981b9064",
     strip_prefix = "llvm-project-{0}".format(llvm_project_version),
     urls = ["https://github.com/llvm/llvm-project/archive/{0}.tar.gz".format(llvm_project_version)],
 )

toolchain/driver/clang_runner.cpp

@@ -123,7 +123,8 @@ auto ClangRunner::Run(llvm::ArrayRef<llvm::StringRef> args) -> bool {
   clang::DiagnosticsEngine diagnostics(
       diagnostic_ids_, diagnostic_options.get(), &diagnostic_client,
       /*ShouldOwnClient=*/false);
-  clang::ProcessWarningOptions(diagnostics, *diagnostic_options);
+  auto vfs = llvm::vfs::getRealFileSystem();
+  clang::ProcessWarningOptions(diagnostics, *diagnostic_options, *vfs);
 
   clang::driver::Driver driver(clang_path, target_, diagnostics);
 

toolchain/lower/file_context.cpp

@@ -228,7 +228,8 @@ auto FileContext::BuildFunctionDecl(SemIR::FunctionId function_id,
   param_inst_ids.reserve(max_llvm_params);
   auto return_param_id = SemIR::InstId::Invalid;
   if (return_info.has_return_slot()) {
-    param_types.push_back(return_type->getPointerTo());
+    param_types.push_back(
+        llvm::PointerType::get(return_type, /*AddressSpace=*/0));
     return_param_id = sem_ir()
                           .insts()
                           .GetAs<SemIR::ReturnSlot>(function.return_slot_id)