[clang] [llvm] [clang] Allow enabling sandbox for direct `-cc1` invocations (PR #174653)

[Ben Langmuir via cfe-commits]

================
@@ -264,8 +265,10 @@ int clang_main(int Argc, char **Argv, const llvm::ToolContext &ToolContext) {
   }
 
   // Handle -cc1 integrated tools.
-  if (Args.size() >= 2 && StringRef(Args[1]).starts_with("-cc1"))
+  if (Args.size() >= 2 && StringRef(Args[1]).starts_with("-cc1")) {
+    auto EnableSandbox = llvm::sys::sandbox::scopedEnable();
----------------
benlangmuir wrote:

For some reason I thought you reverted the change to handle this in CC1Command, which is why I thought we were missing a case. 

Your point about crash recovery is convincing, so I suggest for now at least we just add a comment here to say that the integrated cc1 is handled in `CC1Command::Execute` in order to handle crash recovery correctly.  Otherwise LGTM

https://github.com/llvm/llvm-project/pull/174653