[PATCH] D105695: [clang][tooling] Accept Clang invocations with "-fno-integrated-as"

[Duncan P. N. Exon Smith via Phabricator via cfe-commits]

dexonsmith added inline comments.


================
Comment at: clang/lib/Tooling/Tooling.cpp:119-122
+      if (isa<driver::AssembleJobAction>(A)) {
+        ExternalAssembler = true;
+        break;
+      }
----------------
Seems like this could (unexpectedly?) let through a command with multiple `-cc1`s (if I'm reading the code right). Consider these two cases:
```
lang=zsh
% clang -x c a.c b.c -c -fno-integrated-as -###
% clang -arch x86_64 -arch arm64 -x c /dev/null -c -fno-integrated-as -###
```
The first compiles two separate files; the second compiles a file with two separate architectures. But IIUC, the logic below doesn't expect this and will now let them through (ultimately, there's no reason scan-deps couldn't be updated to handle this! but that's not in scope for this patch, and maybe doesn't apply generally to clang-tooling).

Also, I'm not sure it's good that it was rejected, but I think the previous code would reject the following command-line and the new code will accept it:
```
% clang -x c /dev/null -###
```

I wonder if it'd be simpler to search for a supported action, and reject if zero or multiple are found. Something like:
```
lang=c++
const driver::Command *Cmd = nullptr;
for (const Action *A : Actions) {
  A = lookThrough(A);
  if (!shouldIgnore(*A)) // ignore some actions...
    continue;
  if (shouldReject(*A)) // if needed, error on some actions...
    return error(...);

  if (Cmd) // error if we hit a second candidate
    return error(...);
  Cmd = cast<driver::Command>(*A);
}
if (!Cmd) // error if we found no candidate
  return error(...);
```


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105695/new/

https://reviews.llvm.org/D105695