[PATCH] D135389: [Clang] Emit a warning for ambiguous joined '-o' arguments

[Artem Belevich via Phabricator via cfe-commits]

tra added a comment.

LGTM in principle.



================
Comment at: clang/lib/Driver/Driver.cpp:337
+    std::string Nearest;
+    if (getOpts().findNearest("-" + ArgString, Nearest, IncludedFlagsBitmask,
+                              ExcludedFlagsBitmask) == 1)
----------------
This looks for all 1-symbol mismatches. and may trigger on differences other than `--option` vs `-option`.  E.g. if user passes `-oip-link` (which looks like something we may see in real life), we'll try to find the nearest for `--oip-link` and will get a distance-1 match for the existing option `--hip-link`.

We may need to verify that the nearest match that we've found is indeed due to a missing leading `dash`.



================
Comment at: clang/test/Driver/unknown-arg.c:68
+
+// RUN: %clang -### -offload-arch=sm_70 --offload-arch=sm_70 -offload-device-only -output -o foo \
+// RUN:   %s 2>&1 | FileCheck --check-prefix=O-WARN %s
----------------
I'd also add a test verifying that `-o ffload-device-only` does not trigger the warning.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D135389/new/

https://reviews.llvm.org/D135389