[llvm-dev] [llvm-rc] absolute.test failing (original) (raw)

Martin Storsjö via llvm-dev llvm-dev at lists.llvm.org
Thu Jan 10 00:01:28 PST 2019

On Wed, 9 Jan 2019, David Greene wrote:

I've come across a curious and pernicious problem in llvm-rc. absolute.test checks that llvm-rc can accept a filename that is an absolute path. And it works just fine. Until you run it with a file that starts with "/c."

Hmm, that's rather unfortunate indeed.

FWIW, this test doesn't test specifically whether llvm-rc can accept an absolute filename as command line argument - all the llvm-rc tests run llvm-rc with absolute filenames as arguments. This test checks whether llvm-rc can handle an absolute filename reference within a rc file.

I presume you run into the same issue on all other tests in test/tools/llvm-rc as well?

These will fail:

llvm-rc /crawl/through/some/path/to/my.rc llvm-rc /c/some/path/to/my.rc The option parser ends up interpreting "/" as an option prefix and then the parser matches it to this in tools/llvm-rc/Opts.td: def CODEPAGE : JoinedOrSeparate<[ "/", "-" ], "C">, HelpText<"Set the codepage used for input strings.">; The test then fails with: Exactly one input file should be provided. The same problem happens with files that begin with "/r" (/read/the/path/to/my.rc) "/sl" (/slink/along/the/path/to/my.rc) or any other path that happens to begin with the same text as an option in Opts.td. This triggered on one of our builders that just happens to build to a path that begins with "/c." Presumably none of the existing Buildbots build to paths that cause problems. It's easy enough to construct a test for this, but I'm not sure how/if llvm-rc should be fixed. I don't know why it accepts both "/" and "-" as option prefixes. As this mostly seems related to Windows (resource files), should tests be UNSUPPORTED on every other platform? Or is llvm-rc intended to be a cross-platform way to create resource files?

It's definitely intended as a cross-platform tool for generating windows resource files, to allow for cross compilation etc.

If the latter, then it seems like options ought to use the "/" prefix on Windows and "-" everywhere else so as not to conflict with path specifiers.

Well, build scripts that call llvm-rc might be using either (more or less agnostic of what platform it runs on). I personally prefer always using "-" everywhere though (which also is supported on windows, and also supported by the original microsoft tools, even if their help listings only display the form with a "/").

FWIW, lld-link also implements the same form of options using both prefixes, but there's less risk of unintended matches as most option names are full words, not single-char abbreviations.

One way of disambiguating between option and pathname for the sake of the tests, would be to add '--' before the path arguments, which seems to be handled by the LLVM options parser at least. Does that sound sensible to you (and others CC:d)?

// Martin

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