[PATCH] D39538: [llvm-ar] Support an options string that start with a dash

[Rafael Avila de Espindola via llvm-commits]

Martin Storsjö <martin at martin.st> writes:

> On Thu, 2 Nov 2017, Rafael Avila de Espindola wrote:
>
>> Martin Storsjö via Phabricator <reviews at reviews.llvm.org> writes:
>>
>>> mstorsjo updated this revision to Diff 121361.
>>> mstorsjo added a comment.
>>>
>>> Break out of the loop on '--' and once an argument with a stripped dash is found.
>>>
>>>
>>> https://reviews.llvm.org/D39538
>>>
>>> Files:
>>>   test/tools/llvm-ar/default-add.test
>>>   tools/llvm-ar/llvm-ar.cpp
>>>
>>>
>>> Index: tools/llvm-ar/llvm-ar.cpp
>>> ===================================================================
>>> --- tools/llvm-ar/llvm-ar.cpp
>>> +++ tools/llvm-ar/llvm-ar.cpp
>>> @@ -127,6 +127,8 @@
>>>    "  [v] - be verbose about actions taken\n"
>>>  );
>>>
>>> +static const char OptionChars[] = "dmpqrtxabiosSTucv";
>>> +
>>>  // This enumeration delineates the kinds of operations on an archive
>>>  // that are permitted.
>>>  enum ArchiveOperation {
>>> @@ -879,6 +881,23 @@
>>>        Stem.find("lib") != StringRef::npos)
>>>      return libDriverMain(makeArrayRef(argv, argc));
>>>
>>> +  for (int i = 1; i < argc; i++) {
>>> +    // If an argument starts with a dash and only contains chars
>>> +    // that belong to the options chars set, remove the dash.
>>> +    // We can't handle it after the command line options parsing
>>> +    // is done, since it will error out on an unrecognized string
>>> +    // starting with a dash.
>>> +    // Make sure this doesn't match the actual llvm-ar specific options
>>> +    // that start with a dash.
>>> +    if (argv[i][0] == '-' &&
>>> +        strspn(&argv[i][1], OptionChars) + 1 == strlen(argv[i])) {
>>> +      argv[i]++;
>>> +      break;
>>> +    }
>>> +    if (!strcmp(argv[i], "--"))
>>> +      break;
>>> +  }
>>
>> The intention is to not support "--format=gnu -rc"?
>
> No, that should work (since this is strcmp, not strncmp).
>
> The intention is to avoid issues with "llvm-ar rc foo.a -- -obj", where 
> "-obj" is an object file name that would otherwise be interpreted as a 
> potential ar command string, starting with a dash.

Ah, could you use StringRef's ==? That should make it clear that it is
not checking a prefix.

LGTM with that.

Cheers,
Rafael