[LLVMdev] Apple's GCC and .s/.S files in llvm-test (fwd)
daveed at vandevoorde.com
Tue Mar 25 11:04:19 PDT 2008
On Mar 25, 2008, at 1:08 PM, Dale Johannesen wrote:
> On Mar 24, 2008, at 3:18 PM, David Vandevoorde wrote:
>> On Mar 24, 2008, at 5:40 PM, Dale Johannesen wrote:
>>> I don't see a good way to do
>>> full-line comments that works both if you run the preprocessor and
>>> you don't.
>> Could you use "##" instead of "#"?
> Pragmatically, that works (as I'm sure you know). Digging into the
> legalities of C99 I'm not sure that it's guaranteed to work, though.
> Unknown directives actually match the "non-directive" case in the
> grammar in 6.10; while nothing is said anywhere about semantics that I
> can find, I'm not sure why gcc feels this should be a hard error at
"##" is a punctuator (6.4.6) and therefore a preprocessing token of
its own (6.4/1).
A line that starts with "##" is therefore a text-line in 6.10/1
parlance (i.e., it doesn't match the "# non-directive" rule), and so
yes, I think it's guaranteed to work on the preprocessor side of
things. (I know next to nothing about the assembler side of things.)
I don't know either why GCC faults non-directive "# ..." cases. Maybe
it's a C89 leftover, or maybe it has to do with the older "# <line-
More information about the llvm-dev