Re: [PATCH] bpf: accept # as an inline comment char

["Jose E. Marchesi" <jose.marchesi@oracle.com>]

> On 7/25/23 13:56, Jose E. Marchesi wrote:
>> 
>>> This little patch makes the BPF assembler accept '#' as an inline
>>> comment character, which clang -S seems to use.
>>>
>>> Tested on bpf-unknown-none.
>>> OK?
>>>
>>> gas/
>>> 	* config/tc-bpf.c (comment_chars): Add '#'.
>>> 	* doc/c-bpf.texi (BPF Special Characters): Add note that '#' may
>>> 	be used for inline comments.
>>> ---
>>>  gas/config/tc-bpf.c | 2 +-
>>>  gas/doc/c-bpf.texi  | 7 ++++---
>>>  2 files changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/gas/config/tc-bpf.c b/gas/config/tc-bpf.c
>>> index c56b8fe984f..56c434c223d 100644
>>> --- a/gas/config/tc-bpf.c
>>> +++ b/gas/config/tc-bpf.c
>>> @@ -53,7 +53,7 @@ struct bpf_insn
>>>    unsigned int has_imm64 : 1;
>>>  };
>>>  
>>> -const char comment_chars[]        = ";";
>>> +const char comment_chars[]        = ";#";
>>>  const char line_comment_chars[]   = "#";
>>>  const char line_separator_chars[] = "`";
>>>  const char EXP_CHARS[]            = "eE";
>>> diff --git a/gas/doc/c-bpf.texi b/gas/doc/c-bpf.texi
>>> index 8f39ab314a7..597b3b30b30 100644
>>> --- a/gas/doc/c-bpf.texi
>>> +++ b/gas/doc/c-bpf.texi
>>> @@ -64,9 +64,10 @@ the host endianness is used.
>>>  
>>>  @cindex line comment character, BPF
>>>  @cindex BPF line comment character
>>> -The presence of a @samp{;} on a line indicates the start of a comment
>>> -that extends to the end of the current line.  If a @samp{#} appears as
>>> -the first character of a line, the whole line is treated as a comment.
>>> +The presence of a @samp{;} or a @samp{#} on a line indicates the start
>>> +of a comment that extends to the end of the current line.  If a
>>> +@samp{#} appears as the first character of a line, the whole line is
>>> +treated as a comment.
>> 
>> Hm, isnt' this second sentence a quite obvious corollary now? :)
>
> Well, yes I suppose so.. :)
>
> I left it in because I did not touch (nor look further at):
>
>   const char line_comment_chars[]   = "#";
>
> which was what the sentence documented.
> I agree it doesn't add much anymore though, shall I remove it?

Hm, not sure.  Try if it makes a difference in practice...

>> 
>>>  @cindex statement separator, BPF
>>>  Statements and assembly directives are separated by newlines.