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

[David Faust <david.faust@oracle.com>]

On 7/25/23 15:58, Jose E. Marchesi wrote:
> 
>> 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...

Yeah, it causes build failures if totally removed and failures
in gas/macros/macros.exp if left blank.  Best to leave it.

Here's a v2 with just the redundant sentence in the manual removed.


This little patch makes the BPF assembler accept '#' as an inline
comment character, which clang -S seems to use.

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  | 5 ++---
 2 files changed, 3 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..3fde0e6b613 100644
--- a/gas/doc/c-bpf.texi
+++ b/gas/doc/c-bpf.texi
@@ -64,9 +64,8 @@ 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.
 
 @cindex statement separator, BPF
 Statements and assembly directives are separated by newlines.
-- 
2.40.1