as doesn't recognize "# line file"

[Nick Clifton]

Hi Jun,

> > >  echo \
> > >  '# 1 file.S
> > >  movw %al, %al' > file.s
> > >  gcc file.s
> > >  file.s: Assembler messages:
> > >  file.s:2: Error: `%al' not allowed with `movw'
> > > 
> > > Is this how it's supposed to behave?
> > 
> > Yes.  Try removing the '# 1 file.S' line and just assembling the movw
> > line.  You will still get the same error message.
> 
> Seems like I'm misunderstood here...(sorry if the point wasn't clear)
> What I meant was that I *am* getting the (exact) same error message with
> and without '# 1 file.S', and that's the problem.  I was expecting as to
> report a file name with an uppercase S instead of a lowercase (the error
> itself is intentional):
> 
>  file.S:2: Error: `%al' not allowed with `movw'
> 
> The manual says that as processes the `# line file' output from cpp, and
> on subsequent output, reports file & line specified with it. (The first
> line in e.g.2 was meant to emulate a part of cpp's output)
> So, again, is this how as is supposed to behave, to ignore '# line file'?

OK, now I understand.  There are two bugs here, one in your test case
(and possibly the output of your C pre-processor) and one in the
assembler itself.  The bug in the assembler was that the '#' character
was not set up to indicate the start of a line comment.  Only a '#' as
a line comment character can trigger the assembler's code to interpret
#-line directives.  The patch below fixes this for the i386 port
(which I assume is what you are using).

The second bug is that the #-line directive is only interpreted by the
assembler if the file name is enclosed in double quotes.  So if you
apply the patch below and change your test case to:

        echo \
        '# 1 "file.S"
        movw %al, %al' > file.s

then everything should work.

Cheers
        Nick

PS.  The assembler documentation does say that this feature is
deprecated, so do not rely upon it being present in future releases.


2003-01-29  Nick Clifton  <nickc@redhat.com>

	* config/tc-i386.c (line_comment_chars): Add '#'.  This makes the
	assembler's handling of # <linenum> "<filename>" directives work.

Index: gas/config/tc-i386.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-i386.c,v
retrieving revision 1.137
diff -c -3 -p -w -r1.137 tc-i386.c
*** gas/config/tc-i386.c	23 Jan 2003 12:51:04 -0000	1.137
--- gas/config/tc-i386.c	29 Jan 2003 09:54:15 -0000
*************** const char comment_chars[] = "#/";
*** 207,213 ****
     #NO_APP at the beginning of its output.
     Also note that comments started like this one will always work if
     '/' isn't otherwise defined.  */
! const char line_comment_chars[] = "";
  
  #else
  /* Putting '/' here makes it impossible to use the divide operator.
--- 207,213 ----
     #NO_APP at the beginning of its output.
     Also note that comments started like this one will always work if
     '/' isn't otherwise defined.  */
! const char line_comment_chars[] = "#";
  
  #else
  /* Putting '/' here makes it impossible to use the divide operator.
*************** const char line_comment_chars[] = "";
*** 215,221 ****
  const char comment_chars[] = "#";
  #define PREFIX_SEPARATOR '/'
  
! const char line_comment_chars[] = "/";
  #endif
  
  const char line_separator_chars[] = ";";
--- 215,221 ----
  const char comment_chars[] = "#";
  #define PREFIX_SEPARATOR '/'
  
! const char line_comment_chars[] = "/#";
  #endif
  
  const char line_separator_chars[] = ";";