Re: [musl] PATCH: Fix cfi awk scripts for gawk 5 warning

[Rich Felker <dalias@libc.org>]

On Wed, Jan 08, 2020 at 03:06:40PM -0500, Rich Felker wrote:
> On Wed, Jan 08, 2020 at 01:48:09PM -0600, Will Dietz wrote:
> > When `awk` is gawk 5.0.1, the cfi awk scripts print a warning
> > due to unnecessarily escaping '@' character (see attached patch).
> > 
> > Warning message example:
> > 
> > awk: ./tools/add-cfi.x86_64.awk:79: warning: regexp escape sequence `\@' is not a known regexp operator
> > 
> > Trivial patch addressing this is attached.
> > 
> > Unsure which awk implementations are relevant,
> > tested with gawk 4.2.1, gawk 5.0.1, and mawk 1.3.4.
> > Also tested with busybox 1.31.1, didn't check config options used (if that matters).
> > 
> > For all, `.cfi_startproc` seems to be inserted appropriately on example used for testing
> > (src/math/x86_64/lrintf.s) and no warnings were printed.
> > 
> > Minor issue, but seems might as well fix if there aren't awk's requiring escaping '@'.
> > 
> > Thanks!
> > 
> > ~Will
> 
> > From 004799af62609eab3261ea9a75794dd7281ce02e Mon Sep 17 00:00:00 2001
> > From: Will Dietz <w@wdtz.org>
> > Date: Wed, 8 Jan 2020 13:20:44 -0600
> > Subject: [PATCH] tools/add-cfi.{i386,x86_64}.awk: fix for gawk 5, '\@' -> '@'
> > 
> > ---
> >  tools/add-cfi.i386.awk   | 2 +-
> >  tools/add-cfi.x86_64.awk | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/add-cfi.i386.awk b/tools/add-cfi.i386.awk
> > index 9162e309..d05037de 100644
> > --- a/tools/add-cfi.i386.awk
> > +++ b/tools/add-cfi.i386.awk
> > @@ -81,7 +81,7 @@ function adjust_sp_offset(delta) {
> >      in_function = 0
> >    }
> >  }
> > -/^\.type [a-zA-Z0-9_]+,\@function/ {
> > +/^\.type [a-zA-Z0-9_]+,@function/ {
> >    functions[substr($2, 1, length($2)-10)] = 1
> >  }
> >  # not interested in assembler directives beyond this, just pass them through
> > diff --git a/tools/add-cfi.x86_64.awk b/tools/add-cfi.x86_64.awk
> > index bbc90daa..7e1513d6 100644
> > --- a/tools/add-cfi.x86_64.awk
> > +++ b/tools/add-cfi.x86_64.awk
> > @@ -76,7 +76,7 @@ function adjust_sp_offset(delta) {
> >      in_function = 0
> >    }
> >  }
> > -/^\.type [a-zA-Z0-9_]+,\@function/ {
> > +/^\.type [a-zA-Z0-9_]+,@function/ {
> >    functions[substr($2, 1, length($2)-10)] = 1
> >  }
> >  # not interested in assembler directives beyond this, just pass them through
> > -- 
> > 2.25.0-rc1
> > 
> 
> I think this should be okay, but I'll probably wait until after
> release to commit just in case.
> 
> At some point it may make sense to remove these entirely, if we can
> get rid of most of the external asm files.

Others have reported hitting this, and I think it looks fine. I'm
testing with Busybox awk and as long as it works (I expect it to) I'll
include it in this release.

Rich