Re: Who broke options.h?

[David Malcolm <dmalcolm at redhat dot com>]

On Tue, 2017-04-25 at 06:59 -0700, Steve Kargl wrote:
> Someone (other than Richard who seems to have fixed his
> bootstrap issue) in the last 3 days has broken bootstrap
> on FreeBSD.  The generated file gcc/options.h contains
> code of the form
> 
>   OPT_C = 116,                               /* -C */
>   OPT_CC = 117,                              /* -CC */
>   OPT_c = 118,                               /* -c */
>   OPT_C = 119,                               /* -C */
>   OPT_coverage = 120,                        /* -coverage */
>   OPT_cpp_ = 121,                            /* -cpp= */
>   OPT_cpp = 122,                             /* -cpp */
>   OPT_d = 123,                               /* -d */
>   OPT_D = 124,                               /* -D */
>   OPT_d = 125,                               /* -d */
>   OPT_defsym_ = 126,                         /* -defsym= */
>   OPT_defsym = 127,                          /* -defsym */
>   OPT_d = 128,                               /* -d */
>   OPT_D = 129,                               /* -D */
> 
> The sudden dumping ground of everyone's pet project into
> trunk after the new branch has been created is making it 
> impossible to bisect this issue.

Presumably the issue is the duplicate names within an enum.  Above,
OPT_C has values 116, 119
OPT_d has values 123, 125, 128
OPT_D has values 124, 129
etc.

Looking at the code that writes out that enum in opth-gen.awk, I see:

   443  enum_value = 0
   444  for (i = 0; i < n_opts; i++) {
   445          # Combine the flags of identical switches.  Switches
   446          # appear many times if they are handled by many front
   447          # ends, for example.
   448          while( i + 1 != n_opts && opts[i] == opts[i + 1] ) {
   449                  flags[i + 1] = flags[i] " " flags[i + 1];
   450                  i++;
   451          }

Lines 445-451 suggest that the options are meant to be in some kind of
sorted order, so that duplicates will be adjacent.

In the output you posted the duplicates are *not* adjacent.  So is
there some implicit assumption in the awk code about the sorting of
options, that somehow isn't satisfied on the machine you're seeing this
on?

>From what I can tell, the n_opts and opts in that file come direct from
 opt-read.awk, which gets them from opt-gather.awk, which appears to
sort them (but my awk skills are weak).

Alternatively, maybe the collisions are caused by some names needing
opt_sanitized_name?  (you could try making that return its argumen
unmodified to see if it shows anything, I guess)  But I don't see any
new option in trunk in the last 3 days.

Hope this is helpful
Dave