[Bug gcov-profile/64874] New: gcov's magic number possibly increasing too quickly with new gcc version numbering scheme.

["rearnsha at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64874

            Bug ID: 64874
           Summary: gcov's magic number possibly increasing too quickly
                    with new gcc version numbering scheme.
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rearnsha at gcc dot gnu.org

A comment in gcov-io.h reads:

"   Although the ident and version are formally 32 bit numbers, they
   are derived from 4 character ASCII strings.  The version number
   consists of the single character major version number, a two
   character minor version number (leading zero for versions less than
   10), and a single character indicating the status of the release.
   That will be 'e' experimental, 'p' prerelease and 'r' for release.
   Because, by good fortune, these are in alphabetical order, string
   collating can be used to compare version strings.  Be aware that
   the 'e' designation will (naturally) be unstable and might be
   incompatible with itself.  For gcc 3.4 experimental, it would be
   '304e' (0x33303465).  When the major version reaches 10, the
   letters A-Z will be used.  Assuming minor increments releases every
   6 months, we have to make a major increment every 50 years.
   Assuming major increments releases every 5 years, we're ok for the
   next 155 years -- good enough for me."

With the move to increasing the major version number with every year, we are
going to exhaust this magic number scheme much more rapidly than cited above.

Perhaps we should change how the magic number is generated.