RFR: 8352422: [ubsan] Out-of-range reported in ciMethod.cpp:917:20: runtime error: 2.68435e+09 is outside the range of representable values of type 'int'

[Marc Chevalier]

The double `(double)count * prof_factor * method_life / counter_life + 0.5`
can overflow a 32-bit int, causing UB on casting, but in practice computing
a wrong scale, probably.

We just need to compare that the cast is not going to overflow. This is possible
because `INT_MAX` is exactly representable in a `double`. It is also good to
notice that the expression `(double)count * prof_factor * method_life / counter_life + 0.5`
cannot overflow a `double`:
- `count` is a int, max value = 2^31-1 < 2.2e9
- `method_lie` is a int, max value < 2.2e9
- `prof_factor` is a float, max value < 3.5e38
- `counter_life` is a int, positive at this point, so min value = 1
So, the whole expression is bounded by 16.94e56 + 0.5, which is much smaller than the
max value of a double (about 1.8e308). We probably would have precision issues, but
it probably doesn't matter a lot.

The semantic I picked here is basically `min(INT_MAX, count_d)`, so it'd always fit.

Thanks,
Marc

-------------

Commit messages:
 - Check for overflow

Changes: https://git.openjdk.org/jdk/pull/24824/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24824&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352422
  Stats: 7 lines in 1 file changed: 5 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/24824.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24824/head:pull/24824

PR: https://git.openjdk.org/jdk/pull/24824