RFR: 8283641: Large value for CompileThresholdScaling causes assert [v2]

[Ioi Lam]

> Please review this trivial fix that checks for overflow of `(intx)(threshold * scale)`
> 
> Before:
> 
> $ java -XX:CompileThresholdScaling=12345678901234567890.0 -version
> ...
> # Internal Error (/jdk/open/src/hotspot/share/utilities/powerOfTwo.hpp:54), pid=4147940, tid=4147941
> # assert(value > T(0)) failed: value must be > 0
> 
> 
> After:
> 
> 
> $ java -XX:CompileThresholdScaling=12345678901234567890.0 -version
> intx Tier0InvokeNotifyFreqLog=32 is outside the allowed range [ 0 ... 30 ]
> ...
> OnStackReplacePercentage cannot be validated because CompileThreshold value is invalid
> CompileThreshold (9223372036854775807) must be between 0 and 1073741823
> Error: Could not create the Java Virtual Machine.
> Error: A fatal exception has occurred. Program will exit.
> 
> 
> Tested with tiers 1-2.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  @vnkozlov comment: no need to check for min_intx

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7944/files
  - new: https://git.openjdk.java.net/jdk/pull/7944/files/b8aab7ac..f84f63be

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7944&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7944&range=00-01

  Stats: 4 lines in 1 file changed: 2 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7944.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7944/head:pull/7944

PR: https://git.openjdk.java.net/jdk/pull/7944