RFR: 8219860: Cleanup ClassFileParser::parse_linenumber_table

[Robbin Ehn]

Hi Claes.

Removes 4 times more than it adds, great!
It seems very reasonably.

Very minor nit, I would remove TRAPS from get_u1(TRAPS) if it's not needed, and 
I can't see that it is. Keep it if you think it makes some sense.

Thanks, Robbin

On 2019-03-08 10:18, Claes Redestad wrote:
> Hi,
> 
> ClassFileParser::parse_linenumber_table use
> CompressedLineNumberWriteStream to turn line number information into a
> compact table for inclusion in each Method. Calls in that area are
> poorly inlined and shows up in startup profiles.
> 
> Additionally, there are a few hacks in the area to disable compiler
> optimizations on Windows due a bug in MSC 2005 that caused stack
> overflow at build time. Testing show no sign of issues, so I suggest
> removing these explicit deoptimizations.
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8219860/open.00/
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8219860
> 
> Testing: tier1-3, verified a 10-15% reduction of instructions in
> parse_linenumber_table.
> 
> Thanks!
> 
> /Claes