RFR(L): JEP165: Compiler Control

Nils Eliasson nils.eliasson at oracle.com
Wed Oct 7 10:38:05 UTC 2015

Hi all,

Latest webrev including fixes after comments from Chris and Zoltan:


On 2015-09-22 19:21, Nils Eliasson wrote:
> Hi,  > > This is the initial RFR for JEP165: Compiler Control. This feature 
 > enables runtime manageable, method dependent compiler flags. > 
(Immutable for the duration of a compilation.) > > The change includes: 
- A parser for the directives format (json like) > including vmtests 
(json.cpp/hpp) - A component for construction of > compiler directives 
(directivesParser.cpp/hpp) - The directives > including the option 
definitions, default values and compilecommand > relations 
(compilerDirectives.cpp/hpp) - Diagnostic commands for > working with 
the directives - installing, removing, printing - Lots > of small 
changes wherever we access flags or legacy compilecommands > in the 
compiler > > Notes: The feature is documented in the JEP > 
(https://bugs.openjdk.java.net/browse/JDK-8046155). > > Currently only a 
small amount of compiler flags are included in the > change. The flags 
are a representative selection of different types > targeting both 
compilers. All of them existed as CompilerOracle > option commands. Two 
commands was not included in the directives due > to time constraints - 
CompilerThresholdScaling and UseRTMLocks. Both > are accessed from 
runtime (outside any compiler) and requires some > special handling. 
(Solved but not implemented.) > > Full backwards compatibility with 
CompileCommands is implemented but > can be turned off with flag 
-XX:CompileCommandCompatibilty. Also meta > handling the compatibility 
flag by supporting it in the directives > (test feature). > > The change 
contain some rough edges that will polished over the > coming days. > > 
JEP: https://bugs.openjdk.java.net/browse/JDK-8046155 Hotspot webrev: > 
http://cr.openjdk.java.net/~neliasso/8046155/webrev.01/ JDK webrev: > 
http://cr.openjdk.java.net/~neliasso/8046155/webrev_jdk.01/ > > Please 
review! > > Best regards, Nils Eliasson

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20151007/118eb64b/attachment.html>

More information about the hotspot-compiler-dev mailing list