Enhance ability to dump JSC Options.
<https://webkit.org/b/143357>
Reviewed by Benjamin Poulain.
Some enhancements to how the JSC options work:
- Add a JSC_showOptions option which take values: 0 = None, 1 = Overridden only,
2 = All, 3 = Verbose.
The default is 0 (None). This dumps nothing.
With the Overridden setting, at VM initialization time, we will dump all
option values that have been changed from their default.
With the All setting, at VM initialization time, we will dump all option values.
With the Verbose setting, at VM initialization time, we will dump all option
values along with their descriptions (if available).
- We now store a copy of the default option values.
We later use this for comparison to tell if an option has been overridden, and
print the default value for reference. As a result, we no longer need the
didOverride flag since we can compute whether the option is overridden at any time.
- Added description strings to some options to be printed when JSC_showOptions=3 (Verbose).
This will come in handy later when we want to rename some of the options to more sane
names that are easier to remember. For example, we can change
Options::dfgFunctionWhitelistFile() to Options::dfgWhiteList(), and
Options::slowPathAllocsBetweenGCs() to Options::forcedGcRate(). With the availability
of the description, we can afford to use shorter and less descriptive option names,
but they will be easier to remember and use for day to day debugging work.
In this patch, I did not change the names of any of the options yet. I only added
description strings for options that I know about, and where I think the option name
isn't already descriptive enough.
- Also deleted some unused code.
(CommandLine::parseArguments):
(JSC::Options::initialize):
(JSC::Options::setOption):
(JSC::Options::dumpAllOptions):
(JSC::Options::dumpOption):
(JSC::Options::Option::dump):
(JSC::Options::Option::operator==):
(JSC::OptionRange::rangeString):
(JSC::Options::Option::Option):
(JSC::Options::Option::operator!=):
