RFR: 8276571: C2: pass compilation options as structure

[Aleksey Shipilev]

On Wed, 3 Nov 2021 18:49:47 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Currently we pass several compilation options as separate arguments to `Compile`: 
> 
> Compile C(env, target, entry_bci, subsume_loads, do_escape_analysis, eliminate_boxing, do_locks_coarsening, install_code, directive); 
> 
> Originally we had only `subsume_loads` option but we added few since then and we may add more. 
> 
> I suggest to add new `Options` class to pass these values into `Compile`.

I like the way it is going, but unfortunately I find the list of unnamed boolean arguments as confusing and error-prone as before... Could we use "named parameters idiom" here, or some other way to name these parameters?

Something like:


class Options {
  Options() : _subsume_loads(false), _do_escape_analysis(false) {};
  Options& subsume_loads() { _subsume_loads = true; return *this; }
  Options& do_escape_analysis() { _do_escape_analysis = true; return *this; }
}

src/hotspot/share/opto/compile.cpp line 490:

> 488: #ifndef PRODUCT
> 489:   // Check if recompiling
> 490:   if ((subsume_loads() == false) && PrintOpto) {

Suggestion:

  if (!subsume_loads() && PrintOpto) {

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

PR: https://git.openjdk.java.net/jdk/pull/6237