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Scheduler for controlling the Execution of IR Passes #917

merged 4 commits into from

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After a discussion with @enebo and @subbuss, I propose a new simple interface for controlling the execution of IR passes. Explanation:

  • it is just an Iterable<CompilerPass>, as every configuration of IR passes is a directed acyclic graph (starting on IR and ending up in (optimized) IR)
  • If a IR pass requires to run after another pass (dependency), this must be modeled as an edge
  • There cannot be cycles, since this means to have unresolvable dependencies on passes
  • Hence, there must be a topological sort for each allowed execution configuration of IR passes
  • This is modeled as Iterable interface in CompilerPassScheduler

In future, there are maybe more features required to linearize and resolve the dependencies on IR passes. However, this simple interface should then be extended by more sophisticated features and then iterate in the end on the Scheduler.

@enebo enebo merged commit e135970 into jruby:master

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18 core/src/main/java/org/jruby/ir/
@@ -2,6 +2,7 @@
import java.util.ArrayList;
import java.util.HashSet;
+import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.jruby.RubyInstanceConfig;
@@ -10,6 +11,7 @@
@@ -62,6 +64,22 @@ public IRModuleBody getObject() {
return object;
+ public CompilerPassScheduler schedulePasses() {
+ CompilerPassScheduler scheduler = new CompilerPassScheduler() {
+ private Iterator<CompilerPass> iterator;
+ {
+ this.iterator = compilerPasses.iterator();
+ }
+ @Override
+ public Iterator<CompilerPass> iterator() {
+ return this.iterator;
+ }
+ };
+ return scheduler;
+ }
public List<CompilerPass> getCompilerPasses(IRScope scope) {
return compilerPasses;
5 core/src/main/java/org/jruby/ir/
@@ -36,6 +36,7 @@
@@ -653,7 +654,6 @@ private void runCompilerPasses() {
// SSS FIXME: Why is this again? Document this weirdness!
// Forcibly clear out the shared eval-scope variable allocator each time this method executes
// SSS FIXME: We should configure different optimization levels
// and run different kinds of analysis depending on time budget. Accordingly, we need to set
// IR levels/states (basic, optimized, etc.) and the
@@ -661,7 +661,8 @@ private void runCompilerPasses() {
// while another thread is using it. This may need to happen on a clone()
// and we may need to update the method to return the new method. Also,
// if this scope is held in multiple locations how do we update all references?
- for (CompilerPass pass: getManager().getCompilerPasses(this)) {
+ CompilerPassScheduler scheduler = getManager().schedulePasses();
+ for (CompilerPass pass: scheduler) {;
4 core/src/main/java/org/jruby/ir/passes/
@@ -0,0 +1,4 @@
+public interface CompilerPassScheduler extends Iterable<CompilerPass> {
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