[Truffle] -Xtruffle.translator.print_asts= tool.

Author: chrisseaton

core/src/main/java/org/jruby/truffle/translator/MethodTranslator.java

@@ -166,6 +166,11 @@ public MethodDefinitionNode compileFunctionNode(SourceSection sourceSection, Str
         final RubyRootNode rootNode = new RubyRootNode(
                 context, sourceSection, environment.getFrameDescriptor(), environment.getSharedMethodInfo(), body);
 
+        if (PRINT_AST_METHOD_NAMES.contains(methodName)) {
+            System.err.println(methodName);
+            NodeUtil.printCompactTree(System.err, rootNode);
+        }
+
         if (isBlock) {
             final CallTarget callTarget = Truffle.getRuntime().createCallTarget(rootNode);
             final CallTarget callTargetForMethods = withoutBlockDestructureSemantics(callTarget);

core/src/main/java/org/jruby/truffle/translator/Translator.java

@@ -17,8 +17,14 @@
 import org.jruby.truffle.runtime.RubyContext;
 import org.jruby.util.cli.Options;
 
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
 public abstract class Translator extends org.jruby.ast.visitor.AbstractNodeVisitor<RubyNode> {
 
+    public static final Set<String> PRINT_AST_METHOD_NAMES = new HashSet<>(Arrays.asList(Options.TRUFFLE_TRANSLATOR_PRINT_AST.load().split(",")));
+
     protected final RubyNode currentNode;
     protected final RubyContext context;
     protected final Source source;

core/src/main/java/org/jruby/util/cli/Options.java

@@ -152,6 +152,7 @@ public class Options {
     public static final Option<Boolean> TRUFFLE_DISPATCH_METAPROGRAMMING_ALWAYS_INDIRECT = bool(TRUFFLE, "truffle.dispatch.metaprogramming_always_indirect", false, "Always use indirect calls for the metaprogramming methods #__send__ and #send, and for any call site that has to use #method_missing or #const_missing.");
     public static final Option<Boolean> TRUFFLE_DISPATCH_METHODMISSING_ALWAYS_CLONED = bool(TRUFFLE, "truffle.call.method_missing_always_cloned", true, "Always clone #method_missing call targets.");
     public static final Option<Boolean> TRUFFLE_DISPATCH_METHODMISSING_ALWAYS_INLINED = bool(TRUFFLE, "truffle.call.method_missing_always_inlined", true, "Always inline #method_missing call targets.");
+    public static final Option<String> TRUFFLE_TRANSLATOR_PRINT_AST = string(TRUFFLE, "truffle.translator.print_asts", "", "Comma delimited list of method names to print the AST of after translation.");
 
     public static final Option<Boolean> NATIVE_ENABLED = bool(NATIVE, "native.enabled", true, "Enable/disable native code, including POSIX features and C exts.");
     public static final Option<Boolean> NATIVE_VERBOSE = bool(NATIVE, "native.verbose", false, "Enable verbose logging of native extension loading.");