Implement specializations for immutable ruby objects for ObjectSpace methods

Author: bjfish

CHANGELOG.md

@@ -21,6 +21,7 @@ Compatibility:
 * Disable most `nokogiri` C extension patches when system libraries are not being used (#2693, @aardvark179).
 * Implement `rb_gc_mark_maybe` and `rb_global_variable` to ensure `VALUE` stay live in C extensions (@aardvark179).
 * Implement `rb_imemo_tmpbuf` allocation for `ripper` (@aardvark179).
+* Implement specializations for immutable ruby objects for ObjectSpace methods (@bjfish).
 
 Performance:
 

spec/ruby/library/objectspace/trace_object_allocations_spec.rb

@@ -128,4 +128,22 @@
       ObjectSpace.trace_object_allocations_stop
     end
   end
+
+  it "returns nil for class_path, generation, method_id, sourcefile, and sourceline for immutable objects" do
+    ObjectSpace.trace_object_allocations_start
+    begin
+      one = nil
+      two = 42
+      three = :foo
+      [one, two, three].each do |i|
+        ObjectSpace.allocation_class_path(i).should == nil
+        ObjectSpace.allocation_generation(i).should == nil
+        ObjectSpace.allocation_method_id(i).should == nil
+        ObjectSpace.allocation_sourcefile(i).should == nil
+        ObjectSpace.allocation_sourceline(i).should == nil
+      end
+    ensure
+      ObjectSpace.trace_object_allocations_stop
+    end
+  end
 end

spec/tags/library/objectspace/trace_object_allocations_tags.txt

@@ -11,3 +11,4 @@ slow:ObjectSpace.trace_object_allocations can be nested with more _stop than _st
 slow:ObjectSpace.trace_object_allocations records info for allocation_class_path
 slow:ObjectSpace.trace_object_allocations records info for allocation_method_id
 slow:ObjectSpace.trace_object_allocations can be used without a block using trace_object_allocations_start and _stop
+slow:ObjectSpace.trace_object_allocations returns nil for class_path, generation, method_id, sourcefile, and sourceline for immutable objects

src/main/java/org/truffleruby/stdlib/ObjSpaceNodes.java

@@ -158,6 +158,11 @@ protected Object allocationInfo(RubyDynamicObject object,
                 }
             }
         }
+
+        @Fallback
+        protected Object allocationInfoImmutable(Object object) {
+            return nil;
+        }
     }
 
     @Primitive(name = "allocation_generation")
@@ -172,6 +177,11 @@ protected Object allocationInfo(RubyDynamicObject object) {
                 return trace.gcGeneration;
             }
         }
+
+        @Fallback
+        protected Object allocationGenerationImmutable(Object object) {
+            return nil;
+        }
     }
 
     @Primitive(name = "allocation_method_id")
@@ -193,6 +203,11 @@ protected Object allocationInfo(RubyDynamicObject object) {
                 }
             }
         }
+
+        @Fallback
+        protected Object allocationMethodIdImmutable(Object object) {
+            return nil;
+        }
     }
 
     @Primitive(name = "allocation_sourcefile")
@@ -209,6 +224,11 @@ protected Object allocationInfo(RubyDynamicObject object,
                 return makeStringNode.executeMake(sourcePath, Encodings.UTF_8, CodeRange.CR_UNKNOWN);
             }
         }
+
+        @Fallback
+        protected Object allocationSourcefileImmutable(Object object) {
+            return nil;
+        }
     }
 
     @Primitive(name = "allocation_sourceline")
@@ -223,6 +243,11 @@ protected Object allocationInfo(RubyDynamicObject object) {
                 return trace.allocatingSourceSection.getStartLine();
             }
         }
+
+        @Fallback
+        protected Object allocationSourcelineImmutable(Object object) {
+            return nil;
+        }
     }
 
     @TruffleBoundary