add simple object events to tracepoint api (c-api only)

ext/-test-/tracepoint/extconf.rb

@@ -0,0 +1 @@
+create_makefile("-test-/tracepoint")

ext/-test-/tracepoint/obj.c

@@ -0,0 +1,37 @@
+#include "ruby.h"
+#include "ruby/debug.h"
+
+static size_t count;
+static VALUE objects[10];
+
+void
+newobj_callback(VALUE tpval, void *data)
+{
+    rb_trace_arg_t *tparg = rb_tracearg_from_tracepoint(tpval);
+    VALUE obj = rb_tracearg_object(tparg);
+
+    if (count < sizeof(objects))
+        objects[count++] = obj;
+}
+
+VALUE
+tracepoint_track_newobj(VALUE self)
+{
+    VALUE tpval = rb_tracepoint_new(0, RUBY_EVENT_OBJ_NEW, newobj_callback, 0);
+
+    count = 0;
+    memset(objects, (VALUE)Qnil, sizeof(objects));
+
+    rb_tracepoint_enable(tpval);
+    rb_yield(Qundef);
+    rb_tracepoint_disable(tpval);
+
+    return rb_ary_new4(count, objects);
+}
+
+void
+Init_tracepoint(void)
+{
+    VALUE mBug = rb_define_module("Bug");
+    rb_define_module_function(mBug, "tracepoint_track_newobj", tracepoint_track_newobj, 0);
+}

gc.c

@@ -687,9 +687,11 @@ VALUE
 rb_newobj_of(VALUE klass, VALUE flags)
 {
     VALUE obj;
+    rb_thread_t *th = GET_THREAD();
 
     obj = newobj(klass, flags);
     OBJSETUP(obj, klass, flags);
+    EXEC_EVENT_HOOK(th, RUBY_EVENT_OBJ_NEW, th->self, 0, 0, obj);
 
     return obj;
 }
@@ -907,6 +909,7 @@ make_io_deferred(RVALUE *p)
 static int
 obj_free(rb_objspace_t *objspace, VALUE obj)
 {
+    rb_thread_t *th = GET_THREAD();
     switch (BUILTIN_TYPE(obj)) {
       case T_NIL:
       case T_FIXNUM:
@@ -916,6 +919,8 @@ obj_free(rb_objspace_t *objspace, VALUE obj)
 	break;
     }
 
+    EXEC_EVENT_HOOK(th, RUBY_EVENT_OBJ_FREE, th->self, 0, 0, obj);
+
     if (FL_TEST(obj, FL_EXIVAR)) {
 	rb_free_generic_ivar((VALUE)obj);
 	FL_UNSET(obj, FL_EXIVAR);
@@ -2559,8 +2564,10 @@ static int
 gc_mark_ptr(rb_objspace_t *objspace, VALUE ptr)
 {
     register uintptr_t *bits = GET_HEAP_BITMAP(ptr);
+    rb_thread_t *th = GET_THREAD();
     if (MARKED_IN_BITMAP(bits, ptr)) return 0;
     MARK_IN_BITMAP(bits, ptr);
+    EXEC_EVENT_HOOK(th, RUBY_EVENT_OBJ_MARK, th->self, 0, 0, ptr);
     objspace->heap.marked_num++;
     return 1;
 }

include/ruby/debug.h

@@ -67,6 +67,7 @@ VALUE rb_tracearg_binding(rb_trace_arg_t *trace_arg);
 VALUE rb_tracearg_self(rb_trace_arg_t *trace_arg);
 VALUE rb_tracearg_return_value(rb_trace_arg_t *trace_arg);
 VALUE rb_tracearg_raised_exception(rb_trace_arg_t *trace_arg);
+VALUE rb_tracearg_object(rb_trace_arg_t *trace_arg);
 
 /* undocumented advanced tracing APIs */
 

include/ruby/ruby.h

@@ -1599,6 +1599,12 @@ int ruby_native_thread_p(void);
 #define RUBY_EVENT_SWITCH         0x20000
 #define RUBY_EVENT_COVERAGE       0x40000
 
+/* GC events (c-api only) */
+#define RUBY_EVENT_OBJ_NEW  0x100000
+#define RUBY_EVENT_OBJ_MARK 0x200000
+#define RUBY_EVENT_OBJ_FREE 0x400000
+#define RUBY_EVENT_OBJ_ALL  0xF00000
+
 typedef unsigned long rb_event_flag_t;
 typedef void (*rb_event_hook_func_t)(rb_event_flag_t evflag, VALUE data, VALUE self, ID mid, VALUE klass);
 

test/-ext-/tracepoint/test_obj.rb

@@ -0,0 +1,24 @@
+require 'test/unit'
+require '-test-/tracepoint'
+
+class TestTracepointObj < Test::Unit::TestCase
+  def test_not_available_from_ruby
+    assert_raises ArgumentError do
+      TracePoint.trace(:obj_new){}
+    end
+  end
+
+  def test_tracks_newly_created_objects
+    newobjs = Bug.tracepoint_track_newobj{
+      99
+      'abc'
+      v="foobar"
+      Object.new
+      nil
+    }
+
+    assert_equal 2, newobjs.size
+    assert_equal 'foobar', newobjs[0]
+    assert_equal Object, newobjs[1].class
+  end
+end

vm_trace.c

@@ -556,6 +556,9 @@ get_event_id(rb_event_flag_t event)
 	C(thread_begin, THREAD_BEGIN);
 	C(thread_end, THREAD_END);
 	C(specified_line, SPECIFIED_LINE);
+	C(obj_new, OBJ_NEW);
+	C(obj_mark, OBJ_MARK);
+	C(obj_free, OBJ_FREE);
       case RUBY_EVENT_LINE | RUBY_EVENT_SPECIFIED_LINE: CONST_ID(id, "line"); return id;
 #undef C
       default:
@@ -813,6 +816,21 @@ rb_tracearg_raised_exception(rb_trace_arg_t *trace_arg)
     return trace_arg->data;
 }
 
+VALUE
+rb_tracearg_object(rb_trace_arg_t *trace_arg)
+{
+    if (trace_arg->event & (RUBY_EVENT_OBJ_ALL)) {
+	/* ok */
+    }
+    else {
+	rb_raise(rb_eRuntimeError, "not supported by this event");
+    }
+    if (trace_arg->data == Qundef) {
+	rb_bug("tp_attr_raised_exception_m: unreachable");
+    }
+    return trace_arg->data;
+}
+
 /*
  * Type of event
  *