RFR: 8251850: Simplify ResourceMark constructors using delegation

[John Rose]

On Aug 18, 2020, at 12:49 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
> Poorly named and poorly commented variable from before the beginning of the mercurial age,
> so hard to track down the changeset that introduced it to see if that shed some light.  Good
> thing we have some institutional memory :)

You rang?  The SCCS record looks like this:

1.3 97/08/11 11:39:04 steffen 4 3
+…
+// ResourceArea //////////////////
+
+#ifdef ASSERT
+int ResourceArea::_warned = 0;
+#endif
+
+ResourceArea::ResourceArea() {
+…

That delta (1.3/#4) replaced this code (along with lots of related
code, in a large refactoring of ResourceArea).  It is the first
occurrence of the name “warned”:

-  char* allocate_bytes(int size) {
-    assert(size    >= 0, "negative size in allocate_bytes");
-#ifdef ASSERT
-    // NB: don't make it a fatal error -- otherwise, if you call certain functions
-    // from the debugger, it might report a leak since there might not be a
-    // ResourceMark.
-    // However, in all other situations, calling allocate_bytes with nesting == 0
-    // is a definitive memory leak.  -Urs 10/95
-    static int warned = 0;	// to suppress multiple warnings (e.g. when allocating from the debugger)
-    if (nesting < 1 && !warned++) error("memory leak: allocating w/o ResourceMark!");
-#endif

Several months later we find today’s line:

1.41 99/01/28 14:01:01 renes 53 52
+debug_only(int ResourceArea::_warned;)      // to suppress multiple warnings

Yes, those little lines are all the repo metadata present (in per-file SCCS records).
There are no checkin comments.  Those were the days…

— John