On Sun, 17 Jan 2021 03:57:59 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
> See the bug for most details. A few notes here about some implementation > details: > > In the `PointerLocation` class, I added more consistency w.r.t. whether or > not a newline is printed. It used to for some address types, but not others. > Now it always does. And if you see a comment something like the following: > > ` getTLAB().printOn(tty); // includes "\n" ` > > That's just clarifying whether or not the `printOn()` method called will > include the newline. Some do and some don't, and knowing what the various > `printOn()` methods do makes getting the proper inclusion of the newline > easier to understand. > > I added `verbose` and `printAddress` boolean arguments to > `PointerLocation.printOn()`. Currently they are always `true`. The false > arguments will be used when I complete > [JDK-8250801](https://bugs.openjdk.java.net/browse/JDK-8250801), which will > use `PointerFinder/Location` to show what each register points to. > > The CR mentions that the main motivation for this work is for eventual > replacement of the old clhsdb `whatis` command, which was implemented in > javascript. It used to resolve DSO symbols, whereas `findpc` did not. The > `whatis` code did this with the following: > > var dso = loadObjectContainingPC(addr); > if (dso == null) { > return ptrLoc.toString(); > } > var sym = dso.closestSymbolToPC(addr); > if (sym != null) { > return sym.name + '+' + sym.offset; > } > And now you'll see something similar in the PointerFinder code: > > loc.loadObject = cdbg.loadObjectContainingPC(a); > if (loc.loadObject != null) { > loc.nativeSymbol = loc.loadObject.closestSymbolToPC(a); > return loc; > } > Note that now that `findpc` does everything that `whatis` used to (and more), > we don't really need to add a java version of `whatis`, but I'll probably do > so anyway just help out people who are used to using the `whatis` command. > That will be done using > [JDK-8244670](https://bugs.openjdk.java.net/browse/JDK-8244670) Looks good, thanks. (Comment in PointerLocation.java, treat as you see fit.) src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/PointerLocation.java line 247: > 245: stackThread.getStackBase(), > stackThread.lastSPDbg(), > 246: > stackThread.getStackBase().addOffsetTo(-stackThread.getStackSize()), > 247: stackThread); When we print a JavaThread, in the verbose block, the final argument to tty.format in line 247, I wonder what that prints? We then call printThreadInfoOn() which will first print the quoted thread name, so maybe we don't need that item. Or maybe we want the JavaThread.toString()? ------------- Marked as reviewed by kevinw (Committer). PR: https://git.openjdk.java.net/jdk/pull/2111
