Hi Goetz, Looking at the test cases I didn't see any tests for the single argument java.util.Objects.requireNonNull. Using this prototype is that method treated like a hidden frame?
Cheers, Jason ________________________________________ From: core-libs-dev <core-libs-dev-boun...@openjdk.java.net> on behalf of Lindenmaier, Goetz <goetz.lindenma...@sap.com> Sent: Friday, April 12, 2019 5:33 AM To: Mandy Chung; Roger Riggs Cc: Java Core Libs; hotspot-runtime-...@openjdk.java.net Subject: RE: RFR(L): 8218628: Add detailed message to NullPointerException describing what is null. Hi, while waiting for progress on corresponding the JEP, I improved the implementation of generating the NPE message. It now uses a single outputStream. This removes several allocations of temporary data. I also removed TrackingStackSource. The analysis code originally addressed several use cases, for NullPointerExceptions this is not needed. I cleaned up bytecodeUtils from some code not (really) needed. I split get_null_pointer_slot() into two methods: get_NPE_null_slot() and print_NPE_failed_action(). This simplifies the implementation, and streamlines it more with the text in the JEP. I print methods using the code added in "8221470: Print methods in exception messages in java-like Syntax.", so it now prints 'void m(int)' instead of 'm(I)V'. I implemented a row of new test cases, and rearranged the test to test the message part of print_NPE_failed_action() and print_NPE_cause() separated. I made sure all bytecodes handled in these methods are covered. Further I arranged the tests in methods according to the functional properties as discussed in the JEP. http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/07 Best regards, Goetz. > -----Original Message----- > From: Lindenmaier, Goetz > Sent: Donnerstag, 14. März 2019 21:56 > To: 'Mandy Chung' <mandy.ch...@oracle.com>; 'Roger Riggs' > <roger.ri...@oracle.com> > Cc: 'Java Core Libs' <core-libs-dev@openjdk.java.net>; 'hotspot-runtime- > d...@openjdk.java.net' <hotspot-runtime-...@openjdk.java.net> > Subject: RE: RFR(L): 8218628: Add detailed message to NullPointerException > describing what is null. > > Hi, > > I had promised to work on a better wording of the messages. > > This I deliver with this webrev: > http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/05- > otherMessages/ > > The test in the webrev is modified to just print messages along with the > code that raised the messages. > > Please have a look at these files with test output contained in the webrev: > Messages with debug information: > http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/05- > otherMessages/output_with_debug_info.txt > Messages without debug information: > http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/05- > otherMessages/output_no_debug_info.txt > > Especially look at the first few messages, they point out the usefulness > of this change. They precisely say what was null in a chain of dereferences. > > Best regards, > Goetz. > > > > -----Original Message----- > > From: Lindenmaier, Goetz > > Sent: Wednesday, February 13, 2019 10:09 AM > > To: 'Mandy Chung' <mandy.ch...@oracle.com>; Roger Riggs > > <roger.ri...@oracle.com> > > Cc: Java Core Libs <core-libs-dev@openjdk.java.net>; hotspot-runtime- > > d...@openjdk.java.net > > Subject: RE: RFR(L): 8218628: Add detailed message to NullPointerException > > describing what is null. > > > > Hi Mandy, > > > > Thanks for supporting my intend of adding the message as such! > > I'll start implementing this in Java and come back with a webrev > > in a while. > > > > In parallel, I would like to continue discussing the other > > topics, e.g., the wording of the message. I will probably come up > > with a separate webrev for that. > > > > Best regards, > > Goetz. > > > > > > > > > -----Original Message----- > > > From: core-libs-dev <core-libs-dev-boun...@openjdk.java.net> On Behalf > > > Of Mandy Chung > > > Sent: Tuesday, February 12, 2019 7:32 PM > > > To: Roger Riggs <roger.ri...@oracle.com> > > > Cc: Java Core Libs <core-libs-dev@openjdk.java.net>; hotspot-runtime- > > > d...@openjdk.java.net > > > Subject: Re: RFR(L): 8218628: Add detailed message to > > NullPointerException > > > describing what is null. > > > > > > On 2/8/19 11:46 AM, Roger Riggs wrote: > > > > Hi, > > > > > > > > A few higher level issues should be considered, though the details > > > > of the webrev captured my immediate attention. > > > > > > > > Is this the right feature and is this the right level of implementation > > > > (C++/native)? > > > > : > > > > How much of this can be done in Java code with StackWalker and other > > > > java APIs? > > > > It would be a shame to add this much native code if there was a more > > > robust > > > > way to implement it using APIs with more leverage. > > > > > > Improving the NPE message for better diagnosability is helpful while > > > I share the same concern Roger raised. > > > > > > Implementing this feature in Java and the library would be a better > > > choice as this isn't absolutely required to be done in VM in native. > > > > > > NPE keeps a backtrace capturing the method id and bci of each stack > > > frame. One option to explore is to have StackWalker to accept a > > > Throwable object that returns a stream of StackFrame which allows > > > you to get the method and BCI and also code source (I started a > > > prototype for JDK-8189752 some time ago). It can use the bytecode > > > library e.g. ASM to read the bytecode. For NPE message, you can > > > implement a specialized StackFrameTraverser just for building > > > an exception message purpose. > > > > > > Mandy
