RFR (L) JDK-8230199: consolidate signature parsing code in HotSpot sources

[Lois Foltan]

On 1/28/2020 5:03 PM, coleen.phillimore at oracle.com wrote:
>
>
> On 1/28/20 3:50 PM, Lois Foltan wrote:
>> On 1/27/2020 4:36 PM, coleen.phillimore at oracle.com wrote:
>>>
>>> Lois,  So many nice cleanups in this patch!
>>
>> Thanks for your review Coleen!  Responses interspersed below. New 
>> webrev is at: 
>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.2/webrev/index.html
>>
>>>
>>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/src/hotspot/cpu/sparc/sharedRuntime_sparc.cpp.frames.html 
>>>
>>>
>>> 1910 ss.skip_array_prefix(1); // skip one '['
>>> 1911 if (ss.is_primitive())
>>> 1912 in_elem_bt[i] = ss.type();
>>> 1913 // else what is in_elem_bt[i]?
>>>
>>> This code is for the not-well kept secret JavaCritical, where the 
>>> native function can only take an array of primitives (checked 
>>> elsewhere that I can't find right now).  So I believe this code can 
>>> just assert ss.is_primitive() for all these cases.  Only code on 
>>> solaris sparc uses this feature, so you can run tests on sparc to 
>>> verify.
>>
>> Done. Changed all to:
>> out_sig_bt[argc++] = T_INT; out_sig_bt[argc++] = T_ADDRESS; 
>> ss.skip_array_prefix(1); // skip one '[' assert(ss.is_primitive(), 
>> "primitive type expected"); in_elem_bt[i] = ss.type(); // else what 
>> is in_elem_bt[i]?
>> Will run a sparc build & test.
>
> I don't think you need this comment anymore.
> + // else what is in_elem_bt[i]?

Yes, I agree.  Will remove those before commit.  Thanks for the final 
review!
Lois

>
>>
>>>
>>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/src/hotspot/share/classfile/systemDictionary.cpp.frames.html 
>>>
>>>
>>> 2207 if (!Signature::is_array(class_name)) {
>>>
>>>
>>> Did you try adding SignatureStream before this, to avoid the Symbol 
>>> refcounting madness?
>>
>> Yes I did try that.  However, the issue with that approach is that 
>> you may have a non signature string in the case where it is not an 
>> array.  This is the condition of the first part of the if statement 
>> on line #2207.  Here you can just simply use the Symbol* as the 
>> constraint name.  If you try to construct a SignatureStream with this 
>> non-signature Symbol* a crash occurs immediately.  SignatureStream 
>> assumes the Symbol* is a field or method signature not just a plain 
>> name for example something like "java/lang/String" without a leading 
>> 'L' or a leading '('.
>
> Oh too bad.  It looks good then.
>>
>>>
>>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/src/hotspot/share/jvmci/jvmciCompilerToVM.hpp.frames.html 
>>>
>>>
>>> hpp files shouldn't include an inline.hpp file.  Can this include 
>>> oop.hpp instead?
>>
>> I removed the inclusion of oop.inline.hpp and removed the following 
>> assert in JavaArgumentUnboxer::do_type().
>> 161     assert(arg->klass() == SystemDictionary::box_klass(type), "already checked");
>> It turns out that in the statement prior to this assert, a call is 
>> made to JavaArgumentUnboxer::next_arg(type) which already does the 
>> check for us.  Thus the "already checked" comment.  No need for a 
>> duplicate assert.
>
> Perfect.
>
>>
>>>
>>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/src/hotspot/share/oops/symbol.cpp.frames.html 
>>>
>>>
>>> Should SignatureStream arguments be const references?  Or should 
>>> they be written to?
>>
>> I was able to add a const to the SignatureStream& parameter for the 
>> static method print_class().  For print_array(), however, I was not 
>> able to since ss.skip_array_prefix() does write to 
>> SignatureStream::_type field the type after skipping the array brackets.
>
> Ok. thanks.
>
> Latest version looks good to me.
>
> Coleen
>
>>
>>>
>>> This looks really good!
>>
>> Thanks again!
>> Lois
>>
>>> Coleen
>>>
>>>
>>> On 1/24/20 4:41 PM, Lois Foltan wrote:
>>>> Please review the following enhancement to consolidate signature 
>>>> parsing code in Hotspot sources.  This change removes duplicate 
>>>> blocks of code that parse field or method signatures, provides a 
>>>> new Signature class to support basic signature queries on Symbol 
>>>> operands and enhances the SignatureStream class to parse field 
>>>> signatures in addition to methods.
>>>>
>>>> open webrev 
>>>> at:http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/ 
>>>> <http://cr.openjdk.java.net/~lfoltan/bug_jdk8230199.0/webrev/>
>>>> bug link: https://bugs.openjdk.java.net/browse/JDK-8230199
>>>> contributed-by: Lois Foltan, John Rose
>>>>
>>>> Testing: hs-tier1-8, jdk-tier1-2
>>>>
>>>> Thanks,
>>>> Lois
>>>
>>
>