RFR (L) JDK-8230199: consolidate signature parsing code in HotSpot sources
Lois Foltan
lois.foltan at oracle.com
Tue Jan 28 20:50:42 UTC 2020
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.
>
> 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 '('.
>
> 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.
>
> 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.
>
> 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
>
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