RFR: 8164358: [JVMCI] expose Hotspot intrinsics and HotSpotIntrinsicCandidate info to JVMCI compilers

[Dmitrij Pochepko]

Hi,

What about tests? Seems like this functionality is not covered by 
current tests. We might get it broken without noticing in case no tests 
exists.
I think at least some sanity test should be added.

In case tests are added(or already exists) looks good to me (not a 
reviewer).

Thanks,
Dmitrij
I changed it to only try reuse the declaringClass string (which has the 
most overlap): http://cr.openjdk.java.net/~dnsimon/8164358v2/ -Doug
>> On 18 Aug 2016, at 23:59, Doug Simon <doug.simon at oracle.com> wrote:
>>
>>
>>> On 18 Aug 2016, at 20:01, Christian Thalinger <cthalinger at twitter.com> wrote:
>>>
>>> src/jdk.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/CompilerToVM.java
>>>
>>>       *         [String name, Long value, ...] vmAddresses,
>>>
>>> +     *         [String name, Long value, ...] vmAddresses,
>>>
>>>       *         VMFlag[] vmFlags
>>>
>>> +     *         VMIntrinsicMethod[] vmIntrinsics
>>> Looks like a copy-paste problem.
>> Oops! Will fix.
>>
>>> src/share/vm/jvmci/jvmciCompilerToVM.cpp
>>>
>>> Why do we have to do the prev_##var##_sid == sid dance?  I guess it’s some optimization but does it really matter?
>> It cuts down the number Strings allocated by about 35% (900 vs 582). With full string interning, the savings is around 55% (415) but the overhead of using a HashSet from VM code is prohibitive. I won’t argue strongly that it makes a big difference but since the one-element cache (per VMIntrinsicMethod string field) is fast and cheap, I don’t see why not to use it. The alternative code would look something like this:
>>
>>   objArrayHandle vmIntrinsics = oopFactory::new_objArray(VMIntrinsicMethod::klass(), (vmIntrinsics::ID_LIMIT - 1), CHECK_NULL);
>>   int index = 0;
>> #define VM_SYMBOL_TO_STRING(s) java_lang_String::create_from_symbol(vmSymbols::symbol_at(vmSymbols::VM_SYMBOL_ENUM_NAME(s)), THREAD)
>> #define VM_INTRINSIC_INFO(id, kls, name, sig, ignore_fcode) {                  \
>>     instanceHandle vmIntrinsicMethod = InstanceKlass::cast(VMIntrinsicMethod::klass())->allocate_instance_handle(CHECK_NULL); \
>>     Handle kls_string = VM_SYMBOL_TO_STRING(kls);                              \
>>     Handle name_string = VM_SYMBOL_TO_STRING(name);                            \
>>     Handle sig_string = VM_SYMBOL_TO_STRING(sig);                              \
>>     VMIntrinsicMethod::set_declaringClass(vmIntrinsicMethod, kls_string());    \
>>     VMIntrinsicMethod::set_name(vmIntrinsicMethod, name_string());             \
>>     VMIntrinsicMethod::set_descriptor(vmIntrinsicMethod, sig_string());        \
>>     VMIntrinsicMethod::set_id(vmIntrinsicMethod, vmIntrinsics::id);            \
>>     vmIntrinsics->obj_at_put(index++, vmIntrinsicMethod());                    \
>>   }
>>
>>   VM_INTRINSICS_DO(VM_INTRINSIC_INFO, VM_SYMBOL_IGNORE, VM_SYMBOL_IGNORE, VM_SYMBOL_IGNORE, VM_ALIAS_IGNORE)
>> #undef VM_SYMBOL_TO_STRING
>> #undef VM_INTRINSIC_INFO
>>
>> Better?
>>
>> -Doug
>>
>>> If we don’t have to do that I would prefer is that macro would be a method (or two).
>>>
>>>> On Aug 18, 2016, at 6:50 AM, Doug Simon <doug.simon at oracle.com> wrote:
>>>>
>>>> Please review this change which allows JVMCI compilers to see what intrinsics are defined by the VM and which methods have been annotated by HotSpotIntrisicCandidate.
>>>>
>>>> https://bugs.openjdk.java.net/browse/JDK-8164358
>>>> http://cr.openjdk.java.net/~dnsimon/8164358/
>>>>
>>>> Thanks,
>>>>
>>>> -Doug