Hi Mandy,
The API looks fine to me.
Note that there is an opportunity for a follow-up optimization of the
StackFrameInfo::getDescriptor() case. When MemberName's 'type' field is
filled by native expandFromVM() it is usually filled with the descriptor
string. MemberName::getMethodType() then parses this string into a
MemberType, resolving all the types. So when
StackFrameInfo::getDescriptor() is called, the descriptor string is 1st
parsed into MethodType and then formatted back to the descriptor. By
introducing new method into package-private MemberName - say
getMethodDescriptorString(), this intermediate conversion could often be
avoided (for example, if getMethodDescriptorString() was called before
getMethodType() on an instance of MethodName).
Regards, Peter
On 09/01/2017 07:39 AM, mandy chung wrote:
Updated webrev:
http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8186050/webrev.01/index.html
This introduces two new methods, StackFrame::getMethodType and
StackFrame::getDescriptor.
Mandy
On 8/30/17 12:25 AM, Remi Forax wrote:
Hi Mandy,
thanks for taking care of this.
In my opinion, we should provide both getMethodType() and
getDescriptor(),
getDescriptor() is handy for logging (finding the right overload when
line numbers are not present) and getMethodType() is the one you
whant if you want to inspect the runtime view of the stack frames
(and by example interact with java.lang.invoke). For me, it's the
same reason that give us getDeclaringClass() and getClassName() in
the current API.
So getDescriptor() can be called with no restriction but
getMethodType() requires RETAIN_CLASS_REFERENCE.
regards,
Rémi
----- Mail original -----
De: "mandy chung" <[email protected]>
À: "core-libs-dev" <[email protected]>
Envoyé: Mardi 29 Août 2017 00:57:28
Objet: Review Request JDK-8186050: StackFrame should provide the
method signature
Method signature is missing in the StackFrame API. This proposes to add
StackFrame::getMethodDescriptor method to return the method descriptor
in a stack frame.
Webrev at:
http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8186050/webrev.00/index.html
There are a couple options how to present the method signature in the
API level:
1. Class<?>[] getParameterTypes() and Class<?> getReturnTypes()
similiar
to what java.lang.reflect.Method has.
2. java.lang.invoke.MethodType
3. a String representation (i) comma-separated list of the method's
formal parameter types (ii) bytecode method descriptor as specified
in JVMS
Returning Class<?> instance should require to add a new StackWalker
option to access to the parameter types and return type for option #1
and #2. StackFrame::getDeclaringClass requires the stack walker to have
the RETAIN_CLASS_REFERENCE capability.
Option #2 returning MethodType is handy while java.lang would reference
a type in java.lang.invoke.
Option #3 requires the caller to parse the return string and call
Class.forName to get the Class<?> instance. OTOH
MethodType::fromMethodDescriptorString method that returns MethodType
from a bytecode method descriptor string.
Method signature is for information for typical cases. Getting Class<?>
for the parameter types and return type would be a niche case. I think
returning the method descriptor string is a good option - keep the API
simple and can use MethodType::fromMethodDescriptorString to get back
the types if needed.
thanks
Mandy
