On 6/28/16 11:19, Daniel D. Daugherty wrote:
On 6/28/16 10:37 AM, [email protected] wrote:
Hi Harold,
Thank you again for the comments!
This is the updated webrev:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.5/
make/test/JtregNative.gmk
No comments.
src/share/vm/classfile/modules.hpp
No comments.
src/share/vm/classfile/modules.cpp
L826: assert(h_loader.is_null() ||
java_lang_ClassLoader::is_subclass(h_loader->klass()),
L827: "Class loader is not a subclass of
java.lang.ClassLoader");
nit: indent on L827 is off by 1 space
Thanks, will fix.
I'll have to check the upper layers of this API, but if an
agent can pass a bad 'class_loader' parameter and get this
assert() to fire, then that's not good. Hopefully a bad
'class_loader' parameter is caught at a higher layer.
Not sure, what do you mean.
Do you mean the generated JVMTI upper layer or the JvmtiEnv::GetNamedModule?
Probably, the generated code.
Update: Yes, passing a non-NULL jobject as the class_loader
parameter
when the jobject does not refer to a "class loader" is caught
at the upper layer.
The upper layer does not check that it is a class loader, just for non-NULL.
I think, it is good to have an assert here to double-checks the
pre-conditions as other caller can be added later.
But I'm Ok to get rid of it if you suggest.
L828: assert(package_str != NULL, "the package_str should not be
NULL");
Same concern about the package_str parameter.
Update: Yes, the generated JVM/TI glue code should catch a
NULL package_name/package_str at the upper layers.
Yes, but this assert is intentional as above.
src/share/vm/prims/jvmti.xml
L6550: <param id="module_ptr">
L6551: <outptr><jobject/></outptr>
L6552: <description>
L6553: On return, points to a
<code>java.lang.reflect.Module</code> object.
L6554: </description>
L6555: </param>
The above wording doesn't allow for module_ptr to be NULL which
is a mismatch with the description.
I disagree (or maybe I got it incorrectly).
Pointing to NULL and be NULL is different.
It is not allowed for the module_ptr to be NULL but Ok to pint to NULL
on return.
L2518: function can be used to map class loader and package
name to a module.
Typo: 'map class loader and package name'
-> 'map a class loader and a package name'
Good catch, thanks!
Will fix.
src/share/vm/prims/jvmtiEnv.cpp
L204: // class_loader - NULL is a valid value, must be pre-checked
L205: // package_name - pre-checked for NULL
L206: // module_ptr - pre-checked for NULL
The jvmti.xml file doesn't mark package_name or module_ptr
with <nullok> so both of those should be checked by the
generated glue code.
class_loader is marked with <nullok> so a NULL class_loader
will get to here:
L217: jobject module = Modules::get_named_module(h_loader,
package_name, THREAD);
and it looks like all the code paths in get_named_module()
properly account for both NULL and non-NULL h_loader. Cool.
Good.
Thank you for checking.
test/serviceability/jvmti/GetNamedModule/MyPackage/GetNamedModuleTest.java
L42: System.err.println("java.library.path:"
nit: a space between the ':' and '"' would make the
output more readable
Thanks, will fix.
test/serviceability/jvmti/GetNamedModule/libGetNamedModuleTest.c
L81: res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **)
&jvmti),
L82: JVMTI_VERSION_1_1);
I was expecting this test to ask for the JVM/TI version that
includes support for GetAllModules() and GetNamesModule().
Looks like that is version 9.0.0 or newer aka JVMTI_VERSION_9.
You are right.
Will fix.
L360: if (module != NULL || mod_name !=NULL) {
bit: space after '!=' and before NULL
Thanks, will fix.
Has someone checked the generated glue code for completeness and
proper checks?
I checked it some time ago.
But will double-check it.
Thank you for the review and detailed comments!
Serguei
Dan
Thanks,
Serguei
On 6/28/16 07:32, harold seigel wrote:
Hi Serguei,
Looks good.
1. In modules.cpp, the first assert in get_named_module() has the
wrong function name:
825 assert(ModuleEntryTable::javabase_defined(),
826 "Attempt to call *get_module_by_package_name* before java.base
is defined");
2. Also, is a check needed to ensure that package_str is not null?
3. Is the ResourceMark(THREAD) needed at line 824?
Thanks, Harold
On 6/28/2016 4:54 AM, [email protected] wrote:
Hi David,
Thank you for the comments!
I agree with you.
Updated Hotspot webrev:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.4/
Thanks,
Serguei
On 6/27/16 22:06, David Holmes wrote:
Hi Serguei,
Overall this looks a lot clearer/simpler.
On 28/06/2016 2:20 PM, [email protected] wrote:
On 6/27/16 21:08, [email protected] wrote:
Please, review the Jigsaw fix for the enhancement:
https://bugs.openjdk.java.net/browse/JDK-8159145
The Hotspot webrev:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.3/
Are there intended to be other callers of
Module::get_named_module? If not it seems odd to go to all the
trouble of throwing exceptions, just to have the caller clear them
and return an error code. Or you could move all that argument
checking code into the JVMTI function directly - if called
internally you would just assert that arguments are as expected.
src/share/vm/prims/jvmti.xml
+ otherwise the <code>NULL</code> is returned.
Delete "the".
Otherwise all looks good to me.
The Jdk webrev is the same:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.jdk1/
Sorry, the Jdk webrev changed as well:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.jdk3/
Looks fine.
Thanks,
David
Thanks,
Serguei
Summary:
This is the review round #3.
Alan suggested to replace the function GetModuleByPackageName
with
the GetNamedModule.
New function will return NULL if the package is not in a module
defined to the class loader.
It simplifies the API and makes it easier to specify.
JVM TI agents that instrument code in named modules need the
Module
at class load time.
One question that came from the function semantics change.
I had to implement the Modules::get_named_module() from scratch
independently of the existing
Modules::get_module_by_package_name() and Modules::get_module().
The issue is that the Modules::get_module() can return the
unnamed
module whereas the
JVMTI helper Modules::get_named_module() should return NULL
instead
of the unnamed module.
Please, let me know if it is Ok or if you have better ideas
how to
share the code.
This is the Summary from review round #1:
One way to do this is by introducing a new ClassFileLoadHook that
takes an additional parameter but this approach is disruptive.
The alternative option is a JVM TI function that maps a
classloader
+ package name to a module.
We were initially not confident with this approach so we
introduced
it as JVM function JVM_GetModuleByPackageName.
Based on experience to date then this approach seems okay and so
this function needs to be promoted to a JVMTI function.
It includes new jtreg test with native JVMTI agent.
Testing:
Run newly developed jtreg test.
Thanks,
Serguei
