On Dec 6, 2010, at 11:29 AM, Daniel D. Daugherty wrote:
src/share/vm/prims/jvmtiEnv.cpp
  Since JVM/TI version 1.0, 1.1 and (presumably) 1.2 are compatible
  with each other, you don't need to do this check. The relevant
  part of the JVM/TI spec is:

  
http://download.oracle.com/javase/6/docs/platform/jvmti/jvmti.html#jvmtiEnvAccess

  The key sentence is:

  > The returned environment may have a different version than the
  > requested version but the returned environment must be compatible.

  If a client asks for version 1.0 or version 1.1, then it is okay
  to return version 1.2 as long as the common parts between those
  versions are compatible. If a client running on JDK5 or JDK6 is
  smart enough to ask for JVM/TI version 1.2, then it can be allowed
  to have it.

Understood that the spec allows us return a different version, but it doesn't require it. I'd think we'd want to leave JDK6 alone as much as possible, but I'll defer to your opinion in this matter.

src/share/vm/prims/jvmtiExport.cpp
  I don't think you need these changes either.

Right - unless we do want to keep the version constant in jdk6 (and jdk5 maybe someday).

src/share/vm/prims/jvmtiH.xsl
  This change just adds JVMTI_VERSION_1_2. It does not change the
  JVMTI_VERSION value to the 1.2 version, but it should.

That macro gets created using the major/minor fields. Excerpt from the generated jvmti.hpp:
enum {
    JVMTI_VERSION_1   = 0x30010000,
    JVMTI_VERSION_1_0 = 0x30010000,
    JVMTI_VERSION_1_1 = 0x30010100,
    JVMTI_VERSION_1_2 = 0x30010200,

JVMTI_VERSION = 0x30000000 + (1 * 0x10000) + (2 * 0x100) + 1 /* version: 1.
2.1 */
};


src/share/vm/prims/jvmtiEnvBase.hpp
  You should add JDK17_JVMTI_VERSION to the enum set here. You should
  also add a declaration for JvmtiEnvBase::use_version_1_2_semantics()
  here.

src/share/vm/prims/jvmtiEnvBase.cpp
You should add a definition for JvmtiEnvBase::use_version_1_2_semantics()
  here.

I'll do these.

If a JVM/TI version simply adds new functions, then nothing needs to
be done. An older agent that asks for JVM/TI version 1.0 or JVM/TI
version 1.1 won't know about or try to use the new function.

However, if a new JVM/TI version changes semantics of an existing function,
then a little more hoop jumping is needed.

What kind of hoop-jumping, exactly? I may have to find these hoops and jump through them in the near future for a different fix.

--
- Keith

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