答复: 答复: 答复: HotSpot and IBM's J9 behave quite differently when processing monitorenters and monitorexits

[陈雨亭]

Hi, David,
Hi, I saw the discussions (about the verification) at https://bugs.openjdk.java.net/browse/JDK-8180581. If the specification needs to be clarified, please also include a similar example. Similarly, an object is not initialized before the " invokeinterface" instruction. At this time, HotSpot's verifier reports a verifyerror, while J9 normally runs the code. 

A verifier takes a def-use analysis to verify the bytecode, while when an object is really ready to use is not very clear.

  public void loadData() throws java.lang.Exception;
    descriptor: ()V
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: new           #19                 // class org/apache/derbyTesting/system/oe/load/ThreadInsert
         3: invokeinterface #24,  1           // InterfaceMethod org/apache/derbyTesting/system/oe/client/Load.populateAllTables:()V
         8: return
    Exceptions:
      throws java.lang.Exception

Regards,
Yuting

-----------------------
public class org.dacapo.h2.TPCC
  minor version: 0
  major version: 52
  flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
   #1 = Utf8               org/dacapo/h2/TPCC
   #2 = Class              #1             // org/dacapo/h2/TPCC
   #3 = Utf8               java/lang/Object
   #4 = Class              #3             // java/lang/Object
   #5 = Utf8               <clinit>
   #6 = Utf8               ()V
   #7 = Utf8               <init>
   #8 = Utf8               (Lorg/dacapo/parser/Config;Ljava/io/File;ZZ)V
   #9 = Utf8               java/lang/Exception
  #10 = Class              #9             // java/lang/Exception
  #11 = NameAndType        #7:#6          // "<init>":()V
  #12 = Methodref          #4.#11         // java/lang/Object."<init>":()V
  #13 = Utf8               loadData
  #14 = NameAndType        #13:#6         // loadData:()V
  #15 = Methodref          #2.#14         // org/dacapo/h2/TPCC.loadData:()V
  #16 = Utf8               iteration
  #17 = Utf8               (Ljava/lang/String;)V
  #18 = Utf8               org/apache/derbyTesting/system/oe/load/ThreadInsert
  #19 = Class              #18            // org/apache/derbyTesting/system/oe/load/ThreadInsert
  #20 = Utf8               org/apache/derbyTesting/system/oe/client/Load
  #21 = Class              #20            // org/apache/derbyTesting/system/oe/client/Load
  #22 = Utf8               populateAllTables
  #23 = NameAndType        #22:#6         // populateAllTables:()V
  #24 = InterfaceMethodref #21.#23        // org/apache/derbyTesting/system/oe/client/Load.populateAllTables:()V
  #25 = Utf8               make
  #26 = Utf8               (Lorg/dacapo/parser/Config;Ljava/io/File;Ljava/lang/Boolean;Ljava/lang/Boolean;)Lorg/dacapo/h2/TPCC;
  #27 = NameAndType        #7:#8          // "<init>":(Lorg/dacapo/parser/Config;Ljava/io/File;ZZ)V
  #28 = Methodref          #2.#27         // org/dacapo/h2/TPCC."<init>":(Lorg/dacapo/parser/Config;Ljava/io/File;ZZ)V
  #29 = Utf8               postIteration
  #30 = Utf8               preIteration
  #31 = Utf8               Code
  #32 = Utf8               Exceptions
{
  static {};
    descriptor: ()V
    flags: ACC_STATIC
    Code:
      stack=0, locals=0, args_size=0
         0: return

  public org.dacapo.h2.TPCC(org.dacapo.parser.Config, java.io.File, boolean, boolean) throws java.lang.Exception;
    descriptor: (Lorg/dacapo/parser/Config;Ljava/io/File;ZZ)V
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=5, args_size=5
         0: aload_0
         1: invokespecial #12                 // Method java/lang/Object."<init>":()V
         4: aload_0
         5: invokespecial #15                 // Method loadData:()V
         8: return
    Exceptions:
      throws java.lang.Exception

  public void iteration(java.lang.String) throws java.lang.Exception;
    descriptor: (Ljava/lang/String;)V
    flags: ACC_PUBLIC
    Code:
      stack=0, locals=2, args_size=2
         0: return
    Exceptions:
      throws java.lang.Exception

  public void loadData() throws java.lang.Exception;
    descriptor: ()V
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: new           #19                 // class org/apache/derbyTesting/system/oe/load/ThreadInsert
         3: invokeinterface #24,  1           // InterfaceMethod org/apache/derbyTesting/system/oe/client/Load.populateAllTables:()V
         8: return
    Exceptions:
      throws java.lang.Exception

  public static org.dacapo.h2.TPCC make(org.dacapo.parser.Config, java.io.File, java.lang.Boolean, java.lang.Boolean) throws java.lang.Exception;
    descriptor: (Lorg/dacapo/parser/Config;Ljava/io/File;Ljava/lang/Boolean;Ljava/lang/Boolean;)Lorg/dacapo/h2/TPCC;
    flags: ACC_PUBLIC, ACC_STATIC
    Code:
      stack=6, locals=4, args_size=4
         0: new           #2                  // class org/dacapo/h2/TPCC
         3: dup
         4: aload_0
         5: aload_1
         6: iconst_1
         7: iconst_1
         8: invokespecial #28                 // Method "<init>":(Lorg/dacapo/parser/Config;Ljava/io/File;ZZ)V
        11: areturn
    Exceptions:
      throws java.lang.Exception

  public void postIteration(java.lang.String) throws java.lang.Exception;
    descriptor: (Ljava/lang/String;)V
    flags: ACC_PUBLIC
    Code:
      stack=0, locals=2, args_size=2
         0: return
    Exceptions:
      throws java.lang.Exception

  public void preIteration(java.lang.String) throws java.lang.Exception;
    descriptor: (Ljava/lang/String;)V
    flags: ACC_PUBLIC
    Code:
      stack=0, locals=2, args_size=2
         0: return
    Exceptions:
      throws java.lang.Exception
}