diff options
| -rw-r--r-- | weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java b/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java index 9e56d9e88..0ecad3606 100644 --- a/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java +++ b/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java @@ -1436,8 +1436,13 @@ public class BcelTypeMunger extends ConcreteTypeMunger { InstructionList body = new InstructionList(); InstructionFactory fact = gen.getFactory(); - // getfield + // Wrap delegate field initialisation in 'synchronized(this)' block - MONITORENTER (beginning of 'try') body.append(InstructionConstants.ALOAD_0); + body.append(InstructionConstants.MONITORENTER); + + // The JVM spec requires us add an exception handler ensuring MONITOREXIT in case of an exception inside the + // synchronized block, see https://docs.oracle.com/javase/specs/jvms/se17/html/jvms-3.html#jvms-3.14. + InstructionHandle tryStart = body.append(InstructionConstants.ALOAD_0); body.append(Utility.createGet(fact, munger.getDelegate(weaver.getLazyClassGen().getType()))); InstructionBranch ifNonNull = InstructionFactory.createBranchInstruction(Constants.IFNONNULL, null); body.append(ifNonNull); @@ -1487,9 +1492,33 @@ public class BcelTypeMunger extends ConcreteTypeMunger { body.append(Utility.createSet(fact, munger.getDelegate(weaver.getLazyClassGen().getType()))); } - // if not null use the instance we've got + // Wrap delegate field initialisation in 'synchronized(this)' block - MONITOREXIT (end of 'try') InstructionHandle ifNonNullElse = body.append(InstructionConstants.ALOAD_0); ifNonNull.setTarget(ifNonNullElse); + body.append(InstructionConstants.MONITOREXIT); + + // There was no error in the 'synchronized(this)' block -> jump to first instruction after exception handler + InstructionBranch gotoAfterTryCatch = new InstructionBranch(Constants.GOTO, null); + InstructionHandle tryEnd = body.append(gotoAfterTryCatch); + + // Exception handler (logical 'catch') for the 'synchronized(this)' block ensures that MONITOREXIT is also called + // in case of an error + InstructionHandle catchStart = body.append(InstructionConstants.ALOAD_0); + body.append(InstructionConstants.MONITOREXIT); + InstructionHandle catchEnd = body.append(InstructionConstants.ATHROW); + + // Add exception handler for 'synchronized(this)' block + mg.addExceptionHandler(tryStart, tryEnd.getPrev(), catchStart, null, false); + + // CAVEAT: Add an extra, self-referential exception handler entry. I.e., the handler handles its own exceptions. + // According to https://docs.oracle.com/javase/specs/jvms/se17/html/jvms-3.html#jvms-3.14, this is required, and + // Javac also creates code like this, which is why we are mimicking it. + mg.addExceptionHandler(catchStart, catchEnd.getPrev(), catchStart, null, false); + + // if not null use the instance we've got + InstructionHandle afterTryCatch = body.append(InstructionConstants.ALOAD_0); + // Tell 'gotoAfterTryCatch' where to find the first statement after the exception handler + gotoAfterTryCatch.setTarget(afterTryCatch); body.append(Utility.createGet(fact, munger.getDelegate(weaver.getLazyClassGen().getType()))); // args |