diff options
| author | Alexander Kriegisch <Alexander@Kriegisch.name> | 2023-01-07 10:36:08 +0100 |
|---|---|---|
| committer | Alexander Kriegisch <Alexander@Kriegisch.name> | 2023-01-07 14:07:27 +0100 |
| commit | c8b9568a8577d2af0f1449eec729784b0dcaa484 (patch) | |
| tree | c7af67ed62acd67c72843c6451dd116e61c1d112 /weaver/src | |
| parent | 438eb9301014ffb63bbcbae4df684a2907ac91d5 (diff) | |
| download | aspectj-c8b9568a8577d2af0f1449eec729784b0dcaa484.tar.gz aspectj-c8b9568a8577d2af0f1449eec729784b0dcaa484.zip | |
BcelTypeMunger.mungeMethodDelegate: only use 'synchronized' when necessary
Relates to #198. Now, we create a delegate method body which basically
looks as follows:
public void methodOne() {
if (this.ajc$instance$MyAspect$MyMixin == null) {
synchronized(this) {
if (this.ajc$instance$MyAspect$MyMixin == null) {
this.ajc$instance$MyAspect$MyMixin = MyAspect.aspectOf().createImplementation(this);
}
}
}
this.ajc$instance$MyAspect$MyMixin.methodOne();
}
The idea for the outer null check is from @aclement, see
https://github.com/eclipse/org.aspectj/pull/205#issuecomment-1371556080.
Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>
Diffstat (limited to 'weaver/src')
| -rw-r--r-- | weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java | 28 |
1 files changed, 25 insertions, 3 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 0ecad3606..3463d444a 100644 --- a/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java +++ b/weaver/src/main/java/org/aspectj/weaver/bcel/BcelTypeMunger.java @@ -1436,6 +1436,26 @@ public class BcelTypeMunger extends ConcreteTypeMunger { InstructionList body = new InstructionList(); InstructionFactory fact = gen.getFactory(); + // Create a delegate method body which basically looks as follows: + // + // public void methodOne() { + // if (this.ajc$instance$MyAspect$MyMixin == null) { + // synchronized(this) { + // if (this.ajc$instance$MyAspect$MyMixin == null) { + // this.ajc$instance$MyAspect$MyMixin = MyAspect.aspectOf().createImplementation(this); + // } + // } + // } + // this.ajc$instance$MyAspect$MyMixin.methodOne(); + // } + + // Before synchronising on 'this', perform a preliminary null check on the delegate field. Only if it is null, + // it makes sense to synchronise, then check for null again and initialise the delegate, if null. + body.append(InstructionConstants.ALOAD_0); + body.append(Utility.createGet(fact, munger.getDelegate(weaver.getLazyClassGen().getType()))); + InstructionBranch outerIfNonNull = InstructionFactory.createBranchInstruction(Constants.IFNONNULL, null); + body.append(outerIfNonNull); + // Wrap delegate field initialisation in 'synchronized(this)' block - MONITORENTER (beginning of 'try') body.append(InstructionConstants.ALOAD_0); body.append(InstructionConstants.MONITORENTER); @@ -1444,8 +1464,8 @@ public class BcelTypeMunger extends ConcreteTypeMunger { // 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); + InstructionBranch innerIfNonNull = InstructionFactory.createBranchInstruction(Constants.IFNONNULL, null); + body.append(innerIfNonNull); // Create and store a new instance body.append(InstructionConstants.ALOAD_0); // 'this' is where we'll store the field value @@ -1494,7 +1514,7 @@ public class BcelTypeMunger extends ConcreteTypeMunger { // Wrap delegate field initialisation in 'synchronized(this)' block - MONITOREXIT (end of 'try') InstructionHandle ifNonNullElse = body.append(InstructionConstants.ALOAD_0); - ifNonNull.setTarget(ifNonNullElse); + innerIfNonNull.setTarget(ifNonNullElse); body.append(InstructionConstants.MONITOREXIT); // There was no error in the 'synchronized(this)' block -> jump to first instruction after exception handler @@ -1519,6 +1539,8 @@ public class BcelTypeMunger extends ConcreteTypeMunger { InstructionHandle afterTryCatch = body.append(InstructionConstants.ALOAD_0); // Tell 'gotoAfterTryCatch' where to find the first statement after the exception handler gotoAfterTryCatch.setTarget(afterTryCatch); + // The outer delegate field null check should also jump to the same place, if the delegate field is not null + outerIfNonNull.setTarget(afterTryCatch); body.append(Utility.createGet(fact, munger.getDelegate(weaver.getLazyClassGen().getType()))); // args |