CODEWITHSUNDEEP
javaeclipse
mark
mark

Reputation: 62896

How to ensure the methods are not inlined by the java compiler?

For testing purposes I need to be sure that certain methods are not inlined when the respective code is compiled to produce the .class files.

How do I do it in Eclipse?

EDIT

For those who really need to know why, before they tell how, here is the explanation - I am testing a code, which examines and manipulates JVM byte code. This is why I want sometimes to avoid method inlining.

Upvotes: 0

Views: 197

Answers (3)

Boann
Boann

Reputation: 50061

Java methods are never inlined when producing the .class files (only by an optimizing JVM at run time), so you have nothing to worry about.

Upvotes: 1

Dave Newton
Dave Newton

Reputation: 160321

You don't; you have very little control over how the compiler and JIT optimize bytecode.

It's not clear to me why you'd want to do this, though.

Note that various JVM implementations may allow tweaking, e.q., -XX:MaxInlineSize= in HotSpot might be set to an impossibly-low number meaning no methods would be inlined. There may be an equivalent option in the Eclipse compiler, but I'd be wary.

Upvotes: 4

corsiKa
corsiKa

Reputation: 82599

When it comes to Java inlining functions, you are entirely at the whim of the compiler. You have no say in it whatsoever.

There are some various metrics that it uses to determine if something should be inlined. I believe one of these is the number of bytecode instructions in the method. So if you had a method like this:

void foo() {
    if(SOME_GLOBAL_BOOLEAN_THATS_ALWAYS_FALSE) {
        // lots of statements here
    }
    // code here
}

You might be able to reduce the chance of it inlining on you, provided you were clever enough in your if statement to make sure it wasn't going to optimize it out on you.

Upvotes: -1

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