tools.emitter.jvm

A JVM bytecode generator for ASTs compatible with tools.analyzer[.jvm].

• Example Usage
• Differences From Clojure
• Releases and Dependency Information
• Changelog
• Developer Information
• License

Example Usage

user=> (require '[clojure.tools.emitter.jvm :as e])
nil
user=> (e/eval '(+ 1 2))
3
user=> (e/eval '(+ 1 2) {:debug? true})
// class version 50.0 (50)
// access flags 0x31
public final class user$fn__6242 extends clojure/lang/AFunction  implements clojure/lang/IFn$L  {

  // compiled from: user$fn__6242

  // access flags 0x9
  public static <clinit>()V
    RETURN
    MAXSTACK = 0
    MAXLOCALS = 0

  // access flags 0x1
  public <init>()V
    ALOAD 0
    INVOKESPECIAL clojure/lang/AFunction.<init> ()V
    RETURN
    MAXSTACK = 1
    MAXLOCALS = 1

  // access flags 0x1
  public invokePrim()J
   L0
    LINENUMBER 1 L0
    LCONST_1
    LDC 2
    ACONST_NULL
    ASTORE 0
    INVOKESTATIC clojure/lang/Numbers.add (JJ)J
    LRETURN
    LOCALVARIABLE this Lclojure/lang/AFunction; L0 L0 0
    MAXSTACK = 5
    MAXLOCALS = 1

  // access flags 0x1
  public invoke()Ljava/lang/Object;
    ALOAD 0
    INVOKEVIRTUAL user$fn__6242.invokePrim ()J
    INVOKESTATIC clojure/lang/RT.box (J)Ljava/lang/Number;
    ARETURN
    MAXSTACK = 2
    MAXLOCALS = 1
}
3
user=> (e/load "clojure.pprint")
nil
user=> (clojure.pprint/pprint 1)
1

Differences From Clojure

While the bytecode produced by tools.emitter.jvm is similar to the one produces by Clojure itself, there are some differences:

• tools.emitter.jvm is capable of clearing locals closed over by loops, in the loop exit path
• tools.emitter.jvm clears the "this" local before the last tail call in a method, see CLJ-1250
• tools.emitter.jvm clears unused locals after their creation
• tools.emitter.jvm hoists loop and try bodies into separate methods rather than wrapping them in a fn, see CLJ-701
• tools.emitter.jvm emits keyword invoke callsites only when the keyword is not namespaces, see CLJ-1469
• tools.emitter.jvm emits typed bytecode, enforcing any explicit tag, this breaks some functions in clojure.core like ns-interns. This behaviour might be reconsidered in the future.
• tools.emitter.jvm handles CLJ-1330

SPONSORSHIP

• Cognitect (http://cognitect.com/) is sponsoring tools.emitter.jvm development (https://groups.google.com/d/msg/clojure/iaP16MHpX0E/EMtnGmOz-rgJ)
• Ambrose BS (https://twitter.com/ambrosebs) has sponsored tools.emitter.jvm development in his typed clojure campaign (http://www.indiegogo.com/projects/typed-clojure).

YourKit

YourKit has given an open source license for their profiler, greatly simplifying the profiling of tools.emitter.jvm performance.

YourKit is kindly supporting open source projects with its full-featured Java Profiler. YourKit, LLC is the creator of innovative and intelligent tools for profiling Java and .NET applications. Take a look at YourKit's leading software products:

• YourKit Java Profiler and
• YourKit .NET Profiler.

Releases and Dependency Information

Latest stable release: 0.1.0-beta4

• All Released Versions

• Development Snapshot Versions

Leiningen dependency information:

[org.clojure/tools.emitter.jvm "0.1.0-beta4"]

Maven dependency information:

<dependency>
  <groupId>org.clojure</groupId>
  <artifactId>tools.emitter.jvm</artifactId>
  <version>0.1.0-beta4</version>
</dependency>

Changelog

Developer Information

• GitHub project

• API index

• Bug Tracker

• Continuous Integration

• Compatibility Test Matrix

License

Copyright © 2013-2014 Nicola Mometto, Rich Hickey & contributors.

Distributed under the Eclipse Public License, the same as Clojure.