International Business Machines Corporation

James Albert Kryka

Robert Ralph Roediger

Daniel Rodman Hicks

William Jon Schmidt

Robert John Donovan

Marc Noel Blais

Scott Thomas Robinson

Tim Clayton Muehe

David John Lambert

Roger Wayne Southwick

A method and apparatuses for allowing additional tail call optimizations. The compiler generates both optimized and non-optimized code for tail call candidates. At a later time when there is more information (e.g. regarding program bounds), a decision and a modification to the executable code is made, implementing one of the two earlier codes.

Refining tail call optimizations at link-time

An apparatus and method provide a cache for analyzed program information when no class file can be identified. When loading a class, if there is an identifiable class file for the class, the class file is checked to determine if analyzed program information is attached. If so, the analyzed program information can be directly used without the overhead of analyzing the program information again. If there is no identifiable class file for the class, a cache is checked to see if there is an entry in the cache corresponding to the class. If there is no entry in the cache corresponding to the class, the program information is analyzed and saved in a cache entry for future use. If there is an entry in the cache corresponding to the class, the analyzed program information is retrieved and used, thereby saving the time required to repeatedly analyze the program information.

Apparatus and method for caching analyzed program information

A compiler for object-oriented programming code in a language which employs run-time static initialization semantics analyzes the static initialization code to find a subset of initialization statements which must execute under all conditions, creates an pre-initialized image of the static storage using the subset, and removes statements which were pre-initialized from the final compiled code. Preferably, the compiler is a back-end compiler for the Java language, which converts Java bytecode into machine executable instructions. A static initializer method for each class is decomposed to construct a control flow graph for the method, which is then analyzed to identify statements in the source which must necessarily execute whenever the initialization method is called. The compile-time static storage image is pre-initialized to zero, except where affected by these identified statements, which are set at compile time as if the identified statements had executed. The identified statements are then removed from the code being compiled. Code size is thus reduced at the same time that performance at run time is improved as a result of not having to execute the removed initialization statements.

Object oriented method and apparatus for class variable initialization

Apparatus and a method are provided for defining visibility boundaries in compiled code of an optimizing compiler used with a digital computer for converting a source program to an object code. The source program is received and a first intermediate representation of the source program is generated. A pseudo operation representing a predetermined event is inserted in the first intermediate representation. Sequential operations of the first intermediate representation including the inserted pseudo operations are processed for defining an internal data structure of the source program. A visibility boundary for a selected variable is identified responsive to identifying a pseudo operation in the first intermediate representation.

Growing community of inventors

Rochester, MN, United States of America

James Albert Kryka