Class splitting in object-oriented environments

Abstract

Embodiments of the present invention disclose a method, computer program product, and system for class splitting in object-oriented environments in which objects are created by classes. Data is analyzed, in response to generating an instance of an original class in a code component. Fields are separated into sets based on the code paths that access the fields. A split class is generated for a set of fields which shares a common interface with the original class. Cells are replaced in the code component to the original class with a split class.

What is claimed is: 
     
         1 . A computer-implemented method for class splitting in object-oriented environments in which objects are created by classes, the method comprising:
 analyzing data, in response to generating an instance of an original class in a code component;   separating fields into sets based on the code paths that access the fields;   generating a split class for a set of fields which shares a common interface with the original class; and   replacing calls in the code component to the original class with a split class.   
     
     
         2 . The method of  claim 1 , wherein analyzing data further comprises:
 analyzing code paths in the original class in the code component; and   analyzing fields, wherein the fields are accessed by the code paths.   
     
     
         3 . The method of  claim 1 , wherein generating a split class includes adding code for paths utilized by the split class. 
     
     
         4 . The method of  claim 1 , wherein generating a split class includes one or more of:
 adding shared code which is copied into any split classes using the shared code; and   the shared code is accessed by the split class from the original class.   
     
     
         5 . The method of  claim 1 , wherein a decision to generate a split class is taken at one or more of: a build time; a runtime, and the decision to generate further comprises one or more of: reducing the amount of code in a most common paths and reducing the size of a most common type object. 
     
     
         6 . The method of  claim 1 , wherein replacing calls in the code component is carried out dynamically by checking instance types of an argument to choose which split class to instantiate. 
     
     
         7 . The method of  claim 1 , wherein replacing calls in the code component is carried out before running the code component, and calls are statically directed to a split class. 
     
     
         8 . The method of  claim 1 , wherein analyzing data is carried out to optimize one or both of code and data. 
     
     
         9 . The method of  claim 1 , wherein analyzing data is carried out by one or more of: statically at build time; and dynamically at runtime via a just in time (JIT) compiler. 
     
     
         10 . The method of  claim 1 , wherein a split class eliminates decision points for paths not taken for that instance of the object and unused fields are removed from split classes. 
     
     
         11 . The method of  claim 1 , a split class is generated for a first constructor that take different arguments from a second constructor of the original class, and calls to the first constructor are replaced by calls to the split class. 
     
     
         12 . The method of  claim 1 , wherein a single split class is generated in response to a majority of calls using a single code path. 
     
     
         13 . The method of  claim 1 , wherein separating fields into sets further comprises performing escape analysis based on one or more fields grouped into a plurality of sets reachable from each code path. 
     
     
         14 . A computer program product for class splitting in object-oriented environments in which objects are created by classes, the computer program product comprising:
 one or more computer-readable storage media and program instructions stored on the one or more computer-readable storage media, the program instructions comprising:   instructions to analyze data, in response to instructions to generate an instance of an original class in a code component;   instructions to separate fields into sets based on the code paths that access the fields;   instructions to generate a split class for a set of fields which shares a common interface with the original class; and   instructions to replace calls in the code component to the original class with a split class.   
     
     
         15 . The computer program product of  claim 14 , wherein analyzing data further comprises:
 instructions to analyze code paths in the original class in the code component; and   instructions to analyze fields, wherein the fields are accessed by the code paths.   
     
     
         16 . The computer program product of  claim 14 , wherein instructions to generate a split class includes adding code for paths utilized by the split class. 
     
     
         17 . The computer program product of  claim 14 , wherein instructions to generate a split class includes one or more of:
 adding shared code which is copied into any split classes using the shared code; and   the shared code is accessed by the split class from the original class.   
     
     
         18 . The computer program product of  claim 14 , wherein instructions to generate a split class is executed at one or more of: a build time; a runtime, and the decision to generate further comprises one or more of: reducing the amount of code in a most common paths and reducing the size of a most common type object. 
     
     
         19 . The computer program product of  claim 14 , wherein replacing calls in the code component is carried out dynamically by checking instance types of an argument to choose which split class to instantiate. 
     
     
         20 . A computer system for class splitting in object-oriented environments in which objects are created by classes, the computer system comprising:
 one or more computer processors;   one or more computer-readable storage media;   program instructions stored on the computer-readable storage media for execution by at least one of the one or more processors, the program instructions comprising:   instructions to analyze data, in response to instructions to generate an instance of an original class in a code component;   instructions to separate fields into sets based on the code paths that access the fields;   instructions to generate a split class for a set of fields which shares a common interface with the original class; and   instructions to replace calls in the code component to the original class with a split class.