Efficient placement of software transactional memory operations around procedure calls

A compiler system for removing redundant instructions from a program comprising atomic blocks containing software transactional memory operations, the compiler system comprising a computer executing an optimization module, the optimization module configured to:

• locate methods in the program comprising atomic blocks which contain software transactional memory operations which are able to be hoisted outside of the methods;
• hoist the software transactional memory operations which are able to be hoisted out of the methods and move the hoisted software transactional memory operations to one or more call sites for the methods;
• replace calls to the located methods with calls to specialized methods which do not contain the software transactional memory operations which are able to be hoisted;
• optimize the program, including the software transactional memory operations by removing redundancies amongst the hoisted software transactional memory operations;
• wherein the specialized methods rely on the software transactional memory operations which are able to be hoisted outside of the methods being performed before the specialized methods are called;
• wherein the methods in the program comprising atomic blocks which contain software transactional memory operations which are able to be hoisted outside of the methods comprise arguments and at least one operation to acquire a transaction manager that gives the transaction manager as a result;
• and
• wherein the specialized methods take the resulting transaction manager given by the at least one operation to acquire the transaction manager as an input variable in addition to the arguments of the methods which comprise atomic blocks which contain software transactional memory operations, and replacing occurrences of the at least one operation to acquire the transaction manager with the input variable taken by the specialized methods.

One or more computer-readable storage memory or magnetic disks containing instructions which, when executed by a computer, cause the computer to perform a method for optimizing a program comprising atomic blocks with software transactional memory instructions, the method comprising:

• receiving an intermediate representation of the program comprising atomic blocks, the intermediate representation including representations of procedures which comprise software transactional memory instructions which can be optimized outside of the procedures;
• cloning procedures which comprise software transactional memory instructions which can be optimized outside of the procedures to create procedures which rely on the software transactional memory instructions which can be optimized outside of the procedures being performed before the created procedures are called;
• wherein procedures which comprise software transactional memory instructions which can be optimized outside of the procedures further comprise arguments and instructions to acquire a transaction manager give the transaction manager as a result;
• cloning procedures comprising cloning the procedures to create procedures which take the resulting transaction manager given by the instructions to acquire the transaction manager of the cloned procedures as an input variable in addition to the arguments of the cloned procedures which comprise software transactional memory instructions which can be optimized outside of the procedures, and replacing occurrences of the instruction to acquire the transaction manager with the input variable taken by the created procedures;
• moving the software transactional memory instructions which can be optimized outside of the procedures which comprise the instruction to acquire a transaction manager to call sites for the procedures;
• wherein at least one of the one or more software transactional memory instructions which can be optimized outside of the procedures is not guaranteed to be performed in every possible execution of a procedure which contains it;
• optimizing the intermediate representation of the program by removing redundancies amongst the moved one or more software transactional memory operations which can be optimized outside of the procedures;
• and
• wherein optimizing the intermediate representation of the program comprises performing common subexpression elimination on the intermediate representation of the program.