A method and several variants for using information about the scope of access of objects acted upon by
mutual exclusion, or mutex, locks to transform a
computer program by eliminating locking operations from the program or simplifying the locking operations, while strictly performing the
semantics of the original program. In particular, if it can be determined by a
compiler that the object locked can only be accessed by a single thread it is not necessary to perform the "acquire" or "release" part of the locking operation, and only its side effects must be performed. Likewise, if it can be determined that the side effects of a locking operation acting on a variable which is locked in multiple threads are not needed, then only the locking operation, and not the side effects, needs to be performed. This simplifies the locking operation, and leads to faster programs which use fewer computer processor resources to execute; and programs which perform fewer
shared memory accesses, which in turn not only causes the optimized program, but also other programs executing on the same computing
machine to execute faster. The method also describes how information about the
semantics of the locking operation side effects and the information about the scope of access can also be used to eliminate performing the
side effect parts of the locking operation, thereby completely eliminating the locking operation. The method also describes how to analyze the program to compute the necessary information about the scope of access. Variants of the method show how one or several of the features of the method may be performed.