Abstract not found

Real-time programmers have to deal with the problem of relating timing constraints associated with source code to sequences of machine instructions. This paper describes an environment to assist users inthe specification and analysis of timing constraints. A timing analyzer predicts the best and worst case bounds for these constrained portions of code. A user interface for this timing analyzer was developed to depict whether these constraints were violated or met. Auser is allowed to specify timing constraints within the source code of a C program. The user interface also provides three different methods for interactively selecting portions of programs. After each selection the corresponding bounded times, source code lines, and machine instructions are automatically displayed. Users are pre vented from only selecting portions of the program for which timing bounds cannot be obtained. In addition, a technique is presented that allows the timing analysis to scale efficiently with complex functions and loops. The result is a user-friendly environment that supports the user specification and analysis of timing constraints at a high (source code) level and retains the accuracy of low (machine code) level analysis. 1.

Class specific optimizations are compiler optimizations specified by the class implementor to the compiler. hey allow the compiler to take advantage of the semantics of the particular class so as to produce better code. ptimizations of interest include the strength reduction of class::array address calculations, elimination of large temporaries, and the placement of asynchronous send/recv calls so as to achieve computation /communication overlap. e will outline our progress towards the implementation of a C compiler capable of incorporating class specific optimizations. ntro uction During the implementation of complex systems in C++, particularly numerical ones, the implementor typically encounters performance problems of varying difficulty. These difficulties usually relate to the lack of semantic understanding the C++ compiler has of the user defined classes. This problem was recently studied in [2] where the potential solution of class based optimizations was put forth. A class bas...

Most of the time, faced with a time/space trade-off, a compiler writer will choose to optimize time, even at the cost of space. This was not always the case. Early in the history of computers, programmers would try everything they could think of to reduce the size of their code to get it to fit in the computer’s constrained space. As memory and