Abstract

Modifying code after the compiler has generated it can be useful for both optimization and instrumentation. This paper compares the code modification systems of Mahler and pixie, and describes two new systems we have built that are hybrids of the two. This paper covers material presented at the CODE '91 International Workshop on Code Generation, Schloss Dagstuhl, Germany, May 20-24, 1991. i 1. Introduction Late code modification is the process of modifying the output of a compiler after the compiler has generated it. The reasons one might want to do this fall into two categories, optimization and instrumentation. Some forms of optimization must be performed on assembly-level or machinelevel code. The oldest is peephole optimization [11], which acts to tidy up code that a compiler has generated; it has since been generalized to include transformations on more machine-independent code [2,3]. Reordering of code to avoid pipeline stalls [4,7,18] is most often done after the code is gene...

Citations