| 摘要 |
In a compiler within a computing system, user definition webs are built for local variables in a subroutine. For each user definition web in which a first local variable is used, if there is a use of the first local variable for which there is no definition on at least one path to an entry point of the subroutine, a definition of the local variable is inserted at every entry point of the subroutine from which the use can be reached. Further, in the preferred embodiment, for each user definition web in which a first local variable is used, if there is a use of the first local variable for which there is no definition on at least one path to an entry point of the subroutine and if no definition can reach the use, the web is reported as definitely undefined. For each user definition web in which a first local variable is used, if there is a use of the first local variable for which there is no definition and if a definition can reach the use, the web is reported as possibly undefined.
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