Abstract: A program feature set is compared to a processor feature set. The comparison may be performed in response to restoring the program onto a system or requesting its execution. The processor feature set represents zero, one or more optional hardware features supported by the processor, whereas the program feature set represents zero, one or more optional hardware features the program relies upon in its generated code. Comparison of the feature sets determines whether a particular program may run on a particular processor. Programs may be automatically or manually rebuilt to achieve full compatibility. If the comparison indicates that the program requires a feature not supported by the processor, the program is rebuilt based on the processor feature set. Alternatively, the program may be rebuilt in response to a rebuild request, rather than the comparison. The program is preferably rebuilt from an intermediate representation (IR) stored with or locatable from the program.

Abstract: A run-time feature set of a process or a thread is generated and compared to at least one processor feature set. Each processor feature set represents zero or more optional hardware features supported by one or more processors, whereas the run-time feature set represents zero or more optional hardware features the process or thread relies upon. The comparison of the feature sets determines whether a particular process or thread may run on a particular processor, even in a heterogeneous processor environment. A system task dispatcher assigns the process or thread to execute on one or more processors indicated by the comparison as being compatible with the process or thread. When a new feature is added to the process or thread, the run-time feature set is updated and again compared to at least one processor feature set. The system task dispatcher reassigns the process or thread if necessary.

Abstract: Methods and apparatus are disclosed for improved loop unrolling by a compiler. A large class of loops exists for which effective loop unrolling has not previously been performed because they are too large to be completely unrolled, but which do not have a single hot trace that covers an entire loop iteration. The present invention recognizes such loops that have partial hot traces identified using profile data. A set of instructions which constitute a proper superset of the hot trace and a proper subset of the entire loop, and which forms a complete loop iteration is identified. This set of instructions can then be unrolled without unrolling the entire loop.