A method in a Just-In-Time, JIT, compiler for compiling code in a JIT-compiler for a heterogeneous multiprocessor system is provided. The method comprises compiling a snippet of input code, whereby one or more compiled code snippets are generated for the snippet of input code. The one or more compiled code snippets are tagged with one or more snippet specific characteristics. One or more compiled code snippets are selected from the compiled code snippets, based on said snippet specific characteristics. The one or more selected compiled code snippets are executed on one or more of the plurality of processors. While executing, run-time data is gathered, where the gathered data is tagged for which processor in the heterogeneous multiprocessor system it is related to.