Performing register allocation of program variables based on priority spills and assignments

A system comprising:

• a processor communicably coupled to a memory;
• and
• a virtual machine being executed by the processor from the memory, the virtual machine to run a software program, the virtual machine comprising a register allocation component to:
• detect fat points during a compilation process of the software program, each detected fat point representing a program point having a high register pressure, the high register pressure to occur when a number of live program variables of the software program existing at a given program point of the software program is greater than a number of available processor registers of the computer system, wherein a live program variable comprises a program variable that maintains a value that can be used at least one of currently or later during compilation;
• choose the fat point with a highest register pressure;
• within the chosen fat point, select the live program variable having a lowest priority, wherein the lowest priority is determined in view of a live program variable cost comprising a difference between a cost of assigning the live programing variable to a processor register and a cost of sending the live program variable to memory of the computer system and in view of a sum of live program variable costs of each of other live program variables at the chosen fat point;
• and
• send the lowest priority live program variable to the memory.

A non-transitory machine-readable storage medium having instructions that, when executed by a processing device, cause the processing device to perform operations comprising:

• detecting fat points during a compilation process of a software program running on a virtual machine (VM) of a computer system comprising the processing device, each detected fat point representing a program point having a high register pressure, the high register pressure to occur when a number of live program variables of the software program existing at a given program point of the software program is greater than a number of available processor registers of the computer system, wherein a live program variable comprises a program variable that maintains a value that can be used at least one of currently or later during compilation;
• choosing the fat point with a highest register pressure;
• within the chosen fat point, selecting the live program variable having a lowest priority, wherein the lowest priority in view of a live program variable cost comprising a difference between a cost of assigning the live programing variable to a processor register and a cost of sending the live program variable to memory of the computer system and in view of a sum of live program variable costs of each of other live program variables at the chosen fat point;
• and
• sending the lowest priority live program variable to the memory of the computer system.