STACK AREA ALLOCATING METHOD FOR COMPILER

PURPOSE: To prevent the drop of execution speed when an allocation method is applied to an architecture whose access range differs by the size of a type by inverting the allocating order of variables. CONSTITUTION: A pre-processing part 1 includes a step for distributing all the variables for every size of the type and a step for deciding whether priority is to be given to the reduction of a stack or to the execution speed in accordance with the design specification of a program. When priority is given to the stack size, a system is branched into a limb (1) and to a limb (2) when priority is given to execution speed. A stack area 20 corresponds to the limb (1) and a stack area 21 to the limb (2). In the stack area 20, allocation is executed so that the largest variable comes to the head. In the stack area 21, the variables are rearranged in an ascending order from the smallest one to the largest one and allocation is executed so that the smallest variable comes to the head. Even if the method is applied to the architecture whose access range differs by the size of the type, the small variable can be accessed with one instruction.