Motorola SC140 user manual Local Versus Global Optimization Exercise, Local Optimization

Compiler Support on StarCore

3 Local Versus Global Optimization Exercise

The local versus global optimization exercise shows the difference between two C compiler options: local optimization (the default) and global optimization. Local optimization compiles each file of the project individually as represented in Figure 4. Global optimization acts as a global binder that links all the intermediate representation (IR) files into one file before optimizing the application. Since all the application code information is available, this approach enables further optimizations beyond those achieved using local optimization alone. (Compilation takes longer when global optimization is enabled.) Global optimization compilation flow is represented in Figure 5.

StarCore C Compiler

C files

.c, .h

Cfiles

.c, .h

Cfiles

.c, .h

Local

Optimization

Ccompiler Front End

IR files

.obj

Optimizer icode

Ccompiler Front End

IR files

.obj

Optimizer icode

Ccompiler Front End

IR files

.obj

Optimizer

icode

Assembler asmsc100

Assembler asmsc100

Assembler asmsc100

Object library files .elb

Linker

Figure 4. StarCore Local Optimization

Introduction to the SC140 Tools 9