programming-for-dummies

Choosing a Compiler 87
than other compilers. As a result, it’s possible to compile the same C++ program
under two different C++ compilers and create identically working
programs that consist of different machine language instructions.
The goal of every compiler is to create a program that takes up as little memory
and disk space as possible while running as fast as possible. Usually, compilers
make a trade off. To make a program run faster, the executable file may take
up a large amount of disk space or require a lot of memory. If the compiler
can reduce the size of your program and the amount of memory it needs to
run, it may create a slow program.
Book I
Chapter 4
Programming Tools
To help you tweak your program for the best balance of speed, size, and
memory requirements, many compilers offer optimization settings. By fiddling
with these optimization settings, you can tell the compiler how to
speed up or shrink your program, as shown in Figure 4-1.
Figure 4-1:
Compiler
optimization
settings let
you make
your
program as
small and as
fast as
possible.
One major feature of a compiler’s code generation capabilities involves
speed, which can measure two different features:
✦ Speed can refer to how quickly the compiler works in translating your
source code to machine code.
In the old days, compilers could take hours or days to compile a simple
program. Nowadays, compilers often work in minutes or even seconds.
Shove in a program that consists of 800,000 lines of code, and in less
than a minute, the compiler can create an executable file for you. The
faster the compiler works, the less time you waste running and testing
your program.