Chapter 1. About the MIPSpro Compiler System

The MIPSpro compiler system consists of a set of components that enable you to create new 32-bit and 64-bit executable programs (as well as old 32-bit executables) using languages such as C, C++, and Fortran.

A new 32-bit mode, n32, was introduced with the IRIX 6.1 operating system. This new 32-bit mode has the following features:

The new 32-bit mode (n32) provides better performance than the old 32-bit mode available in IRIX releases prior to 6.1. When you compile with the -n32 option, the chip executes in 64-bit mode and the software restricts addresses to 32 bits. For more information about n32, refer to the MIPSpro N32 ABI Handbook.

In addition, the MIPSpro compiler system:

Table 1-1, summarizes the compiler system components and the task each performs.

Table 1-1. Compiler System Functional Components




Text editor

Write and edit programs

vi, jot , emacs

Compiler driver

Compile, link, and load programs

cc, CC , f77, f90, as

Object file analyzer

Analyze object files

dis, dwarfdump , elfdump, file, nm, size


Analyze program performance

cvperf, prof, sscompare, ssrun


Produce object-file libraries



Link object files


Runtime linker

Link Dynamic Shared Objects at runtime



Debug programs

cvd, dbx

A single program called a compiler driver (such as cc, CC, f77, or f90) invokes the following major components of the compiler system (refer to Figure 1-1)

You can invoke a compiler driver with various options (described in the relevant man page, such as cc(1)) and with one or more source files as arguments. All specified source files are automatically sent to the macro preprocessor. To prevent running the preprocessor, use the -nocpp option on the driver command line.

Your program can take advantage of multiple CPUs (when present) to achieve higher computation rates. The optional parallel analyzers produce parallelized source code from standard source code. For more information about these packages and how to obtain them, contact your dealer or sales representative.

The compiler front end translates the source code into an intermediate tree representation. The compiler back end translates the intermediate code into object code. The language compilers share the same back end, which combines optimization and code generation in one phase. (For more information about optimization, see Chapter 4, “Optimizing Program Performance”).

The linker ld combines several object files into one, performs relocation, and resolves external symbols. The driver automatically runs ld unless you specify the -c option to skip the linking step.

When you compile or link programs, by default the compiler searches specific libraries depending on the compilation mode (shown in Table 1-2). Certain default libraries are automatically linked.

Table 1-2. Compiler Mode and Default Library Search Path




/usr/lib, /lib, and /usr/local/lib


/usr/lib32, /lib32, and /usr/local/lib


/usr/lib64, /lib64, and /usr/local/lib

Compiler drivers and their respective libraries are listed in Table 1-3.

Table 1-3. Compilers and Default Libraries


Default Libraries



f77, f90,,,

To see the various utilities a program passes through during compilation, invoke the appropriate driver with the -show option.

Figure 1-1 shows compilation flow from source file to executable file (a.out).

Figure 1-1. Compiler System Flowchart

Compiler System Flowchart