4.5.2 Position-Independent Code and –xcode

Position-independent code (PIC) can be bound to any address in a program without requiring relocation by the link editor. Such code is inherently sharable between simultaneous processes. Thus, if you are building a dynamic, shared library, you must compile the component routines to be position-independent by using the -xcode compiler option.

In position-independent code, each reference to a global item is compiled as a reference through a pointer into a global offset table. Each function call is compiled in a relative addressing mode through a procedure linkage table. The size of the global offset table is limited to 8 Kbytes on SPARC processors.

Use the compiler flag -xcode=v for specifying the code address space of a binary object. With this flag, 32-, 44-, or 64-bit absolute addresses can be generated, as well as small and large model position-independent code. (-xcode=pic13 is equivalent to the legacy -pic flag, and -xcode=pic32 is equivalent to -PIC.)

The -xcode=pic32 compiler option is similar to -xcode=pic13, but allows the global offset table to span the range of 32–bit addresses. See the f95(1) man page or the Fortran User’s Guide, for details.