Segment Contents

An object file segment consists of one or more sections, though this fact is transparent to the program header. Whether the file segment holds one section or many sections, is also immaterial to program loading. Nonetheless, various data must be present for program execution, dynamic linking, and so on. The following diagrams illustrate segment contents in general terms. The order and membership of sections within a segment can vary.

Text segments contain read-only instructions and data. Data segments contain writable-data and instructions. See Table 7–10 for a list of all special sections.

A PT_DYNAMIC program header element points at the .dynamic section. The .got and .plt sections also hold information related to position-independent code and dynamic linking.

The .plt can reside in a text or a data segment, depending on the processor. See Global Offset Table (Processor-Specific) and Procedure Linkage Table (Processor-Specific) for details.

Sections of type SHT_NOBITS occupy no space in the file, but contribute to the segment's memory image. Normally, these uninitialized data reside at the end of the segment, thereby making p_memsz larger than p_filesz in the associated program header element.