Chapter 7.5, Problem 7.1PP

Program Plan Intro

Sections in relocatable object files:

There are many sections in a relocatable object file. They are given below:

• “.text”:
  • It is the machine code of the compiled program.
• “.rodata”:
  • This section is used to read only the data in the format such as
    • Strings in “printf” statements.
    • Jump tables for switch statements.
• “.data”:
  • This section is used in the initialized “C” variables of global variable and static “C” variables.
  • Local “C” variables are initialized at execution time on the stack.
    • It does not show in either the “.data” or “.bss” sections.
• “.bss”:
  • It is used in the uninitialized global and static “C” variables, along with any global or static variables that are assigned to zero.
• “.symtab”:
  • It is a symbol table.
  • It contains the information about functions and global variables that are defined and referenced in the program.
• “.rel.text”:
  • This section contains a list of locations in the “.text” section.
    • It will require to be changed once the linker merges this object file with others.
• “.rel.data”:
  • This section contains relocation information for any global variables that are referenced or defined by the module.
• “.debug”:
  • It is a symbol table for debugging
  • It contains entries for following
    • Definition of Local variables, global variables and typedefs variables and original “C” source file.
• “.line”:
  • It is a mapping between line numbers in the given program
    • That is in original “C” source program and machine code instructions in the “.text” section.
• “.strtab”:
  • It is a string table.
    • It contains symbol tables in the “.symtab” and “.debug” sections.
    • It is the table for section names in the section headers.