ECEn 324 Review Topics: Chapter 7

---

• Can you explain what each of the tools invoked by a compiler driver does, including the pre-processor, the compiler proper, the assembler, and the linker? (What kinds of files does each read and write?)
• What are the main tasks that any linker must perform?
• What are the three types of object files?
• ELF relocatable object files:
  • What types of information are stored in an ELF relocatable object file?
  • What sections are included in the file and why? (Why separate each from the others?)
  • What information exists specifically to allow relocation? (What information is contained within a relocation entry and how is relocation handled for PC-relative and absolute addresses? Which sections are affected by relocation?)
  • What kind of symbol information is present?
  • How are variables and functions with the "static" attribute handled differently?
• What are possible outcomes when global symbols are multiply defined?
• How are static libraries organized and how much of each is included by the linker?
• What algorithm is used by the linker to resolve symbols for a list of relocatable object files and archives? (What "baffling link-time errors" can result?)
• What kind of information is present in an ELF executable object file? (What are key differences with relocatable object files?)
• What are the actions taken by a loader? (What additional insight comes from the text's discussion of processes, virtual memory, and memory mapping?)
• What are the differences between static and dynamic linking? (Consider memory layout, actions of the linker, actions of the loader, the use of shared libraries, etc.)
• What functionality is provided to application programs under Linux to load and link shared libraries at run (not load) time?
• Self test: Can you complete all practice problems in Chapter 7?

Updated for 2nd Edition of CS:APP