Summary

And in Conclusion$\dots$

We spent one chapter covering one figure:

Flow chart for steps for compiling and running a C program.

• The Compiler converts a single high-level language file into a single assembly language file.
• The Assembler removes pseudoinstructions, converts what it can to machine language, creates checklist for the linker (relocation table).
  • These details are stored in an object file.
  • The assembler does 2 passes to resolve addresses in the text segment, handling internal references to position-independent code.
• The Linker combines several .o files and resolves absolute addresses.
  • The linker enables separate compilation, libraries that need not be compiled, and resolves remaining addresses (more details)
• The Loader loads executable into memory and begins execution.

Textbook Readings

P&H 2.12

Exercises

Check your knowledge!

Conceptual Review

Solution

Two: The first finds all the label addresses, and the second resolves forward references while using these label addresses.

Solution

The assembler usually handles relative addressing. The linker handles absolute addressing, resolving the references to memory locations outside.

Solution

• Header: Sizes and positions of the other parts
• Text: The machine code
• Data: Binary representation of any data in the source file
• Relocation Table: Identifies lines of code that need to be “handled” by the Linker (jumps to external labels (e.g. lib files), references to static data)
• Symbol Table: List of file labels and data that can be referenced across files
• Debugging Information: Additional information for debuggers