Linking

Question 1

The process of collecting and combining various pieces of code and data into a single file that can be loaded (coped) into memory and executed

Answer 1

Linking

Question 2

The process of adjusting addresses in object modules when modules are linked with other modules to create and executable

Answer 2

Relocation

Question 3

When can linking be dome

Answer 3

Compile time
Load time
Run time

Question 4

Programs are translated and linked using a ______ ______

Answer 4

Compile driver

Question 5

First reason why linkers are useful

Answer 5

Modularity: program can be written as a collection of smaller source files rather than one monolithic mass
Can build libraries of common functions

Question 6

What do linkers do?

Answer 6

Step 1: symbol resolution

Question 7

Symbol definitions are stored in object file in a _____ ____

Answer 7

Symbol table

Question 8

Symbol table is an ______ of ____

Answer 8

Array, structs

Question 9

What is the next step of linking

Answer 9

Relocation

Question 10

Relocation merges separate code and data sections into _____ sections

Answer 10

Single

Question 11

Contains code and data in a form that can be combined with other relocatable object files to form executable object file

Answer 11

Relocatable object file

Question 12

Contains code and data in a form that can be copied directly into memory and then executed

Answer 12

Executable object file

Question 13

Special type of relocatable object file that can be loaded into memory and linked dynamically either load time or run time

Answer 13

Shared object file

Question 14

ELF

Answer 14

Executable and Linkable Format

Question 15

Word size, byte ordering, file type, machine type, etc

Answer 15

Elf header

Question 16

Page size, virtual address memory segments, segments sizes

Answer 16

Segments header table

Question 17

Code

Answer 17

.text section

Question 18

Read only data: jump tables, ….

Answer 18

.rodata section

Question 19

Unitialized global variables

Answer 19

.bss section

Question 20

Symbols defined by module m that can be referenced by other modules

Answer 20

File cope (global) symbols

Question 21

Fil;e scope symbols that are referenced by module m buy defined by some other module

Answer 21

External symbols

Question 22

Symbols that are defined and referenced exclusively my module m

Answer 22

Local symbols
Local linker symbols are not block scope variables

Question 23

Local non-static c-variables:

Answer 23

Stored on the stack

Question 24

Local static C variables:

Answer 24

Stored in either .bss or .data

Question 25

Procedure/functions and initializes file scope variables

Answer 25

Strong

Question 26

Uninitialized file scope variables

Answer 26

Weak

Question 27

Rule 1: Mutiple strong symbols are not allowed. Each items can be defined only once, otherwise: ________

Answer 27

Linker error

Question 28

Rule 2: Given a strong symbol and multiple weak symbols, choose the _____ symbol. References to _____ symbol resolve to ____ symbol.

Answer 28

Strong. Weak/strong

Question 29

Rule 3: If there are multiple weak symbols, pick and _____ one

Answer 29

Arbitrary

Question 30

Use ____ if you reference an external global variable.

Answer 30

Extern

Question 31

In _____ ______, all the libraries and object files that a program needs a bundled directly into the executable at compile time. The resulting executable contains all the code is needs to run, including external library functions, and desn’t require additional dependencies at run time

Answer 31

Static linking

Question 32

Disadvantage of static libraries

Answer 32

1. Duplication in the stored executables Duplication in the running executables 3. Minor bug fixes of system libraries require each application to explicitly re link

Question 33

In _____ ______, the linker does not include the code for external libraries directly into the exectuable. Instead, it references external shared libraries, which are linked at run time. WHen the program is executed, the operating system loads the shared libraries into memory and resolves external function calls.

Answer 33

Dynamic linking

Question 34

A ____ ____ _____ is a compiled object file that contains functions and data that can be used my multiple program simultaneously at _______

Answer 34

Shared object file, runtime