George Gribkov presented on how to introduce static analysis to make programmers' and QA engineers' lives easier. Static analysis automatically checks code for bugs without executing it. While initial attempts to analyze Unreal Engine 4 failed, monitoring compiler calls directly succeeded in finding over 1800 warnings. Epic Games now uses continuous static analysis to receive early warnings. The best practices are to start analysis early and regularly in development and CI/CD pipelines, and to gradually fix old warnings using suppression files to ratchet down reported issues over time. Static and dynamic analysis complement each other to thoroughly check for errors.

1. Make Your and Other Programmer’s Life Easier
with Static Analysis
(Unreal Engine 4)
Speaker:
George Gribkov

2. George Gribkov
C++ programmer, one of the static
analyzer developers in PVS-Studio
Developing analyzer’s core and new
rules. Providing user support.
Publishes articles on Habr and
speaks at conferences.
gribkov@viva64.com
About the Speaker
2

3. 1. What is static analysis and what is it for?
2. How does static analysis work? (Unreal Engine 4)
3. How to introduce static analysis in your project: best
practices
Content
3

4. What Is Static Analysis and What Is It for?
4

5. Challenges
5
Programmers

6. Challenges
6
Programmers QA Engineers

7. Challenges
7
Programmers QA Engineers

8. Challenges
8
Programmers QA Engineers

9. Challenges
9
Programmers QA Engineers

10. Challenges
10
Programmers QA Engineers

11. Challenges
11
Programmers QA Engineers

12. Challenges
12
Programmers QA Engineers

13. Challenges
13
Programmers QA Engineers

14. Challenges
14
Programmers QA Engineers

15. Challenges
15
Programmers QA Engineers

16. Challenges
16
Programmers QA Engineers

17. Challenges
17
Programmers QA Engineers

18. Challenges
18
Programmers QA Engineers

19. Challenges
19
Programmers QA Engineers

20. Challenges
20
Programmers QA Engineers

21.  Programmers miss bugs
 QA Engineers spend time to find them
 Programmers spend time to fix them
 Cost to fix bugs rises rapidly
Challenges
21

22. Challenges
22

23. Challenges
23

24. But sometimes tests
skip errors…
24

25. Ariane
4
25

26. Ariane 4
26
113 successful
launches
Ariane
4

27. Ariane
5
27

28. 28
Ariane
5
370 000 000 $ blown
up!

29.  Integer overflow caused the explosion
 Rocket had four satellites
 Losses amounted to $ 370 000 000
Example of Very Expensive Error
29

30.  Unit testing
 Integration testing
 System testing
 …
Ways to Find Error
30

31.  Unit testing
 Integration testing
 System testing
 …
 Dynamic analysis
 Static analysis
Ways to Find Error
31

32.  Static analysis tools: check code when it’s not
executed
 Dynamic analysis tools: check code when it’s
being executed
Automated Code Analysis Tools
32
 Both approaches complement each other very
well

33.  Static analysis tools: check code when it’s not
executed
 Dynamic analysis tools: check code when it’s
being executed
Automated Code Analysis Tools
33
 Both approaches complement each other very
well

34. Static Analysis Automatically
Searches for Bugs
34

35. 35

36.  Covers the entire code
 Works fast
 Is convenient for all sizes of projects
 Saves programmer’s time
 Saves QA Engineers’ time
Static Analysis Pros
36

37. Modern Static Analysis Tools
37
• PVS-Studio
• ReSharper
• Coverity
• SonarQube
• Klocwork
• Clang Static Analyzer
• IntelliJ IDEA
• ...
• A full list of static analysis
tools:

38. How It Works: Static Analysis in UE 4
38

39. How It Started
39

40.  My boss found errors in UE 4
and wrote an article
 The developers of Epic Games
liked the article a lot
 They wanted to fix more errors
and entrusted it to us
How It Started
40

41. The First Check
(or How We Screwed Up)
41

42.  The most convenient way: check the project via
Visual Studio
 It’s great that UE has a set of scripts for .vcxproj-
files
The First Check
42

43. 1.We generate project files
2.We build the project
3.We start the analysis via Visual
Studio
4.???????
5.
The First Analysis Attempt
43

44. 1.Generate project files
2.Build the project
3.Start the analysis via Visual
Studio
4.???????
5. EPIC GAMES FAIL
First Check
44

45.  Generated project files are just wrappers
 These wrappers call the Unreal Build Tool
 Unreal Build Tool calls cl.exe (or clang for Linux
builds)
Unreal Engine Build System
45

46.  Generated project files are just wrappers
 These wrappers call the Unreal Build Tool
 Unreal Build Tool calls cl.exe (or clang for Linux
builds)
 The analyzer cannot collect the parameters
required for compilation because of all these
layers
Unreal Engine Build System
46

47. The Second Check
(or How We Did Everything Right)
47

48.  What if we try to find compiler calls directly?
The Second Check
48

49.  What if we try to find compiler calls directly?
 We’re lucky to have a special utility to monitor
compilation
The Second Check
49

50. 1.Start the compilation monitoring
utility before building the project
2.The utility builds all the necessary
data
3.Right after build run the analysis
4.???????
5.
The Second Analysis Attempt
50

51. The Second Analysis Attempt
51
1.Start the compilation monitoring
utility before building the project
2.The utility builds all the necessary
data
3.Right after build run the analysis
4.???????
5. EPIC WIN!!!

52. Analysis Results
52

53. Analysis Results
 1192 top level warnings
(Level 1)
 629 second level warnings
(Level 2)
 1821 warnings in total
(without Level 3)
53

54. 54

55. Hahaha, classic
 Notepad++ – 3 810 warnings
55

56. Hahaha, classic
 WinMerge – 6 830 warnings
56

57. Hahaha, classic
 Media Player Classic Home Cinema – 24 872 warnings!
57

58. How We Fixed Bugs
58

59.  At night we built the final version of UE 4
 We analyzed each build
 In the morning, we got a new report with errors found
 What’s more, we could check the build right away
How We Fixed Bugs
59

60. Our Progress
60
60

61. The Number of Warnings
61
0
5
10
15
20
25
1 2 3 4 5
Warnings
0
5
10
15
20
25
1 2 3 4 5
Warnings
 Expectation  Reality

62. After we fixed errors, we
found four new warnings
The Icing on The Cake
62

63.  The developers of Epic Games were pleased
 They started using a continuous static code analysis, as we
did
 Now they receive warnings about errors in time
 As for us… we wrote another article :)
Results
63

64. Best Way to Introduce Static Analysis in
Your Project
64

65.  Run the analysis in the early
stages
 Run the analysis regularly
Two Main Approaches
65

66. Why Static Analysis is Useful
66

67. Why Static Analysis is Useful
67
Static Analysis

68. Why Static Analysis is Useful
68
Static Analysis
You

69.  May be used locally on developers’ computer (plugins for
IDEs, compilation monitoring system)
Introducing Static Analysis
69

70.  May be used in Continuous Integration Systems (command-
line utilities, CI-system plugins, monitoring systems)
Introducing Static Analysis
70

71. Continuous Analysis
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72. Continuous Analysis
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73. Continuous Analysis
73

74. Continuous Analysis
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75. Continuous Analysis
75

76. Continuous Analysis
76

77. Continuous Analysis
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78. Continuous Analysis
78

79. Challenges
79
Programmers QA Engineers

80. Challenges
80
Programmers QA Engineers

81. Challenges
81
Programmers QA Engineers

82. Fix Old Warnings Gradually
82

83. Suppress files introduce the "mass suppression of
analyzer messages" mechanism.
Suppress files
83

84.  Hide old errors – work as usual
 Have only new warnings from now on
 Gain analysis benefits RIGHT AWAY
 Don’t forget about hidden errors! Get back to them and
gradually fix.
Suppress files allow you to
84

85.  A very convenient method is a “ratchet mechanism”
 Suppress file commits to the version control system
 Changes are allowed only if they don’t increase warnings total
number
What to Do With Suppress files
85

86. Ratchet Mechanism
86

87. Ratchet Mechanism
87

88.  Ivan Ponomaryov — Continuous Static Code
Analysis​
Talk on Related Topic
88

89. Ratchet Mechanism
89

90.  NO
 The best approach: static + dynamic analysis
Should I Use Static Analysis Only?
90

91. Conclusion
91

92. Conclusion
92
Help programmers find bugs and make
your life easier!

93. Gift from PVS-Studio
93
Free license
for open-source projects:
One-month PVS-Studio free
trial​:
www.pvs-studio.com/pvs-free-
opensource
www.pvs-studio.com/download-
sqadays

94. END
Q&A94