The document discusses modern C++ compilers and what every C++ programmer should know about them. It covers compiler architecture, inputs and targets, the C++ standard versus compiler realities, undefined behavior, optimizations, outsmarting compilers, the compiler ecosystem, and tools for further optimization like sanitizers, clang tools, Templight, and Stoke.

1. WHAT EVERY C++ PROGRAMMER SHOULD
KNOW ABOUT MODERN COMPILERS
SŁAWOMIR ZBOROWSKI
ACCU 2016, BRISTOL, UK

2. SŁAWEK ZBOROWSKI
WROCŁAW, POLAND

3. OUTLINE
overview
architecture, inputs, targets
standard, compilers and reality
undefined behavior
optimizations
outsmarting compiler
ecosystem
tooling, further optimizations

4. OUTLINE
overview
architecture, inputs, targets
standard, compilers and reality
undefined behavior
optimizations
outsmarting compiler
ecosystem
tooling, further optimizations

13. h t t p : / / l e a n i n g t e c h . c o m / c h e e r p /

14. ARCHITECTURE OVERVIEW

15. h t t p s : / / d e v h u m o r . c o m / c o n t e n t / u p l o a d s / / i m a g e s / O c t o b e r 2 0 1 5 / F r o n t - e n d - x - B a c k - e n d . j p g

16. FLAGS
Newbie -o
Junior -c, -Wl,-shared, -Wl,-static, …
Average -Wall, -Wextra, -Werror, -O2, …
Expert -finline-limit, -ftemplate-depth, …
Ninja -B, -nostdlib, …

18. OUTLINE
overview
architecture, inputs, targets
standard, compilers and reality
undefined behavior
optimizations
outsmarting compiler
ecosystem
tooling, further optimizations

20. h t t p : / / c o m m u n i t y . f a n s s h a r e . c o m / p i c 1 0 8 / w / t r a d u c i a n i s m / 1 2 0 0 / 1 7 5 2 _ c a u t i o n _ t h i s _ i s _ s p a r t a _ j e x . j p g

23. h t t p : / / f a c s t a f f . c b u . e d u / s e i s e n / C a d F a 0 9 1 3 _ f i l e s / i m a g e 0 3 2 . j p g

24. UNDEFINED
BEHAVIOR
SANITIZER

25. h t t p s : / / w w w . y o u t u b e . c o m / w a t c h ? v = H f - z n K i V w y k

26. OUTLINE
overview
architecture, inputs, targets
standard, compilers and reality
undefined behavior
optimizations
outsmarting compiler
ecosystem
tooling, further optimizations

27. OPTIMIZATIONS

28. OUTSMARTING COMPILER
1 auto tmp = a;
2 a = b;
3 b = tmp;
1 a ^= b;
2 b ^= a;
3 a ^= b;
h t t p s : / / w w w . y o u t u b e . c o m / w a t c h ? v = b S 5 P _ L A q i V g

30. COMPILER'S KNOWLEDGE
CPU CACHES
CPU EXTENSIONS
CPU PERFORMANCE BUGS
INSTRUCTION SIZES (IN BINARY)
…

31. OUTLINE
overview
architecture, inputs, targets
standard, compilers and reality
undefined behavior
optimizations
outsmarting compiler
ecosystem
tooling, further optimizations

32. INSTRUMENTALIZATION
ADDRESS SANITIZER
MEMORY SANITIZER
CONTROL FLOW SANITIZER
THREAD SANITIZER
EFFICIENCY SANITIZER
…
h t t p s : / / b o u r n e t o c o d e . c o m / p r o j e c t s / G C S E _ C o m p u t i n g _ F u n d a m e n t a l s / p a g e s / i m g / R A M . j p g
h t t p : / / c r e a t e . p r o / b l o g / w p - c o n t e n t / u p l o a d s / 2 0 1 4 / 1 2 / M a c - P r o - M u l t i - C o r e - P r o c e s s o r - 3 -
e 1 4 1 8 6 5 8 6 8 9 8 7 8 . j p g

33. CLANG TOOLS
CLANG-FORMAT
CLANG-TIDY
CLANG-COMPLETE
CLANG-ANALYZER
…
h t t p s : / / u p l o a d . w i k i m e d i a . o r g / w i k i p e d i a / e n / 4 / 4 c / L L V M _ L o g o . s v g

34. TEMPLIGHT / TEMPLATOR
h t t p s : / / g i t h u b . c o m / m i k a e l - s - p e r s s o n / t e m p l i g h t - t o o l s

35. SYNTH

36. STOKE
Stochastic optimizer (x86_64)

37. THANKS!!