GCC, GNU compiler collection
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GCC is a widely used open source compiler system developed by the GNU Project. It compiles C, C++, Java, Fortran and other languages. GCC has undergone major changes to its structure since 2005, including the addition of GENERIC and GIMPLE intermediate representations between the front end and back end. The front end parses source code into ASTs, then GIMPLE trees are optimized through many passes in the middle end before being converted to RTL for the back end code generation.
GCC, GNU compiler collection
- 1. GCC : GNU compilers collection Alberto Bustamante Reyes ( www.albertobustamante.com ) Author:
- 2. Brief introduction Compiler system developed by GNU Project
- 3. Distributed by FSF under GPL License
- 4. Written in C / C++
- 5. Default compiler for Unix and Mac OS X
- 6. Also ported to Windows (MinGW)
- 7. Brief introduction Originally developed for C language
- 8. Several front-ends added to support different languages: C / C++ (gcc / g++)
- 9. Java (gcj)
- 10. Objective-C / Objective-C++ (gobjc / gobjc++ )
- 12. Structure Generic compiler: Front end
- 13. Back end GCC compiler: Front end
- 14. Middle end
- 15. Back end
- 16. Structure GCC Compiler (before 2005) Source code AST RTL RTL Object code FRONT END BACK END
- 17. Structure GCC Compiler (before 2005) Source code AST RTL RTL Object code FRONT END BACK END
- 18. Structure GCC Compiler (before 2005) Source code AST RTL RTL Object code FRONT END BACK END SSA Tree project: OPTIMIZATIONS
- 19. Structure GCC Compiler (after 2005) Source code AST GENERIC GIMPLE RTL FRONT END
- 20. Structure GCC Compiler (after 2005) Source code AST GENERIC GIMPLE RTL FRONT END Language dependent Language independent
- 21. Structure GCC Compiler (after 2005) Source code AST GENERIC GIMPLE RTL FRONT END Language dependent Language independent MIDDLE END
- 22. Structure: GENERIC & GIMPLE Why two kinds of trees? GIMPLE is a simplified subset of GENERIC GIMPLE GENERIC
- 23. Structure: GENERIC & GIMPLE GENERIC -> (Gimplifier) -> GIMPLE GIMPLIFIER if (foo ( a + b, c)) c = b ++ / a end if return c t1 = a +b t2 = foo (t1, c) If (t2 != 0 ) <L1, L2> L1: t3 = b b = b + 1 c = t3 / a goto L3 L2: L3: return c
- 24. Structure: GENERIC & GIMPLE Developed by SSA Tree Project
- 25. SSA Developed by IBM in 1980
- 27. Example: y := 1 y := 2 x := y y1 := 1 y2 := 2 x1 := y2
- 28. Structure: Middle end GIMPLE Tree SSA Optimizer RTL
- 29. Structure:Middle end SSA Tree Optimization Dead code elimination y := 1 y := 2 x := y y1 := 1 y2 := 2 x1 := y2
- 30. Structure:Middle end SSA Tree Optimization Dead code elimination
- 31. Partial redundancy elimination if (some_condition) { // some code y = x + 4; }else { // other code } z = x + 4; if (some_condition) { // some code y = x + 4; t = y; }else { // other code t = x + 4; } z = t;
- 32. Structure:Middle end SSA Tree Optimization Dead code elimination
- 34. Global value numbering w := 3 x := 3 y := x + 4 z := w + 4 w := 3 x := w y := w + 4 z := y
- 35. Structure:Middle end SSA Tree Optimization Dead code elimination
- 38. Sparse conditional constant propagation
- 39. Structure:Middle end SSA Tree Optimization Dead code elimination
- 42. Sparse conditional constant propagation
- 43. Scalar replacement of aggregates
- 44. Structure: RTL Output of the Middle End
- 46. Looks like Lisp S-expressions: (set:SI (reg:SI 140) (plus:SI (reg:SI 138) (reg:SI 139)))
- 47. Structure: summary Source code AST GENERIC GIMPLE Tree SSA Optimizer RTL Optimized RTL Object code FRONT END MIDDLE END BACK END
- 48. Advantages of using GCC Reliable Suppported by GNU & FSF
- 49. Active and noumerous developer team
- 50. One of the most popular compilers
- 51. Lots of test cases (users) Several front ends
- 52. Free!!
- 53. More information available at… GCC : http://gcc.gnu.org
- 54. GCC Wiki : http://gcc.gnu.org/wiki
- 55. SSA Tree Project: http://gcc.gnu.org/projects/tree-ssa/
- 56. GNU : http://www.gnu.org
- 57. Free Software Foundation : http://www.fsf.org
- 59. The End Thanks for watching
- 60. GCC : GNU compilers collection Alberto Bustamante Reyes ( www.albertobustamante.com ) Author: