Intermediate Code Generation.pptx

Compiler Design - Intermediate Code Generator
Engineering

1. Intermediate Code Generator Dr.P.Kumaran AP/CSE

2. Intermediate Code Generations An intermediate representation of the final machine language code is produced. This phase bridges the analysis and synthesis phases of translation. Example temp1:= int to real (60) temp2:= id3 * temp1 temp3:= id2 + temp2 id1:= temp3. id1 = id2 + id3 * id4

3. Phases of Compiler

4. Semantic Analysis Position:= initial + rate *60 Example

5. Syntax Directed Definition (SDD) Production + Semantic Rules Syntax Directed Translation (SDT) Production + Semantic Action Semantic Analysis

6. Grammar + Semantic Rules= SDD SDD for Evaluation of Expression E  E+T { E.value = E.value+T.value } E T { E.value = T.value } T T*F { T.value = T.value * F.value } T F { T.value = F.value } F  num { F.value = num.value } Syntax Directed Definition (SDD) Example1

7. 2+3*4 Syntax Directed Definition (SDD) Cont..

8. Example2 Syntax Directed Definition (SDD) Cont.. L  E {L.val=E.val} E  E 1 + T { E.val= E 1 .val+ T.val} E  T {E.val=T.val} T T 1 *F { T.val= T 1 .val* F.val } TF {T.val=F.val} F(E) {F.val=E.val} F digit {F.val= digit.lexval }

9. Syntax Directed Definition (SDD) Cont.. (9+10)

10. SDD  Attribute Types Synthesized Attribute  value defined by its child and itself

11. D  TL {L.inh= T.type } T int { T.type =‘integer’} Treal { T.type =‘real’} L L 1 ,id {L 1 .inh= L.inh } addtype { id.entry , L.inh} L id addtype { id.entry , L.inh} Syntax Directed Definition (SDD) Cont.. Example3

12. real id1,id2,id3 Syntax Directed Definition (SDD) Cont..

13. SDD  Attribute Types Inherited Attribute  value defined by its parent or siblings or itself S- Attributed Definitions: synthesized L- Attributed Definitions: Synthesized and Inherited

14. E E*T {E.val=E.val* T.val } E T {E.val=T.val} T  F-T {T.val=F.val – T.val} T F {T.val=F.val} F 2 {F.val=2} F 4 {F.val=4} Syntax Directed Definition (SDD) Cont.. Example4

15. 4-2-4*2 Syntax Directed Definition (SDD) Cont..

16. Example1 Syntax Directed Translation (SDT) E  E+T { printf(“+”); } 1 E T {} 2 T T*F { printf(“*”); } 3 T F {} 4 F  num { printf(num.val); } 5

17. 2+3*4 (Infix to Postfix conversion) – TDP  top down and left to right Syntax Directed Translation (SDT) Cont..

18. 2+3*4 (Infix to Postfix conversion) – BUP Syntax Directed Translation (SDT) Cont..

19. Example2 Syntax Directed Translation (SDT) Cont.. S  xxW {printf(1);} S  y {printf(2);} W  Sz {printf(3);}

20. xxxxyzz Syntax Directed Translation (SDT) Cont..

21. Graphical IR Graph Control-Flow Graph Dependence Graph Call Graph Tree Parse Tree Abstract syntax tree Directed acyclic graph Linear IR 3-Address Code Stack Machine Code Linear Code Hybrid IR Intermediate Code Generator

22. Graphical IR - Graph Control-flow graph

23. Graphical IR- Graph Dependence Graph

24. Graphical IR- Graph Call Graph

25. Graphical IR - Tree Parse Tree

26. Graphical IR - Tree Abstract Syntax Trees a ×2+ a× 2 × b

27. Graphical IR - Tree Directed Acyclic Graphs a ×2+ a× 2 × b

28. ICG- Graphical Representation Common Sub Expression Elimination a= b*-c + b*-c

29. Linear IR 3 Address Code

30. Linear IR Stack Machine Code

31. 3- Address Code x:=y op z x,y, and z names, constants, or temporaries op  Operator (arithmetic or logical ) Example: x+y *z t1:=y*z t2:=x+t1

32. 3- Address Code a= b*-c + b*-c

33. Assignment Statement : x:=y op z op  Arithmetic or logical operator Assignment Statement : x:= op y op Unary Operator Copy Statement : x:=y Unconditional Jump : goto L Conditional Jump : if x relop y goto L Procedure call : p(x1,x2,x3,…, xn ) Param x1 Param x2 ………….. Param xn Call p,n Type of 3- Address Statements

34. In compiler the 3 address code is field of records Quadruples Triples Indirect Triples 3- Address Code

35. 3- Address Code Indirect Triples

36. Examples

37. Example 1

38. Example 2

39. Example 3

40. IMG-DECLARATIONS

41. D  TL {L.inh= T.type } T int { T.type =‘integer’} Treal { T.type =‘real’} L L 1 ,id {L 1 .inh= L.inh } addtype { id.entry , L.inh} L id addtype { id.entry , L.inh} IMG-Declarations

42. real id1,id2,id3 IMG-Declarations

43. mktable (previous) enter( table,name,type,offset ) addwidth ( table,width ) enterproc ( table,name,newtable ) lookup( table,name ) IMG-Declarations

44. IMG-Declarations

45. IMG-Declarations

46. IMG-Declarations

47. IMG-Declarations

48. Example 4

49. Example 5

50. Example 6

51. Example 7

52. Example 8

53. Example 9