Decaf Compiler

File Structure

• src
  • Makeile :
    • use "make" to run
  • parser.ypp :
    • Reading the code from a file. Creating nodes of AST tree
  • scanne.l :
    • Return tokens one by one to the parser file
  • ast.h :
    • contains all the class and method declarations.
    • Has code for traversing the AST tree using vsitor design pattern
    • All semantic erros are handled while creating the AST tree
  • ast.cpp
    • All methods are written here.
    • generate code functions were used for creating LLVM-IR
• test-programs
  • 17 dcf programs, for some of them are outputs are in sample outputs section

How to run

- bison -d parser.ypp
- bison -d parser.ypp
- g++ -std=c++11 -o parser parser.tab.cpp lex.yy.c ast.cpp -ll -g -ldl -lfl `llvm-config-6.0 --cppflags --libs --libfiles core --ldflags --system-libs`
- ./parser inputfile
- lli-6.0 outfile

Sample output

arraysum.dcf

rallaakhil@rallaakhil:~/compilers/project/phase-2$ make
bison -d parser.ypp
flex scanner.l
# g++ -std=c++11 -o parser parser.tab.cpp lex.yy.c ast.cpp -ll
g++ -std=c++11 -o parser parser.tab.cpp lex.yy.c ast.cpp -ll -g -ldl -lfl `llvm-config-6.0 --cppflags --libs --libfiles core --ldflags --system-libs`
rallaakhil@rallaakhil:~/compilers/project/phase-2$ ./parser test-programs/arraysum.dcf 
Starting
Parsing Over
Started dfs
Done dfs
Started generating LLVM-IR
LLVM-IR generated
rallaakhil@rallaakhil:~/compilers/project/phase-2$ lli-6.0 outfile
The sum of given vector is : 45

Description

The grammar writtem does not have any shift/reduce or reduce/reduce conflicts. The main code is in parser.ypp file. In this main function we first do yyparse(). In yyparse() the creation of AST, checking semantic errors. After that, dfs is done whose code is written in ast.h. Dfs is done using the visitor design pattern. Then after, LLVM-IR code is generated using generate code methods written for various classes. The LLVM-IR output is written in outputfile. We can lli interpreter to run the outputfile. Run-time checking is done, as we haven't done interpreter code evaluation.

Output for some more programs

bubble.dcf

rallaakhil@rallaakhil:~/compilers/project/phase-2$ ./parser test-programs/bubble.dcf 
Starting
Parsing Over
Started dfs
Done dfs
Started generating LLVM-IR
LLVM-IR generated
rallaakhil@rallaakhil:~/compilers/project/phase-2$ lli-6.0 outfile
The final sorted order  is : 
1 2 3 4 5 6 7 8 9 10

quick_sort.dcf

rallaakhil@rallaakhil:~/compilers/project/phase-2$ ./parser test-programs/quick_sort.dcf 
Starting
Parsing Over
Started dfs
Done dfs
Started generating LLVM-IR
LLVM-IR generated
rallaakhil@rallaakhil:~/compilers/project/phase-2$ lli-6.0 outfile
sorted array : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 

mergesort.dcf

rallaakhil@rallaakhil:~/compilers/project/phase-2$ ./parser test-programs/merge_sort.dcf 
Starting
Parsing Over
Started dfs
Done dfs
Started generating LLVM-IR
LLVM-IR generated
rallaakhil@rallaakhil:~/compilers/project/phase-2$ lli-6.0 outfile
sorted array : 1 2 3 4 5 6 7 8 9 10

gcd.dcf

rallaakhil@rallaakhil:~/compilers/project/phase-2$ ./parser test-programs/gcd.dcf 
Starting
Parsing Over
Started dfs
Done dfs
Started generating LLVM-IR
LLVM-IR generated
rallaakhil@rallaakhil:~/compilers/project/phase-2$ lli-6.0 outfile
gcd is 6