This my final project of Compilers Principles in XMU. It's an Intermediate Representation Code Generator implemented by Flex and Bison.
We call the following language as the Dragon Language, as it's proposed in the appendix A of the Dragon Book. The syntax is:
program -> block
block -> {decls stmts}
decls -> decls decl | ε
decl -> type id ;
type -> basic
stmts -> stmts stmt | stmt
stmt -> id = expr ;
| if ( bool ) stmt
| if (bool) stmt else stmt
| while ( bool ) stmt
| do stmt while ( bool ) ;
| block
bool -> bool || join | join
join -> join && equality | equality
equality -> equality == rel | equality != rel | rel
rel -> expr < expr | expr <= expr | expr >= expr | expr > expr | expr
expr -> expr + term | expr - term | term
term -> term * unary | term / unary | unary
unary -> ! unary | - unary | factor
factor -> ( expr ) | id | num
It can be executed normally if
- Operating System: Ubuntu 16.04 LTS
- Flex 2.6.0
- Bison 3.0.4
- Gcc 5.4.0
- GNU bash 4.3
First, generate the scanner lex.yy.c.
flex scanner.l
Then, generate the parser parser.tab.c and parser.tab.h.
bison -d parser.y
Next, get the executable file compiler.o.
gcc parser.tab.c lex.yy.c compiler.c main.c -o compiler.o
Finally, you can execute compiler.o to get the IR code.
./compiler.o
Enter thr file names of source file *.drg and object file *.txt, then the IR code generated will be stored in *.txt. For example, you can try:
$ ./compiler.o
请输入要编译的源程序文件名：input1.drg
请输入要存放中间代码的文件名：gencode1.txt
I write a shell file called run.sh to finish all the steps above. You can type ./run.sh in the terminal. Please check the names of source file and object file before your execution.