intermediate code generator

The intermediate code generator (Intermediate Code Generator) is an important part of the compiler, which is responsible for converting the source code into an intermediate representation for subsequent operations such as optimization and code generation.

Intermediate code usually adopts a form similar to assembly language, including basic blocks, three-address codes, control flow statements, and so on. Through the intermediate code generator, the source code can be converted into an intermediate code representation for subsequent operations such as optimization and code generation.

For example, suppose you have the following source code:

int main() {
    int a = 10;
    if (a > 5) {
        a = a - 5;
    }
    return a;
}

Using the intermediate code generator to convert the program, the following intermediate code can be obtained:

(1) a = 10
(2) if a > 5 goto 3
(3) a = a - 5
(4) return a

Among them, each row represents a basic block, including three address codes and control flow statements. Through the intermediate code generator, the source code can be converted into an intermediate representation for subsequent operations such as optimization and code generation.

For example:

Assume the following C language program:

int main() {
    int a = 10;
    float b = 3.14;
    if (a > b) {
        printf("a is greater than b\n");
    } else {
        printf("a is less than or equal to b\n");
    }
    return 0;
}

Using the intermediate code generator to convert the program, the following intermediate code can be obtained:

(1) a = 10
(2) b = 3.14
(3) t1 = (float) a
(4) if t1 > b goto 6
(5) goto 7
(6) printf("a is greater than b\n")
(7) printf("a is less than or equal to b\n")
(8) return 0

Among them, (3) means converting variable a to float type for comparison with variable b. (4) means to make a conditional judgment, if t1 (that is, a) is greater than b, then jump to (6); otherwise, jump to (7). (6) and (7) represent the codes of the two branches respectively. Finally, (8) means that the return value is 0.

Through the intermediate code generator, the source code can be converted into an intermediate representation for subsequent operations such as optimization and code generation. In the intermediate code generator, optimization operations such as constant folding, common subexpression elimination, and dead code elimination can be performed to generate more efficient object code.