C2j-Complier

A compiler that converts C language to Java bytecode or can directly interpret execution

• As a learning project
• Can be interpreted to execute most C or compiled into Java bytecode
• Toy level, with many features not added, and no optimization

Supported

• Support for all basic statements

• Interpreter：supports pointers, arrays, structs, and struct arrays

• Complier: Pointer not supported

How to use

1. Go to releases and download the jar

2. Go to the command line to start

java -jar C2j-Complier.jar -m interpreter -f test.c
java -jar C2j-Complier.jar -m codegen -d true -f test.c

An example

The source file

void swap(int arr[10], int i, int j) {
    int temp;
    temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
}

void quickSort(int a[10], int p, int r) {
    int x;
    int i;
    i = p - 1;
    int j;
    int t;
    int v;
    v = r - 1;
    if (p < r) {
        x = a[r];
        for (j = p; j <= v; j++) {
            if (a[j] <= x) {
                i++;
                swap(a, i, j);
            }
        }
        v = i + 1;
        swap(a, v, r);
        t = v - 1;
        quickSort(a, p, t);
        t = v + 1;
        quickSort(a, t, r);
    }
}


void main () {
    int a[10];
    int i;
    int t;

    printf("Array before quicksort:");
    for(i = 0; i < 10; i++) {
        t = (10 - i);
        a[i] = t;
        printf("value of a[%d] is %d", i, a[i]);
    }

    quickSort(a, 0, 9);

    printf("Array after quicksort:");
    for (i = 0; i < 10; i++) {
        printf("value of a[%d] is %d", i, a[i]);
    }
}

Interpreted

The first run generates lrStateTable.sb under the folder, which is the parse table

Complier

java -jar C2j-Complier.jar -m codegen -f test.c

Generate C2Bytecode.j under the folder,Use a third-party bytecode compiler to generate class files

Part of the generated bytecode:

.class public C2Bytecode
.super java/lang/Object

.method public static main([Ljava/lang/String;)V
	sipush	10
	newarray	int
	astore	0
	sipush	0
	istore	1
	sipush	0
	istore	2
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	ldc	"Array before quicksort:"
	invokevirtual	java/io/PrintStream/print(Ljava/lang/String;)V
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	ldc	"
"
	invokevirtual	java/io/PrintStream/print(Ljava/lang/String;)V
	sipush	0
	istore	1

loop0:
	iload	1
	sipush	10
if_icmpge branch0
	sipush	10
	iload	1
	isub
	istore	2
	aload	0
	iload	1
	iload	2
	iastore
	aload	0
	iload	1
	iaload
	istore	3
	iload	1
	istore	4
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	ldc	"value of a["
	invokevirtual	java/io/PrintStream/print(Ljava/lang/String;)V
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	iload	4
	invokevirtual	java/io/PrintStream/print(I)V
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	ldc	"] is "
	invokevirtual	java/io/PrintStream/print(Ljava/lang/String;)V
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	iload	3
	invokevirtual	java/io/PrintStream/print(I)V
	getstatic	java/lang/System/out Ljava/io/PrintStream;
	ldc	"
"
	invokevirtual	java/io/PrintStream/print(Ljava/lang/String;)V
	iload	1
	sipush	1
	iadd
	istore	1
goto loop0

C language source program test

Code generation does not support Pointers

void quicksort(int A[10], int p, int r) {
    int x;
    int i;
    i = p - 1;
    int j;
    int t;
    int v;
    v = r - 1;
    if (p < r) {
        x = A[r];
        for (j = p; j <= v; j++) {
            if (A[j] <= x) {
                i++;
                t = A[i];
                A[i] = A[j];
                A[j] = t;
            }
        }
        v = i + 1;
        t = A[v];
        A[v] = A[r];
        A[r] = t;
        t = v - 1;
        quicksort(A, p, t);
        t = v + 1;
        quicksort(A, t, r);
    }
}

void main () {
    int a[10];
    int i;
    int t;
    printf("before quick sort:");
    for(i = 0; i < 10; i++) {
        t = (10 - i);
        a[i] = t;
        printf("value of a[%d] is %d", i, a[i]);
    }
    quicksort(a, 0, 9);
    printf("after quick sort:");
    for (i = 0; i < 10; i++) {
        printf("value of a[%d] is %d", i, a[i]);
    }
}

void main() {
    struct s1 {
        int a1;
    };

    struct s2 {
        struct s1 s;
        int a2;
    };

    struct s2 tag;
    tag.s.a1 = 1;
    tag.a2 = 2;
    printf("set filed a1 of struct s1 to value : %d, and a2 of tag to value : %d", tag.s.a1, tag.a2);
}

void main() {
    char *p;
    p = malloc(2);
    *(p+0) = 1;
    *(p+1) = 2;
    printf("p[0] is : %d, p[1] is : %d", *(p+0), *(p+1));
}

void main() {
    struct TAG {
        char c;
        char b[3];
        int p;
    } tag;
    struct TAG* pTag;
    int sz;
    sz = sizeof(tag);
    pTag = malloc(sz + 8);
    pTag[0] = 5;
    pTag[1] = 10;
    pTag[2] = 12;
    printf("c is %d, b[0] is %d, b[2] is %d ", pTag->c, pTag->b[0],  pTag->b[1]);
}

struct Body {
    int a;
    char c;
};

void main() {
    struct Body body;
    body.a = 66;
    printf("The value of a of this structure is %d", body.a);
}

struct Body {
    int a;
    char c;
};

void main() {
    struct Body bodys[5];
    bodys[2].a = 66;
    printf("The value of a of this structure is %d", bodys[2].a);
}

doc

Some notes