source: src/tests/dtor-early-exit.c @ 7fe4cc3e

#include <fstream>
#include <stdlib>
extern "C" {
#define false ((int)0)  // until stdbool.h works
#define assert(cond) if (! (cond)) { sout | "Assertion failed: (" | #cond | ") at " __FILE__ | ":" | __LINE__ | endl; abort(); }
}

struct A {
        char * name;
        int * x;
};

// don't want these called
void ?{}(A * a) { assert( false ); }
void ?{}(A * a, char * name) { a->name = name; sout | "construct " | name | endl; a->x = malloc(); }
void ?{}(A * a, char * name, int * ptr) { assert( false ); }

A ?=?(A * a, A a) {  sout | "assign " | a->name | " " | a.name; return a; }
void ?{}(A * a, A a) { sout | "copy construct " | a.name | endl; a->x = malloc(); }
void ^?{}(A * a) { sout | "destruct " | a->name | endl; free(a->x); }

// test returns
void f(int i) {
        sout | "f i=" | i | endl;
        A x = { "x" };  // construct x
        {
                A y = { "y" }; // construct y
                {
                        A z = { "z" }; // construct z
                        {
                                if (i == 0) return; // destruct x, y, z
                        }
                        if (i == 1) return; // destruct x, y, z
                        // destruct z
                }
                if (i == 2) return; // destruct x, y
                // destruct y
        }
        return; // destruct x
}

// test loops, switch, etc.
void g() {
        for (int i = 0; i < 10; i++) {
                sout | "g for i=" | i | endl;
                A x = { "x" };
                // construct x
                // destruct x
        }
        sout | endl;
        {
                int i = 0;
                while (i < 10) {
                        sout | "g while i=" | i | endl;
                        A x = { "x" };
                        // construct x
                        i++;
                        // destruct x
                }
        }
        sout | endl;
        for (int i = 0; i < 10; i++) {
                switch(10) {
                        case 0:
                        case 5:
                        case 10: {
                                A y = { "y" };
                                sout | "g switch i=" | i | endl;
                                // construct y
                                break; // destruct y
                        }
                        default: {
                                sout | "g switch i=" | i | endl;
                                A x = { "x" };
                                // construct x
                                break; // destruct x
                        }
                }
        }
        sout | endl;
        for (int k = 0; k < 2; k++) {
                sout | "g for k=" | k | endl;
                L1: for (int i = 0; i < 10; i++) {
                        sout | "g for i=" | i | endl;

                        A x = { "x" };
                        if (i == 2) {
                                sout | "continue L1" | endl;
                                continue;  // destruct x
                        } else if (i == 3) {
                                sout | "break L1" | endl;
                                break;  // destruct x
                        }

                        L2: for (int j = 0; j < 10; j++) {
                                sout | "g for j=" | j | endl;
                                A y = { "y" };
                                if (j == 0) {
                                        sout | "continue L2" | endl;
                                        continue; // destruct y - missing because object that needs to be destructed is not a part of this block, it's a part of the for's block
                                } else if (j == 1) {
                                        sout | "break L2" | endl;
                                        break;  // destruct y
                                } else if (i == 1) {
                                        sout | "continue L1" | endl;
                                        continue L1; // destruct x,y - note: continue takes you to destructors for block, so only generate destructor for y
                                } else if (k == 1) {
                                        sout | "break L1" | endl;
                                        break L1;  // destruct x,y
                                }
                        }
                }
        }
}

// test goto
void h() {
        int i = 0;
        // for each goto G with target label L:
        // * find all constructed variables alive at G (set S_G)
        // * find all constructed variables alive at L (set S_L)
        // * if S_L-S_G is non-empty, error
        // * emit destructors for all variables in S_G-S_L
        sout | "h" | endl;
        {
                L0: ;
#ifdef ERR1
                        goto L1; // this is an error in g++ because it skips initialization of y
#endif
                        A y = { "y" };
                        // S_L1 = { y }
                L1: sout | "L1" | endl;
                        A x = { "x" };
                        // S_L2 = { y, x }
                L2: sout | "L2" | endl;
                        if (i == 0) {
                                ++i;
                                sout | "goto L1" | endl;
                                // S_G = { y, x }
                                goto L1;  // jump back, destruct b/c before x definition
                                // S_L-S_G = {} => no error
                                // S_G-S_L = { x } => destruct x
                        } else if (i == 1) {
                                ++i;
                                sout | "goto L2" | endl;
                                // S_G = { y, x }
                                goto L2;  // jump back, do not destruct
                                // S_L-S_G = {}
                                // S_G-S_L = {} => destruct nothing
                        } else if (i == 2) {
                                ++i;
                                sout | "goto L3" | endl;
                                // S_G = { y, x }
                                goto L3;  // jump ahead, do not destruct
                                // S_L-S_G = {}
                                // S_G-S_L = {}
                        } else if (false) {
                                ++i;
                                A z = { "z" };
                                sout | "goto L3-2" | endl;
                                // S_G = { z, y, x }
                                goto L3;
                                // S_L-S_G = {}
                                // S_G-S_L = {z} => destruct z
                        } else {
                                ++i;
                                sout | "goto L4" | endl;
                                // S_G = { y, x }
                                goto L4;  // jump ahead, destruct b/c left block x was defined in
                                // S_L-S_G = {}
                                // S_G-S_L = { y, x } => destruct y, x
                        }
                        // S_L3 = { y, x }
                L3: sout | "L3" | endl;
                        sout | "goto L2-2" | endl;
                        // S_G = { y, x }
                        goto L2; // jump back, do not destruct
                        // S_L-S_G = {}
                        // S_G-S_L = {}
        }
        // S_L4 = {}
        L4: sout | "L4" | endl;
        if (i == 4) {
                sout | "goto L0" | endl;
                // S_G = {}
                goto L0;
                // S_L-S_G = {}
                // S_G-S_L = {}
        }
        // S_G = {}
#ifdef ERR2
        if (i == 5) goto L2; // this is an error in g++ because it skips initialization of y, x
        // S_L-S_G = { y, x } => non-empty, so error
#endif
}

int main() {
        sepDisable(sout);
        for (int i = 0; i < 4; i++) {
                f(i);
        }
        sout | endl;
        g();
        sout | endl;
        h();
}