source: src/tests/references.c@ c0453ca3

//
// Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// references.c --
//
// Author           : Rob Schluntz
// Created On       : Wed Aug 23 16:11:50 2017
// Last Modified By : Rob Schluntz
// Last Modified On : Wed Aug 23 16:12:03
// Update Count     : 2
//

struct Y { int i; };
void ?{}(Y & y) { printf("Default constructing a Y\n"); }
void ?{}(Y & y, Y other) { printf("Copy constructing a Y\n"); }
void ^?{}(Y & y) { printf("Destructing a Y\n"); }
Y ?=?(Y & y, Y other) { printf("Assigning a Y\n"); return y; }
void ?{}(Y & y, int i) { printf("Value constructing a Y %d\n", i); y.i = i; }

struct X { Y & r; Y y; };
void ?{}(X & x) {
        // ensure that r is not implicitly constructed
}
void ?{}(X & x, X other) {
        // ensure that r is not implicitly constructed
}
void ^?{}(X & x) {
        // ensure that r is not implicitly destructed
}
X ?=?(X & x, X other) { return x; }

// ensure that generated functions do not implicitly operate on references
struct Z { Y & r; Y y; };

// test user-defined reference-returning function
int & toref( int * p ) { return *p; }
// test user-defined reference-parameter function
int * toptr( int & r ) { return &r; }

void changeRef( int & r ) {
        r++;
}

// --- temporary code needed to make array of references subscript work.
extern "C" {
  void ** __index(__attribute__ ((unused)) size_t sizeof_T, __attribute__ ((unused)) size_t alignof_T, void **x, ptrdiff_t y) {
    return (void **)((char *)x+y*sizeof(void *));
  }
  void __ctor(void ***dst, void **src) {
    *dst = src;
  }
}
__attribute__((alias("__index"))) forall( dtype T | sized(T) ) T && ?[?]( T & * x, ptrdiff_t y );
__attribute__((alias("__ctor"))) forall( dtype DT ) void ?{}( DT & * & dst, DT & * src);
forall( dtype DT ) void ^?{}( DT & * & ) {}
// --- end of temporary code

int main() {
        int x = 123456, x2 = 789, *p1 = &x, **p2 = &p1, ***p3 = &p2,
                &r1 = x,    &&r2 = r1,   &&&r3 = r2;
        ***p3 = 3;                          // change x
        **p3 = &x;                          // change p1
        *p3 = &p1;                          // change p2
        int y = 0, z = 11, & ar[3] = { x, y, z };    // initialize array of references
        &ar[1] = &z;                        // change reference array element
        typeof( ar[1] ) p = 3;              // is int, i.e., the type of referenced object
        typeof( &ar[1] ) q = &x;            // is int *, i.e., the type of pointer
        _Static_assert( sizeof( ar[1] ) == sizeof( int ), "Array type should be int." );   // is true, i.e., the size of referenced object
        _Static_assert( sizeof( &ar[1] ) == sizeof( int *), "Address of array should be int *." ); // is true, i.e., the size of a reference

        ((int*&)&r3) = &x;                  // change r1, (&*)**r3
        x = 3;
        // test that basic reference properties are true - r1 should be an alias for x
        printf("%d %d %d\n", x, r1, &x == &r1);
        r1 = 12;
        printf("%d %d %d\n", x, r1, &x == &r1);

        // test that functions using basic references work
        printf("%d %d %d %d\n", toref(&x), toref(p1), toptr(r1) == toptr(x), toptr(r1) == &x);

        changeRef( x );
        changeRef( y );
        changeRef( z );
        printf("%d %d %d\n", x, y, z);
        changeRef( r1 );
        printf("%d %d\n", r1, x);

        r3 = 6;                               // change x, ***r3
        printf("x = %d ; x2 = %d\n", x, x2);  // check that x was changed
        &r3 = &x2;                            // change r1 to refer to x2, (&*)**r3
        r3 = 999;                             // modify x2
        printf("x = %d ; x2 = %d\n", x, x2);  // check that x2 was changed
        ((int**&)&&r3) = p2;                  // change r2, (&(&*)*)*r3, ensure explicit cast to reference works
        r3 = 12345;                           // modify x
        printf("x = %d ; x2 = %d\n", x, x2);  // check that x was changed
        &&&r3 = p3;                           // change r3 to p3, (&(&(&*)*)*)r3
        ((int&)r3) = 22222;                   // modify x, ensure explicit cast to reference works
        printf("x = %d ; x2 = %d\n", x, x2);  // check that x was changed

        // test that reference members are not implicitly constructed/destructed/assigned
        X x1, x2 = x1;
        x1 = x2;

        Z z1, z2 = z1;
        Y z1r = 56, z2r = 78;
        &z1.r = &z1r;
        &z2.r = &z2r;

        z1 = z2;

        // test rvalue-to-reference conversion
        {
                struct S { double x, y; };
                void f( int & i, int & j, S & s, int v[] ) {
                        printf("%d %d { %g, %g }, [%d, %d, %d]\n", i, j, s.[x, y], v[0], v[1], v[2]);
                }
                void g(int & i) { printf("%d\n", i); }
                void h(int &&& i) { printf("%d\n", i); }

                int &&& r = 3;  // rvalue to reference
                int i = r;
                printf("%d %d\n", i, r);  // both 3

                g( 3 );          // rvalue to reference
                h( (int &&&)3 ); // rvalue to reference

                int a = 5, b = 4;
                f( 3, a + b, (S){ 1.0, 7.0 }, (int [3]){ 1, 2, 3 } ); // two rvalue to reference
        }
}

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