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/* Test various diagnostics of ill-formed constructs involving labels. */
/* { dg-do compile } */
/* { dg-options "-Wunused" } */
extern void dummy(void);
/* labels must be defined */
void a(void)
{
goto l; /* { dg-error "used but not defined" "no label" } */
}
/* warnings for labels defined but not used, or declared but not defined */
void b(void)
{
__label__ l;
l: /* { dg-warning "defined but not used" "no goto 1" } */
m: /* { dg-warning "defined but not used" "no goto 2" } */
dummy();
}
void c(void)
{
__label__ l; /* { dg-warning "declared but not defined" "only __label__" } */
dummy();
}
/* can't have two labels with the same name in the same function */
void d(void)
{
l: dummy(); /* { dg-message "note: previous definition" "prev def same scope" } */
l: dummy(); /* { dg-error "duplicate label" "dup label same scope" } */
goto l;
}
/* even at different scopes */
void e(void)
{
l: dummy(); /* { dg-message "note: previous definition" "prev def diff scope" } */
{
l: dummy(); /* { dg-error "duplicate label" "dup label diff scope" } */
}
goto l;
}
/* but, with __label__, you can */
void f(void)
{
l: dummy();
{
__label__ l;
l: dummy(); /* { dg-warning "defined but not used" "unused shadow 1" } */
};
goto l; /* this reaches the outer l */
}
/* a __label__ is not visible outside its scope */
void g(void)
{
dummy();
{
__label__ l;
l: dummy();
goto l;
}
goto l; /* { dg-error "used but not defined" "label ref out of scope" } */
}
/* __label__ can appear at top level of a function, too...
... but doesn't provide a definition of the label */
void h(void)
{
__label__ l;
dummy ();
goto l; /* { dg-error "used but not defined" "used, only __label__" } */
}
/* A nested function may not goto a label outside itself */
void i(void)
{
auto void nest(void);
l: nest();
void nest(void)
{
goto l; /* { dg-error "used but not defined" "nest use outer label" } */
}
goto l; /* reaches the outer l */
}
/* which means that a nested function may have its own label with the
same name as the outer function */
void j(void)
{
auto void nest(void);
l: nest();
void nest(void)
{
l: dummy(); /* { dg-warning "defined but not used" "nest label same name" } */
}
goto l; /* reaches the outer l */
}
/* and, turnabout, an outer function may not goto a label in a nested
function */
void k(void)
{
void nest(void)
{
l: dummy(); /* { dg-warning "defined but not used" "outer use nest label" } */
}
goto l; /* { dg-error "used but not defined" "outer use nest label" } */
nest();
}
/* not even with __label__ */
void l(void)
{
void nest(void)
{
__label__ l;
l: dummy(); /* { dg-warning "defined but not used" "outer use nest __label__" } */
}
goto l; /* { dg-error "used but not defined" "outer use nest __label__" } */
nest();
}
/* but if the outer label is declared with __label__, then a nested
function can goto that label (accomplishing a longjmp) */
void m(void)
{
__label__ l;
void nest(void) { goto l; }
nest();
dummy();
l:;
}
/* and that means the nested function cannot have its own label with
the same name as an outer label declared with __label__ */
void n(void)
{
__label__ l; /* { dg-message "note: previous declaration" "outer label decl" } */
void nest(void)
{
l: goto l; /* { dg-error "duplicate label" "inner label defn" } */
}
l:
nest();
}
/* unless the nested function uses __label__ too! */
void o(void)
{
__label__ l;
void nest(void)
{
__label__ l;
l: goto l;
}
l: goto l;
nest();
}
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