| /* { dg-do compile } */ |
| /* { dg-options "-O2 -Wformat -Wformat-truncation=1 -ftrack-macro-expansion=0" } */ |
| |
| typedef struct |
| { |
| char a0[0]; |
| /* Separate a0 from a1 to prevent the former from being substituted |
| for the latter and causing false positives. */ |
| int: 8; |
| char a1[1]; |
| char a2[2]; |
| char a3[3]; |
| char a4[4]; |
| char ax[]; |
| } Arrays; |
| |
| char buffer[1024]; |
| #define buffer(size) (buffer + sizeof buffer - size) |
| |
| static int value_range (int min, int max) |
| { |
| extern int value (void); |
| int val = value (); |
| return val < min || max < val ? min : val; |
| } |
| |
| #define R(min, max) value_range (min, max) |
| |
| extern void sink (void*); |
| |
| /* Verify that calls to snprintf whose return value is unused are |
| diagnosed if certain or possible truncation is detected. */ |
| |
| #define T(size, ...) \ |
| __builtin_snprintf (buffer (size), size, __VA_ARGS__), sink (buffer) |
| |
| void test_int_retval_unused (void) |
| { |
| T (2, "%i", 123); /* { dg-warning "output truncated" } */ |
| T (2, "%i", R (1, 99)); /* { dg-warning "output may be truncated" } */ |
| T (2, "%i", R (10, 99)); /* { dg-warning "output truncated" } */ |
| T (3, "%i%i", R (1, 99), R (1, 99)); /* { dg-warning "output may be truncated" } */ |
| } |
| |
| void test_string_retval_unused (const Arrays *ar) |
| { |
| /* At level 1 strings of unknown length are assumed to be empty so |
| the following is not diagnosed. */ |
| T (1, "%-s", ar->a0); |
| /* A one-byte array can only hold an empty string, so the following |
| isn't diagnosed. */ |
| T (1, "%-s", ar->a1); |
| /* Unlike the ar->a0 case above, at level 1, the length of an unknown |
| string that points to an array of known size is assumed to be the |
| size of the array minus 1. */ |
| T (1, "%-s", ar->a2); /* { dg-warning "output may be truncated" } */ |
| T (1, "%-s", ar->a3); /* { dg-warning "output may be truncated" } */ |
| T (1, "%-s", ar->a4); /* { dg-warning "output may be truncated" } */ |
| /* Same as the ar->a0 case above. */ |
| T (1, "%-s", ar->ax); |
| } |
| |
| |
| /* Verify that calls to snprintf whose return value is used are |
| diagnosed only if certain truncation is detected but not when |
| truncation is only possible but not certain. */ |
| |
| volatile int retval; |
| |
| #undef T |
| #define T(size, ...) \ |
| retval = __builtin_snprintf (buffer (size), size, __VA_ARGS__) |
| |
| void test_int_retval_used (void) |
| { |
| T (2, "%i", 123); /* { dg-warning "output truncated" } */ |
| T (2, "%i", R (1, 99)); |
| T (2, "%i", R (10, 99)); /* { dg-warning "output truncated" } */ |
| T (3, "%i%i", R (1, 99), R (1, 99)); |
| } |
| |
| void test_string_retval_used (const Arrays *ar) |
| { |
| T (1, "%-s", ar->a0); |
| T (1, "%-s", ar->a1); |
| T (1, "%-s", ar->a2); |
| T (1, "%-s", ar->a3); |
| T (1, "%-s", ar->a4); |
| T (1, "%-s", "123"); /* { dg-warning "output truncated" } */ |
| } |