/* PR tree-optimization/77671 - missing -Wformat-overflow warning on sprintf overflow with "%s" Negative test verifying that sprintf family calls that must not be transformed into calls to other functions (such as memcpy) are preserved. { dg-do compile } { dg-options "-O2 -Wformat -Wno-format-truncation -Wno-format-zero-length -fdump-tree-optimized" } */ void sink (char*, ...); extern char buffer[]; /* String exactly 4100 characters long (plus the terminating NUL). */ extern const char s4100[4101]; void test_sprintf (const char *s) { /* Macros to test the function call while eignoring and using the return value, respectively. */ #define IGN(...) __builtin_sprintf (buffer, __VA_ARGS__), sink (buffer) #define USE(...) sink (buffer, __builtin_sprintf (buffer, __VA_ARGS__)) /* All of the following calls to sprintf must be emitted (and not transformed into memcpy, strcpy, or similar). */ /* Verify that a sprintf call with output in excess of the maximum of 4095 bytes is not transformed into memcpy/strcpy when its return value is used (the call may fail with EOVERFLOW but the error is only detectable when the function's negative return value indicates errno is valid ). */ USE (s4100); USE ("%s", s4100); /* Same as above but with string of unknown length (which could be in excess of 4K long). */ USE (s); USE ("%s", s); } void test_snprintf (void) { #undef IGN #define IGN(N, ...) __builtin_snprintf (buffer, N, __VA_ARGS__); sink (buffer) /* All of the following calls to sprintf must be emitted (and not transformed into memcpy, strcpy, or similar). */ /* Truncated output could be optimized into strncpy (not done yet). */ IGN (1, "123"); IGN (1, s4100); IGN (1, "%s", "123"); IGN (1, "%s", s4100); /* Output in excess of the maximum of 4095 bytes. */ IGN (4097, s4100); IGN (4097, "%s", s4100); } void test_vsprintf (__builtin_va_list va) { #undef IGN #define IGN(fmt) __builtin_vsprintf (buffer, fmt, va); sink (buffer) /* All of the following calls to vsprintf must be emitted (and not transformed into memcpy, strcpy, or similar). */ /* Output in excess of the maximum of 4095 bytes. */ IGN (s4100); } void test_vsnprintf (__builtin_va_list va) { #undef IGN #define IGN(N, fmt) __builtin_vsnprintf (buffer, N, fmt, va); sink (buffer) /* All of the following calls to vsnprintf must be emitted (and not transformed into memcpy, strcpy, or similar). */ /* Truncated output could be optimized into strncpy (not done yet). */ IGN (1, "123"); IGN (1, s4100); /* Output in excess of the maximum of 4095 bytes. */ IGN (4097, s4100); } /* { dg-final { scan-tree-dump-times "builtin_sprintf" 4 "optimized" } } { dg-final { scan-tree-dump-times "builtin_snprintf" 6 "optimized" } } { dg-final { scan-tree-dump-times "builtin_vsprintf" 1 "optimized" } } { dg-final { scan-tree-dump-times "builtin_vsnprintf" 3 "optimized" } } */ #define S10 "0123456789" #define S100 S10 S10 S10 S10 S10 S10 S10 S10 S10 S10 #define S1000 S100 S100 S100 S100 S100 S100 S100 S100 S100 S100 const char s4100[4101] = S1000 S1000 S1000 S1000 S100;