llvm-project/clang/test/SemaCXX/warn-memsize-comparison.cpp
Richard Smith 5e9746f520 DR583, DR1512: Implement a rewrite to C++'s 'composite pointer type' rules.
This has two significant effects:

1) Direct relational comparisons between null pointer constants (0 and nullopt)
   and pointers are now ill-formed. This was always the case for C, and it
   appears that C++ only ever permitted by accident. For instance, cases like
     nullptr < &a
   are now rejected.

2) Comparisons and conditional operators between differently-cv-qualified
   pointer types now work, and produce a composite type that both source
   pointer types can convert to (when possible). For instance, comparison
   between 'int **' and 'const int **' is now valid, and uses an intermediate
   type of 'const int *const *'.

Clang previously supported #2 as an extension.

We do not accept the cases in #1 as an extension. I've tested a fair amount of
code to check that this doesn't break it, but if it turns out that someone is
relying on this, we can easily add it back as an extension.

This is a re-commit of r284800.

llvm-svn: 284890
2016-10-21 22:00:42 +00:00

96 lines
4.1 KiB
C++

// RUN: %clang_cc1 -fsyntax-only -verify %s
//
typedef __SIZE_TYPE__ size_t;
extern "C" void *memset(void *, int, size_t);
extern "C" void *memmove(void *s1, const void *s2, size_t n);
extern "C" void *memcpy(void *s1, const void *s2, size_t n);
extern "C" int memcmp(void *s1, const void *s2, size_t n);
extern "C" int strncmp(const char *s1, const char *s2, size_t n);
extern "C" int strncasecmp(const char *s1, const char *s2, size_t n);
extern "C" char *strncpy(char *dst, const char *src, size_t n);
extern "C" char *strncat(char *dst, const char *src, size_t n);
extern "C" char *strndup(const char *src, size_t n);
extern "C" size_t strlcpy(char *dst, const char *src, size_t size);
extern "C" size_t strlcat(char *dst, const char *src, size_t size);
void f() {
char b1[80], b2[80];
if (memset(b1, 0, sizeof(b1) != 0)) {} // \
expected-warning{{size argument in 'memset' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (memset(b1, 0, sizeof(b1)) != 0) {}
if (memmove(b1, b2, sizeof(b1) == 0)) {} // \
expected-warning{{size argument in 'memmove' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (memmove(b1, b2, sizeof(b1)) == 0) {}
// FIXME: This fixit is bogus.
if (memcpy(b1, b2, sizeof(b1) < 0)) {} // \
expected-warning{{size argument in 'memcpy' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (memcpy(b1, b2, sizeof(b1)) < 0) {} // expected-error {{ordered comparison between pointer and zero}}
if (memcmp(b1, b2, sizeof(b1) <= 0)) {} // \
expected-warning{{size argument in 'memcmp' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (memcmp(b1, b2, sizeof(b1)) <= 0) {}
if (strncmp(b1, b2, sizeof(b1) > 0)) {} // \
expected-warning{{size argument in 'strncmp' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strncmp(b1, b2, sizeof(b1)) > 0) {}
if (strncasecmp(b1, b2, sizeof(b1) >= 0)) {} // \
expected-warning{{size argument in 'strncasecmp' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strncasecmp(b1, b2, sizeof(b1)) >= 0) {}
if (strncpy(b1, b2, sizeof(b1) == 0 || true)) {} // \
expected-warning{{size argument in 'strncpy' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strncpy(b1, b2, sizeof(b1)) == 0 || true) {}
// FIXME: This fixit is bogus.
if (strncat(b1, b2, sizeof(b1) - 1 >= 0 && true)) {} // \
expected-warning{{size argument in 'strncat' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strncat(b1, b2, sizeof(b1) - 1) >= 0 && true) {} // expected-error {{ordered comparison between pointer and zero}}
if (strndup(b1, sizeof(b1) != 0)) {} // \
expected-warning{{size argument in 'strndup' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strndup(b1, sizeof(b1)) != 0) {}
if (strlcpy(b1, b2, sizeof(b1) != 0)) {} // \
expected-warning{{size argument in 'strlcpy' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strlcpy(b1, b2, sizeof(b1)) != 0) {}
if (strlcat(b1, b2, sizeof(b1) != 0)) {} // \
expected-warning{{size argument in 'strlcat' call is a comparison}} \
expected-note {{did you mean to compare}} \
expected-note {{explicitly cast the argument}}
if (strlcat(b1, b2, sizeof(b1)) != 0) {}
if (memset(b1, 0, sizeof(b1) / 2)) {}
if (memset(b1, 0, sizeof(b1) >> 2)) {}
if (memset(b1, 0, 4 << 2)) {}
if (memset(b1, 0, 4 + 2)) {}
if (memset(b1, 0, 4 - 2)) {}
if (memset(b1, 0, 4 * 2)) {}
if (memset(b1, 0, (size_t)(sizeof(b1) != 0))) {}
}