[C++ PATCH] Deprecate -ffriend-injection

[official-gcc.git] / gcc / testsuite / c-c++-common / Wrestrict.c

/* PR 35503 - Warn about restricted pointers
   { dg-do compile }
   { dg-options "-O2 -Wrestrict -ftrack-macro-expansion=0" } */

#include "../gcc.dg/range.h"

#if !defined LINE
# define LINE 0
#endif

#if __cplusplus
#  define restrict __restrict
extern "C" {
#endif

extern void* memcpy (void* restrict, const void* restrict, size_t);
extern void* mempcpy (void* restrict, const void* restrict, size_t);
extern void* memmove (void*, const void*, size_t);

extern char* stpcpy (char* restrict, const char* restrict);

extern char* strcat (char* restrict, const char* restrict);
extern char* strcpy (char* restrict, const char* restrict);
extern char* strncpy (char* restrict, const char* restrict, size_t);

#if __cplusplus
}   /* extern "C" */
#endif

void sink (void*, ...);

struct MemArrays
{
  char a8[8];
  char a16[16];
  char ax[];
};

/* Exercise memcpy with constant or known arguments.  */

void test_memcpy_cst (void *d, const void *s)
{
#undef T
#define T(dst, src, n) do {                             \
    if (!LINE || LINE == __LINE__) {                    \
      char a[9] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };        \
      void *pd = (dst);                                 \
      const void *ps = (src);                           \
      memcpy (pd, ps, (n));                             \
      sink (a, pd, ps);                                 \
    }                                                   \
  } while (0)

  T (a, a, 0);
  T (a, s = a, 3);           /* { dg-warning "\\\[-Wrestrict" "memcpy" } */

  /* This isn't detected because memcpy calls with small power-of-2 sizes
     are intentionally folded into safe copies equivalent to memmove.
     It's marked xfail only because there is value in detecting such
     invalid calls for portability, and as a reminder of why it isn't
     diagnosed.  */
  T (a, a + 1, 1);           /* { dg-warning "\\\[-Wrestrict" "memcpy with a small power of 2 size" { xfail *-*-* } } */
  T (a, a + 3, 3);
  T (a, a + 3, 5);           /* { dg-warning "\\\[-Wrestrict" "memcpy" } */

  {
    char a[3] = { 1, 2, 3 };

    /* Verify that a call to memcpy with an exact overlap is diagnosed
       (also tested above) but an excplicit one to __builtin_memcpy is
       not.  See bug 32667 for the rationale.  */
    (memcpy)(a, a, sizeof a);   /* { dg-warning "source argument is the same as destination" "memcpy" } */
    sink (a);

    __builtin_memcpy (a, a, sizeof a);
    sink (a);
  }

  {
    char a[3][7];
    sink (a);

    void *d = a[0];
    const void *s = a[1];
    memcpy (d, s, sizeof a[0]);
    sink (&a);

    d = a[0];
    s = a[1];
    /* The following is only diagnosed for sizes that aren't small
       powers of 2.  */
    memcpy (d, s, sizeof a[0] + 2); /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&a);

    d = a[0] + 1;
    s = a[1] + 1;
    memcpy (d, s, sizeof a[0]);
    sink (&a);

    d = a[0] + 1;
    s = a[1] + 1;
    memcpy (d, s, sizeof a[0] + 2); /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&a);
  }

  {
    struct {
      char a[7];
      char b[7];
      char c[7];
    } x;
    sink (&x);

    void *d = x.a;
    const void *s = x.b;
    memcpy (d, s, sizeof x.a);
    sink (&x);

    d = x.a;
    s = x.a;
    memcpy (d, s, sizeof x.a);    /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&x);

    d = x.a + 4;
    s = x.b;
    memcpy (d, s, sizeof x.a);    /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&x);

    d = x.a + 6;
    s = x.b;
    memcpy (d, s, 1);
    sink (&x);

    d = x.a + 7;
    s = x.b;
    memcpy (d, s, 3);             /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&x);

    d = x.a + 7;
    s = x.b + 1;
    memcpy (d, s, 1);
    sink (&x);

    d = x.b;
    s = x.a;
    memcpy (d, s, 1);
    sink (&x);

    d = x.b;
    s = x.a;
    memcpy (d, s, sizeof x.b);
    sink (&x);

    d = x.b + 2;
    s = x.a + 1;
    memcpy (d, s, sizeof x.b);
    sink (&x);

    d = x.b + 2;
    s = x.a + 2;
    memcpy (d, s, sizeof x.b);
    sink (&x);

    d = x.b + 2;
    s = x.a + 3;
    memcpy (d, s, sizeof x.b);    /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
    sink (&x);
  }

  {
#undef T
#define T(dst, src, n) do {                             \
    if (!LINE || LINE == __LINE__) {                    \
      char a[9] = { 0, 1, 2, 3, 4, 5, 6, 7, 8 };        \
      memcpy ((dst), (src), (n));                       \
      sink (a);                                         \
    }                                                   \
    } while (0)

    /* Verify the offset of the overlap is the same regardless of whether
       the destination is at lower or higher offset than the source.  */
    T (a, a + 1, 5);             /* { dg-warning "accessing 5 bytes at offsets 0 and 1 overlaps 4 bytes at offset 1" "memcpy" } */
    T (a, a + 2, 5);             /* { dg-warning "accessing 5 bytes at offsets 0 and 2 overlaps 3 bytes at offset 2" "memcpy" } */
    T (a, a + 3, 5);             /* { dg-warning "accessing 5 bytes at offsets 0 and 3 overlaps 2 bytes at offset 3" "memcpy" } */

    T (a + 1, a, 5);             /* { dg-warning "accessing 5 bytes at offsets 1 and 0 overlaps 4 bytes at offset 1" "memcpy" } */
    T (a + 2, a, 5);             /* { dg-warning "accessing 5 bytes at offsets 2 and 0 overlaps 3 bytes at offset 2" "memcpy" } */
    T (a + 3, a, 5);             /* { dg-warning "accessing 5 bytes at offsets 3 and 0 overlaps 2 bytes at offset 3" "memcpy" } */
  }
}

/* Exercise memcpy with destination or source offset or size in
   a determinate range.  */

void test_memcpy_range (char *d, size_t sz)
{
#undef T
#define T(dst, src, n) do {                     \
    if (!LINE || LINE == __LINE__) {            \
      char a[9] = { 0, 1, 2, 3, 4, 5, 6, 7, 8 };        \
      void *pd = (dst);                                 \
      const void *ps = (src);                           \
      memcpy (pd, ps, (n));                             \
      sink (a, pd, ps);                                 \
    }                                                   \
  } while (0)

  ptrdiff_t ir = SR (2, 3);
  T (a + ir, a, 0);
  T (a + ir, a, 1);
  T (a + ir, a, 2);
  T (a + ir, a, 3);
  /* The following fails because the size is a small power of 2.  */
  T (a + ir, a, 4);               /* { dg-warning "accessing 4 bytes at offsets \\\[2, 3] and 0 overlaps between 1 and 2 bytes at offset \\\[3, 2]" "memcpy" { xfail *-*-*} } */
  T (a + ir, a, 5);               /* { dg-warning "accessing 5 bytes at offsets \\\[2, 3] and 0 overlaps between 2 and 3 bytes at offset \\\[2, 3]" "memcpy" } */

  T (d + ir, d, 0);
  T (d + ir, d, 1);
  T (d + ir, d, 2);
  T (d + ir, d, 3);
  T (d + ir, d, 4);               /* { dg-warning "accessing 4 bytes at offsets \\\[2, 3] and 0 overlaps 1 byte at offset 3" "bug 79220" { xfail *-*-* } } */
  T (d + ir, d, 5);               /* { dg-warning "accessing 5 bytes at offsets \\\[2, 3] and 0 overlaps between 2 and 3 bytes at offset \\\[2, 3]" "memcpy" } */

  /* Because the size is constant and a power of 2 the following is
     folded too early to detect the overlap.  */
  T (d + ir, d, 4);               /* { dg-warning "accessing 4 bytes at offsets \\\[2, 3] and 0 overlaps 2 byte at offset 2" "" { xfail *-*-* } } */
  T (d + ir, d, 5);               /* { dg-warning "accessing 5 bytes at offsets \\\[2, 3] and 0 overlaps between 2 and 3 bytes at offset \\\[2, 3]" "memcpy" } */

  /* Exercise the full range of size_t.  */
  T (d + sz, d, 0);
  T (d + sz, d, 1);
  T (d + sz, d, 9);

  T (a, a + 1, SR (0, 1));
  T (a, a + 1, SR (0, 2));
  T (a, a + 1, SR (1, 2));
  T (a, a + 1, SR (2, 3));         /* { dg-warning "accessing between 2 and 3 bytes at offsets 0 and 1 overlaps between 1 and 2 bytes at offset 1" "memcpy" } */
  T (a, a + 1, UR (2, DIFF_MAX + (size_t)1));  /* { dg-warning "accessing 2 or more bytes at offsets 0 and 1 overlaps 1 or more bytes at offset 1" "memcpy" } */
  T (a, a + 1, UR (2, SIZE_MAX - 1));        /* { dg-warning "accessing 2 or more bytes at offsets 0 and 1 overlaps 1 or more bytes at offset 1" "memcpy" } */
  T (a, a + 2, SR (2, 3));
  T (a, a + 2, SR (3, 4));         /* { dg-warning "accessing between 3 and 4 bytes at offsets 0 and 2 overlaps between 1 and 2 bytes at offset 2" "memcpy" } */
  T (a, a + 3, SR (3, 4));
  T (a, a + 3, SR (4, 5));         /* { dg-warning "accessing between 4 and 5 bytes at offsets 0 and 3 overlaps between 1 and 2 bytes at offset 3" "memcpy" } */
  T (a, a + 3, SR (5, 6));         /* { dg-warning "accessing between 5 and 6 bytes at offsets 0 and 3 overlaps between 2 and 3 bytes at offset 3" "memcpy" } */

  T (a + 1, a, SR (0, 1));
  T (a + 1, a, SR (0, 2));
  T (a + 1, a, SR (1, 2));
  T (a + 1, a, SR (2, 3));         /* { dg-warning "accessing between 2 and 3 bytes at offsets 1 and 0 overlaps between 1 and 2 bytes at offset 1" "memcpy" } */
  T (a + 1, a, UR (2, DIFF_MAX + (size_t)1)); /* { dg-warning "accessing 2 or more bytes at offsets 1 and 0 overlaps 1 or more bytes at offset 1" "memcpy" } */
  T (a + 1, a, UR (2, SIZE_MAX - 1)); /* { dg-warning "accessing 2 or more bytes at offsets 1 and 0 overlaps 1 or more bytes at offset 1" "memcpy" } */
  T (a + 2, a, SR (2, 3));
  T (a + 2, a, SR (3, 4));         /* { dg-warning "accessing between 3 and 4 bytes at offsets 2 and 0 overlaps between 1 and 2 bytes at offset 2" "memcpy" } */
  T (a + 3, a, SR (3, 4));
  T (a + 3, a, SR (4, 5));         /* { dg-warning "accessing between 4 and 5 bytes at offsets 3 and 0 overlaps between 1 and 2 bytes at offset 3" "memcpy" } */
  T (a + 3, a, SR (5, 6));         /* { dg-warning "accessing between 5 and 6 bytes at offsets 3 and 0 overlaps between 2 and 3 bytes at offset 3" "memcpy" } */

  ir = SR (2, 5);
  T (a, a + ir, 4);
  T (a, a + ir, 5);                /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[2, 5] overlaps between 1 and 3 bytes at offset \\\[2, 4]" "memcpy" } */
  T (a, a + ir, 6);                /* { dg-warning "accessing 6 bytes at offsets 0 and \\\[2, 5] overlaps between 3 and 4 bytes at offset \\\[2, 3]" "memcpy" } */

  /* Below, there are two possible regions for the source of the copy:
       1) one just before the high end of the address space that's 3
          bytes large close to the lower end of the offset range, and
       2) another in the [DIFF_MIN, -8] range from D and so at least
          8 bytes in size
     A copy from (1) overlaps but one from (2) does not.  Verify that
     the copy is not diagnosed.  (This test case was reduced from
     the Linux kernel.) */
  T (d, d + UR (DIFF_MAX - 3, SIZE_MAX - 7), 5);
  T (d, d + UR (DIFF_MAX - 3, SIZE_MAX - 7), 6);
  T (d, d + UR (DIFF_MAX - 3, SIZE_MAX - 7), 7);
  T (d, d + UR (DIFF_MAX - 3, SIZE_MAX - 7), 9);

  T (d + UR (DIFF_MAX - 3, SIZE_MAX - 7), d, 5);
  T (d + UR (DIFF_MAX - 3, SIZE_MAX - 7), d, 6);
  T (d + UR (DIFF_MAX - 3, SIZE_MAX - 7), d, 7);
  T (d + UR (DIFF_MAX - 3, SIZE_MAX - 7), d, 9);

  {
    /* Create an offset in the range [0, -1].  */
    size_t o = sz << 1;
    T (d, d + o, 12345);
    T (d + o, d, 23456);
  }

  /* Exercise memcpy with both destination and source pointer offsets
     in some known range.  */
  size_t n = UR (3, 4);
  T (a + SR (1, 3), a + SR (1, 3), n);  /* { dg-warning "accessing between 3 and 4 bytes at offsets \\\[1, 3] and \\\[1, 3] overlaps between 1 and 4 bytes at offset \\\[1, 3]" "memcpy" } */

  /* This is an interesting case:
       memcpy (a + i, a + j, n) with i in [1, 3], j in [2, 3], and n in [3, 4]
     we have the following possibilities ('^' denotesthe destination offset,
     '*' marks the overlap, and '?' is the possible overlap for large n):
       i j | a = 012345678   SIZ  OFF (size and offset of the overlap)
       1 2 |      ^**?       2-3   2
       1 3 |      ^ *?       1-2   3
       2 2 |       ***?      3-4   2
       2 3 |       ^**?      2-3   3
       3 3 |        ***?     3-4   3
     There are two ways to present the results:
     1) overlaps between 1 and 4 bytes at offset [2, 3]
     2) overlaps between 1 and 4 bytes at offset 2.  */
  T (a + SR (1, 3), a + SR (2, 3), n);  /* { dg-warning "accessing between 3 and 4 bytes at offsets \\\[1, 3] and \\\[2, 3] overlaps between 1 and 4 bytes at offset \\\[2, 3]" "memcpy" } */
  T (a + SR (1, 3), a + SR (3, 4), n);

  T (a + SR (2, 3), a + SR (3, 4), n);  /* { dg-warning "accessing between 3 and 4 bytes at offsets \\\[2, 3] and \\\[3, 4] overlaps between 1 and 4 bytes at offset \\\[3, 4]" "memcpy" } */

  T (a + SR (1, 3), a + SR (4, 5), n);
  T (a + SR (2, 3), a + SR (4, 5), n);
  T (a + SR (3, 4), a + SR (4, 5), n);  /* { dg-warning "accessing between 3 and 4 bytes at offsets \\\[3, 4] and \\\[4, 5] overlaps between 1 and 4 bytes at offset \\\[4, 5]" "memcpy" } */

  /* Exercise the full range of size_t.  */
  T (d, d + sz, 0);
  T (d, d + sz, 1);
  T (d, d + sz, 9);
}

/* Exercise memcpy with offset and/or size in a determinate anti-range.  */

void test_memcpy_anti_range (char *d, const char *s)
{
  T (d, d + SAR (0, 3), 1);
  T (d, d + SAR (0, 3), 2);
  T (d, d + SAR (0, 3), 3);
  T (d, d + SAR (0, 3), DIFF_MAX - 2);   /* { dg-warning "overlaps \[0-9\]+ bytes at offset 2" } */
  T (d, d + SAR (0, 3), DIFF_MAX - 1);   /* { dg-warning "overlaps \[0-9\]+ bytes at offset 1" } */
  T (d, d + SAR (0, 3), DIFF_MAX);       /* { dg-warning "overlaps \[0-9\]+ bytes at offset 0" } */

  T (d, d + SAR (0, 3), UR (DIFF_MAX - 2, DIFF_MAX));               /* { dg-warning "accessing \[0-9\]+ or more bytes at offsets 0 and \\\[-?\[0-9\]+, -?\[0-9\]+] overlaps \[0-9\]+ bytes at offset 2" } */

  /* Verify that a size in an anti-range ~[0, N] where N >= PTRDIFF_MAX
     doesn't trigger a warning.  */
  T (d, s, UAR (1, DIFF_MAX - 1));
  T (d, s, UAR (1, DIFF_MAX));
  T (d, s, UAR (1, SIZE_MAX - 1));

  /* This causes the last dg-warning test to fail for some reason.
     T (d, s, UAR (1, SIZE_MAX)); */
}

/* Verify calls to memcpy() where the combination of offsets in some
   range and size is such that either overlap is unavoidable or one
   or both offsets would exceed the maximum size of an object
   (DIFF_MAX).  */

void test_memcpy_range_exceed (char *d, const char *s)
{
  /* Verify offset and size both in some range.  The memcpy checking
     is less strict than that of string functions like strncpy and
     doesn't trigger unless the overlap is certain.  The following
     overlaps for (r == 3 && n > 3) but not, for example, for
     (r == 4 && n == 4), and so it's not diagnosed.  */
  ptrdiff_t i = SR (3, 5);
  size_t n = UR (4, 6);

  T (a, a + i, n);
  T (a + i, a, n);
  /* Ditto for objects of unknown sizes.  */
  T (d, d + i, n);
  T (d + i, d, n);

  /* Verify that a warning is issued for a copy between two regions
     whose aggregate size would exceed DIFF_MAX if it were to not
     overlap.  */
  T (d, s, DIFF_MAX / 2);
  T (d, s, DIFF_MAX / 2 + 1);   /* { dg-warning "overlaps 1 byte" "memcpy" } */
  T (d, s, DIFF_MAX / 2 + 2);   /* { dg-warning "overlaps 3 bytes" "memcpy" } */
  T (d, s, DIFF_MAX / 2 + 3);   /* { dg-warning "overlaps 5 bytes" "memcpy" } */

  i = SR (DIFF_MAX - 2, DIFF_MAX);

  /* Verify a warning for an out-of-bounds offset range and constant
     size addition.  */
  T (d, d + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 0 and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 byte" "memcpy" } */
  T (d + i, d, 3);   /* { dg-warning "accessing 3 bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and 0 overlaps 1 byte" "memcpy" } */

  T (d + 1, d + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 1 and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 byte" "memcpy" } */
  T (d + i, d + 1, 3);   /* { dg-warning "accessing 3 bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and 1 overlaps 1 byte" "memcpy" } */

  /* Verify that the warnings above are independent of whether the source
     and destination are known to be based on the same object.  */
  T (d, s + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 0 and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 byte" "memcpy" } */
  T (d + i, s, 3);   /* { dg-warning "accessing 3 bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and 0 overlaps 1 byte" "memcpy" } */

  T (d + 1, s + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 1 and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 byte" "memcpy" } */
  T (d + i, s + 1, 3);   /* { dg-warning "accessing 3 bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and 1 overlaps 1 byte" "memcpy" } */

#if __SIZEOF_SIZE_T__ == 8
  /* Verfiy the offset and size computation is correct.  The overlap
     offset mentioned in the warning plus sthe size of the access must
     not exceed DIFF_MAX.  */
  T (d, d + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[9223372036854775805, 9223372036854775807] overlaps 3 bytes at offset 9223372036854775802" "LP64" { target lp64 } } */
  T (d + i, d, 5);   /* { dg-warning "accessing 5 bytes at offsets \\\[9223372036854775805, 9223372036854775807] and 0 overlaps 3 bytes at offset 9223372036854775802" "LP64" { target lp64 } } */

  T (d, s + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[9223372036854775805, 9223372036854775807] overlaps 3 bytes at offset 9223372036854775802" "LP64" { target lp64 } } */
  T (d + i, s, 5);   /* { dg-warning "accessing 5 bytes at offsets \\\[9223372036854775805, 9223372036854775807] and 0 overlaps 3 bytes at offset 9223372036854775802" "LP64" { target lp64 } } */
#elif __SIZEOF_SIZE_T__ == 4
  T (d, d + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[2147483645, 2147483647] overlaps 3 bytes at offset 2147483642" "ILP32" { target ilp32 } } */
  T (d + i, d, 5);   /* { dg-warning "accessing 5 bytes at offsets \\\[2147483645, 2147483647] and 0 overlaps 3 bytes at offset 2147483642" "ILP32" { target ilp32} } */

  T (d, s + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[2147483645, 2147483647] overlaps 3 bytes at offset 2147483642" "ILP32" { target ilp32 } } */
  T (d + i, s, 5);   /* { dg-warning "accessing 5 bytes at offsets \\\[2147483645, 2147483647] and 0 overlaps 3 bytes at offset 2147483642" "ILP32" { target ilp32} } */
#endif

  ptrdiff_t j = SR (DIFF_MAX - 9, DIFF_MAX - 1);
  i = SR (DIFF_MAX - 5, DIFF_MAX - 1);
  n = UR (4, 5);
  T (d + i, d + j, n);

  n = UR (4, DIFF_MAX - 1);
  T (d + i, d + j, n);

  n = UR (4, SIZE_MAX - 1);
  T (d + i, d + j, n);

  j = SR (DIFF_MAX - 8, DIFF_MAX - 1);
  T (d + i, d + j, n);

  j = SR (DIFF_MAX - 7, DIFF_MAX - 1);
  T (d + i, d + j, n);   /* { dg-warning "accessing 4( or more)? bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and \\\[\[0-9\]+, \[0-9\]+] overlaps" "memcpy" } */

  j = SR (DIFF_MAX - 6, DIFF_MAX - 1);
  T (d + i, d + j, n);   /* { dg-warning "accessing 4( or more)? bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and \\\[\[0-9\]+, \[0-9\]+] overlaps" "memcpy" } */

  n = UR (3, DIFF_MAX);
  T (d + i, d + j, n);

  j = SR (DIFF_MAX - 6, DIFF_MAX - 1);
  T (d + i, d + j, n);

  j = SR (DIFF_MAX - 5, DIFF_MAX - 1);
  T (d + i, d + j, n);   /* { dg-warning "accessing 3 or more bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 or more bytes" "memcpy" } */

  j = SR (DIFF_MAX - 4, DIFF_MAX - 1);
  T (d + i, d + j, n);   /* { dg-warning "accessing 3 or more bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 or more bytes" "memcpy" } */

  j = SR (DIFF_MAX - 2, DIFF_MAX - 1);
  T (d + i, d + j, n);   /* { dg-warning "accessing 3 or more bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and \\\[\[0-9\]+, \[0-9\]+] overlaps 1 or more bytes" "memcpy" } */
}

/* Exercise memcpy with destination and source of unknown size.  */

void test_memcpy_var (char *d, const char *s)
{
  size_t n = unsigned_value ();

  memcpy (d, d, 0);
  sink (d);

  memcpy (d, d, n);               /* { dg-warning "source argument is the same as destination" "memcpy" } */
  sink (d);

  memcpy (d, &d[0], n);           /* { dg-warning "source argument is the same as destination" "memcpy" } */
  sink (d);

  memcpy (&d[0], d,  n);          /* { dg-warning "source argument is the same as destination" "memcpy" } */
  sink (d);

  s = d;
  memcpy (d, s, n);               /* { dg-warning "source argument is the same as destination" "memcpy" } */
  sink (d);

  /* The following overlaps if n is greater than 1.  */
  s = d + 1;
  memcpy (d, s, n);
  sink (d);

  s = d + n;
  memcpy (d, s, n);
  sink (d);

  s = d + signed_value ();
  memcpy (d, s, unsigned_value ());
  sink (d);

  s = d + 3;
  n = 1;
  memcpy (d, s, n);
  sink (d);

  s = d + 3;
  n = 2;
  memcpy (d, s, n);
  sink (d);

  s = d + 3;
  n = 3;
  memcpy (d, s, n);
  sink (d);

  s = d + 3;
  n = 4;
  memcpy (d, s, n);               /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
  sink (d);

  s = d + 5;
  n = 7;
  memcpy (d, s, n);               /* { dg-warning "\\\[-Wrestrict" "memcpy" } */

  n = UR (0, 1);
  s = d;
  memcpy (d, s, n);               /* { dg-warning "\\\[-Wrestrict" "memcpy" } */
}


void test_memcpy_memarrray (struct MemArrays *p)
{
#undef T
#define T(dst, src, n) do {                     \
    if (!LINE || LINE == __LINE__) {            \
      void *pd = (dst);                         \
      const void *ps = (src);                   \
      memcpy (pd, ps, (n));                     \
      sink (pd, ps);                            \
    }                                           \
  } while (0)

  T (p->a8, p->a8, 0);
  T (p->a8, p->a8 + 1, 1);
  T (p->a8, p->a8 + 2, 2);
  T (p->a8, p->a8 + 8, 1);

  T (p->a8, p->a8 + 2, 3);        /* { dg-warning "accessing 3 bytes at offsets 0 and 2 overlaps 1 byte at offset 2" } */
}

/* Exercise the absence of warnings with memmove.  */

void test_memmove (void)
{
  {
    char d[7];
    sink (d);

    const void *s = d;
    memmove (d, s, 7);
    sink (d);

    s = d + 1;
    memmove (d, s, 6);
    sink (d);

    s = d + 2;
    memmove (d + 1, s, 5);
    sink (d);
  }
}

/* Exercise strcat with constant or known arguments.  */

void test_strcat_cst (const char *s)
{
#undef T
#define T(init, dst, src) do {                          \
    if (!LINE || LINE == __LINE__) {                    \
      char a[9] = init;                                 \
      char *pd = (dst);                                 \
      const char *ps = (src);                           \
      strcat (pd, ps);                                  \
      sink (a, pd, ps);                                 \
    }                                                   \
  } while (0)

  T ("0",   a, a);                /* { dg-warning "source argument is the same as destination" "strcat" } */
  T ("01",  a, a);                /* { dg-warning "source argument is the same as destination" "strcat" } */
  T ("012", a, a);                /* { dg-warning "source argument is the same as destination" "strcat" } */
  /* The 3 bytes "12\0" being appended to "012" overwrite the final NUL.  */
  T ("012", a, a + 1);            /* { dg-warning "accessing 3 bytes at offsets 0 and 1 overlaps 1 byte at offset 3" "strcat" } */
  T ("012", a, a + 2);            /* { dg-warning "accessing 2 bytes at offsets 0 and 2 overlaps 1 byte at offset 3" "strcat" } */
  /* The nul copied from a[3] to a[3] overwrites itself so this is
     diagnosed.  */
  T ("012", a, a + 3);            /* { dg-warning "accessing 1 byte at offsets 0 and 3 overlaps 1 byte at offset 3" "strcat" } */

  T ("012", a, a + 4);
  T ("012", a, a + 5);
  T ("012", a, a + 6);
  T ("012", a, a + 7);
  T ("012", a, a + 8);

  T ("0",   a + 1, a);            /* { dg-warning "accessing 2 bytes at offsets 1 and 0 overlaps 1 byte at offset 1" "strcat" } */
  T ("0",   a + 2, a);

  /* The first of the two offsets in the diagnostic for strcat is that
     of the first write into the destination, not that of the initial
     read from it to compute its length.  */
  T ("01",  a + 1, a);            /* { dg-warning "accessing 3 bytes at offsets 1 and 0 overlaps 1 byte at offset 2" "strcat" } */
  T ("01",  a + 2, a);            /* { dg-warning "accessing 3 bytes at offsets 2 and 0 overlaps 1 byte at offset 2" "strcat" } */
  T ("01",  a + 3, a);

  T ("012", a + 1, a);            /* { dg-warning "accessing 4 bytes at offsets 1 and 0 overlaps 1 byte at offset 3" "strcat" } */
  T ("012", a + 2, a);            /* { dg-warning "accessing 4 bytes at offsets 2 and 0 overlaps 1 byte at offset 3" "strcat" } */
  T ("012", a + 3, a);            /* { dg-warning "accessing 4 bytes at offsets 3 and 0 overlaps 1 byte at offset 3 " "strcat" } */
  T ("012", a + 4, a);
  T ("012", a + 5, a);

  /* Verify that the obviously benign cases below aren't diagnosed.  */
  T ("012",      a, "012");
  T ("012",      a, s);
  T ("01234567", a, s);
}

/* Exercise strcat with destination and source of unknown length.  */

void test_strcat_var (char *d, const char *s)
{
#undef T
#define T(dst, src) do {                                \
    if (!LINE || LINE == __LINE__) {                    \
      char *pd = (dst);                                 \
      const char *ps = (src);                           \
      strcat (pd, ps);                                  \
      sink (pd, ps);                                    \
    }                                                   \
  } while (0)

  T (d, d);                       /* { dg-warning "source argument is the same as destination" "strcat" } */
  T (d, d + 1);                   /* { dg-warning "accessing 2 or more bytes at offsets 0 and 1 may overlap 1 byte" "strcat" } */
  T (d, d + 2);                   /* { dg-warning "accessing 3 or more bytes at offsets 0 and 2 may overlap 1 byte at offset 2" "strcat" } */
  T (d, d + 999);                 /* { dg-warning "accessing 1000 or more bytes at offsets 0 and 999 may overlap 1 byte at offset 999" "strcat" } */

  /* The source string must be at least 100 bytes in length for the copy
     below to overlap.  */
  T (d, d + -99);                 /* { dg-warning "accessing 100 or more bytes at offsets 0 and -99 may overlap 1 byte" "strcat" } */

  size_t n = unsigned_value ();

  T (d + n, d + n);                       /* { dg-warning "\\\[-Wrestrict" "strcat" } */

  /* Verify that the obviously benign cases below aren't diagnosed.  */
  T (d, "012");
  T (d + 1, "0123");
  T (d + n, "01234");
  T (d, s);
  T (d + 1, s);
  T (d + n, s);

  /* Since the offset is unknown the overlap in the call below, while
     possible, is certainly not inevitable.  Conservatively, it should
     not be diagnosed.  For safety, an argument for diagnosing can be
     made.  It's a judgment call, partly determined by the effort and
     complexity of treating this case differently from other similar
     to it.   */
  T (d, d + n); /* { dg-warning "may overlap" "strcat" } */
}

/* Exercise strcpy with constant or known arguments.  */

void test_strcpy_cst (ptrdiff_t i)
{
#undef T
#define T(init, dst, src) do {                          \
    if (!LINE || LINE == __LINE__) {                    \
      char a[8] = init;                                 \
      char *pd = (dst);                                 \
      const char *ps = (src);                           \
      strcpy (pd, ps);                                  \
      sink (a, pd, ps);                                 \
    }                                                   \
  } while (0)

  T ("012", a, a);                /* { dg-warning "source argument is the same as destination" "strcpy" } */
  T ("012", a, a + 1);            /* { dg-warning "accessing 3 bytes at offsets 0 and 1 overlaps 2 bytes at offset 1" "strcpy" } */
  T ("012", a, a + 2);
  T ("012", a, a + 3);
  /* The following doesn't overlap but it should trigger -Wstringop-overflow
     for reading past the end.  */
  T ("012", a, a + sizeof a);

  /* The terminating nul written to d[2] overwrites s[0].  */
  T ("0123", a, a + 2);           /* { dg-warning "accessing 3 bytes at offsets 0 and 2 overlaps 1 byte at offset 2" } */

  /* The '5' copied from s[2] to d[2] overwrites s[0].  */
  T ("01234", a, a + 2);          /* { dg-warning "accessing 4 bytes at offsets 0 and 2 overlaps 2 bytes at offset 2" } */

  /* This happens to be safe in GCC but it's still wrong.  */
  T ("012", a, a);                /* { dg-warning "source argument is the same as destination" "strcpy" } */

  T ("012", a + 1, a);            /* { dg-warning "accessing 4 bytes at offsets 1 and 0 overlaps 3 bytes at offset 1" "strcpy" } */
  T ("012", a + 2, a);            /* { dg-warning "accessing 4 bytes at offsets 2 and 0 overlaps 2 bytes at offset 2" "strcpy" } */
  T ("012", a + 3, a);            /* { dg-warning "accessing 4 bytes at offsets 3 and 0 overlaps 1 byte at offset 3" "strcpy" } */
  T ("012", a + 4, a);
  /* The following doesn't overlap but it should trigger -Wstrinop-ovewrflow
     for writing past the end.  */
  T ("012", a + sizeof a, a);
}

/* Exercise strcpy with constant or known arguments offset by a range.
   The tests verify the use of the lower bound of the range which is
   more restrictive than using the upper bound for positive values.  */

void test_strcpy_range (void)
{
#undef T
#define T(N, init, dst, src)                    \
  do {                                          \
    if (!LINE || LINE == __LINE__) {            \
      char a[N] = init;                         \
      char *pd = (dst);                         \
      const char *ps = (src);                   \
      strcpy (pd, ps);                          \
      sink (a, pd, ps);                         \
    }                                           \
  } while (0)

  ptrdiff_t r;

  r = SR (0, 1);
  T (8, "0", a + r, a);   /* { dg-warning "accessing between 1 and 2 bytes at offsets \\\[0, 1] and 0 overlaps up to 2 bytes at offset \\\[0, 1]" "strcpy" { xfail *-*-*} } */

  r = SR (2, 5);
  T (8, "01",  a + r, a);            /* { dg-warning "accessing 3 bytes at offsets \\\[2, 5] and 0 may overlap 1 byte at offset 2" } */
  T (8, "012", a + r, a);            /* { dg-warning "accessing 4 bytes at offsets \\\[2, 5] and 0 may overlap up to 2 bytes at offset \\\[3, 2]" "strcpy" } */

  /* The highest offset to which to copy without overflowing the 8-byte
     destination is 3 and that overlaps 2 bytes.  */
  T (8, "0123", a + r, a);           /* { dg-warning "accessing 5 bytes at offsets \\\[2, 5] and 0 overlaps between 2 and 3 bytes at offset \\\[2, 3]" "strcpy" } */

  /* With a 9-byte destination the highest offset is 4 and that still
     overlaps 1 byte (the final NUL).  */
  T (9, "0123", a + r, a);           /* { dg-warning "accessing 5 bytes at offsets \\\[2, 5] and 0 overlaps between 1 and 3 bytes at offset \\\[2, 4]" "strcpy" } */

  /* With a 10-byte buffer it's possible to copy all 5 bytes without
     overlap at (a + 5).  Copying at offsets 2 through 4 overflows
     between 3 and 1 bytes, respectively.  */
  T (10, "0123", a + r, a);          /* { dg-warning "accessing 5 bytes at offsets \\\[2, 5] and 0 may overlap up to 3 bytes at offset \\\[4, 2]" "strcpy" } */


  r  = SR (3, 4);
  T (8, "01",  a + r, a);
  T (8, "012", a + r, a);            /* { dg-warning "accessing 4 bytes at offsets \\\[3, 4] and 0 may overlap 1 byte at offset 3" "strcpy" } */

  /* The highest offset to which to copy without overflowing the 8-byte
     destination is 3 and that overlaps 2 bytes.  */
  T (8, "0123", a + r, a);           /* { dg-warning "accessing 5 bytes at offsets \\\[3, 4] and 0 overlaps 2 bytes at offset 3" "strcpy" } */

  /* With a 9-byte destination the highest offset is 4 and that still
     overlaps 1 byte (the final NUL).  */
  T (9, "0123", a + r, a);           /* { dg-warning "accessing 5 bytes at offsets \\\[3, 4] and 0 overlaps between 1 and 2 bytes at offset \\\[3, 4]" "strcpy" } */

  /* With a 10-byte buffer it's possible to copy all 5 bytes without
     overlap at (a + 5).  Copying at offsets 2 through 4 overflows
     between 3 and 1 bytes, respectively.  */
  T (10, "0123", a + r, a);          /* { dg-warning "accessing 5 bytes at offsets \\\[3, 4] and 0 overlaps between 1 and 2 bytes at offset \\\[3, 4]" "strcpy" } */

  T (8, "01",     a, a + r);
  T (8, "012",    a, a + r);
  T (8, "0123",   a, a + r);
  T (8, "01234",  a, a + r);

  /* With the smaller offset of 3 the final NUL definitely overlaps
     the '4' at a[3], but with the larger offset of 4 there is no
     overlap, so the warning is a "may overlap" and the size of
     the overlap is 1 byte.  */
  T (8, "012345", a, a + r);         /* { dg-warning "accessing between 3 and 4 bytes at offsets 0 and \\\[3, 4] may overlap 1 byte at offset 3" "strcpy" } */
  T (8, "0123456", a, a + r);        /* { dg-warning "accessing between 4 and 5 bytes at offsets 0 and \\\[3, 4] may overlap up to 2 bytes at offset 3" "strcpy" } */

  r = SR (3, DIFF_MAX - 3);
  T (8, "01",  a + r, a);
  T (8, "012", a + r, a);            /* { dg-warning "accessing 4 bytes at offsets \\\[3, \[0-9\]+] and 0 may overlap 1 byte at offset 3" "strcpy" } */

  r = SR (DIFF_MAX - 2, DIFF_MAX - 1);
  T (8, "012", a + r, a);            /* { dg-warning "accessing 4 bytes at offsets \\\[\[0-9\]+, \[0-9\]+] and 0 overlaps" "strcpy" } */

  /* Exercise the full range of ptrdiff_t.  */
  r = signed_value ();

  /* The overlap in the cases below isn't inevitable but it is diagnosed
     because it is possible and so the code is considered unsafe.  */
  T (8, "", a, a + r);               /* { dg-warning "accessing 1 byte may overlap 1 byte" "strcpy" } */
  T (8, "0", a + r, a);              /* { dg-warning "accessing 2 bytes may overlap up to 2 bytes" "strcpy" } */
  T (8, "012", a + r, a);            /* { dg-warning "accessing 4 bytes may overlap up to 4 bytes" "strcpy" } */

  T (8, "", a, a + r);               /* { dg-warning "accessing 1 byte may overlap" "strcpy" } */
  T (8, "0", a, a + r);              /* { dg-warning "accessing between 0 and 2 bytes may overlap up to 2 bytes" "strcpy" } */
  T (8, "012", a, a + r);            /* { dg-warning "accessing between 0 and 4 bytes may overlap up to 4 bytes" "strcpy" } */
}

/* Exercise strcpy with destination and/or source of unknown lengthu.  */

void test_strcpy_var (char *d, const char *s)
{
#undef T
#define T(dst, src) do {                        \
    if (!LINE || LINE == __LINE__) {                    \
      char *pd = (dst);                                 \
      const char *ps = (src);                           \
      strcpy (pd, ps);                                  \
      sink (pd, ps);                                    \
    }                                                   \
  } while (0)

  T (d, s);

  T (d, &d[0]);                   /* { dg-warning "source argument is the same as destination" "strcpy" } */
  T (&d[0], d);                   /* { dg-warning "source argument is the same as destination" "strcpy" } */

  s = d;
  T (d, s);                       /* { dg-warning "source argument is the same as destination" "strcpy" } */

  /* The following overlaps if *s is not nul.  It arguably should be
     diagnosed.  */
  T (d, d + 1);

  /* The following overlaps if strlen (d) is greater than 1.  Like
     the above, it possibly should be diagnosed too.  */
  int r = SR (2, 3);
  T (d, d + r);

  /* The following overlaps only if strlen (s + n) >= n so it's not
     diagnosed.  */
  s = d + signed_value ();
  T (d, s);
}

/* Exercise strncpy with constant or known arguments.  */

void test_strncpy_cst (void)
{
#undef T
#define T(init, dst, src, size) do {                    \
    if (!LINE || LINE == __LINE__) {                    \
      char a[9] = init;                                 \
      char *pd = (dst);                                 \
      const char *ps = (src);                           \
      strncpy (pd, ps, (size));                         \
      sink (a, pd, ps);                                 \
    }                                                   \
  } while (0)

  T ("012", a, a, 0);
  T ("012", a, a, 1);             /* { dg-warning "source argument is the same as destination " "strncpy" } */

  T ("012", a, a + 1, 1);
  T ("012", a, a + 1, 2);         /* { dg-warning "accessing 2 bytes at offsets 0 and 1 overlaps 1 byte at offset 1" "strncpy" } */
  T ("012", a, a + 1, 3);         /* { dg-warning "accessing 3 bytes at offsets 0 and 1 overlaps 2 bytes at offset 1" "strncpy" } */
  T ("012", a, a + 1, 4);         /* { dg-warning "accessing 4 bytes at offsets 0 and 1 overlaps 3 bytes at offset 1" "strncpy" } */
  T ("012", a, a + 1, 5);         /* { dg-warning "accessing 5 bytes at offsets 0 and 1 overlaps 3 bytes at offset 1" "strncpy" } */
  T ("012", a, a + 1, 6);         /* { dg-warning "accessing 6 bytes at offsets 0 and 1 overlaps 3 bytes at offset 1" "strncpy" } */

  T ("012", a, a + 2, 1);
  T ("012", a, a + 2, 2);
  /* The third written byte (nul) overwrites a[2].  */
  T ("012", a, a + 2, 3);         /* { dg-warning "accessing 3 bytes at offsets 0 and 2 overlaps 1 byte at offset 2" "strncpy" } */
  T ("012", a, a + 2, 4);         /* { dg-warning "accessing 4 bytes at offsets 0 and 2 overlaps 2 bytes at offset 2" "strncpy" } */
  T ("012", a, a + 2, 5);         /* { dg-warning "accessing 5 bytes at offsets 0 and 2 overlaps 2 bytes at offset 2" "strncpy" } */

  T ("0123", a, a + 2, 1);
  T ("0123", a, a + 2, 2);
  /* The terminating nul written to a[2] overwrites s[0].  */
  T ("0123", a, a + 2, 3);        /* { dg-warning "accessing 3 bytes at offsets 0 and 2 overlaps 1 byte at offset 2" "strncpy" } */
  T ("0123", a, a + 2, 4);        /* { dg-warning "accessing 4 bytes at offsets 0 and 2 overlaps 2 bytes at offset 2" "strncpy" } */
  T ("0123", a, a + 2, 5);        /* { dg-warning "accessing 5 bytes at offsets 0 and 2 overlaps 3 bytes at offset 2" "strncpy" } */
  T ("0123", a, a + 2, 6);        /* { dg-warning "accessing 6 bytes at offsets 0 and 2 overlaps 3 bytes at offset 2" "strncpy" } */

  T ("01234", a, a + 2, 1);
  T ("01234", a, a + 2, 2);
  T ("01234", a, a + 2, 3);       /* { dg-warning "accessing 3 bytes at offsets 0 and 2 overlaps 1 byte at offset 2" "strncpy" } */
  /* The '5' copied from s[2] to d[2] overwrites s[0].  */
  T ("01234", a, a + 2, 4);       /* { dg-warning "accessing 4 bytes at offsets 0 and 2 overlaps 2 bytes at offset 2" "strncpy" } */
  T ("01234", a, a + 2, 5);       /* { dg-warning "accessing 5 bytes at offsets 0 and 2 overlaps 3 bytes at offset 2" "strncpy" } */
}


/* Exercise strncpy with one or more arguments in a determinate range.  */

void test_strncpy_range (char *d, size_t n)
{
#undef T
#define T(init, dst, src, size) do {                    \
    if (!LINE || LINE == __LINE__) {                    \
      char a[9] = init;                                 \
      strncpy ((dst), (src), (size));                   \
      sink (a, (dst), (src));                           \
    }                                                   \
  } while (0)

  ptrdiff_t i;

  i = SR (0, 1);
  T ("0123", a, a + i, 0);
  T ("0123", a, a + i, 1);
  /* Offset in the range [0, i] is represented as a PHI (&a, &a + i)
     that the implementation isn't equipped to handle yet.  */
  T ("0123", a, a + i, 2);   /* { dg-warning "accessing 2 bytes at offsets 0 and \\\[0, 1] may overlap 1 byte at offset 1" "strncpy" { xfail *-*-* } } */

  i = SR (1, 5);
  T ("0123", a, a + i, 0);
  T ("0123", a, a + i, 1);
  T ("0123", a, a + i, 2);   /* { dg-warning "accessing 2 bytes at offsets 0 and \\\[1, 5] may overlap 1 byte at offset 1" "strncpy" } */
  T ("0123", a, a + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 0 and \\\[1, 5] may overlap up to 2 bytes at offset \\\[2, 1]" "strncpy" } */
  T ("0123", a, a + i, 4);   /* { dg-warning "accessing 4 bytes at offsets 0 and \\\[1, 5] may overlap up to 3 bytes at offset \\\[3, 1]" "strncpy" } */
  T ("0123", a, a + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[1, 5] may overlap up to 4 bytes at offset \\\[4, 1]" "strncpy" } */

  i = SR (2, 5);
  T ("0123", a, a + i, 0);
  T ("0123", a, a + i, 1);
  T ("0123", a, a + i, 2);
  T ("0123", a, a + i, 3);   /* { dg-warning "accessing 3 bytes at offsets 0 and \\\[2, 5] may overlap 1 byte at offset 2" "strncpy" } */
  T ("0123", a, a + i, 4);   /* { dg-warning "accessing 4 bytes at offsets 0 and \\\[2, 5] may overlap up to 2 bytes at offset \\\[3, 2]" "strncpy" } */
  T ("0123", a, a + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[2, 5] may overlap up to 3 bytes at offset \\\[4, 2]" "strncpy" } */
  T ("0123", a, a + i, 6);   /* { dg-warning "accessing 6 bytes at offsets 0 and \\\[2, 5] may overlap up to 3 bytes at offset \\\[4, 2]" "strncpy" } */

  i = SR (3, 5);
  T ("0123", a, a + i, 0);
  T ("0123", a, a + i, 1);
  T ("0123", a, a + i, 2);
  T ("0123", a, a + i, 3);
  T ("0123", a, a + i, 4);   /* { dg-warning "accessing 4 bytes at offsets 0 and \\\[3, 5] may overlap 1 byte at offset 3" "strncpy" } */
  T ("0123", a, a + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[3, 5] may overlap up to 2 bytes at offset \\\[4, 3]" "strncpy" } */
  T ("0123", a, a + i, 6);   /* { dg-warning "accessing 6 bytes at offsets 0 and \\\[3, 5] may overlap up to 2 bytes at offset \\\[4, 3]" "strncpy" } */

  i = SR (4, 5);
  T ("0123", a, a + i, 0);
  T ("0123", a, a + i, 1);
  T ("0123", a, a + i, 2);
  T ("0123", a, a + i, 3);
  T ("0123", a, a + i, 4);
  T ("0123", a, a + i, 5);   /* { dg-warning "accessing 5 bytes at offsets 0 and \\\[4, 5] may overlap 1 byte at offset 4" "strncpy" } */
  T ("0123", a, a + i, 6);   /* { dg-warning "accessing 6 bytes at offsets 0 and \\\[4, 5] may overlap 1 byte at offset 4" "strncpy" } */

  /* Verify offset and size both in some range.  The strncpy checking
     is more strict than that of memcpy and triggers even when the
     overlap is possible but not inevitable.  The following overlaps
     like so ('*' denotes the terminating NUL, '.' the appended NUL
     that's not copied from the source):
        a:        01234567*  (also indicates offset)
        i = 4:    4567       none
                  4567*      overlaps 1 at offset 4
                  4567*.     overlaps 2 at offset 4
        i = 5:    567*       none
                  567*.      none
                  567*..     overlaps 1 at offset 5  */
  T ("01234567", a, a + i, UR (4, 6));   /* { dg-warning "accessing between 4 and 6 bytes at offsets 0 and \\\[4, 5] may overlap up to 2 bytes at offset \\\[5, 4]" "strncpy" } */

  /* Ditto for objects of unknown sizes.  */
  T ("01234567", d, d + i, UR (4, 6));  /* { dg-warning "accessing between 4 and 6 bytes at offsets 0 and \\\[4, 5] may overlap up to 2 bytes at offset \\\[5, 4]" "strncpy" } */

  T ("01234567", a, a + i, UR (6, 7));  /* { dg-warning "accessing between 6 and 7 bytes at offsets 0 and \\\[4, 5] overlaps between 1 and 3 bytes at offset \\\[4, 5]" "strncpy" } */

  /* The following overlaps except in the unlikely case that value ()
     is zero, so it's diagnosed.  */
  T ("012", a, a, n);             /* { dg-warning "source argument is the same as destination " "strncpy" } */
}


/* Exercise strncpy with destination and source of unknown length.  */

void test_strncpy_var (char *d, const char *s, size_t n)
{
#undef T
#define T(dst, src, size) do {                  \
    if (!LINE || LINE == __LINE__) {            \
      char *pd = (dst);                         \
      const char *ps = (src);                   \
      strncpy (pd, ps, (size));                 \
      sink (pd, ps);                            \
    }                                           \
  } while (0)

  T (d, s, 1);
  T (d, s, n);

  T (d, d, 1);                    /* { dg-warning "\\\[-Wrestrict" "strncpy" } */
  T (d, d, n);                    /* { dg-warning "\\\[-Wrestrict" "strncpy" } */

  T (d,     d + 1, 1);
  T (d,     d + 1, 2);            /* { dg-warning "\\\[-Wrestrict" "strncpy" } */
  T (d + 1, d,     1);
  T (d + 1, d,     2);            /* { dg-warning "\\\[-Wrestrict" "strncpy" } */
}

struct MemberArrays
{
  char a[7];
  char b[8];
  char c[9];
};

void test_strncpy_strcpy_var (struct MemberArrays *ar, const char *s)
{
  /* The following is safe and should not trigger a warning.  */
  strncpy (ar->b, s, sizeof ar->b - 1);
  ar->b[sizeof ar->b - 1] = '\0';
  strcpy (ar->a, ar->b);
  sink (ar);

  /* The following is not as safe (it might overflow ar->a) but there
     is no overlap so it also shouldn't trigger -Wrestrict.  */
  strncpy (ar->c, s, sizeof ar->c - 1);
  ar->c[sizeof ar->c - 1] = '\0';
  strcpy (ar->a, ar->c);
  sink (ar);
}