PR c/85623 - strncmp() warns about attribute 'nonstring' incorrectly in -Wstringop-overflow
gcc/ChangeLog: PR c/85623 * calls.c (maybe_warn_nonstring_arg): Use string length to set or ajust the presumed bound on an operation to avoid unnecessary warnings. gcc/testsuite/ChangeLog: PR c/85623 * c-c++-common/attr-nonstring-3.c: Adjust. * c-c++-common/attr-nonstring-4.c: Adjust. * c-c++-common/attr-nonstring-6.c: New test. From-SVN: r260541
This commit is contained in:
Martin Sebor
Martin Sebor
parent
9b56ec1111
commit
d677a8b681
6 changed files with 274 additions and 13 deletions
|
|
@ -40,6 +40,13 @@
|
|||
* config/aarch64/predicates.md (aarch64_reg_zero_or_fp_zero):
|
||||
New predicate.
|
||||
|
||||
2018-05-22 Martin Sebor <msebor@redhat.com>
|
||||
|
||||
PR c/85623
|
||||
* calls.c (maybe_warn_nonstring_arg): Use string length to set
|
||||
or ajust the presumed bound on an operation to avoid unnecessary
|
||||
warnings.
|
||||
|
||||
2018-05-22 Martin Sebor <msebor@redhat.com>
|
||||
|
||||
PR tree-optimization/85826
|
||||
|
|
|
|||
73
gcc/calls.c
73
gcc/calls.c
|
|
@ -55,6 +55,7 @@ along with GCC; see the file COPYING3. If not see
|
|||
#include "stringpool.h"
|
||||
#include "attribs.h"
|
||||
#include "builtins.h"
|
||||
#include "gimple-fold.h"
|
||||
|
||||
/* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
|
||||
#define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
|
||||
|
|
@ -1616,15 +1617,36 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
|
|||
/* The bound argument to a bounded string function like strncpy. */
|
||||
tree bound = NULL_TREE;
|
||||
|
||||
/* The range of lengths of a string argument to one of the comparison
|
||||
functions. If the length is less than the bound it is used instead. */
|
||||
tree lenrng[2] = { NULL_TREE, NULL_TREE };
|
||||
|
||||
/* It's safe to call "bounded" string functions with a non-string
|
||||
argument since the functions provide an explicit bound for this
|
||||
purpose. */
|
||||
switch (DECL_FUNCTION_CODE (fndecl))
|
||||
{
|
||||
case BUILT_IN_STPNCPY:
|
||||
case BUILT_IN_STPNCPY_CHK:
|
||||
case BUILT_IN_STRCMP:
|
||||
case BUILT_IN_STRNCMP:
|
||||
case BUILT_IN_STRNCASECMP:
|
||||
{
|
||||
/* For these, if one argument refers to one or more of a set
|
||||
of string constants or arrays of known size, determine
|
||||
the range of their known or possible lengths and use it
|
||||
conservatively as the bound for the unbounded function,
|
||||
and to adjust the range of the bound of the bounded ones. */
|
||||
unsigned stride = with_bounds ? 2 : 1;
|
||||
for (unsigned argno = 0; argno < nargs && !*lenrng; argno += stride)
|
||||
{
|
||||
tree arg = CALL_EXPR_ARG (exp, argno);
|
||||
if (!get_attr_nonstring_decl (arg))
|
||||
get_range_strlen (arg, lenrng);
|
||||
}
|
||||
}
|
||||
/* Fall through. */
|
||||
|
||||
case BUILT_IN_STPNCPY:
|
||||
case BUILT_IN_STPNCPY_CHK:
|
||||
case BUILT_IN_STRNCPY:
|
||||
case BUILT_IN_STRNCPY_CHK:
|
||||
{
|
||||
|
|
@ -1651,6 +1673,33 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
|
|||
if (bound)
|
||||
get_size_range (bound, bndrng);
|
||||
|
||||
if (*lenrng)
|
||||
{
|
||||
/* Add one for the nul. */
|
||||
lenrng[0] = const_binop (PLUS_EXPR, TREE_TYPE (lenrng[0]),
|
||||
lenrng[0], size_one_node);
|
||||
lenrng[1] = const_binop (PLUS_EXPR, TREE_TYPE (lenrng[1]),
|
||||
lenrng[1], size_one_node);
|
||||
|
||||
if (!bndrng[0])
|
||||
{
|
||||
/* Conservatively use the upper bound of the lengths for
|
||||
both the lower and the upper bound of the operation. */
|
||||
bndrng[0] = lenrng[1];
|
||||
bndrng[1] = lenrng[1];
|
||||
bound = void_type_node;
|
||||
}
|
||||
else
|
||||
{
|
||||
/* Replace the bound on the oparation with the upper bound
|
||||
of the length of the string if the latter is smaller. */
|
||||
if (tree_int_cst_lt (lenrng[1], bndrng[0]))
|
||||
bndrng[0] = lenrng[1];
|
||||
else if (tree_int_cst_lt (lenrng[1], bndrng[1]))
|
||||
bndrng[1] = lenrng[1];
|
||||
}
|
||||
}
|
||||
|
||||
/* Iterate over the built-in function's formal arguments and check
|
||||
each const char* against the actual argument. If the actual
|
||||
argument is declared attribute non-string issue a warning unless
|
||||
|
|
@ -1693,18 +1742,28 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
|
|||
|
||||
tree type = TREE_TYPE (decl);
|
||||
|
||||
/* The maximum number of array elements accessed. */
|
||||
offset_int wibnd = 0;
|
||||
if (bndrng[0])
|
||||
wibnd = wi::to_offset (bndrng[0]);
|
||||
|
||||
/* Size of the array. */
|
||||
offset_int asize = wibnd;
|
||||
|
||||
/* Determine the array size. For arrays of unknown bound and
|
||||
pointers reset BOUND to trigger the appropriate warning. */
|
||||
if (TREE_CODE (type) == ARRAY_TYPE)
|
||||
if (tree arrbnd = TYPE_DOMAIN (type))
|
||||
{
|
||||
if ((arrbnd = TYPE_MAX_VALUE (arrbnd)))
|
||||
asize = wi::to_offset (arrbnd) + 1;
|
||||
}
|
||||
{
|
||||
if (tree arrbnd = TYPE_DOMAIN (type))
|
||||
{
|
||||
if ((arrbnd = TYPE_MAX_VALUE (arrbnd)))
|
||||
asize = wi::to_offset (arrbnd) + 1;
|
||||
}
|
||||
else if (bound == void_type_node)
|
||||
bound = NULL_TREE;
|
||||
}
|
||||
else if (bound == void_type_node)
|
||||
bound = NULL_TREE;
|
||||
|
||||
location_t loc = EXPR_LOCATION (exp);
|
||||
|
||||
|
|
|
|||
|
|
@ -4,6 +4,13 @@
|
|||
* gcc.target/aarch64/ldp_stp_7.c: New.
|
||||
* gcc.target/aarch64/ldp_stp_8.c: New.
|
||||
|
||||
2018-05-22 Martin Sebor <msebor@redhat.com>
|
||||
|
||||
PR c/85623
|
||||
* c-c++-common/attr-nonstring-3.c: Adjust.
|
||||
* c-c++-common/attr-nonstring-4.c: Adjust.
|
||||
* c-c++-common/attr-nonstring-6.c: New test.
|
||||
|
||||
2018-05-22 Martin Sebor <msebor@redhat.com>
|
||||
|
||||
PR tree-optimization/85826
|
||||
|
|
|
|||
|
|
@ -47,7 +47,10 @@ char* strndup (const char*, size_t);
|
|||
|
||||
#define NONSTRING __attribute__ ((nonstring))
|
||||
|
||||
char str[4];
|
||||
/* STR needs to be bigger than ARR to trigger warnings, otherwise
|
||||
since STR must be a string, using both in a string function
|
||||
can be assumed to be safe even if ARR isn't nul-terminated. */
|
||||
char str[5];
|
||||
char arr[4] NONSTRING;
|
||||
|
||||
char *ptr;
|
||||
|
|
@ -55,7 +58,7 @@ char *parr NONSTRING;
|
|||
|
||||
struct MemArrays
|
||||
{
|
||||
char str[4];
|
||||
char str[5];
|
||||
char arr[4] NONSTRING;
|
||||
char *parr NONSTRING;
|
||||
};
|
||||
|
|
|
|||
|
|
@ -37,23 +37,23 @@ int warn_strcmp_cst_2 (void)
|
|||
|
||||
int warn_strncmp_cst_1 (void)
|
||||
{
|
||||
return strncmp ("bar", ar5, X); /* { dg-warning "argument 2 declared attribute .nonstring." } */
|
||||
return strncmp ("12345", ar5, X); /* { dg-warning "argument 2 declared attribute .nonstring." } */
|
||||
}
|
||||
|
||||
int warn_strncmp_cst_2 (void)
|
||||
{
|
||||
return strncmp (ar5, "foo", X); /* { dg-warning "argument 1 declared attribute .nonstring." } */
|
||||
return strncmp (ar5, "12345", X); /* { dg-warning "argument 1 declared attribute .nonstring." } */
|
||||
}
|
||||
|
||||
|
||||
int nowarn_strncmp_cst_1 (void)
|
||||
{
|
||||
return strncmp ("bar", ar5, N);
|
||||
return strncmp ("12345", ar5, N);
|
||||
}
|
||||
|
||||
int nowarn_strncmp_cst_2 (void)
|
||||
{
|
||||
return strncmp (ar5, "foo", N);
|
||||
return strncmp (ar5, "12345", N);
|
||||
}
|
||||
|
||||
|
||||
|
|
|
|||
185
gcc/testsuite/c-c++-common/attr-nonstring-6.c
Normal file
185
gcc/testsuite/c-c++-common/attr-nonstring-6.c
Normal file
|
|
@ -0,0 +1,185 @@
|
|||
/* PR 85623 - strncmp() warns about attribute 'nonstring' incorrectly
|
||||
in -Wstringop-overflow
|
||||
{ dg-do compile }
|
||||
{ dg-options "-O2 -Wstringop-overflow -ftrack-macro-expansion=0" } */
|
||||
|
||||
#include "../gcc.dg/range.h"
|
||||
|
||||
#if __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
|
||||
extern int strcmp (const char*, const char*);
|
||||
extern int strncmp (const char*, const char*, size_t);
|
||||
extern int strncasecmp (const char*, const char*, size_t);
|
||||
|
||||
extern size_t strspn (const char*, const char*);
|
||||
extern size_t strcspn (const char*, const char*);
|
||||
|
||||
#if __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#define S26 "0123456789abcdefghijklmnopqrstuvwxyz"
|
||||
#define S(n) (S26 + sizeof S26 - 1 - (n))
|
||||
|
||||
char __attribute__ ((nonstring)) a3[3];
|
||||
char __attribute__ ((nonstring)) a5[5];
|
||||
|
||||
void sink (int);
|
||||
|
||||
#define T(call) sink (call)
|
||||
|
||||
void test_strcmp_cst (void)
|
||||
{
|
||||
/* Verify that no warning is issued for strcmp() calls with a non-string
|
||||
array argument when the other argument is a string whose length is
|
||||
less than the size of the array. Because the function stops reading
|
||||
at the first nul character there is no chance that it will read past
|
||||
the end of the array. */
|
||||
T (strcmp (S (0), a3));
|
||||
T (strcmp (S (1), a3));
|
||||
T (strcmp (S (2), a3));
|
||||
/* The following reads a3[3]. */
|
||||
T (strcmp (S (3), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
/* The following also reads past the end of a3. */
|
||||
T (strcmp (S (9), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strcmp (a3, S (0)));
|
||||
T (strcmp (a3, S (1)));
|
||||
T (strcmp (a3, S (2)));
|
||||
T (strcmp (a3, S (3))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcmp (a3, S (9))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
|
||||
void test_strcmp_range (const char *s)
|
||||
{
|
||||
s = signed_value () < 0 ? S (0) : S (1);
|
||||
T (strcmp (a3, s));
|
||||
|
||||
s = signed_value () < 0 ? S (0) : S (2);
|
||||
T (strcmp (a3, s));
|
||||
|
||||
s = signed_value () < 0 ? S (0) : S (3);
|
||||
T (strcmp (a3, s)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
s = signed_value () < 0 ? S (1) : S (2);
|
||||
T (strcmp (a3, s));
|
||||
|
||||
s = signed_value () < 0 ? S (1) : S (3);
|
||||
T (strcmp (a3, s)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
s = signed_value () < 0 ? S (3) : S (4);
|
||||
T (strcmp (a3, s)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
|
||||
void test_strncmp_cst (void)
|
||||
{
|
||||
T (strncmp (S (0), a3, 1));
|
||||
T (strncmp (S (1), a3, 2));
|
||||
T (strncmp (S (2), a3, 3));
|
||||
T (strncmp (S (3), a3, 3));
|
||||
T (strncmp (S (3), a3, 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncmp (S (9), a3, 3));
|
||||
T (strncmp (S (9), a3, 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strncmp (S (9), a3, 5)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncmp (a3, S (0), 1));
|
||||
T (strncmp (a3, S (1), 2));
|
||||
T (strncmp (a3, S (2), 3));
|
||||
T (strncmp (a3, S (3), 3));
|
||||
T (strncmp (a3, S (3), 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncmp (a3, S (9), 3));
|
||||
T (strncmp (a3, S (9), 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strncmp (a3, S (9), 5)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
void test_strncmp_range (const char *s)
|
||||
{
|
||||
T (strncmp (a3, S (2), UR (0, 3)));
|
||||
T (strncmp (a3, S (2), UR (1, 4)));
|
||||
T (strncmp (a3, S (2), UR (2, 5)));
|
||||
T (strncmp (a3, S (2), UR (3, 6)));
|
||||
T (strncmp (a3, S (2), UR (4, 7)));
|
||||
|
||||
T (strncmp (a3, S (5), UR (0, 3)));
|
||||
T (strncmp (a3, S (5), UR (1, 4)));
|
||||
T (strncmp (a3, S (5), UR (2, 5)));
|
||||
T (strncmp (a3, S (5), UR (3, 6)));
|
||||
T (strncmp (a3, S (5), UR (4, 7))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strncmp (a3, S (5), UR (7, 9))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
s = signed_value () < 0 ? S (0) : S (1);
|
||||
T (strncmp (a3, s, UR (1, 3)));
|
||||
T (strncmp (a3, s, UR (2, 5)));
|
||||
|
||||
s = signed_value () < 0 ? S (2) : S (5);
|
||||
T (strncmp (a3, s, UR (1, 3)));
|
||||
|
||||
s = signed_value () < 0 ? S (2) : S (5);
|
||||
T (strncmp (a3, s, UR (1, 4)));
|
||||
T (strncmp (a3, s, UR (2, 5)));
|
||||
T (strncmp (a3, s, UR (3, 6)));
|
||||
T (strncmp (a3, s, UR (4, 7))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
void test_strncasecmp (void)
|
||||
{
|
||||
T (strncasecmp (S (0), a3, 1));
|
||||
T (strncasecmp (S (1), a3, 2));
|
||||
T (strncasecmp (S (2), a3, 3));
|
||||
T (strncasecmp (S (3), a3, 3));
|
||||
T (strncasecmp (S (3), a3, 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncasecmp (S (9), a3, 3));
|
||||
T (strncasecmp (S (9), a3, 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strncasecmp (S (9), a3, 5)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncasecmp (a3, S (0), 1));
|
||||
T (strncasecmp (a3, S (1), 2));
|
||||
T (strncasecmp (a3, S (2), 3));
|
||||
T (strncasecmp (a3, S (3), 3));
|
||||
T (strncasecmp (a3, S (3), 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strncasecmp (a3, S (9), 3));
|
||||
T (strncasecmp (a3, S (9), 4)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strncasecmp (a3, S (9), 5)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
void test_strspn (void)
|
||||
{
|
||||
/* strspn must traverse all characters in the second argument except
|
||||
when the first string is empty. */
|
||||
T (strspn (S (0), a3));
|
||||
T (strspn (S (1), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (S (2), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (S (3), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (S (9), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
/* Similarly, strspn must traverse all characters in the first argument
|
||||
except when the second string is empty. */
|
||||
T (strspn (a3, S (0)));
|
||||
T (strspn (a3, S (1))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (a3, S (2))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (a3, S (3))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strspn (a3, S (9))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
|
||||
void test_strcspn (void)
|
||||
{
|
||||
T (strcspn (S (0), a3));
|
||||
T (strcspn (S (1), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (S (2), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (S (3), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (S (9), a3)); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
|
||||
T (strcspn (a3, S (0))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (a3, S (1))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (a3, S (2))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (a3, S (3))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
T (strcspn (a3, S (9))); /* { dg-warning "\\\[-Wstringop-overflow" } */
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue