Commit d2f1971d authored by Paul Eggert's avatar Paul Eggert
Browse files

Port flexible array members to GCC + valgrind

These changes are needed to conform to the C standard's rule for
allocating structs containing flexible array members.  C11 says
that malloc (offsetof (struct s, m) + n) does not suffice to
allocate a struct with an n-byte tail; instead, malloc’s arg
should be rounded up to the nearest multiple of alignof (struct s).
Although this is arguably a defect in C11, gcc -O2 + valgrind
sometimes complains when this rule is violated, and when debugging
it’s better to keep valgrind happy.
For details please see the thread containing the message at:
https://gcc.gnu.org/ml/gcc-patches/2016-09/msg00416.html
* lib-src/ebrowse.c, src/alloc.c, src/image.c, src/process.c:
Include flexmember.h.
* lib-src/ebrowse.c (add_sym, add_member, make_namespace)
(register_namespace_alias):
* src/alloc.c (SDATA_SIZE, allocate_string_data):
* src/image.c (xpm_cache_color, imagemagick_create_cache):
* src/process.c (Fmake_network_process):
Use FLEXSIZEOF instead of offsetof and addition.
* src/alloc.c (SDATA_SIZE, vector_alignment):
Use FLEXALIGNOF instead of sizeof (ptrdiff_t).
* src/lisp.h (ALIGNOF_STRUCT_LISP_VECTOR):
Remove, as alloc.c can now calculate this on its own.
parent 12a7e0f8
......@@ -32,6 +32,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#define SEEK_END 2
#endif
#include <flexmember.h>
#include <min-max.h>
/* Files are read in chunks of this number of bytes. */
......@@ -582,7 +583,7 @@ add_sym (const char *name, struct sym *nested_in_class)
puts (name);
}
sym = xmalloc (offsetof (struct sym, name) + strlen (name) + 1);
sym = xmalloc (FLEXSIZEOF (struct sym, name, strlen (name) + 1));
memset (sym, 0, offsetof (struct sym, name));
strcpy (sym->name, name);
sym->namesp = scope;
......@@ -867,8 +868,8 @@ add_global_decl (char *name, char *regexp, int pos, unsigned int hash, int var,
static struct member *
add_member (struct sym *cls, char *name, int var, int sc, unsigned int hash)
{
struct member *m = xmalloc (offsetof (struct member, name)
+ strlen (name) + 1);
struct member *m = xmalloc (FLEXSIZEOF (struct member, name,
strlen (name) + 1));
struct member **list;
struct member *p;
struct member *prev;
......@@ -978,7 +979,7 @@ mark_inherited_virtual (void)
static struct sym *
make_namespace (char *name, struct sym *context)
{
struct sym *s = xmalloc (offsetof (struct sym, name) + strlen (name) + 1);
struct sym *s = xmalloc (FLEXSIZEOF (struct sym, name, strlen (name) + 1));
memset (s, 0, offsetof (struct sym, name));
strcpy (s->name, name);
s->next = all_namespaces;
......@@ -1062,7 +1063,7 @@ register_namespace_alias (char *new_name, struct link *old_name)
if (streq (new_name, al->name) && (al->namesp == current_namespace))
return;
al = xmalloc (offsetof (struct alias, name) + strlen (new_name) + 1);
al = xmalloc (FLEXSIZEOF (struct alias, name, strlen (new_name) + 1));
strcpy (al->name, new_name);
al->next = namespace_alias_table[h];
al->namesp = current_namespace;
......
......@@ -46,6 +46,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include TERM_HEADER
#endif /* HAVE_WINDOW_SYSTEM */
#include <flexmember.h>
#include <verify.h>
#include <execinfo.h> /* For backtrace. */
......@@ -1757,27 +1758,23 @@ static char const string_overrun_cookie[GC_STRING_OVERRUN_COOKIE_SIZE] =
#ifdef GC_CHECK_STRING_BYTES
#define SDATA_SIZE(NBYTES) \
((SDATA_DATA_OFFSET \
+ (NBYTES) + 1 \
+ sizeof (ptrdiff_t) - 1) \
& ~(sizeof (ptrdiff_t) - 1))
#define SDATA_SIZE(NBYTES) FLEXSIZEOF (struct sdata, data, NBYTES)
#else /* not GC_CHECK_STRING_BYTES */
/* The 'max' reserves space for the nbytes union member even when NBYTES + 1 is
less than the size of that member. The 'max' is not needed when
SDATA_DATA_OFFSET is a multiple of sizeof (ptrdiff_t), because then the
alignment code reserves enough space. */
SDATA_DATA_OFFSET is a multiple of FLEXALIGNOF (struct sdata),
because then the alignment code reserves enough space. */
#define SDATA_SIZE(NBYTES) \
((SDATA_DATA_OFFSET \
+ (SDATA_DATA_OFFSET % sizeof (ptrdiff_t) == 0 \
+ (SDATA_DATA_OFFSET % FLEXALIGNOF (struct sdata) == 0 \
? NBYTES \
: max (NBYTES, sizeof (ptrdiff_t) - 1)) \
: max (NBYTES, FLEXALIGNOF (struct sdata) - 1)) \
+ 1 \
+ sizeof (ptrdiff_t) - 1) \
& ~(sizeof (ptrdiff_t) - 1))
+ FLEXALIGNOF (struct sdata) - 1) \
& ~(FLEXALIGNOF (struct sdata) - 1))
#endif /* not GC_CHECK_STRING_BYTES */
......@@ -1997,7 +1994,7 @@ allocate_string_data (struct Lisp_String *s,
if (nbytes > LARGE_STRING_BYTES)
{
size_t size = offsetof (struct sblock, data) + needed;
size_t size = FLEXSIZEOF (struct sblock, data, needed);
#ifdef DOUG_LEA_MALLOC
if (!mmap_lisp_allowed_p ())
......@@ -2953,15 +2950,15 @@ set_next_vector (struct Lisp_Vector *v, struct Lisp_Vector *p)
enum
{
/* Alignment of struct Lisp_Vector objects. */
vector_alignment = COMMON_MULTIPLE (ALIGNOF_STRUCT_LISP_VECTOR,
GCALIGNMENT),
vector_alignment = COMMON_MULTIPLE (FLEXALIGNOF (struct Lisp_Vector),
GCALIGNMENT),
/* Vector size requests are a multiple of this. */
roundup_size = COMMON_MULTIPLE (vector_alignment, word_size)
};
/* Verify assumptions described above. */
verify ((VECTOR_BLOCK_SIZE % roundup_size) == 0);
verify (VECTOR_BLOCK_SIZE % roundup_size == 0);
verify (VECTOR_BLOCK_SIZE <= (1 << PSEUDOVECTOR_SIZE_BITS));
/* Round up X to nearest mult-of-ROUNDUP_SIZE --- use at compile time. */
......
......@@ -30,7 +30,9 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#endif
#include <setjmp.h>
#include <c-ctype.h>
#include <flexmember.h>
#include "lisp.h"
#include "frame.h"
......@@ -3347,7 +3349,7 @@ xpm_cache_color (struct frame *f, char *color_name, XColor *color, int bucket)
if (bucket < 0)
bucket = xpm_color_bucket (color_name);
nbytes = offsetof (struct xpm_cached_color, name) + strlen (color_name) + 1;
nbytes = FLEXSIZEOF (struct xpm_cached_color, name, strlen (color_name) + 1);
p = xmalloc (nbytes);
strcpy (p->name, color_name);
p->color = *color;
......@@ -8328,8 +8330,8 @@ static struct animation_cache *
imagemagick_create_cache (char *signature)
{
struct animation_cache *cache
= xmalloc (offsetof (struct animation_cache, signature)
+ strlen (signature) + 1);
= xmalloc (FLEXSIZEOF (struct animation_cache, signature,
strlen (signature) + 1));
cache->wand = 0;
cache->index = 0;
cache->next = 0;
......
......@@ -1429,13 +1429,6 @@ struct Lisp_Vector
Lisp_Object contents[FLEXIBLE_ARRAY_MEMBER];
};
/* C11 prohibits alignof (struct Lisp_Vector), so compute it manually. */
enum
{
ALIGNOF_STRUCT_LISP_VECTOR
= alignof (union { struct vectorlike_header a; Lisp_Object b; })
};
/* A boolvector is a kind of vectorlike, with contents like a string. */
struct Lisp_Bool_Vector
......
......@@ -88,6 +88,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#endif
#include <c-ctype.h>
#include <flexmember.h>
#include <sig2str.h>
#include <verify.h>
......@@ -3807,8 +3808,8 @@ usage: (make-network-process &rest ARGS) */)
struct gaicb gaicb;
struct addrinfo hints;
char str[FLEXIBLE_ARRAY_MEMBER];
} *req = xmalloc (offsetof (struct req, str)
+ hostlen + 1 + portstringlen + 1);
} *req = xmalloc (FLEXSIZEOF (struct req, str,
hostlen + 1 + portstringlen + 1));
dns_request = &req->gaicb;
dns_request->ar_name = req->str;
dns_request->ar_service = req->str + hostlen + 1;
......
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