[pushed] slotinfo in struct dtv_slotinfo_list should be flexible array [BZ #25...
Sourceware to Gerrit sync (Code Review)
gerrit@gnutoolchain-gerrit.osci.io
Tue Nov 12 13:00:00 GMT 2019
The original change was created by Florian Weimer.
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/glibc/+/489
......................................................................
slotinfo in struct dtv_slotinfo_list should be flexible array [BZ #25097]
GCC 10 will warn about subscribing inner length zero arrays. Use a GCC
extension in csu/libc-tls.c to allocate space for the static_slotinfo
variable. Adjust nptl_db so that the type description machinery does
not attempt to determine the size of the flexible array member slotinfo.
Change-Id: I51be146a7857186a4ede0bb40b332509487bdde8
---
M csu/libc-tls.c
M nptl_db/db-symbols.h
M nptl_db/db_info.c
M nptl_db/structs.def
M nptl_db/thread_dbP.h
M sysdeps/generic/ldsodefs.h
6 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/csu/libc-tls.c b/csu/libc-tls.c
index 33d8b61..f9e5437 100644
--- a/csu/libc-tls.c
+++ b/csu/libc-tls.c
@@ -23,7 +23,7 @@
#include <unistd.h>
#include <stdio.h>
#include <sys/param.h>
-
+#include <array_length.h>
#ifdef SHARED
#error makefile bug, this file is for static only
@@ -32,17 +32,11 @@
dtv_t _dl_static_dtv[2 + TLS_SLOTINFO_SURPLUS];
-static struct
-{
- struct dtv_slotinfo_list si;
- /* The dtv_slotinfo_list data structure does not include the actual
- information since it is defined as an array of size zero. We define
- here the necessary entries. Note that it is not important whether
- there is padding or not since we will always access the information
- through the 'si' element. */
- struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
-} static_slotinfo;
-
+static struct dtv_slotinfo_list static_slotinfo =
+ {
+ /* Allocate an array of 2 + TLS_SLOTINFO_SURPLUS elements. */
+ .slotinfo = { [array_length (_dl_static_dtv) - 1] = { 0 } },
+ };
/* Highest dtv index currently needed. */
size_t _dl_tls_max_dtv_idx;
@@ -72,16 +66,16 @@
static void
init_slotinfo (void)
{
- /* Create the slotinfo list. */
- static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
- - (char *) &static_slotinfo.si.slotinfo[0])
- / sizeof static_slotinfo.si.slotinfo[0]);
- // static_slotinfo.si.next = NULL; already zero
+ /* Create the slotinfo list. Note that the type of static_slotinfo
+ has effectively a zero-length array, so we cannot use the size of
+ static_slotinfo to determine the array length. */
+ static_slotinfo.len = array_length (_dl_static_dtv);
+ /* static_slotinfo.next = NULL; -- Already zero. */
/* The slotinfo list. Will be extended by the code doing dynamic
linking. */
GL(dl_tls_max_dtv_idx) = 1;
- GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
+ GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo;
}
static void
@@ -205,8 +199,8 @@
main_map->l_tls_modid = 1;
init_slotinfo ();
- // static_slotinfo.si.slotinfo[1].gen = 0; already zero
- static_slotinfo.si.slotinfo[1].map = main_map;
+ /* static_slotinfo.slotinfo[1].gen = 0; -- Already zero. */
+ static_slotinfo.slotinfo[1].map = main_map;
memsz = roundup (memsz, align ?: 1);
diff --git a/nptl_db/db-symbols.h b/nptl_db/db-symbols.h
index 8b078b0..7c53d80 100644
--- a/nptl_db/db-symbols.h
+++ b/nptl_db/db-symbols.h
@@ -25,6 +25,7 @@
DB_LOOKUP_NAME (SYM_SIZEOF_##type, _thread_db_sizeof_##type)
#define DB_STRUCT_FIELD(type, field) \
DB_LOOKUP_NAME (SYM_##type##_FIELD_##field, _thread_db_##type##_##field)
+#define DB_STRUCT_FLEXIBLE_ARRAY(type, field) DB_STRUCT_FIELD (type, field)
#define DB_SYMBOL(name) \
DB_LOOKUP_NAME (SYM_##name, name)
#define DB_FUNCTION(name) \
@@ -36,6 +37,8 @@
# include "structs.def"
# undef DB_STRUCT
+# undef DB_STRUCT_FIELD
+# undef DB_STRUCT_FLEXIBLE_ARRAY
# undef DB_FUNCTION
# undef DB_SYMBOL
# undef DB_VARIABLE
diff --git a/nptl_db/db_info.c b/nptl_db/db_info.c
index af7f754..40efe1a 100644
--- a/nptl_db/db_info.c
+++ b/nptl_db/db_info.c
@@ -56,6 +56,9 @@
DB_DEFINE_DESC (name, \
8 * sizeof (obj)[0], sizeof (obj) / sizeof (obj)[0], \
offset);
+/* Flexible arrays do not have a length that can be determined. */
+#define FLEXIBLE_ARRAY_DESC(name, offset, obj) \
+ DB_DEFINE_DESC (name, 8 * sizeof (obj)[0], 0, offset);
#if TLS_TCB_AT_TP
# define dtvp header.dtv
@@ -77,6 +80,9 @@
#define DB_STRUCT_ARRAY_FIELD(type, field) \
ARRAY_DESC (_thread_db_##type##_##field, \
offsetof (type, field), ((type *) 0)->field)
+#define DB_STRUCT_FLEXIBLE_ARRAY(type, field) \
+ FLEXIBLE_ARRAY_DESC (_thread_db_##type##_##field, \
+ offsetof (type, field), ((type *) 0)->field)
#define DB_VARIABLE(name) DESC (_thread_db_##name, 0, name)
#define DB_ARRAY_VARIABLE(name) ARRAY_DESC (_thread_db_##name, 0, name)
#define DB_SYMBOL(name) /* Nothing. */
diff --git a/nptl_db/structs.def b/nptl_db/structs.def
index f834d1d..a3aa71a 100644
--- a/nptl_db/structs.def
+++ b/nptl_db/structs.def
@@ -110,7 +110,7 @@
DB_STRUCT (dtv_slotinfo_list)
DB_STRUCT_FIELD (dtv_slotinfo_list, len)
DB_STRUCT_FIELD (dtv_slotinfo_list, next)
-DB_STRUCT_ARRAY_FIELD (dtv_slotinfo_list, slotinfo)
+DB_STRUCT_FLEXIBLE_ARRAY (dtv_slotinfo_list, slotinfo)
DB_STRUCT (dtv_slotinfo)
DB_STRUCT_FIELD (dtv_slotinfo, gen)
diff --git a/nptl_db/thread_dbP.h b/nptl_db/thread_dbP.h
index 1dbb543..cf6a2b0 100644
--- a/nptl_db/thread_dbP.h
+++ b/nptl_db/thread_dbP.h
@@ -37,12 +37,14 @@
{
# define DB_STRUCT(type) SYM_SIZEOF_##type,
# define DB_STRUCT_FIELD(type, field) SYM_##type##_FIELD_##field,
+# define DB_STRUCT_FLEXIBLE_ARRAY(type, field) DB_STRUCT_FIELD (type, field)
# define DB_SYMBOL(name) SYM_##name,
# define DB_FUNCTION(name) SYM_##name,
# define DB_VARIABLE(name) SYM_##name, SYM_DESC_##name,
# include "structs.def"
# undef DB_STRUCT
# undef DB_STRUCT_FIELD
+# undef DB_STRUCT_FLEXIBLE_ARRAY
# undef DB_SYMBOL
# undef DB_FUNCTION
# undef DB_VARIABLE
@@ -90,6 +92,7 @@
uint32_t ta_sizeof_##type;
# define DB_STRUCT_FIELD(type, field) \
db_desc_t ta_field_##type##_##field;
+# define DB_STRUCT_FLEXIBLE_ARRAY(type, field) DB_STRUCT_FIELD (type, field)
# define DB_SYMBOL(name) \
psaddr_t ta_addr_##name;
# define DB_FUNCTION(name) \
@@ -100,6 +103,7 @@
# include "structs.def"
# undef DB_STRUCT
# undef DB_STRUCT_FIELD
+# undef DB_STRUCT_FLEXIBLE_ARRAY
# undef DB_FUNCTION
# undef DB_SYMBOL
# undef DB_VARIABLE
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index f3ba13e..a6991f3 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -420,7 +420,7 @@
{
size_t gen;
struct link_map *map;
- } slotinfo[0];
+ } slotinfo[];
} *_dl_tls_dtv_slotinfo_list;
/* Number of modules in the static TLS block. */
EXTERN size_t _dl_tls_static_nelem;
--
Gerrit-Project: glibc
Gerrit-Branch: master
Gerrit-Change-Id: I51be146a7857186a4ede0bb40b332509487bdde8
Gerrit-Change-Number: 489
Gerrit-PatchSet: 4
Gerrit-Owner: Florian Weimer <fweimer@redhat.com>
Gerrit-Reviewer: Florian Weimer <fweimer@redhat.com>
Gerrit-Reviewer: Szabolcs Nagy <szabolcs.nagy@arm.com>
Gerrit-MessageType: newpatchset
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