From: Simon Marchi <simon.marchi@polymtl.ca>
To: gdb-patches@sourceware.org
Cc: tom@tromey.com, Simon Marchi <simon.marchi@polymtl.ca>
Subject: [PATCH 2/2] darwin: Don't use sbrk
Date: Wed, 04 Jul 2018 04:31:00 -0000 [thread overview]
Message-ID: <20180704043033.29212-2-simon.marchi@polymtl.ca> (raw)
In-Reply-To: <20180704043033.29212-1-simon.marchi@polymtl.ca>
This patch gets rid of this warning on macOS:
CXX main.o
/Users/simark/src/binutils-gdb/gdb/main.c:492:27: error: 'sbrk' is deprecated [-Werror,-Wdeprecated-declarations]
lim_at_start = (char *) sbrk (0);
^
/usr/include/unistd.h:585:1: note: 'sbrk' has been explicitly marked deprecated here
__deprecated __WATCHOS_PROHIBITED __TVOS_PROHIBITED
^
/usr/include/sys/cdefs.h:176:37: note: expanded from macro '__deprecated'
#define __deprecated __attribute__((deprecated))
^
sbrk on macOS is not useful for our purposes, since sbrk(0) always
returns the same value. From what I read, brk/sbrk on macOS is just an
emulation, it always returns a pointer in a 4MB section reserved for
that.
So instead of letting users use "maint set per-command space on" and
print silly results, I think we should just disable that feature for
this platform (as we do for platforms that don't have sbrk).
I defined a HAVE_USEFUL_SBRK macro and used that instead of HAVE_SBRK.
gdb/ChangeLog:
* common/common-defs.h (HAVE_USEFUL_SBRK): Define.
* main.c: Use HAVE_USEFUL_SBRK instead of HAVE_SBRK.
* maint.c: Likewise.
* top.c: Likewise.
---
gdb/common/common-defs.h | 4 ++++
gdb/main.c | 2 +-
gdb/maint.c | 4 ++--
gdb/top.c | 2 +-
4 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/gdb/common/common-defs.h b/gdb/common/common-defs.h
index eb0ec214926c..8209e13943d7 100644
--- a/gdb/common/common-defs.h
+++ b/gdb/common/common-defs.h
@@ -105,4 +105,8 @@
/* String containing the current directory (what getwd would return). */
extern char *current_directory;
+#if defined (HAVE_SBRK) && !__APPLE__
+#define HAVE_USEFUL_SBRK 1
+#endif
+
#endif /* COMMON_DEFS_H */
diff --git a/gdb/main.c b/gdb/main.c
index 9694af242699..e925128a4263 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -487,7 +487,7 @@ captured_main_1 (struct captured_main_args *context)
int save_auto_load;
struct objfile *objfile;
-#ifdef HAVE_SBRK
+#ifdef HAVE_USEFUL_SBRK
/* Set this before constructing scoped_command_stats. */
lim_at_start = (char *) sbrk (0);
#endif
diff --git a/gdb/maint.c b/gdb/maint.c
index a8a1fcbc2996..5d4701cfacca 100644
--- a/gdb/maint.c
+++ b/gdb/maint.c
@@ -828,7 +828,7 @@ scoped_command_stats::~scoped_command_stats ()
if (m_space_enabled && per_command_space)
{
-#ifdef HAVE_SBRK
+#ifdef HAVE_USEFUL_SBRK
char *lim = (char *) sbrk (0);
long space_now = lim - lim_at_start;
@@ -866,7 +866,7 @@ scoped_command_stats::scoped_command_stats (bool msg_type)
{
if (!m_msg_type || per_command_space)
{
-#ifdef HAVE_SBRK
+#ifdef HAVE_USEFUL_SBRK
char *lim = (char *) sbrk (0);
m_start_space = lim - lim_at_start;
m_space_enabled = 1;
diff --git a/gdb/top.c b/gdb/top.c
index fdef3e0d0bf2..de1a335e40a4 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -171,7 +171,7 @@ int remote_timeout = 2;
int remote_debug = 0;
/* Sbrk location on entry to main. Used for statistics only. */
-#ifdef HAVE_SBRK
+#ifdef HAVE_USEFUL_SBRK
char *lim_at_start;
#endif
--
2.17.1
next prev parent reply other threads:[~2018-07-04 4:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-04 4:31 [PATCH 1/2] darwin: Silence syscall deprecated declaration warning Simon Marchi
2018-07-04 4:31 ` Simon Marchi [this message]
2018-07-04 10:49 ` [PATCH 2/2] darwin: Don't use sbrk Pedro Alves
2018-07-04 16:41 ` Simon Marchi
2018-07-04 10:31 ` [PATCH 1/2] darwin: Silence syscall deprecated declaration warning Pedro Alves
2018-07-04 16:39 ` Simon Marchi
2018-07-05 16:12 ` Pedro Alves
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