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- From 4d8ebeddc56f49aa0b4d7cec506cab14320e1bb4 Mon Sep 17 00:00:00 2001
- From: Juergen Werner <juergen@opensourcerouting.org>
- Date: Tue, 1 Oct 2019 14:24:20 +0200
- Subject: [PATCH] lib: Revert usage of asm-code in MTYPE definitions
-
- The asm-code was interpreted inconsistently for different platforms.
- In particular for AArch64 this caused UB, if multiple static MTYPEs
- where defined in one file. All static MTYPE_* could point to the same
- memory location (namely the first defined MTYPE) OR to their respective
- (correct) locations depending on the context of their usage.
-
- Signed-off-by: Juergen Werner <juergen@opensourcerouting.org>
- ---
- doc/developer/memtypes.rst | 2 +-
- lib/memory.h | 16 ++++------------
- 2 files changed, 5 insertions(+), 13 deletions(-)
-
- diff --git a/doc/developer/memtypes.rst b/doc/developer/memtypes.rst
- index 13f6b43bbf..1af871963a 100644
- --- a/doc/developer/memtypes.rst
- +++ b/doc/developer/memtypes.rst
- @@ -48,7 +48,7 @@ Definition
- should be used to create these, but in some cases it is useful to pass a
- ``struct memtype *`` pointer to some helper function.
-
- - The ``MTYPE_name`` created by the macros is declared as an array, i.e.
- + The ``MTYPE_name`` created by the macros is declared as a pointer, i.e.
- a function taking a ``struct memtype *`` argument can be called with an
- ``MTYPE_name`` argument (as opposed to ``&MTYPE_name``.)
-
- diff --git a/lib/memory.h b/lib/memory.h
- index 14cd76f2f5..8de5c4c2bf 100644
- --- a/lib/memory.h
- +++ b/lib/memory.h
- @@ -101,14 +101,9 @@ struct memgroup {
- *_mg_##mname.ref = _mg_##mname.next; \
- }
-
- -
- -/* the array is a trick to make the "MTYPE_FOO" name work as a pointer without
- - * putting a & in front of it, so we can do "XMALLOC(MTYPE_FOO, ...)" instead
- - * of "XMALLOC(&MTYPE_FOO, ...)".
- - */
- #define DECLARE_MTYPE(name) \
- extern struct memtype _mt_##name; \
- - extern struct memtype MTYPE_##name[1]; \
- + extern struct memtype *const MTYPE_##name; \
- /* end */
-
- #define DEFINE_MTYPE_ATTR(group, mname, attr, desc) \
- @@ -138,17 +133,14 @@ struct memgroup {
- } \
- /* end */
-
- -/* can't quite get gcc to emit the alias correctly, so asm-alias it is :/ */
- #define DEFINE_MTYPE(group, name, desc) \
- DEFINE_MTYPE_ATTR(group, name, , desc) \
- - __asm__(".equiv MTYPE_" #name ", _mt_" #name "\n\t" \
- - ".global MTYPE_" #name "\n"); \
- + struct memtype *const MTYPE_##name = &_mt_##name; \
- /* end */
- -/* and this one's borked on clang, it drops static on aliases :/, so... asm */
- +
- #define DEFINE_MTYPE_STATIC(group, name, desc) \
- DEFINE_MTYPE_ATTR(group, name, static, desc) \
- - extern struct memtype MTYPE_##name[1]; \
- - __asm__(".equiv MTYPE_" #name ", _mt_" #name "\n"); \
- + static struct memtype *const MTYPE_##name = &_mt_##name; \
- /* end */
-
- DECLARE_MGROUP(LIB)
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