From 4d8ebeddc56f49aa0b4d7cec506cab14320e1bb4 Mon Sep 17 00:00:00 2001 From: Juergen Werner 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 --- 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)