On Wed, 2020-07-01 at 11:57 -0600, Jeff Law wrote:
> On Wed, 2020-07-01 at 14:29 +0200, Ilya Leoshkevich via Gcc-patches
> wrote:
> > gcc/ChangeLog:
> >
> > 2020-06-30 Ilya Leoshkevich <i...@linux.ibm.com>
> >
> > * asan.c (asan_emit_stack_protection): Use CODE_LABEL_BOUNDARY.
> > * defaults.h (CODE_LABEL_BOUNDARY): New macro.
> > * doc/tm.texi: Document CODE_LABEL_BOUNDARY.
> > * doc/tm.texi.in: Likewise.
> Don't we already have the ability to set label alignments? See
> LABEL_ALIGN.
The following works with -falign-labels=2:
--- a/gcc/asan.c
+++ b/gcc/asan.c
@@ -1524,7 +1524,7 @@ asan_emit_stack_protection (rtx base, rtx pbase,
unsigned int alignb,
DECL_INITIAL (decl) = decl;
TREE_ASM_WRITTEN (decl) = 1;
TREE_ASM_WRITTEN (id) = 1;
- SET_DECL_ALIGN (decl, CODE_LABEL_BOUNDARY);
+ SET_DECL_ALIGN (decl, (1 << LABEL_ALIGN (gen_label_rtx ())) *
BITS_PER_UNIT);
emit_move_insn (mem, expand_normal (build_fold_addr_expr (decl)));
shadow_base = expand_binop (Pmode, lshr_optab, base,
gen_int_shift_amount (Pmode,
ASAN_SHADOW_SHIFT),
In order to go this way, we would need to raise `-falign-labels=`
default to 2 for s390, which is not incorrect, but would unnecessarily
clutter asm with `.align 2` before each label. So IMHO it would be
nicer to simply ask the backend "what is your target's instruction
alignment?".
