diff options
author | rsandifo <rsandifo@138bc75d-0d04-0410-961f-82ee72b054a4> | 2018-01-02 19:14:43 +0000 |
---|---|---|
committer | rsandifo <rsandifo@138bc75d-0d04-0410-961f-82ee72b054a4> | 2018-01-02 19:14:43 +0000 |
commit | d7ea903985b3a4ce3f8645d86b258cac1b3abf26 (patch) | |
tree | 9b53d3cd8885f377cf6981cd74d08f43baa4c258 /gcc/expr.c | |
parent | 0f78b37a1a502b2f2ce4ab2a8aee0d307e3785a6 (diff) | |
download | gcc-d7ea903985b3a4ce3f8645d86b258cac1b3abf26.tar.gz |
Fix REG_ARGS_SIZE handling when pushing TLS addresses
The new assert in add_args_size_note triggered for gcc.dg/tls/opt-3.c
and others on m68k. This looks like a pre-existing bug: if we pushed
a value that needs a call to something like __tls_get_addr, we ended
up with two different REG_ARGS_SIZE notes on the same instruction.
It seems to be OK for emit_single_push_insn to push something that
needs a call to __tls_get_addr:
/* We have to allow non-call_pop patterns for the case
of emit_single_push_insn of a TLS address. */
if (GET_CODE (pat) != PARALLEL)
return 0;
so I think the bug is in the way this is handled rather than the fact
that it occurs at all.
If we're pushing a value X that needs a call C to calculate, we'll
add REG_ARGS_SIZE notes to the pushes and pops for C as part of the
call sequence. Then emit_single_push_insn calls fixup_args_size_notes
on the whole push sequence (the calculation of X, including C,
and the push of X itself). This is where the double notes came from.
But emit_single_push_insn_1 adjusted stack_pointer_delta *before* the
push, so the notes added for C were relative to the situation after
the future push of X rather than before it.
Presumably this didn't matter in practice because the note added
second tended to trump the note added first. But code is allowed to
walk REG_NOTES without having to disregard secondary notes.
2018-01-02 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* expr.c (fixup_args_size_notes): Check that any existing
REG_ARGS_SIZE notes are correct, and don't try to re-add them.
(emit_single_push_insn_1): Move stack_pointer_delta adjustment to...
(emit_single_push_insn): ...here.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@256105 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/expr.c')
-rw-r--r-- | gcc/expr.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/gcc/expr.c b/gcc/expr.c index a84c02f41a9..275199982e3 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -4090,6 +4090,14 @@ fixup_args_size_notes (rtx_insn *prev, rtx_insn *last, if (!NONDEBUG_INSN_P (insn)) continue; + /* We might have existing REG_ARGS_SIZE notes, e.g. when pushing + a call argument containing a TLS address that itself requires + a call to __tls_get_addr. The handling of stack_pointer_delta + in emit_single_push_insn is supposed to ensure that any such + notes are already correct. */ + rtx note = find_reg_note (insn, REG_ARGS_SIZE, NULL_RTX); + gcc_assert (!note || known_eq (args_size, get_args_size (note))); + poly_int64 this_delta = find_args_size_adjust (insn); if (known_eq (this_delta, 0)) { @@ -4103,7 +4111,8 @@ fixup_args_size_notes (rtx_insn *prev, rtx_insn *last, if (known_eq (this_delta, HOST_WIDE_INT_MIN)) saw_unknown = true; - add_args_size_note (insn, args_size); + if (!note) + add_args_size_note (insn, args_size); if (STACK_GROWS_DOWNWARD) this_delta = -poly_uint64 (this_delta); @@ -4127,7 +4136,6 @@ emit_single_push_insn_1 (machine_mode mode, rtx x, tree type) rtx dest; enum insn_code icode; - stack_pointer_delta += PUSH_ROUNDING (GET_MODE_SIZE (mode)); /* If there is push pattern, use it. Otherwise try old way of throwing MEM representing push operation to move expander. */ icode = optab_handler (push_optab, mode); @@ -4214,6 +4222,14 @@ emit_single_push_insn (machine_mode mode, rtx x, tree type) emit_single_push_insn_1 (mode, x, type); + /* Adjust stack_pointer_delta to describe the situation after the push + we just performed. Note that we must do this after the push rather + than before the push in case calculating X needs pushes and pops of + its own (e.g. if calling __tls_get_addr). The REG_ARGS_SIZE notes + for such pushes and pops must not include the effect of the future + push of X. */ + stack_pointer_delta += PUSH_ROUNDING (GET_MODE_SIZE (mode)); + last = get_last_insn (); /* Notice the common case where we emitted exactly one insn. */ |