From: Eric Botcazou <ebotcazou@adacore.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [patch] Fix GC issue triggered by arithmetic overflow checking
Date: Thu, 13 Oct 2016 10:16:00 -0000 [thread overview]
Message-ID: <1624828.Cq9Sk6vVoa@polaris> (raw)
In-Reply-To: <CAFiYyc2YzPFDOh-Pxmna6xWcrkguQ=1YW+uDSJPRyXHApjG-7Q@mail.gmail.com>
> Yes. But that's not the only source for DECL_UID differences. Btw,
> I see lots of FOR_EACH_HASH_TABLE_ELEMENT in var-tracking.c
> but they don't look like their outcome is supposed to be dependent on
> element ordering.
This leads to NOTE_INSN_VAR_LOCATION notes emitted in a different order, which
are then interpreted by dwarf2out_var_location. In particular:
(note 6350 6349 6351 (var_location temp (nil)) NOTE_INSN_VAR_LOCATION)
(note 6351 6350 6352 (var_location temp$low (mem/c:DI (plus:SI (reg/f:SI 30
%fp)
(const_int -112 [0xffffffffffffff90])) [10 MEM[(struct cpp_num
*)&result + 8B]+0 S8 A64])) NOTE_INSN_VAR_LOCATION)
(note 6352 6351 6353 (var_location temp$8 (nil)) NOTE_INSN_VAR_LOCATION)
[...]
(code_label 2091 6355 2092 79 912 "" [1 uses])
(note 2092 2091 5271 79 [bb 79] NOTE_INSN_BASIC_BLOCK)
is interpreted differently from:
(note 6350 6349 6351 (var_location temp (nil)) NOTE_INSN_VAR_LOCATION)
(note 6351 6350 6352 (var_location temp$8 (nil)) NOTE_INSN_VAR_LOCATION)
(note 6352 6351 6353 (var_location temp$low (mem/c:DI (plus:SI (reg/f:SI 30
%fp)
(const_int -112 [0xffffffffffffff90])) [10 MEM[(struct cpp_num
*)&result + 8B]+0 S8 A64])) NOTE_INSN_VAR_LOCATION)
[...]
(note 2092 2091 5271 79 [bb 79] NOTE_INSN_BASIC_BLOCK)
@@ -32608,6 +32608,17 @@
.uleb128 0x8
.byte 0x93 ! DW_OP_piece
.uleb128 0x8
+ .uaword .LLVL592-.LLtext0 ! Location list begin address
(*.LLLST153)
+ .uaword .LLVL597-.LLtext0 ! Location list end address
(*.LLLST153)
+ .uahalf 0x9 ! Location expression size
+ .byte 0x93 ! DW_OP_piece
+ .uleb128 0x8
+ .byte 0x8e ! DW_OP_breg30
+ .sleb128 -112
+ .byte 0x93 ! DW_OP_piece
+ .uleb128 0x8
+ .byte 0x93 ! DW_OP_piece
+ .uleb128 0x8
.uaword .LLVL695-.LLtext0 ! Location list begin address
(*.LLLST153)
.uaword .LLVL696-.LLtext0 ! Location list end address
(*.LLLST153)
.uahalf 0xe ! Location expression size
probably because the non-null location comes last in the second case.
--
Eric Botcazou
next prev parent reply other threads:[~2016-10-13 10:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-08 18:56 Eric Botcazou
2016-10-10 8:59 ` Richard Biener
2016-10-10 10:38 ` Eric Botcazou
2016-10-10 10:45 ` Richard Biener
2016-10-11 8:05 ` Eric Botcazou
2016-10-16 18:57 ` Eric Botcazou
2016-10-17 8:40 ` Richard Biener
2016-10-10 10:49 ` Richard Biener
2016-10-13 10:16 ` Eric Botcazou [this message]
2016-10-13 10:20 ` Richard Biener
2016-10-13 10:37 ` Jakub Jelinek
2016-10-13 10:59 ` Eric Botcazou
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