This is the mail archive of the
gdb-prs@sourceware.org
mailing list for the GDB project.
[Bug exp/17904] New: "Cannot access memory at address 0x0" for function returning reference evaluated within EVAL_AVOID_SIDE_EFFECTS
- From: "ed at catmur dot co.uk" <sourceware-bugzilla at sourceware dot org>
- To: gdb-prs at sourceware dot org
- Date: Thu, 29 Jan 2015 18:31:41 +0000
- Subject: [Bug exp/17904] New: "Cannot access memory at address 0x0" for function returning reference evaluated within EVAL_AVOID_SIDE_EFFECTS
- Auto-submitted: auto-generated
https://sourceware.org/bugzilla/show_bug.cgi?id=17904
Bug ID: 17904
Summary: "Cannot access memory at address 0x0" for function
returning reference evaluated within
EVAL_AVOID_SIDE_EFFECTS
Product: gdb
Version: HEAD
Status: NEW
Severity: normal
Priority: P2
Component: exp
Assignee: unassigned at sourceware dot org
Reporter: ed at catmur dot co.uk
Given a function returning a reference:
int& g() { static int i; return i; }
Evaluating the function within a EVAL_AVOID_SIDE_EFFECTS context gives an
error:
(gdb) p 0 || +g()
Cannot access memory at address 0x0
A workaround is to convert the reference to a pointer and indirect it:
(gdb) p 0 || +*&g()
$1 = true
This appears to be because OP_FUNCALL with EVAL_AVOID_SIDE_EFFECTS calls
allocate_value(), which for reference types returns a value with
location.address = 0; promotion on the reference argument then calls
coerce_ref() which gives a lazy value pointing to 0x0.
I'm not sure of a fix other than going through evaluate_subexp_standard()
putting in checks for noside == EVAL_AVOID_SIDE_EFFECTS.
--
You are receiving this mail because:
You are on the CC list for the bug.