On Monday, 26 November 2012 at 19:14:09 UTC, Joseph Rushton
Wakeling wrote:
On 11/26/2012 04:07 PM, Joseph Rushton Wakeling wrote:
Ok, now I really want to know why it crashes. I've narrowed it
down to an example below. It seems there is a problem with
RefCounted being used as value in a map.
At the bottom I've included some dissassembly. If anyone can shed
light and maybe suggest techniques for debugging that would be
great. The issue is the assignment 'map[1] = Foo()' is calling
into 'void opAssign(typeof(this) rhs)' of RefCounted!int. But
upon entry the this pointer looks reasonable but the store is
bogus:
(gdb) p this
$28 = (struct std.typecons.RefCounted!(int).RefCounted *)
0x7fffffffd790
(gdb) p *this
$29 = {RefCounted = {_store = 0xffffffffffffffff}}
The rhs of the opAssign looks good:
p rhs
$30 = {RefCounted = {_store = 0x0}}
Any suggestions/pointers/ideas welcome.
Thanks
Dan
-------------------------
import std.typecons;
import std.stdio;
alias RefCounted!(int) Foo;
Foo[int] map;
unittest {
map[1] = Foo();
}
--------------------
Dump of assembler code for function _D3lnk11__unittest1FZv:
0x000000000044367c <+0>: push %rbp
0x000000000044367d <+1>: mov %rsp,%rbp
0x0000000000443680 <+4>: sub $0x38,%rsp
0x0000000000443684 <+8>: push %rbx
0x0000000000443685 <+9>: movl $0x1,-0x30(%rbp)
0x000000000044368c <+16>: lea -0x30(%rbp),%rcx
0x0000000000443690 <+20>: movabs $0x8,%rdx
0x000000000044369a <+30>: movabs $0x481340,%rsi
0x00000000004436a4 <+40>: mov %fs:0x0,%rdi
0x00000000004436ad <+49>: add 0x2478d4(%rip),%rdi #
0x68af88
0x00000000004436b4 <+56>: callq 0x44df08 <_aaGetX>
0x00000000004436b9 <+61>: mov %rax,-0x28(%rbp)
0x00000000004436bd <+65>: test %rax,%rax
0x00000000004436c0 <+68>: jne 0x4436cc
<_D3lnk11__unittest1FZv+80>
0x00000000004436c2 <+70>: mov $0x8,%edi
0x00000000004436c7 <+75>: callq 0x44c50c <_D3lnk7__arrayZ>
0x00000000004436cc <+80>: sub $0x8,%rsp
0x00000000004436d0 <+84>: xor %rax,%rax
0x00000000004436d3 <+87>: mov %rax,-0x10(%rbp)
0x00000000004436d7 <+91>: mov %rax,-0x18(%rbp)
0x00000000004436db <+95>: lea -0x18(%rbp),%rbx
0x00000000004436df <+99>: pushq (%rbx)
0x00000000004436e1 <+101>: lea -0x20(%rbp),%rdi
0x00000000004436e5 <+105>: callq 0x443d60
<_D3std8typecons18__T10RefCountedTiZ10RefCounted8opAssignMFS3std8typecons18__T10RefCountedTiZ10RefCountedZv>
=> 0x00000000004436ea <+110>: add $0x10,%rsp
0x00000000004436ee <+114>: lea -0x20(%rbp),%rsi
0x00000000004436f2 <+118>: mov -0x28(%rbp),%rdi
0x00000000004436f6 <+122>: mov %rdi,-0x38(%rbp)
0x00000000004436fa <+126>: movsq %ds:(%rsi),%es:(%rdi)
0x00000000004436fc <+128>: mov -0x38(%rbp),%rax
0x0000000000443700 <+132>: mov %rax,-0x8(%rbp)
0x0000000000443704 <+136>: callq 0x44370b
<_D3lnk11__unittest1FZv+143>
0x0000000000443709 <+141>: jmp 0x443715
<_D3lnk11__unittest1FZv+153>
0x000000000044370b <+143>: lea -0x20(%rbp),%rdi
0x000000000044370f <+147>: callq 0x443ce4
<_D3std8typecons18__T10RefCountedTiZ10RefCounted6__dtorMFZv>
0x0000000000443714 <+152>: retq
0x0000000000443715 <+153>: pop %rbx
0x0000000000443716 <+154>: leaveq
0x0000000000443717 <+155>: retq
End of assembler dump.
