DMD v0.101 for Linux

_After_ rebuilding libphobos.a on Linux, this code will cause a segfault:

void main()
{
char[] str;
str ~= "test"; // segfault
//str = str ~ "test"; // Ok
}

Tracing it into internal/gc/gc.d, it will cause the segfault at this line of code (dereferencing px.data is the culprit):

extern (C)
Array _d_arrayappend(Array *px, byte[] y, uint size)
{
uint cap = _gc.capacity(px.data); // segfault here

Used ar to extract and obj2asm to dump the assembler from both the newly recompiled gc.o and the as-shipped gc.o. The diff file showed differences in the generated code for the _d_arrayappend function.

as-shipped:
_d_arrayappend:
push    EBP
mov EBP,ESP
sub ESP,0Ch
push    EBX
mov EBX,8[EBP]  ; <-----------
mov EAX,_D3std2gc3_gcPS3gcx2GC
push    ESI
push    EDI
mov EDI,014h[EBP]
push    dword ptr 4[EBX]
call    near ptr _D3gcx2GC8capacityFPvZk

as-compiled:
_d_arrayappend:
push    EBP
mov EBP,ESP
sub ESP,010h
push    EBX
mov EBX,0Ch[EBP] ; <----------
mov EAX,_D3std2gc3_gcPS3gcx2GC
push    ESI
push    EDI
mov EDI,018h[EBP]
push    dword ptr 4[EBX]
call    near ptr _D3gcx2GC8capacityFPvZk

The obj2asm for the program (-O -inline -release):
_Dmain:
push    EBP
mov     EBP,ESP
sub     ESP,8
push    1
lea     EAX,-8[EBP]
mov     dword ptr -8[EBP],0
mov     dword ptr -4[EBP],0
push    dword ptr _TMP0[01Fh]
push    dword ptr _TMP0[021h]
push    EAX
call    near ptr _d_arrayappend
add     ESP,010h
mov     ESP,EBP
pop     EBP
ret

The relavant assembler for the non-release build is the same, and also causes the segfault.

The diff file is attached.

- Dave

Anything else I could provide regarding this?

Thanks,

- Dave

In article <ch8ukr$172i$1@digitaldaemon.com>, Dave says...
>
>
>DMD v0.101 for Linux
>
>_After_ rebuilding libphobos.a on Linux, this code will cause a segfault:
>
>void main()
>{
>char[] str;
>str ~= "test"; // segfault
>//str = str ~ "test"; // Ok
>}
>
>Tracing it into internal/gc/gc.d, it will cause the segfault at this line of code (dereferencing px.data is the culprit):
>
>extern (C)
>Array _d_arrayappend(Array *px, byte[] y, uint size)
>{
>uint cap = _gc.capacity(px.data); // segfault here
>
>Used ar to extract and obj2asm to dump the assembler from both the newly recompiled gc.o and the as-shipped gc.o. The diff file showed differences in the generated code for the _d_arrayappend function.
>
>as-shipped:
>_d_arrayappend:
>push    EBP
>mov EBP,ESP
>sub ESP,0Ch
>push    EBX
>mov EBX,8[EBP]  ; <-----------
>mov EAX,_D3std2gc3_gcPS3gcx2GC
>push    ESI
>push    EDI
>mov EDI,014h[EBP]
>push    dword ptr 4[EBX]
>call    near ptr _D3gcx2GC8capacityFPvZk
>
>as-compiled:
>_d_arrayappend:
>push    EBP
>mov EBP,ESP
>sub ESP,010h
>push    EBX
>mov EBX,0Ch[EBP] ; <----------
>mov EAX,_D3std2gc3_gcPS3gcx2GC
>push    ESI
>push    EDI
>mov EDI,018h[EBP]
>push    dword ptr 4[EBX]
>call    near ptr _D3gcx2GC8capacityFPvZk
>
>The obj2asm for the program (-O -inline -release):
>_Dmain:
>push    EBP
>mov     EBP,ESP
>sub     ESP,8
>push    1
>lea     EAX,-8[EBP]
>mov     dword ptr -8[EBP],0
>mov     dword ptr -4[EBP],0
>push    dword ptr _TMP0[01Fh]
>push    dword ptr _TMP0[021h]
>push    EAX
>call    near ptr _d_arrayappend
>add     ESP,010h
>mov     ESP,EBP
>pop     EBP
>ret
>
>The relavant assembler for the non-release build is the same, and also causes the segfault.
>
>The diff file is attached.
>
>- Dave
>
>
>begin 0644 sc_diff.txt
>M,3@T83$X-0T*/B`)"7AO<@E%0U@L14-8#0HQ.#5A,3@W+#$Y,0T*/B`)"6UO
>M=@E;14%872Q%0U@-"CX@"0EM;W8)-%M%05A=+$5#6`T*/B`)"6UO=@DX6T5!
>M6%TL14-8#0H^(`D);6]V"3!#:%M%05A=+$5#6`T*/B`)"6UO=@DP,3!H6T5!
>M6%TL14-8#0HW-C-C-S8Y#0H\(`D)<W5B"4534"PP0V@-"BTM+0T*/B`)"7-U
>M8@E%4U`L,#$P:`T*-S8U8S<W,0T*/"`)"6UO=@E%0E@L.%M%0E!=#0HM+2T-
>M"CX@"0EM;W8)14)8+#!#:%M%0E!=#0HW-CEC-S<U#0H\(`D);6]V"45$22PP
>M,31H6T5"4%T-"BTM+0T*/B`)"6UO=@E%1$DL,#$X:%M%0E!=#0HW-S5C-S@Q
>M#0H\(`D)861D"45#6"PP0VA;14)070T*+2TM#0H^(`D)861D"45#6"PP,3!H
>M6T5"4%T-"C<Y-&,X,#`-"CP@3#4Y.@D);6]V"3`Q-&A;14)072Q%1$D-"BTM
>M+0T*/B!,-3DZ"0EM;W8),#$X:%M%0E!=+$5$20T*-SDV8S@P,@T*/"`)"6UO
>M=@E%1%@L,#$P:%M%0E!=#0HM+2T-"CX@"0EM;W8)1418+#`Q-&A;14)070T*
>M-SDX8S@P-`T*/"`)"6UO=@E%05@L,$-H6T5"4%T-"BTM+0T*/B`)"6UO=@E%
>M05@L,#$P:%M%0E!=#0HX,#%C.#`W#0H\(`D):6UU;`E%1$DL,#$T:%M%0E!=
>M#0HM+2T-"CX@"0EI;75L"45$22PP,3AH6T5"4%T-"C@P,V,X,#D-"CP@"0EI
>M;75L"45#6"PP,31H6T5"4%T-"BTM+0T*/B`)"6EM=6P)14-8+#`Q.&A;14)0
>M70T*.#$Q83@Q.`T*/B`)"6UO=@E%4TDL.%M%0E!=#0HX,3-A.#(Q+#@R,PT*
>M/B`)"6UO=@E;15-)72Q%05@-"CX@"0EM;W8)14%8+$5320T*/B`)"6UO=@DT
>J6T5325TL1418#0HX,C$L.#(R9#@S,`T*/"`)"6YO<`T*/"`)"6YO<`T*
>`
>end

"Dave" <Dave_member@pathlink.com> wrote in message news:chnlj1$14uf$1@digitaldaemon.com...
>
> Anything else I could provide regarding this?

No, I know what's wrong. The calling conventions on linux are slightly different, and that tripped me up. It's now fixed.

In article <chvn4n$3tt$1@digitaldaemon.com>, Walter says...
>
>
>"Dave" <Dave_member@pathlink.com> wrote in message news:chnlj1$14uf$1@digitaldaemon.com...
>>
>> Anything else I could provide regarding this?
>
>No, I know what's wrong. The calling conventions on linux are slightly different, and that tripped me up. It's now fixed.
>
>

Thanks!

- Dave