Hi,
There's a line in array.c which confuses the Borland 5.5 compiler
optimizer into corrupting a pointer held in a register.
Use of -O2 flag with the 'free' compiler causes a SEGV in
miniruby during the bccwin32 build process.
I tried to produce a small test case for the Borland community to
comment on but without success, so I can't say if this is a known
problem or even what the problem is.
It doesn't occur anywhere else in the 183p1 source.
Fix has a much smaller impact than adding 'volatile' would have.
I don't like the code change, especially as it means the same thing
but it will be preferable to the SEGV if you can bear it.
---
* array.c (sort_2): work around SEGV caused by rare Borland 5.5
compiler bug when using optimize -O2 flag [ruby-core:5152]
=======================================================================
--- array_1_137_2_23.c Fri May 13 03:38:18 2005
+++ array_patched.c Mon Jun 06 17:35:30 2005
@@ -1584,7 +1584,7 @@ sort_2(ap, bp, data)
if ((long)a < (long)b) return -1;
return 0;
}
- if (TYPE(a) == T_STRING && TYPE(b) == T_STRING) {
+ if (TYPE(a) == T_STRING) if (TYPE(b) == T_STRING) { /* OK: && */
return rb_str_cmp(a, b);
}
=======================================================================
In case you're interested, here's the offending part of the
assembler expansion:
;
; if (TYPE(a) == T_STRING && TYPE(b) == T_STRING) {
;
; EBX = a, ESI = b ; returns EDX
; <snip>
; [ TYPE(a) ] if (a == Qundef) return T_UNDEF;
cmp ebx,6
jne short @542
mov edx,60
jmp short @543
@542:
; [ TYPE(a) ] if (SYMBOL_P(a)) return T_SYMBOL;
and ebx,255 ; <---*** VALUE 'a' in EBX corrupted ***
cmp ebx,14
jne short @544
mov edx,36
jmp short @545
@544:
; return BUILTIN_TYPE(a);
mov edx,dword ptr [ebx] ; <---*** SEGV (ebx)
and edx,63
@543:
@545:
; <snip> same for TYPE(b) }
The bug sends its apologies :-o
daz
begin 666 array_bccO2.patch
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E*B\*( ER971U<FX@<F)?<W1R7V-M<"AA+"!B*3L*(" @("!]"@``
`
end