Attachment 585026 Details for Bug 821918 – Fix for scoping issue

[patch] Fix for scoping issue

pari-2.5.1-gcc47.patch (text/plain), 972 bytes, created by Paul Howarth on 2012-05-16 17:38:06 UTC

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Creator: Paul Howarth

Created: 2012-05-16 17:38:06 UTC

Size: 972 bytes

patch

obsolete

>https://bugzilla.redhat.com/show_bug.cgi?id=821918
>
>  if (k) {
>...
>    struct veccmp_s v;
>...
>    v.cmp = cmp;
>    v.k = k;
>    E = (void*)&v;
>    CMP = &veccmp;    
>  } else {
>    E = (void*)((typ(x) == t_VECSMALL)? cmp_small: cmp);
>    CMP = &cmp_nodata;
>  }
>...
>  use *E
>
>This is undefined behaviour; after the v variable goes out of scope (at } before
>else), you can't reference it any longer, even when the E pointer is still in
>scope.  It is the same bug as returning an address of an automatic variable
>from a function:
>int *foo (void) { int x = 1; return &x; }
>
>--- src/basemath/bibli2.c
>+++ src/basemath/bibli2.c
>@@ -1394,12 +1394,12 @@
>   int (*CMP)(void*,GEN,GEN);
>   int (*cmp)(GEN,GEN) = (flag & cmp_LEX)? &lexcmp: &gcmp;
>   void *E;
>+  struct veccmp_s v;
> 
>   if (flag < 0 || flag > (cmp_REV|cmp_LEX|cmp_IND|cmp_UNIQ))
>     pari_err(flagerr,"vecsort");
>   if (k) {
>     long i, j, l, lk, tx, lx;
>-    struct veccmp_s v;
>     GEN y;
> 
>     /* cf init_sort */

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Attachments on bug 821918: 584761 | 585026