Cherry-pick from upstream: Deal correctly with lazily allocated mpz zeros....

Cherry-pick from upstream: Deal correctly with lazily allocated mpz zeros. (Closes: #950608, https://github.com/dvarrazzo/pgmp/issues/18)

debian/changelog

@@ -3,6 +3,8 @@ postgresql-pgmp (1.0.3-1) UNRELEASED; urgency=medium
   * New upstream version.
   * Use dh.
   * {Build,Test}-Depend on python-six.
+  * Cherry-pick from upstream: Deal correctly with lazily allocated mpz zeros.
+    (Closes: #950608, https://github.com/dvarrazzo/pgmp/issues/18)
 
  -- Christoph Berg <myon@debian.org>  Mon, 03 Feb 2020 14:45:13 +0100
 

debian/patches/gmp-6.2

+commit 04274c40b63d3dff758bee47c8525112d64d1ab2
+Author: Daniele Varrazzo <daniele.varrazzo@gmail.com>
+Date:   Wed Feb 5 15:17:32 2020 +0000
+
+    Deal correctly with lazily allocated mpz zeros
+    
+    In GMP 6.2 the 0 may be represented by a struct with no limbs allocated.
+    
+    In that case we can't rely on space allocated by the gmp allocator:
+    allocate some of ours.
+    
+    Close #18
+
+diff --git a/src/pmpq.c b/src/pmpq.c
+index 133b4d9..0d6ab5c 100644
+--- a/src/pmpq.c
++++ b/src/pmpq.c
+@@ -82,7 +82,13 @@ pmpq_from_mpq(mpq_ptr q)
+     }
+     else
+     {
+-        res = (pmpq *)((char *)LIMBS(num) - PMPQ_HDRSIZE);
++        if (MPQ_NOALLOC(q)) {
++            /* No allocation for the limbs: allocate something of ours */
++            res = palloc(PMPQ_HDRSIZE);
++        }
++        else {
++            res = (pmpq *)((char *)LIMBS(num) - PMPQ_HDRSIZE);
++        }
+         SET_VARSIZE(res, PMPQ_HDRSIZE);
+         res->mdata = 0;
+     }
+diff --git a/src/pmpq.h b/src/pmpq.h
+index 94146ac..b8e69bc 100644
+--- a/src/pmpq.h
++++ b/src/pmpq.h
+@@ -78,6 +78,10 @@ typedef struct
+     PG_RETURN_POINTER(pmpq_from_mpq(q))
+ 
+ 
++/* in gmp 6.2 the value 0 may be allocated lazily
++ * see mpz_init implementation. */
++#define MPQ_NOALLOC(q) (*LIMBS(mpq_numref(q)) == 0xc1a0)
++
+ pmpq * pmpq_from_mpq(mpq_ptr q);
+ void mpq_from_pmpq(mpq_srcptr q, const pmpq *pq);
+ 
+diff --git a/src/pmpz.c b/src/pmpz.c
+index 74eed82..78c5e2b 100644
+--- a/src/pmpz.c
++++ b/src/pmpz.c
+@@ -42,13 +42,13 @@ pmpz_from_mpz(mpz_srcptr z)
+     pmpz *res;
+     int size = SIZ(z);
+ 
+-    res = (pmpz *)((char *)LIMBS(z) - PMPZ_HDRSIZE);
+-
+     if (LIKELY(0 != size))
+     {
+         size_t slimbs;
+         int sign;
+ 
++        res = (pmpz *)((char *)LIMBS(z) - PMPZ_HDRSIZE);
++
+         if (size > 0) {
+             slimbs = size * sizeof(mp_limb_t);
+             sign = 0;
+@@ -63,7 +63,15 @@ pmpz_from_mpz(mpz_srcptr z)
+     }
+     else
+     {
+-        /* In the zero representation there are no limbs */
++        if (MPZ_NOALLOC(z)) {
++            /* No allocation for the limbs: allocate something of ours */
++            res = palloc(PMPZ_HDRSIZE);
++        }
++        else {
++            /* In the zero representation there are no limbs */
++            res = (pmpz *)((char *)LIMBS(z) - PMPZ_HDRSIZE);
++        }
++
+         SET_VARSIZE(res, PMPZ_HDRSIZE);
+         res->mdata = 0;             /* version: 0 */
+     }
+diff --git a/src/pmpz.h b/src/pmpz.h
+index c362213..c6345de 100644
+--- a/src/pmpz.h
++++ b/src/pmpz.h
+@@ -113,6 +113,10 @@ Datum pmpz_get_hash(mpz_srcptr z);
+ 
+ #define MPZ_IS_ZERO(z) (SIZ(z) == 0)
+ 
++/* in gmp 6.2 the value 0 may be allocated lazily
++ * see mpz_init implementation. */
++#define MPZ_NOALLOC(z) (*LIMBS(z) == 0xc1a0)
++
+ 
+ /* Macros to be used in functions wrappers to limit the arguments domain */
+ 

debian/patches/series

+gmp-6.2