From 2fa60c719f9678d4507fc3d4a12a148af399de4e Mon Sep 17 00:00:00 2001
From: Nathaniel Filardo <nwf20@cl.cam.ac.uk>
Date: Mon, 15 Jul 2019 16:14:36 +0100
Subject: [PATCH] POISON only integer pointers

For architectures that can't manipulate pointers like integers, don't
try XORing them like this.  It's not ideal -- perhaps we should have
"else" branches to these tests.
---
 src/mem/metaslab.h | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/mem/metaslab.h b/src/mem/metaslab.h
index 0f959cb..6a87c89 100644
--- a/src/mem/metaslab.h
+++ b/src/mem/metaslab.h
@@ -109,11 +109,12 @@ namespace snmalloc
     /// simple corruptions.
     static SNMALLOC_FAST_PATH void store_next(void* p, void* head)
     {
-#ifndef CHECK_CLIENT
       *static_cast<void**>(p) = head;
-#else
-      *static_cast<void**>(p) = head;
-      *(static_cast<uintptr_t*>(p) + 1) = address_cast(head) ^ POISON;
+#if defined(CHECK_CLIENT)
+      if constexpr (aal_supports<IntegerPointers>)
+      {
+        *(static_cast<uintptr_t*>(p) + 1) = address_cast(head) ^ POISON;
+      }
 #endif
     }
 
@@ -121,11 +122,14 @@ namespace snmalloc
     /// In Debug checks for simple corruptions.
     static SNMALLOC_FAST_PATH void* follow_next(void* node)
     {
-#ifdef CHECK_CLIENT
-      uintptr_t next = *static_cast<uintptr_t*>(node);
-      uintptr_t chk = *(static_cast<uintptr_t*>(node) + 1);
-      if ((next ^ chk) != POISON)
-        error("Detected memory corruption.  Use-after-free.");
+#if defined(CHECK_CLIENT)
+      if constexpr (aal_supports<IntegerPointers>)
+      {
+        uintptr_t next = *static_cast<uintptr_t*>(node);
+        uintptr_t chk = *(static_cast<uintptr_t*>(node) + 1);
+        if ((next ^ chk) != POISON)
+          error("Detected memory corruption.  Use-after-free.");
+      }
 #endif
       return *static_cast<void**>(node);
     }