From 4a0c53ba5a76ae4b1016f88ddba48eb47674c64a Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <anton@korobeynikov.info>
Date: Tue, 21 Apr 2020 15:07:32 +0300
Subject: [PATCH 1/3] Fix the prototype of malloc_size. Otherwise we'll end
 with invalid redeclaration if malloc/malloc.h is pulled on Darwin

---
 src/alloc-override.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/alloc-override.c b/src/alloc-override.c
index 0e908f42..75c7990f 100644
--- a/src/alloc-override.c
+++ b/src/alloc-override.c
@@ -165,7 +165,7 @@ extern "C" {
 
 void   cfree(void* p)                    MI_FORWARD0(mi_free, p);
 void*  reallocf(void* p, size_t newsize) MI_FORWARD2(mi_reallocf,p,newsize);
-size_t malloc_size(void* p)              MI_FORWARD1(mi_usable_size,p);
+size_t malloc_size(const void* p)        MI_FORWARD1(mi_usable_size,p);
 #if !defined(__ANDROID__)
 size_t malloc_usable_size(void *p)       MI_FORWARD1(mi_usable_size,p);
 #else

From 07d72f4fba97c698191a855fdf24efddc4387e74 Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <anton@korobeynikov.info>
Date: Tue, 21 Apr 2020 15:08:27 +0300
Subject: [PATCH 2/3] Do not forget to include malloc zone implementation in
 the static object

---
 CMakeLists.txt | 1 +
 src/static.c   | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e37b5083..d0d03991 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,6 +67,7 @@ if(MI_OVERRIDE MATCHES "ON")
       # use zone's on macOS
       message(STATUS "  Use malloc zone to override malloc (MI_OSX_ZONE=ON)")
       list(APPEND mi_sources src/alloc-override-osx.c)
+      list(APPEND mi_defines MI_OSX_ZONE=1)
       if(NOT MI_INTERPOSE MATCHES "ON")
         message(STATUS "  (enabling INTERPOSE as well since zone's require this)")
         set(MI_INTERPOSE "ON")
diff --git a/src/static.c b/src/static.c
index ec9370eb..bf86166d 100644
--- a/src/static.c
+++ b/src/static.c
@@ -24,5 +24,8 @@ terms of the MIT license. A copy of the license can be found in the file
 #include "alloc.c"
 #include "alloc-aligned.c"
 #include "alloc-posix.c"
+#if MI_OSX_ZONE
+#include "alloc-override-osx.c"
+#endif
 #include "init.c"
 #include "options.c"

From fe976caaea6d208f1c8499bdf5e478f35df6e67e Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <anton@korobeynikov.info>
Date: Tue, 21 Apr 2020 15:10:49 +0300
Subject: [PATCH 3/3] Provide zone_size function: free() uses it to find the
 zone pointer belongs to in order to call the corresponding zone_free function

---
 src/alloc-override-osx.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/alloc-override-osx.c b/src/alloc-override-osx.c
index cc03f5e2..c1c880ca 100644
--- a/src/alloc-override-osx.c
+++ b/src/alloc-override-osx.c
@@ -41,8 +41,11 @@ extern malloc_zone_t* malloc_default_purgeable_zone(void) __attribute__((weak_im
 ------------------------------------------------------ */
 
 static size_t zone_size(malloc_zone_t* zone, const void* p) {
-  UNUSED(zone); UNUSED(p);
-  return 0; // as we cannot guarantee that `p` comes from us, just return 0
+  UNUSED(zone);
+  if (!mi_is_in_heap_region(p))
+    return 0; // not our pointer, bail out
+  
+  return mi_usable_size(p);
 }
 
 static void* zone_malloc(malloc_zone_t* zone, size_t size) {