perf: abort on mimalloc allocation failure

src/include/lean/lean.h

@@ -353,7 +353,6 @@ static inline lean_object * lean_alloc_small_object(unsigned sz) {
     // HACK: emulate behavior of small allocator to avoid `leangz` breakage for now
     sz = lean_align(sz, LEAN_OBJECT_SIZE_DELTA);
     void * mem = mi_malloc_small(sz);
-    if (mem == 0) lean_internal_panic_out_of_memory();
     lean_object * o = (lean_object*)mem;
     o->m_cs_sz = sz;
     return o;

src/runtime/CMakeLists.txt

@@ -12,7 +12,7 @@ if (USE_MIMALLOC)
     # (C flags are incomplete, compile as C++ instead like everything else)
     LANGUAGE CXX
     # make all symbols visible, always build with optimizations as otherwise Lean becomes too slow
-    COMPILE_FLAGS "-DMI_SHARED_LIB -DMI_SHARED_LIB_EXPORT -O3 -DNDEBUG -DMI_WIN_NOREDIRECT")
+    COMPILE_FLAGS "-DMI_SHARED_LIB -DMI_SHARED_LIB_EXPORT -O3 -DNDEBUG -DMI_WIN_NOREDIRECT -DMI_XMALLOC")
 endif()
 
 add_library(leanrt_initial-exec STATIC ${RUNTIME_OBJS})

src/runtime/object.cpp

@@ -298,7 +298,6 @@ extern "C" LEAN_EXPORT lean_object * lean_alloc_object(size_t sz) {
     return (lean_object*)alloc(sz);
 #elif defined(LEAN_MIMALLOC)
     void * r = mi_malloc(sz);
-    if (r == nullptr) lean_internal_panic_out_of_memory();
     lean_object * o = (lean_object*)r;
     // not a small object
     o->m_cs_sz = 0;