diff --git a/config/check_spidermonkey_style.py b/config/check_spidermonkey_style.py
index dde0104cca8e..cb456daccbc9 100644
--- a/config/check_spidermonkey_style.py
+++ b/config/check_spidermonkey_style.py
@@ -69,6 +69,7 @@ included_inclnames_to_ignore = set([
     'jscustomallocator.h',      # provided by embedders;  allowed to be missing
     'js-config.h',              # generated in $OBJDIR
     'fdlibm.h',                 # fdlibm
+    'mozmemory.h',              # included without a path
     'pratom.h',                 # NSPR
     'prcvar.h',                 # NSPR
     'prerror.h',                # NSPR
diff --git a/js/public/Utility.h b/js/public/Utility.h
index a2c53e4832fb..93ee414495e0 100644
--- a/js/public/Utility.h
+++ b/js/public/Utility.h
@@ -26,6 +26,8 @@
 
 #include "jstypes.h"
 
+#include "mozmemory.h"
+
 /* The public JS engine namespace. */
 namespace JS {}
 
@@ -364,22 +366,33 @@ struct MOZ_RAII JS_PUBLIC_DATA(AutoEnterOOMUnsafeRegion)
 
 } /* namespace js */
 
+// Malloc allocation.
+
+namespace js {
+
+extern JS_PUBLIC_DATA(arena_id_t) MallocArena;
+
+extern void InitMallocAllocator();
+extern void ShutDownMallocAllocator();
+
+} /* namespace js */
+
 static inline void* js_malloc(size_t bytes)
 {
     JS_OOM_POSSIBLY_FAIL();
-    return malloc(bytes);
+    return moz_arena_malloc(js::MallocArena, bytes);
 }
 
 static inline void* js_calloc(size_t bytes)
 {
     JS_OOM_POSSIBLY_FAIL();
-    return calloc(bytes, 1);
+    return moz_arena_calloc(js::MallocArena, bytes, 1);
 }
 
 static inline void* js_calloc(size_t nmemb, size_t size)
 {
     JS_OOM_POSSIBLY_FAIL();
-    return calloc(nmemb, size);
+    return moz_arena_calloc(js::MallocArena, nmemb, size);
 }
 
 static inline void* js_realloc(void* p, size_t bytes)
@@ -390,19 +403,18 @@ static inline void* js_realloc(void* p, size_t bytes)
     MOZ_ASSERT(bytes != 0);
 
     JS_OOM_POSSIBLY_FAIL();
-    return realloc(p, bytes);
+    return moz_arena_realloc(js::MallocArena, p, bytes);
 }
 
 static inline void js_free(void* p)
 {
+    // TODO: This should call |moz_arena_free(js::MallocArena, p)| but we
+    // currently can't enforce that all memory freed here was allocated by
+    // js_malloc().
     free(p);
 }
 
-static inline char* js_strdup(const char* s)
-{
-    JS_OOM_POSSIBLY_FAIL();
-    return strdup(s);
-}
+JS_PUBLIC_API(char*) js_strdup(const char* s);
 #endif/* JS_USE_CUSTOM_ALLOCATOR */
 
 #include <new>
diff --git a/js/src/jsapi-tests/testHashTable.cpp b/js/src/jsapi-tests/testHashTable.cpp
index 7919cf5b13df..35cf6b6370da 100644
--- a/js/src/jsapi-tests/testHashTable.cpp
+++ b/js/src/jsapi-tests/testHashTable.cpp
@@ -394,12 +394,13 @@ END_TEST(testHashMapLookupWithDefaultOOM)
 
 BEGIN_TEST(testHashTableMovableEnum)
 {
+    IntSet set;
     CHECK(set.init());
 
     // Exercise returning a hash table Enum object from a function.
 
     CHECK(set.put(1));
-    for (auto e = enumerateSet(); !e.empty(); e.popFront())
+    for (auto e = enumerateSet(set); !e.empty(); e.popFront())
         e.removeFront();
     CHECK(set.count() == 0);
 
@@ -425,9 +426,7 @@ BEGIN_TEST(testHashTableMovableEnum)
     return true;
 }
 
-IntSet set;
-
-IntSet::Enum enumerateSet()
+IntSet::Enum enumerateSet(IntSet& set)
 {
     return IntSet::Enum(set);
 }
diff --git a/js/src/jsapi-tests/tests.cpp b/js/src/jsapi-tests/tests.cpp
index 5671f161ea9a..6affbde9f9a8 100644
--- a/js/src/jsapi-tests/tests.cpp
+++ b/js/src/jsapi-tests/tests.cpp
@@ -45,6 +45,7 @@ void JSAPITest::uninit()
         destroyContext();
         cx = nullptr;
     }
+    msgs.clear();
 }
 
 bool JSAPITest::exec(const char* bytes, const char* filename, int lineno)
diff --git a/js/src/jsapi-tests/tests.h b/js/src/jsapi-tests/tests.h
index d580ad134fce..a9e0f24795e7 100644
--- a/js/src/jsapi-tests/tests.h
+++ b/js/src/jsapi-tests/tests.h
@@ -33,6 +33,7 @@ class JSAPITestString {
     const char* begin() const { return chars.begin(); }
     const char* end() const { return chars.end(); }
     size_t length() const { return chars.length(); }
+    void clear() { chars.clearAndFree(); }
 
     JSAPITestString& operator +=(const char* s) {
         if (!chars.append(s, strlen(s)))
diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp
index 7fde0b04463e..700ea1e037fc 100644
--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -3868,7 +3868,12 @@ js::DuplicateString(JSContext* cx, const char16_t* s)
 UniqueChars
 js::DuplicateString(const char* s)
 {
-    return UniqueChars(js_strdup(s));
+    size_t n = strlen(s) + 1;
+    UniqueChars ret(js_pod_malloc<char>(n));
+    if (!ret)
+        return ret;
+    PodCopy(ret.get(), s, n);
+    return ret;
 }
 
 UniqueChars
@@ -3899,6 +3904,12 @@ js::DuplicateString(const char16_t* s, size_t n)
     return ret;
 }
 
+JS_PUBLIC_API(char*)
+js_strdup(const char* s)
+{
+    return DuplicateString(s).release();
+}
+
 template <typename CharT>
 const CharT*
 js_strchr_limit(const CharT* s, char16_t c, const CharT* limit)
diff --git a/js/src/jsutil.cpp b/js/src/jsutil.cpp
index a973a7f39101..ffa095eee8b8 100644
--- a/js/src/jsutil.cpp
+++ b/js/src/jsutil.cpp
@@ -170,6 +170,20 @@ ResetSimulatedInterrupt()
 } // namespace js
 #endif // defined(DEBUG) || defined(JS_OOM_BREAKPOINT)
 
+JS_PUBLIC_DATA(arena_id_t) js::MallocArena;
+
+void
+js::InitMallocAllocator()
+{
+    MallocArena = moz_create_arena();
+}
+
+void
+js::ShutDownMallocAllocator()
+{
+    moz_dispose_arena(MallocArena);
+}
+
 JS_PUBLIC_API(void)
 JS_Assert(const char* s, const char* file, int ln)
 {
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 08020fdf536f..498d3ba136a0 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -3992,6 +3992,8 @@ KillWorkerThreads(JSContext* cx)
         thread->join();
     }
 
+    workerThreads.clearAndFree();
+
     js_delete(workerThreadsLock);
     workerThreadsLock = nullptr;
 
@@ -4927,12 +4929,12 @@ NestedShell(JSContext* cx, unsigned argc, Value* vp)
         JS_ReportErrorNumberASCII(cx, my_GetErrorMessage, nullptr, JSSMSG_NESTED_FAIL);
         return false;
     }
-    if (!argv.append(strdup(sArgv[0])))
+    if (!argv.append(js_strdup(sArgv[0])))
         return false;
 
     // Propagate selected flags from the current shell
     for (unsigned i = 0; i < sPropagatedFlags.length(); i++) {
-        char* cstr = strdup(sPropagatedFlags[i]);
+        char* cstr = js_strdup(sPropagatedFlags[i]);
         if (!cstr || !argv.append(cstr))
             return false;
     }
@@ -5753,6 +5755,7 @@ ShutdownBufferStreams()
     state->shutdown = true;
     while (!state->jobs.empty())
         state.wait(/* jobs empty */);
+    state->jobs.clearAndFree();
 }
 
 static bool
@@ -8652,6 +8655,12 @@ main(int argc, char** argv, char** envp)
     SetOutputFile("JS_STDOUT", &rcStdout, &gOutFile);
     SetOutputFile("JS_STDERR", &rcStderr, &gErrFile);
 
+    // Start the engine.
+    if (!JS_Init())
+        return 1;
+
+    auto shutdownEngine = MakeScopeExit([]() { JS_ShutDown(); });
+
     OptionParser op("Usage: {progname} [options] [[script] scriptArgs*]");
 
     op.setDescription("The SpiderMonkey shell provides a command line interface to the "
@@ -8875,10 +8884,6 @@ main(int argc, char** argv, char** envp)
     if (op.getBoolOption("no-threads"))
         js::DisableExtraThreads();
 
-    // Start the engine.
-    if (!JS_Init())
-        return 1;
-
     if (!InitSharedArrayBufferMailbox())
         return 1;
 
@@ -8979,6 +8984,5 @@ main(int argc, char** argv, char** envp)
     DestructSharedArrayBufferMailbox();
 
     JS_DestroyContext(cx);
-    JS_ShutDown();
     return result;
 }
diff --git a/js/src/vm/Initialization.cpp b/js/src/vm/Initialization.cpp
index 3ef67db836ff..1b035a67e004 100644
--- a/js/src/vm/Initialization.cpp
+++ b/js/src/vm/Initialization.cpp
@@ -100,6 +100,8 @@ JS::detail::InitWithFailureDiagnostic(bool isDebugBuild)
     RETURN_IF_FAIL(js::oom::InitThreadType());
 #endif
 
+    js::InitMallocAllocator();
+
     RETURN_IF_FAIL(js::Mutex::Init());
 
     RETURN_IF_FAIL(js::wasm::InitInstanceStaticData());
@@ -170,6 +172,7 @@ JS_ShutDown(void)
     js::MemoryProtectionExceptionHandler::uninstall();
 
     js::wasm::ShutDownInstanceStaticData();
+    js::wasm::ShutDownProcessStaticData();
 
     js::Mutex::ShutDown();
 
@@ -199,6 +202,8 @@ JS_ShutDown(void)
         js::jit::ReleaseProcessExecutableMemory();
     }
 
+    js::ShutDownMallocAllocator();
+
     libraryInitState = InitState::ShutDown;
 }
 
diff --git a/js/src/wasm/WasmProcess.cpp b/js/src/wasm/WasmProcess.cpp
index afc378eac189..9a9920bdb22a 100644
--- a/js/src/wasm/WasmProcess.cpp
+++ b/js/src/wasm/WasmProcess.cpp
@@ -126,6 +126,13 @@ class ProcessCodeSegmentMap
         MOZ_ASSERT(segments2_.empty());
     }
 
+    void freeAll() {
+        MOZ_ASSERT(segments1_.empty());
+        MOZ_ASSERT(segments2_.empty());
+        segments1_.clearAndFree();
+        segments2_.clearAndFree();
+    }
+
     bool insert(const CodeSegment* cs) {
         LockGuard<Mutex> lock(mutatorsMutex_);
 
@@ -230,3 +237,9 @@ wasm::LookupCode(const void* pc)
     const CodeSegment* found = LookupCodeSegment(pc);
     return found ? found->code() : nullptr;
 }
+
+void
+wasm::ShutDownProcessStaticData()
+{
+    processCodeSegmentMap.freeAll();
+}
diff --git a/js/src/wasm/WasmProcess.h b/js/src/wasm/WasmProcess.h
index 08d25d9adfc7..d5b125a1fd35 100644
--- a/js/src/wasm/WasmProcess.h
+++ b/js/src/wasm/WasmProcess.h
@@ -51,6 +51,9 @@ RegisterCodeSegment(const CodeSegment* cs);
 void
 UnregisterCodeSegment(const CodeSegment* cs);
 
+void
+ShutDownProcessStaticData();
+
 } // namespace wasm
 } // namespace js