strengthen SAFE_HEAP in malloc and on the stack

src/library.js

@@ -385,6 +385,10 @@ var Library = {
     var now = Date.now();
     IHEAP[ptr + indexes[0]] = Math.floor(now/1000); // seconds
     IHEAP[ptr + indexes[1]] = Math.floor((now-1000*Math.floor(now/1000))*1000); // microseconds
+#if SAFE_HEAP
+    SAFE_HEAP_ACCESS(ptr + indexes[0], 'i32', true);
+    SAFE_HEAP_ACCESS(ptr + indexes[1], 'i32', true);
+#endif
     return 0;
   },
 

src/runtime.js

@@ -5,10 +5,7 @@
 RuntimeGenerator = {
   alloc: function(size, type) {
     var ret = type + 'TOP';
-//    ret += '; for (var i = 0; i < ' + size + '; i++) HEAP[' + type + 'TOP+i] = 0'; // No need for typed arrays - per the spec, initialized to 0 anyhow
-    if (SAFE_HEAP) {
-      ret += '; for (var j = 0; j < ' + size + '; j++) SAFE_HEAP_CLEAR(' + type + 'TOP+j);';
-    }
+    //ret += '; for (var i = 0; i < ' + size + '; i++) HEAP[' + type + 'TOP+i] = 0'; // No need for typed arrays - per the spec, initialized to 0 anyhow
     if (GUARD_MEMORY) {
       ret += '; assert(' + size + ' > 0)';
     }
@@ -29,14 +26,11 @@ RuntimeGenerator = {
   },
 
   stackEnter: function(initial) {
-    if (!GUARD_MEMORY && initial === 0) return ''; // XXX Note that we don't even push the stack! This is faster, but
-                                                   // means that we don't clear stack allocations done in this function
-                                                   // until the parent unwinds its stack. So potentially if we are in
-                                                   // a loop, we can use a lot of memory.
+    if (initial === 0) return ''; // XXX Note that we don't even push the stack! This is faster, but
+                                  // means that we don't clear stack allocations done in this function
+                                  // until the parent unwinds its stack. So potentially if we are in
+                                  // a loop, we can use a lot of memory.
     var ret = 'var __stackBase__  = STACKTOP; STACKTOP += ' + initial;
-    if (SAFE_HEAP) {
-      ret += '; for (var i = __stackBase__; i < STACKTOP; i++) SAFE_HEAP_STORE(i, 0, null);';
-    }
     if (GUARD_MEMORY) {
       ret += '; assert(STACKTOP < STACK_MAX)';
     }