2 files changed, 57 insertions, 5 deletions
diff --git a/src/corruptionCheck.js b/src/corruptionCheck.js
index d676c290..8698b86d 100644
--- a/src/corruptionCheck.js
+++ b/src/corruptionCheck.js
@@ -14,6 +14,11 @@ var CorruptionChecker = {
     this.realFree = _free;
     _free = Module['_free'] = this.free;
 
+    if (typeof _realloc != 'undefined') {
+      this.realRealloc = _realloc;
+      _realloc = Module['_realloc'] = this.realloc;
+    }
+
     __ATEXIT__.push({ func: function() {
       Module.printErr('No corruption detected, ran ' + CorruptionChecker.checks + ' checks.');
     } });
@@ -42,17 +47,33 @@ var CorruptionChecker = {
     delete CorruptionChecker.ptrs[ptr];
     CorruptionChecker.realFree(allocation);
   },
+  realloc: function(ptr, newSize) {
+    //Module.print('realloc ' + ptr + ' to size ' + newSize);
+    if (newSize <= 0) newSize = 1; // like in malloc
+    if (!ptr) return CorruptionChecker.malloc(newSize); // realloc(NULL, size) forwards to malloc according to the spec
+    var size = CorruptionChecker.ptrs[ptr];
+    assert(size);
+    var allocation = ptr - size*CorruptionChecker.BUFFER_FACTOR;
+    var newPtr = CorruptionChecker.malloc(newSize);
+    //Module.print('realloc ' + ptr + ' to size ' + newSize + ' is now ' + newPtr);
+    var newAllocation = newPtr + newSize*CorruptionChecker.BUFFER_FACTOR;
+    HEAPU8.set(HEAPU8.subarray(ptr, ptr + Math.min(size, newSize)), newPtr);
+    CorruptionChecker.free(ptr);
+    return newPtr;
+  },
   canary: function(x) {
     return (x&127) + 10;
   },
-  fillBuffer: function(allocation, size) {
-    for (var x = allocation; x < allocation + size; x++) {
+  fillBuffer: function(buffer, size) {
+    for (var x = buffer; x < buffer + size; x++) {
       {{{ makeSetValue('x', 0, 'CorruptionChecker.canary(x)', 'i8') }}};
     }
   },
-  checkBuffer: function(allocation, size) {
-    for (var x = allocation; x < allocation + size; x++) {
-      assert(({{{ makeGetValue('x', 0, 'i8') }}}&255) == CorruptionChecker.canary(x), 'Heap corruption detected!');
+  checkBuffer: function(buffer, size) {
+    for (var x = buffer; x < buffer + size; x++) {
+      if (({{{ makeGetValue('x', 0, 'i8') }}}&255) != CorruptionChecker.canary(x)) {
+        assert(0, 'Heap corruption detected!' + [x, buffer, size, {{{ makeGetValue('x', 0, 'i8') }}}&255, CorruptionChecker.canary(x)]);
+      }
     }
     CorruptionChecker.checks++;
   },
diff --git a/tests/runner.py b/tests/runner.py
index f0340cd0..3b2fcd58 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -7250,6 +7250,37 @@ def process(filename):
         '''
       self.do_run(src, 'missing!\nall ok\n')
 
+    def test_corruption_3(self):
+      if Settings.ASM_JS: return self.skip('cannot use corruption checks in asm')
+      if Settings.USE_TYPED_ARRAYS != 2: return self.skip('needs ta2 for actual test')
+
+      Settings.CORRUPTION_CHECK = 1
+
+      # realloc
+      src = r'''
+        #include <stdlib.h>
+        #include <stdio.h>
+        #include <assert.h>
+
+        void bye() {
+          printf("all ok\n");
+        }
+
+        int main(int argc, char **argv) {
+          atexit(bye);
+
+          char *buffer = (char*)malloc(100);
+          for (int i = 0; i < 100; i++) buffer[i] = (i*i)%256;
+          buffer = (char*)realloc(buffer, argc + 50);
+          for (int i = 0; i < argc + 50; i++) {
+            //printf("%d : %d : %d : %d\n", i, (int)(buffer + i), buffer[i], (char)((i*i)%256));
+            assert(buffer[i] == (char)((i*i)%256));
+          }
+          return 1;
+        }
+        '''
+      self.do_run(src, 'all ok\n')
+
     ### Integration tests
 
     def test_ccall(self):