Merge pull request #176 from jterrace/mmap_allocate_opts

mmap and allocate optimizations

3 files changed, 43 insertions, 2 deletions

diff --git a/src/library.js b/src/library.js
index b07ab21d..5bdc64f4 100644
--- a/src/library.js
+++ b/src/library.js
@@ -3184,7 +3184,9 @@ LibraryManager.library = {
      * mmap.
      */
     if (stream == -1) {
-      return allocate(num, 'i8', ALLOC_NORMAL);
+      var ptr = _malloc(num);
+      _memset(ptr, 0, num);
+      return ptr;
     }
     var info = FS.streams[stream];
     if (!info) return -1;
diff --git a/src/preamble.js b/src/preamble.js
index 0b9288c4..5c5c21ea 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -462,9 +462,14 @@ function allocate(slab, types, allocator) {
 
   var ret = [_malloc, Runtime.stackAlloc, Runtime.staticAlloc][allocator === undefined ? ALLOC_STATIC : allocator](Math.max(size, singleType ? 1 : types.length));
 
+  if (zeroinit) {
+      _memset(ret, 0, size);
+      return ret;
+  }
+  
   var i = 0, type;
   while (i < size) {
-    var curr = zeroinit ? 0 : slab[i];
+    var curr = slab[i];
 
     if (typeof curr === 'function') {
       curr = Runtime.getFunctionIndex(curr);
diff --git a/tests/runner.py b/tests/runner.py
index b90eda35..1ea50f79 100644
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -3975,6 +3975,40 @@ def process(filename):
         }
       '''
       self.do_run(src, 'value:10')
+      
+    def test_mmap(self):
+      src = '''
+        #include <stdio.h>
+        #include <sys/types.h>
+        #include <sys/mman.h>
+        #include <assert.h>
+        
+        int main(int argc, char *argv[]) {
+            const int NUM_BYTES = 8 * 1024 * 1024;
+            const int NUM_INTS = NUM_BYTES / sizeof(int);
+        
+            int* map = (int*)mmap(0, NUM_BYTES, PROT_READ | PROT_WRITE,
+                    MAP_SHARED | MAP_ANON, -1, 0);
+            assert(map != MAP_FAILED);
+        
+            int i;
+        
+            for (i = 0; i < NUM_INTS; i++) {
+                map[i] = i;
+            }
+        
+            for (i = 0; i < NUM_INTS; i++) {
+                assert(map[i] == i);
+            }
+        
+            assert(munmap(map, NUM_BYTES) == 0);
+            
+            printf("hello,world");
+            return 0;
+        }
+      '''
+      self.do_run(src, 'hello,world')
+      self.do_run(src, 'hello,world', force_c=True)
 
     def test_cubescript(self):
       if self.emcc_args is not None and '-O2' in self.emcc_args: