optimize Pointer_make (both input size and processing time)

emscripten-core · Jun 5, 2011 · c5d4ba7 · c5d4ba7
1 parent 304221e
commit c5d4ba7
Show file tree

Hide file tree

Showing 3 changed files with 67 additions and 19 deletions.
diff --git a/src/library.js b/src/library.js
@@ -900,7 +900,7 @@ var Library = {
         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
         0,0,0,0,0,0,0,0,0,0,0
       ];
-      me.ret = Pointer_make([Pointer_make(values, 0, ALLOC_STATIC, 'void*')+256], 0, ALLOC_STATIC, 'i16');
+      me.ret = Pointer_make([Pointer_make(values, 0, ALLOC_STATIC, 'i16')+256], 0, ALLOC_STATIC, 'void*');
 #if USE_TYPED_ARRAYS == 0
       assert(HEAP[HEAP[me.ret]] == 2);
       assert(HEAP[HEAP[me.ret]-2] == 0);

diff --git a/src/parseTools.js b/src/parseTools.js
@@ -585,7 +585,7 @@ function generateStructTypes(type) {
       ret = ret.concat(zeros(typeData.flatIndexes[i+1] - ret.length));
     }
   }
-  return ret;
+  return ret.concat(zeros(typeData.flatSize - ret.length));
 }
 
 // Flow blocks
@@ -819,7 +819,31 @@ function makePointer(slab, pos, allocator, type) {
   assert(type, 'makePointer requires type info');
   if (slab.substr(0, 4) === 'HEAP' || (USE_TYPED_ARRAYS == 1 && slab in set('IHEAP', 'FHEAP'))) return pos;
   var types = generateStructTypes(type);
-  if (dedup(types).length === 1) types = types[0];
+
+  // compress type info and data if possible
+  var de;
+  try {
+    // compress all-zeros into a number (which will become zeros(..)).
+    // note that we cannot always eval the slab, e.g., if it contains ident,0,0 etc. In that case, no compression TODO: ensure we get arrays here, not str
+    var evaled = typeof slab === 'string' ? eval(slab) : slab;
+    de = dedup(evaled);
+    if (de.length === 1 && de[0] === 0) {
+      slab = evaled.length;
+    }
+    // TODO: if not all zeros, at least filter out items with type === 0. requires cleverness to know how to skip at runtime though. also
+    //       be careful of structure padding
+  } catch(e){}
+  de = dedup(types);
+  if (de.length === 1) {
+    types = de[0];
+  } else if (de.length === 2 && typeof slab === 'number') {
+    // If slab is all zeros, we can compress types even if we have i32,0,0,0,i32,0,0,0 etc. - we do not need the zeros
+    de = de.filter(function(x) { return x !== 0 });
+    if (de.length === 1) {
+      types = de[0];
+    }
+  }
+
   return 'Pointer_make(' + slab + ', ' + (pos ? pos : 0) + (allocator ? ', ' + allocator : '') + ', ' +
          JSON.stringify(types) +
          ')';

diff --git a/src/preamble.js b/src/preamble.js
@@ -262,32 +262,56 @@ function Pointer_make(slab, pos, allocator, types) {
   pos = pos ? pos : 0;
   assert(pos === 0); // TODO: remove 'pos'
   if (slab === HEAP) return pos;
-  var size = slab.length;
-
-  var i;
-#if ASSERTIONS
-  for (i = 0; i < size; i++) {
-    if (slab[i] === undefined) {
-      throw 'Invalid element in slab at ' + new Error().stack; // This can be caught, and you can try again to allocate later, see globalFuncs in run()
-    }
+  var zeroinit, size;
+  if (typeof slab === 'number') {
+    zeroinit = true;
+    size = slab;
+  } else {
+    zeroinit = false;
+    size = slab.length;
   }
-#endif
 
   // Finalize
   var ret = [_malloc, Runtime.stackAlloc, Runtime.staticAlloc][allocator ? allocator : ALLOC_STATIC](Math.max(size, 1));
 
-  var type = typeof types === 'string' ? types : null;
+  var singleType = typeof types === 'string' ? types : null;
 
-  for (i = 0; i < size; i++) {
-    var curr = slab[i];
+  var i = 0, type;
+  while (i < size) {
+    var curr = zeroinit ? 0 : slab[i];
 
     if (typeof curr === 'function') {
       curr = Runtime.getFunctionIndex(curr);
     }
 
-    if (type || types[i]) {
-      {{{ makeSetValue(0, 'ret+i', 'curr', '#type || types[i]') }}}
+    type = singleType || types[i];
+    if (type === 0) {
+      i++;
+      continue;
     }
+#if ASSERTIONS
+    assert(type, 'Must know what type to store in Pointer_make!');
+#endif
+
+    if (type === 'i8') {
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'i8') }}}
+      i += {{{ getNativeFieldSize('i8', true) }}};
+    } else if (type === 'i16') {
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'i16') }}}
+      i += {{{ getNativeFieldSize('i16', true) }}};
+    } else if (type === 'i32' || type[type.length-1] === '*') { // hardcoded pointers as 32-bit
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'i32') }}}
+      i += {{{ getNativeFieldSize('i32', true) }}};
+    } else if (type === 'i64') {
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'i64') }}}
+      i += {{{ getNativeFieldSize('i64', true) }}};
+    } else if (type === 'float') {
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'float') }}}
+      i += {{{ getNativeFieldSize('float', true) }}};
+    } else if (type === 'double') {
+      {{{ makeSetValue(0, 'ret+i', 'curr', 'double') }}}
+      i += {{{ getNativeFieldSize('double', true) }}};
+    } else throw 'invalid type for Pointer_make: ' + type;
   }
 
   return ret;
@@ -488,8 +512,8 @@ function intArrayToString(array) {
   return ret;
 }
 
-var unSign = {{{ unSign.toString() }}}
-var reSign = {{{ reSign.toString() }}}
+{{{ unSign }}}
+{{{ reSign }}}
 
 // Use console read if available, otherwise we are in a browser, use an XHR
 if (!this['read']) {