1 files changed, 21 insertions, 28 deletions

diff --git a/src/parseTools.js b/src/parseTools.js
index ca9ad40a..6e0d6e32 100644
--- a/src/parseTools.js
+++ b/src/parseTools.js
@@ -103,6 +103,11 @@ function isNiceIdent(ident, loose) {
   }
 }
 
+function isJSVar(ident) {
+  return /^\(?[$_]?[\w$_\d ]*\)+$/.test(ident);
+
+}
+
 function isStructPointerType(type) {
   // This test is necessary for clang - in llvm-gcc, we
   // could check for %struct. The downside is that %1 can
@@ -988,7 +993,8 @@ function getHeapOffset(offset, type, forceAsm) {
     if (shifts != 0) {
       return '(' + offset + '>>' + shifts + ')';
     } else {
-      return offset;
+      // we need to guard against overflows here, HEAP[U]8 expects a guaranteed int
+      return isJSVar(offset) ? offset : '(' + offset + '|0)';
     }
   }
 }
@@ -1038,20 +1044,6 @@ function asmCoercion(value, type, signedness) {
   }
 }
 
-var TWO_TWENTY = Math.pow(2, 20);
-
-function asmMultiplyI32(a, b) {
-  // special-case: there is no integer multiply in asm, because there is no true integer
-  // multiply in JS. While we wait for Math.imul, do double multiply
-  if ((isNumber(a) && Math.abs(a) < TWO_TWENTY) || (isNumber(b) && Math.abs(b) < TWO_TWENTY)) {
-    return '(((' + a + ')*(' + b + '))&-1)'; // small enough to emit directly as a multiply
-  }
-  if (USE_MATH_IMUL) {
-    return 'Math.imul(' + a + ',' + b + ')';
-  }
-  return '(~~(+((' + a + ')|0) * +((' + b + ')|0)))';
-}
-
 function asmFloatToInt(x) {
   return '(~~(' + x + '))';
 }
@@ -1145,8 +1137,8 @@ function makeGetValue(ptr, pos, type, noNeedFirst, unsigned, ignore, align, noSa
   }
 }
 
-function makeGetValueAsm(ptr, pos, type) {
-  return makeGetValue(ptr, pos, type, null, null, null, null, null, true);
+function makeGetValueAsm(ptr, pos, type, unsigned) {
+  return makeGetValue(ptr, pos, type, null, unsigned, null, null, null, true);
 }
 
 function indexizeFunctions(value, type) {
@@ -1364,9 +1356,11 @@ function makeHEAPView(which, start, end) {
 var PLUS_MUL = set('+', '*');
 var MUL_DIV = set('*', '/');
 var PLUS_MINUS = set('+', '-');
+var TWO_TWENTY = Math.pow(2, 20);
 
 // Given two values and an operation, returns the result of that operation.
 // Tries to do as much as possible at compile time.
+// Leaves overflows etc. unhandled, *except* for integer multiply, in order to be efficient with Math.imul
 function getFastValue(a, op, b, type) {
   a = a.toString();
   b = b.toString();
@@ -1402,8 +1396,14 @@ function getFastValue(a, op, b, type) {
           return '(' + a + '<<' + shifts + ')';
         }
       }
-      if (ASM_JS && !(type in Runtime.FLOAT_TYPES)) {
-        return asmMultiplyI32(a, b); // unoptimized multiply, do it using asm.js's special multiply operation
+      if (!(type in Runtime.FLOAT_TYPES)) {
+        // if guaranteed small enough to not overflow into a double, do a normal multiply
+        var bits = getBits(type) || 32; // default is 32-bit multiply for things like getelementptr indexes
+        // Note that we can emit simple multiple in non-asm.js mode, but asm.js will not parse "16-bit" multiple, so must do imul there
+        if ((isNumber(a) && Math.abs(a) < TWO_TWENTY) || (isNumber(b) && Math.abs(b) < TWO_TWENTY) || (bits < 32 && !ASM_JS)) {
+          return '(((' + a + ')*(' + b + '))&' + ((Math.pow(2, bits)-1)|0) + ')'; // keep a non-eliminatable coercion directly on this
+        }
+        return 'Math.imul(' + a + ',' + b + ')';
       }
     } else {
       if (a == '0') {
@@ -1548,7 +1548,7 @@ function makePointer(slab, pos, allocator, type, ptr) {
     var ret = '';
     var index = 0;
     while (index < array.length) {
-      ret = (ret ? ret + '.concat(' : '') + '[' + array.slice(index, index + chunkSize).map(JSON.stringify) + ']' + (ret ? ')' : '');
+      ret = (ret ? ret + '.concat(' : '') + '[' + array.slice(index, index + chunkSize).map(JSON.stringify) + ']' + (ret ? ')\n' : '');
       index += chunkSize;
     }
     return ret;
@@ -2130,14 +2130,7 @@ function processMathop(item) {
     case 'add': return handleOverflow(getFastValue(idents[0], '+', idents[1], item.type), bits);
     case 'sub': return handleOverflow(getFastValue(idents[0], '-', idents[1], item.type), bits);
     case 'sdiv': case 'udiv': return makeRounding(getFastValue(idents[0], '/', idents[1], item.type), bits, op[0] === 's');
-    case 'mul': {
-      if (bits == 32 && PRECISE_I32_MUL) {
-        Types.preciseI64MathUsed = true;
-        return '(i64Math' + (ASM_JS ? '_' : '.') + 'multiply(' + asmCoercion(idents[0], 'i32') + ',0,' + asmCoercion(idents[1], 'i32') + ',0),' + makeGetValue('tempDoublePtr', 0, 'i32') + ')';
-      } else {
-        return '((' +getFastValue(idents[0], '*', idents[1], item.type) + ')&-1)'; // force a non-eliminatable coercion here, to prevent a double result from leaking
-      }
-    }
+    case 'mul': return getFastValue(idents[0], '*', idents[1], item.type); // overflow handling is already done in getFastValue for '*'
     case 'urem': case 'srem': return getFastValue(idents[0], '%', idents[1], item.type);
     case 'or': {
       if (bits > 32) {