4 files changed, 39 insertions, 8 deletions
diff --git a/tools/eliminator/asm-eliminator-test-output.js b/tools/eliminator/asm-eliminator-test-output.js
index 4cf15c62..e477c320 100644
--- a/tools/eliminator/asm-eliminator-test-output.js
+++ b/tools/eliminator/asm-eliminator-test-output.js
@@ -108,4 +108,19 @@ function label() {
     i();
   }
 }
+function switchy() {
+  var no = 0, yes = 0;
+  while (1) switch (label | 0) {
+   case x:
+    no = 100;
+    break;
+   case y:
+    yes = 111;
+    yes = yes * 2;
+    print(yes);
+    yes--;
+    print(yes / 2);
+    continue;
+  }
+}
 
diff --git a/tools/eliminator/asm-eliminator-test.js b/tools/eliminator/asm-eliminator-test.js
index d2c0507c..acc07edb 100644
--- a/tools/eliminator/asm-eliminator-test.js
+++ b/tools/eliminator/asm-eliminator-test.js
@@ -141,5 +141,20 @@ function label() {
     i();
   }
 }
+function switchy() {
+  var no = 0, yes = 0;
+  while (1) switch (label | 0) {
+    case x:
+      no = 100; // eliminatable in theory, but eliminator does not look into switch. must leave def above as well.
+      break;
+    case y:
+      yes = 111;
+      yes = yes*2;
+      print(yes);
+      yes--;
+      print(yes/2);
+      continue;
+  }
+}
 // EMSCRIPTEN_GENERATED_FUNCTIONS: ["asm", "__Z11printResultPiS_j", "_segment_holding", "__ZN5identC2EiPKcPci", "_vec2Length", "exc", "label"]
 
diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index 5ede0ce8..598287db 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -1765,6 +1765,7 @@ function eliminate(ast, memSafe) {
     var values = {};
     var locals = {};
     var varsToRemove = {}; // variables being removed, that we can eliminate all 'var x;' of (this refers to 'var' nodes we should remove)
+                           // 1 means we should remove it, 2 means we successfully removed it
     var varsToTryToRemove = {}; // variables that have 0 uses, but have side effects - when we scan we can try to remove them
     // add arguments as locals
     if (func[2]) {
@@ -1822,7 +1823,7 @@ function eliminate(ast, memSafe) {
           });
         }
         if (!hasSideEffects) {
-          varsToRemove[name] = 1; // remove it normally
+          varsToRemove[name] = !definitions[name] ? 2 : 1; // remove it normally
           sideEffectFree[name] = true;
         } else {
           varsToTryToRemove[name] = 1; // try to remove it later during scanning
@@ -1979,7 +1980,7 @@ function eliminate(ast, memSafe) {
                 for (var i = 0; i < value.length; i++) {
                   node[i] = value[i];
                 }
-                varsToRemove[name] = 1;
+                varsToRemove[name] = 2;
               }
             } else {
               if (allowTracking) track(name, node[3], node);
@@ -2019,7 +2020,7 @@ function eliminate(ast, memSafe) {
                 for (var i = 0; i < value.length; i++) {
                   node[i] = value[i];
                 }
-                varsToRemove[name] = 1;
+                varsToRemove[name] = 2;
               }
             }
           }
@@ -2123,7 +2124,7 @@ function eliminate(ast, memSafe) {
     function doEliminate(name, node) {
       //printErr('elim!!!!! ' + name);
       // yes, eliminate!
-      varsToRemove[name] = 1; // both assign and var definitions can have other vars we must clean up
+      varsToRemove[name] = 2; // both assign and var definitions can have other vars we must clean up
       var info = tracked[name];
       delete tracked[name];
       var defNode = info.defNode;
@@ -2181,7 +2182,7 @@ function eliminate(ast, memSafe) {
     //printErr('cleaning up ' + JSON.stringify(varsToRemove));
     traverse(func, function(node, type) {
       if (type === 'var') {
-        node[1] = node[1].filter(function(pair) { return !(pair[0] in varsToRemove) });
+        node[1] = node[1].filter(function(pair) { return !varsToRemove[pair[0]] });
         if (node[1].length == 0) {
           // wipe out an empty |var;|
           node[0] = 'toplevel';
@@ -2192,7 +2193,7 @@ function eliminate(ast, memSafe) {
 
     if (asm) {
       for (var v in varsToRemove) {
-        delete asmData.vars[v];
+        if (varsToRemove[v] == 2) delete asmData.vars[v];
       }
       denormalizeAsm(func, asmData);
     }
diff --git a/tools/shared.py b/tools/shared.py
index a53c0a7b..eedb2e8b 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -729,13 +729,13 @@ set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)''' % { 'winfix': '' if not WINDOWS e
             basename = os.path.basename(f)
             cache[cache_name].append((basename, open(f, 'rb').read()))
         break
-      except:
+      except Exception, e:
         if i > 0:
           # Due to the ugly hack above our best guess is to output the first run
           with open_make_err(0) as ferr:
             for line in ferr:
               sys.stderr.write(line)
-          raise Exception('could not build library ' + name)
+          raise Exception('could not build library ' + name + ' due to exception ' + str(e))
     if old_dir:
       os.chdir(old_dir)
     return generated_libs