5 files changed, 42 insertions, 16 deletions

diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 3f9427ed7..73a536903 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -233,17 +233,17 @@ private:
       Flow visitBreak(Break *curr) {
         NOTE_ENTER("Break");
         bool condition = true;
-        if (curr->condition) {
-          Flow flow = visit(curr->condition);
-          if (flow.breaking()) return flow;
-          condition = flow.value.getInteger();
-        }
         Flow flow(curr->name);
         if (curr->value) {
           flow = visit(curr->value);
           if (flow.breaking()) return flow;
           flow.breakTo = curr->name;
         }
+        if (curr->condition) {
+          Flow conditionFlow = visit(curr->condition);
+          if (conditionFlow.breaking()) return conditionFlow;
+          condition = conditionFlow.value.getInteger();
+        }
         return condition ? flow : Flow();
       }
       Flow visitSwitch(Switch *curr) {
diff --git a/src/wasm-js.cpp b/src/wasm-js.cpp
index 067e3fdea..82a74d2ab 100644
--- a/src/wasm-js.cpp
+++ b/src/wasm-js.cpp
@@ -311,8 +311,8 @@ extern "C" void EMSCRIPTEN_KEEPALIVE call_from_js(const char *target) {
   if (wasmJSDebug) std::cout << "call_from_js returning " << ret << '\n';
 
   if (ret.type == none) EM_ASM({ Module['tempReturn'] = undefined });
-  else if (ret.type == i32) EM_ASM_({ Module['tempReturn'] = $0 }, ret.i32);
-  else if (ret.type == f32) EM_ASM_({ Module['tempReturn'] = $0 }, ret.f32);
-  else if (ret.type == f64) EM_ASM_({ Module['tempReturn'] = $0 }, ret.f64);
+  else if (ret.type == i32) EM_ASM_({ Module['tempReturn'] = $0 }, ret.geti32());
+  else if (ret.type == f32) EM_ASM_({ Module['tempReturn'] = $0 }, ret.getf32());
+  else if (ret.type == f64) EM_ASM_({ Module['tempReturn'] = $0 }, ret.getf64());
   else abort();
 }
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index dc946fc3b..ce216fd8e 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -868,10 +868,6 @@ private:
   Expression* makeBreak(Element& s) {
     auto ret = allocator.alloc<Break>();
     size_t i = 1;
-    if (s[0]->str() == BR_IF) {
-      ret->condition = parseExpression(s[i]);
-      i++;
-    }
     if (s[i]->dollared()) {
       ret->name = s[i]->str();
     } else {
@@ -881,7 +877,14 @@ private:
       ret->name = labelStack[labelStack.size() - 1 - offset];
     }
     i++;
-    if (i < s.size()) {
+    if (i == s.size()) return ret;
+    if (s[0]->str() == BR_IF) {
+      if (i + 1 < s.size()) {
+        ret->value = parseExpression(s[i]);
+        i++;
+      }
+      ret->condition = parseExpression(s[i]);
+    } else {
       ret->value = parseExpression(s[i]);
     }
     return ret;
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
index ba4e5fe08..fad33a081 100644
--- a/src/wasm-validator.h
+++ b/src/wasm-validator.h
@@ -28,6 +28,8 @@ namespace wasm {
 struct WasmValidator : public WasmWalker<WasmValidator> {
   bool valid;
 
+  std::map<Name, WasmType> breakTypes; // breaks to a label must all have the same type, and the right type
+
 public:
   bool validate(Module& module) {
     valid = true;
@@ -37,6 +39,15 @@ public:
 
   // visitors
 
+  void visitBlock(Block *curr) {
+    // if we are break'ed to, then the value must be right for us
+    if (curr->name.is()) {
+      if (breakTypes.count(curr->name) > 0) {
+        shouldBeTrue(curr->type == breakTypes[curr->name]);
+        breakTypes.erase(curr->name);
+      }
+    }
+  }
   void visitLoop(Loop *curr) {
     if (curr->in.is()) {
       LoopChildChecker childChecker(curr->in);
@@ -44,6 +55,17 @@ public:
       shouldBeTrue(childChecker.valid);
     }
   }
+  void visitBreak(Break *curr) {
+    WasmType valueType = none;
+    if (curr->value) {
+      valueType = curr->value->type;
+    }
+    if (breakTypes.count(curr->name) == 0) {
+      breakTypes[curr->name] = valueType;
+    } else {
+      shouldBeTrue(valueType == breakTypes[curr->name]);
+    }
+  }
   void visitSetLocal(SetLocal *curr) {
     shouldBeTrue(curr->type == curr->value->type);
   }
diff --git a/src/wasm.h b/src/wasm.h
index 893c777c4..20a7b34ef 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -511,10 +511,8 @@ public:
 
   std::ostream& doPrint(std::ostream &o, unsigned indent) {
     if (condition) {
-      printOpening(o, "br_if");
+      printOpening(o, "br_if ") << name;
       incIndent(o, indent);
-      printFullLine(o, indent, condition);
-      doIndent(o, indent) << name << '\n';
     } else {
       printOpening(o, "br ") << name;
       if (!value || value->is<Nop>()) {
@@ -525,6 +523,9 @@ public:
       incIndent(o, indent);
     }
     if (value && !value->is<Nop>()) printFullLine(o, indent, value);
+    if (condition) {
+      printFullLine(o, indent, condition);
+    }
     return decIndent(o, indent);
   }
 };