update if parsing to new spec rules

4 files changed, 84 insertions, 16 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index cb1998aa4..be11344b2 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -28,6 +28,7 @@
 #include "shared-constants.h"
 #include "asm_v_wasm.h"
 #include "pass.h"
+#include "ast_utils.h"
 
 namespace wasm {
 
@@ -66,17 +67,6 @@ struct AstStackHelper {
 
 std::vector<Ref> AstStackHelper::astStack;
 
-struct BreakSeeker : public WasmWalker<BreakSeeker> {
-  IString target; // look for this one
-  size_t found;
-
-  BreakSeeker(IString target) : target(target), found(false) {}
-
-  void visitBreak(Break *curr) {
-    if (curr->name == target) found++;
-  }
-};
-
 //
 // Asm2WasmPreProcessor - does some initial parsing/processing
 // of asm.js code.
diff --git a/src/ast_utils.h b/src/ast_utils.h
new file mode 100644
index 000000000..df2ffe578
--- /dev/null
+++ b/src/ast_utils.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2016 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef wasm_ast_utils_h
+#define wasm_ast_utils_h
+
+#include "wasm.h"
+
+namespace wasm {
+
+struct BreakSeeker : public WasmWalker<BreakSeeker> {
+  Name target; // look for this one
+  size_t found;
+
+  BreakSeeker(Name target) : target(target), found(false) {}
+
+  void visitBreak(Break *curr) {
+    if (curr->name == target) found++;
+  }
+
+  static bool has(Expression* tree, Name target) {
+    BreakSeeker breakSeeker(target);
+    breakSeeker.walk(tree);
+    return breakSeeker.found > 0;
+  }
+};
+
+} // namespace wasm
+
+#endif // wasm_ast_utils_h
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index f365db02f..e8e917a6e 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -65,11 +65,22 @@ struct PrintSExpression : public WasmVisitor<PrintSExpression, void> {
     decIndent();
   }
   void visitIf(If *curr) {
-    printOpening(o, curr->ifFalse ? "if_else" : "if");
+    printOpening(o, "if");
     incIndent();
     printFullLine(curr->condition);
-    printFullLine(curr->ifTrue);
-    if (curr->ifFalse) printFullLine(curr->ifFalse);
+    // ifTrue and False have implict blocks, avoid printing them if possible
+    if (curr->ifTrue->is<Block>() && curr->ifTrue->dyn_cast<Block>()->name.isNull() && curr->ifTrue->dyn_cast<Block>()->list.size() == 1) {
+      printFullLine(curr->ifTrue->dyn_cast<Block>()->list.back());
+    } else {
+      printFullLine(curr->ifTrue);
+    }
+    if (curr->ifFalse) {
+      if (curr->ifFalse->is<Block>() && curr->ifFalse->dyn_cast<Block>()->name.isNull() && curr->ifFalse->dyn_cast<Block>()->list.size() == 1) {
+        printFullLine(curr->ifFalse->dyn_cast<Block>()->list.back());
+      } else {
+        printFullLine(curr->ifFalse);
+      }
+    }
     decIndent();
   }
   void visitLoop(Loop *curr) {
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index f0745f63f..381a57bb8 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -29,6 +29,7 @@
 #include "shared-constants.h"
 #include "parsing.h"
 #include "asm_v_wasm.h"
+#include "ast_utils.h"
 
 namespace wasm {
 
@@ -789,9 +790,32 @@ private:
   Expression* makeIf(Element& s) {
     auto ret = allocator.alloc<If>();
     ret->condition = parseExpression(s[1]);
-    ret->ifTrue = parseExpression(s[2]);
+    // ifTrue and ifFalse may get implicit blocks
+    Name ifTrueName = getPrefixedName("if-true");
+    labelStack.push_back(ifTrueName);
+    auto* ifTrue = parseExpression(s[2]);
+    labelStack.pop_back();
+    if (BreakSeeker::has(ifTrue, ifTrueName)) {
+      auto* block = allocator.alloc<Block>();
+      block->name = ifTrueName;
+      block->list.push_back(ifTrue);
+      block->finalize();
+      ifTrue = block;
+    }
+    ret->ifTrue = ifTrue;
     if (s.size() == 4) {
-      ret->ifFalse = parseExpression(s[3]);
+      Name ifFalseName = getPrefixedName("if-false");
+      labelStack.push_back(ifFalseName);
+      auto* ifFalse = parseExpression(s[3]);
+      labelStack.pop_back();
+      if (BreakSeeker::has(ifFalse, ifFalseName)) {
+        auto* block = allocator.alloc<Block>();
+        block->name = ifFalseName;
+        block->list.push_back(ifFalse);
+        block->finalize();
+        ifFalse = block;
+      }
+      ret->ifFalse = ifFalse;
       ret->finalize();
     }
     return ret;