Generate JS operators using helper functions with thunks for operands.

lib/compiler/implementation/ssa/codegen_helpers.dart

Index: lib/compiler/implementation/ssa/codegen_helpers.dart
diff --git a/lib/compiler/implementation/ssa/codegen_helpers.dart b/lib/compiler/implementation/ssa/codegen_helpers.dart
index 4344721da0b14d7f8ad8f767a296dbf9ed10fc3e..e965cfa2a31eac42faf7df333ee8db24e93fffa5 100644
--- a/lib/compiler/implementation/ssa/codegen_helpers.dart
+++ b/lib/compiler/implementation/ssa/codegen_helpers.dart
@@ -341,6 +341,10 @@ class JSPrecedence {
                                             SHIFT_PRECEDENCE),
     ">=" : const JSBinaryOperatorPrecedence(RELATIONAL_PRECEDENCE,
                                             SHIFT_PRECEDENCE),
+    "in": const JSBinaryOperatorPrecedence(RELATIONAL_PRECEDENCE,
+                                           SHIFT_PRECEDENCE),
+    "instanceof": const JSBinaryOperatorPrecedence(RELATIONAL_PRECEDENCE,
+                                                   SHIFT_PRECEDENCE),
     "<<" : const JSBinaryOperatorPrecedence(SHIFT_PRECEDENCE,
                                             ADDITIVE_PRECEDENCE),
     ">>" : const JSBinaryOperatorPrecedence(SHIFT_PRECEDENCE,
@@ -357,6 +361,21 @@ class JSPrecedence {
                                            PREFIX_PRECEDENCE),
     "%" : const JSBinaryOperatorPrecedence(MULTIPLICATIVE_PRECEDENCE,
                                            PREFIX_PRECEDENCE),
+    // TODO(lrn): Consider changing rhs to EXPRESSION_PRECEDENCE.
+    ",": const JSBinaryOperatorPrecedence(EXPRESSION_PRECEDENCE,
+                                          ASSIGNMENT_PRECEDENCE),
+    "=" : const JSAssignmentOperatorPrecedence(),
+    "+=" : const JSAssignmentOperatorPrecedence(),
+    "-=" : const JSAssignmentOperatorPrecedence(),
+    "*=" : const JSAssignmentOperatorPrecedence(),
+    "/=" : const JSAssignmentOperatorPrecedence(),
+    "%=" : const JSAssignmentOperatorPrecedence(),
+    "&=" : const JSAssignmentOperatorPrecedence(),
+    "|=" : const JSAssignmentOperatorPrecedence(),
+    "^=" : const JSAssignmentOperatorPrecedence(),
+    "<<=" : const JSAssignmentOperatorPrecedence(),
+    ">>=" : const JSAssignmentOperatorPrecedence(),
+    ">>>=" : const JSAssignmentOperatorPrecedence(),
   };
 }
 
@@ -364,6 +383,16 @@ class JSBinaryOperatorPrecedence {
   final int left;
   final int right;
   const JSBinaryOperatorPrecedence(this.left, this.right);
-  // All binary operators (excluding assignment) are left associative.
+  // All non-assignment binary operators are left associative.
   int get precedence() => left;
 }
+
+class JSAssignmentOperatorPrecedence implements JSBinaryOperatorPrecedence {
+  const JSAssignmentOperatorPrecedence();
+  // The actual left-hand-side of an assignment in JavaScript is the production
+  // 'LeftHandSideExpression ::= callExpression | newExpression'. We don't
+  // represent 'newExpression' at all.
+  int get left() => JSPrecedence.CALL_PRECEDENCE;
+  int get right() => JSPrecedence.ASSIGNMENT_PRECEDENCE;
+  int get precedence() => JSPrecedence.ASSIGNMENT_PRECEDENCE;
+}