[Asm.js] Prevents assignments to immutables.

test/cctest/asmjs/test-asm-typer.cc

Index: test/cctest/asmjs/test-asm-typer.cc
diff --git a/test/cctest/asmjs/test-asm-typer.cc b/test/cctest/asmjs/test-asm-typer.cc
index bf8615e00790d41fc6064a186f7e844b3b70817c..9182d16f661c72841581017d9d599bcc2bf91ab6 100644
--- a/test/cctest/asmjs/test-asm-typer.cc
+++ b/test/cctest/asmjs/test-asm-typer.cc
@@ -1941,4 +1941,62 @@ TEST(B63099) {
   }
 }
 
+// This issue was triggered because assignment to special symbosl (i.e., the

[titzer, 2016/08/23 13:58:25]

s/assignment to special symbosl/a special symbol/

[John, 2016/08/23 14:02:32]

I rephrased slightly differently: intead of "special" I called them "immutable."
let me know.

+// module's name, or any of the asm.js' module parameters) was assigned to.
+TEST(B640194) {
+  const char* kTests[] = {
+      "function asm() {\n"
+      "  'use asm';\n"
+      "  function f() {\n"
+      "    asm = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+      "function asm(stdlib) {\n"
+      "  'use asm';\n"
+      "  function f() {\n"
+      "    stdlib = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+      "function asm(stdlib, foreign) {\n"
+      "  'use asm';\n"
+      "  function f() {\n"
+      "    foreign = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+      "function asm(stdlib, foreign, heap) {\n"
+      "  'use asm';\n"
+      "  function f() {\n"
+      "    heap = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+      "function asm(stdlib, foreign, heap) {\n"
+      "  'use asm';\n"
+      "  var f = stdlib.Math.fround;\n"
+      "  function f() {\n"
+      "    f = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+      "function asm(stdlib, foreign, heap) {\n"
+      "  'use asm';\n"
+      "  var E = stdlib.Math.E;\n"
+      "  function f() {\n"
+      "    E = 0;\n"
+      "  }\n"
+      "  return f;\n"
+      "}",
+  };
+  for (size_t ii = 0; ii < arraysize(kTests); ++ii) {
+    if (!ValidationOf(Module(kTests[ii]))
+             ->FailsWithMessage("Can't assign to immutable symbol")) {
+      std::cerr << "Test:\n" << kTests[ii];
+      CHECK(false);
+    }
+  }
+}
+
 }  // namespace