[wasm] ASM-2-WASM. Enforces switch default clause appearing last.

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

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cstring>
 #include <functional>
 #include <iostream>
 #include <memory>
 
 #include "src/asmjs/asm-typer.h"
@@ skipping 841 matching lines @@
     const char* error_message;
   } kTests[] = {
       {"if (fround(1));", "If condition must be type int"},
       {"return;", "Type mismatch in return statement"},
       {"return +1.0;", "Type mismatch in return statement"},
       {"return +d()", "Type mismatch in return statement"},
       {"while (fround(1));", "While condition must be type int"},
       {"do {} while (fround(1));", "Do {} While condition must be type int"},
       {"for (;fround(1););", "For condition must be type int"},
       {"switch(flocal){ case 0: return 0; }", "Switch tag must be signed"},
+      {"switch(slocal){ default: case 0: return 0; }",
+       "Switch default must appear last"},
       {"switch(slocal){ case 1: case 1: return 0; }", "Duplicated case label"},
       {"switch(slocal){ case 1: case 0: break; case 1: return 0; }",
        "Duplicated case label"},
       {"switch(slocal){ case 1.0: return 0; }",
        "Case label must be a 32-bit signed integer"},
       {"switch(slocal){ case 1.0: return 0; }",
        "Case label must be a 32-bit signed integer"},
       {"switch(slocal){ case -100000: case 2147483647: return 0; }",
        "Out-of-bounds case"},
       {"switch(slocal){ case 2147483648: return 0; }",
@@ skipping 919 matching lines @@
     const auto* test = kTests + ii;
     if (!ValidationOf(Module(test->module))
              ->FailsWithMessage(test->error_message)) {
       std::cerr << "Test:\n" << test->module;
       CHECK(false);
     }
   }
 }
 
 }  // namespace