[wasm] Support a two-level namespace for imports.

test/unittests/wasm/module-decoder-unittest.cc

 // Copyright 2015 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 "test/unittests/test-utils.h"
 
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-macro-gen.h"
 #include "src/wasm/wasm-opcodes.h"
 
@@ skipping 370 matching lines @@
   EXPECT_EQ(0, function->local_i64_count);
   EXPECT_EQ(0, function->local_f32_count);
   EXPECT_EQ(0, function->local_f64_count);
 
   EXPECT_FALSE(function->exported);
   EXPECT_TRUE(function->external);
 
   if (result.val) delete result.val;
 }
 
-
 TEST_F(WasmModuleVerifyTest, OneFunctionWithNopBody) {
   static const byte kCodeStartOffset = 19;
   static const byte kCodeEndOffset = kCodeStartOffset + 1;
 
   static const byte data[] = {
       kDeclSignatures, 1,
       // sig#0 -------------------------------------------------------
       0, 0,  // void -> void
       kDeclFunctions, 1,
       // func#0 ------------------------------------------------------
@@ skipping 686 matching lines @@
       VOID_VOID_SIG,
       kDeclImportTable,
       1,               // --
       SIG_INDEX(0),    // sig index
       NAME_OFFSET(1),  // module name
       NAME_OFFSET(1)   // function name
   };
   EXPECT_VERIFIES(data);
 }
 
+TEST_F(WasmModuleVerifyTest, ImportTable_invalid_module) {
+  static const byte data[] = {
+      kDeclSignatures,
+      1,
+      VOID_VOID_SIG,
+      kDeclImportTable,
+      1,               // --
+      SIG_INDEX(0),    // sig index
+      NAME_OFFSET(0),  // module name
+      NAME_OFFSET(1)   // function name
+  };
+  EXPECT_FAILURE(data);
+}
+
 TEST_F(WasmModuleVerifyTest, ImportTable_off_end) {
   static const byte data[] = {
       kDeclSignatures, 1, VOID_VOID_SIG, kDeclImportTable, 1,
       SIG_INDEX(0),    // sig index
       NAME_OFFSET(1),  // module name
       NAME_OFFSET(1),  // function name
   };
 
   EXPECT_OFF_END_FAILURE(data, 5, sizeof(data));
 }
@@ skipping 97 matching lines @@
   for (int length = 13; length < sizeof(data); length++) {
     ModuleResult result = DecodeModule(data, data + length);
     EXPECT_FALSE(result.ok());
     if (result.val) delete result.val;
   }
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8