[wasm] Dont compute global offsets if the module had errors (e.g. invalid memory type for global).

R=ahaas@chromium.org,bradnelson@chromium.org
BUG=chromium:617884

Review-Url: https://codereview.chromium.org/2044833002
Cr-Commit-Position: refs/heads/master@{#36779}

src/wasm/module-decoder.cc

@@ -384,7 +384,7 @@ class ModuleDecoder : public Decoder {
     }
 
   done:
-    CalculateGlobalsOffsets(module);
+    if (ok()) CalculateGlobalsOffsets(module);
     const WasmModule* finished_module = module;
     ModuleResult result = toResult(finished_module);
     if (FLAG_dump_wasm_module) {

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

@@ -201,6 +201,21 @@ TEST_F(WasmModuleVerifyTest, OneGlobal) {
   EXPECT_OFF_END_FAILURE(data, 1, sizeof(data));
 }
 
+TEST_F(WasmModuleVerifyTest, Global_invalid_type) {
+  static const byte data[] = {
+      SECTION(GLOBALS, 5),  // --
+      1,
+      NAME_LENGTH(1),
+      'g',  // name
+      64,   // invalid memory type
+      0,    // exported
+  };
+
+  ModuleResult result = DecodeModuleNoHeader(data, data + sizeof(data));
+  EXPECT_FALSE(result.ok());
+  if (result.val) delete result.val;
+}
+
 TEST_F(WasmModuleVerifyTest, ZeroGlobals) {
   static const byte data[] = {
       SECTION(GLOBALS, 1),  // --