[wasm] Fix OpcodeLength() calculation.

test/unittests/wasm/wasm-macro-gen-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/wasm-macro-gen.h"
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
 class WasmMacroGenTest : public TestWithZone {};
 
 #define EXPECT_SIZE(size, ...)     \
   do {                             \
     byte code[] = {__VA_ARGS__};   \
     EXPECT_EQ(size, sizeof(code)); \
   } while (false)
 
 
 TEST_F(WasmMacroGenTest, Constants) {
   EXPECT_SIZE(2, WASM_ONE);
   EXPECT_SIZE(2, WASM_ZERO);
 
   EXPECT_SIZE(2, WASM_I8(122));
   EXPECT_SIZE(2, WASM_I8(254));
 
   EXPECT_SIZE(2, WASM_I32V_1(1));
+  EXPECT_SIZE(3, WASM_I32V_2(200));
   EXPECT_SIZE(4, WASM_I32V_3(10000));
   EXPECT_SIZE(5, WASM_I32V_4(-9828934));
+  EXPECT_SIZE(6, WASM_I32V_5(-1119828934));

[Mircea Trofin, 2016/03/11 17:15:41]

Do these numbers mean anything? Should they be a const indicating their
semantics?

[titzer, 2016/03/11 17:17:35]

They're just random values with no semantic meaning. Factoring them out just
creates noise.

 
   EXPECT_SIZE(2, WASM_I64V_1(1));
+  EXPECT_SIZE(3, WASM_I64V_2(300));
   EXPECT_SIZE(4, WASM_I64V_3(10000));
   EXPECT_SIZE(5, WASM_I64V_4(-9828934));
+  EXPECT_SIZE(6, WASM_I64V_5(-1119828934));
   EXPECT_SIZE(10, WASM_I64V_9(0x123456789abcdef0ULL));
 
   EXPECT_SIZE(5, WASM_F32(1.0f));
   EXPECT_SIZE(5, WASM_F32(10000.0f));
   EXPECT_SIZE(5, WASM_F32(-9828934.0f));
 
   EXPECT_SIZE(9, WASM_F64(1.5));
   EXPECT_SIZE(9, WASM_F64(10200.0));
   EXPECT_SIZE(9, WASM_F64(-9818934.0));
 }
@@ skipping 269 matching lines @@
     EXPECT_SIZE(5, WASM_LOAD_MEM_OFFSET(kMemTypes[i], 11, WASM_ZERO));
   }
   for (size_t i = 0; i < arraysize(kMemTypes); i++) {
     EXPECT_SIZE(7, WASM_STORE_MEM_OFFSET(kMemTypes[i], 13, WASM_ZERO,
                                          WASM_GET_LOCAL(0)));
   }
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8