[wasm] Improve init. expr. testing code

- Add an expected type argument in DecodeWasmInitExprForTesting. This
  eliminates the need to check for kWasmVoid in consume_init_expr.
- Invoke StartDecoding() to initialize module in
  DecodeWasmInitExprForTesting.
- Pass the current module to DecodeInitExprForTesting.
- Adjust tests.

Bug: v8:11895
Change-Id: I13b71b68a2011bf08742701cb9dd986afd6e55f8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972907
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75292}

src/wasm/module-decoder.cc

@@ -1385,8 +1385,8 @@ class ModuleDecoderImpl : public Decoder {
     return ok() ? result : nullptr;
   }
 
-  WasmInitExpr DecodeInitExprForTesting() {
-    return consume_init_expr(nullptr, kWasmVoid, 0);
+  WasmInitExpr DecodeInitExprForTesting(ValueType expected) {
+    return consume_init_expr(module_.get(), expected, 0);
   }
 
   const std::shared_ptr<WasmModule>& shared_module() const { return module_; }
@@ -2009,7 +2009,7 @@ class ModuleDecoderImpl : public Decoder {
     }
 
     WasmInitExpr expr = std::move(stack.back());
-    if (expected != kWasmVoid && !IsSubtypeOf(TypeOf(expr), expected, module)) {
+    if (!IsSubtypeOf(TypeOf(expr), expected, module)) {
       errorf(pc(), "type error in init expression, expected %s, got %s",
              expected.name().c_str(), TypeOf(expr).name().c_str());
     }
@@ -2449,10 +2449,12 @@ const FunctionSig* DecodeWasmSignatureForTesting(const WasmFeatures& enabled,
 }
 
 WasmInitExpr DecodeWasmInitExprForTesting(const WasmFeatures& enabled,
-                                          const byte* start, const byte* end) {
-  AccountingAllocator allocator;
+                                          const byte* start, const byte* end,
+                                          ValueType expected) {
   ModuleDecoderImpl decoder(enabled, start, end, kWasmOrigin);
-  return decoder.DecodeInitExprForTesting();
+  AccountingAllocator allocator;
+  decoder.StartDecoding(nullptr, &allocator);
+  return decoder.DecodeInitExprForTesting(expected);
 }
 
 FunctionResult DecodeWasmFunctionForTesting(

src/wasm/module-decoder.h

@@ -171,8 +171,9 @@ V8_EXPORT_PRIVATE FunctionResult DecodeWasmFunctionForTesting(
     const WasmModule* module, const byte* function_start,
     const byte* function_end, Counters* counters);
 
-V8_EXPORT_PRIVATE WasmInitExpr DecodeWasmInitExprForTesting(
-    const WasmFeatures& enabled, const byte* start, const byte* end);
+V8_EXPORT_PRIVATE WasmInitExpr
+DecodeWasmInitExprForTesting(const WasmFeatures& enabled, const byte* start,
+                             const byte* end, ValueType expected);
 
 struct CustomSectionOffset {
   WireBytesRef section;

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

@@ -3199,24 +3199,27 @@ class WasmInitExprDecodeTest : public TestWithZone {
 
   WasmFeatures enabled_features_;
 
-  WasmInitExpr DecodeInitExpr(const byte* start, const byte* end) {
-    return DecodeWasmInitExprForTesting(enabled_features_, start, end);
+  WasmInitExpr DecodeInitExpr(const byte* start, const byte* end,
+                              ValueType expected) {
+    return DecodeWasmInitExprForTesting(enabled_features_, start, end,
+                                        expected);
   }
 };
 
-#define EXPECT_INIT_EXPR(Type, type, value, ...)                   \
-  {                                                                \
-    static const byte data[] = {__VA_ARGS__, kExprEnd};            \
-    WasmInitExpr expr = DecodeInitExpr(data, data + sizeof(data)); \
-    EXPECT_EQ(WasmInitExpr::k##Type##Const, expr.kind());          \
-    EXPECT_EQ(value, expr.immediate().type##_const);               \
+#define EXPECT_INIT_EXPR(Type, type, value, ...)                \
+  {                                                             \
+    static const byte data[] = {__VA_ARGS__, kExprEnd};         \
+    WasmInitExpr expr =                                         \
+        DecodeInitExpr(data, data + sizeof(data), kWasm##Type); \
+    EXPECT_EQ(WasmInitExpr::k##Type##Const, expr.kind());       \
+    EXPECT_EQ(value, expr.immediate().type##_const);            \
   }
 
-#define EXPECT_INIT_EXPR_FAIL(...)                                 \
-  {                                                                \
-    static const byte data[] = {__VA_ARGS__, kExprEnd};            \
-    WasmInitExpr expr = DecodeInitExpr(data, data + sizeof(data)); \
-    EXPECT_EQ(WasmInitExpr::kNone, expr.kind());                   \
+#define EXPECT_INIT_EXPR_FAIL(value_type, ...)                                 \
+  {                                                                            \
+    static const byte data[] = {__VA_ARGS__, kExprEnd};                        \
+    WasmInitExpr expr = DecodeInitExpr(data, data + sizeof(data), value_type); \
+    EXPECT_EQ(WasmInitExpr::kNone, expr.kind());                               \
   }
 
 TEST_F(WasmInitExprDecodeTest, InitExpr_i32) {
@@ -3250,16 +3253,17 @@ TEST_F(WasmInitExprDecodeTest, InitExpr_f64) {
 TEST_F(WasmInitExprDecodeTest, InitExpr_ExternRef) {
   WASM_FEATURE_SCOPE(reftypes);
   static const byte data[] = {kExprRefNull, kExternRefCode, kExprEnd};
-  WasmInitExpr expr = DecodeInitExpr(data, data + sizeof(data));
+  WasmInitExpr expr = DecodeInitExpr(data, data + sizeof(data), kWasmExternRef);
   EXPECT_EQ(WasmInitExpr::kRefNullConst, expr.kind());
 }
 
 TEST_F(WasmInitExprDecodeTest, InitExpr_illegal) {
-  EXPECT_INIT_EXPR_FAIL(WASM_I32V_1(0), WASM_I32V_1(0));
-  EXPECT_INIT_EXPR_FAIL(WASM_LOCAL_GET(0));
-  EXPECT_INIT_EXPR_FAIL(WASM_LOCAL_SET(0, WASM_I32V_1(0)));
-  EXPECT_INIT_EXPR_FAIL(WASM_I32_ADD(WASM_I32V_1(0), WASM_I32V_1(0)));
-  EXPECT_INIT_EXPR_FAIL(WASM_IF_ELSE(WASM_ZERO, WASM_ZERO, WASM_ZERO));
+  EXPECT_INIT_EXPR_FAIL(kWasmI32, WASM_I32V_1(0), WASM_I32V_1(0));
+  EXPECT_INIT_EXPR_FAIL(kWasmI32, WASM_LOCAL_GET(0));
+  EXPECT_INIT_EXPR_FAIL(kWasmVoid, WASM_LOCAL_SET(0, WASM_I32V_1(0)));
+  EXPECT_INIT_EXPR_FAIL(kWasmI32, WASM_I32_ADD(WASM_I32V_1(0), WASM_I32V_1(0)));
+  EXPECT_INIT_EXPR_FAIL(kWasmI32,
+                        WASM_IF_ELSE(WASM_ZERO, WASM_ZERO, WASM_ZERO));
 }
 
 TEST_F(WasmModuleVerifyTest, Multiple_Named_Sections) {