[wasm] Only immutable imported globals are valid initializer expressions

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

Index: test/unittests/wasm/module-decoder-unittest.cc
diff --git a/test/unittests/wasm/module-decoder-unittest.cc b/test/unittests/wasm/module-decoder-unittest.cc
index f254358fc90dfbb8923d199289eca95ff0f57cdd..71feaff95a39319e580dbead26822b8958f72bd8 100644
--- a/test/unittests/wasm/module-decoder-unittest.cc
+++ b/test/unittests/wasm/module-decoder-unittest.cc
@@ -417,6 +417,100 @@ TEST_F(WasmModuleVerifyTest, MultipleSignatures) {
   EXPECT_OFF_END_FAILURE(data, 1, sizeof(data));
 }
 
+TEST_F(WasmModuleVerifyTest, DataSegmentWithImmutableImportedGlobal) {
+  // Import 2 globals so that we can initialize data with a global index != 0.
+  const byte data[] = {
+      SECTION(Import, 15),  // section header
+      2,                    // number of imports
+      NAME_LENGTH(1),       // --
+      'm',                  // module name
+      NAME_LENGTH(1),       // --
+      'f',                  // global name
+      kExternalGlobal,      // import kind
+      kLocalI32,            // type
+      0,                    // mutability
+      NAME_LENGTH(1),       // --
+      'n',                  // module name
+      NAME_LENGTH(1),       // --
+      'g',                  // global name
+      kExternalGlobal,      // import kind
+      kLocalI32,            // type
+      0,                    // mutability
+      SECTION(Memory, 4),
+      ENTRY_COUNT(1),
+      kResizableMaximumFlag,
+      28,
+      28,
+      SECTION(Data, 9),
+      ENTRY_COUNT(1),
+      LINEAR_MEMORY_INDEX_0,
+      WASM_INIT_EXPR_GLOBAL(1),  // dest addr
+      U32V_1(3),                 // source size
+      'a',
+      'b',
+      'c'  // data bytes
+  };
+  ModuleResult result = DecodeModule(data, data + sizeof(data));
+  EXPECT_OK(result);
+  WasmInitExpr expr = result.val->data_segments.back().dest_addr;
+  EXPECT_EQ(WasmInitExpr::kGlobalIndex, expr.kind);
+  EXPECT_EQ(1, expr.val.global_index);
+  if (result.val) delete result.val;
+}
+
+TEST_F(WasmModuleVerifyTest, DataSegmentWithMutableImportedGlobal) {
+  // Only an immutable imported global can be used as an init_expr.
+  const byte data[] = {
+      SECTION(Import, 8),  // section header
+      1,                   // number of imports
+      NAME_LENGTH(1),      // --
+      'm',                 // module name
+      NAME_LENGTH(1),      // --
+      'f',                 // global name
+      kExternalGlobal,     // import kind
+      kLocalI32,           // type
+      1,                   // mutability
+      SECTION(Memory, 4),
+      ENTRY_COUNT(1),
+      kResizableMaximumFlag,
+      28,
+      28,
+      SECTION(Data, 9),
+      ENTRY_COUNT(1),
+      LINEAR_MEMORY_INDEX_0,
+      WASM_INIT_EXPR_GLOBAL(0),  // dest addr
+      U32V_1(3),                 // source size
+      'a',
+      'b',
+      'c'  // data bytes
+  };
+  EXPECT_FAILURE(data);
+}
+TEST_F(WasmModuleVerifyTest, DataSegmentWithImmutableGlobal) {
+  // Only an immutable imported global can be used as an init_expr.
+  const byte data[] = {
+      SECTION(Memory, 4),
+      ENTRY_COUNT(1),
+      kResizableMaximumFlag,
+      28,
+      28,
+      SECTION(Global, 8),  // --
+      1,
+      kLocalI32,                       // local type
+      0,                               // immutable
+      WASM_INIT_EXPR_I32V_3(0x9bbaa),  // init
+      SECTION(Data, 9),
+      ENTRY_COUNT(1),
+      LINEAR_MEMORY_INDEX_0,
+      WASM_INIT_EXPR_GLOBAL(0),  // dest addr
+      U32V_1(3),                 // source size
+      'a',
+      'b',
+      'c'  // data bytes
+  };
+  EXPECT_FAILURE(data);
+}
+
 TEST_F(WasmModuleVerifyTest, OneDataSegment) {
   const byte kDataSegmentSourceOffset = 24;
   const byte data[] = {
@@ -1378,13 +1472,6 @@ TEST_F(WasmModuleVerifyTest, InitExpr_illegal) {
   EXPECT_INIT_EXPR_FAIL(WASM_IF_ELSE(WASM_ZERO, WASM_ZERO, WASM_ZERO));
 }
 
-TEST_F(WasmModuleVerifyTest, InitExpr_global) {
-  static const byte data[] = {WASM_INIT_EXPR_GLOBAL(37)};
-  WasmInitExpr expr = DecodeWasmInitExprForTesting(data, data + sizeof(data));
-  EXPECT_EQ(WasmInitExpr::kGlobalIndex, expr.kind);
-  EXPECT_EQ(37, expr.val.global_index);
-}
-
 TEST_F(WasmModuleVerifyTest, Multiple_Named_Sections) {
   static const byte data[] = {
       SECTION(Unknown, 4), 1, 'X', 17,  18,                      // --