[wasm] Rename "initializer" expression to "constant"

Change-Id: I6f2e5fa04eba1b3c97212be945b776ebc2be5915
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3726210Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81399}

src/wasm/function-body-decoder-impl.h

@@ -1366,14 +1366,13 @@ class WasmDecoder : public Decoder {
     if (decoding_mode == kConstantExpression) {
       if (!VALIDATE(!imm.global->mutability)) {
         this->DecodeError(pc,
-                          "mutable globals cannot be used in initializer "
+                          "mutable globals cannot be used in constant "
                           "expressions");
         return false;
       }
       if (!VALIDATE(imm.global->imported || this->enabled_.has_gc())) {
         this->DecodeError(
-            pc,
-            "non-imported globals cannot be used in initializer expressions");
+            pc, "non-imported globals cannot be used in constant expressions");
         return false;
       }
     }
@@ -3691,7 +3690,7 @@ class WasmFullDecoder : public WasmDecoder<validate, decoding_mode> {
 #undef DECODE
 
   static int NonConstError(WasmFullDecoder* decoder, WasmOpcode opcode) {
-    decoder->DecodeError("opcode %s is not allowed in init. expressions",
+    decoder->DecodeError("opcode %s is not allowed in constant expressions",
                          WasmOpcodes::OpcodeName(opcode));
     return 0;
   }
@@ -4094,9 +4093,9 @@ class WasmFullDecoder : public WasmDecoder<validate, decoding_mode> {
 
   uint32_t DecodeSimdOpcode(WasmOpcode opcode, uint32_t opcode_length) {
     if (decoding_mode == kConstantExpression) {
-      // Currently, only s128.const is allowed in initializer expressions.
+      // Currently, only s128.const is allowed in constant expressions.
       if (opcode != kExprS128Const) {
-        this->DecodeError("opcode %s is not allowed in init. expressions",
+        this->DecodeError("opcode %s is not allowed in constant expressions",
                           this->SafeOpcodeNameAt(this->pc()));
         return 0;
       }
@@ -4248,7 +4247,7 @@ class WasmFullDecoder : public WasmDecoder<validate, decoding_mode> {
 
 #define NON_CONST_ONLY                                                    \
   if (decoding_mode == kConstantExpression) {                             \
-    this->DecodeError("opcode %s is not allowed in init. expressions", \
+    this->DecodeError("opcode %s is not allowed in constant expressions", \
                       this->SafeOpcodeNameAt(this->pc()));                \
     return 0;                                                             \
   }
@@ -5825,11 +5824,9 @@ class WasmFullDecoder : public WasmDecoder<validate, decoding_mode> {
   bool TypeCheckStackAgainstMerge(uint32_t drop_values, Merge<Value>* merge) {
     static_assert(validate, "Call this function only within VALIDATE");
     constexpr const char* merge_description =
-        merge_type == kBranchMerge
-            ? "branch"
-            : merge_type == kReturnMerge
-                  ? "return"
-                  : merge_type == kInitExprMerge ? "init. expression"
+        merge_type == kBranchMerge     ? "branch"
+        : merge_type == kReturnMerge   ? "return"
+        : merge_type == kInitExprMerge ? "constant expression"
                                        : "fallthru";
     uint32_t arity = merge->arity;
     uint32_t actual = stack_size() - control_.back().stack_depth;

src/wasm/module-decoder.cc

@@ -1682,7 +1682,7 @@ class ModuleDecoderImpl : public Decoder {
   WasmError intermediate_error_;
   ModuleOrigin origin_;
   AccountingAllocator allocator_;
-  Zone init_expr_zone_{&allocator_, "initializer expression zone"};
+  Zone init_expr_zone_{&allocator_, "constant expr. zone"};
 
   bool has_seen_unordered_section(SectionCode section_code) {
     return seen_unordered_sections_ & (1 << section_code);
@@ -1943,7 +1943,7 @@ class ModuleDecoderImpl : public Decoder {
 #define TYPE_CHECK(found)                                                \
   if (V8_UNLIKELY(!IsSubtypeOf(found, expected, module_.get()))) {       \
     errorf(pc() + 1,                                                     \
-           "type error in init. expression[0] (expected %s, got %s)", \
+           "type error in constant expression[0] (expected %s, got %s)", \
            expected.name().c_str(), found.name().c_str());               \
     return {};                                                           \
   }
@@ -2027,7 +2027,7 @@ class ModuleDecoderImpl : public Decoder {
     }
 
     if (!decoder.interface().end_found()) {
-      error("Initializer expression is missing 'end'");
+      error("constant expression is missing 'end'");
       return {};
     }
 
@@ -2153,7 +2153,7 @@ class ModuleDecoderImpl : public Decoder {
     // - for non-active tables, whether the table is declarative (vs. passive).
     constexpr uint8_t kHasTableIndexOrIsDeclarativeMask = 1 << 1;
     // The mask for the bit in the flag which indicates if the functions of this
-    // segment are defined as function indices (0) or init. expressions (1).
+    // segment are defined as function indices (0) or constant expressions (1).
     constexpr uint8_t kExpressionsAsElementsMask = 1 << 2;
     constexpr uint8_t kFullMask = kNonActiveMask |
                                   kHasTableIndexOrIsDeclarativeMask |

src/wasm/module-instantiate.cc

@@ -445,7 +445,7 @@ InstanceBuilder::InstanceBuilder(Isolate* isolate,
       module_object_(module_object),
       ffi_(ffi),
       memory_buffer_(memory_buffer),
-      init_expr_zone_(isolate_->allocator(), "init. expression zone") {
+      init_expr_zone_(isolate_->allocator(), "constant expression zone") {
   sanitized_imports_.reserve(module_->import_table.size());
 }
 

src/wasm/wasm-init-expr.h

@@ -21,9 +21,9 @@ namespace wasm {
 struct WasmModule;
 class WasmFeatures;
 
-// Representation of an initializer expression. Unlike {ConstantExpression} in
-// wasm-module.h, this does not use {WireBytesRef}, i.e., it does not depend on
-// a wasm module's bytecode representation.
+// Representation of an constant expression. Unlike {ConstantExpression}, this
+// does not use {WireBytesRef}, i.e., it does not depend on a wasm module's
+// bytecode representation.
 class WasmInitExpr : public ZoneObject {
  public:
   enum Operator {

src/wasm/wasm-module-builder.cc

@@ -880,7 +880,7 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer* buffer) const {
 
     for (auto segment : data_segments_) {
       buffer->write_u8(0);              // linear memory segment
-      buffer->write_u8(kExprI32Const);  // initializer expression for dest
+      buffer->write_u8(kExprI32Const);  // constant expression for dest
       buffer->write_u32v(segment.dest);
       buffer->write_u8(kExprEnd);
       buffer->write_u32v(static_cast<uint32_t>(segment.data.size()));

test/fuzzer/wasm-fuzzer-common.cc

@@ -292,9 +292,9 @@ std::ostream& operator<<(std::ostream& os, const PrintName& name) {
   return os.put('\'').write(name.name.begin(), name.name.size()).put('\'');
 }
 
-// An interface for WasmFullDecoder used to decode initializer expressions. As
+// An interface for WasmFullDecoder used to decode constant expressions. As
 // opposed to the one in src/wasm/, this emits {WasmInitExpr} as opposed to a
-// {WasmValue}.
+// {ConstantExpression} (which evaluates to {WasmValue}).
 class InitExprInterface {
  public:
   static constexpr Decoder::ValidateFlag validate = Decoder::kFullValidation;
@@ -439,7 +439,7 @@ class InitExprInterface {
   Zone* zone_;
 };
 
-// Appends an initializer expression encoded in {wire_bytes}, in the offset
+// Appends an constant expression encoded in {wire_bytes}, in the offset
 // contained in {expr}.
 void AppendInitExpr(std::ostream& os, const WasmInitExpr& expr) {
   os << "WasmInitExpr.";
@@ -572,7 +572,7 @@ void GenerateTestCase(Isolate* isolate, ModuleWireBytes wire_bytes,
   CHECK_NOT_NULL(module);
 
   AccountingAllocator allocator;
-  Zone zone(&allocator, "init. expression zone");
+  Zone zone(&allocator, "constant expression zone");
 
   StdoutStream os;
 

test/mjsunit/wasm/element-segments-with-reftypes.js

@@ -107,5 +107,5 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
     () => builder.instantiate({m : {g :
         new WebAssembly.Global({value: "anyfunc", mutable: true}, null)}}),
     WebAssembly.CompileError,
-    /mutable globals cannot be used in initializer expressions/);
+    /mutable globals cannot be used in constant expressions/);
 })();

test/mjsunit/wasm/indirect-tables.js

@@ -914,5 +914,5 @@ function js_div(a, b) { return (a / b) | 0; }
 
   assertThrows(
     () => builder.instantiate(), WebAssembly.CompileError,
-    /non-imported globals cannot be used in initializer expressions/);
+    /non-imported globals cannot be used in constant expressions/);
 })();

test/mjsunit/wasm/wasm-module-builder.js

@@ -1534,9 +1534,9 @@ class WasmModuleBuilder {
     this.exports.push({name: name, kind: kExternalMemory, index: 0});
   }
 
-  // {offset} is an initializer expression.
+  // {offset} is a constant expression.
   // If {type} is undefined, then {elements} are function indices. Otherwise,
-  // they are initializer expressions.
+  // they are constant expressions.
   addActiveElementSegment(table, offset, elements, type) {
     checkExpr(offset);
     if (type != undefined) {
@@ -1548,7 +1548,7 @@ class WasmModuleBuilder {
   }
 
   // If {type} is undefined, then {elements} are function indices. Otherwise,
-  // they are initializer expressions.
+  // they are constant expressions.
   addPassiveElementSegment(elements, type) {
     if (type != undefined) {
       for (let element of elements) checkExpr(element);
@@ -1559,7 +1559,7 @@ class WasmModuleBuilder {
   }
 
   // If {type} is undefined, then {elements} are function indices. Otherwise,
-  // they are initializer expressions.
+  // they are constant expressions.
   addDeclarativeElementSegment(elements, type) {
     if (type != undefined) {
       for (let element of elements) checkExpr(element);

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

@@ -510,7 +510,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
   };
   EXPECT_FAILURE_WITH_MSG(
       no_initializer,
-      "expected 1 elements on the stack for init. expression, found 0");
+      "expected 1 elements on the stack for constant expression, found 0");
 
   static const byte too_many_initializers_no_end[] = {
       SECTION(Global,           // --
@@ -521,7 +521,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
               WASM_I32V_1(43))  // another value is too much
   };
   EXPECT_FAILURE_WITH_MSG(too_many_initializers_no_end,
-                          "Initializer expression is missing 'end'");
+                          "constant expression is missing 'end'");
 
   static const byte too_many_initializers[] = {
       SECTION(Global,           // --
@@ -533,7 +533,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
               kExprEnd)};
   EXPECT_FAILURE_WITH_MSG(
       too_many_initializers,
-      "expected 1 elements on the stack for init. expression, found 2");
+      "expected 1 elements on the stack for constant expression, found 2");
 
   static const byte missing_end_opcode[] = {
       SECTION(Global,           // --
@@ -543,7 +543,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
               WASM_I32V_1(42))  // init value
   };
   EXPECT_FAILURE_WITH_MSG(missing_end_opcode,
-                          "Initializer expression is missing 'end'");
+                          "constant expression is missing 'end'");
 
   static const byte referencing_out_of_bounds_global[] = {
       SECTION(Global, ENTRY_COUNT(1),         // --
@@ -596,7 +596,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
   };
   EXPECT_FAILURE_WITH_MSG(
       referencing_mutable_global,
-      "mutable globals cannot be used in initializer expressions");
+      "mutable globals cannot be used in constant expressions");
 
   static const byte referencing_mutable_imported_global[] = {
       SECTION(Import, ENTRY_COUNT(1),          // --
@@ -611,7 +611,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
   };
   EXPECT_FAILURE_WITH_MSG(
       referencing_mutable_imported_global,
-      "mutable globals cannot be used in initializer expressions");
+      "mutable globals cannot be used in constant expressions");
 
   static const byte referencing_immutable_imported_global[] = {
       SECTION(Import, ENTRY_COUNT(1),          // --
@@ -637,7 +637,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
   };
   EXPECT_FAILURE_WITH_MSG(
       referencing_local_global,
-      "non-imported globals cannot be used in initializer expressions");
+      "non-imported globals cannot be used in constant expressions");
 
   {
     // But: experimental-wasm-gc should enable referencing immutable local
@@ -647,7 +647,7 @@ TEST_F(WasmModuleVerifyTest, GlobalInitializer) {
     // Referencing mutable glocals still invalid.
     EXPECT_FAILURE_WITH_MSG(
         referencing_mutable_global,
-        "mutable globals cannot be used in initializer expressions");
+        "mutable globals cannot be used in constant expressions");
   }
 }
 
@@ -811,7 +811,7 @@ TEST_F(WasmModuleVerifyTest, RttCanonGlobalTypeError) {
   ModuleResult result = DecodeModule(data, data + sizeof(data));
   EXPECT_NOT_OK(
       result,
-      "type error in init. expression[0] (expected (rtt 0), got (rtt 1))");
+      "type error in constant expression[0] (expected (rtt 0), got (rtt 1))");
 }
 
 TEST_F(WasmModuleVerifyTest, StructNewInitExpr) {
@@ -848,7 +848,7 @@ TEST_F(WasmModuleVerifyTest, StructNewInitExpr) {
               WASM_INIT_EXPR_STRUCT_NEW(0, WASM_I32V(42), WASM_RTT_CANON(0)))};
   EXPECT_FAILURE_WITH_MSG(
       type_error,
-      "type error in init. expression[0] (expected (ref 1), got (ref 0))");
+      "type error in constant expression[0] (expected (ref 1), got (ref 0))");
 
   static const byte subexpr_type_error[] = {
       SECTION(Type, ENTRY_COUNT(2),  // --
@@ -902,7 +902,7 @@ TEST_F(WasmModuleVerifyTest, ArrayNewFixedInitExpr) {
                                              WASM_RTT_CANON(0)))};
   EXPECT_FAILURE_WITH_MSG(
       type_error,
-      "type error in init. expression[0] (expected (ref 1), got (ref 0))");
+      "type error in constant expression[0] (expected (ref 1), got (ref 0))");
 
   static const byte subexpr_type_error[] = {
       SECTION(Type, ENTRY_COUNT(1), WASM_ARRAY_DEF(kI64Code, true)),
@@ -1208,7 +1208,7 @@ TEST_F(WasmModuleVerifyTest, TypeCanonicalization) {
       SECTION(Global,                          // --
               ENTRY_COUNT(1), kRefCode, 0, 0,  // Type, mutability
               WASM_ARRAY_NEW_FIXED_STATIC(1, 1, WASM_I32V(10)),
-              kExprEnd)  // Init. expression
+              kExprEnd)  // initial value
   };
 
   // Global initializer should verify as identical type in other group
@@ -1225,13 +1225,13 @@ TEST_F(WasmModuleVerifyTest, TypeCanonicalization) {
       SECTION(Global,                          // --
               ENTRY_COUNT(1), kRefCode, 0, 0,  // Type, mutability
               WASM_ARRAY_NEW_FIXED_STATIC(1, 1, WASM_I32V(10)),
-              kExprEnd)  // Init. expression
+              kExprEnd)  // initial value
   };
 
   // Global initializer should not verify as type in distinct rec. group.
   EXPECT_FAILURE_WITH_MSG(
       non_identical_group,
-      "type error in init. expression[0] (expected (ref 0), got (ref 1))");
+      "type error in constant expression[0] (expected (ref 0), got (ref 1))");
 }
 
 TEST_F(WasmModuleVerifyTest, ZeroExceptions) {
@@ -2036,7 +2036,7 @@ TEST_F(WasmModuleVerifyTest, ElementSectionInitFuncRefTableWithExternRefNull) {
 
   EXPECT_FAILURE_WITH_MSG(
       data,
-      "type error in init. expression[0] (expected funcref, got externref)");
+      "type error in constant expression[0] (expected funcref, got externref)");
 }
 
 TEST_F(WasmModuleVerifyTest, ElementSectionDontInitExternRefImportedTable) {
@@ -2089,7 +2089,7 @@ TEST_F(WasmModuleVerifyTest, ElementSectionGlobalGetOutOfBounds) {
               0x05,            // Mode: Passive with expressions-as-elements
               kFuncRefCode,    // type
               ENTRY_COUNT(1),  // element count
-              kExprGlobalGet, 0x00, kExprEnd)};  // init. expression
+              kExprGlobalGet, 0x00, kExprEnd)};  // initial value
   EXPECT_FAILURE_WITH_MSG(data, "Invalid global index: 0");
 }
 
@@ -2104,8 +2104,8 @@ TEST_F(WasmModuleVerifyTest, ExtendedConstantsFail) {
               // initializer
               kExprGlobalGet, 0x00, kExprGlobalGet, 0x00, kExprI32Add,
               kExprEnd)};
-  EXPECT_FAILURE_WITH_MSG(data,
-                          "opcode i32.add is not allowed in init. expressions");
+  EXPECT_FAILURE_WITH_MSG(
+      data, "opcode i32.add is not allowed in constant expressions");
 }
 
 TEST_F(WasmModuleVerifyTest, ExtendedConstantsI32) {
@@ -2273,7 +2273,7 @@ TEST_F(WasmModuleVerifyTest, NonNullableTable) {
               ENTRY_COUNT(1),                        // 1 table
               kRefCode, 0,                           // table 0: type
               0, 10,                                 // table 0: limits
-              kExprRefFunc, 0, kExprEnd),  // table 0: init. expression
+              kExprRefFunc, 0, kExprEnd),            // table 0: initial value
       SECTION(Code, ENTRY_COUNT(1), NOP_BODY)};
   ModuleResult result = DecodeModule(data, data + sizeof(data));
   EXPECT_OK(result);