[wasm_builder] Remove array.new_data handling in global sections

As of 2025/05/14, `array.new_data` is not a constant instruction, so
can't be used in a global initializer.

Also, data count section needs to appear right before the code section.
Without `array.new_data` we don't need to generate it before the global
section.

Remove the code related to handling `array.new_data` in global sections.

When `array.new_data` becomes constant, we can generate the data count
section in its new place always, without having to specially handle it
when it's used in a global section.

Change-Id: If11824e171d7f21848e82c102f0a4e8257f02c6f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/366341
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Ömer Ağacan <omersa@google.com>

pkg/wasm_builder/lib/src/builder/global.dart

@@ -10,8 +10,7 @@ class GlobalBuilder extends ir.Global with IndexableBuilder<ir.DefinedGlobal> {
 
   GlobalBuilder(ModuleBuilder module, super.index, super.type,
       [super.globalName])
-      : initializer =
-            InstructionsBuilder(module, [type.type], isGlobalInitializer: true);
+      : initializer = InstructionsBuilder(module, [type.type]);
 
   @override
   ir.DefinedGlobal forceBuild() =>

pkg/wasm_builder/lib/src/builder/instructions.dart

@@ -104,9 +104,6 @@ class InstructionsBuilder with Builder<ir.Instructions> {
   /// Locals declared in this body, including parameters.
   final List<ir.Local> locals = [];
 
-  /// Is this the initializer of a global variable?
-  final bool isGlobalInitializer;
-
   /// Whether a textual trace of the instruction stream should be recorded when
   /// emitting instructions (provided asserts are enabled).
   ///
@@ -143,8 +140,7 @@ class InstructionsBuilder with Builder<ir.Instructions> {
   final Map<ir.Instruction, StackTrace>? _stackTraces;
 
   /// Create a new instruction sequence.
-  InstructionsBuilder(this.module, List<ir.ValueType> outputs,
-      {this.isGlobalInitializer = false})
+  InstructionsBuilder(this.module, List<ir.ValueType> outputs)
       : _stackTraces = module.watchPoints.isNotEmpty ? {} : null {
     _labelStack.add(Expression(const [], outputs));
   }
@@ -1076,7 +1072,6 @@ class InstructionsBuilder with Builder<ir.Instructions> {
         [ir.RefType.def(arrayType, nullable: false)],
         trace: ['array.new_data', arrayType, data.index]));
     _add(ir.ArrayNewData(arrayType, data));
-    if (isGlobalInitializer) module.dataReferencedFromGlobalInitializer = true;
   }
 
   /// Emit an `array.copy` instruction.

pkg/wasm_builder/lib/src/builder/module.dart

@@ -17,7 +17,6 @@ class ModuleBuilder with Builder<ir.Module> {
   final dataSegments = DataSegmentsBuilder();
   late final globals = GlobalsBuilder(this);
   final exports = ExportsBuilder();
-  bool dataReferencedFromGlobalInitializer = false;
 
   /// Create a new, initially empty, module.
   ///
@@ -47,7 +46,6 @@ class ModuleBuilder with Builder<ir.Module> {
             .followedBy(finalMemories.imported)
             .followedBy(finalGlobals.imported)
             .toList(),
-        watchPoints,
-        dataReferencedFromGlobalInitializer);
+        watchPoints);
   }
 }

pkg/wasm_builder/lib/src/ir/module.dart

@@ -17,7 +17,6 @@ class Module implements Serializable {
   final DataSegments dataSegments;
   final List<Import> imports;
   final List<int> watchPoints;
-  final bool dataReferencedFromGlobalInitializer;
 
   Module(
       this.functions,
@@ -29,8 +28,7 @@ class Module implements Serializable {
       this.types,
       this.dataSegments,
       this.imports,
-      this.watchPoints,
-      this.dataReferencedFromGlobalInitializer);
+      this.watchPoints);
 
   /// Serialize a module to its binary representation.
   @override
@@ -46,16 +44,11 @@ class Module implements Serializable {
     TableSection(tables.defined, watchPoints).serialize(s);
     MemorySection(memories.defined, watchPoints).serialize(s);
     TagSection(tags.defined, watchPoints).serialize(s);
-    if (dataReferencedFromGlobalInitializer) {
-      DataCountSection(dataSegments.defined, watchPoints).serialize(s);
-    }
     GlobalSection(globals.defined, watchPoints).serialize(s);
     ExportSection(exports.exported, watchPoints).serialize(s);
     StartSection(functions.start, watchPoints).serialize(s);
     ElementSection(tables.defined, watchPoints).serialize(s);
-    if (!dataReferencedFromGlobalInitializer) {
-      DataCountSection(dataSegments.defined, watchPoints).serialize(s);
-    }
+    DataCountSection(dataSegments.defined, watchPoints).serialize(s);
     CodeSection(functions.defined, watchPoints).serialize(s);
     DataSection(dataSegments.defined, watchPoints).serialize(s);
     if (functions.namedCount > 0 || types.namedCount > 0) {