[vm,dyn_modules] Support deferred libraries

TEST=ci

Change-Id: I0c9ba10b3220729aa9114ae965a4d3d2a4037a88
Cq-Include-Trybots: luci.dart.try:vm-aot-dyn-linux-debug-x64-try,vm-aot-dyn-linux-product-x64-try,vm-dyn-linux-debug-x64-try,vm-dyn-mac-debug-arm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/447761
Reviewed-by: Tess Strickland <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

Author: alexmarkov

pkg/dart2bytecode/docs/bytecode.md

@@ -805,6 +805,13 @@ type ConstantExternalCall extends ConstantPoolEntry {
 type ConstantFfiCall extends ConstantPoolEntry {
   Byte tag = 16;
 }
+
+type ConstantDeferredLibraryPrefix extends ConstantPoolEntry {
+  Byte tag = 17;
+  PackedObject name;
+  PackedObject enclosingLibrary;
+  PackedObject targetLibrary;
+}
 ```
 
 ### Exceptions table

pkg/dart2bytecode/lib/bytecode_generator.dart

@@ -909,9 +909,6 @@ class BytecodeGenerator extends RecursiveVisitor {
       libraryIndex.getTopLevelProcedure(
           'dart:_internal', '_boundsCheckForPartialInstantiation');
 
-  late Procedure futureValue =
-      libraryIndex.getProcedure('dart:async', 'Future', 'value');
-
   late Procedure throwLocalNotInitialized = libraryIndex.getProcedure(
       'dart:_internal', 'LateError', '_throwLocalNotInitialized');
 
@@ -931,6 +928,12 @@ class BytecodeGenerator extends RecursiveVisitor {
   late Procedure allocateInvocationMirror = libraryIndex.getProcedure(
       'dart:core', '_InvocationMirror', '_allocateInvocationMirror');
 
+  late Procedure loadLibrary =
+      libraryIndex.getTopLevelProcedure('dart:core', '_loadLibrary');
+
+  late Procedure checkLoaded =
+      libraryIndex.getTopLevelProcedure('dart:core', '_checkLoaded');
+
   late Procedure unsafeCast =
       libraryIndex.getTopLevelProcedure('dart:_internal', 'unsafeCast');
 
@@ -3704,19 +3707,22 @@ class BytecodeGenerator extends RecursiveVisitor {
       rhs is VariableGet ||
       rhs is AsExpression;
 
-  void _genFutureNull() {
-    asm.emitPushNull();
-    _genDirectCall(futureValue, objectTable.getArgDescHandle(1), 1);
-  }
-
   @override
   void visitLoadLibrary(LoadLibrary node) {
-    _genFutureNull();
+    final dependency = node.import;
+    assert(dependency.isDeferred);
+    asm.emitPushConstant(cp.addDeferredLibraryPrefix(dependency.name!,
+        dependency.enclosingLibrary, dependency.targetLibrary));
+    _genDirectCall(loadLibrary, objectTable.getArgDescHandle(1), 1);
   }
 
   @override
   void visitCheckLibraryIsLoaded(CheckLibraryIsLoaded node) {
-    _genFutureNull();
+    final dependency = node.import;
+    assert(dependency.isDeferred);
+    asm.emitPushConstant(cp.addDeferredLibraryPrefix(dependency.name!,
+        dependency.enclosingLibrary, dependency.targetLibrary));
+    _genDirectCall(checkLoaded, objectTable.getArgDescHandle(1), 1);
   }
 
   @override

pkg/dart2bytecode/lib/constant_pool.dart

@@ -32,6 +32,7 @@ enum ConstantTag {
   kDynamicCall,
   kExternalCall,
   kFfiCall,
+  kDeferredLibraryPrefix,
 }
 
 String constantTagToString(ConstantTag tag) =>
@@ -90,6 +91,8 @@ abstract class ConstantPoolEntry {
         return new ConstantExternalCall.read(reader);
       case ConstantTag.kFfiCall:
         return new ConstantFfiCall.read(reader);
+      case ConstantTag.kDeferredLibraryPrefix:
+        return new ConstantDeferredLibraryPrefix.read(reader);
     }
     throw 'Unexpected constant tag $tag';
   }
@@ -556,6 +559,45 @@ class ConstantFfiCall extends ConstantPoolEntry {
   bool operator ==(other) => identical(this, other);
 }
 
+class ConstantDeferredLibraryPrefix extends ConstantPoolEntry {
+  final ObjectHandle name;
+  final ObjectHandle enclosingLibrary;
+  final ObjectHandle targetLibrary;
+
+  ConstantDeferredLibraryPrefix(
+      this.name, this.enclosingLibrary, this.targetLibrary);
+
+  @override
+  ConstantTag get tag => ConstantTag.kDeferredLibraryPrefix;
+
+  @override
+  void writeValue(BufferedWriter writer) {
+    writer.writePackedObject(name);
+    writer.writePackedObject(enclosingLibrary);
+    writer.writePackedObject(targetLibrary);
+  }
+
+  ConstantDeferredLibraryPrefix.read(BufferedReader reader)
+      : name = reader.readPackedObject(),
+        enclosingLibrary = reader.readPackedObject(),
+        targetLibrary = reader.readPackedObject();
+
+  @override
+  String toString() =>
+      'DeferredLibraryPrefix $name, $enclosingLibrary -> $targetLibrary';
+
+  @override
+  int get hashCode => _combineHashes(name.hashCode,
+      _combineHashes(enclosingLibrary.hashCode, targetLibrary.hashCode));
+
+  @override
+  bool operator ==(other) =>
+      other is ConstantDeferredLibraryPrefix &&
+      this.name == other.name &&
+      this.enclosingLibrary == other.enclosingLibrary &&
+      this.targetLibrary == other.targetLibrary;
+}
+
 /// Reserved constant pool entry.
 class _ReservedConstantPoolEntry extends ConstantPoolEntry {
   const _ReservedConstantPoolEntry();
@@ -663,6 +705,14 @@ class ConstantPool {
 
   int addEmptyTypeArguments() => _add(const ConstantEmptyTypeArguments());
 
+  int addDeferredLibraryPrefix(
+          String name, Library enclosingLibrary, Library targetLibrary) =>
+      _add(ConstantDeferredLibraryPrefix(
+        objectTable.getConstStringHandle(name),
+        objectTable.getHandle(enclosingLibrary)!,
+        objectTable.getHandle(targetLibrary)!,
+      ));
+
   int addObjectRef(Node? node) {
     // Constant objects should not depend on the type parameters of
     // the enclosing function.

pkg/dart2bytecode/testcases/deferred_lib.dart.expect

@@ -14,17 +14,18 @@ Function 'callDeferred', static, reflectable, debuggable
 Bytecode {
   Entry                1
   CheckStack           0
-  PushNull
-  DirectCall           CP#0, 1
+  PushConstant         CP#0
+  DirectCall           CP#1, 1
   PopLocal             r0
-  DirectCall           CP#2, 0
+  DirectCall           CP#3, 0
   ReturnTOS
 }
 ConstantPool {
-  [0] = DirectCall 'dart:async::Future::value (constructor)', ArgDesc num-args 1, num-type-args 0, names []
-  [1] = Reserved
-  [2] = DirectCall 'DART_SDK/pkg/dart2bytecode/testcases/hello.dart::main', ArgDesc num-args 0, num-type-args 0, names []
-  [3] = Reserved
+  [0] = DeferredLibraryPrefix 'lib', DART_SDK/pkg/dart2bytecode/testcases/deferred_lib.dart -> DART_SDK/pkg/dart2bytecode/testcases/hello.dart
+  [1] = DirectCall 'dart:core::_checkLoaded', ArgDesc num-args 1, num-type-args 0, names []
+  [2] = Reserved
+  [3] = DirectCall 'DART_SDK/pkg/dart2bytecode/testcases/hello.dart::main', ArgDesc num-args 0, num-type-args 0, names []
+  [4] = Reserved
 }
 
 
@@ -35,13 +36,14 @@ Function 'testLoadLibrary', static, reflectable, debuggable
 Bytecode {
   Entry                0
   CheckStack           0
-  PushNull
-  DirectCall           CP#0, 1
+  PushConstant         CP#0
+  DirectCall           CP#1, 1
   ReturnTOS
 }
 ConstantPool {
-  [0] = DirectCall 'dart:async::Future::value (constructor)', ArgDesc num-args 1, num-type-args 0, names []
-  [1] = Reserved
+  [0] = DeferredLibraryPrefix 'lib', DART_SDK/pkg/dart2bytecode/testcases/deferred_lib.dart -> DART_SDK/pkg/dart2bytecode/testcases/hello.dart
+  [1] = DirectCall 'dart:core::_loadLibrary', ArgDesc num-args 1, num-type-args 0, names []
+  [2] = Reserved
 }
 
 

runtime/vm/bytecode_reader.cc

@@ -523,6 +523,7 @@ intptr_t BytecodeReaderHelper::ReadConstantPool(const Function& function,
     kDynamicCall,
     kExternalCall,
     kFfiCall,
+    kDeferredLibraryPrefix,
   };
 
   Object& obj = Object::Handle(Z);
@@ -700,6 +701,21 @@ intptr_t BytecodeReaderHelper::ReadConstantPool(const Function& function,
         pool.SetRawValueAt(i, 0);
         continue;
       }
+      case ConstantPoolTag::kDeferredLibraryPrefix: {
+        name ^= ReadObject();
+        ASSERT(name.IsSymbol());
+        const auto& enclosing_library = Library::CheckedHandle(Z, ReadObject());
+        const auto& target_library = Library::CheckedHandle(Z, ReadObject());
+        obj = enclosing_library.LookupLocalLibraryPrefix(name);
+        if (obj.IsNull()) {
+          obj = Namespace::New(target_library, Object::null_array(),
+                               Object::null_array(), enclosing_library);
+          obj = LibraryPrefix::New(name, Namespace::Cast(obj),
+                                   /*deferred_load=*/true, enclosing_library);
+          enclosing_library.AddObject(LibraryPrefix::Cast(obj), name);
+        }
+        ASSERT(LibraryPrefix::Cast(obj).GetLibrary(0) == target_library.ptr());
+      } break;
       default:
         UNREACHABLE();
     }