LibJS/JIT: Compile the GetGlobal bytecode instruction

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/3974ce2069
Pull-request: https://github.com/SerenityOS/serenity/pull/21619
Reviewed-by: https://github.com/Hendiadyoin1

Userland/Libraries/LibJS/Bytecode/CommonImplementations.cpp

@@ -6,6 +6,9 @@
 
 #include <LibJS/Bytecode/CommonImplementations.h>
 #include <LibJS/Bytecode/Interpreter.h>
+#include <LibJS/Runtime/DeclarativeEnvironment.h>
+#include <LibJS/Runtime/GlobalEnvironment.h>
+#include <LibJS/Runtime/ObjectEnvironment.h>
 
 namespace JS::Bytecode {
 
@@ -86,4 +89,54 @@ ThrowCompletionOr<Value> get_by_value(Bytecode::Interpreter& interpreter, Value
     return TRY(object->internal_get(property_key, base_value));
 }
 
+ThrowCompletionOr<Value> get_global(Bytecode::Interpreter& interpreter, IdentifierTableIndex identifier, u32 cache_index)
+{
+    auto& vm = interpreter.vm();
+    auto& realm = *vm.current_realm();
+
+    auto& cache = interpreter.current_executable().global_variable_caches[cache_index];
+    auto& binding_object = realm.global_environment().object_record().binding_object();
+    auto& declarative_record = realm.global_environment().declarative_record();
+
+    // OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
+    // NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
+    auto& shape = binding_object.shape();
+    if (cache.environment_serial_number == declarative_record.environment_serial_number()
+        && &shape == cache.shape
+        && (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
+        return binding_object.get_direct(cache.property_offset.value());
+    }
+
+    cache.environment_serial_number = declarative_record.environment_serial_number();
+
+    auto const& name = interpreter.current_executable().get_identifier(identifier);
+    if (vm.running_execution_context().script_or_module.has<NonnullGCPtr<Module>>()) {
+        // NOTE: GetGlobal is used to access variables stored in the module environment and global environment.
+        //       The module environment is checked first since it precedes the global environment in the environment chain.
+        auto& module_environment = *vm.running_execution_context().script_or_module.get<NonnullGCPtr<Module>>()->environment();
+        if (TRY(module_environment.has_binding(name))) {
+            // TODO: Cache offset of binding value
+            return TRY(module_environment.get_binding_value(vm, name, vm.in_strict_mode()));
+        }
+    }
+
+    if (TRY(declarative_record.has_binding(name))) {
+        // TODO: Cache offset of binding value
+        return TRY(declarative_record.get_binding_value(vm, name, vm.in_strict_mode()));
+    }
+
+    if (TRY(binding_object.has_property(name))) {
+        CacheablePropertyMetadata cacheable_metadata;
+        auto value = TRY(binding_object.internal_get(name, js_undefined(), &cacheable_metadata));
+        if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
+            cache.shape = shape;
+            cache.property_offset = cacheable_metadata.property_offset.value();
+            cache.unique_shape_serial_number = shape.unique_shape_serial_number();
+        }
+        return value;
+    }
+
+    return vm.throw_completion<ReferenceError>(ErrorType::UnknownIdentifier, name);
+}
+
 }

Userland/Libraries/LibJS/Bytecode/CommonImplementations.h

@@ -14,5 +14,6 @@ namespace JS::Bytecode {
 ThrowCompletionOr<NonnullGCPtr<Object>> base_object_for_get(Bytecode::Interpreter&, Value base_value);
 ThrowCompletionOr<Value> get_by_id(Bytecode::Interpreter&, IdentifierTableIndex, Value base_value, Value this_value, u32 cache_index);
 ThrowCompletionOr<Value> get_by_value(Bytecode::Interpreter&, Value base_value, Value property_key_value);
+ThrowCompletionOr<Value> get_global(Bytecode::Interpreter&, IdentifierTableIndex, u32 cache_index);
 
 }

Userland/Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -892,56 +892,8 @@ ThrowCompletionOr<void> GetCalleeAndThisFromEnvironment::execute_impl(Bytecode::
 
 ThrowCompletionOr<void> GetGlobal::execute_impl(Bytecode::Interpreter& interpreter) const
 {
-    auto& vm = interpreter.vm();
-    auto& realm = *vm.current_realm();
-
-    auto& cache = interpreter.current_executable().global_variable_caches[m_cache_index];
-    auto& binding_object = realm.global_environment().object_record().binding_object();
-    auto& declarative_record = realm.global_environment().declarative_record();
-
-    // OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
-    // NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
-    auto& shape = binding_object.shape();
-    if (cache.environment_serial_number == declarative_record.environment_serial_number()
-        && &shape == cache.shape
-        && (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
-        interpreter.accumulator() = binding_object.get_direct(cache.property_offset.value());
-        return {};
-    }
-
-    cache.environment_serial_number = declarative_record.environment_serial_number();
-
-    auto const& name = interpreter.current_executable().get_identifier(m_identifier);
-    if (vm.running_execution_context().script_or_module.has<NonnullGCPtr<Module>>()) {
-        // NOTE: GetGlobal is used to access variables stored in the module environment and global environment.
-        //       The module environment is checked first since it precedes the global environment in the environment chain.
-        auto& module_environment = *vm.running_execution_context().script_or_module.get<NonnullGCPtr<Module>>()->environment();
-        if (TRY(module_environment.has_binding(name))) {
-            // TODO: Cache offset of binding value
-            interpreter.accumulator() = TRY(module_environment.get_binding_value(vm, name, vm.in_strict_mode()));
-            return {};
-        }
-    }
-
-    if (TRY(declarative_record.has_binding(name))) {
-        // TODO: Cache offset of binding value
-        interpreter.accumulator() = TRY(declarative_record.get_binding_value(vm, name, vm.in_strict_mode()));
-        return {};
-    }
-
-    if (TRY(binding_object.has_property(name))) {
-        CacheablePropertyMetadata cacheable_metadata;
-        interpreter.accumulator() = js_undefined();
-        interpreter.accumulator() = TRY(binding_object.internal_get(name, interpreter.accumulator(), &cacheable_metadata));
-        if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
-            cache.shape = shape;
-            cache.property_offset = cacheable_metadata.property_offset.value();
-            cache.unique_shape_serial_number = shape.unique_shape_serial_number();
-        }
-        return {};
-    }
-
-    return vm.throw_completion<ReferenceError>(ErrorType::UnknownIdentifier, name);
+    interpreter.accumulator() = TRY(get_global(interpreter, m_identifier, m_cache_index));
+    return {};
 }
 
 ThrowCompletionOr<void> GetLocal::execute_impl(Bytecode::Interpreter&) const

Userland/Libraries/LibJS/Bytecode/Op.h

@@ -508,6 +508,9 @@ public:
     ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
     DeprecatedString to_deprecated_string_impl(Bytecode::Executable const&) const;
 
+    IdentifierTableIndex identifier() const { return m_identifier; }
+    u32 cache_index() const { return m_cache_index; }
+
 private:
     IdentifierTableIndex m_identifier;
     u32 m_cache_index { 0 };

Userland/Libraries/LibJS/JIT/Compiler.cpp

@@ -416,6 +416,24 @@ void Compiler::compile_get_by_value(Bytecode::Op::GetByValue const& op)
     check_exception();
 }
 
+static Value cxx_get_global(VM& vm, Bytecode::IdentifierTableIndex identifier, u32 cache_index)
+{
+    return TRY_OR_SET_EXCEPTION(Bytecode::get_global(vm.bytecode_interpreter(), identifier, cache_index));
+}
+
+void Compiler::compile_get_global(Bytecode::Op::GetGlobal const& op)
+{
+    m_assembler.mov(
+        Assembler::Operand::Register(ARG1),
+        Assembler::Operand::Imm64(op.identifier().value()));
+    m_assembler.mov(
+        Assembler::Operand::Register(ARG2),
+        Assembler::Operand::Imm64(op.cache_index()));
+    m_assembler.native_call((void*)cxx_get_global);
+    store_vm_register(Bytecode::Register::accumulator(), RET);
+    check_exception();
+}
+
 static Value cxx_to_numeric(VM& vm, Value value)
 {
     return TRY_OR_SET_EXCEPTION(value.to_numeric(vm));
@@ -514,6 +532,9 @@ OwnPtr<NativeExecutable> Compiler::compile(Bytecode::Executable& bytecode_execut
             case Bytecode::Instruction::Type::GetByValue:
                 compiler.compile_get_by_value(static_cast<Bytecode::Op::GetByValue const&>(op));
                 break;
+            case Bytecode::Instruction::Type::GetGlobal:
+                compiler.compile_get_global(static_cast<Bytecode::Op::GetGlobal const&>(op));
+                break;
             case Bytecode::Instruction::Type::ToNumeric:
                 compiler.compile_to_numeric(static_cast<Bytecode::Op::ToNumeric const&>(op));
                 break;

Userland/Libraries/LibJS/JIT/Compiler.h

@@ -55,6 +55,7 @@ private:
     void compile_new_string(Bytecode::Op::NewString const&);
     void compile_get_by_id(Bytecode::Op::GetById const&);
     void compile_get_by_value(Bytecode::Op::GetByValue const&);
+    void compile_get_global(Bytecode::Op::GetGlobal const&);
 
     void store_vm_register(Bytecode::Register, Assembler::Reg);
     void load_vm_register(Assembler::Reg, Bytecode::Register);