Implement eager instantiation and canonicalization of type arguments at run

runtime/vm/stub_code_arm.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/heap.h"
 #include "vm/instructions.h"
 #include "vm/object_store.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
 DEFINE_FLAG(bool, use_slow_path, false,
     "Set to true for debugging & verifying the slow paths.");
+DECLARE_FLAG(bool, trace_optimized_ic_calls);
 DECLARE_FLAG(int, optimization_counter_threshold);
-DECLARE_FLAG(bool, trace_optimized_ic_calls);
 
 
 // Input parameters:
 //   LR : return address.
 //   SP : address of last argument in argument array.
 //   SP + 4*R4 - 4 : address of first argument in argument array.
 //   SP + 4*R4 : address of return value.
 //   R5 : address of the runtime function to call.
 //   R4 : number of arguments to the call.
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
@@ skipping 1066 matching lines @@
   // The generated code is different if the class is parameterized.
   const bool is_cls_parameterized = cls.NumTypeArguments() > 0;
   ASSERT(!is_cls_parameterized ||
          (cls.type_arguments_field_offset() != Class::kNoTypeArguments));
   // kInlineInstanceSize is a constant used as a threshold for determining
   // when the object initialization should be done as a loop or as
   // straight line code.
   const int kInlineInstanceSize = 12;
   const intptr_t instance_size = cls.instance_size();
   ASSERT(instance_size > 0);
-  const intptr_t type_args_size = InstantiatedTypeArguments::InstanceSize();
-  if (FLAG_inline_alloc &&
-      Heap::IsAllocatableInNewSpace(instance_size + type_args_size)) {
-    Label slow_case;
+  Label slow_case_with_type_arguments;
+  if (FLAG_inline_alloc && Heap::IsAllocatableInNewSpace(instance_size)) {
+    Label slow_case_reload_type_arguments;
+    if (is_cls_parameterized) {
+      // Instantiation of the type arguments vector is only required if an
+      // instantiator is provided (not kNoInstantiator, but may be null).
+      __ ldm(IA, SP, (1 << R0) | (1 << R1));
+      // R1: type arguments, instantiated or not.
+      // R0: instantiator type arguments or kNoInstantiator.
+      Label type_arguments_ready;
+      __ CompareImmediate(R0, Smi::RawValue(StubCode::kNoInstantiator));
+      __ b(&type_arguments_ready, EQ);
+      // Lookup instantiator R0 in instantiations array of type arguments R1
+      // and, if found, use cached instantiated type arguments.
+      __ ldr(R2, FieldAddress(R1, TypeArguments::instantiations_offset()));
+      __ ldr(R3, FieldAddress(R2, Array::length_offset()));
+      __ AddImmediate(R2, Array::data_offset() - kHeapObjectTag);
+      __ add(R3, R2, ShifterOperand(R3, LSL, 1));  // R3 is Smi.
+      Label loop, found;
+      __ Bind(&loop);
+      __ cmp(R2, ShifterOperand(R3));
+      __ b(&slow_case_reload_type_arguments, CS);  // Unsigned higher or equal.
+      __ ldr(R1, Address(R2, 0 * kWordSize));  // Cached instantiator.
+      __ cmp(R1, ShifterOperand(R0));
+      __ b(&found, EQ);
+      __ CompareImmediate(R1, Smi::RawValue(StubCode::kNoInstantiator));
+      __ b(&slow_case_reload_type_arguments, EQ);
+      __ AddImmediate(R2, 2 * kWordSize);
+      __ b(&loop);
+      __ Bind(&found);
+      __ ldr(R1, Address(R2, 1 * kWordSize));  // Cached instantiated args.
+      __ LoadImmediate(R0, Smi::RawValue(StubCode::kNoInstantiator));
+      __ Bind(&type_arguments_ready);
+      // R1: instantiated type arguments.
+      // R0: kNoInstantiator.
+    }
+    // Allocate the object and update top to point to
+    // next object start and initialize the allocated object.
+    // R1: instantiated type arguments (if is_cls_parameterized).
+    // R0: kNoInstantiator (if is_cls_parameterized).
     Heap* heap = Isolate::Current()->heap();
     __ LoadImmediate(R5, heap->TopAddress());
     __ ldr(R2, Address(R5, 0));
     __ AddImmediate(R3, R2, instance_size);
-    if (is_cls_parameterized) {
-      __ ldm(IA, SP, (1 << R0) | (1 << R1));
-      __ mov(R4, ShifterOperand(R3));
-      // A new InstantiatedTypeArguments object only needs to be allocated if
-      // the instantiator is provided (not kNoInstantiator, but may be null).
-      __ CompareImmediate(R0, Smi::RawValue(StubCode::kNoInstantiator));
-      __ AddImmediate(R3, type_args_size, NE);
-      // R4: potential new object end and, if R4 != R3, potential new
-      // InstantiatedTypeArguments object start.
-    }
     // Check if the allocation fits into the remaining space.
     // R2: potential new object start.
     // R3: potential next object start.
     __ LoadImmediate(IP, heap->EndAddress());
     __ ldr(IP, Address(IP, 0));
     __ cmp(R3, ShifterOperand(IP));
     if (FLAG_use_slow_path) {
-      __ b(&slow_case);
+      __ b(&slow_case_with_type_arguments);
     } else {
-      __ b(&slow_case, CS);  // Branch if unsigned higher or equal.
+      __ b(&slow_case_with_type_arguments, CS);  // Unsigned higher or equal.
     }
-
-    // Successfully allocated the object(s), now update top to point to
-    // next object start and initialize the object.
     __ str(R3, Address(R5, 0));
     __ UpdateAllocationStats(cls.id(), R5);
 
-    if (is_cls_parameterized) {
-      // Initialize the type arguments field in the object.
-      // R2: new object start.
-      // R4: potential new object end and, if R4 != R3, potential new
-      // InstantiatedTypeArguments object start.
-      // R3: next object start.
-      Label type_arguments_ready;
-      __ cmp(R4, ShifterOperand(R3));
-      __ b(&type_arguments_ready, EQ);
-      // Initialize InstantiatedTypeArguments object at R4.
-      __ str(R1, Address(R4,
-          InstantiatedTypeArguments::uninstantiated_type_arguments_offset()));
-      __ str(R0, Address(R4,
-          InstantiatedTypeArguments::instantiator_type_arguments_offset()));
-      const Class& ita_cls =
-          Class::ZoneHandle(Object::instantiated_type_arguments_class());
-      // Set the tags.
-      uword tags = 0;
-      tags = RawObject::SizeTag::update(type_args_size, tags);
-      tags = RawObject::ClassIdTag::update(ita_cls.id(), tags);
-      __ LoadImmediate(R0, tags);
-      __ str(R0, Address(R4, Instance::tags_offset()));
-      // Set the new InstantiatedTypeArguments object (R4) as the type
-      // arguments (R1) of the new object (R2).
-      __ add(R1, R4, ShifterOperand(kHeapObjectTag));
-      // Set R3 to new object end.
-      __ mov(R3, ShifterOperand(R4));
-      __ Bind(&type_arguments_ready);
-      // R2: new object.
-      // R1: new object type arguments.
-    }
-
     // R2: new object start.
     // R3: next object start.
     // R1: new object type arguments (if is_cls_parameterized).
     // Set the tags.
     uword tags = 0;
     tags = RawObject::SizeTag::update(instance_size, tags);
     ASSERT(cls.id() != kIllegalCid);
     tags = RawObject::ClassIdTag::update(cls.id(), tags);
     __ LoadImmediate(R0, tags);
     __ str(R0, Address(R2, Instance::tags_offset()));
@@ skipping 36 matching lines @@
       // R1: new object type arguments.
       // Set the type arguments in the new object.
       __ StoreToOffset(kWord, R1, R2, cls.type_arguments_field_offset());
     }
     // Done allocating and initializing the instance.
     // R2: new object still missing its heap tag.
     __ add(R0, R2, ShifterOperand(kHeapObjectTag));
     // R0: new object.
     __ Ret();
 
-    __ Bind(&slow_case);
+    __ Bind(&slow_case_reload_type_arguments);
   }
   if (is_cls_parameterized) {
     __ ldm(IA, SP, (1 << R0) | (1 << R1));
   }
+  __ Bind(&slow_case_with_type_arguments);
+  // If is_cls_parameterized:
+  // R1: new object type arguments (instantiated or not).
+  // R0: instantiator type arguments or kNoInstantiator.
   // Create a stub frame as we are pushing some objects on the stack before
   // calling into the runtime.
   __ EnterStubFrame(true);  // Uses pool pointer to pass cls to runtime.
   __ LoadImmediate(R2, reinterpret_cast<intptr_t>(Object::null()));
   __ Push(R2);  // Setup space on stack for return value.
   __ PushObject(cls);  // Push class of object to be allocated.
   if (is_cls_parameterized) {
     // Push type arguments of object to be allocated and of instantiator.
     __ PushList((1 << R0) | (1 << R1));
   } else {
@@ skipping 622 matching lines @@
 // R1: instantiator type arguments or NULL.
 // R2: cache array.
 // Result in R1: null -> not found, otherwise result (true or false).
 static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
   ASSERT((1 <= n) && (n <= 3));
   if (n > 1) {
     // Get instance type arguments.
     __ LoadClass(R3, R0, R4);
     // Compute instance type arguments into R4.
     Label has_no_type_arguments;
+    __ LoadImmediate(R4, reinterpret_cast<intptr_t>(Object::null()));
     __ ldr(R5, FieldAddress(R3,
         Class::type_arguments_field_offset_in_words_offset()));
     __ CompareImmediate(R5, Class::kNoTypeArguments);
     __ b(&has_no_type_arguments, EQ);
     __ add(R5, R0, ShifterOperand(R5, LSL, 2));
     __ ldr(R4, FieldAddress(R5, 0));
     __ Bind(&has_no_type_arguments);
   }
   __ LoadClassId(R3, R0);
   // R0: instance.
@@ skipping 241 matching lines @@
   const Register right = R0;
   __ ldr(left, Address(SP, 1 * kWordSize));
   __ ldr(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM