Deletion barrier: Distinguish+verify field initialization in ia32 generated code.

runtime/vm/stub_code_ia32.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_IA32)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 351 matching lines @@
   __ pushl(EAX);  // Array is in EAX and on top of stack.
   __ leal(EBX, Address(EBP, EDX, TIMES_4, kParamEndSlotFromFp * kWordSize));
   __ leal(ECX, FieldAddress(EAX, Array::data_offset()));
   // EBX: address of first argument on stack.
   // ECX: address of first argument in array.
   Label loop, loop_condition;
   __ jmp(&loop_condition, Assembler::kNearJump);
   __ Bind(&loop);
   __ movl(EDI, Address(EBX, 0));
   // No generational barrier needed, since array is in new space.
-  __ StoreIntoObjectNoBarrier(EAX, Address(ECX, 0), EDI);
+  __ InitializeFieldNoBarrier(EAX, Address(ECX, 0), EDI);
   __ AddImmediate(ECX, Immediate(kWordSize));
   __ AddImmediate(EBX, Immediate(-kWordSize));
   __ Bind(&loop_condition);
   __ decl(EDX);
   __ j(POSITIVE, &loop, Assembler::kNearJump);
 }
 
 
 DECLARE_LEAF_RUNTIME_ENTRY(intptr_t, DeoptimizeCopyFrame,
                            intptr_t deopt_reason,
@@ skipping 241 matching lines @@
 
     // Get the class index and insert it into the tags.
     __ orl(EDI, Immediate(RawObject::ClassIdTag::encode(cid)));
     __ movl(FieldAddress(EAX, Array::tags_offset()), EDI);  // Tags.
   }
   // EAX: new object start as a tagged pointer.
   // EBX: new object end address.
   // ECX: array element type.
   // EDX: Array length as Smi (preserved).
   // Store the type argument field.
-  __ StoreIntoObjectNoBarrier(EAX,
+  __ InitializeFieldNoBarrier(EAX,
                               FieldAddress(EAX, Array::type_arguments_offset()),
                               ECX);
 
   // Set the length field.
-  __ StoreIntoObjectNoBarrier(EAX,
+  __ InitializeFieldNoBarrier(EAX,
                               FieldAddress(EAX, Array::length_offset()),
                               EDX);
 
   // Initialize all array elements to raw_null.
   // EAX: new object start as a tagged pointer.
   // EBX: new object end address.
   // EDI: iterator which initially points to the start of the variable
   // data area to be initialized.
   // ECX: array element type.
   // EDX: array length as Smi.
   __ leal(EDI, FieldAddress(EAX, sizeof(RawArray)));
   Label done;
   Label init_loop;
   __ Bind(&init_loop);
   __ cmpl(EDI, EBX);
   __ j(ABOVE_EQUAL, &done, Assembler::kNearJump);
   // No generational barrier needed, since we are storing null.
-  __ StoreIntoObjectNoBarrier(EAX, Address(EDI, 0), Object::null_object());
+  __ InitializeFieldNoBarrier(EAX, Address(EDI, 0), Object::null_object());
   __ addl(EDI, Immediate(kWordSize));
   __ jmp(&init_loop, Assembler::kNearJump);
   __ Bind(&done);
   __ ret();  // returns the newly allocated object in EAX.
 
   // Unable to allocate the array using the fast inline code, just call
   // into the runtime.
   __ Bind(&slow_case);
   // Create a stub frame as we are pushing some objects on the stack before
   // calling into the runtime.
@@ skipping 138 matching lines @@
     __ movl(EAX, Address::Absolute(heap->TopAddress(space)));
     __ addl(EBX, EAX);
     // Check if the allocation fits into the remaining space.
     // EAX: potential new object.
     // EBX: potential next object start.
     // EDX: number of context variables.
     __ cmpl(EBX, Address::Absolute(heap->EndAddress(space)));
     if (FLAG_use_slow_path) {
       __ jmp(&slow_case);
     } else {
-      __ j(ABOVE_EQUAL, &slow_case, Assembler::kNearJump);
+#if defined(DEBUG)
+      static const bool kJumpLength = Assembler::kFarJump;
+#else
+      static const bool kJumpLength = Assembler::kNearJump;
+#endif  // DEBUG
+      __ j(ABOVE_EQUAL, &slow_case, kJumpLength);
     }
 
     // Successfully allocated the object, now update top to point to
     // next object start and initialize the object.
     // EAX: new object.
     // EBX: next object start.
     // EDX: number of context variables.
     __ movl(Address::Absolute(heap->TopAddress(space)), EBX);
     __ addl(EAX, Immediate(kHeapObjectTag));
     // EBX: Size of allocation in bytes.
@@ skipping 27 matching lines @@
 
     // Setup up number of context variables field.
     // EAX: new object.
     // EDX: number of context variables as integer value (not object).
     __ movl(FieldAddress(EAX, Context::num_variables_offset()), EDX);
 
     // Setup the parent field.
     // EAX: new object.
     // EDX: number of context variables.
     // No generational barrier needed, since we are storing null.
-    __ StoreIntoObjectNoBarrier(EAX,
+    __ InitializeFieldNoBarrier(EAX,
                                 FieldAddress(EAX, Context::parent_offset()),
                                 Object::null_object());
 
     // Initialize the context variables.
     // EAX: new object.
     // EDX: number of context variables.
     {
       Label loop, entry;
       __ leal(EBX, FieldAddress(EAX, Context::variable_offset(0)));
 
       __ jmp(&entry, Assembler::kNearJump);
       __ Bind(&loop);
       __ decl(EDX);
       // No generational barrier needed, since we are storing null.
-      __ StoreIntoObjectNoBarrier(EAX,
+      __ InitializeFieldNoBarrier(EAX,
                                   Address(EBX, EDX, TIMES_4, 0),
                                   Object::null_object());
       __ Bind(&entry);
       __ cmpl(EDX, Immediate(0));
       __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
     }
 
     // Done allocating and initializing the context.
     // EAX: new object.
     __ ret();
@@ skipping 157 matching lines @@
     // EAX: new object (tagged).
     // EBX: next object start.
     // EDX: new object type arguments (if is_cls_parameterized).
     // First try inlining the initialization without a loop.
     if (instance_size < (kInlineInstanceSize * kWordSize)) {
       // Check if the object contains any non-header fields.
       // Small objects are initialized using a consecutive set of writes.
       for (intptr_t current_offset = Instance::NextFieldOffset();
            current_offset < instance_size;
            current_offset += kWordSize) {
-        __ StoreIntoObjectNoBarrier(EAX,
+        __ InitializeFieldNoBarrier(EAX,
                                     FieldAddress(EAX, current_offset),
                                     Object::null_object());
       }
     } else {
       __ leal(ECX, FieldAddress(EAX, Instance::NextFieldOffset()));
       // Loop until the whole object is initialized.
       // EAX: new object (tagged).
       // EBX: next object start.
       // ECX: next word to be initialized.
       // EDX: new object type arguments (if is_cls_parameterized).
       Label init_loop;
       Label done;
       __ Bind(&init_loop);
       __ cmpl(ECX, EBX);
       __ j(ABOVE_EQUAL, &done, Assembler::kNearJump);
-      __ StoreIntoObjectNoBarrier(EAX,
+      __ InitializeFieldNoBarrier(EAX,
                                   Address(ECX, 0),
                                   Object::null_object());
       __ addl(ECX, Immediate(kWordSize));
       __ jmp(&init_loop, Assembler::kNearJump);
       __ Bind(&done);
     }
     if (is_cls_parameterized) {
       // EDX: new object type arguments.
       // Set the type arguments in the new object.
       intptr_t offset = cls.type_arguments_field_offset();
-      __ StoreIntoObjectNoBarrier(EAX, FieldAddress(EAX, offset), EDX);
+      // TODO(koda): Figure out why previous content is sometimes null here.
+      __ InitializeFieldNoBarrier(EAX, FieldAddress(EAX, offset), EDX);
     }
     // Done allocating and initializing the instance.
     // EAX: new object (tagged).
     __ ret();
 
     __ Bind(&slow_case);
   }
   // If is_cls_parameterized:
   // EDX: new object type arguments.
   // Create a stub frame as we are pushing some objects on the stack before
@@ skipping 944 matching lines @@
   const Register temp = ECX;
   __ movl(left, Address(ESP, 2 * kWordSize));
   __ movl(right, Address(ESP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32