Pretenure call new support.

src/a64/builtins-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 311 matching lines @@
   CallRuntimePassFunction(masm, Runtime::kTryInstallOptimizedCode);
   GenerateTailCallToReturnedCode(masm);
 
   __ Bind(&ok);
   GenerateTailCallToSharedCode(masm);
 }
 
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
-                                           bool count_constructions) {
+                                           bool count_constructions,
+                                           bool create_memento) {
   // ----------- S t a t e -------------
   //  -- x0     : number of arguments
   //  -- x1     : constructor function
+  //  -- x2     : allocation site or undefined
   //  -- lr     : return address
   //  -- sp[...]: constructor arguments
   // -----------------------------------
 
   ASM_LOCATION("Builtins::Generate_JSConstructStubHelper");
   // Should never count constructions for api objects.
   ASSERT(!is_api_function || !count_constructions);
+  // Should never create mementos for api functions.
+  ASSERT(!is_api_function || !create_memento);
+  // Should never create mementos before slack tracking is finished.
+  ASSERT(!count_constructions || !create_memento);
 
   Isolate* isolate = masm->isolate();
 
   // Enter a construct frame.
   {
     FrameScope scope(masm, StackFrame::CONSTRUCT);
 
-    // Preserve the two incoming parameters on the stack.
+    // Preserve the three incoming parameters on the stack.
+    if (create_memento) {
+      __ AssertUndefinedOrAllocationSite(x2, x10);
+      __ Push(x2);
+    }
+
     Register argc = x0;
     Register constructor = x1;
     // x1: constructor function
     __ SmiTag(argc);
     __ Push(argc, constructor);
     // sp[0] : Constructor function.
     // sp[1]: number of arguments (smi-tagged)
 
     // Try to allocate the object without transitioning into C code. If any of
     // the preconditions is not met, the code bails out to the runtime call.
@@ skipping 39 matching lines @@
         // The call will replace the stub, so the countdown is only done once.
         __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);
         __ Pop(init_map, constructor);
         __ Bind(&allocate);
       }
 
       // Now allocate the JSObject on the heap.
       Register obj_size = x3;
       Register new_obj = x4;
       __ Ldrb(obj_size, FieldMemOperand(init_map, Map::kInstanceSizeOffset));
-      __ Allocate(obj_size, new_obj, x10, x11, &rt_call, SIZE_IN_WORDS);
+      if (create_memento) {
+        __ Add(x7, obj_size,
+               Operand(AllocationMemento::kSize / kPointerSize));
+        __ Allocate(x7, new_obj, x10, x11, &rt_call, SIZE_IN_WORDS);
+      } else {
+        __ Allocate(obj_size, new_obj, x10, x11, &rt_call, SIZE_IN_WORDS);
+      }
 
       // Allocated the JSObject, now initialize the fields. Map is set to
       // initial map and properties and elements are set to empty fixed array.
       // NB. the object pointer is not tagged, so MemOperand is used.
       Register empty = x5;
       __ LoadRoot(empty, Heap::kEmptyFixedArrayRootIndex);
       __ Str(init_map, MemOperand(new_obj, JSObject::kMapOffset));
       __ Str(empty, MemOperand(new_obj, JSObject::kPropertiesOffset));
       __ Str(empty, MemOperand(new_obj, JSObject::kElementsOffset));
 
@@ skipping 30 matching lines @@
           __ Assert(le, kUnexpectedNumberOfPreAllocatedPropertyFields);
         }
         __ InitializeFieldsWithFiller(first_prop, first_non_prealloc, undef);
         // To allow for truncation.
         __ LoadRoot(x12, Heap::kOnePointerFillerMapRootIndex);
         __ InitializeFieldsWithFiller(first_prop, obj_end, x12);
       } else {
         __ InitializeFieldsWithFiller(first_prop, obj_end, undef);
       }
 
+      if (create_memento) {

[mvstanton, 2014/02/19 08:40:26]

Hannes, I've changed this snippet of code to fit the same pattern as the other
three platforms:

if (count_constructions) {
  // object filling code for this case.
} else if (create_memento) {
  // object filling code for this case.
} else {
  // simplest case for filling object fields.
}

There is a line or two of duplication, but I think it's worth having a uniform
logical structure. In some platforms it's "not quite" duplication, like we'll
use register ESI instead of EDI in some operands in order to save an instruction
elsewhere.

+        // It's important that first_prop (x5) contains new space top in order
+        // to satisfy the RESULT_CONTAINS_TOP flag in the Allocate statement
+        // below. Therefore the memento is initialized continuing the
+        // post-increment style of the JSObject fields before.
+        __ LoadRoot(x14, Heap::kAllocationMementoMapRootIndex);
+        ASSERT_EQ(0 * kPointerSize, AllocationMemento::kMapOffset);
+        __ Str(x14, MemOperand(first_prop, kPointerSize, PostIndex));
+        // Load the AllocationSite
+        __ Peek(x14, 2 * kXRegSizeInBytes);
+        ASSERT_EQ(1 * kPointerSize, AllocationMemento::kAllocationSiteOffset);
+        __ Str(x14, MemOperand(first_prop, kPointerSize, PostIndex));
+      }
+
       // Add the object tag to make the JSObject real, so that we can continue
       // and jump into the continuation code at any time from now on. Any
       // failures need to undo the allocation, so that the heap is in a
       // consistent state and verifiable.
       __ Add(new_obj, new_obj, kHeapObjectTag);
 
       // Check if a non-empty properties array is needed. Continue with
       // allocated object if not, or fall through to runtime call if it is.
       Register element_count = x3;
       __ Ldrb(x3, FieldMemOperand(init_map, Map::kUnusedPropertyFieldsOffset));
@@ skipping 39 matching lines @@
 
       // Undo the setting of the new top so that the heap is verifiable. For
       // example, the map's unused properties potentially do not match the
       // allocated objects unused properties.
       __ Bind(&undo_allocation);
       __ UndoAllocationInNewSpace(new_obj, x14);
     }
 
     // Allocate the new receiver object using the runtime call.
     __ Bind(&rt_call);
-    __ Push(constructor);  // Argument for Runtime_NewObject.
-    __ CallRuntime(Runtime::kNewObject, 1);
-    __ Mov(x4, x0);
+    Label count_incremented;
+    if (create_memento) {
+      // Get the cell or allocation site.
+      __ Peek(x4, 2 * kXRegSizeInBytes);
+      __ Push(x4);
+      __ Push(constructor);  // Argument for Runtime_NewObject.
+      __ CallRuntime(Runtime::kNewObjectWithAllocationSite, 2);
+      __ Mov(x4, x0);
+      // If we ended up using the runtime, and we want a memento, then the
+      // runtime call made it for us, and we shouldn't do create count
+      // increment.
+      __ jmp(&count_incremented);
+    } else {
+      __ Push(constructor);  // Argument for Runtime_NewObject.
+      __ CallRuntime(Runtime::kNewObject, 1);
+      __ Mov(x4, x0);
+    }
 
     // Receiver for constructor call allocated.
     // x4: JSObject
     __ Bind(&allocated);
+
+    if (create_memento) {
+      __ Peek(x10, 2 * kXRegSizeInBytes);
+      __ JumpIfRoot(x10, Heap::kUndefinedValueRootIndex, &count_incremented);
+      // r2 is an AllocationSite. We are creating a memento from it, so we
+      // need to increment the memento create count.
+      __ Ldr(x5, FieldMemOperand(x10,
+                                 AllocationSite::kPretenureCreateCountOffset));
+      __ Add(x5, x5, Operand(Smi::FromInt(1)));
+      __ Str(x5, FieldMemOperand(x10,
+                                 AllocationSite::kPretenureCreateCountOffset));
+      __ bind(&count_incremented);

[Hannes Payer (out of office), 2014/02/18 16:24:26]

bind outside if?

+    }
+
     __ Push(x4, x4);
 
     // Reload the number of arguments from the stack.
     // Set it up in x0 for the function call below.
     // jssp[0]: receiver
     // jssp[1]: receiver
     // jssp[2]: constructor function
     // jssp[3]: number of arguments (smi-tagged)
     __ Peek(constructor, 2 * kXRegSizeInBytes);  // Load constructor.
     __ Peek(argc, 3 * kXRegSizeInBytes);  // Load number of arguments.
@@ skipping 86 matching lines @@
   }
 
   __ DropBySMI(x1);
   __ Drop(1);
   __ IncrementCounter(isolate->counters()->constructed_objects(), 1, x1, x2);
   __ Ret();
 }
 
 
 void Builtins::Generate_JSConstructStubCountdown(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, true);
+  Generate_JSConstructStubHelper(masm, false, true, false);
 }
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, false);
+  Generate_JSConstructStubHelper(masm, false, false, true);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, false);
+  Generate_JSConstructStubHelper(masm, true, false, false);
 }
 
 
 // Input:
 //   x0: code entry.
 //   x1: function.
 //   x2: receiver.
 //   x3: argc.
 //   x4: argv.
 // Output:
@@ skipping 818 matching lines @@
   __ Bind(&dont_adapt_arguments);
   __ Jump(x3);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM