Array constructor expects AllocationSite or undefined as feedback.

src/arm/code-stubs-arm.cc

 // Copyright 2012 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 3014 matching lines @@
     // Check that the function is really a JavaScript function.
     // r1: pushed function (to be verified)
     __ JumpIfSmi(r1, &non_function);
 
     // Goto slow case if we do not have a function.
     __ CompareObjectType(r1, r4, r4, JS_FUNCTION_TYPE);
     __ b(ne, &slow);
 
     if (RecordCallTarget()) {
       GenerateRecordCallTarget(masm);
+      // Type information was updated. Because we may call Array, which
+      // expects either undefined or an AllocationSite in ebx we need
+      // to set ebx to undefined.
+      __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
     }
   }
 
   // Fast-case: Invoke the function now.
   // r1: pushed function
   ParameterCount actual(argc_);
 
   if (CallAsMethod()) {
     if (NeedsChecks()) {
       // Do not transform the receiver for strict mode functions.
@@ skipping 82 matching lines @@
   //      vector (Smi)
   Label slow, non_function_call;
 
   // Check that the function is not a smi.
   __ JumpIfSmi(r1, &non_function_call);
   // Check that the function is a JSFunction.
   __ CompareObjectType(r1, r4, r4, JS_FUNCTION_TYPE);
   __ b(ne, &slow);
 
   if (RecordCallTarget()) {
+    Label feedback_register_initialized;
     GenerateRecordCallTarget(masm);
+
+    // Put the AllocationSite from the feedback vector into r2, or undefined.
+    __ add(r5, r2, Operand::PointerOffsetFromSmiKey(r3));
+    __ ldr(r2, FieldMemOperand(r5, FixedArray::kHeaderSize));
+    __ ldr(r5, FieldMemOperand(r2, AllocationSite::kMapOffset));
+    __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);
+    __ b(eq, &feedback_register_initialized);
+    __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
+    __ bind(&feedback_register_initialized);
+    __ AssertUndefinedOrAllocationSite(r2, r5);
   }
 
   // Jump to the function-specific construct stub.
   Register jmp_reg = r4;
   __ ldr(jmp_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
   __ ldr(jmp_reg, FieldMemOperand(jmp_reg,
                                   SharedFunctionInfo::kConstructStubOffset));
   __ add(pc, jmp_reg, Operand(Code::kHeaderSize - kHeapObjectTag));
 
   // r0: number of arguments
@@ skipping 2054 matching lines @@
   } else {
     UNREACHABLE();
   }
 }
 
 
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- r0 : argc (only if argument_count_ == ANY)
   //  -- r1 : constructor
-  //  -- r2 : feedback vector (fixed array or megamorphic symbol)
-  //  -- r3 : slot index (if r2 is fixed array)
+  //  -- r2 : AllocationSite or undefined
   //  -- sp[0] : return address
   //  -- sp[4] : last argument
   // -----------------------------------
 
-  ASSERT_EQ(*TypeFeedbackInfo::MegamorphicSentinel(masm->isolate()),
-            masm->isolate()->heap()->megamorphic_symbol());
-
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
     // Initial map for the builtin Array function should be a map.
     __ ldr(r4, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
     // Will both indicate a NULL and a Smi.
     __ tst(r4, Operand(kSmiTagMask));
     __ Assert(ne, kUnexpectedInitialMapForArrayFunction);
     __ CompareObjectType(r4, r4, r5, MAP_TYPE);
     __ Assert(eq, kUnexpectedInitialMapForArrayFunction);
 
-    // We should either have the megamorphic symbol in ebx or a valid
-    // fixed array.
-    Label okay_here;
-    Handle<Map> fixed_array_map = masm->isolate()->factory()->fixed_array_map();
-    __ CompareRoot(r2, Heap::kMegamorphicSymbolRootIndex);
-    __ b(eq, &okay_here);
-    __ ldr(r4, FieldMemOperand(r2, 0));
-    __ cmp(r4, Operand(fixed_array_map));
-    __ Assert(eq, kExpectedFixedArrayInRegisterR2);
-
-    // r3 should be a smi if we don't have undefined in r2
-    __ AssertSmi(r3);
-
-    __ bind(&okay_here);
+    // We should either have undefined in r2 or a valid AllocationSite
+    __ AssertUndefinedOrAllocationSite(r2, r4);
   }
 
   Label no_info;
   // Get the elements kind and case on that.
-  __ CompareRoot(r2, Heap::kMegamorphicSymbolRootIndex);
+  __ CompareRoot(r2, Heap::kUndefinedValueRootIndex);
   __ b(eq, &no_info);
-  __ add(r2, r2, Operand::PointerOffsetFromSmiKey(r3));
-  __ ldr(r2, FieldMemOperand(r2, FixedArray::kHeaderSize));
-
-  // If the feedback vector is undefined, or contains anything other than an
-  // AllocationSite, call an array constructor that doesn't use AllocationSites.
-  __ ldr(r4, FieldMemOperand(r2, 0));
-  __ CompareRoot(r4, Heap::kAllocationSiteMapRootIndex);
-  __ b(ne, &no_info);
 
   __ ldr(r3, FieldMemOperand(r2, AllocationSite::kTransitionInfoOffset));
   __ SmiUntag(r3);
   STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
   __ and_(r3, r3, Operand(AllocationSite::ElementsKindBits::kMask));
   GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
 }
@@ skipping 226 matching lines @@
                               MemOperand(fp, 6 * kPointerSize),
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM