Trace allocation of arrays

runtime/vm/stub_code_arm64.cc

 // Copyright (c) 2014, 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_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 643 matching lines @@
 // Input parameters:
 //   LR: return address.
 //   R2: array length as Smi.
 //   R1: array element type (either NULL or an instantiated type).
 // NOTE: R2 cannot be clobbered here as the caller relies on it being saved.
 // The newly allocated object is returned in R0.
 void StubCode::GeneratePatchableAllocateArrayStub(Assembler* assembler,
     uword* entry_patch_offset, uword* patch_code_pc_offset) {
   *entry_patch_offset = assembler->CodeSize();
   Label slow_case;
+  Isolate* isolate = Isolate::Current();
+  const Class& cls = Class::Handle(isolate->object_store()->array_class());
+  ASSERT(!cls.IsNull());
   // Compute the size to be allocated, it is based on the array length
   // and is computed as:
   // RoundedAllocationSize((array_length * kwordSize) + sizeof(RawArray)).
   // Assert that length is a Smi.
   __ tsti(R2, Immediate(kSmiTagMask));
-  if (FLAG_use_slow_path) {
+  if (FLAG_use_slow_path || cls.trace_allocation()) {
     __ b(&slow_case);
   } else {
     __ b(&slow_case, NE);
   }
   __ cmp(R2, Operand(0));
   __ b(&slow_case, LT);
 
-  Isolate* isolate = Isolate::Current();
   Heap* heap = isolate->heap();
   const intptr_t cid = kArrayCid;
   Heap::Space space = heap->SpaceForAllocation(cid);
   const uword top_address = heap->TopAddress(space);
   __ LoadImmediate(R8, top_address, kNoPP);
   const uword end_address = heap->EndAddress(space);
   ASSERT(top_address < end_address);
   const uword top_offset = 0;
   const uword end_offset = end_address - top_address;
 
@@ skipping 1499 matching lines @@
 // Result:
 //  R1: entry point.
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler, R0, R1, R1);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64