Patchable AllocateArray stub, like instance allocation stubs.

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 417 matching lines @@
   __ Pop(R0);
   // Remove the stub frame.
   __ LeaveStubFrame();
   // Jump to the dart function.
   __ LoadFieldFromOffset(R0, R0, Code::instructions_offset(), kNoPP);
   __ AddImmediate(R0, R0, Instructions::HeaderSize() - kHeapObjectTag, kNoPP);
   __ br(R0);
 }
 
 
+// Called from array allocate instruction when the allocation stub has been
+// disabled.
+// R1: element type (preserved).
+// R2: length (preserved).
+void StubCode::GenerateFixAllocateArrayStubTargetStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  // Setup space on stack for return value and preserve length, element type.
+  __ Push(R1);
+  __ Push(R2);
+  __ PushObject(Object::null_object(), PP);
+  __ CallRuntime(kFixAllocationStubTargetRuntimeEntry, 0);
+  // Get Code object result and restore length, element type.
+  __ Pop(R0);
+  __ Pop(R2);
+  __ Pop(R1);
+  // Remove the stub frame.
+  __ LeaveStubFrame();
+  // Jump to the dart function.
+  __ LoadFieldFromOffset(R0, R0, Code::instructions_offset(), kNoPP);
+  __ AddImmediate(R0, R0, Instructions::HeaderSize() - kHeapObjectTag, kNoPP);
+  __ br(R0);
+}
+
+
 // Input parameters:
 //   R2: smi-tagged argument count, may be zero.
 //   FP[kParamEndSlotFromFp + 1]: last argument.
 static void PushArgumentsArray(Assembler* assembler) {
   StubCode* stub_code = Isolate::Current()->stub_code();
   // Allocate array to store arguments of caller.
   __ LoadObject(R1, Object::null_object(), PP);
   // R1: null element type for raw Array.
   // R2: smi-tagged argument count, may be zero.
-  __ BranchLink(&stub_code->AllocateArrayLabel(), PP);
+  const Code& array_stub = Code::Handle(stub_code->GetAllocateArrayStub());
+  const ExternalLabel array_label(array_stub.EntryPoint());
+  __ BranchLink(&array_label, PP);
   // R0: newly allocated array.
   // R2: smi-tagged argument count, may be zero (was preserved by the stub).
   __ Push(R0);  // Array is in R0 and on top of stack.
   __ add(R1, FP, Operand(R2, LSL, 2));
   __ AddImmediate(R1, R1, kParamEndSlotFromFp * kWordSize, PP);
   __ AddImmediate(R3, R0, Array::data_offset() - kHeapObjectTag, PP);
   // R1: address of first argument on stack.
   // R3: address of first argument in array.
 
   Label loop, loop_exit;
@@ skipping 177 matching lines @@
 }
 
 
 // Called for inline allocation of arrays.
 // 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::GenerateAllocateArrayStub(Assembler* assembler) {
+void StubCode::GeneratePatchableAllocateArrayStub(Assembler* assembler,
+    uword* entry_patch_offset, uword* patch_code_pc_offset) {
+  *entry_patch_offset = assembler->CodeSize();
   Label slow_case;
   // 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, kSmiTagMask);
   if (FLAG_use_slow_path) {
     __ b(&slow_case);
   } else {
     __ b(&slow_case, NE);
@@ skipping 111 matching lines @@
   __ PushObject(Object::null_object(), PP);
   __ Push(R2);
   __ Push(R1);
   __ CallRuntime(kAllocateArrayRuntimeEntry, 2);
   // Pop arguments; result is popped in IP.
   __ Pop(R1);
   __ Pop(R2);
   __ Pop(R0);
   __ LeaveStubFrame();
   __ ret();
+  *patch_code_pc_offset = assembler->CodeSize();
+  StubCode* stub_code = Isolate::Current()->stub_code();
+  __ BranchPatchable(&stub_code->FixAllocateArrayStubTargetLabel());
 }
 
 
 // Called when invoking Dart code from C++ (VM code).
 // Input parameters:
 //   LR : points to return address.
 //   R0 : entrypoint of the Dart function to call.
 //   R1 : arguments descriptor array.
 //   R2 : arguments array.
 //   R3 : new context containing the current isolate pointer.
@@ skipping 1306 matching lines @@
   const Register right = R0;
   __ LoadFromOffset(left, SP, 1 * kWordSize, kNoPP);
   __ LoadFromOffset(right, SP, 0 * kWordSize, kNoPP);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64