Remove fixed contant pool entries by caching some global constants in Thread

runtime/vm/assembler_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"  // NOLINT
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 13 matching lines @@
 DEFINE_FLAG(bool, print_stop_message, false, "Print stop message.");
 DECLARE_FLAG(bool, inline_alloc);
 
 
 Assembler::Assembler(bool use_far_branches)
     : buffer_(),
       prologue_offset_(-1),
       use_far_branches_(use_far_branches),
       comments_(),
       allow_constant_pool_(true) {
-  if (Isolate::Current() != Dart::vm_isolate()) {
-    // These objects and labels need to be accessible through every pool-pointer
-    // at the same index.
-    intptr_t index =
-        object_pool_wrapper_.AddObject(Object::null_object());
-    ASSERT(index == 0);
-
-    index = object_pool_wrapper_.AddObject(Bool::True());
-    ASSERT(index == 1);
-
-    index = object_pool_wrapper_.AddObject(Bool::False());
-    ASSERT(index == 2);
-
-    const Smi& vacant = Smi::Handle(Smi::New(0xfa >> kSmiTagShift));
-    StubCode* stub_code = Isolate::Current()->stub_code();
-    if (stub_code->UpdateStoreBuffer_entry() != NULL) {
-      object_pool_wrapper_.AddExternalLabel(
-          &stub_code->UpdateStoreBufferLabel(), kNotPatchable);
-    } else {
-      object_pool_wrapper_.AddObject(vacant);
-    }
-  }
 }
 
 
 void Assembler::InitializeMemoryWithBreakpoints(uword data, intptr_t length) {
   ASSERT(Utils::IsAligned(data, 4));
   ASSERT(Utils::IsAligned(length, 4));
   const uword end = data + length;
   while (data < end) {
     *reinterpret_cast<int32_t*>(data) = Instr::kBreakPointInstruction;
     data += 4;
@@ skipping 314 matching lines @@
   ldr(dst, Address(dst, lower12));
 }
 
 
 intptr_t Assembler::FindImmediate(int64_t imm) {
   ASSERT(Isolate::Current() != Dart::vm_isolate());
   return object_pool_wrapper_.FindImmediate(imm);
 }
 
 
-// A set of VM objects that are present in every constant pool.
-static bool IsAlwaysInConstantPool(const Object& object) {
-  // TODO(zra): Evaluate putting all VM heap objects into the pool.
-  return (object.raw() == Object::null())
-      || (object.raw() == Bool::True().raw())
-      || (object.raw() == Bool::False().raw());
-}
-
-
-bool Assembler::CanLoadObjectFromPool(const Object& object) {
+bool Assembler::CanLoadFromObjectPool(const Object& object) const {
+  ASSERT(!Thread::CanLoadFromThread(object));
   if (!allow_constant_pool()) {
-    return IsAlwaysInConstantPool(object);
+    return false;
   }
 
   // TODO(zra, kmillikin): Also load other large immediates from the object
   // pool
   if (object.IsSmi()) {
     // If the raw smi does not fit into a 32-bit signed int, then we'll keep
     // the raw value in the object pool.
     return !Utils::IsInt(32, reinterpret_cast<int64_t>(object.raw()));
   }
   ASSERT(object.IsNotTemporaryScopedHandle());
@@ skipping 39 matching lines @@
   LoadWordFromPoolOffsetFixed(dst, pp, offset);
 }
 
 
 void Assembler::LoadIsolate(Register dst, Register pp) {
   ldr(dst, Address(THR, Thread::isolate_offset()));
 }
 
 
 void Assembler::LoadObject(Register dst, const Object& object, Register pp) {
-  if (CanLoadObjectFromPool(object)) {
+  if (Thread::CanLoadFromThread(object)) {
+    ldr(dst, Address(THR, Thread::OffsetFromThread(object)));
+  } else if (CanLoadFromObjectPool(object)) {
     const int32_t offset =
         ObjectPool::element_offset(object_pool_wrapper_.FindObject(object));
     LoadWordFromPoolOffset(dst, pp, offset);
   } else {
     ASSERT((Isolate::Current() == Dart::vm_isolate()) ||
            object.IsSmi() ||
            object.InVMHeap());
     LoadDecodableImmediate(dst, reinterpret_cast<int64_t>(object.raw()), pp);
   }
 }
 
 
 void Assembler::CompareObject(Register reg, const Object& object, Register pp) {
-  if (CanLoadObjectFromPool(object)) {
+  if (Thread::CanLoadFromThread(object)) {
+    ldr(TMP, Address(THR, Thread::OffsetFromThread(object)));
+    CompareRegisters(reg, TMP);
+  } else if (CanLoadFromObjectPool(object)) {
     LoadObject(TMP, object, pp);
     CompareRegisters(reg, TMP);
   } else {
     CompareImmediate(reg, reinterpret_cast<int64_t>(object.raw()), pp);
   }
 }
 
 
 void Assembler::LoadDecodableImmediate(Register reg, int64_t imm, Register pp) {
   if ((pp != kNoPP) &&
@@ skipping 422 matching lines @@
   }
   // A store buffer update is required.
   if (value != R0) {
     // Preserve R0.
     Push(R0);
   }
   Push(LR);
   if (object != R0) {
     mov(R0, object);
   }
-  StubCode* stub_code = Isolate::Current()->stub_code();
-  BranchLink(&stub_code->UpdateStoreBufferLabel(), PP);
+  ldr(TMP, Address(THR, Thread::update_store_buffer_entry_point_offset()));
+  blr(TMP);
   Pop(LR);
   if (value != R0) {
     // Restore R0.
     Pop(R0);
   }
   Bind(&done);
 }
 
 
 void Assembler::StoreIntoObjectNoBarrier(Register object,
@@ skipping 527 matching lines @@
     add(base, array, Operand(index, LSL, shift));
   }
   const OperandSize size = Address::OperandSizeFor(cid);
   ASSERT(Address::CanHoldOffset(offset, Address::Offset, size));
   return Address(base, offset, Address::Offset, size);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64