Precompilation: Generate instance calls as IC calls that can switch to Megamoprhic calls.

runtime/vm/instructions_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"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/constants_arm64.h"
 #include "vm/cpu.h"
@@ skipping 311 matching lines @@
   movk1->SetMoveWideBits(MOVK, IP0, h1, 1, kDoubleWord);
   movk2->SetMoveWideBits(MOVK, IP0, h2, 2, kDoubleWord);
   movk3->SetMoveWideBits(MOVK, IP0, h3, 3, kDoubleWord);
   blr->SetUnconditionalBranchRegBits(BLR, IP0);
 
   ASSERT(kDeoptCallLengthInBytes == 5 * Instr::kInstrSize);
   CPU::FlushICache(pc, kDeoptCallLengthInBytes);
 }
 
 
+SwitchableCallPattern::SwitchableCallPattern(uword pc, const Code& code)
+    : object_pool_(ObjectPool::Handle(code.GetObjectPool())),
+      cache_pool_index_(-1),
+      stub_pool_index_(-1) {
+  ASSERT(code.ContainsInstructionAt(pc));
+  // Last instruction: blr r1.
+  ASSERT(*(reinterpret_cast<uint32_t*>(pc) - 1) == 0xd63f0020);
+
+  Register reg;
+  uword stub_load_end =
+      InstructionPattern::DecodeLoadWordFromPool(pc - 3 * Instr::kInstrSize,
+                                                 &reg,
+                                                 &stub_pool_index_);
+  ASSERT(reg == CODE_REG);
+  InstructionPattern::DecodeLoadWordFromPool(stub_load_end,
+                                             &reg,
+                                             &cache_pool_index_);
+  ASSERT(reg == R5);
+}
+
+
+RawObject* SwitchableCallPattern::cache() const {
+  return reinterpret_cast<RawCode*>(
+      object_pool_.ObjectAt(cache_pool_index_));
+}
+
+
+void SwitchableCallPattern::SetCache(const MegamorphicCache& cache) const {
+  ASSERT(Object::Handle(object_pool_.ObjectAt(cache_pool_index_)).IsICData());
+  object_pool_.SetObjectAt(cache_pool_index_, cache);
+}
+
+
+void SwitchableCallPattern::SetLookupStub(const Code& lookup_stub) const {
+  ASSERT(Object::Handle(object_pool_.ObjectAt(stub_pool_index_)).IsCode());
+  object_pool_.SetObjectAt(stub_pool_index_, lookup_stub);
+}
+
+
 ReturnPattern::ReturnPattern(uword pc)
     : pc_(pc) {
 }
 
 
 bool ReturnPattern::IsValid() const {
   Instr* bx_lr = Instr::At(pc_);
   const Register crn = ConcreteRegister(LR);
   const int32_t instruction = RET | (static_cast<int32_t>(crn) << kRnShift);
   return bx_lr->InstructionBits() == instruction;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64