Optimize AOT's switchable calls for the monomorphic case.

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 2014 matching lines @@
   __ LoadFromOffset(right, SP, 0 * kWordSize);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
 }
 
 
 // Called from megamorphic calls.
 //  R0: receiver
 //  R5: MegamorphicCache (preserved)
 // Result:
-//  R1: target entry point
 //  CODE_REG: target Code
 //  R4: arguments descriptor
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
+  __ NoMonomorphicCheckedEntry();
+
   // Jump if receiver is a smi.
   Label smi_case;
   __ TestImmediate(R0, kSmiTagMask);
   __ b(&smi_case, EQ);
 
   // Loads the cid of the object.
   __ LoadClassId(R0, R0);
 
   Label cid_loaded;
   __ Bind(&cid_loaded);
@@ skipping 27 matching lines @@
   Label load_target;
   __ Bind(&load_target);
   // Call the target found in the cache.  For a class id match, this is a
   // proper target for the given name and arguments descriptor.  If the
   // illegal class id was found, the target is a cache miss handler that can
   // be invoked as a normal Dart function.
   __ ldr(R0, FieldAddress(TMP, base + kWordSize));
   __ ldr(R4, FieldAddress(R5, MegamorphicCache::arguments_descriptor_offset()));
   __ ldr(R1, FieldAddress(R0, Function::entry_point_offset()));
   __ ldr(CODE_REG, FieldAddress(R0, Function::code_offset()));
-  __ ret();
+  __ br(R1);
 
   // Probe failed, check if it is a miss.
   __ Bind(&probe_failed);
   ASSERT(kIllegalCid == 0);
   __ tst(R6, Operand(R6));
   __ b(&load_target, EQ);  // branch if miss.
 
   // Try next extry in the table.
   __ AddImmediate(R3, R3, Smi::RawValue(1));
   __ b(&loop);
 
   // Load cid for the Smi case.
   __ Bind(&smi_case);
   __ LoadImmediate(R0, kSmiCid);
   __ b(&cid_loaded);
 }
 
 
 // Called from switchable IC calls.
 //  R0: receiver
 //  R5: ICData (preserved)
 // Result:
-//  R1: target entry point
 //  CODE_REG: target Code object
 //  R4: arguments descriptor
 void StubCode::GenerateICLookupThroughFunctionStub(Assembler* assembler) {
+  __ NoMonomorphicCheckedEntry();
+
   Label loop, found, miss;
   __ ldr(R4, FieldAddress(R5, ICData::arguments_descriptor_offset()));
   __ ldr(R8, FieldAddress(R5, ICData::ic_data_offset()));
   __ AddImmediate(R8, R8, Array::data_offset() - kHeapObjectTag);
   // R8: first IC entry
   __ LoadTaggedClassIdMayBeSmi(R1, R0);
   // R1: receiver cid as Smi
 
   __ Bind(&loop);
   __ ldr(R2, Address(R8, 0));
   __ cmp(R1, Operand(R2));
   __ b(&found, EQ);
   __ CompareImmediate(R2, Smi::RawValue(kIllegalCid));
   __ b(&miss, EQ);
 
   const intptr_t entry_length = ICData::TestEntryLengthFor(1) * kWordSize;
   __ AddImmediate(R8, R8, entry_length);  // Next entry.
   __ b(&loop);
 
   __ Bind(&found);
   const intptr_t target_offset = ICData::TargetIndexFor(1) * kWordSize;
   __ ldr(R0, Address(R8, target_offset));
   __ ldr(R1, FieldAddress(R0, Function::entry_point_offset()));
   __ ldr(CODE_REG, FieldAddress(R0, Function::code_offset()));
-  __ ret();
+  __ br(R1);
 
   __ Bind(&miss);
   __ LoadIsolate(R2);
   __ ldr(CODE_REG, Address(R2, Isolate::ic_miss_code_offset()));
   __ ldr(R1, FieldAddress(CODE_REG, Code::entry_point_offset()));
-  __ ret();
+  __ br(R1);
 }
 
 
 void StubCode::GenerateICLookupThroughCodeStub(Assembler* assembler) {
+  __ NoMonomorphicCheckedEntry();
+
   Label loop, found, miss;
   __ ldr(R4, FieldAddress(R5, ICData::arguments_descriptor_offset()));
   __ ldr(R8, FieldAddress(R5, ICData::ic_data_offset()));
   __ AddImmediate(R8, R8, Array::data_offset() - kHeapObjectTag);
   // R8: first IC entry
   __ LoadTaggedClassIdMayBeSmi(R1, R0);
   // R1: receiver cid as Smi
 
   __ Bind(&loop);
   __ ldr(R2, Address(R8, 0));
   __ cmp(R1, Operand(R2));
   __ b(&found, EQ);
   __ CompareImmediate(R2, Smi::RawValue(kIllegalCid));
   __ b(&miss, EQ);
 
   const intptr_t entry_length = ICData::TestEntryLengthFor(1) * kWordSize;
   __ AddImmediate(R8, R8, entry_length);  // Next entry.
   __ b(&loop);
 
   __ Bind(&found);
   const intptr_t code_offset = ICData::CodeIndexFor(1) * kWordSize;
   const intptr_t entry_offset = ICData::EntryPointIndexFor(1) * kWordSize;
   __ ldr(R1, Address(R8, entry_offset));
   __ ldr(CODE_REG, Address(R8, code_offset));
-  __ ret();
+  __ br(R1);
 
   __ Bind(&miss);
   __ LoadIsolate(R2);
   __ ldr(CODE_REG, Address(R2, Isolate::ic_miss_code_offset()));
   __ ldr(R1, FieldAddress(CODE_REG, Code::entry_point_offset()));
-  __ ret();
+  __ br(R1);
 }
 
 
+// Called from the monomorphic checked entry.
+//  R0: receiver
+void StubCode::GenerateMonomorphicMissStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  __ Push(R0);  // Preserve receiver.
+
+  __ PushObject(Object::null_object());  // Result.
+  __ Push(R0);                           // Arg0: Receiver
+  __ CallRuntime(kMonomorphicMissRuntimeEntry, 1);
+  __ Drop(1);
+  __ Pop(R5);  // result = IC
+
+  __ Pop(R0);  // Restore receiver.
+  __ LeaveStubFrame();
+
+  __ ldr(CODE_REG, Address(THR, Thread::ic_lookup_through_code_stub_offset()));
+  __ ldr(R1, FieldAddress(CODE_REG, Code::checked_entry_point_offset()));
+  __ br(R1);
+}
+
+
 void StubCode::GenerateFrameAwaitingMaterializationStub(Assembler* assembler) {
   __ brk(0);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64