Cleanup of class id loading sequences.

runtime/vm/stub_code_arm.cc

 // Copyright (c) 2013, 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_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 1245 matching lines @@
     // Check single stepping.
     __ ldr(R6, FieldAddress(CTX, Context::isolate_offset()));
     __ ldrb(R6, Address(R6, Isolate::single_step_offset()));
     __ CompareImmediate(R6, 0);
     __ b(&stepping, NE);
     __ Bind(&done_stepping);
   }
 
   // Load arguments descriptor into R4.
   __ ldr(R4, FieldAddress(R5, ICData::arguments_descriptor_offset()));
-  // Preserve return address, since LR is needed for subroutine call.
-  __ mov(R8, Operand(LR));
   // Loop that checks if there is an IC data match.
   Label loop, update, test, found;
   // R5: IC data object (preserved).
   __ ldr(R6, FieldAddress(R5, ICData::ic_data_offset()));
   // R6: ic_data_array with check entries: classes and target functions.
   __ AddImmediate(R6, R6, Array::data_offset() - kHeapObjectTag);
   // R6: points directly to the first ic data array element.
 
   // Get the receiver's class ID (first read number of arguments from
   // arguments descriptor array and then access the receiver from the stack).
@@ skipping 15 matching lines @@
       __ LoadTaggedClassIdMayBeSmi(R0, R0);
       // R0: next argument class ID (smi).
       __ LoadFromOffset(kWord, R1, R6, i * kWordSize);
       // R1: next class ID to check (smi).
     }
     __ cmp(R0, Operand(R1));  // Class id match?
     if (i < (num_args - 1)) {
       __ b(&update, NE);  // Continue.
     } else {
       // Last check, all checks before matched.
-      __ mov(LR, Operand(R8), EQ);  // Restore return address if found.
       __ b(&found, EQ);  // Break.
     }
   }
   __ Bind(&update);
   // Reload receiver class ID.  It has not been destroyed when num_args == 1.
   if (num_args > 1) {
     __ ldr(R0, Address(SP, R7, LSL, 1));
     __ LoadTaggedClassIdMayBeSmi(R0, R0);
   }
 
   const intptr_t entry_size = ICData::TestEntryLengthFor(num_args) * kWordSize;
   __ AddImmediate(R6, entry_size);  // Next entry.
   __ ldr(R1, Address(R6, 0));  // Next class ID.
 
   __ Bind(&test);
   __ CompareImmediate(R1, Smi::RawValue(kIllegalCid));  // Done?
   __ b(&loop, NE);
 
   // IC miss.
-  // Restore return address.
-  __ mov(LR, Operand(R8));
-
   // Compute address of arguments.
   // R7: argument_count - 1 (smi).
   __ add(R7, SP, Operand(R7, LSL, 1));  // R7 is Smi.
   // R7: address of receiver.
   // Create a stub frame as we are pushing some objects on the stack before
   // calling into the runtime.
   __ EnterStubFrame();
   __ LoadImmediate(R0, reinterpret_cast<intptr_t>(Object::null()));
   // Preserve IC data object and arguments descriptor array and
   // setup space on stack for result (target code object).
@@ skipping 536 matching lines @@
   const Register right = R0;
   __ ldr(left, Address(SP, 1 * kWordSize));
   __ ldr(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM