More compact string representation on 64 bit.

runtime/vm/intrinsifier_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"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 158 matching lines @@
   __ tst(R2, Operand(kSmiTagMask));                                            \
   __ b(&fall_through, NE);                                                     \
   __ CompareImmediate(R2, 0);                                                  \
   __ b(&fall_through, LT);                                                     \
   __ SmiUntag(R2);                                                             \
   /* Check for maximum allowed length. */                                      \
   /* R2: untagged array length. */                                             \
   __ CompareImmediate(R2, max_len);                                            \
   __ b(&fall_through, GT);                                                     \
   __ mov(R2, Operand(R2, LSL, scale_shift));                                   \
-  const intptr_t fixed_size = sizeof(Raw##type_name) + kObjectAlignment - 1;   \
-  __ AddImmediate(R2, fixed_size);                                             \
+  const intptr_t fixed_size_plus_alignment_padding =                           \
+      sizeof(Raw##type_name) + kObjectAlignment - 1;                           \
+  __ AddImmediate(R2, fixed_size_plus_alignment_padding);                      \
   __ bic(R2, R2, Operand(kObjectAlignment - 1));                               \
   Heap::Space space = Heap::kNew;                                              \
   __ ldr(R3, Address(THR, Thread::heap_offset()));                             \
   __ ldr(R0, Address(R3, Heap::TopOffset(space)));                             \
                                                                                \
   /* R2: allocation size. */                                                   \
   __ adds(R1, R0, Operand(R2));                                                \
   __ b(&fall_through, CS); /* Fail on unsigned overflow. */                    \
                                                                                \
   /* Check if the allocation fits into the remaining space. */                 \
@@ skipping 1799 matching lines @@
 // Returns new string as tagged pointer in R0.
 static void TryAllocateOnebyteString(Assembler* assembler,
                                      Label* ok,
                                      Label* failure) {
   const Register length_reg = R2;
   Label fail;
   NOT_IN_PRODUCT(__ MaybeTraceAllocation(kOneByteStringCid, R0, failure));
   __ mov(R8, Operand(length_reg));  // Save the length register.
   // TODO(koda): Protect against negative length and overflow here.
   __ SmiUntag(length_reg);
-  const intptr_t fixed_size = sizeof(RawString) + kObjectAlignment - 1;
-  __ AddImmediate(length_reg, fixed_size);
+  const intptr_t fixed_size_plus_alignment_padding =
+      sizeof(RawString) + kObjectAlignment - 1;
+  __ AddImmediate(length_reg, fixed_size_plus_alignment_padding);
   __ bic(length_reg, length_reg, Operand(kObjectAlignment - 1));
 
   const intptr_t cid = kOneByteStringCid;
   Heap::Space space = Heap::kNew;
   __ ldr(R3, Address(THR, Thread::heap_offset()));
   __ ldr(R0, Address(R3, Heap::TopOffset(space)));
 
   // length_reg: allocation size.
   __ adds(R1, R0, Operand(length_reg));
   __ b(&fail, CS);  // Fail on unsigned overflow.
@@ skipping 298 matching lines @@
 
 void Intrinsifier::SetAsyncThreadStackTrace(Assembler* assembler) {
   __ ldr(R0, Address(THR, Thread::async_stack_trace_offset()));
   __ LoadObject(R0, Object::null_object());
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM