Moves the top_ and end_ words of the Scavenger into mutator thread.

runtime/vm/intrinsifier_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/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 182 matching lines @@
   __ SmiUntag(R2);                                                             \
   /* Check for maximum allowed length. */                                      \
   /* R2: untagged array length. */                                             \
   __ CompareImmediate(R2, max_len);                                            \
   __ b(&fall_through, GT);                                                     \
   __ LslImmediate(R2, R2, scale_shift);                                        \
   const intptr_t fixed_size_plus_alignment_padding =                           \
       sizeof(Raw##type_name) + kObjectAlignment - 1;                           \
   __ AddImmediate(R2, fixed_size_plus_alignment_padding);                      \
   __ andi(R2, R2, Immediate(~(kObjectAlignment - 1)));                         \
-  Heap::Space space = Heap::kNew;                                              \
-  __ ldr(R3, Address(THR, Thread::heap_offset()));                             \
-  __ ldr(R0, Address(R3, Heap::TopOffset(space)));                             \
+  NOT_IN_PRODUCT(Heap::Space space = Heap::kNew);                              \
+  __ ldr(R0, Address(THR, Thread::top_offset()));                              \
                                                                                \
   /* 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. */                 \
   /* R0: potential new object start. */                                        \
   /* R1: potential next object start. */                                       \
   /* R2: allocation size. */                                                   \
-  /* R3: heap. */                                                              \
-  __ ldr(R6, Address(R3, Heap::EndOffset(space)));                             \
+  __ ldr(R6, Address(THR, Thread::end_offset()));                              \
   __ cmp(R1, Operand(R6));                                                     \
   __ b(&fall_through, CS);                                                     \
                                                                                \
   /* Successfully allocated the object(s), now update top to point to */       \
   /* next object start and initialize the object. */                           \
-  __ str(R1, Address(R3, Heap::TopOffset(space)));                             \
+  __ str(R1, Address(THR, Thread::top_offset()));                              \
   __ AddImmediate(R0, kHeapObjectTag);                                         \
   NOT_IN_PRODUCT(__ UpdateAllocationStatsWithSize(cid, R2, space));            \
   /* Initialize the tags. */                                                   \
   /* R0: new object start as a tagged pointer. */                              \
   /* R1: new object end address. */                                            \
   /* R2: allocation size. */                                                   \
   {                                                                            \
     __ CompareImmediate(R2, RawObject::SizeTag::kMaxSizeTag);                  \
     __ LslImmediate(R2, R2, RawObject::kSizeTagPos - kObjectAlignmentLog2);    \
     __ csel(R2, ZR, R2, HI);                                                   \
@@ skipping 1855 matching lines @@
   // and cannot be externalized.  TODO(erikcorry): We should probably just
   // return a static zero length string here instead.
   // length <- (length != 0) ? length : (ZR + 1).
   __ csinc(length_reg, length_reg, ZR, NE);
   const intptr_t fixed_size_plus_alignment_padding =
       sizeof(RawString) + kObjectAlignment - 1;
   __ AddImmediate(length_reg, fixed_size_plus_alignment_padding);
   __ andi(length_reg, length_reg, Immediate(~(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)));
+  NOT_IN_PRODUCT(Heap::Space space = Heap::kNew);
+  __ ldr(R0, Address(THR, Thread::top_offset()));
 
   // length_reg: allocation size.
   __ adds(R1, R0, Operand(length_reg));
   __ b(&fail, CS);  // Fail on unsigned overflow.
 
   // Check if the allocation fits into the remaining space.
   // R0: potential new object start.
   // R1: potential next object start.
   // R2: allocation size.
-  // R3: heap.
-  __ ldr(R7, Address(R3, Heap::EndOffset(space)));
+  __ ldr(R7, Address(THR, Thread::end_offset()));
   __ cmp(R1, Operand(R7));
   __ b(&fail, CS);
 
   // Successfully allocated the object(s), now update top to point to
   // next object start and initialize the object.
-  __ str(R1, Address(R3, Heap::TopOffset(space)));
+  __ str(R1, Address(THR, Thread::top_offset()));
   __ AddImmediate(R0, kHeapObjectTag);
   NOT_IN_PRODUCT(__ UpdateAllocationStatsWithSize(cid, R2, space));
 
   // Initialize the tags.
   // R0: new object start as a tagged pointer.
   // R1: new object end address.
   // R2: allocation size.
   {
     const intptr_t shift = RawObject::kSizeTagPos - kObjectAlignmentLog2;
 
@@ skipping 272 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_ARM64