Disentangle assembler from isolate.

src/x64/assembler-x64-inl.h

Index: src/x64/assembler-x64-inl.h
diff --git a/src/x64/assembler-x64-inl.h b/src/x64/assembler-x64-inl.h
index 6001dc5e0e3cc3a745f2db1b95f459c7abe54a2b..7deaf23635643e406d15b588dcb54fdd32de5f2f 100644
--- a/src/x64/assembler-x64-inl.h
+++ b/src/x64/assembler-x64-inl.h
@@ -78,8 +78,7 @@ void Assembler::emit_code_target(Handle<Code> target,
 void Assembler::emit_runtime_entry(Address entry, RelocInfo::Mode rmode) {
   DCHECK(RelocInfo::IsRuntimeEntry(rmode));
   RecordRelocInfo(rmode);
-  emitl(static_cast<uint32_t>(
-      entry - isolate()->heap()->memory_allocator()->code_range()->start()));
+  emitl(static_cast<uint32_t>(entry - isolate_data().code_range_start_));
 }
 
 void Assembler::emit(Immediate x) {
@@ -280,6 +279,7 @@ Address Assembler::target_address_at(Address pc, Address constant_pool) {
 void Assembler::set_target_address_at(Isolate* isolate, Address pc,
                                       Address constant_pool, Address target,
                                       ICacheFlushMode icache_flush_mode) {
+  DCHECK_IMPLIES(isolate == nullptr, icache_flush_mode == SKIP_ICACHE_FLUSH);
   Memory::int32_at(pc) = static_cast<int32_t>(target - pc - 4);
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
     Assembler::FlushICache(isolate, pc, sizeof(int32_t));
@@ -319,8 +319,7 @@ Handle<Code> Assembler::code_target_object_handle_at(Address pc) {
 
 
 Address Assembler::runtime_entry_at(Address pc) {
-  return Memory::int32_at(pc) +
-         isolate()->heap()->memory_allocator()->code_range()->start();
+  return Memory::int32_at(pc) + isolate_data().code_range_start_;
 }
 
 // -----------------------------------------------------------------------------
@@ -407,7 +406,7 @@ void RelocInfo::set_target_object(HeapObject* target,
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
   Memory::Object_at(pc_) = target;
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
-    Assembler::FlushICache(isolate_, pc_, sizeof(Address));
+    Assembler::FlushICache(target->GetIsolate(), pc_, sizeof(Address));
   }
   if (write_barrier_mode == UPDATE_WRITE_BARRIER && host() != NULL) {
     host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
@@ -422,13 +421,12 @@ Address RelocInfo::target_runtime_entry(Assembler* origin) {
   return origin->runtime_entry_at(pc_);
 }
 
-
-void RelocInfo::set_target_runtime_entry(Address target,
+void RelocInfo::set_target_runtime_entry(Isolate* isolate, Address target,
                                          WriteBarrierMode write_barrier_mode,
                                          ICacheFlushMode icache_flush_mode) {
   DCHECK(IsRuntimeEntry(rmode_));
   if (target_address() != target) {
-    set_target_address(target, write_barrier_mode, icache_flush_mode);
+    set_target_address(isolate, target, write_barrier_mode, icache_flush_mode);
   }
 }
 
@@ -453,7 +451,7 @@ void RelocInfo::set_target_cell(Cell* cell,
   Address address = cell->address() + Cell::kValueOffset;
   Memory::Address_at(pc_) = address;
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
-    Assembler::FlushICache(isolate_, pc_, sizeof(Address));
+    Assembler::FlushICache(cell->GetIsolate(), pc_, sizeof(Address));
   }
   if (write_barrier_mode == UPDATE_WRITE_BARRIER &&
       host() != NULL) {
@@ -462,14 +460,13 @@ void RelocInfo::set_target_cell(Cell* cell,
   }
 }
 
-
-void RelocInfo::WipeOut() {
+void RelocInfo::WipeOut(Isolate* isolate) {
   if (IsEmbeddedObject(rmode_) || IsExternalReference(rmode_) ||
       IsInternalReference(rmode_)) {
     Memory::Address_at(pc_) = NULL;
   } else if (IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)) {
     // Effectively write zero into the relocation.
-    Assembler::set_target_address_at(isolate_, pc_, host_,
+    Assembler::set_target_address_at(isolate, pc_, host_,
                                      pc_ + sizeof(int32_t));
   } else {
     UNREACHABLE();
@@ -495,8 +492,9 @@ void RelocInfo::set_code_age_stub(Code* stub,
                                   ICacheFlushMode icache_flush_mode) {
   DCHECK(*pc_ == kCallOpcode);
   DCHECK(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
-  Assembler::set_target_address_at(
-      isolate_, pc_ + 1, host_, stub->instruction_start(), icache_flush_mode);
+  Assembler::set_target_address_at(stub->GetIsolate(), pc_ + 1, host_,
+                                   stub->instruction_start(),
+                                   icache_flush_mode);
 }
 
 
@@ -505,12 +503,11 @@ Address RelocInfo::debug_call_address() {
   return Memory::Address_at(pc_ + Assembler::kPatchDebugBreakSlotAddressOffset);
 }
 
-
-void RelocInfo::set_debug_call_address(Address target) {
+void RelocInfo::set_debug_call_address(Isolate* isolate, Address target) {
   DCHECK(IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence());
   Memory::Address_at(pc_ + Assembler::kPatchDebugBreakSlotAddressOffset) =
       target;
-  Assembler::FlushICache(isolate_,
+  Assembler::FlushICache(isolate,
                          pc_ + Assembler::kPatchDebugBreakSlotAddressOffset,
                          sizeof(Address));
   if (host() != NULL) {