Disentangle assembler from isolate.

src/x87/assembler-x87-inl.h

Index: src/x87/assembler-x87-inl.h
diff --git a/src/x87/assembler-x87-inl.h b/src/x87/assembler-x87-inl.h
index b175fd55db51d777d854497f65c1159d85ea8f4f..c1af7d06d216e9748791115b8f2ecd5637a04d3e 100644
--- a/src/x87/assembler-x87-inl.h
+++ b/src/x87/assembler-x87-inl.h
@@ -101,33 +101,28 @@ int RelocInfo::target_address_size() {
   return Assembler::kSpecialTargetSize;
 }
 
-
-Object* RelocInfo::target_object() {
+HeapObject* RelocInfo::target_object() {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
-  return Memory::Object_at(pc_);
+  return HeapObject::cast(Memory::Object_at(pc_));
 }
 
-
-Handle<Object> RelocInfo::target_object_handle(Assembler* origin) {
+Handle<HeapObject> RelocInfo::target_object_handle(Assembler* origin) {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
-  return Memory::Object_Handle_at(pc_);
+  return Handle<HeapObject>::cast(Memory::Object_Handle_at(pc_));
 }
 
-
-void RelocInfo::set_target_object(Object* target,
+void RelocInfo::set_target_object(HeapObject* target,
                                   WriteBarrierMode write_barrier_mode,
                                   ICacheFlushMode icache_flush_mode) {
   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 &&
-      target->IsHeapObject()) {
+  if (write_barrier_mode == UPDATE_WRITE_BARRIER && host() != nullptr) {
     host()->GetHeap()->RecordWriteIntoCode(host(), this, target);
-    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
-        host(), this, HeapObject::cast(target));
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
+                                                                  target);
   }
 }
 
@@ -155,13 +150,12 @@ Address RelocInfo::target_runtime_entry(Assembler* origin) {
   return reinterpret_cast<Address>(*reinterpret_cast<int32_t*>(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);
   }
 }
 
@@ -187,7 +181,7 @@ 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) {
     host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
@@ -195,11 +189,10 @@ void RelocInfo::set_target_cell(Cell* cell,
   }
 }
 
-
-Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
+Handle<Code> RelocInfo::code_age_stub_handle(Assembler* origin) {
   DCHECK(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
   DCHECK(*pc_ == kCallOpcode);
-  return Memory::Object_Handle_at(pc_ + 1);
+  return Handle<Code>::cast(Memory::Object_Handle_at(pc_ + 1));
 }
 
 
@@ -215,8 +208,9 @@ 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);
 }
 
 
@@ -226,11 +220,10 @@ Address RelocInfo::debug_call_address() {
   return Assembler::target_address_at(location, host_);
 }
 
-
-void RelocInfo::set_debug_call_address(Address target) {
+void RelocInfo::set_debug_call_address(Isolate* isolate, Address target) {
   DCHECK(IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence());
   Address location = pc_ + Assembler::kPatchDebugBreakSlotAddressOffset;
-  Assembler::set_target_address_at(isolate_, location, host_, target);
+  Assembler::set_target_address_at(isolate, location, host_, target);
   if (host() != NULL) {
     Code* target_code = Code::GetCodeFromTargetAddress(target);
     host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
@@ -238,14 +231,13 @@ void RelocInfo::set_debug_call_address(Address target) {
   }
 }
 
-
-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();
@@ -440,6 +432,7 @@ 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);
   int32_t* p = reinterpret_cast<int32_t*>(pc);
   *p = target - (pc + sizeof(int32_t));
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {