Write barrier for storing a code entry, and usage in CompileLazy builtin.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 0afe5157d6742c1128162dcb0ab2842f872d0173..802777aa60c4b2048cd55e1a39faadeea1008b12 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -369,6 +369,67 @@ void MacroAssembler::RecordWrite(
   }
 }
 
+void MacroAssembler::RecordWriteCodeEntryField(Register js_function,
+                                               Register code_entry,
+                                               Register scratch) {
+  const int offset = JSFunction::kCodeEntryOffset;
+
+  // Since a code entry (value) is always in old space, we don't need to update
+  // remembered set. If incremental marking is off, there is nothing for us to
+  // do.
+  if (!FLAG_incremental_marking) return;
+
+  DCHECK(js_function.is(a1));
+  DCHECK(code_entry.is(t0));
+  DCHECK(scratch.is(t1));
+  AssertNotSmi(js_function);
+
+  if (emit_debug_code()) {
+    Addu(scratch, js_function, Operand(offset - kHeapObjectTag));
+    lw(at, MemOperand(scratch));
+    Assert(eq, kWrongAddressOrValuePassedToRecordWrite, at,
+           Operand(code_entry));
+  }
+
+  // First, check if a write barrier is even needed. The tests below
+  // catch stores of Smis and stores into young gen.
+  Label done;
+
+  CheckPageFlag(code_entry, scratch,
+                MemoryChunk::kPointersToHereAreInterestingMask, eq, &done);
+  CheckPageFlag(js_function, scratch,
+                MemoryChunk::kPointersFromHereAreInterestingMask, eq, &done);
+
+  const Register dst = scratch;
+  Addu(dst, js_function, Operand(offset - kHeapObjectTag));
+
+  // Save caller-saved registers. js_function and code_entry are in the
+  // caller-saved register list.
+  DCHECK(kJSCallerSaved & js_function.bit());
+  DCHECK(kJSCallerSaved & code_entry.bit());
+  MultiPush(kJSCallerSaved | ra.bit());
+
+  int argument_count = 3;
+
+  PrepareCallCFunction(argument_count, 0, code_entry);
+
+  mov(a0, js_function);
+  mov(a1, dst);
+  li(a2, Operand(ExternalReference::isolate_address(isolate())));
+
+  {
+    AllowExternalCallThatCantCauseGC scope(this);
+    CallCFunction(
+        ExternalReference::incremental_marking_record_write_code_entry_function(
+            isolate()),
+        argument_count);
+  }
+
+  // Restore caller-saved registers.
+  MultiPop(kJSCallerSaved | ra.bit());
+
+  bind(&done);
+}
 
 void MacroAssembler::RememberedSetHelper(Register object,  // For debug tests.
                                          Register address,