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

Port 477e1336

R=mvstanton@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1668233003

Cr-Commit-Position: refs/heads/master@{#33755}

src/ppc/macro-assembler-ppc.cc

@@ -487,6 +487,68 @@ 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(r4));
+  DCHECK(code_entry.is(r7));
+  DCHECK(scratch.is(r8));
+  AssertNotSmi(js_function);
+
+  if (emit_debug_code()) {
+    addi(scratch, js_function, Operand(offset - kHeapObjectTag));
+    LoadP(ip, MemOperand(scratch));
+    cmp(ip, code_entry);
+    Check(eq, kWrongAddressOrValuePassedToRecordWrite);
+  }
+
+  // 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;
+  addi(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());
+  mflr(r0);
+  MultiPush(kJSCallerSaved | r0.bit());
+
+  int argument_count = 3;
+  PrepareCallCFunction(argument_count, code_entry);
+
+  mr(r3, js_function);
+  mr(r4, dst);
+  mov(r5, Operand(ExternalReference::isolate_address(isolate())));
+
+  {
+    AllowExternalCallThatCantCauseGC scope(this);
+    CallCFunction(
+        ExternalReference::incremental_marking_record_write_code_entry_function(
+            isolate()),
+        argument_count);
+  }
+
+  // Restore caller-saved registers (including js_function and code_entry).
+  MultiPop(kJSCallerSaved | r0.bit());
+  mtlr(r0);
+
+  bind(&done);
+}
 
 void MacroAssembler::RememberedSetHelper(Register object,  // For debug tests.
                                          Register address, Register scratch,

src/ppc/macro-assembler-ppc.h

@@ -250,6 +250,11 @@ class MacroAssembler : public Assembler {
                      pointers_to_here_check_for_value);
   }
 
+  // Notify the garbage collector that we wrote a code entry into a
+  // JSFunction. Only scratch is clobbered by the operation.
+  void RecordWriteCodeEntryField(Register js_function, Register code_entry,
+                                 Register scratch);
+
   void RecordWriteForMap(Register object, Register map, Register dst,
                          LinkRegisterStatus lr_status, SaveFPRegsMode save_fp);