Enable preaging of code objects when --optimize-for-size.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 3becc96d262513378f31b3d5ebc7fcf5d62e3f54..0a834019903fdfaf34bf7476cf8a25337843ee9e 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -168,10 +168,18 @@ void FullCodeGenerator::Generate() {
         masm_, kNoCodeAgeSequenceLength * Assembler::kInstrSize);
     // The following three instructions must remain together and unmodified
     // for code aging to work properly.
-    __ stm(db_w, sp, r1.bit() | cp.bit() | fp.bit() | lr.bit());
-    __ nop(ip.code());
-    // Adjust FP to point to saved FP.
-    __ add(fp, sp, Operand(2 * kPointerSize));
+    if (FLAG_optimize_for_size && FLAG_age_code) {
+      // Pre-age the code.
+      Code* stub = Code::GetPreAgedCodeAgeStub(isolate());
+      __ add(r0, pc, Operand(-8));
+      __ ldr(pc, MemOperand(pc, -4));
+      __ dd(reinterpret_cast<uint32_t>(stub->instruction_start()));
+    } else {
+      __ stm(db_w, sp, r1.bit() | cp.bit() | fp.bit() | lr.bit());
+      __ nop(ip.code());
+      // Adjust FP to point to saved FP.
+      __ add(fp, sp, Operand(2 * kPointerSize));
+    }
   }
   info->AddNoFrameRange(0, masm_->pc_offset());