diff --git a/patchoat/patchoat.h b/patchoat/patchoat.h
index 5a3545b..578df3a 100644
--- a/patchoat/patchoat.h
+++ b/patchoat/patchoat.h
@@ -61,15 +61,16 @@
   // Takes ownership only of the ElfFile. All other pointers are only borrowed.
   PatchOat(ElfFile* oat_file, off_t delta, TimingLogger* timings)
       : oat_file_(oat_file), image_(nullptr), bitmap_(nullptr), heap_(nullptr), delta_(delta),
-        timings_(timings) {}
-  PatchOat(MemMap* image, gc::accounting::ContinuousSpaceBitmap* bitmap,
+        isa_(kNone), timings_(timings) {}
+  PatchOat(InstructionSet isa, MemMap* image, gc::accounting::ContinuousSpaceBitmap* bitmap,
            MemMap* heap, off_t delta, TimingLogger* timings)
       : image_(image), bitmap_(bitmap), heap_(heap),
-        delta_(delta), timings_(timings) {}
-  PatchOat(ElfFile* oat_file, MemMap* image, gc::accounting::ContinuousSpaceBitmap* bitmap,
-           MemMap* heap, off_t delta, TimingLogger* timings)
+        delta_(delta), isa_(isa), timings_(timings) {}
+  PatchOat(InstructionSet isa, ElfFile* oat_file, MemMap* image,
+           gc::accounting::ContinuousSpaceBitmap* bitmap, MemMap* heap, off_t delta,
+           TimingLogger* timings)
       : oat_file_(oat_file), image_(image), bitmap_(bitmap), heap_(heap),
-        delta_(delta), timings_(timings) {}
+        delta_(delta), isa_(isa), timings_(timings) {}
   ~PatchOat() {}
 
   // Was the .art image at image_path made with --compile-pic ?
@@ -156,8 +157,10 @@
   const MemMap* const heap_;
   // The amount we are changing the offset by.
   const off_t delta_;
-  // Timing splits.
-  TimingLogger* const timings_;
+  // Active instruction set, used to know the entrypoint size.
+  const InstructionSet isa_;
+
+  TimingLogger* timings_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PatchOat);
 };