commit 4717175e40a19e79af904dfb7b7dd13f046debd7
author Nicolas Geoffray <ngeoffray@google.com> Mon Aug 31 15:03:20 2020 +0100
committer Nicolas Geoffray <ngeoffray@google.com> Mon Sep 07 07:29:59 2020 +0000
tree 426f040eacf5a8305f8bb8d504bd509824d984c8
parent 1faacf59b9f74e9d2de4e0331ef0cdfcf132225d

Move code item to the data pointer and remove code_item_offset.

This saves 4 bytes on 32bit and 8 bytes on 64bit on ArtMethod.

Also update nterp to directly fetch the code item from the data pointer.

Test: test.py
Bug: 112676029

Change-Id: Ic01f43c7ccf2cbce1ec517478e81362232d36371

runtime/class_linker.cc

diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 09fa99b..c181c22 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -2199,10 +2199,21 @@
     }, space->Begin(), image_pointer_size_);
   }
 
-  if (interpreter::CanRuntimeUseNterp()) {
-    // Set image methods' entry point that point to the interpreter bridge to the nterp entry point.
+  if (!runtime->IsAotCompiler()) {
+    bool can_use_nterp = interpreter::CanRuntimeUseNterp();
     header.VisitPackedArtMethods([&](ArtMethod& method) REQUIRES_SHARED(Locks::mutator_lock_) {
-      ChangeInterpreterBridgeToNterp(&method, this);
+      // In the image, the `data` pointer field of the ArtMethod contains the code
+      // item offset. Change this to the actual pointer to the code item.
+      if (method.HasCodeItem()) {
+        const dex::CodeItem* code_item = method.GetDexFile()->GetCodeItem(
+            reinterpret_cast32<uint32_t>(method.GetDataPtrSize(image_pointer_size_)));
+        method.SetDataPtrSize(code_item, image_pointer_size_);
+      }
+      // Set image methods' entry point that point to the interpreter bridge to the
+      // nterp entry point.
+      if (can_use_nterp) {
+        ChangeInterpreterBridgeToNterp(&method, this);
+      }
     }, space->Begin(), image_pointer_size_);
   }
 
@@ -3977,7 +3988,6 @@
   ScopedAssertNoThreadSuspension ants("LoadMethod");
   dst->SetDexMethodIndex(dex_method_idx);
   dst->SetDeclaringClass(klass.Get());
-  dst->SetCodeItemOffset(method.GetCodeItemOffset());
 
   // Get access flags from the DexFile and set hiddenapi runtime access flags.
   uint32_t access_flags = method.GetAccessFlags() | hiddenapi::CreateRuntimeFlags(method);
@@ -4026,6 +4036,18 @@
   if (klass->IsInterface() && dst->IsAbstract()) {
     dst->CalculateAndSetImtIndex();
   }
+  if (dst->HasCodeItem()) {
+    DCHECK_NE(method.GetCodeItemOffset(), 0u);
+    if (Runtime::Current()->IsAotCompiler()) {
+      dst->SetDataPtrSize(reinterpret_cast32<void*>(method.GetCodeItemOffset()), image_pointer_size_);
+    } else {
+      dst->SetDataPtrSize(dst->GetDexFile()->GetCodeItem(method.GetCodeItemOffset()),
+                          image_pointer_size_);
+    }
+  } else {
+    dst->SetDataPtrSize(nullptr, image_pointer_size_);
+    DCHECK_EQ(method.GetCodeItemOffset(), 0u);
+  }
 }
 
 void ClassLinker::AppendToBootClassPath(Thread* self, const DexFile* dex_file) {
@@ -5304,10 +5326,6 @@
   const uint32_t kAddFlags = kAccFinal | kAccCompileDontBother;
   out->SetAccessFlags((out->GetAccessFlags() & ~kRemoveFlags) | kAddFlags);
 
-  // Clear the dex_code_item_offset_. It needs to be 0 since proxy methods have no CodeItems but the
-  // method they copy might (if it's a default method).
-  out->SetCodeItemOffset(0);
-
   // Set the original interface method.
   out->SetDataPtrSize(prototype, image_pointer_size_);