Move ArtField to native

Add linear alloc. Moved ArtField to be native object. Changed image
writer to put ArtFields after the mirror section.

Savings:
2MB on low ram devices
4MB on normal devices

Total PSS measurements before (normal N5, 95s after shell start):
Image size: 7729152 bytes
23112 kB: .NonMoving
23212 kB: .NonMoving
22868 kB: .NonMoving
23072 kB: .NonMoving
22836 kB: .NonMoving
19618 kB: .Zygote
19850 kB: .Zygote
19623 kB: .Zygote
19924 kB: .Zygote
19612 kB: .Zygote
Avg: 42745.4 kB

After:
Image size: 7462912 bytes
17440 kB: .NonMoving
16776 kB: .NonMoving
16804 kB: .NonMoving
17812 kB: .NonMoving
16820 kB: .NonMoving
18788 kB: .Zygote
18856 kB: .Zygote
19064 kB: .Zygote
18841 kB: .Zygote
18629 kB: .Zygote
3499 kB: .LinearAlloc
3408 kB: .LinearAlloc
3424 kB: .LinearAlloc
3600 kB: .LinearAlloc
3436 kB: .LinearAlloc
Avg: 39439.4 kB

No reflection performance changes.

Bug: 19264997
Bug: 17643507

Change-Id: I10c73a37913332080aeb978c7c94713bdfe4fe1c

1 files changed, 11 insertions, 0 deletions

diff --git a/runtime/runtime.h b/runtime/runtime.h
index baa4d18da8..d95640dea6 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -42,6 +42,7 @@ namespace art {
 
 class ArenaPool;
 class CompilerCallbacks;
+class LinearAlloc;
 
 namespace gc {
   class Heap;
@@ -549,6 +550,9 @@ class Runtime {
   const ArenaPool* GetArenaPool() const {
     return arena_pool_.get();
   }
+  LinearAlloc* GetLinearAlloc() {
+    return linear_alloc_.get();
+  }
 
   jit::JitOptions* GetJITOptions() {
     return jit_options_.get();
@@ -618,6 +622,13 @@ class Runtime {
   gc::Heap* heap_;
 
   std::unique_ptr<ArenaPool> arena_pool_;
+  // Special low 4gb pool for compiler linear alloc. We need ArtFields to be in low 4gb if we are
+  // compiling using a 32 bit image on a 64 bit compiler in case we resolve things in the image
+  // since the field arrays are int arrays in this case.
+  std::unique_ptr<ArenaPool> low_4gb_arena_pool_;
+
+  // Shared linear alloc for now.
+  std::unique_ptr<LinearAlloc> linear_alloc_;
 
   // The number of spins that are done before thread suspension is used to forcibly inflate.
   size_t max_spins_before_thin_lock_inflation_;