Move Assemblers to the Arena.

And clean up some APIs to return std::unique_ptr<> instead
of raw pointers that don't communicate ownership.

Change-Id: I3017302307a0253d661240750298802fb0d9585e
diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index 3efef70..2203646 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -2379,7 +2379,7 @@
 }
 
 void X86Assembler::ExceptionPoll(ManagedRegister /*scratch*/, size_t stack_adjust) {
-  X86ExceptionSlowPath* slow = new X86ExceptionSlowPath(stack_adjust);
+  X86ExceptionSlowPath* slow = new (GetArena()) X86ExceptionSlowPath(stack_adjust);
   buffer_.EnqueueSlowPath(slow);
   fs()->cmpl(Address::Absolute(Thread::ExceptionOffset<4>()), Immediate(0));
   j(kNotEqual, slow->Entry());
@@ -2402,7 +2402,7 @@
 }
 
 void X86Assembler::AddConstantArea() {
-  const std::vector<int32_t>& area = constant_area_.GetBuffer();
+  ArrayRef<const int32_t> area = constant_area_.GetBuffer();
   // Generate the data for the literal area.
   for (size_t i = 0, e = area.size(); i < e; i++) {
     AssemblerBuffer::EnsureCapacity ensured(&buffer_);
diff --git a/compiler/utils/x86/assembler_x86.h b/compiler/utils/x86/assembler_x86.h
index 00ff7bd..8567ad2 100644
--- a/compiler/utils/x86/assembler_x86.h
+++ b/compiler/utils/x86/assembler_x86.h
@@ -18,12 +18,15 @@
 #define ART_COMPILER_UTILS_X86_ASSEMBLER_X86_H_
 
 #include <vector>
+
+#include "base/arena_containers.h"
 #include "base/bit_utils.h"
 #include "base/macros.h"
 #include "constants_x86.h"
 #include "globals.h"
 #include "managed_register_x86.h"
 #include "offsets.h"
+#include "utils/array_ref.h"
 #include "utils/assembler.h"
 
 namespace art {
@@ -260,7 +263,7 @@
  */
 class ConstantArea {
  public:
-  ConstantArea() {}
+  explicit ConstantArea(ArenaAllocator* arena) : buffer_(arena->Adapter(kArenaAllocAssembler)) {}
 
   // Add a double to the constant area, returning the offset into
   // the constant area where the literal resides.
@@ -290,18 +293,18 @@
     return buffer_.size() * elem_size_;
   }
 
-  const std::vector<int32_t>& GetBuffer() const {
-    return buffer_;
+  ArrayRef<const int32_t> GetBuffer() const {
+    return ArrayRef<const int32_t>(buffer_);
   }
 
  private:
   static constexpr size_t elem_size_ = sizeof(int32_t);
-  std::vector<int32_t> buffer_;
+  ArenaVector<int32_t> buffer_;
 };
 
 class X86Assembler FINAL : public Assembler {
  public:
-  X86Assembler() {}
+  explicit X86Assembler(ArenaAllocator* arena) : Assembler(arena), constant_area_(arena) {}
   virtual ~X86Assembler() {}
 
   /*
diff --git a/compiler/utils/x86/assembler_x86_test.cc b/compiler/utils/x86/assembler_x86_test.cc
index d0d5147..1d1df6e 100644
--- a/compiler/utils/x86/assembler_x86_test.cc
+++ b/compiler/utils/x86/assembler_x86_test.cc
@@ -16,13 +16,16 @@
 
 #include "assembler_x86.h"
 
+#include "base/arena_allocator.h"
 #include "base/stl_util.h"
 #include "utils/assembler_test.h"
 
 namespace art {
 
 TEST(AssemblerX86, CreateBuffer) {
-  AssemblerBuffer buffer;
+  ArenaPool pool;
+  ArenaAllocator arena(&pool);
+  AssemblerBuffer buffer(&arena);
   AssemblerBuffer::EnsureCapacity ensured(&buffer);
   buffer.Emit<uint8_t>(0x42);
   ASSERT_EQ(static_cast<size_t>(1), buffer.Size());