Subzero. Performance tweaks.

src/IceAssembler.h

 //===- subzero/src/IceAssembler.h - Integrated assembler --------*- C++ -*-===//
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
 //                        The Subzero Code Generator
@@ skipping 12 matching lines @@
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEASSEMBLER_H
 #define SUBZERO_SRC_ICEASSEMBLER_H
 
 #include "IceDefs.h"
 #include "IceFixups.h"
 #include "IceUtils.h"
 
+#include "llvm/Support/Allocator.h"
+
 namespace Ice {
 
 class Assembler;
 
 /// A Label can be in one of three states:
 ///  - Unused.
 ///  - Linked, unplaced and tracking the position of branches to the label.
 ///  - Bound, placed and tracking its position.
 class Label {
   Label(const Label &) = delete;
@@ skipping 288 matching lines @@
 
   AssemblerKind getKind() const { return Kind; }
 
 protected:
   explicit Assembler(AssemblerKind Kind)
       : Kind(Kind), Allocator(), Buffer(*this) {}
 
 private:
   const AssemblerKind Kind;
 
-  ArenaAllocator<32 * 1024> Allocator;
+  using AssemblerAllocator =
+      llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, /*SlabSize=*/32 * 1024>;
+  AssemblerAllocator Allocator;
+
   /// FunctionName and IsInternal are transferred from the original Cfg object,
   /// since the Cfg object may be deleted by the time the assembler buffer is
   /// emitted.
   IceString FunctionName = "";
   bool IsInternal = false;
   /// Preliminary indicates whether a preliminary pass is being made for
   /// calculating bundle padding (Preliminary=true), versus the final pass where
   /// all changes to label bindings, label links, and relocation fixups are
   /// fully committed (Preliminary=false).
   bool Preliminary = false;
 
   /// Installs a created fixup, after it has been allocated.
   void installFixup(AssemblerFixup *F) { Buffer.installFixup(F); }
 
 protected:
   // Buffer's constructor uses the Allocator, so it needs to appear after it.
   // TODO(jpp): dependencies on construction order are a nice way of shooting
   // yourself in the foot. Fix this.
   AssemblerBuffer Buffer;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEASSEMBLER_H_