Make fixups reference any constant (allow const float/double pool literals).

src/assembler.h

 //===- subzero/src/assembler.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 33 matching lines @@
 public:
 
   // It would be ideal if the destructor method could be made private,
   // but the g++ compiler complains when this is subclassed.
   virtual ~AssemblerFixup() { llvm_unreachable("~AssemblerFixup used"); }
 
   intptr_t position() const { return position_; }
 
   FixupKind kind() const { return kind_; }
 
-  const ConstantRelocatable *value() const { return value_; }
+  RelocOffsetT offset() const;
+
+  IceString symbol(GlobalContext *Ctx) const;
+
+  void emit(GlobalContext *Ctx) const;
 
 protected:
-  AssemblerFixup(FixupKind Kind, const ConstantRelocatable *Value)
+  AssemblerFixup(FixupKind Kind, const Constant *Value)
       : position_(0), kind_(Kind), value_(Value) {}
 
 private:
   intptr_t position_;
   FixupKind kind_;
-  const ConstantRelocatable *value_;
+  const Constant *value_;
 
   void set_position(intptr_t position) { position_ = position; }
 
   friend class AssemblerBuffer;
 };
 
 // Assembler buffers are used to emit binary code. They grow on demand.
 class AssemblerBuffer {
   AssemblerBuffer(const AssemblerBuffer &) = delete;
   AssemblerBuffer &operator=(const AssemblerBuffer &) = delete;
@@ skipping 149 matching lines @@
   // Mark the current text location as the start of a CFG node
   // (represented by NodeNumber).
   virtual void BindCfgNodeLabel(SizeT NodeNumber) = 0;
 
   // Return a view of all the bytes of code for the current function.
   llvm::StringRef getBufferView() const;
 
   void emitIASBytes(GlobalContext *Ctx) const;
 
 private:
-  ArenaAllocator Allocator;
+  ArenaAllocator<32 * 1024> Allocator;
 
 protected:
   AssemblerBuffer buffer_;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ASSEMBLER_H_