Handle branch relative to pc in ARM integrated assembler.

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 29 matching lines @@
 
 public:
   Label() = default;
   ~Label() = default;
 
   virtual void finalCheck() const {
     // Assert if label is being destroyed with unresolved branches pending.
     assert(!isLinked());
   }
 
+  /// Returns the encoded position stored in the label.
+  intptr_t getEncodedPosition() const { return Position; }
+
   /// Returns the position for bound labels (branches that come after this are
   /// considered backward branches). Cannot be used for unused or linked labels.
   intptr_t getPosition() const {
     assert(isBound());
     return -Position - kWordSize;
   }
 
   /// Returns the position of an earlier branch instruction that was linked to
   /// this label (branches that use this are considered forward branches). The
   /// linked instructions form a linked list, of sorts, using the instruction's
@@ skipping 10 matching lines @@
   bool isLinked() const { return Position > 0; }
 
   virtual bool isUnused() const { return Position == 0; }
 
   void bindTo(intptr_t position) {
     assert(!isBound());
     Position = -position - kWordSize;
     assert(isBound());
   }
 
-protected:
   void linkTo(intptr_t position) {
     assert(!isBound());
     Position = position + kWordSize;
     assert(isLinked());
   }
 
+protected:
   intptr_t Position = 0;
 
   // TODO(jvoung): why are labels offset by this?
   static constexpr uint32_t kWordSize = sizeof(uint32_t);
 };
 
 /// Assembler buffers are used to emit binary code. They grow on demand.
 class AssemblerBuffer {
   AssemblerBuffer(const AssemblerBuffer &) = delete;
   AssemblerBuffer &operator=(const AssemblerBuffer &) = delete;
@@ skipping 244 matching lines @@
   GlobalContext *Ctx;
   // 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_