Synchronize Android relocation packer source with AOSP.

third_party/android_platform/bionic/tools/relocation_packer/src/packer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "packer.h"
 
 #include <vector>
 
 #include "debug.h"
 #include "delta_encoder.h"
 #include "elf_traits.h"
-#include "leb128.h"
 #include "sleb128.h"
 
 namespace relocation_packer {
 
 // Pack relocations into a group encoded packed representation.
 template <typename ELF>
 void RelocationPacker<ELF>::PackRelocations(const std::vector<typename ELF::Rela>& relocations,
                                             std::vector<uint8_t>* packed) {
   // Run-length encode.
   std::vector<typename ELF::Addr> packed_words;
   RelocationDeltaCodec<ELF> codec;
   codec.Encode(relocations, &packed_words);
 
   // If insufficient data do nothing.
   if (packed_words.empty())
     return;
 
   Sleb128Encoder<typename ELF::Addr> sleb128_encoder;
-  Leb128Encoder<typename ELF::Addr> leb128_encoder;
 
-  std::vector<uint8_t> leb128_packed;
   std::vector<uint8_t> sleb128_packed;
 
-  leb128_encoder.EnqueueAll(packed_words);
-  leb128_encoder.GetEncoding(&leb128_packed);
-
   sleb128_encoder.EnqueueAll(packed_words);
   sleb128_encoder.GetEncoding(&sleb128_packed);
 
-  // TODO (simonb): Estimate savings on current android system image and consider using
-  // one encoder for all packed relocations to reduce complexity.
-  if (leb128_packed.size() <= sleb128_packed.size()) {
-    packed->push_back('A');
-    packed->push_back('P');
-    packed->push_back('U');
-    packed->push_back('2');
-    packed->insert(packed->end(), leb128_packed.begin(), leb128_packed.end());
-  } else {
-    packed->push_back('A');
-    packed->push_back('P');
-    packed->push_back('S');
-    packed->push_back('2');
-    packed->insert(packed->end(), sleb128_packed.begin(), sleb128_packed.end());
-  }
+  packed->push_back('A');
+  packed->push_back('P');
+  packed->push_back('S');
+  packed->push_back('2');
+  packed->insert(packed->end(), sleb128_packed.begin(), sleb128_packed.end());
 }
 
 // Unpack relative relocations from a run-length encoded packed
 // representation.
 template <typename ELF>
 void RelocationPacker<ELF>::UnpackRelocations(
     const std::vector<uint8_t>& packed,
     std::vector<typename ELF::Rela>* relocations) {
 
   std::vector<typename ELF::Addr> packed_words;
   CHECK(packed.size() > 4 &&
         packed[0] == 'A' &&
         packed[1] == 'P' &&
-        (packed[2] == 'U' || packed[2] == 'S') &&
+        packed[2] == 'S' &&
         packed[3] == '2');
 
-  if (packed[2] == 'U') {
-    Leb128Decoder<typename ELF::Addr> decoder(packed, 4);
-    decoder.DequeueAll(&packed_words);
-  } else {
-    Sleb128Decoder<typename ELF::Addr> decoder(packed, 4);
-    decoder.DequeueAll(&packed_words);
-  }
+  Sleb128Decoder<typename ELF::Addr> decoder(packed, 4);
+  decoder.DequeueAll(&packed_words);
 
   RelocationDeltaCodec<ELF> codec;
   codec.Decode(packed_words, relocations);
 }
 
 template class RelocationPacker<ELF32_traits>;
 template class RelocationPacker<ELF64_traits>;
 
 }  // namespace relocation_packer