Delta-encoding of mapping tables.

Both PC offsets and dalvik offsets are delta-encoded. Since
PC offsets are increasing, the deltas are then compressed as
unsigned LEB128. Dalvik offsets are not monotonic, so their
deltas are compressed as signed LEB128.

This reduces the size of the mapping tables by about 30%
on average, 25% from the PC offset and 5% from the dalvik
offset delta encoding.

Bug: 9437697
Change-Id: I600ab9c22dec178088d4947a811cca3bc8bd4cf4

1 files changed, 10 insertions, 10 deletions

diff --git a/runtime/exception_test.cc b/runtime/exception_test.cc
index e9a6e4fa49..8f542d80ac 100644
--- a/runtime/exception_test.cc
+++ b/runtime/exception_test.cc
@@ -54,17 +54,17 @@ class ExceptionTest : public CommonTest {
       fake_code_.push_back(0x70 | i);
     }
 
-    fake_mapping_data_.PushBack(4);  // first element is count
-    fake_mapping_data_.PushBack(4);  // total (non-length) elements
-    fake_mapping_data_.PushBack(2);  // count of pc to dex elements
+    fake_mapping_data_.PushBackUnsigned(4);  // first element is count
+    fake_mapping_data_.PushBackUnsigned(4);  // total (non-length) elements
+    fake_mapping_data_.PushBackUnsigned(2);  // count of pc to dex elements
                                       // ---  pc to dex table
-    fake_mapping_data_.PushBack(3);  // offset 3
-    fake_mapping_data_.PushBack(3);  // maps to dex offset 3
+    fake_mapping_data_.PushBackUnsigned(3 - 0);  // offset 3
+    fake_mapping_data_.PushBackSigned(3 - 0);    // maps to dex offset 3
                                       // ---  dex to pc table
-    fake_mapping_data_.PushBack(3);  // offset 3
-    fake_mapping_data_.PushBack(3);  // maps to dex offset 3
+    fake_mapping_data_.PushBackUnsigned(3 - 0);  // offset 3
+    fake_mapping_data_.PushBackSigned(3 - 0);    // maps to dex offset 3
 
-    fake_vmap_table_data_.PushBack(0);
+    fake_vmap_table_data_.PushBackUnsigned(0);
 
     fake_gc_map_.push_back(0);  // 0 bytes to encode references and native pc offsets.
     fake_gc_map_.push_back(0);
@@ -91,8 +91,8 @@ class ExceptionTest : public CommonTest {
   const DexFile* dex_;
 
   std::vector<uint8_t> fake_code_;
-  UnsignedLeb128EncodingVector fake_mapping_data_;
-  UnsignedLeb128EncodingVector fake_vmap_table_data_;
+  Leb128EncodingVector fake_mapping_data_;
+  Leb128EncodingVector fake_vmap_table_data_;
   std::vector<uint8_t> fake_gc_map_;
 
   mirror::ArtMethod* method_f_;