Handle Changes in OAT Files for Android 8.1 (OAT 131)

- The OAT Header has a new field containing the offset to the
  entries for the DEX files.
    - The change was made in OAT 127.
    - All offsets in the header had to be adjusted to account
      for this new field.
    - The offset to the entries for the DEX files also had to
      be adjusted to use this field as they are no longer
      right after the key value store.
- The format of the DEX entries also changed in OAT 127 and
  again in OAT 131.
    - The field containing the offset to the method bss
      mapping was added in OAT 127.
    - The field containing the offset to the dex sections
      layout was added in OAT 131 right before the method
      bss mapping offset.

dexlib2/OatVersions.txt

@@ -88,3 +88,29 @@ bfb80d25eaeb7a604d5dd25a370e3869e96a33ab - 114
 f44d36c8423f81cbb5e9f55d8813e26ffa1a7f3b - 115 (115 again. heck if I know what's going on)
 cbcedbf9382bc773713cd3552ed96f417bf1daeb - 116
 051071718085ce807a2e7c55278a8d723e238e86 - 116
+1595815c2a914a78df7dfb6f0082f47d4e82bb36 - 117
+f4f2daafb38c9c07ea74044a0fb89a2a19288b7a - 118
+6bc7774426cc0b6bbab5566fa62b3c509455e583 - 119
+88d329a698ba186aeb1f1ef8794355512ada84a9 - 120
+612ff540cd3329935351f05923358cf29b9c9b44 - 121
+c83dd7bfde2171c879efb92a31a363505385ffb9 - 122
+eee1c0ec2b08a6be642b329dc2fe885391127da3 - 123
+f977691961b5a49a074a535fcb29a5ad4a318974 - 124
+2665bc8159698429f20a08f814e63c434910d608 - 124
+88abba2b0cb0151d89e16da3e64025878dc2f142 - 125
+99cdddaf8e5bc6b31d0eb375755ec4071a9fb527 - 125
+c137cb03a90b9fd5a7d0ec7dd9b250db82ca88ef - 126
+0eb882bfc5d260e8014c26adfda11602065aa5d8 - 127
+    - The oat_dex_files_offset field is added to the OatHeader class in art/runtime/oat.h.
+    - The method_bss_mapping field is added to the OatDexFile class in art/runtime/oat_file.h.
+7b0648aa7cb4b7a58e73bf353e031dfe4553d9d7 - 128
+0cb172874481f736c6b7c491dd621166cc25561b - 129
+a308a327884920cbb1e3e62964c4b5a01c29af8c - 130 (changed kMultiDexSeparator from ':' to '!')
+4147fcc43c2ee019a06e55384985e3eaf82dcb8c - 131
+75c5ed6e75f70002db5fa7c609137c04dd2bdf40 - 131
+    - The dex_layout_sections field is added to OatDexFile class in art/runtime/oat_file.h.
+    - They did some kind of rebase or something so this commit is not in the master branch anymore.
+    - Only indication is that they cherry picked some things from this commit for oat 132.
+120aa286ab6adf3e76a31bc61fb4e583e5158d71 - 132
+    - The commit containing cherry picked changes from commit 75c5ed6e.
+    - No other noteable changes to the Oat format.

dexlib2/src/main/java/org/jf/dexlib2/dexbacked/OatFile.java

@@ -245,9 +245,15 @@ public class OatFile extends BaseDexBuffer implements MultiDexContainer<OatDexFi
 
     private class OatHeader {
         private final int headerOffset;
+        private final int keyValueStoreOffset;
 
         public OatHeader(int offset) {
             this.headerOffset = offset;
+            if (getVersion() >= 127) {
+                this.keyValueStoreOffset = 19 * 4;
+            } else {
+                this.keyValueStoreOffset = 18 * 4;
+            }
         }
 
         public boolean isValid() {
@@ -278,7 +284,7 @@ public class OatFile extends BaseDexBuffer implements MultiDexContainer<OatDexFi
             if (getVersion() < MIN_OAT_VERSION) {
                 throw new IllegalStateException("Unsupported oat version");
             }
-            int fieldOffset = 17 * 4;
+            int fieldOffset = keyValueStoreOffset - 4;
             return readSmallUint(headerOffset + fieldOffset);
         }
 
@@ -286,14 +292,14 @@ public class OatFile extends BaseDexBuffer implements MultiDexContainer<OatDexFi
             if (getVersion() < MIN_OAT_VERSION) {
                 throw new IllegalStateException("Unsupported oat version");
             }
-            return 18*4 + getKeyValueStoreSize();
+            return keyValueStoreOffset + getKeyValueStoreSize();
         }
 
         @Nullable
         public String getKeyValue(@Nonnull String key) {
             int size = getKeyValueStoreSize();
 
-            int offset = headerOffset + 18 * 4;
+            int offset = headerOffset + keyValueStoreOffset;
             int endOffset = offset + size;
 
             while (offset < endOffset) {
@@ -324,7 +330,11 @@ public class OatFile extends BaseDexBuffer implements MultiDexContainer<OatDexFi
         }
 
         public int getDexListStart() {
-            return headerOffset + getHeaderSize();
+            if (getVersion() >= 127) {
+                return headerOffset + readSmallUint(headerOffset + (6 * 4));
+            } else {
+                return headerOffset + getHeaderSize();
+            }
         }
     }
 
@@ -598,6 +608,12 @@ public class OatFile extends BaseDexBuffer implements MultiDexContainer<OatDexFi
             if (getOatVersion() >= 73) {
                 offset += 4; // lookup table offset
             }
+            if (getOatVersion() >= 131) {
+                offset += 4; // dex sections layout offset
+            }
+            if (getOatVersion() >= 127) {
+                offset += 4; // method bss mapping offset
+            }
             if (getOatVersion() < 75) {
                 // prior to 75, the class offsets are included here directly
                 int classCount = readSmallUint(dexOffset + HeaderItem.CLASS_COUNT_OFFSET);