Revert "Revert "ART: Register allocation and runtime support for try/catch""

The original CL triggered b/24084144 which has been fixed
by Ib72e12a018437c404e82f7ad414554c66a4c6f8c.

This reverts commit 659562aaf133c41b8d90ec9216c07646f0f14362.

Change-Id: Id8980436172457d0fcb276349c4405f7c4110a55
diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index 07b79b5..a15a081 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -1115,7 +1115,7 @@
     region_.StoreUnaligned<NumberOfStackMapsType>(kNumberOfStackMapsOffset, number_of_stack_maps);
   }
 
-  // Get the size all the stack maps of this CodeInfo object, in bytes.
+  // Get the size of all the stack maps of this CodeInfo object, in bytes.
   size_t GetStackMapsSize(const StackMapEncoding& encoding) const {
     return encoding.ComputeStackMapSize() * GetNumberOfStackMaps();
   }
@@ -1174,9 +1174,23 @@
     return StackMap();
   }
 
+  // Searches the stack map list backwards because catch stack maps are stored
+  // at the end.
+  StackMap GetCatchStackMapForDexPc(uint32_t dex_pc, const StackMapEncoding& encoding) const {
+    for (size_t i = GetNumberOfStackMaps(); i > 0; --i) {
+      StackMap stack_map = GetStackMapAt(i - 1, encoding);
+      if (stack_map.GetDexPc(encoding) == dex_pc) {
+        return stack_map;
+      }
+    }
+    return StackMap();
+  }
+
   StackMap GetStackMapForNativePcOffset(uint32_t native_pc_offset,
                                         const StackMapEncoding& encoding) const {
-    // TODO: stack maps are sorted by native pc, we can do a binary search.
+    // TODO: Safepoint stack maps are sorted by native_pc_offset but catch stack
+    //       maps are not. If we knew that the method does not have try/catch,
+    //       we could do binary search.
     for (size_t i = 0, e = GetNumberOfStackMaps(); i < e; ++i) {
       StackMap stack_map = GetStackMapAt(i, encoding);
       if (stack_map.GetNativePcOffset(encoding) == native_pc_offset) {