ART: Avoid expensive class lookup in compiler driver

When we are not compiling multidex, avoid an expensive by-descriptor
lookup for classes when deciding whether to skip compilation.

Bug: 17072698

(cherry picked from commit d84f916d35bb0dc74d7daa075b883e5ee1ce1109)

Change-Id: I19bcb2a2928207fcae0badd466cdc52945bd37c4

1 files changed, 7 insertions, 1 deletions

diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index 645fc1c155..1dd98fefcf 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -1524,7 +1524,13 @@ static bool SkipClass(ClassLinker* class_linker, jobject class_loader, const Dex
     return true;
   }
 
-  return SkipClassCheckClassPath(descriptor, dex_file, dex_files);
+  if (dex_files.size() > 1) {
+    // Multi-dex compilation, only take first class.
+    return SkipClassCheckClassPath(descriptor, dex_file, dex_files);
+  } else {
+    // Single dex, take everything.
+    return false;
+  }
 }
 
 // A fast version of SkipClass above if the class pointer is available