Ensure we can always enter OSR code

When the the loop header is not the target of a back-edge,
we used to never enter the OSR code even if it's been compiled.

Test: testrunner.py --host --jit -t 570-checker-osr-locals
      (it used to get stuck, you can kill the dalvikvm to check that
      the weirdLoop was OSR-compiled)
Bug: 136743846

Change-Id: Iae55463eff92adccf9adec842e04f8ff6d9d8568

1 files changed, 5 insertions, 0 deletions

diff --git a/compiler/optimizing/block_builder.h b/compiler/optimizing/block_builder.h
index 2c1f034d80..42a3f327e7 100644
--- a/compiler/optimizing/block_builder.h
+++ b/compiler/optimizing/block_builder.h
@@ -59,6 +59,11 @@ class HBasicBlockBuilder : public ValueObject {
   void ConnectBasicBlocks();
   void InsertTryBoundaryBlocks();
 
+  // To ensure branches with negative offsets can always OSR jump to compiled
+  // code, we insert synthesized loops before each block that is the target of a
+  // negative branch.
+  void InsertSynthesizedLoopsForOsr();
+
   // Helper method which decides whether `catch_block` may have live normal
   // predecessors and thus whether a synthetic catch block needs to be created
   // to avoid mixing normal and exceptional predecessors.