Merge "Revert "Revert "Implement on-stack replacement for arm/arm64/x86/x86_64."""

1 files changed, 29 insertions, 0 deletions

diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index 84185ce49f..97eb805501 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -1195,6 +1195,35 @@ class CodeInfo {
     return StackMap();
   }
 
+  StackMap GetOsrStackMapForDexPc(uint32_t dex_pc, const StackMapEncoding& encoding) const {
+    size_t e = GetNumberOfStackMaps();
+    if (e == 0) {
+      // There cannot be OSR stack map if there is no stack map.
+      return StackMap();
+    }
+    // Walk over all stack maps. If two consecutive stack maps are identical, then we
+    // have found a stack map suitable for OSR.
+    for (size_t i = 0; i < e - 1; ++i) {
+      StackMap stack_map = GetStackMapAt(i, encoding);
+      if (stack_map.GetDexPc(encoding) == dex_pc) {
+        StackMap other = GetStackMapAt(i + 1, encoding);
+        if (other.GetDexPc(encoding) == dex_pc &&
+            other.GetNativePcOffset(encoding) == stack_map.GetNativePcOffset(encoding)) {
+          DCHECK_EQ(other.GetDexRegisterMapOffset(encoding),
+                    stack_map.GetDexRegisterMapOffset(encoding));
+          DCHECK(!stack_map.HasInlineInfo(encoding));
+          if (i < e - 2) {
+            // Make sure there are not three identical stack maps following each other.
+            DCHECK_NE(stack_map.GetNativePcOffset(encoding),
+                      GetStackMapAt(i + 2, encoding).GetNativePcOffset(encoding));
+          }
+          return stack_map;
+        }
+      }
+    }
+    return StackMap();
+  }
+
   StackMap GetStackMapForNativePcOffset(uint32_t native_pc_offset,
                                         const StackMapEncoding& encoding) const {
     // TODO: Safepoint stack maps are sorted by native_pc_offset but catch stack