[turbofan] Add support for SOFT deopts and use that for property access.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index 4ab4a307bbc3a5d2f499dfa1ff527892c0a81535..a56fa13c488eb6f511aef99f4e525e99721e7732 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -64,6 +64,7 @@ class CompilationInfo {
     kDeoptimizationEnabled = 1 << 16,
     kSourcePositionsEnabled = 1 << 17,
     kFirstCompile = 1 << 18,
+    kBailoutOnUninitialized = 1 << 19,
   };
 
   explicit CompilationInfo(ParseInfo* parse_info);
@@ -207,6 +208,12 @@ class CompilationInfo {
 
   bool is_first_compile() const { return GetFlag(kFirstCompile); }
 
+  void MarkAsBailoutOnUninitialized() { SetFlag(kBailoutOnUninitialized); }
+
+  bool is_bailout_on_uninitialized() const {
+    return GetFlag(kBailoutOnUninitialized);
+  }
+
   bool GeneratePreagedPrologue() const {
     // Generate a pre-aged prologue if we are optimizing for size, which
     // will make code flushing more aggressive. Only apply to Code::FUNCTION,