Revert "Lazy deopt without code patching."

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
diff --git a/runtime/vm/flow_graph_compiler_x64.cc b/runtime/vm/flow_graph_compiler_x64.cc
index 021ed5150acd54e53afa3afdc576d767e706f9fa..c56c320e81bec958b8f71a8122ecd0effe722d16 100644
--- a/runtime/vm/flow_graph_compiler_x64.cc
+++ b/runtime/vm/flow_graph_compiler_x64.cc
@@ -1123,6 +1123,19 @@ void FlowGraphCompiler::CompileGraph() {
   __ int3();
   ASSERT(assembler()->constant_pool_allowed());
   GenerateDeferredCode();
+  // Emit function patching code. This will be swapped with the first 13 bytes
+  // at entry point.
+
+  BeginCodeSourceRange();
+  if (is_optimizing() && !FLAG_precompiled_mode) {
+    // Leave enough space for patching in case of lazy deoptimization.
+    __ nop(ShortCallPattern::pattern_length_in_bytes());
+    lazy_deopt_return_pc_offset_ = assembler()->CodeSize();
+    __ Jmp(*StubCode::DeoptimizeLazyFromReturn_entry(), PP);
+    lazy_deopt_throw_pc_offset_ = assembler()->CodeSize();
+    __ Jmp(*StubCode::DeoptimizeLazyFromThrow_entry(), PP);
+  }
+  EndCodeSourceRange(TokenPosition::kDartCodeEpilogue);
 }