Generate a custom OSR entrypoint for OSR compiles on all platforms, and transition to optimized cod…

src/x64/builtins-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1400 matching lines @@
   __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
 
   // Pass the function to optimize as the argument to the on-stack
   // replacement runtime function.
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
     __ push(rax);
     __ CallRuntime(Runtime::kCompileForOnStackReplacement, 1);
   }
 
-  // If the result was -1 it means that we couldn't optimize the
-  // function. Just return and continue in the unoptimized version.
   Label skip;
-  __ SmiCompare(rax, Smi::FromInt(-1));
+  // If the code object is null, just return to the unoptimized code.
+  __ cmpq(rax, Immediate(0));
   __ j(not_equal, &skip, Label::kNear);
   __ ret(0);
 
   __ bind(&skip);
-  // Untag the AST id and push it on the stack.
-  __ SmiToInteger32(rax, rax);
-  __ push(rax);
 
-  // Generate the code for doing the frame-to-frame translation using
-  // the deoptimizer infrastructure.
-  Deoptimizer::EntryGenerator generator(masm, Deoptimizer::OSR);
-  generator.Generate();
+  // Load deoptimization data from the code object.
+  __ movq(rbx, Operand(rax, Code::kDeoptimizationDataOffset - kHeapObjectTag));
+
+  // Load the OSR entrypoint offset from the deoptimization data.
+  __ SmiToInteger32(rbx, Operand(rbx, FixedArray::OffsetOfElementAt(
+      DeoptimizationInputData::kOsrPcOffsetIndex) - kHeapObjectTag));
+
+  // Compute the target address = code_obj + header_size + osr_offset
+  __ lea(rax, Operand(rax, rbx, times_1, Code::kHeaderSize - kHeapObjectTag));
+
+  // Overwrite the return address on the stack.
+  __ movq(Operand(rsp, 0), rax);
+
+  // And "return" to the OSR entry point of the function.
+  __ ret(0);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64