Revert "Implement rewind: drop one or more frames from the debugger."

runtime/vm/stub_code_x64.cc

Index: runtime/vm/stub_code_x64.cc
diff --git a/runtime/vm/stub_code_x64.cc b/runtime/vm/stub_code_x64.cc
index 0341f268f80c2de6cae68d9a28c65721deed2864..167154b0879d8c515d929e4a1b98c2cff9935c90 100644
--- a/runtime/vm/stub_code_x64.cc
+++ b/runtime/vm/stub_code_x64.cc
@@ -498,19 +498,18 @@ static void GenerateDeoptimizationSequence(Assembler* assembler,
   __ popq(RCX);       // Pop return address.
   __ addq(RSP, RBX);  // Remove materialization arguments.
   __ pushq(RCX);      // Push return address.
-  // The caller is responsible for emitting the return instruction.
+  __ ret();
 }
 
 
 // RAX: result, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromReturnStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ pushq(Immediate(kZapCodeReg));
+  __ pushq(Immediate(0xf1f1f1f1));
   // Return address for "call" to deopt stub.
-  __ pushq(Immediate(kZapReturnAddress));
+  __ pushq(Immediate(0xe1e1e1e1));
   __ movq(CODE_REG, Address(THR, Thread::lazy_deopt_from_return_stub_offset()));
   GenerateDeoptimizationSequence(assembler, kLazyDeoptFromReturn);
-  __ ret();
 }
 
 
@@ -518,18 +517,16 @@ void StubCode::GenerateDeoptimizeLazyFromReturnStub(Assembler* assembler) {
 // RDX: stacktrace, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromThrowStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ pushq(Immediate(kZapCodeReg));
+  __ pushq(Immediate(0xf1f1f1f1));
   // Return address for "call" to deopt stub.
-  __ pushq(Immediate(kZapReturnAddress));
+  __ pushq(Immediate(0xe1e1e1e1));
   __ movq(CODE_REG, Address(THR, Thread::lazy_deopt_from_throw_stub_offset()));
   GenerateDeoptimizationSequence(assembler, kLazyDeoptFromThrow);
-  __ ret();
 }
 
 
 void StubCode::GenerateDeoptimizeStub(Assembler* assembler) {
   GenerateDeoptimizationSequence(assembler, kEagerDeopt);
-  __ ret();
 }
 
 
@@ -1894,25 +1891,6 @@ void StubCode::GenerateRunExceptionHandlerStub(Assembler* assembler) {
 }
 
 
-// Deoptimize a frame on the call stack before rewinding.
-// The arguments are stored in the Thread object.
-// No result.
-void StubCode::GenerateDeoptForRewindStub(Assembler* assembler) {
-  // Push zap value instead of CODE_REG.
-  __ pushq(Immediate(kZapCodeReg));
-
-  // Push the deopt pc.
-  __ pushq(Address(THR, Thread::resume_pc_offset()));
-  GenerateDeoptimizationSequence(assembler, kEagerDeopt);
-
-  // After we have deoptimized, jump to the correct frame.
-  __ EnterStubFrame();
-  __ CallRuntime(kRewindPostDeoptRuntimeEntry, 0);
-  __ LeaveStubFrame();
-  __ int3();
-}
-
-
 // Calls to the runtime to optimize the given function.
 // RDI: function to be reoptimized.
 // R10: argument descriptor (preserved).