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

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 480 matching lines @@
     __ popq(RAX);  // Restore result.
   } else if (kind == kLazyDeoptFromThrow) {
     __ popq(RDX);  // Restore stacktrace.
     __ popq(RAX);  // Restore exception.
   }
   __ LeaveStubFrame();
 
   __ popq(RCX);       // Pop return address.
   __ addq(RSP, RBX);  // Remove materialization arguments.
   __ pushq(RCX);      // Push return address.
-  __ ret();
+  // The caller is responsible for emitting the return instruction.
 }
 
 
 // RAX: result, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromReturnStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ pushq(Immediate(0xf1f1f1f1));
+  __ pushq(Immediate(kZapCodeReg));
   // Return address for "call" to deopt stub.
-  __ pushq(Immediate(0xe1e1e1e1));
+  __ pushq(Immediate(kZapReturnAddress));
   __ movq(CODE_REG, Address(THR, Thread::lazy_deopt_from_return_stub_offset()));
   GenerateDeoptimizationSequence(assembler, kLazyDeoptFromReturn);
+  __ ret();
 }
 
 
 // RAX: exception, must be preserved
 // RDX: stacktrace, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromThrowStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ pushq(Immediate(0xf1f1f1f1));
+  __ pushq(Immediate(kZapCodeReg));
   // Return address for "call" to deopt stub.
-  __ pushq(Immediate(0xe1e1e1e1));
+  __ pushq(Immediate(kZapReturnAddress));
   __ 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();
 }
 
 
 static void GenerateDispatcherCode(Assembler* assembler,
                                    Label* call_target_function) {
   __ Comment("NoSuchMethodDispatch");
   // When lazily generated invocation dispatchers are disabled, the
   // miss-handler may return null.
   __ CompareObject(RAX, Object::null_object());
   __ j(NOT_EQUAL, call_target_function);
@@ skipping 1344 matching lines @@
 
   // Load the stacktrace from the current thread.
   Address stacktrace_addr(THR, Thread::active_stacktrace_offset());
   __ movq(kStackTraceObjectReg, stacktrace_addr);
   __ movq(stacktrace_addr, Immediate(0));
 
   __ jmp(CallingConventions::kArg1Reg);  // Jump to continuation point.
 }
 
 
+// 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).
 void StubCode::GenerateOptimizeFunctionStub(Assembler* assembler) {
   __ EnterStubFrame();
   __ pushq(R10);           // Preserve args descriptor.
   __ pushq(Immediate(0));  // Result slot.
   __ pushq(RDI);           // Arg0: function to optimize
   __ CallRuntime(kOptimizeInvokedFunctionRuntimeEntry, 1);
   __ popq(RAX);  // Disard argument.
@@ skipping 350 matching lines @@
 }
 
 
 void StubCode::GenerateFrameAwaitingMaterializationStub(Assembler* assembler) {
   __ int3();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64