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

runtime/vm/stub_code_mips.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_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 531 matching lines @@
   if (kind == kLazyDeoptFromReturn) {
     __ Pop(V0);  // Restore result.
   } else if (kind == kLazyDeoptFromThrow) {
     __ Pop(V1);  // Restore stacktrace.
     __ Pop(V0);  // Restore exception.
   }
   __ LeaveStubFrame();
   // Remove materialization arguments.
   __ SmiUntag(T1);
   __ addu(SP, SP, T1);
-  __ Ret();
+  // The caller is responsible for emitting the return instruction.
 }
 
 // V0: result, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromReturnStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ LoadImmediate(TMP, 0xf1f1f1f1);
+  __ LoadImmediate(TMP, kZapCodeReg);
   __ Push(TMP);
   // Return address for "call" to deopt stub.
-  __ LoadImmediate(RA, 0xe1e1e1e1);
+  __ LoadImmediate(RA, kZapReturnAddress);
   __ lw(CODE_REG, Address(THR, Thread::lazy_deopt_from_return_stub_offset()));
   GenerateDeoptimizationSequence(assembler, kLazyDeoptFromReturn);
+  __ Ret();
 }
 
 
 // V0: exception, must be preserved
 // V1: stacktrace, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromThrowStub(Assembler* assembler) {
   // Push zap value instead of CODE_REG for lazy deopt.
-  __ LoadImmediate(TMP, 0xf1f1f1f1);
+  __ LoadImmediate(TMP, kZapCodeReg);
   __ Push(TMP);
   // Return address for "call" to deopt stub.
-  __ LoadImmediate(RA, 0xe1e1e1e1);
+  __ LoadImmediate(RA, kZapReturnAddress);
   __ lw(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.
   __ BranchNotEqual(T0, Object::null_object(), call_target_function);
   __ EnterStubFrame();
@@ skipping 1429 matching lines @@
 
   // Load the stacktrace from the current thread.
   Address stacktrace_addr(THR, Thread::active_stacktrace_offset());
   __ lw(V1, stacktrace_addr);
 
   __ jr(A0);  // Jump to continuation point.
   __ delay_slot()->sw(A2, stacktrace_addr);
 }
 
 
+// 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.
+  __ LoadImmediate(TMP, kZapCodeReg);
+  __ Push(TMP);
+
+  // Load the deopt pc into RA.
+  __ lw(RA, Address(THR, Thread::resume_pc_offset()));
+  GenerateDeoptimizationSequence(assembler, kEagerDeopt);
+
+  // After we have deoptimized, jump to the correct frame.
+  __ EnterStubFrame();
+  __ CallRuntime(kRewindPostDeoptRuntimeEntry, 0);
+  __ LeaveStubFrame();
+  __ break_(0);
+}
+
+
 // Calls to the runtime to optimize the given function.
 // T0: function to be reoptimized.
 // S4: argument descriptor (preserved).
 void StubCode::GenerateOptimizeFunctionStub(Assembler* assembler) {
   __ Comment("OptimizeFunctionStub");
   __ EnterStubFrame();
   __ addiu(SP, SP, Immediate(-3 * kWordSize));
   __ sw(S4, Address(SP, 2 * kWordSize));
   // Setup space on stack for return value.
   __ sw(ZR, Address(SP, 1 * kWordSize));
@@ skipping 357 matching lines @@
 }
 
 
 void StubCode::GenerateFrameAwaitingMaterializationStub(Assembler* assembler) {
   __ break_(0);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS