Move some isolate state setup from C++ code to JumpToExceptionHandler stub

runtime/vm/exceptions.cc

Index: runtime/vm/exceptions.cc
diff --git a/runtime/vm/exceptions.cc b/runtime/vm/exceptions.cc
index c8808dde56df204ff1622669897626967d14c669..2e95096f379fde2990eb6dd3f79cea7a6c4330bb 100644
--- a/runtime/vm/exceptions.cc
+++ b/runtime/vm/exceptions.cc
@@ -280,12 +280,11 @@ static void JumpToExceptionHandler(Isolate* isolate,
   RawObject* raw_exception = exception_object.raw();
   RawObject* raw_stacktrace = stacktrace_object.raw();
 
-  // The following three operations are part of the 'epilogue' of the
-  // CallToRuntime, CallBootstrapCFunction, and CallNativeCFunction stubs.
-  // In the case of an exception, we skip the epilogues and must set the
-  // correct state here.
-  isolate->set_vm_tag(VMTag::kScriptTagId);
-  isolate->set_top_exit_frame_info(0);
+  // The following operation is part of the 'epilogue' of the CallToRuntime,
+  // CallBootstrapCFunction, and CallNativeCFunction stubs. In the case of an
+  // exception, we skip the epilogues and must set the correct state here.
+  // The other operations performed as part of the 'epilogue' are handled
+  // by the simulator's Longjmp or the JumpToExceptionHandler stub.
   isolate->set_top_context(Context::null());

[siva, 2014/07/14 20:13:11]

Why not move the resetting of the top context also into the
JumpToExceptionHandler code.

[Cutch, 2014/07/14 21:32:07]

I split it this way because we do not have a pool pointer in the jump to
exception stub and we always load the null object from the pool.

 
 #if defined(USING_SIMULATOR)
@@ -298,7 +297,7 @@ static void JumpToExceptionHandler(Isolate* isolate,
   // object (may be raw null) in the kStackTraceObjectReg register.
 
   Simulator::Current()->Longjmp(program_counter, stack_pointer, frame_pointer,
-                                raw_exception, raw_stacktrace);
+                                raw_exception, raw_stacktrace, isolate);
 #else
   // Prepare for unwinding frames by destroying all the stack resources
   // in the previous frames.
@@ -311,7 +310,8 @@ static void JumpToExceptionHandler(Isolate* isolate,
   // Call a stub to set up the exception object in kExceptionObjectReg,
   // to set up the stacktrace object in kStackTraceObjectReg, and to
   // continue execution at the given pc in the given frame.
-  typedef void (*ExcpHandler)(uword, uword, uword, RawObject*, RawObject*);
+  typedef void (*ExcpHandler)(uword, uword, uword, RawObject*, RawObject*,
+                              Isolate*);
   ExcpHandler func = reinterpret_cast<ExcpHandler>(
       StubCode::JumpToExceptionHandlerEntryPoint());
 
@@ -321,7 +321,7 @@ static void JumpToExceptionHandler(Isolate* isolate,
                                 stack_pointer - current_sp);
 
   func(program_counter, stack_pointer, frame_pointer,
-       raw_exception, raw_stacktrace);
+       raw_exception, raw_stacktrace, isolate);
 #endif
   UNREACHABLE();
 }