Revert "Revert "JumpToFrame refactor"" + Fix

runtime/vm/stub_code_ia32.cc

Index: runtime/vm/stub_code_ia32.cc
diff --git a/runtime/vm/stub_code_ia32.cc b/runtime/vm/stub_code_ia32.cc
index 1de178a8c7d97d2d5e3fdfadf8d4634a5f18f760..ca70617824bf92fbfc39004256c45e44bdd276ba 100644
--- a/runtime/vm/stub_code_ia32.cc
+++ b/runtime/vm/stub_code_ia32.cc
@@ -1792,21 +1792,15 @@ void StubCode::GenerateGetStackPointerStub(Assembler* assembler) {
 }
 
 
-// Jump to the exception or error handler.
+// Jump to a frame on the call stack.
 // TOS + 0: return address
 // TOS + 1: program_counter
 // TOS + 2: stack_pointer
 // TOS + 3: frame_pointer
-// TOS + 4: exception object
-// TOS + 5: stacktrace object
-// TOS + 6: thread
+// TOS + 4: thread
 // No Result.
-void StubCode::GenerateJumpToExceptionHandlerStub(Assembler* assembler) {
-  ASSERT(kExceptionObjectReg == EAX);
-  ASSERT(kStackTraceObjectReg == EDX);
-  __ movl(THR, Address(ESP, 6 * kWordSize));  // Load target thread.
-  __ movl(kStackTraceObjectReg, Address(ESP, 5 * kWordSize));
-  __ movl(kExceptionObjectReg, Address(ESP, 4 * kWordSize));
+void StubCode::GenerateJumpToFrameStub(Assembler* assembler) {
+  __ movl(THR, Address(ESP, 4 * kWordSize));  // Load target thread.
   __ movl(EBP, Address(ESP, 3 * kWordSize));  // Load target frame_pointer.
   __ movl(EBX, Address(ESP, 1 * kWordSize));  // Load target PC into EBX.
   __ movl(ESP, Address(ESP, 2 * kWordSize));  // Load target stack_pointer.
@@ -1818,6 +1812,29 @@ void StubCode::GenerateJumpToExceptionHandlerStub(Assembler* assembler) {
 }
 
 
+// Run an exception handler.  Execution comes from JumpToFrame stub.
+//
+// The arguments are stored in the Thread object.
+// No result.
+void StubCode::GenerateRunExceptionHandlerStub(Assembler* assembler) {
+  ASSERT(kExceptionObjectReg == EAX);
+  ASSERT(kStackTraceObjectReg == EDX);
+  __ movl(EBX, Address(THR, Thread::resume_pc_offset()));
+
+  // Load the exception from the current thread.
+  Address exception_addr(THR, Thread::active_exception_offset());
+  __ movl(kExceptionObjectReg, exception_addr);
+  __ movl(exception_addr, Immediate(0));
+
+  // Load the stacktrace from the current thread.
+  Address stacktrace_addr(THR, Thread::active_stacktrace_offset());
+  __ movl(kStackTraceObjectReg, stacktrace_addr);
+  __ movl(stacktrace_addr, Immediate(0));
+
+  __ jmp(EBX);  // Jump to continuation point.
+}
+
+
 // Calls to the runtime to optimize the given function.
 // EBX: function to be reoptimized.
 // EDX: argument descriptor (preserved).