diff options
Diffstat (limited to 'lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp')
| -rw-r--r-- | lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp | 254 |
1 files changed, 238 insertions, 16 deletions
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp index af630eee7265..653e007c7b5f 100644 --- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp +++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp @@ -1,4 +1,4 @@ -//===-- AppleThreadPlanStepThroughObjCTrampoline.cpp +//===-- AppleThreadPlanStepThroughObjCTrampoline.cpp-----------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. @@ -29,7 +29,7 @@ using namespace lldb_private; // ThreadPlanStepThroughObjCTrampoline constructor AppleThreadPlanStepThroughObjCTrampoline:: AppleThreadPlanStepThroughObjCTrampoline( - Thread &thread, AppleObjCTrampolineHandler *trampoline_handler, + Thread &thread, AppleObjCTrampolineHandler &trampoline_handler, ValueList &input_values, lldb::addr_t isa_addr, lldb::addr_t sel_addr, bool stop_others) : ThreadPlan(ThreadPlan::eKindGeneric, @@ -48,31 +48,30 @@ void AppleThreadPlanStepThroughObjCTrampoline::DidPush() { // Setting up the memory space for the called function text might require // allocations, i.e. a nested function call. This needs to be done as a // PreResumeAction. - m_thread.GetProcess()->AddPreResumeAction(PreResumeInitializeFunctionCaller, - (void *)this); + m_process.AddPreResumeAction(PreResumeInitializeFunctionCaller, (void *)this); } bool AppleThreadPlanStepThroughObjCTrampoline::InitializeFunctionCaller() { if (!m_func_sp) { DiagnosticManager diagnostics; m_args_addr = - m_trampoline_handler->SetupDispatchFunction(m_thread, m_input_values); + m_trampoline_handler.SetupDispatchFunction(GetThread(), m_input_values); if (m_args_addr == LLDB_INVALID_ADDRESS) { return false; } m_impl_function = - m_trampoline_handler->GetLookupImplementationFunctionCaller(); + m_trampoline_handler.GetLookupImplementationFunctionCaller(); ExecutionContext exc_ctx; EvaluateExpressionOptions options; options.SetUnwindOnError(true); options.SetIgnoreBreakpoints(true); options.SetStopOthers(m_stop_others); - m_thread.CalculateExecutionContext(exc_ctx); + GetThread().CalculateExecutionContext(exc_ctx); m_func_sp = m_impl_function->GetThreadPlanToCallFunction( exc_ctx, m_args_addr, options, diagnostics); m_func_sp->SetOkayToDiscard(true); - m_thread.QueueThreadPlan(m_func_sp, false); + PushPlan(m_func_sp); } return true; } @@ -132,7 +131,7 @@ bool AppleThreadPlanStepThroughObjCTrampoline::ShouldStop(Event *event_ptr) { if (!m_run_to_sp) { Value target_addr_value; ExecutionContext exc_ctx; - m_thread.CalculateExecutionContext(exc_ctx); + GetThread().CalculateExecutionContext(exc_ctx); m_impl_function->FetchFunctionResults(exc_ctx, m_args_addr, target_addr_value); m_impl_function->DeallocateFunctionResults(exc_ctx, m_args_addr); @@ -145,19 +144,19 @@ bool AppleThreadPlanStepThroughObjCTrampoline::ShouldStop(Event *event_ptr) { SetPlanComplete(); return true; } - if (m_trampoline_handler->AddrIsMsgForward(target_addr)) { + if (m_trampoline_handler.AddrIsMsgForward(target_addr)) { LLDB_LOGF(log, "Implementation lookup returned msgForward function: 0x%" PRIx64 ", stopping.", target_addr); - SymbolContext sc = m_thread.GetStackFrameAtIndex(0)->GetSymbolContext( + SymbolContext sc = GetThread().GetStackFrameAtIndex(0)->GetSymbolContext( eSymbolContextEverything); Status status; const bool abort_other_plans = false; const bool first_insn = true; const uint32_t frame_idx = 0; - m_run_to_sp = m_thread.QueueThreadPlanForStepOutNoShouldStop( + m_run_to_sp = GetThread().QueueThreadPlanForStepOutNoShouldStop( abort_other_plans, &sc, first_insn, m_stop_others, eVoteNoOpinion, eVoteNoOpinion, frame_idx, status); if (m_run_to_sp && status.Success()) @@ -180,11 +179,10 @@ bool AppleThreadPlanStepThroughObjCTrampoline::ShouldStop(Event *event_ptr) { // Extract the target address from the value: m_run_to_sp = std::make_shared<ThreadPlanRunToAddress>( - m_thread, target_so_addr, m_stop_others); - m_thread.QueueThreadPlan(m_run_to_sp, false); - m_run_to_sp->SetPrivate(true); + GetThread(), target_so_addr, m_stop_others); + PushPlan(m_run_to_sp); return false; - } else if (m_thread.IsThreadPlanDone(m_run_to_sp.get())) { + } else if (GetThread().IsThreadPlanDone(m_run_to_sp.get())) { // Third stage, work the run to target plan. SetPlanComplete(); return true; @@ -199,3 +197,227 @@ bool AppleThreadPlanStepThroughObjCTrampoline::MischiefManaged() { } bool AppleThreadPlanStepThroughObjCTrampoline::WillStop() { return true; } + +// Objective-C uses optimized dispatch functions for some common and seldom +// overridden methods. For instance +// [object respondsToSelector:]; +// will get compiled to: +// objc_opt_respondsToSelector(object); +// This checks whether the selector has been overridden, directly calling the +// implementation if it hasn't and calling objc_msgSend if it has. +// +// We need to get into the overridden implementation. We'll do that by +// setting a breakpoint on objc_msgSend, and doing a "step out". If we stop +// at objc_msgSend, we can step through to the target of the send, and see if +// that's a place we want to stop. +// +// A couple of complexities. The checking code might call some other method, +// so we might see objc_msgSend more than once. Also, these optimized dispatch +// functions might dispatch more than one message at a time (e.g. alloc followed +// by init.) So we can't give up at the first objc_msgSend. +// That means among other things that we have to handle the "ShouldStopHere" - +// since we can't just return control to the plan that's controlling us on the +// first step. + +AppleThreadPlanStepThroughDirectDispatch :: + AppleThreadPlanStepThroughDirectDispatch( + Thread &thread, AppleObjCTrampolineHandler &handler, + llvm::StringRef dispatch_func_name, bool stop_others, + LazyBool step_in_avoids_code_without_debug_info) + : ThreadPlanStepOut(thread, nullptr, true /* first instruction */, + stop_others, eVoteNoOpinion, eVoteNoOpinion, + 0 /* Step out of zeroth frame */, + eLazyBoolNo /* Our parent plan will decide this + when we are done */ + , + true /* Run to branch for inline step out */, + false /* Don't gather the return value */), + m_trampoline_handler(handler), + m_dispatch_func_name(std::string(dispatch_func_name)), + m_at_msg_send(false), m_stop_others(stop_others) { + // Set breakpoints on the dispatch functions: + auto bkpt_callback = [&] (lldb::addr_t addr, + const AppleObjCTrampolineHandler + ::DispatchFunction &dispatch) { + m_msgSend_bkpts.push_back(GetTarget().CreateBreakpoint(addr, + true /* internal */, + false /* hard */)); + m_msgSend_bkpts.back()->SetThreadID(GetThread().GetID()); + }; + handler.ForEachDispatchFunction(bkpt_callback); + + // We'll set the step-out plan in the DidPush so it gets queued in the right + // order. + + bool avoid_nodebug = true; + + switch (step_in_avoids_code_without_debug_info) { + case eLazyBoolYes: + avoid_nodebug = true; + break; + case eLazyBoolNo: + avoid_nodebug = false; + break; + case eLazyBoolCalculate: + avoid_nodebug = GetThread().GetStepInAvoidsNoDebug(); + break; + } + if (avoid_nodebug) + GetFlags().Set(ThreadPlanShouldStopHere::eStepInAvoidNoDebug); + else + GetFlags().Clear(ThreadPlanShouldStopHere::eStepInAvoidNoDebug); + // We only care about step in. Our parent plan will figure out what to + // do when we've stepped out again. + GetFlags().Clear(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug); +} + +AppleThreadPlanStepThroughDirectDispatch:: + ~AppleThreadPlanStepThroughDirectDispatch() { + for (BreakpointSP bkpt_sp : m_msgSend_bkpts) { + GetTarget().RemoveBreakpointByID(bkpt_sp->GetID()); + } +} + +void AppleThreadPlanStepThroughDirectDispatch::GetDescription( + Stream *s, lldb::DescriptionLevel level) { + switch (level) { + case lldb::eDescriptionLevelBrief: + s->PutCString("Step through ObjC direct dispatch function."); + break; + default: + s->Printf("Step through ObjC direct dispatch '%s' using breakpoints: ", + m_dispatch_func_name.c_str()); + bool first = true; + for (auto bkpt_sp : m_msgSend_bkpts) { + if (!first) { + s->PutCString(", "); + } + first = false; + s->Printf("%d", bkpt_sp->GetID()); + } + (*s) << "."; + break; + } +} + +bool +AppleThreadPlanStepThroughDirectDispatch::DoPlanExplainsStop(Event *event_ptr) { + if (ThreadPlanStepOut::DoPlanExplainsStop(event_ptr)) + return true; + + StopInfoSP stop_info_sp = GetPrivateStopInfo(); + + // Check if the breakpoint is one of ours msgSend dispatch breakpoints. + + StopReason stop_reason = eStopReasonNone; + if (stop_info_sp) + stop_reason = stop_info_sp->GetStopReason(); + + // See if this is one of our msgSend breakpoints: + if (stop_reason == eStopReasonBreakpoint) { + ProcessSP process_sp = GetThread().GetProcess(); + uint64_t break_site_id = stop_info_sp->GetValue(); + BreakpointSiteSP site_sp + = process_sp->GetBreakpointSiteList().FindByID(break_site_id); + // Some other plan might have deleted the site's last owner before this + // got to us. In which case, it wasn't our breakpoint... + if (!site_sp) + return false; + + for (BreakpointSP break_sp : m_msgSend_bkpts) { + if (site_sp->IsBreakpointAtThisSite(break_sp->GetID())) { + // If we aren't the only one with a breakpoint on this site, then we + // should just stop and return control to the user. + if (site_sp->GetNumberOfOwners() > 1) { + SetPlanComplete(true); + return false; + } + m_at_msg_send = true; + return true; + } + } + } + + // We're done here. If one of our sub-plans explained the stop, they + // would have already answered true to PlanExplainsStop, and if they were + // done, we'll get called to figure out what to do in ShouldStop... + return false; +} + +bool AppleThreadPlanStepThroughDirectDispatch + ::DoWillResume(lldb::StateType resume_state, bool current_plan) { + ThreadPlanStepOut::DoWillResume(resume_state, current_plan); + m_at_msg_send = false; + return true; +} + +bool AppleThreadPlanStepThroughDirectDispatch::ShouldStop(Event *event_ptr) { + // If step out plan finished, that means we didn't find our way into a method + // implementation. Either we went directly to the default implementation, + // of the overridden implementation didn't have debug info. + // So we should mark ourselves as done. + const bool step_out_should_stop = ThreadPlanStepOut::ShouldStop(event_ptr); + if (step_out_should_stop) { + SetPlanComplete(true); + return true; + } + + // If we have a step through plan, then w're in the process of getting + // through an ObjC msgSend. If we arrived at the target function, then + // check whether we have debug info, and if we do, stop. + Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); + + if (m_objc_step_through_sp && m_objc_step_through_sp->IsPlanComplete()) { + // If the plan failed for some reason, we should probably just let the + // step over plan get us out of here... We don't need to do anything about + // the step through plan, it is done and will get popped when we continue. + if (!m_objc_step_through_sp->PlanSucceeded()) { + LLDB_LOGF(log, "ObjC Step through plan failed. Stepping out."); + } + Status error; + if (InvokeShouldStopHereCallback(eFrameCompareYounger, error)) { + SetPlanComplete(true); + return true; + } + // If we didn't want to stop at this msgSend, there might be another so + // we should just continue on with the step out and see if our breakpoint + // triggers again. + m_objc_step_through_sp.reset(); + for (BreakpointSP bkpt_sp : m_msgSend_bkpts) { + bkpt_sp->SetEnabled(true); + } + return false; + } + + // If we hit an msgSend breakpoint, then we should queue the step through + // plan: + + if (m_at_msg_send) { + LanguageRuntime *objc_runtime + = GetThread().GetProcess()->GetLanguageRuntime(eLanguageTypeObjC); + // There's no way we could have gotten here without an ObjC language + // runtime. + assert(objc_runtime); + m_objc_step_through_sp + = objc_runtime->GetStepThroughTrampolinePlan(GetThread(), m_stop_others); + // If we failed to find the target for this dispatch, just keep going and + // let the step out complete. + if (!m_objc_step_through_sp) { + LLDB_LOG(log, "Couldn't find target for message dispatch, continuing."); + return false; + } + // Otherwise push the step through plan and continue. + GetThread().QueueThreadPlan(m_objc_step_through_sp, false); + for (BreakpointSP bkpt_sp : m_msgSend_bkpts) { + bkpt_sp->SetEnabled(false); + } + return false; + } + return true; +} + +bool AppleThreadPlanStepThroughDirectDispatch::MischiefManaged() { + if (IsPlanComplete()) + return true; + return ThreadPlanStepOut::MischiefManaged(); +} |