diff --git a/lldb/include/lldb/Target/Platform.h b/lldb/include/lldb/Target/Platform.h --- a/lldb/include/lldb/Target/Platform.h +++ b/lldb/include/lldb/Target/Platform.h @@ -720,6 +720,24 @@ /// A list of symbol names. The list may be empty. virtual const std::vector &GetTrapHandlerSymbolNames(); + /// Try to get a specific unwind plan for a named trap handler. + /// The default is not to have specific unwind plans for trap handlers. + /// + /// \param[in] machine + /// The architecture of the current target. + /// + /// \param[in] name + /// Name of the trap handler function. + /// + /// \return + /// A specific unwind plan for that trap handler, or an empty + /// shared pointer. The latter means there is no specific plan, + /// unwind as normal. + virtual lldb::UnwindPlanSP + GetTrapHandlerUnwindPlan(llvm::Triple::ArchType machine, ConstString name) { + return {}; + } + /// Find a support executable that may not live within in the standard /// locations related to LLDB. /// diff --git a/lldb/source/Plugins/Platform/Linux/PlatformLinux.h b/lldb/source/Plugins/Platform/Linux/PlatformLinux.h --- a/lldb/source/Plugins/Platform/Linux/PlatformLinux.h +++ b/lldb/source/Plugins/Platform/Linux/PlatformLinux.h @@ -50,6 +50,9 @@ void CalculateTrapHandlerSymbolNames() override; + lldb::UnwindPlanSP GetTrapHandlerUnwindPlan(llvm::Triple::ArchType machine, + ConstString name) override; + MmapArgList GetMmapArgumentList(const ArchSpec &arch, lldb::addr_t addr, lldb::addr_t length, unsigned prot, unsigned flags, lldb::addr_t fd, diff --git a/lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp b/lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp --- a/lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp +++ b/lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp @@ -14,9 +14,11 @@ #include #endif +#include "Utility/ARM64_DWARF_Registers.h" #include "lldb/Core/Debugger.h" #include "lldb/Core/PluginManager.h" #include "lldb/Host/HostInfo.h" +#include "lldb/Symbol/UnwindPlan.h" #include "lldb/Target/Process.h" #include "lldb/Target/Target.h" #include "lldb/Utility/FileSpec.h" @@ -251,6 +253,61 @@ m_trap_handlers.push_back(ConstString("__restore_rt")); } +static lldb::UnwindPlanSP GetAArch64TrapHanlderUnwindPlan(ConstString name) { + UnwindPlanSP unwind_plan_sp; + if (name != "__kernel_rt_sigreturn") + return unwind_plan_sp; + + UnwindPlan::RowSP row = std::make_shared(); + row->SetOffset(0); + + // In the signal trampoline frame, sp points to an rt_sigframe[1], which is: + // - 128-byte siginfo struct + // - ucontext struct: + // - 8-byte long (uc_flags) + // - 8-byte pointer (uc_link) + // - 24-byte stack_t + // - 128-byte signal set + // - 8 bytes of padding because sigcontext has 16-byte alignment + // - sigcontext/mcontext_t + // [1] + // https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/signal.c + int32_t offset = 128 + 8 + 8 + 24 + 128 + 8; + // Then sigcontext[2] is: + // - 8 byte fault address + // - 31 8 byte registers + // - 8 byte sp + // - 8 byte pc + // [2] + // https://github.com/torvalds/linux/blob/master/arch/arm64/include/uapi/asm/sigcontext.h + offset += 8 + (31 * 8); + row->GetCFAValue().SetIsRegisterPlusOffset(arm64_dwarf::sp, offset); + row->SetRegisterLocationToAtCFAPlusOffset(arm64_dwarf::fp, 0, false); + row->SetRegisterLocationToAtCFAPlusOffset(arm64_dwarf::pc, 8, false); + + unwind_plan_sp = std::make_shared(eRegisterKindGeneric); + unwind_plan_sp->AppendRow(row); + unwind_plan_sp->SetSourceName("AArch64 Linux sigcontext"); + unwind_plan_sp->SetSourcedFromCompiler(eLazyBoolYes); + // Because sp is the same throughout the function + unwind_plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolYes); + unwind_plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolYes); + unwind_plan_sp->SetRegisterKind(eRegisterKindDWARF); + + return unwind_plan_sp; +} + +lldb::UnwindPlanSP +PlatformLinux::GetTrapHandlerUnwindPlan(llvm::Triple::ArchType machine, + ConstString name) { + if ((machine == llvm::Triple::ArchType::aarch64 || + machine == llvm::Triple::ArchType::aarch64_be || + machine == llvm::Triple::ArchType::aarch64_32)) + return GetAArch64TrapHanlderUnwindPlan(name); + + return {}; +} + MmapArgList PlatformLinux::GetMmapArgumentList(const ArchSpec &arch, addr_t addr, addr_t length, unsigned prot, unsigned flags, diff --git a/lldb/source/Target/RegisterContextUnwind.cpp b/lldb/source/Target/RegisterContextUnwind.cpp --- a/lldb/source/Target/RegisterContextUnwind.cpp +++ b/lldb/source/Target/RegisterContextUnwind.cpp @@ -900,6 +900,17 @@ // unwind out of sigtramp. if (m_frame_type == eTrapHandlerFrame && process) { m_fast_unwind_plan_sp.reset(); + + if (m_sym_ctx_valid) { + lldb::PlatformSP platform = process->GetTarget().GetPlatform(); + unwind_plan_sp = platform->GetTrapHandlerUnwindPlan( + process->GetTarget().GetArchitecture().GetMachine(), + GetSymbolOrFunctionName(m_sym_ctx)); + + if (unwind_plan_sp) + return unwind_plan_sp; + } + unwind_plan_sp = func_unwinders_sp->GetEHFrameUnwindPlan(process->GetTarget()); if (!unwind_plan_sp) diff --git a/lldb/test/API/functionalities/signal/handle-abrt/TestHandleAbort.py b/lldb/test/API/functionalities/signal/handle-abrt/TestHandleAbort.py --- a/lldb/test/API/functionalities/signal/handle-abrt/TestHandleAbort.py +++ b/lldb/test/API/functionalities/signal/handle-abrt/TestHandleAbort.py @@ -16,8 +16,6 @@ NO_DEBUG_INFO_TESTCASE = True @skipIfWindows # signals do not exist on Windows - # Fails on Ubuntu Focal - @skipIf(archs=["aarch64"], oslist=["linux"]) @expectedFailureNetBSD def test_inferior_handle_sigabrt(self): """Inferior calls abort() and handles the resultant SIGABRT. @@ -47,6 +45,9 @@ self.assertEqual(thread.GetStopReasonDataAtIndex(0), signo, "The stop signal should be SIGABRT") + # Save the backtrace frames to compare to the handler backtrace later. + signal_frames = thread.get_thread_frames() + # Continue to breakpoint in abort handler bkpt = target.FindBreakpointByID( lldbutil.run_break_set_by_source_regexp(self, "Set a breakpoint here")) @@ -58,13 +59,21 @@ frame = thread.GetFrameAtIndex(0) self.assertEqual(frame.GetDisplayFunctionName(), "handler", "Unexpected break?") + handler_frames = thread.get_thread_frames() + # Expect that unwinding should find 'abort_caller' - foundFoo = False - for frame in thread: + found_caller = False + for frame in handler_frames: if frame.GetDisplayFunctionName() == "abort_caller": - foundFoo = True + found_caller = True + break + + self.assertTrue(found_caller, "Unwinding did not find func that called abort") - self.assertTrue(foundFoo, "Unwinding did not find func that called abort") + # Check that frames present in both backtraces have the same addresses. + # The signal handler backtrace has extra frames at the start. + self.assertEqual(signal_frames, handler_frames[-len(signal_frames):], + "Common frames for signal and signal handler backtrace do not match") # Continue until we exit. process.Continue()