diff options
Diffstat (limited to 'lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp')
| -rw-r--r-- | lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp | 71 |
1 files changed, 68 insertions, 3 deletions
diff --git a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp index 730784bb2db..af70858e522 100644 --- a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp +++ b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp @@ -23,6 +23,7 @@ #include "lldb/Target/Thread.h" #include "lldb/Target/Target.h" #include "lldb/Target/UnwindAssembly.h" +#include "lldb/Utility/RegisterNumber.h" using namespace lldb; using namespace lldb_private; @@ -955,7 +956,9 @@ AssemblyParse_x86::augment_unwind_plan_from_call_site (AddressRange& func, Unwin // If we already have one row for this instruction, we can continue. while (row_id < unwind_plan.GetRowCount() && unwind_plan.GetRowAtIndex (row_id)->GetOffset() <= offset) + { row_id++; + } UnwindPlan::RowSP original_row = unwind_plan.GetRowAtIndex (row_id - 1); if (original_row->GetOffset() == offset) { @@ -1262,9 +1265,71 @@ UnwindAssembly_x86::GetNonCallSiteUnwindPlanFromAssembly (AddressRange& func, Th bool UnwindAssembly_x86::AugmentUnwindPlanFromCallSite (AddressRange& func, Thread& thread, UnwindPlan& unwind_plan) { - ExecutionContext exe_ctx (thread.shared_from_this()); - AssemblyParse_x86 asm_parse(exe_ctx, m_cpu, m_arch, func); - return asm_parse.augment_unwind_plan_from_call_site (func, unwind_plan); + bool do_augment_unwindplan = true; + + UnwindPlan::RowSP first_row = unwind_plan.GetRowForFunctionOffset (0); + UnwindPlan::RowSP last_row = unwind_plan.GetRowForFunctionOffset (-1); + + // If the UnwindPlan correctly describes the prologue and the epilogue, then + // we shouldn't do any augmentation (and risk messing up correct unwind instructions) + + // See if the first row (which should be the register state on function entry) + // and the last row (which should be the register state on function exit) match. + + if (first_row != last_row && first_row->GetOffset() != last_row->GetOffset()) + { + RegisterNumber sp_regnum (thread, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP); + + // The first & last row have the same CFA register + // and the same CFA offset value + // and the CFA register is esp/rsp (the stack pointer). + + // We're checking that both of them have an unwind rule like "CFA=esp+4" or CFA+rsp+8". + + if (first_row->GetCFAType() == last_row->GetCFAType() + && first_row->GetCFAType() == UnwindPlan::Row::CFAType::CFAIsRegisterPlusOffset + && first_row->GetCFARegister() == last_row->GetCFARegister() + && first_row->GetCFAOffset() == last_row->GetCFAOffset() + && RegisterNumber (thread, unwind_plan.GetRegisterKind(), first_row->GetCFARegister()) == sp_regnum) + { + RegisterNumber pc_regnum (thread, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC); + + // Get the register locations for eip/rip from the first & last rows. + // Are they both CFA plus an offset? Is it the same offset? + + UnwindPlan::Row::RegisterLocation first_row_pc_loc; + UnwindPlan::Row::RegisterLocation last_row_pc_loc; + if (first_row->GetRegisterInfo (pc_regnum.GetAsKind (unwind_plan.GetRegisterKind()), first_row_pc_loc) + && last_row->GetRegisterInfo (pc_regnum.GetAsKind (unwind_plan.GetRegisterKind()), last_row_pc_loc)) + { + if (first_row_pc_loc.IsAtCFAPlusOffset() + && last_row_pc_loc.IsAtCFAPlusOffset() + && first_row_pc_loc.GetOffset() == last_row_pc_loc.GetOffset()) + { + + // One last sanity check: Is the unwind rule for getting the caller pc value + // "deref the CFA-4" or "deref the CFA-8"? + + // If so, we have an UnwindPlan that already describes the epilogue and we don't need + // to modify it at all. + + if (first_row_pc_loc.GetOffset() == -4 || first_row_pc_loc.GetOffset() == -8) + { + do_augment_unwindplan = false; + } + } + } + } + } + + if (do_augment_unwindplan) + { + ExecutionContext exe_ctx (thread.shared_from_this()); + AssemblyParse_x86 asm_parse(exe_ctx, m_cpu, m_arch, func); + return asm_parse.augment_unwind_plan_from_call_site (func, unwind_plan); + } + + return false; } bool |
