Author: labath Date: Wed Jul 13 05:55:24 2016 New Revision: 275260 URL: http://llvm.org/viewvc/llvm-project?rev=275260&view=rev Log: Add "support" for DW_CFA_GNU_args_size to the unwinder
Summary: This adds the knowledge of the DW_CFA_GNU_args_size instruction to the eh_frame parsing code. Right now it is ignored as I am unsure how is it supposed to be handled, but now we are at least able to parse the rest of the FDE containing this instruction. I also add a fix for a bug which was exposed by this instruction. Namely, a mismatched sequence of remember/restore instructions in the input could cause us to pop an empty stack and crash. Now we just log the error and ignore the offending instruction. Reviewers: jasonmolenda Subscribers: lldb-commits Differential Revision: http://reviews.llvm.org/D22266 Modified: lldb/trunk/source/Symbol/DWARFCallFrameInfo.cpp Modified: lldb/trunk/source/Symbol/DWARFCallFrameInfo.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/DWARFCallFrameInfo.cpp?rev=275260&r1=275259&r2=275260&view=diff ============================================================================== --- lldb/trunk/source/Symbol/DWARFCallFrameInfo.cpp (original) +++ lldb/trunk/source/Symbol/DWARFCallFrameInfo.cpp Wed Jul 13 05:55:24 2016 @@ -408,6 +408,7 @@ DWARFCallFrameInfo::GetFDEIndex () bool DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) { + Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND); lldb::offset_t offset = dwarf_offset; lldb::offset_t current_entry = offset; @@ -648,6 +649,15 @@ DWARFCallFrameInfo::FDEToUnwindPlan (dw_ // the stack and place them in the current row. (This operation is // useful for compilers that move epilogue code into the body of a // function.) + if (stack.empty()) + { + if (log) + log->Printf( + "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32 ", startaddr: %" PRIx64 + " encountered DW_CFA_restore_state but state stack is empty. Corrupt unwind info?", + __FUNCTION__, dwarf_offset, startaddr.GetFileAddress()); + break; + } lldb::addr_t offset = row->GetOffset (); row = stack.back (); stack.pop_back (); @@ -655,6 +665,16 @@ DWARFCallFrameInfo::FDEToUnwindPlan (dw_ break; } + case DW_CFA_GNU_args_size: // 0x2e + { + // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 operand + // representing an argument size. This instruction specifies the total of + // the size of the arguments which have been pushed onto the stack. + + // TODO: Figure out how we should handle this. + m_cfi_data.GetULEB128(&offset); + } + case DW_CFA_val_offset : // 0x14 case DW_CFA_val_offset_sf : // 0x15 default: _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
