On Tue, Aug 13, 2013 at 6:22 PM, Michael Sartain <[email protected]> wrote:
> Unwind info does exist for addresses in main(), and all of this works as > expected in x64. > > I'll start debugging where this is failing... > For x86 elf files, the plt_entsize wasn't being rounded to the proper alignment - this was causing the .plt symbols to be incorrect, along with unwind info, etc. This patch fixes that: http://llvm-reviews.chandlerc.com/D1189 The next problem is we're using the x64 register set, but then calling into the i386 ABI. Ie, this call: 246| addr_t pc; 247+> if (!ReadGPRValue (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, pc)) 248| { Winds up here: 1092| ExecutionContext exe_ctx(m_thread.shared_from_this()); 1093| Process *process = exe_ctx.GetProcessPtr(); 1094| if (have_unwindplan_regloc == false) 1095| { 1096| // If a volatile register is being requested, we don't want to forward the next frame's register contents 1097| // up the stack -- the register is not retrievable at this frame. 1098| ABI *abi = process ? process->GetABI().get() : NULL; 1099| if (abi) 1100| { 1101+> const RegisterInfo *reg_info = GetRegisterInfoAtIndex(lldb_regnum); 1102| if (reg_info && abi->RegisterIsVolatile (reg_info)) 1103| { 1104| UnwindLogMsg ("did not supply reg location for %d (%s) because it is volatile", 1105| lldb_regnum, reg_info->name ? reg_info->name : "??"); 1106| return UnwindLLDB::RegisterSearchResult::eRegisterIsVolatile; 1107| } 1108| } Which calls into this function: 902| bool 903| ABIMacOSX_i386::RegisterIsCalleeSaved (const RegisterInfo *reg_info) 904| { 905| if (reg_info) 906| { 907| // Saved registers are ebx, ebp, esi, edi, esp, eip 908| const char *name = reg_info->name; 909| if (name[0] == 'e') 910| { reg_info->name is "rip", and so ABIMacOSX_i386::RegisterIsCalleeSaved() is returning false. ABIMacOSX_i386.cpp looks like it does several things using register names. > Actually, RegisterContext_i386 doesn't get used in the case of a 32-bit inferior on a 64-bit host. In that scenario we use RegisterContext_x86_64 and do some mapping under the covers for 32-bit targets. Does this mean this is an issue with RegisterContext_x86_64 returning "rip" and not "eip"? Thanks. -Mike
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