[Lldb-commits] [lldb] r189576 - Discover support of 'p' packet.

[Sean Callanan]

Greg and I have looked at this, and we may have a fix.  The patch sent an exploratory ‘p’ packet that didn’t include the required thread suffix.
I’m testing the patch and will commit if it turns out to be okay.

Sean

On Sep 4, 2013, at 3:06 PM, Sean Callanan <scallanan at apple.com> wrote:

> I’ve investigated, and it looks to me like this commit breaks Mac OS X LLDB’s ability to write registers.
> –
> [r189575]
> (lldb) reg write rdx 0x03
> (lldb) reg read rdx
>      rdx = 0x0000000000000003
> 
> [r189576]
> (lldb) reg write rdx 0x03
> error: Failed to write register 'rdx' with value '0x03'
> –
> We should figure out what’s going on or roll this back as soon as possible, because that breaks the expression command on OS X among other things.
> 
> Sean
> 
> On Aug 29, 2013, at 2:09 AM, Hafiz Abid Qadeer <hafiz_abid at mentor.com> wrote:
> 
>> Author: abidh
>> Date: Thu Aug 29 04:09:45 2013
>> New Revision: 189576
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=189576&view=rev
>> Log:
>> Discover support of 'p' packet.
>> 
>> Some stubs only support g/G packets for registers.
>> This change makes sure that we check if remote stub supports 'p' packet before using it.
>> 
>> Modified:
>>    lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
>>    lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
>>    lldb/trunk/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp
>> 
>> Modified: lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp?rev=189576&r1=189575&r2=189576&view=diff
>> ==============================================================================
>> --- lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp (original)
>> +++ lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp Thu Aug 29 04:09:45 2013
>> @@ -55,6 +55,7 @@ GDBRemoteCommunicationClient::GDBRemoteC
>>     m_supports_vCont_C (eLazyBoolCalculate),
>>     m_supports_vCont_s (eLazyBoolCalculate),
>>     m_supports_vCont_S (eLazyBoolCalculate),
>> +    m_supports_p (eLazyBoolCalculate),
>>     m_qHostInfo_is_valid (eLazyBoolCalculate),
>>     m_qProcessInfo_is_valid (eLazyBoolCalculate),
>>     m_supports_alloc_dealloc_memory (eLazyBoolCalculate),
>> @@ -200,6 +201,7 @@ GDBRemoteCommunicationClient::ResetDisco
>>     m_supports_vCont_C = eLazyBoolCalculate;
>>     m_supports_vCont_s = eLazyBoolCalculate;
>>     m_supports_vCont_S = eLazyBoolCalculate;
>> +    m_supports_p = eLazyBoolCalculate;
>>     m_qHostInfo_is_valid = eLazyBoolCalculate;
>>     m_qProcessInfo_is_valid = eLazyBoolCalculate;
>>     m_supports_alloc_dealloc_memory = eLazyBoolCalculate;
>> @@ -295,6 +297,24 @@ GDBRemoteCommunicationClient::GetVContSu
>>     return false;
>> }
>> 
>> +// Check if the target supports 'p' packet. It sends out a 'p'
>> +// packet and checks the response. A normal packet will tell us
>> +// that support is available.
>> +bool
>> +GDBRemoteCommunicationClient::GetpPacketSupported ()
>> +{
>> +    if (m_supports_p == eLazyBoolCalculate)
>> +    {
>> +        StringExtractorGDBRemote response;
>> +        m_supports_p = eLazyBoolNo;
>> +        if (SendPacketAndWaitForResponse("p0", response, false))
>> +        {
>> +            if (response.IsNormalResponse())
>> +                m_supports_p = eLazyBoolYes;
>> +        }
>> +    }
>> +    return m_supports_p;
>> +}
>> 
>> size_t
>> GDBRemoteCommunicationClient::SendPacketAndWaitForResponse
>> 
>> Modified: lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
>> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h?rev=189576&r1=189575&r2=189576&view=diff
>> ==============================================================================
>> --- lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h (original)
>> +++ lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h Thu Aug 29 04:09:45 2013
>> @@ -228,6 +228,9 @@ public:
>>     GetVContSupported (char flavor);
>> 
>>     bool
>> +    GetpPacketSupported ();
>> +
>> +    bool
>>     GetVAttachOrWaitSupported ();
>> 
>>     bool
>> @@ -431,6 +434,7 @@ protected:
>>     lldb_private::LazyBool m_watchpoints_trigger_after_instruction;
>>     lldb_private::LazyBool m_attach_or_wait_reply;
>>     lldb_private::LazyBool m_prepare_for_reg_writing_reply;
>> +    lldb_private::LazyBool m_supports_p;
>> 
>>     bool
>>         m_supports_qProcessInfoPID:1,
>> 
>> Modified: lldb/trunk/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp?rev=189576&r1=189575&r2=189576&view=diff
>> ==============================================================================
>> --- lldb/trunk/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp (original)
>> +++ lldb/trunk/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp Thu Aug 29 04:09:45 2013
>> @@ -164,7 +164,6 @@ lldb::RegisterContextSP
>> ThreadGDBRemote::CreateRegisterContextForFrame (StackFrame *frame)
>> {
>>     lldb::RegisterContextSP reg_ctx_sp;
>> -    const bool read_all_registers_at_once = false;
>>     uint32_t concrete_frame_idx = 0;
>> 
>>     if (frame)
>> @@ -177,6 +176,8 @@ ThreadGDBRemote::CreateRegisterContextFo
>>         if (process_sp)
>>         {
>>             ProcessGDBRemote *gdb_process = static_cast<ProcessGDBRemote *>(process_sp.get());
>> +            // read_all_registers_at_once will be true if 'p' packet is not supported.
>> +            bool read_all_registers_at_once = !gdb_process->GetGDBRemote().GetpPacketSupported ();
>>             reg_ctx_sp.reset (new GDBRemoteRegisterContext (*this, concrete_frame_idx, gdb_process->m_register_info, read_all_registers_at_once));
>>         }
>>     }
>> 
>> 
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> 

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