[Lldb-commits] [lldb] r249379 - Bug 25050: X87 FPU Special Purpose Registers
Zachary Turner via lldb-commits
lldb-commits at lists.llvm.org
Tue Oct 6 09:01:07 PDT 2015
I see. In the future in this kind of situation could you mention in the
commit message what test this fixes. For example, "This fixes TestRegisters.py
on FreeBSD".
On Tue, Oct 6, 2015 at 7:59 AM Aggarwal, Abhishek A <
abhishek.a.aggarwal at intel.com> wrote:
> I had submitted a patch for the Bug 24457 which is similar kind of bug but
> on Linux x86_64 Platform. There, I had submitted a new test to reproduce
> this issue. The test is already there in public repository. Since, the same
> test goes for FreeBSD also therefore I didn’t need to write a new one.
>
>
>
> -Thanks
>
>
>
>
>
> *From:* Zachary Turner [mailto:zturner at google.com]
> *Sent:* Tuesday, October 6, 2015 4:53 PM
> *To:* Aggarwal, Abhishek A; lldb-commits at lists.llvm.org
> *Subject:* Re: [Lldb-commits] [lldb] r249379 - Bug 25050: X87 FPU Special
> Purpose Registers
>
>
>
> Please don't submit CLs like this without a test in the future. This
> should be testable by writing some assembly to move a value into an FPU
> register, setting a breakpoint, then querying the register values. Can you
> submit this as a followup?
>
>
>
> On Tue, Oct 6, 2015 at 12:05 AM Abhishek Aggarwal via lldb-commits <
> lldb-commits at lists.llvm.org> wrote:
>
> Author: abhishek
> Date: Tue Oct 6 02:04:03 2015
> New Revision: 249379
>
> URL: http://llvm.org/viewvc/llvm-project?rev=249379&view=rev
> Log:
> Bug 25050: X87 FPU Special Purpose Registers
>
> Summary:
> - For x86_64-FreeBSD Platform:
> -- LLDB now provides correct values of X87 FPU
> Special Purpose Registers like fstat, ftag, fctrl etc..
>
> Signed-off-by: Abhishek Aggarwal <abhishek.a.aggarwal at intel.com>
>
> Reviewers: emaste, mikesart, clayborg
>
> Subscribers: emaste
>
> Differential Revision: http://reviews.llvm.org/D13434
>
> Modified:
>
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp
>
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h
>
> Modified:
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp?rev=249379&r1=249378&r2=249379&view=diff
>
> ==============================================================================
> ---
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp
> (original)
> +++
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp
> Tue Oct 6 02:04:03 2015
> @@ -58,6 +58,9 @@ RegisterContextPOSIXProcessMonitor_x86_6
>
> lldb_private::RegisterInfoInterface *register_info)
> : RegisterContextPOSIX_x86(thread, concrete_frame_idx, register_info)
> {
> + // Store byte offset of fctrl (i.e. first register of FPR) wrt
> 'UserArea'
> + const RegisterInfo *reg_info_fctrl = GetRegisterInfoByName("fctrl");
> + m_fctrl_offset_in_userarea = reg_info_fctrl->byte_offset;
> }
>
> ProcessMonitor &
> @@ -254,8 +257,15 @@ RegisterContextPOSIXProcessMonitor_x86_6
> }
>
> // Get pointer to m_fpr.xstate.fxsave variable and set the data from
> it.
> - assert (reg_info->byte_offset < sizeof(m_fpr));
> - uint8_t *src = (uint8_t *)&m_fpr + reg_info->byte_offset;
> + // Byte offsets of all registers are calculated wrt 'UserArea'
> structure.
> + // However, ReadFPR() reads fpu registers {using
> ptrace(PT_GETFPREGS,..)}
> + // and stores them in 'm_fpr' (of type FPR structure). To extract
> values of fpu
> + // registers, m_fpr should be read at byte offsets calculated wrt to
> FPR structure.
> +
> + // Since, FPR structure is also one of the member of UserArea
> structure.
> + // byte_offset(fpu wrt FPR) = byte_offset(fpu wrt UserArea) -
> byte_offset(fctrl wrt UserArea)
> + assert ( (reg_info->byte_offset - m_fctrl_offset_in_userarea) <
> sizeof(m_fpr));
> + uint8_t *src = (uint8_t *)&m_fpr + reg_info->byte_offset -
> m_fctrl_offset_in_userarea;
> switch (reg_info->byte_size)
> {
> case 2:
> @@ -308,8 +318,15 @@ RegisterContextPOSIXProcessMonitor_x86_6
> else
> {
> // Get pointer to m_fpr.xstate.fxsave variable and set the
> data to it.
> - assert (reg_info->byte_offset < sizeof(m_fpr));
> - uint8_t *dst = (uint8_t *)&m_fpr + reg_info->byte_offset;
> + // Byte offsets of all registers are calculated wrt
> 'UserArea' structure.
> + // However, WriteFPR() takes m_fpr (of type FPR structure)
> and writes only fpu
> + // registers using ptrace(PT_SETFPREGS,..) API. Hence fpu
> registers should
> + // be written in m_fpr at byte offsets calculated wrt FPR
> structure.
> +
> + // Since, FPR structure is also one of the member of UserArea
> structure.
> + // byte_offset(fpu wrt FPR) = byte_offset(fpu wrt UserArea) -
> byte_offset(fctrl wrt UserArea)
> + assert ( (reg_info->byte_offset - m_fctrl_offset_in_userarea)
> < sizeof(m_fpr));
> + uint8_t *dst = (uint8_t *)&m_fpr + reg_info->byte_offset -
> m_fctrl_offset_in_userarea;
> switch (reg_info->byte_size)
> {
> case 2:
>
> Modified:
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h?rev=249379&r1=249378&r2=249379&view=diff
>
> ==============================================================================
> ---
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h
> (original)
> +++
> lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h
> Tue Oct 6 02:04:03 2015
> @@ -91,6 +91,7 @@ protected:
> private:
> ProcessMonitor &
> GetMonitor();
> + uint32_t m_fctrl_offset_in_userarea; // Offset of 'fctrl' in
> 'UserArea' Structure
> };
>
> #endif
>
>
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