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<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">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.<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">-Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Zachary Turner [mailto:zturner@google.com]
<br>
<b>Sent:</b> Tuesday, October 6, 2015 4:53 PM<br>
<b>To:</b> Aggarwal, Abhishek A; lldb-commits@lists.llvm.org<br>
<b>Subject:</b> Re: [Lldb-commits] [lldb] r249379 - Bug 25050: X87 FPU Special Purpose Registers<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">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?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Tue, Oct 6, 2015 at 12:05 AM Abhishek Aggarwal via lldb-commits <<a href="mailto:lldb-commits@lists.llvm.org">lldb-commits@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<p class="MsoNormal">Author: abhishek<br>
Date: Tue Oct 6 02:04:03 2015<br>
New Revision: 249379<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=249379&view=rev" target="_blank">
http://llvm.org/viewvc/llvm-project?rev=249379&view=rev</a><br>
Log:<br>
Bug 25050: X87 FPU Special Purpose Registers<br>
<br>
Summary:<br>
- For x86_64-FreeBSD Platform:<br>
-- LLDB now provides correct values of X87 FPU<br>
Special Purpose Registers like fstat, ftag, fctrl etc..<br>
<br>
Signed-off-by: Abhishek Aggarwal <<a href="mailto:abhishek.a.aggarwal@intel.com" target="_blank">abhishek.a.aggarwal@intel.com</a>><br>
<br>
Reviewers: emaste, mikesart, clayborg<br>
<br>
Subscribers: emaste<br>
<br>
Differential Revision: <a href="http://reviews.llvm.org/D13434" target="_blank">http://reviews.llvm.org/D13434</a><br>
<br>
Modified:<br>
lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp<br>
lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h<br>
<br>
Modified: lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp?rev=249379&r1=249378&r2=249379&view=diff" target="_blank">
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp?rev=249379&r1=249378&r2=249379&view=diff</a><br>
==============================================================================<br>
--- lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp (original)<br>
+++ lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.cpp Tue Oct 6 02:04:03 2015<br>
@@ -58,6 +58,9 @@ RegisterContextPOSIXProcessMonitor_x86_6<br>
lldb_private::RegisterInfoInterface *register_info)<br>
: RegisterContextPOSIX_x86(thread, concrete_frame_idx, register_info)<br>
{<br>
+ // Store byte offset of fctrl (i.e. first register of FPR) wrt 'UserArea'<br>
+ const RegisterInfo *reg_info_fctrl = GetRegisterInfoByName("fctrl");<br>
+ m_fctrl_offset_in_userarea = reg_info_fctrl->byte_offset;<br>
}<br>
<br>
ProcessMonitor &<br>
@@ -254,8 +257,15 @@ RegisterContextPOSIXProcessMonitor_x86_6<br>
}<br>
<br>
// Get pointer to m_fpr.xstate.fxsave variable and set the data from it.<br>
- assert (reg_info->byte_offset < sizeof(m_fpr));<br>
- uint8_t *src = (uint8_t *)&m_fpr + reg_info->byte_offset;<br>
+ // Byte offsets of all registers are calculated wrt 'UserArea' structure.<br>
+ // However, ReadFPR() reads fpu registers {using ptrace(PT_GETFPREGS,..)}<br>
+ // and stores them in 'm_fpr' (of type FPR structure). To extract values of fpu<br>
+ // registers, m_fpr should be read at byte offsets calculated wrt to FPR structure.<br>
+<br>
+ // Since, FPR structure is also one of the member of UserArea structure.<br>
+ // byte_offset(fpu wrt FPR) = byte_offset(fpu wrt UserArea) - byte_offset(fctrl wrt UserArea)<br>
+ assert ( (reg_info->byte_offset - m_fctrl_offset_in_userarea) < sizeof(m_fpr));<br>
+ uint8_t *src = (uint8_t *)&m_fpr + reg_info->byte_offset - m_fctrl_offset_in_userarea;<br>
switch (reg_info->byte_size)<br>
{<br>
case 2:<br>
@@ -308,8 +318,15 @@ RegisterContextPOSIXProcessMonitor_x86_6<br>
else<br>
{<br>
// Get pointer to m_fpr.xstate.fxsave variable and set the data to it.<br>
- assert (reg_info->byte_offset < sizeof(m_fpr));<br>
- uint8_t *dst = (uint8_t *)&m_fpr + reg_info->byte_offset;<br>
+ // Byte offsets of all registers are calculated wrt 'UserArea' structure.<br>
+ // However, WriteFPR() takes m_fpr (of type FPR structure) and writes only fpu<br>
+ // registers using ptrace(PT_SETFPREGS,..) API. Hence fpu registers should<br>
+ // be written in m_fpr at byte offsets calculated wrt FPR structure.<br>
+<br>
+ // Since, FPR structure is also one of the member of UserArea structure.<br>
+ // byte_offset(fpu wrt FPR) = byte_offset(fpu wrt UserArea) - byte_offset(fctrl wrt UserArea)<br>
+ assert ( (reg_info->byte_offset - m_fctrl_offset_in_userarea) < sizeof(m_fpr));<br>
+ uint8_t *dst = (uint8_t *)&m_fpr + reg_info->byte_offset - m_fctrl_offset_in_userarea;<br>
switch (reg_info->byte_size)<br>
{<br>
case 2:<br>
<br>
Modified: lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h?rev=249379&r1=249378&r2=249379&view=diff" target="_blank">
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h?rev=249379&r1=249378&r2=249379&view=diff</a><br>
==============================================================================<br>
--- lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h (original)<br>
+++ lldb/trunk/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_x86.h Tue Oct 6 02:04:03 2015<br>
@@ -91,6 +91,7 @@ protected:<br>
private:<br>
ProcessMonitor &<br>
GetMonitor();<br>
+ uint32_t m_fctrl_offset_in_userarea; // Offset of 'fctrl' in 'UserArea' Structure<br>
};<br>
<br>
#endif<br>
<br>
<br>
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<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits</a><o:p></o:p></p>
</blockquote>
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