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<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Sure. Thanks a lot for suggesting this.<o:p></o:p></span></a></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks & Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Abhishek Aggarwal<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 6:01 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>
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<p class="MsoNormal">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 <span style="font-size:10.0pt">TestRegisters.py on FreeBSD".</span><o:p></o:p></p>
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<p class="MsoNormal"><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 7:59 AM Aggarwal, Abhishek A <<a href="mailto:abhishek.a.aggarwal@intel.com" target="_blank">abhishek.a.aggarwal@intel.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><a name="msg-f:1514298106697097813_msg-f:15142943"><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.</span></a><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">-Thanks</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><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:<a href="mailto:zturner@google.com" target="_blank">zturner@google.com</a>]
<br>
<b>Sent:</b> Tuesday, October 6, 2015 4:53 PM<br>
<b>To:</b> Aggarwal, Abhishek A; <a href="mailto:lldb-commits@lists.llvm.org" target="_blank">
lldb-commits@lists.llvm.org</a><br>
<b>Subject:</b> Re: [Lldb-commits] [lldb] r249379 - Bug 25050: X87 FPU Special Purpose Registers</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Tue, Oct 6, 2015 at 12:05 AM Abhishek Aggarwal via lldb-commits <<a href="mailto:lldb-commits@lists.llvm.org" target="_blank">lldb-commits@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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>
_______________________________________________<br>
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