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.aggar...@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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