llunak created this revision.
llunak added reviewers: JosephTremoulet, jasonmolenda.
llunak added a project: LLDB.
Herald added a subscriber: JDevlieghere.
llunak requested review of this revision.
This fixes handle-abrt test on my x86_64 openSUSE 15.2. The regression was
introduced by 31e6dbe1c6a6e418bd65847610d5052cc59978b2.
What happens is that the the point of the breapoint the stack is:
frame #0: 0x00000000004006bb a.out`handler(sig=6) at main.c:7:5
frame #1: 0x00007ffff7a555a0 libc.so.6`__restore_rt
frame #2: 0x00007ffff7a55520 libc.so.6`raise + 272
frame #3: 0x00007ffff7a56b01 libc.so.6`abort + 337
frame #4: 0x00000000004006e9 a.out`abort_caller at main.c:12:5
frame #5: 0x0000000000400743 a.out`main at main.c:23:5
The frame for '__restore_rt' is set to be eTrapHandlerFrame. And its parent
'raise' is set so as well because of 'GetNextFrame()->m_frame_type ==
eTrapHandlerFrame '. And then the same is done for 'abort', which seems
incorrect, a frame two frames away from the trap frame should be an ordinary
frame that does not need special handling.
I don't have detailed enough knowledge of this are to be certain about what
happens, but this patch basically changes all 'GetNextFrame()->m_frame_type ==
eTrapHandlerFrame' to be false if the actual trap frame is only the next-next
frame. This fixes the handle-abrt test for me, and all the other tests still
pass. The actually affected code is the "if (behaves_like_zeroth_frame &&
process) {" block in RegisterContextUnwind::GetFullUnwindPlanForFrame(), merely
adding "&& false" there avoids the problem as well. Why disabling that code
matters here, I have no idea.
Repository:
rLLDB LLDB
https://reviews.llvm.org/D86417
Files:
lldb/include/lldb/Target/RegisterContextUnwind.h
lldb/source/Target/RegisterContextUnwind.cpp
Index: lldb/source/Target/RegisterContextUnwind.cpp
===================================================================
--- lldb/source/Target/RegisterContextUnwind.cpp
+++ lldb/source/Target/RegisterContextUnwind.cpp
@@ -655,7 +655,8 @@
// If we're in _sigtramp(), unwinding past this frame requires special
// knowledge.
- if (m_frame_type == eTrapHandlerFrame || m_frame_type == eDebuggerFrame)
+ if (m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame || m_frame_type ==
eDebuggerFrame)
return unwind_plan_sp;
unwind_plan_sp = func_unwinders_sp->GetUnwindPlanFastUnwind(
@@ -807,7 +808,9 @@
// section, so prefer that if available. On other platforms we may need to
// provide a platform-specific UnwindPlan which encodes the details of how to
// unwind out of sigtramp.
- if (m_frame_type == eTrapHandlerFrame && process) {
+ if ((m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame) &&
+ process) {
m_fast_unwind_plan_sp.reset();
unwind_plan_sp =
func_unwinders_sp->GetEHFrameUnwindPlan(process->GetTarget());
@@ -1099,7 +1102,8 @@
// so this method helps to disambiguate that.
bool RegisterContextUnwind::IsTrapHandlerFrame() const {
- return m_frame_type == eTrapHandlerFrame;
+ return m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame;
}
// A skip frame is a bogus frame on the stack -- but one where we're likely to
@@ -1216,9 +1220,10 @@
// value instead of the Return Address register.
// If $pc is not available, fall back to the RA reg.
UnwindPlan::Row::RegisterLocation scratch;
- if (m_frame_type == eTrapHandlerFrame &&
- active_row->GetRegisterInfo
- (pc_regnum.GetAsKind (unwindplan_registerkind), scratch)) {
+ if ((m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame) &&
+ active_row->GetRegisterInfo(
+ pc_regnum.GetAsKind(unwindplan_registerkind), scratch)) {
UnwindLogMsg("Providing pc register instead of rewriting to "
"RA reg because this is a trap handler and there is "
"a location for the saved pc register value.");
@@ -1769,7 +1774,7 @@
return;
}
- m_frame_type = eTrapHandlerFrame;
+ m_frame_type = eTrapHandlerParentFrame;
if (m_current_offset_backed_up_one != m_current_offset) {
// We backed up the pc by 1 to compute the symbol context, but
Index: lldb/include/lldb/Target/RegisterContextUnwind.h
===================================================================
--- lldb/include/lldb/Target/RegisterContextUnwind.h
+++ lldb/include/lldb/Target/RegisterContextUnwind.h
@@ -71,6 +71,7 @@
enum FrameType {
eNormalFrame,
eTrapHandlerFrame,
+ eTrapHandlerParentFrame, // a parent frame of eTrapHandlerFrame
eDebuggerFrame, // a debugger inferior function call frame; we get caller's
// registers from debugger
eSkipFrame, // The unwind resulted in a bogus frame but may get back on
Index: lldb/source/Target/RegisterContextUnwind.cpp
===================================================================
--- lldb/source/Target/RegisterContextUnwind.cpp
+++ lldb/source/Target/RegisterContextUnwind.cpp
@@ -655,7 +655,8 @@
// If we're in _sigtramp(), unwinding past this frame requires special
// knowledge.
- if (m_frame_type == eTrapHandlerFrame || m_frame_type == eDebuggerFrame)
+ if (m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame || m_frame_type == eDebuggerFrame)
return unwind_plan_sp;
unwind_plan_sp = func_unwinders_sp->GetUnwindPlanFastUnwind(
@@ -807,7 +808,9 @@
// section, so prefer that if available. On other platforms we may need to
// provide a platform-specific UnwindPlan which encodes the details of how to
// unwind out of sigtramp.
- if (m_frame_type == eTrapHandlerFrame && process) {
+ if ((m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame) &&
+ process) {
m_fast_unwind_plan_sp.reset();
unwind_plan_sp =
func_unwinders_sp->GetEHFrameUnwindPlan(process->GetTarget());
@@ -1099,7 +1102,8 @@
// so this method helps to disambiguate that.
bool RegisterContextUnwind::IsTrapHandlerFrame() const {
- return m_frame_type == eTrapHandlerFrame;
+ return m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame;
}
// A skip frame is a bogus frame on the stack -- but one where we're likely to
@@ -1216,9 +1220,10 @@
// value instead of the Return Address register.
// If $pc is not available, fall back to the RA reg.
UnwindPlan::Row::RegisterLocation scratch;
- if (m_frame_type == eTrapHandlerFrame &&
- active_row->GetRegisterInfo
- (pc_regnum.GetAsKind (unwindplan_registerkind), scratch)) {
+ if ((m_frame_type == eTrapHandlerFrame ||
+ m_frame_type == eTrapHandlerParentFrame) &&
+ active_row->GetRegisterInfo(
+ pc_regnum.GetAsKind(unwindplan_registerkind), scratch)) {
UnwindLogMsg("Providing pc register instead of rewriting to "
"RA reg because this is a trap handler and there is "
"a location for the saved pc register value.");
@@ -1769,7 +1774,7 @@
return;
}
- m_frame_type = eTrapHandlerFrame;
+ m_frame_type = eTrapHandlerParentFrame;
if (m_current_offset_backed_up_one != m_current_offset) {
// We backed up the pc by 1 to compute the symbol context, but
Index: lldb/include/lldb/Target/RegisterContextUnwind.h
===================================================================
--- lldb/include/lldb/Target/RegisterContextUnwind.h
+++ lldb/include/lldb/Target/RegisterContextUnwind.h
@@ -71,6 +71,7 @@
enum FrameType {
eNormalFrame,
eTrapHandlerFrame,
+ eTrapHandlerParentFrame, // a parent frame of eTrapHandlerFrame
eDebuggerFrame, // a debugger inferior function call frame; we get caller's
// registers from debugger
eSkipFrame, // The unwind resulted in a bogus frame but may get back on
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