ravitheja updated this revision to Diff 60533.
ravitheja added a comment.
Making EH Frame CFI the full unwinder
when artificial symbols are found.
http://reviews.llvm.org/D21221
Files:
source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
source/Plugins/Process/Utility/RegisterContextLLDB.cpp
Index: source/Plugins/Process/Utility/RegisterContextLLDB.cpp
===================================================================
--- source/Plugins/Process/Utility/RegisterContextLLDB.cpp
+++ source/Plugins/Process/Utility/RegisterContextLLDB.cpp
@@ -210,12 +210,28 @@
m_frame_type = eNormalFrame;
}
+ // We've set m_frame_type and m_sym_ctx before these calls.
+
+ m_fast_unwind_plan_sp = GetFastUnwindPlanForFrame ();
+ m_full_unwind_plan_sp = GetFullUnwindPlanForFrame ();
+
// If we were able to find a symbol/function, set addr_range to the bounds of that symbol/function.
// else treat the current pc value as the start_pc and record no offset.
if (addr_range.GetBaseAddress().IsValid())
{
m_start_pc = addr_range.GetBaseAddress();
- if (m_current_pc.GetSection() == m_start_pc.GetSection())
+ if (m_sym_ctx.symbol->IsSynthetic())
+ {
+ // The current offset should be recalculated here. The m_current_offset is
+ // calculated from the base address of the symbol. The symbol can lie in the PLT
+ // (Procedure Linkage Table) i.e its a symbol stub for external call. In this case
+ // the base address for the unwindplan and the base address of the symbol maybe different, hence
+ // the m_current_offset will be wrong.
+ AddressRange unwind_address_range = m_full_unwind_plan_sp->GetAddressRange();
+ if (unwind_address_range.ContainsFileAddress(m_current_pc))
+ m_current_offset = m_current_pc.GetOffset() - unwind_address_range.GetBaseAddress().GetOffset();
+ }
+ else if (m_current_pc.GetSection() == m_start_pc.GetSection())
{
m_current_offset = m_current_pc.GetOffset() - m_start_pc.GetOffset();
}
@@ -236,11 +252,6 @@
m_current_offset_backed_up_one = -1;
}
- // We've set m_frame_type and m_sym_ctx before these calls.
-
- m_fast_unwind_plan_sp = GetFastUnwindPlanForFrame ();
- m_full_unwind_plan_sp = GetFullUnwindPlanForFrame ();
-
UnwindPlan::RowSP active_row;
lldb::RegisterKind row_register_kind = eRegisterKindGeneric;
if (m_full_unwind_plan_sp && m_full_unwind_plan_sp->PlanValidAtAddress (m_current_pc))
@@ -255,36 +266,14 @@
}
}
- if (!active_row.get())
- {
- UnwindLogMsg ("could not find an unwindplan row for this frame's pc");
- m_frame_type = eNotAValidFrame;
- return;
- }
-
-
if (!ReadCFAValueForRow (row_register_kind, active_row, m_cfa))
{
// Try the fall back unwind plan since the
// full unwind plan failed.
- FuncUnwindersSP func_unwinders_sp;
- UnwindPlanSP call_site_unwind_plan;
bool cfa_status = false;
+ if (TryFallbackUnwindPlan())
+ cfa_status = true;
- if (m_sym_ctx_valid)
- {
- func_unwinders_sp = pc_module_sp->GetObjectFile()->GetUnwindTable().GetFuncUnwindersContainingAddress (m_current_pc, m_sym_ctx);
- }
-
- if(func_unwinders_sp.get() != nullptr)
- call_site_unwind_plan = func_unwinders_sp->GetUnwindPlanAtCallSite(process->GetTarget(), m_current_offset_backed_up_one);
-
- if (call_site_unwind_plan.get() != nullptr)
- {
- m_fallback_unwind_plan_sp = call_site_unwind_plan;
- if(TryFallbackUnwindPlan())
- cfa_status = true;
- }
if (!cfa_status)
{
UnwindLogMsg ("could not read CFA value for first frame.");
@@ -881,6 +870,8 @@
// call GetUnwindPlanAtCallSite() -- because CallSite may return an unwind plan sourced from
// either eh_frame (that's what we intend) or compact unwind (this won't work)
unwind_plan_sp = func_unwinders_sp->GetEHFrameUnwindPlan (process->GetTarget(), m_current_offset_backed_up_one);
+ m_fallback_unwind_plan_sp = func_unwinders_sp->GetUnwindPlanAtNonCallSite (process->GetTarget(), m_thread, m_current_offset_backed_up_one);
+
if (unwind_plan_sp && unwind_plan_sp->PlanValidAtAddress (m_current_pc))
{
UnwindLogMsgVerbose ("frame uses %s for full UnwindPlan because the DynamicLoader suggested we prefer it",
@@ -1608,8 +1599,8 @@
// If a compiler generated unwind plan failed, trying the arch default unwindplan
// isn't going to do any better.
- if (m_full_unwind_plan_sp->GetSourcedFromCompiler() == eLazyBoolYes)
- return false;
+// if (m_full_unwind_plan_sp->GetSourcedFromCompiler() == eLazyBoolYes)
+// return false;
// Get the caller's pc value and our own CFA value.
@@ -1655,7 +1646,32 @@
m_full_unwind_plan_sp = m_fallback_unwind_plan_sp;
- UnwindPlan::RowSP active_row = m_fallback_unwind_plan_sp->GetRowForFunctionOffset (m_current_offset);
+ // The current offset should be recalculated here. The m_current_offset is
+ // calculated from the base address of the symbol. The symbol can lie in the PLT
+ // (Procedure Linkage Table) i.e its a symbol stub for external call. In this case
+ // the base address for the unwindplan and the base address of the symbol maybe different, hence
+ // the m_current_offset will be wrong.
+
+ int fallback_offset = m_current_offset;
+ AddressRange fall_back_unwind_address_range = m_fallback_unwind_plan_sp->GetAddressRange();
+ if (m_sym_ctx.symbol->IsSynthetic() && fall_back_unwind_address_range.ContainsFileAddress(m_current_pc))
+ {
+ fallback_offset = m_current_pc.GetOffset() - fall_back_unwind_address_range.GetBaseAddress().GetOffset();
+ }
+ else if (m_current_pc.GetSection() == m_start_pc.GetSection())
+ {
+ fallback_offset = m_current_pc.GetOffset() - m_start_pc.GetOffset();
+ }
+ else if (m_current_pc.GetModule() == m_start_pc.GetModule())
+ {
+ // This means that whatever symbol we kicked up isn't really correct
+ // --- we should not cross section boundaries ... We really should NULL out
+ // the function/symbol in this case unless there is a bad assumption
+ // here due to inlined functions?
+ fallback_offset = m_current_pc.GetFileAddress() - m_start_pc.GetFileAddress();
+ }
+
+ UnwindPlan::RowSP active_row = m_fallback_unwind_plan_sp->GetRowForFunctionOffset (fallback_offset);
if (active_row && active_row->GetCFAValue().GetValueType() != UnwindPlan::Row::CFAValue::unspecified)
{
@@ -1763,6 +1779,9 @@
const UnwindPlan::RowSP &row,
addr_t &cfa_value)
{
+ if (row.get() == nullptr)
+ return false;
+
RegisterValue reg_value;
cfa_value = LLDB_INVALID_ADDRESS;
Index: source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
===================================================================
--- source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
+++ source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
@@ -72,6 +72,9 @@
uint32_t
GetPluginVersion() override;
+ bool
+ AlwaysRelyOnEHUnwindInfo (lldb_private::SymbolContext &sym_ctx) override;
+
protected:
/// Runtime linker rendezvous structure.
DYLDRendezvous m_rendezvous;
Index: source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
===================================================================
--- source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -105,6 +105,14 @@
}
}
+bool
+DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo (SymbolContext &sym_ctx)
+{
+ if (sym_ctx.symbol->IsSynthetic())
+ return true;
+ return DynamicLoader::AlwaysRelyOnEHUnwindInfo(sym_ctx);
+}
+
void
DynamicLoaderPOSIXDYLD::DidAttach()
{
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