Author: jmolenda
Date: Tue Nov 18 20:29:52 2014
New Revision: 222301
URL: http://llvm.org/viewvc/llvm-project?rev=222301&view=rev
Log:
Add additional checks to the SavedLocationForRegister method
where it is retrieving the Return Address register contents
on a target where that's a thing. If we fail to get a valid
RA, we force a switch to the fallback unwind plan. This patch
adds a sanity check for that fallback unwind plan -- it must
get a valid CFA for this frame in addition to being able to
retrieve the caller's PC -- and it correctly marks the unwind
rules as failing if the fallback unwind plan fails.
<rdar://problem/19010211>
Modified:
lldb/trunk/source/Plugins/Process/Utility/RegisterContextLLDB.cpp
Modified: lldb/trunk/source/Plugins/Process/Utility/RegisterContextLLDB.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Utility/RegisterContextLLDB.cpp?rev=222301&r1=222300&r2=222301&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Utility/RegisterContextLLDB.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Utility/RegisterContextLLDB.cpp Tue Nov
18 20:29:52 2014
@@ -1267,12 +1267,30 @@ RegisterContextLLDB::SavedLocationForReg
// Throw away the full unwindplan; install the arch default
unwindplan
if (ForceSwitchToFallbackUnwindPlan())
{
- // Now re-fetch the pc value we're searching for
- RegisterNumber arch_default_pc_reg (m_thread,
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
+ // Update for the possibly new unwind plan
+ unwindplan_registerkind =
m_full_unwind_plan_sp->GetRegisterKind ();
UnwindPlan::RowSP active_row =
m_full_unwind_plan_sp->GetRowForFunctionOffset (m_current_offset);
- if (arch_default_pc_reg.GetAsKind
(unwindplan_registerkind) != LLDB_INVALID_REGNUM
- && active_row
- && active_row->GetRegisterInfo
(arch_default_pc_reg.GetAsKind (unwindplan_registerkind), unwindplan_regloc))
+
+ // Sanity check: Verify that we can fetch a pc value and
CFA value with this unwind plan
+
+ RegisterNumber arch_default_pc_reg (m_thread,
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
+ bool can_fetch_pc_value = false;
+ bool can_fetch_cfa = false;
+ addr_t cfa_value;
+ if (active_row)
+ {
+ if (arch_default_pc_reg.GetAsKind
(unwindplan_registerkind) != LLDB_INVALID_REGNUM
+ && active_row->GetRegisterInfo
(arch_default_pc_reg.GetAsKind (unwindplan_registerkind), unwindplan_regloc))
+ {
+ can_fetch_pc_value = true;
+ }
+ if (ReadCFAValueForRow (unwindplan_registerkind,
active_row, cfa_value))
+ {
+ can_fetch_cfa = true;
+ }
+ }
+
+ if (can_fetch_pc_value && can_fetch_cfa)
{
have_unwindplan_regloc = true;
}
@@ -1281,6 +1299,11 @@ RegisterContextLLDB::SavedLocationForReg
have_unwindplan_regloc = false;
}
}
+ else
+ {
+ // We were unable to fall back to another unwind plan
+ have_unwindplan_regloc = false;
+ }
}
}
}
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