[Lldb-commits] [lldb] 4fdd2ed - Revert "Unwind past an interrupt handler correctly on arm or at pc==0"

[Jason Molenda via lldb-commits]

Author: Jason Molenda
Date: 2020-02-24T19:03:22-08:00
New Revision: 4fdd2edbdb4bfe6a95df0fac12e8beffcbe33b86

URL: https://github.com/llvm/llvm-project/commit/4fdd2edbdb4bfe6a95df0fac12e8beffcbe33b86
DIFF: https://github.com/llvm/llvm-project/commit/4fdd2edbdb4bfe6a95df0fac12e8beffcbe33b86.diff

LOG: Revert "Unwind past an interrupt handler correctly on arm or at pc==0"

The aarcht64-ubuntu bot is showing a test failure in TestHandleAbort.py
with this patch.  Adding some logging to that file, it looks like
the saved register context above the trap handler does not have
save state for $pc, but it does have it for $lr on that platform.
I need to fall back to looking for $lr if the $pc cannot be retrieved.
I'll update the patch and re-commit once that's fixed.

This reverts commit edc4f4c9c9d90b2a4f8831ba4c873f08eaa5395a.

Added: 
    

Modified: 
    lldb/source/Plugins/Process/Utility/RegisterContextLLDB.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/Plugins/Process/Utility/RegisterContextLLDB.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextLLDB.cpp
index d46b87281f11..56dd273c25b7 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextLLDB.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextLLDB.cpp
@@ -328,13 +328,9 @@ void RegisterContextLLDB::InitializeNonZerothFrame() {
 
   // If we don't have a Module for some reason, we're not going to find
   // symbol/function information - just stick in some reasonable defaults and
-  // hope we can unwind past this frame.  If we're above a trap handler,
-  // we may be at a bogus address because we jumped through a bogus function
-  // pointer and trapped, so don't force the arch default unwind plan in that 
-  // case.
+  // hope we can unwind past this frame.
   ModuleSP pc_module_sp(m_current_pc.GetModule());
-  if ((!m_current_pc.IsValid() || !pc_module_sp) &&
-      above_trap_handler == false) {
+  if (!m_current_pc.IsValid() || !pc_module_sp) {
     UnwindLogMsg("using architectural default unwind method");
 
     // Test the pc value to see if we know it's in an unmapped/non-executable
@@ -1207,13 +1203,9 @@ RegisterContextLLDB::SavedLocationForRegister(
       // If we're fetching the saved pc and this UnwindPlan defines a
       // ReturnAddress register (e.g. lr on arm), look for the return address
       // register number in the UnwindPlan's row.
-      // If this is a trap handler frame, we have access to the complete
-      // register context when the interrupt/async signal was received, so
-      // we need to fetch the actual saved $pc value.
       if (pc_regnum.IsValid() && pc_regnum == regnum &&
           m_full_unwind_plan_sp->GetReturnAddressRegister() !=
-              LLDB_INVALID_REGNUM &&
-          m_frame_type != eTrapHandlerFrame) {
+              LLDB_INVALID_REGNUM) {
 
         return_address_reg.init(
             m_thread, m_full_unwind_plan_sp->GetRegisterKind(),