Improve instruction emulation based stack unwinding on ARM

* Add and fix the emulation of several instruction.
* Disable frame pointer usage on Android.
* Specify return address register for the unwind plan instead of explict
  tracking the value of RA.
* Replace prologue detection heuristics (unreliable in several cases)
  with a logic to follow the branch instructions and restore the CFI
  value based on them. The target address for a branch should have the
  same CFI as the source address (if they are in the same function).
* Handle symbols in ELF files where the symbol size is not specified
  with calcualting their size based on the next symbol (already done
  in MachO files).
* Fix architecture in FuncUnwinders with filling up the inforamtion
  missing from the object file with the architecture of the target.
* Add code to read register wehn the value is set to "IsSame" as it
  meanse the value of a register in the parent frame is the same as the
  value in the current frame.

Differential revision: http://reviews.llvm.org/D10447

llvm-svn: 240533

1 files changed, 7 insertions, 6 deletions

diff --git a/lldb/source/Symbol/FuncUnwinders.cpp b/lldb/source/Symbol/FuncUnwinders.cpp
index a36d5546b04..000df722bb9 100644
--- a/lldb/source/Symbol/FuncUnwinders.cpp
+++ b/lldb/source/Symbol/FuncUnwinders.cpp
@@ -154,7 +154,7 @@ FuncUnwinders::GetEHFrameAugmentedUnwindPlan (Target &target, Thread &thread, in
     // Augment the eh_frame instructions with epilogue descriptions if necessary so the
     // UnwindPlan can be used at any instruction in the function.
 
-    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler());
+    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler(target));
     if (assembly_profiler_sp)
     {
         if (!assembly_profiler_sp->AugmentUnwindPlanFromCallSite (m_range, thread, *m_unwind_plan_eh_frame_augmented_sp))
@@ -179,7 +179,7 @@ FuncUnwinders::GetAssemblyUnwindPlan (Target &target, Thread &thread, int curren
     Mutex::Locker lock (m_mutex);
     m_tried_unwind_plan_assembly = true;
 
-    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler());
+    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler(target));
     if (assembly_profiler_sp)
     {
         m_unwind_plan_assembly_sp.reset (new UnwindPlan (lldb::eRegisterKindGeneric));
@@ -204,7 +204,7 @@ FuncUnwinders::GetUnwindPlanAtNonCallSite (Target& target, Thread& thread, int c
 }
 
 UnwindPlanSP
-FuncUnwinders::GetUnwindPlanFastUnwind (Thread& thread)
+FuncUnwinders::GetUnwindPlanFastUnwind (Target& target, Thread& thread)
 {
     if (m_unwind_plan_fast_sp.get() || m_tried_unwind_fast)
         return m_unwind_plan_fast_sp;
@@ -212,7 +212,7 @@ FuncUnwinders::GetUnwindPlanFastUnwind (Thread& thread)
     Mutex::Locker locker (m_mutex);
     m_tried_unwind_fast = true;
 
-    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler());
+    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler(target));
     if (assembly_profiler_sp)
     {
         m_unwind_plan_fast_sp.reset (new UnwindPlan (lldb::eRegisterKindGeneric));
@@ -287,7 +287,7 @@ FuncUnwinders::GetFirstNonPrologueInsn (Target& target)
 
     Mutex::Locker locker (m_mutex);
     ExecutionContext exe_ctx (target.shared_from_this(), false);
-    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler());
+    UnwindAssemblySP assembly_profiler_sp (GetUnwindAssemblyProfiler(target));
     if (assembly_profiler_sp)
         assembly_profiler_sp->FirstNonPrologueInsn (m_range, exe_ctx, m_first_non_prologue_insn);
     return m_first_non_prologue_insn;
@@ -300,12 +300,13 @@ FuncUnwinders::GetFunctionStartAddress () const
 }
 
 lldb::UnwindAssemblySP
-FuncUnwinders::GetUnwindAssemblyProfiler ()
+FuncUnwinders::GetUnwindAssemblyProfiler (Target& target)
 {
     UnwindAssemblySP assembly_profiler_sp;
     ArchSpec arch;
     if (m_unwind_table.GetArchitecture (arch))
     {
+        arch.MergeFrom (target.GetArchitecture ());
         assembly_profiler_sp = UnwindAssembly::FindPlugin (arch);
     }
     return assembly_profiler_sp;