Run all threads when extending a next range over a call.

If you don't do this you end up running arbitrary code with
only one thread allowed to run, which can cause deadlocks.

<rdar://problem/56422478>

Differential Revision: https://reviews.llvm.org/D71440

2 files changed, 12 insertions, 1 deletions

diff --git a/lldb/include/lldb/Core/Disassembler.h b/lldb/include/lldb/Core/Disassembler.h
index ba9ca87832f..7ece0eeb708 100644
--- a/lldb/include/lldb/Core/Disassembler.h
+++ b/lldb/include/lldb/Core/Disassembler.h
@@ -287,6 +287,10 @@ public:
   ///     a function call (a branch that calls and returns to the next
   ///     instruction). If false, find the instruction index of any 
   ///     branch in the list.
+  ///     
+  /// @param[out] found_calls
+  ///     If non-null, this will be set to true if any calls were found in 
+  ///     extending the range.
   ///    
   /// @return
   ///     The instruction index of the first branch that is at or past
@@ -295,7 +299,8 @@ public:
   //------------------------------------------------------------------
   uint32_t GetIndexOfNextBranchInstruction(uint32_t start,
                                            Target &target,
-                                           bool ignore_calls) const;
+                                           bool ignore_calls,
+                                           bool *found_calls) const;
 
   uint32_t GetIndexOfInstructionAtLoadAddress(lldb::addr_t load_addr,
                                               Target &target);
diff --git a/lldb/include/lldb/Target/ThreadPlanStepRange.h b/lldb/include/lldb/Target/ThreadPlanStepRange.h
index 93d54ad7dfd..28209623a1e 100644
--- a/lldb/include/lldb/Target/ThreadPlanStepRange.h
+++ b/lldb/include/lldb/Target/ThreadPlanStepRange.h
@@ -76,6 +76,12 @@ protected:
   lldb::BreakpointSP m_next_branch_bp_sp;
   bool m_use_fast_step;
   bool m_given_ranges_only;
+  bool m_found_calls = false; // When we set the next branch breakpoint for
+                              // step over, we now extend them past call insns
+                              // that directly return.  But if we do that we
+                              // need to run all threads, or we might cause
+                              // deadlocks.  This tells us whether we found
+                              // any calls in setting the next branch breakpoint.
 
 private:
   std::vector<lldb::DisassemblerSP> m_instruction_ranges;