1 files changed, 25 insertions, 7 deletions

diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h b/lldb/include/lldb/Symbol/UnwindPlan.h
index 40814da3de4a..cc2302d25831 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -71,7 +71,7 @@ public:
         isDWARFExpression  // reg = eval(dwarf_expr)
       };
 
-      RegisterLocation() : m_type(unspecified), m_location() {}
+      RegisterLocation() : m_location() {}
 
       bool operator==(const RegisterLocation &rhs) const;
 
@@ -181,7 +181,7 @@ public:
                 const UnwindPlan::Row *row, Thread *thread, bool verbose) const;
 
     private:
-      RestoreType m_type; // How do we locate this register?
+      RestoreType m_type = unspecified; // How do we locate this register?
       union {
         // For m_type == atCFAPlusOffset or m_type == isCFAPlusOffset
         int32_t offset;
@@ -205,7 +205,7 @@ public:
         isRaSearch,             // FA = SP + offset + ???
       };
 
-      FAValue() : m_type(unspecified), m_value() {}
+      FAValue() : m_value() {}
 
       bool operator==(const FAValue &rhs) const;
 
@@ -301,7 +301,7 @@ public:
       void Dump(Stream &s, const UnwindPlan *unwind_plan, Thread *thread) const;
 
     private:
-      ValueType m_type; // How do we compute CFA value?
+      ValueType m_type = unspecified; // How do we compute CFA value?
       union {
         struct {
           // For m_type == isRegisterPlusOffset or m_type ==
@@ -322,8 +322,6 @@ public:
 
     Row();
 
-    Row(const UnwindPlan::Row &rhs) = default;
-
     bool operator==(const Row &rhs) const;
 
     bool GetRegisterInfo(uint32_t reg_num,
@@ -360,6 +358,25 @@ public:
 
     bool SetRegisterLocationToSame(uint32_t reg_num, bool must_replace);
 
+    // When this UnspecifiedRegistersAreUndefined mode is
+    // set, any register that is not specified by this Row will
+    // be described as Undefined.
+    // This will prevent the unwinder from iterating down the
+    // stack looking for a spill location, or a live register value
+    // at frame 0.
+    // It would be used for an UnwindPlan row where we can't track
+    // spilled registers -- for instance a jitted stack frame where
+    // we have no unwind information or start address -- and registers
+    // MAY have been spilled and overwritten, so providing the
+    // spilled/live value from a newer frame may show an incorrect value.
+    void SetUnspecifiedRegistersAreUndefined(bool unspec_is_undef) {
+      m_unspecified_registers_are_undefined = unspec_is_undef;
+    }
+
+    bool GetUnspecifiedRegistersAreUndefined() {
+      return m_unspecified_registers_are_undefined;
+    }
+
     void Clear();
 
     void Dump(Stream &s, const UnwindPlan *unwind_plan, Thread *thread,
@@ -367,11 +384,12 @@ public:
 
   protected:
     typedef std::map<uint32_t, RegisterLocation> collection;
-    lldb::addr_t m_offset; // Offset into the function for this row
+    lldb::addr_t m_offset = 0; // Offset into the function for this row
 
     FAValue m_cfa_value;
     FAValue m_afa_value;
     collection m_register_locations;
+    bool m_unspecified_registers_are_undefined = false;
   }; // class Row
 
   typedef std::shared_ptr<Row> RowSP;