Merge pull request #9383 from felipepiovezan/felipe/cherry_pick_fa_location_constant

[lldb] Add isConstant mode for FA locations (llvm#110726)

Author: felipepiovezan

lldb/include/lldb/Symbol/UnwindPlan.h

@@ -215,6 +215,7 @@ class UnwindPlan {
         isRegisterDereferenced, // FA = [reg]
         isDWARFExpression,      // FA = eval(dwarf_expr)
         isRaSearch,             // FA = SP + offset + ???
+        isConstant,             // FA = constant
       };
 
       FAValue() : m_value() {}
@@ -259,6 +260,15 @@ class UnwindPlan {
         m_value.expr.length = len;
       }
 
+      bool IsConstant() const { return m_type == isConstant; }
+
+      void SetIsConstant(uint64_t constant) {
+        m_type = isConstant;
+        m_value.constant = constant;
+      }
+
+      uint64_t GetConstant() const { return m_value.constant; }
+
       uint32_t GetRegisterNumber() const {
         if (m_type == isRegisterDereferenced || m_type == isRegisterPlusOffset)
           return m_value.reg.reg_num;
@@ -329,6 +339,8 @@ class UnwindPlan {
         } expr;
         // For m_type == isRaSearch
         int32_t ra_search_offset;
+        // For m_type = isConstant
+        uint64_t constant;
       } m_value;
     }; // class FAValue
 

lldb/source/Symbol/UnwindPlan.cpp

@@ -187,6 +187,8 @@ operator==(const UnwindPlan::Row::FAValue &rhs) const {
         return !memcmp(m_value.expr.opcodes, rhs.m_value.expr.opcodes,
                        m_value.expr.length);
       break;
+    case isConstant:
+      return m_value.constant == rhs.m_value.constant;
     }
   }
   return false;
@@ -214,6 +216,8 @@ void UnwindPlan::Row::FAValue::Dump(Stream &s, const UnwindPlan *unwind_plan,
   case isRaSearch:
     s.Printf("RaSearch@SP%+d", m_value.ra_search_offset);
     break;
+  case isConstant:
+    s.Printf("0x%" PRIx64, m_value.constant);
   }
 }
 

lldb/source/Target/RegisterContextUnwind.cpp

@@ -2088,6 +2088,12 @@ bool RegisterContextUnwind::ReadFrameAddress(
     UnwindLogMsg("No suitable CFA found");
     break;
   }
+  case UnwindPlan::Row::FAValue::isConstant: {
+    address = fa.GetConstant();
+    address = m_thread.GetProcess()->FixDataAddress(address);
+    UnwindLogMsg("CFA value set by constant is 0x%" PRIx64, address);
+    return true;
+  }
   default:
     return false;
   }