Change type of m_user_expression_start_pos to size_t

AbsPosToLineColumnPos is the only reader of m_user_expression_start_pos
and actually treats it like a size_t. Also the value we store in
m_user_expression_start_pos is originally a size_t, so it makes sense
to change the type of this variable to size_t.

llvm-svn: 342804

lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp

@@ -620,7 +620,7 @@ bool ClangUserExpression::Parse(DiagnosticManager &diagnostic_manager,
 ///     The column in the line that contains the absolute position.
 ///     The first character in a line is indexed as 0.
 //------------------------------------------------------------------
-static void AbsPosToLineColumnPos(unsigned abs_pos, llvm::StringRef code,
+static void AbsPosToLineColumnPos(size_t abs_pos, llvm::StringRef code,
                                   unsigned &line, unsigned &column) {
   // Reset to code position to beginning of the file.
   line = 0;

lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h

@@ -204,7 +204,7 @@ private:
   /// The absolute character position in the transformed source code where the
   /// user code (as typed by the user) starts. If the variable is empty, then we
   /// were not able to calculate this position.
-  llvm::Optional<unsigned> m_user_expression_start_pos;
+  llvm::Optional<size_t> m_user_expression_start_pos;
   ResultDelegate m_result_delegate;
 };