diff --git a/openfpga/src/base/openfpga_sdc.cpp b/openfpga/src/base/openfpga_sdc.cpp
index bba115d3c..148f5414b 100644
--- a/openfpga/src/base/openfpga_sdc.cpp
+++ b/openfpga/src/base/openfpga_sdc.cpp
@@ -28,7 +28,7 @@ namespace openfpga {
 /********************************************************************
  * A wrapper function to call the PnR SDC generator of FPGA-SDC
  *******************************************************************/
-int write_pnr_sdc(OpenfpgaContext& openfpga_ctx,
+int write_pnr_sdc(const OpenfpgaContext& openfpga_ctx,
                   const Command& cmd, const CommandContext& cmd_context) {
 
   CommandOptionId opt_output_dir = cmd.option("file");
@@ -168,7 +168,7 @@ int write_sdc_disable_timing_configure_ports(const OpenfpgaContext& openfpga_ctx
 /********************************************************************
  * A wrapper function to call the analysis SDC generator of FPGA-SDC
  *******************************************************************/
-int write_analysis_sdc(OpenfpgaContext& openfpga_ctx,
+int write_analysis_sdc(const OpenfpgaContext& openfpga_ctx,
                        const Command& cmd, const CommandContext& cmd_context) {
 
   CommandOptionId opt_output_dir = cmd.option("file");
diff --git a/openfpga/src/base/openfpga_sdc.h b/openfpga/src/base/openfpga_sdc.h
index 03f4af03f..2dd97b72a 100644
--- a/openfpga/src/base/openfpga_sdc.h
+++ b/openfpga/src/base/openfpga_sdc.h
@@ -15,7 +15,7 @@
 /* begin namespace openfpga */
 namespace openfpga {
 
-int write_pnr_sdc(OpenfpgaContext& openfpga_ctx,
+int write_pnr_sdc(const OpenfpgaContext& openfpga_ctx,
                   const Command& cmd, const CommandContext& cmd_context); 
 
 int write_configuration_chain_sdc(const OpenfpgaContext& openfpga_ctx,
@@ -24,7 +24,7 @@ int write_configuration_chain_sdc(const OpenfpgaContext& openfpga_ctx,
 int write_sdc_disable_timing_configure_ports(const OpenfpgaContext& openfpga_ctx,
                                              const Command& cmd, const CommandContext& cmd_context);
 
-int write_analysis_sdc(OpenfpgaContext& openfpga_ctx,
+int write_analysis_sdc(const OpenfpgaContext& openfpga_ctx,
                        const Command& cmd, const CommandContext& cmd_context);
 
 } /* end namespace openfpga */
diff --git a/openfpga/src/base/openfpga_sdc_command.cpp b/openfpga/src/base/openfpga_sdc_command.cpp
index 17910a711..bf207c33f 100644
--- a/openfpga/src/base/openfpga_sdc_command.cpp
+++ b/openfpga/src/base/openfpga_sdc_command.cpp
@@ -72,7 +72,7 @@ ShellCommandId add_openfpga_write_pnr_sdc_command(openfpga::Shell<OpenfpgaContex
   /* Add command 'write_fabric_verilog' to the Shell */
   ShellCommandId shell_cmd_id = shell.add_command(shell_cmd, "generate SDC files to constrain the backend flow for FPGA fabric");
   shell.set_command_class(shell_cmd_id, cmd_class_id);
-  shell.set_command_execute_function(shell_cmd_id, write_pnr_sdc);
+  shell.set_command_const_execute_function(shell_cmd_id, write_pnr_sdc);
 
   /* Add command dependency to the Shell */
   shell.set_command_dependency(shell_cmd_id, dependent_cmds);
@@ -178,7 +178,7 @@ ShellCommandId add_openfpga_write_analysis_sdc_command(openfpga::Shell<OpenfpgaC
   /* Add command 'write_fabric_verilog' to the Shell */
   ShellCommandId shell_cmd_id = shell.add_command(shell_cmd, "generate SDC files for timing analysis a PnRed FPGA fabric mapped by a benchmark");
   shell.set_command_class(shell_cmd_id, cmd_class_id);
-  shell.set_command_execute_function(shell_cmd_id, write_analysis_sdc);
+  shell.set_command_const_execute_function(shell_cmd_id, write_analysis_sdc);
 
   /* Add command dependency to the Shell */
   shell.set_command_dependency(shell_cmd_id, dependent_cmds);