Displaying the IAR Linker summary

By default, CMake will suppress the output provided by the underlying build tools, though sometimes it is convenient to get some output at build-time such as the binary's resource consumption provided by the IAR ILINK linker's summary. In this article, we will explore one way of overriding CMake's default behavior.

Helpful Resources

• option()
• if()
• string()
• CMAKE_EXE_LINKER_FLAGS
• cmake -D

Description

Starting from CMake 3.27, the IAR linker's --silent flag is not hardcoded. A CMake option() can be used to choose when to display the linker-provided information.

For example, configuring for the IAR Build Tools for Arm (CX):

$ cd tutorial
$ mkdir build
$ cd build

$ cmake .. -G Ninja --toolchain ../cxarm.cmake
-- The C compiler identification is IAR ARM 10.10.2
-- The CXX compiler identification is IAR ARM 10.10.2
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /opt/iar/cxarm/arm/bin/iccarm - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/iar/cxarm/arm/bin/iccarm - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done (0.4s)
-- Generating done (0.0s)
-- Build files have been written to: /path/to/cmake-tutorial/tutorial/build

And then:

$ cmake --build .
[2/2] Linking C executable tutorial.elf

Customizing your toolchain file

To display the summary by default, append the following snippet to your toolchain file:

option(ISPLAY_LINKER_SUMMARY "Display linker resource usage" ON)
if(ISPLAY_LINKER_SUMMARY)
  string(REGEX REPLACE "(^| )(--silent|-S)($| )" " " CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
endif()

And then, rebuild:

$ cmake --build .
[0/1] Re-running CMake...
-- Configuring done (0.0s)
-- Generating done (0.0s)
-- Build files have been written to: /path/to/cmake-tutorial/tutorial/build
[1/1] Linking C executable tutorial.elf

   IAR ELF Linker V10.10.2.628/LNX for ARM
   Copyright 2007-2026 IAR Systems AB.

   1'086 bytes of readonly  code memory
      97 bytes of readonly  data memory
  16'548 bytes of readwrite data memory

Errors: none
Warnings: none

Link time:   0.02 (CPU)   0.11 (elapsed)

Hiding the linker summary

To temporarily disable the -DISPLAY_LINKER_SUMMARY option, reconfigure the project:

$ cmake .. -DISPLAY_LINKER_SUMMARY=OFF
-- Configuring done (0.0s)
-- Generating done (0.0s)
-- Build files have been written to: /path/to/cmake-tutorial/tutorial/build

And rebuild:

$ cmake --build .
[1/1] Linking C executable tutorial.elf

The linker map summary was temporarily suppressed as in the default CMake behavior.