Merge branch 'tools/gcc_string_1byte_align' into 'master'

tools(lto): Support to set string 1-byte align to reduce firmware size

See merge request ae_group/esp-iot-solution!833

tools/cmake_utilities/CHANGELOG.md

@@ -1,3 +1,7 @@
+## v0.5.1 - 2023-08-22
+
+* Add string 1-byte align support
+
 ## v0.5.0 - 2023-08-02
 
 * Add GCC LTO support

tools/cmake_utilities/Kconfig

@@ -54,4 +54,12 @@ menu "CMake Utilities"
         help
             "Enable this option, users can enable GCC link time optimization(LTO)
              feature for target components or dependencies.
+
+    config CU_GCC_STRING_1BYTE_ALIGN
+        bool "GCC string 1-byte align"
+        default n
+        help
+            "Enable this option, user can make string in designated components align
+             by 1-byte instead 1-word(4-byte), this can reduce unnecessary filled data
+             so that to reduce firmware size."
 endmenu

tools/cmake_utilities/README.md

@@ -31,4 +31,4 @@ This component is aiming to provide some useful CMake utilities outside of ESP-I
 
 1. [relinker](https://github.com/espressif/esp-iot-solution/blob/master/tools/cmake_utilities/docs/relinker.md)
 2. [gen_compressed_ota](https://github.com/espressif/esp-iot-solution/blob/master/tools/cmake_utilities/docs/gen_compressed_ota.md)
-3. [Link Time Optimization](https://github.com/espressif/esp-iot-solution/blob/master/tools/cmake_utilities/docs/gcc_lto.md)
+3. [GCC Optimization](https://github.com/espressif/esp-iot-solution/blob/master/tools/cmake_utilities/docs/gcc.md)

tools/cmake_utilities/cmake_utilities.cmake

@@ -1,6 +1,6 @@
 # Include all cmake modules
 
-include(gcc_lto)
+include(gcc)
 include(gen_compressed_ota)
 include(gen_single_bin)
 include(package_manager)

tools/cmake_utilities/docs/gcc_lto.md → tools/cmake_utilities/docs/gcc.md

@@ -13,18 +13,21 @@ project(XXXX)
 
 include(cmake_utilities)
 #or
-include(gcc_lto)
+include(gcc)
 ```
 
-The LTO feature is disabled by default. To use it, you should enable the option `CU_GCC_LTO_ENABLE` in menuconfig. Then specify target components or dependencies to be optimized by LTO after `include(cmake_utilities)` or `include(gcc_lto)` as follows:
+The LTO feature is disabled by default. To use it, you should enable the option `CU_GCC_LTO_ENABLE` in menuconfig. Then specify target components or dependencies to be optimized by LTO after `include(cmake_utilities)` or `include(gcc)` as follows:
 
 ```cmake
 include(cmake_utilities)
 #or
-include(gcc_lto)
+include(gcc)
 
 cu_gcc_lto_set(COMPONENTS component_a component_b
                DEPENDS dependence_a dependence_b)
+
+cu_gcc_string_1byte_align(COMPONENTS component_c component_d
+                          DEPENDS dependence_c dependence_d)
 ```
 
 Based on your requirement, set compiling optimization level in the option `COMPILER_OPTIMIZATION`.
@@ -36,6 +39,7 @@ Based on your requirement, set compiling optimization level in the option `COMPI
     2. Increasing performance may increase firmware size
     3. Enable LTO cause compiling time cost increases a lot
     4. Enable LTO may increase task stack cost
+    5. Enable string 1-byte align may decrease string process speed
     ```
 
 ## Limitation
@@ -69,7 +73,7 @@ project(light)
 # Add
 include(cmake_utilities)
 #or
-include(gcc_lto)
+include(gcc)
 
 # Add
 set(app_lto_components main chip esp_matter)
@@ -81,7 +85,7 @@ set(lto_depends mbedcrypto)
 # Add
 cu_gcc_lto_set(COMPONENTS ${app_lto_components} ${idf_lto_components} 
                DEPENDS ${lto_depends})
-````
+```
 
 Configure `ESP32-C2` as the target platform, enable `CU_GCC_LTO_ENABLE` and `CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_DISABLE`, set `COMPILER_OPTIMIZATION` to be `-Os`.
 Increase the `main` task stack size to `5120` by option `ESP_MAIN_TASK_STACK_SIZE`.
@@ -91,3 +95,21 @@ Option | Firmware size | Stask cost
 |:-:|:-:|:-:|
  -Os | 1,113,376 | 2508
  -Os + LTO | 1,020,640 | 4204
+
+Then add `cu_gcc_string_1byte_align` after `cu_gcc_lto_set`:
+
+```cmake
+# Add
+cu_gcc_lto_set(COMPONENTS ${app_lto_components} ${idf_lto_components} 
+               DEPENDS ${lto_depends})
+
+cu_gcc_string_1byte_align(COMPONENTS ${app_lto_components} ${idf_lto_components} 
+                          DEPENDS ${lto_depends})
+```
+
+Build the project and the firmware size is:
+
+Option | Firmware size |
+|:-:|:-:|:-:|
+ -Os + LTO | 1,020,640 |
+ -Os + LTO + string 1-byte align | 1,018,340 |

tools/cmake_utilities/gcc_lto.cmake → tools/cmake_utilities/gcc.cmake

@@ -54,3 +54,27 @@ else()
         message(STATUS "GCC link time optimization(LTO) is not enable")
     endmacro()
 endif()
+
+if(CONFIG_CU_GCC_STRING_1BYTE_ALIGN)
+    macro(cu_gcc_string_1byte_align)
+        message(STATUS "GCC string 1-byte align is enable")
+
+        set(multi_value COMPONENTS DEPENDS)
+        cmake_parse_arguments(STR_ALIGN "" "" "${multi_value}" ${ARGN})
+
+        message(STATUS "GCC string 1-byte align for components: ${STR_ALIGN_COMPONENTS}")
+        foreach(c ${STR_ALIGN_COMPONENTS})
+            idf_component_get_property(t ${c} COMPONENT_LIB)
+            target_compile_options(${t} PRIVATE "-malign-data=natural")
+        endforeach()
+
+        message(STATUS "GCC string 1-byte align for dependencies: ${STR_ALIGN_DEPENDS}")
+        foreach(d ${STR_ALIGN_DEPENDS})
+            target_compile_options(${d} PRIVATE "-malign-data=natural")
+        endforeach()
+    endmacro()
+else()
+    macro(cu_gcc_string_1byte_align)
+        message(STATUS "GCC string 1-byte align is not enable")
+    endmacro()
+endif()

tools/cmake_utilities/idf_component.yml

@@ -1,4 +1,4 @@
-version: "0.5.0"
+version: "0.5.1"
 description: A collection of useful cmake utilities
 url: https://github.com/espressif/esp-iot-solution/tree/master/tools/cmake_utilities
 issues: https://github.com/espressif/esp-iot-solution/issues