cmake: Fix psram workaround compiler flag application

Previously, this compiler flag was not being applied
regardless of CONFIG_SPIRAM_CACHE_WORKAROUND setting.

Explanation: add_compile_options() only applies to
source files added after the function is run, or in
subdirectories added after the function is run. In
this case, no new source files were being added after
this function was run.

components/esp32/CMakeLists.txt

@@ -96,7 +96,10 @@ else()
         )
 
     if(CONFIG_SPIRAM_CACHE_WORKAROUND)
-        add_compile_options(-mfix-esp32-psram-cache-issue)
+        # Note: Adding as a PUBLIC compile option here causes this option to propagate to all components that depend on esp32.
+        #
+        # To handle some corner cases, the same flag is set in project_include.cmake
+        target_compile_options(${COMPONENT_TARGET} PUBLIC -mfix-esp32-psram-cache-issue)
     else()
         target_linker_script(${COMPONENT_TARGET} "ld/esp32.rom.spiram_incompatible_fns.ld")
     endif()

components/esp32/Kconfig

@@ -132,7 +132,8 @@ menu "ESP32-specific"
             help
                 Revision 1 of the ESP32 has a bug that can cause a write to PSRAM not to take place in some situations
                 when the cache line needs to be fetched from external RAM and an interrupt occurs. This enables a
-                fix in the compiler that makes sure the specific code that is vulnerable to this will not be emitted.
+                fix in the compiler (-mfix-esp32-psram-cache-issue) that makes sure the specific code that is
+                vulnerable to this will not be emitted.
 
                 This will also not use any bits of newlib that are located in ROM, opting for a version that is
                 compiled with the workaround and located in flash instead.

components/esp32/project_include.cmake

@@ -0,0 +1,8 @@
+if(CONFIG_SPIRAM_CACHE_WORKAROUND)
+    # We do this here as well as in CMakeLists.txt, because targets that
+    # are not part of the ESP-IDF build system (for cases where a generic
+    # non-IDF CMakeLists.txt file is imported into a component) don't depend
+    # on the esp32 component so don't get the extra flag. This handles that case.
+    add_compile_options(-mfix-esp32-psram-cache-issue)
+endif()
+

docs/en/api-guides/build-system-cmake.rst

@@ -775,6 +775,8 @@ the ESP-IDF build system entirely by using a CMake feature called ExternalProjec
 - The second set of commands adds a library target, which points to the "imported" library file built by the external system. Some properties need to be set in order to add include directories and tell CMake where this file is.
 - Finally, the generated library is added to `ADDITIONAL_MAKE_CLEAN_FILES`_. This means ``make clean`` will delete this library. (Note that the other object files from the build won't be deleted.)
 
+.. note:: When using an external build process with PSRAM, remember to add ``-mfix-esp32-psram-cache-issue`` to the C compiler arguments. See :ref:`CONFIG_SPIRAM_CACHE_WORKAROUND` for details of this flag.
+
 .. _ADDITIONAL_MAKE_CLEAN_FILES_note:
 
 ExternalProject dependencies, clean builds
@@ -961,6 +963,8 @@ parameters which can be set, the full list of which is as follows:
 The example in :example:`build_system/cmake/idf_as_lib` demonstrates the creation of an application equivalent to :example:`hello world application <get-started/hello_world>`
 using a custom CMake project.
 
+.. note:: The IDF build system can only set compiler flags for source files that it builds. When an external CMakeLists.txt file is used and PSRAM is enabled, remember to add ``-mfix-esp32-psram-cache-issue`` to the C compiler arguments. See :ref:`CONFIG_SPIRAM_CACHE_WORKAROUND` for details of this flag.
+
 .. _cmake-file-globbing:
 
 File Globbing & Incremental Builds

docs/en/api-guides/build-system.rst

@@ -614,6 +614,7 @@ $(COMPONENT_LIBRARY) for the project make process to link into the app binary.
 (Actually, even this is not strictly necessary - if the COMPONENT_ADD_LDFLAGS variable
 is overridden then the component can instruct the linker to link other binaries instead.)
 
+.. note:: When using an external build process with PSRAM, remember to add ``-mfix-esp32-psram-cache-issue`` to the C compiler arguments. See :ref:`CONFIG_SPIRAM_CACHE_WORKAROUND` for details of this flag.
 
 .. _esp-idf-template: https://github.com/espressif/esp-idf-template
 .. _GNU Make Manual: https://www.gnu.org/software/make/manual/make.html

tools/ci/test_build_system_cmake.sh

@@ -328,6 +328,17 @@ function run_tests()
     grep "CONFIG_PARTITION_TABLE_OFFSET=0x10000" sdkconfig || failure "The define from sdkconfig.defaults should be into sdkconfig"
     grep "CONFIG_PARTITION_TABLE_TWO_OTA=y" sdkconfig || failure "The define from sdkconfig should be into sdkconfig"
 
+    print_status "Building a project with CMake library imported and PSRAM workaround, all files compile with workaround"
+    cp sdkconfig sdkconfig.psram
+    rm -rf build
+    echo "CONFIG_SPIRAM_SUPPORT=y" >> sdkconfig.psram
+    echo "CONFIG_SPIRAM_CACHE_WORKAROUND=y" >> sdkconfig.psram
+    # note: we do 'reconfigure' here, as we just need to run cmake
+    idf.py -C $IDF_PATH/examples/build_system/cmake/import_lib -B `pwd`/build reconfigure -D SDKCONFIG="`pwd`/sdkconfig.psram"
+    grep -q '"command"' build/compile_commands.json || failure "compile_commands.json missing or has no no 'commands' in it"
+    (grep '"command"' build/compile_commands.json | grep -v mfix-esp32-psram-cache-issue) && failure "All commands in compile_commands.json should use PSRAM cache workaround"
+    rm sdkconfig.psram
+
     print_status "All tests completed"
     if [ -n "${FAILURES}" ]; then
         echo "Some failures were detected:"

tools/cmake/utilities.cmake

@@ -73,30 +73,6 @@ function(move_if_different source destination)
 
 endfunction()
 
-
-# add_compile_options variant for C++ code only
-#
-# This adds global options, set target properties for
-# component-specific flags
-function(add_cxx_compile_options)
-    foreach(option ${ARGV})
-        # note: the Visual Studio Generator doesn't support this...
-        add_compile_options($<$<COMPILE_LANGUAGE:CXX>:${option}>)
-    endforeach()
-endfunction()
-
-# add_compile_options variant for C code only
-#
-# This adds global options, set target properties for
-# component-specific flags
-function(add_c_compile_options)
-    foreach(option ${ARGV})
-        # note: the Visual Studio Generator doesn't support this...
-        add_compile_options($<$<COMPILE_LANGUAGE:C>:${option}>)
-    endforeach()
-endfunction()
-
-
 # target_add_binary_data adds binary data into the built target,
 # by converting it to a generated source file which is then compiled
 # to a binary object as part of the build