Kryczkal/cmake modularization 03

.github/actions/prepare_env/action.yaml

@@ -13,20 +13,14 @@ runs:
       shell: bash
       run: sudo "$GITHUB_WORKSPACE/scripts/env/install_deps_ubuntu.bash" --install -v
 
-    - name: Configure environment
-      env:
-        ARCH: ${{ inputs.arch }}
-      shell: bash
-      run: sudo "$GITHUB_WORKSPACE/scripts/config/configure.bash" "$ARCH" debug -v -p test_mode
-
     - name: Cache toolchain
       uses: actions/cache@v4
       id: cache-build-tools
       with:
-        key: tools-${{ inputs.arch }}-${{ hashFiles('scripts/env/toolchain_versions.txt') }}
+        key: tools-${{ inputs.arch }}-${{ hashFiles('scripts/env/toolchain_versions.txt', 'scripts/env/build_cross_compile.bash') }}
         path: tools
 
-    - name: Build toolchain
+    - name: Build toolchain and Setup PATH
       env:
         TOOLCHAIN_PATH: ${{ github.workspace }}/tools
         BUILD_PATH: ${{ github.workspace }}/build
@@ -35,16 +29,23 @@ runs:
       shell: bash
       run: |
         if [[ $BUILD_TOOLS_CACHE_HIT == 'true' ]]; then
-          echo "Toolchain is cached, skipping build"      
-          if [[ $ARCH == 'x86_64' ]]; then
-            echo "Adding x86 toolchain paths to the PATH"
-            echo "$TOOLCHAIN_PATH/i386-elf/bin" >> $GITHUB_PATH
-            echo "$TOOLCHAIN_PATH/x86_64-elf/bin" >> $GITHUB_PATH
-          else
-            echo "Unsupported arch"
-            exit 1
-          fi     
+          echo "Toolchain is cached, skipping build"
         else
           echo "Building toolchain"
           sudo "$GITHUB_WORKSPACE/scripts/env/install_toolchain.bash" "$TOOLCHAIN_PATH" "$BUILD_PATH" "$ARCH" -v
         fi
+
+        echo "Adding toolchain to PATH for subsequent steps"
+        if [[ $ARCH == 'x86_64' ]]; then
+          echo "$TOOLCHAIN_PATH/i386-elf/bin" >> $GITHUB_PATH
+          echo "$TOOLCHAIN_PATH/x86_64-elf/bin" >> $GITHUB_PATH
+        else
+          echo "Unsupported arch"
+          exit 1
+        fi
+
+    - name: Configure environment
+      env:
+        ARCH: ${{ inputs.arch }}
+      shell: bash
+      run: sudo "$GITHUB_WORKSPACE/scripts/config/configure.bash" "$ARCH" debug -v -p test_mode

alkos/CMakeLists.txt

@@ -88,9 +88,21 @@ add_subdirectory(libc)
 add_subdirectory(generated)
 add_subdirectory(kernel)
 
+get_property(BOOTABLE_KERNEL_EXECUTABLE TARGET alkos.kernel.config PROPERTY BOOTABLE_KERNEL_EXECUTABLE)
+get_property(KERNEL_MODULES TARGET alkos.kernel.config PROPERTY KERNEL_MODULES)
+get_property(KERNEL_COMMANDS TARGET alkos.kernel.config PROPERTY KERNEL_COMMANDS)
+get_property(ARCH_QEMU_COMMAND TARGET alkos.kernel.config PROPERTY ARCH_QEMU_COMMAND)
+get_property(ARCH_QEMU_NORMAL_FLAGS TARGET alkos.kernel.config PROPERTY ARCH_QEMU_NORMAL_FLAGS)
+get_property(ARCH_QEMU_TEST_FLAGS TARGET alkos.kernel.config PROPERTY ARCH_QEMU_TEST_FLAGS)
+
 alkos_ensure_defined(
-    VARS BOOTABLE_KERNEL_EXECUTABLE
-    MESSAGE "No primary kernel executable defined by the end of the configuration."
+    VARS
+        BOOTABLE_KERNEL_EXECUTABLE
+        KERNEL_MODULES
+        KERNEL_COMMANDS
+        ARCH_QEMU_COMMAND
+        ARCH_QEMU_NORMAL_FLAGS
+        ARCH_QEMU_TEST_FLAGS
 )
 
 ################################################################################

alkos/cmake/ValidationHelpers.cmake

@@ -7,8 +7,8 @@
 # alkos_ensure_defined
 #===============================================================================
 #
-# Checks if one or more variables are defined and halts with a fatal error,
-# listing all undefined variables at once.
+# Checks if one or more variables are defined (and nonempty) and halts with a 
+# fatal error, listing all undefined variables at once.
 #
 # Parameters:
 #   VARS <var>...          A list of variable names to check.
@@ -42,7 +42,7 @@ function(alkos_ensure_defined)
 
     set(undefined_vars "")
     foreach(var_name ${ARG_VARS})
-        if(NOT DEFINED ${var_name})
+        if(NOT ${var_name})
             list(APPEND undefined_vars "${var_name}")
         endif()
     endforeach()
@@ -59,3 +59,63 @@ function(alkos_ensure_defined)
         message(FATAL_ERROR "${error_message}")
     endif()
 endfunction()
+
+#===============================================================================
+# alkos_ensure_property_defined
+#===============================================================================
+#
+# Checks if a property is defined for a target and halts with a fatal error,
+# listing all undefined properties at once.
+#
+# Parameters:
+#   TARGET <target>        The target to check the properties for.
+#   PROPS <prop>...       A list of property names to check.
+#   MESSAGE <message>      (Optional) A supplementary message to append to the
+#                          standard error output. This is useful for providing
+#                          additional context or instructions to the user.
+#
+# Example:
+#   # Assume alkos.kernel.config is a target and BOOTABLE_KERNEL_EXECUTABLE
+#   # is not defined.
+#   alkos_ensure_property_defined(
+#       TARGET alkos.kernel.config
+#       PROPS BOOTABLE_KERNEL_EXECUTABLE KERNEL_MODULES
+#       MESSAGE "The BOOTABLE_KERNEL_EXECUTABLE property must be set for the KERNEL_MODULES target."
+#   )
+#
+function(alkos_ensure_property_defined)
+    set(options)
+    set(oneValueArgs TARGET MESSAGE)
+    set(multiValueArgs PROPS)
+
+    cmake_parse_arguments(ARG "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+
+    if(NOT ARG_TARGET)
+        message(FATAL_ERROR "alkos_ensure_property_defined() called without a TARGET to check.")
+    endif()
+
+    if(NOT ARG_PROPS)
+        message(FATAL_ERROR "alkos_ensure_property_defined() called without any PROPS to check.")
+    endif()
+
+    set(undefined_props "")
+    foreach(prop_name ${ARG_PROPS})
+        get_property(is_defined TARGET ${ARG_TARGET} PROPERTY ${prop_name} DEFINED)
+        if(NOT is_defined)
+            list(APPEND undefined_props "${prop_name}")
+        endif()
+    endforeach()
+
+    if(undefined_props)
+        string(JOIN ", " undefined_props_str "${undefined_props}")
+
+        set(error_message "The following required properties are not defined for target '${ARG_TARGET}': ${undefined_props_str}")
+
+        if(ARG_MESSAGE)
+            string(APPEND error_message "\n${ARG_MESSAGE}")
+        endif()
+
+        message(FATAL_ERROR "${error_message}")
+    endif()
+endfunction()
+

alkos/kernel/CMakeLists.txt

@@ -1,5 +1,25 @@
 message(STATUS "Configuring kernel...")
 
+# This target acts as a central hub for configuration data (e.g., kernel modules)
+# that needs to be communicated to the top-level CMakeLists.txt.
+add_library(alkos.kernel.config INTERFACE)
+add_library(alkos.kernel.headers INTERFACE)  # Kernel headers for exporting
+add_library(alkos.kernel.deps INTERFACE)     # Target to link all dependencies to
+#------------------------------------------------------------------------------#
+#                           Notes: alkos.kernel.deps                           #
+#------------------------------------------------------------------------------#
+# Note: Caveat - linking objects to this target also requires
+# using target_sources $<TARGET_OBJECTS:{some lib name}> syntax because
+# interface libraries are only carriers for headers and properties
+#
+#------------------------------------------------------------------------------#
+# Note: This target is used to ensure proper linking order 
+# Idea was that this is the linking "api" of the kernel
+# So that arch etc, doesn't have to care about the linking order
+# This is current unused in the intended way, but may be useful in the future
+#
+#------------------------------------------------------------------------------#
+
 ############################### Error Checking ###############################
 
 alkos_ensure_defined(
@@ -11,19 +31,6 @@ alkos_ensure_defined(
 add_compile_definitions(__ALKOS_KERNEL__=1)
 add_compile_definitions(__ALKOS_LIBK__=1) # For LIBK headers
 
-############################# Arch Dependent Vars ############################
-
-# ----------------------------------------------------------------------------
-# Arch can optionally create other executables (for chainloading, etc)
-# They need to place themselves in sysroot/boot
-# This is the list of executables that will be loaded by the bootloader as
-# modules
-set(KERNEL_MODULES "")
-# ----------------------------------------------------------------------------
-# This is the executable that the bootloader will give control to
-set(BOOTABLE_KERNEL_EXECUTABLE alkos.kernel)
-# ----------------------------------------------------------------------------
-
 ########################### Setting Sysroot Boot #############################
 
 file(MAKE_DIRECTORY ${SYSROOT}/boot)
@@ -49,91 +56,92 @@ if (CMAKE_FEATURE_FLAG_RUN_TEST_MODE)
     list(APPEND KERNEL_SOURCES ${KERNEL_TEST_SOURCES})
 endif ()
 
+
 #################################### Exec ####################################
 
-add_executable(alkos.kernel
-        ${KERNEL_SOURCES}
-)
+add_executable(alkos.kernel ${KERNEL_SOURCES})
 
 ############################### Adding Headers ###############################
 
-add_library(alkos.kernel.headers INTERFACE)
 target_include_directories(alkos.kernel.headers INTERFACE
     include
     test
     abi
 )
 
-target_link_libraries(alkos.kernel PRIVATE
-    alkos.kernel.headers
-)
-
 ########################## Configure for given Arch ##########################
 
 add_subdirectory(arch/${ARCH})
 
-############################### Error Checking ###############################
-
-alkos_ensure_defined(
-    VARS
-        BOOTABLE_KERNEL_EXECUTABLE
-        KERNEL_MODULES
-        KERNEL_COMMANDS
-        ARCH_QEMU_COMMAND
-        ARCH_QEMU_NORMAL_FLAGS
-        ARCH_QEMU_TEST_FLAGS
-        CRTI_OBJ
-        CRTN_OBJ
-)
-
-message(STATUS "Bootable kernel executable: ${BOOTABLE_KERNEL_EXECUTABLE}")
-message(STATUS "Kernel modules: ${KERNEL_MODULES}")
-message(STATUS "Kernel commands: ${KERNEL_COMMANDS}")
-
-list(LENGTH KERNEL_MODULES KERNEL_MODULES_LENGTH)
-list(LENGTH KERNEL_COMMANDS KERNEL_COMMANDS_LENGTH)
-
-# Check if the two lists are the same size
-if(NOT KERNEL_MODULES_LENGTH EQUAL KERNEL_COMMANDS_LENGTH)
-    message(FATAL_ERROR "KERNEL_MODULES and KERNEL_COMMANDS have different sizes: ${KERNEL_MODULES_LENGTH} vs ${KERNEL_COMMANDS_LENGTH}")
-endif()
+# TODO: Immediately here, error checking should happen
+# But the error checking itself fails!!! and for some reason
+# alkos_ensure_property_defined() says the property is not defined
 
 ################################# ThirdParty #################################
 
-message(STATUS "Adding third-party libraries...")
 add_subdirectory(thirdparty)
 
-################################## Linking ###################################
+target_link_libraries(alkos.kernel.deps INTERFACE
+    alkos.kernel.thirdparty
+    libk
+    AutoGenLib
+)
 
-target_link_libraries(alkos.kernel PRIVATE libk gcc ${THIRD_PARTY_LIBRARIES} AutoGenLib)
+################################ Linking Kernel ################################
+
+target_link_libraries(alkos.kernel PRIVATE
+    target.properties
+    alkos.kernel.config
+    alkos.kernel.headers
+    alkos.kernel.deps
+)
 
 ############## Linker Configuration for CXX Global Constructors ##############
-# Set the linker to link objects in the correct order
-# NOTE: ARCH cmake is expected to provide variables for global constructors
-# according to the compiler needs
 # NOTE: This linking must be done at this level as global constructors
 # should be supported on each architecture
-if (NOT DEFINED CRTI_OBJ  OR NOT DEFINED CRTN_OBJ)
-    message(FATAL_ERROR "One of: crti.o, crtn.o is not defined. Those should be defined in the ARCH CMakeLists.txt file")
-endif ()
 
-set(CMAKE_CXX_LINKER_LAUNCHER "/bin/bash -c")
-set(CMAKE_CXX_LINK_EXECUTABLE
-"/bin/bash -c \"${CMAKE_CXX_COMPILER} <CMAKE_CXX_LINK_FLAGS> <FLAGS> <LINK_FLAGS> \
-${CRTI_OBJ} \
-\$\(${CMAKE_C_COMPILER} -print-file-name=crtbegin.o\) \
-<OBJECTS> \
-\$\(${CMAKE_C_COMPILER} -print-file-name=crtend.o\) \
-${CRTN_OBJ} \
--o <TARGET> <LINK_LIBRARIES>\""
+# Retrieve our custom CRT object paths from the arch-specific configuration.
+get_property(CRTI_OBJ_PATH TARGET alkos.kernel.config PROPERTY CRTI_OBJ)
+get_property(CRTN_OBJ_PATH TARGET alkos.kernel.config PROPERTY CRTN_OBJ)
+alkos_ensure_defined(
+    VARS CRTI_OBJ_PATH CRTN_OBJ_PATH
+    MESSAGE "CRTI_OBJ/CRTN_OBJ properties were not set by the architecture-specific CMake file."
+)
+
+# Find the compiler's CRT object files at configure-time.
+execute_process(
+    COMMAND ${CMAKE_C_COMPILER} -print-file-name=crtbegin.o
+    OUTPUT_VARIABLE CRTBEGIN_OBJ_PATH
+    ERROR_VARIABLE CRTBEGIN_ERROR
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+execute_process(
+    COMMAND ${CMAKE_C_COMPILER} -print-file-name=crtend.o
+    OUTPUT_VARIABLE CRTEND_OBJ_PATH
+    ERROR_VARIABLE CRTEND_ERROR
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+
+alkos_ensure_defined(
+    VARS CRTBEGIN_OBJ_PATH CRTEND_OBJ_PATH
+    MESSAGE "Could not find compiler's crtbegin.o/crtend.o files."
 )
 
-########################## Back-Propagate Variables ##########################
+message(STATUS "Found CRT Objects:")
+message(STATUS "  crti: ${CRTI_OBJ_PATH}")
+message(STATUS "  crtbegin: ${CRTBEGIN_OBJ_PATH}")
+message(STATUS "  crtend: ${CRTEND_OBJ_PATH}")
+message(STATUS "  crtn: ${CRTN_OBJ_PATH}")
+
+# TODO:
+# The below code could technically be replaced with target_link_libraries()
+# it also should enforce the correct linking order.
+# I have done so with success, but it introduced a bug where no tests were 
+# detected in the kernel and I was unable to reslove it so gave up for now.
 
-set(BOOTABLE_KERNEL_EXECUTABLE ${BOOTABLE_KERNEL_EXECUTABLE} PARENT_SCOPE)
-set(KERNEL_MODULES ${KERNEL_MODULES} PARENT_SCOPE)
-set(KERNEL_COMMANDS ${KERNEL_COMMANDS} PARENT_SCOPE)
+# Add all objects and libraries to the kernel target in the correct link order.
+#    The linker requires: crti, crtbegin, <main objects>, <libraries>, crtend, crtn
+set(CMAKE_CXX_LINK_EXECUTABLE
+  "${CMAKE_CXX_COMPILER} <FLAGS> <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> ${CRTI_OBJ_PATH} ${CRTBEGIN_OBJ_PATH} <OBJECTS> ${CRTEND_OBJ_PATH} ${CRTN_OBJ_PATH} -o <TARGET> <LINK_LIBRARIES>"
+)
 
-set(ARCH_QEMU_COMMAND ${ARCH_QEMU_COMMAND} PARENT_SCOPE)
-set(ARCH_QEMU_NORMAL_FLAGS ${ARCH_QEMU_NORMAL_FLAGS} PARENT_SCOPE)
-set(ARCH_QEMU_TEST_FLAGS ${ARCH_QEMU_TEST_FLAGS} PARENT_SCOPE)