Native CMake integration

[gabrielecastellano]

This creates a root CMakeLists that can be used to directly configure and build the project natively.

For instance:

$ mkdir cmake-cache && cd cmake-cache
$ cmake -DBUILD_SIM=ON -G "Unix Makefiles" ..
$ cmake --build . -j 103

This can be helpful for developing (code inspection features) and for future maintenance in general.

Works with PR aliyun/ns-3-alibabacloud#9 for the ns3 subproject.

(tested with simulator only)

[Copilot]

Pull request overview

Adds a top-level CMake entrypoint to configure/build SimAI “natively” (without the existing wrapper scripts), primarily targeting the ns-3 simulator workflow and integrating Astra-sim sources into the ns-3 tree during configuration.

Changes:

• Introduces a new root CMakeLists.txt to drive builds of the simulator (and optionally analytical/phy targets).
• Adjusts astra_ns3 subproject CMake to only default CMAKE_BUILD_TYPE when unset.
• Updates .gitignore to ignore additional build/config artifacts (including generic **/build and **/cmake-cache).

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 5 comments.

File	Description
CMakeLists.txt	New root CMake configuration orchestrating Astra-sim + ns-3 build and creating a simulator symlink
astra-sim-alibabacloud/build/astra_ns3/CMakeLists.txt	Safer defaulting of CMAKE_BUILD_TYPE (doesn’t clobber user-provided value)
.gitignore	Adds ignores for config/build artifacts and introduces broad **/build / **/cmake-cache patterns

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[Copilot]

RESULT_DIR has a stray } in the path ("${CMAKE_CURRENT_SOURCE_DIR}}/result"), which will produce an invalid directory name and can break directory creation. Please fix the path string (and consider aligning the directory name with the repo’s existing results/ vs result/ conventions so outputs land in the intended ignored location).

[Copilot]

The CLEAN_BUILD block references NS3_DIR, but this variable is never defined in this CMake file (only NS3_SRC_DIR is). This makes the clean operation incorrect and likely leaves stale ns-3 build artifacts behind (or removes the wrong path if NS3_DIR is set externally). Use the correct variable/path for the ns-3 build and cmake-cache directories.

Suggested change

	file(REMOVE_RECURSE "${NS3_DIR}/simulation/build")
	file(REMOVE_RECURSE "${NS3_DIR}/simulation/cmake-cache")
	file(REMOVE_RECURSE "${NS3_SRC_DIR}/build")
	file(REMOVE_RECURSE "${NS3_SRC_DIR}/cmake-cache")

[Copilot]

file(GLOB_RECURSE ... "${ASTRA_SIM_DIR}/*") will also return directories by default, and the loop then calls configure_file(... COPYONLY) on each entry. Passing a directory to configure_file fails at configure time. Configure the glob to exclude directories (e.g., LIST_DIRECTORIES false) or filter out directories before copying.

[Copilot]

Removing ${BUILD_DIR} (which is ${CMAKE_CURRENT_BINARY_DIR}) during the configure step is unsafe because it deletes the active build tree (including CMake’s own files) while CMake is running. If you want a “clean” option, prefer generating a separate custom target/script that runs outside the configure step, or only delete a dedicated subdirectory owned by this project (not the entire binary dir).

Suggested change

	message(STATUS "Cleaning build directory: ${BUILD_DIR}")
	file(REMOVE_RECURSE ${BUILD_DIR})
	file(REMOVE_RECURSE "${NS3_DIR}/simulation/build")
	file(REMOVE_RECURSE "${NS3_DIR}/simulation/cmake-cache")
	file(MAKE_DIRECTORY ${BUILD_DIR})
	endif()
	message(STATUS "Cleaning NS3 simulation build directories")
	file(REMOVE_RECURSE "${NS3_DIR}/simulation/build")
	file(REMOVE_RECURSE "${NS3_DIR}/simulation/cmake-cache")
	endif()

[Copilot]

Using add_definitions("-Wall -g") injects flags globally (and -g will also apply to Release unless overridden). Prefer add_compile_options / target_compile_options and make debug info conditional on the build type so Release builds aren’t forced to include -g.

Suggested change

	add_definitions("-Wall -g")
	if(NOT CMAKE_BUILD_TYPE)
	set(CMAKE_BUILD_TYPE "Debug" CACHE STRING "Default build type" FORCE)
	endif()
	add_compile_options(-Wall)
	if(NOT CMAKE_BUILD_TYPE)
	set(CMAKE_BUILD_TYPE "Debug" CACHE STRING "Default build type" FORCE)
	endif()
	if (CMAKE_BUILD_TYPE STREQUAL "Debug")
	add_compile_options(-g)
	endif()