[Bug]: CMake generates 600+ include directories per compilation unit

[yktyagi]

Which component impacted?

Build

Is it regression? Good in old configuration?

No, this issue exist a long time

What happened?

PROBLEM

The CMake build configuration adds 600+ include directories (-I flags) to
individual source files. This is excessive - typical C++ projects use 20-100
include directories.

IMPACT

• Build failures in Yocto/OpenEmbedded (ARG_MAX limit exceeded)
• Fails with typical workspace path lengths (80-120 characters)
• Breaks in Docker, CI/CD, and automated build environments
• Slower compilation (compiler searches 600+ directories per file)

ERROR

fatal error: cannot execute 'cc1plus': posix_spawn: Argument list too long

CAUSE

600+ include paths × ~100 chars average = 60KB+ of path data
Combined with other compiler arguments, this exceeds Linux ARG_MAX limits.

Note: Response files don't solve this - GCC expands them before spawning
cc1plus, so the limit still applies.

SOLUTION

Reduce include directories using CMake best practices:

1. Replace include_directories() with target_include_directories()
2. Use PRIVATE visibility for internal headers
3. Use INTERFACE/PUBLIC only for headers exposed to consumers
4. Remove duplicate/redundant paths
5. Use relative paths for headers

BENEFITS

• Fixes build failures across multiple environments
• Faster compilation (20-30% improvement typical)
• Better maintainability and clearer dependencies
• Modern CMake best practices

VERIFICATION

Check compile_commands.json - most files should have 20-100 include
directories, not 600+.

What's the usage scenario when you are seeing the problem?

Others

What impacted?

Compilation of media_driver source files, specifically:

• media_driver COMMON target compilation units
• Files including: cm_def.cpp, cm_buffer_rt.cpp, cm_event_rt.cpp, cm_hal.cpp
• Affects all builds where workspace path + include directories exceed ARG_MAX
• Build environments: Yocto/OpenEmbedded, Docker, CI/CD systems

Debug Information

Build System: CMake with Ninja generator
Compiler: GCC (g++)
System: Linux (ARG_MAX: 2097152 bytes / 2MB)

Include directory count from response file:
$ grep -c "^-I" media_driver/CMakeFiles/iHD_drv_video_COMMON.dir/file.rsp
600+

Example compilation command (from build.ninja):
/path/to/g++ --sysroot=/path/to/sysroot @response_file.rsp -MD -MT

Do you want to contribute a patch to fix the issue?

No.

[rossburton]

From my very limited understanding of cmake (but having done similar for llvm), (1) and (2) should be simple to implement and result in easy gains.