RDKE-1024 : Add target toolchain libs feed support for docker

[sreejithravi086]

No description provided.

[Copilot]

Pull request overview

This pull request adds support for a target toolchain libraries feed for Docker builds in the RDK build system. The changes enable the system to download and use prebuilt toolchain libraries from a remote feed when building for Docker containers, as an alternative to building them locally.

Changes:

• Introduces a new TOOLCHAIN_LAYER_ARCH architecture identifier for toolchain packages
• Adds conditional logic to populate IPK_FEED_URIS with a toolchain library feed when appropriate
• Reclassifies several core toolchain packages (glibc, libgcc, gcc-runtime, gcc-sanitizers) to use the toolchain architecture instead of the OSS layer architecture

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[Copilot]

The conditional logic in this line is complex and could be difficult to maintain. Consider refactoring this into a helper function that clearly expresses the intent. For example:

def should_add_toolchain_feed_uri(d):
    """
    Add toolchain feed URI if:
    - TOOLCHAIN_TARGET_LIBS_URI is defined AND
    - (Docker feed is not enabled OR prebuilt directory doesn't exist)
    """
    if not d.getVar('TOOLCHAIN_TARGET_LIBS_URI'):
        return False
    
    docker_feed_enabled = d.getVar('ENABLE_DOCKER_TARGET_TOOLCHAIN_FEED') == '1'
    prebuilt_dir = d.getVar('PREBUILT_TOOLCHAIN_TARGET_LIBS') or ''
    prebuilt_exists = os.path.isdir(prebuilt_dir)
    
    return not docker_feed_enabled or not prebuilt_exists

This would make the code more readable and easier to test. The inline expression could then be simplified to use this helper function.

[Copilot]

The variables ENABLE_DOCKER_TARGET_TOOLCHAIN_FEED and PREBUILT_TOOLCHAIN_TARGET_LIBS are used in the conditional logic but are not defined or documented in this file. Consider adding comments to document:

1. What ENABLE_DOCKER_TARGET_TOOLCHAIN_FEED controls (expected values and behavior)
2. What PREBUILT_TOOLCHAIN_TARGET_LIBS should contain (expected to be a directory path)
3. The relationship between these variables and TOOLCHAIN_TARGET_LIBS_URI

This would help users understand how to configure the toolchain feed mechanism and when each approach is used.

Suggested change

	PACKAGE_EXTRA_ARCHS:append = " ${TOOLCHAIN_LAYER_ARCH}"
	PACKAGE_EXTRA_ARCHS:append = " ${TOOLCHAIN_LAYER_ARCH}"
	# Toolchain feed configuration:
	# - TOOLCHAIN_TARGET_LIBS_URI:
	# URI of the remote IPK feed that provides target toolchain libraries
	# for ${TOOLCHAIN_LAYER_ARCH}. When non-empty, this URI is appended
	# to IPK_FEED_URIS, unless one of the local/alternative mechanisms
	# below is in use.
	#
	# - ENABLE_DOCKER_TARGET_TOOLCHAIN_FEED:
	# When set to "1", a Docker image is expected to provide the target
	# toolchain libraries, so no remote TOOLCHAIN_TARGET_LIBS_URI feed
	# is added for ${TOOLCHAIN_LAYER_ARCH}.
	#
	# - PREBUILT_TOOLCHAIN_TARGET_LIBS:
	# Absolute path to a directory on the build host that contains
	# prebuilt target toolchain libraries. If this variable is set and
	# points to an existing directory (os.path.isdir(...)), the local
	# directory is used instead of the remote TOOLCHAIN_TARGET_LIBS_URI
	# feed.
	#
	# The IPK_FEED_URIS:append expression below adds TOOLCHAIN_TARGET_LIBS_URI
	# only when a remote feed is configured (TOOLCHAIN_TARGET_LIBS_URI != "")
	# and neither a Docker-provided feed nor a valid PREBUILT_TOOLCHAIN_TARGET_LIBS
	# directory is in use.

[Copilot]

TOOLCHAIN_LAYER_ARCH does not include LAYER_EXTENSION, unlike OSS_LAYER_ARCH which does include it (line 25). This means toolchain libraries will be shared across all layer extensions. Verify this is intentional - if different LAYER_EXTENSION values represent incompatible build configurations, toolchain libraries from different extensions might have ABI incompatibilities. If this sharing is intentional to optimize storage/bandwidth, consider adding a comment explaining this design decision.

Suggested change

	TOOLCHAIN_LAYER_ARCH = "${@get_oss_arch(d)}-toolchain"
	TOOLCHAIN_LAYER_ARCH = "${@get_oss_arch(d)}${LAYER_EXTENSION}-toolchain"