Re: [PATCH v3 10/18] dtc: Move labelled-reference handling out of the grammar

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 3807 bytes --]

On Fri, Nov 06, 2026 at 12:51:37PM -0700, Simon Glass wrote:
> The grammar action for a top-level label: &ref { ... } holds its merge
> logic, which adds the label to the node referred to.
> 
> Move it into merge_ref(), passing it a struct fragment with the label.
> 
> The output does not change.
> 
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> 
> (no changes since v2)
> 
> Changes in v2:
> - Combine merge_labelled_ref() into merge_ref()
> - Use dt_ref instead of fragment_ref
> 
>  dtc-parser.y | 13 ++++---------
>  livetree.c   | 14 ++++++++++----
>  2 files changed, 14 insertions(+), 13 deletions(-)
> 
> diff --git a/dtc-parser.y b/dtc-parser.y
> index 3ec9254..8d505a1 100644
> --- a/dtc-parser.y
> +++ b/dtc-parser.y
> @@ -179,16 +179,11 @@ devicetree:
>  		}
>  	| devicetree DT_LABEL dt_ref nodedef
>  		{
> -			struct node *target = get_node_by_ref($1, $3);
> -
> -			if (($<flags>-1 & DTSF_PLUGIN) && is_ref_relative($3))
> -				ERROR(&@2, "Label-relative reference %s not supported in plugin", $3);
> +			struct fragment *f;
>  
> -			if (target) {
> -				add_label(&target->labels, $2);
> -				merge_nodes(target, $4);
> -			} else
> -				ERROR(&@3, "Label or path %s not found", $3);
> +			f = build_fragment_ref($2, &@2, $3, &@3, $4);
> +			if (!merge_ref($1, f, $<flags>-1 & DTSF_PLUGIN))
> +				treesource_error = true;
>  			$$ = $1;
>  		}
>  	| devicetree dt_ref nodedef
> diff --git a/livetree.c b/livetree.c
> index 2e9a3b2..7ab9437 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -574,10 +574,12 @@ bool is_ref_relative(const char *ref)
>  }
>  
>  /*
> - * Merge a fragment which refers to a label or path into the node it refers to.
> + * Merge a fragment which refers to a label or path into the node it refers to,
> + * adding any label in the fragment to that node.
>   *
>   * In a plugin, a path always refers to the base tree and a label may do so, if
> - * it is not found. In both cases, the fragment becomes an overlay fragment.
> + * it is not found. In both cases, the fragment becomes an overlay fragment,
> + * unless it adds a label, which needs a node in the plugin itself.
>   *
>   * Returns true on success, false on an error, which has been reported.
>   */
> @@ -589,12 +591,14 @@ bool merge_ref(struct node *dt, struct fragment *f, bool plugin)
>  	assert(f->type == FRAGMENT_NODE);
>  	if (plugin) {
>  		if (is_ref_relative(f->ref)) {
> -			srcpos_error(f->ref_srcpos, "Error",
> +			srcpos_error(f->label ? f->label_srcpos : f->ref_srcpos,
> +				     "Error",

This change doesn't make sense to me - the problem is with the ref,
not the label, whether or not the label exists.

>  				     "Label-relative reference %s not supported in plugin",
>  				     f->ref);
>  			ok = false;
>  		}
> -		if (f->ref[0] == '/' || !get_node_by_ref(dt, f->ref)) {
> +		if (!f->label &&

Why does having a label preclude an orphan merge? IIRC, we can encode
this by putting label = "/fragment@XX/__overlay__" into the dtbo's
__symbols__.

> +		    (f->ref[0] == '/' || !get_node_by_ref(dt, f->ref))) {
>  			/* Add a fragment@N node for the reference */
>  			add_orphan_node(dt, f->node, f->ref);
>  			return ok;
> @@ -607,6 +611,8 @@ bool merge_ref(struct node *dt, struct fragment *f, bool plugin)
>  			     "Label or path %s not found", f->ref);
>  		return false;
>  	}
> +	if (f->label)
> +		add_label(&target->labels, f->label);
>  	merge_nodes(target, f->node);
>  
>  	return ok;
> -- 
> 2.43.0
> 
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]