Re: [PATCH v3 11/18] dtc: Move first-reference handling out of the grammar

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

[-- Attachment #1: Type: text/plain, Size: 4415 bytes --]

On Fri, Nov 06, 2026 at 12:51:38PM -0700, Simon Glass wrote:
> In a plugin, the first top-level fragment can refer to a label or path
> instead of being the root node. The grammar action for this holds its
> merge logic, which makes an overlay fragment in a new tree.
> 
> Move it into a new merge_first_ref(), passing it a struct fragment for
> the reference and node. This is the last user of is_ref_relative() in
> the grammar, so make that function static.
> 
> The output does not change.
> 
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Simon Glass <sjg@chromium.org>

I hope the first fragment will be less special cased than this in the
end, but this looks fine as an interim step.

> ---
> 
> (no changes since v2)
> 
> Changes in v2:
> - Use dt_ref instead of fragment_ref
> - Return true on success from merge_first_ref()
> 
>  dtc-parser.y | 13 +++++--------
>  dtc.h        |  2 +-
>  livetree.c   | 30 +++++++++++++++++++++++++++++-
>  3 files changed, 35 insertions(+), 10 deletions(-)
> 
> diff --git a/dtc-parser.y b/dtc-parser.y
> index 8d505a1..abeee0d 100644
> --- a/dtc-parser.y
> +++ b/dtc-parser.y
> @@ -163,19 +163,16 @@ devicetree:
>  		}
>  	| dt_ref nodedef
>  		{
> +			struct fragment *f;
> +
> +			f = build_fragment_ref(NULL, NULL, $1, &@1, $2);
>  			/*
>  			 * We rely on the rule being always:
>  			 *   versioninfo plugindecl memreserves devicetree
>  			 * so $-1 is what we want (plugindecl)
>  			 */
> -			if (!($<flags>-1 & DTSF_PLUGIN))
> -				ERROR(&@2, "Label or path %s not found", $1);
> -			else if (is_ref_relative($1))
> -				ERROR(&@2, "Label-relative reference %s not supported in plugin", $1);
> -			$$ = add_orphan_node(
> -					name_node(build_node(NULL, NULL, NULL),
> -						  ""),
> -					$2, $1);
> +			if (!merge_first_ref(&$$, f, $<flags>-1 & DTSF_PLUGIN))
> +				treesource_error = true;
>  		}
>  	| devicetree DT_LABEL dt_ref nodedef
>  		{
> diff --git a/dtc.h b/dtc.h
> index 9b4389b..1befd5c 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -372,7 +372,7 @@ struct fragment *build_fragment_omit_if_no_ref(char *ref,
>  					       struct srcpos *ref_srcpos);
>  struct fragment *append_fragment(struct fragment *list, struct fragment *new);
>  void free_fragment(struct fragment *f);
> -bool is_ref_relative(const char *ref);
> +bool merge_first_ref(struct node **dtp, struct fragment *f, bool plugin);
>  bool merge_ref(struct node *dt, struct fragment *f, bool plugin);
>  bool merge_delete_node(struct node *dt, struct fragment *f);
>  bool merge_omit_if_no_ref(struct node *dt, struct fragment *f);
> diff --git a/livetree.c b/livetree.c
> index 7ab9437..26d39df 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -568,11 +568,39 @@ struct dt_info *build_dt_info(unsigned int dtsflags,
>  }
>  
>  /* Check whether a reference is relative to a label, e.g. &{label/node} */
> -bool is_ref_relative(const char *ref)
> +static bool is_ref_relative(const char *ref)
>  {
>  	return ref[0] != '/' && strchr(&ref[1], '/');
>  }
>  
> +/*
> + * Make the tree at *dtp from a first fragment which refers to a label or path,
> + * rather than being the root node. This is only valid in a plugin, where the
> + * fragment becomes an overlay fragment.
> + *
> + * Returns true on success, false on an error, which has been reported.
> + */
> +bool merge_first_ref(struct node **dtp, struct fragment *f, bool plugin)
> +{
> +	bool ok = true;
> +
> +	if (!plugin) {
> +		srcpos_error(f->node->srcpos, "Error",
> +			     "Label or path %s not found", f->ref);
> +		ok = false;
> +	} else if (is_ref_relative(f->ref)) {
> +		srcpos_error(f->node->srcpos, "Error",
> +			     "Label-relative reference %s not supported in plugin",
> +			     f->ref);
> +		ok = false;
> +	}
> +	/* Make a new, empty tree with a fragment@N node for the reference */
> +	*dtp = add_orphan_node(name_node(build_node(NULL, NULL, NULL), ""),
> +			       f->node, f->ref);
> +
> +	return ok;
> +}
> +
>  /*
>   * 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.
> -- 
> 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 --]