dtc: Dynamic symbols & fixup support

Pantelis Antoniou panto at antoniou-consulting.com
Sat Jan 5 06:16:21 EST 2013


Enable the generation of symbol & fixup information for
usage with dynamic DT loading.

Passing the -@ option generates a __symbols__ node at the
root node of the resulting blob for any node labels used.

When using the /plugin/ tag all unresolved label references
be tracked in the __fixups__ node, while all local phandle
references will the tracked in the __local_fixups__ node.

This is sufficient to implement a dynamic DT object loader.

Signed-off-by: Pantelis Antoniou <panto at antoniou-consulting.com>
---
 Documentation/dt-object-internal.txt | 295 +++++++++++++++++++++++++++++++++++
 Documentation/dts-format.txt         |   7 +
 Documentation/manual.txt             |   8 +
 checks.c                             | 120 +++++++++++++-
 dtc-lexer.l                          |   5 +
 dtc-parser.y                         |  23 ++-
 dtc.c                                |   9 +-
 dtc.h                                |  38 +++++
 flattree.c                           | 139 +++++++++++++++++
 9 files changed, 635 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/dt-object-internal.txt

diff --git a/Documentation/dt-object-internal.txt b/Documentation/dt-object-internal.txt
new file mode 100644
index 0000000..a851721
--- /dev/null
+++ b/Documentation/dt-object-internal.txt
@@ -0,0 +1,295 @@
+Device Tree Dynamic Object format internals
+-------------------------------------------
+
+The Device Tree for most platforms is a static representation of
+the hardware capabilities. This is insufficient for many platforms
+that need to dynamically insert device tree fragments to the
+running kernel's live tree.
+
+This document explains the the device tree object format and the
+modifications made to the device tree compiler, which make it possible.
+
+1. Simplified Problem Definition
+--------------------------------
+
+Assume we have a platform which boots using this simplified device tree:
+
+---- foo.dts -----------------------------------------------------------------
+	/* FOO platform */
+	/ {
+		compatible = "corp,foo";
+
+		/* shared resources */
+		res: res {
+		};
+
+		/* On chip peripherals */
+		ocp: ocp {
+			/* peripherals that are always instantiated */
+			peripheral1 { ... };
+		}
+	};
+---- foo.dts -----------------------------------------------------------------
+
+We have a number of peripherals that after probing (using some undefined method)
+should result in different device tree configuration.
+
+We cannot boot with this static tree because due to the configuration of the
+foo platform there exist multiple conficting peripherals DT fragments.
+
+So for the bar peripheral we would have this:
+
+---- foo+bar.dts -------------------------------------------------------------
+	/* FOO platform + bar peripheral */
+	/ {
+		compatible = "corp,foo";
+
+		/* shared resources */
+		res: res {
+		};
+
+		/* On chip peripherals */
+		ocp: ocp {
+			/* peripherals that are always instantiated */
+			peripheral1 { ... };
+
+			/* bar peripheral */
+			bar {
+				compatible = "corp,bar";
+				... /* various properties and child nodes */
+			}
+		}
+	};
+---- foo+bar.dts -------------------------------------------------------------
+
+While for the baz peripheral we would have this:
+
+---- foo+baz.dts -------------------------------------------------------------
+	/* FOO platform + baz peripheral */
+	/ {
+		compatible = "corp,foo";
+
+		/* shared resources */
+		res: res {
+			/* baz resources */
+			baz_res: res_baz { ... };
+		};
+
+		/* On chip peripherals */
+		ocp: ocp {
+			/* peripherals that are always instantiated */
+			peripheral1 { ... };
+
+			/* baz peripheral */
+			baz {
+				compatible = "corp,baz";
+				/* reference to another point in the tree */
+				ref-to-res = <&baz_res>;
+				... /* various properties and child nodes */
+			}
+		}
+	};
+---- foo+baz.dts -------------------------------------------------------------
+
+We note that the baz case is more complicated, since the baz peripheral needs to
+reference another node in the DT tree.
+
+2. Device Tree Object Format Requirements
+-----------------------------------------
+
+Since the device tree is used for booting a number of very different hardware
+platforms it is imperative that we tread very carefully.
+
+2.a) No changes to the Device Tree binary format. We cannot modify the tree
+format at all and all the information we require should be encoded using device
+tree itself. We can add nodes that can be safely ignored by both bootloaders and
+the kernel.
+
+2.b) Changes to the DTS source format should be absolutely minimal, and should
+only be needed for the DT fragment definitions, and not the base boot DT.
+
+2.c) An explicit option should be used to instruct DTC to generate the required
+information needed for object resolution. Platforms that don't use the
+dynamic object format can safely ignore it.
+
+2.d) Finally, DT syntax changes should be kept to a minimum. It should be
+possible to express everything using the existing DT syntax.
+
+3. Implementation
+-----------------
+
+The basic unit of addressing in Device Tree is the phandle. Turns out it's
+relatively simple to extend the way phandles are generated and referenced
+so that it's possible to dynamically convert symbolic references (labels)
+to phandle values.
+
+We can roughly divide the operation into two steps.
+
+3.a) Compilation of the base board DTS file using the '-@' option
+generates a valid DT blob with an added __symbols__ node at the root node,
+containing a list of all nodes that are marked with a label.
+
+Using the foo.dts file above the following node will be generated;
+
+$ dtc -@ -O dtb -o foo.dtb -b 0 foo.dts
+$ fdtdump foo.dtb
+...
+/ {
+	...
+	res {
+		...
+		linux,phandle = <0x00000001>;
+		phandle = <0x00000001>;
+		...
+	};
+	ocp {
+		...
+		linux,phandle = <0x00000002>;
+		phandle = <0x00000002>;
+		...
+	};
+	__symbols__ {
+		res="/res";
+		ocp="/ocp";
+	};
+};
+
+Notice that all the nodes that had a label have been recorded, and that
+phandles have been generated for them.
+
+This blob can be used to boot the board normally, the __symbols__ node will
+be safely ignored both by the bootloader and the kernel (the only loss will
+be a few bytes of memory and disk space).
+
+3.b) The Device Tree fragments must be compiled with the same option but they
+must also have a tag (/plugin/) that allows undefined references to labels
+that are not present at compilation time to be recorded so that the runtime
+loader can fix them.
+
+So the bar peripheral's DTS format would be of the form:
+
+/plugin/;	/* allow undefined label references and record them */
+/ {
+	....	/* various properties for loader use; i.e. part id etc. */
+	fragment at 0 {
+		target = <&ocp>;
+		__overlay__ {
+			/* bar peripheral */
+			bar {
+				compatible = "corp,bar";
+				... /* various properties and child nodes */
+			}
+		};
+	};
+};
+
+Note that there's a target property that specifies the location where the
+contents of the overlay node will be placed, and it references the label
+in the foo.dts file.
+
+$ dtc -@ -O dtb -o bar.dtbo -b 0 bar.dts
+$ fdtdump bar.dtbo
+...
+/ {
+	... /* properties */
+	fragment at 0 {
+		target = <0xdeadbeef>;
+		__overlay__ {
+			bar {
+				compatible = "corp,bar";
+				... /* various properties and child nodes */
+			}
+		};
+	};
+	__fixups__ {
+	    ocp = "/fragment at 0:target:0";
+	};
+};
+
+No __symbols__ has been generated (no label in bar.dts).
+Note that the target's ocp label is undefined, so the phandle handle
+value is filled with the illegal value '0xdeadbeef', while a __fixups__
+node has been generated, which marks the location in the tree where
+the label lookup should store the runtime phandle value of the ocp node.
+
+The format of the __fixups__ node entry is
+
+	<label> = "<local-full-path>:<property-name>:<offset>";
+
+<label> 		Is the label we're referring
+<local-full-path>	Is the full path of the node the reference is
+<property-name>		Is the name of the property containing the
+			reference
+<offset>		The offset (in bytes) of where the property's
+			phandle value is located.
+
+Doing the same with the baz peripheral's DTS format is a little bit more
+involved, since baz contains references to local labels which require
+local fixups.
+
+/plugin/;	/* allow undefined label references and record them */
+/ {
+	....	/* various properties for loader use; i.e. part id etc. */
+	fragment at 0 {
+		target = <&res>;
+		__overlay__ {
+			/* baz resources */
+			baz_res: res_baz { ... };
+		};
+	};
+	fragment at 1 {
+		target = <&ocp>;
+		__overlay__ {
+			/* baz peripheral */
+			baz {
+				compatible = "corp,baz";
+				/* reference to another point in the tree */
+				ref-to-res = <&baz_res>;
+				... /* various properties and child nodes */
+			}
+		};
+	};
+};
+
+Note that &baz_res reference.
+
+$ dtc -@ -O dtb -o baz.dtbo -b 0 baz.dts
+$ fdtdump baz.dtbo
+...
+/ {
+	... /* properties */
+	fragment at 0 {
+		target = <0xdeadbeef>;
+		__overlay__ {
+			res_baz {
+				....
+				linux,phandle = <0x00000001>;
+				phandle = <0x00000001>;
+			};
+		};
+	};
+	fragment at 1 {
+		target = <0xdeadbeef>;
+		__overlay__ {
+			baz {
+				compatible = "corp,baz";
+				... /* various properties and child nodes */
+				res=<0x00000001>;
+			}
+		};
+	};
+	__fixups__ {
+		res = "/fragment at 0:target:0";
+		ocp = "/fragment at 1:target:0";
+	};
+	__local_fixups__ {
+		fixup = </fragment at 1/__overlay__/baz:res:0>;
+	};
+};
+
+This is similar to the bar case, but the reference of a local label by the
+baz node generates a __local_fixups__ entry that records the place that the
+local reference is being made. Since phandles are allocated starting at 1
+the run time loader must apply an offset to each phandle in every dynamic
+DT object loaded. The __local_fixups__ node records the place of every
+local reference so that the loader can apply the offset.
diff --git a/Documentation/dts-format.txt b/Documentation/dts-format.txt
index 41741df..4da515c 100644
--- a/Documentation/dts-format.txt
+++ b/Documentation/dts-format.txt
@@ -115,7 +115,14 @@ Version 1 DTS files have the overall layout:
 
 * C style (/* ... */) and C++ style (// ...) comments are supported.
 
+Device Tree Objects
+-------------------
 
+Using the plugin tag enables dynamic tree objects.
+
+	/plugin/;
+
+For the full details please see Documentation/dt-object-internal.txt
 
 	-- David Gibson <david at gibson.dropbear.id.au>
 	-- Yoder Stuart <stuart.yoder at freescale.com>
diff --git a/Documentation/manual.txt b/Documentation/manual.txt
index 65c8540..d313715 100644
--- a/Documentation/manual.txt
+++ b/Documentation/manual.txt
@@ -133,6 +133,14 @@ Options:
 	By default the most recent version is generated.
 	Relevant for dtb and asm output only.
 
+    -@
+        Dynamic resolution mode. For non /plugin/ compilations generate
+	a __symbols__ node containing a list of all nodes with a label.
+	When /plugin/ is used, unresolved references are recorded in
+	a __fixups__ node, while local phandle references are recorded
+	in a __local_fixups__ node.
+	See Documentation/dt-object-internal.txt
+
 
 The <output_version> defines what version of the "blob" format will be
 generated.  Supported versions are 1, 2, 3, 16 and 17.  The default is
diff --git a/checks.c b/checks.c
index ee96a25..970c0a3 100644
--- a/checks.c
+++ b/checks.c
@@ -457,22 +457,93 @@ static void fixup_phandle_references(struct check *c, struct node *dt,
 				     struct node *node, struct property *prop)
 {
 	struct marker *m = prop->val.markers;
+	struct fixup *f, **fp;
+	struct fixup_entry *fe, **fep;
 	struct node *refnode;
 	cell_t phandle;
+	int has_phandle_refs;
+
+	has_phandle_refs = 0;
+	for_each_marker_of_type(m, REF_PHANDLE) {
+		has_phandle_refs = 1;
+		break;
+	}
+
+	if (!has_phandle_refs)
+		return;
 
 	for_each_marker_of_type(m, REF_PHANDLE) {
 		assert(m->offset + sizeof(cell_t) <= prop->val.len);
 
 		refnode = get_node_by_ref(dt, m->ref);
-		if (! refnode) {
+		if (!refnode && !symbol_fixup_support) {
 			FAIL(c, "Reference to non-existent node or label \"%s\"\n",
-			     m->ref);
+				m->ref);
 			continue;
 		}
 
-		phandle = get_node_phandle(dt, refnode);
-		*((cell_t *)(prop->val.val + m->offset)) = cpu_to_fdt32(phandle);
+		if (!refnode) {
+			/* allocate fixup entry */
+			fe = xmalloc(sizeof(*fe));
+
+			fe->node = node;
+			fe->prop = prop;
+			fe->offset = m->offset;
+			fe->next = NULL;
+
+			/* search for an already existing fixup */
+			for_each_fixup(dt, f)
+				if (strcmp(f->ref, m->ref) == 0)
+					break;
+
+			/* no fixup found, add new */
+			if (f == NULL) {
+				f = xmalloc(sizeof(*f));
+				f->ref = m->ref;
+				f->entries = NULL;
+				f->next = NULL;
+
+				/* add it to the tree */
+				fp = &dt->fixups;
+				while (*fp)
+					fp = &(*fp)->next;
+				*fp = f;
+			}
+
+			/* and now append fixup entry */
+			fep = &f->entries;
+			while (*fep)
+				fep = &(*fep)->next;
+			*fep = fe;
+
+			/* mark the entry as unresolved */
+			phandle = 0xdeadbeef;
+		} else {
+			phandle = get_node_phandle(dt, refnode);
+
+			/* if it's a plugin, we need to record it */
+			if (symbol_fixup_support && dt->is_plugin) {
+
+				/* allocate a new local fixup entry */
+				fe = xmalloc(sizeof(*fe));
+
+				fe->node = node;
+				fe->prop = prop;
+				fe->offset = m->offset;
+				fe->next = NULL;
+
+				/* append it to the local fixups */
+				fep = &dt->local_fixups;
+				while (*fep)
+					fep = &(*fep)->next;
+				*fep = fe;
+			}
+		}
+
+		*((cell_t *)(prop->val.val + m->offset)) =
+			cpu_to_fdt32(phandle);
 	}
+
 }
 ERROR(phandle_references, NULL, NULL, fixup_phandle_references, NULL,
       &duplicate_node_names, &explicit_phandles);
@@ -651,6 +722,45 @@ static void check_obsolete_chosen_interrupt_controller(struct check *c,
 }
 TREE_WARNING(obsolete_chosen_interrupt_controller, NULL);
 
+static void check_auto_label_phandles(struct check *c, struct node *dt,
+				       struct node *node)
+{
+	struct label *l;
+	struct symbol *s, **sp;
+	int has_label;
+
+	if (!symbol_fixup_support)
+		return;
+
+	has_label = 0;
+	for_each_label(node->labels, l) {
+		has_label = 1;
+		break;
+	}
+
+	if (!has_label)
+		return;
+
+	/* force allocation of a phandle for this node */
+	(void)get_node_phandle(dt, node);
+
+	/* add the symbol */
+	for_each_label(node->labels, l) {
+
+		s = xmalloc(sizeof(*s));
+		s->label = l;
+		s->node = node;
+		s->next = NULL;
+
+		/* add it to the symbols list */
+		sp = &dt->symbols;
+		while (*sp)
+			sp = &((*sp)->next);
+		*sp = s;
+	}
+}
+NODE_WARNING(auto_label_phandles, NULL);
+
 static struct check *check_table[] = {
 	&duplicate_node_names, &duplicate_property_names,
 	&node_name_chars, &node_name_format, &property_name_chars,
@@ -669,6 +779,8 @@ static struct check *check_table[] = {
 	&avoid_default_addr_size,
 	&obsolete_chosen_interrupt_controller,
 
+	&auto_label_phandles,
+
 	&always_fail,
 };
 
diff --git a/dtc-lexer.l b/dtc-lexer.l
index 254d5af..2cef406 100644
--- a/dtc-lexer.l
+++ b/dtc-lexer.l
@@ -112,6 +112,11 @@ static int pop_input_file(void);
 			return DT_V1;
 		}
 
+<*>"/plugin/"	{
+			DPRINT("Keyword: /plugin/\n");
+			return DT_PLUGIN;
+		}
+
 <*>"/memreserve/"	{
 			DPRINT("Keyword: /memreserve/\n");
 			BEGIN_DEFAULT();
diff --git a/dtc-parser.y b/dtc-parser.y
index f412460..e444acf 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -20,6 +20,7 @@
 
 %{
 #include <stdio.h>
+#include <inttypes.h>
 
 #include "dtc.h"
 #include "srcpos.h"
@@ -56,9 +57,11 @@ static unsigned char eval_char_literal(const char *s);
 	struct node *nodelist;
 	struct reserve_info *re;
 	uint64_t integer;
+	int is_plugin;
 }
 
 %token DT_V1
+%token DT_PLUGIN
 %token DT_MEMRESERVE
 %token DT_LSHIFT DT_RSHIFT DT_LE DT_GE DT_EQ DT_NE DT_AND DT_OR
 %token DT_BITS
@@ -76,6 +79,7 @@ static unsigned char eval_char_literal(const char *s);
 
 %type <data> propdata
 %type <data> propdataprefix
+%type <is_plugin> plugindecl
 %type <re> memreserve
 %type <re> memreserves
 %type <array> arrayprefix
@@ -106,10 +110,23 @@ static unsigned char eval_char_literal(const char *s);
 %%
 
 sourcefile:
-	  DT_V1 ';' memreserves devicetree
+	  DT_V1 ';' plugindecl memreserves devicetree
 		{
-			the_boot_info = build_boot_info($3, $4,
-							guess_boot_cpuid($4));
+			$5->is_plugin = $3;
+			$5->is_root = 1;
+			the_boot_info = build_boot_info($4, $5,
+							guess_boot_cpuid($5));
+		}
+	;
+
+plugindecl:
+	/* empty */
+		{
+			$$ = 0;
+		}
+	| DT_PLUGIN ';'
+		{
+			$$ = 1;
 		}
 	;
 
diff --git a/dtc.c b/dtc.c
index a375683..30d9607 100644
--- a/dtc.c
+++ b/dtc.c
@@ -31,6 +31,7 @@ int reservenum;		/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
 int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
+int symbol_fixup_support = 0;
 
 static void fill_fullpaths(struct node *tree, const char *prefix)
 {
@@ -96,6 +97,8 @@ static void  __attribute__ ((noreturn)) usage(void)
 	fprintf(stderr, "\t-W [no-]<checkname>\n");
 	fprintf(stderr, "\t-E [no-]<checkname>\n");
 	fprintf(stderr, "\t\t\tenable or disable warnings and errors\n");
+	fprintf(stderr, "\t-@\n");
+	fprintf(stderr, "\t\tSymbols and Fixups support\n");
 	exit(3);
 }
 
@@ -118,7 +121,7 @@ int main(int argc, char *argv[])
 	minsize    = 0;
 	padsize    = 0;
 
-	while ((opt = getopt(argc, argv, "hI:O:o:V:d:R:S:p:fqb:i:vH:sW:E:"))
+	while ((opt = getopt(argc, argv, "hI:O:o:V:d:R:S:p:fqb:i:vH:sW:E:@"))
 			!= EOF) {
 		switch (opt) {
 		case 'I':
@@ -183,7 +186,9 @@ int main(int argc, char *argv[])
 		case 'E':
 			parse_checks_option(false, true, optarg);
 			break;
-
+		case '@':
+			symbol_fixup_support = 1;
+			break;
 		case 'h':
 		default:
 			usage();
diff --git a/dtc.h b/dtc.h
index 3e42a07..0c8ecf6 100644
--- a/dtc.h
+++ b/dtc.h
@@ -54,6 +54,7 @@ extern int reservenum;		/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
 extern int phandle_format;	/* Use linux,phandle or phandle properties */
+extern int symbol_fixup_support;/* enable symbols & fixup support */
 
 #define PHANDLE_LEGACY	0x1
 #define PHANDLE_EPAPR	0x2
@@ -133,6 +134,25 @@ struct label {
 	struct label *next;
 };
 
+struct fixup_entry {
+	int offset;
+	struct node *node;
+	struct property *prop;
+	struct fixup_entry *next;
+};
+
+struct fixup {
+	char *ref;
+	struct fixup_entry *entries;
+	struct fixup *next;
+};
+
+struct symbol {
+	struct label *label;
+	struct node *node;
+	struct symbol *next;
+};
+
 struct property {
 	int deleted;
 	char *name;
@@ -159,6 +179,12 @@ struct node {
 	int addr_cells, size_cells;
 
 	struct label *labels;
+
+	int is_root;
+	int is_plugin;
+	struct fixup *fixups;
+	struct symbol *symbols;
+	struct fixup_entry *local_fixups;
 };
 
 #define for_each_label_withdel(l0, l) \
@@ -182,6 +208,18 @@ struct node {
 	for_each_child_withdel(n, c) \
 		if (!(c)->deleted)
 
+#define for_each_fixup(n, f) \
+	for ((f) = (n)->fixups; (f); (f) = (f)->next)
+
+#define for_each_fixup_entry(f, fe) \
+	for ((fe) = (f)->entries; (fe); (fe) = (fe)->next)
+
+#define for_each_symbol(n, s) \
+	for ((s) = (n)->symbols; (s); (s) = (s)->next)
+
+#define for_each_local_fixup_entry(n, fe) \
+	for ((fe) = (n)->local_fixups; (fe); (fe) = (fe)->next)
+
 void add_label(struct label **labels, char *label);
 void delete_labels(struct label **labels);
 
diff --git a/flattree.c b/flattree.c
index 665dad7..6237715 100644
--- a/flattree.c
+++ b/flattree.c
@@ -262,6 +262,12 @@ static void flatten_tree(struct node *tree, struct emitter *emit,
 	struct property *prop;
 	struct node *child;
 	int seen_name_prop = 0;
+	struct symbol *sym;
+	struct fixup *f;
+	struct fixup_entry *fe;
+	char *name, *s;
+	const char *fullpath;
+	int namesz, nameoff, vallen;
 
 	if (tree->deleted)
 		return;
@@ -310,6 +316,139 @@ static void flatten_tree(struct node *tree, struct emitter *emit,
 		flatten_tree(child, emit, etarget, strbuf, vi);
 	}
 
+	if (!symbol_fixup_support)
+		goto no_symbols;
+
+	/* add the symbol nodes (if any) */
+	if (tree->symbols) {
+
+		emit->beginnode(etarget, NULL);
+		emit->string(etarget, "__symbols__", 0);
+		emit->align(etarget, sizeof(cell_t));
+
+		for_each_symbol(tree, sym) {
+
+			vallen = strlen(sym->node->fullpath);
+
+			nameoff = stringtable_insert(strbuf, sym->label->label);
+
+			emit->property(etarget, NULL);
+			emit->cell(etarget, vallen + 1);
+			emit->cell(etarget, nameoff);
+
+			if ((vi->flags & FTF_VARALIGN) && vallen >= 8)
+				emit->align(etarget, 8);
+
+			emit->string(etarget, sym->node->fullpath,
+					strlen(sym->node->fullpath));
+			emit->align(etarget, sizeof(cell_t));
+		}
+
+		emit->endnode(etarget, NULL);
+	}
+
+	/* add the fixup nodes */
+	if (tree->fixups) {
+
+		/* emit the external fixups */
+		emit->beginnode(etarget, NULL);
+		emit->string(etarget, "__fixups__", 0);
+		emit->align(etarget, sizeof(cell_t));
+
+		for_each_fixup(tree, f) {
+
+			namesz = 0;
+			for_each_fixup_entry(f, fe) {
+				fullpath = fe->node->fullpath;
+				if (fullpath[0] == '\0')
+					fullpath = "/";
+				namesz += strlen(fullpath) + 1;
+			      	namesz += strlen(fe->prop->name) + 1;
+				namesz += 32;	/* space for :<number> + '\0' */
+			}
+
+			name = xmalloc(namesz);
+
+			s = name;
+			for_each_fixup_entry(f, fe) {
+				fullpath = fe->node->fullpath;
+				if (fullpath[0] == '\0')
+					fullpath = "/";
+				snprintf(s, name + namesz - s, "%s:%s:%d",
+						fullpath,
+						fe->prop->name, fe->offset);
+				s += strlen(s) + 1;
+			}
+
+			nameoff = stringtable_insert(strbuf, f->ref);
+			vallen = s - name - 1;
+
+			emit->property(etarget, NULL);
+			emit->cell(etarget, vallen + 1);
+			emit->cell(etarget, nameoff);
+
+			if ((vi->flags & FTF_VARALIGN) && vallen >= 8)
+				emit->align(etarget, 8);
+
+			emit->string(etarget, name, vallen);
+			emit->align(etarget, sizeof(cell_t));
+
+			free(name);
+		}
+
+		emit->endnode(etarget, tree->labels);
+	}
+
+	/* add the local fixup property */
+	if (tree->local_fixups) {
+
+		/* emit the external fixups */
+		emit->beginnode(etarget, NULL);
+		emit->string(etarget, "__local_fixups__", 0);
+		emit->align(etarget, sizeof(cell_t));
+
+		namesz = 0;
+		for_each_local_fixup_entry(tree, fe) {
+			fullpath = fe->node->fullpath;
+			if (fullpath[0] == '\0')
+				fullpath = "/";
+			namesz += strlen(fullpath) + 1;
+			namesz += strlen(fe->prop->name) + 1;
+			namesz += 32;	/* space for :<number> + '\0' */
+		}
+
+		name = xmalloc(namesz);
+
+		s = name;
+		for_each_local_fixup_entry(tree, fe) {
+			fullpath = fe->node->fullpath;
+			if (fullpath[0] == '\0')
+				fullpath = "/";
+			snprintf(s, name + namesz - s, "%s:%s:%d",
+					fullpath, fe->prop->name,
+					fe->offset);
+			s += strlen(s) + 1;
+		}
+
+		nameoff = stringtable_insert(strbuf, "fixup");
+		vallen = s - name - 1;
+
+		emit->property(etarget, NULL);
+		emit->cell(etarget, vallen + 1);
+		emit->cell(etarget, nameoff);
+
+		if ((vi->flags & FTF_VARALIGN) && vallen >= 8)
+			emit->align(etarget, 8);
+
+		emit->string(etarget, name, vallen);
+		emit->align(etarget, sizeof(cell_t));
+
+		free(name);
+
+		emit->endnode(etarget, tree->labels);
+	}
+
+no_symbols:
 	emit->endnode(etarget, tree->labels);
 }
 
-- 
1.7.12



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