Add support for passing a list of exported symbols to gendwarfksyms
via stdin and filter out non-exported symbols from the output.
Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
---
scripts/gendwarfksyms/Makefile | 1 +
scripts/gendwarfksyms/dwarf.c | 53 ++++++++++++++-
scripts/gendwarfksyms/gendwarfksyms.c | 4 +-
scripts/gendwarfksyms/gendwarfksyms.h | 21 ++++++
scripts/gendwarfksyms/symbols.c | 96 +++++++++++++++++++++++++++
5 files changed, 171 insertions(+), 4 deletions(-)
create mode 100644 scripts/gendwarfksyms/symbols.c
diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile
index c1389c161f9c..623f8fc975ea 100644
--- a/scripts/gendwarfksyms/Makefile
+++ b/scripts/gendwarfksyms/Makefile
@@ -2,6 +2,7 @@ hostprogs-always-y += gendwarfksyms
gendwarfksyms-objs += gendwarfksyms.o
gendwarfksyms-objs += dwarf.o
+gendwarfksyms-objs += symbols.o
HOST_EXTRACFLAGS := -I $(srctree)/tools/include
HOSTLDLIBS_gendwarfksyms := -ldw -lelf
diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index 65a29d0bd8f4..71cfab0553da 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -5,6 +5,48 @@
#include "gendwarfksyms.h"
+static bool get_ref_die_attr(Dwarf_Die *die, unsigned int id, Dwarf_Die *value)
+{
+ Dwarf_Attribute da;
+
+ /* dwarf_formref_die returns a pointer instead of an error value. */
+ return dwarf_attr(die, id, &da) && dwarf_formref_die(&da, value);
+}
+
+static const char *get_name(Dwarf_Die *die)
+{
+ Dwarf_Attribute attr;
+
+ /* rustc uses DW_AT_linkage_name for exported symbols */
+ if (dwarf_attr(die, DW_AT_linkage_name, &attr) ||
+ dwarf_attr(die, DW_AT_name, &attr)) {
+ return dwarf_formstring(&attr);
+ }
+
+ return NULL;
+}
+
+static bool is_export_symbol(struct state *state, Dwarf_Die *die)
+{
+ Dwarf_Die *source = die;
+ Dwarf_Die origin;
+
+ state->sym = NULL;
+
+ /* If the DIE has an abstract origin, use it for type information. */
+ if (get_ref_die_attr(die, DW_AT_abstract_origin, &origin))
+ source = &origin;
+
+ state->sym = symbol_get(get_name(die));
+
+ /* Look up using the origin name if there are no matches. */
+ if (!state->sym && source != die)
+ state->sym = symbol_get(get_name(source));
+
+ state->die = *source;
+ return !!state->sym;
+}
+
/*
* Type string processing
*/
@@ -40,7 +82,7 @@ int process_die_container(struct state *state, Dwarf_Die *die,
}
/*
- * Symbol processing
+ * Exported symbol processing
*/
static int process_subprogram(struct state *state, Dwarf_Die *die)
{
@@ -67,10 +109,15 @@ static int process_exported_symbols(struct state *state, Dwarf_Die *die)
/* Possible exported symbols */
case DW_TAG_subprogram:
case DW_TAG_variable:
+ if (!is_export_symbol(state, die))
+ return 0;
+
+ debug("%s", state->sym->name);
+
if (tag == DW_TAG_subprogram)
- check(process_subprogram(state, die));
+ check(process_subprogram(state, &state->die));
else
- check(process_variable(state, die));
+ check(process_variable(state, &state->die));
return 0;
default:
diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c
index 27f2d6423c45..d209b237766b 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.c
+++ b/scripts/gendwarfksyms/gendwarfksyms.c
@@ -27,7 +27,7 @@ static const struct {
static int usage(void)
{
- error("usage: gendwarfksyms [options] elf-object-file ...");
+ error("usage: gendwarfksyms [options] elf-object-file ... < symbol-list");
return -1;
}
@@ -105,6 +105,8 @@ int main(int argc, const char **argv)
if (parse_options(argc, argv) < 0)
return usage();
+ check(symbol_read_exports(stdin));
+
for (n = 0; n < object_count; n++) {
Dwfl *dwfl;
int fd;
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
index 5ab7ce7d4efb..03f3e408a839 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -7,9 +7,11 @@
#include <elfutils/libdw.h>
#include <elfutils/libdwfl.h>
#include <linux/hashtable.h>
+#include <linux/jhash.h>
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
+#include <string.h>
#ifndef __GENDWARFKSYMS_H
#define __GENDWARFKSYMS_H
@@ -56,6 +58,23 @@ extern bool debug;
/* Error == negative values */
#define checkp(expr) __check(expr, __res < 0, __res)
+/*
+ * symbols.c
+ */
+
+static inline u32 name_hash(const char *name)
+{
+ return jhash(name, strlen(name), 0);
+}
+
+struct symbol {
+ const char *name;
+ struct hlist_node name_hash;
+};
+
+extern int symbol_read_exports(FILE *file);
+extern struct symbol *symbol_get(const char *name);
+
/*
* dwarf.c
*/
@@ -63,6 +82,8 @@ extern bool debug;
struct state {
Dwfl_Module *mod;
Dwarf *dbg;
+ struct symbol *sym;
+ Dwarf_Die die;
};
typedef int (*die_callback_t)(struct state *state, Dwarf_Die *die);
diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c
new file mode 100644
index 000000000000..673ad9cf9e77
--- /dev/null
+++ b/scripts/gendwarfksyms/symbols.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 Google LLC
+ */
+
+#include "gendwarfksyms.h"
+
+#define SYMBOL_HASH_BITS 15
+static DEFINE_HASHTABLE(symbol_names, SYMBOL_HASH_BITS);
+
+typedef int (*symbol_callback_t)(struct symbol *, void *arg);
+
+static int for_each(const char *name, symbol_callback_t func, void *data)
+{
+ struct hlist_node *tmp;
+ struct symbol *match;
+
+ if (!name || !*name)
+ return 0;
+
+ hash_for_each_possible_safe(symbol_names, match, tmp, name_hash,
+ name_hash(name)) {
+ if (strcmp(match->name, name))
+ continue;
+
+ if (func)
+ check(func(match, data));
+
+ return 1;
+ }
+
+ return 0;
+}
+
+static bool is_exported(const char *name)
+{
+ return checkp(for_each(name, NULL, NULL)) > 0;
+}
+
+int symbol_read_exports(FILE *file)
+{
+ struct symbol *sym;
+ char *line = NULL;
+ char *name = NULL;
+ size_t size = 0;
+ int nsym = 0;
+
+ while (getline(&line, &size, file) > 0) {
+ if (sscanf(line, "%ms\n", &name) != 1) {
+ error("malformed input line: %s", line);
+ return -1;
+ }
+
+ free(line);
+ line = NULL;
+
+ if (is_exported(name))
+ continue; /* Ignore duplicates */
+
+ sym = malloc(sizeof(struct symbol));
+ if (!sym) {
+ error("malloc failed");
+ return -1;
+ }
+
+ sym->name = name;
+ name = NULL;
+
+ hash_add(symbol_names, &sym->name_hash, name_hash(sym->name));
+ ++nsym;
+
+ debug("%s", sym->name);
+ }
+
+ if (line)
+ free(line);
+
+ debug("%d exported symbols", nsym);
+ return 0;
+}
+
+static int get_symbol(struct symbol *sym, void *arg)
+{
+ struct symbol **res = arg;
+
+ *res = sym;
+ return 0;
+}
+
+struct symbol *symbol_get(const char *name)
+{
+ struct symbol *sym = NULL;
+
+ for_each(name, get_symbol, &sym);
+ return sym;
+}
--
2.46.0.184.g6999bdac58-goog
