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authorZhen Lei <thunder.leizhen@huawei.com>2022-11-02 09:49:15 +0100
committerLuis Chamberlain <mcgrof@kernel.org>2022-11-13 03:47:36 +0100
commit010a0aad39fccceba4a07d30d163158a39c704f3 (patch)
tree3ab921fc7ae10c2ffd7d435c3a2a5e87548bbbf3 /scripts/kallsyms.c
parentkallsyms: Improve the performance of kallsyms_lookup_name() (diff)
downloadlinux-010a0aad39fccceba4a07d30d163158a39c704f3.tar.xz
linux-010a0aad39fccceba4a07d30d163158a39c704f3.zip
kallsyms: Correctly sequence symbols when CONFIG_LTO_CLANG=y
LLVM appends various suffixes for local functions and variables, suffixes observed: - foo.llvm.[0-9a-f]+ - foo.[0-9a-f]+ Therefore, when CONFIG_LTO_CLANG=y, kallsyms_lookup_name() needs to truncate the suffix of the symbol name before comparing the local function or variable name. Old implementation code: - if (strcmp(namebuf, name) == 0) - return kallsyms_sym_address(i); - if (cleanup_symbol_name(namebuf) && strcmp(namebuf, name) == 0) - return kallsyms_sym_address(i); The preceding process is traversed by address from low to high. That is, for those with the same name after the suffix is removed, the one with the smallest address is returned first. Therefore, when sorting in the tool, if the raw names are the same, they should be sorted by address in ascending order. ASCII[.] = 2e ASCII[0-9] = 30,39 ASCII[A-Z] = 41,5a ASCII[_] = 5f ASCII[a-z] = 61,7a According to the preceding ASCII code values, the following sorting result is strictly followed. --------------------------------- | main-key | sub-key | |---------------------------------| | | addr_lowest | | <name> | ... | | <name>.<suffix> | ... | | | addr_highest | |---------------------------------| | <name>?<others> | | //? is [_A-Za-z0-9] --------------------------------- Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Diffstat (limited to 'scripts/kallsyms.c')
-rw-r--r--scripts/kallsyms.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index df2d93fb0e8d..07ecf7e5c49f 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -78,6 +78,7 @@ static unsigned int table_size, table_cnt;
static int all_symbols;
static int absolute_percpu;
static int base_relative;
+static int lto_clang;
static int token_profit[0x10000];
@@ -89,7 +90,7 @@ static unsigned char best_table_len[256];
static void usage(void)
{
fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] "
- "[--base-relative] in.map > out.S\n");
+ "[--base-relative] [--lto-clang] in.map > out.S\n");
exit(1);
}
@@ -411,6 +412,34 @@ static int symbol_absolute(const struct sym_entry *s)
return s->percpu_absolute;
}
+static char * s_name(char *buf)
+{
+ /* Skip the symbol type */
+ return buf + 1;
+}
+
+static void cleanup_symbol_name(char *s)
+{
+ char *p;
+
+ if (!lto_clang)
+ return;
+
+ /*
+ * ASCII[.] = 2e
+ * ASCII[0-9] = 30,39
+ * ASCII[A-Z] = 41,5a
+ * ASCII[_] = 5f
+ * ASCII[a-z] = 61,7a
+ *
+ * As above, replacing '.' with '\0' does not affect the main sorting,
+ * but it helps us with subsorting.
+ */
+ p = strchr(s, '.');
+ if (p)
+ *p = '\0';
+}
+
static int compare_names(const void *a, const void *b)
{
int ret;
@@ -421,7 +450,9 @@ static int compare_names(const void *a, const void *b)
expand_symbol(sa->sym, sa->len, sa_namebuf);
expand_symbol(sb->sym, sb->len, sb_namebuf);
- ret = strcmp(&sa_namebuf[1], &sb_namebuf[1]);
+ cleanup_symbol_name(s_name(sa_namebuf));
+ cleanup_symbol_name(s_name(sb_namebuf));
+ ret = strcmp(s_name(sa_namebuf), s_name(sb_namebuf));
if (!ret) {
if (sa->addr > sb->addr)
return 1;
@@ -855,6 +886,7 @@ int main(int argc, char **argv)
{"all-symbols", no_argument, &all_symbols, 1},
{"absolute-percpu", no_argument, &absolute_percpu, 1},
{"base-relative", no_argument, &base_relative, 1},
+ {"lto-clang", no_argument, &lto_clang, 1},
{},
};