diff mbox series

[v2,03/16] scripts/kallsyms: shrink table before sorting it

Message ID 20191123160444.11251-4-yamada.masahiro@socionext.com (mailing list archive)
State New, archived
Headers show
Series scripts/kallsyms: various cleanups and optimizations | expand

Commit Message

Masahiro Yamada Nov. 23, 2019, 4:04 p.m. UTC 
Currently, build_initial_tok_table() trims unused symbols, which is
called after sort_symbol().

It is not efficient to sort the huge table that contains unused entries.
Shrink the table before sorting it.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v2:
 - New patch

 scripts/kallsyms.c | 49 +++++++++++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

Comments

Olof Johansson Dec. 7, 2019, 10:19 p.m. UTC | #1 
Hi,

On Sat, Nov 23, 2019 at 8:05 AM Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> Currently, build_initial_tok_table() trims unused symbols, which is
> called after sort_symbol().
>
> It is not efficient to sort the huge table that contains unused entries.
> Shrink the table before sorting it.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

This started showing warnings on some 32-bit ARM platforms, due to
kallsyms_relative_base changing:

 kallsyms_relative_base:
-       PTR     _text - 0
+       PTR     _text - 0xfffffffffffffe20

The assembler started complaining:

.tmp_kallsyms1.S: Assembler messages:
.tmp_kallsyms1.S:15315: Warning: right operand is a bignum; integer 0 assumed

Also, I clearly see different output with this patch reverted and
applied; I would expect no actual difference if it was correct.

Can we please revert this for 5.5 while this is being sorted out?

To reproduce, build for example am200epdkit_defconfig for ARCH=arm. I
see it with GCC 8.2.0, binutils 2.30.0.


Thanks,

-Olof
diff mbox series

Patch

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 79641874d860..de986eda41a6 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -268,6 +268,30 @@  static int symbol_valid(struct sym_entry *s)
 	return 1;
 }
 
+/* remove all the invalid symbols from the table */
+static void shrink_table(void)
+{
+	unsigned int i, pos;
+
+	pos = 0;
+	for (i = 0; i < table_cnt; i++) {
+		if (symbol_valid(&table[i])) {
+			if (pos != i)
+				table[pos] = table[i];
+			pos++;
+		} else {
+			free(table[i].sym);
+		}
+	}
+	table_cnt = pos;
+
+	/* When valid symbol is not registered, exit to error */
+	if (!table_cnt) {
+		fprintf(stderr, "No valid symbol.\n");
+		exit(1);
+	}
+}
+
 static void read_map(FILE *in)
 {
 	while (!feof(in)) {
@@ -475,23 +499,13 @@  static void forget_symbol(unsigned char *symbol, int len)
 		token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
 }
 
-/* remove all the invalid symbols from the table and do the initial token count */
+/* do the initial token count */
 static void build_initial_tok_table(void)
 {
-	unsigned int i, pos;
+	unsigned int i;
 
-	pos = 0;
-	for (i = 0; i < table_cnt; i++) {
-		if ( symbol_valid(&table[i]) ) {
-			if (pos != i)
-				table[pos] = table[i];
-			learn_symbol(table[pos].sym, table[pos].len);
-			pos++;
-		} else {
-			free(table[i].sym);
-		}
-	}
-	table_cnt = pos;
+	for (i = 0; i < table_cnt; i++)
+		learn_symbol(table[i].sym, table[i].len);
 }
 
 static void *find_token(unsigned char *str, int len, unsigned char *token)
@@ -614,12 +628,6 @@  static void optimize_token_table(void)
 
 	insert_real_symbols_in_table();
 
-	/* When valid symbol is not registered, exit to error */
-	if (!table_cnt) {
-		fprintf(stderr, "No valid symbol.\n");
-		exit(1);
-	}
-
 	optimize_result();
 }
 
@@ -756,6 +764,7 @@  int main(int argc, char **argv)
 		usage();
 
 	read_map(stdin);
+	shrink_table();
 	if (absolute_percpu)
 		make_percpus_absolute();
 	if (base_relative)