[RFA] Fix leaks in macro definitions.

Philippe Waroquiers
2019-01-15T05:56:25Z

Valgrind detects leaks like the following (gdb.base/macsp.exp).
This patch fixes the 3 leaks.
Tested on debian/amd64, natively and under valgrind.

==22285== 64 (48 direct, 16 indirect) bytes in 1 blocks are definitely lost in loss record 737 of 3,377
==22285== at 0x4C2BE6D: malloc (vg_replace_malloc.c:309)
==22285== by 0x4049E7: xmalloc (common-utils.c:44)
==22285== by 0x533A20: new_macro_key(macro_table*, char const*, macro_source_file*, int) (macrotab.c:355)
==22285== by 0x53438B: macro_define_function(macro_source_file*, int, char const*, int, char const**, char const*) (macrotab.c:822)
==22285== by 0x52F945: macro_define_command(char const*, int) (macrocmd.c:409)
...
==22285== 128 (96 direct, 32 indirect) bytes in 2 blocks are definitely lost in loss record 1,083 of 3,377
==22285== at 0x4C2BE6D: malloc (vg_replace_malloc.c:309)
==22285== by 0x4049E7: xmalloc (common-utils.c:44)
==22285== by 0x533A20: new_macro_key(macro_table*, char const*, macro_source_file*, int) (macrotab.c:355)
==22285== by 0x534277: macro_define_object_internal(macro_source_file*, int, char const*, char const*, macro_special_kind) (macrotab.c:776)
==22285== by 0x52F7E0: macro_define_command(char const*, int) (macrocmd.c:414)
...
==22285== 177 bytes in 19 blocks are definitely lost in loss record 1,193 of 3,377
==22285== at 0x4C2BE6D: malloc (vg_replace_malloc.c:309)
==22285== by 0x4049E7: xmalloc (common-utils.c:44)
==22285== by 0x52F5BD: extract_identifier(char const**, int) (macrocmd.c:316)
==22285== by 0x52F77D: macro_define_command(char const*, int) (macrocmd.c:355)

gdb/ChangeLog
2019-01-15 Philippe Waroquiers <philippe.waroquiers@skynet.be>

* macrocmd.c (macro_define_command): Use a unique_xmalloc_ptr
to maintain name ownership.
* macrotab.c (macro_define_internal): New function that
factorizes macro_define_object_internal and macro_define_function
code. If the newly inserted node has replaced a existing node,
call macro_tree_delete_key to free the unused just allocated key.
(macro_define_object_internal): Use macro_define_internal.
(macro_define_function): Likewise.
(macro_undef): Free the key of the removed node.
---
gdb/macrocmd.c | 10 +++----
gdb/macrotab.c | 75 +++++++++++++++++++++++++++++---------------------
2 files changed, 48 insertions(+), 37 deletions(-)

diff --git a/gdb/macrocmd.c b/gdb/macrocmd.c
index 706a8353e2..c1c42fa910 100644
--- a/gdb/macrocmd.c
+++ b/gdb/macrocmd.c
@@ -346,14 +346,13 @@ static void
macro_define_command (const char *exp, int from_tty)
{
temporary_macro_definition new_macro;
- char *name = NULL;

if (!exp)
error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));

skip_ws (&exp);
- name = extract_identifier (&exp, 0);
- if (! name)
+ gdb::unique_xmalloc_ptr<char> name (extract_identifier (&exp, 0));
+ if (name.get () == NULL)
error (_("Invalid macro name."));
if (*exp == '(')
{
@@ -404,14 +403,15 @@ macro_define_command (const char *exp, int from_tty)
++exp;
skip_ws (&exp);

- macro_define_function (macro_main (macro_user_macros), -1, name,
+ macro_define_function (macro_main (macro_user_macros), -1, name.get (),
new_macro.argc, (const char **) new_macro.argv,
exp);
}
else
{
skip_ws (&exp);
- macro_define_object (macro_main (macro_user_macros), -1, name, exp);
+ macro_define_object (macro_main (macro_user_macros), -1, name.get (),
+ exp);
}
}

diff --git a/gdb/macrotab.c b/gdb/macrotab.c
index 7fcab4691b..b2343c8c29 100644
--- a/gdb/macrotab.c
+++ b/gdb/macrotab.c
@@ -743,21 +743,27 @@ check_for_redefinition (struct macro_source_file *source, int line,
return 0;
}

-/* A helper function to define a new object-like macro. */
+/* A helper function to define a new object-like or function-like macro
+ according to KIND. When KIND is macro_object_like,
+ the macro_special_kind must be provided as ARGC, and ARGV must be NULL.
+ When KIND is macro_function_like, ARGC and ARGV are giving the function
+ arguments. */

static void
-macro_define_object_internal (struct macro_source_file *source, int line,
- const char *name, const char *replacement,
- enum macro_special_kind kind)
+macro_define_internal (struct macro_source_file *source, int line,
+ const char *name, enum macro_kind kind,
+ int argc, const char **argv,
+ const char *replacement)
{
struct macro_table *t = source->table;
struct macro_key *k = NULL;
struct macro_definition *d;
+ splay_tree_node s;

if (! t->redef_ok)
- k = check_for_redefinition (source, line,
- name, macro_object_like,
- 0, 0,
+ k = check_for_redefinition (source, line,
+ name, kind,
+ argc, argv,
replacement);

/* If we're redefining a symbol, and the existing key would be
@@ -774,8 +780,28 @@ macro_define_object_internal (struct macro_source_file *source, int line,
return;

k = new_macro_key (t, name, source, line);
- d = new_macro_definition (t, macro_object_like, kind, 0, replacement);
- splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
+ d = new_macro_definition (t, kind, argc, argv, replacement);
+ s = splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
+ if ((struct macro_key *) s->key != k)
+ {
+ /* If the node inserted is not using k, it means we have a redefinition.
+ We must free the newly allocated k, as it will not be stored in
+ the splay tree. */
+ macro_tree_delete_key (k);
+ }
+}
+
+/* A helper function to define a new object-like macro. */
+
+static void
+macro_define_object_internal (struct macro_source_file *source, int line,
+ const char *name, const char *replacement,
+ enum macro_special_kind special_kind)
+{
+ macro_define_internal (source, line,
+ name, macro_object_like,
+ special_kind, 0,
+ replacement);
}

void
@@ -802,29 +828,12 @@ macro_define_function (struct macro_source_file *source, int line,
const char *name, int argc, const char **argv,
const char *replacement)
{
- struct macro_table *t = source->table;
- struct macro_key *k = NULL;
- struct macro_definition *d;
-
- if (! t->redef_ok)
- k = check_for_redefinition (source, line,
- name, macro_function_like,
- argc, argv,
- replacement);
-
- /* See comments about duplicate keys in macro_define_object. */
- if (k && ! key_compare (k, name, source, line))
- return;
-
- /* We should also check here that all the argument names in ARGV are
- distinct. */
-
- k = new_macro_key (t, name, source, line);
- d = new_macro_definition (t, macro_function_like, argc, argv, replacement);
- splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
+ macro_define_internal (source, line,
+ name, macro_function_like,
+ argc, argv,
+ replacement);
}

-
void
macro_undef (struct macro_source_file *source, int line,
const char *name)
@@ -841,8 +850,10 @@ macro_undef (struct macro_source_file *source, int line,
arguments like '-DFOO -UFOO -DFOO=2'. */
if (source == key->start_file
&& line == key->start_line)
- splay_tree_remove (source->table->definitions, n->key);
-
+ {
+ splay_tree_remove (source->table->definitions, n->key);
+ macro_tree_delete_key (key);
+ }
else
{
/* This function is the only place a macro's end-of-scope
--
2.20.1