[RFA] Remove a cleanup from parse_expression_for_completion

Tom Tromey
2018-02-16T23:02:20Z

changing various expression-completion functions to use std::string
rather than explicit malloc+free.

Regression tested by the buildbot.

gdb/ChangeLog
2018-02-16 Tom Tromey <tom@tromey.com>

* value.h: (extract_field_op): Update.
* eval.c (extract_field_op): Return a const char *.
* expression.h (parse_expression_for_completion): Update.
* completer.c (complete_expression): Update.
(add_struct_fields): Make fieldname const.
* parse.c (expout_completion_name): Now a std::string.
(mark_completion_tag, parse_exp_in_context_1): Update.
(parse_expression_for_completion): Change "name" to std::string*.
---
gdb/ChangeLog | 11 +++++++++++
gdb/completer.c | 22 ++++++++--------------
gdb/eval.c | 2 +-
gdb/expression.h | 3 ++-
gdb/parse.c | 20 +++++++-------------
gdb/value.h | 2 +-
6 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/gdb/completer.c b/gdb/completer.c
index a71bd368ff..c0d5778867 100644
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -962,7 +962,7 @@ location_completer_handle_brkchars (struct cmd_list_element *ignore,

static void
add_struct_fields (struct type *type, completion_list &output,
- char *fieldname, int namelen)
+ const char *fieldname, int namelen)
{
int i;
int computed_type_name = 0;
@@ -1016,12 +1016,11 @@ complete_expression (completion_tracker &tracker,
const char *text, const char *word)
{
struct type *type = NULL;
- char *fieldname;
+ std::string fieldname;
enum type_code code = TYPE_CODE_UNDEF;

/* Perform a tentative parse of the expression, to see whether a
field completion is required. */
- fieldname = NULL;
TRY
{
type = parse_expression_for_completion (text, &fieldname, &code);
@@ -1032,7 +1031,7 @@ complete_expression (completion_tracker &tracker,
}
END_CATCH

- if (fieldname && type)
+ if (!fieldname.empty () && type)
{
for (;;)
{
@@ -1045,25 +1044,20 @@ complete_expression (completion_tracker &tracker,
if (TYPE_CODE (type) == TYPE_CODE_UNION
|| TYPE_CODE (type) == TYPE_CODE_STRUCT)
{
- int flen = strlen (fieldname);
completion_list result;

- add_struct_fields (type, result, fieldname, flen);
- xfree (fieldname);
+ add_struct_fields (type, result, fieldname.c_str (),
+ fieldname.size ());
tracker.add_completions (std::move (result));
return;
}
}
- else if (fieldname && code != TYPE_CODE_UNDEF)
+ else if (!fieldname.empty () && code != TYPE_CODE_UNDEF)
{
- struct cleanup *cleanup = make_cleanup (xfree, fieldname);
-
- collect_symbol_completion_matches_type (tracker, fieldname, fieldname,
- code);
- do_cleanups (cleanup);
+ collect_symbol_completion_matches_type (tracker, fieldname.c_str (),
+ fieldname.c_str (), code);
return;
}
- xfree (fieldname);

complete_files_symbols (tracker, text, word);
}
diff --git a/gdb/eval.c b/gdb/eval.c
index 6f74c41b9f..4899011a58 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -272,7 +272,7 @@ fetch_subexp_value (struct expression *exp, int *pc, struct value **valp,
subexpression of the left-hand-side of the dereference. This is
used when completing field names. */

-char *
+const char *
extract_field_op (struct expression *exp, int *subexp)
{
int tem;
diff --git a/gdb/expression.h b/gdb/expression.h
index 030f2f08e7..f9b5b1e820 100644
--- a/gdb/expression.h
+++ b/gdb/expression.h
@@ -101,7 +101,8 @@ extern expression_up parse_expression (const char *);
extern expression_up parse_expression_with_language (const char *string,
enum language lang);

-extern struct type *parse_expression_for_completion (const char *, char **,
+extern struct type *parse_expression_for_completion (const char *,
+ std::string *,
enum type_code *);

extern expression_up parse_exp_1 (const char **, CORE_ADDR pc,
diff --git a/gdb/parse.c b/gdb/parse.c
index e3f1306a17..1d1ede4f56 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -88,7 +88,7 @@ static int expout_last_struct = -1;
static enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;

/* The token for tagged type name completion. */
-static char *expout_completion_name;
+static std::string expout_completion_name;

\f
static unsigned int expressiondebug = 0;
@@ -569,15 +569,13 @@ mark_completion_tag (enum type_code tag, const char *ptr, int length)
{
gdb_assert (parse_completion
&& expout_tag_completion_type == TYPE_CODE_UNDEF
- && expout_completion_name == NULL
+ && expout_completion_name.empty ()
&& expout_last_struct == -1);
gdb_assert (tag == TYPE_CODE_UNION
|| tag == TYPE_CODE_STRUCT
|| tag == TYPE_CODE_ENUM);
expout_tag_completion_type = tag;
- expout_completion_name = (char *) xmalloc (length + 1);
- memcpy (expout_completion_name, ptr, length);
- expout_completion_name[length] = '\0';
+ expout_completion_name = std::string (ptr, length);
}

\f
@@ -1137,8 +1135,7 @@ parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
type_stack.depth = 0;
expout_last_struct = -1;
expout_tag_completion_type = TYPE_CODE_UNDEF;
- xfree (expout_completion_name);
- expout_completion_name = NULL;
+ expout_completion_name = "";

comma_terminates = comma;

@@ -1281,7 +1278,7 @@ parse_expression_with_language (const char *string, enum language lang)
*NAME must be freed by the caller. */

struct type *
-parse_expression_for_completion (const char *string, char **name,
+parse_expression_for_completion (const char *string, std::string *name,
enum type_code *code)
{
expression_up exp;
@@ -1306,8 +1303,7 @@ parse_expression_for_completion (const char *string, char **name,
if (expout_tag_completion_type != TYPE_CODE_UNDEF)
{
*code = expout_tag_completion_type;
- *name = expout_completion_name;
- expout_completion_name = NULL;
+ *name = std::move (expout_completion_name);
return NULL;
}

@@ -1315,14 +1311,12 @@ parse_expression_for_completion (const char *string, char **name,
return NULL;

*name = extract_field_op (exp.get (), &subexp);
- if (!*name)
+ if (name->empty ())
return NULL;

/* This might throw an exception. If so, we want to let it
propagate. */
val = evaluate_subexpression_type (exp.get (), subexp);
- /* (*NAME) is a part of the EXP memory block freed below. */
- *name = xstrdup (*name);

return value_type (val);
}
diff --git a/gdb/value.h b/gdb/value.h
index e0ea22d4e5..5676d245b9 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -889,7 +889,7 @@ extern void fetch_subexp_value (struct expression *exp, int *pc,
struct value **val_chain,
int preserve_errors);

-extern char *extract_field_op (struct expression *exp, int *subexp);
+extern const char *extract_field_op (struct expression *exp, int *subexp);

extern struct value *evaluate_subexp_with_coercion (struct expression *,
int *, enum noside);
--
2.13.6