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[doc patchv2] coding style: 0 vs. NULL + [patch] Code cleanup: skip.c
On Tue, 11 Dec 2012 13:00:57 +0100, Joel Brobecker wrote:
> Same here. I tend to prefer explicit checks.
OK, updated.
Thanks,
Jan
gdb/doc/
2012-12-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdbint.texinfo (Coding Standards) (C Usage): New rule for 0 vs. NULL.
gdb/
2012-12-11 Jan Kratochvil <jan.kratochvil@redhat.com>
Code cleanup.
* skip.c (skip_function_command, skip_file_command, skip_info): Remove
unused forward declarations.
(skip_file_command): Make variables symtab and filename targets const.
Use proper 0 vs. NULL constant everywhere.
(skip_function_command): Use proper 0 vs. NULL constant everywhere.
Include empty line after declarations. Use GNU spacing in a comment.
Do not use strlen for end of string check.
(skip_info): Use proper 0 vs. NULL constant everywhere. Add column 5
comments.
(skip_enable_command, skip_disable_command, skip_delete_command)
(add_skiplist_entry): Use proper 0 vs. NULL constant everywhere.
(function_pc_is_marked_for_skip): Make variable filename target const.
Use proper 0 vs. NULL constant everywhere. Fix GNU non-compliant
comment formatting.
(skip_re_set): Add empty line after function comment. Use proper 0 vs.
NULL constant everywhere. Include empty line after declarations. Make
variable symtab target const. Do not use strlen for end of string
check.
diff --git a/gdb/doc/gdbint.texinfo b/gdb/doc/gdbint.texinfo
index 5dbf7bf..bb7e5e5 100644
--- a/gdb/doc/gdbint.texinfo
+++ b/gdb/doc/gdbint.texinfo
@@ -5907,6 +5907,25 @@ protected with parentheses.)
Declarations like @samp{struct foo *} should be used in preference to
declarations like @samp{typedef struct foo @{ @dots{} @} *foo_ptr}.
+Zero constant (@code{0}) is not interchangeable with a null pointer
+constant (@code{NULL}) anywhere. @sc{gcc} does not give a warning for
+such interchange. Specifically:
+
+@multitable @columnfractions .2 .5
+@item incorrect
+@tab @code{if (pointervar) @{@}}
+@item incorrect
+@tab @code{if (!pointervar) @{@}}
+@item incorrect
+@tab @code{if (pointervar != 0) @{@}}
+@item incorrect
+@tab @code{if (pointervar == 0) @{@}}
+@item correct
+@tab @code{if (pointervar != NULL) @{@}}
+@item correct
+@tab @code{if (pointervar == NULL) @{@}}
+@end multitable
+
@subsection Function Prototypes
@cindex function prototypes
diff --git a/gdb/skip.c b/gdb/skip.c
index 9041b85..f07edd3 100644
--- a/gdb/skip.c
+++ b/gdb/skip.c
@@ -62,10 +62,6 @@ struct skiplist_entry
struct skiplist_entry *next;
};
-static void skip_function_command (char *arg, int from_tty);
-static void skip_file_command (char *arg, int from_tty);
-static void skip_info (char *arg, int from_tty);
-
static void add_skiplist_entry (struct skiplist_entry *e);
static void skip_function_pc (CORE_ADDR pc, const char *name,
struct gdbarch *arch,
@@ -86,16 +82,16 @@ static void
skip_file_command (char *arg, int from_tty)
{
struct skiplist_entry *e;
- struct symtab *symtab;
+ const struct symtab *symtab;
int pending = 0;
- char *filename = 0;
+ const char *filename = NULL;
/* If no argument was given, try to default to the last
displayed codepoint. */
- if (arg == 0)
+ if (arg == NULL)
{
symtab = get_last_displayed_symtab ();
- if (symtab == 0)
+ if (symtab == NULL)
error (_("No default file now."));
else
filename = symtab->filename;
@@ -103,7 +99,7 @@ skip_file_command (char *arg, int from_tty)
else
{
symtab = lookup_symtab (arg);
- if (symtab == 0)
+ if (symtab == NULL)
{
fprintf_filtered (gdb_stderr, _("No source file named %s.\n"), arg);
if (!nquery (_("\
@@ -121,7 +117,7 @@ Ignore file pending future shared library load? ")))
e->filename = xstrdup (filename);
e->enabled = 1;
e->pending = pending;
- if (symtab != 0)
+ if (symtab != NULL)
e->gdbarch = get_objfile_arch (symtab->objfile);
add_skiplist_entry (e);
@@ -136,14 +132,15 @@ skip_function_command (char *arg, int from_tty)
const char *name = NULL;
/* Default to the current function if no argument is given. */
- if (arg == 0)
+ if (arg == NULL)
{
CORE_ADDR pc;
+
if (!last_displayed_sal_is_valid ())
error (_("No default function now."));
pc = get_last_displayed_addr ();
- if (!find_pc_partial_function (pc, &name, &func_pc, 0))
+ if (!find_pc_partial_function (pc, &name, &func_pc, NULL))
{
error (_("No function found containing current program point %s."),
paddress (get_current_arch (), pc));
@@ -152,16 +149,16 @@ skip_function_command (char *arg, int from_tty)
}
else
{
- /* Decode arg. We set funfirstline=1 so decode_line_1 will give us the
+ /* Decode arg. We set funfirstline = 1 so decode_line_1 will give us the
first line of the function specified, if it can, and so that we'll
reject variable names and the like. */
char *orig_arg = arg; /* decode_line_1 modifies the arg pointer. */
volatile struct gdb_exception decode_exception;
- struct symtabs_and_lines sals = { 0 };
+ struct symtabs_and_lines sals = { NULL };
TRY_CATCH (decode_exception, RETURN_MASK_ERROR)
{
- sals = decode_line_1 (&arg, DECODE_LINE_FUNFIRSTLINE, 0, 0);
+ sals = decode_line_1 (&arg, DECODE_LINE_FUNFIRSTLINE, NULL, 0);
}
if (decode_exception.reason < 0)
@@ -176,7 +173,7 @@ skip_function_command (char *arg, int from_tty)
Ignore function pending future shared library load? ")))
{
/* Add the pending skiplist entry. */
- skip_function_pc (0, orig_arg, 0, 1);
+ skip_function_pc (0, orig_arg, NULL, 1);
}
return;
@@ -184,7 +181,7 @@ Ignore function pending future shared library load? ")))
if (sals.nelts > 1)
error (_("Specify just one function at a time."));
- if (strlen (arg) != 0)
+ if (*arg != 0)
error (_("Junk at end of arguments."));
/* The pc decode_line_1 gives us is the first line of the function,
@@ -196,7 +193,7 @@ Ignore function pending future shared library load? ")))
CORE_ADDR func_start = 0;
struct gdbarch *arch = get_sal_arch (sal);
- if (!find_pc_partial_function (pc, &name, &func_start, 0))
+ if (!find_pc_partial_function (pc, &name, &func_start, NULL))
{
error (_("No function found containing program point %s."),
paddress (arch, pc));
@@ -221,7 +218,7 @@ skip_info (char *arg, int from_tty)
/* Count the number of rows in the table and see if we need space for a
64-bit address anywhere. */
ALL_SKIPLIST_ENTRIES (e)
- if (arg == 0 || number_is_in_list (arg, e->number))
+ if (arg == NULL || number_is_in_list (arg, e->number))
{
num_printable_entries++;
if (e->gdbarch && gdbarch_addr_bit (e->gdbarch) > 32)
@@ -230,7 +227,7 @@ skip_info (char *arg, int from_tty)
if (num_printable_entries == 0)
{
- if (arg == 0)
+ if (arg == NULL)
ui_out_message (current_uiout, 0, _("\
Not skipping any files or functions.\n"));
else
@@ -266,16 +263,16 @@ Not skipping any files or functions.\n"));
struct cleanup *entry_chain;
QUIT;
- if (arg != 0 && !number_is_in_list (arg, e->number))
+ if (arg != NULL && !number_is_in_list (arg, e->number))
continue;
entry_chain = make_cleanup_ui_out_tuple_begin_end (current_uiout,
"blklst-entry");
ui_out_field_int (current_uiout, "number", e->number); /* 1 */
- if (e->function_name != 0)
+ if (e->function_name != NULL)
ui_out_field_string (current_uiout, "type", "function"); /* 2 */
- else if (e->filename != 0)
+ else if (e->filename != NULL)
ui_out_field_string (current_uiout, "type", "file"); /* 2 */
else
internal_error (__FILE__, __LINE__, _("\
@@ -295,30 +292,30 @@ Skiplist entry should have either a filename or a function name."));
ui_out_field_string (current_uiout, "addr", ""); /* 4 */
}
- if (!e->pending && e->function_name != 0)
+ if (!e->pending && e->function_name != NULL)
{
struct symbol *sym;
gdb_assert (e->pc != 0);
sym = find_pc_function (e->pc);
- if (sym)
+ if (sym != NULL)
ui_out_field_fmt (current_uiout, "what", "%s at %s:%d",
sym->ginfo.name,
SYMBOL_SYMTAB (sym)->filename,
- sym->line);
+ sym->line); /* 5 */
else
- ui_out_field_string (current_uiout, "what", "?");
+ ui_out_field_string (current_uiout, "what", "?"); /* 5 */
}
- else if (e->pending && e->function_name != 0)
+ else if (e->pending && e->function_name != NULL)
{
ui_out_field_fmt (current_uiout, "what", "%s (PENDING)",
- e->function_name);
+ e->function_name); /* 5 */
}
- else if (!e->pending && e->filename != 0)
- ui_out_field_string (current_uiout, "what", e->filename);
- else if (e->pending && e->filename != 0)
+ else if (!e->pending && e->filename != NULL)
+ ui_out_field_string (current_uiout, "what", e->filename); /* 5 */
+ else if (e->pending && e->filename != NULL)
ui_out_field_fmt (current_uiout, "what", "%s (PENDING)",
- e->filename);
+ e->filename); /* 5 */
ui_out_text (current_uiout, "\n");
do_cleanups (entry_chain);
@@ -334,7 +331,7 @@ skip_enable_command (char *arg, int from_tty)
int found = 0;
ALL_SKIPLIST_ENTRIES (e)
- if (arg == 0 || number_is_in_list (arg, e->number))
+ if (arg == NULL || number_is_in_list (arg, e->number))
{
e->enabled = 1;
found = 1;
@@ -351,7 +348,7 @@ skip_disable_command (char *arg, int from_tty)
int found = 0;
ALL_SKIPLIST_ENTRIES (e)
- if (arg == 0 || number_is_in_list (arg, e->number))
+ if (arg == NULL || number_is_in_list (arg, e->number))
{
e->enabled = 0;
found = 1;
@@ -369,9 +366,9 @@ skip_delete_command (char *arg, int from_tty)
b_prev = 0;
ALL_SKIPLIST_ENTRIES_SAFE (e, temp)
- if (arg == 0 || number_is_in_list (arg, e->number))
+ if (arg == NULL || number_is_in_list (arg, e->number))
{
- if (b_prev != 0)
+ if (b_prev != NULL)
b_prev->next = e->next;
else
skiplist_entry_chain = e->next;
@@ -429,7 +426,7 @@ add_skiplist_entry (struct skiplist_entry *e)
skiplist entries will be in numerical order. */
e1 = skiplist_entry_chain;
- if (e1 == 0)
+ if (e1 == NULL)
skiplist_entry_chain = e;
else
{
@@ -446,7 +443,7 @@ function_pc_is_marked_for_skip (CORE_ADDR pc)
{
int searched_for_sal = 0;
struct symtab_and_line sal;
- char *filename = NULL;
+ const char *filename = NULL;
struct skiplist_entry *e;
ALL_SKIPLIST_ENTRIES (e)
@@ -458,18 +455,17 @@ function_pc_is_marked_for_skip (CORE_ADDR pc)
if (e->pc != 0 && pc == e->pc)
return 1;
- if (e->filename != 0)
+ if (e->filename != NULL)
{
- /* Get the filename corresponding to this pc, if we haven't
- * yet. */
+ /* Get the filename corresponding to this pc, if we haven't yet. */
if (!searched_for_sal)
{
sal = find_pc_line (pc, 0);
- if (sal.symtab != 0)
+ if (sal.symtab != NULL)
filename = sal.symtab->filename;
searched_for_sal = 1;
}
- if (filename != 0 && strcmp (filename, e->filename) == 0)
+ if (filename != NULL && strcmp (filename, e->filename) == 0)
return 1;
}
}
@@ -478,6 +474,7 @@ function_pc_is_marked_for_skip (CORE_ADDR pc)
}
/* Re-set the skip list after symbols have been re-loaded. */
+
void
skip_re_set (void)
{
@@ -485,13 +482,14 @@ skip_re_set (void)
ALL_SKIPLIST_ENTRIES (e)
{
- if (e->filename != 0)
+ if (e->filename != NULL)
{
/* If it's an entry telling us to skip a file, but the entry is
currently pending a solib load, let's see if we now know
about the file. */
- struct symtab *symtab = lookup_symtab (e->filename);
- if (symtab != 0)
+ const struct symtab *symtab = lookup_symtab (e->filename);
+
+ if (symtab != NULL)
{
xfree (e->filename);
e->filename = xstrdup (symtab->filename);
@@ -503,19 +501,20 @@ skip_re_set (void)
e->pending = 1;
}
}
- else if (e->function_name != 0)
+ else if (e->function_name != NULL)
{
char *func_name = e->function_name;
- struct symtabs_and_lines sals = { 0 };
+ struct symtabs_and_lines sals = { NULL };
volatile struct gdb_exception decode_exception;
TRY_CATCH (decode_exception, RETURN_MASK_ERROR)
{
- sals = decode_line_1 (&func_name, DECODE_LINE_FUNFIRSTLINE, 0, 0);
+ sals = decode_line_1 (&func_name, DECODE_LINE_FUNFIRSTLINE, NULL,
+ 0);
}
if (decode_exception.reason >= 0
- && sals.nelts == 1 && strlen (func_name) == 0)
+ && sals.nelts == 1 && *func_name == 0)
{
struct symtab_and_line sal = sals.sals[0];
CORE_ADDR pc = sal.pc;
@@ -523,7 +522,7 @@ skip_re_set (void)
struct gdbarch *arch = get_sal_arch (sal);
const char *func_name;
- if (find_pc_partial_function (pc, &func_name, &func_start, 0))
+ if (find_pc_partial_function (pc, &func_name, &func_start, NULL))
{
e->pending = 0;
e->function_name = xstrdup (func_name);