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Fix PR c++/23373: GDB hangs when printing a struct with a static member of itself

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This patch fixes a failure that happens when a structure has a static
member whose type is the same as itself.  From the bug report:

  Example code:
  struct A
  {
      static A Empty;
      int a;
  };

  int main(void) {
      A a;
      return 0;
  }

  Output:
  (gdb) ptype/o A
  /* offset    |  size */  type = struct A {
			     static struct A {
				 static struct A {
				     static struct A {
					 static struct A {
					     static struct A {
						 static struct A {
						     ... # infinite loop

The problem here is that GDB is not taking into account the fact that
static members inside a class/struct are not stored in the
class/struct, and therefore they should not be accounted for during
the display of the offsets/sizes.  The fix is simple: we just check if
the field we're dealing with (on
c-typeprint.c:c_type_print_base_struct_union) is static, and if it is
then we don't iterate over it.

This patch also adds a new test for this case, and doesn't introduce
any regressions.  I believe it is important enough to be included in
the 8.2 branch.

OK?

gdb/ChangeLog:
2018-07-11  Sergio Durigan Junior  <sergiodj@redhat.com>

	PR c++/23373
	* c-typeprint.c (c_type_print_base_struct_union): Don't print
	offsets/sizes for static members of a class/struct.

gdb/testsuite/ChangeLog:
2018-07-11  Sergio Durigan Junior  <sergiodj@redhat.com>

	PR c++/23373
	* gdb.base/ptype-offsets.cc (struct static_member): New
	struct.
	(main) <stmember>: New variable.
	* gdb.base/ptype-offsets.exp: Add test for printing a struct
	with a static member in it.
This commit is contained in:
Sergio Durigan Junior 2018-07-07 17:16:55 -04:00
parent cb19713281
commit 16ff70ddd4
5 changed files with 35 additions and 1 deletions
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6
gdb/ChangeLog
View file

@ -1,3 +1,9 @@
2018-07-11 Sergio Durigan Junior <sergiodj@redhat.com>
PR c++/23373
* c-typeprint.c (c_type_print_base_struct_union): Don't print
offsets/sizes for static members of a class/struct.
2018-07-11 Alan Hayward <alan.hayward@arm.com>
* target-descriptions.c (tdesc_register_bitsize): Rename.

2
gdb/c-typeprint.c
View file

@ -1168,7 +1168,7 @@ c_type_print_base_struct_union (struct type *type, struct ui_file *stream,
int newshow = show - 1;
if (flags->print_offsets
if (!is_static && flags->print_offsets
&& (TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_STRUCT
|| TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_UNION))
{

9
gdb/testsuite/ChangeLog
View file

@ -1,3 +1,12 @@
2018-07-11 Sergio Durigan Junior <sergiodj@redhat.com>
PR c++/23373
* gdb.base/ptype-offsets.cc (struct static_member): New
struct.
(main) <stmember>: New variable.
* gdb.base/ptype-offsets.exp: Add test for printing a struct
with a static member in it.
2018-07-10 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.base/watchpoint-reuse-slot.exp: Test with hardware

8
gdb/testsuite/gdb.base/ptype-offsets.cc
View file

@ -177,6 +177,13 @@ struct asd
void *f16;
};
/* See PR c++/23373. */
struct static_member
{
static static_member Empty;
int abc;
};
int
main (int argc, char *argv[])
@ -188,6 +195,7 @@ main (int argc, char *argv[])
struct tyu e;
struct asd f;
uint8_t i;
static_member stmember;
return 0;
}

11
gdb/testsuite/gdb.base/ptype-offsets.exp
View file

@ -328,3 +328,14 @@ gdb_test_multiple "$test" "$test" {
pass $test
}
}
# Test that printing a struct with a static member of itself doesn't
# get us into an infinite loop.
gdb_test "ptype/o static_member" \
[multi_line \
{/\* offset | size \*/ type = struct static_member \{} \
{ static static_member Empty;} \
{\/* 0 | 4 \*/ int abc;} \
{} \
{ /\* total size \(bytes\): 4 \*/} \
{ \}}]